826 research outputs found
On Common Fixed Point Theorem in Intuitionistic Fuzzy Metric Spaces with Rational Inequality
: In this paper, we use the concepts of subcompatibility and subsequential continuity in Intuitionistic Fuzzy Metric Spaces which are respectively weaker than occasionally weak compatibility and reciprocal continuity. With them, we establish a common fixed point theorem for four mapstaking rational inequality. AMS Subject Classification Codes: 47H10, 54H25 Keywords:Intuitionistic fuzzy metric space, Subcompatibility and Subsequential continuity, common fixed point theorem, implicit relation
A comparative study of granisetrone, dexamethasone and combination of granisetrone-dexamethasone as prophylaxis for postoperative nausea vomiting during laparoscopic surgeries
Background: In laparoscopic surgeries, insufflation with carbon dioxide triggers vagal afferents on the bowel and peritoneum which induces emesis by activating the vomiting center. It is hypothesized that combined antiemetics with different sites of activity would be more effective than one drug alone for the prophylaxis against PONV. So, the present study was planned to compare the efficacy of granisetron, dexamethasone and combination of granisetron with dexamethasone to prevent PONV.Methods: This randomized prospective double-blind study was performed on 120 patients, aged between 18 and 58 years of ASA physical status I and II of either sex undergoing laparoscopic surgeries under general anesthesia. Patients were randomized in three groups, group I (granisetrone 2 mg I.V.), group II (dexamethasone) 8 mg I.V., group III (granisetrone+dexamethasone) 2 mg+8 mg I.V. with 40 patients in each group. Complete response, incidence of nausea, vomiting, and rescue antiemetic were recorded at specified intervals.Results: A complete response (defined as no PONV and no need for another rescue antiemetic) was achieved in 75% of the patients given granisetron, 70% in dexamethasone and in 92.5% of the patients given granisetron plus dexamethasone (P <0.05). The overall cumulative incidences (0-24 hours) of PONV were 10 (25%) in the granisetron, 12 (30%) in the dexamethasone and 3 (7.5%) in the combination group. No difference in adverse events were observed in any of the groups.Conclusions: The prophylactic therapy of granisetron 2 mg plus dexamethasone 8 mg just before induction of anaesthesia is significantly effective in prevention of PONV in patients undergoing laparoscopic surgeries
Properties of generalized univariate hypergeometric functions
Based on Spiridonov's analysis of elliptic generalizations of the Gauss
hypergeometric function, we develop a common framework for 7-parameter families
of generalized elliptic, hyperbolic and trigonometric univariate hypergeometric
functions. In each case we derive the symmetries of the generalized
hypergeometric function under the Weyl group of type E_7 (elliptic, hyperbolic)
and of type E_6 (trigonometric) using the appropriate versions of the
Nassrallah-Rahman beta integral, and we derive contiguous relations using
fundamental addition formulas for theta and sine functions. The top level
degenerations of the hyperbolic and trigonometric hypergeometric functions are
identified with Ruijsenaars' relativistic hypergeometric function and the
Askey-Wilson function, respectively. We show that the degeneration process
yields various new and known identities for hyperbolic and trigonometric
special functions. We also describe an intimate connection between the
hyperbolic and trigonometric theory, which yields an expression of the
hyperbolic hypergeometric function as an explicit bilinear sum in trigonometric
hypergeometric functions.Comment: 46 page
Can the "brick wall" model present the same results in different coordinate representations?
By using the 't Hooft's "brick wall" model and the Pauli-Villars
regularization scheme we calculate the statistical-mechanical entropies arising
from the quantum scalar field in different coordinate settings, such as the
Painlev\'{e} and Lemaitre coordinates. At first glance, it seems that the
entropies would be different from that in the standard Schwarzschild coordinate
since the metrics in both the Painlev\'{e} and Lemaitre coordinates do not
possess the singularity at the event horizon as that in the Schwarzschild-like
coordinate. However, after an exact calculation we find that, up to the
subleading correction, the statistical-mechanical entropies in these
coordinates are equivalent to that in the Schwarzschild-like coordinate. The
result is not only valid for black holes and de Sitter spaces, but also for the
case that the quantum field exerts back reaction on the gravitational field
provided that the back reaction does not alter the symmetry of the spacetime.Comment: 8 pages, Phys. Rev. D in pres
Algebraic approach to quantum black holes: logarithmic corrections to black hole entropy
The algebraic approach to black hole quantization requires the horizon area
eigenvalues to be equally spaced. As shown previously, for a neutral
non-rotating black hole, such eigenvalues must be -fold degenerate if
one constructs the black hole stationary states by means of a pair of creation
operators subject to a specific algebra. We show that the algebra of these two
building blocks exhibits symmetry, where the area
operator generates the U(1) symmetry. The three generators of the SU(2)
symmetry represent a {\it global} quantum number (hyperspin) of the black hole,
and we show that this hyperspin must be zero. As a result, the degeneracy of
the -th area eigenvalue is reduced to for large , and
therefore, the logarithmic correction term should be added to the
Bekenstein-Hawking entropy. We also provide a heuristic approach explaining
this result, and an evidence for the existence of {\it two} building blocks.Comment: 15 pages, Revtex, to appear in Phys. Rev.
Damped Lyα absorbers in star-forming galaxies at z < 0.15 detected with the Hubble Space Telescope and implications for galactic evolution
Interstellar matter and star formationGalaxie
Atom focusing by far-detuned and resonant standing wave fields: Thin lens regime
The focusing of atoms interacting with both far-detuned and resonant standing
wave fields in the thin lens regime is considered. The thin lens approximation
is discussed quantitatively from a quantum perspective. Exact quantum
expressions for the Fourier components of the density (that include all
spherical aberration) are used to study the focusing numerically. The following
lens parameters and density profiles are calculated as functions of the pulsed
field area : the position of the focal plane, peak atomic density,
atomic density pattern at the focus, focal spot size, depth of focus, and
background density. The lens parameters are compared to asymptotic, analytical
results derived from a scalar diffraction theory for which spherical aberration
is small but non-negligible (). Within the diffraction theory
analytical expressions show that the focused atoms in the far detuned case have
an approximately constant background density
while the peak density behaves as , the focal distance or
time as , the focal spot size as
, and the depth of focus as .
Focusing by the resonant standing wave field leads to a new effect, a Rabi-
like oscillation of the atom density. For the far-detuned lens, chromatic
aberration is studied with the exact Fourier results. Similarly, the
degradation of the focus that results from angular divergence in beams or
thermal velocity distributions in traps is studied quantitatively with the
exact Fourier method and understood analytically using the asymptotic results.
Overall, we show that strong thin lens focusing is possible with modest laser
powers and with currently achievable atomic beam characteristics.Comment: 21 pages, 11 figure
Horizons, Constraints, and Black Hole Entropy
Black hole entropy appears to be ``universal''--many independent
calculations, involving models with very different microscopic degrees of
freedom, all yield the same density of states. I discuss the proposal that this
universality comes from the behavior of the underlying symmetries of the
classical theory. To impose the condition that a black hole be present, we must
partially break the classical symmetries of general relativity, and the
resulting Goldstone boson-like degrees of freedom may account for the
Bekenstein-Hawking entropy. In particular, I demonstrate that the imposition of
a ``stretched horizon'' constraint modifies the algebra of symmetries at the
horizon, allowing the use of standard conformal field theory techniques to
determine the asymptotic density of states. The results reproduce the
Bekenstein-Hawking entropy without any need for detailed assumptions about the
microscopic theory.Comment: 16 pages, talk given at the "Peyresq Physics 10 Meeting on Micro and
Macro structures of spacetime
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