Aplicación de mezclas asfálticas tibias en la ciudad autónoma de Buenos Aires : Tramos experimentales

Las mezclas asfálticas tibias son elaboradas, colocadas y compactadas a temperaturas inferiores a las convencionales. La irrupción de las mismas en el escenario vial responde a una necesidad de dar respuesta a reclamos ambientales, y a la búsqueda de procesos de pavimentación eficientes desde todo punto de vista. En efecto, las mezclas tibias reducen considerablemente la emisión de CO2 en el proceso de producción con los beneficios que esta medida representa. Los principales avances, corresponden a experiencias llevadas a cabo en Europa y EEUU. En la Argentina y sobre la base de los trabajos que se han efectuado en el presente año, este tipo de mezcla seguramente empezará a utilizarse rápidamente en diferentes obras viales en el país. La importante disminución en las temperaturas de elaboración y colocación de estas mezclas, permite reducir los costos de energía y paralelamente las emisiones a la atmósfera. Asimismo existen otras interesantes ventajas, entre las que se destacan: la disminución del envejecimiento o rigidización prematura del asfalto por la planta asfáltica, la reducción del riesgo de segregación térmica, la disminución de las temporadas de veda en climas fríos, la mejora en los tiempos para la compactación del material, el mayor empleo de RAP en mezclas recicladas, la mejora de las condiciones de trabajo, etc. A través del Laboratorio de Pavimentos e Ingeniería Vial-LaPIV-, la Facultad de Ingeniería realizó un acuerdo de servicio técnico con la empresa YPF, siendo el objetivo del mismo: Diseñar un plan de trabajo para llevar adelante las etapas de desarrollo, ejecución (controles sobre los materiales y sobre las emisiones: CO, NOx, SO2, CO2) y el seguimiento de tramos experimentales de mezclas asfálticas de bajas emisiones. Identificar y definir la ejecución de tramos experimentales en lugares representativos del país. Seguimiento sistemático del comportamiento de los tramos. Elaboración de los reportes correspondientes y difusión de los mismos en foros técnicos de la especialidad. A la fecha se ha ejecutado el primer tramo de prueba con mezclas tibias en la Ciudad Autónoma de Buenos Aires, cuyas características y resultados alcanzados se describen el presente trabajo.Facultad de Ingenierí

Sensitivity to anti-Fas is independent of increased cathepsin D activity and adrenodoxin reductase expression occurring in NOS-3 overexpressing HepG2 cells

Stable overexpression of endothelial nitric oxide synthase (NOS-3) in HepG2 cells (4TO-NOS) leads to increased nitro-oxidative stress and upregulation of the cell death mediators p53 and Fas. Thus, NOS-3 overexpression has been suggested as a useful antiproliferative mechanism in hepatocarcinoma cells. We aimed to identify the underlying mechanism of cell death induced by NOS-3 overexpression at basal conditions and with anti-Fas treatment. The intracellular localization of NOS-3, the nitro-oxidative stress and the mitochondrial activity were analysed. In addition, the protein expression profile in 4TO-NOS was screened for differentially expressed proteins potentially involved in the induction of apoptosis. NOS-3 localization in the mitochondrial outer membrane was not associated with changes in the respiratory cellular capacity, but was related to the mitochondrial biogenesis increase and with a higher protein expression of mitochondrial complex IV. Nitro-oxidative stress and cell death in NOS-3 overexpressing cells occurred with the expression increase of pro-apoptotic genes and a higher expression/activity of the enzymes adrenodoxin reductase mitochondrial (AR) and cathepsin D (CatD). CatD overexpression in 4TO-NOS was related to the apoptosis induction independently of its catalytic activity. In addition, CatD activity inhibition by pepstatin A was not effective in blocking apoptosis induced by anti-Fas. In summary, NOS-3 overexpression resulted in an increased sensitivity to anti-Fas induced cell death, independently of AR expression and CatD activityThis study was supported by the Instituto de Salud Carlos III (FIS 09/00185). G. Ferrín was supported by the Networked Biomedical Research Center Hepatic and Digestive Diseases (CIBEREHD

The QUEST RR Lyrae Survey: Confirmation of the Clump at 50 kpc and Other Over-Densities in the Outer Halo

We have measured the periods and light curves of 148 RR Lyrae variables from V=13.5 to 19.7 from the first 100 sq. degrees of the QUEST RR Lyrae survey. Approximately 55% of these stars belong to the clump of stars detected earlier by the Sloan Digital Sky Survey. According to our measurements, this feature has ~10 times the background density of halo stars, spans at least 37.5 deg by 3.5 deg in right ascension and declination (>=30 by >=3 kpc), lies ~50 kpc from the Sun, and has a depth along the line of sight of ~5 kpc (1 sigma). These properties are consistent with the recent models that suggest it is a tidal stream from the Sgr dSph galaxy. The mean period of the type ab variables, 0.58 d, is also consistent. In addition, we have found two smaller over-densities in the halo, one of which may be related to the globular cluster Pal 5.Comment: 12 pages (including 4 figures). Accepted for publication in the ApJ Letter

Decay of similarity across tropical forest communities : integrating spatial distance with soil nutrients

Altres ajuts: Acord transformatiu CRUE-CSICUnderstanding the mechanisms that drive the change of biotic assemblages over space and time is the main quest of community ecology. Assessing the relative importance of dispersal and environmental species selection in a range of organismic sizes and motilities has been a fruitful strategy. A consensus for whether spatial and environmental distances operate similarly across spatial scales and taxa, however, has yet to emerge. We used censuses of four major groups of organisms (soil bacteria, fungi, ground insects, and trees) at two observation scales (1-m sampling point vs. 2,500-m plots) in a topographically standardized sampling design replicated in two tropical rainforests with contrasting relationships between spatial distance and nutrient availability. We modeled the decay of assemblage similarity for each taxon set and site to assess the relative contributions of spatial distance and nutrient availability distance. Then, we evaluated the potentially structuring effect of tree composition over all other taxa. The similarity of nutrient content in the litter and topsoil had a stronger and more consistent selective effect than did dispersal limitation, particularly for bacteria, fungi, and trees at the plot level. Ground insects, the only group assessed with the capacity of active dispersal, had the highest species turnover and the flattest nonsignificant distance−decay relationship, suggesting that neither dispersal limitation nor nutrient availability were fundamental drivers of their community assembly at this scale of analysis. Only the fungal communities at one of our study sites were clearly coordinated with tree composition. The spatial distance at the smallest scale was more important than nutrient selection for the bacteria, fungi, and insects. The lower initial similarity and the moderate variation in composition identified by these distance-decay models, however, suggested that the effects of stochastic sampling were important at this smaller spatial scale. Our results highlight the importance of nutrients as one of the main environmental drivers of rainforest communities irrespective of organismic or propagule size and how the overriding effect of the analytical scale influences the interpretation, leading to the perception of greater importance of dispersal limitation and ecological drift over selection associated with environmental niches at decreasing observation scales

The Main Belt Comets and ice in the Solar System

We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies

The quest RR lyrae survey. I. The first catalog

With the 1 m Schmidt telescope of the Llano del Hato Observatory and the QUEST CCD camera, 380 deg 2 of the sky have been surveyed for RR Lyrae variables in a band 2.°3 wide in declination (centered at δ = -1°) and covering right ascensions from 4. h1 to 6. h1 and from 8. h0 to 17. h0. The bright limit (due to CCD saturation) and the faint limit are V∼13.5 and ∼19.7, respectively, which correspond to ∼4 and ∼60 kpc from the Sun. We present a catalog of the positions, amplitudes, mean magnitudes, periods, and light curves of the 498 RR Lyrae variables that have been identified in this region of the sky. The majority of these stars (86%) are new discoveries. The completeness of the survey has been estimated from simulations that model the periods and light curves of real RR Lyrae variables and take into account the pattern of epochs of observation. While the completeness of the survey varies with apparent magnitude and with position, almost everywhere in the surveyed region it is quite high (\u3e80%) for the type ab RR Lyrae variables and between 30% and 90% for the low-amplitude type c variables

Panorama del consumo de las producciones vegetales intensivas de alimentos saludables, "Proalim Km 0", en tiempos de pandemia por Covid-19

El consumo de frutas y hortalizas (FyH) resulta imprescindible para una alimentación sana y equilibrada, y fortalecer el sistema inmunológico, frente al SARS-CoV-2. Con el objetivo de brindar un panorama sobre los cambios producidos en los hábitos de consumo de las producciones vegetales intensivas de alimentos saludables, en la población de la Provincia de Buenos Aires (PBA), ante el contexto de pandemia, se efectuaron dos encuestas, respecto de su producción, agroindustria, comercialización y consumo. Las mismas se realizaron en el marco del proyecto CIAC-940186 (INTA?AUDEAS?CONADEV) utilizando la plataforma Google-form (en el período 9-12/2020),(n:449), correspondiendo 91% a PBA, (área-CeRBAS: 80% y CRBAN: 11%). Los resultados indican predisposición a: la huerta familiar (80%), producción de frutales(64%); elaboración de conservas (70%) y preferencia por los productos de estación(93,5%). Al 93% le parece importante conocer el origen de los productos consumidos y72% compraría productos agroecológicos. El 47% cambió su percepción sobre la procedencia de FyH consumidas. Si bien compran en verdulerías, 1/3 destacó preferirlas de quintas locales. Respecto de nuevos canales, 7% compra mediante redes sociales y/o páginas web. En harinas de hortalizas (categoría que el 40%desconocía), se destacaron: garbanzo (49%), lenteja (28%) y arveja (20%). En porciones de FyHp/día: 10% consume cinco porciones/día, mientras 88,4% lo percibe como adecuado. Dicha disociación y el desconocimiento de recomendaciones oficiales detectado, en contraste con otros resultados de las encuestas, indican el enorme desafío de concientización, por parte de las instituciones, sobre cuál debe ser el consumo adecuado y sus múltiples beneficios.Fil: Bellaccomo, C.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Berriolo, M. J.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Caracotche, M. V.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Castagnino, Ana Maria. Crescaa, Facultad de Agronomía, Azul, Uncpba, Argentina; ArgentinaFil: Cendón, M. L.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Diaz, Karina Elizabeth. Crescaa, Facultad de Agronomía, Azul, Uncpba, Argentina; ArgentinaFil: Fasciglione. G.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: González Ferrín, M. S.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Mairosser, A.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Martinoia, G. I.. Crescaa, Facultad de Agronomía, Azul, Uncpba, Argentina; ArgentinaFil: Rogers, William John. Crescaa, Facultad de Agronomía, Azul, Uncpba, Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; ArgentinaFil: Rosini, M.B.. Crescaa, Facultad de Agronomía, Azul, Uncpba, Argentina; ArgentinaFil: Villagra C.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Yommi, A.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; ArgentinaFil: Zazzetta, M. L.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; Argentina41º Congreso Argentino de HorticulturaLa PLataArgentinaASAH