2,627 research outputs found

    An Optical Scalar Approach to Weak Gravitation Lensing

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    We assume a thick gravitational lens governed by a Baltz n=1 matter density model. From the gravitational potential we then derive expressions for a Weyl tensor component and Ricci tensor component. A perturbative approach is taken to solve for the convergence and shear as given by Sach’s equation. By applying the geodesic deviation equation to a bundle of light rays with our expressions for the optical scalars we are able to derive expressions for the image shape and size at any point along the path from source to observer, in the case of an axially symmetric lens and source

    Synthesizing and Characterizing Sr\u3csub\u3e2\u3c/sub\u3eFeMoO\u3csub\u3e6\u3c/sub\u3e Bulk and Thin Films

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    A Sr2FeMoO6 (SFMO) pellet was synthesized to use as a target in the Pulsed Laser Deposition (PLD) chamber. The method chosen was a solid state reaction of SrCO3, Fe2O3 and MoO3. All three materials were combined stoichiometrically, ground in a ball mixer, and annealed for 36 hours at 1000°C. A pellet press was custom designed and used to press the annealed powders into a pellet. The magnetic and structural properties of the powder were studied using a Quantum Design MPMS SQUID magnetometer and powder X-Ray diffractometer, respectively. Previous studies of bulk SFMO suggest it to be ferrimagnetic or ferromagnetic, with a magnetic ordering near 400K. The magnetization data completely agrees with the reported data. The 1” diameter pellet was used as a target in the PLD chamber to grow a 200 nm thin film on a SrTiO3 (001) substrate at 800°C and 10-6 torr. X-Ray diffraction was performed on the film to ensure it was epitaxially oriented. From this data, calculations were performed which found the thin film to have been grown epitaxially

    Investigação da ligação do cobre às proteínas hidrossolúveis de um anfípodo

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    This study investigated the body copper accumulation in the amphipod Gammarus sp.. Groups of copper-binding proteins were also investigated considering their molecular weights. Regarding copper accumulation, a saturation type kinetics was observed with Km and Vmax values of 0.48 mg Cu.L–1 and 713.3 μg Cu.g–1 dw, respectively. Size exclusion chromatography (5 to 150 KDa) associated with ICP-MS showed that most of copper-binding proteins in Gammarus sp. have molecular weights <12 KDa, probably corresponding to metallothioneins.Este estudo investigou a acumulação corporal do cobre no anfípodo Gammarus sp.. Grupos de proteínas ligadas ao cobre foram também investigadas considerando seu peso molecular. Em relação à acumulação de cobre, foi observada uma sinética do tipo saturação com valores de Km e Vmax de 0,48 mg Cu.L–1 e 713,3 μg Cu.g–1 ps, respectivamente. A cromatografia de exclusão por tamanho (5 a 150 KDa) associada ao ICP-MS, mostrou que a maioria das proteínas ligadas ao cobre em Gammarus sp. têm peso molecular <12 KDa, provavelmente correspondendo às metalotioneínas

    Investigação da ligação do cobre às proteínas hidrossolúveis de um anfípodo

    Get PDF
    This study investigated the body copper accumulation in the amphipod Gammarus sp.. Groups of copper-binding proteins were also investigated considering their molecular weights. Regarding copper accumulation, a saturation type kinetics was observed with Km and Vmax values of 0.48 mg Cu.L–1 and 713.3 μg Cu.g–1 dw, respectively. Size exclusion chromatography (5 to 150 KDa) associated with ICP-MS showed that most of copper-binding proteins in Gammarus sp. have molecular weights <12 KDa, probably corresponding to metallothioneins.Este estudo investigou a acumulação corporal do cobre no anfípodo Gammarus sp.. Grupos de proteínas ligadas ao cobre foram também investigadas considerando seu peso molecular. Em relação à acumulação de cobre, foi observada uma sinética do tipo saturação com valores de Km e Vmax de 0,48 mg Cu.L–1 e 713,3 μg Cu.g–1 ps, respectivamente. A cromatografia de exclusão por tamanho (5 a 150 KDa) associada ao ICP-MS, mostrou que a maioria das proteínas ligadas ao cobre em Gammarus sp. Têm peso molecular <12 KDa, provavelmente correspondendo às metalotioneínas

    Continuous image distortion by astrophysical thick lenses

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    Image distortion due to weak gravitational lensing is examined using a non-perturbative method of integrating the geodesic deviation and optical scalar equations along the null geodesics connecting the observer to a distant source. The method we develop continuously changes the shape of the pencil of rays from the source to the observer with no reference to lens planes in astrophysically relevant scenarios. We compare the projected area and the ratio of semi-major to semi-minor axes of the observed elliptical image shape for circular sources from the continuous, thick-lens method with the commonly assumed thin-lens approximation. We find that for truncated singular isothermal sphere and NFW models of realistic galaxy clusters, the commonly used thin-lens approximation is accurate to better than 1 part in 10^4 in predicting the image area and axes ratios. For asymmetric thick lenses consisting of two massive clusters separated along the line of sight in redshift up to \Delta z = 0.2, we find that modeling the image distortion as two clusters in a single lens plane does not produce relative errors in image area or axes ratio more than 0.5%Comment: accepted to GR

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Measurements of the pp → ZZ production cross section and the Z → 4ℓ branching fraction, and constraints on anomalous triple gauge couplings at √s = 13 TeV

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    Four-lepton production in proton-proton collisions, pp -> (Z/gamma*)(Z/gamma*) -> 4l, where l = e or mu, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb(-1). The ZZ production cross section, sigma(pp -> ZZ) = 17.2 +/- 0.5 (stat) +/- 0.7 (syst) +/- 0.4 (theo) +/- 0.4 (lumi) pb, measured using events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60 4l) = 4.83(-0.22)(+0.23) (stat)(-0.29)(+0.32) (syst) +/- 0.08 (theo) +/- 0.12(lumi) x 10(-6) for events with a four-lepton invariant mass in the range 80 4GeV for all opposite-sign, same-flavor lepton pairs. The results agree with standard model predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ. couplings at 95% confidence level: -0.0012 < f(4)(Z) < 0.0010, -0.0010 < f(5)(Z) < 0.0013, -0.0012 < f(4)(gamma) < 0.0013, -0.0012 < f(5)(gamma) < 0.0013

    Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

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    The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe
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