87,156 research outputs found
Path integral for a relativistic Aharonov-Bohm-Coulomb system
The path integral for the relativistic spinless Aharonov-Bohm-Coulomb system
is solved, and the energy spectra are extracted from the resulting amplitude.Comment: 6 pages, Revte
Green's function for the Relativistic Coulomb System via Sum Over Perturbation Series
We evaluate the Green's function of the D-dimensional relativistic Coulomb
system via sum over perturbation series which is obtained by expanding the
exponential containing the potential term in the path integral
into a power series. The energy spectra and wave functions are extracted from
the resulting amplitude.Comment: 13 pages, ReVTeX, no figure
Development of learning objectives for neurology in a veterinary curriculum: part I: undergraduates
Background
With an increasing caseload of veterinary neurology patients in first opinion practice, there is a requirement to establish relevant learning objectives for veterinary neurology encompassing knowledge, skills and attitudes for veterinary undergraduate students in Europe. With help of experts in veterinary neurology from the European College of Veterinary Neurology (ECVN) and the European Society of Veterinary Neurology (ESVN) a survey of veterinary neurologic learning objectives using a modified Delphi method was conducted. The first phase comprised the development of a draft job description and learning objectives by a working group established by the ECVN. In the second phase, a quantitative questionnaire (multiple choice, Likert scale and free text) covering 140 learning objectives and subdivided into 8 categories was sent to 341 ESVN and ECVN members and a return rate of 62% (n = 213/341) was achieved.
Results
Of these 140 learning objectives ECVN Diplomates and ESVN members considered 42 (30%) objectives as not necessary for standard clinical veterinary neurology training, 94 (67%) were graded to be learned at a beginner level and 4 (3%) at an advanced level. The following objectives were interpreted as the most important day one skills: interpret laboratory tests, perform a neurological examination and establish a neuroanatomical localization. In this survey the three most important diseases of the central nervous system included epilepsy, intervertebral disc disease and inflammatory diseases. The three most important diseases of the peripheral nervous system included polyradiculoneuritis, myasthenia gravis and toxic neuropathies.
Conclusions
The results of this study should help to reform the veterinary curriculum regarding neurology and may reduce the phenomenon of “Neurophobia”.</p
Decoherence and the rate of entropy production in chaotic quantum systems
We show that for an open quantum system which is classically chaotic (a
quartic double well with harmonic driving coupled to a sea of harmonic
oscillators) the rate of entropy production has, as a function of time, two
relevant regimes: For short times it is proportional to the diffusion
coefficient (fixed by the system--environment coupling strength). For longer
times (but before equilibration) there is a regime where the entropy production
rate is fixed by the Lyapunov exponent. The nature of the transition time
between both regimes is investigated.Comment: Revtex, 4 pages, 3 figures include
CD4+ T-cell responses to Epstein-Barr virus nuclear antigen EBNA1 in Chinese populations are highly focused on novel C-terminal domain-derived epitopes
Epstein-Barr virus nuclear antigen EBNA1, the one viral protein uniformly expressed in nasopharyngeal carcinoma (NPC), represents a prime target for T-cell-based immunotherapy. However, little is known about the EBNA1 epitopes, particularly CD4 epitopes, presented by HLA alleles in Chinese people, the group at highest risk for NPC. We analyzed the CD4 T-cell responses to EBNA1 in 78 healthy Chinese donors and found marked focusing on a small number of epitopes in the EBNA1 C-terminal region, including a DP5- restricted epitope that was recognized by almost half of the donors tested and elicited responses able to recognize EBNA1-expressing, DP5-positive target cells
Configuration-Space Location of the Entanglement between Two Subsystems
In this paper we address the question: where in configuration space is the
entanglement between two particles located? We present a thought-experiment,
equally applicable to discrete or continuous-variable systems, in which one or
both parties makes a preliminary measurement of the state with only enough
resolution to determine whether or not the particle resides in a chosen region,
before attempting to make use of the entanglement. We argue that this provides
an operational answer to the question of how much entanglement was originally
located within the chosen region. We illustrate the approach in a spin system,
and also in a pair of coupled harmonic oscillators. Our approach is
particularly simple to implement for pure states, since in this case the
sub-ensemble in which the system is definitely located in the restricted region
after the measurement is also pure, and hence its entanglement can be simply
characterised by the entropy of the reduced density operators. For our spin
example we present results showing how the entanglement varies as a function of
the parameters of the initial state; for the continuous case, we find also how
it depends on the location and size of the chosen regions. Hence we show that
the distribution of entanglement is very different from the distribution of the
classical correlations.Comment: RevTex, 12 pages, 9 figures (28 files). Modifications in response to
journal referee
Charmed-Baryon Spectroscopy from Lattice QCD with N_f=2+1+1 Flavors
We present the results of a calculation of the positive-parity ground-state
charmed-baryon spectrum using 2+1+1 flavors of dynamical quarks. The
calculation uses a relativistic heavy-quark action for the valence charm quark,
clover-Wilson fermions for the valence light and strange quarks, and HISQ sea
quarks. The spectrum is calculated with a lightest pion mass around 220 MeV,
and three lattice spacings (a \approx 0.12 fm, 0.09 fm, and 0.06 fm) are used
to extrapolate to the continuum. The light-quark mass extrapolation is
performed using heavy-hadron chiral perturbation theory up to O(m_pi^3) and at
next-to-leading order in the heavy-quark mass. For the well-measured charmed
baryons, our results show consistency with the experimental values. For the
controversial J=1/2 Xi_{cc}, we obtain the isospin-averaged value
M_{Xi_{cc}}=3595(39)(20)(6) MeV (the three uncertainties are statistics,
fitting-window systematic, and systematics from other lattice artifacts, such
as lattice scale setting and pion-mass determination), which shows a 1.7 sigma
deviation from the experimental value. We predict the yet-to-be-discovered
doubly and triply charmed baryons Xi_{cc}^*, Omega_{cc}, Omega_{cc}^* and
Omega_{ccc} to have masses 3648(42)(18)(7) MeV, 3679(40)(17)(5) MeV,
3765(43)(17)(5) MeV and 4761(52)(21)(6) MeV, respectively.Comment: 23 pages, 14 figure
- …