Characterization of laser-produced fast electron source for integrated simulation of fast ignition

Relativistic electron currents (∼ 10 kA µm−2) are produced by focusing an intense laser beam (I ≥ 1019W cm−2) on a solid target. Based on this mechanism, an original inertial confinement fusion scheme has been proposed which consists in heating the compressed deuterium-tritium core with a laser-produced electron beam. Experimentally the fast electron source is not well characterized and simulations of both electron generation and transport remain a difficult task. Generally, transport codes are used with a simplified fast electron source as initial condition. The fast electron spectrum is assumed to be exponential with an adjustable temperature, and the divergence is characterized by a dispersion angle. To verify these assumptions, we have performed a characterization of the laser-driven fast electron source by means of PIC simulations [1] in the cases of a planar foil and a double cone

Generation of megatesla magnetic fields by intense-laser-driven microtube implosions

A microtube implosion driven by ultraintense laser pulses is used to produce ultrahigh magnetic fields. Due to the laser-produced hot electrons with energies of mega-electron volts, cold ions in the inner wall surface implode towards the central axis. By pre-seeding uniform magnetic fields on the kilotesla order, the Lorenz force induces the Larmor gyromotion of the imploding ions and electrons. Due to the resultant collective motion of relativistic charged particles around the central axis, strong spin current densities of ~ peta-ampere/cm2 are produced with a few tens of nm size, generating megatesla-order magnetic fields. The underlying physics and important scaling are revealed by particle simulations and a simple analytical model. The concept holds promise to open new frontiers in many branches of fundamental physics and applications in terms of ultrahigh magnetic fields.Comment: 22 pages, 7 figure

Relación entre la perimetría automatizada convencional y la topografía papilar realizada con el tomógrafo Heidelberg

espanolObjetivo: Determinar las correlaciones entre los parametros de la cabeza del nervio optico (CNO) obtenidos mediante el laser confocal de barrido (HRT), y los resultados de la perimetria automatizada convencional (PA) en sujetos normales, hipertensos oculares (HTO), sospechosos de glaucoma y glaucomatosos. Metodos: Cuatrocientos veintitres ojos fueron incluidos en el estudio y clasificados segun la presion intraocular basal, morfologia papilar y los resultados de la PA en 4 grupos: 87 normales, 192 hipertensos oculares, 70 sospechosos de glaucoma y 74 glaucomatosos. En los diferentes grupos diagnosticos, se calcularon los coeficientes de correlacion de Pearson entre los parametros de la CNO y la desviacion media (DM), la desviacion estandar de la media (DSM), el numero de puntos alterados en cada cuadrante del campo visual (superior-nasal, inferior-nasal, superior-temporal e inferior-temporal), el numero de puntos alterados segun los niveles de probabilidad y los valores umbral en cada punto de la PA. Resultados: En el grupo normal y de hipertensos oculares, se encontraron pocas correlaciones debiles entre los parametros del HRT y los resultados de la PA. La fuerza y el numero de correlaciones significativas aumentaron en el grupo de sospechosos de glaucoma. En el grupo de glaucomas, las correlaciones fueron mas fuertes, especialmente entre los cocientes excavacion/disco y anillo/disco con la DM (r=0,479) y entre el area de anillo con la DSM (r=0,444). Conclusiones: Se encontraron correlaciones debiles o moderadas entre algunos parametros de la CNO medidos con el HRT y los resultados de la PA, en el grupo de glaucomas. EnglishPurpose: To determine the correlations between optic nerve head (ONH) parameters measured with the Heidelberg Retina Tomograph (HRT), and the main outcomes of standard automated perimetry (SAP) in normal, ocular hypertensive, glaucoma suspects and glaucomatous subjects. Methods: Four hundred and twenty-three patients were enrolled in the study and classified into four groups depending on baseline intraocular pressure, optic nerve head morphology, and SAP results: 87 normal eyes, 192 ocular hypertensive eyes, 70 glaucoma suspects and 74 glaucomatous eyes. In the different diagnostic groups, Pearson's correlation coefficients were calculated between ONH parameters and mean deviation, pattern standard deviation (PSD), number of altered points in each quadrant of the visual field (superior-nasal, inferior-nasal, superior-temporal and inferior-temporal), number of points altered at different probability levels, and threshold values at each point of SAP. Results: In the normal and ocular hypertensive groups, only a few weak correlations were found between HRT and SAP parameters. The strength and number of significant correlations increased in the suspected glaucoma group. The glaucoma group had the strongest correlations, particularly between cup/disc ratio and rim/disc ratio with MD (r=0.479) and between rim area and PSD (r=0.444). Conclusions: Weak to moderate correlations were found between some ONH parameters obtained with the HRT and SAP results in the glaucoma grou

Aportación al conocimiento de los hongos del SE. de España VI: Esclerodermatales Licoperdales, Niludariales, Falales, Himenogasterales, Podaxales (Gasteromicetes,Basidiomicetes)

Resultados de las exploraciones micológicas realizadas entre 1977 y 1980 en 55 localidades de Murcia, Albacete, Almería, Alicante y Jaén, en lo referente a Gasteromicetes, con exclusión de Tulostomatales. 167 recolecciones corresponden a 28 especies, en general poco conocidas o nuevas para el SE de España. En conjunto pertenecen a: Scleroderma (3, con S. meridionale), Pisolithus (1), Astraeus (1), Sphaerobolus stellatus, Geastrum (6, con G. badium, G. minimum y G. pseudostriaturn), Langemannia (l), Lycoperdon (3, con L. lividuh y L. foetidum), Bovista (2, con, 3. aestivalis), Calvatia jl), Crucibulurn (l), Cyathus (2, con C. pygmaeus,conocido solamente del continente americano), Colus hirudinosus, Clathrus (1), Rhizopogon (2), Montagnea arenaria y Gyrophragmium dunalii.Résultats des explorations mycologiques menees entre 1977 et 1980 dans 55 localités des provinces de Murcia, Albacete, Almería, Alicante et Jaén, concernant les Gastéromycétes, Tulostomatales exclues. II s'agit en tout de 167 récoltes de 28 espéces, en general peu connues ou nouvelles pour le SE de l'Espagne. L'on peut souligner la présence de: Scleroderma meridionale, Sphaerobolus stellatus, Geastrum badium, G. minimum, G. pseudostriatum, Bovista aestivalis, Lycoperdon lividum, L. foetidum, Cyathus pygmaeus, Colus hirudinosus, Montagnea arenaria et Gyrophragmium dunalii

Gender Differences in Myogenic Regulation along the Vascular Tree of the Gerbil Cochlea

Regulation of cochlear blood flow is critical for hearing due to its exquisite sensitivity to ischemia and oxidative stress. Many forms of hearing loss such as sensorineural hearing loss and presbyacusis may involve or be aggravated by blood flow disorders. Animal experiments and clinical outcomes further suggest that there is a gender preference in hearing loss, with males being more susceptible. Autoregulation of cochlear blood flow has been demonstrated in some animal models in vivo, suggesting that similar to the brain, blood vessels supplying the cochlea have the ability to control flow within normal limits, despite variations in systemic blood pressure. Here, we investigated myogenic regulation in the cochlear blood supply of the Mongolian gerbil, a widely used animal model in hearing research. The cochlear blood supply originates at the basilar artery, followed by the anterior inferior cerebellar artery, and inside the inner ear, by the spiral modiolar artery and the radiating arterioles that supply the capillary beds of the spiral ligament and stria vascularis. Arteries from male and female gerbils were isolated and pressurized using a concentric pipette system. Diameter changes in response to increasing luminal pressures were recorded by laser scanning microscopy. Our results show that cochlear vessels from male and female gerbils exhibit myogenic regulation but with important differences. Whereas in male gerbils, both spiral modiolar arteries and radiating arterioles exhibited pressure-dependent tone, in females, only radiating arterioles had this property. Male spiral modiolar arteries responded more to L-NNA than female spiral modiolar arteries, suggesting that NO-dependent mechanisms play a bigger role in the myogenic regulation of male than female gerbil cochlear vessels

Multi-dimensionality and variability in folk classification of stingless bees (Apidae: Meliponini)

Background: Not long ago Eugene Hunn suggested using a combination of cognitive, linguistic, ecological and evolutionary theories in order to account for the dynamic character of ethnoecology in the study of folk classification systems. In this way he intended to question certain homogeneity in folk classifications models and deepen in the analysis and interpretation of variability in folk classifications. This paper studies how a rural culturally mixed population of the Atlantic Forest of Misiones (Argentina) classified honey-producing stingless bees according to the linguistic, cognitive and ecological dimensions of folk classification. We also analyze the socio-ecological meaning of binomialization in naming and the meaning of general local variability in the appointment of stingless bees. Methods: We used three different approaches: the classical approach developed by Brent Berlin which relies heavily on linguistic criteria, the approach developed by Eleonor Rosch which relies on psychological (cognitive) principles of categorization and finally we have captured the ecological dimension of folk classification in local narratives. For the second approximation, we developed ways of measuring the degree of prototypicality based on a total of 107 comparisons of the type "X is similar to Y" identified in personal narratives. Results: Various logical and grouping strategies coexist and were identified as: graded of lateral linkage, hierarchical and functional. Similarity judgments among folk taxa resulted in an implicit logic of classification graded according to taxa's prototypicality. While there is a high agreement on naming stingless bees with monomial names, a considerable number of underrepresented binomial names and lack of names were observed. Two possible explanations about reported local naming variability are presented. Conclusions: We support the multidimensionality of folk classification systems. This confirms the specificity of local classification systems but also reflects the use of grouping strategies and mechanisms commonly observed in other cultural groups, such as the use of similarity judgments between more or less prototypical organisms. Also we support the idea that alternative naming results from a process of fragmentation of knowledge or incomplete transmission of knowledge. These processes lean on the facts that culturally based knowledge, on the one hand, and biologic knowledge of nature on the other, can be acquired through different learning pathways.Fil: Zamudio, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); ArgentinaFil: Hilgert, Norma Ines. Consejo Nacional de Investigaciones Cientiâ­ficas y Tecnicas. Centro Cientifico Tecnologico Nordeste. Instituto de Biologia Subtropical. Instituto de Biologia Subtropical - Nodo Puerto Iguazu; Argentin