Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is still falling as the ambient temperature is reduced to 20 K. Stability tests of the FEMs, including a measurement of the 1/f knee frequency, also meet mission requirements. The 30 and 44 GHz FEMs have met or bettered the mission requirements in all critical aspects. The most sensitive LNAs have reached new limits of noise temperature for HEMTs at their band centres. The FEMs have well-defined linear polarization characteristcs.Comment: 39 pages, 33 figures (33 EPS files), 12 tables. Planck LFI technical papers published by JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/1748-022

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging

We present a measurement of the top quark pair ($t\bar{t}$) production cross section ($\sigma_{t\bar{t}}$) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using 230 pb$^{-1}$ of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the $t\bar{t}$ purity of the selected sample. For a top quark mass of 175 GeV, we measure $\sigma_{t\bar{t}}=8.6^{+1.6}_{-1.5}(stat.+syst.)\pm 0.6(lumi.)$ pb, in agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let

Search for W' bosons decaying to an electron and a neutrino with the D0 detector

This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let

Influence of scrotal bipartition on spermatogenesis yield and sertoli cell efficiency in sheep

Abstract With the objective to assess the effect of scrotal bipartition on spermatogenesis in sheep, the testes were used from 12 crossbred rams of sheep farms in the municipality of Patos, Paraíba, Brazil, distributed into two groups: GI with six rams with scrotal bipartition, and GII with six rams without scrotal bipartition. The testicular biometry was measured and the testes were collected, fixed in Bouin and fragments were processed to obtain histological slides. The spermatogenesis yield and the Sertoli cell efficiency was estimated by counting the cells of the spermatogenetic line at stage one of the seminiferous epithelium cycle and the Sertoli cells. The results were submitted to analysis of variance with the ASSISTAT v.7.6 program and the mean values were compared by the Student-Newman-Keuls test (SNK) at 5% significance. The testicular biometric parameters did not show statistical difference (p>0.05) between the groups. The meiotic, spermatogenetic and Sertoli cell efficiency were higher in bipartitioned rams (p0.05) between GI and GII. The results indicated that there is superiority in the spermatogenetic parameters of bi-partitioned rams, suggesting that these sheep present, as reported in goats, indication of better reproductive indices

Enabling Real‐Time, Non‐Ionizing 3D Imaging of Implantable Magnetic Cements Using Magnetic Particle Imaging

Abstract Magnetic Particle Imaging (MPI) is a non‐ionizing tomographic technique capable of real‐time 3D imaging with unmatched temporal resolution, reaching up to 46 vol/s. These features make MPI a promising tool for the monitoring of implantable resin composites, particularly in scenarios requiring frequent safe, and dynamic assessment. However, integrating magnetic responsiveness into medical materials without compromising their structural and biological integrity remains a challenge. In this study, it is presented the first strategy to enable MPI signal generation in a commercial implantable cement by depositing a continuous iron thin film onto its surface. This structured magnetic layer introduces directional magnetic anisotropy, resulting in an angle‐dependent MPI signal. This directional dependence can be explored to noninvasively track for the position and orientation of the implant, potentially benefiting applications in confined anatomical regions. In vitro assays confirmed that the incorporation of the magnetic layer does not compromise cytocompatibility. Altogether, these findings demonstrate that magnetic thin films can serve as anisotropic contrast sources for MPI, expanding the range of new possibilities for imaging implantable materials with orientation‐sensitive contrast and without ionizing radiation.</jats:p

Educação física escolar: estado da arte e direções futuras

O objetivo deste artigo é caracterizar e problematizar a Educação Física Escolar como prática profissional e subárea de pesquisa no campo mais amplo da Educação Física e das investigações educacionais. Para tal, inicialmente delimita o que é pesquisa em Educação Física Escolar, distinguindo-a da pesquisa sobre Educação Física Escolar, e quais seriam os objetos e hipóteses de pesquisa significativos para esta subárea. A seguir, analisa 289 artigos caracterizados como pesquisa em Educação Física Escolar, publicados em 11 periódicos (revistas) brasileiras, classificando-os nas categorias "ciclo de escolarização", "prática corporal " e "tema" investigados. Os resultados indicam que predominam os estudos no ensino fundamental, nas práticas "jogo" e "esporte", e pesquisas de cunho descritivo-interpretativo das aulas de Educação Física em várias dimensões e interrelações. Em conclusão, aponta a necessidade de maior direcionamento para as pesquisas nos âmbitos da didática, da implementação dos programas (currículos) formulados no bojo das políticas públicas, e da formação de professores. Por fim, alerta para a necessidade dos programas de pós-graduação em Educação Física no Brasil investirem mais nas pesquisas em Educação Física Escolar.The aim of this paper is to characterize and discuss the School Physical Education as a profession and sub-area of research in the broader academic field of Physical Education and educational research. To do that, it initially defines the difference between research in School Physical Education from research about School Physical Education, and point out the themes and research hypotheses for this subarea. It also analyses 289 articles characterized as research in School Physical Education, published in 11 Brazilian periodicals, classifying them in the following categories: "level of schooling", "bodily practice" and "theme". The results indicate that the majority of studies are carried out in elementary school, in "games" and "sports", and in descriptive and interpretative research in School Physical Education practices in several dimensions and interrelations. In conclusion, it points to the need to a focus in the research in teaching, the implementation of public curricula, and teacher education. Finally, it alerts to the need for Brazilian postgraduate programs in the academic field of physical education to invest more in research in School Physical Education subarea

Influência da cobertura vegetal de inverno e da adubação orgânica e, ou, mineral sobre as propriedades físicas de uma Terra Roxa Estruturada

O presente trabalho objetivou avaliar a influência da cobertura vegetal de inverno, constituída de uma associação de aveia preta (Avena strigosa Schreb) com nabo forrageiro (Raphanus sativus L.), da adubação orgânica com esterco de aves, da adubação orgânica e mineral e da adubação mineral sobre propriedades físicas do solo, numa Terra Roxa Estruturada do estado de Santa Catarina. As análises foram realizadas em amostras de solo coletadas em agosto de 1994 e janeiro de 1995, nas profundidades de 0-10, 10-20 e 20-30 cm, em um experimento iniciado em 1990. Verificou-se uma redução na estabilidade de agregados maiores que 4,76 mm, quando se fez uso de adubação orgânica, bem como aumento na estabilidade de agregados das classes de diâmetro 4,76 a 2,00 e 2,00 a 1,00 mm. Na camada de solo de 0-10 cm, observou-se que o adubo orgânico aumentou a macroporosidade e diminuiu a densidade do solo, enquanto a adubação orgânica e mineral reduziu a macroporosidade e aumentou a microporosidade e a densidade do solo