2,254 research outputs found

    Density Distribution of Fish in the Presence of Whales at the Admiralty Inlet Landfast Ice Edge

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    Hydroacoustic techniques were used to search for fish beneath landfast sea ice in Admiralty Inlet, Northwest Territories, Canada, when narwhal (Monodon monoceros) and beluga whales (Delphinapterus leucas) were congregating at the ice edge in the mouth of the inlet. Fish, presumably Arctic cod (Boreogadus saida), were distributed in the water column within four general layers or zones; near the ice undersurface, about 40 m deep, about 80-100 m deep, and about 150-200 m deep. The distribution of the first three layers roughly corresponded with the distribution of larger zooplankters, also estimated hydroacoustically. We recorded higher densities immediately below the ice than farther down in the water column. Maximum density in both regions occurred about 10 km from the ice edge. Fish density was low in the immediate vicinity of the ice edge. The distribution of fish underneath the landfast ice of Admiralty Inlet is postulated to have been influenced by the distribution of zooplankton, their principle food source, rather than by the presence of whales.

    Assessment of Connections Between Knowledge- Based Economy Characteristics and Selected Macroeconomic Categories in the European Union's Countries by Means of Panel Models

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    The aim of the article is to analyze the impact of knowledge-based economy variables on the selected macroeconomic categories - the share of total investments in GDP and the employment rate- in European Union's countries in the years 2000-2007, conducted with application of panel models.Celem artykułu jest analiza wpływu zmiennych opisujących gospodarkę opartą na wiedzy na podstawowe kategorie makroekonomiczne - udział całkowitych inwestycji w PKB i stopę zatrudnienia - w krajach Unii Europejskiej (z podziałem na kraje UE-15 i nowe kraje członkowskie UE) w latach 2000-2007, przeprowadzona w oparciu o modele panelowe

    On the appearance of Eisenstein series through degeneration

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    Let Γ\Gamma be a Fuchsian group of the first kind acting on the hyperbolic upper half plane H\mathbb H, and let M=Γ\HM = \Gamma \backslash \mathbb H be the associated finite volume hyperbolic Riemann surface. If γ\gamma is parabolic, there is an associated (parabolic) Eisenstein series, which, by now, is a classical part of mathematical literature. If γ\gamma is hyperbolic, then, following ideas due to Kudla-Millson, there is a corresponding hyperbolic Eisenstein series. In this article, we study the limiting behavior of parabolic and hyperbolic Eisenstein series on a degenerating family of finite volume hyperbolic Riemann surfaces. In particular, we prove the following result. If γΓ\gamma \in \Gamma corresponds to a degenerating hyperbolic element, then a multiple of the associated hyperbolic Eisenstein series converges to parabolic Eisenstein series on the limit surface.Comment: 15 pages, 2 figures. This paper has been accepted for publication in Commentarii Mathematici Helvetic

    Ecological Footprint Model Using the Support Vector Machine Technique

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    The per capita ecological footprint (EF) is one of the most widely recognized measures of environmental sustainability. It aims to quantify the Earth's biological resources required to support human activity. In this paper, we summarize relevant previous literature, and present five factors that influence per capita EF. These factors are: National gross domestic product (GDP), urbanization (independent of economic development), distribution of income (measured by the Gini coefficient), export dependence (measured by the percentage of exports to total GDP), and service intensity (measured by the percentage of service to total GDP). A new ecological footprint model based on a support vector machine (SVM), which is a machine-learning method based on the structural risk minimization principle from statistical learning theory was conducted to calculate the per capita EF of 24 nations using data from 123 nations. The calculation accuracy was measured by average absolute error and average relative error. They were 0.004883 and 0.351078% respectively. Our results demonstrate that the EF model based on SVM has good calculation performance

    The UCSD Radio-Selected Quasar Survey for Damped Lyman alpha System

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    As large optical quasar surveys for damped Lya become a reality and the study of star forming gas in the early Universe achieves statistical robustness, it is now vital to identify and quantify the sources of systematic error. Because the nature of optically-selected quasar surveys makes them vulnerable to dust obscuration, we have undertaken a radio-selected quasar survey for damped Lya systems to address this bias. We present the definition and results of this survey. We then combine our sample with the CORALS dataset to investigate the HI column density distribution function f(N) of damped Lya systems toward radio-selected quasars. We find that f(N) is well fit by a power-law f(N) = k_1 N^alpha_1, with log k_1 = 22.90 and alpha_1 = -2.18. This power-law is in excellent agreement with that of optically-selected samples at low N(HI), an important yet expected result given that obscuration should have negligible effect at these gas columns. However, because of the relatively small size of the radio-selected sample, 26 damped Lya systems in 119 quasars, f(N) is not well constrained at large N(HI) and the first moment of the HI distribution function, Omega_g, is, strictly speaking, a lower limit. The power-law is steep enough, however, that extrapolating it to higher column densities implies only a modest, logarithmic increase in Omega_g. The radio-selected value of Omega_g = 1.15 x 10^-3, agrees well with the results of optically-selected surveys. While our results indicate that dust obscuration is likely not a major issue for surveys of damped Lya systems, we estimate that a radio-selected sample of approximately 100 damped Lya systems will be required to obtain the precision necessary to absolutely confirm an absence of dust bias.Comment: 12 pages, 9 Figures. Accepted to ApJ April 11, 200

    On the possible induced charge on a graphitic nanocone at finite temperature

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    Electronic excitations in a graphitic monolayer (graphene) in the long-wavelength approximation are characterized by the linear dispersion law, representing a unique example of the really two-dimensional "ultrarelativistic" fermionic system which in the presence of topological defects possesses rather unusual properties. A disclination that rolls up a graphitic sheet into a nanocone is described by a pointlike pseudomagnetic vortex at the apex of the cone, and the flux of the vortex is related to the deficit angle of the conical surface. A general theory of planar relativistic fermionic systems in the singular vortex background is employed, and we derive the analytical expression for the charge which is induced at finite temperature on some graphitic nanocones.Comment: 8 pages, minor changes, journal version (based on a talk given on QFEXT07, Leipzig, 2007

    The impact of telecommunication technologies on competition in services and goods markets: Empirical evidence

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    In this paper we empirically show that a more intensive use and wider adoption of telecommunication technologies significantly increases the level of product market competition in services and goods markets. Our results are consistent with the view that the use of telecommunication technologies can lower the costs of entry and search. These findings are robust to various measures of competition and a wide range of specification checks

    996-11 Direct Gene Transfer and Expression with Arterial Iontophoretic Catheter Delivery

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    Iontophoresis is a technique of molecular delivery which uses electric current to enhance movement of charged molecules into tissues. A porous balloon catheter was tested with a central silver chloride electrode capable of generating a potential gradient across the arterial wall using an adhesive patch placed on the skin to serve as the anode. We hypothesized that this catheter delivery system might effectively transfer negatively charged plasmid DNA into arterial cells in vivo.MethodsTo localize plasmid DNA arterial delivery, a 7 Fr iontophoretic porous balloon catheterwast,’aced into porcine carotid arteries underflouroscopic guidance. 15μg of 35S-Iabeled plasmid DNA (1.4×106 cpm/μg) expressing the heat stable human alkaline phosphatase (hAP) gene with an RSV promoter was infused through the balloon at 6 atm pressure. A constant current density of 2.5 mA/cm2 was maintained for 10 minutes. The ;35S-labeled plasmid DNA delivery was repeated on the contralateral carotid artery under identical conditions with the absence of electric current. 20 minutes after gene transfer, the arteries were fixed in situ and processed for autoradiography. To analyze gene transfer and expression, 8 porcine carotid arterial segments were subject to iontophoretic gene delivery for 10 minutes at 6 atm with a current density of 2.5 mA/cm2 using the RSV hAP plasmid (n=6) or control plasmid (n=2). Animals were sacrificed 5 days after gene delivery and the transfected arteries analyzed by PCR and heat stable alkaline phosphatase histochemistry.ResultsAutoradiography of the arteries which underwent ;35S-labeled plasmid delivery revealed minimal radiolabel in the luminal cells of the control artery in which current was not delivered. In contrast, significant amounts of radiolabel were present in the media and adventitia of the artery subject to current delivery. PCR analysis of the arterial segments studied 5 days after delivery confirmed gene transfer in all hAP segments and was negative in control arteries. Staining for heat stable recombinant alkaline phosphatase activity demonstrated recombinant protein expression in 5% of medial cells and 10% of adventitial cells in arteries which underwent hAP gene transfer. Control arteries were negative for hAP staining.ConclusionsIontophoretic catheter gone delivery can be used to perform direct plasmid DNA delivery with expression of recombinant protein in medial and adventitial cells
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