Three Flavour Majorana Neutrinos with Magnetic Moments in a Supernova

The resonant transition effects MSW and NSFP for three flavour Majorana neutrinos in a supernova are considered, where the transition magnetic moments are likely to play a relevant role in neutrino physics. In this scenario, the deformed thermal neutrino distributions are obtained for different choices of the electron-tau mixing angle. Detailed predictions for the future large neutrino detectors are also given in terms of the ratio between the spectra of recoil electrons for deformed and undeformed spectra.Comment: 20 pages, LaTeX, 5 figures.p

Modified quasilinearization method for solving nonlinear equations

Modified quasilinearization algorithm for solving nonlinear equation

Semiclassical Gravitational Effects in de Sitter Space at Finite Temperature

In the framework of finite temperature conformal scalar field theory on de Sitter space-time the linearized Einstein equations for the renormalized stress tensor are exactly solved. In this theory quantum field fluctuations are concentrated near two spheres of the de Sitter radius, propagating as light wave fronts. Related cosmological aspects are shortly discussed. The analysis, performed for flat expanding universe, shows exponential damping of the back-reaction effects far from these spherical objects. The obtained solutions for the semiclassical Einstein equations in de Sitter background can be straightforwardly extended also to the anti-de Sitter geometry.Comment: pag.14, 1 figure in poscript file available under request, Preprint DSF-8/9

Chronic traumatic encephalopathy in contact sports: A systematic review of all reported pathological cases

© 2015 Maroon et al. Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with head trauma. Although initially believed to affect only boxers, the at-risk population has expanded to encompass a much wider demographic, including American football players, hockey players, wrestlers, and military veterans. This expansion has garnered considerable media attention and public concern for the potential neurodegenerative effects of head trauma. The main aim of this systematic review is to give a complete overview of the common findings and risk factors for CTE as well as the status quo regarding the incidence and prevalence of CTE. This systematic review was performed using PubMed and MEDLINE and includes all neuropathologically confirmed cases of CTE in the medical literature to date, from the first published case in 1954 to August 1, 2013 (n = 153). The demographics, including the primary source of mTBI (mild Traumatic Brain Injury), age and cause of death, ApoE genotype, and history of substance abuse, when listed, were obtained from each case report. The demographics of American football players found to have CTE are also presented separately in order to highlight the most prevalent group of CTE cases reported in recent years. These 153 case reports of CTE represent the largest collection to date. We found that a history of mTBI was the only risk factor consistently associated with CTE. In addition, we found no relationships between CTE and age of death or abnormal ApoE allele. Suicide and the presence of premorbid dementia was not strongly associated with CTE. We conclude that the incidence of CTE remains unknown due to the lack of large, longitudinal studies. Furthermore, the neuropathological and clinical findings related to CTE overlap with many common neurodegenerative diseases. Our review reveals significant limitations of the current CTE case reporting and questions the widespread existence of CTE in contact sports

Coupled quintessence and the coincidence problem

We consider a model of interacting cosmological constant/quintessence, where dark matter and dark energy behave as, respectively, two coexisting phases of a fluid, a thermally excited Bose component and a condensate, respectively. In a simple phenomenological model for the dark components interaction we find that their energy density evolution is strongly coupled during the universe evolution. This feature provides a possible way out for the coincidence problem affecting many quintessence models.Comment: 15 pages, 11 figure

Heat-kernel Coefficients and Spectra of the Vector Laplacians on Spherical Domains with Conical Singularities

The spherical domains $S^d_\beta$ with conical singularities are a convenient arena for studying the properties of tensor Laplacians on arbitrary manifolds with such a kind of singular points. In this paper the vector Laplacian on $S^d_\beta$ is considered and its spectrum is calculated exactly for any dimension $d$. This enables one to find the Schwinger-DeWitt coefficients of this operator by using the residues of the $\zeta$-function. In particular, the second coefficient, defining the conformal anomaly, is explicitly calculated on $S^d_\beta$ and its generalization to arbitrary manifolds is found. As an application of this result, the standard renormalization of the one-loop effective action of gauge fields is demonstrated to be sufficient to remove the ultraviolet divergences up to the first order in the conical deficit angle.Comment: plain LaTeX, 23 pp., revised version, a misprint in expressions (1.8) and (4.38) of the second heat coefficient for the vector Laplacian is corrected. No other change

Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis

The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N_eff. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. In the present analysis we determine the upper bounds that BBN places on N_eff from primordial neutrino--antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations. We consider quite a wide range for the total lepton number in the neutrino sector, eta_nu= eta_{nu_e}+eta_{nu_mu}+eta_{nu_tau} and the initial electron neutrino asymmetry eta_{nu_e}^in, solving the corresponding kinetic equations which rule the dynamics of neutrino (antineutrino) distributions in phase space due to collisions, pair processes and flavor oscillations. New bounds on both the total lepton number in the neutrino sector and the nu_e -bar{nu}_e asymmetry at the onset of BBN are obtained fully exploiting the time evolution of neutrino distributions, as well as the most recent determinations of primordial 2H/H density ratio and 4He mass fraction. Note that taking the baryon fraction as measured by WMAP, the 2H/H abundance plays a relevant role in constraining the allowed regions in the eta_nu -eta_{nu_e}^in plane. These bounds fix the maximum contribution of neutrinos with primordial asymmetries to N_eff as a function of the mixing parameter theta_13, and point out the upper bound N_eff < 3.4. Comparing these results with the forthcoming measurement of N_eff by the Planck satellite will likely provide insight on the nature of the radiation content of the universe.Comment: 17 pages, 9 figures, version to be published in JCA

Advances in propagation of grapevine in the world.

Grapevine production by classical grafting methods and in commercial scale emerged over 130 years. This system remained handmade until the mid-1950s, when emerged the first international certification programs aimed at obtaining mother lants with high viral sanity. The necessity to increase the scale of production on industrial model and plant material production based on minimum morphological standards appeared at the end of the 1960s. Along the 1970s, research unlocked knowledge on emi-automated grafting, process hygiene, use of plant growth regulators and understanding of physiological events of rootstock-scion compatibility, callus formation and rooting. So, until the mid-2000s, certification schemes and propagation processes advanced little in technical standard. However, grapevine growing areas were expanded and demands for plant material increased, and new diseases emerged from contaminated nurseries. These new diseases (new viral complexes, phytoplasmas, bacteria and grapevine trunk diseases) were discovered by high-sensitivity diagnostic methods. Today, there is a new discussion on the nursery segment worldwide. The propagation techniques have been reviewed from the perspective of reducing the incidence of new diseases and minimum physiological damage of nursery plants during the production stages. Therefore, technological innovations regarding equipment, practices and production inputs have been incorporated in new certification schemes. However, despite these dvantages, these schemes have become more complex and multidisciplinary than previous ones, bringing difficulties in adaptation of nurserymen. Index-terms: Vitis grafting, nursery, certification, grapevine cuttings. Propagação de videiras a partir dos métodos clássicos de enxertia e em escala comercial teve origem há mais de 130 anos. Este sistema permaneceu artesanal até meados da década de 1950, quando se iniciaram os primeiros programas internacionais de certificação com foco na obtenção de plantas básicas com elevada sanidade para vírus. No fim da década de 1960, surgiu a necessidade de aumentar a escala para produção em um modelo industrial em que a muda apresentasse um padrão morfológico mínimo. Ao longo da década de 1970, aprofundaram-se as pesquisas relacionadas à automatização da prática de enxertia, à higienização do processo, ao uso de reguladores de crescimento e ao entendimento dos eventos fisiológicos da compatibilidade entre enxerto e porta-enxerto, formação de calos e enraizamentos. Assim, até meados dos anos 2000, os esquemas de certificação e o processo de propagação pouco evoluíram em termos técnicos. Porém, a medida que a área vitícola foi expandindo e a demanda por mudas aumentando, verificou-se que novas doenças se alastravam em escala global a partir de viveiros contaminados. Estas novas doenças (complexos virais, fitoplasmas, bactérias e fungos causadores de podridões vasculares) foram sendo descobertas à medida que os métodos de diagnose avançaram em sensibilidade de detecção. Hoje, surge nova discussão no segmento viveirista mundial fundamentada no fato de que o processo de propagação está sendo revisto sob o foco da redução de incidência das novas pragas e mínimo dano à muda ao longo das etapas da produção. Surgem, assim, inovações tecnológicas, tanto em equipamentos quanto em práticas e insumos, sendo incorporadas aos novos modelos de certificação. Mas, se por um lado, estes esquemas tornam-se cada vez mais multidisciplinares, por outro, a complexidade gerada pode trazer dificuldades para a adesão pelos viveiristas. Termos para indexação: Vitis enxertia, viveiro, certificação, mudas de videira