Energy Efficiency-Spectral Efficiency Trade-Off of Transmit Antenna Selection

We investigate the energy efficiency-spectral efficiency (EE-SE) trade-off of transmit antenna selection/maximum ratio combining (TAS) scheme. A realistic power consumption model (PCM) is considered, and it is shown that using TAS can provide significant energy savings when compared to multiple-input multiple-output (MIMO) in the low to medium SE region, regardless the number of antennas, as well as outperform transmit beamforming scheme (MRT) for the entire SE range. For a fixed number of receive antennas, our results also show that the EE gain of TAS over MIMO becomes even greater as the number of transmit antennas increases. The optimal value of SE that maximizes the EE is obtained analytically, and confirmed by numerical results. Moreover, the influence of receiver correlation is also evaluated and it is shown that considering a non-realistic PCM can lead to mistakes when comparing TAS and MIMO

Probing the stellar initial mass function with high-z supernovae

The first supernovae (SNe) will soon be visible at the edge of the observable universe, revealing the birthplaces of Population III stars. With upcoming near-infrared missions, a broad analysis of the detectability of high-z SNe is paramount. We combine cosmological and radiationtransport simulations, instrument specifications and survey strategies to create synthetic observations of primeval core-collapse (CC), Type IIn and pair-instability (PI) SNe with the James Webb Space Telescope (JWST). We show that a dedicated observational campaign with theJWST can detect up to ~15 PI explosions, ~300 CC SNe, but less than one Type IIn explosion per year, depending on the Population III star formation history. Our synthetic survey also shows that ≈1-2 × 102 SNe detections, depending on the accuracy of the classification, are sufficient to discriminate between a Salpeter and flat mass distribution for high-redshift stars with a confidence level greater than 99.5 per cent. We discuss how the purity of the sample affects our results and how supervised learning methods may help to discriminate between CC and PI SNe. © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society

Occurrence of deformed wing virus variants in the stingless Melipona subnitida and honey Apis mellifera bee populations in North Eastern Brazil

Deformed wing virus (DWV) is now a global insect pathogen. Brazilian stingless bees are a diverse group often managed in close proximity to honey bees. We investigated the prevalence and load of DWV in 33 stingless bees (Melipona subnitida) and 12 honey bees (Apis mellifera) colonies from NE Brazil. DWV was detected in all colonies with the A and C-variants dominating M. subnitida and A-variant in A. mellifera. Viral loads were 8.83E+07 and 7.19E+07 in M. subnitida and A. mellifera, respectively. On Fernando de Noronha island DWV is low (<1E+03) in honey bees, but we detected high loads (1.6E+08) in nine island M. subnitida colonies, indicating no viral spill-over of DWV has occurred during the past 34 years. Furthermore, the ubiquitous presence of the DWV-C variant in M. subnitida colonies, and rarity in A. mellifera, may suggest limited viral exchange between these two species

Balanço e análise da sustentabilidade energética na produção orgânica de hortaliças.

Os insumos e serviços utilizados na produção vegetal representam custo energético. Dependendo desses fatores e das produtividades obtidas, a conversão da produção em energia determinará a eficiência energética do sistema. A agricultura orgânica somente atingirá a missão de preservação ambiental se tiver comprovada sustentabilidade energética. Neste trabalho, objetivou-se caracterizar os balanços energéticos dos cultivos orgânicos e analisar sua sustentabilidade, em comparação aos sistemas convencionais. Monitoraram-se campos de produção de dez culturas, de 1991 a 2000 em Domingos Martins-ES. Os dados do sistema convencional foram obtidos pelas médias dos coeficientes técnicos da região. Quantificaram-se os coeficientes técnicos, convertendo suas grandezas físicas em equivalentes energéticos, expressos em kcal. O sistema orgânico gastou 4.571.159 kcal ha-1 e apresentou 12.696.712 kcal ha-1 de energia inserida na colheita, mostrando balanço médio de 2,78. Esse valor foi similar ao obtido no sistema convencional (1,93). As participações dos componentes nos gastos do sistema orgânico foram embalagem (35,8%), composto orgânico (17,2%), irrigação (12,6%), sementes/mudas (12,4%) e mão-de-obra (11,0%), serviços mecânicos (5,0%) e frete (4,5%). Se os custos com embalagens fossem eliminados, os gastos do sistema orgânico seriam reduzidos para 2.930.113 kcal ha-1, aumentando sua eficiência. A maioria dos cultivos orgânicos pode ser considerada sustentável em transformação de energia, com balanços superiores a 1,00 e produção média diária de 80.421 kcal ha-1 por dia, superior à necessidade mínima de 58.064 kcal ha-1

Coastal upwelling and downwelling forcing of circulation in a semi-enclosed bay: Ria de Vigo

Semi-enclosed bays in upwelling regions are exposed to forcing related to winds, currents and buoyancy over the shelf. The influence of this external forcing is moderated by factors such as connectivity to the open ocean, shelter by surrounding topography, dimensions of the bay, and freshwater outflows. Such bays, preferred locations for ports, mariculture, marine industry, recreational activities and coastal settlement, present a range of characteristics, understanding of which is necessary to their rational management. Observations in such a semi-enclosed bay, the Ria de Vigo in Spain, are used to characterize the influence of upwelling and downwelling pulses on its circulation. In this location, near the northern limit of the Iberian upwelling system, upwelling events dominate during a short summer season and downwelling events the rest of the year. The ria response to the external forcing is central to nutrient supply and resultant plankton productivity that supports its high level of cultured mussel production. Intensive field studies in September 2006 and June 2007 captured a downwelling event and an upwelling event, respectively. Data from eight current profiler moorings and boat-based MiniBat/ADCP surveys provided an unprecedented quasi-synoptic view of the distribution of water masses and circulation patterns in any ria. In the outer ria, circulation was dominated by the introduction of wind-driven alongshore flow from the external continental shelf through the ria entrances and its interaction with the topography. In the middle ria, circulation was primarily related to the upwelling/downwelling cycle, with a cool, salty and dense lower layer penetrating to the inner ria during upwelling over the shelf. A warmer, lower salinity and less dense surface layer of coastal waters flowed inward during downwelling. Without external forcing, the inner ria responded primarily to tides and buoyancy changes related to land runoff. Under both upwelling and downwelling conditions, the flushing of the ria involved shelf responses to wind pulses. Their persistence for a few days was sufficient to allow waters from the continental shelf to penetrate the innermost ria. Longer term observations supported by numerical modeling are required to confirm the generality of such flushing events in the ria and determine their typical frequency, while comparative studies should explore how these scenarios fit into the range of conditions experienced in other semi-enclosed bays

Contribution of microscopy for understanding the mechanism of action against trypanosomatids

Transmission electron microscopy (TEM) has proved to be a useful tool to study the ultrastructural alterations and the target organelles of new antitrypanosomatid drugs. Thus, it has been observed that sesquiterpene lactones induce diverse ultrastructural alterations in both T. cruzi and Leishmania spp., such as cytoplasmic vacuolization, appearance of multilamellar structures, condensation of nuclear DNA, and, in some cases, an important accumulation of lipid vacuoles. This accumulation could be related to apoptotic events. Some of the sesquiterpene lactones (e.g., psilostachyin) have also been demonstrated to cause an intense mitochondrial swelling accompanied by a visible kinetoplast deformation as well as the appearance of multivesicular bodies. This mitochondrial swelling could be related to the generation of oxidative stress and associated to alterations in the ergosterol metabolism. The appearance of multilamellar structures and multiple kinetoplasts and flagella induced by the sesquiterpene lactone psilostachyin C indicates that this compound would act at the parasite cell cycle level, in an intermediate stage between kinetoplast segregation and nuclear division. In turn, the diterpene lactone icetexane has proved to induce the external membrane budding on T. cruzi together with an apparent disorganization of the pericellar cytoskeleton. Thus, ultrastructural TEM studies allow elucidating the possible mechanisms and the subsequent identification of molecular targets for the action of natural compounds on trypanosomatids.Fil: Lozano, Esteban Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Spina Zapata, Renata María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Barrera, Patricia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Tonn, Carlos Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Sosa Escudero, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin

Produção orgânica de rabanete em plantio direto sobre cobertura morta e viva.

O objetivo deste trabalho foi avaliar o uso de plantas espontâneas e cobertura viva de amendoim forrageiro(Arachis pintoi), associado à aplicação de composto orgânico na produção orgânica do rabanete em plantio direto. O experimento foi instalado na Universidade Federal do Acre, em Rio Branco-AC, de 15/06 a 14/07/2007. O delineamento experimental utilizado foi em blocos casualizados com parcelas subdivididas 4x3, em quatro repetições. As parcelas corresponderam ao sistema de plantio direto com cobertura viva de amendoim forrageiro, cobertura viva de planta espontânea, cobertura morta de planta espontânea e sistema de plantio em canteiro com solo descoberto. As subparcelas foram compostas pelas doses de composto orgânico de 5, 10 e 15 t ha-1 (base seca). O plantio direto na palha de plantas espontâneas teve desempenho semelhante ao preparo convencional do solo, ambos superiores ao plantio sobre as coberturas vivas. A produtividade do rabanete cv. Cometo, não foi afetada pelas doses crescentes de composto orgânico, podendo aplicar-se apenas 5 t ha-1, enquanto em preparo convencional do solo, o aumento da produtividade ultrapassa o plantio direto na palha apenas na dose maior de composto (15 t ha-1)

Does training with amplitude modulated tones affect tone-vocoded speech perception?

Temporal-envelope cues are essential for successful speech perception. We asked here whether training on stimuli containing temporal-envelope cues without speech content can improve the perception of spectrally-degraded (vocoded) speech in which the temporal-envelope (but not the temporal fine structure) is mainly preserved. Two groups of listeners were trained on different amplitude-modulation (AM) based tasks, either AM detection or AM-rate discrimination (21 blocks of 60 trials during two days, 1260 trials; frequency range: 4Hz, 8Hz, and 16Hz), while an additional control group did not undertake any training. Consonant identification in vocoded vowel-consonant-vowel stimuli was tested before and after training on the AM tasks (or at an equivalent time interval for the control group). Following training, only the trained groups showed a significant improvement in the perception of vocoded speech, but the improvement did not significantly differ from that observed for controls. Thus, we do not find convincing evidence that this amount of training with temporal-envelope cues without speech content provide significant benefit for vocoded speech intelligibility. Alternative training regimens using vocoded speech along the linguistic hierarchy should be explored