26,525 research outputs found
Nucleation of Spontaneous Vortices in Trapped Fermi Gases Undergoing a BCS-BEC Crossover
We study the spontaneous formation of vortices during the superfluid
condensation in a trapped fermionic gas subjected to a rapid thermal quench via
evaporative cooling. Our work is based on the numerical solution of the time
dependent crossover Ginzburg-Landau equation coupled to the heat diffusion
equation. We quantify the evolution of condensate density and vortex length as
a function of a crossover phase parameter from BCS to BEC. The more interesting
phenomena occur somewhat nearer to the BEC regime and should be experimentally
observable; during the propagation of the cold front, the increase in
condensate density leads to the formation of supercurrents towards the center
of the condensate as well as possible condensate volume oscillations.Comment: 5 pages, 3 figure
Initial experiments concerning quantum information processing in rare-earth-ion doped crystals
In this paper initial experiments towards constructing simple quantum gates
in a solid state material are presented. Instead of using specially tailored
materials, the aim is to select a subset of randomly distributed ions in the
material, which have the interaction necessary to control each other and
therefore can be used to do quantum logic operations. The experimental results
demonstrate that part of an inhomogeneously broadened absorption line can be
selected as a qubit and that a subset of ions in the material can control the
resonance frequency of other ions. This opens the way for the construction of
quantum gates in rare-earth-ion doped crystals.Comment: 24 pages, including 12 figure
Coulomb gap in the one-particle density of states in three-dimensional systems with localized electrons
The one-particle density of states (1P-DOS) in a system with localized
electron states vanishes at the Fermi level due to the Coulomb interaction
between electrons. Derivation of the Coulomb gap uses stability criteria of the
ground state. The simplest criterion is based on the excitonic interaction of
an electron and a hole and leads to a quadratic 1P-DOS in the three-dimensional
(3D) case. In 3D, higher stability criteria, including two or more electrons,
were predicted to exponentially deplete the 1P-DOS at energies close enough to
the Fermi level. In this paper we show that there is a range of intermediate
energies where this depletion is strongly compensated by the excitonic
interaction between single-particle excitations, so that the crossover from
quadratic to exponential behavior of the 1P-DOS is retarded. This is one of the
reasons why such exponential depletion was never seen in computer simulations.Comment: 6 pages, 1 figur
Three charged particles in the continuum. Astrophysical examples
We suggest a new adiabatic approach for description of three charged
particles in the continuum. This approach is based on the Coulomb-Fourier
transformation (CFT) of three body Hamiltonian, which allows to develop a
scheme, alternative to Born-Oppenheimer one.
The approach appears as an expansion of the kernels of corresponding integral
transformations in terms of small mass-ratio parameter. To be specific, the
results are presented for the system in the continuum. The wave function
of a such system is compared with that one which is used for estimation of the
rate for triple reaction which take place as a step of
-cycle in the center of the Sun. The problem of microscopic screening for
this particular reaction is discussed
Field-Induced Magnetization Steps in Intermetallic Compounds and Manganese Oxides: The Martensitic Scenario
Field-induced magnetization jumps with similar characteristics are observed
at low temperature for the intermetallic germanide Gd5Ge4and the mixed-valent
manganite Pr0.6Ca0.4Mn0.96Ga0.04O3. We report that the field location -and even
the existence- of these jumps depends critically on the magnetic field sweep
rate used to record the data. It is proposed that, for both compounds, the
martensitic character of their antiferromagnetic-to-ferromagnetic transitions
is at the origin of the magnetization steps.Comment: 4 pages,4 figure
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DSMC Modeling Of Gasdynamics, Radiation And Fine Particulates In Ionian Volcanic Jets
Aerospace Engineerin
Somesthetic Functions in Patients with Brain Disease and Normal Subjects
This paper summarizes the results of a series of studies of somatosensory function in normal and brain-diseased subjects that were designed to investigate: (1) neural mechanisms in tactile resolution and masking, and; (2) cerebral dominance and somesthesis. Our results are consistent with the possibility that lateral inhibition effects influence tactile resolution and masking. Additional findings suggest that the physiologic mechanisms involved in tactile masking and obscuration in healthy subjects also mediate the pathologic expressions of these phenomena shown by patients with cerebral disease. Studies of hemispheric dominance and somesthesis have indicated that patients with right hemisphere disease often demonstrate bilateral impairment in tactile perception of direction while this deficit is confined to the right hand of patients with left hemisphere disease. Consistent with the implications of these clinical findings, right-handed normal subjects show a left-hand superiority for tactile perception of direction. Bilateral impairment on a proprioception task was found for patients with unilateral cerebral disease of either hemisphere. However, only patients with right hemisphere lesions were unable to utilize increments in proprioceptive feedback to improve their performance. The results on tactile perception of direction and proprioceptive feedback are interpreted as consistent with findings for other sensory modalities that point to the crucial role of the right hemisphere in spatial aspects of perception
Lipodystrophy syndrome in HIV-infected children on HAART
Lipodystrophy syndrome (LD) is common in HIV-infected children, particularly those taking didanosine, stavudine or zidovudine. Lipo-atrophy in particular causes major stigmatisation and interferes with adherence. In addition, LD may have significant long-term health consequences, particularly cardiovascular. Since the stigmatising fat distribution changes of LD are largely permanent, the focus of management remains on early detection and arresting progression. Practical guidelines for surveillance and avoidance of LD in routine clinical practice are presented. The diagnosis of LD is described and therapeutic options are reviewed. The most important therapeutic intervention is to switch the most likely offending antiretroviral to a non-LD-inducing agent as soon as LD is recognised. Typically, when lipo-atrophy or lipohypertrophy is diagnosed the thymidine nucleoside reverse transcriptase inhibitor (NRTI) is switched to a non-thymidine agent such as abacavir (or tenofovir in adults).Where dyslipidaemia is predominant, a dietician review is helpful, and the clinician may consider switching to a protease inhibitor-sparing regimen or to atazanavir
Evidence-Based Medicine Instruction in Integrative Medical School Curricula: A Tale of Two Libraries
Background:
Many academic health sciences libraries have been moving towards active participation in the curriculum at their institutions.1 At the same time, many medical schools have completed, are working upon or are considering movement to an integrative curriculum, (the melding of basic sciences and clinical learning), based on suggested AAMC competencies.2We will discuss how libraries at two New England medical schools have successfully embraced roles in the their school’s curriculum, which are at different stages of adoption of new integrative curricula.
Methods:
The teaching of Evidence-Based Medicine (EBM) is an area ripe for collaboration between a medical school and its library. The libraries at both Harvard Medical School (HMS) and the University of Massachusetts Medical School (UMMS) now offer EBM instruction within their medical school curricula. HMS is refining its new integrative curriculum while UMMS is in the planning stages with implementation targeted for AY 2010. Teaching time, location within the curriculum, general content and methods between the programs at these two schools will be examined and compared.
Results:
UMMS conducts all of its EBM instruction within a traditional 3rd year clerkship format. HMS covers similar content online in a 1st year combined basic science/clinical course. However, the libraries at both institutions have successfully facilitated the incorporation of this important topic into required coursework.
Reflection:
Reflections on the following themes are included in the poster on: Staff and resources/workload Adding content into a packed curriculum Library expertise In person vs. online instruction Progressive versus single encounter instruction
Conclusions:
While at different phases of curriculum redesign, the academic libraries at UMMS and HMS have demonstrated the effectiveness of varied methods of teaching Evidence-Based Medicine within a medical school curriculum.
1Burrows, Suzetta, et al. Developing an evidence-based medicine and use of the biomedical literature component as a longitudinal theme of an outcomes-based medical school curriculum: year 1. Journal of the Medical Library Association 91.1 (2003):34-41.
2Association of American Medical Colleges. The Education of Medical Students: Ten Stories of Curriculum Change. New York: Milbank Memorial Funds, 2000.
Presented at the Northeast Group on Educational Affairs (NEGEA) Regional Conference on May 2, 2009, in Hershey, Pennsylvania
A Study of Snake Bites Admitted to a Hospital in Rhodesia
A CAJM article on cases of snake bites admitted to a hospital in Harare, Zimbabwe (formerly Salisbury, Rhodesia)The relative abundance of snake species varies geographically. The commonest venomous snakes in Salisbury are probably the Rhombic Nightadder (Causus rhombeatus) (Fig. 1), Egyptian Cobra (Naja Haje) (Fig. 4) and Boomslang (Dispholi- dus typus). In the majority of cases identification of the type of venous bite cannot be obtained as the patient fails to bring the snake to hospital. The purpose of this paper will be to review the main features noted in a retrospective series of 186 cases of snake bite seen at Harare Hospital, Salisbury, between January, 1967, and December, 1971, and to provide a brief account of the main features of the common snakes seen in the Salisbury area
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