Relationship of body size to time of nesting and mate preference in the Ring-billed Gull (Larus delawarensis)

The first part of this thesis investigated the relationship between time of nesting and body size in Ring-billed Gulls (Larus delawarensis). There were no significant differences in skeletal measurements among birds from early, peak, post-peak, and late nesting periods. Discriminant function analysis failed to classify individuals by overall body size into groups defined by the periods in which they initiated nesting activities. Body condition was significantly lower in late-breeding birds compared to those from other nesting periods. Although there was a direct relationship between timing of nesting and body condition, no such relationship held with body size or individual skeletal variables. The second part of this thesis examined the relationship between body size and mate preference in Ring-billed Gulls. A total of 16 skeletal measurements were taken on each bird from 108 mated pairs of gulls. Variance in skull and bill measures was significantly lower between mates than in randomly generated pairs. However, correlation coefficients for all single skeletal characters between mates were low. High correlations were found between mates in body condition and fresh weight but not in random pairs. A significant positive correlation existed between overall body size within mated pairs but not within random pairs. The results indicate that Ring-billed Gulls mate assortatively on the basis of body condition and to a lesser degree by overall body size. I postulate, however, that this assortative mating is not the result of active choice of similar-sized or quality mates. Ring-bill probably attempt to obtain the best quality mate possible, but because of the presence of higher quality competitors, actually obtain mates of comparable size and quality. This type of mate choice would appear as assortative mating in studies undertaken after mate selection was completed

Malaxis monophyllos var. brachypoda, One-leaved Malaxis, new to the Northwest Territories, Canada

The orchid, Malaxis monophyllos var. brachypoda, is reported from Yellowknife, this being the first record for the Northwest Territories and an extension of about 650 kilometers to the northeast from the nearest population in northern British Columbia

Aerial Surveys Do Not Reliably Survey Boreal-nesting Shorebirds

Aerial surveys have been used as a method for surveying boreal-nesting shorebirds, which breed in difficult-to-access terrain; however, the fraction of breeding birds observed from the air is unknown. We investigated rates of detection by conducting simultaneous air and ground surveys for shorebirds at three sites in the boreal forest of the Northwest Territories, Canada, in 2007. Helicopter surveys included both pond-based surveys where the helicopter flew around the perimeter of each wetland and transect-based surveys where observers recorded birds seen on line transects. Ground surveys involved intensive observation, territory mapping and nest searching in 5 km2 of plots over a period of 5-6 weeks. Shorebird densities observed from the helicopter were highest near large bodies of water. No shorebirds were observed over closed forest despite breeding densities on ground surveys being highest in closed forest. Detection rates were very low, varied among species and aerial survey types, and were inconsistent over time. Ground-based observations showed that the shorebirds often did not flush in response to the helicopter passing overhead. Owing to poor rates of detection, we conclude that helicopter surveys are not an appropriate method for surveying breeding shorebirds in boreal habitats, but may have some utility for monitoring birds' use of stop-over locations

Motivation, Justification, Normalization: Talk Strategies Used by Canadian Medical Tourists Regarding Their Choices to Go Abroad for Hip and Knee Surgeries

Contributing to health geography scholarship on the topic, the objective of this paper is to reveal Canadian medical tourists’ perspectives regarding their choices to seek knee replacement or hip replacement or resurfacing (KRHRR) at medical tourism facilities abroad rather than domestically. We address this objective by examining the ‘talk strategies’ used by these patients in discussing their choices and the ways in which such talk is co-constructed by others. Fourteen interviews were conducted with Canadians aged 42-77 who had gone abroad for KRHRR. Three types of talk strategies emerged through thematic analysis of their narratives: motivation, justification, and normalization talk. Motivation talk referenced participants’ desires to maintain or resume physical activity, employment, and participation in daily life. Justification talk emerged when participants described how limitations in the domestic system drove them abroad. Finally, being a medical tourist was talked about as being normal on several bases. Among other findings, the use of these three talk strategies in patients’ narratives surrounding medical tourism for KRHRR offers new insight into the language-health-place interconnection. Specifically, they reveal the complex ways in which medical tourists use talk strategies to assert the soundness of their choice to shift the site of their own medical care on a global scale while also anticipating, if not even guarding against, criticism of what ultimately is their own patient mobility. These talk strategies provide valuable insight into why international patients are opting to engage in the spatially explicit practice of medical tourism and who and what are informing their choices

Quantifying abundance and distribution of native and invasive oysters in an urbanised estuary

© 2016 The Author(s). Journal compilation, 2016 REABIC. Human activities have modified the chemical, physical and biological attributes of many of the world’s estuaries. Natural foreshores have been replaced by artificial habitats and non-indigenous species have been introduced by shipping, aquaculture, and as ornamental pets. In south east Australia, the native Sydney rock oyster Saccostrea glomerata is threatened by pollution, disease and competition from the invasive Pacific oyster Crassostrea gigas. This study assessed the abundance (as number m-2), size, and distribution of both invasive and native oyster species at 32 sites in the heavily urbanised Port Jackson Estuary, Australia. We tested the hypotheses that there would be: (1) a difference in the proportion of C. gigas and S. glomerata among locations; (2) a greater proportion of C. gigas on artificial compared to natural substrates; (3) a greater numbers of all oysters, with differing size characteristics, on artificial compared to natural substrates; and (4) that the abundance and size of all oysters would vary among locations along an environmental gradient. Environmental variables included distance from the estuary mouth and salinity. We found the abundance and size of all oysters differed among locations; smaller oysters occurred at greater abundances near the mouth of the estuary. Abundance was also higher on artificial, than on natural substrate. Habitat type, however, had no effect on which species of oyster was present. In contrast, distance from the estuary mouth strongly influenced the relative proportion of the two species. The invasive C. gigas comprised 16% of the oysters sampled, and up to 85% at some of the upper estuary sites. As predicted, C. gigas was more abundant at locations in the bay ends and upper channel of the estuary; it was also larger in size than the native S. glomerata. This is the first assessment of oyster distribution in Port Jackson and provides a solid base for monitoring changes in the estuarine distribution of a globally invasive pest

Variable-order fractional master equation and clustering of particles: non-uniform lysosome distribution

In this paper, we formulate the space-dependent variable-order fractional master equation to model clustering of particles, organelles, inside living cells. We find its solution in the long time limit describing non-uniform distribution due to a space dependent fractional exponent. In the continuous space limit, the solution of this fractional master equation is found to be exactly the same as the space-dependent variable-order fractional diffusion equation. In addition, we show that the clustering of lysosomes, an essential organelle for healthy functioning of mammalian cells, exhibit space-dependent fractional exponents. Furthermore, we demonstrate that the non-uniform distribution of lysosomes in living cells is accurately described by the asymptotic solution of the space-dependent variable-order fractional master equation. Finally, Monte Carlo simulations of the fractional master equation validate our analytical solution.Comment: arXiv admin note: text overlap with arXiv:1902.0308

Chandra Observation of the Globular Cluster NGC 6440 and the Nature of Cluster X-ray Luminosity Functions

As part of our campaign to determine the nature of the various source populations of the low-luminosity globular cluster X-ray sources, we have obtained a Chandra X-ray Observatory ACIS-S3 image of the globular cluster NGC 6440. We detect 24 sources to a limiting luminosity of ~2 times 10^31 erg/s (0.5-2.5keV) inside the cluster's half-mass radius, all of which lie within ~2 core radii of the cluster center. We also find excess emission in and around the core which could be due to unresolved point sources. Based upon X-ray luminosities and colors, we conclude that there are 4-5 likely quiescent low-mass X-ray binaries and that most of the other sources are cataclysmic variables. We compare these results to Chandra results from other globular clusters and find the X-ray luminosity functions differ among the clusters.Comment: 9 pages, 4 figures, accepted by ApJ, minor changes, added table of clusters' physical parameter

Nurses’ decision-making around gastric residual volume measurement in adult intensive care: a four-centre survey

Background: Despite increasing evidence of the potential inaccuracy and unwarranted practice of regular gastric residual volume (GRV) measurement in critically in adults, this practice persists within the United Kingdom.Aim: To explore adult intensive care nurses’ decision-making around the practice of gastric residual volume measurement to guide enteral feeding.Methods: A cross sectional 16 item electronic survey in four adult intensive care units in England and Wales.Results: Two hundred and seventy-three responses were obtained across four intensive care units with acceptable response rates for most [Unit 1 74 /127 = 58.2%; Unit 2 87/129 =67.4%; Unit 3 77/120= 64.1%; Unit 4 35/168 = 20.8%]. Most (243/273 (89%) reported measuring GRV 4-6 hourly, with most (223/273 82%) reporting that the main reason was to assess feed tolerance or intolerance and 37/273 (13.5%) saying their unit protocol required it. In terms of factors affecting decision-making, volume obtained was the most important factor, followed by the condition of the patient, with aspirate colour and appearance less important. When asked how they would feel about not measuring gastric residual volume routinely, the majority (78.2%) of nurses felt worried (140/273 = 51.2%) or very worried (74/273 = 27%).Conclusions: Factors affecting the nurses’ decision making around gastric residual volume were based on largely on fear of risk (around vomiting and pulmonary aspiration) and compliance with unit protocols. Relevance to clinical practice: Despite increasing evidence suggesting it is unnecessary, nurses’ beliefs around the value of this practice persist and it continues to be embedded into unit protocols around feeding.<br/