139 research outputs found
A Generalized Uhlenbeck and Beth Formula for the Third Cluster Coefficient
Relatively recently (A. Amaya-Tapia, S. Y. Larsen and M. Lassaut. Ann. Phys.,
vol. 306 (2011) 406), we presented a formula for the evaluation of the third
Bose fugacity coefficient - leading to the third virial coefficient - in terms
of three-body eigenphase shifts, for particles subject to repulsive forces. An
analytical calculation for a 1-dim. model, for which the result is known,
confirmed the validity of this approach. We now extend the formalism to
particles with attractive forces, and therefore must allow for the possibility
that the particles have bound states. We thus obtain a true generalization of
the famous formula of Uhlenbeck and Beth (G.E. Uhlenbeck and E. Beth. Physica,
vol. 3 (1936) 729; E. Beth and G.E. Uhlenbeck. ibid, vol.4 (1937) 915) (and of
Gropper (L. Gropper. Phys. Rev. vol. 50 (1936) 963; ibid vol. 51 (1937) 1108))
for the second virial. We illustrate our formalism by a calculation, in an
adiabatic approximation, of the third cluster in one dimension, using McGuire's
model as in our previous paper, but with attractive forces. The inclusion of
three-body bound states is trivial; taking into account states having
asymptotically two particles bound, and one free, is not.Comment: 38 pages, 6 figure
Third Bose Fugacity Coefficient in One Dimension, as a Function of Asymptotic Quantities
In one of the very few exact quantum mechanical calculations of fugacity
coefficients, Dodd and Gibbs (\textit{J. Math.Phys}.,\textbf{15}, 41 (1974))
obtained and for a one dimensional Bose gas, subject to
repulsive delta-function interactions, by direct integration of the wave
functions. For , we have shown (\textit{Mol. Phys}.,\textbf{103}, 1301
(2005)) that Dodd and Gibbs' result can be obtained from a phase shift
formalism, if one also includes the contribution of oscillating terms, usually
contributing only in 1 dimension. Now, we develop an exact expression for
(where is the free particle fugacity coefficient)
in terms of sums and differences of 3-body eigenphase shifts. Further, we show
that if we obtain these eigenphase shifts in a distorted-Born approximation,
then, to first order, we reproduce the leading low temperature behaviour,
obtained from an expansion of the two-fold integral of Dodd and Gibbs. The
contributions of the oscillating terms cancel. The formalism that we propose is
not limited to one dimension, but seeks to provide a general method to obtain
virial coefficients, fugacity coefficients, in terms of asymptotic quantities.
The exact one dimensional results allow us to confirm the validity of our
approach in this domain.Comment: 29 page
Urinary Tract Tuberculosis
Urinary tract tuberculosis (UTTB) is an insidious disease with non-specific constitutional symptoms that are often unrecognized and lead to delayed diagnosis. Advanced UTTB may cause loss of kidney function. In the majority of literature, UTTB is reviewed together with genital tuberculosis because often both sites are involved simultaneously; “Genitourinary tuberculosis” (GUTB) is the most common term used in the literature. However, the term may cause confusion because the clinical presentation and diagnosis approach is very different, and does not always occur simultaneously. UTTB is the term used here as we encountered tuberculosis involvement of urinary tract only. This book chapter is a comprehensive review of the epidemiology, pathophysiology, clinical presentation, diagnosis approach, and current treatment of this disease
Second virial coefficient in one dimension, as a function of asymptotic quantities
A result from Dodd and Gibbs[1] for the second virial coefficient of
particles in 1 dimension, subject to delta-function interactions, has been
obtained by direct integration of the wave functions. It is shown that this
result can be obtained from a phase shift formalism, if one includes the
contribution of oscillating terms. The result is important in work to follow,
for the third virial coefficient, for which a similar formalism is being
developed. We examine a number of fine points in the quantum mechanical
formalisms.Comment: 7 pages, no figures, submitted to Molecular Physic
S-matrix poles and the second virial coefficient
For cutoff potentials, a condition which is not a limitation for the
calculation of physical systems, the S-matrix is meromorphic. We can express it
in terms of its poles, and then calculate the quantum mechanical second virial
coefficient of a neutral gas.
Here, we take another look at this approach, and discuss the feasibility,
attraction and problems of the method. Among concerns are the rate of
convergence of the 'pole' expansion and the physical significance of the
'higher' poles.Comment: 20 pages, 8 tables, submitted to J. Mol. Phy
Integral representation of one dimensional three particle scattering for delta function interactions
The Schr\"{o}dinger equation, in hyperspherical coordinates, is solved in
closed form for a system of three particles on a line, interacting via pair
delta functions. This is for the case of equal masses and potential strengths.
The interactions are replaced by appropriate boundary conditions. This leads
then to requiring the solution of a free-particle Schr\"{o}dinger equation
subject to these boundary conditions. A generalized Kontorovich - Lebedev
transformation is used to write this solution as an integral involving a
product of Bessel functions and pseudo-Sturmian functions. The coefficient of
the product is obtained from a three-term recurrence relation, derived from the
boundary condition. The contours of the Kontorovich-Lebedev representation are
fixed by the asymptotic conditions. The scattering matrix is then derived from
the exact solution of the recurrence relation. The wavefunctions that are
obtained are shown to be equivalent to those derived by McGuire. The method can
clearly be applied to a larger number of particles and hopefully might be
useful for unequal masses and potentials.Comment: 18 pages, 2 figures, to be published in J. Math. Phy
Clima organizacional y desempeño laboral de los colaboradores de la Municipalidad Provincial de Pacasmayo, 2022
La investigación tuvo como objetivo determinar la relación entre el clima
organizacional y el desempeño laboral de los colaboradores de la municipalidad
Provincial de Pacasmayo, 2022; pues se observó que en este organismo público
las relaciones entre los colaboradores presentaban dificultades, asimismo
ocurría en el desempeño de sus labores. La metodología del estudio es de tipo
aplicada, presentando un enfoque cuantitativo, con un diseño no experimental
de corte transversal y descriptiva correlacional, La población estuvo constituida
por 245 colaboradores y se tomó una muestra de 69 colaboradores entre ellos
34 administrativos y 35 estables. Los resultados mostraron una correlación
positiva moderada y significativa entre el clima organizacional y el desempeño
laboral con una Rho =0.670 y Sig. (bilateral)= 0,000. En conclusión, se determinó
que las variables de este estudio están relacionadas directamente de manera
positiva y significativa
- …