Do riverine barriers, history or introgression shape the genetic structuring of a common shrew (Sorex araneus) population?

The common shrew (Sorex araneus) is subdivided into numerous chromosome races. The Valais and Cordon chromosome races meet and hybridize at a mountain river in Les Houches (French Alps). Significant genetic structuring was recently reported among populations found on the Valais side of this hybrid zone. In this paper, a phylogenetic analysis and partial Mantel tests are used to investigate the patterns and causes of this structuring. A total of 185 shrews were trapped at 12 localities. All individuals were typed for nine microsatellite loci. Although several mountain rivers are found in the study area, riverine barriers do not have a significant influence on gene flow. Partial Mantel tests show that our result is caused by the influence of the hybrid zone with the Cordon race. The geographical patterns of this structuring are discussed in the context of the contact zone, which appears to extend up to a group of two rivers. The glacier they originate from is known to have cut the Arve valley as recently as 1818. The recent history of this glacier, its moraine and possibly rivers, may therefore be linked to the history of this hybrid zone

Rapport d'évaluation du programme Nature en ville de la Ville de Neuchâtel

La Direction de l'urbanisme, de l'économie et de l'environnement de la Ville de Neuchâtel a mandaté l'Unité de politiques locales et d'évaluation de l'IDHEAP et le bureau d'études en écologie appliquée L'Azuré pour évaluer le programme Nature en ville de la Ville de Neuchâtel. Le but de l'évaluation est de déterminer si les objectifs visés par le programme ont été atteints et d'améliorer l'ancrage du programme Nature en ville dans le fonctionnement de l'administration communale

Estimation of kinetic parameters in a chromatographic separation model via Bayesian inference

A modelagem de processos de adsorção tem sido empregada com frequência nas indústrias químicas, petroquímicas e refinarias, por exemplo para separação e purificação de misturas em unidade de Leito Móvel Simulado (LMS). Na representação matemática do modelo, a determinação de parâmetros é um passo importante para o projeto de condições cromatográficas para a separação contínua, em processos do tipo LMS. Este trabalho tem por objetivo a análise de estimativa de parâmetros em processos de adsorção, usando um sistema cromatográfico com uma coluna, para a separação das substâncias Glicose e Frutose. Investiga-se o uso da abordagem Bayesiana, através de métodos de Monte Carlo via Cadeias de Markov (MCMC), assim como o uso da abordagem da máxima verossimilhança, utilizando duas técnicas estocásticas diferentes, o Algoritmo de Colisão de Partículas (PCA - Particle Collision Algorithm), e o Algoritmo de Otimização por Enxame de Partículas (PSO - Particle Swarm Optimization) para executar a tarefa de minimização da função objetivo. Diferentes casos são apresentados com o objetivo de analisar a significância estatística das estimativas obtidas para os parâmetros, fazendo-se uma comparação crítica entre a solução via inferência Bayesiana e via minimização da função objetivo com métodos estocásticos. Os resultados obtidos demonstram que o uso da abordagem Bayesiana fornece uma proposta vantajosa para a estimativa de parâmetros em transferência de massa, oferecendo resultados com maior riqueza de informação estatística.The modeling of adsorption processes appears quite frequently in the chemical industry, petrochemical plants and refineries, for example for separation and purification of mixtures in Simulated Moving Bed (SMB) units. In the mathematical formulation, the accurate determination of the model parameters is an important step for the design of chromatographic conditions for continuous separation in SMB processes. This work is aimed at the estimation of the model parameters in adsorption processes, using a chromatographic column for the separation of glucose and fructose. The Bayesian framework for inverse problems is investigated through the implementation of Markov Chain Monte Carlo methods (MCMC) and a critical comparison against the classical Maximum Likelihood approach, with the minimization of the objective function via two different stochastic techniques, namely the Particle Collision Algorithm (PCA), and the Particle Swarm Optimization (PSO) is performed. Different cases are presented in order to investigate the statistical significance of the estimates obtained, and perform comparisons between the solution via Bayesian inference and via the minimization of the objective function with the stochastic methods. The results demonstrate that the Bayesian approach employs less computational effort to achieve estimates with comparable statistical information.Peer Reviewe

Anatomy of terminal moraine segments and implied lake stability on Ngozumpa Glacier, Nepal, from electrical resistivity tomography (ERT)

This research was supported financially by the European Commission FP7-MC-IEF (PIEF-GA-2012-330805), the University Centre in Svalbard (UNIS), National Geographic Society GRANT #W135-10.Moraine-dammed lakes at debris-covered glaciers are becoming increasingly common and pose significant outburst flood hazards if the dam is breached. While moraine subsurface structure and internal processes are likely to influence dam stability, only few sites have so far been investigated. We conducted electrical resistivity tomography (ERT) surveys at two sites on the terminal moraine complex of the Ngozumpa Glacier, Nepal, to aid assessment of future terminus stability. The resistivity signature of glacier ice at the site (100-15 kΩ m) is more consistent with values measured from cold glacier ice and while this may be feasible, uncertainties in the data inversion introduce ambiguity to this thermal interpretation. However, the ERT data does provide a significant improvement to our knowledge of the subsurface characteristics at these sites, clearly showing the presence (or absence) of glacier ice. Our interpretation is that of a highly complex latero-terminal moraine, resulting from interaction between previous glacier advance, recession and outburst flooding. If the base-level Spillway Lake continues to expand to a fully formed moraine-dammed glacial lake, the degradation of the ice core could have implications for glacial lake outburst risk.Publisher PDFPeer reviewe

Spatially Explicit Analysis of Metal Transfer to Biota: Influence of Soil Contamination and Landscape

Concepts and developments for a new field in ecotoxicology, referred to as “landscape ecotoxicology,” were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn) in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi) and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula). Total and CaCl2-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl2-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging) were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc.) are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our understanding of pollutant transfer and effects in ecosystems

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe