Impaired Auditory Temporal Selectivity in the Inferior Colliculus of Aged Mongolian Gerbils

Aged humans show severe difficulties in temporal auditory processing tasks (e.g., speech recognition in noise, low-frequency sound localization, gap detection). A degradation of auditory function with age is also evident in experimental animals. To investigate age-related changes in temporal processing, we compared extracellular responses to temporally variable pulse trains and human speech in the inferior colliculus of young adult (3 month) and aged (3 years) Mongolian gerbils. We observed a significant decrease of selectivity to the pulse trains in neuronal responses from aged animals. This decrease in selectivity led, on the population level, to an increase in signal correlations and therefore a decrease in heterogeneity of temporal receptive fields and a decreased efficiency in encoding of speech signals. A decrease in selectivity to temporal modulations is consistent with a downregulation of the inhibitory transmitter system in aged animals. These alterations in temporal processing could underlie declines in the aging auditory system, which are unrelated to peripheral hearing loss. These declines cannot be compensated by traditional hearing aids (that rely on amplification of sound) but may rather require pharmacological treatment

Every Other, Every Time - Rat Imitative Pattern Learning

Keshen (2011) showed that rats better learned to find visually-distinctive food locations arranged in a circle after watching an expert demonstrator rat forage in the setting. Phillips (2013) failed to find a similar imitative effect when 6 of 12 visually-identical food towers, also arranged in a circle, were consistently baited, but in a random pattern. The present experiment was designed to determine whether rats could display imitative learning using a more-regular pattern. Eight rats were assigned to be either demonstrators or observers. The experimental arena contained 12 identical food towers in a circular formation with every other tower baited. In Phase 1, the demonstrators were free to forage for 50 trials. In Phase 2, the observers were given the opportunity to forage for 20 trials, always after observing an expert demonstrator forage. During their 20 trials, the observers performed better than the demonstrators had during their first 20 trials

Methods of Treating Eye Conditions with Human Leukocyte Elastase (HLE) Inhibitory Agents

A method of reducing corneal scarring or fibroblast proliferation comprises applying to an area of a subject\u27s eye afflicted with the condition a corneal scar-fibroblast proliferation-reducing amount of a free or polymer-bound HLE inhibitory agent under conditions and for a period of time effective to attain the desired effect. A method of reducing neovascularization of corneal scar tissue comprises applying to an area of a subject\u27s eye afflicted with the condition a neovascularization-inhibitory amount of a free or polymer-bound HLE inhibitory agent under conditions and for a period of time effective to attain the desired effect

Efectos del fuego prescrito sobre matorral en las propiedades del suelo

The edaphic factors have been evaluated in a sloping segment of 2,68 ha of the «Tuña» woodland municipality of Tineo, affected for descending controlled burns of Erica and Ulex with a yield of 1,5 ha h-1. The soil alterations, immediately after the controlled burns and to the 7, 30 and 90 day, took place to 0-2, 2-5 and 5-10 cm of depth, showing the existence of a temporary increment of the soil fertility (increase of C, N, K, Ca, Mg and specially of available P). Immediately after the fire, clay fraction diminished and sand it increased and vice versa to the 7, 30 and 90 days of the controlled burns. The increase of soil fertility after the fire it could be taken advantage for the quick establishment of a vegetal cover due to the regrowth of the burned vegetation.Se evaluaron las propiedades edáficas en un segmento de pendiente de 2,68 ha del «monte Tuña», municipio de Tineo, afectado por quema controlada a hecho descendente de Erica y Ulex con un rendimiento de 1,5 ha h-1. Las alteraciones en el suelo, inmediatamente después de la quema y a los 7, 30 y 90 días, se produjeron a 0-2, 2-5 y 5-10 cm de profundidad, demostrando la existencia de un incremento temporal de la fertilidad de los suelos quemados (aumento de C, N, K, Ca, Mg y sobre todo de P asimilable). Justo después del fuego hubo una disminución de la fracción arcilla y un aumento de la fracción arena y viceversa a los 7, 30 y 90 días de la quema. El aumento de fertilidad tras la quema podría ser aprovechado para el rápido establecimiento de una cubierta vegetal debido a la brotación de la vegetación quemada

Niveles de monóxido de carbono en el aire urbano de San Miguel de Tucumán, Argentina

Carbon monoxide, a highly toxic gas, is one of the most common and widely distributed air pollutants; in San Miguel de Tucumán, Argentina, the main sources of emission are the vehicle engines and the fire produced by the burning of cane fields. The objective was to evaluate the local levels of carbon monoxide (CO) concentration in the urban air of San Miguel de Tucumán during a period of 13 years. Four monitoring stations with high population concentration were selected. Testo 625 measuring instruments with specific probe for CO were used. The measure-ments were made during the months of September, October and November during the period 2003-2015. The concentrations of CO were compared using Variance analysis of Kruskal & Wal-lis and Conover post-test at 5 % significance. Minimum, maximum and Percentiles values (P25, P50 and P75) were considered. Results: No significant differences were observed in annual CO concentrations (p = 0.7177), with min = 24ppm, P25 = 28 ppm, P50 =28.9 ppm, P75 = 32 ppm and maximum = 38 ppm. With significant differences in CO concentrations (p <0.001) according to month and sampling season, higher values were detected in the month of November in Station 4 with min=27.0ppm, P25=30.7 ppm, P50=31.0 ppm, P75=33.2 ppm and maximum=38.0 ppm. Conclusion: The City of San Miguel de Tucumán is located in a mountainous area with little air movement, which means it has a notable accumulation of atmospheric pollutants, with high concentrations of CO in the microcenter of this city.El monóxido de carbono (CO), gas altamente tóxico, es uno de los contaminantes atmosféricos más comunes y ampliamente distribuidos. En San Miguel de Tucumán, Argentina, las principa-les fuentes de emisión son los motores de vehículos y los incendios producidos por la quema de cañaverales. El objetivo de la presente investigación fue evaluar los niveles locales de concen-tración de CO en el aire urbano de San Miguel de Tucumán durante un período de trece años. Se seleccionaron cuatro estaciones de monitoreo con alta concentración poblacional. Se emplearon instrumentos de medición Testo 625, con sonda específica para CO. Las mediciones se realizaron en los meses de septiembre, octubre y noviembre durante el período 2003-2015. Las concen-traciones de CO se compararon empleando análisis de la varianza de Kruskal-Wallis y postest de Conover al 5 % de significación. Se consideraron valores mínimos, máximos y percentiles P25, P50 y P75. Resultados: No se observaron diferencias significativas en las concentraciones anuales de CO (p = 0,7177), con min = 24 ppm, P25 = 28 ppm, P50 = 28,9 ppm, P75 = 32 ppm y máximo = 38 ppm. Con diferencias significativas en las concentraciones de CO (p < 0,001), se-gún mes y estación de muestreo. Los mayores valores fueron detectados en el mes de noviembre en Estación 4, con min = 27,0 ppm, P25 = 30,7 ppm, P50 = 31,0 ppm, P75 = 33,2 ppm y máximo = 38,0 ppm. La ciudad de San Miguel de Tucumán se encuentra en zona montañosa, con escaso movimiento de aire, lo que determina una marcada acumulación de contaminantes atmosféricos, con concentraciones de CO elevadas en el microcentro de esta ciudad.Biotecnologí

Dusty wind of W Hya. Multi-wavelength modelling of the present-day and recent mass-loss

Low- and intermediate-mass stars go through a period of intense mass-loss at the end of their lives in a phase known as the asymptotic giant branch (AGB). During the AGB a significant fraction of their initial mass is expelled in a stellar wind. This process controls the final stages of their evolution and contributes to the chemical evolution of galaxies. However, the wind-driving mechanism of AGB stars is not yet well understood, especially so for oxygen-rich sources. Characterizing both the present-day mass-loss and wind structure and the evolution of the mass-loss rate of such stars is paramount to advancing our understanding of this processes. We modelled the dust envelope of W Hya using an advanced radiative transfer code. The dust model was analysed in the light of a previously calculated gas-phase wind model and compared to measurements available in the literature, such as infrared spectra, infrared images, and optical scattered light fractions. We find that the dust spectrum of W Hya can partly be explained by a gravitationally bound dust shell that probably is responsible for most of the amorphous Al$_2$O$_3$ emission. The composition of the large ($\sim$\,0.3\,$\mu$m) grains needed to explain the scattered light cannot be constrained, but probably is dominated by silicates. Silicate emission in the thermal infrared was found to originate from beyond 40 AU from the star and we find that they need to have substantial near-infrared opacities to be visible at such large distances. The increase in near-infrared opacity of the dust at these distances roughly coincides with a sudden increase in expansion velocity as deduced from the gas-phase CO lines. Finally, the recent mass loss of W Hya is confirmed to be highly variable and we identify a strong peak in the mass-loss rate that occurred about 3500 years ago and lasted for a few hundred years.Comment: 15 pages, 13 figure

Rotational inhomogeneities from pre-big bang?

The evolution of the rotational inhomogeneities is investigated in the specific framework of four-dimensional pre-big bang models. While minimal (dilaton-driven) scenarios do not lead to rotational fluctuations, in the case of non-minimal (string-driven) models, fluid sources are present in the pre-big bang phase. The rotational modes of the geometry, coupled to the divergenceless part of the velocity field, can then be amplified depending upon the value of the barotropic index of the perfect fluids. In the light of a possible production of rotational inhomogeneities, solutions describing the coupled evolution of the dilaton field and of the fluid sources are scrutinized in both the string and Einstein frames. In semi-realistic scenarios, where the curvature divergences are regularized by means of a non-local dilaton potential, the rotational inhomogeneities are amplified during the pre-big bang phase but they decay later on. Similar analyses can also be performed when a contraction occurs directly in the string frame metric.Comment: 21 pages, corrected typos, references added; to appear in Class. Quantum Gra

Anisotropic and strong negative magneto-resistance in the three-dimensional topological insulator Bi2Se3

We report on high-field angle-dependent magneto-transport measurements on epitaxial thin films of Bi2Se3, a three-dimensional topological insulator. At low temperature, we observe quantum oscillations that demonstrate the simultaneous presence of bulk and surface carriers. The magneto- resistance of Bi2Se3 is found to be highly anisotropic. In the presence of a parallel electric and magnetic field, we observe a strong negative longitudinal magneto-resistance that has been consid- ered as a smoking-gun for the presence of chiral fermions in a certain class of semi-metals due to the so-called axial anomaly. Its observation in a three-dimensional topological insulator implies that the axial anomaly may be in fact a far more generic phenomenon than originally thought.Comment: 6 pages, 4 figure