Population development and breeding success of Dark-bellied Brent Geese Branta b. bernicla from 1991-2011

The Dark-bellied Brent Goose Branta bernicla bernicla is the largest of the six Brent Goose populations, which collectively number around 600,000 birds globally. After a major decline to 16,500 geese in 1958, numbers recovered during the 1970s and 1980s to a peak of c. 330,000 individuals between 1992 and 1994. From 1994 onwards the population declined again to 200,000–250,000. This decline has been attributed to poor breeding, associated with faltering cycles of Siberian Brown Lemming Lemmus sibiricus (predominantly) and Palearctic Collared Lemming Dicrostonyx torquatus abundance on the breeding grounds on the Taimyr Peninsula, where lemmings are a main food resource for potential predators of goslings. Darkbellied Brent Geese only breed well in peak lemming years (Summers & Underhill 1991), and this usually occurs every three years, but the frequent failure since 1994 of lemming numbers to peak (except in 2005) has resulted in the absence of very good breeding years for the geese (Nolet et al. 2013). The mid-winter distribution has shown a marked shift towards France over the last decade. France currently supports 50% of the population in January, Great Britain 35–40%, the Netherlands 15–20%, and Germany and Denmark 2%. In spring, almost the entire population gathers in the Wadden Sea, leaving only 4% of the population in Great Britain, and virtually none in France, with the Dutch part of the Wadden Sea supporting 40–45%, the German section 45–50% and Denmark 6%

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

MÖSSBAUER SPECTROSCOPIC STUDIES OF Ni CATALYSTS : PARTICLE SIZE DETERMINATION AND EFFECT OF HYDROGEN CHEMISORPTION

Les propriétés magnétiques de microcristaux de Ni supportés en silica ont été étudiées au moyen de la spectroscopie Mössbauer. La granulométrie est estimée d'après les variations du spectre à 78 K avec le champ magnétique appliqué. On a trouvé que le moment magnétique des particules et la constante d'énergie anisotrope décroissent au cours de l'adsorption d'hydrogène.The magnetic properties of silica supported Ni microcrystals have been studied by use of Mössbauer spectroscopy. From the field dependence of the spectra at 78 K the particle size is estimated. It is found that both the magnetic moment of the particles and the anisotropy energy constant decrease when hydrogen is chemisorbed

MÖSSBAUER STUDIES OF CHEMISORPTION OF CO AND H2 ON PARTICLES OF METALLIC IRON

No abstract availabl

X-RAY ABSORPTION SPECTROSCOPY STUDY OF Cu-BASED METHANOL CATALYSTS. 2. REDUCED STATE

La spectroscopie d'absorption aux rayons X (XAS) faite in situ a été utilisée pour éclaircir la constitution de catalyseurs de méthanol binaires Cu-Zn et ternaires Cu-Zn-Al dans l'état réduit. Les résultats de la XAS des catalyseurs binaires montrent des propriétés d'une phase de cuivre métallique après réduction à une température de 220°C. Il a été constaté que la constitution des catalyseurs ternaires réduits dépend d'une manière cruciale et de la concentration de cuivre et de la température de réduction. Au contraire des catalyseurs binaires, la réduction à 220°C ne mène à aucun changement significatif comparée à l'état calciné. A 260°C la réduction de la phase de cuivre l'état métallique se fait, et il a été remarqué que la grandeur des crystallites ou le degré d'ordre du cuivre métallique augmente avec la teneur en cuivre.In situ X-ray absorption spectroscopy (XAS) has been used to elucidate the structure of binary Cu-Zn and ternary Cu-Zn-Al methanol catalysts in the reduced state. The XAS results of the binary catalysts show the features of a metallic Cu phase after reduction at 220°C. The structure of the reduced ternary catalysts is found to depend critically on both the copper concentration and the reduction temperature. In contrast to the binary catalysts, reduction at 220°C does not result in any significant change as compared with the calcined state. At 260°C, reduction of the copper phase to the metallic state is accomplished, and the crystallite size or degree of order of the metallic Cu is found to increase with the copper content

MÖSSBAUER STUDIES OF HYDRODESULPHURIZATION CATALYSTS : COMPARISON OF SOURCE AND ABSORBER EXPERIMENTS

On a comparé des spectres Mössbauer de catalyseurs Fe-Mo avec ceux de catalyseurs Co-Mo dopés de 57Co afin de déterminer les sites et les états chimiques des éléments 3d dans ces catalyseurs, et afin d'estimer l'influence du processus de décroissance radioactive sur les spectres des catalyseurs dopés de 57Co. Les résultats indiquent que dans les états activés des catalyseurs, Co et Fe sont dans les mêmes sites et avec les mêmes états de valence.Mössbauer spectra of Fe-Mo and 57Co doped Co-Mo catalysts are compared in order to determine the sites and chemical states of the 3d elements in these catalysts and to estimate the influence of the decay process on the spectra of the 57Co doped catalysts. The results indicate that in the activated states of the catalysts Co and Fe are present in similar sites and in similar valence states