Neutrino mixing in a left-right model

We study the mixing among different generations of massive neutrino fields in a $SU(2)_L \times SU(2)_R \times U(1)_Y$ gauge theory which includes Majorana and Dirac mass terms in the Yukawa sector. Parity can be spontaneously broken at a scale $v_R\simeq 10^3-10^4$ GeV. We discuss about possible candidates for the Yukawa coupling matrices and we found that the model can accommodate a consistent pattern for neutral fermion masses as well as neutrino oscillations. The left and right sectors can be connected by a new neutral current.Comment: 9 page

Approximate solutions for the single soliton in a Skyrmion-type model with a dilaton scalar field

We consider the analytical properties of the single-soliton solution in a Skyrmion-type Lagrangian that incorporates the scaling properties of quantum chromodynamics (QCD) through the coupling of the chiral field to a scalar field interpreted as a bound state of gluons. The model was proposed in previous works to describe the Goldstone pions in a dense medium, being also useful for studying the properties of nuclear matter and the in-medium properties of mesons and nucleons. Guided by an asymptotic analysis of the Euler-Lagrange equations, we propose approximate analytical representations for the single soliton solution in terms of rational approximants exponentially localized. Following the Pad\'e method, we construct a sequence of approximants from the exact power series solutions near the origin. We find that the convergence of the approximate representations to the numerical solutions is considerably improved by taking the expansion coefficients as free parameters and then minimizing the mass of the Skyrmion using our ans\"atze for the fields. We also perform an analysis of convergence by computation of physical quantities showing that the proposed analytical representations are very useful useful for phenomenological calculations.Comment: 13 pages, 3 eps figures, version to be published in Phys.Rev.

Valoração econômica da perda de solo na cultura de cana-de-açúcar colhida crua e queimada no município de Campos dos Goytacazes.

Este trabalho foi realizado no Município de Campos dos Goytacazes, RJ e teve como objetivo valorar economicamente as perdas de solo em relação aos nutrientes perdidos na cultura de cana-de-açúcar sob dois sistemas distintos de colheita, cana-de-açúcar crua e queimada em áreas de baixada e de tabuleiro. Utilizou-se a Universal Soil Loss Equation ? USLE e o método do custo de reposição de nutrientes, para realizar a estimação econômica das perdas de solo. Os resultados mostram que a taxa de perda de solo da cana-de-açúcar queimada foi quatro vezes maior quando comparada à taxa para cana-de-açúcar colhida crua para ambas as áreas estudadas. O custo de reposição dos nutrientes perdidos no cultivo da cana-de-açúcar sob sistema de colheita com queima prévia apresentou um valor de R$10,53 por hectare, já o custo para área com cana crua foi de R$ 2,61 por hectare em área de baixada e de R$43,59 por hectare para cana queimada e R$ 10,89 para cana crua em tabuleiro. Dessa forma, o sistema de manejo da colheita da cana crua contribui ambientalmente e economicamente para a preservação da fertilidade do solo

Reproductive management strategies to reduce postpartum anestrus in dual-purpose cattle

Objective: Share technical aspects and recommendations to improve the reproductive and productive efficiency of dual-purpose cattle. Design/methodology/approach: A review of scientific publications was carried out to show the importance of some factors that limit reproduction, as well as management strategies to increase the reproductive potential in dual-purpose cows. Results: Strategic supplementation and selection of females with greater weight gain at weaning and at one year of age reduces the age at puberty. The duration of postpartum anestrus is reduced by weaning calves at a few days or weeks of age, restricting suckling to short periods of the day, delaying suckling, and exposing cows to a bull a few days after postpartum. On average, the combined effect of delayed suckling and exposure of cows to a bull reduces postpartum anestrus to less than 50 d and the calving-conception interval to 84 days. Milk production and calf weight gain also are improved without affecting postpartum weight changes in cows. Study limitations/implications: Extensive management of dual-purpose cattle reduces the intensive use of some reproductive biotechnologies commonly applied in other animal production systems. Findings/conclusions: Improvement in the reproductive efficiency of dual-purpose cattle can be achieved by reducing the age at puberty and postpartum anestrus by using reproductive management strategies and minor modifications to common management practices.Objective: To share technical aspects and recommendations to improve the reproductive and productive efficiency of dual-purpose cattle. Design/Methodology/Approach: A review of scientific articles published in journals was carried out to show the importance of some factors that limit reproduction, as well as to identify management strategies to increase the reproductive potential in dual-purpose cows. Results: The duration of postpartum anestrus is reduced by weaning calves at a few days or weeks of age, restricting suckling to short periods of the day, delaying suckling, and exposing cows to a bull during postpartum. On average, the combined effect of delayed suckling and exposure of cows to a bull reduces postpartum anestrus to less than 50 d and the calving-conception interval to 84 days. Milk production and calf weight gain also are improved without affecting postpartum weight changes in cows. Study Limitations/Implications: Extensive management of dual-purpose cattle reduces the intensive use of some reproductive biotechnologies commonly applied in other animal production systems. Findings/Conclusions: Improvement in the reproductive efficiency of dual-purpose cattle can be achieved by reducing the postpartum anestrus by using reproductive management strategies and minor modifications to common management practices

Inserción laboral y empleabilidad de egresados universitarios de la Macro Región Centro del Perú

Objective. Was to determine the level of labor insertion of university graduates from the Macro Region of Central Peru. Method. The design was non-experimental; the research level was descriptive; The instrument used was the Labor Insertion questionnaire for university administration graduates, developed based on the perspective of Gómez-Cartolín (2015) which had 27 items, the dimensions were employability (with 15 items), and the employability dimension (12 items), the sample consisted of 315 university graduates from the Central Macro Region of Peru. Results. In the Junín region, 21.9% were men, and 22.5% were women; in Pasco 7.0% were men and 19.7% were women; In Huánuco 4.4% were men and 24.4% were women, making a total of 33.3% men and 66.7% women in the regions that make up the Central Macro Region of Peru. Conclusion. Labor insertion of the administration graduates of the Central Macro Region of Peru was medium, which indicates that they are working in activities related to their professional career, predominantly financial organizations.Objetivo. Determinar el nivel de inserción laboral de los egresados universitarios de la Macro Región del Centro del Perú. Métodos. La investigación fue de diseño no experimental y nivel descriptivo; el instrumento empleado fue el cuestionario de inserción laboral a egresados universitarios de Administración, desarrollado en base a la perspectiva de Gómez-Cartolín (2015) que constó de 27 ítems referidos a las dimensiones: empleabilidad (con 15 ítems) y ocupabilidad (12 ítems). La muestra estuvo conformada por 315 egresados universitarios de la Macro Región Centro del Perú. Resultados. En la región Junín, el 21,9 % eran varones, y el 22,5 % mujeres; en Pasco, el 7 % eran varones y el 19,7 % mujeres; en Huánuco 4,4 % eran varones y el 24,4 % mujeres; lo que hace un total de 33,3 % de varones y 66,7 % de mujeres en las regiones que conforman la Macro Región Centro del Perú. Conclusión. El nivel perceptual de inserción laboral de los egresados de Administración de la Macro Región Centro del Perú fue medio, lo cual indica que se encuentran laborando en actividades afines a su carrera profesional, predominando las organizaciones financieras

Agent based modelling helps in understanding the rules by which fibroblasts support keratinocyte colony formation

Background: Autologous keratincoytes are routinely expanded using irradiated mouse fibroblasts and bovine serum for clinical use. With growing concerns about the safety of these xenobiotic materials, it is desirable to culture keratinocytes in media without animal derived products. An improved understanding of epithelial/mesenchymal interactions could assist in this. Methodology/Principal Findings: A keratincyte/fibroblast o-culture model was developed by extending an agent-based keratinocyte colony formation model to include the response of keratinocytes to both fibroblasts and serum. The model was validated by comparison of the in virtuo and in vitro multicellular behaviour of keratinocytes and fibroblasts in single and co-culture in Greens medium. To test the robustness of the model, several properties of the fibroblasts were changed to investigate their influence on the multicellular morphogenesis of keratinocyes and fibroblasts. The model was then used to generate hypotheses to explore the interactions of both proliferative and growth arrested fibroblasts with keratinocytes. The key predictions arising from the model which were confirmed by in vitro experiments were that 1) the ratio of fibroblasts to keratinocytes would critically influence keratinocyte colony expansion, 2) this ratio needed to be optimum at the beginning of the co-culture, 3) proliferative fibroblasts would be more effective than irradiated cells in expanding keratinocytes and 4) in the presence of an adequate number of fibroblasts, keratinocyte expansion would be independent of serum. Conclusions: A closely associated computational and biological approach is a powerful tool for understanding complex biological systems such as the interactions between keratinocytes and fibroblasts. The key outcome of this study is the finding that the early addition of a critical ratio of proliferative fibroblasts can give rapid keratinocyte expansion without the use of irradiated mouse fibroblasts and bovine serum