4,385 research outputs found

    Spin-dependent pump current and noise in an adiabatic quantum pump based on domain walls in a magnetic nanowire

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    We study the pump current and noise properties in an adiabatically modulated magnetic nanowire with double domain walls (DW). The modulation is brought about by applying a slowly oscillating magnetic and electric fields with a controllable phase difference. The pumping mechanism resembles the case of the quantum dot pump with two-oscillating gates. The pump current, shot noise, and heat flow show peaks when the Fermi energy matches with the spin-split resonant levels localized between the DWs. The peak height of the pump current is an indicator for the lifetime of the spin-split quasistationary states between the DWs. For sharp DWs, the energy absorption from the oscillating fields results in side-band formations observable in the pump current. The pump noise carries information on the correlation properties between the nonequilibrium electrons and the quasi-holes created by the oscillating scatterer. The ratio between the pump shot noise and the heat flow serves as an indicator for quasi-particle correlation.Comment: 18 pages, 5 figure

    Some issues in data model mapping

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    Numerous data models have been reported in the literature since the early 1970's. They have been used as database interfaces and as conceptual design tools. The mapping between schemas expressed according to the same data model or according to different models is interesting for theoretical and practical purposes. This paper addresses some of the issues involved in such a mapping. Of special interest are the identification of the mapping parameters and some current approaches for handling the various situations that require a mapping

    Does land use and landscape contribute to self-harm? A sustainability cities framework

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    Self-harm has become one of the leading causes of mortality in developed countries. The overall rate for suicide in Canada is 11.3 per 100,000 according to Statistics Canada in 2015. Between 2000 and 2007 the lowest rates of suicide in Canada were in Ontario, one of the most urbanized regions in Canada. However, the interaction between land use, landscape and self-harm has not been significantly studied for urban cores. It is thus of relevance to understand the impacts of land-use and landscape on suicidal behavior. This paper takes a spatial analytical approach to assess the occurrence of self-harm along one of the densest urban cores in the country: Toronto. Individual self-harm data was gathered by the National Ambulatory Care System (NACRS) and geocoded into census tract divisions. Toronto’s urban landscape is quantified at spatial level through the calculation of its land use at di erent levels: (i) land use type, (ii) sprawl metrics relating to (a) dispersion and (b) sprawl/mix incidence; (iii) fragmentation metrics of (a) urban fragmentation and (b) density and (iv) demographics of (a) income and (b) age. A stepwise regression is built to understand the most influential factors leading to self-harm from this selection generating an explanatory model.This research was supported by the Canadian Institutes of Health Research Strategic Team Grant in Applied Injury Research # TIR-103946 and the Ontario Neurotrauma Foundation grantinfo:eu-repo/semantics/publishedVersio

    Drell-Yan production and Lam-Tung relation in the Color Glass Condensate formalism

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    We study the Drell-Yan production cross section and structure functions in proton (deuteron)-nucleus collisions using the Color Glass Condensate formalism. The nucleus is treated in the Color Glass Condensate framework which includes both higher twist effects due to the inclusion of multiple scatterings and leading twist pQCD shadowing due to the small x resummation, while the proton (or deuteron) is treated within the DGLAP improved parton model. In particular, the Drell-Yan structure functions are used in order to investigate the Lam-Tung relation at small x, which is known to be identically zero at leading twist up to Next-to-Leading order, and is thus a good playground for studying higher twist effects. In agreement with this, we find that violations of this relation are more important for low momentum and invariant mass of the Drell-Yan pair, and also in the region of rapidity that corresponds to smaller values of x in the nucleus.Comment: 25 pages, 16 postscript figure

    Screening for HLA-B*1502 Polymorphism in Febrile Seizure Predicted Lead to Epilepsy

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    Mutation in neuronal sodium channel -1-subunit gene (SCN1A) and neuronal sodium channel -1-subunit gene (SCN1B) has been linked with forms of generalized epilepsy with febrile seizure plus (GEFS+) and epileptic infantile syndrome like severe myoclonic epilepsy of infancy (SMEI) (Mulley et al., 2005; Scheffer et al., 2007). Since this idiopathic epilepsy typically begins with prolonged febrile seizures (FS) in the first year of life, therefore febrile seizure patient with mutation in SCN1A has a high risk to develop epilepsy on their later life (Dube et al., 2009). Carbamazepine (CBZ) has been known as the most common anti-epileptic drug which can cause Steven-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) in patients with HLA-B*1502 polymorphism. Since the Javanese population have 16,67% of these allele, studying the presence of these allele in patients predicted epilepsy is important. Furthermore, this study was intended to develop a PCR-based diagnostic protocol to screen HLA-B*1502 polymorphism in epileptic patients to prevent SJS/TEN by carbamazepine. Focusing on epileptic predicted patients, HLA-B*1502 genotyping by sequence specific primer (SSP)-PCR was performed on 31 repeated FS patients with mutation in SCN1A and SCN1A/SCN1B gene. The result show that the HLA-B*1502 polymorphism was detected in 14 (45,2%) individuals including 8 cases related to mutation SCN1A gene and 6 to SCN1A/SCN1B gene. It illustrates that HLA-B*1502 allele is frequent in these patients. It can thus be suggested that detection of this allele should be done before epilepsy treatment. Later, patients with this allele should avoid CBZ to prevent SJS/TEN during drug administration

    Magnetization reversal and spin dynamics exchange in biased F/AF bilayers probed with complex permeability spectra

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    The spin dynamics of the ferromagnetic pinned layer of ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad frequency range (30 MHz-6 GHz). A phenomenological model based on the Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is proposed. The experimental results are compared to theoretical predictions. We show that the resonance frequencies, measured during the magnetization, are likewise hysteretic.Comment: 4 pages, 4 figure

    Constraints on stable equilibria with fluctuation-induced forces

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    We examine whether fluctuation-induced forces can lead to stable levitation. First, we analyze a collection of classical objects at finite temperature that contain fixed and mobile charges, and show that any arrangement in space is unstable to small perturbations in position. This extends Earnshaw's theorem for electrostatics by including thermal fluctuations of internal charges. Quantum fluctuations of the electromagnetic field are responsible for Casimir/van der Waals interactions. Neglecting permeabilities, we find that any equilibrium position of items subject to such forces is also unstable if the permittivities of all objects are higher or lower than that of the enveloping medium; the former being the generic case for ordinary materials in vacuum.Comment: 4 pages, 1 figur

    Allosteric modulation of beta1 integrin function induces lung repair in animal model of emphysema.

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    Emphysema is a progressive lung disease characterised by loss of lung parenchyma with associated functional changes including decreased tissue elastance. Here we report beta1 integrin is a novel target for tissue repair and regeneration in emphysema. We show a single dose of a monoclonal antibody against beta1 integrin induced both functional and structural reversal of elastase-induced lung injury in vivo, and we found that similar matrix remodelling changes occurred in human lung tissue. We also identified a potential mechanism of action as this allosteric modulation of beta1 integrin inhibited elastase-induced caspase activation, F-actin aggregate formation and changes in cellular ATP levels. This was accompanied by maintenance of beta1?integrin levels and inhibition of caveolin-1 phosphorylation. We propose that allosteric modulation of beta1 integrin-mediated mechanosensing prevents cell death associated with lung injury and progressive emphysema, thus allowing cells to survive and for repair and regeneration to ensue
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