2,503 research outputs found

    Mercury, Water, PCB, DDT

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    Beluga whales living in the St. Lawrence River estuary are so contaminated with toxins that their bodies, when they wash ashore, are treated as toxic waste. They are exposed to industrial pollution from the Great Lakes region, which empties into the St. Lawrence. Using chemical formulas and symbols for mercury, PCB, DDT, and water allowed me to depict the primary toxins found directly in this animal’s watery habitat. These chemical structures render scientific information and knowledge visible, which highlights the impact that we, as a species, have in the environment and the lives of other animals...Find full piece in .pdf below

    Analysis of Daily Air Temperatures across a Topographically Complex Alpine Region of Southwestern Yukon, Canada

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    This study provides an analysis of six years of daily air temperature data collected using 16 HOBOÂź UA-002-64 Pendant data loggers placed along a 280 km transect in southwestern Yukon and northern British Columbia. Correlation and time series analyses, including Seasonal Decomposition of Time Series by Loess (STL) methods, revealed very high correlations among all data series at daily to annual timescales. The two meteorological stations in the region are found to be generally representative of the greater area, and local temperature variability appears to be predominantly determined by synoptic-scale weather patterns. The annual temperature cycle in this region is complex and has annually repeating components at all study sites across the region. The analysis of daily data using the STL method can provide new insight into climate time series and enhance our ability to observe patterns and extremes in temperatures across varying spatial and temporal scales. Data loggers provide a cost-effective way of obtaining similar (and sometimes higher-quality) information compared to meteorological stations or gridded global datasets.Cette Ă©tude prĂ©sente l’analyse de donnĂ©es sur la tempĂ©rature de l’air prĂ©levĂ©es au cours de six annĂ©es Ă  l’aide de 16 enregistreurs de donnĂ©es HOBOMD UA-002-64 Pendant le long d’un transect de 280 km situĂ© dans le sud-ouest du Yukon et le nord de la Colombie-Britannique. L’analyse des corrĂ©lations et des sĂ©ries temporelles, faisant notamment appel aux mĂ©thodes de dĂ©composition saisonniĂšre des sĂ©ries temporelles de Loess (STL), ont rĂ©vĂ©lĂ© de trĂšs fortes corrĂ©lations entre toutes les sĂ©ries de donnĂ©es aux Ă©chelles de temps allant de quotidiennes Ă  annuelles. Les deux stations mĂ©tĂ©orologiques de la rĂ©gion sont gĂ©nĂ©ralement reprĂ©sentatives de la grande rĂ©gion, et la variabilitĂ© des tempĂ©ratures locales semble principalement dĂ©terminĂ©e par le rĂ©gime climatique Ă  l’échelle synoptique. Dans cette rĂ©gion, le cycle des tempĂ©ratures annuelles est complexe. Il comprend des composantes rĂ©currentes annuellement Ă  tous les sites Ă©tudiĂ©s, Ă  la grandeur de la rĂ©gion. L’analyse des donnĂ©es quotidiennes Ă  l’aide de la mĂ©thode STL peut donner une nouvelle perspective des sĂ©ries temporelles climatiques et rehausser notre capacitĂ© Ă  observer les tendances et les extrĂȘmes de tempĂ©ratures pour des Ă©chelles spatiales et temporelles variĂ©es. Les enregistreurs de donnĂ©es constituent une maniĂšre Ă©conomique d’obtenir des renseignements similaires (et parfois de meilleure qualitĂ©), comparativement aux donnĂ©es des stations mĂ©tĂ©orologiques ou aux ensembles de donnĂ©es globales sous forme de valeurs aux points de grille

    Application of Leg, Vertical, and Joint Stiffness in Running Performance: A Literature Overview

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    Stiffness, the resistance to deformation due to force, has been used to model the way in which the lower body responds to landing during cyclic motions such as running and jumping. Vertical, leg, and joint stiffness provide a useful model for investigating the store and release of potential elastic energy via the musculotendinous unit in the stretch-shortening cycle and may provide insight into sport performance. This review is aimed at assessing the effect of vertical, leg, and joint stiffness on running performance as such an investigation may provide greater insight into performance during this common form of locomotion. PubMed and SPORTDiscus databases were searched resulting in 92 publications on vertical, leg, and joint stiffness and running performance. Vertical stiffness increases with running velocity and stride frequency. Higher vertical stiffness differentiated elite runners from lower-performing athletes and was also associated with a lower oxygen cost. In contrast, leg stiffness remains relatively constant with increasing velocity and is not strongly related to the aerobic demand and fatigue. Hip and knee joint stiffness are reported to increase with velocity, and a lower ankle and higher knee joint stiffness are linked to a lower oxygen cost of running; however, no relationship with performance has yet been investigated. Theoretically, there is a desired “leg-spring” stiffness value at which potential elastic energy return is maximised and this is specific to the individual. It appears that higher “leg-spring” stiffness is desirable for running performance; however, more research is needed to investigate the relationship of all three lower limb joint springs as the hip joint is often neglected. There is still no clear answer how training could affect mechanical stiffness during running. Studies including muscle activation and separate analyses of local tissues (tendons) are needed to investigate mechanical stiffness as a global variable associated with sports performance

    The Levantine Basin - crustal structure and origin

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    The origin of the Levantine Basin in the Southeastern Mediterranean Sea is related to the opening of the Neo-Tethys. The nature of its crust has been debated for decades. Therefore, we conducted a geophysical experiment in the Levantine Basin. We recorded two refraction seismic lines with 19 and 20 ocean bottom hydrophones, respectively, and developed velocity models. Additional seismic reflection data yield structural information about the upper layers in the first few kilometers. The crystalline basement in the Levantine Basin consists of two layers with a P-wave velocity of 6.06.4 km/s in the upper and 6.56.9 km/s in the lower crust. Towards the center of the basin, the Moho depth decreases from 27 to 22 km. Local variations of the velocity gradient can be attributed to previously postulated shear zones like the Pelusium Line, the DamiettaLatakia Line and the BaltimHecateus Line. Both layers of the crystalline crust are continuous and no indication for a transition from continental to oceanic crust is observed. These results are confirmed by gravity data. Comparison with other seismic refraction studies in prolongation of our profiles under Israel and Jordan and in the Mediterranean Sea near Greece and Sardinia reveal similarities between the crust in the Levantine Basin and thinned continental crust, which is found in that region. The presence of thinned continental crust under the Levantine Basin is therefore suggested. A β-factor of 2.33 is estimated. Based on these findings, we conclude that sea-floor spreading in the Eastern Mediterranean Sea only occurred north of the Eratosthenes Seamount, and the oceanic crust was later subducted at the Cyprus Arc

    The finite dimensional attractor for a 4th order system of Cahn-Hilliard type with a supercritical nonlinearity

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    This article is devoted to the study of the long-time behavior of solutions of the following 4th order parabolic system in a bounded smooth domain Ω ⊂⊂ ℝn: b∂t u = -ÎŽx (aÎŽxu - a∂tu - f(u) + g̃), (1) where u = (u1,., uk) is an unknown vector-valued function, a and b are given constant matrices such that a + a* > 0, b = b* > 0, α > 0 is a positive number, and f and g are given functions. Note that the nonlinearity f is not assumed to be subordinated to the Laplacian. The existence of a finite dimensional global attractor for system (1) is proved under some natural assumptions on the nonlinear term f

    DETERMINANTS OF THE MAXIMAL MECHANICAL POWER DEVELOPED DURING THE COUNTERMOVEMENT JUMP (CMJ)

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    INTRODUCTION A countermovement (a preparatory movement in the direction opposite to that of the goal) increases performance in explosive movements such as the CMJ. The height of jump and the maximal power relative to body weight have been reported to be significantly correlated. Our previous observations has suggested the take-off technique (the countermovement depth) to affect power rather than height of jump. The purpose of the present study was to determine the influence of the height of jump, of the countermovement depth and of body mass on the maximal mechanical power developed during the positive take-off phase. METHODS Untrained students (56 female and 38 male) volunteered to take part in the CMJ jumping test consisting of 3 jumps performed with one-minute intervals on the computerized Kistler force plate. The subjects were requested to jump on the maximal height possible. Results of the highest jump were selected for each subject for further processing. The following variables were included into statistical analysis: the maximal mechanical power (PmaJ developed during the take-off, the height of jump (H), lowering of the body mass center before the take-off (L). and body mass (mb)' The Shapiro-Wilk test was used to examine the distributions of the tested variables. Pearson's correlation matrix and multiple regression analysis were employed to identity the parameters of the Pmax statistical model. Dolittle's method was used to estimate the contribution of the selected jump variables to the Pmax. RESULTS In both female and male groups the multiple regression procedure (the forward stepwise method) employed all the independent variables studied to construct the regressions equations. both of them proving very highly significant (

    Late Holocene Pollen Stratigraphy in Four Northeastern United States Lakes

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    Four pollen diagrams from Maine, New York, and Pennsylvania provide fine resolution (40 or 80 years) records of vegetation change in northeastern United States during the past 2000 years. A long term increase in pollen accumulation rates (PAR) of Picea occurred at the three sites in Maine and New York. Around 1100 years ago, Tsuga and Fagus decreased and Quercus and Castanea increased at Ely Lake in northeastern Pennsylvania. Around 500 years ago, Tsuga and Fagus greatly decreased in Maine and northern New York, while in northeastern Pennsylvania there was an increase in Tsuga and Fagus and a decrease in Quercus and Castanea pollen. Non-arboreal PAR were negligible prior to the European settlement of the area, after which there was an abrupt increase in non-arboreal pollen types.Quatre diagrammes polliniques des Ă©tats du Maine, de New York et de Pennsylvanie illustrent de maniĂšre dĂ©taillĂ©e (40 ou 80 ans) les changements survenus dans la vĂ©gĂ©tation du nord-est des États-Unis sur une pĂ©riode de 2000 ans. Les trois diagrammes des Ă©tats du Maine et de New York enregistrent un accroissement continu de l'influx pollinique (PAR) de Picea. Il y a environ 1100 ans, Tsuga et Fagus ont subi une diminution, tandis que Quercus et Castanea ont augmentĂ© Ă  Ely Lake, dans le nord-est de la Pennsylvanie. Il y a 500 ans, Tsuga et Fagus ont considĂ©rablement diminuĂ© dans les Ă©tats du Maine et de New York, alors que leur reprĂ©sentation pollinique augmentait dans le nord-est de la Pennsylvanie et que Quercus et Castanea diminuaient. Les influx polliniques des herbacĂ©s Ă©taient minimes avant l'arrivĂ©e des EuropĂ©ens dans la rĂ©gion, aprĂšs quoi ces taxons ont connu une augmentation subite.Vier Pollen-Diagramme von Maine, New York und Pennsylvania geben detaillierte AuflĂŽsungs-Nachweise der Vegetationswechsel im Nordosten der Vereinigten Staaten wĂ hrend der letzten 2000 Jahre. Ein langfristiges Anwachsen der Pollen-Akkumulationsraten (PAR) von Picea trat an den drei Fundstellen in Maine und im Staat New York auf. Vor ungefĂ hr 11000 Jahren, nahmen am Ely-See in Nordost-Pennsylvania Tsuga and Fagus ab und Quercus und Castanea zu. Vor ungefĂ hr 500 Jahren nahmen in Maine und im Norden des staats New York Tsuga und Fagus stark ab, wĂ hrend in Nordost-Pennsylvania Tsuga und Fagus zunahmen und Quercus und Casfanea-Pollen abnahmen. Die nicht von BĂ umen stammenden PAR waren gering, bevor das Gebiet von EuropĂ ern besiedelt wurde, wĂ hrend danach die nicht von BĂ umen stammenden Pollenarten plĂŽtzlich anwuchsen
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