Occurrence of Arctic Cod (Boreogadus saida) Schools and Their Vulnerability to Predation in the Canadian High Arctic

We document the occurrence of large schools of Arctic cod (Boreogadus saida) in the Barrow Strait region of the eastern Canadian Arctic during the open water season. Schools were most frequently observed near shore, often in depressions inside bays. Schools ranged up to 130 000 sq m surface area and contained on the order of 4 x 10**8 fish, weighing 12 000 tonnes. Evidence indicates that schools form before the arrival of predators, but when they occur in shallow water, they are often subjected to intense predation by thousands of seabirds and marine mammals, primarily black-legged kittiwakes (Rissa tridactyla), northern fulmars (Fulmarus glacialis), harp seals (Phoca groenlandicus), beluga (Delphinapterus leucas) and narwhal (Monodon monoceros). The reasons for such schooling behaviour are unknown.On étudie la présence de grands bancs de morue arctique (Boreogadus saida) dans la région du détroit de Barrow située dans l'Arctique canadien oriental durant la saison d'eau libre. On a observé que les bancs se tenaient le plus fréquemment près du rivage, souvent dans des dépressions à l'intérieur des baies. Les bancs couvraient jusqu'à 130 000 m² et comptaient en gros 4 x 10**8 poissons, pour un poids total de 12 000 tonnes. L'étude révèle que les bancs se constituent avant l'arrivée des prédateurs, mais lorsqu'ils se trouvent dans des eaux peu profondes, ils sont souvent la proie de milliers d'oiseaux et mammifères marins voraces, en particulier la mouette tridactyle (Rissa tridactyla), le fulmar boréal (Fulmarus glacialis), le phoque du Groenland (Phoca groenlandicus), le béluga (Delphinapterus leucas), et le narval (Monodon monoceros). On ne connaît pas les causes du regroupement des poissons en bancs

Kvantitativna analiza tragova manganovih iona korištenjem voltametrijske redukcije manganova dioksida akumuliranog na površini radne elektrode: ispitivanje svojstava grafitne elektrode s radnom površinom okomitom na slojeve grafita i mogućnosti njene primjene u analizi prirodnih voda

The determination of trace levels of manganese via cathodic stripping voltammetry at an edge plane pyrolytic graphite electrode (eppge) was evaluated for use in environmental analysis. The response of the eppge is compared with boron-doped diamond electrodes under quiescent conditions where the former is observed to have a three times higher sensitivity. Using this protocol with a stirred accumulation period, a detection limit of 14.2 nmol dm–3 and a sensitivity of 14.2 mol dm–3 A–1 is achieved with linearity from 25 to 250 nmol dm–3, based on a 120 seconds accumulation period. The response at a carbon paste electrode is also compared under the same conditions with the eppge found to be superior in terms of sensitivity, detection limits and reproducibility. The efficacy of the protocol utilising the eppge was assessed in the determination of manganese in a certified seawater reference material, NASS-5, from the National Research Council Canada, which was found to be in excellent agreement with the independently verified sample.Istražena je mogućnost određivanja koncentracije manganovih iona u prirodnim vodama korištenjem grafitne elektrode s radnom površinom okomitom na slojeve grafita u kombinaciji s voltametrijskom metodom koja se zasniva na redukciji manganova dioksida akumuliranog na površini radne elektrode. Ako se MnO2 akumulira iz mirne otopine, osjetljivost grafitne elektrode je tri puta veća od osjetljivosti dijamantne elektrode dopirane borom. Kada se akumulacija provodi tokom 120 sekundi uz miješanje otopine, osjetljivost metode je 14,2 mol dm–3 A–1, granica detekcije mangana je 14,2 nmol dm–3, a odziv je linearna funkcija koncentracije mangana u rasponu od 25 do 250 nmol dm–3. Grafitna elektroda osjetljivija je i pouzdanija i od elektrode sačinjene od žitke smjese čađi i mineralnog ulja. Točnost metode potvrđena je mjerenjem koncentracije manganovih iona u referentnom uzorku morske vode (NASS-5, Nacionalni istraživački savjet Kanade)

Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System

Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations, while meeting crew and vehicle safety requirements. The analyses and associated testing presented here surround a second generation of the airbag design developed by ILC Dover, building off of relevant first-generation design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley s Landing and Impact Research (LandIR) facility in Hampton, Virginia. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, develop the simulations, and make comparisons to experimental data are discussed

High variability of food and nutrient intake exists across the Mediterranean Dietary Pattern- a systematic review

A Mediterranean style dietary pattern (MDP) is considered beneficial for health. The MD Score (MDS) definition has evolved, resulting in considerable variability in the foods and nutrients associated with MDS adherence. We systematically investigated food and nutrient composition of the MD between studies, countries, and methods of classifying the MDS. We searched Embase for MD systematic reviews and selected observational studies reporting intakes of foods, macronutrients, or micronutrients by categories of MDS adherence. The percentage differences in food and nutrient intakes between categories of high and low adherence to the MDS were calculated for each study. A total of 369 full-text primary papers were reviewed from the included systematic reviews and 74 papers selected (66 adults, 8 children). We found considerable differences in MDS definitions and scoring criteria. Between-study variation in food intake between high- and low-adherence MDS adherence categories ranged from a mean of −23% for meat, to 119% for fruit, and 278% for fish. Greater variability was evident in non-Mediterranean than Mediterranean regions. We conclude that few studies report food and nutrient intakes across the range of the MDP in adults and even fewer in children. The considerable variability in the foods and nutrients reported makes comparison of results from studies and translation into dietary guidelines difficult. We recommend that future publications of MD studies include full details of the range of food and nutrient intakes across the distribution of MD adherence in order to facilitate translation into health policy and practice

STS-74/Mir Photogrammetric Appendage Structural Dynamics Experiment Preliminary Data Analysis

The Photogrammetric Appendage Structural Dynamics Experiment was designed, developed, and flown to demonstrate and prove measurement of the structural vibration response of a Russian Space Station Mir solar array using photogrammetric methods. The experiment flew on the STS-74 Space Shuttle mission to Mir in November 1995 and obtained video imagery of solar array structural response to various excitation events. The video imagery has been digitized and triangulated to obtain response time history data at discrete points on the solar array. This data has been further processed using the Eigensystem Realization Algorithm modal identification technique to determine the natural vibration frequencies, damping, and mode shapes of the solar array. The results demonstrate that photogrammetric measurement of articulating, non-optically targeted, flexible solar arrays and appendages is a viable, low-cost measurement option for the International Space Station

Localized Tensional Forces on PECAM-1 Elicit a Global Mechanotransduction Response via the Integrin-RhoA Pathway

SummaryBackgroundMechanical forces regulate cell behavior and function during development, differentiation, and tissue morphogenesis. In the vascular system, forces produced by blood flow are critical determinants not only of morphogenesis and function, but also of pathological states such as atherosclerosis. Endothelial cells (ECs) have numerous mechanotransducers, including platelet endothelial cell adhesion molecule-1 (PECAM-1) at cell-cell junctions and integrins at cell-matrix adhesions. However, the processes by which forces are transduced to biochemical signals and subsequently translated into downstream effects are poorly understood.ResultsHere, we examine mechanochemical signaling in response to direct force application on PECAM-1. We demonstrate that localized tensional forces on PECAM-1 result in, surprisingly, global signaling responses. Specifically, force-dependent activation of phosphatidylinositol 3-kinase (PI3K) downstream of PECAM-1 promotes cell-wide activation of integrins and the small GTPase RhoA. These signaling events facilitate changes in cytoskeletal architecture, including growth of focal adhesions and adaptive cytoskeletal stiffening.ConclusionsTaken together, our work provides the first evidence of a global signaling event in response to a localized mechanical stress. In addition, these data provide a possible mechanism for the differential stiffness of vessels exposed to distinct hemodynamic force patterns in vivo

Energy Flow through the Marine Ecosystem of the Lancaster Sound Region, Arctic Canada

This paper synthesizes the trophic dynamics of a Canadian arctic marine ecosystem in so far as it is known, using new data on primary production, zooplankton, the bivalve Mya truncata, and arctic cod (Boreogadus saida), as well as literature values for marine mammals and seabirds. The 98,000 sq km region has a high rate of primary production relative to other parts of arctic Canada. About 60 g C/sq. m are fixed annually, of which approximately 90% is contributed by phytoplankton, 10% by ice algae, and 1% by kelp. Phytoplankton production is twofold higher along the south coast of Cornwallis Island than elsewhere in Barrow Strait. Four copepod species, of which Pseudocalanus acuspes is the most important energetically, graze about one-third of the phytoplankton production. Bivalves maintain high biomass but low energy flow, acting as sedimenting agents. Arctic cod is a major component, with 125,000 tonnes being consumed by marine mammals and 23,000 tonnes by seabirds annually. Our hydro-acoustic estimate for mean arctic cod density, 0.0022 fish/sq. m, is probably too low, partly because we have been unable to quantify dense aggregations of schooling fish. The ecological efficiency of ringed seal is near maximum, with 5% of ringed seal ingestion going to bears and man as seal flesh. The data on total kill and prey consumption in whales and birds is incomplete because they migrate out of the Lancaster Sound region in winter. The food chain is very long, with bears occupying the fifth trophic level; this is reflected by high biomagnification factors for persistent lipophilic pollutants such as PCBs. There are major data gaps for some zooplankton and most of the benthos, as well as for winter populations and energetics. This trophic analysis is therefore incomplete and efficiencies for entire trophic levels cannot be calculated.Key words: seals, whales, seabirds, benthos, zooplankton, phytoplankton, primary production, secondary production, harvest, yieldRÉSUMÉ. Cet article résume la dynamique trophique de l’écosystème marin dans le Canada arctique dans la mesure où il est connu, en utilisant de nouvelles données sur la production primaire, le zooplancton, le bivalve Mya truncata, et la morue polaire (Boreogadus saida), ainsi que les valeurs trouvées dans la documentation sur les mammifères et les oiseaux marins. Cette région d’une superficie de 98 000 km2 possède un taux élevé de production primaire par rapport à d’autres parties du Canada arctique. Environ 60 g C.m-2 sont fixés annuellement, dont environ 90 p. cent par le phytoplancton, 10 p. cent par les algues glaciaires et 1 p. cent par les laminaires. La production de phytoplancton est deux fois plus élevée le long de la côte méridionale de l’île Cornwallis qu’ailleurs dans le détroit de Barrow. Quatre espèces de copépodes, dont la Pseudocalanus acuspes est la plus importante du point de vue énergitique, utilisent environ un tiers de la production de phytoplancton pour se nourir. Les bivalves contribuent de façonimportante à la biomasse mais peu au flux énergétique, étant des agents de sédimentation. La morue arctique est une composante importante, étant consommée au taux annuel de 1250 00 tonnes par les mammifères marins et de 23 000 tonnes par les oiseaux marins. Notre estimation hydroacoustique pour la densité moyenne de la morue arctique, 0,002 poissons.m-2, est probablement trop faible, en partie parce que nous avons été incapables de quantifier les regroupements denses des poissons se rassemblant en bancs. L’efficacité écologique du phoque annelé est proche de son maximum, 5 p. cent de l’ingestion de cet animal allant à l’ours et à l’homme sous forme de chair de phoque. Les données sur le nombre d’animaux tués et sur laconsommation de proies chez les baleines et les oiseaux sont incomplètes en raison de leur migration hivernal à  l'extérieur du détroit de Lancaster. La chaine alimentaire est très longue, les ours occupant le cinquième niveau trophique; cela se traduit par des facteurs de bioamplification élevés en ce qui concerne les polluants lipophiles persistants tels que les BPC. Il existe des lacunes dans les données pour certains éléments du zooplancton et pour la plupart du benthos, ainsi que pour les populations et l’énergétique hivernales. Cette analyse trophique est donc incomplète et il n'est pas possible de calculer l’efficacité pour l’ensemble des niveaux trophiques.Mots clés: phoques, baleines, oiseaux marins, benthos, zooplancton, phytoplancton, production primaire, production secondaire, prélèvement, rendemen

1976: Abilene Christian College Bible Lectures - Full Text

FREEDOM IN CHRIST Being the Abilene Christian College Annual Bible Lectures 1976 Published by ABILENE CHRISTIAN COLLEGE Book Store ACC Station Abilene, Texas 7960