7,576 research outputs found
Effects of the second virial coefficient on the adiabatic lapse rate of dry atmospheres
We study the effect of the second virial coefficient on the adiabatic lapse
rate of a dry atmosphere. To this end, we compute the corresponding adiabatic
curves, the internal energy, and the heat capacity, among other thermodynamic
parameters. We apply these results to Earth, Mars, Venus, Titan, and the
exoplanet G1 851d, considering three physically relevant virial coefficients in
each case: the hard-sphere, van der Waals, and the square-well potential. These
examples illustrate under which atmospheric conditions the effect of the second
virial coefficient is relevant. Taking the latter into account yields
corrections towards the experimental values of the lapse rates of Venus and
Titan in some instances.Comment: 12 pages, 8 figures. Comments are welcom
Regulación del operador dominante en las telecomunicaciones en México
regulación, telecomunicaciones, operador dominante, México
Cultural Preservation of Ethnomedicine in Peru
In conjunction with the Minority Health & Health Disparities International Research Training program at San Diego State University, three Linfield students contributed to the ongoing Peru Ethnomedical Project in Trujillo, Peru by: Conducting surveys in two neighborhoods on the edge of the city; Creating a medicinal plant garden in the Chan Chan archaeological site museum.
Surveys conducted in Moche, Trujillo were part of a larger study supervised by anthropologists Douglas Sharon and Thomas Love. The research aims to evaluate the usage of medicinal plants in rural and urban Peruvian communities. Linfield’s contribution focused on the creation of the medicinal garden to serve as a community model and educational program. The overall purpose of the 2015 summer faculty collaborative project was to: Preserve the knowledge of these practices; Analyze the plant properties; Publish the information; Provide the community with a garden that reflects the commonly used plants; Educate new generations; Bring back and apply this knowledge in the Linfield community
Starspots on the fastest rotators in the Beta Pic moving group
Aims: We carried out high-resolution spectroscopy and BV(I)_C photometric
monitoring of the two fastest late-type rotators in the nearby Beta Pictoris
moving group, HD199143 (F7V) and CD-641208 (K7V). The motivation for this work
is to investigate the rotation periods and photospheric spot patterns of these
very young stars, with a longer term view to probing the evolution of rotation
and magnetic activity during the early phases of main-sequence evolution. We
also aim to derive information on key physical parameters, such as rotational
velocity and rotation period. Methods: We applied maximum entropy (ME) and
Tikhonov regularizing (TR) criteria to derive the surface spot map
distributions of the optical modulation observed in HD199143 (F7 V) and
CD-641208 (K7V). We also used cross-correlation techniques to determine stellar
parameters such as radial velocities and rotational velocities. Lomb-Scargle
periodograms were used to obtain the rotational periods from differential
magnitude time series. Results: We find periods and inclinations of 0.356 days
and 21.5deg for HD199143, and 0.355 days and 50.1deg for CD-641208. The spot
maps of HD199143 obtained from the ME and TR methods are very similar, although
the latter gives a smoother distribution of the filling factor. Maps obtained
at two different epochs three weeks apart show a remarkable increase in spot
coverage amounting to ~7% of the surface of the photosphere over a time period
of only ~20 days. The spot maps of CD-641208 from the two methods show good
longitudinal agreement, whereas the latitude range of the spots is extended to
cover the whole visible hemisphere in the TR map. The distributions obtained
from the first light curve of HD199143 show the presence of an extended and
asymmetric active longitude with the maximum filling factor at longitude
~325degree.Comment: Accepted by A&A. 13 pages, 13 figures (4 online included), 5 Table
Respuesta de hipersensibilidad retardada en pacientes candidatos a artroplastia de cadera
Se estudiaron 100 pacientes escogidos de manera aleatoria de entre los candidatos a artroplastia de cadera (47 por fractura subcapital de fémur Garden IV, y 53 por coxartrosis). En el momento del ingresos se determinaron en sangre niveles de albúmina, proteínas totales y hemoglobina; y se midió la respuesta de hipersensibilidad retardada mediante la inoculación de siete antígenos de memoria con un aplicador Multitest® (Mérieux). La lectura de la reacción de induración se realizó a las 48 horas. Los pacientes fueron clasificados en: normoérgicos (+) a dos o más antígenos) y anérgicos (una o ninguna respuesta (+). La población normoérgica representó el 61% de los pacientes, con una edad 12,5 años menor que la población anérgica (p<0,001). Los pacientes normoérgicos presentaron cifras significativamente más altas de hemoglobina (p<0,001), proteínas totales (p<0,05) y albúmina (p<0,001). La situación de anergia fue más frecuente en el grupo de mujeres (29/57) frente al de hombres (10/43; p<0,001), y en el grupo de fracturas subcapitales (31/47) que en el de coxartrosis (8/53) (p<0,001). No se hallaron relaciones estadísticamente significativas entre los distintos parámetros estudiados y la aparición de infección en el postoperatorio. Las diferencias aparecidas reflejan alteraciones en la respuesta inmunológica que, sin embargo, no resultan pronósticas frente a la aparición de infección en nuestra serie.One hundred candidates for hip arthroplasty were chosen at random (47 Garden IV femoral neck fractures, and 53 osteoarthrosis). Before surgery, serum albumin, total proteins and haemoglobin were determined in peripheral blood. All patients were skin tested with seven memory antigens (Multitest®, Mérieux) in order to measure the delayed hypersensitivity response. The diameter of the resulting induration was measured 48 hours after injection. Patients were classified as reactive if they responded to one antigen or showed no response. Reactive patients supposed 61% of total, and anergic patients were 12,5 years older (p<0,001). Levels of haemoglobin (p<0,001), total proteins (p<0,05) and albumin (p<0,001) were higher in reactive patients. Anergy was more frequent in women (29/57) than in men (10/43; p<0,001), and in fractures (31/47) than in osteoarthrosis (8/53) (p<0,001). No association between the variables studied and postoperative infection was found. These differences show immunologic alterations. However, they have no prognostic value for postoperative infection in hip arthroplasty patients
Presentation of the paper “Faat – Freelance as a Team”
[EN]This is the presentation of the paper entitled “Faat – Freelance as a Team” in the TEEM
2015 International Conference held in Porto (Portugal) in October 7-9, 2015.
Agile methodologies are reliable engineering and management practices, capable of
helping in the development of quality and successful software in business environments.
However, most of these methodologies are centered on a development team and its
internal communication. Moreover, for simplicity, a single product development is
taken into account with its successive releases. There is another scenario: that of a
single programmer working alone and often in much smaller projects and in several at
the same time. Also in this scenario the client proximity is not as described by the agile
environment ideal. In that case, the priorities and needs change, communication takes
on another meaning and working mechanisms are not always comparable to that of a
team. This paper introduces Faat (Freelance as a Team), a methodology specifically
designed for those professionals. Integrating existing practices to the needs and
possibilities of an individual programmer. However, it has been frequently considered
the possible application of this methodology to small teams and/or other more general
scenarios. This methodology has been tested in the web-based learning applications
A Novel Technology to Segregate Binary Mixtures of Different Density in a Conical Spouted Bed
Relativistic Runge-Lenz vector: from SYM to SO(4) scalar field theory
Starting from SYM and using an appropriate Higgs mechanism we
reconsider the construction of a scalar field theory non-minimally coupled to a
Coulomb potential with a relativistic SO(4) symmetry and check for scalar field
consistency conditions. This scalar field theory can also be obtained from a
relativistic particle Lagrangian with a proper implementation of the
non-minimal coupling. We provide the generalization of the non-relativistic
construction of the Runge-Lenz vector to the relativistic case and show
explicitly that this new vector generates the SO(4) algebra. Using the power of
the SO(4) symmetry, we calculate the relativistic hydrogen atom spectrum. We
provide a generalization of the Kustaanheimo-Stiefel transformation to the
relativistic case and relate our results with the corresponding relativistic
oscillator. Finally, in the light of these results, we reconsider the
calculation of the hydrogen atom spectrum from the cusp anomalous dimension
given in [2].Comment: 17 pages. Enhaced version matching the published JHEP version. Typos
corrected. The argument of concistence at the end of section 2 was correcte
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