Ground-state properties of bosons in three- and two-dimensional traps

We study trapped systems of bosons at zero temperature in three and two dimensions. Conditions are fulfilled for the application of Gross-Pitaevskii theory with a positive scattering length. Series expansions for ground-state properties are obtained in both the noninteracting and the strong-coupling (Thomas-Fermi) limits. From these expansions, analytic estimates are presented in the form of two-point Pad\'e approximants. We explicitly show the approximants for the total energy per particle and the chemical potential.Comment: LaTeX, 4 pages, 3 ps figure

Magnetic Collapse of a Neutron Gas: No Magnetar Formation

A degenerate neutron gas in equilibrium with a background of electrons and protons in a magnetic field exerts its pressure anisotropically, having a smaller value perpendicular than along the magnetic field. For critical fields the magnetic pressure may produce the vanishing of the equatorial pressure of the neutron gas, and the outcome could be a transverse collapse of the star. This fixes a limit to the fields to be observable in stable pulsars as a function of their density. The final structure left over after the implosion might be a mixed phase of nucleons and meson ($\pi^{\pm,0},\kappa^{\pm,0}$) condensate (a strange star also likely) or a black string, but no magnetar at all.Comment: 5 pages, 1 latex file, 1 encapsulated figure. Submitted to Physical Review Letters (24/11/2000

On the Collective Mode Spectrum for Composite Fermions at 1/3 Filling Factor

The collective mode spectrum of the composite fermion state 1/3 filling factor is evaluated. At zero momentum, the result coincides with the cyclotron energy at the external magnetic field value, and not at the effective magnetic field, in spite of the fact that only the former enters in the equations, thus, the Kohn theorem is satisfied. Unexpectedly, in place of a magneto roton minimum, the collective mode gets a treshold indicating the instability of the mean field composite fermion state under the formation of crystalline structures. However, the question about if if this outcome only appears within the mean field approximation should be further considered.Comment: 17 pages, one figure. Submitted to Int. Jour. Mod. Phys.

Determinants of extramarital sex in the Philippines

Understanding the factors associated with sexual behaviour is critical in slowing the spread of HIV in the Philippines, where sexual transmission accounts for most HIV infections, with the majority from heterosexual activity. Further, unprotected sex is common, as is sex with prostitutes. These factors increase the risks associated with extramarital sex. From an analysis of a nationally representative sample of women, we found that a number of factors were related to women’s reports of their husbands’ sexual activity outside their current relationship: women report that partners who are more educated, have been in the current relationship longer, and who had sex before marriage are more likely to be engaging in sex outside the marriage. Further, men who are older, who are farmers, who live at home, and who have more educated wives, were believed to be less likely to be having extramarital sex

Principios, Normas y Procedimientos de Contabilidad Gubernamental en el Ministerio de la Familia (MiFamilia) del Departamento de Matagalpa durante el primer semestre del año 2010

El Sistema de Contabilidad Gubernamental contiene un Manual de Contabilidad con Principios, Normas y Procedimientos establecidos, de uso obligatorio para todas las Instituciones del Estado, en este caso hemos analizado específicamente la aplicación de éstos en el Ministerio de la Familia del Departamento de Matagalpa durante el I semestre del año 2010. Con el empleo de esta temática nos propusimos determinar el uso correcto de los recursos financieros, según el Presupuesto destinado por el Gobierno de la República de Nicaragua, tomando como base la aplicación de Principios, Normas y Procedimientos para la fortaleza en el registro de las operaciones y la presentación adecuada de la Información Contable. Al abordar este tema y adaptarlo al Ministerio de la Familia nos percatamos de su importancia porque a través de la aplicación de Principios, Normas y Procedimientos de Contabilidad Gubernamental este Ente Público contable consigue realizar sus actividades asignadas de forma satisfactoria, así como también presentar a su autoridad superior la información contable de forma clara, legal y confiable lo que conlleva a esta institución trabajar de forma eficiente al servicio del público. A través del estudio realizado en el Ministerio de la Familia hemos determinado que éste cumple con la aplicación de estos principios y normas para la presentación de una información legal y clara como lo mandata el Sistema de contabilidad Gubernamental por lo tanto es de vital importancia su acatamiento para que el Ministerio continúe funcionando como parte del Sector Públic

Compact Stars and Magnetized CFL Matter

The stability of the color flavor locked phase in the presence of a strong magnetic field is investigated within the phenomenological MIT bag model. It is found that the minimum value of the energy per baryon in a color flavor locked state at vanishing pressure is lower than the corresponding one for unpaired magnetized strange quark matter and, as the magnetic field increases, the energy per baryon decreases. This implies that magnetized color flavor locked matter is more stable and could become the ground state inside neutron stars. The anisotropy of the pressures is discussed. The mass-radius relation for such stars is also studied

Stability Conditions and the Single Mode Approximation in FQHE

A thermodynamic stability criterion for the spontaneous breaking of the translation invariance of many particle systems is derived. It simply requires the positive character of the wavevector dependent dielectric function as generalising the same condition for macroscopic dielectric constants. Its application to the Single Mode Approximation (SMA) for the description of the collective modes of the filling factor 1/m Laughlin states is considered. The results indicate that the stability condition is violated by the SMA for all the relevant states m=3,5,7,9 in a wavevector neighborhood of the magneto-roton minima. These conclusions are in qualitative agreement with similar results obtained from the solution of the Bethe-Salpeter equation at 1/3 filling factor for both composite fermions and phenomenologically described electrons in the Laughlin state.Comment: 14 pages, two figures, the spelling and acknowledgments were correcte

Magnetic Field and Temperature Effects on Strangelets

The main properties of magnetized strangelets, namely, their energy per baryon, radius and electric charge, are studied in the unpaired strange quark matter phase. Temperature effects are taken into account in order to study their stability compared to the (56)Fe isotope and non-magnetized strangelets within the framework of the MIT bag model. It is concluded that the presence of a magnetic field tends to stabilize more the strangelets, even when temperature is considered. We find that the electric charge is modified in the presence of the magnetic field, leading to higher charge values for magnetized strangelets, when compared to the non-magnetized case

Mixed monolayer of DPPC and lysine-based cationic surfactants: An investigation into the antimicrobial activity

In this paper, we report studies which aim to elucidate the mechanisms involved in the antimicrobial activity of three cationic lysine-based surfactants: LLM, LALM, and C6 (LL)2. To this end, a simple membrane model (i.e., 1,2-dipalmitoyl-sn-phosphatidylcholine, DPPC) was used to explore the monolayer properties at the air/liquid interface. Compression π-A isotherms of mixtures of DPPC/lysine surfactants at different pH showed an expansion of the DPPC monolayer, suggesting cationic lysine surfactant/DPPC interactions, which strongly depend on surfactant structure and hydrophobic interactions. Antimicrobial activity of the three surfactants has also been assessed with transmission electron microscopy, observing the effects on Staphylococcus aureus and Escherichia coli. The three surfactants caused various kinds of damage to the bacteria tested, such as structural alterations, leakage of internal material, and cell destruction.Authors have been supported by the CICYT Spanish Research Agency under the projects CTQ2009-14151-C02-01 and CTQ2010-14897 and by AGAUR Research Agency of the Generalitat de Catalunya under the project 2009 SRG 246Peer reviewe