Evaluating the influence of spatial uncertainty in locality points for species distributional modeling

1. Species distribution modelling is used increasingly in both applied and theoretical research to predict how species are distributed and to understand attributes of species' environmental requirements. In species distribution modelling, various statistical methods are used that combine species occurrence data with environmental spatial data layers to predict the suitability of any site for that species. While the number of data sharing initiatives involving species' occurrences in the scientific community has increased dramatically over the past few years, various data quality and methodological concerns related to using these data for species distribution modelling have not been addressed adequately. 2. We evaluated how uncertainty in georeferences and associated locational error in occurrences influence species distribution modelling using two treatments: (1) a control treatment where models were calibrated with original, accurate data and (2) an error treatment where data were first degraded spatially to simulate locational error. To incorporate error into the coordinates, we moved each coordinate with a random number drawn from the normal distribution with a mean of zero and a standard deviation of 5 km. We evaluated the influence of error on the performance of 10 commonly used distributional modelling techniques applied to 40 species in four distinct geographical regions. 3. Locational error in occurrences reduced model performance in three of these regions; relatively accurate predictions of species distributions were possible for most species, even with degraded occurrences. Two species distribution modelling techniques, boosted regression trees and maximum entropy, were the best performing models in the face of locational errors. The results obtained with boosted regression trees were only slightly degraded by errors in location, and the results obtained with the maximum entropy approach were not affected by such errors. 4. Synthesis and applications. To use the vast array of occurrence data that exists currently for research and management relating to the geographical ranges of species, modellers need to know the influence of locational error on model quality and whether some modelling techniques are particularly robust to error. We show that certain modelling techniques are particularly robust to a moderate level of locational error and that useful predictions of species distributions can be made even when occurrence data include some error.

The Perception of the Elements in the Hindu Traditions

The essays in this volume, contributions to an international symposium at the University of Lausanne in June 1998, represent the perception of the elements as a framework for the history of religions (Maya Burger), exemplified by the Hindu traditions. Each element is treated by a specialist in a different academic field in order to bring out a variety of approaches important to the discipline of the history of religion. Ether (akasa) was assigned to philosophy (Wilhelm Halbfass), wind to the history of religion (Bettina Bäumer), fire to classical philology (Peter Schreiner), water to a specialist on Indian medicine (Arion Rosu) and earth to anthropology (Gabriella Eichinger Ferro-Luzzi, specializing on Tamil literature). Les articles du présent volume, issus d'un symposium international ayant eu lieu à l'Université de Lausanne en juin 1998, présentent la perception des éléments comme base de recherche de l'étude des religions (Maya Burger), exemplifiée à l'aide des traditions hindoues. Chaque élément est traité par un spécialiste d'une discipline académique particulière dans le but de souligner la variété des approches nécessaire à la discipline d'histoire des religions. L'éther (akasa) a été considéré sous l'angle de la philosophie (Wilhelm Halbfass), le vent sous celui de l'histoire des religions (Bettina Bäumer), le feu sous celui de la philologie classique (Peter Schreiner), l'eau par un spécialiste de la médecine indienne (Arion Rosu) et la terre sous l'angle de l'anthropologie (Gabriella Eichinger Ferro-Luzzi, se concentrant sur la littérature tamoule).

The multipoint Morisita index for the analysis of spatial patterns

In many fields, the spatial clustering of sampled data points has many consequences. Therefore, several indices have been proposed to assess the level of clustering affecting datasets (e.g. the Morisita index, Ripley's Kfunction and Rényi's generalized entropy). The classical Morisita index measures how many times it is more likely to select two measurement points from the same quadrats (the data set is covered by a regular grid of changing size) than it would be in the case of a random distribution generated from a Poisson process. The multipoint version (k-Morisita) takes into account k points with k >= 2. The present research deals with a new development of the k-Morisita index for (1) monitoring network characterization and for (2) detection of patterns in monitored phenomena. From a theoretical perspective, a connection between the k-Morisita index and multifractality has also been found and highlighted on a mathematical multifractal set.

Spatial predictions of phylogenetic diversity in conservation decision making.

Considering genetic relatedness among species has long been argued as an important step toward measuring biological diversity more accurately, rather than relying solely on species richness. Some researchers have correlated measures of phylogenetic diversity and species richness across a series of sites and suggest that values of phylogenetic diversity do not differ enough from those of species richness to justify their inclusion in conservation planning. We compared predictions of species richness and 10 measures of phylogenetic diversity by creating distribution models for 168 individual species of a species-rich plant family, the Cape Proteaceae. When we used average amounts of land set aside for conservation to compare areas selected on the basis of species richness with areas selected on the basis of phylogenetic diversity, correlations between species richness and different measures of phylogenetic diversity varied considerably. Correlations between species richness and measures that were based on the length of phylogenetic tree branches and tree shape were weaker than those that were based on tree shape alone. Elevation explained up to 31% of the segregation of species rich versus phylogenetically rich areas. Given these results, the increased availability of molecular data, and the known ecological effect of phylogenetically rich communities, consideration of phylogenetic diversity in conservation decision making may be feasible and informative.

A homing procedure for studying spatial memory in immature and adult rodents

In this procedure, subjects learn the spatial position of one hole out of many, that allows them to escape from a large open-field into their home cage. The arena is circular and can be rotated between trials so that no proximal landmark is permanently associated with the target hole. This task is thus similar to the Morris water maze procedure, since subjects must remember the position of the escape hole relative to extra-arena cues only. In addition it allows studying the importance of olfactory cues such as scent marks in or around a hole. Since the motivation is to reach home and the motor requirement is low, this task provides a useful alternative to the Morris place navigation task for studying spatial orientation in weanling or senescent rats. Examples are given showing that various behavioural parameters provide a good estimation as how subjects learn this task.

GWAS of human bitter taste perception identifies new loci and reveals additional complexity of bitter taste genetics.

Human perception of bitterness displays pronounced interindividual variation. This phenotypic variation is mirrored by equally pronounced genetic variation in the family of bitter taste receptor genes. To better understand the effects of common genetic variations on human bitter taste perception, we conducted a genome-wide association study on a discovery panel of 504 subjects and a validation panel of 104 subjects from the general population of São Paulo in Brazil. Correction for general taste-sensitivity allowed us to identify a SNP in the cluster of bitter taste receptors on chr12 (10.88- 11.24 Mb, build 36.1) significantly associated (best SNP: rs2708377, P = 5.31 × 10(-13), r(2) = 8.9%, β = -0.12, s.e. = 0.016) with the perceived bitterness of caffeine. This association overlaps with-but is statistically distinct from-the previously identified SNP rs10772420 influencing the perception of quinine bitterness that falls in the same bitter taste cluster. We replicated this association to quinine perception (P = 4.97 × 10(-37), r(2) = 23.2%, β = 0.25, s.e. = 0.020) and additionally found the effect of this genetic locus to be concentration specific with a strong impact on the perception of low, but no impact on the perception of high concentrations of quinine. Our study, thus, furthers our understanding of the complex genetic architecture of bitter taste perception.

Spatial distribution of economic activities: an empirical approach usingself-organizing maps

The aim of this paper is to analyse the colocation patterns of industries and firms. We study the spatial distribution of firms from different industries at a microgeographic level and from this identify the main reasons for this locational behaviour. The empirical application uses data from Mercantile Registers of Spanish firms (manufacturers and services). Inter-sectorial linkages are shown using self-organizing maps. Key words: clusters, microgeographic data, self-organizing maps, firm location JEL classification: R10, R12, R34

Decentralization, happiness and the perception of institutions

This paper analyses whether the different powers and resources at the disposal of local and regional governments across Europe deliver greater satisfaction with political institutions and lead to greater personal happiness. The analysis uses microdata from the four available waves of the European social survey (2002, 2004, 2006 and 2008), including more than 160,000 observations of individuals living in 29 European countries. Our results reveal that political and fiscal decentralization have a positive and significant effect on individuals’ overall happiness. Fiscal decentralization also exerts a significant effect on the level of satisfaction with political and economic institutions and with the education and health systems, whereas the effect of political decentralization on these variables is more limited. The results show that citizens seem to be happier with the actual capacity of their local governments to deliver than with the general principle that they can have a say on their daily politics and policies. Keywords: Happiness, well-being, satisfaction, fiscal and political decentralization, Europe. JEL codes: H11, H77

Stress Perception in Public Organizations: Expanding the Job Demands - Job Resources Model by Including Public Service Motivation

Although stress has been a longstanding issue in organizations and management studies, it has never been studied in relation to Public Service Motivation. This article therefore aims to integrate PSM into the job demands-job resources model of stress in order to determine whether PSM might contribute to stress in public organizations. Drawing upon original data from a questionnaire in a Swiss municipality, this study unsurprisingly shows that "red tape" is an antecedent of stress perception, whereas satisfaction with organizational support, positive feedback, and recognition significantly decrease the level of perceived stress. Astonishingly, the empirical results show that PSM is positively and significantly related to stress perception. By increasing individuals' expectations towards their jobs, PSM might thus contribute to increased pressure on public agents. Ultimately, this article investigates the "dark side" of PSM, which has been neglected by the literature thus far.

Microgeographical patterns of schistosomiasis and water contact behavior; examples from Africa and Brazil

This paper examines the results of spatial (microgeographical) water contact/schistosomiasis studies in two African (Egyptian and Kenyan) and one Brazilian communities. All three studies used traditional cartographic and statistical methods but one of them emploeyd also GIS (geographical information systems) tools. The advantage of GIS and their potential role in schistosomiasis control are briefly described. The three cases revealed considerable variation in the spatial distribution of water contact, transmission parameters and infection levels at the household and individual levels. All studies showed considerable variation in the prevalence and intensity of infection between households. They also show a variable influence of distance on water contact behavior associated with type of activity, age, sex, socioeconomic level, perception of water quality, season and availability of water in the home. Water contact behavior and schistosomiasis were evaluated in the Brazilian village of Nova União within the context of water sharing between household and age/sex groups. Recommendations are made for further spatial studies on the transmission and control of schistosomiasis.

Prendre des risques, ça rapporte ? Conduites à risques et perception des risques chez des adolescents tout-venant

Risk taking and its association with substance use by adolescents are often studied among clinical populations. The behavior of non-clinical adolescent samples is less well-known. According to some scholars, the adoption of risk behaviors can be predicted by a function of perceptions of both benefits and risks of such behaviors. However, the literature is still controversial about their respective significance. In this study, a non-clinical sample of 221 adolescents, aged 14 to 20, completed two questionnaires: the RIPS-R to estimate risk taking behaviors as well as perception of the risks and benefits of such behaviors, and the DEP-ADO to measure substance use. Our results show a high annual prevalence of socially accepted risk behaviors (drinking alcohol, not studying for exams, smoking tobacco). However, socially repressed behaviors (brawling, vandalism) are very occasional and are associated with problematic substance use. Globally, engagement in risk behaviors is more closely linked with the perceptions of its benefits than the perception of its risks. Finally, limitations and implications of these results for research and prevention are provided. Les prises de risques et leur association avec la consommation de substances chez les adolescents ont souvent été étudiées auprès de populations cliniques. Le comportement des jeunes tout-venant est en revanche moins bien connu. Selon certains théoriciens, la participation à des conduites à risques peut être déterminée en fonction des perceptions de leurs bénéfices et dangers potentiels. Toutefois, la littérature ne s'accorde pas sur l'importance respective que ces perceptions revêtent. Dans cette étude, 221 adolescents tout-venant, âgés de 14 à 20 ans, ont complété deux questionnaires : le RIPS-R pour évaluer la prise de risques et leur perception en termes de risques et de bénéfices, et la DEP-ADO pour mesurer la consommation de substances. Les résultats mettent en évidence une prévalence annuelle élevée des comportements à risques socialement acceptables (boire de l'alcool, fumer du tabac). En revanche, les comportements réprimés socialement (bagarres, actes de vandalisme) s'avèrent très occasionnels et sont associés à la consommation problématique de substances. Globalement, c'est la perception des bénéfices qui est le plus fortement liée au fait d'adopter un comportement à risque. Finalement, les limites et les implications pratiques de ces résultats sont discutées. © 2010 Elsevier Masson SAS. Tous droits réservés.