A radio continuum survey of the southern sky at 1420 MHz. Observations and data reduction

We describe the equipment, observational method and reduction procedure of an absolutely calibrated radio continuum survey of the South Celestial Hemisphere at a frequency of 1420 MHz. These observations cover the area 0h < R.A. < 24h for declinations less than -10 degree. The sensitivity is about 50 mK T_B (full beam brightness) and the angular resolution (HPBW) is 35.4', which matches the existing northern sky survey at the same frequency.Comment: 9 pages with 9 figures, A&A, in pres

Tecnologia social: uma estratégia para o desenvolvimento

Esta publicação apresenta reflexões de diversos representantes de instituições governamentais, do terceiro setor, da sociedade civil e de universidades sobre o tema da Tecnologia Social

Evolution favors protein mutational robustness in sufficiently large populations

BACKGROUND: An important question is whether evolution favors properties such as mutational robustness or evolvability that do not directly benefit any individual, but can influence the course of future evolution. Functionally similar proteins can differ substantially in their robustness to mutations and capacity to evolve new functions, but it has remained unclear whether any of these differences might be due to evolutionary selection for these properties. RESULTS: Here we use laboratory experiments to demonstrate that evolution favors protein mutational robustness if the evolving population is sufficiently large. We neutrally evolve cytochrome P450 proteins under identical selection pressures and mutation rates in populations of different sizes, and show that proteins from the larger and thus more polymorphic population tend towards higher mutational robustness. Proteins from the larger population also evolve greater stability, a biophysical property that is known to enhance both mutational robustness and evolvability. The excess mutational robustness and stability is well described by existing mathematical theories, and can be quantitatively related to the way that the proteins occupy their neutral network. CONCLUSIONS: Our work is the first experimental demonstration of the general tendency of evolution to favor mutational robustness and protein stability in highly polymorphic populations. We suggest that this phenomenon may contribute to the mutational robustness and evolvability of viruses and bacteria that exist in large populations

Inferring stabilizing mutations from protein phylogenies : application to influenza hemagglutinin

One selection pressure shaping sequence evolution is the requirement that a protein fold with sufficient stability to perform its biological functions. We present a conceptual framework that explains how this requirement causes the probability that a particular amino acid mutation is fixed during evolution to depend on its effect on protein stability. We mathematically formalize this framework to develop a Bayesian approach for inferring the stability effects of individual mutations from homologous protein sequences of known phylogeny. This approach is able to predict published experimentally measured mutational stability effects (ΔΔG values) with an accuracy that exceeds both a state-of-the-art physicochemical modeling program and the sequence-based consensus approach. As a further test, we use our phylogenetic inference approach to predict stabilizing mutations to influenza hemagglutinin. We introduce these mutations into a temperature-sensitive influenza virus with a defect in its hemagglutinin gene and experimentally demonstrate that some of the mutations allow the virus to grow at higher temperatures. Our work therefore describes a powerful new approach for predicting stabilizing mutations that can be successfully applied even to large, complex proteins such as hemagglutinin. This approach also makes a mathematical link between phylogenetics and experimentally measurable protein properties, potentially paving the way for more accurate analyses of molecular evolution

Crecimiento de renuevos y expansión de copas en claros del dosel de bosques de Nothofagus pumilio (lenga) en Chubut, Patagonia, Argentina

In the province of Chubut in Patagonia, Argentina, Nothofagus pumilio forests (locally known as lenga), are managed through selective cuts, which imply the opening of canopy gaps. This management scheme is carried out without taking into consideration the sapling requirements changes through neither a cutting cycle nor the precipitation gradient in which these forests thrive. To analyze these changes, we inferred the facilitation-competition balance between the canopy and regeneration studying the effects of precipitation levels, gap size and gap age on saplings growth in height on 45 canopy gaps artificially created between 1960 and 1993. Results shown that during the first 20 years since the gap opening, the regeneration growth is determined by light availability in mesic sites and by water availability in dry sites. However, the difference due to the precipitation levels gradually decreases over time. Moreover, in the period between 20 and 35 years after gap opening, in both mesic and xeric sites, light is the limiting factor to growth. This means that in xeric sites, saplings shift from a water-dependent to a light-dependent growth. The average closing rate of gaps due to lateral growth of trees bordering the gap is high enough so that within the proposed gap size range, the gap healing can occur before regeneration reaches the upper stratum. Consequently, in mesic sites the gap opening can be done by a single operation that generates gaps with diameters of approximately twice the average height of the canopy (D/H). While in xeric environments, lenga seedling establishment and initial growth require the cover of small gaps, but advanced regeneration requires bigger gaps to reach the canopy. For this reason, gaps should be opened in two stages: the first gaps should be opened with a D/H between 0.8 and 1, and after a cutting cycle of 35 years, these openings should be enlarged to a D/H between 1.5 and 2. The close relationship is maintained between the new cohort and the upper strata require special considerations regarding the evolution of the balance between positive and negative interactions during development. Our work highlights the need to adjust management practices to these spatial and temporal variations so as to achieve an optimal growth along the entire production cycle.En la provincia del Chubut, Patagonia Argentina, los bosques de Nothofagus pumilio (lenga) son manejados mediante cortas de selección, que implican la apertura de claros en el dosel. Este esquema de manejo es implementado sin tener en cuenta los requerimientos de los renuevos a lo largo de todo el ciclo de cortas ni el gradiente de precipitaciones presente en su distribución. Para analizar estos aspectos estimamos el balance facilitación-competencia entre el dosel y la regeneración, considerando los efectos de los niveles de precipitación, el tamaño de los claros y la antigüedad de los mismos, en 45 claros creados artificialmente entre los años 1960 y 1993. Los resultados muestran que durante los primeros 20 años desde la apertura del claro, el crecimiento de la regeneración está determinado por la disponibilidad de luz en los sitios mésicos y por la disponibilidad de agua en los sitios xéricos. Sin embargo, la diferencias entre los distintos niveles de precipitación decrece gradualmente a lo largo del tiempo y entre los 20 a 35 años luego de la apertura de los claros, tanto en los sitios mésicos como xéricos el factor limitante es la luz. Esto implica que en los sitios xéricos el crecimiento de los renuevos pasa de ser dependiente del agua a dependiente de la luz. Por otro lado, la tasa de cierre de los claros debida al crecimiento lateral de la copa de los árboles límite es lo suficientemente grande como para que pueda ocurrir el cierre antes de que los renuevos alcancen el estrato superior. Por lo tanto, en los sitios mésicos la apertura de los claros puede realizarse en una única operación que genere claros con un diámetro de aproximadamente el doble de la altura dominante del bosque (D/H ≈ 2). Por el contrario, en los sitios xéricos, el establecimiento y crecimiento inicial de los renuevos requiere la apertura de claros pequeños (D/H entre 0,8 y 1) que luego deberán ser ampliados para maximizar el crecimiento avanzado (D/H entre 1,5 y 2). La estrecha relación entre la regeneración y el dosel del bosque requiere la consideración de los posibles cambios en el balance entre los apsectos positivos y negativos de la misma a lo largo de todo su desarrollo. Nuestro trabajo resalta la necesidad de ajustar las prácticas de manejo a estas variaciones espaciales y temporales para alcanzar un desarrollo óptimo a lo largo del todo el ciclo productivo

Influence of feed delivery frequency on behavioural activity of dairy cows in freestall barns

Research on feeding management in more competitive free-stall settings indicates that frequency of delivery of fresh feed stimulates feed bunk attendance and can affect other aspects of cows’ time budgets apart from feeding such as time spent standing vs. lying down. The objective of this study was to examine how the frequency of feed delivery affects the behavior in two farms, one with a conventional and one with automatic milking system (AMS). The feeding frequency was varied from two to three times per day in the conventional dairy farm; one to two times per day in the AMS farm. The experiment was carried out in two different seasons. All behaviours of the cows were monitored in continuous by video recording. As expected, behavioral indices have been significantly affected by environmental conditions both in conventional farm and AMS farm. The variation in the frequency of feed delivery seems to affect the cow behavioural activity only in a limited way and modify only slightly the daily averages of the time spent in different activities mainly increasing the time cows spend standing (+4-5%)

Rituximab Unveils Hypogammaglobulinemia and Immunodeficiency in Children with Autoimmune Cytopenia

BACKGROUND: Rituximab (RTX; anti-CD20 mAb) is a treatment option in children with refractory immune thrombocytopenia, autoimmune hemolytic anemia (AHA), and Evans syndrome (ES). Prevalence and clinical course of RTX-induced hypogammaglobulinemia in these patients are poorly known. OBJECTIVE: To evaluate the prevalence and risk factors for persistent hypogammaglobulinemia (PH) after RTX use. METHODS: Clinical and immunologic data from children treated with RTX for immune thrombocytopenia, AHA, and ES were collected from 16 Italian centers and 1 UK center at pre-RTX time point (0), +6 months, and yearly, up to 4 years post-RTX. Patients with previously diagnosed malignancy or primary immune deficiency (PID) were excluded. RESULTS: We analyzed 53 children treated with RTX for immune thrombocytopenia (n = 36), AHA (n = 13), and ES (n = 4). Median follow-up was 30 months (range, 12-48). Thirty-two percent of patients (17 of 53) experienced PH, defined as IgG levels less than 2 SD for age at last follow-up (>12 months after RTX). Significantly delayed B-cell recovery was observed in children experiencing PH (hazard ratio, 0.55; P < .05), and 6 of 17 (35%) patients had unresolved B-cell lymphopenia at last follow-up. PH was associated with IgA and IgM deficiency, younger age at RTX use (51 vs 116 months; P < .01), a diagnosis of AHA/ES, and better response to RTX. Nine patients with PH (9 of 17 [53%]) were eventually diagnosed with a PID. CONCLUSIONS: Post-RTX PH is a frequent condition in children with autoimmune cytopenia; a sizable proportion of patients with post-RTX PH were eventually diagnosed with a PID. In-depth investigation for PID is therefore recommended in these patients

Distance to flood meadows as a predictor of use of Nothofagus pumilio forest by livestock and resulting impact, in Patagonia, Argentina

Seedling browsing by livestock has been indicated as major threat for forest sustainability use. Nothofagus pumilio forests are part of the livestock raising system in Patagonia, but because of the sparse understory cover, livestock graze mainly on flood meadows within the forest matrix. The complexity of the environment under study (forests and flood meadows) means that an adaptive predictor is needed to evaluate the intensity of resource use by livestock in order to assess its effect on the forest. Distance to flood meadows was evaluated as a predictor of the use intensity of the forest by livestock and its effect on the understory. The study was conducted at three sites in Chubut Province, Patagonia-Argentina. We established transects in the forest 320 m long, starting at the edge flood meadow-forest. In these transects, the livestock presence indicators (soil compaction, density of feces and trails) and composition of the understory were evaluated. Generalized Linear Model for repeated measures for longitudinal data were used. The indicators showed that distance is efficient for estimating forest use intensity by livestock. The understory varied with distance, the cover of exotic herbaceous was higher near the flood meadow. Far from the flood meadow, the cover was entirely composited of native species. The results support the use of distance to flood meadows as a tool for decision making in livestock and forest management in N. pumilio forests, and for further research on livestock effect on the forest.Fil: Quinteros, Claudia Pamela. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lopez Bernal, Pablo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; ArgentinaFil: Gobbi, Miriam E.. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bava, Jose Omar. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Centro de Investigación y Extensión Forestal Andino Patagónico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Relationships among lying and standing behaviour, body condition score and milk production in primiparous cows

The aim of this study was to examine the time budgets of 20 lactating primiparous Italian Holstein cows and to determine the relationships between lying and standing behaviour, milk production and Body Condition Score in the first stage of lactation. Parturition period ranged from 15 September to 31 March and in the first seven lactation days all cows were equipped with individual 3-axes acceleration and angular displacement loggers, throughout 150 days for lying and standing behaviour measuring. Body Condition Scores (BCS) were estimated weekly, while milk production (in both morning and evening milking) and humidity and temperature air data were collected daily. Average individual milk yield was 27.3 ± 6.24 kg/d and milking time was 4.95 ± 1.94 min. Individual BCS was on average 3.46 ± 0.30 and standing daily time was 13.5 ± 2.26 h/d. Primiparous cows with BCS at parturition &lt;3.25 quite regained BCS after 20 weeks of lactation, but produced on average 2.3 kg/d (p &lt;.001) less than the other cows. Primiparous cows with standing time &lt;14 h/d in the first 21 days of lactation showed higher BCS than the others cows (+0.11 on average, p &lt;.001), but did not produce more milk (+0.1 kg/d, p =.25) on average and showed smaller Linear Score (logarithm transformation of milk somatic cell count) than other cows. Primiparous cows with standing time &lt;14 h/d had higher number of lying bouts and less minutes between two lying bouts, probably due to a higher cow activity to feeding. Multiple regression on milk production showed a low effect of standing time, but primiparous cows lost 0.34 kg/d (p &lt;.05) for each standing hour.HIGHLIGHTS Primiparous cows with standing time &lt;14 h/d in the first 21 days of lactation showed higher BCS than the others cows Primiparous cows with standing time &lt;14 h/d showed smaller somatic cell count Primiparous cows lost 0.34 kg/d for each standing hour