Astroparticle Physics at Eastern Colombia

We present the emerging panorama of Astroparticle Physics at Eastern Colombia, and describe several ongoing projects, most of them related to the Latin American Giant Observatory (LAGO) Project. This research work is carried out at the Grupo de Investigaciones en Relatividad y Gravitaci\'on of Universidad Industrial de Santander.Comment: 19 pages, 8 figure

Empirical testing of Tsallis' Thermodynamics as a model for dark matter halos

We study a dark matter halo model from two points of view: the ``stellar polytrope'' (SP) model coming from Tsallis' thermodynamics, and the one coming from the Navarro-Frenk-White (NFW) paradigm. We make an appropriate comparison between both halo models and analyzing the relations between the global physical parameters of observed galactic disks, coming from a sample of actual galaxies, with the ones of the unobserved dark matter halos, we conclude that the SP model is favored over the NFW model in such a comparison.Comment: 5 pages, 1 figure, To appear in the Proceedings of X Mexican Workshop on Particles and Fields, Morelia Michoac\'an, M\'exico, November 7-12, 200

Entropy considerations in constraining the mSUGRA parameter space

We explore the use of two criteria to constraint the allowed parameter space in mSUGRA models. Both criteria are based in the calculation of the present density of neutralinos as dark matter in the Universe. The first one is the usual ``abundance'' criterion which is used to calculate the relic density after the ``freeze-out'' era. To compute the relic density we used the numerical public code micrOMEGAs. The second criterion applies the microcanonical definition of entropy to a weakly interacting and self-gravitating gas evaluating then the change in the entropy per particle of this gas between the ``freeze-out'' era and present day virialized structures. An ``entropy-consistency'' criterion emerges by comparing theoretical and empirical estimates of this entropy. The main objective of our work is to determine for which regions of the parameter space in the mSUGRA model are both criteria consistent with the 2$\sigma$ bounds according to WMAP for the relic density: $0.0945<\Omega_{CDM}h^2<0.1287$. As a first result, we found that for $A_0=0$, sgn$\mu=+$, small values of tan$\beta$ are not favored; only for tan$\beta\simeq50$ are both criteria significantly consistent.Comment: 5 pages, 1 figure. To appear in the Proceedings of X Mexican Workshop on Particles and Fields, Morelia Michoac\'an, M\'exico, November 7-12, 200

Fascitis necrotizante de extremidad superior: a propósito de un caso

Los autores presentan un caso de fascitis necrotizante en miembro superior causada por la combinación de bacterias estreptococo microaerofílico y estafilococo aureus. El paciente ha sobrevivido con una pérdida orgánica mínima (amputación del quinto dedo) y una recuperación funcional completa. Se destaca el papel de la antibioterapia precoz.The authors report a case of necrotizing fascitis of the upper limb, produced by a microaerophilic streptococcus and staphilococcus aureus. The only organic sequelae for the patient was amputation of the little finger with a complete recovery of the functional capacity. The role of the early institution of high dose antibiotic therapy is emphasized

Fracturas del macizo trocantéreo. Estudio comparativo Ender-DHS: revision de 114 casos

Se presenta un estudio retrospectivo de 114 fracturas pertrocantéreas tratadas con enclavado elástico de Ender (71) y tornillo placa deslizante, DHS (43). Se efectuó un estudio estadístico descriptivo-comparativo entre los 2 grupos de pacientes según la técnica quirúrgica empleada. Se constató un mayor índice de estabilidad usando el DHS (81%), frente al 6 1 % del otro grupo. La tasa de complicaciones fue del 16% y 55% respectivamente. Los resultados clínicos fueron mejores en los enfermos tratados con DHS, fundamentalmente en cuanto a la deambulación que se consiguió en el 98% (Ender 75%), ausencia de dolor y movilidad conservada. Los autores piensan que la estabilidad preoperatoria no influye en la solidez del montaje usando el DHS, pero con la técnica de Ender ésta disminuye en las fracturas inestables; por ello, la técnica de Ender estaría solamente indicada en el tratamiento de fracturas estables en pacientes de edad avanzada o con mal estado general, aunque en clara competencia con el DHS.A retrospective study of 114 intertrochanteric fractures operated on either with Ender's rods (71) or dynamic hip screws, DHS (43) is presented. A statistical descriptive-comparative study between the 2 groups was attempted. There was a greater index of stability using the DHS (82%) than Ender's rods (61%). The rate of complications was 16% and 55% respectively. The clinical outcome was better in cases treated with DHS, specially for walking ability, which was regained in the 98% of cases (Ender 75%), painless and preserved mobility. The authors think that the stability before operation do not influence the solidity of the assembly using the DHS device. On the contrary, with the Ender's technique the fixation is no satisfactory in unstables fractures. Ender's rods would only be suitable for treatment of stable fractures in older patient or with serious associated diseases, although in clear competition with the DHS

Single-Bud Expression Analysis of Bud Dormancy Factors in Peach

Transcriptomic and gene expression analysis have greatly facilitated the identification and characterization of transcriptional regulatory factors and effectors involved in dormancy progression and other physiological processes orchestrated during bud development in peach and other temperate fruit species. Gene expression measurements are most usually based on average values from several or many individual buds. We have performed single-bud gene analysis in flower buds of peach across dormancy release using amplicons from the master regulatory DORMANCY-ASSOCIATED MADS-BOX (DAM) factors, several jasmonic acid biosynthetic genes, other genes related to flowering development, cell growth resumption, and abiotic stress tolerance. This analysis provides a close view on gene-specific, single-bud variability throughout the developmental shift from dormant to dormancy-released stages, contributing to the characterization of putative co-expression modules and other regulatory aspects in this particular tissue

Sensory determinants of behavioral dynamics in Drosophila thermotaxis

Complex animal behaviors are built from dynamical relationships between sensory inputs, neuronal activity, and motor outputs in patterns with strategic value. Connecting these patterns illuminates how nervous systems compute behavior. Here, we study Drosophila larva navigation up temperature gradients toward preferred temperatures (positive thermotaxis). By tracking the movements of animals responding to fixed spatial temperature gradients or random temperature fluctuations, we calculate the sensitivity and dynamics of the conversion of thermosensory inputs into motor responses. We discover three thermosensory neurons in each dorsal organ ganglion (DOG) that are required for positive thermotaxis. Random optogenetic stimulation of the DOG thermosensory neurons evokes behavioral patterns that mimic the response to temperature variations. In vivo calcium and voltage imaging reveals that the DOG thermosensory neurons exhibit activity patterns with sensitivity and dynamics matched to the behavioral response. Temporal processing of temperature variations carried out by the DOG thermosensory neurons emerges in distinct motor responses during thermotaxis