Radio constraints on dark matter annihilation in the galactic halo and its substructures

Annihilation of Dark Matter usually produces together with gamma rays comparable amounts of electrons and positrons. The e+e- gyrating in the galactic magnetic field then produce secondary synchrotron radiation which thus provides an indirect mean to constrain the DM signal itself. To this purpose, we calculate the radio emission from the galactic halo as well as from its expected substructures and we then compare it with the measured diffuse radio background. We employ a multi-frequency approach using data in the relevant frequency range 100 MHz-100 GHz, as well as the WMAP Haze data at 23 GHz. The derived constraints are of the order =10^{-24} cm3 s^{-1} for a DM mass m_chi=100 GeV sensibly depending however on the astrophysical uncertainties, in particular on the assumption on the galactic magnetic field model. The signal from single bright clumps is instead largely attenuated by diffusion effects and offers only poor detection perspectives.Comment: 12 pages, 7 figures; v2: some references added, some discussions enlarged; matches journal versio

Custo de produção de leitões em diferentes sistemas de produção: um estudo de caso no Oeste catarinense.

Este texto é o relato do estudo de caso de um estabelecimento suinícola no município de Presidente Castello Branco na região Oeste Catarinense. O objetivo foi estimar o custo de produção de leitões no atual cenário, no qual 33% do consumo de milho são produzidos no estabelecimento e, também, em dois cenários alternativos, um com autossuficiência em milho e o outro especializado em suínos. O estudo de caso utiliza uma abordagem sistêmica do estabelecimento agropecuário. As fontes foram entrevistas, software de gestão e preços fornecidos por órgãos públicos. O custo de produção foi calculado com planilha eletrônica desenvolvida pela rede Interpig. Os três diferentes cenários determinaram diferentes preços do milho, principal componente no custo de suínos. No sistema atual o custo de produção foi de R$88,22 por leitão, enquanto que no sistema especializado foi R$94,97 por leitão e, por fim, R$77,90 por leitão no sistema autossuficiente em milho, que apresentou o menor custo. This text is the report of a case study of a swine farm in the municipality of Presidente Castello Branco in the Western region of Santa Catarina. The objective was to estimate the cost of production of piglets on the actual scenario, in which 33$88,22 per piglet, while on the specialized system it was R$94,97 per piglet and, finally, R$77,90 per piglet on the self-sufficient system, which presented the lowest cost

Dosage compensation in birds

AbstractThe Z and W sex chromosomes of birds have evolved independently from the mammalian X and Y chromosomes [1]. Unlike mammals, female birds are heterogametic (ZW), while males are homogametic (ZZ). Therefore male birds, like female mammals, carry a double dose of sex-linked genes relative to the other sex. Other animals with nonhomologous sex chromosomes possess “dosage compensation” systems to equalize the expression of sex-linked genes. Dosage compensation occurs in animals as diverse as mammals, insects, and nematodes, although the mechanisms involved differ profoundly [2]. In birds, however, it is widely accepted that dosage compensation does not occur [3–5], and the differential expression of Z-linked genes has been suggested to underlie the avian sex-determination mechanism [6]. Here we show equivalent expression of at least six of nine Z chromosome genes in male and female chick embryos by using real-time quantitative PCR [7]. Only the Z-linked ScII gene, whose ortholog in Caenorhabditis elegans plays a crucial role in dosage compensation [8], escapes compensation by this assay. Our results imply that the majority of Z-linked genes in the chicken are dosage compensated

Potencial produtivo do milho em resposta ao uso de dejetos suínos e adubação química.

Projeto/Plano de Ação: 05.12.50200-03

Levantamento sistemático da produção e abate de suínos: 2006 e 2007.

bitstream/item/58227/1/doc122.pd

Estrutura dos contratos de integração na suinocultura de Santa Catarina.

bitstream/CNPSA/15857/1/publicacao_o333i3k.pdfPublicado também no site Engormix, 21 fev. 2011

Decaying Leptophilic Dark Matter at IceCube

We present a novel interpretation of IceCube high energy neutrino events (with energy larger than 60 TeV) in terms of an extraterrestrial flux due to two different contributions: a flux originated by known astrophysical sources and dominating IceCube observations up to few hundreds TeV, and a new flux component where the most energetic neutrinos come from the leptophilic three-body decays of dark matter particles with a mass of few PeV. Differently from other approaches, we provide two examples of elementary particle models that do not require extremely tiny coupling constants. We find the compatibility of the theoretical predictions with the IceCube results when the astrophysical flux has a cutoff of the order of 100 TeV (broken power law). In this case the most energetic part of the spectrum (PeV neutrinos) is due to an extra component such as the decay of a very massive dark matter component. Due to the low statistics at our disposal we have considered for simplicity the equivalence between deposited and neutrino energy, however such approximation does not affect dramatically the qualitative results. Of course, a purely astrophysical origin of the neutrino flux (no cutoff in energy below the PeV scale - unbroken power law) is still allowed. If future data will confirm the presence of a sharp cutoff above few PeV this would be in favor of a dark matter interpretation.Comment: 19 pages, 3 figures. Version published in JCAP. The analysis was performed in terms of the number of neutrino events instead of the neutrino flux, using a multi-Poisson likelihood approac