RNS derivation of N-point disk amplitudes from the revisited S-matrix approach

In the past year, in arXiv:1208.6066 we proposed a revisited S-matrix approach to efficiently find the bosonic terms of the open superstring low energy effective lagrangian (OSLEEL). This approach allows to compute the ${\alpha'}^N$ terms of the OSLEEL using open superstring $n$-point amplitudes in which $n$ is very much lower than $(N+2)$ (which is the order of the required amplitude to obtain those ${\alpha'}^N$ terms by means of the conventional S-matrix approach). In this work we use our revisited S-matrix approach to examine the structure of the scattering amplitudes, arriving at a closed form for them. This is a RNS derivation of the formula first found by Mafra, Schlotterer and Stieberger in arXiv:1106.2645, using the Pure Spinor formalism. We have succeeded doing this for the 5, 6 and 7-point amplitudes. In order to achieve these results we have done a careful analysis of the kinematical structure of the amplitudes, finding as a by-product a purely kinematical derivation of the BCJ relations (for N=4, 5, 6 and 7). Also, following the spirit of the revisited S-matrix approach, we have found the $\alpha'$ expansions for these amplitudes up to ${\alpha'}^6$ order in some cases, by only using the well known open superstring 4-point amplitude, cyclic symmetry and tree level unitarity: we have not needed to compute any numerical series or any integral involving polylogarithms, at any moment.Comment: 77 pages, 3 figure

Information theoretic interpretation of frequency domain connectivity measures

To provide adequate multivariate measures of information flow between neural structures, modified expressions of Partial Directed Coherence (PDC) and Directed Transfer Function (DTF), two popular multivariate connectivity measures employed in neuroscience, are introduced and their formal relationship to mutual information rates are proved.Comment: 17 pages, 1 figur

Low-Income Consumers in Brazil: Nuances of a Market That Can No Longer Be Ignored

The main goal of this paper is to better understand the low income Brazilian market, supported by two basic concepts: price unfairness and perceived product value. In order to meet the research objective a qualitative approach, based on two methodological procedures – observation and in-depth interviews –, was used. The findings indicate that small neighborhood retailers, despite lacking adequate physical infrastructure and management skills, play an important role in meeting the needs of low-income consumers. They offer convenience, personalized services, easy and uncomplicated credit (on an informal basis), and a product mix that matches the needs and desires of their customers. It was also found that although these small retailers charge higher prices than large supermarket chains, their customers still see value in their offerings and do not consider the prices asked to be unfair: they recognize that the benefits they receive outweigh the higher prices they pay. It was also found that low-income consumers relate with neighborhood retail stores in a basis that goes beyond the mere business, but in a cultural basis too. These small stores function not only as points of sale, but also as places where people can meet and discuss issues related to the local community. The principal contribution of this paper is in providing substantive information about the nuances of a market that has hitherto not been adequately explored but that holds a potential that can no longer be ignored. In Brazil, this market contains nearly 90 million consumers, eager to be included in the world of consumption. The findings presented by this study are of relevance not only to academic organisations and businesses, but also to social organizations and public policymakers responsible for improving the quality of life of the poor

Instituições de direito romano

Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à lei de Direitos Autorais, não disponibilizamos a obra na íntegra. 34(37) R748i STJ00078905 STJ00085599 4.ed

Assessment of a Socio-constructivist Model for Teacher Training

This article assesses a socio-constructivist model for training K-12 teachers in Brazil, in the use of Informatics in education. The method applied combines both face-to-face exchanges and a WEB-based distance approach made possible by Internet technology. The characteristics of such training and its main objectives are analyzed according to the collected data presented. A descriptive single case study research methodology is applied. The main conclusions reached by this researchbased on the use of a systemic frameworkare presented, mainly those addressing the importance of care and coherence for knowledge creation in a socio-constructivist training model developed with the help of the Internet. Comparisons between this model and the traditional one are also presented

Evaluation of exotic and adapted maize (Zea mays L.) germplasm crosses

An experiment was conducted to evaluate the effect of introgressing seven different exotic germplasms (Cateto, Caribbean Flint, Mexican Dent, Antigua, BS16, Suwan 1, and Tuxpeno) into two widely used Corn Belt germplasms (BS13(S)C4 and BS26). A 13 x 13 simple lattice design was used and the study was conducted at seven Iowa environments. The treatments included the adapted and exotic germplasm, the crosses and backcrosses between them, and check varieties. The crosses and backcrosses were made by using the parents in all possible combinations to obtain treatments with 100%, 75%, 50%, 25%, and 0% exotic germplasm;Treatments and treatment by environment interactions were observed to be highly significantly different (P ≤ 0.01) for grain yield, grain moisture, root and stalk lodging, and days-to-anthesis. Dropped ears and ear height were highly significant only for treatments. The results for grain yield (q/ha) suggest that the best percentage of exotic germplasm used was 50% (the F[subscript]1 hybrids of crosses between exotic by adapted germplasm). Exceptions were observed for Cateto, Caribbean Flint, and Tuxpeno crossed to BS26. Among the exotic germplasm used, Suwan 1 and Tuxpeno exhibited greater potential for continuing development. Both the Suwan 1 and Tuxpeno used in this study had only two years of selection for adaptation in the U.S. Corn Belt compared with the other exotic germplasms. Without considering the reciprocal crosses, the crosses Tuxpeno by BS13 (72.0 q/ha) and BS13 by Suwan 1 (69.1 q/ha) ranked fourth and fifth in the treatments per se, where the top ranked treatment was the cross of BSSS(R)C11 by BSCB1(R)C11, which yielded 79.4 q/ha. Higher values for midparent heterosis and coefficient of determination were also observed when either Tuxpeno or Suwan 1 were crossed with either BS13 or BS26. The higher values for midparent heterosis suggest that the allele frequencies were complementary in the F[subscript]1 hybrids in comparison with the parents. Overall, BS13(S)C4 combined better with the exotic germplasms than did BS26. With the results observed, the heterotic pattern Suwan 1 by Tuxpeno is suggested for exotic germplasm sources or Suwan 1 by BS26 and BS13 by Tuxpeno if exotic by adapted sources are used