Fuente de tensiones reguladas permanentes

Se describe un sistema desarrollado para mantener en funcionamiento continuo tres relojes de precisión (uno atómico y dos de cuarzo) existentes en el Observatorio Astronómico "Felix Aguilar". Todas las tensiones de salida son reguladas electrónicamente, por lo que la tensión de trabajo de los relojes es prácticamente independiente de la tensión de las baterías. El sistema es totalmente automático y protegido contra sobrecargas y cortocircuitos. Se dispuso en un único gabinete la electrónica y las baterías (28 elementos Nife KAP3 de NiCd). El sistema tiene una autonomía real de seis horas de funcionamiento, alimentando los tres relojes fundamentales de la sala de relojes del O.A.F.A.Asociación Argentina de Astronomí

Sistema de distribución de horas: media y sidérea

Se describe un sistema desarrollado para la distribución de las dos horas de interés en el Observatorio Astronómico "Félix Aguilar" (OAFA); la hora media (hora civil) y la hora sidérea. El sistema está compuesto por: a) Un transmisor al que se puede colocar en hora en forma muy sencilla. La marcha de ambas horas es impuesta por los pulsos de segundo de su respectivo patrón de cuarzo (exterior a la unidad transmisora), b) un conjunto de receptores que muestran en un sistema de 12 dígitos luminosos ambas horas, en las cúpulas de observación y cualquier otro lugar de interés (los receptores pueden ser utilizados como unidades portátiles). El vínculo entre el transmisor y los receptores es un simple cable (de dos conductores) por el que se envía la información completa de las horas (6 dígitos por c/u) y la energía necesaria para alimentar los receptores. El sistema funciona con el auxilio de una batería de 12 V que garantiza el funcionamiento continuo.Asociación Argentina de Astronomí

Sedimentologia y Mineralogia de Playas de la Peninsula Valdes y el Golfo Nuevo (Chubut - Argentina)

Beach sediments of the area under study have the following textural characteristics: 59% correspond to fine sands; in lower proportion we can find medium and coarse sands; 40% are gravel and sandy gravel; 1% include the politic fraction. Log-probabilistic curves show a general normal behavior in textural distribution. The predominant sorting is moderate indicating an intermediate maturity degree. Mineralogical characteristics are: minerals present belong to the “pampeano-patagónica” association; high concentrations of glass and garnet have been observed in some areas and this can be attributed to local dynamic conditions; using the grouping statistical analysis three groups were established and their characteristics would indicate a distributive tendency related to energy conditions of each environment; the gulfs dynamical behavior would depends on the coastal topography and on wind influences over littoral drift

Factors affecting milking speed in Murciano-Granadina breed goats

[EN] Milk flow during the first minute of milking was analyzed using data from 1,132 Murciano-Granadina breed goats belonging to 17 herds. During the individual lactations, 2 test days were scheduled for recording several milk flow traits, total milk, milk composition (fat and protein percentages), and somatic cell count. Average lag time from teatcup attachment to arrival of milk at the milk claw (TO) was 4.9 s and at the milk meter (T1) was 15.8 s. Average milk flow after 30 s (MF0.5) was 0.29 kg/30 s (0 to 1.1 kg/30 s) and milk flow at 60 s or milking speed (MF1) was 0.67 kg/min (0.1 to 2.1 kg/min). Repeatabilities of T0, T1, MF0.5, and MF1 were 0.45, 0.58, 0.62, and 0.68, respectively. The MF1 showed high phenotypic correlation with T1 (-0.63) and MF0.5 (0.90), medium values with T0 (-0.42) and total milk (0.22), and very low values (-0.04 to -0.12) with fat, protein, and somatic cell count. We found no differences between flows during the first 3 lactations, with a reduction as the lactation number increased. Months in milk since parturition affected MF1, being highest in the first 3 mo (0.67-0.71 kg/ min) and decreasing until the end of lactation (0.58 kg/ min). The effect of herd-test day was significant for all traits. Inclusion of all these effects for the analysis of milk flow traits is considered necessary.This work was funded by the Spanish INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain) through European FEDER funds (the project RTA2010 0132 led by E. A. Gomez and the scholarship FPI-INIA2011 042 attained by E. Blasco).Blasco, E.; Gómez, E.; Vicente Martín, C.; Vidal, G.; Peris Ribera, CJ. (2016). Factors affecting milking speed in Murciano-Granadina breed goats. Journal of Dairy Science. 99(12):10102-10108. https://doi.org/10.3168/jds.2016-10869S1010210108991

Overproduction of cosmic superstrings

We show that the naive application of the Kibble mechanism seriously underestimates the initial density of cosmic superstrings that can be formed during the annihilation of D-branes in the early universe, as in models of brane-antibrane inflation. We study the formation of defects in effective field theories of the string theory tachyon both analytically, by solving the equation of motion of the tachyon field near the core of the defect, and numerically, by evolving the tachyon field on a lattice. We find that defects generically form with correlation lengths of order M_s^{-1} rather than H^{-1}. Hence, defects localized in extra dimensions may be formed at the end of inflation. This implies that brane-antibrane inflation models where inflation is driven by branes which wrap the compact manifold may have problems with overclosure by cosmological relics, such as domain walls and monopoles.Comment: 31 pages, 16 figures, JHEP style; References added; Improved discussion of initial condition

Spinflation from Geometric Tachyon

We study the assisted inflation scenario from the rolling of $N$ BPS D3-brane into the NS5-branes, on a transverse geometry of $R^3 \times S^1$, coupled to four dimensional gravity. We assume that the branes are distributed along $S^1$ and the probe D3-branes spin along $R^3$ plane. Qualitatively this process is similar to that of N-tachyon assisted inflation on unstable D-branes. We further study the spinflation scenario numerically and analyze its effect.Comment: 18pages, 9 figures, added clarifications, to appear in JHE

Requirements on collider data to match the precision of WMAP on supersymmetric dark matter

If future colliders discover supersymmetric particles and probe their properties, one could predict the dark matter density of the Universe and would constrain cosmology with the help of precision data provided by WMAP and PLANCK. We investigate how well the relic density can be predicted in minimal supergravity (mSUGRA), with and without the assumption of mSUGRA when analysing data. We determine the parameters to which the relic density is most sensitive, and quantify the collider accuracy needed. Theoretical errors in the prediction are investigated in some detail.Comment: 42 pages, 16 figures. v2 incorporates referee's comments: minor corrections/clarifications with additional figures to show regions of m12-m0 plane considere

Supersymmetric Dark Matter and Yukawa Unification

An analysis of supersymmetric dark matter under the Yukawa unification constraint is given. The analysis utilizes the recently discovered region of the parameter space of models with gaugino mass nonuniversalities where large negative supersymmetric corrections to the b quark mass appear to allow $b-\tau$ unification for a positive $\mu$ sign consistent with the $b\to s+\gamma$ and $g_{\mu}-2$ constraints. In the present analysis we use the revised theoretical determination of $a_{\mu}^{SM}$ ($a_{\mu}= (g_{\mu}-2)/2$) in computing the difference $a_{\mu}^{exp}-a_{\mu}^{SM}$ which takes account of a reevaluation of the light by light contribution which has a positive sign. The analysis shows that the region of the parameter space with nonuniversalities of the gaugino masses which allows for unification of Yukawa couplings also contains regions which allow satisfaction of the relic density constraint. Specifically we find that the lightest neutralino mass consistent with the relic density constraint, $b\tau$ unification for SU(5) and $b-t-\tau$ unification for SO(10) in addition to other constraints lies in the region below 80 GeV. An analysis of the maximum and the minimum neutralino-proton scalar cross section for the allowed parameter space including the effect of a new determination of the pion-nucleon sigma term is also given. It is found that the full parameter space for this class of models can be explored in the next generation of proposed dark matter detectors.Comment: 28 pages,nLatex including 5 fig

Caustic Formation in Tachyon Effective Field Theories

Certain configurations of D-branes, for example wrong dimensional branes or the brane-antibrane system, are unstable to decay. This instability is described by the appearance of a tachyonic mode in the spectrum of open strings ending on the brane(s). The decay of these unstable systems is described by the rolling of the tachyon field from the unstable maximum to the minimum of its potential. We analytically study the dynamics of the inhomogeneous tachyon field as it rolls towards the true vacuum of the theory in the context of several different tachyon effective actions. We find that the vacuum dynamics of these theories is remarkably similar and in particular we show that in all cases the tachyon field forms caustics where second and higher derivatives of the field blow up. The formation of caustics signals a pathology in the evolution since each of the effective actions considered is not reliable in the vicinity of a caustic. We speculate that the formation of caustics is an artifact of truncating the tachyon action, which should contain all orders of derivatives acting on the field, to a finite number of derivatives. Finally, we consider inhomogeneous solutions in p-adic string theory, a toy model of the bosonic tachyon which contains derivatives of all orders acting on the field. For a large class of initial conditions we conclusively show that the evolution is well behaved in this case. It is unclear if these caustics are a genuine prediction of string theory or not.Comment: 23 pages, 5 figures; accepted for publication in JHEP. Revised derivation of eikonal equation for the DBI action. Added comments concerning the relationship between p-adic string theory and tachyon matter. Added second example of inhomogeneous evolution in p-adic string theory. Misleading statements concerning caustic-free evolution removed, references adde

Erratum To: Quality Of Sweat Test (st) Based On The Proportion Of Sweat Sodium (na) And Sweat Chloride (cl) As Diagnostic Parameter Of Cystic Fibrosis: Are We On The Right Way?

During production of the original article [1] the Methods section included an incorrect sentence. The following sentence "For the analysis of variables with numerical distribution, Fisher's exact test and one-way analysis of variance were used" should be corrected as "For the analysis of variables with numerical distribution, Student's t-test and one-way analysis of variance were used". © The Author(s).12