1,714 research outputs found

    Delta G from high pT events at SMC and high pT analysis at COMPASS

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    Measurements of the longitudinal spin cross section asymmetry for deep inelastic muon-nucleon interactions with two high transverse momentum hadrons (pT>p_T > 0.7 GeV) in the final state are presented for SMC data for polarized proton and deuteron and for data on polarized deuteron from COMPASS taken in 2002 and 2003. The muon asymmetries determined with a cut on Q2>Q^2> 1 GeV2^2 in SMC are: Ap=0.03±0.057±0.01A_p = 0.03 \pm 0.057\pm 0.01 and Ad=0.070±0.076±0.010A_d = 0.070 \pm 0.076 \pm 0.010, respectively. From these values a gluon polarization ΔG/G=0.20±0.28±0.10\Delta G /G = -0.20\pm 0.28\pm 0.10 was obtained at an average fraction of nucleon momentum carried by gluons η=0.07\eta = 0.07. The measured asymmetry (with cut on Q2>Q^2> 1 GeV2^2) in COMPASS is (Ad/D)=0.015±0.08±0.013(A_d/D) = -0.015 \pm 0.08 \pm 0.013 where D is depolarization factor and the gluon polarization $\Delta G /G = 0.06\pm 0.31\pmComment: 4 pages, 3 figures, Talk given at 10-th International Conference Baryons04, October 25-29, 2004, Ecole Polytechnique, Palaiseau, Franc

    Gluon Polarisation in the Nucleon from COMPASS

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    New results on the longitudinal inclusive asymmetry A1dA^{d}_{1} and the spin-dependent structure function g1dg^{d}_{1} is the range 0.002 (GeV/c)2^{2} 1 (GeV/c)2^{2}) are in agreement with those from previous experiments, improve considerable the statistical accuracy for 0.004 <x<< x < 0.03 region and have been included in new COMPASS NLO QCD analysis of the world data. The new preliminary result for ΔG/G\Delta G/G from the charm channel is -0.57±\pm 0.41(stat.)(stat.) at xGx_{G}\simeq 0.15 and scale μ2\mu^{2}\simeq 13 (GeV/c)2^{2}. The gluon polarization from high-pTp_{T} hadron pairs is ΔG/G=\Delta G/G = 0.016 ±\pm 0.058(stat.)±(stat.) \pm 0.055(syst.)(syst.) at xGx_{G}\simeq 0.0850.0350.07(Q2<^{0.07}_{0.035} (Q^{2} < 1 (GeV/c)2^{2} and μ2\mu^{2}\simeq 3 (GeV/c)2^{2})

    The usability of the optical parametric amplification of light for high-angular-resolution imaging and fast astrometry

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    High-angular-resolution imaging is crucial for many applications in modern astronomy and astrophysics. The fundamental diffraction limit constrains the resolving power of both ground-based and spaceborne telescopes. The recent idea of a quantum telescope based on the optical parametric amplification (OPA) of light aims to bypass this limit for the imaging of extended sources by an order of magnitude or more. We present an updated scheme of an OPA-based device and a more accurate model of the signal amplification by such a device. The semiclassical model that we present predicts that the noise in such a system will form so-called light speckles as a result of light interference in the optical path. Based on this model, we analysed the efficiency of OPA in increasing the angular resolution of the imaging of extended targets and the precise localization of a distant point source. According to our new model, OPA offers a gain in resolved imaging in comparison to classical optics. For a given time-span, we found that OPA can be more efficient in localizing a single distant point source than classical telescopes.Comment: Received: 11 November 2017, revision received: 31 January 2018, accepted: 31 January 201

    Dusty Universe viewed by AKARI far infrared detector

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    We present the results of the analysis of multiwavelength Spectral Energy Distributions (SEDs) of far-infrared galaxies detected in the AKARI Deep Field-South (ADF--S) Survey. The analysis uses a carefully selected sample of 186 sources detected at the 90 μ\mum AKARI band, identified as galaxies with cross-identification in public catalogues. For sources without known spectroscopic redshifts, we estimate photometric redshifts after a test of two independent methods: one based on using mainly the optical -- mid infrared range, and one based on the whole range of ultraviolet -- far infrared data. We observe a vast improvement in the estimation of photometric redshifts when far infrared data are included, compared with an approach based mainly on the optical -- mid infrared range. We discuss the physical properties of our far-infrared-selected sample. We conclude that this sample consists mostly of rich in dust and young stars nearby galaxies, and, furthermore, that almost 25% of these sources are (Ultra)Luminous Infrared Galaxies. Average SEDs normalized at 90 μ\mum for normal galaxies (138 sources), LIRGs (30 sources), and ULIRGs (18 galaxies) a the significant shift in the peak wavelength of the dust emission, and an increasing ratio between their bolometric and dust luminosities which varies from 0.39 to 0.73.Comment: 8 pages, 7 figures, published in Earth, Planets and Spac

    Impact of European Integration on the Functioning of the Insurance Market in Poland

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    The transformation process, that has begun 20 years ago, generated significant changes in the structure and organization of Polish economy. It stimulated development of particular market's segments, especially of the insurance sector. Poland's accession to the European Union required conformity to Its regulations, fulfillment of several conditions connected with the membership in the European Community. The purpose of this article is to present the main consequences of Poland's integration with EU in the field of insurance market. Joining the common market was an important challenge for this sector in our country.Rok 1990 stanowił początek procesu transformacji systemu społeczno - gospodarczego i ustrojowego. Ostatnie 20 lat to okres intensywnych przemian o charakterze strukturalnym i organizacyjnym, w wyniku których ukształtowały się warunki rozwoju poszczególnych segmentów systemu finansowego państwa, zwłaszcza sektora ubezpieczeń. Przystąpienie Polski do Unii Europejskiej wymagało wprowadzenia szeregu zmian, dostosowujących polski porządek prawny do uregulowań wspólnotowych regulujących funkcjonowanie rynku ubezpieczeń. Celem artykułu jest zaprezentowanie szans i zagrożeń, jakie wynikają dla tego segmentu gospodarki z przystąpienia Polski do UE. Niewątpliwie proces integracji stanowił poważne wyzwanie dla polskiego rynku ubezpieczeń

    Nanomechanical Pyrolytic Carbon Resonators: Novel Fabrication Method and Characterization of Mechanical Properties

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    Micro- and nanomechanical string resonators, which essentially are highly stressed bridges, are of particular interest for micro- and nanomechanical sensing because they exhibit resonant behavior with exceptionally high quality factors. Here, we fabricated and characterized nanomechanical pyrolytic carbon resonators (strings and cantilevers) obtained through pyrolysis of photoresist precursors. The developed fabrication process consists of only three processing steps: photolithography, dry etching and pyrolysis. Two different fabrication strategies with two different photoresists, namely SU-8 2005 (negative) and AZ 5214e (positive), were compared. The resonant behavior of the pyrolytic resonators was characterized at room temperature and in high vacuum using a laser Doppler vibrometer. The experimental data was used to estimate the Young’s modulus of pyrolytic carbon and the tensile stress in the string resonators. The Young’s moduli were calculated to be 74 ± 8 GPa with SU-8 and 115 ± 8 GPa with AZ 5214e as the precursor. The tensile stress in the string resonators was 33 ± 7 MPa with AZ 5214e as the precursor. The string resonators displayed maximal quality factor values of up to 3000 for 525-µm-long structures

    Variation of selected cyclic properties depending on temperature of the test

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    Determination of fatigue life involves many factors, among them temperature in which the structure is working. Based on the literature data, the authors present the influence of temperature on cyclic properties of the selected materials. Further analysis proves that, in the case of alloyed steels, temperature affects some quantities characterizing fatigue parameters.Констатовано, що умови експлуатації елементів машин і пристроїв, які використовують в енергетиці, характеризуються змінами температури від кімнатної до дуже високої. Це призводить до істотної зміни механічних властивостей досліджуваних матеріалів. В результаті аналізу зміни вибраних циклічних властивостей залежно від температури встановлено основні закономірності для низьколегованих сталей і високолегованих чавунів.Констатировано, что условия эксплуатации элементов машин и устройств, которые используют в энергетике характеризуются изменениями температуры от комнатной до весьма высокой. Это приводит к существенному изменению механических свойств исследуемых материалов. В результате анализа изменения избранных циклических свойств в зависимости от температуры установлено основные закономерности для низколегированных сталей и высоколегированных чугунов

    The use of dithiothreitol for the quantitative analysis of elemental sulfur concentrations and isotopes in environmental samples

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    Determining the concentration and isotopic composition of elemental sulfur in modern and ancient environments is essential to improved interpretation of the mechanisms and pathways of sulfur utilization in biogeochemical cycles. Elemental sulfur can be extracted from sediment or water samples and quantified by converting to hydrogen sulfide. Alternatively, elemental sulfur concentrations can themselves be analyzed using HPLC and other methodologies; however, the preparation and analysis times can be long and these methods are not amenable to stable isotopic analysis. Current reduction methods involve the use of costly and specialized glassware in addition to toxins such as chromium chloride or cyanide to reduce the sulfur to hydrogen sulfide. The novel reduction method presented here uses dithiothreitol (DTT) as a less toxic reducing agent to obtain both elemental sulfur concentrations and isotopic composition from the same sample. The sample is dissolved in an aqueous or organic liquid medium and upon reaction with DTT, the elemental sulfur is volatilized as hydrogen sulfide and collected in a sulfide trap using an inexpensive gas extraction apparatus. The evolved sulfide concentrations can easily be measured for concentration, by absorbance spectrophotometery or voltammetry techniques, and then analyzed for sulfur isotopic composition. The procedure is quantitative at >93% recovery to dissolved elemental sulfur with no observed sulfur isotope fractionation during reduction and recovery. Controlled experiments also demonstrate that DTT is not reactive to sulfate, sulfite, pyrite, or organic sulfur
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