Neutrino Spin Flavor Precession and Leptogenesis

We argue that \Delta L=2 neutrino spin flavor precession, induced by the primordial magnetic fields, could have a significant impact on the leptogenesis process that accounts for the baryon asymmetry of the universe. Although the extra galactic magnetic fields is extremely weak at present time (about 10^{-9} Gauss), the primordial magnetic filed at the electroweak scale could be quite strong (of order 10^{17} Gauss). Therefore, at this scale, the effects of the spin flavor precession are not negligible. We show that the lepton asymmetry may be reduced by 50% due to the spin flavor precession. In addition, the leptogenesis will have different feature from the standard scenario of leptogenesis, where the lepton asymmetry continues to oscillate even after the electroweak phase transition.Comment: 5 pages, one figure. References adde

The ENSO signature in sea-surface temperature in the Gulf of California

We analyzed 21 years of sea-surface temperature satellite images to explore the spatial signature of the El Niño-Southern Oscillation signal in the Gulf of California. We used empirical orthogonal function analysis to extract the principal mode of the nonseasonal sea-surface temperature variability and compared it to the spatial signature of the Southern Oscillation Index. The first mode accounted for 80% of nonseasonal variability and its amplitude time series was significantly correlated to the Southern Oscillation Index (r = −0.58,P \u3c 0.01). The amplitude of this mode and its statistical relation to the El Niño is stronger during winter, which suggests that forcing of sea-surface temperature variability occurs through the disruption of the wind-driven upwelling corridor along the eastern coast due to El Niño-related atmospheric teleconnections. We also examined weekly time series of coastal sea-surface temperature coastal anomalies along the coast of North America, including the interior of the Gulf of California, during the strong 1997–98 El Niño. We found a poleward propagating signal that reached the mouth of the Gulf of California at the end of spring and continued its poleward propagation along the west coast of the peninsula slightly delayed; it also resulted in warming inside the Gulf of California. This observation may provide an explanation for the variable extension of the El Niño signature along the Pacific coast of North America

Folding studies of immunoglobulin-like β-sandwich proteins suggest that they share a common folding pathway

AbstractBackground: Are folding pathways conserved in protein families? To test this explicitly and ask to what extent structure specifies folding pathways requires comparison of proteins with a common fold. Our strategy is to choose members of a highly diverse protein family with no conservation of function and little or no sequence identity, but with structures that are essentially the same. The immunoglobulin-like fold is one of the most common structural families, and is subdivided into superfamilies with no detectable evolutionary or functional relationship.Results: We compared the folding of a number of immunoglobulin-like proteins that have a common structural core and found a strong correlation between folding rate and stability. The results suggest that the folding pathways of these immunoglobulin-like proteins share common features.Conclusions: This study is the first to compare the folding of structurally related proteins that are members of different superfamilies. The most likely explanation for the results is that interactions that are important in defining the structure of immunoglobulin-like proteins are also used to guide folding

Frontiers in the expansion of bioproducts

[no abstract available

Uma análise de soft systems methodology e sua utilização para melhoria do processo de desenvolvimento de cultivares em uma instituição de pesquisa agropecuária.

O objetivo desse artigo é apresentar algumas contribuições para enriquecer a reflexão sobre a Soft Systems Methodology (SSM) e contribuir para a sua prática em situações diversas do mundo organizacional. A SSM é explorada em um caso prático de aplicação na Embrapa Milho e Sorgo, com o objetivo de propor melhorias para o Processo de Desenvolvimento de Cultivares da empresa. O foco é direcionado para as características metodológicas da intervenção, enfatizando a adaptação feita ao processo de aplicação da SSM para se ajustar às contingências da situação. Ao final, avalia-se que a utilização da metodologia na forma flexível apresentada pode contribuir para o alcance de bons resultados para a organização

The corticotrophin-releasing factor/urocortin system regulates white fat browning in mice through paracrine mechanisms

Objectives: The corticotrophin-releasing factor (CRF)/urocortin system is expressed in the adipose tissue of mammals, but its functional role in this tissue remains unknown. Methods: Pharmacological manipulation of the activity of CRF receptors, CRF1 and CRF2, was performed in 3T3L1 white pre-adipocytes and T37i brown pre-adipocytes during in vitro differentiation. The expression of genes of the CRF/urocortin system and of markers of white and brown adipocytes was evaluated along with mitochondrial biogenesis and cellular oxygen consumption. Metabolic evaluation of corticosterone-deficient or supplemented Crhr1-null (Crhr1−/−) mice and their wild-type controls was performed along with gene expression analysis carried out in white (WAT) and brown (BAT) adipose tissues. Results: Peptides of the CRF/urocortin system and their cognate receptors were expressed in both pre-adipocyte cell lines. In vitro pharmacological studies showed an inhibition of the expression of the CRF2 pathway by the constitutive activity of the CRF1 pathway. Pharmacological activation of CRF2 and, to a lesser extent, inhibition of CRF1 signaling induced molecular and functional changes indicating transdifferentiation of white pre-adipocytes and differentiation of brown pre-adipocytes. Crhr1−/− mice showed increased expression of CRF2 and its agonist Urocortin 2 in adipocytes that was associated to brown conversion of WAT and activation of BAT. Crhr1−/− mice were resistant to diet-induced obesity and glucose intolerance. Restoring physiological circulating corticosterone levels abrogated molecular changes in adipocytes and the favorable phenotype of Crhr1−/− mice. Conclusions: Our findings suggest the importance of the CRF2 pathway in the control of adipocyte plasticity. Increased CRF2 activity in adipocytes induces browning of WAT, differentiation of BAT and is associated with a favorable metabolic phenotype in mice lacking CRF1. Circulating corticosterone represses CRF2 activity in adipocytes and may thus regulate adipocyte physiology through the modulation of the local CRF/urocortin system. Targeting CRF receptor signaling specifically in the adipose tissue may represent a novel approach to tackle obesity

Implicit Beliefs About Change: A Theory-Grounded Measure Applied to Community Organizations Serving Children, Youth, and Families

The aim of this study was to design and evaluate a theory-grounded measure that taps staff beliefs about the possibility for change in an organization which serves children, youth and families at the community level. The rationale for measuring staff beliefs about change derived from a motivation theory that features two contrasting beliefs structures (entity vs. incremental), and the goals and behavioral dispositions associated with each (Dweck & Leggett, 1988). Twenty-nine individuals associated with the community-based organization completed the newly developed Implicit Beliefs About Change Scale (IBACS) and participatedi n a semi-structured interview. Quantitative analyses indicated that the IBACS has good internal consistency, and yields sufficient response variance. Content analysis of the semi-structured interviews, used to assess the scale\u27s construct validity, uncovered distinctive and theory-consistent behavioral dispositions among those staff members whose beliefs regarding change could be characterized as either incremental or entity in nature. Implications for staff development and future research are discussed

Empresas globales y terciarización de las actividades económicas de la zona metropolitana de Guadalajara

En el contexto de la globalización, adquieren mayor relevancia los servicios al productor, aunados a las respuestas que manifiestan las empresas ante el proceso de reestructuración productiva en el que se ven inmersas. La ciudad de Guadalajara no es la excepción y es por ello que dicho fenómeno se ve influenciado actualmente a nivel económico y espacial

Isotropization of Bianchi type models and a new FRW solution in Brans-Dicke theory

Using scaled variables we are able to integrate an equation valid for isotropic and anisotropic Bianchi type I, V, IX models in Brans-Dicke (BD) theory. We analyze known and new solutions for these models in relation with the possibility that anisotropic models asymptotically isotropize, and/or possess inflationary properties. In particular, a new solution of curve ($k\neq0$) Friedmann-Robertson-Walker (FRW) cosmologies in Brans-Dicke theory is analyzed.Comment: 15 pages, 4 postscript figures, to appear in Gen. Rel. Grav., special issue dedicated in honour of Prof. H. Dehne