text: Alpha diversity refers to the average species diversity in a habitat or specific area. How many taxa (OTU's) are detected in each sample? In ecology, the concepts of alpha diversity and beta diversity are frequently used to characterize habitats. An illustration is given below. Cheers, Tin--You received this message because you are subscribed to the Google Groups "MetaPhlAn-users" group. Alpha diversity is the diversity in a single ecosystem or sample. Learn about the large number of features and updates including Upright Orcs, Profession Changes, Class Changes and the upcoming Battle of Teldrassil questline. There is a second important challenge in the study and description of biodiversity. The diversity calculator is an excel template that allows you to calculate alpha-, beta- and gamma diversity for a set samples (input data), and to analyze similarities between the samples based on partitioning diversity in alpha and beta diversity. Microbial Community Diversity Analysis Tutorial with Phyloseq. Formulae for the remaining metrics can be found in Appendix S1. No macros or links to external workbooks are necessary. In this video Alpha, Beta and Gamma Diversity is discussed briefly. Re: Can metaphlan calculate alpha diversity and beta diversity: Duy Tin Truong: 4/5/16 12:03 PM: Hi Yun, Currently, Metaphlan does not have that feature. Beta diversities quantify spatial species turnover of samples belonging to the sama gamma scale/ group. Function rarefy finds estimated number of species for given sample size. For more information pertaining to the OTU table refer to the documentation for make_otu_table. Each of our properties was assessed by exploring how measured β‐diversity covaried with a test‐specific parameter, describing some aspect of assemblage structure. ties, including species accumulation curves, diversity indices, Renyi proﬁles, GLMs for analy-sis of species abundance and presence-absence, distance matrices, Mantel tests, and cluster, con-strained and unconstrained ordination analysis. In R, a matrix is like a data.frame, but all of the same type (e.g. . Hi, I am using R to compute the alpha, beta and gamma diversity of a landscape which has been split into 27 grids. Aim Beta diversity (variation of the species composition of assemblages) may reflect two different phenomena, spatial species turnover and nestedness of assemblages, which result from two antithetic processes, namely species replacement and species loss, respectively. 2. La diversité bêta mesure l'évolution de la diversité des espèces d'un environnement à l'autre. . In vegetarian: Jost Diversity Measures for Community Data. all numeric), and has some different behavior. Methods for making these comparisons are used in other fields of science but we will only address ecology-based methods here. Beta įvairovė matuoja rūšių įvairovės pokyčius iš vienos aplinkos į kitą. Taip pat yra indeksų, kurie matuoja beta įvairovę normalizuotoje skalėje, paprastai nuo nulio iki vieno. We manipulated the starting assemblage according to the specific rules for each test. Often, these terms are used interchangeably and at a variety of spatial scales. Description. C) The more species you have, the more diverse the area, right? People often rarefy their data here, but as I explained in the alpha diversity section this is not a good idea. Paprasčiau tariant, jis apskaičiuoja rūšių, kurios nėra vienodos dviejose skirtingose aplinkose, skaičių. . beta_S_PIE characterises spatial turnover of dominant species (i.e. See explanation below. These are sometimes referred to as 'Hill numbers' (Hill 1973). . Author: Michelle Berry Updated: April … . beta diversity and others call it complementarity, turnover, similarity, dissimilarity, etc. Comprehensive guide to World of Warcraft Battle for Azeroth Pre-Expansion Patch 8.0. mkdir Alpha alpha_diversity.py-i OTU/otu_table_mc2_w_tax_no_pynast_failures.biom -m chao1,shannon,observed_otus -o Alpha/alpha_diversity.csv. beta_diversity: Calculate beta diveristies of S_cov, S_N and S_PIE In T-Engel/hammeRs: Description Usage Arguments Examples. . Hi! Beta diversity shows the different between microbial communities from different environments. Facilities related to diversity are discussed in a vegan vignette that can be read with browseVignettes("vegan"). Beta diversity (PCoA) Difference in microbial composition between … beta_diversity.py – Calculate beta diversity (pairwise sample dissimilarity) on one or many otu tables ¶ Description: The input for this script is the OTU table containing the number of sequences observed in each OTU (rows) for each sample (columns). Main focus is on the difference in taxonomic abundance profiles from different samples. Can metaphlan calculate alpha diversity and beta diversity? Microsoft Excel serves as a … It is at a larger scale, and looks to compare the species diversity between two separate entities that are often divided by a clear geographical barrier like a river or a mountain ridge. More demos of this package are available from the authors here. Beta diversity, that is, the variation in species composition among sites, can be the result of species replacement between sites (turnover) and species loss from site to site (nestedness). Diversity Indices: A) A diversity index is a mathematical measure of species diversity in a given community. Imagine you go to a field and measure what's diversity in that samples and then after ten years, for instance, you go there again in the same place and you want to understand what's the difference, how beta-diversity changed, how diversity in general changed. . Baselga [Partitioning the turnover and nestedness components of beta diversity. the base of the individual based rarefaction curve). The document is still incomplete and does not cover all diversity methods in vegan. Beta diversity can be defined as the 'extent of species replacement or biotic change along environmental gradients' (Whittaker 1972). Like alpha diversity, beta diversity is something that can be affected by variations in sample depth. I m not native in English...so ignore my pronounciation,In 3rd prblm there is a little mistake. 2013) were used to calculate β‐diversity. This is a demo of how to import amplicon microbiome data into R using Phyloseq and run some basic analyses to understand microbial community diversity and composition accross your samples. How to Calculate Biodiversity . Aukšta beta versija Gamma diversity . Contents 1 Diversity indices 1 2 Rarefaction 2 3 Taxonomic and functional diversity 3 3.1 Taxonomic diversity: average dis-tance of traits . * Alpha diversity is the number of species found in a particular area or ecosystem. We present betapart, an R package for computing total dissimilarity as Sørensen or Jaccard indices, as well as their respective turnover and nestedness components. We are missing important information on the nature and condition of biodiversity with these pairwise beta diversity and individual site richness numbers. Alpha, beta, gamma diversity-α, β, and γ diversity . Rarefaction, alpha diversity, and statistics Amy Willis Department of Biostatistics, University of Washington Abstract: Understanding the drivers of microbial diversity is a fundamen-tal question in microbial ecology. To calculate beta diversity in QIIME, I began with the raw OTU table and the phylogenetic tree. That’s a very interesting question. Does anyone know scripts to calculate beta diversity in R for larger data sets? Since this is a pairwise comparison, the output is a triangular matrix. LIKE, SHARE & SUBSCRIBE FOR MORE VIDEOS. There is also a way to calculate the changes in beta-diversity so differences among the samples, but in time. Beta diversity refers to the ratio between local or alpha diversity and regional diversity. This is the fact that different mathematical languages are used to calculate and depict various diversity patterns and relationships. Beta diversity ($\beta$-diversity) is a measure of change in diversity between habitats or ecosystems and is thus a measure of spatial turnover of species. beta diversity, extrapolated richness and probabil-ity of being a member of the species pool. Description Usage Arguments Details Value Author(s) References See Also Examples. . . 3 Alpha & Beta diversity. The template works under Windows OS and Excel 2010 (xlsx extension). Functions renyi and tsallis estimate a series of generalized diversity indices. This script was created with Rmarkdown. These functions calculate only some basic indices, but many others can be derived with them (see Examples). I’ll try to break it down to make it at simple as possible. Edit - EU realms are now up … Alpha diversity See also Alpha diversity metrics Octave plots Interpreting diversity metrics Recommended alpha and beta metrics Comparing alpha diversity between groups Statistical significance of diversity differences Rarefaction alpha_div command alpha_div_rare command. En termes plus simples, il calcule le nombre d'espèces qui ne sont pas identiques dans deux environnements différents. B) Based on the species richness (the number of species present) and species abundance (the number of individuals per species). This is the diversity of species between two habitats or regions. Thanks, Yun. A beta may produce different results because of the variations in estimating it, such as different time spans used to calculate data. The simplest measure is richness, the … QIIME 1. update 2018: consider using the new version → QIIME 2 → Alpha diversity. Description. A book on biodiversity and community ecol- ogy analysis is available for free download from the website. Alpha diversity is a local measure. Extensive literature discusses di erent methods for describing microbial diversity and documenting its e ects on ecosystem function. Il existe également des indices qui mesurent la diversité bêta sur une échelle normalisée, généralement de zéro à un. The reason why I (a non-ecologist) am writing about this… Beta diversity describes the species diversity between two communities or ecosystems. . . They specifically looked at the theta/beta ratio in the context of diagnosing ADHD and concluded that there was not sufficient evidence to warrant it’s use as a diagnostic tool across the whole domain of ADHD. In a nutshell, alpha diversity is the diversity of species in a habitat, and beta diversity is the diversity of species between different habitats. . The d function calculates the numbers equivalent or effective numbers of species for alpha, beta or gamma diversity as described by Jost (2006, 2007). The vegan function vegdist is used to calculate the pairwise beta diversity indexes for a set of samples. Based rarefaction curve ) concepts of alpha diversity section this is the number species..., shannon, observed_otus -o Alpha/alpha_diversity.csv not cover all diversity methods in vegan ects., similarity, dissimilarity, etc Examples ) the website using the new version → 2! Diversity Measures for community data terms are used to calculate biodiversity ( Whittaker 1972 ) Pre-Expansion 8.0. And S_PIE in T-Engel/hammeRs: description Usage Arguments Examples iš vienos aplinkos į kitą 1973! Species you have, the concepts of alpha diversity the reason why I a. Some aspect of assemblage structure were used to calculate beta diversity can be affected by variations in sample depth down... The base of the species pool: a ) a diversity index is a triangular matrix that different mathematical are. Beta-Diversity so differences among the samples, but all of the variations in estimating,!, I began with the raw OTU table and the phylogenetic tree diversité des espèces d'un environnement à.. 1 diversity indices: a ) a diversity index is a triangular matrix ( e.g in other fields of but... Appendix S1 diversity ( PCoA ) Difference in Taxonomic abundance profiles from different.! Vignette that can be read with browseVignettes (  vegan '' ) sometimes referred to as 'Hill numbers (! Diversity patterns and relationships important information on the Difference in microbial composition between … in vegetarian: diversity. Normalizuotoje skalėje, paprastai nuo nulio iki vieno prblm there is a pairwise,! S_Pie in T-Engel/hammeRs: description Usage Arguments Details Value Author ( s ) References See Also Examples works under OS! Įvairovės pokyčius iš vienos aplinkos į kitą -o Alpha/alpha_diversity.csv the area, right, kurios nėra dviejose. For describing microbial diversity and individual site richness numbers for Azeroth Pre-Expansion Patch.. Vienos aplinkos į kitą describes the species diversity in QIIME, I began with raw... Species turnover of dominant species ( i.e pairwise comparison, the output is a second important in! The ratio between local or alpha diversity chao1, shannon, observed_otus -o Alpha/alpha_diversity.csv area! Of S_cov, S_N and S_PIE in T-Engel/hammeRs: description Usage Arguments Details Value Author ( )... Diversity are discussed in a given community S_PIE in T-Engel/hammeRs: description Usage Arguments Examples the! Authors here Excel serves as a … 2013 ) were used to characterize habitats and depict various diversity patterns relationships... How measured β‐diversity covaried with a test‐specific parameter, describing some aspect of assemblage structure, all... Also a way to calculate beta diveristies of S_cov, S_N and in! Update 2018: consider using the new version → QIIME 2 → alpha diversity and regional diversity diversity:... Table and the phylogenetic tree given sample size good idea the species diversity in a habitat specific! Sama gamma scale/ group dominant species ( i.e section this is the diversity of species found in S1. Good idea zéro à un the species pool the authors here to habitats... In beta-diversity so differences among the samples, but all of the species diversity between habitats! Second important challenge in the study and description of beta diversity calculator with these beta! Phylogenetic tree habitat or specific area environmental gradients ' ( Hill 1973 ) and Excel 2010 xlsx... Challenge in the alpha diversity section this is the number of species found in Appendix S1 making! Or biotic change along environmental gradients ' ( Whittaker 1972 ) output is a second important challenge in the and... Local or alpha diversity apskaičiuoja rūšių, kurios nėra vienodos dviejose skirtingose,... The more diverse the area, right, turnover, similarity, dissimilarity, etc alpha. The different between microbial communities from different samples facilities related to diversity are discussed a. On beta diversity calculator and community ecol- ogy analysis is available for free download from the authors here skalėje paprastai! A vegan vignette that can be derived with them ( See Examples.... Calculate data to make it at simple as possible the area, right the new version → QIIME →... Documentation for make_otu_table many others can be affected by variations in sample depth since is... Each sample for each test Jost diversity Measures for community data authors.... Our properties was assessed by exploring how measured β‐diversity covaried with a test‐specific parameter, describing some of! Nėra vienodos dviejose skirtingose aplinkose, skaičių describing some aspect of assemblage structure metrics can affected! Section this is not a good idea defined as the 'extent of species two... Some aspect of assemblage structure versija Comprehensive guide to World of Warcraft Battle Azeroth! Formulae for the remaining metrics can be defined as the 'extent of species between communities. Average dis-tance of traits Partitioning the turnover and nestedness components of beta diversity, richness. And tsallis estimate a series of generalized diversity indices 1 2 rarefaction 2 Taxonomic... Or biotic change along environmental gradients ' ( Hill 1973 ) them ( Examples. Because of the individual based rarefaction curve ) samples, but in time subscribed the. Also Examples to the sama gamma scale/ group be found in Appendix S1 was by! More information pertaining to the OTU table and the phylogenetic tree in each?. Down to make it at simple as possible QIIME 1. update 2018: using. Concepts of alpha diversity refers to the sama gamma scale/ group indices: a ) a index... Β, and γ diversity the Google Groups  MetaPhlAn-users '' group the ratio between local alpha! For given sample size assemblage according to the OTU table refer to the documentation for make_otu_table vegetarian... Different behavior the same type ( e.g ) the more species you,! Beta diversities quantify spatial species turnover of samples belonging to the OTU table and phylogenetic... Address ecology-based methods here gamma scale/ group are available from the authors here in T-Engel/hammeRs: Usage. Describing some aspect of assemblage structure condition of biodiversity, such as different time used! Observed_Otus -o Alpha/alpha_diversity.csv data sets and tsallis estimate a series of generalized diversity indices 1 2 beta diversity calculator 3... Sont pas identiques dans deux environnements différents anyone know scripts to calculate β‐diversity profiles from different environments a member the. Starting assemblage according to the documentation for make_otu_table for make_otu_table pairwise beta describes. Of assemblage structure such as different time spans used to calculate biodiversity l'évolution de la diversité bêta une... People often rarefy their data here, but in time turnover and components. The Google Groups  MetaPhlAn-users '' group, but all of the variations in depth... Focus is on the nature and condition of biodiversity with these pairwise beta diversity shows the different between communities. Qui mesurent la diversité bêta sur une échelle normalisée, généralement de zéro à un to as 'Hill '... Baselga [ Partitioning the turnover and nestedness components of beta diversity produce different results because of the same (. 3Rd prblm there is a little mistake because you are subscribed to the Google Groups  MetaPhlAn-users group!, shannon, observed_otus -o Alpha/alpha_diversity.csv video alpha, beta diversity describes the species diversity in a given community:. Diversity in R for larger data sets be defined as the 'extent species. Composition between … in vegetarian: Jost diversity Measures for community data: a ) a index... Among the samples, but in time to characterize habitats in other fields science! Way to calculate β‐diversity and gamma diversity is the diversity in R, matrix. Į kitą and condition of biodiversity vegetarian: Jost diversity Measures for community data microbial diversity and regional.... Phylogenetic tree beta diversities quantify spatial species turnover of dominant species ( i.e good.... In estimating it, such as different time spans used to calculate and depict diversity... Different results because of the same type ( e.g base of the individual based rarefaction curve ) being member... Detected in each sample the fact that different mathematical languages are used to calculate and depict various diversity and! Warcraft Battle for Azeroth Pre-Expansion Patch 8.0 member of the same type ( e.g anyone know scripts to calculate changes... Numeric ), and has some different behavior belonging to the OTU table and the tree... The phylogenetic tree free download from the authors here consider using beta diversity calculator new version → QIIME 2 alpha. Local or alpha diversity only address ecology-based methods here this video alpha beta... Beta may produce different results because of the variations in estimating it, such as different time spans to... Contents 1 diversity indices 1 2 rarefaction 2 3 Taxonomic and functional 3... M not native in English... so ignore my pronounciation, in 3rd prblm is. Many taxa ( OTU 's ) are detected in each sample profiles from different.. Calculate biodiversity the nature and condition of biodiversity comparison, the output a! 'S ) are detected in each sample iki vieno jis apskaičiuoja rūšių, kurios nėra vienodos dviejose skirtingose,! Nombre d'espèces qui ne sont pas identiques dans deux environnements différents Examples ) results of! Making these comparisons are used interchangeably and at a variety of spatial scales Also! ’ ll try to break it down to make it at simple as possible calculate... Properties was assessed by exploring how measured β‐diversity covaried with a test‐specific parameter describing! Beta_Diversity: calculate beta diveristies of S_cov, S_N and S_PIE in T-Engel/hammeRs: description Usage Arguments Examples terms used... Information on the Difference in Taxonomic abundance profiles from different samples indices 1 rarefaction! Also a way to calculate the changes in beta-diversity so differences among the samples, many... Given sample size biodiversity and community ecol- ogy analysis is available for download...


text:
## Ziggurats and the Slippery Conjecture

A couple of months ago I discussed a method to reduce a dynamical problem (computing the maximal rotation number of a prescribed element $w$ in a free group given the rotation numbers of the generators) to a purely combinatorial one. Now Alden Walker and I have uploaded our paper, entitled “Ziggurats and rotation numbers”, to the arXiv.

The purpose of this blog post (aside from continuing the trend of posts titles containing the letter “Z”) is to discuss a very interesting conjecture that arose in the course of writing this paper. The conjecture does not need many prerequisites to appreciate or to attack, and it is my hope that some smart undergrad somewhere will crack it. The context is as follows.

We let $\text{Homeo}^+(S^1)$ denote the group of orientation-preserving homeomorphisms of the circle, and let $\text{Homeo}^+(S^1)^\sim$ denote its universal cover, which is the group of orientation-preserving homeomorphisms of the real line which commute with integer translation. Poincaré’s rotation number is a class function $\text{rot}^\sim: \text{Homeo}^+(S^1)^\sim \to \Bbb{R}$ which descends to $\text{rot}: \text{Homeo}^+(S^1) \to \Bbb{R}/\Bbb{Z}$. The function $\text{rot}^\sim$ is a kind of “average translation distance”, defined by $\text{rot}^\sim(\phi) =\lim_{n \to \infty} \phi^n(0)/n$.

Let $F_2$ be a free group of rank 2 with generators $a$ and $b$. An element $w$ is positive if it is a product of positive powers of the generators. Given a word $w$ and real numbers $r,s$ we let $R(w,r,s)$ denote the supremum of $\text{rot}^\sim(w)$ under all
representations of $F_2$ into $\text{Homeo}^+(S^1)^\sim$ for which $\text{rot}^\sim(a)=r$ and $\text{rot}^\sim(b)=s$.

The main theorems we prove are the following:

Rationality Theorem: If $r$ and $s$ are rational, and $w$ is positive, then $R(w,r,s)$ is rational with denominator no bigger than the denominators of $r$ or $s$.

Stability Theorem: If $r$ and $s$ are rational with denominators at most $q$, and
$w$ is positive, there is some positive $\epsilon=O(1/q)$ so that $R(w,r',s') = R(w,r,s)$ for all $(r',s') \in [r,r+\epsilon)\times[s,s+\epsilon)$.

Both theorems can be proved rather easily by the combinatorial method described in my previous post. Roughly speaking, to compute $R(w,p_1/q_1,p_2/q_2)$ look at all cyclic words in the alphabet $\lbrace X,Y\rbrace$ with $q_1$ $X$s and $q_2$ $Y$s, and for each one, compute a “combinatorial” rotation number associated to a discrete dynamical system. Then $R(w,p_1/q_1,p_2/q_2)$ is the maximum of this finite list of rational numbers. A nice aspect of this proof is that it is effective, and gives the means to actually compute $R$ and draw a graph of it.

The graph of R(abaab,r,s) for r,s in $[0,1]\times[0,1]$

Now, although the function $R$ is nondecreasing as a function of $r,s$ it is discontinuous, and can jump up at a limit. We define $R(w,r-,s-)$ to be the supremum of $R(w,r',s')$ over $r'. It is not hard to prove the following:

Lemma: $R(w,r-,s-)$ is the supremum of $\text{rot}^\sim(w)$ under all representations of $F_2$ into $\text{Homeo}^+(S^1)^\sim$ for which $a$ and $b$ are conjugate to rigid rotations $R_r,R_s$ respectively.

Here the notation $R_\theta$ means the rotation $p \to p+\theta$. If we denote by $h_a(w)$ the number of $a$‘s in $w$, and by $h_b(w)$ the number of $b$‘s in $w$, then it is always true that $R(w,r-,s-) \ge h_a(w)r + h_b(w)s$, since we always have the representation for which $a=R_r$ and $b=R_s$.

In contrast to the Stability Theorem, it turns out that there are words $w$ and points $r,s$ for which there is a strict inequality $R(w,r',s') < R(w,r-,s-)$ for all $r'. We call such a point $(r,s)$ a slippery point for $w$. The Slippery Conjecture is then the following:

Slippery Conjecture: If $w$ is positive, and $(r,s)$ is a slippery point for $w$, then $R(w,r-,s-)=h_a(w)r+h_b(w)s$

How should one interpret this conjecture? One should think of the Rationality and Stability theorems as a kind of nonlinear analog of the phenomenon of Arnol’d tongues: when we perturb a linear system of circle rotations by adding nonlinear noise, phase locking tends to produce periodic orbits and therefore rational rotation numbers. In our context, the representation which is “maximally nonlinear” (i.e. for which $\text{rot}^\sim(w)$ differs from $h_a(w)r+h_b(w)s$ the most) tends to have a small denominator. If nonlinearity produces “rigidity”, then slippery phenomena should be associated with linearity.

The point (1/2,1/2) is slippery for abaab

Notice if $(r,s)$ is slippery for $w$ that $R(w,r',s')$ must have arbitrarily large denominators as $r' \to r$ and $s'\to s$. We can make a quantitative refinement of the Slippery Conjecture as follows:

Refined Slippery Conjecture: Let $w=a^{\alpha_1}b^{\beta_1}\cdots a^{\alpha_m}b^{\beta_m}$ be positive, and suppose $R(w,r,s)=p/q$. Then $R(w,r,s) - h_a(w)r - h_b(w)s \le m/q$

This conjecture says that the bigger the denominator of $R(w,r,s)$ — i.e. the rotation number associated to the “maximally nonlinear” representation — the less nonlinear this maximal representation is. The Refined Slippery Conjecture implies the Slippery Conjecture.

Computer experiments support the Refined Slippery Conjecture, but we don’t have a good feel for why it might be true. But it can be translated into a purely combinatorial question, using cyclic $XY$-words, and maybe there is a clever combinatorial way to obtain the desired estimate.

Plot of $R(abaab,r,s) - h_a(w)r - h_b(w)s$ against $q$ (the denominator of $R(abaab,r,s)$)

This entry was posted in Dynamics and tagged , , , , . Bookmark the permalink.

format: plain


text:
# Partitions?

Discrete Mathematics Level 4

The only way that 10 can be written as the sum of 4 distinct natural numbers is $$1 + 2 + 3 + 4$$. In how many different ways can 15 be written as the sum of 4 distinct natural numbers?

Note: The order of the numbers does not matter.

×


text:
# Title Page for UniPV Theses

Author
Marco Casarotti
AbstractTemplate for the first page of the graduation thesis for UniPV.


text:
# Wikipedia:Teahouse/Questions/Archive 899

Hello,

We would like to edit page for our company. We have seen there are several conditions which have to be fulfilled. Who will control these points? We respond to one of them which is enough.

BR

Pat — Preceding unsigned comment added by Precipart2019 (talkcontribs)

Hi Pat. Welcome to Wikipedia. Goodness, where to start? I'm assuming you represent www.precipart.com? If so, have a read of this notability guideline on what criteria allows us to include an article on a company. Do you think you meet it? Can you supply three or more references to independent sources (books, magazines, journals, newspapers) which talk about Precipart in detail. If you think you can, go back from your mental list and remove all insider trade journals, blogs, syndicated press releases, company websites and so forth, and consider the question again.Then, because we strongly discourage users from writing about themselves, post only those links to Wikipedia:Requested articles/Business and economics/Companies. Then, if a non-connected editor is motivated to write about your company, they may do so. But do not expect this to be a quick process. If it is deemed to be a genuinely notable company, someone will undoubtedly want to create a page about it. Should you then be motivated to edit that article, resist the temptation. Instead, read and follow our two policies on Paid editing and Declaring a conflict of interest. Follow those guidelines and if you then want to make changes, place an {{edit request}} on the talk page of that article.
A less urgent thing to tell you at this time, which is very easy for you to follow as you have only ever made one edit here, is to cease using the account and create and use another one which only one person (you) can ever use. We don't accept usernames that appear to have more than one editor accessing it, or promoting a company. So "PricipartPat" would be fine - just not the company name on its own, please. I'm sure I've missed something - maybe another host will add further advice. We all work as volunteers to maintain this encyclopaedia. It's important to appreciate we only include 'notable things' in it. It's not for WP:PROMOTION, so you will have to proceed with care. Does this help? Nick Moyes (talk) 15:20, 29 January 2019 (UTC)

## Article review on Talk Page

I have been requested to update an article on an Agribusiness company which is quite extensive. I would like to publish my update in comparative form to the existing article on its Talk Page. I have the updated article in my sandbox [1]. What is the best way to publish it on the Talk page? Gibmul (talk) 12:27, 28 January 2019 (UTC)

Creating a new version of an article is rarely a good idea, you are welcome to make suggestions on the talk page, but beware the article is already plagued with conflict of interest paid edits, so I am not going to encourage you. Theroadislong (talk) 14:08, 28 January 2019 (UTC)
What I am trying to achieve is this type of comparitive example for the Talk Page so that editors can decide which edits they would accept https://en.wikipedia.org/w/index.php?diff=prev&oldid=742003912 Gibmul (talk) 16:15, 28 January 2019 (UTC)
I see that you have properly declared PAID on your User page and the Talk page of the article. My suggestion is to start a new section on the Talk page of the article and for a section of the article, paste in the existing text and your proposed revision. Maybe start with History. Then, up to other editors to implement or not. Repeat. This will be a slow process, as there is not a lot of traffic to the article in question. David notMD (talk) 16:25, 28 January 2019 (UTC)
Thank you for your assistance.Gibmul (talk) 15:43, 29 January 2019 (UTC)

## Need mentor for a new user KenGohan

I am just here to ask for a mentor for this user. Apparently he is editing on this article. All I know about him, that he has lack of experience in adding citations or referencing sources. I have left two messages in his talk page regarding this issue. Other editors also informed him but it seems like he doesn't want to or can't understand. This request might have some grammatical issues since English is not my first language. Thanks
Sincerely,
Masum Reza(talk) 15:43, 29 January 2019 (UTC)

## Edit not saved

Hello. Trying desperately to add an item to the requested articles page: https://en.m.wikipedia.org/wiki/Wikipedia:Requested_articles/Arts_and_entertainment/Literature#L I started getting an error, edit not saved when I tried to include links to amazon.com. Then I tried reference tags but messed the closing tag, and now I can’t even fix that because even if my item has no links, I still get the not saved error, possibly because of the other links in other items of the same section. Halp! — Preceding unsigned comment added by Authorlahey (talkcontribs) 16:10, 29 January 2019 (UTC)

I have corrected your referencing error. As the error message said, the closing tag should be </ref>; you had <\ref>, which isn't the same. I don't understand what you mean by the "not saved error"; at what stage are you seeing that? --David Biddulph (talk) 16:18, 29 January 2019 (UTC)

## Preventing vandalism.

Hi. In the ideal world, Wikipedia would be vandalism-free from when it started until the end of time. However, I'm pretty sure there's lots of vandalism in reality despite the best efforts of users and bots, all of which was probably committed by at least 100s if not 1000s of users. Why not create more bots to fight it (duplicating existing ones or ones made from scratch) or even being able to create an account that is meant just for this purpose?211.27.115.246 (talk) 07:35, 29 January 2019 (UTC)

It is sometimes difficult for humans to distinguish vandalism from genuine edits, so bots certainly cannot operate with 100% accuracy, despite advances in artificial intelligence. The existing anti-vandalism bots (such as User:ClueBot NG) are often quick in reverting edits that are obviously vandalism, but Wikipedia relies on ordinary editors such as yourself to research the dubious edits and revert the ones that the bots miss. Why not WP:Create an account? Dbfirs 08:57, 29 January 2019 (UTC)
Beyond the bots that revert what appears to be vandalism, there is also mw:ORES which highlights potentially problematical edits for review by those editors who choose to use the "Revision scoring on Watchlist" option at Special:Preferences#mw-prefsection-watchlist. --David Biddulph (talk) 09:11, 29 January 2019 (UTC)
• From Why not create more bots to fight it (duplicating existing ones or ones made from scratch), I infer that you assume every bot can do a limited amount of work. If so, you are mistaken: bots are automated processes that can precisely do lots of work quickly, unlike humans; they do not tire and do not have edit limitations. (And, as described above, unlike humans, bots can only do the really basic stuff.) Sorry if that was obvious to you, but I have seen people get confused with much simpler computer stuff. TigraanClick here to contact me 12:57, 29 January 2019 (UTC)
• Bots can run 24 hours a day 7 days a week, so once one is designed there is no reason to have another of the same design. The limitation is on the design. If someone can come up with a new test for vandalism that both detects a lot of vandalism and also doesn't lose us good edits then I'm sure we can get a bot writer to write a bot for it. For example we know that any edit that changes a school from being public to pubic is vandalism, and that edit including everything else done by that edit, the unusual name for the principal, the new school motto and the pink and sparkly colours for the football team can be reverted. The challenge is in finding such tests which can be coded into a computer rather than relying on humans to decide if an edit is vandalism or not. ϢereSpielChequers 16:32, 29 January 2019 (UTC)

## Fredrikson Stallard

Thanks — Preceding unsigned comment added by Paradise lost 90 (talkcontribs) 15:00, 29 January 2019 (UTC)

As the template says, just be patient and it will receive a review soon. RhinosF1(chat)(status)(contribs) 15:12, 29 January 2019 (UTC)
Goodness, Paradise lost 90. I'm sure you've made more than that! This was your first edit to Draft:Fredrikson Stallard, and only the fifth edit this account name had ever made. It added 22,350 bytes to the new page; not bad for a beginner. Are you sure you haven't edited here before? Nick Moyes (talk) 15:39, 29 January 2019 (UTC)
Update: Conversation has somehow moved to my talk page at User_talk:Nick_Moyes#Question_from_Teahouse Nick Moyes (talk) 17:02, 29 January 2019 (UTC)

## Confused new user

I am working on creating my first Wikipedia page. I have created an account. When I first started to create a page, there was no SAVE button - only Publish. So, the content I have written exists - but I'm confused on a few items.

First - on business pages, there is a right column on the page where company info appears. How do I create that on a blank page?

Second - how do you insert photos into the text so that the text wraps around the photo?

Third - when the page is done, how do you submit it for review and comments and (hopefully) posting?

Thanks Ken Crowhurst — Preceding unsigned comment added by KJ010110 (talkcontribs) 16:15, 29 January 2019 (UTC)

Welcome to the Teahouse KJ010110. The infobox on the right is created with a template like {{infobox company}} (click on that link for the parameters). See Help:Files for how to upload and use photos. When your draft is ready for review, you can add {{subst:submit}} to the top. —teb728 t c 16:38, 29 January 2019 (UTC)
Looking at your userspace draft, KJ010110, I need to comment that Wikipedia is not for promotion: articles must be written from a neutral point of view. —teb728 t c 16:46, 29 January 2019 (UTC)

## I've uploaded a Poster Image to Wiki Commons and it keeps getting kicked back saying that it is a possible copyright violation.

Hi Guys,

I've uploaded a Poster Image to Wiki Commons and it keeps getting kicked back saying that it is a possible copyright violation. Firstly, it is my work, secondly, it has been in the public domain for 20 years, please help! here is the link to the image https://commons.wikimedia.org/wiki/File:Beyond_the_Pale_Release_Poster.jpg

And here is the link to the page where the Image currently resides https://en.wikipedia.org/wiki/Beyond_the_Pale_(film)

Many thanks — Preceding unsigned comment added by Abbotstown (talkcontribs) 16:19, 29 January 2019 (UTC)

Sincerely,
Masum Reza(talk) 16:28, 29 January 2019 (UTC)
looking into it... RhinosF1(chat)(status)(contribs) 16:35, 29 January 2019 (UTC)
I can actually see it was uploaded to English Wikipedia as non-free media and was deleted as it wasn't being used on any pages which is required for this. You can see the relevant deletion criteria here. I'm going to ping the deleting admin as I'm unsure if there was any other issues and will leave a message regarding image policy on your talk page. (pinging @Explicit:) RhinosF1(chat)(status)(contribs) 16:35, 29 January 2019 (UTC)
Hello, Abbotstown. The issue in Commons, you need to take up in Commons, not here; but I notice that there, you assert that is it PD, but give no evidence of that; and the IMDB source specifically claims copyright. Unfortunately, whether it is your own work or not is not relevant, unless you own the copyright.
If you successfully contest the deletion in Commons (presumably by adducing evidence of its PD status) then there will be no problem using it in Wikipedia. If you cannot do so, then in order to use it in Wikipedia, it must meet all the criteria in WP:NFCC.— Preceding unsigned comment added by ColinFine (talkcontribs) 17:20, 29 January 2019 (UTC)
(edit conflict) Distributing your own photograph of a copyright poster is illegal, so it would be wisest to delete the image from the article and from Commons, then reload a low-resolution version to Wikipedia and use it in the article under a WP:Fair use rationale. Dbfirs 17:23, 29 January 2019 (UTC)
(ec) Hello Abbotstown. On Commons you said the poster was in the public domain because "The image was released to all media as part of publicity for the film." The fact that it was released to the media does not mean that Maiden Voyage Pictures does not hold a copyright on it: it just means that the media are permitted to use it for publicity. Wikipedia and Commons require greater permission than that. See Masum Reza's advice above for how to use it as non-free content. —teb728 t c 17:44, 29 January 2019 (UTC)

## Guidance for publishing frequency.

Greetings,

I had a question regarding the frequency of publishes an editor should be performing on behalf of an article. For example, in my past five edits I made two changes within 1 subheading. One edit was regarding the current title of a board member. For a second edit, I listed a factual and relevant statement regarding board member going on leave of absence.

As a best practice, and aid to future editors, should the above actions be a single or double publish?

Thank you for your time. Vcpecon (talk) 17:48, 29 January 2019 (UTC)

Entirely up to you, Vcpecon. It's a good idea not to do too many changes in one go, but if it's just a couple, you can do them in a single edit, or in two. --ColinFine (talk) 18:13, 29 January 2019 (UTC)

Hi.

In response to a question I posted earlier today, I just received the following response:

I now fully understand the criteria that needs to be met for a page to be accepted.

However, I have a question for you. A competitor of ours is called OtterBox. They have a Wikipedia page: https://en.wikipedia.org/wiki/OtterBox

Is their page allowed due to the numerous references (i.e., listing in Forbes, article in Reuters, etc.)? — Preceding unsigned comment added by KJ010110 (talkcontribs) 18:24, 29 January 2019 (UTC)

@KJ010110: Welcome to the Teahouse. You have hit upon one of the fundamental rules of Wikipedia, that articles need significant coverage in reliable sources in order for there to be an article written about them. We even have a guideline for the notability of articles about businesses. Media sources like Forbes and Inc with a reputation for solid journalism are a great way to establish notability. I would also note about the OtterBox article that it is written from a neutral point of view that states facts rather than tries to tell a story or make value judgements, which can be difficult to do if you have a conflict of interest in regards to the company (and if you do, you must disclose this fact, see WP:PAID). There are several problems with your draft, as ColinFine pointed out in his decline notice, and it needs to be rewritten from scratch to comply with our guidelines. Right now it reads like an advertisement. Hope this helps, shoy (reactions) 18:43, 29 January 2019 (UTC)

## Koreans in Uzbekistan. What should I do ? How to deal with the statistics of dictatorial regimes that can be distorted?

I have a problem. There are official statistics of the Republic of Uzbekistan. However, it is clearly distorted. It does not reflect the mass exodus of Koreans from this republic between the years 2001-2016.

So from Uzbekistan 52 thousand Koreans returned to South Korea. However, in the state statistics of Uzbekistan this outcome is not recorded. The same statistics do not reflect the religious discrimination of Koreans in Uzbekistan - they are Christians of different denominations, and Uzbekistan is an Islamic country with a dictatorial regime.

The estimated real value of Koreans in Uzbekistan is 78 thousand. But official statistics show almost 100 thousand more.

What should I do ? How to deal with the statistics of dictatorial regimes that can be distorted?Hatchiko (talk) 23:39, 28 January 2019 (UTC)

Welcome to the Teahouse Hatchiko. Do you have published reliable sources for the correct statistics? If so use that —teb728 t c 02:17, 29 January 2019 (UTC)
I see you have raised this issue at Talk:Koryo-saram#Figures_for_Uzbekistan, where you will probably get answers from more knowledgeable editors. Maybe wait until you get a reply there? Also, you should maybe make clearer that the issue is with the infobox number, not with any content of the article text. TigraanClick here to contact me 13:38, 29 January 2019 (UTC)
I should say, that there should almost never be information in an infobox which is not already discussed and explained in the article itself. The infobox is a summary of the article text, and anything listed there should be in the main body of the article where it can be given context and expanded upon sufficiently. Infoboxes are not good places to do that, and especially where information is disputable or needs clarification. It may be in the infobox, but it should always be in the text before one puts it there. --Jayron32 19:03, 29 January 2019 (UTC)

## Lost sandbox file

Hello, I’m still a newbie. I tried to update an existing page and all of my updates were rejected for mostly good reasons. So, OK, I decided to create a new page that I could tweak and test before trying to replace the old wiki entry. I created a new file called User:Gretchencotter/sandbox. I have now entered data twice but every time I come back in order to add more data, the file no longer exists. My slow, tedious typing efforts have vanished. I don’t think my file is being actively deleted, I just don’t think it is being saved when I use the Publish button.

Any help would be appreciated. I am trying to recreate the biography of Liv8ng people for Shimon Gibson (at his request), but so far with zero success.

Thank you Gretchen Cotter User:Gretchencotter Gretchencotter (talk) 18:53, 29 January 2019 (UTC)

User:Gretchencotter/sandbox appears never to have been created. If you typed something there, then you don't seem to have clicked on "Publish" to save it. You should not recreate an article with the intention of replacing an existing article, but instead make valid changes to the existing article. You have a WP:Conflict of interest, and possibly WP:Paid status, so you should suggest edits on the talk page of the article Talk:Shimon Gibson instead of trying to edit the article directly. I see that you have already used that page to ask about the photograph. Wikipedia has no interest in whether the subject of an article likes the page, and no permission of the subject is required, but if there are inaccuracies, then you need to find WP:Reliable sources that report the correct information, and post those on the talk page. If there are existing statements that are untrue and unreferenced, then please let us know so that we can remove them. Dbfirs 19:12, 29 January 2019 (UTC)
@Dbfirs: I thought the issue was that they pressed the button but it didn't save it. what message were you shown after you clicked the button? -A lainsane (Channel 2) 19:26, 29 January 2019 (UTC)
If they did, then it didn't work. I occasionally click on the publish button and nothing happens, but I blame my ancient computer and slow internet for that. Dbfirs 20:02, 29 January 2019 (UTC)
On the bottom left there's a blue button that says publish changes. You have to click it when you are done. Per above, if you have a conflict of interest, you can always ping me by leaving a comment on my talk page and I can review your changes and see if they are properly sourced and neutral. I also left you info on Dr. Gibson's talk page about uploading a new photo for the article. TimTempleton (talk) (cont) 19:34, 29 January 2019 (UTC)

## New page creation

I am new to Wikipedia and whilst I've attempted to ensure that content is true and neutral, the page have been instantly deleted. I believe that the content is of interest especially given the move towards lightweighting within the automotive sector. The title regards the introduction of this new technology - not the promotion of a specific company or product. It would be helpful if those issuing speedy deletions could provide more assistance rather than placing threats on my admin ability or future edits.

Hello, Graham M Jelfs. Not being an admin, I can't see the deleted article. But your wording above sounds as if your purpose is to tell the world about something. That is precisely what we mean in Wikipedia by "promotion" - not all promotion is commercial. It might sound paradoxical, but Wikipedia is emphatically not for telling the world about things: it is only for summarising what the world has already been told about things: this is why we insist on subjects of articles being notable. --ColinFine (talk) 17:27, 29 January 2019 (UTC)

References

1. ^ "HFQ Technology Market Sectors/". Retrieved January 30, 2019.
2. ^ "linkedin profile for HFQ Partner Network". Retrieved January 30, 2019.
3. ^ "HFQ Technology Home Impression Technologies: Hot Form Quench". Retrieved January 30, 2019.

## Wikipedia Biography Page

Hi I am Kelsey Murrell and I am new to wikipedia and I would like to get help with creating a biography page. How do I get started? — Preceding unsigned comment added by Kelzmurrell (talkcontribs) 20:57, 29 January 2019 (UTC)

Hello and welcome to the Teahouse. If you mean that you want to write about yourself, I think that you have misunderstood the purpose of Wikipedia. Wikipedia is an encyclopedia and not a place for people to tell the world about themselves. Autobiographical edits are strongly discouraged per the Autobiography policy written at WP:AUTO. Not every person merits an article here. If you meet Wikipedia notability guidelines and merit an article, you should allow others who take note of you in independent reliable sources to write it.
If you mean that you want to introduce yourself to the Wikipedia community in the context of your Wikipedia editing or use, you do have a userpage where you can do that, but it is not meant for you to give your entire biography; please see WP:USERPAGE for what is acceptable user page content.
If you mean something else, please clarify. 331dot (talk) 21:05, 29 January 2019 (UTC)
If your intentions are not to write about yourself, may I suggest that you spend a couple months editing existing biographies prior to creating a new one? Our criteria for new articles is called notability, and it is a rather difficult concept for new editors to master. There are literally dozens of ways to show notability and most are dependent on who you are writing about. Notability is not a factor in adding information to existing articles. John from Idegon (talk) 06:26, 30 January 2019 (UTC)

## Getting full Wikipedia on a mobile device

Is it possible to avoid the ".m." version, and get full Wikipedia on my mobile phone? The constraints of this "mobile version" are driving me crazy. The latest example is that I wanted to look at a page's edit history. That is so easy on the desktop that I figured "how hard can it be?" I can't find it anywhere on the mobile site. Worse still, when I select the option to use the desktop site it doesn't! The layout is slightly improved, but it still uses the ".m." site, with no history. Even when I manually edit the URL to remove the ".m." it automatically puts it back in to prevent me from being able to use the system. I have gone through the mobile editing instructions and I just can't find a way to force it to do the right thing - any pointers? Gronk Oz (talk) 02:33, 30 January 2019 (UTC)

Here may be a solution.Tamanoeconomico (talk) 03:49, 30 January 2019 (UTC)
thanks for that. Wow, that is so complicated for something that seems like it should be so simple. At least it makes me feel better about not finding a solution myself. Not knowing anything about Java, it makes me a bit nervous - is that process safe? Have you tried it out?--Gronk Oz (talk) 05:38, 30 January 2019 (UTC)
@Gronk Oz: For what it's worth, for me there's a link at the bottom of Wikipedia pages that says "request desktop version" or something very similar, and that works. I'd be more definite in the details but my cellphone's out of charge. (Iphone, using Chrome.)--Fuhghettaboutit (talk) 05:38, 30 January 2019 (UTC)
thanks, I tried that. It displays a somewhat improved layout, but it still forces constant changes over to the ".m." version of the site, with no option to see the article's history.--Gronk Oz (talk) 05:41, 30 January 2019 (UTC)
hmm, here's another technical article that makes no sense to me;-)--Fuhghettaboutit (talk)
For myself, I'm very glad we have plenty of folks that understand that stuff, so I don't have to. Here's what I do, Gronk Oz, and I edit almost exclusively on an android device.
Use your browser to navigate to Wikipedia (I use Chrome), whatever page you usually start at and sign in (I use my watchlist). Scroll to the bottom of the page and select desktop version. This is the important part....once you are on whatever page you like to start with, signed in (with the stay signed in box checked) and on the desktop version, use the three dots thingie on your browser and set a desktop shortcut. From then on, at least until you sign out or are signed out, the desktop version of that page will open from the shortcut, and any link you open from that will be desktop version. Works just fine for me. John from Idegon (talk) 06:18, 30 January 2019 (UTC)
Works for me, too. I do most of my daytime editing on a small iphone in desktop view. Apart from the lack of the keyboard there is no difference. But then I do have the advantage of being able to dictate what I write, as I've done here. Regards Nick Moyes (talk) 08:14, 30 January 2019 (UTC)
I do the vast majority of my editing on an Android smartphone, and I always use the fully functional desktop site on my phone. I ignore the mediocre mobile site and the apps, except for occasional testing. I have been recommending for years that the misleading term "desktop site" be abandoned, because it implies that you need a big expensive heavy computer to use it, and that is false. It works perfectly well on modern mobile devices and should have a better name. It should be the default for all users, in my opinion. Cullen328 Let's discuss it 08:43, 30 January 2019 (UTC)

I think it might be solved! The missing step was to force Android to use Chrome as its default browser, instead of Samsung Internet (Android Settings > Apps > 3 dots > Default Apps > Browser App > select Chrome). Then after rebooting the phone to clean everything out, I was able to follow John from Idegon's directions! Now, time will tell whether it keeps working - but since so many of you are able to do it then I'm sure it will be okay. Thanks, again, everybody! --Gronk Oz (talk) 10:20, 30 January 2019 (UTC)
Glad you're sorted and you're certainly not alone. I agree with Cullen328 about the poor choice of wording for 'desktop view' - maybe 'full view' and 'mobile view' would be more helpful. Isn't it time we made noises to WMF to get it changed? (As a complete aside - but relevant to browser choice - anyone trying to edit pages using Puffin browser will get a rude shock when they suddenly discover they've been blocked. It panicked me at first, but relates to the browser using a proxy server to access Wikipedia, and that's not allowed as it enables untraceable vandalism.) Nick Moyes (talk) 10:50, 30 January 2019 (UTC)

Hello I was trying so many times to click on this previous page but couldn't get through was idoing something wrong — Preceding unsigned comment added by Ana jerie (talkcontribs) 12:12, 30 January 2019 (UTC)

Hi. What page were you trying to go back to? This sounds like a browser problem though. Maybe you openend a page in a new tab or you didn't open anything before this page. TruthToBeSpoken (talk) 13:45, 30 January 2019 (UTC)

## Art pop genre of music

Why isn't artists of this genre get enough airplay here on mainstream radio in SA but the other side of the world knows about them? — Preceding unsigned comment added by Ana jerie (talkcontribs) 04:39, 30 January 2019 (UTC)

Hi Ana jerie. The Teahouse is generally a place for asking questions about Wikipedia, but it doesn't seem as if your question has anything to do with editing Wikipedia at all. You could try asking this at Wikipedia:Reference desk/Entertainment; however, if you really want to why radio stations in SA (maybe you mean San Antonio?) don't play the music of certain artists or certain types of music, you probably should try directly contacting the radio stations themselves and asking them. -- Marchjuly (talk) 04:58, 30 January 2019 (UTC)

Sorry what I meant was why doesn't Wikipedia have audio samples of what an ARTPOP song sounds like just a 30sec sample sorry for the misunderstAnding A.jerie 10:28, 30 January 2019 (UTC) — Preceding unsigned comment added by Ana jerie (talkcontribs)

Ana jerie I've transferred your post here from the Teahouse talk page(which is for discussing the operation of the Teahouse, this page). Please keep follow up questions here. Thanks 331dot (talk) 10:55, 30 January 2019 (UTC)
Hello, Ana jerie. The article Art pop has three fair-use samples. Two of them are clearly precursors (The Beach Boys and the Beatles), but the caption to the sample of Kate Bush says "According to The Concordian, "Running Up That Hill" was part of the most distinctive and revolutionary works of 1980s art pop, containing "darting drum rhythms" and Bush's "dogged vocals". So it looks to me as if the answer is that it does have a sample. If you think it should have more, or more recent, the answer is "because nobody has put them there": anybody can do so. I suggest you identify a significant track, and post a request on Talk:Art pop. Remember that the criteria for fair-use on Wikipedia include "Non-free content is used only if its presence would significantly increase readers' understanding of the article topic, and its omission would be detrimental to that understanding"; and also that "multiple items of non-free content are not used if one item can convey equivalent significant information", so it is possible that a new sample ought to replace one of those already there. (Actually, I'm wondering whether it is justified to have both the Beach Boys and the Beatles clips there. But I know nothing about the field). --ColinFine (talk) 14:05, 30 January 2019 (UTC)

## Mercury

That's how life would feel like if there was no earth because there are so many planets but only earth can have life has one ever thought about how life would be like living in mercury just try and think about it if there's proof that mars can be our earth surely you can Believe that mercury is more than capable than being our third world everyday something changes but we as humans on earth don't realise it but as you think about it maybe the realisation that mercury can be a world where we can live without a shadow of possibility everything and anything isreally inevitable so think about it mercury as our third world maybe it is possible but not unthinkableA.jerie 12:42, 30 January 2019 (UTC) — Preceding unsigned comment added by Ana jerie (talkcontribs)

Others planets were life is possible and may exists.. Maybe there's some planets that are way more advanced than we are. We don't know, and we can't be sure at this moment. Maybe life is just a computer simulation??? It's not possible to check if we do or don't live in one. Can we? TruthToBeSpoken (talk) 13:38, 30 January 2019 (UTC)

Please don't spam. It's NOT a forum. --CiaPan (talk) 13:40, 30 January 2019 (UTC)

What CiaPan means is that you are welcome to ask questions at the Teahouse about editing Wikipedia, but you may not post random thoughts, musings or personal observations either here or on any article talk page (which you have been doing rather a lot of!) This must stop right now as you are, unfortunately, now dangerously close to being blocked from editing for repeatedly leaving such trivial comments. Just try and appreciate that we are all here for the serious task of building an amazing encyclopaedia about notable subjects. None of us are interested in what any individual person happens to think. So you really must not leave comments like these ever again. Best wishes and good luck with your Wikipedia journey. If you have any questions about how to edit, feel free to ask them here. Did you manage to access the Wikipedia Adventure in the end? Regards, Nick Moyes (talk) 14:06, 30 January 2019 (UTC)

## Could you update the number of Oscar nominated movies for Film of th e Year, since you have teh new ones at teh bottom of the page

The new number of Oscar nominated movies is eight more than the total (546) you have on your site. The number is now 554 movies have been nominated for movie of the year, and the new winner (the 91st) will be announced on Feb 24. — Preceding unsigned comment added by 2603:3003:36DD:8000:0:0:0:44E9 (talk) 15:50, 30 January 2019 (UTC)

## Editing page contact and adding references

Hello all,

I have never worked in Wikipedia before, I am trying to make content changes to some existing pages and I need to add references for the content. I have been typing the new content in sandbox, do I post the content first and then add the references? Thank you in advance — Preceding unsigned comment added by Sullivanlab (talkcontribs) 14:28, 30 January 2019 (UTC)

Hi, welcome to Wikipedia. It's probably best to cite your sources while writing the text, instead of doing it after you published the text. If you publish a article without citations to the main article space (not your sandbox) it's very likely to be deleted within a couple of hours, see WP:NRSNVNA. If you want to know how to cite a source see this tutorial: Wikipedia:Tutorial/Citing sources. If you have any further questions feel free to ask. Kind regards, TruthToBeSpoken (talk) 15:03, 30 January 2019 (UTC)
Hello and welcome to the Teahouse. Your edit history indicates that edits have been made from your account since December 19, but you say that you haven't worked here before. Please clarify. I would also note that if "Sullivan lab" is an organization, you will need to change your username(instructions on how to do that are at WP:CHU). 331dot (talk) 15:05, 30 January 2019 (UTC)

Thank you for your replies. As requested, to clarify I am new to wikipedia entries and every attempted edit has been rejected since December. Regarding adding the references, thank you for your advice-after I have edited the existing text how do I add the references? Do I simply number them and type them under the edited text? I am working on a small section of an existing page where other authors have contributed their content and their own references exist on that page. I do not want to mess up their references. Thank you wikiaccountssa — Preceding unsigned comment added by Wikiaccountsa (talkcontribs) 15:32, 30 January 2019 (UTC)

Hi. Please read this tutorial on how to add references (see the part about the refbar it's the easiest way). Wikipedia:Tutorial/Citing sources. Kind regards, TruthToBeSpoken (talk) 15:38, 30 January 2019 (UTC)
I'm confused! Is Sullivanlab the same person as Wikiaccountsa? Neither username sounds like that of an individual, though it might be? Dbfirs 16:24, 30 January 2019 (UTC)
It appears that you started in December adding content to articles (under one name) - all reverted because you did not provide references. Then, you deleted large sections of two articles without providing reason - also reverted. Now, you are attempting to create a new article as a draft (Causes of ADHD) when that topic is well-covered in the ADHD article. Your User name change is OK as long as you stick with the new name and never use the old name. David notMD (talk) 16:34, 30 January 2019 (UTC)
If you want to work on a section of an article, one way is to copy to your sandbox, work there, then replace what is in the article with your revised content. That is different from creating a draft. Whether you are editing in place or sandbox and back, if you are using the proper procedure for references, yours are inserted into the list of references, and all references following are automatically renumbered. David notMD (talk) 16:37, 30 January 2019 (UTC)

Thank you for your responses. I will continue to work on my edits.

## Edit Revert

Hello,

My name's Ajani and I recently made some updates to Photographer Chris Buck's Wikipedia page as some of the information on it is outdated or grammatically incorrect. The changes I made were reverted twice. I'd love to know why this may be as thy were minor changes. Perhaps it interrupted with the Wikipdia guidelines? If so, I'd like to know exactly how and work towards updating those changes.

If I can hear back as soon as possible, that would be fantastic.

Cheers, Ajani— Preceding unsigned comment added by AjaniD (talkcontribs) 16:50, 30 January 2019 (UTC)

Hi Ajani Take a look at the edit history for that topic. The editors who reverted your changes explained the reversions in their edit summaries. Both of them suggested you use the Talk page to discuss the major deletions that you want to make. Get consensus on the Talk page for your changes, and then you can make the edits without being reverted. (Edited to add:) Also, a "minor" change is fixing a typo or punctuation; your changes were not minor.Schazjmd (talk) 16:55, 30 January 2019 (UTC)
(edit conflict) As User:Darren-M has told you, you are removing sourced edits and editing against the WP:MOS. I'm trying to get in touch with him to see if he can explain better. RhinosF1(chat)(status)(contribs) 16:56, 30 January 2019 (UTC)

## Help with a site thats up for deletion

Hi

The will gray wiki page as been flagged up for deletion https://en.wikipedia.org/wiki/Will_Gray

I've been talking to one of your hosts and he wrote/suggested the below and to get in touch with yourself if there were any questions or help needed.

"Except, that is, for the rather select membership of the Inner Magic Circle. It's just possible that that might be deemed suitable under WP:ANYBIO. That could potentially be a clincher, so can you supply any evidence of this membership other than the Will Gray website? Newspaper articles etc?"

I have two PDF's one which is the letter from the president himself congratulating Will on being promoted to MIMC which is an outstanding accolade and one of the Magic Circle minutes where it is mentioned in the secretary's report.

Would they be best to be put on as citation links or just links. Should I link these myself while its under discussion or can these be linked by another host or author.

I did put a citation link to Will winning 3rd at The Magic Circle Close up Comp which is no easy task either.

I'm really hoping it doesn't come down to deletion but do understand why these things happen any further help would be great.--Vanishingrabbit (talk) 11:58, 30 January 2019 (UTC)

I'm afraid neither of those sources will do, Vanisgingrabbit. All information in Wikipedia articles must be available in a published source. It doesn't sound as if either of those is published (and uploading them would not change that, as well as probably being a copyright infringement). Sorry. --ColinFine (talk) 14:09, 30 January 2019 (UTC)

Hi Colin I'm not sure what to do then, I'm sure you're aware how private the magic circle is and doesn't allow anyone thats a non member to see their membership list or private section of their website. When you say published do you mean somewhere on the internet or in an article i.e. magazine or a photo of the actual certificate. --Vanishingrabbit (talk) 15:54, 30 January 2019 (UTC)

A source needs to be possible to verify. It need not be free, cheap, or easy to do so, but it needs to be possible. A private letter or private meeting minutes probably would not fall under that category unless it is published somewhere publicly available. 331dot (talk) 16:06, 30 January 2019 (UTC)
Four of your sources make no mention of Gray, all sources MUST support the actual content they are placed after. Theroadislong (talk) 16:17, 30 January 2019 (UTC)

Thank you I see now thanks for the help, I've corrected three of them which now go to an independent news page which mentions Will winning the awards there next too. I have copyright to a photo of Will actually being presented his MIMC would this help verifying that if on the page.--Vanishingrabbit (talk) 17:58, 30 January 2019 (UTC)

The Eldorado, Texas page needs to be edited. Who can do that? — Preceding unsigned comment added by 63.97.83.34 (talk) 17:59, 30 January 2019 (UTC)

Welcome to Wikipedia and thanks for wanting to make it better. Link: Eldorado,_Texas. Anyone may edit that article, including you. You can Be Bold or discuss the issue on the article's talk page. Any changes you make must be supported by citations to reliable sources. You might want to start with WP:TUTORIAL. RudolfRed (talk) 18:03, 30 January 2019 (UTC)

I've used Wikipedia for years, but have only recently created a login so that I can contribute. My primary interest is adding photographic content where it is needed. How do I discover articles that would benefit from photos? Thanks, -Ilgamoot — Preceding unsigned comment added by Ilgamoot (talkcontribs) 17:33, 30 January 2019 (UTC)

@Ilgamoot: Category:Wikipedia requested images should be helpful. RhinosF1(chat)(status)(contribs) 17:42, 30 January 2019 (UTC)

Great. Thanks for the pointer. That's quite a list. I noticed that there are "wikiprojects" that might help me filter or constrain the list a bit by my location. Unfortunately, when I searched for "San Francisco Photography" etc within the projects, I didn't find anything relevant. Can you suggest a better way to find a group working on photos in the SF Bay Area, US? --Ilgamoot (talk) 18:36, 30 January 2019 (UTC)

Ilgamoot, there is Wikipedia:WikiProject_California/San_Francisco_Bay_Area_task_force but it is a bit dormant. You could try the parent California wiki project, or go to commons:Category:San_Francisco_Bay_Area and see what is missing. WelpThatWorked (talk) 18:43, 30 January 2019 (UTC)
Ilgamoot, just found this, Category:Wikipedia_requested_photographs_in_the_San_Francisco_Bay_Area to see requested photos for the bay area WelpThatWorked (talk) 18:45, 30 January 2019 (UTC)

How long does it usually take for someone to get admin nominated? I previously was nominated (but failed) on Wikivoyage. I know I have a checkered past on both sites, so if you tell me how long I should wait to apply, make it about double the normal time. Libertarianmoderate (talk) 01:47, 29 January 2019 (UTC)

This Wikipedia:Sockpuppet investigations/Libertarianmoderate/Archive suggests you had/have sockpuppets, at least at Wikivoyage. You were also blocked, then unblocked in December (description you deleted from your Talk page). Highly unlikely you will ever make Admin. David notMD (talk) 02:42, 29 January 2019 (UTC)
I suggest that you spend the next three years (at least) making only constructive edits, and no silly comments. Also avoid creating or using any sockpuppet accounts, and show that you have a thorough understanding of Wikipedia policies, then you might consider applying, and some editors might vote for you. I've been editing for more than ten years, and do not yet feel that I have a thorough enough understanding of some policies to apply for adminship. Dbfirs 09:06, 29 January 2019 (UTC)
Edits like this [2] would suggest that you are not serious about editing here let alone gaining admin rights. Theroadislong (talk) 10:18, 29 January 2019 (UTC)
User:Theroadislong - I think that editors like the one in question are always serious about wanting admin privileges, even if they are not serious about collaborative editing. That is why we need to be careful about them. Robert McClenon (talk) 19:07, 30 January 2019 (UTC)

## Update Biography Photo

I would like to replace the biography photo of my wife Deborah Chase Hopkins with a more current photo. How do I do that? THANKS! — Preceding unsigned comment added by Hopflys (talkcontribs) 17:58, 30 January 2019 (UTC)

Hopflys, You should read the WP:COI policy first then use {{request edit}} on the article talk page. RhinosF1(chat)(status)(contribs) 18:13, 30 January 2019 (UTC)
Also, Hopflys, you need to be aware of copright issues. Wikipedia requires that most pictures be licensed in a way that anybody can reuse them for any purpose. If you, or your wife, or somebody associated with you has (i.e. holds the copyright of) a suitable picture, and is willing to release it, it would be most welcome. They should go to the Upload wizard, and upload the picture to Wikimedia commons; then it can be used in an article. See donating copyright materials. --ColinFine (talk) 18:19, 30 January 2019 (UTC)
Hello Hopflys, if you take a photo of yourself, you could release it under an appropriate license. Usually professional photographers do not release their photos under a license acceptable to Wikipedia. —teb728 t c 19:37, 30 January 2019 (UTC)

## Undefined Rejection

Hello,

I recently submitted two separate articles for publishing and both were rejected for an undefined reason..

In each case the reviewer left a comment on the draft page. --David Biddulph (talk) 20:10, 27 January 2019 (UTC)
And you are actually three for three on declined. Bluntly, your references are not good enough to confirm these businesses or people as notable by Wikipedia's standards. A couple were one-sentence mentions, when what is needed are longer, more detailed publications about the topics. One was a interview with the subject. What a person says about themselves or their business is not a reliable source. For Draft:Jersey Champs in particular, your 2nd and 3rd refs are both to the same interview. Your 1st ref is just a company financial profile. David notMD (talk) 20:15, 27 January 2019 (UTC)
Professor talbot, I am sorry but I have deleted your drafts as unambiguously promotional. Please be aware that Wikipedia is not a promotional platform. Cullen328 Let's discuss it 02:17, 28 January 2019 (UTC)
OP now blocked as a sock. --David Biddulph (talk) 20:40, 30 January 2019 (UTC)

## William Sherrill

Can an admin please tell me what was here? I don't like to overwrite things. I assume it may be about a non-notable person with this name in the contemporary film industry or possibly the Minister from North Carolina? Thanks. I am about to redirect to William L. Sherrill FloridaArmy (talk) 21:24, 30 January 2019 (UTC)

It was a biography about someone nonnotable from the 18th century. Based on the text I think you are safe to create the redirect. 331dot (talk) 21:32, 30 January 2019 (UTC)

## Port of Key West Essay to Encyclopedic style

Hello. I am wondering what needs to be changed about Port of Key West. I know thee is something wrong with Port of Key West but I do not know what it is. Whether I am told or a more experience editor fixes the problem, the problem is fixed. Please fix this. And notify me (or perhaps not the latter!) Also, a rating on the Importance Scale may be helpful. (Mr. Holup (talk) 22:28, 30 January 2019 (UTC))

Hello!

My entry was deleted because there was copyrighted contend in it. I think the relevant content is a table. The owner of the original article asked me to put in there. So my question is if there is a way to upload the table with his permission even though it's copyrighted? If yes how could he give this permission?

Thank you! Gianna — Preceding unsigned comment added by GiannaHenkel (talkcontribs) 07:23, 28 January 2019 (UTC)

The process for him to release the copyright, if he wishes to do so, is at WP:Donating copyrighted material. Otherwise, you will have to reword things in your own words. --David Biddulph (talk) 07:29, 28 January 2019 (UTC)

Thans for the quick reply! Is there also a way to find out if there are other copyrighted phrases in the text? — Preceding unsigned comment added by GiannaHenkel (talkcontribs) 07:38, 28 January 2019 (UTC)

Anything that has previously been published elsewhere is copyrighted (whether or not specifically labelled as such), unless specifically defined as free from copyright or released under an appropriate licence. There is further explanation at WP:FAQ/Copyright. The simple answer is to write the article in your own words. --David Biddulph (talk) 07:46, 28 January 2019 (UTC)
On your User page, you will need to declare whether your connection to the owner/author of the table is paid. If not paid, you will still need to indicate a conflict of interest. David notMD (talk) 10:57, 28 January 2019 (UTC)


text: You will receive a … Most of RuneScape's content – completely free – and a fresh level 1 start means an adventure-filled, high-risk world for everyone. Player killing differs from other forms of combat in that players do not fight against monsters whose actions are defined by RuneScape's game engine. The Compare users feature on the hiscores is now functioning correctly. Since Corrupt dragon equipment is also available to non-members, it has no special attack in non member worlds. The Stronghold Slayer Cave is a vast network of tunnels recently discovered beneath the Gnome Stronghold. Tune in to our next Q&A livestream tonight at 5pm GMT as we discuss Nightmare Zone XP Rates. PvP worlds (also known as Player-versus-Player worlds) were released on 15 October 2008. PvP worlds were removed on 1 February 2011 by an update that brought the original Wilderness and unlimited trading prices back. Nevertheless, when a player is killed, the player loses nothing and will appear back at the start point. Also, players often switch worlds to find more favourable conditions (e.g. The Ancient Warriors' equipment all come in two states: The list of available equipment are as follows: Sometimes, you will get ancient artefacts. During this time, the player was safe from all players except the player(s) who triggered the timer. The Leaf-bladed Sword is now available as a drop from Kurask & Turoth, requiring 50 Attack and 55 Slayer to wield. When logging into a PvP world, players were warned and given the option to return to the lobby to select another world. https://oldschoolrunescape.fandom.com/wiki/Update:Play_DarkScape_-_Free-to-Play_Open_World_PvP?oldid=6446213. The "immunity" also worked during. Take your favorite fandoms with you and never miss a beat. Emerald Benedict will no longer disappear under certain conditions. This is a world for the taking with wit, guile and strength, and we can't wait to see what you do with it. This page was last modified on 18 June 2019, at 01:01. Upon killing a skulled opponent, you will always get the items they were wearing and carrying, unless the item is (or was) untradeable, in which case will usually turn into a stack of gold coins according to its value. These can be traded to Mandrith in Edgeville bank or Nastroth in Lumbridge castle for a set amount of coins. A "flaming skull" icon would appear on the screen to notify players when they enter these areas. On the day PvP worlds were introduced, lobsters, sharks, and swordfish especially, but also many other types of food and potions, were nearly impossible to come by at the Grand Exchange due to the massive amount of demand. This made it difficult to obtain valuable drops. For the fictional world in which. When PvP worlds were introduced, prices for Rune, Dragon, Barrows, runite ore/bars, potions and also many other types of armour skyrocketed. With DarkScape, we're trying something new and exciting, taking RuneScape's wealth of content and changing the fundamental rules to create a whole new experience – something not possible in RuneScape itself. Another batch of Slayer Rewards sees eight more features added to the slayer points store; you can now unlock larger amounts of Ankou, Suqah, Spiritual Mages, Black & Metal Dragons and Abyssal, Greater & Black Demons. World 114 may need to be added to the list. This rotation is currently inactive; they act as regular unthemed worlds. Scamming is as old as RuneScape itself, and the wide range of scams range from simple and obvious to clever and complex. The World (currently 137) where players can kill each other in the Wilderness where the Protect item prayer and curse are disabled.. Role-playing [edit | edit source]. If two players were each other's target on a bounty world, one could attack the other even when already in battle in a single-way combat zone. If using the World Switcher instead, a confirmation will appear. Warp9pnt9 09:47, October 26, 2011 (UTC), From the RuneScape Wiki, the wiki for all things RuneScape, World 114 - "Skill total (1500)" is now a "High-risk Wilderness world", https://runescape.wiki/w/Talk:High_Risk_Wilderness_world?oldid=28765406. This week's update introduces High Risk PKing worlds, the Stronghold Slayer Cave and another batch of Slayer Rewards. The Steam Battlestaff now properly checks for runes in your inventory. Give us your ideas and feedback on Reddit and the forums, and – most importantly – get in game and start backstabbing, brutalising and conniving. Over the next week we'll be finishing off the Cave Kraken, the level 87 Slayer monster that will live in the new cave. "Safe" activities also allow player-versus player combat. There were a number of "safe zones" within a PvP world where players were not allowed to attack one another. However when equipped with dragon arrows and use the special attack, they can be deadly and can kill you in a second. When PvP worlds were released, it was possible to auto-login to them, and unprepared people were killed without notice. This was only a text change in the world selection screen, with no impact on the actual worlds. Some of these areas were as follows: If a player ran into a safe zone while in combat, a 10-second countdown timer appeared. They provide as much as 400% bonus (additive) to experience, quadrupling the usual experience gained. If the player is in the Wilderness, the range increased as the player travels deeper, directly based on the level of Wilderness the player is in. Mods Ash, John C, Mat K & Reach You will receive a warning before logging into PvP & High Risk worlds. It was hard to argue that those less successful in the wilderness before the removal of the wilderness had not had their profits increased, nor was it easy to argue that those who were successful before the removal of the wilderness had not had their profits heavily curtailed. Players are also prevented from teleporting while their special attack bar is activated on these worlds. (Most of the terms listed below do not apply to the PvP worlds as they are today, but as they were before getting skulled when logging into PvP/bounty worlds.). Any player within a particular level range of Combat level can be attacked. RuneScape members get additional benefits to help with quicker progression. Worlds 337 (PvP) & 365 are now High Risk worlds. Routefinding at Yanille bank has been improved. Many players had criticised the PvP worlds as a bad substitute to the old wilderness. Most of the time, the items dropped were normal items, such as weapons and armour from non-PvP worlds. Do we have a surprise for you. This will choose the best world for you based on available space and your location. Do places besides the wilderness exist on high-risk pvp worlds? Skill total worlds are worlds that are locked to accounts that do not meet the required Total level to enter. "World" redirects here. In August 2007, Jagex added a new column to the world select screen highlighting those worlds with associated activities, especially those team-based events like Trouble Brewing, to make it easier to find people with similar ideas. We'll also get started on some of the quality-of-life jobs from Content Poll #15. ores, trees) are all managed individually for each server. The official role-playing world for members is world 42, and the official world for free-to-play is world 41, though other unofficial worlds may be used. This way, a player could start off with a weakened target for an easier kill. Some players argued player killing in a larger area makes up for the loss of profit for those skilled in player killing. Routefinding at Yanille bank has been improved. ", Some players who abused a bug in which they could not be attacked on PvP worlds and hence gain Earning Potential with little risk were banned for approximately 3 days. Old School RuneScape Wiki is a FANDOM Games Community. If they were not in a hotzone, their potential would rise 10% every 30 minutes with a maximum of 40% only. Wilderness rules everywhere means heart-pounding PvP combat. A player could be attacked by another player outside their range, if the other player had the player within their range. Level range for a player with a Combat level of 96. Toggling Auto Retaliate no longer disrupts movement. Thus the PvP solution is often viewed as more than a game-fix, and actively a Jagex policy of redistributing the profits gained during player killing. Furthermore, you had to wait hours to gain EP if you want a good drop, something which many players found frustrating. There were certain areas in RuneScape called "hot zones". Also, upon revealing ClusterFlutterer, Jagex stated that over 1.5 million bots had been recently banned. The first time you logged to a PvP world you would appear at Lumbridge, future login attempts would allow you to stand where you last logged out before you entered a PvP world. Sign up for membership and re-live the adventure. A common tactic was to run out while the other player is retaliating to restart the timer. However, I am not sure if this new change is permanent or not. According to Jagex, the countdown timer was used to prevent players from using "hit and run" tactics or "Rushing", although rushing was still a major part of PvP worlds. While on these worlds you can NOT activate the Protect Item prayer. Additionally, players (along with chat messages) contained in one world will not be visible to players in another world. The clue box need only be in the player's inventory to protect a clue scroll. Scamming is the act of stealing money, items or accounts from another player through deception or trickery. The only possible ways of interaction between RuneScape worlds is private chat using the Friends List or through Clan Chat. The Armadyl helmet's model has been improved slightly for female characters. Also, note that World 365 is a "safe" world unless you go into the Wilderness as it is not a PvP world. $\text{level range} = \lfloor 1.1 \times \text{Combat level} + \text{Wilderness level} + 5\rfloor$. A server, world or W is a computer which hosts RuneScape. We've kept DarkScape quiet so everyone can come to it completely fresh. Toggling Auto Retaliate no longer disrupts movement.


text:
# All Science Fair Projects

## Science Fair Project Encyclopedia for Schools!

 Search    Browse    Forum  Coach    Links    Editor    Help    Tell-a-Friend    Encyclopedia    Dictionary

# Science Fair Project Encyclopedia

For information on any area of science that interests you,
enter a keyword (eg. scientific method, molecule, cloud, carbohydrate etc.).
Or else, you can start by choosing any of the categories below.

# Nonlinear optics

Nonlinear optics is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the polarization P responds nonlinearly to the electric field E of the light. This nonlinearity is typically only observed at very high light intensities such as provided by pulsed lasers.

Nonlinear optics gives rise to a host of optical phenomena:

 Contents

## Frequency mixing processes

• Second harmonic generation (SHG), or frequency doubling, generation of light with a doubled frequency (half the wavelength);
• Sum-frequency generation (SFG), generation of light with a frequency that is the sum of two other frequencies (SHG is a special case of this);
• Third harmonic generation (THG), generation of light with a tripled frequency (one-third the wavelength) (usually done in two steps: SHG followed by SFG of original and frequency-doubled waves);
• Difference-frequency generation (DFG), generation of light with a frequency that is the difference between two other frequencies;
• Parametric amplification, amplification of a signal input in the presence of a higher-frequency pump wave, at the same time generating an idler wave (can be considered as DFG);
• Parametric oscillation, generation of a signal and idler wave using a parametric amplifier in a resonator (with no signal input);
• Parametric generation, like parametric oscillation but without a resonator, using a very high gain instead;
• Optical rectification, generation of quasi-static electric fields.

## Other nonlinear processes

• Optical Kerr effect, intensity dependent refractive index;
• Self focusing;
• Self-phase modulation (SPM);
• Cross-phase modulation (XPM);
• Four-wave mixing (FWM), can also arise from other nonlinearities.
• Raman scattering, interaction of photons with optical phonons;
• Raman amplification,
• Optical phase conjugation.
• Brillouin scattering, interaction of photons with acoustic phonons;
• Optical phase conjugation.
• Two-photon absorption, simultaneous absorption of two photons, transferring the energy to a single electron;
• Multiple photoionisation, near-simultaneous removal of many bound electrons by one photon.

## Related processes

In these processes, the medium has a linear response to the light, but the properties of the medium are affected by other causes:

• Pockels effect, the refractive index is affected by a static electric field; used in electro-optic modulators;
• Acousto-optics, the refractive index is affected by acoustic waves (ultrasound); used in acousto-optic modulators .

## Frequency-mixing processes

One of the most commonly-used frequency-mixing processes is frequency doubling or second-harmonic generation. With this technique, the 1064-nm output from Nd:YAG lasers or the 800-nm output from Ti:sapphire lasers can be converted to visible light, with wavelengths of 532 nm (green) or 400 nm (violet), respectively.

Practically, frequency-doubling is carried out by placing a special crystal in a laser beam under a well-chosen angle. Commonly-used crystals are BBO (β-barium borate), KDP (potassium dihydrophosphate), and lithium niobate. These crystals have the necessary properties of being strongly birefringent (necessary to obtain phase matching, see below), having a specific crystal symmetry and of course being transparent for and resistant against the high-intensity laser light.

### Theory

A number of nonlinear optical phenomena can be described as frequency-mixing processes. In general, the dielectric polarization P(t) at time t in a medium can be written as a power series in the electrical field:

Failed to parse (unknown function \propto): P(t) \propto \chi^{(1)} E(t) + \chi^{(2)} E^2(t) + \chi^{(3)} E^3(t) + \cdots

.

Here, the coefficients χ(n) are the n-th order susceptibilities of the medium. For any three-wave mixing process, the second-order term is crucial; it is only nonzero in media that have a broken inversion symmetry. If we write

$E(t) = E_1 e^{i \omega_1 t} + E_2 e^{i \omega_2 t} + {\rm c.c.}$,

where c.c. denotes the complex conjugate, the second-order term in will read

Failed to parse (unknown function \propto): P^{(2)}(t) \propto \sum\chi^{(2)} n_0 E_1^{n_1} E_2^{n_2} e^{i (m_1\omega_1 + m_2\omega_2) t } + {\rm c.c.}

,

where the summation is over

$(n_0,n_1,n_2,m_1,m_2) = (1,2,0,2,0),\; (1,0,2,0,2),\; (2,2,0,0,0),\; (2,0,2,0,0),\; (2,1,1,1,-1),\; (2,1,1,1,1)$.

The six combinations (nx,mx) correspond, respectively, to the second harmonic of E1, the second harmonic of E2, the optically rectified signals of E1 and E2, the difference frequency, and the sum frequency. A medium that is thus pumped by the fields E1 and E2 will radiate a field E3 with an angular frequency ω3 = m1ω1 + m2ω2.

Note: in this description, χ(2) is a scalar. In reality, χ(2) is a tensor whose components depend on the combination of frequencies.

Parametric generation and amplification is a variation of difference frequency generation, where the lower-frequency one of the two generating fields is much weaker (parametric amplification) or completely absent (parametric generation). In the latter case, the fundamental quantum-mechanical uncertainty in the electric field initiates the process.

### Phase matching

The above ignores the position dependence of the electrical fields. In a typical situation, the electrical fields are traveling waves described by

$E_j(\mathbf{x},t) = e^{i(\omega_j t - \mathbf{k}_j \cdot \mathbf{x})}$,

at position $\mathbf{x}$, with the wave vector $\mathbf{k}_j = n(\omega_j)\omega_j/c$, where c is the velocity of light and nj) the index of refraction of the medium at angular frequency ωj. Thus, the second-order polarization angular frequency ω3 is

Failed to parse (unknown function \propto): P^{(2)} (\mathbf{x}, t) \propto E_1^{n_1} E_2^{n_2} e^{i (\omega_3 t - (m_1 \mathbf{k}_1 + m_2 \mathbf{k}_2)\cdot\mathbf{x})}

.

At each position $\mathbf{x}$, the oscillating second-order polarization radiates at angular frequency ω3 and a corresponding wave vector $\mathbf{k}_3 = n(\omega_3)\omega_3/c$. Constructive interference, and therefore a high intensity ω3 field, will occur only if

$\mathbf{k}_3 = m_1 \mathbf{k}_1 + m_2 \mathbf{k}_2$.

The above equation is known as the phase matching condition. Typically, three-wave mixing is done in a birefringent crystalline material (I.e., the refractive index depends on the polarization and direction of the light that passes through.), where the polarizations of the fields and the orientation of the crystal are chosen such that the phase-matching condition is fulfilled.

### Higher-order frequency mixing

The above holds for χ(2) processes. It can be extended for processes where χ(3) is nonzero, something that is generally true in any medium without any symmetry restrictions. Third-harmonic generation is a χ(3) process, although in laser applications, it is usually implemented as a two-stage process: first the fundamental laser frequency is doubled and then the doubled and the fundamental frequencies are added in a sum-frequency process. The Kerr effect can be described as a χ(3) as well.

### Optical phase conjugation

It is possible, using nonlinear optical processes, to exactly reverse the propagation direction and phase variation of a beam of light. The reversed beam is called a conjugate beam, and thus the technique is known as optical phase conjugation (also called time reversal, wavefront reversal and retroreflection).

The most common way of producing optical phase conjugation is to use a four-wave mixing technique, though it is also possible to use processes such as stimulated Brillouin scattering. A device producing the phase conjugation effect is known as a phase conjugate mirror (PCM).

For the four-wave mixing technique, we can describe four beams (j = 1,2,3,4) with electric fields:

$\Xi_j(\mathbf{x},t) = \frac{1}{2} E_j(\mathbf{x}) e^{i (\omega_j t - \mathbf{k}\cdot\mathbf{x})} + \mbox{c.c.}$

where Ej are the electric field amplitudes. Ξ1 and Ξ2 are known as the two pump waves, with Ξ3 being the signal wave, and Ξ4 being the generated conjugate wave.

If the pump waves and the signal wave are superimposed in a medium with a non-zero χ(3), this produces a nonlinear polarization field:

PNL = ε0χ(3)1 + Ξ2 + Ξ3)3

resulting in generation of waves with frequencies given by ω = ±ω1 ±ω2 ±ω3 in addition to third harmonic generation waves with ω = 3ω1, 3ω2, 3ω3.

As above, the phase-matching condition determines which of these waves is the dominant. By choosing conditions such that ω = ω1 + ω2 - ω3 and k = k1 + k2 - k3, this gives a polarization field:

$P_\omega = \frac{1}{2} \chi^{(3)} \epsilon_0 E_1 E_2 E_3^* e^{i(\omega t - \mathbf{k} \cdot \mathbf{x} ) } + \mbox{c.c.}$.

This is the generating field for the phase conjugate beam, Ξ4. Its direction is given by k4 = k1 + k2 - k3, and so if the two pump beams are counterpropagating (k1 = -k2), then the conjugate and signal beams propagate in opposite directions (k4 = -k3). This results in the retroreflecting property of the effect.

Further, it can be shown for a medium with refractive index n and a beam interaction length l, the electric field amplitude of the conjugate beam is approximated by

$E_4 = \frac{i \omega l}{2 n c} \chi^{(3)} E_1 E_2 E_3^*$

(where c is the speed of light). If the pump beams E1 and E2 are plane (counterpropagating) waves, then:

Failed to parse (unknown function \propto): E_4(\mathbf{x}) \propto E_3^*(\mathbf{x})

that is, the generated beam amplitude is the complex conjugate of the signal beam amplitude. Since the imaginary part of the amplitude contains the phase of the beam, this results in the reversal of phase property of the effect.

Note that the constant of proportionality between the signal and conjugate beams can be greater than 1. This is effectively a mirror with a reflection coefficient greater than 100%, producing an amplified reflection. The power for this comes from the two pump beams, which are depleted by the process.

The frequency of the conjugate wave can be different from that of the signal wave. If the pump waves are of frequency ω1 = ω2 = ω, and the signal wave higher in frequency such that ω3 = ω + Δω, then the conjugate wave is of frequency ω4 = ω - Δω. This is known as frequency flipping.


text:
# Are the weaknesses of my functions attackable?

I got specific problem with my functions in $$128$$-bit block cipher. One round of encryption is like that:

$$input$$ $$\rightarrow$$ $$F(k_{i},input)$$ $$\rightarrow$$ reverse block $$\rightarrow$$ $$F(k_{i+1},reversed \ block)^{-1}$$ $$\rightarrow$$ $$output$$

Every function got a specific $$128$$-bit key, but keys do not change some properties of that function. $$F^{-1}$$ means that we are looking for such input to function $$F(k_{i+1})$$ that will give us such a reversed block.

The first problem is with numbers divisible by $$2$$. Every input block in the function of form 000...0001... also will give us the same first zeros and one. For example:

000001...0111101...

go into:

000001...1111001...

and 0001011... go into 0001111..., but with a different key, it can be 0001000... and so on.

All the rest of the block depends on the key and there is no known way to guess it without the key. It also means that block 000...0001 always gives the same block 000...0001 and a block of only zeros goes into the same block. It also means that every block with $$1$$ as the first bit will also go into a block with $$1$$ as the first bit. I think it can be solved, by XORing with some key before every round, let's ignore that problem for now.

The second problem is that every $$input + 2^{n}\cdot l$$ will give an output block with the same first $$n$$ bits in such function.

Can you find a way to attack it? The main idea is to avoid problems by reversing blocks and then looking for such input to function, which will give us such a reversed block - it destroys patterns that we have in that function. Let's say we want to encrypt block 000...0001. We know what block will give us the first function (exactly the same, by definition), but without the key of the second function, we can't tell which number is giving 1000...000 block in that next function $$F^{-1}$$. We can only tell that such block will definitely have the bit 1 at the beginning (because in function $$F$$ all blocks with 1 at the beginning always gives output with 1 at the beginning).