6,759 research outputs found
Strong evidences for a nonextensive behavior of the rotation period in Open Clusters
Time-dependent nonextensivity in a stellar astrophysical scenario combines
nonextensive entropic indices derived from the modified Kawaler's
parametrization, and , obtained from rotational velocity distribution. These
's are related through a heuristic single relation given by , where is the cluster age. In a nonextensive
scenario, these indices are quantities that measure the degree of
nonextensivity present in the system. Recent studies reveal that the index
is correlated to the formation rate of high-energy tails present in the
distribution of rotation velocity. On the other hand, the index is
determined by the stellar rotation-age relationship. This depends on the
magnetic field configuration through the expression , where
and denote the saturation level of the star magnetic field and its
topology, respectively. In the present study, we show that the connection
is also consistent with 548 rotation period data for single
main-sequence stars in 11 Open Clusters aged less than 1 Gyr. The value of
2.5 from our unsaturated model shows that the mean magnetic field
topology of these stars is slightly more complex than a purely radial field.
Our results also suggest that stellar rotational braking behavior affects the
degree of anti-correlation between and cluster age . Finally, we suggest
that stellar magnetic braking can be scaled by the entropic index .Comment: 6 pages and 2 figures, accepted to EPL on October 17, 201
The parameter at three loops and elliptic integrals
We describe the analytic calculation of the master integrals required to
compute the two-mass three-loop corrections to the parameter. In
particular, we present the calculation of the master integrals for which the
corresponding differential equations do not factorize to first order. The
homogeneous solutions to these differential equations are obtained in terms of
hypergeometric functions at rational argument. These hypergeometric functions
can further be mapped to complete elliptic integrals, and the inhomogeneous
solutions are expressed in terms of a new class of integrals of combined
iterative non-iterative nature.Comment: 14 pages Latex, 7 figures, to appear in the Proceedings of "Loops and
Legs in Quantum Field Theory - LL 2018", 29 April - 4 May 2018, Po
A nonextensive insight to the stellar initial mass function
the present paper, we propose that the stellar initial mass distributions as
known as IMF are best fitted by -Weibulls that emerge within nonextensive
statistical mechanics. As a result, we show that the Salpeter's slope of
2.35 is replaced when a -Weibull distribution is used. Our results
point out that the nonextensive entropic index represents a new approach
for understanding the process of the star-forming and evolution of massive
stars.Comment: 5 pages, 2 figures, Accepted to EP
Does e-learning policy drive change in Higher Education?: A case study relating models of organisational change to e-learning implementation
Due to the heightened competition introduced by the potential global market and the need for structural changes within organisations delivering e-content, e-learning policy is beginning to take on a more significant role within the context of educational policy per se. For this reason, it is becoming increasingly important to establish what effect such policies have and how they are achieved. This paper addresses this question, illustrating five ways in which change is understood (Fordist, evolutionary, ecological, community of practice and discourse-oriented) and then using this range of perspectives to explore how e-learning policy drives change (both organisational and pedagogic) within a selected higher education institution. The implications of this case are then discussed, and both methodological and pragmatic conclusions are drawn, considering the relative insights offered by the models and ways in which change around e-learning might be supported or promoted
Statistical stability of equilibrium states for interval maps
We consider families of multimodal interval maps with polynomial growth of
the derivative along the critical orbits. For these maps Bruin and Todd have
shown the existence and uniqueness of equilibrium states for the potential
, for close to 1. We show that these
equilibrium states vary continuously in the weak topology within such
families. Moreover, in the case , when the equilibrium states are
absolutely continuous with respect to Lebesgue, we show that the densities vary
continuously within these families.Comment: More details given and the appendices now incorporated into the rest
of the pape
Resistência de bovinos ao carrapato Boophilus microplus. II. Infestação natural.
Avaliação da resistência de bovinos a ectoparasitos, particularmente ao carrapato do boi.Resumo
Measuring Anomalous Couplings in H->WW* Decays at the International Linear Collider
Measurement of the Higgs coupling to W-bosons is an important test of our
understanding of the electroweak symmetry breaking mechanism. We study the
sensitivity of the International Linear Collider (ILC) to the presence of
anomalous HW+W- couplings using ZH -> nu nu WW* -> nu nu 4j events. Using an
effective Lagrangian approach, we calculate the differential decay rates of the
Higgs boson including the effects of new dimension-5 operators. We present a
Monte Carlo simulation of events at the ILC, using a full detector simulation
based on geant4 and a real event reconstruction chain. Expected constraints on
the anomalous couplings are given.Comment: 18 pages, 7 figures, 1 tabl
Curva de crescimento em altura de fêmeas Nelore, Aberdeen Angus x Nelore, Canchim x Nelore e Simental x nelore nascidas em duas estações do ano.
O objetico neste trabalho foi estimar as curvas de crescimento em alturas de fêmeas Nelo (NEL), Aberdeen Angus x Nelore (AN), Canchim X Nelore (CN) e Simental x Nelore (SN), medidas na garupa dos oito aos 90 meses de idade, nascidas em duas estações do ano (primavera ou outono) e submetidas a dois níveis de suplementação alimentar. Os dados foram ajustados pela função de Brody e os efeitos de grupos genético (GG) e tratamento alimentar (TRAT) sobre a curva foram avaliados separadamente por época de nascimento comparando-se um modelo reduzido, que estimou apenas uma curva independente dos efeitos de GG e TRAT, com modelos mais completos que incluíram os efeitos de GG ou de TRAT. Os resultados obtidos reveleram não haver efeito de suplementação alimentar. Os grupos genéticos estudados aparesentaram curvas de crescimento em altura diferentes entre si também para cada época de nascimento
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