Darker eumelanic barn owls better withstand food depletion through resistance to food deprivation and lower appetite

The intensity of selection exerted on ornaments typically varies between environments. Reaction norms may help to identify the conditions under which ornamented individuals have a selective advantage over drab conspecifics. It has been recently hypothesized that in vertebrates eumelanin-based coloration reflects the ability to regulate the balance between energy intake and expenditure. We tested two predictions of this hypothesis in barn owl nestlings, namely that darker eumelanic individuals have a lower appetite and lose less weight when food-deprived. We found that individuals fed ad libitum during 24h consumed less food when their plumage was marked with larger black spots. When food-deprived for 24h nestlings displaying larger black spots lost less weight. Thus, in the barn owl the degree of eumelanin-based coloration reflects the ability to withstand periods of food depletion through lower appetite and resistance to food restriction. Eumelanic coloration may therefore be associated with adaptations to environments where the risk of food depletion is hig

Catastrophic chromosomal restructuring during genome elimination in plants.

Genome instability is associated with mitotic errors and cancer. This phenomenon can lead to deleterious rearrangements, but also genetic novelty, and many questions regarding its genesis, fate and evolutionary role remain unanswered. Here, we describe extreme chromosomal restructuring during genome elimination, a process resulting from hybridization of Arabidopsis plants expressing different centromere histones H3. Shattered chromosomes are formed from the genome of the haploid inducer, consistent with genomic catastrophes affecting a single, laggard chromosome compartmentalized within a micronucleus. Analysis of breakpoint junctions implicates breaks followed by repair through non-homologous end joining (NHEJ) or stalled fork repair. Furthermore, mutation of required NHEJ factor DNA Ligase 4 results in enhanced haploid recovery. Lastly, heritability and stability of a rearranged chromosome suggest a potential for enduring genomic novelty. These findings provide a tractable, natural system towards investigating the causes and mechanisms of complex genomic rearrangements similar to those associated with several human disorders

Charcoal analysis and wood diameter: inductive and deductive methodological approaches for the study of firewood collecting practices

International audienc

The use of the Infection and Treatment Method vaccine in controlling East Coast Fever in Kenya: Does gender matter for adoption and impact?

United States Agency for International DevelopmentInternal Revie

Une Approche filière pour limiter les risques d'infection par Salmonella des consommateurs des produits de volaille à la Réunion

A la Réunion, la production de volailles est en constante augmentation malgré la menace perpétuelle de nombreuses pathologies et notamment le spectre du virus H5N1. La viande de poulet représente les apports majeurs en protéines animales des consommateurs réunionnais. Ces derniers, caractérisés par une multiplicité culturelle et religieuse, sont notamment très friands de charcuterie 100% volaille comme certaines saucisses ou pâtés à consommer quasiment crus. Or, les poulets de chair sont souvent infectés par Salmonella spp.,une des deux bactéries les plus incriminées dans les toxi-infections alimentaires dans le monde. Outre le problème de santé publique, la présence de cette bactérie constitue aussi un péril économique pour la filière avicole. L'objectif général de notre étude est donc d'identifier les mesures spécifiques pour limiter la contamination des produits avicoles par Salmonella spp. offerts aux consommateurs réunionnais. Nos objectifs spécifiques sont d'évaluer (1) d'évaluer le niveau d'infection des volailles et de contamination des produits avicoles, (2) de confirmer si la consommation de produits avicoles peut avoir un impact sur la santé du consommateur (3) d'identifier les facteurs de risque majeurs d'infection des volailles ou de contamination des produits pour prendre les mesures correctives. En fin de période d'élevage, plus de 22% des bandes (60 élevages enquêtés) sont infectés par Salmonella spp. avec quatre sérovars majoritaires S. Blockley, S. Typhimurium, S. Virchow et S. Livingstone. En fin d'abattoir, 56% des lots de carcasses (110 lots prélevés) sont contaminés avec S. Blockley S. Typhimurium, S. Virchow et S. Hadar comme sérovars majeurs. L'électrophorèse à champs pulsés nous a permis de comparer les souches de Salmonella spp. isolées chez la volaille ou ses produits, l'environnement et chez l'homme. Les souches humaines proviennent de patients présentant une diarrhée aigue nécessitant un prélèvement ou une hospitalisation. Cette méthode met en évidence une proximité génétique (plus de 80% d'homologie) entre les souches animales et humaines au sein des sérovars majoritaires. Enfin, les facteurs de risque d'infection des volailles ont été déterminés : proximité des champs de cannes (OR=7.92; [1.10;90.05]), statut de la bande précédente vis à vis de Salmonella (OR=6.89; [1.30;36.45]), age des poulaillers (OR=5.36; [1.20;29.52]) et administration d'antibiotiques aux poussins d'un jour sont associés avec un risque élevé d'infection par Salmonella. Néanmoins, l'application rigoureuse des étapes de nettoyage et désinfection peuvent réduire le risqué d'infection (OR=0.05; [0.01;0.79]). Ces résultats permettent de prendre les mesures prioritaires pour lutter plus efficacement contre les contaminations liées aux salmonelles dans la filière volaille à la Réunion. Ils confirment aussi la nécessité de maintenir une surveillance des contaminations bactériennes potentiellement liées aux productions animales et de renforcer celle-ci par rapport aux phénomènes de résistance aux antibiotiques. (Texte intégral

Dead wood gathering among Neanderthal groups: Charcoal evidence from Abric del Pastor and El Salt (Eastern Iberia)

We present here a new approach combining the microscopic characterization of fungal decay features and the fragmentation degree of the charcoal remains from Middle Palaeolithic combustion structures: features H4 and H11 from Abric del Pastor, unit IV (>75 ka BP) and features H50 and H57 from El Salt, unit Xb (ca. 52 ka BP), Eastern Iberia. The observation of wood degradation patterns that occurred prior to charring followed by their quantitative analysis according to previous experimental studies revealed differences between the alteration degrees of the firewood used in the hearths, highlighting the existence of firewood acquisition criteria based on dead wood gathering and also suggesting smoke-related functions. Coupled with fragmentation analyses, this method highlighted possible post-depositional processes affecting the higher degraded charcoals. These results lead us to propose a quantitative analysis of the fungal decay patterns on Middle Palaeolithic charcoal reinforcing the previous hypotheses about dead wood gathering among Neanderthal groups as an accessible and available resource in the surroundings. These data have significant implications for the interpretation of firewood use and management by Palaeolithic hunter-gatherers which was traditionally defined as an opportunistic activity according to the absence of selection criteria based on specific taxa

Perception, cognition, and linguistic structure: The effect of linguistic modularity and cognitive style on sociolinguistic processing

The Interface Principle posits that morphosyntactic variation does not elicit the same kinds of perceptual reactions as phonetic variables because “members of the speech community evaluate the surface form of language but not more abstract structural features” (Labov, 1993:4). This article examines the effect of linguistic modularity on listeners’ social evaluations. Our point of departure is the sociolinguistic monitor, a hypothesized cognitive mechanism that governs frequency-linked perceptual awareness (Labov, Ash, Ravindranath, Weldon, & Nagy, 2011). Results indicate that “higher level” structural variables are available to the sociolinguistic monitor. Moreover, listeners’ reactions are conditioned by independent effects of region of provenance and individual cognitive style. Overall, our findings support the claim that sociolinguistic processing is influenced by a range of social and psychological constraints (Campbell-Kibler, 2011; Preston, 2010; Wagner & Hesson, 2014) while also demonstrating the need for models of sociolinguistic cognition to include patterns of grammatical variation (Meyerhoff & Walker, 2013; Walker, 2010)

Genetic Regulation of Vessel Morphology in Populus.

During secondary growth, forest trees can modify the anatomy of the wood produced by the vascular cambium in response to environmental conditions. Notably, the trees of the model angiosperm genus, Populus, reduce the risk of cavitation and hydraulic failure under water stress by producing water-conducting vessel elements with narrow lumens, which are more numerous and more interconnected with each other. Here, we determined the genetic architecture of vessel traits affecting hydraulic physiology and resilience to water stress. Vessel traits were measured for clonally replicated genotypes of a unique Populus deltoides x nigra population carrying genomically defined insertions and deletions that create gene dosage variation. We found significant phenotypic variation for all traits measured (mean vessel diameter, height-corrected mean vessel diameter, vessel frequency, height-corrected vessel frequency, vessel grouping index, and mean vessel circularity), and that all traits were under genetic control and showed moderate heritability values, ranging from 0.32 to 0.53. Whole-genome scans of correlations between gene dosage and phenotypic traits identified quantitative trait loci for tree height, mean vessel diameter, height-corrected mean vessel diameter, height-corrected vessel frequency, and vessel grouping index. Our results demonstrate that vessel traits affecting hydraulic physiology are under genetic control, and both pleiotropic and trait-specific quantitative trait loci are found for these traits