The Au-Ag (Zn, Pb, Mo, Cu) Sulfuro Vein, La Paloma district, Deseado Massif, Argentina: Geochemical characterization and new insights into the 4D evolution of ore shoots

Unravelling the 3D architecture of ore shoots and its evolution through time, thereby moving towards a 4D understanding of mineralization processes, requires an interdisciplinary approach based on the capability of carrying out extensive trenching and drilling as well as effectively integrating structural and geochemical analyses. Such conditions are offered in La Paloma district of the Deseado Massif, Argentina. Here, eight epithermal Au-Ag veins are hosted in Middle Jurassic volcanic rocks (Bajo Pobre Formation). The Au-Ag (Zn, Pb, Mo and Cu) Sulfuro Vein, representing the main ore body in the district, is a 750 m long, N to NW striking structure extending 230 m at depth. The geometry and distribution of ore shoots within the Sulfuro Vein are controlled by: (i) lithological and structural features, (ii) metal concentration, (iii) temperature of the fluids at the time of ore deposition, and (iv) remobilization processes. The highest values of Au, Ag, Cu, Mo, Pb, Zn and Sb are concentrated at depths between 50 and 100 m.a.s.l., while high Mo values occur also at greater depths in the southern segment of the vein. Molybdenum distribution in shallower sectors of the vein is controlled by its remobilization by later infill stages. The Au, Ag and Cu ore shoots are widely distributed in the southern and central segments of the vein, as are the areas of greater vein thickness. These ore shoots exhibit a sub-horizontal geometry consistent with dominant extensional faulting during mineralization. In the northern segment of the vein, the Au, Ag and Cu ore shoots are discontinuous and small, and show gentle to moderate plunges probably associated with variable fault kinematics and depletion of the fluid in these metals. Ore-shoots of Mo, Pb and Zn display high values along the longitudinal section and sub-horizontal geometry in the central and northern sectors of the vein, with high-grade Mo ore shoots decreasing to the north. The fact that Pb and Zn high grades extend up to the tip of the northern vein segment suggests that these metals continued to precipitate at lower temperatures, favoured by the permeability of the volcaniclastic units. All of the ore shoots exhibit steeper plunges towards the southern termination of the vein. Here, upward fluid flow may have been enhanced by the dilation associated with oblique-slip along the N-S striking segment of the steeply dipping Sulfuro Vein. The geochemical distribution of metals shows a slight vertical zonation and a distinct lateral zonation, which suggest hydrothermal fluids flowed northward from deeper zones in the southern sector of the vein

Uso de antihelmínticos en grandes establecimientos de producción equina de la Argentina

En el contexto actual de la resistencia a los antihelmínticos, el conocimiento sobre las prácticas de control parasitario y el uso de las drogas por parte de los veterinarios en el campo, es indispensable para formular estrategias sustentables para el manejo y el control de los principales nematodes intestinales que afectan a los equinos. Con este objetivo se desarrolló una encuesta entrevistando personalmente o telefónicamente a 80 veterinarios especializados en medicina equina y que asesoran y son responsables de la sanidad general de 85 establecimientos equinos que producen caballos de silla en el área centro y norte de la Argentina. El control parasitario fue estudiado en 17.711 equinos (con 48 a 1860 animales por establecimiento). En más del 65% de los establecimientos fueron tratados con una frecuencia de entre 3 y 4 veces al año. La ivermectina fue el antihelmíntico más empleado (99% de los establecimientos), seguido por los benzimidazoles (44%), pirantel (13%) y combinaciones de moxidectina/ oxfendazole (6%). A pesar de la información documentada en el país indicando la resistencia de Parascaris spp a las lactonas macrocíclicas y de los pequeños estróngilos a los bencimidazoles, el uso de estas drogas para controlar estos parásitos continúa siendo una práctica en la región estudiada. Los veterinarios involucrados con la especie equina deberían monitorear y conocer la eficacia de los antihelmínticos en cada establecimiento antes de instaurar programas de control parasitario. Esta información es crítica ya que la resistencia antihelmíntica debería considerarse como probable en potrillos y, adultos y ninguno los dos grupos químicos más usados en el área central de la Argentina pueden ser considerados como antihelmínticos de amplio espectro sin evidencias previas de su eficacia

Parascaris spp en el centro de Argentina: perspectivas para su control

Parascaris spp es el parásito de mayor prevalencia e importancia en potrillos de todo el mundo. Puede causar síndromes de mala absorción y retardos en el crecimiento en animales severamente parasitados. Sin embargo, la manifestación clínica más importante es la impactación del intestino delgado que puede ocurrir en una pequeña proporción de potrillos infectados y es asociado a un pronóstico reservado de sobrevida. Los animales adultos presentan inmunidad sólida luego de los dos años de vida y puede ser hallado ocasionalmente en esta categoría siendo de baja importancia clínica salvo casos excepcionales. El control se basa en la administración de antihelmínticos, pero la resistencia a las lactonas macrocíclicas es actualmente común en todo el mundo. En nuestro país no existen estudios sobre la prevalencia de estos fenómenos y los casos documentados pertenecen a dos establecimientos puntuales de la provincia de Córdoba1,2. El objetivo de este informe es expandir y actualizar datos y evidencias sobre la ineficacia de las lactonas macrocíclicas para el control de Parascaris spp en el área central de Argentina e informar sobre alternativas terapéuticas y nuevas herramientas para complementar los análisis coproparasitológicos con el fin de mejorar la sensibilidad diagnóstica y el control de este parásito

Dust amorphization in protoplanetary disks

High-energy irradiation of the circumstellar material might impact the structure and the composition of a protoplanetary disk and hence the process of planet formation. In this paper, we present a study on the possible influence of the stellar irradiation, indicated by X-ray emission, on the crystalline structure of the circumstellar dust. The dust crystallinity is measured for 42 class II T Tauri stars in the Taurus star-forming region using a decomposition fit of the 10 micron silicate feature, measured with the Spitzer IRS instrument. Since the sample includes objects with disks of various evolutionary stages, we further confine the target selection, using the age of the objects as a selection parameter. We correlate the X-ray luminosity and the X-ray hardness of the central object with the crystalline mass fraction of the circumstellar dust and find a significant anti-correlation for 20 objects within an age range of approx. 1 to 4.5 Myr. We postulate that X-rays represent the stellar activity and consequently the energetic ions of the stellar winds which interact with the circumstellar disk. We show that the fluxes around 1 AU and ion energies of the present solar wind are sufficient to amorphize the upper layer of dust grains very efficiently, leading to an observable reduction of the crystalline mass fraction of the circumstellar, sub-micron sized dust. This effect could also erase other relations between crystallinity and disk/star parameters such as age or spectral type.Comment: accepted for publication by A&

Comparison of gene expression during in vivo and in vitro postnatal retina development

Retina explants are widely used as a model of neural development. To define the molecular basis of differences between the development of retina in vivo and in vitro during the early postnatal period, we carried out a series of microarray comparisons using mouse retinas. About 75% of 8,880 expressed genes from retina explants kept the same expression volume and pattern as the retina in vivo. Fewer than 6% of the total gene population was changed at two consecutive time points, and only about 1% genes showed more than a threefold change at any time point studied. Functional Gene Ontology (GO) mapping for both changed and unchanged genes showed similar distribution patterns, except that more genes were changed in the GO clusters of response to stimuli and carbohydrate metabolism. Three distinct expression patterns of genes preferentially expressed in rod photoreceptors were observed in the retina explants. Some genes showed a lag in increased expression, some showed no change, and some continued to have a reduced level of expression. An early downregulation of cyclin D1 in the explanted retina might explain the reduction in numbers of precursors in explanted retina and suggests that external factors are required for maintenance of cyclin D1. The global view of gene profiles presented in this study will help define the molecular changes in retina explants over time and will provide criteria to define future changes that improve this model system

Protection of Visual Functions by Human Neural Progenitors in a Rat Model of Retinal Disease

BACKGROUND: A promising clinical application for stem and progenitor cell transplantation is in rescue therapy for degenerative diseases. This strategy seeks to preserve rather than restore host tissue function by taking advantage of unique properties often displayed by these versatile cells. In studies using different neurodegenerative disease models, transplanted human neural progenitor cells (hNPC) protected dying host neurons within both the brain and spinal cord. Based on these reports, we explored the potential of hNPC transplantation to rescue visual function in an animal model of retinal degeneration, the Royal College of Surgeons rat. METHODOLOGY/PRINCIPAL FINDINGS: Animals received unilateral subretinal injections of hNPC or medium alone at an age preceding major photoreceptor loss. Principal outcomes were quantified using electroretinography, visual acuity measurements and luminance threshold recordings from the superior colliculus. At 90–100 days postnatal, a time point when untreated rats exhibit little or no retinal or visual function, hNPC-treated eyes retained substantial retinal electrical activity and visual field with near-normal visual acuity. Functional efficacy was further enhanced when hNPC were genetically engineered to secrete glial cell line-derived neurotrophic factor. Histological examination at 150 days postnatal showed hNPC had formed a nearly continuous pigmented layer between the neural retina and retinal pigment epithelium, as well as distributed within the inner retina. A concomitant preservation of host cone photoreceptors was also observed. CONCLUSIONS/SIGNIFICANCE: Wild type and genetically modified human neural progenitor cells survive for prolonged periods, migrate extensively, secrete growth factors and rescue visual functions following subretinal transplantation in the Royal College of Surgeons rat. These results underscore the potential therapeutic utility of hNPC in the treatment of retinal degenerative diseases and suggest potential mechanisms underlying their effect in vivo

Incidence of Penicillium verrucosum in Grain Samples from Oat Varieties Commonly Grown in South Dakota

Ochratoxin A (OTA) can cause toxicogenic effects in humans and animals when contaminated food products are consumed. Oat ( Avena sativa), like any other cereal grain, can be contaminated with OTA when storage conditions are favorable for fungal growth and toxin production. South Dakota is among the leading oat-producing states in the United States. It is therefore important to determine the frequency of occurrence of the primary OTA-producing fungal species on oat grains produced in the state. In this study, we evaluated oat grain samples from South Dakota for the incidence of Penicillium verrucosum, the major ochratoxigenic fungus in temperate regions. Kernels from 12 oat cultivars grown at multiple locations in South Dakota from 2014 to 2016 (15 location-year combinations) were plated on dichloran yeast extract sucrose glycerol agar medium. P. verrucosum was detected on 0.30, 0.19, and 0.05% of the kernels tested in 2014, 2015, and 2016, respectively. Overall, 22 of the 360 evaluated samples had kernels contaminated with P. verrucosum. The fungal incidence of the contaminated samples ranged from 1 to 16%, and the majority of those samples originated from one location. All samples from 2014 and 2015 ( n = 240), except two, had no detectable levels of OTA. The concentration of OTA was well under the maximum limit recommended by the European Union for the two samples with detectable levels of OTA

Bencimidazole resistance in equine cyathostomes of the central argentina

The aim of this study was to evaluate the current state of the efficacy of benzimidazoles for control of small strongyles that parasitize horses in the central area of Argentina. In this context, two experiences were conducted involving a total of 107 horses. The first of these experiences was developed in six farms with a history of use of benzimidazoles and the second in horses whose past history of anthelmintic treatment was unknown. In both experiences a test of fecal egg count reductions (FECR) was carried out after treatment with an oral formulation of mebendazole 14% and triclorfon 48% at the dose of 5gr /100 kg of weight. The FECR was performed by comparing the averages (first experience) or individual values (second experience) on the number of eggs before and after treatment. Resistance to febendazole was observed in all farms in the first experience and approximately 60% of the horses in the second experience. Larval cultures after treatment showed only ciathostome third stage larvae. The results of this study indicate that populations of small strongyles resistant to benzimidazoles are extremely common in the central area of Argentina.Fil: Cerutti, J. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Cátedra de Parasitología y Enfermedades Parasitarias. Córdoba, ArgentinaFil: Cooper, L. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Cátedra de Parasitología y Enfermedades Parasitarias. Córdoba, ArgentinaFil: Caffe, G. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Cátedra de Parasitología y Enfermedades Parasitarias. Córdoba, ArgentinaFil: Cervilla, N. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Cátedra de Parasitología y Enfermedades Parasitarias. Córdoba, ArgentinaFil: Muchiut S. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Cátedra de Parasitología. Santa Fe, ArgentinaFil: Anziani, O. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Cátedra de Parasitología y Enfermedades Parasitarias. Córdoba, ArgentinaFil: Anziani, O. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria (EEA) Rafaela. Santa Fe, ArgentinaEl objetivo del presente estudio fue evaluar el estado actual de la eficacia de bencimidazoles para el control de pequeños estrongílidos que parasitan a equinos en el área central de Argentina. Se desarrollaron dos experiencias con un total de 107 equinos. La primera, en seis establecimientos con antecedentes de uso de bencimidazoles y la segunda, en equinos cuya historia previa de tratamientos antihelmínticos era desconocida. En todos los animales se realizó un test de reducción en el conteo de huevos (TRCH) luego del tratamiento con una formulación oral de mebendazole al 14% y triclorfon al 48% a la dosis de 5 gr/100 kg de peso vivo. El TRCH se realizó comparando promedios (primer experiencia) o valores individuales (segunda experiencia) del número de huevos pre y post tratamiento. Se observó resistencia a esta droga en todos los establecimientos de la primera experienciay en aproximadamente el 60% de animales pertenecientes a la segunda. Los coprocultivos post tratamiento mostraron solo larvas de tercer estadio pertenecientes a pequeños estrongílidos. Los resultados de este estudio indican que las poblaciones de pequeños estrongílidos con resistencia a bencimidazoles son extremadamente comunes en el área central de Argentina