Food Habits of Ermine, Mustela erminea, in a Forested Landscape

Most research pertaining to the diet of North American weasels has been conducted in agricultural areas and may not be representative of diets in forested regions. Ermine carcasses (N = 155) collected from trappers during a two-week harvest (16-30 November 1996) in forested New Brunswick were analyzed for food habits. The contents of 81 stomachs and 98 gastrointestinal tracts (N = 179) were considered as separate eating events and used in the calculation of the percent frequency of occurrence. Results suggest that soricids (28.0%), arvicolines (24.6%), and cricetines (17.3%) comprised two-thirds of their autumn diet. At a species or genus level, the Deer Mouse (Peromyscus maniculatus) (17.3%) and shrews (Sorex spp.) (28.0%) were shown to have the highest percent occurrence. Squirrels, including the Red Squirrel (Tamiasciurus hudsonicus) and the Eastern Chipmunk (Tamius striatus), comprised 11.2% of the Ermine’s diet; a value higher than has previously been reported

Breeding Densities, Biogeography, and Nest Depredation of Birds on Igloolik Island, N.W.T.

The avifauna of Igloolik Island and immediate vicinity was studied during two breeding seasons in 1985-86. This is the first study to compile an intensive record of avifaunal migration patterns and nesting activity, density and success for Igloolik Island. Data for these years are supplemented by the observations of earlier explorers and researchers. During our two seasons of survey, we recorded 40 species of birds, of which 25 nested on the island. Combining our records with previously published data, a total of 48 species have been recorded, with 30 species nesting. Several interspecies matings of gulls and the first confirmed breeding record of purple sandpiper (Calidris maritima) for the Melville Peninsula area were recorded. The density of breeding birds on Igloolik Island (28.5 pairs/sq. m) is similar to other eastern high arctic sites at that latitude. Issues related to the biogeographic comparisons of arctic sites are discussed. In late August, the eastern end of the island acts as a significant staging area for gull species, oldsquaw (Clangula hyemalis) and arctic tern (Sterna paradisaea). A combined average of 58.3% of the nests of six species were depredated. As many as 73% of red-throated loon (Gavia stellata) and 93% of arctic tern nests suffered mainly human-related egg predation.Key words: Arctic, Igloolik Island, breeding avifauna, density, interspecies matings, biogeographyRÉSUMÉ. On a étudié l’avifaune de l’île Igloolik et de son voisinage immédiat au cours de deux saisons de reproduction, en 1985 et 1986. Cette étude est la première à compiler un dossier en profondeur du comportement migratoire de l’avifaune ainsi que de l’activité, de la densité et du taux de réussite de la nidification dans l’île Igloolik. Des observations faites antérieurement par des explorateurs et des chercheurs viennent compléter les données recueillies durant l’étude. Au cours des deux années de l’étude, on a relevé 40 espèces d’oiseaux, dont 25 se reproduisaient sur l’île. Si l’on combine nos relevés avec des données publiées précédemment, 48 espèces au total ont été enregistrées, dont 30 se reproduisent sur l’île. On a observé l’accouplement de plusieurs mouettes d’espèces différentes et enregistré la première occurrence de nidification du bécasseau violet (Calidris maritima) pour la péninsule de Melville. La densité des oiseaux nicheurs sur l’île Igloolik (28,5 paires,km-’) est semblable à celle d’autres sites de l’Extrême-Arctique oriental à la même latitude. On discute de questions relatives aux comparaisons biogéographiques de sites arctiques. A la fin du mois d’août, la portion orientale de l’île fait office d’importante aire de repos pour les espèces de mouettes, le canard kakawi (Clangula byemalis) et la sterne arctique (Sterna paradisaea). Une moyenne combinée de 58,3 p. cent des nids de six espèces ont été pillés. La prédation des oeufs, principalement par l’homme, a affecté un nombre aussi élevé que 73 p. cent des nids de huarts à gorge rousse (Gavia stellata) et 93 p. cent des nids de sternes arctiques.Mots clés: Arctique, île Igloolik, avifaune reproductrice, densité, accouplements d’espèces différentes, biogéographi

Implications for the origin of dwarf early-type galaxies: a detailed look at the isolated rotating dwarf early-type galaxy CG 611, with ramifications for the Fundamental Plane's (S_K)^2 kinematic scaling and the spin-ellipticity diagram

Selected from a sample of nine, isolated, dwarf early-type galaxies (ETGs) having the same range of kinematic properties as dwarf ETGs in clusters, we use CG 611 (LEDA 2108986) to address the Nature versus Nurture debate regarding the formation of dwarf ETGs. The presence of faint disk structures and rotation within some cluster dwarf ETGs has often been heralded as evidence that they were once late-type spiral or dwarf irregular galaxies prior to experiencing a cluster-induced transformation into an ETG. However, CG 611 also contains significant stellar rotation (~20 km/s) over its inner half light radius, R_(e,maj)=0.71 kpc, and its stellar structure and kinematics resemble those of cluster ETGs. In addition to hosting a faint young nuclear spiral within a possible intermediate-scale stellar disk, CG 611 has accreted an intermediate-scale, counter-rotating gas disk. It is therefore apparent that dwarf ETGs can be built by accretion events, as opposed to disk-stripping scenarios. We go on to discuss how both dwarf and ordinary ETGs with intermediate-scale disks, whether under (de)construction or not, are not fully represented by the kinematic scaling S_0.5=sqrt{ 0.5(V_rot)^2 + sigma^2 }, and we also introduce a modified spin-ellipticity diagram, lambda(R)-epsilon(R), with the potential to track galaxies with such disks.Comment: 15 pages (includes 9 figures and an extensive 2+ page reference list

Evaluating the robustness of an active network management function in an operational environment

This paper presents the integration process of a distribution network Active Network Management (ANM) function within an operational environment in the form of a Micro-Grid Laboratory. This enables emulation of a real power network and enables investigation into the effects of data uncertainty on an online and automatic ANM algorithm's control decisions. The algorithm implemented within the operational environment is a Power Flow Management (PFM) approach based around the Constraint Satisfaction Problem (CSP). This paper show the impact of increasing uncertainty, in the input data available for an ANM scheme in terms of the variation in control actions. The inclusion of a State Estimator (SE), with known tolerances is shown to improve the ANM performance

A commentary on select 'Epistles' of Horace

Horace's first book of Epistles comprise twenty poems which purport to be written by him to persons of varying ages and stations in life. They are not real letters, but rather are so shaped as to give the flavour of a letter. However, while they are artfully contrived, there is no reason to doubt that each addressee was a real person, and it is the clear personal element which is one of their most attractive features. I have selected two epistles which well illustrate Horace's capacity to relate to other people, while at the same time revealing something of his own self. Epistle l.4- shows his concern for his contemporary and fellow poet, Tibullus, and culminates in the carpe diem advice which Horace had expressed often in his Odes 1-3, published prior to the Epistles. His invitation to Tibullus recalls the sympotic motif familiar in many Odes where reflections on the shortness and precariousness of life lead to a summons to enjoy the present positively. Sociability and friendship will bring Tibullus out of himself. Repeatedly in the Epistles we see Horace stressing the value of friendship, and it is this aspect of human relations which reveals something of the poet's own sense of values and priorities. In contrast to the whimsical and gently teasing tone of Ep. 1.4 (where Horace is dealing with a social equal and cultured figure from the literary world) to his vilicus shows Horace as the master dealing with a recalcitrant slave who is dissatisfied with his posting to the country. Horace firmly encourages him to a more reasonable view of his position and superbly shows his versatility in adapting his style and language to the level of a mere slave and social inferior. The theme of discontent with one's lot recalls several Odes, while the city versus country theme recurs in several Epistles, notably 1.7 and 1.10, it recalls one of his favourite themes of the 30's; cf. Sat. 2.6 and Epode 2 where Horace yearned for the countryside, and a life of leisured otium. Both Epistles demonstrate the range of Horace's correspondence, and his prescription for bringing his addressees to an awareness of the best way to happiness and contentment

Consumption of Bats (Myotis spp.) by Raccoons (Procyon lotor) During an Outbreak of White-Nose Syndrome in New Brunswick, Canada: Implications for Estimates of Bat Mortality

Across their range, Raccoons (Procyon lotor) will opportunistically exploit bats (Chiroptera) roosting in caves as a source of food. During a significant mortality event associated with white-nose syndrome (WNS) at a cave in eastern Canada, we estimate that Raccoons consumed 3169–3827 dead and dying Little Brown Bats (Myotis lucifugus) and Northern Long-eared Bats (M. septentrionalis) infected with white-nose syndrome, equivalent to 62.0–74.9% of the total bat mortality at this site. However, the generally small dispersal distances of Raccoons and their reduced activity during the period when bats are hibernating suggest that Raccoons are likely not a significant vector for moving the fungus associated with white-nose syndrome, Geomyces destructans, between most caves at this latitude. Nevertheless, since we show that significant numbers of bats can be consumed in hibernacula through opportunistic feeding by Raccoons, estimates of in-cave mortality due to white-nose syndrome should incorporate any evidence of consumption of bats by Raccoons and other predators

Bridging the gap between low and high mass dwarf galaxies

While the dark matter content within the most massive giant and smallest dwarf galaxies has been probed -- spanning a range of over one million in mass -- an important observational gap remains for galaxies of intermediate mass. This gap covers K band magnitudes of approximately -16 > M_K > -18 (for which dwarf galaxies have B--K ~ 2). On the high mass side of the gap are dwarf elliptical (dE) galaxies, that are dominated by stars in their inner regions. While the low mass side includes dwarf spheroidal (dSph) galaxies that are dark matter-dominated and ultra compact dwarf (UCD) objects that are star-dominated. Evolutionary pathways across the gap have been suggested but remain largely untested because the `gap' galaxies are faint, making dynamical measurements very challenging. With long exposures on the Keck telescope using the ESI instrument we have succeeded in bridging this gap by measuring the dynamical mass for five dwarf galaxies with M_K ~ -17.5 (M_B ~ --15.5). With the exception of our brightest dwarf galaxy, they possess relatively flat velocity dispersion profiles of around 20 km/s. By examining their 2D scaling relations and 3D fundamental manifold, we found that the sizes and velocity dispersions of these gap galaxies reveal continuous trends from dE to dSph galaxies. We conclude that low-luminosity dwarf elliptical galaxies are dominated by stars, not by dark matter, within their half light radii. This finding can be understood if internal feedback processes are operating most efficiently in gap galaxies, gravitationally heating the centrally-located dark matter to larger radii. Whereas external environmental processes, which can strip away stars, have a greater influence on dSph galaxies resulting in their higher dark matter fractions. Abridged.Comment: 20 pages, includes 12 figures, accepted for publication in MNRA

The combinatorics of neurite self-avoidance

During neural development in Drosophila, the ability of neurite branches to recognize whether they are from the same or different neurons depends crucially on the molecule Dscam1. In particular, this recognition depends on the stochastic acquisition of a unique combination of Dscam1 isoforms out of a large set of possible isoforms. To properly interpret these findings, it is crucial to understand the combinatorics involved, which has previously been attempted only using stochastic simulations for some specific parameter combinations. Here we present closed-form solutions for the general case. These reveal the relationships among the key variables and how these constrain possible biological scenarios