Heart rate and energy expenditure of incubating wandering albatrosses: basal levels, natural variation, and the effects of human disturbance

We studied the changes in heart rate (HR) associated with metabolic rate of incubating and resting adult wandering albatrosses (Diomedea exulans) on the Crozet Islands. Metabolic rates of resting albatrosses fitted with external HR recorders were measured in a metabolic chamber to calibrate the relationship between HR and oxygen consumption (V̇O2) (V̇O2=0.074×HR+0.019, r2=0.567, P\u3c0.001, where V̇O2 is in ml kg–1 min–1 and HR is in beats min–1). Incubating albatrosses were then fitted with HR recorders to estimate energy expenditure of albatrosses within natural field conditions. We also examined the natural variation in HR and the effects of human disturbance on nesting birds by monitoring the changes in HR. Basal HR was positively related to the mass of the individual. The HR of incubating birds corresponded to a metabolic rate that was 1.5-fold (males) and 1.8-fold (females) lower than basal metabolic rate (BMR) measured in this and a previous study. The difference was probably attributable to birds being stressed while they were held in the metabolic chamber or wearing a mask. Thus, previous measurements of metabolic rate under basal conditions or for incubating wandering albatrosses are likely to be overestimates. Combining the relationship between HR and metabolic rate for both sexes, we estimate that wandering albatrosses expend 147 kJ kg–1 day–1 to incubate their eggs. In addition, the cost of incubation was assumed to vary because (i) HR was higher during the day than at night, and (ii) there was an effect of wind chill (\u3c0°C) on basal HR. The presence of humans in the vicinity of the nest or after a band control was shown to increase HR for extended periods (2–3 h), suggesting that energy expenditure was increased as a result of the disturbance. Lastly, males and females reacted differently to handling in terms of HR response: males reacted more strongly than females before handling, whereas females took longer to recover after being handled

The 1958–2009 Greenland ice sheet surface melt and the mid-tropospheric atmospheric circulation

peer reviewedaudience: researcherIn order to assess the impact of the mid-tropospheric circulation over the Greenland ice sheet (GrIS) on surface melt, as simulated by the regional climate model MAR, an automatic Circulation type classification (CTC) based on 500 hPa geopotential height from reanalyses is developed. General circulation correlates significantly with the surface melt anomalies for the summers in the period 1958–2009. The record surface melt events observed during the summers of 2007–2009 are linked to the exceptional persistence of atmospheric circulations favouring warm air advection. The CTC emphasizes that summer 500 hPa circulation patterns have changed since the beginning of the 2000s; this process is partly responsible for the recent warming observed over the GrIS

Évaluation des doses d'irradiation aux organes en scanographie pédiatrique

Purpose. To estimate radiation doses from routine pediatric CT scans (body) and to propose dose reduction protocols. Materiel and methods. Study performed with a phantom equivalent to the body of 5 year old child with evaluation of doses delivered to breast, gonads, bone marrow (sternum, T12) and thyroid for GT examinations of the chest, abdomen, pelvis and spine. Extrapolation is made to estimate the doses for 1 year old and 10 year old children. Finally, dose reduction protocols are evaluated. Results. CT of the chest delivers significant doses to breast tissue and bone marrow, CT of the abdomen and pelvis delivers significant doses to the ovaries and CT pf the spine delivers significant doses to thyroid and bone marrow. Optimization can be achieved without degradation of the image quality, by reducing Kv and mAs within reasonable limits. This study may be used in order to evaluate the doses delivered by multi-detector CT units. © Éditions Françaises de Radiologie, 2005.Objectifs Déterminer la dose organe délivrée pour les scanners pédiatriques courants du tronc et proposer une réduction des doses. Matériel et méthode Une étude sur fantôme correspondant au corps d’un enfant de 5 ans a été menée afin de mesurer la dose délivrée aux gonades, à la moelle osseuse (sternum T12) et à la thyroïde pour les scanners thoraciques, abdominaux, du bassin et du rachis. On a tenté d’optimiser les doses en réduisant les paramètres. Résultats Les doses organes délivrées sont assez significatives pour un scanner thoracique, aux seins et aux sites hématopoïétiques, la dose aux ovaires est importante pour les scanners abdomino-pelviens et le scanner du rachis est très irradiant pour la thyroïde ainsi que pour la moelle rouge. L’optimisation peut se faire sans dégradation de la qualité de l’image en diminuant KV et mAs dans des limites raisonnables. Cette étude doit servir de base à l’évaluation des doses délivrées par les scanners nouvelle génération

Radiative lifetimes of 3p ²PoJ in Boron-like Nitrogen

info:eu-repo/semantics/nonPublishe

Sobre os tipos de Hesperiidae descritos por Roeber (Lepidoptera)

<abstract language="eng">Comments on the systematic position and synonymy of the Hesperiidae described by J. Roeber are presented. The Syn. n. are the following: Jemadia gigantea Roeber, 1925 of Nosphistia zonara (Hewitson, 1866), Pyrrhopyga josepha Ploetz, 1879 of Hegesippe luteizona (Mabille, 1877), Phocides palaemonides Roeber, 1925 of Phocides palemon palemon (Cramer, 1777), Phocides xenocrates Bell, 1935 of Phocides vulcanides Roeber, 1925, Phocides parvus Roeber, 1925 of Phocides pialia pialia (Hewitson, 1857), Thymele aulicusi Roeber, 1925 of Astraptes enotrus (Cramer, 1781), Pythonides zonula Mabille, 1889 of Paches loxus loxus (Westwood, 1852), Thespieus chlorocephala Roeber, 1925 of Thespieus lutetia (Hewitson, 1866), Xeniades cecropteroides Roeber, 1925 of Niconiades caeso (Mabille, 1891) and Thracides nanea chiricana Roeber, 1925 of Thracides nanea nanea (Hewtson, 1867). Metron leucogaster leucomelas (Roeber, 1925) is a Comb. n. and a Stat. n. for Zenis leucomelas. Lectotypes are designated for the following species or subspecies: Mimoniades hemitaenia Roeber, 1925, Mimoniades inaequalis Roeber, 1925, Amenis similis Roeber, 1925, Mysoria erythrostigma Roeber, Myscelus nobilis meridionalis Roeber, 1925, Phocides iocularis Roeber, 1925, Phocides parvus Roeber, 1925, Polygonus amyntas pallida Roeber, 1925, Thymele albifasciatus Roeber, 1925, Thymele subfasciatus Roeber, 1925, Thymele aulicus Roeber, 1925, Phyrrhocalles kruegeri Roeber, 1925, Vettius phyllides Roeber, 1925 and Xeniades cecropteroides Roeber, 1925

Structural basis of siRNA recognition by TRBP double-stranded RNA binding domains

The accurate cleavage of pre-micro(mi)RNAs by Dicer and mi/siRNA guide strand selection are important steps in forming the RNA-induced silencing complex (RISC). The role of Dicer binding partner TRBP in these processes remains poorly understood. Here, we solved the solution structure of the two N-terminal dsRNA binding domains (dsRBDs) of TRBP in complex with a functionally asymmetric siRNA using NMR, EPR, and single-molecule spectroscopy. We find that siRNA recognition by the dsRBDs is not sequence-specific but rather depends on the RNA shape. The two dsRBDs can swap their binding sites, giving rise to two equally populated, pseudo-symmetrical complexes, showing that TRBP is not a primary sensor of siRNA asymmetry. Using our structure to model a Dicer-TRBP-siRNA ternary complex, we show that TRBP's dsRBDs and Dicer's RNase III domains bind a canonical 19 base pair siRNA on opposite sides, supporting a mechanism whereby TRBP influences Dicer-mediated cleavage accuracy by binding the dsRNA region of the pre-miRNA during Dicer cleavage