The Breeding Distribution and Current Population Status of the Ivory Gull in Canada

Aerial surveys were conducted in the eastern Canadian High Arctic from 1982 to 1985 to determine the distribution and size of breeding populations of the ivory gull (Pagophila eburnea). The known Canadian population is confined to Ellesmere, Devon, Seymour, Baffin and Perley islands. Two major concentrations of ivory gull colonies exist, one among the granitic nunataks of southeastern Ellesmere Island and the other on the sedimentary plateaus of the Brodeur Peninsula of Baffin Island. The size of breeding groups varies greatly from 4 to over 300 adult gulls. Breeding colonies are typified by their inland, remote and desolate locations and virtual absence of other animal species. We suggest that there is a single Canadian population of ivory gulls whose adult cohort contains over 2400 birds. The small number of leg band recoveries and retrapping of banded birds indicates that individuals can live at least 15 years. One-year-old ivory gulls were not seen at the colonies or on adjacent waters, and their location during summer remains unknown.Key words: ivory gull, Pagophila eburnea, arctic breeding populations, nunataks, polynyas On a effectué des relevés aériens dans la partie est de l'Extrême-Arctique canadien de 1982 à 1985 pour établir la distribution et la taille des populations de mouettes blanches (Pagophila eburnea) qui se reproduisent. La population canadienne que l'on connaît habite seulement les îles Ellesmere, Devon, Seymour, Baffin et Perley. Il y a deux endroits importants où se concentrent les colonies de mouettes blanches, l'une parmi les nunataks granitiques du sud-est de l'île Ellesmere, et l'autre sur les plateaux sédimentaires de la presqu'île Brodeur dans l'île Baffin. La taille des groupes qui se reproduisent varie grandement, allant de 4 à plus de 300 oiseaux adultes. Les colonies d'animaux qui se reproduisent sont caractérisées par leur aire de nidification isolée, loin à l'intérieur des terres, et par l'absence virtuelle d'autres espèces animales. Notre opinion est qu'il existe une seule population canadienne de mouettes blanches, dont l'ensemble des adultes compte plus de 2400 oiseaux. Le petit nombre de bagues récupérées et d'oiseaux bagués avoisinantes, et l'endroit où elles se tiennent reste inconnu. Mots clés : mouette blanche, Pagophila eburnea, populations qui se reproduisent dans l'Arctique, nunataks, polynie

Thermodynamic and Tunneling Density of States of the Integer Quantum Hall Critical State

We examine the long wave length limit of the self-consistent Hartree-Fock approximation irreducible static density-density response function by evaluating the charge induced by an external charge. Our results are consistent with the compressibility sum rule and inconsistent with earlier work that did not account for consistency between the exchange-local-field and the disorder potential. We conclude that the thermodynamic density of states is finite, in spite of the vanishing tunneling density of states at the critical energy of the integer quantum Hall transition.Comment: 5 pages, 4 figures, minor revisions, published versio

The use of dexamethasone in women with preterm premature rupture of membranes - A multicentre, double-blind, placebocontrolled, randomised trial

No Abstract

Potential of microbiome-based solutions for agrifood systems

Host-associated microbiomes are central to food production systems and human nutrition and health. Harnessing the microbiome may help increase food and nutrient security, enhance public health, mitigate climate change and reduce land degradation. Although several microbiome solutions are currently under development or commercialized in the agrifood, animal nutrition, biotechnology, diagnostics, pharmaceutical and health sectors , fewer products than expected have been successfully commercialized beyond food processing, and fewer still have achieved wider adoption by farming, animal husbandry and other end-user communities. This creates concerns about the translatability of microbiome research to practical applications. Inconsistent efficiency and reliability of microbiome solutions are major constraints for their commercialization and further development, and demands urgent attention

Coral Identification Guide NAFO Area

Accurate reporting of benthic corals is increasingly important for mapping distributions and for the continued development of sustainable fisheries under the ecosystem approach. This coral identification guide is intended to help those on-board commercial and research fishing vessels to identify and record the various species of coral likely to be commonly encountered in fishing trawls. The guide is clear and simple to use, and will provide names to the majority of these beautiful bottomdwelling animals. The photographs are typically of caught specimens taken on the deck, as this gives the best picture of what is actually seen. Sadly, we rarely personally see corals in their natural habitat, except by looking at films and photos taken by deep underwater cameras

Spectroscopy of the proton emitter 109I

Excited states in the proton-unbound nucleus 109I were populated using the 54Fe(58Ni,p2n) reaction at a beam energy of 220 MeV. Gamma rays in 109I were identified using the recoil-decay tagging technique. The analysis of proton-correlated gg coincidence data produced the yrast decay sequence in 109I, which can be tentatively assigned as built on the h11/2 proton state based on systematic trends in the neighboring isotopes. This sequence is completely different from that reported previously. A comparison of the h11/2 band in 109I with those in heavier iodines shows that 109I continues the trend of decreasing quadrupole deformation with decreasing neutron number

Local Strain Heterogeneity Influences the Optoelectronic Properties of Halide Perovskites

Halide perovskites are promising semiconductors for optoelectronics, yet thin films show substantial microscale heterogeneity. Understanding the origins of these variations is essential for mitigating parasitic losses such as non-radiative decay. Here, we probe the structural and chemical origins of the heterogeneity by utilizing scanning X-ray diffraction beamlines at two different synchrotrons combined with high-resolution transmission electron microscopy to spatially characterize the crystallographic properties of individual micrometer-sized perovskite grains in high-quality films. We reveal new levels of heterogeneity on the ten-micrometer scale (super-grains) and even ten-nanometer scale (sub-grain domains). By directly correlating these properties with their corresponding local time-resolved photoluminescence properties, we find that regions showing the greatest luminescence losses correspond to strained regions, which arise from enhanced defect concentrations. Our work reveals remarkably complex heterogeneity across multiple length scales, shedding new light on the defect tolerance of perovskites

In situ simultaneous photovoltaic and structural evolution of perovskite solar cells during film formation

Metal-halide perovskites show remarkably clean semiconductor behaviour, as evidenced by their excellent solar cell performance, in spite of the presence of many structural and chemical defects. Here, we show how this clean semiconductor performance sets in during the earliest phase of conversion from the metal salts and organic-based precursors and solvent, using simultaneous in situ synchrotron X-ray and in operando current–voltage measurements on films prepared on interdigitated back-contact substrates. These structures function as working solar cells as soon as sufficient semiconductor material is present across the electrodes. We find that at the first stages of conversion from the precursor phase, at the percolation threshold for bulk conductance, high photovoltages are observed, even though the bulk of the material is still present as precursors. This indicates that at the earliest stages of perovskite structure formation, the semiconductor gap is already well-defined and free of sub-gap trap states. The short circuit current, in contrast, continues to grow until the perovskite phase is fully formed, when there are bulk pathways for charge diffusion and collection. This work reveals important relationships between the precursors conversion and device performance and highlights the remarkable defect tolerance of perovskite materials