Optogenetic elevation of endogenous glucocorticoid level in larval zebrafish

The stress response is a suite of physiological and behavioral processes that help to maintain or reestablish homeostasis. Central to the stress response is the hypothalamic-pituitary-adrenal (HPA) axis, as it releases crucial hormones in response to stress. Glucocorticoids (GCs) are the final effector hormones of the HPA axis, and exert a variety of actions under both basal and stress conditions. Despite their far-reaching importance for health, specific GC effects have been difficult to pin-down due to a lack of methods for selectively manipulating endogenous GC levels. Hence, in order to study stress-induced GC effects, we developed a novel optogenetic approach to selectively manipulate the rise of GCs triggered by stress. Using this approach, we could induce both transient hypercortisolic states and persistent forms of hypercortisolaemia in freely behaving larval zebrafish. Our results also established that transient hypercortisolism leads to enhanced locomotion shortly after stressor exposure. Altogether, we present a highly specific method for manipulating the gain of the stress axis with high temporal accuracy, altering endocrine and behavioral responses to stress as well as basal GC levels. Our study offers a powerful tool for the analysis of rapid (non-genomic) and delayed (genomic) GC effects on brain function and behavior, feedbacks within the stress axis and developmental programming by GCs

Coupling the actuator line method to the high order meteorological les model Meso-NH to study wind farm wakes impacts on local meteorology

Offshore wind energy is now reaching the technological maturity, its capacity is increasing all over the world and this trend is projected to continue for several more years. Given this expectation, a better understanding of the relationship between the presence of wind farms and the atmospheric boundary layer is needed. Turbulent wakes produced by wind turbines can significantly impact the flow dynamics within wind farms and downstream of them. Operating offshore parks have already shown losses on energy production and effects on the local climate. In order to analyse the interactions occurring during these impacts, a new tool has been developed. This numerical tool is a coupling between the Actuator Line Method (ALM) and the open-source, non-hydrostatic mesoscale atmospheric model Meso-NH, based on the Large Eddy Simulation (LES) framework. The coupled Meso-NH + ALM system is first validated by using the experimental data obtained during the New MEXICO experiments. In particular, simulated and experimental loadings along the blades are compared. Then, a simulation of an idealized Horns Rev wind farm is performed using met mast measurements and reanalysis data for the “Horns Rev 1 photo case” as initial conditions. This new coupled system allows the exploration of the impact of wind farms on the lower levels of the atmosphere.Fil: Joulin, P. A.. French Institute of Petroleum Énergies nouvelles; Francia. Centre National de Recherches Météorologiques; FranciaFil: Mayol, María Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaFil: Blondel, F.. French Institute of Petroleum Énergies nouvelles; FranciaFil: Masson, Viviana Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Centre National de Recherches Météorologiques; FranciaFil: Rodier, Q.. Centre National de Recherches Météorologiques; FranciaFil: Lac, C.. Centre National de Recherches Météorologiques; Franci

Simulating Humans as Integral Parts of Spacecraft Missions

The Collaborative-Virtual Environment Simulation Tool (C-VEST) software was developed for use in a NASA project entitled "3-D Interactive Digital Virtual Human." The project is oriented toward the use of a comprehensive suite of advanced software tools in computational simulations for the purposes of human-centered design of spacecraft missions and of the spacecraft, space suits, and other equipment to be used on the missions. The C-VEST software affords an unprecedented suite of capabilities for three-dimensional virtual-environment simulations with plug-in interfaces for physiological data, haptic interfaces, plug-and-play software, realtime control, and/or playback control. Mathematical models of the mechanics of the human body and of the aforementioned equipment are implemented in software and integrated to simulate forces exerted on and by astronauts as they work. The computational results can then support the iterative processes of design, building, and testing in applied systems engineering and integration. The results of the simulations provide guidance for devising measures to counteract effects of microgravity on the human body and for the rapid development of virtual (that is, simulated) prototypes of advanced space suits, cockpits, and robots to enhance the productivity, comfort, and safety of astronauts. The unique ability to implement human-in-the-loop immersion also makes the C-VEST software potentially valuable for use in commercial and academic settings beyond the original space-mission setting

Nucleon-nucleon elastic scattering analysis to 2.5 GeV

A partial-wave analysis of NN elastic scattering data has been completed. This analysis covers an expanded energy range, from threshold to a laboratory kinetic energy of 2.5 GeV, in order to include recent elastic pp scattering data from the EDDA collaboration. The results of both single-energy and energy-dependent analyses are described.Comment: 23 pages of text. Postscript files for the figures are available from ftp://clsaid.phys.vt.edu/pub/said/n

Micro-Capsules in Shear Flow

This paper deals with flow-induced shape transitions of elastic capsules. The state of the art concerning both theory and experiments is briefly reviewed starting with dynamically induced small deformation of initially spherical capsules and the formation of wrinkles on polymerized membranes. Initially non-spherical capsules show tumbling and tank-treading motion in shear flow. Theoretical descriptions of the transition between these two types of motion assuming a fixed shape are at variance with the full capsule dynamics obtained numerically. To resolve the discrepancy, we expand the exact equations of motion for small deformations and find that shape changes play a dominant role. We classify the dynamical phase transitions and obtain numerical and analytical results for the phase boundaries as a function of viscosity contrast, shear and elongational flow rate. We conclude with perspectives on timedependent flow, on shear-induced unbinding from surfaces, on the role of thermal fluctuations, and on applying the concepts of stochastic thermodynamics to these systems.Comment: 34 pages, 15 figure

Cross-species chromosome painting tracks the independent origin of multiple sex chromosomes in two cofamiliar Erythrinidae fishes

<p>Abstract</p> <p>Background</p> <p>The Erythrinidae fish family is characterized by a large variation with respect to diploid chromosome numbers and sex-determining systems among its species, including two multiple X₁X₂Y sex systems in <it>Hoplias malabaricus </it>and <it>Erythrinus erythrinus</it>. At first, the occurrence of a same sex chromosome system within a family suggests that the sex chromosomes are correlated and originated from ancestral XY chromosomes that were either homomorphic or at an early stage of differentiation. To identify the origin and evolution of these X₁X₂Y sex chromosomes, we performed reciprocal cross-species FISH experiments with two sex-chromosome-specific probes designed from microdissected X₁and Y chromosomes of <it>H. malabaricus </it>and <it>E. erythrinus</it>, respectively.</p> <p>Results</p> <p>Our results yield valuable information regarding the origin and evolution of these sex chromosome systems. Our data indicate that these sex chromosomes evolved independently in these two closed related Erythrinidae species. Different autosomes were first converted into a poorly differentiated XY sex pair in each species, and additional chromosomal rearrangements produced both X₁X₂Y sex systems that are currently present.</p> <p>Conclusions</p> <p>Our data provide new insights into the origin and evolution of sex chromosomes, which increases our knowledge about fish sex chromosome evolution.</p

Sobre la calibración de medidores de impacto

En este trabajo los autores proponen una metodología para el tratamiento de la información obtenida a partir de los medidores de impacto, con el fin de dar pautas para la evaluación físico-estadística de la experiencia de lucha antigranizo encarada en la provincia de Mendoza por la Comisión Nacional de investigaciones Espaciales (C.N.I.E.). Se abordan los aspectos teóricos y prácticos de la calibración de los medidores de impacto. Además, se discuten los problemas emergentes de la curva de calibración que relacionan los diámetros reales con los medidos. Mediante experiencias basadas en la caída de esferas de acero, se obtuvo una función lineal entre el tamaño real y el diámetro medido mediante el ajuste por mínimos cuadrados. El diámetro real es mayor que el diámetro medido y se nota la imposibilidad de medir granizos con un diámetro menor de 0,5 cm. Se encontró que la distribución de frecuencias de los tamaños reales del granizo se ajusta mejor a la función gamma.In this paper the authors propose a methodology to treat the information which has been collected from the hailpads aimed to establish some points for the physical-statistical evaluation of the anti-hail experience which is being conducted in the province of Mendoza. Theoretical and empirical aspects related to the hailpads calibration are examined. Besides, the problems resulting from the use of the calibration curve which relates real and measured diameters are discussed. By means of experiences based on fallings of steel balls, it was obtained a linear function real and mesured diameters, by the minimwn square method. The real diameters is always longer than the mesured one, and untill now it is impossible to detect hail diameters less than 0,5 cm. It was found that frequency distribution of real sizes is almost well fitted by the gamma distribution.Asociación Argentina de Geofísicos y Geodesta