21,437 research outputs found
Strange stars at finite temperature
We calculate strange star properties, using large N_c approximation with
built-in chiral symmetry restoration (CSM). We used a relativistic Hartree Fock
mean field approximation method, using a modified Richardson potential with two
scale parameters \Lambda and \Lambda^\prime, to find a new set of equation of
states for strange quark matter. We take the effect of temperature (T) on gluon
mass, in addition to the usual density dependence, and find that the transition
T from hadronic matter to strange matter is 80 MeV. Therefore formation of
strange stars may be the only signal for formation of QGP with asymptotic
freedom and CSM.Comment: To be published in the proceedings of The Third 21COE Symposium, held
at Department of Physics, Waseda University, Tokyo, Japan, September 1-3,
200
Deriving modified rankin scores from medical records
<p><b>Background and Purpose:</b> Modified Rankin score (mRS) is traditionally graded using a face-to-face or telephone interview. Certain stroke assessment scales can be derived from a review of a patient’s case-record alone. We hypothesized that mRS could be successfully derived from the narrative within patient case-records.</p>
<p><b>Methods:</b> Sequential patients attending our cerebrovascular outpatient clinic were included. Two independent, blinded clinicians, trained in mRS, assessed case-records to derive mRS. They scored “certainty” of their grading on a 5-point Likert scale. Agreement between derived and traditional face-to-face mRS was calculated using attribute agreement analysis.</p>
<p><b>Results:</b> Fifty patients with a range of disabilities were included. Case-record appraisers were poor at deriving mRS (k=0.34 against standard). Derived mRS grades showed poor agreement between observers (k=0.33). There was no relationship between certainty of derived mRS and proportion of correct grades (P=0.727).</p>
<p><b>Conclusion:</b> Accurate mRS cannot be derived from standard hospital records. Direct mRS interview is still required for clinical trials.</p>
Electron paramagnetic resonance, optical absorption and Raman spectral studies on a pyrite/chalcopyrite mineral
Pyrite and chalcopyrite mineral samples from Mangampet barite mine, Kadapa, Andhra Pradesh, India are used in the present study. XRD data indicate that the pyrite mineral has a face centered cubic lattice structure with lattice constant 5.4179 Ă…. Also it possesses an average particle size of 91.9 nm. An EPR study on the powdered samples confirms the presence of iron in pyrite and iron and Mn(II) in chalcopyrite. The optical absorption spectrum of chalcopyrite indicates presence of copper which is in a distorted octahedral environment. NIR results confirm the presence of water fundamentals and Raman spectrum reveals the presence of water and sulfate ions
Squeezing and entanglement of matter-wave gap solitons
We study quantum squeezing and entanglement of gap solitons in a
Bose-Einstein condensate loaded into a one-dimensional optical lattice. By
employing a linearized quantum theory we find that quantum noise squeezing of
gap solitons, produced during their evolution, is enhanced compared with the
atomic solitons in a lattice-free case due to intra-soliton structure of
quantum correlations induced by the Bragg scattering in the periodic potential.
We also show that nonlinear interaction of gap solitons in dynamically stable
bound states can produce strong soliton entanglement.Comment: 4 pages, 5 figure
Radiative corrections and quantum gates in molecular systems
We propose a method for quantum information processing using molecules
coupled to an external laser field. This utilizes molecular interactions,
control of the external field and an effective energy shift of the
doubly-excited state of two coupled molecules. Such a level shift has been seen
in the two-photon resonance experiments recently reported in Ref. [1]. Here we
show that this can be explained in terms of the QED Lamb shift. We quantify the
performance of the proposed quantum logic gates in the presence of dissipative
mechanisms. The unitary transformations required for performing one- and
two-qubit operations can be implemented with present day technology.Comment: 4 pages, 3 figures, Updated to correct important missing referenc
Susceptibilities and speed of sound from PNJL model
We present the Taylor expansion coefficients of the pressure in quark number
chemical potential , for the strongly interacting
matter as described by the PNJL model for two light degenerate flavours of
quarks u and d. The expansion has been done upto eighth order in , and
the results are consistent with recent estimates from Lattice. We have further
obtained the specific heat , squared speed of sound and the
conformal measure \cC.Comment: 13 pages, 8 figures, References added, some discussions on Fig. 4
modified, one table added, results unchanged, version to appear in Phys. Rev.
- …