465 research outputs found
Levantamento detalhado de solos de áreas de produção florestal no Município de Ponte Serrada, oeste catarinense.
Introdução; Material; Levantamento de solos; Metodologia de trabalho; Resultados do mapeamento de solos; Legenda do mapeamento de solos; Classes de solo (definidas conforme Embrapa, 2006); Latossolos Brunos (LB); Nitossolos Brunos (LB); Cambissolos Húmicos (CH); Neossolos Litólicos (RL), Neossolos Regolíticos (RR) e afloramentos de rocha (AR); Gleissolos Melânicos; Considerações finais; Referências; Anexo - mapa detalhado de solo da Fazenda Cristo Rei, Celulose Irani S.A.bitstream/item/121209/1/Doc.-249-Joao-Bosco-versao-final.pd
Geoestatística integrada com estatística multivariada e geoprocessamento na definição de unidades de manejo para o Pinus taeda.
The prophylactic role of intravenous and long-term oral acyclovir after allogeneic bone marrow transplantation.
Eighty-two patients were randomly allocated to receive intravenous acyclovir 5 mg kg-1 t.d.s. for 23 days followed by oral acyclovir 800 mg 6-hourly for 6 months or matching placebos after allogeneic bone marrow transplantation. Herpes simplex and varicella zoster virus infections were significantly reduced during the period of administration of acyclovir. No reduction in cytomegalovirus infection was demonstrated. The drug was not toxic
Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics
An n(++)-GaAs/p(++)-AlGaAs tunnel junction with a peak current density of 10 100Acm(-2) is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10 000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500Acm(-2) and a voltage drop at 10 000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations
Modern agglutinated foraminifera from the Hovgård ridge, fram strait, west of Spitsbergen: Evidence for a deep bottom current
Deep-water agglutinated foraminifera on the crest of the Hovgârd Ridge, west of Spitsbergen, consist mostly of large tubular astrorhizids. At a boxcore station collected from the crest of Hovgârd Ridge at a water depth of 1169 m, the sediment surface was covered with patches of large (1 mm diameter) tubular forms, belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubutar species consisted mainly of opportunistic forms, such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms point to the presence of deep currents at this locality that are strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation in relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge, indicative of winnowing in a south-easterly direction
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
How Friendship Network Characteristics Influence Subjective Well-Being
This article explores how friendship network characteristics influence subjective well-being (SWB). Using data from the 2003 General Social Survey of Canada, three components of the friendship network are differentiated: number of friends, frequency of contact, and heterogeneity of friends. We argue that these characteristics shape SWB through the benefits they bring. Benefits considered are more social trust, less stress, better health, and more social support. Results confirm that higher frequency of contacts and higher number of friends, as well as lower heterogeneity of the friendship network are related to more social trust, less stress, and a better health. Frequency of contact and number of friends, as well as more heterogeneity of the friendship network increase the chance of receiving help from friends. With the exception of receiving help from friends, these benefits are in turn related to higher levels of SWB. Only the frequency of meeting friends face-to-face has a remaining positive direct influence on SWB
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