7,748 research outputs found

    Search for WW and WZ production in lepton plus jets final state at CDF

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    We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in sqrt(s) = 1.96 TeV ppbar collisions at the Fermilab Tevatron, using data corresponding to 1.2 fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of sigma_{WW}* BR(W->lnu,W->jets)+ sigma_{WZ}*BR(W->lnu,Z->jets)We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in √s=1.96  TeV pp̅ collisions at the Fermilab Tevatron, using data corresponding to 1.2  fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of σWW×BR(W→ℓνℓ,W→jets)+σWZ×BR(W→ℓνℓ,Z→jets)<2.88  pb, which is consistent with the standard model next-to-leading-order cross section calculation for this decay channel of 2.09±0.12  pb.Peer reviewe

    Which phase is measured in the mesoscopic Aharonov-Bohm interferometer?

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    Mesoscopic solid state Aharonov-Bohm interferometers have been used to measure the "intrinsic" phase, αQD\alpha_{QD}, of the resonant quantum transmission amplitude through a quantum dot (QD). For a two-terminal "closed" interferometer, which conserves the electron current, Onsager's relations require that the measured phase shift β\beta only "jumps" between 0 and π\pi. Additional terminals open the interferometer but then β\beta depends on the details of the opening. Using a theoretical model, we present quantitative criteria (which can be tested experimentally) for β\beta to be equal to the desired αQD\alpha_{QD}: the "lossy" channels near the QD should have both a small transmission and a small reflection

    Gastric Osteoma in a Dog

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    An eight year old female dog was referred with anorexia, nervousness and emaciation. At the point of time, severe lifelessness was the only symptom. Then euthanasia was done according to the owner’s decision. As a result of postmortem examination, thin white matters were found on the gastric mucosa of the greater curvature and there were no other significant gross findings. Tissue specimens were collected from the gastric wall, esophagus, gall bladder, aorta, heart, kidneys, liver, mesenteric lymph node, lungs, urinary bladder and spleen and processed for histopathology. Microscopically, the masses of stomach were consisted of well-differentiated osteoid tissues, the compact bone-osteocytes and the matured lamellated bone with Haversian system. It was diagnosed as osteoma of the stomach. Other organs were free on such histological findings

    Determinants of whistleblowing intention : evidence from the South Korean government

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    In 2001, the South Korean government passed the Anti-Corruption Act, which provides whistleblower protection in the public sector. The system of protections and rewards was strengthened in 2011 by the Act on the Protection of Public Interest Whistleblowers. Although these laws ensure immunity—and even financial incentives—for whistleblowers, whistleblowing is still not a straightforward task. Based on a survey of 5706 public officials in central government, this study examines how a range of factors influence whistleblowing intention: attitude; knowledge; colleague support; organizational support; and protection against retaliation. A number of demographic variables, relating to gender; marital status; length of tenure; duty; and position type are used as controls. The results of the ordered probit regression analysis show all of the independent variables to have a significant positive effect on whistleblowing intention. However, colleague support and organizational support have the biggest effects, while perceived protection against retaliation has the smallest. This suggests that there is a need for future government efforts to build upon the available legal protections by focusing on creating a supportive culture among colleagues and in the organization more generally

    A critical review of the formation of mono- and dicarboxylated metabolic intermediates of alkylphenol polyethoxylates during wastewater treatment and their environmental significance

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Taylor & Francis.Alkylphenoxyacetic acids, the metabolic biodegradation products of alkylphenol ethoxylates, are commonly found in wastewaters and sewage effluents. These persistent hydrophilic derivatives possess intrinsic estrogenic activity, which can mimic natural hormones. Their concentrations increase through the sewage treatment works as a result of biodegradation and biotransformation, and when discharged can disrupt endocrine function in fish. These acidic metabolites represent the dominant alkylphenolic compounds found in wastewater effluent and their presence is cause for concern as, potentially, through further biotransformation and biodegradation, they can act as sources of nonylphenol, which is toxic and estrogenic. The authors aim to assess the mechanisms of formation as well as elimination of alkylphenoxyacetic acids within conventional sewage treatment works with the emphasis on the activated sludge process. In addition, they evaluate the various factors influencing their degradation and formation in laboratory scale and full-scale systems. The environmental implications of these compounds are considered, as is the need for tertiary treatment processes for their removal

    Tunneling in the topological mechanism of superconductivity

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    We compute the two-particle matrix element and Josephson tunneling amplitude in a two-dimensional model of topological superconductivity which captures the physics of the doped Mott insulator. The hydrodynamics of topological electronic liquid consists of the compressible charge sector and the incompressible chiral topological spin liquid. We show that ground states differing by an odd number of particles are orthogonal and insertion of two extra electrons is followed by the emission of soft modes of the transversal spin current. The orthogonality catastrophe makes the physics of superconductivity drastically different from the BCS-theory but similar to the physics of one-dimensional electronic liquids. The wave function of a pair is dressed by soft modes. As a result the two particle matrix element forms a complex d-wave representation (i.e., changes sign under 90o90^o degree rotation), although the gap in the electronic spectrum has no nodes. In contrast to the BCS-theory the tunneling amplitude has an asymmetric broad peak (much bigger than the gap) around the Fermi surface. We develop an operator algebra, that allows one to compute other correlation functions.Comment: 18 pages, 2 eps figures, revtex, psfig, significant changes have been mad

    Interpretation of Strong Short-Term Central Perturbations in the Light Curves of Moderate-Magnification Microlensing Events

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    To improve the planet detection efficiency, current planetary microlensing experiments are focused on high-magnification events searching for planetary signals near the peak of lensing light curves. However, it is known that central perturbations can also be produced by binary companions and thus it is important to distinguish planetary signals from those induced by binary companions. In this paper, we analyze the light curves of microlensing events OGLE-2007-BLG-137/MOA-2007-BLG-091, OGLE-2007-BLG-355/MOA-2007-BLG-278, and MOA-2007-BLG-199/OGLE-2007-BLG-419, for all of which exhibit short-term perturbations near the peaks of the light curves. From detailed modeling of the light curves, we find that the perturbations of the events are caused by binary companions rather than planets. From close examination of the light curves combined with the underlying physical geometry of the lens system obtained from modeling, we find that the short time-scale caustic-crossing feature occurring at a low or a moderate base magnification with an additional secondary perturbation is a typical feature of binary-lens events and thus can be used for the discrimination between the binary and planetary interpretations.Comment: 17 pages, 4 figures, 1 tabl

    Curricular orientations to real-world contexts in mathematics

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    A common claim about mathematics education is that it should equip students to use mathematics in the ‘real world’. In this paper, we examine how relationships between mathematics education and the real world are materialised in the curriculum across a sample of eleven jurisdictions. In particular, we address the orientation of the curriculum towards application of mathematics, the ways that real-world contexts are positioned within the curriculum content, the ways in which different groups of students are expected to engage with real-world contexts, and the extent to which high-stakes assessments include real-world problem solving. The analysis reveals variation across jurisdictions and some lack of coherence between official orientations towards use of mathematics in the real world and the ways that this is materialised in the organisation of the content for students
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