Devon Island Programs, 1972-1973

From April 1972 through the 1973 field season, the Arctic Institute's research base on the northeast coast of Devon Island (75°40'N, 84°40'W) will be the seat of operations for scores of investigators and their field assistants. The major research program continues to be a large integrated tundra ecosystem study sponsored by the Canadian International Biological Program (IBP). The Base Camp is also being used by groups of researchers from the Canadian Wildlife Survey, and from the Polar Continental Shelf Project. The two AINA-sponsored projects are summarized below. ... During the summer of 1972, and the winter of 1972-73, the camp was used as a communications centre, and for providing other assistance to research stations established on Coburg Island and on the Carey Islands (Greenland) which are part of the Institute's North Water Project. ... [1] ECOLOGICAL STUDIES OF SEDGE-DOMINATED MEADOW TUNDRA. During the 1972 field season studies were continued on the ecology of sedge-dominated meadows. ... Studies of rhizome behaviour were continued. Complete systems were excavated and collected at five locations. Rhizome growth was monitored on selected individual plants. ... Population characteristics of sedges invading small ponds and drained lake systems were further investigated. Three-and-a-half weeks were spent at the National Museum of Natural History camp on Bathurst Island. ... six sedge meadows were selected and analysed for comparison with the Devon Island meadows. Five permanent plots were also established and mapped and populations of Carex stans collected for both seed and morphological measurements. A project to investigate the revegetation of vehicle-disturbed sedge meadows with native Carex species was also initiated. ... Analysis of plantings of Carex stans as well as natural revegetation in some blocks will be monitored in following seasons. ... [2] VEGETATION STUDIES ON THE INTERIOR PLATEAU. ... A 2.4 km transect was placed east from the Plateau margin to the interior. The transect crossed a number of habitats, including solifluction terraces, stripes and sorted nets. Four maximum-minimum thermometer enclosures and two hygrothermograph stations were set out to determine microclimatic variations along the line. Forty 25 m² quadrats were placed at 80 m intervals along the transect for vegetation analysis. At each plot, the percentage cover of rock, soil, vascular plants and bryophytes was calculated; species composition was determined and voucher specimens from each quadrat were collected. Lichen specimens were also collected for later taxonomic determinations in the laboratory. Surface soil samples from each plot were collected for mechanical and chemical analysis. ... At 5 points along the transect, regular sampling of soil at 0 and 15 cm was undertaken to determine a curve of seasonal soil moisture. These values will be compared with concurrent samples taken in nonsorted circles on the Lowland. In addition to the 40 systematic plots, 5 additional sites were also ana1ysed. ... Comparisons with the transect data should indicate if the visual homogeneity of the vegetation on the Plateau is constant over a large area. A high density bryophyte community at the head of a drainage system and one solifluction terrace characterized by Alopecurus were also analysed. These sites were unusual in that they both had vegetation cover values greater than 40 per cent. Other plots on the Plateau had values of 1 to 4 per cent. ..

The Effect of Dosage Release Formulations on the Pharmacokinetics of Propranolol Stereoisomers in Humans

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97148/1/j.1552-4604.1995.tb04076.x.pd

The Influence of Playing Position and Contextual Factors on Soccer Players’ Match Differential Ratings of Perceived Exertion::A Preliminary Investigation

(1) Background: Differential RPE (dRPE) separates scores for breathlessness (RPE-B), leg muscle exertion (RPE-L) and technical/cognitive exertion (RPE-T). Limited information for dRPE is available in soccer match play, yet these measurements may help inform practitioners training and recovery strategies. This preliminary study investigated the effects of playing position and contextual factors on elite soccer players’ dRPE. (2) Methods: Thirty-two male English Premier League players recorded dRPE scores 15–30 min post-match for RPE-B, RPE-L, and RPE-T. Data were analysed using linear mixed models, with magnitude-based inferences subsequently applied. (3) Results: Overall, the mean ± SD for the dRPE were 63 ± 23 arbitrary units (au) (RPE-B), 67 ± 22 au (RPE-L), and 60 ± 24 au (RPE-T). Full Backs reported substantially higher RPE-B, RPE-L and RPE-T when compared to all other positions. Substantially higher RPE-T scores were reported for matches played against Top teams compared to Bottom (10 au; 90% Confidence Interval 5 to 15 au) and Middle (10 au; 4 to 15 au) ranked teams. The effects of match result and location on dRPE were not substantial. (4) Conclusions: Positional differences were observed following soccer match play for RPE-B, RPE-L and RPE-T. Full backs had substantially higher dRPE then any other position, with all players reporting increased RPE-T when playing teams at the Top of the league. These findings can help practitioners monitor internal load responses and support the prescription of training and recovery sessions

Anti-self-dual conformal structures with null Killing vectors from projective structures

Using twistor methods, we explicitly construct all local forms of four--dimensional real analytic neutral signature anti--self--dual conformal structures $(M,[g])$ with a null conformal Killing vector. We show that $M$ is foliated by anti-self-dual null surfaces, and the two-dimensional leaf space inherits a natural projective structure. The twistor space of this projective structure is the quotient of the twistor space of $(M,[g])$ by the group action induced by the conformal Killing vector. We obtain a local classification which branches according to whether or not the conformal Killing vector is hyper-surface orthogonal in $(M, [g])$. We give examples of conformal classes which contain Ricci--flat metrics on compact complex surfaces and discuss other conformal classes with no Ricci--flat metrics.Comment: 43 pages, 4 figures. Theorem 2 has been improved: ASD metrics are given in terms of general projective structures without needing to choose special representatives of the projective connection. More examples (primary Kodaira surface, neutral Fefferman structure) have been included. Algebraic type of the Weyl tensor has been clarified. Final version, to appear in Commun Math Phy

Utah College Sexual Behavior Survey: Initial Findings Report

The purpose of the Utah College Sexual Behavior project was to establish the reliability and validity of the retrospective measures used in the survey and gain a better understanding of the sexual behaviors of Utah youth by asking Utah State University (USU) students about their sexual behaviors as youth

Does foraging efficiency vary with colony size in the fairy martin Petrochelidon ariel?

Colonial breeding occurs in a wide range of taxa, however the advantages promoting its evolution and maintenance remain poorly understood. In many avian species, breeding colonies vary by several orders of magnitude and one approach to investigating the evolution of coloniality has been to examine how potential costs and benefits vary with colony size. Several hypotheses predict that foraging efficiency may improve with colony size, through benefits associated with social foraging and information exchange. However, it is argued that competition for limited food resources will also increase with colony size, potentially reducing foraging success. Here we use a number of measures (brood feeding rates, chick condition and survival, and adult condition) to estimate foraging efficiency in the fairy martin Petrochelidon ariel, across a range of colony sizes in a single season (17 colonies, size range 28-139 pairs). Brood provisioning rates were collected from multiple colonies simultaneously using an electronic monitoring system, controlling for temporal variation in environmental conditions. Provisioning rate was correlated with nestling condition, though we found no clear relationship between provisioning rate and colony size for either male or female parents. However, chicks were generally in worse condition and broods more likely to fail or experience partial loss in larger colonies. Moreover, the average condition of adults declined with colony size. Overall, these findings suggest that foraging efficiency declines with colony size in fairy martins, supporting the increased competition hypothesis. However, other factors, such as an increased ectoparasitise load in large colonies or change in the composition of phenotypes with colony size may have also contributed to these patterns.

Socioeconomic factors that affect artisanal fishers’ readiness to exit a declining fishery

The emerging world crisis created by declining fish stocks poses a challenge to resource users and managers. The problem is particularly acute in poor nations, such as those in East Africa, where fishing is an important subsistence activity but high fishing intensity and use of destructive gear have resulted in declining catches. In this context developing effective management strategies requires an understanding of how fishers may respond to declines in catch. We examined the readiness of 141 Kenyan fishers to stop fishing under hypothetical scenarios of declines in catch and how socioeconomic conditions influenced their decisions. As expected, the proportion of fishers that would exit the fishery increased with magnitude of decline in catch. Fishers were more likely to say they would stop fishing if they were from households that had a higher material style of life and a greater number of occupations. Variables such as capital investment in the fishery and the proportion of catch sold had weak, nonsignificant relationships. Our finding that fishers from poorer households would be less likely to exit a severely declining fishery is consistent with the literature on poverty traps, which suggests the poor are unable to mobilize the necessary resources to overcome either shocks or chronic low-income situations and consequently may remain in poverty. This finding supports the proposition \ud that wealth generation and employment opportunities directed at the poorest fishers may help reduce fishing effort on overexploited fisheries, but successful interventions such as these will require an understanding of the socioeconomic context in which fishers operate. \u

Non-Abelian (p,q) Strings in the Warped Deformed Conifold

We calculate the tension of $(p,q)$-strings in the warped deformed conifold using the non-Abelian DBI action. In the large flux limit, we find exact agreement with the recent expression obtained by Firouzjahi, Leblond and Henry-Tye up to and including order $1/M^2$ terms if $q$ is also taken to be large. Furthermore using the finite $q$ prescription for the symmetrised trace operation we anticipate the most general expression for the tension valid for any $(p,q)$. We find that even in this instance, corrections to the tension scale as $1/M^2$ which is not consistent with simple Casimir scaling.Comment: 18 pages, Latex, 1 figure; Added a discussion of the case when the warp factor parameter $b\neq 1$ and typos correcte

Metabolomics guides rational development of a simplified cell culture medium for drug screening against <i>Trypanosoma brucei</i>

n vitro culture methods underpin many experimental approaches to biology and drug discovery. The modification of established cell culture methods to make them more biologically relevant or to optimize growth is traditionally a laborious task. Emerging metabolomic technology enables the rapid evaluation of intra- and extracellular metabolites and can be applied to the rational development of cell culture media. In this study, untargeted semiquantitative and targeted quantitative metabolomic analyses of fresh and spent media revealed the major nutritional requirements for the growth of bloodstream form &lt;i&gt;Trypanosoma brucei&lt;/i&gt;. The standard culture medium (HMI11) contained unnecessarily high concentrations of 32 nutrients that were subsequently removed to make the concentrations more closely resemble those normally found in blood. Our new medium, Creek's minimal medium (CMM), supports in vitro growth equivalent to that in HMI11 and causes no significant perturbation of metabolite levels for 94% of the detected metabolome (&#60;3-fold change; α = 0.05). Importantly, improved sensitivity was observed for drug activity studies in whole-cell phenotypic screenings and in the metabolomic mode of action assays. Four-hundred-fold 50% inhibitory concentration decreases were observed for pentamidine and methotrexate, suggesting inhibition of activity by nutrients present in HMI11. CMM is suitable for routine cell culture and offers important advantages for metabolomic studies and drug activity screening