Status of High Arctic Black-Legged Kittiwake (Rissa tridactyla) Colonies in Barrow Strait, Nunavut, Canada

We used aerial survey estimates, photographic censuses, and plot counts to examine trends in the size of five black-legged kittiwake (Rissa tridactyla) colonies around Barrow Strait, eastern Nunavut, Canada, between 1972 and 2007. During these three decades, one small colony disappeared, two medium-sized colonies showed no overall trend, and one moderate and one large colony appeared to increase in size. Collectively, the number of kittiwakes breeding in this region may have increased by over 40%. Counts of kittiwakes at some colonies were markedly low in 2003, following two consecutive years of late, extensive sea ice, although overall there was no significant relationship between numbers of kittiwakes attending colonies and sea-ice extent in Barrow Strait and Lancaster Sound. It is not known why kittiwake colonies in High Arctic Canada have apparently increased while those in West Greenland and elsewhere have declined, or what factors influenced these changes.Entre 1972 et 2007, à l’aide d’estimations effectuées à partir de levés aériens, de recensements photographiques et de dénombrements, nous avons examiné les tendances caractérisant la taille de cinq colonies de mouettes tridactyles (Rissa tridactyla) dans les environs du détroit de Barrow, dans l’est du Nunavut, au Canada. Pendant ces trois décennies, une petite colonie a disparu, deux colonies de taille moyenne n’ont affiché aucune tendance générale, tandis que la taille d’une colonie de taille modérée ainsi que celle d’une colonie de grande taille ont semblé augmenter. Collectivement, le nombre de mouettes tridactyles se reproduisant dans cette région pourrait s’être accru de plus de 40 pour cent. En 2003, le nombre de mouettes tridactyles de certaines colonies était nettement bas, ce qui suivait deux années consécutives de glace de mer tardive et étendue bien que dans l’ensemble, il n’existait pas de relation importante entre le nombre de mouettes tridactyles faisant partie des colonies et l’étendue de la glace de mer dans le détroit de Barrow et le bras de mer de Lancaster. On ne sait pas pourquoi les colonies de mouettes tridactyles de l’Extrême-Arctique sembleraient avoir pris de l’ampleur, tandis que les colonies de l’ouest du Groenland et d’ailleurs se sont amincies. De plus, on ne connaît pas les facteurs qui ont influencé ces changements

The accuracy of clinician evaluation of interproximal contacts using different methods

Statement of problem. Complete seating of a single crown may not be possible if the interproximal contacts are excessively tight. Incomplete seating can lead to open margins, inflammation of the gingival tissue, and recurrent dental caries. Purpose. The purpose of this in vitro study was to determine the accuracy of 3 different methods of evaluating interproximal contacts when seating a single crown. Material and methods. Thirty-five restorative dentists practicing in the Lincoln, Nebraska, area were polled to determine the methods they used most commonly to evaluate the interproximal contacts of crowns. These dentists then evaluated the interproximal contacts of 9 anatomic contour zirconia crowns on a dentoform using 3 different methods: floss and explorer, occlusal articulating film (AccuFilm), and shim stock. Crown fit was evaluated using 1 method at a time. Each crown was recorded as either “accept” or “reject” according to the individual clinician. All data were analyzed with the McNemar test (a=.05). Results. Of the 35 restorative dentists polled, 34 identified floss and explorer, 9 identified occlusal articulating film, 3 identified shim stock, and 3 identified an occlusal spray as their method of evaluating interproximal contacts. These methods were used either alone or in conjunction with other methods. Evaluation of the in vitro data revealed that shim stock and occlusal articulating film were significantly more accurate than floss and explorer for assessing interproximal contacts in poorly fitting crowns (P Conclusions. This study showed that the floss and explorer method was the least accurate means of evaluating the interproximal fit of crowns. Shim stock provided the most accurate method of evaluating interproximal contact, and occlusal articulating film provided both high accuracy and a visible mark to facilitate adjustment. (J Prosthet Dent 2019;

The accuracy of clinician evaluation of interproximal contacts using different methods

Statement of problem. Complete seating of a single crown may not be possible if the interproximal contacts are excessively tight. Incomplete seating can lead to open margins, inflammation of the gingival tissue, and recurrent dental caries. Purpose. The purpose of this in vitro study was to determine the accuracy of 3 different methods of evaluating interproximal contacts when seating a single crown. Material and methods. Thirty-five restorative dentists practicing in the Lincoln, Nebraska, area were polled to determine the methods they used most commonly to evaluate the interproximal contacts of crowns. These dentists then evaluated the interproximal contacts of 9 anatomic contour zirconia crowns on a dentoform using 3 different methods: floss and explorer, occlusal articulating film (AccuFilm), and shim stock. Crown fit was evaluated using 1 method at a time. Each crown was recorded as either “accept” or “reject” according to the individual clinician. All data were analyzed with the McNemar test (a=.05). Results. Of the 35 restorative dentists polled, 34 identified floss and explorer, 9 identified occlusal articulating film, 3 identified shim stock, and 3 identified an occlusal spray as their method of evaluating interproximal contacts. These methods were used either alone or in conjunction with other methods. Evaluation of the in vitro data revealed that shim stock and occlusal articulating film were significantly more accurate than floss and explorer for assessing interproximal contacts in poorly fitting crowns (P Conclusions. This study showed that the floss and explorer method was the least accurate means of evaluating the interproximal fit of crowns. Shim stock provided the most accurate method of evaluating interproximal contact, and occlusal articulating film provided both high accuracy and a visible mark to facilitate adjustment. (J Prosthet Dent 2019;

Changes in Isotopic Niches across Stages of the Annual Cycle in the Arctic Tern (Sterna paradisaea)

 Arctic Terns (Sterna paradisaea) are iconic seabirds of polar latitudes, whose successful reproduction is thought to depend on local food supplies near breeding colonies. We used stable isotopes of carbon and nitrogen in eggs, blood, and feathers of terns breeding in the Canadian High Arctic to compare their isotopic niche between life history stages and between two years. The isotopic niche of terns was smaller during incubation than during pre-breeding or winter. Over two breeding seasons, isotopic profiles of Arctic Terns suggested the high importance of local, exogenous nutrient supplies to form eggs (i.e., an income breeding strategy). Our results illustrate that using stable isotopes to assess the niche of a seabird population during critical periods of its annual cycle could be an essential tool in determining the influence that local forage conditions have on breeding decisions, especially for species that mostly rely on exogenous sources of nutrients and energy for egg production. La sterne arctique (Sterna paradisaea) est un oiseau de mer emblématique des latitudes polaires, dont la reproduction réussie dépendrait de l’approvisionnement en aliments à proximité des colonies de nidification. Nous avons utilisé les isotopes stables du carbone et de l’azote provenant des oeufs, du sang et des plumes des sternes se reproduisant dans l’Extrême-Arctique canadien pour comparer leur niche isotopique entre divers stades de leur cycle biologique ainsi qu’entre deux années différentes. La niche isotopique des sternes était plus petite pendant l’incubation qu’avant la reproduction ou que pendant l’hiver. Au cours des deux saisons de reproduction, les profils isotopiques des sternes arctiques ont laissé entrevoir la grande importance d’approvisionnements en nutriments locaux et exogènes pour la formation des oeufs (soit une stratégie de reproduction à approvisionnement). Nos résultats illustrent que l’utilisation des isotopes stables pour évaluer la niche de la population d’oiseaux de mer pendant les périodes critiques de leur cycle annuel pourrait constituer un outil essentiel pour déterminer l’influence qu’ont les conditions d’alimentation locales sur les décisions de reproduction, surtout pour les espèces qui dépendent de sources d’énergie et de nutriments exogènes pour la production des oeufs

Incidental Observations of Birds in the Vicinity of Hell Gate Polynya, Nunavut: Species, Timing, and Diversity

Our knowledge of the distribution of Arctic birds and how their ranges may be responding to environmental changes in the Canadian Arctic is limited. We gathered five years of species observation data from three sites in the Hell Gate – Cardigan Strait Polynya (Cape Vera, St. Helena Island, and Devil Island) to create an inventory of avian species observed in the polynya, and we compared it to previous observations made at our sites and other sites throughout the Arctic. We examined species diversity measurements over time to suggest possible effects of the polynya on the timing of spring arrival of breeding and migrant species. Of the 39 species observed during our study, 12 were local breeders. Our records provide the northernmost observations for eight species. Species diversity index values at St. Helena Island peaked quickly in mid-June and stabilized by late June, reflecting the arrival and dispersal of migrating species relatively early in the season. These data highlight the importance of the open-water feeding habitat of the polynya not only for breeding birds, but also for migrants.Nos connaissances de la distribution des oiseaux de l’Arctique et de la façon dont leurs parcours sont adaptés en fonction des changements environnementaux de l’Arctique canadien sont restreintes. Nous avons rassemblé les données d’observation d’espèces diverses échelonnées sur cinq ans à partir de trois emplacements de la polynie de Hell Gate – Cardigan Strait (cap Vera, île St. Helena et île Devil) dans le but de dresser l’inventaire des espèces aviaires observées dans la polynie, puis nous les avons comparées aux observations faites antérieurement à nos emplacements de même qu’à d’autres emplacements de l’Arctique. Nous avons examiné les mesures de la diversité des espèces au fil du temps afin de pouvoir suggérer les effets possibles de la polynie sur le moment de l’arrivée du printemps des espèces nicheuses et des espèces migrantes. Au nombre des 39 espèces ayant fait l’objet de notre étude, 12 étaient des oiseaux nicheurs de la région. Nos données constituent les observations prélevées les plus au nord pour huit des espèces. Les valeurs de l’indice de la diversité des espèces à l’île St. Helena ont atteint leur sommet à la mi-juin, puis se sont stabilisées vers la fin juin, ce qui était le reflet de l’arrivée et de la dispersion d’espèces migrantes relativement tôt dans la saison. Ces données font ressortir l’importance de l’habitat alimentaire en eaux libres de la polynie, non seulement pour les oiseaux nicheurs mais également pour les oiseaux migrants

Isolation and Characterization of Precise Dye/Dendrimer Ratios

Fluorescent dyes are commonly conjugated to nanomaterials for imaging applications using stochastic synthesis conditions that result in a Poisson distribution of dye/particle ratios and therefore a broad range of photophysical and biodistribution properties. We report the isolation and characterization of generation 5 poly(amidoamine) (G5 PAMAM) dendrimer samples containing 1, 2, 3, and 4 fluorescein (FC) or 6‐carboxytetramethylrhodamine succinimidyl ester (TAMRA) dyes per polymer particle. For the fluorescein case, this was achieved by stochastically functionalizing dendrimer with a cyclooctyne “click” ligand, separation into sample containing precisely defined “click” ligand/particle ratios using reverse‐phase high performance liquid chromatography (RP‐HPLC), followed by reaction with excess azide‐functionalized fluorescein dye. For the TAMRA samples, stochastically functionalized dendrimer was directly separated into precise dye/particle ratios using RP‐HPLC. These materials were characterized using 1 H and 19 F NMR spectroscopy, RP‐HPLC, UV/Vis and fluorescence spectroscopy, lifetime measurements, and MALDI. High definition : Two approaches for the formation of generation 5 PAMAM samples containing precise dye/dendrimer ratios are presented. The first approach, using direct separation based on dye hydrophobicity, generated a set of TAMRA‐containing dendrimers, and the second, using click chemistry, generated a set of fluorescein‐containing dendrimer (see figure).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106970/1/chem_201304854_sm_miscellaneous_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/106970/2/4638_ftp.pd

G313.3+00.3: A New Planetary Nebula discovered by the Australia Telescope Compact Array and the Spitzer Space Telescope

We present a new planetary nebula, first identified in images from the Australia Telescope Compact Array, although not recognized at that time. Recent observations with the Spitzer Space Telescope during the GLIMPSE Legacy program have rediscovered the object. The high-resolution radio and infrared images enable the identification of the central star or its wind, the recognition of the radio emission as thermal, and the probable presence of polycylic aromatic hydrocarbons in and around the source. These lead to the conclusion that G313.3+00.3 is a planetary nebula. This object is of particular interest because it was discovered solely through radio and mid-infrared imaging, without any optical (or near-infrared) confirmation, and acts as a proof of concept for the discovery of many more highly extinguished planetary nebulae. G313.3+00.3 is well-resolved by both the instruments with which it was identified, and suffers extreme reddening due to its location in the Scutum-Crux spiral arm.Comment: 18 pages, LaTeX (aastex), incl. 8 PostScript (eps) figures and 1 table. Accepted by ApJ (Part 1

Variable sea-ice conditions influence trophic dynamics in an Arctic community of marine top predators

Sea-ice coverage is a key abiotic driver of annual environmental conditions in Arctic marine ecosystems and could be a major factor affecting seabird trophic dynamics. Using stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in eggs of thick-billed murres (Uria lomvia), northern fulmars (Fulmarus glacialis), glaucous gulls (Larus hyperboreus), and black-legged kittiwakes (Rissa tridactyla), we investigated the trophic ecology of prebreeding seabirds nesting at Prince Leopold Island, Nunavut, and its relationship with sea-ice conditions. The seabird community of Prince Leopold Island had a broader isotopic niche during lower sea-ice conditions, thus having a more divergent diet, while the opposite was observed during years with more extensive sea-ice conditions. Species' trophic position was influenced by sea ice; in years of lower sea-ice concentration, gulls and kittiwakes foraged at higher trophic levels while the opposite was observed for murres and fulmars. For murres and fulmars over a longer time series, there was no evidence of the effect of sea-ice concentration on species' isotopic niche. Results suggest a high degree of adaptation in populations of high Arctic species that cope with harsh and unpredictable conditions. Such different responses of the community isotopic niche also show that the effect of variable sea-ice conditions, despite being subtle at the species level, might have large

Recommended best practices for plastic and litter ingestion studies in marine birds: Collection, processing, and reporting

doi: 10.1139/facets-2018-0043Marine plastic pollution is an environmental contaminant of significant concern. There is a lack of consistency in sample collection and processing that continues to impede meta-analyses and largescale comparisons across time and space. This is true for most taxa, including seabirds, which are the most studied megafauna group with regards to plastic ingestion research. Consequently, it is difficult to evaluate the impacts and extent of plastic contamination in seabirds fully and accurately, and to make inferences about species for which we have little or no data. We provide a synthesized set of recommendations specific for seabirds and plastic ingestion studies that include best practices in relation to sample collection, processing, and reporting, as well as highlighting some “cross-cutting” methods. We include guidance for how carcasses, regurgitations, and pellets should be handled and treated to prevent cross-contamination, and a discussion of what size class of microplastics can be assessed in each sample type. Although we focus on marine bird samples, we also include standardized techniques to remove sediment and biological material that are generalizable to other taxa. Lastly, metrics and data presentation of ingested plastics are briefly reviewed in the context of seabird studies.Copyright: © 2019 Provencher et al. This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The attached file is the published pdf