text:
\section{Methods}
\subsection{Data Collection}
The dataset we use in this study is extracted from the August 2013 dump of English Wikipedia\footnote{http://dumps.wikimedia.org/enwiki/20130805/}, which includes the complete edit history of all pages from the inception of Wikipedia. Project members generally claim an article in its scope by inserting project template in article talk page. We parsed the link to WikiProject in article talk pages and accumulated all articles tagged by a WikiProject up to a specific quarter to estimate its project scope. We parsed the historical edits of a project's member list to identify members and their joining time for each WikiProject. WikiProjects generally provide main pages or subpages to maintain the list of project members, and any editors can join a project by adding one's username to the member list and then leave the project by removing the username from the list.

We calculated the edit longevity of each edit to articles using the WikiTrust software by \cite{Adler2007}. We then obtained the amount of work done by project members in a quarter by accumulating all the edits or the edit longevity of edits contributed by members to project scope articles. We constructed the collaboration network for each WikiProject in a quarter by considering the co-edit activities of members to project scope articles: if two members made edits to an article, and both the edit longevity of their edits were positive, then the two members established a co-authorship connection. By accumulating all the connections among members within a project, we obtained the collaboration network for the project.

We are interested in exploring how member turnover and social capital losses influence project productivity. To make the results more meaningful, we only included those WikiProjects which had at least 50 accumulated tagged articles and at least three members (the minimal size of group) in this study. As a result, we obtained a longitudinal dataset of 891 WikiProjects each with at least 1 to 35 quarterly observations, each observation recording the characteristics, network measures and outcomes of a project in a quarter.

\subsection{Model Specification}
A preliminary analysis of the data revealed that some of the independent variables were positively skewed. Following \cite{Gelman2007}, we performed a logarithmic transformation on these independent variables to make the coefficients more comparable. To explore the possible non-linear relationship between social capital losses and project performance, we included the squares of the social capital losses in the model. To validate the possible mediated effects that member turnover or network density has on the relationship between social capital losses and performance, we added the interaction of turnover rate (or density) and social capital losses in the model. There is a non-linear dependence of productivity on social capital losses. We fit a second order polynomial (using the poly function in R) and discuss the curvilinear relationship we find. We chose a second order polynomial (quadratic) over a smoothing spline to facilitate comparison with existing work (e.g. \cite{Shaw2005}). The preliminary analysis also suggested that the collinearity of the model is very high (with kappa value larger than 30), which indicates potentially harmful collinearity among variables \citep{Baayen2008}. We used z-score to scale the $\textrm{Mean~Tenure}$ variable, which reduces the collinearity of the model significantly. To ease the interpretation, we represent the log-transformed and z-score normalization variables with``Ln" and ``Sc" prefix, respectively.

Our data has a nested structure -- quarterly observations nested within projects -- which suggest Hierarchical Linear Model \citep{Bryk1992} for our analysis. HLM is an advanced form of linear model which takes into account potential autocorrelations among time periods that are nested with the same project, while allowing us to examine the main effects of independent variables on dependent variables. Meanwhile, to account for project-level unobserved differences, we include project level random effects in the model. The model specification is as follows:
\begin{equation*}
{\fontsize{8.0pt}{8.0pt}\selectfont
\begin{aligned}[c]
\textrm{LnDV}_{jt}&=\beta_{0}+\beta_{1}\textrm{Quarter}_{jt}+\beta_{2}\textrm{Project~creation}_{jt}+\beta_{3}\textrm{LnProject~scope}_{jt}
+\beta_{4}\textrm{LnProject~size}_{jt}\\
&+\beta_{5}\textrm{LnDiscussion~topics}_{jt}+\beta_{6}\textrm{ScMean~tenure}_{jt}+\beta_{7}\textrm{Level~of~controversy}_{jt}
+\beta_{8}\textrm{Tenure~diversity}_{jt} \\
&+\beta_{9}\textrm{Turnover~rate}_{jt}+\beta_{10}\textrm{Density}_{jt}+\beta_{11}\textrm{SC~Losses}_{jt}
+\beta_{12}\textrm{SC~Losses}_{jt}^2 \\
&+\beta_{13}\textrm{SC~Losses}_{jt}\times\textrm{Turnover~rate}_{jt}
+\beta_{14}\textrm{SC~Losses}_{jt}^2\times\textrm{Turnover~rate}_{jt}+{\upsilon}_{j}
\end{aligned}
}
\end{equation*}
where variables are indexed across project ($j$) and quarter ($t$); $\textrm{LnDV}_{jt}$ represents the dependent variable; ${\upsilon}_{j}$ is the random effect at the project level. We obtained our estimates using the \textsf{lmer} function in \textsf{lme4} package \citep{lme42012} for \textbf{R} software (version 2.15.3). We check for violations of the assumption of our regression analyses and find no substantive violations.
\section{Results}
The descriptive statistics and correlation matrix of the study variables are presented in Table \ref{Tab:Descriptive_stats} and Table \ref{Tab:Correlation_matrix}, respectively. It is obvious from Table \ref{Tab:Descriptive_stats} that, the amount of work (i.e., Edit Longevity and Edit Count), discussion topics, project scope and size are of reasonable variation and have a heavily right skewed distribution. By including quarter and random effects in the model, we control for the changes in overall trend of activity within WikiProjects and Wikipedia over time. We observe from Table \ref{Tab:Correlation_matrix} that the correlation between the two measures of project productivity (i.e., Log2(Edit Longevity) and Log2(Edit Count)) is positive and significant (p$<$0.001), suggesting that it is reasonable to use the edit count as a measure of project productivity.

\begin{table}[!htb]
\caption{Correlation Matrix for Variables}
\begin{adjustwidth}{-1.3in}{-1.2in}
\renewcommand{\arraystretch}{1.3}
{\fontsize{8.0pt}{8.0pt}\selectfont
\label{Tab:Correlation_matrix}
\begin{center}
\begin{tabular}{lcccccccccccccc}
  \hline
 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 & 12 & 13 & 14 \\
  \hline
1. Log2(Edit Longevity) & - &  &  &  &  &  &  &  &  &  &  &  &  &  \\
2. Log2(Edit Count) & 0.92 & - &  &  &  &  &  &  &  &  &  &  &  &  \\
3. Quarter & 0.04 & 0.07 & - &  &  &  &  &  &  &  &  &  &  &  \\
4. Project creation & -0.29 & -0.29 & -0.21 & - &  &  &  &  &  &  &  &  &  &  \\
5. LnProject Scope & 0.49 & 0.59 & 0.49 & -0.22 & - &  &  &  &  &  &  &  &  &  \\
6. LnProject size & 0.71 & 0.75 & -0.00 & -0.42 & 0.50 & - &  &  &  &  &  &  &  &  \\
7. LnDiscussion topics & 0.60 & 0.64 & -0.07 & -0.46 & 0.39 & 0.77 & - &  &  &  &  &  &  &  \\
8. ScMean Tenure & -0.01 & 0.01 & 0.57 & 0.08 & 0.31 & -0.16 & -0.18 & - &  &  &  &  &  &  \\
9. Level of controversy & -0.05 & -0.12 & 0.09 & -0.09 & -0.07 & -0.05 & -0.00 & 0.03 & - &  &  &  &  &  \\
10. Tenure Diversity & 0.26 & 0.24 & -0.15 & -0.11 & 0.03 & 0.39 & 0.22 & -0.43 & 0.00 & - &  &  &  &  \\

11. Turnover rate & -0.15 & -0.17 & 0.03 & 0.02 & -0.05 & -0.13 & -0.10 & -0.01 & 0.04 & 0.02 & - &  &  &  \\
12. Density & -0.06 & -0.07 & -0.22 & 0.24 & -0.19 & -0.21 & -0.18 & -0.03 & -0.09 & 0.00 & 0.22 & - &  &  \\
13. SC Losses & -0.08 & -0.11 & -0.02 & 0.00 & -0.07 & -0.03 & -0.05 & -0.07 & 0.04 & 0.04 & 0.23 & 0.16 & - &  \\
14. $\textrm{SC~Losses}^2$ & -0.05 & -0.05 & -0.00 & 0.07 & -0.03 & -0.10 & -0.06 & 0.03 & -0.03 & -0.05 & -0.17 & -0.02 & 0.00 & - \\
   \hline

\end{tabular}
\end{center}
}
\end{adjustwidth}
\end{table}

\begin{table}[!htb]
\caption{HLM results of Predicting Amount of Work Done by Project Members (Using Maximum Likelihood estimates)}
\begin{adjustwidth}{-1.3in}{-1.2in}
\label{Tab:HLM-results}
\renewcommand{\arraystretch}{1.3}
{\fontsize{8.0pt}{8.0pt}\selectfont
\begin{center}
\begin{tabular}{lr@{}lr@{}lr@{}lr@{}lr@{}lr@{}lr@{}lr@{}lr@{}lr@{}l}
\hline
\multirow{2}{*}{Variables} & \multicolumn{ 4}{c}{\textbf{Model 1}} & \multicolumn{ 4}{c}{\textbf{Model 2}} & \multicolumn{ 4}{c}{\textbf{Model 3}} & \multicolumn{ 4}{c}{\textbf{Model 4a}} & \multicolumn{ 4}{c}{\textbf{Model 4b}} \\
\cline{ 2- 21}
 & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} \\ \hline

\multicolumn{21}{l}{\multirow{2}{*}{\textbf{Log2(Edit longevity)} as dependent variable (\#Obs: 16048, \#WikiProjects: 890, \#Quarters:1--35)}} \\
\multicolumn{21}{l}{} \\
Intercept & 3&.493{$^{***}$} & 0&.259 & 4&.115{$^{***}$} & 0&.259 & 4&.121{$^{***}$} & 0&.26 & 4&.119{$^{***}$} & 0&.259 & 4&.122{$^{***}$} & 0&.259 \\
Quarter & -0&.045{$^{***}$} & 0&.004 & -0&.043{$^{***}$} & 0&.004 & -0&.043{$^{***}$} & 0&.004 & -0&.043{$^{***}$} & 0&.004 & -0&.043{$^{***}$} & 0&.004 \\
Project creation & -0&.012 & 0&.01 & -0&.03{$^{**}$} & 0&.01 & -0&.031{$^{**}$} & 0&.01 & -0&.03{$^{**}$} & 0&.01 & -0&.03{$^{**}$} & 0&.01 \\
LnProject scope & 0&.241{$^{***}$} & 0&.014 & 0&.253{$^{***}$} & 0&.014 & 0&.253{$^{***}$} & 0&.014 & 0&.251{$^{***}$} & 0&.014 & 0&.253{$^{***}$} & 0&.014 \\
LnProject size & 1&.386{$^{***}$} & 0&.031 & 1&.249{$^{***}$} & 0&.032 & 1&.248{$^{***}$} & 0&.032 & 1&.246{$^{***}$} & 0&.032 & 1&.247{$^{***}$} & 0&.032 \\
LnDiscussion topics & 0&.16{$^{***}$} & 0&.014 & 0&.159{$^{***}$} & 0&.014 & 0&.159{$^{***}$} & 0&.014 & 0&.161{$^{***}$} & 0&.014 & 0&.161{$^{***}$} & 0&.014 \\
ScMean tenure & 0&.255{$^{***}$} & 0&.033 & 0&.246{$^{***}$} & 0&.032 & 0&.245{$^{***}$} & 0&.032 & 0&.239{$^{***}$} & 0&.032 & 0&.246{$^{***}$} & 0&.032 \\
Level of controversy & -0&.566{$^{**}$} & 0&.164 & -0&.518{$^{**}$} & 0&.162 & -0&.516{$^{**}$} & 0&.162 & -0&.508{$^{**}$} & 0&.162 & -0&.508{$^{**}$} & 0&.162 \\
Tenure diversity & 0&.697{$^{***}$} & 0&.101 & 0&.74{$^{***}$} & 0&.1 & 0&.74{$^{***}$} & 0&.1 & 0&.724{$^{***}$} & 0&.1 & 0&.74{$^{***}$} & 0&.1 \\
Turnover rate &  & & &  & -0&.478{$^{***}$} & 0&.032 & -0&.458{$^{***}$} & 0&.033 & -0&.397{$^{***}$} & 0&.036 & -0&.461{$^{***}$} & 0&.033 \\
Density$^{\dagger}$ & & & & & 2&.596{$^{***}$} & 0&.19 & 2&.616{$^{***}$} & 0&.19 & 2&.495{$^{***}$} & 0&.193 & 2&.511{$^{***}$} & 0&.194 \\
SC Losses$^{\dagger}$ &  & & &  & -11&.341{$^{***}$} & 1&.622 & -11&.722{$^{***}$} & 1&.626 & -5&.838{$^{**}$} & 2&.224 & -7&.476{$^{**}$} & 2&.851 \\
$\textrm{SC~Losses}^2$$^{\dagger}$ &  & & &  &  & & &  & 5&.38{$^{**}$} & 1&.596 & 3&.834{$^{t}$} & 2&.151 & 0&.215 & 2&.827 \\
SC Losses$^{\dagger}$ $\times$ Turnover rate &  & & &  &  & & &  &  & & &  & -12&.263{$^{***}$} & 3&.288 &  & & &  \\
$\textrm{SC~Losses}^2$$^{\dagger}$ $\times$ Turnover rate &  & & &  &  & & &  &  & & &  & 2&.493 & 3&.699 &  & & &  \\
SC Losses$^{\dagger}$ $\times$ Density$^{\dagger}$ &  & & &  &  & & &  &  & & &  &  & & &  & -34&.47{$^{*}$} & 17&.283 \\
$\textrm{SC~Losses}^2$$^{\dagger}$ $\times$ Density$^{\dagger}$ &  & & &  &  & & &  &  & & &  &  & & &  & 40&.64{$^{*}$} & 17&.281 \\
\multicolumn{21}{l}{\multirow{2}{*}{Fit}} \\
\multicolumn{21}{l}{} \\
AIC &  \multicolumn{4}{l}{61235.0} &  \multicolumn{4}{l}{60862.0}  &  \multicolumn{4}{l}{60852.0}  &  \multicolumn{4}{l}{60839.0}  &  \multicolumn{4}{l}{60848.0}  \\
BIC &  \multicolumn{4}{l}{61320.0} &  \multicolumn{4}{l}{60969.0}  &  \multicolumn{4}{l}{60968.0}  &  \multicolumn{4}{l}{60970.0}  &  \multicolumn{4}{l}{60979.0}  \\
logLik &  \multicolumn{4}{l}{-30607.0} &  \multicolumn{4}{l}{-30417.0}  &  \multicolumn{4}{l}{-30411.0}  &  \multicolumn{4}{l}{-30403.0}  &  \multicolumn{4}{l}{-30407.0}  \\
$\chi^2$~/~df vs. previous nested model &  \multicolumn{4}{l}{} &  \multicolumn{4}{l}{379.53{$^{***}$}}  &  \multicolumn{4}{l}{11.36{$^{***}$}}  &  \multicolumn{4}{l}{17.19{$^{***}$}}  &  \multicolumn{4}{l}{8.10{$^{*}$}}  \\ \hline
\multirow{2}{*}{Variables} & \multicolumn{ 4}{c}{\textbf{Model 1}} & \multicolumn{ 4}{c}{\textbf{Model 2}} & \multicolumn{ 4}{c}{\textbf{Model 3}} & \multicolumn{ 4}{c}{\textbf{Model 4a}} & \multicolumn{ 4}{c}{\textbf{Model 4b}} \\
\cline{ 2- 21}
 & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} & \multicolumn{2}{c}{Coeff.} & \multicolumn{2}{c}{S. E.} \\ \hline
\multicolumn{21}{l}{\multirow{2}{*}{\textbf{Log2(Edit count)} as dependent variable (\#Obs: 16171, \#WikiProjects: 891, \#Quarters: 1--35)}} \\
\multicolumn{21}{l}{} \\

Intercept & 0&.016 & 0&.18 & 0&.474{$^{**}$} & 0&.178 & 0&.48{$^{**}$} & 0&.178 & 0&.475{$^{**}$} & 0&.178 & 0&.484{$^{**}$} & 0&.178 \\
Quarter & -0&.025{$^{***}$} & 0&.003 & -0&.023{$^{***}$} & 0&.003 & -0&.023{$^{***}$} & 0&.003 & -0&.023{$^{***}$} & 0&.003 & -0&.023{$^{***}$} & 0&.003 \\
Project creation & 0&.014{$^{*}$} & 0&.007 & -0&.0001 & 0&.007 & -0&.001 & 0&.007 & -0&.0003 & 0&.007 & -0&.0003 & 0&.007 \\
LnProject scope & 0&.299{$^{***}$} & 0&.01 & 0&.307{$^{***}$} & 0&.01 & 0&.307{$^{***}$} & 0&.01 & 0&.307{$^{***}$} & 0&.01 & 0&.307{$^{***}$} & 0&.01 \\
LnProject size & 1&.132{$^{***}$} & 0&.022 & 1&.031{$^{***}$} & 0&.022 & 1&.03{$^{***}$} & 0&.022 & 1&.031{$^{***}$} & 0&.022 & 1&.03{$^{***}$} & 0&.022 \\
LnDiscussion topics & 0&.157{$^{***}$} & 0&.01 & 0&.155{$^{***}$} & 0&.01 & 0&.155{$^{***}$} & 0&.01 & 0&.155{$^{***}$} & 0&.01 & 0&.155{$^{***}$} & 0&.01 \\
ScMean tenure & 0&.068{$^{**}$} & 0&.022 & 0&.06{$^{**}$} & 0&.022 & 0&.059{$^{**}$} & 0&.022 & 0&.058{$^{**}$} & 0&.022 & 0&.059{$^{**}$} & 0&.022 \\
Level of controversy & -1&.161{$^{***}$} & 0&.114 & -1&.131{$^{***}$} & 0&.112 & -1&.131{$^{***}$} & 0&.112 & -1&.129{$^{***}$} & 0&.112 & -1&.127{$^{***}$} & 0&.112 \\
Tenure diversity & 0&.14{$^{*}$} & 0&.069 & 0&.174{$^{*}$} & 0&.068 & 0&.175{$^{*}$} & 0&.068 & 0&.168{$^{*}$} & 0&.068 & 0&.172{$^{*}$} & 0&.068 \\

Turnover rate &  & & &  & -0&.345{$^{***}$} & 0&.022 & -0&.332{$^{***}$} & 0&.022 & -0&.315{$^{***}$} & 0&.025 & -0&.333{$^{***}$} & 0&.022 \\
Density$^{\dagger}$ & & & & & 2&.146{$^{***}$} & 0&.13 & 2&.164{$^{***}$} & 0&.13 & 2&.132{$^{***}$} & 0&.132 & 2&.103{$^{***}$} & 0&.133 \\

SC Losses$^{\dagger}$ &  & & &  & -13&.541{$^{***}$} & 1&.126 & -13&.801{$^{***}$} & 1&.127 & -11&.143{$^{***}$} & 1&.547 & -13&.549{$^{***}$} & 1&.961 \\
$\textrm{SC~Losses}^2$$^{\dagger}$ &  & & &  &  & & &  & 3&.939{$^{***}$} & 1&.096 & 4&.843{$^{**}$} & 1&.671 & -0&.109 & 1&.97 \\
SC Losses$^{\dagger}$ $\times$ Turnover rate &  & & &  &  & & &  &  & & &  & -5&.709{$^{*}$} & 2&.266 &  & & &  \\
$\textrm{SC~Losses}^2$$^{\dagger}$ $\times$ Turnover rate &  & & &  &  & & &  &  & & &  & -2&.404 & 2&.823 &  & & &  \\
SC Losses$^{\dagger}$ $\times$ Density$^{\dagger}$ &  & & &  &  & & &  &  & & &  &  & & &  & -3&.978 & 11&.692 \\
$\textrm{SC~Losses}^2$$^{\dagger}$ $\times$ Density$^{\dagger}$ &  & & &  &  & & &  &  & & &  &  & & &  & 32&.119{$^{*}$} & 12&.992 \\

\multicolumn{21}{l}{\multirow{2}{*}{Fit}} \\
\multicolumn{21}{l}{} \\

AIC &  \multicolumn{4}{l}{50019.0} &  \multicolumn{4}{l}{49473.0}  &  \multicolumn{4}{l}{49462.0}  &  \multicolumn{4}{l}{49459.0}  &  \multicolumn{4}{l}{49460.0}  \\

BIC &  \multicolumn{4}{l}{50103.0} &  \multicolumn{4}{l}{49580.0}  &  \multicolumn{4}{l}{49577.0}  &  \multicolumn{4}{l}{49590.0}  &  \multicolumn{4}{l}{49550.0}  \\

logLik &  \multicolumn{4}{l}{-24998.0} &  \multicolumn{4}{l}{-24722.0}  &  \multicolumn{4}{l}{-24716}  &  \multicolumn{4}{l}{-24713.0}  &  \multicolumn{4}{l}{-24713}  \\

$\chi^2$~/~df vs. previous nested model &  \multicolumn{4}{l}{} &  \multicolumn{4}{l}{552.03{$^{***}$}}  &  \multicolumn{4}{l}{12.90{$^{***}$}}  &  \multicolumn{4}{l}{6.35{$^{*}$}}  &  \multicolumn{4}{l}{6.11{$^{*}$}}  \\ \hline

\multicolumn{21}{l}{Note. $\dagger$ one quarter lag for network measures.}  \\
\multicolumn{21}{l}{Significance level: $^{\ast\ast\ast}$ p$<$0.001, $^{\ast\ast}$ p$<$0.01, $^{\ast}$ p$<$0.05, $^{t}$ p$<$0.1.}  \\
\end{tabular}
\end{center}
}
\end{adjustwidth}
\end{table}

Table \ref{Tab:HLM-results} presents the results of our empirical analysis in an incremental manner, with the upper and lower panel including the results when the edit longevity and edit count is used as the dependent variable, respectively. Model 1 is the baseline model including all control variables, Model 2 adds the linear terms for the independent variables into Model 1, Model 3 adds the quadratic term of $\textrm{SC~Losses}$ into Model 2, Model 4a and Model 4b add the interaction terms into Model 3. Comparison of $\chi^2$ reveals that models with interaction terms (Model 4a and Model 4b) fit the data better than the simpler models.

Our results in Model 1 about the significance of control variables are consistent with the findings by \cite{Chen2010}: Five control variables have significant effects on the amount of work (edit longevity or edit count) done by project members (p$<$.001). Specifically:
\begin{itemize}
    \item A project would be more productive if it is of larger scope (0.241 and 0.299) and size (1.386 and 1.132), or if it deals with a less controversial topic (-0.566 and -1.161).
    \item The negative and significant coefficient for quarter variable (-0.045 and -0.025) suggests that when holding other variables constant, projects generally become less productive over time.
    \item Project creation time has very weak effect on edit longevity ($\beta$=-0.045, p$>$0.1) or edit count ($\beta$=0.014, p$<$0.01) if we observe quarterly productivity for projects over a longer period of time, which is the case in this study (observation over 8 years).
    \item The average member tenure and tenure diversity are positively and significantly associated with the amount of work, suggesting that projects with high level of tenure diversity enjoy better group outcomes.
\end{itemize}

In Model 1, the positive and significant coefficient for the discussion topics variable implies that when controlling for other factors, having more discussion topics in project talk pages generally makes a project more productive. Consistent with the results by \cite{Qin2012}, this finding suggests that the amount of information and knowledge resources exchanging among participants via communication in project talk pages has a positive impact on project productivity and efficiency.

In Model 2, all three independent variables have significant effects on group productivity (p$<$.001). The coefficient for network density is positive and significant (2.596 and 2.146), suggesting that when controling for other factors, increasing the connectedness of the collaboration network for a project generally improves its productivity. The negative and significant coefficient for turnover rate (-0.478 and -0.345) implies that controlling for other factors, projects with high levels of turnover in general accomplish less work in a quarter. This provides support for hypothesis \textbf{Ha}.

\begin{figure}[!htb]
\baselineskip=12pt
{\fontsize{10.0pt}{10.0pt}\selectfont
\begin{center}
  \subfloat{\includegraphics[width=0.68\textwidth]{./figs/Social_capital_losses_vs_Log2EditLongevity}}\\%\quad
  \subfloat{\includegraphics[width=0.68\textwidth]{./figs/Social_capital_losses_vs_Log2EditCount}}\\
\end{center}
\caption{A U-shaped relationship for social capital losses and productivity of WikiProjects. The red lines show the model fit for the relationship of $\textrm{SC Losses}$ to $\textrm{Log2(Edit~Longevity)}$ on the left and $\textrm{Log2(Edit~Count)}$ on the right. The y-values of the dots correspond to the observed productivity minus the productivity predicted by all other variables. Thus the scatter plots depicts the covariance of productivity ( $\textrm{Log2(Edit~Longevity)}$ and $\textrm{Log2(Edit~Count)}$) with $\textrm{SC Losses}$ conditional on all other variables.}
\label{fig:sc_losses_productivity}
}
\end{figure}
Model 3 shows that both the linear and squared term of $\textrm{SC Losses}$ are significant in the expected direction. Specifically, the linear term of social capital losses has a negative main effect ($\beta$=-11.722, p$<$0.001 in the edit longevity  model and $\beta$=-13.801, p$<$0.001 in the edit count model) and its quadratic term has a positive effect ($\beta$=5.38, p$<$0.01 for edit longevity and $\beta$=3.939, p$<$0.001 for edit count). As shown in Figure \ref{fig:sc_losses_productivity}, as social capital losses increases from a very low level to a moderate level, the amount of work done by project members declines; after the moderate level, with any further increased in social capital losses from turnover, the amount of work done by project members increases. This finding is consistent with the results by \cite{Shaw2005}. One explanation for this negative curvilinear relationship between social capital losses and group productivity can be found in \cite{Shaw2005}: initially, when social capital losses are low, the loss of structural hole spanners will create the first communication gaps in a network (can also be knowledge gaps or other gaps), which will have a negative effect on group performance; when social capital losses are high, key network relationships have not been well established and maintained, which should be less damaging to group performance. The results provide full support for hypothesis \textbf{Hb}.

\begin{figure}[!htb]
\baselineskip=12pt
{\fontsize{10.0pt}{10.0pt}\selectfont
\begin{adjustwidth}{-.3in}{-.3in}
\begin{center}
  \subfloat{\includegraphics[width=0.68\textwidth]{./figs/Social_capital_losses_vs_member_turnover_on_Log2EditLongevity}}\quad
  \subfloat{\includegraphics[width=0.68\textwidth]{./figs/Social_capital_losses_vs_network_density_on_Log2EditLongevity}}\\
\end{center}
\end{adjustwidth}
\caption{Visualization of the mediated effects of Turnover rate and Network Density on the relationship between social capital losses and project productivity when the edit longevity is the dependent variable.The curves are generated when holding the values of turnover rate (or network density) at a specific level.}
\label{fig:Interaction_Effects}
}
\end{figure}
Hypothesis \textbf{Hc1} states that the negative curvilinear relationship between social capital losses and project productivity is more pronounced when turnover rate is low. In Model 4a, the interaction of turnover rate and the linear term of $\textrm{SC Losses}$ is significant in the expected direction, but the interaction with the squared term is insignificant. We plotted the coefficients to examine the level of support for \textbf{Hc1}. The left figure in Figure \ref{fig:Interaction_Effects} shows this relationship when the edit longevity is the dependent variable\footnote{We observe a similar trend when the edit count is the dependent variable. The figures are omitted due to space limitation.}. Consistent with \cite{Shaw2005}, we also observe that project performance is the most pronounced when social capital losses and turnover rate are at their lowest levels. The figure shows that, with low turnover rate, the curvilinear relationship is negative at low levels of social capital losses, but this effect becomes attenuated as these losses increase beyond moderate levels. One explanation for this can be explained by \cite{Shaw2005}: Members in long-standing groups generally establish routine, trust and norms of reciprocity that reduce opportunistic behaviour. Thus, the effects of the loss of structural hole bridgers should be more pronounced when turnover is low -- a situation in which reciprocity norms and routines are well-established -- than when turnover is high, so key network relationships have not been well maintained. The results provide substantial support for \textbf{Hc1}.

Hypothesis \textbf{Hc2} states that the negative curvilinear relationship between social capital losses and project productivity is more pronounced when network density is high. In Model 4b, the interaction of density and $\textrm{SC Losses}$ is significant (p$<$0.05) in the expected direction when the edit longevity is the dependent variable, but only the interaction with the squared term is significant (p$<$0.05) when the edit count is the dependent variable. The right figure in Figure \ref{fig:Interaction_Effects} visualizes this relationship. Different from the left figure in Figure \ref{fig:Interaction_Effects}, we observe in the right figure that project performance is the highest when social capital losses are at the lowest levels and network density is at higher level. One explanation for this may be about the nature of the collaboration network: a dense collaboration network implies more collaboration among members to work on group tasks, thus promoting trust, reciprocity norms and routines in the group, which has potentially positive effect on group performance. We also observe that as social capital losses increase from low to moderate levels, the slope of the line becomes steeper when density is high than that when density is low. One explanation may be: Dense networks indicate more collaborations among members, so dense networks are more susceptible to social capital losses. Moreover, the overall network density in this study is not very high as we see from Table \ref{Tab:Descriptive_stats}, there is less redundancy of social ties that would make the networks tolerant to disruptions. The figure shows that the negative curvilinear relationship is more pronounced when network density is high. Thus, \textbf{Hc2} is partially supported.
\section{Measures}
To investigate the research questions, we explore the relationship between the performance of online voluntary groups, membership turnover, and social capital loss related measures. The following introduces the dependent, independent and control measures used in this study.

\subsection{Dependent Variable}
Previous work on Wikipedia generally measures group performance as the amount of work done by members (i.e., the total number of edits to Wikipedia article pages by members). Admittedly, this is a very raw proxy of contributions by members to Wikipedia, and it generally neglects the quality of the contributions. We further calculate the edit longevity of each edit using WikiTrust software by \cite{Adler2007}, which computes the value of each contribution by combining its quality and quantity.

\subsection{Independent Variables}
\textbf{Social Capital Losses (SC Losses)}. Social capital theory has been developed to explain the value inherent in social relationships. Social capital is created when relationships facilitate reciprocal action among people \citep{Coleman1988}. Although there is no universal and precise definition for network social capital (e.g., network closure by \cite{Coleman1988} vs structural holes by \cite{Burt1992} as social capital), social capital can be broadly defined as the benefits that network members secure from their memberships in social networks or other social structures \citep{Portes1998}. These studies further contend that organizational social capital can improve performance by enhancing commitment, increasing flexibility, and promoting knowledge sharing and information diffusion that fosters intellectual capital \citep{Coleman1988,Burt1992,Shaw2005}.

If social capital at the collective level is generated when connections facilitate instrumental action among people \citep{Coleman1988}, it is also lost when the connections among people are dissolved \citep{Burt1992,Shaw2005}. These connections, which are generally referred to as structural holes by \cite{Burt1992}, play an essential role in facilitating resources exchange and knowledge management for network members. Researchers suggest that turnover among core members who occupy key network positions should be more damaging to organizational performance than withdrawal among members who occupy less central network positions \citep{Shaw2005}. We expect that in online communities, social capital losses due to member turnover should have similar impact on group performance.

As with other researchers, we used ``betweenness centrality'' by \cite{Freeman1979} to measure the extent to which members occupied structurally advantageous positions (i.e., structural hole bridges) in the collaboration network of a WikiProject. Following \cite{Shaw2005}, we calculate social capital losses as a ratio: the average betweenness scores of the leavers divided by the average betweenness scores of all project members.

\textbf{Turnover rate}. Measured as the percentage of members who were active in previous quarter and not active in current quarter. We consider a member being active in a quarter if and only if the member made at least one edit to articles within project scope.

\textbf{Network Density}. This variable measures the proportion of existing connections in the network to the number of possible pairwise combinations of members, and takes value from zero to one, with larger values indicating increasing density. We include this measure because previous work found that in case of social capital losses due to member turnover, a dense network with experienced members and the abundance of redundant social ties would be more tolerant to network disruptions or gaps created by turnovers \citep{Shaw2005}.

\subsection{Control Variables}
\textbf{Quarter}. This variable indexes the quarters in which project-related measures are collected: starting with quarter 0 from the time the project is created, till the last quarter of study periods. The coefficient of this variable indicates the dynamics of project performance over time.

\textbf{Project creation time (A proxy of project age)}. Measured as the number of quarters (90-day periods) from the baseline timestamp (the timestamp that the first WikiProject was created) to the creation timestamp of a project. \cite{Chen2010} found that the creation time of a project has negative influence on its performance. They explained that due to the growth of the number of projects and participants over time, projects created later may face a  more different environment than those created earlier. In this work, we also include this variable to control for the effect.

\textbf{Project scope}. Measured as the accumulated number of articles that are tagged by a project template up to the current quarter.  Most changes reflect new articles being added to the project's scope.

\textbf{Project size}. Measured as the number of project members and active participants during a quarter.

\textbf{Edit activity in project talk pages (Discussion topics)}. In online communities, members generally rely on discussion pages to communicate with others, ask for help and support, reach consensus on controversial issues, and make collective decisions regarding rules and regulations. A large amount of content posted on project-related talk pages is beneficial for the community in terms of enabling participants to arrive at a general understanding or get help for specific questions. \cite{Qin2012} found that the number of discussion topics is positive and significant related to project efficiency in Wikipedia. We calculated the amount of group communication as the total number of discussion topics recorded in the edit history of project-related talk pages in a quarter.

\textbf{Mean membership tenure (Mean Tenure)}. The average membership tenure of a WikiProject is calculated as the sum of the membership tenure of its members divided by the number of members in a quarter.

Following \cite{Chen2010}, we also measured membership tenure as the amount of time a member has been active in Wikipedia. Specifically, our measure of membership tenure consists of two parts: membership tenure before and after joining a WikiProject. The previous tenure of a member is calculated as the number of days between the timestamp that the user made the first edit in Wikipedia and the timestamp that this user joined a WikiProject. For a specific quarter, for any month, if a user made at least one edit to any project related pages, we calculated the monthly project tenure of this user as the number of days in that month. Then for each project member, we accumulated his previous tenure and monthly project tenure up to the current quarter to obtain his overall membership tenure in Wikipedia.

\textbf{Level of controversy}. The controversy of project topics may have impact on project performance in that it takes time and effort for project members to discuss and reach consensus on controversial issues. Following \cite{Chen2010}, we also include this variable to control for these effects and to separate them from the main effects caused by social capital losses. This variable is measured as the percentage of reverted edits to all articles within project scope during a quarter, normalized by the overall percentage of reverts in Wikipedia in the same time period.

\textbf{Tenure diversity}. In online communities like Wikipedia, it is often the case that members who have been active for a long time tend to be more experienced than new users. These active members play a fundamental role in the community in terms of spreading knowledge, information and experience across the whole community. High tenure diversity indicates high variability among project members in the time they have spent committing to group tasks and in the experience they have accumulated \citep{Chen2010}. Studies about open collaboration in online communities found that members with different tenure are more likely to perform different kinds of tasks \citep{Bryant2005}, so projects with a mix of newcomers and old-timers may enjoy better task distribution.

The coefficient of variation has been widely used in management science literature to measure tenure diversity \cite{Chen2010}, because the potential benefits and conflict due to tenure are derived from the spread of members' experience and knowledge relative to a project's mean tenure \citep{Harrison2007}. Following this convention, we measured tenure diversity using the coefficient of variation of tenure of all project members.

\subsection{Hypotheses}
To test the effect of turnover rate, we make the first hypothesis:

\textbf{Ha} \emph{There is a negative relationship between a project's turnover rate and its performance.}

Previous work has suggested curvilinear relationship between social capital losses and organizational performance \citep{Shaw2005}. Motivated by these studies, we develop the following hypothesis regarding the effect of social capital losses:

\textbf{Hb} \emph{Social capital losses of a project due to member turnover relates in a curvilinear fashion to its performance, strongly declining performance with moderate levels of social capital loss but increasing performance at higher levels of social capital loss.}

\citeauthor{Shaw2005} found that turnover rate mediates the curvilinear relationship between social capital losses and organizational performance. Following \cite{Shaw2005}, we develop the following hypothesis:

\textbf{Hc1} \emph{Social capital losses and turnover rate interact in predicting project performance: the curvilinear relationship between social capital losses and performance is stronger when turnover rate is low.}

\cite{Shaw2005} suggested that in case of social capital losses, a dense network with the abundance of redundant social ties would be more tolerant to network disruptions or gaps created by turnovers. However, they found no support for their predictions regarding the mediated effect of density on the relation between social capital losses and organizational performance when density is low. They further suggested that it would be beneficial for future research to explore the conditions under which social capital losses in dense network structures are damaging to organizational performance \citep{Shaw2005}. Following this suggestion, we make the following hypothesis:

\textbf{Hc2} \emph{Social capital losses and network density interact in predicting project performance: the curvilinear relationship between social capital losses and performance is more pronounced when network density is high.}
\section{Membership Turnover and Performance}
There has been substantial work studying the effect of turnover on performance in traditional organizations, but perspectives on this relationship vary widely. The most dominant view suggests that turnover has a negative impact on performance, because the turnover of members can incur replacement costs, disrupt the social network, or weaken the knowledge resources of the organization \citep{Huselid1995}. A second argument indicates that in certain situations turnover may benefit organizations since departing employees are often those most dissatisfied with the current organization, so those who remain behind enjoy better working conditions and performance \citep{Krackhardt1985}. A third perspective suggests that moderate levels of turnover lead to the best organizational performance \citep{Abelson1984} in terms of creating opportunities for organizations to access new skills and knowledge through the influx of new employees \citep{Madsen2003}. In their empirical study on 38 locations of a restaurant chain, \cite{Shaw2005} found that employee turnover rate moderates the curvilinear relationship between social capital losses and performance. Despite the fact that online communities (e.g., Wikipedia) generally experience considerable membership turnover, the effects of turnover on collaborative outcomes are not well understood.

Because online communities rely on the contributions of voluntary members to survive and succeed, member turnover can have significant effects on collaborative activities in terms of resource availability and the health of a community \citep{Ransbotham2011,Wang2011}. Some studies have approached the issue from the perspective of member retention, and assumed that such retention is important to community success and survival \citep{Joyce2006}. \cite{Faraj2011} suggested that the fluidity of members can bring opportunities for knowledge collaboration when managed appropriately. By experiments on 2,065 featured articles from Wikipedia, \cite{Ransbotham2011} found a curvilinear relationship between the turnover of Wikipedia editors and the quality of an article. Specifically, they discovered that a Wikipedia article edited by experienced editors is more likely to be of higher quality up to an optimal level of experience, after which the average experience of editors decreases the quality of the article (by demoting it from FA status to lower quality status). \cite{Wang2011} provided a framework to systematically examine the relationship between member turnover and the health of a community, where community health is measured as the content volume, traffic, responsiveness, interactivity of the community. However, the authors haven't provided empirical results to evaluate their hypothesis.

More recently, \cite{Zanetti2012} studied the evolution of social structual in open source software communities along multiple dimensions, such as the cohesiveness of the communities, the distribution of responsibilities and the resilience against membership turnover in the community. They concluded that their preliminary results are a promising step towards the definition of suitable, potentially multi-dimensional resilience and risk indicators for open source software communities. However, this study has some limitations in that it did not take into account community performance indicators.
\section{Acknowledgements}

This work is supported by Science Foundation Ireland (SFI) under Grant Number SFI/12/RC/2289 (Insight Centre). Xiangju Qin is funded by University College Dublin and China Scholarship Council (UCD-CSC Scholarship Scheme 2011).

\bibliographystyle{aaai_bib}

\section{Conclusion}
We have empirically examined the impact of membership turnover in online groups on its productivity. The results show that membership turnover has significant negative effect on group outcomes in Wikipedia, and that social capital losses through member turnover are associated with group productivity in a negative curvilinear fashion. Our results show that the loss of social capital in collaboration networks can explain significant amount of variation in productivity for WikiProjects. The results contribute to the existing literature that investigates the relationship between social capital losses and group performance (e.g., \cite{Huselid1995,Abelson1984,Shaw2005,Ransbotham2011}) in conventional organizations and online communities. The results also support the mediation of turnover rate and network density on the relationship between social capital losses and group productivity.

Previous studies have suggested that editors with different tenure are likely to perform different types of tasks \citep{Bryant2005}, and that groups consisting of members with diversified tenure generally enjoy better task distribution and group performance \citep{Chen2010}. Similarly, our exploration of the dataset reveals that projects with low levels of social capital losses and turnover rate generally enjoy better task distribution and group outcomes. It will be very interesting to investigate the impact of task distribution among members on group performance and to study the evolution of user behaviours in online communities. Furthermore, we observe that project members denote substantial amount of time to edit non main namespaces such as article talk pages and user talk pages. This study only considers social capital losses in collaboration networks, it will be worthwhile to take into account social capital losses in communication networks for WikiProjects and in article talk networks and user talk networks.
\section{Discussion}
We have found that there is a negative curvilinear relationship between social capital losses and group productivity in WikiProjects -- as social capital losses increases from very low level to moderate level, the amount of work done by project members declines; after the moderate level, with any further increased in social capital losses from turnover, the amount of work done by project members increases.

\begin{figure}[!htb]
\baselineskip=12pt
{\fontsize{10.0pt}{10.0pt}\selectfont
\begin{center}
  \subfloat{\includegraphics[width=0.90\textwidth]{./figs/Edit_Distribution_for_WP_Medicine}}\quad
  \subfloat{\includegraphics[width=0.90\textwidth]{./figs/Edit_Distribution_for_WP_Unionism_In_Ireland}}\\
\caption{Evolution of Edit Distribution for WP Medicine and WP Unionism in Ireland.}
\label{fig:Edit_Distribution_Exploration}
\end{center}
}
\end{figure}
To further understand the characteristics of quarterly observations that locate at different areas (specifically, the far left, middle and top right area) of the curve in Figure \ref{fig:sc_losses_productivity}, we explore the dataset in more details by tracking the evolution of independent variables and average task distribution over quarters. Following other studies, we also quantify different types of tasks as edits to different types of pages within Wikipedia. The file system of Wikipedia is subdivided into ``namespaces"\footnote{http://en.wikipedia.org/wiki/Wikipedia:Namespace} which represent general categories of pages based on their function. Average task distribution is calculated as the average number of edits to a specific namespace by project members in a quarter. We observe that healthy WikiProjects generally experience lower levels of member turnover and social capital losses, thus enjoy better group outcomes and better task distribution, and tend to locate somewhere between the far left and middle areas of the curve in Figure \ref{fig:sc_losses_productivity}; while unhealthy WikiProjects generally experience more fluctuation in member turnover and social capital losses, have extremely unbalanced task distribution, and have their quarterly observations distributed over the three areas of the curve in Figure \ref{fig:sc_losses_productivity}.
\begin{figure}[!htb]
\baselineskip=12pt
{\fontsize{10.0pt}{10.0pt}\selectfont
\begin{center}
  \subfloat{\includegraphics[width=0.90\textwidth]{./figs/Evolution_of_Independent_Variables_for_WP_Medicine}}\quad
  \subfloat{\includegraphics[width=0.90\textwidth]{./figs/Evolution_of_Independent_Variables_for_WP_Unionism_In_Ireland}}\\
\caption{Evolution of Independent Variables for WP Medicine and WP Unionism in Ireland.}
\label{fig:Independent_Variable_Exploration}
\end{center}
}
\end{figure}

We found that WikiProject Medicine is a very healthy project with all its observations located at the far left region of the curve, while WikiProject Unionism in Ireland is a less healthy project. Figure \ref{fig:Edit_Distribution_Exploration} and Figure \ref{fig:Independent_Variable_Exploration} present the evolution of edit distribution and independent variables for the two projects, respectively. Because article edits generally account for more that 50\% of members' activity, we omitted it from Figure \ref{fig:Edit_Distribution_Exploration} to improve readability of the graph. The two figures in Figure \ref{fig:Edit_Distribution_Exploration} shows a substantial difference among their average edit distribution: WikiProject Medicine enjoys better and more balanced task distribution than WikiProject Unionism in Ireland, with the members of the former making edits across a range of namespaces each quarter. The figures in Figure \ref{fig:Independent_Variable_Exploration} reveals that WikiProject Unionism in Ireland experiences substantial fluctuation in its member turnover and social capital losses, while WikiProject Medicine has a more stable evolution in its independent variables.
\section{Introduction}
With the popularity of Web 2.0, recent years have witnessed a growing population of online communities which rely on contributions from online volunteers to build knowledge and software artifacts. Despite the success of a few communities, such as Linux, Apache, Wikipedia and OpenStreetMap, many of them fail to generate desired outcomes. Many of these failures are due to the intrinsic characterstics of open collaboration in online communities, namely, high levels of member withdrawal \citep{Faraj2011,Ransbotham2011}. Even in successful online communities, such as the English version of Wikipedia, high churn in membership is still the norm, with 60\% of registered users staying only a day \citep{Panciera2009,Dabbish2012}. Figure \ref{fig:yearly_active_editors} presents the statistics of yearly active registered editors on English Wikipedia from its inception. Figure \ref{fig:yearly_active_editors} shows that each year the number of new editors dominates the amount of active editors, suggesting that Wikipedia experiences high level of membership turnover.
\begin{figure}[!htb]
\baselineskip=12pt
{\fontsize{10.0pt}{10.0pt}\selectfont
\begin{center}
  \subfloat{\includegraphics[width=0.98\textwidth]{./figs/Statistics_of_Yearly_Active_Users_in_English_Wikipedia_2001_2013}}\\
\caption{Statistics of Yearly Active Editors in English Wikipedia from 2001 to 2013. The data for 2013 was only till August 5, 2013.}
\label{fig:yearly_active_editors}
\end{center}
}
\end{figure}

In traditional organizations, the cost of leaving a job can be extremely high in terms of sacrificing material or psychological benefits, such as giving up colleagues, interesting projects, corporate stock and pension benefits \citep{Mitchell2001}. Different from traditional organizations, in online communities, without committing to any tasks, projects, or conversations, the barriers to entry and exit are very low, each participant is free to join and leave \citep{Ransbotham2011}. Joining an online group can be as easy as filling in a form or writing a profile \citep{Dabbish2012}, leaving an online group is even easier by stopping contributions or showing no activities in the community. For online volunteers, leaving an online community generally incurs little cost (except losing opportunity to learn from peers). While for an online community, member withdrawal can have a significant influence on its functionality: membership turnover may improve group performance by bringing in novel skills and expertise, but it may also threaten the cognitive structures and processes that are so useful for expertise coordination \citep{Lewis2007,Faraj2011}, and inevitably disrupt routines and established social ties and further reduce its social capital \citep{Shaw2005}.

High membership turnover in online communities has attracted much attention from researchers to study the influence of turnover on community health. The most dominant view suggests that membership turnover is disadvantageous to effective collaboration, and the ability to engage and retain members represents a key aspect of success (e.g.,\cite{Arguello2006,Butler2001}). Those who leave the community, take with them not only the unique knowledge and insight, but also the experience and social relationships they have gained and established through participation. Therefore, these studies suggest that, those departures diminish the resources available to the community and may threaten its very sustainability. On the other hand, some research suggests that the unique capabilities of Web 2.0 techniques could help mitigate the negative effects of turnover (e.g.,\cite{Kane2007}). For example, platforms based on Web 2.0 techniques are typically equipped with functions to preserve all previous contributions by past members in an organized and searchable manner, so as to facilitate the utilization of past contributions for future community members as needed \citep{Kane2009,Wagner2006}. Different from previous studies, \cite{Ransbotham2011} suggested that moderate levels of turnover are best for collaboration in online communities, such that the influx of novel knowledge exceeds the loss of existing knowledge held by departing members. While these studies shed light on the relationship between turnover and performance in the online scenario, a major limitation is that they fail to consider social capital loss through member turnover and its impact on the functionality of communities.

Despite the success as a means for knowledge sharing and collaboration, little is known about the mechanism behind Web 2.0 platforms from the perspective of social network analysis. The social network approach provides a unique perspective to study the evolution of online communities over time, and to study the resilience of social networks against node removal (i.e., member drop-out) in these platforms. In this study, we take a social network approach to investigate the relationship between member turnover, social capital losses and group performance in WikiProjects. We are interested in the following questions: Does the drop-out of members in different network positions have the same effect on group performance? How does social capital loss due to departing members influence group performance? Is there consistency across the evolution of online groups? Overall, the eventual goal of this study is the provision of multi-dimensional indicators related to the health and performance of online communities, which provides insight into the management and evaluation of these communities.

The rest of this paper is organized as follows. The next section provides a brief review of related work. In Section 3, we explain network measures and project characteristics related variables, and develop hypotheses. Next, we discuss data collection and model specification. Section 5 presents the results, followed by discussion and conclusion.

redpajama_set_name: RedPajamaArXiv


text:
ACCEPTED

#### According to
Index Fungorum

#### Published in
Mycotaxon 16(1): 49 (1982)

#### Original name
Pseudocercospora vitigena J.M. Yen, A.K. Kar & B.K. Das

### Remarks
null

redpajama_set_name: RedPajamaGithub


text:
by Nurture Nature Now | May 9, 2016 | Animal Rights | 0 comments
Those are the words of neuroscientist Gregory Burns. Burns wrote those words in a New York Times article after having spent two years studying the brain activity of calm, unrestrained dogs in MRI scanners. After all that time, his "one inescapable conclusion is this: dogs are people, too."
Burns and his colleagues wanted to apply modern neuroscience to see what they could learn about what dogs were thinking and feeling. With this as their task, they adopted a bit of a different approach to studying the dogs than is often taken in animal research: "We used only positive training methods. No sedation. No restraints. If the dogs didn't want to be in the M.R.I. scanner, they could leave. Same as any human volunteer."
Dogs were gradually trained to feel comfortable sitting still in the M.R.I machines, wearing ear protection to protect them from the noise the scanners generate. They tested how their furry volunteers responded neurologically to hand signals indicating food, and to the scent of familiar humans and dogs.
The results should hardly surprise anyone who has spent much time with dogs: they found that the dog brains were responding much the way human brains do when anticipating reward or experience love or affection. Specifically, they looked at activity in the region known as the caudate nucleus, an area in humans which is recognized for playing a central role in memory and emotion. As the author notes:
Specific parts of the caudate stand out for their consistent activation to many things that humans enjoy. Caudate activation is so consistent that under the right circumstances, it can predict our preferences for food, music and even beauty.
In dogs, we found that activity in the caudate increased in response to hand signals indicating food. The caudate also activated to the smells of familiar humans. And in preliminary tests, it activated to the return of an owner who had momentarily stepped out of view. Do these findings prove that dogs love us? Not quite. But many of the same things that activate the human caudate, which are associated with positive emotions, also activate the dog caudate. Neuroscientists call this a functional homology, and it may be an indication of canine emotions.
This study, and others like it, should fundamentally alter the way that we, as a society, interact not only with dogs but with all other sentient beings with whom we share the planet. As the author points out, much of the research done on animal cognition or emotion is based purely on behaviorism — that is to say, on observations of how an animal acts or reacts in certain contexts.
While it's important that we pay attention to how animals are actually acting (they communicate so much through their behavior, after all), this kind of neurological research shows us how animal studies are often lacking. Scientists, afraid of being accused of anthropomorphism, frequently have a tendency to avoid ascribing emotional states to their test subjects, describing their behavior instead in mechanistic or "neutral" terms. This is perhaps not surprising, considering that much of the research into animal behavior is specifically targetted towards "production animals" and is funded and influenced by the animal farming industry.
Studies that look at the actual brain activity in animals reminds us that, while we may be able to better understand and communicate our own emotional states, non-human animals are also capable of experiencing these same emotions.
And why shouldn't they? Our emotional states are so basic to our functioning and our existence, so central to what we are as organisms. They are obviously deeply rooted in our biological background. Why should we not expect that other creatures which have evolved to live on the same planet with us would have the capacity for similar cognitive states?
The answer to that is, probably, that it is easier for us to forgive ourselves and to justify our treatment of other beings by reassuring ourselves that we alone possess the capacity for subjective experience, consciousness, sentience, a soul, or however else we want to talk about whatever it is that makes us more than mere things: that which makes us not human, but people.
As Burns says in the NY Times piece: "It has been easy to sidestep the difficult questions about animal sentience and emotions because they have been unanswerable." Well, it's becoming increasingly difficult to ignore those questions.
Science is now confirming what we should all known all along: we are not the only animals on this Earth with the capacity for emotions. We aren't the only ones who care, who want, who fear, who hurt, and who play. What sets us apart is not our ability to feel — indeed, as a species we seem to be capable of remarkable displays of callousness. What sets us apart is our ability adapt our environment and to shape the world around us.
Too often this unique human characteristic is destructive when it could be life-affirming. Too often it is extractive when it could be creative, exploitative when it could be transformative. When we stop treating other creatures and the planet itself as things to be used up and begin instead to treat them with respect and dignity, then we can create a world that is better for all people — both the furry and the bald.
That's our vision. See our Resources and Ways to Help pages for more information on how you can contribute towards making the world a safer and more comfortable place for all people.

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I could not have dreamed of a better person to sell my home than Blake. He knew how to price it to sell quickly and was involved every step of the way. When we had a little hiccup with the appraisal, Blake made me feel confident he knew the best way to solve the problem. And he did! On top of all his selling expertise, he's a funny guy who's fun to work with! Loved my entire experience.


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SuperBox works wonders as a static image gallery, which you can click to reveal a full version of the image. Each image in the demo is the same size, but SuperBox supports any image size.
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I laugh more at the Guide to... ebooks than anything else on my ipod.
Ten promotional episodes offer over an hour happy listening as Ricky Gervais and Stephen Merchant coax and provoke Karl Pilkington.
The copyright of the article Podcast Review: The Ricky Gervais Guide Promotion Episodes in Audiobooks/Ebooks is owned by Alex Sharp. Permission to republish Podcast Review: The Ricky Gervais Guide Promotion Episodes in print or online must be granted by the author in writing.


When Kelly Stephans floated the idea of a block party to neighbor Sally Martin, she didn't know the idea would soon go viral. Word of mouth spread and soon more neighbors caught Kelly's enthusiasm. From the professional graphics on the flyer to the professional chef who volunteered to oversee a pig roast, the party seemed to be an idea whose time had come.
The enthusiasm of the planning team was contagious and everyone had something fun to do, regardless of age or ability. Games, contests, and prizes were offered. A Malkin Penn's jersey was one of several auction prizes and services donated by neighbors.
A storm passed over just before dinner, quickly drenching everyone who didn't get to shelter. Folks went home to change into dry clothes and came back to party on. The rain created a temporary mud puddle in one yard which instantly attracted a youngster like flies to the porch light. Those who held back from the party because of the rain did venture out to mingle and help devour the potluck of salads, hot casseroles, desserts, burgers 'n dogs, and pulled pork.
Many of the sixty-some neighbors found themselves in conversations with people who lived only a few doors down for decades, but had never officially met. Halloween seems to be the one time of year neighbors get around to meet and greet. The kids make sure visits are kept short that night, however, and until now most of the neighbors had a fairly small circle of people they could greet by name. If you were shy about meeting new people, there were several well-behaved dogs to admire and that always helps break the ice.
The homes in the McCandless neighborhood, locally referred to as the "Indian Village" for it's street names, is a mix of 1970's split entry homes with generous yards and older brick houses. There is a wide age-range of residents, with the kids spread out from infants to older teens. As established families age and downsize, younger families are beginning to move in.
The demographics of the North Allegheny School District is also changing as more families from other cultures move into the highly desirable district. The Indian Village began to see this shift about five years ago when a young professional family moved here from China. They have been warmly embraced by their neighbors.
The event will undoubtedly have a positive impact on the community's already strong feeling of safety; when neighbors know one another the community is more secure. Before the party, many residents would not have recognized each other if they were standing in line at the grocery store. The organizers of the "first annual" party have helped change that, and are already talking about how next year's event will be even more amazing.
Featured picture includes the ladies of the planning commitee. Back row L-R: Mary Leitch, Debbie Goral, Kelly Stephans, front row L-R: Maureen Iannessa, Sally Martin, Carol Barth, Jennifer Clutter.
Full credit for the party goes to all of the neighbors on the planning committee. They are Kelly and Mike Stephans, Debbie and Tom Goral, Carol and Wayne Barthe, Maureen and Vince Iannessa, Sally and Jim Martin, Jennifer Clutter, Charlie Fox, Mary and Roy Leitch, and Heather Henkel.


JAKE: YOU KILLED DIRK AND ROXYS BRO AND MOM RESPECTIVELY!
JAKE: OR YOU WILL LATER I THINK AND I CANNOT LET THAT HAPPEN!
JAKE: I WONT LET YOU TURN MY PLANET INTO WATERWORLD!
JAKE: THAT MOVIE WAS GREAT! BUT NOT *THAT* GREAT!
JAKE: I CANT LET YOU EXPLOIT YOUR BAKED GOODS EMPIRE TO MASSACRE THE HUMAN RACE!
JAKE: OVER MY DEAD BODY AM I GONNA LET YOU STICK A PAIR OF STINKIN JUGGALOS IN THE WHITEHOUSE!
ARANEA: Augh, why does this all have to 8e so complicated to explain!!!!!!!!


text:
Flag change- John Key comes across as a cheap and nasty con man
The prevailing political mood of the "flag change panel" is as you would expect progressive. Julie Christie, Beatrice Faumina, Rod Drury, and a couple of the mandatory drop kicks from left wing academia. Maybe two Conservatives in Rhys Jones and Brian Lochore.
However seeing they all agreed to sit on the committee, then one must assume they're all for the change, given the first task is to decide what the potential replacement design will be. So its a farce, and it always has been a farce since John Key announced there would be not one but two referenda with the first one to choose the replacement design.
The choosing of two referenda as well as being just a cheap artifice is also a gross misuse of taxpayer funds. Furthermore, it is a clear breach of the guidelines wherein it was specified quite clearly that the committee should not commit to any deed that would pre-suppose the change.
Bill English reiterates that today- "Each member has committed to undertake the flag consideration process carefully, respectfully and with no presumption in favour of change."
I repeat the very obvious question this declaration raises. How is it possible to keep to this commitment when the first issue under discussion is what the replacement design will be?
This is such a disgustingly dishonest farce.
Leaving aside the cost, which is all up estimated at $25.7 million. $17.3 million of this is the two referenda. Half of this could be saved and probably half of the remainder too by holding a referendum right now on whether any change is necessary or desirable.
Not only would John Key be doing the right thing, he would be saving the taxpayer about $15 million or more in unnecessary expenditure. No second referendum and no further consultation being necessary.
However the truth is Key wants to spend the whole $25.7 million because really the purpose of the first part of the operation is a public brainwashing session designed to implant the idea of change in the public's mind. To pave the way for the second referendum approving the change.
Just a cheap and nasty dishonest confidence trick on NZ voters. We've seen other instances of Key's duplicity lately but they're nothing compared to the deceit behind this operation. I've noticed Nat party members are too frightened to even speak out on this issue, such is the intimidating power of Key's inner circle within the National Party.
All for what? John Key's vain desire for some kind of political legacy? If it was up to me, he'd be paying for the whole damn farce out of his own pocket. If I couldn't stop the whole damn slick tainted duplicitous process in its tracks that is.
February 26, 2015 in Culture, NZ Politics. Tags: Confidence trick, Flag change, John Key
Bill English talking nonsense on flag change referenda
← How the left wing MSM lies by omission- a stark example
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11 thoughts on "Flag change- John Key comes across as a cheap and nasty con man"
In the past we would have had MP's who would come out and speak against such a farce and challenge the leader publicly. And I mean National MP's.
Not one MP has the guts to ever challenge anything anymore.The worst bunch of National MP's ever.It is not even worth going to see your MP if you feel strongly about an issue.Constituents are a nuisance.
Well said. Totally agree with all of the above.
Thank you Peter. Notice how the Labour Party are silent on this issue? Because its exactly what would be happening if they were in power.
How about the first job of the committee is to commission a series of polls to see if there is any appetite from the electorate for a flag change.
There recommendation may then be, that it is a waste of time to waste further resources on designing a flag that is unwanted.
Would any new flag law also ban the flying of the old flag. If so would it also ban the flying of so called "independence" flags.
Or maybe like Wanganui you can choose which flag you want to fly.
I suspect that all the committee was polled on their willingness to go along with the process and are probably being paid accordingly, why woudl the turkeys vote for an early Christmas.
I think the members of the committee need to consider the potential damage to their own credibility and integrity being part of a farcical stitch up like this.
This lot have been brought and paid for.
Don the Kiwi says:
Good to see you back in action Red. 🙂
Thanks Don. We all must do what ever little bit we can.
Whata travesty. I so agree with what you said, Key;s inner circle is sinister and don't like freedom of opinion or speech. Key is a leader who is totally morally bankrupt. He would sell his soul for the sake of his ego. What sheer arrogance. National MPs treat the people with utter, bare-faced contempt. Labour are actually at least human!!
Harriet says:
From the outset Key was telling porkies, "I often end up being seated under the Australian flag." Maybe so, but what were his staff and foreign affairs doing about the placement of the wrong flag when he was overseas? – nothing! Yet it's what they are paid to do! Even rockbands can get the black jelly beans removed from the rest while on tour, while Key's well paid staff couldn't give a stuff about the NZ PM and the integrety of the country while overseas.
Then there is "We need a flag that is known as well as Canada's flag is." — Why? — Canada wouldn't export anymore because of it, and they also have a huge tourism budget. Canada's flag doesn't do anything more for Canada than what their previous flag did, it is simply now more noticable than other countries flags.
Also, if every second country does the same and changes their flag to a logo like Canada and NZ – then we are back at square one – with a mostly indistinguishable flag.
Key has not got rid of the problem where Maori are taking more than they are entitled to from the rectification process of past grievances, so he will now find 'pakeha NZ' clinging to the current flag like Americans cling to their guns.
For Key it's all just a vanity project anyway.
Ashley Schaeffer says:
There are so many other worthwhile changes that Key could be expending his political capital on, not least of which would be taking an axe to taxpayer funded media outlets that are havens for commie hacks, or any other number of government quangos pissing taxpayer dollars down the drain.
I have a hunch that the net result of the flag issue and getting involved in the murky middle east will be Key and National kissing goodbye to a fourth term.


text:
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text:
Fentress Designs Norwegian Chancery in Washington D.C. as a Homage to National History
09:00 - 5 October, 2018
by Lindsay Duddy
Courtesy of Fentress Architects
Fentress Architects has revealed their design for the expansion of the Norwegian Chancery in Washington D.C. A prominent new addition to the embassy's Washington D.C. campus. The scheme expands the architectural language of the existing embassy buildings, embracing contemporary design techniques within the context of traditional bureaucratic architecture.
Fentress' design integrates materials of Norwegian cultural significance as prominent features of the façade. The use of Norwegian spruce timber, Oppdal stone, and patinated copper pay homage to the country's traditions in shipbuilding and woodworking, as well as their abundance of natural resources.
The 30,000 square-foot addition was designed to ignite an intriguing dialogue between the new and the old. Most importantly, the contrast between Fentress' vision and the existing neo-classical buildings was meant to create a harmonious dichotomy.
While providing significant functional, accessibility, and sustainability upgrades, our architecture will make Norway's rich heritage visible on one of the most culturally significant streets in the United States and the world.
-Steve White, Principal-in-Charge, Fentress
The Chancery's curvilinear copper mansard roof encases the entryway while delicately intersecting with the existing garden's stone wall and connecting the chancery, embassy, and residence inside. The portal welcomes those who enter, guiding visitors into the new courtyard containing an extensive garden, outdoor seating, and a covered gathering space.
Best known for the Denver International Airport, Fentress has established a vast portfolio of design experience. Similar to airports, security and circulation play a key role in the design of an embassy building. A highly-trafficked structure will see visitors, administrators, and political officials pass through the chancery, gaining a glimpse of Norwegian culture and hospitality in America's capital.
News via: Fentress Architects
Lindsay Duddy
News Architecture News Washington DCEmbassyFentress Architects
Cite: Lindsay Duddy. "Fentress Designs Norwegian Chancery in Washington D.C. as a Homage to National History" 05 Oct 2018. ArchDaily. Accessed . <https://www.archdaily.com/903137/fentress-designs-norwegian-chancery-in-washington-dc-as-a-homage-to-national-history/> ISSN 0719-8884
Fentress 建筑事务所设计华盛顿特区的挪威法院,向国家历史致敬


text:
package com.bitdecay.jump.level;

import com.bitdecay.jump.BitBody;
import com.bitdecay.jump.geom.BitPointInt;
import com.bitdecay.jump.geom.BitRectangle;

/**
 * Created by Monday on 11/23/2015.
 */
public class TriggerObject extends LevelObject {
    public LevelObject triggerer;
    public LevelObject triggeree;

    public TriggerObject() {
        // Here for JSON
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    public TriggerObject(LevelObject triggerer, LevelObject triggeree) {
        super(new BitRectangle(triggerer.rect.center(), triggeree.rect.center()));
        if (triggerer.uuid.equals(triggeree.uuid)) {
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            float smallestAxis = Math.min(triggeree.rect.getWidth(), triggeree.rect.getHeight());
            rect = new BitRectangle(triggeree.rect.xy.plus(0, triggeree.rect.getHeight()), -smallestAxis, smallestAxis);
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        this.triggerer = triggerer;
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    @Override
    public BitBody buildBody() {
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    @Override
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    @Override
    public boolean selects(BitPointInt point) {
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    @Override
    public boolean selects(BitRectangle selectionRect) {
        return selectionRect.contains(rect.xy);
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}


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text:
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Subject: CAINE 3.0 Review – Linux Forensics
CAINE is a well-known specialised Linux distribution focusing on penetration testing. With its latest 3.0 release, it updates itself to the Ubuntu 12.04 base and adds a host of new tools
http://www.linuxuser.co.uk/reviews/caine-3-0-review-linux-forensics
Subject: Set Up DKIM (DomainKeys Identified Mail) Working With Postfix On CentOS Using OpenDKIM
This tutorial shows how to get DKIM working on a CentOS box running Postfix using OpenDKIM. I'll also cover some simple troubleshooting tips and advice for future upgrades on your OpenDKIM installation.
http://www.howtoforge.com/set-up-dkim-domainkeys-identified-mail-working-with-postfix-on-centos-using-opendkim
Subject: Netflix Comes To Linux Via Silverlight On Patched Wine
Netflix video streaming is now available on Linux through the use of Wine. When running a specially patched version of Wine in conjunction with the Microsoft Windows versions of Firefox and Microsoft Silverlight, Netflix can now do Internet video streaming to the Linux desktop...
http://www.phoronix.com/vr.php?view=MTIyOTc
Subject: With increased revenue, Mozilla sets its sights on mobile
In a statement on her blog, Mitchell Baker, Chair of the Mozilla Foundation, said that the organisation has its sights firmly set on the mobile space for 2013. The goal is to duplicate the organisation's success with Firefox on the desktop on mobile phones and tablets. "We're building these products now. We have the financial resources to support these efforts," Baker said. The product in question is Firefox OS, which Mozilla's developers have been working on for the better part of a year. Since Mozilla has had difficulty in bringing full versions of Firefox to iOS, Windows Phone and Windows 8 on tablets, it is now building its own ecosystem based on web technologies including HTML5 and JavaScript.
http://www.h-online.com/open/news/item/With-increased-revenue-Mozilla-sets-its-sights-on-mobile-1751219.html/from/rss
Subject: Humble Bundle for Android #4 adds 5 games
Great news! 5 games have been added to the Humble Bundle for Android #4!
http://ubuntugamingproject.blogspot.it/2012/11/humble-bundle-for-android-4-adds-5-games.html
Subject: EXT4 File-System Tuning Benchmarks
Following last month's Btrfs file-system tuning benchmarks, in this article are a similar set of tests when stressing the EXT4 file-system with its various performance-related mount options. Here are a number of EXT4 benchmarks from Ubuntu 12.10 with different mount option configurations.
http://www.phoronix.com/vr.php?view=18135
Subject: Ubuntu Builder 2.3.1 Supports elementary OS Luna
On November 15, Francesco Muriana has the pleasure of announcing the immediate availability for download of the Ubuntu Builder 2.3.1 open source application.
http://news.softpedia.com/news/Ubuntu-Builder-2-3-1-Supports-elementary-OS-Luna-307441.shtml
Subject: Steam for Linux gets three new games
Steam is a great source for any gamer. It is a place that will allow you to try out and enjoy many of the more popular video games that are available on the market today. Steam Greenlight will allow you to vote on games that you would like to see become available. It is a great system for gamers; they do not have to drop $50 to purchase every game off the shelf. They can simply join Steam and enjoy the most popular ones at a reduced price.
http://opensource.com/life/12/11/steam-linux-gets-three-new-games
Subject: How to setup an IM / VOIP server using Openfire on Ubuntu 12.04
If you looking for an alternative to public IM and VOIP services like Skype and want to create a private secure IM / VOIP network, this guide is for you.
http://www.thefanclub.co.za/how-to/how-setup-im-voip-server-using-openfire-ubuntu-1204
Subject: Could open source software save New York Citys bike share program?
A bike share program that was supposed to be launched last summer in New York City has come to a halt due to software related issues. I can't help but think that if the software was open source, these problems would have been easily resolved, elimating worrisome delays.
http://opensource.com/life/12/11/could-open-source-software-save-new-york-citys-bike-share-program
Subject: Would you like Netflix on Linux?
It's on the way. Developers are working on packages based on a Windows version of Firefox through Wine.
http://www.iheartubuntu.com/2012/11/netflix-on-ubuntu-is-here.html
Subject: Resara Me This
More than any other program, Samba allows Linux desktops to exist in the world of Windows. In fact, Samba historically has allowed Linux to live secretly in the server room as well. It's possible to emulate a Primary Domain Controller from your Linux server, and Windows machines can't tell the difference. The problem is that Microsoft no longer uses PDCs and has turned to Active Directory.
http://www.linuxjournal.com/content/resara-me
Subject: OpenStreetMap launches "Operation Cowboy"
The OpenStreetMap community has announced that it will host its second global "mapathon" during the weekend of 23–25 November; this time, the event is code-named "Operation Cowboy" and will focus on the US. Concentrating on "armchair mapping", aerial images will be surveyed at local meetings, as well as from home. Based on these surveys, the project will then complement its map material for the US. The campaign has its own official Twitter account and hash tag: #OPC2012.
http://www.h-online.com/open/news/item/OpenStreetMap-launches-Operation-Cowboy-1751382.html/from/rss
Subject: Connect the dots: Valve's Big Picture could be a Linux game console
The Xbox 360, PlayStation 3, and Nintendo Wii are nearing their end. As powerful as they have been in the living room, gamers want more. They want better graphics, new user experiences, and more mobility, as much as those things can be at odds with one another. A new wave of game consoles is rising to meet some of those challenges, but perhaps not all: the Nintendo Wii U doesn't seem to be that much more powerful than an Xbox 360, and the next Xbox and PlayStation are rumored to use what amounts to mid-range PC hardware in order to save costs.
http://www.theverge.com/2012/11/16/3652756/valve-big-picture-mode-steam-os-linux-game-console
Subject: 5 Links for Developers and IT Pros 11-14-12
This week, 10 steps to secure cloud services, why the little things matter when it comes to developing apps and tablets are kicking laptops to curb.
http://blog.ness.com/spl/bid/84467/5-Links-for-Developers-and-IT-Pros-11-16-12
Subject: FOSDEM13 Excellent Opportunity for KDE
FOSDEM is one of the largest gatherings of Free Software contributors in the world and happens each February in Brussels (This year on the 2nd & 3rd of February). It's one of the few community-centered conferences in Europe, and the largest volunteer-run Free Software event in Europe as well. Proposals are now invited for talks on KDE, KDE software and general desktop topics. KDE will be in the Cross Desktop Developer Room (devroom), along with Enlightenment, Gnome, Razor, Unity and XFCE. This is a unique opportunity to share KDE with a wide audience of developers.
http://dot.kde.org/2012/11/16/fosdem13-excellent-opportunity-kde
Subject: 3 Open Source School Management Software for Teachers and Students
Many educators might have been hesitant in the past regarding embracing open source software. But not any more as the number that has taken to open source software (OSS) has increased significantly over the years. As more teachers as well as institutions are now engaging with organizations such as Open Source Schools, SchoolForge among others. Consequently, these educators have begun to realize the potential inherent in OSS that can help transform education in many ways.
http://linuxaria.com/article/open-source-school-management-software-for-teachers-and-students?lang=en
Subject: Development of PHP 5.5 begins
The release of a first alpha of PHP 5.5 marks the official beginning of the 5.5.0 release cycle for the scripting language's next major version. PHP 5.5 also marks the end of support for Windows XP and Windows 2003.
http://www.h-online.com/open/news/item/Development-of-PHP-5-5-begins-1751313.html/from/rss
Subject: Harvard Research Scientist: Sharing Discoveries More Efficient, More Honorable Than Patenting Them
Two years ago, after Jay Bradner made a remarkable breakthrough—the discovery of a molecule that, in mice, appeared to trick certain cancer cells into becoming normal cells—he did something unusual. Instead of huddling with lawyers to file for a patent on the molecule, Bradner simply gave his work away. Hoping to get the discovery into the hands of any scientist who could advance it, he published the structure of the compound (called JQ1) and mailed samples to labs around the world. The move, he says, felt like "the more efficient way to do science—and maybe the more honorable way."
http://www.techdirt.com/articles/20121114/07172121043/harvard-research-scientist-sharing-discoveries-more-efficient-more-honorable-than-patenting-them.shtml
Subject: More in the series of bizarre UEFI bugs
A (well, now former) coworker let me know about a problem he was having with a Lenovo Thinkcentre M92p. It booted Fedora UEFI install media fine, but after an apparently successful installation refused to boot. UEFI installs on Windows worked perfectly. Secure Boot was quickly ruled out, but this could still have been a number of things. The most interesting observation was that the Fedora boot option didn't appear in the firmware boot menu at all, but Windows did.
http://mjg59.dreamwidth.org/20187.html


This tender perennial climber is evergreen in Zones 10 and warmer. Cheerful, 1.5-inch flowers in shades of orange and yellow cover this fast-growing vine. The blossoms have a simple form: 5 petals surrounding a brownish purple center. Where grown as an annual, plants can reach 8 feet; when grown as a perennial, 20 feet.
Noteworthy CharacteristicsAnnuals, perennials, and shrubs of this genus are native to warm or tropical regions of Africa, Madagascar, and Asia. Their showy, five-lobed flowers have slender tubes that open to form flat or undulating trumpets. In warmer climates, grow perennial climbers along permanent structures and shrubs in mixed borders. Some cultivars with whitish flowers are available.
CareProvide moist, well-drained soil in full sun with some afternoon shade. In cooler zones, grow in a warm or temperate greenhouse or treat as annuals.
PropagationSow seed over 60°F, or start indoors 6-8 weeks before last frost date with heat.
ProblemsWhiteflies, scale, spider mites on indoor plants.


One of Australia's foremost media agencies is looking for a Social Media Coordinator to join their digital arm. Constantly pushing the boundaries across TV, print, outdoor and direct media they are pioneers in return on investment in new media as well. With strong growth in the social media and digital sector they are looking to expand their team.
You will be responsible for supporting the day-to-day running of brand editorial implementation such as social media content and community activations across a large range of clients. With A-grade attention to detail and an insatiable drive to develop and deliver the best in class solutions, you will be a creative and energetic optimist that is keen on providing a key support role.


text:
The 2017 Doncaster Metropolitan Borough Council election took place on 4 May 2017 as part of the 2017 local elections in the United Kingdom. The election of the Mayor of Doncaster also took place on the same day. All 55 councillors were elected from 21 wards which returned either two or three councillors each by first-past-the-post voting for a four-year term of office.

The election resulted in the Labour Party retaining control of the Council, with an increased majority after gaining two seats from UKIP.

Result

Council Composition

Council composition
Following the last election in 2015, the composition of the council was:

After the election, the composition of the council was:

MF - Mexborough First
I - Independent
U - UKIP

Mayoral election

Ward results

Adwick-Le-Street and Carcroft

Armthorpe

Balby South

Bentley

Bessacarr

Conisbrough

Edenthorpe & Kirk Sandall

Edlington & Warmsworth

Finningley

Hatfield

Hexthorpe & Balby North

Mexborough

Norton & Askern

Roman Ridge

Rossington & Bawtry

Sprotbrough

Stainforth & Barnby Dun

Thorne & Moorends

Tickhill & Wadworth

Town

Wheatley Hills & Intake

References

2017
2017 English local elections
2010s in South Yorkshire

redpajama_set_name: RedPajamaWikipedia


text:
Lázaro Vinícius Marques dit Lázaro, né le  à Belo Horizonte au Brésil, est un footballeur brésilien qui évolue au poste de milieu offensif à l'UD Almería.

Biographie

Flamengo
Formé au CR Flamengo, Lazaro est considéré comme l'un des joueurs les plus prometteurs de sa génération.

Son parcours dans le  est néanmoins marqué par l'accident tragique de l' où plusieurs de ses jeunes camarades perdent la vie le . Lazaro échappe lui à l'accident, ayant profité de son jours de congé pour retrouver sa famille.

Le , alors qu'il n'a pas encore fait ses débuts en professionnel, le club lui propose un contrat courant jusqu'en 2025 avec une clause libératoire à 80 millions d'euros qui prendra effet le , jour de ses 18 ans. Il joue son premier match en professionnel le 27 septembre 2020, lors d'une rencontre de championnat face à Palmeiras. Il entre en jeu à la place de Lincoln et les deux équipes se neutralisent (1-1).

UD Almería
Le , Lázaro rejoint l'Espagne afin de s'engager en faveur de l'UD Almería. Il signe un contrat courant jusqu'en juin 2028.

Lázaro joue son premier match sous ses nouvelles couleurs le , lors d'une rencontre de championnat face au CA Osasuna. Il entre en jeu à la place de Lucas Robertone et son équipe s'incline (0-1 score final).

En équipe nationale
Lazaro compte deux sélections avec l'équipe du Brésil des moins de 16 ans, toutes les deux obtenues en 2017.

Lazaro est sélectionné avec l'équipe du Brésil des moins de 17 ans pour participer à la Coupe du monde des moins de 17 ans qui a lieu au Brésil. Il a un rôle de remplaçant durant ce tournoi, ne jouant que trois matchs. Cependant cela suffit pour qu'il se distingue malgré ce faible temps de jeu, en donnant la victoire au Brésil, en demi-finale contre la France. Alors que les français menaient au score, ils sont rejoints et dans les derniers instants de la partie Lazaro marque le but de la victoire après être entré en jeu (2-3 score final). Il réalise le même exploit en finale, alors que le Brésil affronte le Mexique. Lazaro entre en jeu et alors que le score est de un partout il inscrit son deuxième but dans la compétition, celui de la victoire finale pour les Brésiliens (1-2).

Style de jeu
La position préférentielle de Lazaro est un milieu offensif axial, il est décrit comme un joueur créatif, efficace dans les un contre un et doué pour déséquilibrer les défenses adverses.

Palmarès
 CR Flamengo
 Championnat du Brésil
 Champion : 2020.
 Équipe du Brésil des moins de 17 ans
 Coupe du monde des moins de 17 ans
 Vainqueur : 2019.

Statistiques

Notes et références

Liens externes

Footballeur brésilien
Joueur du Clube de Regatas do Flamengo
Joueur de l'UD Almería
Naissance en mars 2002
Naissance à Belo Horizonte
Mononyme


text:
Q: Maxima: eliminate variables from equations Given N equations in K variables,
can Maxima produce N-J equations in K-J variables?
SOLVE and ELIMINATE seem unable, about to reach for pen and paper.

A: (%i1) elim ([a = x + y, b = y + z, c = z + x, a = b * c], [a, b, c]);
(%o1)     elim([a = y + x, b = z + y, c = z + x, a = b c], [a, b, c])
(%i2) load (to_poly);
(%o2)  ~/maxima-5.44.0/share/to_poly_solve/to_poly.lisp
(%i3) elim ([a = x + y, b = y + z, c = z + x, a = b * c], [a, b, c]);
         2
(%o3) [[z  + (y + x) z + (x - 1) y - x],
                                     [b z - y + b x - x, z + x - c, y + x - a]]
(%i4) solve (first (%o3), x);
                                     2
                                    z  + y z - y
(%o4)                        [x = - ------------]
                                     z + y - 1

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