An approach to identify and levels of nesting habitat selection: a cross-scale analysis of Goshawk preferences

Nest site selection may result from diverse agents that work on different spatial scales, and amultilevel analysis can offer a more realistic vision of the search image (proximate factors) and of the scale of nesting habitat selection by a species. Cross-scale analyses of nesting habitat preferences are scarce : in this respect, the Goshawk (Accipiter gentilis) is one of the most intensely investigated species, but most studies have focused only on a single habitat feature. This study, conducted in Burgundy (Eastern France), describes Goshawk nest site preferences by using a multilevel spatial scale analysis (nest tree level, stand level, landscape level), and identifies the habitat level that represents the supposed proximate factor for this species. We identified 57 active Goshawk nest sites (6 .7 active nests/ 100 km2) . The stepwise logistic regression showed that 4 variables of the nest stand structure (high tree dbhs, high crown volumes, high flight space and short distance to trails) and 2 variables of the landscape surrounding nest trees (low avian prey richness for both 100-500 and 501-2000 g classes) were significant predictors of Goshawk nest site selection (98% ofnests correctly reclassified). We hypothesised that Goshawk species choose nest sites on the basis of the overall structural features of the stand, and then focus on a particular nest tree

Fluorescence spectroscopy as a specific tool for the interaction study of two surfactants with natural and synthetic organic compounds

International audienceFour different techniques were used to study the binding of cationic cetyltrimethylammonium bromide (CTAB) and non-ionic nonylphenylethoxyl (NPE) surfactants to three synthetic organic components that mimic humic-like aggregates and to two natural aggregated humic substances (HS) extracted from aquatic suspended matter. The composition of synthetic organic components were chosen to be similar to high molecular weight highly processed terrigenous HS and low and high molecular weight less processed terrigenous (or aquatic terrigenous) HS. The natural HS were extracted under two different meteorological conditions (rainy and dry periods). No significant interaction between the non-ionic surfactant and any of the studied compounds was found. Concerning CTAB; pH, conductivity and turbidity measurements, along with fluorescence spectroscopy were combined to provide a better understanding of interactions between organic aggregates and the surfactant. The spectroscopic data show that a "highly processed terrigenous HS" fluorophore interacts in a different way with the cationic surfactant than an "aquatic terrigenous (or less processed terrigenous) HS" fluorophore does. Under similar conditions, some spectral changes in the fluorescence signal are correlated to changes in non-specific physical-chemical parameters (pH, turbidity, conductivity) for the organic compounds tested. The complexation mechanism is essentially governed by charge neutralization, which can be monitored specifically by the fluorescence of the organic moieties

Forces et paradoxes de la planification française du tourisme

International audienceAvec de vastes surfaces et une grande diversité géographique et culturelle, la France est devenue un acteur du tourisme essentiel en Europe. Le présent chapitre présente les principales caractéristiques du tourisme en France, pour ensuite aborder les différentes politiques touristiques, et ce à différentes échelles territoriales. En particulier, dans ce contexte, est discuté le devenir du tourisme national

A Physiological Approach to Recurrent Nephrolithiasis and its Genetic Determinants

We report a case of a 63-year-old patient with recurrent nephrolithiasis for over 40 years and a significant family history of nephrolithiasis. The patient underwent full investigation at our department. He presented hypercalcemia, hypophosphatemia and hypercalciuria, with parathyroid hormone level in the normal range. A calcium load test and a fluorocholine PET-CT excluded primary hyperparathyroidism. Abnormal secretion of parathyroid hormone-related protein and sarcoidosis were also excluded. Genetic analysis showed mutations encoding for 25(OH)-vitamin D3-24-hydroxylase (CYP24A1) and Na-dependent phosphate cotransporter 2c (SLC34A3). This case affords insights into the biological pathways that underlie the role of genetic inheritance and accrued risk of development of nephrolithiasis.info:eu-repo/semantics/publishedVersio

Interaction of pyrene fluoroprobe with natural and synthetic humic substances: Examining the local molecular organization from photophysical and interfacial processes

International audienceThe direct and indirect interaction mechanisms of pyrene with (i) various molecular weight fractions of a synthetic humic-like substance (SyHA) and (ii) extracts of natural humic acids (NHA) from Moselle River suspended matter, were investigated using quenching fluorescence and surface tension measurements. Humic materials were characterized in a previous study. The Stern-Volmer associative constants were determined from the quenching technique. Surface tension measurements revealed an increase in surface activity as a function of concentration for each humic fraction independently of the pyrene presence in solution, even during the formation of humic micelles. The results obtained suggest the possibility of specific intermolecular interactions occurring during pyrene entrapment within humic acids. In addition, we show that molecular weight, aliphatic chains (especially those containing nitrogen groups) and acidity are determinant characteristics for pollutant entrapment capacity at concentrations below the critical micellar concentration (CMC) of humic substances