561 research outputs found
Superconducting fluctuations and the Nernst effect: A diagrammatic approach
We calculate the contribution of superconducting fluctuations above the
critical temperature to the transverse thermoelectric response
, the quantity central to the analysis of the Nernst effect. The
calculation is carried out within the microscopic picture of BCS, and to linear
order in magnetic field. We find that as , the dominant contribution
to arises from the Aslamazov-Larkin diagrams, and is equal to the
result previously obtained from a stochastic time-dependent Ginzburg-Landau
equation [Ussishkin, Sondhi, and Huse, arXiv:cond-mat/0204484]. We present an
argument which establishes this correspondence for the heat current. Other
microscopic contributions, which generalize the Maki-Thompson and density of
states terms for the conductivity, are less divergent as .Comment: 11 pages, 5 figure
Spin pumping and magnetization dynamics in metallic multilayers
We study the magnetization dynamics in thin ferromagnetic films and small
ferromagnetic particles in contact with paramagnetic conductors. A moving
magnetization vector causes \textquotedblleft pumping\textquotedblright of
spins into adjacent nonmagnetic layers. This spin transfer affects the
magnetization dynamics similar to the Landau-Lifshitz-Gilbert phenomenology.
The additional Gilbert damping is significant for small ferromagnets, when the
nonmagnetic layers efficiently relax the injected spins, but the effect is
reduced when a spin accumulation build-up in the normal metal opposes the spin
pumping. The damping enhancement is governed by (and, in turn, can be used to
measure) the mixing conductance or spin-torque parameter of the
ferromagnet--normal-metal interface. Our theoretical findings are confirmed by
agreement with recent experiments in a variety of multilayer systems.Comment: 10 pages, 6 figure
REVOLUTION (Routine EValuatiOn of people LivIng with caNcer)âprotocol for a prospective characterisation study of patients with incurable cancer
Introduction: There is a pressing need for a holistic characterisation of people with incurable cancer. In this group, where quality of life and improvement of symptoms are therapeutic priorities, the physical and biochemical manifestations of cancer are often studied separately, giving an incomplete picture. In order to improve care, spur therapeutic innovation, provide meaningful endpoints for trials and set priorities for future research, work must be done to explore how the tumour influences the clinical phenotype. Characterisation of the host-tumour interaction may also provide information regarding prognosis, allowing appropriate planning of investigations, treatment and referral to palliative medicine services. Methods: Routine EValuatiOn of people LivIng with caNcer (REVOLUTION) is a prospective observational study that aims to characterise people with incurable cancer around five key areas, namely body composition, physical activity, systemic inflammatory response, symptoms, and quality of life by developing a bio-repository. Participants will initially be recruited from a single centre in the UK and will have assessments of body composition (bio-impedance analysis [BIA] and computed tomography [CT]), assessment of physical activity using a physical activity monitor, measurement of simple markers of inflammation and plasma cytokine proteins and three symptom and quality of life questionnaires. Discussion: This study aims to create a comprehensive biochemical and clinical characterisation of people with incurable cancer. Data in this study can be used to give a better understanding of the âsymptom phenotypeâ and quality of life determinants, development of a profile of the systemic inflammatory response and a detailed characterisation of body composition
A narrative analysis of career transition themes and outcomes using chaos theory as a guiding metaphor
In a rapidly changing world of work little research exists on mid-career transitions. We investigated these using the open-systems approach of chaos theory as a guiding metaphor and conducted interviews with seven mid-career individuals chosen for their experience of a significant mid-career transition. Four common themes were identified through narrative analysis, where âfalse startsâ to a career were a common experience prior to finding a career âfitâ. Career transitions, precipitated by a trigger state and/or event such as a period of disillusionment, were an important part of this âfinding a fitâ process. Overall, career success outcomes were shaped by a combination of chaos elements: chance, unplanned events, and non-linearity of resultant outcomes. We discuss implications for future research and for practice
Nurture, nature and some very dubious social skills: An interpretative phenomenological analysis of talent identification practices in elite English youth soccer
This paper reports qualitative findings regarding the concepts and practices utilised in talent identification (TI) among professional coaches working in English youth soccer. Using interpretative phenomenological analysis, detailed interviews with seven such coaches are explored, with a view to elucidating the links between understanding, practice, experience and professional context. Findings reveal three superordinate themes, relating to (1) a primarily ânurturedâ and trainable understanding of the broad concept of talent itself, (2) an ostensibly contradictory model of semi-static player psychology, and (3) a highly selective mechanism for separating evidence for âmental strengthâ and âsocial skillsâ. It is contended that these findings underscore a case for more thorough interrogation of the real worlds inhabited by coaches, such that ideas about âgood practiceâ in TI might be more effectively reconciled with grounded knowledge of the practical everyday necessities of being a coach
Sensitivity of the IceCube Detector to Astrophysical Sources of High Energy Muon Neutrinos
We present the results of a Monte-Carlo study of the sensitivity of the
planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV
energies. A complete simulation of the detector and data analysis is used to
study the detector's capability to search for muon neutrinos from sources such
as active galaxies and gamma-ray bursts. We study the effective area and the
angular resolution of the detector as a function of muon energy and angle of
incidence. We present detailed calculations of the sensitivity of the detector
to both diffuse and pointlike neutrino emissions, including an assessment of
the sensitivity to neutrinos detected in coincidence with gamma-ray burst
observations. After three years of datataking, IceCube will have been able to
detect a point source flux of E^2*dN/dE = 7*10^-9 cm^-2s^-1GeV at a 5-sigma
significance, or, in the absence of a signal, place a 90% c.l. limit at a level
E^2*dN/dE = 2*10^-9 cm^-2s^-1GeV. A diffuse E-2 flux would be detectable at a
minimum strength of E^2*dN/dE = 1*10^-8 cm^-2s^-1sr^-1GeV. A gamma-ray burst
model following the formulation of Waxman and Bahcall would result in a 5-sigma
effect after the observation of 200 bursts in coincidence with satellite
observations of the gamma-rays.Comment: 33 pages, 13 figures, 6 table
On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes
The sensitivity of a search for sources of TeV neutrinos can be improved by
grouping potential sources together into generic classes in a procedure that is
known as source stacking. In this paper, we define catalogs of Active Galactic
Nuclei (AGN) and use them to perform a source stacking analysis. The grouping
of AGN into classes is done in two steps: first, AGN classes are defined, then,
sources to be stacked are selected assuming that a potential neutrino flux is
linearly correlated with the photon luminosity in a certain energy band (radio,
IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on neutrino
production in AGN, this correlation is motivated by hadronic AGN models, as
briefly reviewed in this paper.
The source stacking search for neutrinos from generic AGN classes is
illustrated using the data collected by the AMANDA-II high energy neutrino
detector during the year 2000. No significant excess for any of the suggested
groups was found.Comment: 43 pages, 12 figures, accepted by Astroparticle Physic
10 Myr evolution of sedimentation rates in a deep marine to non-marine foreland basin system: Tectonic and sedimentary controls (Eocene, TrempâJaca Basin, Southern Pyrenees, NE Spain)
The propagation of the deformation front in foreland systems is typically accompanied by the incorporation of parts of the basin into wedge-top piggy-back basins, this process is likely producing considerable changes to sedimentation rates (SR). Here we investigate the spatial-temporal evolution of SR for the TrempâJaca Basin in the Southern Pyrenees during its evolution from a wedge-top, foreredeep, forebulge configuration to a wedge-top stage. SR were controlled by a series of tectonic structures that influenced subsidence distribution and modified the sediment dispersal patterns. We compare the decompacted SR calculated from 12 magnetostratigraphic sections located throughout the TrempâJaca Basin represent the full range of depositional environment and times. While the derived long-term SR range between 9.0 and 84.5Â cm/kyr, compiled data at the scale of magnetozones (0.1â2.5Â Myr) yield SR that range from 3.0 to 170Â cm/kyr. From this analysis, three main types of depocenter are recognized: a regional depocenter in the foredeep depozone; depocenters related to both regional subsidence and salt tectonics in the wedge-top depozone; and a depocenter related to clastic shelf building showing transgressive and regressive trends with graded and non-graded episodes. From the evolution of SR we distinguish two stages. The Lutetian Stage (from 49.1â41.2Â Ma) portrays a compartmentalized basin characterized by variable SR in dominantly underfilled accommodation areas. The markedly different advance of the deformation front between the Central and Western Pyrenees resulted in a complex distribution of the foreland depozones during this stage. The BartonianâPriabonian Stage (41.2â36.9Â Ma) represents the integration of the whole basin into the wedge-top, showing a generalized reduction of SR in a mostly overfilled relatively uniform basin. The stacking of basement units in the hinterland during the whole period produced unusually high SR in the wedge-top depozoneAgĂšncia de GestiĂł d'Ajuts Universitaris i de Recerca, Grant/Award Number: 2017SGR596; SecretarĂa de Estado de InvestigaciĂłn, Desarrollo e InnovaciĂłn, Grant/Award Number: BES-2015-073302 and CGL2014-55900-P; Swiss National Science Foundation, Grant/Award Number: 200020_18201
Detector Description and Performance for the First Coincidence Observations between LIGO and GEO
For 17 days in August and September 2002, the LIGO and GEO interferometer
gravitational wave detectors were operated in coincidence to produce their
first data for scientific analysis. Although the detectors were still far from
their design sensitivity levels, the data can be used to place better upper
limits on the flux of gravitational waves incident on the earth than previous
direct measurements. This paper describes the instruments and the data in some
detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial
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