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31.
Singular spectrum analysis (SSA) is a technique that decomposes a time series into a set of components, such as, trend, harmonics, and residuals. Leaving out the residual components and adding up the others, the time series can be smoothed. This procedure has been used to model Brazilian electricity consumption and flow series. The PAR(p), periodic autoregressive models, has been broadly used in modelling energy series in Brazil. This paper presents an approach of this decomposition method, by fitting the PAR(p), considering its multivariate version known as multivariate SSA (MSSA). The method was applied to a vector of two wind speed series recorded at two locations in the Brazilian Northeast region. The obtained results, when compared to the univariate decomposition of each series, were far superior, showing that the spatial correlation between the two series were considered by MSSA decomposition stage.  相似文献   
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Chanda B  Asamoah OK  Blunck R  Roux B  Bezanilla F 《Nature》2005,436(7052):852-856
Voltage-gated ion channels are responsible for generating electrical impulses in nerves and other excitable cells. The fourth transmembrane helix (S4) in voltage-gated channels is the primary voltage-sensing unit that mediates the response to a changing membrane electric field. The molecular mechanism of voltage sensing, particularly with respect to the magnitude of the transmembrane movement of S4, remains controversial. To determine the extent of this transmembrane movement, we use fluorescent resonance energy transfer between the S4 domain and a reference point in the lipid bilayer. The lipophilic ion dipicrylamine distributes on either side of the lipid bilayer depending on the membrane potential, and is used here as a resonance-energy-transfer acceptor from donor molecules attached to several positions in the Shaker K+ channel. A voltage-driven transmembrane movement of the donor should produce a transient fluorescence change because the acceptor also translocates as a function of voltage. In Shaker K+ channels no such transient fluorescence is observed, indicating that the S4 segment does not translocate across the lipid bilayer. Based on these observations, we propose a molecular model of voltage gating that can account for the observed 13e gating charge with limited transmembrane S4 movement.  相似文献   
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TACI is mutant in common variable immunodeficiency and IgA deficiency   总被引:19,自引:0,他引:19  
The tumor necrosis factor receptor family member TACI (transmembrane activator and calcium-modulator and cyclophilin ligand interactor) mediates isotype switching in B cells. We found that 4 of 19 unrelated individuals with common variable immunodeficiency (CVID) and 1 of 16 individuals with IgA deficiency (IgAD) had a missense mutation in one allele of TNFRSF13B (encoding TACI). One of the four individuals with CVID had a single nucleotide insertion in the other TNFRSF13B allele. None of these mutations were present in 50 healthy subjects. TNFRSF13B mutations cosegregated with the phenotype of CVID or IgAD in family members of four index individuals that we studied. B cells from individuals with TACI mutations expressed TACI but did not produce IgG and IgA in response to the TACI ligand APRIL, probably reflecting impaired isotype switching. These results suggest that TACI mutations can result in CVID and IgAD.  相似文献   
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The Atlantic Forest is considered a hotspot biome, one of the most diverse in the world. Currently, due to deforestation, only 22% of the original cover remains, and only 7.5% well preserved. Despite the global importance of this biome, it still lacks basic studies, e.g. primary inventories. Cerambycidae is one of the most diverse groups of beetles, with high ecological and economic importance. The aim of this work was to survey the longhorn beetles (Cerambycidae) in three fragments (Pacangê, Vila 5 and Pancada Grande) of Atlantic Forest within Reserva Ecológica da Michelin (southern Bahia State, Brazil). A total of 166 individuals belonging to 53 species were recorded, 15 of them new geographical records for the state, and one for Brazil. The Shannon index (H) shows Pacangê (H = 2.665) as the most diverse fragment, followed by Pancada Grande (H = 2.658) and Vila 5 (H = 2.565). The most abundant species were Nyssodrysina lignaria (38 specimens collected), followed by Compsibidion vanum (31 specimens). One hundred and ten specimens were captured in Malaise traps, while in light traps only 56 specimens were caught; however, the richness and consequently the diversity in light traps was higher. This is one of the few studies carried out in Atlantic Forest surveying longhorn beetles, and provides primary data on these taxa, to help develop conservation policies for this threatened biome.  相似文献   
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ABSTRACT

Few studies have focused on the diverse fauna of southwestern Brazilian Amazonia. This region, spared from large-scale human occupation until the second half of the twentieth century, has been threatened by expanding agriculture, logging, and mining. Here, we describe a new nurse frog (Allobates, Aromobatidae) from the open highland habitats of Serra dos Pacaás Novos, one of the few large remnants of relatively intact native vegetation in the Brazilian state of Rondônia. The new species is diagnosed by its metallic orange dorsal colouration, weakly expanded discs on hands, and presence of two subarticular tubercles on Finger IV. A phylogenetic analysis based on DNA sequence data recovered the new species as more closely related to nurse frogs from the Madeira and Tapajós River basins; this pattern may reflect a history of dispersal uphill from a lowland ancestor. Our results also indicate that the generic assignment of Allobates alessandroi (Grant and Rodriguez, 2001), a high-elevation species from the Andes of Peru, needs to be reassessed; we discuss the phylogenetic affinities of this species based on morphological attributes.

http://www.zoobank.org/urn:lsid:zoobank.org:act:79131D82-B1B6-455D-AD9A-676D7E0783BC  相似文献   
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This paper deals with the function of farm land. The objective is to demonstrate that the socio-environmental function of land ownership has a different and broader role than mere administration. According to the current Brazilian Constitution, owning land gives a right to property that is bound by the social and environmental requirements prescribed by the law. Therefore, the nature of rights over land property has changed. The traditional capitalist ownership has been socialised, having as its organising and limiting principle the well-being of present and future generations. The new juridical structure is based on this foundation.  相似文献   
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