5,340 research outputs found

    Baseline LHC machine parameters and configuration of the 2015 proton run

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    This paper shows the baseline LHC machine parameters for the 2015 start-up. Many systems have been upgraded during LS1 and in 2015 the LHC will operate at a higher energy than before and with a tighter filling scheme. Therefore, the 2015 commissioning phase risks to be less smooth than in 2012. The proposed starting configuration puts the focus on feasibility rather than peak performance and includes margins for operational uncertainties. Instead, once beam experience and a better machine knowledge has been obtained, a push in β\beta^* and performance can be envisaged. In this paper, the focus is on collimation settings and reach in β\beta^*---other parameters are covered in greater depth by other papers in these proceedings.Comment: submitted for publication in a CERN yellow report (Proceedings of the LHC Performance Workshop - Chamonix 2014

    The chemical structure of the very young starless core L1521E

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    L1521E is a dense starless core in Taurus that was found to have relatively low molecular depletion by earlier studies, thus suggesting a recent formation. We aim to characterize the chemical structure of L1521E and compare it to the more evolved L1544 pre-stellar core. We have obtained \sim2.5×\times2.5 arcminute maps toward L1521E using the IRAM-30m telescope in transitions of various species. We derived abundances for the species and compared them to those obtained toward L1544. We estimated CO depletion factors. Similarly to L1544, cc-C3_3H2_2 and CH3_3OH peak at different positions. Most species peak toward the cc-C3_3H2_2 peak. The CO depletion factor derived toward the HerschelHerschel dust peak is 4.3±\pm1.6, which is about a factor of three lower than that toward L1544. The abundances of sulfur-bearing molecules are higher toward L1521E than toward L1544 by factors of \sim2-20. The abundance of methanol is similar toward the two cores. The higher abundances of sulfur-bearing species toward L1521E than toward L1544 suggest that significant sulfur depletion takes place during the dynamical evolution of dense cores, from the starless to pre-stellar stage. The CO depletion factor measured toward L1521E suggests that CO is more depleted than previously found. Similar CH3_3OH abundances between L1521E and L1544 hint that methanol is forming at specific physical conditions in Taurus, characterized by densities of a few ×\times104^4 cm3^{-3} and NN(H2_2)\gtrsim1022^{22} cm2^{-2}, when CO starts to catastrophically freeze-out, while water can still be significantly photodissociated, so that the surfaces of dust grains become rich in solid CO and CH3_3OH, as already found toward L1544. Methanol can thus provide selective crucial information about the transition region between dense cores and the surrounding parent cloud.Comment: Accepted for publication in A&A, abstract abridge

    Manejo de Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) na cultura do morangueiro no Rio Grande do Sul.

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    Esta Circular Técnica tem como objetivo descrever a biologia de F. occidentalis na cultura do morangueiro, caracterizar o tipo de injúria causada pelo inseto em flores e frutos e fornecer informações para o monitoramento e o controle da espécie na cultura no Estado do Rio Grande do Sul.bitstream/item/73816/1/cir090.pd

    Caracterização de danos causados por Anastrepha fraterculus (Wiedemann) (Diptera, Tephritidae) e desenvolvimento larval em frutos de duas cultivares de quivizeiro (Actinidia spp.)

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    Os danos causados por A. fraterculus em três estágios de maturação de frutos de quivizeiro foram avaliados em pomar comercial, e, em laboratório, o desenvolvimento larval da espécie foi estudado, nas cultivares MG06 e Bruno. Frutos das duas cultivares foram infestados com A. fraterculus, em pomar comercial localizado em Farroupilha-RS, no início (30% do tamanho final), metade (90% do tamanho final) e final (ponto de colheita) do ciclo de desenvolvimento, e, em laboratório, desde o início da frutificação até a colheita. Na cultivar MG06, três dias após a primeira infestação, observou-se a formação de exsudato cristalino nos locais de punctura que evolui, na colheita, para rachaduras, depressões e primórdios de galerias nos frutos. Na mesma cultivar, registrou-se fibrose nos frutos infestados no fim do ciclo (ponto de colheita). Apesar de terem sidos computados ovos nos frutos, a campo não houve desenvolvimento larval nessa cultivar. Na Bruno, não foram constatados danos e ovos, indicando a imunidade da cultivar. Não houve queda de frutos atribuída a A. fraterculus nas duas cultivares. Verificou-se o desenvolvimento larval, em laboratório, quando os frutos apresentavam, no mínimo, 6,4% e 7,0% de sólidos solúveis totais, respectivamente, para as cultivares MG06 e Bruno

    Design of polarization-insensitive superconducting single photon detectors with high-index dielectrics

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    In this paper, the design of superconducting-nanowire single-photon detectors which are insensitive to the polarization of the incident light is investigated. By using high-refractive-index dielectrics, the index mismatch between the nanowire and the surrounding media is reduced. This enhances the absorption of light with electric field vector perpendicular to the nanowire segments, which is generally hindered in this kind of detectors. Building on this principle and focusing on NbTiN nanowire devices, we present several easy-to-realize cavity architectures which allow high absorption efficiency (in excess of 90%) and polarization insensitivity simultaneously. Designs based on ultranarrow nanowires, for which the polarization sensitivity is much more marked, are also presented. Finally, we briefly discuss the specific advantages of this approach in the case of WSi or MoSi nanowires

    High-Throughput Microfluidic Platform for 3D Cultures of Mesenchymal Stem Cells, Towards Engineering Developmental Processes

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    The development of in vitro models to screen the effect of different concentrations, combinations and temporal sequences of morpho-regulatory factors on stem/progenitor cells is crucial to investigate and possibly recapitulate developmental processes with adult cells. Here, we designed and validated a microfluidic platform to (i) allow cellular condensation, (ii) culture 3D micromasses of human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) under continuous flow perfusion, and (ii) deliver defined concentrations of morphogens to specific culture units. Condensation of hBM-MSCs was obtained within 3 hours, generating micromasses in uniform sizes (56.2 ± 3.9 μm). As compared to traditional macromass pellet cultures, exposure to morphogens involved in the first phases of embryonic limb development (i.e. Wnt and FGF pathways) yielded more uniform cell response throughout the 3D structures of perfused micromasses (PMMs), and a 34-fold higher percentage of proliferating cells at day 7. The use of a logarithmic serial dilution generator allowed to identify an unexpected concentration of TGFβ3 (0.1 ng/ml) permissive to hBM-MSCs proliferation and inductive to chondrogenesis. This proof-of-principle study supports the described microfluidic system as a tool to investigate processes involved in mesenchymal progenitor cells differentiation, towards a ‘developmental engineering’ approach for skeletal tissue regeneration
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