698 research outputs found
Fate of topological states in incommensurate generalized Aubry-Andr\'e models
We study one-dimensional optical lattices described by generalized
Aubry-Andr\'e models that include both commensurate and incommensurate
modulations of the hopping amplitude. This brings together two interesting
features of this class of systems: Anderson localization and the existence of
topological edge states. We follow changes of the single-particle energy
spectrum induced by variations of the system parameters, with focus on the
survival of topological states in the localized regime.Comment: 5 pages, 5 figure
Finite-size effects in Anderson localization of one-dimensional Bose-Einstein condensates
We investigate the disorder-induced localization transition in Bose-Einstein
condensates for the Anderson and Aubry-Andre models in the non-interacting
limit using exact diagonalization. We show that, in addition to the standard
superfluid fraction, other tools such as the entanglement and fidelity can
provide clear signatures of the transition. Interestingly, the fidelity
exhibits good sensitivity even for small lattices. Effects of the system size
on these quantities are analyzed in detail, including the determination of a
finite-size-scaling law for the critical disorder strength in the case of the
Anderson model.Comment: 15 pages, 7 figure
Portuguese crypto-Jews: The genetic heritage of a complex history
The first documents mentioning Jewish people in Iberia are from the Visigothic period. It was also in this period that the first documented anti-Judaic persecution took place. Other episodes of persecution would happen again and again during the long troubled history of the Jewish people in Iberia and culminated with the Decrees of Expulsion and the establishment of the Inquisition: some Jews converted to Catholicism while others resisted and were forcedly baptized, becoming the first Iberian Crypto-Jews. In the 18th century the official discrimination and persecution carried out by the Inquisition ended and several Jewish communities emerged in Portugal. From a populational genetics point of view, the worldwide Diaspora of contemporary Jewish communities has been intensely studied. Nevertheless, very little information is available concerning Sephardic and Iberian Crypto-Jewish descendants. Data from the Iberian Peninsula, the original geographic source of Sephardic Jews, is limited to two populations in Portugal, Belmonte, and Bragança district, and the Chueta community from Mallorca. Belmonte was the first Jewish community studied for uniparental markers. The construction of a reference model for the history of the Portuguese Jewish communities, in which the genetic and classical historical data interplay dynamically, is still ongoing. Recently an enlarged sample covering a wide region in the Northeast Portugal was undertaken, allowing the genetic profiling of male and female lineages. A Jewish specific shared female lineage (HV0b) was detected between the community of Belmonte and Bragança. In contrast to what was previously described as a hallmark of the Portuguese Jews, an unexpectedly high polymorphism of lineages was found in Bragança, showing a surprising resistance to the erosion of genetic diversity typical of small-sized isolate populations, as well as signs of admixture with the Portuguese host population
Influence of the particle size and animal slurry type on the potential of nitrogen mineralization after soil incorporation
RAMIRAN International ConferenceAnimal manures are rich in organic matter and nutrients, namely nitrogen (N) and, consequently, widely applied to
soil as organic fertilizers. However, a large part of the nitrogen contained in animal manures is in the organic form
and so not directly available for plants. Indeed, organic N has to be mineralized prior to plant uptake (Rees and
Castle, 2002). Several manure characteristics as the C:N ratio (Chadwick et al., 2000), the lignin content
(Kristensen, 1996) and the NH4 +/organic N ratio (Beauchamp and Paul, 1989) have been suggested as indicators of
the plant-available N. More recently, Fangueiro et al. (2008) showed that the potential of N mineralization (PNM) of
cattle slurry is inversely correlated with slurry particle size: finest fractions are the particle-size fractions from which
N mineralization occurs in slurries whereas coarser fractions are associated with immobilization. Furthermore,
Moller et al. (2002) reported that animal diet and anaerobic decomposition during storage in slurry channels and
stores affect the slurry particle size distribution. Such information is of great interest since the finest slurry particle
size should infiltrate the soil more easily and quickly relative to the coarser slurry particle size that should remain
close to soil surface. Furthermore, mechanical slurry separation is now performed in many pig and dairy farms in
order to improve slurry management in terms of nutrients utilization and reducing costs related to slurry storage.
Slurry separation by screw press leads to a nutrient rich organic solid fraction (0.7– 3.2 mm particles) that may be
composted and a liquid fraction that can be used for fertigation.
In the present study, three types of slurry (pig, duck and cattle) were separated into 4 slurry particle size
fractions (>2000 um, 2000-500 um, 500-100 um, <100 um) in order to assess the influence of the type of slurry and
slurry particle size on the PNM after soil incorporation
Pattern of mtDNA Variation in Three Populations from São Tomé e PrÃncipe
We have analysed the matrilineal genetic composition of three self-reported ethnic groups from São Tomé e PrÃncipe (Gulf of Guinea), an African archipelago whose settlement begun in the late fifteenth century. Sequence data from the hypervariable segments I (HVS-I) and II (HVS-II) were obtained for 30 Angolares, 35 Forros and 38 Tongas. The repertory of mtDNA lineages in São Tomé e PrÃncipe denoted a fully African maternal pool, primarily arisen from a Central/Southwestern substratum. The absence of any lineages of putative European descent means that the European impact at the mitochondrial pool was virtually nil. Angolares showed a clear reduction of mtDNA diversity and a slight genetic differentiation relative to Tongas or Forros, whereas the latter two groups did not present any signs of genetic boundaries between each other. The data obtained here reinforce the depiction of genetic substructuring in São Tomé e PrÃncipe previously derived from Y-chromosome STRs. In addition, the crossing of mtDNA and Y-STR information led to the inference that the female mediated gene flow within the archipelago was less restricted than the male, a pattern that could be framed in the cultural traditions and socio-historical interactions among the groups
Descritores botânicos, agronômicos e fenológicos do arroz (Oryza sativa L.).
O presente trabalho teve por objetivo apresentar os descritores morfológicos, agronômicos e fenológicos, bem como suas escalas e critérios utilizados na descrição das linhagens e genótipos de arroz, na Embrapa Arroz e Feijão, e que além de necessários para registro e proteção, são importantes para produtores e técnicos que conduzem campos de produção de sementes e úteis aos analistas que realizam análises de pureza em laboratórios oficiais e particulares de sementes.bitstream/CNPAF-2009-09/28149/1/doc_226.pd
Primary Sjögren's syndrome in children: Is a family approach indicated?
[No abstract available
Atividades do banco ativo de germoplasma de feijoeiro comum (Phaseolus vulgaris L.) da Embrapa.
O Banco Ativo de Germoplasma de Feijão, em parceria com a Embrapa Recursos Genéticos e Biotecnologia, tem contribuÃdo com a comunidade cientÃfica através do enriquecimento da variabilidade genética, disponibilizando mais de 14.000 acessos, com mais de 29.000 amostras distribuÃdas entre a comunidade cientÃfica em geral, o que evidencia a preocupação com problemas como a fome e o desenvolvimento de uma agricultura sustentável
Proportion, composition and potencial N mineralisation of particle size fractions obtained by mechanical separation of animal slurry
Research PaperMechanical slurry separation is a useful technology for slurry management on farms. The
characteristics of the fractions obtained depend on the separation efficiency and on the
characteristics of the original slurry. In the present work, three types of slurry e pig, cow
and duck e were separated into 4 particle size fractions. The proportion, composition in
terms of carbon and nutrients as nitrogen (N) phosphorus (P) and potassium (K) was
evaluated. The potential of N mineralisation of whole slurries, and each fraction after soil
application, was assessed. Results of the study showed that the characteristics of the slurry
fractions obtained depend strongly on the slurry type considered, namely on its dry matter
(DM) content. A positive value of PNM was observed with the 3 slurry types and 4 fractions
considered, indicating that no N immobilisation occurred. Nevertheless, results showed
that the value of PNM vary significantly (P < 0.05) with slurry types and slurry particle size
fractions
CaracterÃsticas do germoplasma de feijão (Phaseolus vulgaris L.) coletado na região litorânea do Rio Grande do Sul.
O objetivo desse trabalho foi apresentar informações sobre cor, tamanho e brilho das sementes das variedades usadas pelos agricultores da região litorânea do Rio Grande do Sul
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