Influence de la variabilité du milieu sur la richesse taxonomique, l'exemple du rapport Rb/Sr dissous et des macro-invertébrés benthiques

Ce travail est une contribution au débat biodiversité/stabilité. L'utilisation de paramètres pris comme indicateurs de la diversité biologique et de la stabilité du chimisme de l'eau : le nombre de taxons de macro-invertébrés benthiques (selon IBGN) et la variabilité (écart-type exprimé en pourcents) du rapport rubidium/strontium dissous, nous a permis de montrer une corrélation négative significative entre les deux indices. Cette relation, établie sur 36 stations de 22 cours d'eaux du genevois, est interprétée comme mettant en évidence un effet négatif de la variabilité temporelle de la qualité de l'eau sur le nombre d'espèces de macro-invertébrés. Bien que reposant sur des aspects réducteurs de la biodiversité et de la stabilité des écosystèmes, elle est un exemple de lien inverse entre l'instabilité et la diversité biologique. Elle tend, en outre, à souligner l'efficacité d'une utilisation dynamique des données physicochimiques par rapport à l'interprétation de valeurs absolues.The aim of this work is to make a contribution to the biodiversity/stability debate. The use of given parameters as indicators of biologic diversity and stability of the chemical composition of water, more specifically, the average number of macroinvertebrate taxons (according to the IGBN) and the variability (standard deviation expressed as a percentage) of the Rb/Sr dissolved ratio, allowed the determination of a significant negative correlation between these two indices. This relationship, based upon the results obtained from 36 sampling sites located on 22 rivers in the canton of Geneva (Switzerland), is interpreted as evidence of the negative impact of temporal variations in water quality on the number of macroinvertebrates species. Though relying upon reductive aspects of biodiversity and stability of ecosystems, it represents an example of the inverse relationship between instability and biologic diversity. Moreover, it tends to emphasize the advantage of using dynamic variations of chemical parameters rather than their absolute values in order to appreciate the loops and relationships occurring in natural ecosystems

Modern American populism: Analyzing the economics behind the Silent Majority, the Tea Party and Trumpism

This article researches populism, more specifically, Modern American Populism (MAP), constructed of white, rural, and economically oppressed reactionarianism, which was borne out of the political upheaval of the 1960’s Civil Rights movement. The research looks to explain the causes of populism and what leads voters to support populist movements and politicians. The research focuses on economic anxiety as the main cause but also examines an alternative theory of racial resentment. In an effort to answer the question, what causes populist movements and motivations, I apply a research approach that utilizes qualitative and quantitative methods. There is an examination of literature that defines populism, its causes and a detailed discussion of the case studies, including the 1972 election of Richard Nixon; the Tea Party election of 2010; and the 2016 election of Donald Trump. In addition, statistical data analysis was run using American National Election Studies (ANES) surveys associated with each specific case study. These case studies were chosen because they most represent forms of populist movements in modern American history. While ample qualitative evidence suggested support for the hypothesis that economic anxiety is a necessary condition for populist voting patterns that elected Nixon, the Tea Party and Trump, the statistical data only supported the hypothesis in two cases, 2010 and 2016, with 1972 coming back inconclusive. The data also suggested that both economic anxiety and racial resentment played a role in 2010 and 2016, while having no significant effect in 1972 in either case. This suggests that further research needs to be conducted into additional populist case studies, as well as an examination into the role economic anxiety and economic crises play on racial resentment and racially motivated voting behavior

Evolution physico-chimique des eaux du Léman

National audienc

Evolution physico-chimique des eaux du Léman. Campagne 2000

National audienc