Sao Paulo State University

About: Sao Paulo State University is a education organization based out in São Paulo, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 55715 authors who have published 100436 publications receiving 1375332 citations.

High Levels of Diversity Uncovered in a Widespread Nominal Taxon: Continental Phylogeography of the Neotropical Tree Frog Dendropsophus minutus

Abstract: Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI) and the 16S rhibosomal gene (16S) for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered.

Tectonic history and the biogeography of the freshwater fishes from the coastal drainages of eastern Brazil: an example of faunal evolution associated with a divergent continental margin

Abstract: The eastern Brazilian coastal drainages are of great biogeographical significance, because of their highly endemic fish faunas. Phylogenetic patterns suggest a close biotic relationship between the rivers that flow into the Atlantic and those on the adjacent upland crystalline shield. However, little has been said on the dynamics of the geological processes causally related to the cladogenetic events between these areas. Distributional and phylogenetic patterns suggest a close association with the geological history of the passive continental margin of South America, from the Cretaceous to the present day. In this area megadome uplifts, rifting, vertical movements between rifted blocks and the erosive retreat of the South American eastern continental margin are hypothesized as the main geological forces controlling the distribution of freshwater fishes. The tectonic activity associated with the break-up of Gondwana and separation of South America and Africa formed six megadomes that control most of the current courses of the main crystalline shield river basins. Except for basins located at the edges of such megadomes, these river systems developed long, circuitous routes over the ancient Brazilian crystalline shield before emptying into the recently opened Atlantic Ocean. Initial cladogenetic events between upland crystalline drainages and Atlantic tributaries were probably associated with vicariant processes, and some ancient basal sister-groups of widespread inclusive taxa are found in these coastal hydrographic systems. Later, generalized erosive denudation resulted in an isostatic adjustment of the eastern margin of the platform. These, along with reactivations of ancient rifts led to vertical movements between rifted blocks and gave rise, in southeastern Brazil, to taphrogenic (rift related) basins. These basins, such as the Taubate, Sao Paulo, Curitiba and Volta Redonda basins, among others, captured adjacent upland drainages and fauna. The fossil fishes from the Tremembe Formation (Eocene-Oligocene of Taubate Basin) exemplify this process. Other taphrogenic systems of Tertiary age were also identified in other segments of the Atlantic continental margin, such as in Borborema province, in NE Brazil, with marked influence over drainage patterns. At the same time, erosive retreat of the eastern margin of the platform successively captured upland rivers, which became Atlantic tributaries evolving associated to main rift systems. The continued nature of these processes explains the mixed phylogenetic and distributional patterns between Atlantic tributaries and the upland crystalline shield areas, especially in the southeastern continental margin, represented by successively, less inclusive sister-groups associated with cladogenetic events from the Late Cretaceous to the present.

X̄ charts with variable sample size

Abstract: The usual practice in using a control chart to monitor a process is to take samples of size n from the process every h hours. This article considers the properties of the X chart when the size of each sample depends on what is observed in the preceding ..

Prevalence of dementia in Latin America: a collaborative study of population-based cohorts.

Abstract: Background: Dementia is becoming a major public health problem in Latin America (LA), yet epidemiological information on dementia remains scarce in this region. This study analyzes data from epidemiological studies on the prevalence of dementia in LA and compares the prevalence of dementia and its causes across countries in LA and attempts to clarify differences from those of developed regions of the world. Methods: A database search for population studies on rates of dementia in LA was performed. Abstracts were also included in the search. Authors of the publications were invited to participate in this collaborative study by sharing missing or more recent data analysis with the group. Results: Eight studies from six countries were included. The global prevalence of dementia in the elderly (≥65 years) was 7.1% (95% CI: 6.8-7.4), mirroring the rates of developed countries. However, prevalence in relatively young subjects (65-69 years) was higher in LA studies The rate of illiteracy among the elderly was 9.3% and the prevalence of dementia in illiterates was two times higher than in literates. Alzheimer's disease was the most common cause of dementia. Conclusions: Compared with studies from developed countries, the global prevalence of dementia in LA proved similar, although a higher prevalence of dementia in relatively young subjects was evidenced, which may be related to the association between low educational level and lower cognitive reserve, causing earlier emergence of clinical signs of dementia in the LA elderly population.

Electron transport in dye-sensitized solar cells based on ZnO nanotubes: evidence for highly efficient charge collection and exceptionally rapid dynamics.

Abstract: Dye-sensitized solar cells based on ordered arrays of polycrystalline ZnO nanotubes, 64 μm in length, are shown to exhibit efficient electron collection over the entire photoanode array length. Electrochemical impedance spectroscopy, open-circuit photovoltage decay analysis, and incident-photon-to-current efficiency spectra are used to quantify charge transport and lifetimes. Despite the relatively thick photoanode, the charge extraction time is found to be faster than observed in traditional TiO2 nanoparticle photoanodes. If the extraction dynamics are interpreted as diffusive, effective electron diffusion coefficients of up to 0.4 cm2 s−1 are obtained, making these pseudo-1D photoanodes the fastest reported for an operating DSC to date. Rapid electron collection is of practical significance because it should enable alternative redox shuttles, which display relatively fast electron-interception dynamics, to be employed without significant loss of photocurrent.