3,423 research outputs found
Polarization-controlled single photons
Vacuum-stimulated Raman transitions are driven between two magnetic substates
of a rubidium-87 atom strongly coupled to an optical cavity. A magnetic field
lifts the degeneracy of these states, and the atom is alternately exposed to
laser pulses of two different frequencies. This produces a stream of single
photons with alternating circular polarization in a predetermined
spatio-temporal mode. MHz repetition rates are possible as no recycling of the
atom between photon generations is required. Photon indistinguishability is
tested by time-resolved two-photon interference.Comment: 4 pages, 3 figure
Helminth infections: enabling the World Health Organization road map
Helminthiases are considered among the most persistent public health problems. Control and/or elimination remains a global health challenge and the World Health Organization Road Map highlights critical gaps and actions required to reach the 2030 targets, among them the need for new and more effective treatment options. Stronger collaborations across different fields are required to reach these goals. The helminth elimination platform is one example of how knowledge of two different disease areas can be aligned to fuse expertise and break disease silos
Characterization of The Heat Transfer on Spray Quenching for Different Material Properties
A broad range of water spray applications as a means of two-phase cooling scheme has encouraged researches in the thermal management system to support safety and process efficiency in industries. In the application of above saturation temperature, the cooling process follows the boiling curve where the dissipated heat flux is figured out as a function of the wall temperature. Knowledge on constructing the boiling curve is an essential part in order to define the moving boundary, and boundary value problems occur in metal cooling process analysis involving heat transfer and phase change. The objective of the research was to characterize the boiling parameters on different materials in the regime of film boiling, transition boiling, and nucleate boiling as the basis for its boiling curve construction. To explain the influence of material properties, this work is featuring, firstly, the calculated vapor film thickness in film boiling regime by promoting self-developed analytical model of single droplet and, secondly, the calculated boiling width which indicates a strong combination of surface temperature and heat flux observed as the boiling phenomena. This is obtained by calculating the propagation of wetting front and 100 oC points. This experimental work employed a volumetric spray flux of 4.2, 10 and 13.7 kg/m2s to cool a hot metal samples of aluminum alloy AA6082 and nickel heated up to 560 °C. An infrared camera was used to record the temperature drop over time. Heat flux calculation follows the numerical procedure according to 1D energy balance model. Calculated vapor film thickness explains why the HTC tends to increase with the decrease of the surface temperature. Leidenfrost and Departure from Nucleate Boiling (DNB) temperatures are found to be inversely proportional to the heat penetration coefficient of the metal while maximum heat flux and boiling width increase with it
A Case of Dropped Head plus Syndrome
A patient developed neck extensor weakness along with symmetrical, mild proximal extremity weakness. Electrodiagnostic findings were minimal. Subsequently muscle biopsy was undertaken which showed myopathic changes as well as rimmed vacuoles. This case highlights the discussion of histopatholgical findings seen in neck extensor weakness when it occurs in isolation as well as when it is associated with weakness in other distribution
A nanoflare model for active region radiance: application of artificial neural networks
Context. Nanoflares are small impulsive bursts of energy that blend with and
possibly make up much of the solar background emission. Determining their
frequency and energy input is central to understanding the heating of the solar
corona. One method is to extrapolate the energy frequency distribution of
larger individually observed flares to lower energies. Only if the power law
exponent is greater than 2, is it considered possible that nanoflares
contribute significantly to the energy input.
Aims. Time sequences of ultraviolet line radiances observed in the corona of
an active region are modelled with the aim of determining the power law
exponent of the nanoflare energy distribution.
Methods. A simple nanoflare model based on three key parameters (the flare
rate, the flare duration time, and the power law exponent of the flare energy
frequency distribution) is used to simulate emission line radiances from the
ions Fe XIX, Ca XIII, and Si iii, observed by SUMER in the corona of an active
region as it rotates around the east limb of the Sun. Light curve pattern
recognition by an Artificial Neural Network (ANN) scheme is used to determine
the values.
Results. The power law exponents, alpha 2.8, 2.8, and 2.6 for Fe XIX, Ca
XIII, and Si iii respectively.
Conclusions. The light curve simulations imply a power law exponent greater
than the critical value of 2 for all ion species. This implies that if the
energy of flare-like events is extrapolated to low energies, nanoflares could
provide a significant contribution to the heating of active region coronae.Comment: 4 pages, 5 figure
Spodoptera cosmioides (Lepidoptera: Noctuidae) in Brazil: spatial distribution and relationship in the S. latifascia species group.
Spodoptera cosmioides (Walker, 1858) is an economically relevant polyphagous moth, widely distributed in the Neotropics and part of the Spodoptera latifascia (Walker, 1856) species group. In this study, we used extensive sampling from different regions to describe the spatial distribution of S. cosmioides in Brazil and evaluate its variability both from morphological and molecular perspectives. Variable coloration and several morphological similarities were found among S. cosmioides and congeners of the S. latifascia complex, diverging from each 0.5 to 3.5% of mitochondrial DNA. The genetic divergence at the species level of S. cosmioides was 0.5% throughout Brazil, and a geographic structure was absent, including shared haplotypes with S. descoinsi Lalanne-Cassou & Silvain, 1994. Spodoptera cosmioides was found in all six biomes of Brazil, with the highest abundance recorded in the Cerrado, followed by the Amazon, Atlantic Rainforest, Caatinga, Pantanal, and Pampa
Registro da ocorrência de Helicoverpa armigera no Rio Grande do Sul, Brasil.
A presença de Helicoverpa armigera (Lepidoptera: Noctuidae: Heliothinae) no Brasil foi confirmada pela primeira vez na região do Cerrado (oeste da Bahia, Goiás e Mato Grosso) no início de 2013, por C. Czepak e colaboradores. Em seguida, A. Specht e colaboradores ampliaram o registro para outros estados, incluindo o Paraná. Admite-se que este inseto estava presente no país há mais tempo, causando severos danos às culturas agrícolas, principalmente em soja, algodão, milho e tomate industrial. No estado do Rio Grande do Sul, o problema veio à tona na safra 2012/13, quando técnicos e produtores se depararam com infestações elevadas e com a dificuldade de controle das lagartas na cultura da soja. Lagartas coletadas em lavouras de soja foram criadas em laboratório na FAMV/UPF e na Embrapa Trigo, em Passo Fundo. Das mariposas obtidas em laboratório, amostras provenientes de lagartas coletadas nos dias 20 e 21 de dezembro de 2012 em lavouras de soja localizadas dos municípios de Passo Fundo e Espumoso e de lagartas coletadas em soja no dia 22 de maio de 2013, em Carazinho, foram encaminhadas ao terceiro autor, taxonomista deste grupo de insetos, que confirmou a identidade específica de H. armigera. Os resultados foram relatados ao Ministério da Agricultura, Pecuária e Abastecimento, que os considerou válidos como registro de ocorrência de H. armigera no Estado, através de comunicado aos autores no dia 19 de novembro de 2013. Na safra 2013/14, adultos foram coletados em armadilhas de feromônio sexual, em outubro. Lagartas grandes (5º e 6º instares) foram encontradas em trigo alimentando-se dos grãos em massa ou secos, além de canola e milho. A incidência maior foi em soja, desde os estádios iniciais (novembro) até a época de colheita (março). A ocorrência de adultos e de lagartas em várias localidades e regiões sugere que a espécie está amplamente distribuída no Rio Grande do Sul
Photon-Photon Entanglement with a Single Trapped Atom
An experiment is performed where a single rubidium atom trapped within a
high-finesse optical cavity emits two independently triggered entangled
photons. The entanglement is mediated by the atom and is characterized both by
a Bell inequality violation of S=2.5, as well as full quantum-state tomography,
resulting in a fidelity exceeding F=90%. The combination of cavity-QED and
trapped atom techniques makes our protocol inherently deterministic - an
essential step for the generation of scalable entanglement between the nodes of
a distributed quantum network.Comment: 5 pages, 4 figure
Spodoptera frugiperda (Lepidoptera: Noctuidae) updated host plants and new records.
Conteúdo do volume 2: Ácaros; Biologia, fisiologia, morfologia; Controle biológico com bactérias entomopatogênicas; Controle biológico com fungos entomopatológicos; Controle biológico com nematoides; Controle biológico com parasitoides; Controle biológico com predadores; Ecologia e biodiversidade; Educação e etnoentomologia; Entomologia florestal; Entomologia Forense; Entomologia médica e veterinária; Entomologia molecular; Manejo integrado de pragas; Organismos geneticamente modificados; Plantas inseticidas; Polinização; Pragas quarentenárias e invasivas; Resistência de insetos a táticas de controle; Resistência de plantas a insetos; Semioquímicos e comportamento; Sistemática e taxonomia; Tecnologia de aplicação; Controle biológico com vírus entomopatogênicos; Controle químico
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