2,645 research outputs found
Lorentz-violating effects in the Bose-Einstein condensation of an ideal bosonic gas
We have studied the effects of Lorentz-violation in the Bose-Einstein
condensation (BEC) of an ideal boson gas, by assessing both the nonrelativistic
and ultrarelativistic limits. Our model describes a massive complex scalar
field coupled to a CPT-even and Lorentz-violating background. We irst analyze
the nonrelativistic case, at this level by using experimental data, we obtain
upper-bounds for some LIV parameters. In the sequel, we have constructed the
partition function for the relativistic ideal boson gas which to be able of a
consistent description requires the imposition of severe restrictions on some
LIV coefficients. In both cases, we have demonstrated that the LIV
contributions are contained in an overall factor, which multiplies almost all
thermodynamical properties. An exception is the fraction of the condensed
particles.Comment: 7 pages Latex2e. To be published in Modern Physics Letters
Implementación de un sistema de gestión de personal orientado a la mejora continua de los procesos de producción en una fábrica de alimentos
El manejo de la motivación, involucramiento y participación de las personas dentro de una fábrica o empresa es un tema que suele ser tratado de manera empírica, o en ocasiones simplemente no se tiene en consideración dentro de su organización. Por otro lado, es también evidente que en muchas industrias no existe un sistema estructurado de gestión de mejora y optimización de los recursos y procesos. El presente trabajo ilustra un caso exitoso de implementación en una fábrica de alimentos de un sistema de gestión de personal orientado a la mejora continua de los procesos de producción, en el que se combinó justamente la necesidad de solucionar los dos problemas planteados que existían también en dicha instalación fabril. El objetivo principal trazado fue el de inculcar en las personas la búsqueda continua de mejorar, y que esta manera de actuar resulte en ideas y proyectos presentados e implementados por el propio personal que generen ahorros y mejoras tangibles para la empresa. Como resultado final se consiguieron los ahorros fijados como meta, se consiguió infundir la cultura de mejora continua reflejada en la participación activa del personal, y como logro adicional se tiene un proceso estructurado, sostenible y auto sustentable que puede tener resultados positivos por mucho tiempo
Emergency conflict-related psychosocial interventions in Sierra Leone and Uganda: lessons from Médecins Sans Frontières
Médecins Sans Frontières has been involved in emergency mental health or psychosocial programmes since 1990. In this article the intervention model developed for emergency settings is shared. Psychosocial programmes distinguish two elements. The 'psycho'-component facilitates the reconnection of the affected individual to his environment. The 'socio'-element aims to create an environment that facilitates the individual to re-integrate. The nature of mental health and psychosocial programmes requires a multidisciplinary approach. Emotional support can also be provided by regular medical staff and does not always require a specialist. The years ahead of us are important for the development of psychosocial interventions. Fundamental issues such as programme evaluation need systematic research
Exposure to violence and PTSD symptoms among Somali women
Posttraumatic stress disorder (PTSD) symptoms, exposure to traumatic stressors, and health care utilization were examined in 84 women attending a primary health care clinic in Mogadishu, Somalia. The Somalia-Posttraumatic Diagnostic Scale was used in this active warzone to measure symptoms. Nearly all women reported high levels of confrontations with violence; half described being exposed to a potentially traumatizing event. Nearly one third had significant PTSD symptoms. Compared to those who did not, women who reported exposure to a traumatic stressor reported more confrontations with violence (7.1 vs. 3.3; p < . 001), health complaints (3.8 vs. 2.9; p = .03), and nearly 3 times as much (p = .03) health service utilization. A potentially traumatizing event was found to be a simplified proxy for assessing mental health distress in women attending a primary health care facility in highly insecure, unpredictable, resource-limited settings
Quantum matter wave dynamics with moving mirrors
When a stationary reflecting wall acting as a perfect mirror for an atomic
beam with well defined incident velocity is suddenly removed, the density
profile develops during the time evolution an oscillatory pattern known as
diffraction in time. The interference fringes are suppressed or their
visibility is diminished by several effects such as averaging over a
distribution of incident velocities, apodization of the aperture function,
atom-atom interactions, imperfect reflection or environmental noise. However,
when the mirror moves with finite velocity along the direction of propagation
of the beam, the visibility of the fringes is enhanced. For mirror velocities
below beam velocity, as used for slowing down the beam, the matter wave splits
into three regions separated by space-time points with classical analogues. For
mirror velocities above beam velocity a visibility enhancement occurs without a
classical counterpart. When the velocity of the beam approaches that of the
mirror the density oscillations rise by a factor 1.8 over the stationary value.Comment: 5.2 pages, 6 figure
Qualitative Assessment of General Aviation Pilots’ Perceptions of Preflight Weather Briefings
Prior to departing on a flight, General Aviation pilots complete a pre-flight planning process to ensure the safety of their flight. One aspect of the pre-flight planning process is obtaining a briefing on the weather conditions that the pilot might encounter along their flight route. Traditionally pilots have utilized a phone-in service run by Flight Services to aid in their assessment of weather conditions. However, research indicates that pilots are increasingly reliant on conducting self- briefing using online resources. The purpose of this study is to determine pilot perceptions of obtaining a phone-in brief in comparison to self-briefing
Міфологізм у символістській прозі Клима Поліщука
The particularities of mythology in symbolist prose by Klym Polishchuk are explained in the article. There are two time planes of plot evolvement in fantastic stories by Klym PolishchukG past and present. Fantastic events in the past have continuation in
Influence of Camponotus blandus (Formicinae) and flower buds on the occurrence of Parrhasius polibetes (Lepidoptera: Lycaenidae) in Banisteriopsis malifolia (Malpighiaceae)
In the Brazilian savanna, myrmecophilous lycaenids are often found in many shrubs feeding on plant reproductive structures while are tended by ants, but only recently the role of both ants and food on the occurrence of lycaenids have received attention. In this study, we investigated the influence of Camponotus blandus (Formicinae) and flower bud abundance on the occurrence of Parrhasius polibetes, a florivorous lycaenid species that occurs in Banisteriopsis malifolia(Malpighiaceae). We also examined to what extent larval florivory was deleterious to plant reproductive outputs. Ant-exclusion experiments revealed that most P. polibetes individuals were found on branches with free C. blandus access. Nonetheless, the occurrence of larvae was not related to the abundance of these ants and flower buds, indicating that the presence, rather than the abundance of mutualistic ants and food, influenced the occurrence of P. polibetes. Larvae were attended by C. blandus, which antennated frequently the dorsal nectary organ of larvae. Larval florivory was not deleterious to the plant. Banisteriopsis malifolia produces thousands of buds simultaneously and larvae feed only on a small portion of flower buds. The occurrence of P. polibetes inB. malifolia is advantageous for the larvae, since this plant supports mutualistic ants and plenty of food resources
Quasiblack holes with pressure: relativistic charged spheres as the frozen stars
In general relativity coupled to Maxwell's electromagnetism and charged
matter, when the gravitational potential and the electric potential field
obey a relation of the form , where , and are arbitrary constants, and (the
speed of light and Newton's constant are put to one), a class of very
interesting electrically charged systems with pressure arises. We call the
relation above between and , the Weyl-Guilfoyle relation, and it
generalizes the usual Weyl relation, for which . For both, Weyl and
Weyl-Guilfoyle relations, the electrically charged fluid, if present, may have
nonzero pressure. Fluids obeying the Weyl-Guilfoyle relation are called
Weyl-Guilfoyle fluids. These fluids, under the assumption of spherical
symmetry, exhibit solutions which can be matched to the electrovacuum
Reissner-Nordstr\"om spacetime to yield global asymptotically flat cold charged
stars. We show that a particular spherically symmetric class of stars found by
Guilfoyle has a well-behaved limit which corresponds to an extremal
Reissner-Nordstr\"om quasiblack hole with pressure, i.e., in which the fluid
inside the quasihorizon has electric charge and pressure, and the geometry
outside the quasihorizon is given by the extremal Reissner-Nordstr\"om metric.
The main physical properties of such charged stars and quasiblack holes with
pressure are analyzed. An important development provided by these stars and
quasiblack holes is that without pressure the solutions, Majumdar-Papapetrou
solutions, are unstable to kinetic perturbations. Solutions with pressure may
avoid this instability. If stable, these cold quasiblack holes with pressure,
i.e., these compact relativistic charged spheres, are really frozen stars.Comment: 16 pages, 8 figures; minor change
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