6,960 research outputs found
Ages of Elliptical Galaxies: Single versus Multi Population Interpretation
New calibrations of spectrophotometric indices of elliptical galaxies as
functions of spectrophotometric indices are presented, permitting estimates of
mean stellar population ages and metallicities. These calibrations are based on
evolutionary models including a two-phase interstellar medium, infall and a
galactic wind.Free parameters were fixed by requiring that models reproduce the
mean trend of data in the color-magnitude diagram as well as in the plane of
indices Hbeta-Mg2 and Mg2-. To improve the location of faint ellipticals(MB
> -20) in the Hbeta-Mg2 diagram, down-sizing was introduced. An application of
our calibrations to a sample of ellipticals and a comparison with results
derived from single stellar population models is given. Our models indicate
that mean population ages span an interval of 7-12 Gyr and are correlated with
metallicities, which range from approximately half up to three times solar.Comment: 10 pages and 6 figures. Accepted for publication in Monthly Notices
of the Royal Astronomical Society Main Journa
Inverse type II seesaw mechanism and its signature at the LHC and ILC
The advent of the LHC, and the proposal of building future colliders as the
ILC, both programmed to explore new physics at the TeV scale, justifies the
recent interest in studying all kind of seesaw mechanisms whose signature lies
on such energy scale. The natural candidate for this kind of seesaw mechanism
is the inverse one. The conventional inverse seesaw mechanism is implemented in
an arrangement involving six new heavy neutrinos in addition to the three
standard ones. In this paper we develop the inverse seesaw mechanism based on
Higgs triplet model and probe its signature at the LHC and ILC. We argue that
the conjoint analysis of the LHC together with the ILC may confirm the
mechanism and, perhaps, infer the hierarchy of the neutrino masses.Comment: 24 pages, 22 figure
Doramectin e levamizole no controle dos helmintos de bovinos no início da estação seca.
Sessenta bovinos da raça Canchim, com idade aproximada de 15 meses e mantidos em pastagem de Brachiaria decumbens Slapf, foram distribuídos aleatoriamente em três tratamentos (l) com 20 animais cada, para controle de nematódeos gastrintestinais (TI- controle; Tj; Dorameclin, ml(/50kg/peso vivo, correspondendo a 200,ug/kg; e TJ Levamizole e ml(/40kg/peso vivo, equivalente a 3, 75mg do princípio ativo por quilograma de peso) A aplicação foi feita via parenteral, Subcutânea, sendo as infecções verminóticas obtidas naturalmente a pasto, O experimento foi realizado na fazenda Canchim, base física do Centro de Pesquisa de Pecuária do Sudeste (CPPSE), em São Carlos, SP, de abril a ,junho de 1995. Foram avaliados o peso corporal (PC), número de ovos por grama de fezes (OPG) e volume corpuscular médio (VCM), por seis períodos (P): 0, 14, 28, 42, 56 e 70 dias pós-dosificação. O modelo de análise incluiu, além da média, os efeitos de T: de P e da interação T x P. A partir dos 14 dias de avaliação, 0 Doraqmectin foi o que apresentou o menor OPG (P0,05) entre esses dois grupos a partir dos 42 dias. Os animais tratados apresentaram ganho de peso semelhantes (P>0,05) até o 42. dia Quanto ao controle, observou-se redução no ganho de peso (P0,05) entre si em toda a fase experimental, observando-se no entanto, valores inferiores (P,0,05) desta variável a partir dos 28 dias no grupo controle
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
Prevention of advancing degradation and recovery of degraded lands.
This chapter presents an overview on the main technological contributions of Embrapa and partners to halt land degradation, accelerated erosive processes, desertification, sanding, salinization, and to restore degraded lands, as established in target 15.3 (United Nations, 2018): By 2030, combat desertification, restore degraded land and soil, including land affected by desertification, drought and floods, and strive to achieve a land degradation-neutral world.bitstream/item/204882/1/Prevention-of-advancing-degradation-and-recovery-of-degraded-lands-2019.pd
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
The Heavy Quark Form Factors at Two Loops
We compute the two-loop QCD corrections to the heavy quark form factors in
case of the vector, axial-vector, scalar and pseudo-scalar currents up to
second order in the dimensional parameter . These terms are
required in the renormalization of the higher order corrections to these form
factors.Comment: 131 pages, 3 figure
Heavy quark form factors at two loops in perturbative QCD
We present the results for heavy quark form factors at two-loop order in
perturbative QCD for different currents, namely vector, axial-vector, scalar
and pseudo-scalar currents, up to second order in the dimensional
regularization parameter. We outline the necessary computational details,
ultraviolet renormalization and corresponding universal infrared structure.Comment: 13 pages Latex, Proceedings of XLI International Conference of
Theoretical Physics "Matter to the Deepest", Podlesice, Poland, September
3-8, 2017 and RADCOR 2017, St.~Gilgen Austria, Sept 24-29, 201
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