426 research outputs found
Quantifying fusion born ion populations in magnetically confined plasmas using ion cyclotron emission
Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the
fusion born alpha-particle population in magnetically confined plasmas.
Pioneering observations from JET and TFTR found that ICE intensity
scales approximately linearly with the measured neutron flux from fusion
reactions, and with the inferred concentration, , of fusion-born
alpha-particles confined within the plasma. We present fully nonlinear
self-consistent kinetic simulations that reproduce this scaling for the first
time. This resolves a longstanding question in the physics of fusion
alpha-particle confinement and stability in MCF plasmas. It confirms the
magnetoacoustic cyclotron instability (MCI) as the likely emission mechanism
and greatly strengthens the basis for diagnostic exploitation of ICE in future
burning plasmas
Caracterizacion sintomatologica y molecular del virus de la mancha anillada del papayo (PRSV) que infecta Carica papaya L. en el norte del Peru
The objective of present study was symptomatic and molecular characterization of the virus that infects Carica papaya L. in areas of northern Peru. To do this, of different fields were collected leaves of C. papaya with mosaic symptoms, chlorosis and distortion the leaf. Sap of these leaves was inoculated mechanically onto virus-free plants of C. papaya, Chenopodium murale, Ch. amaranticolor, Ch. quinoa, Cucumis melo, C. sativus and Cucurbita pepo; which they were kept at room temperature for 45 days, after which young leaves in of C. papaya, mosaic, distortion and reduction of the leaf blade was observed; in the species C. melo, C. sativus and Cucurbita pepo systemic chlorosis. Ch. murale, Ch. amaranticolor and Ch. quinoa they no showed symptoms evident. The plants infected were analyzed by serological technique NCM-ELISA and RT-PCR proving that the virus that is infecting the plantations assessed in the north of Peru, it is the papaya ringspot virus (RSVP).El presente trabajo tuvo como objetivo la caracterización sintomatológica y molecular del virus que infecta Carica papaya L. en zonas del norte peruano. Para ello, de diferentes campos en producción se colectaron hojas tiernas de C. papaya con síntomas de mosaico, clorosis, aclareo de nervaduras y distorsión de la lámina foliar. Savia de estas hojas fue inoculada en forma mecánica sobre plantas libres de virus de C. papaya, Chenopodium murale, Ch. amaranticolor, Ch. quinoa, Cucumis melo, C. sativus y Cucurbita pepo; las que fueron mantenidas a temperatura ambiente durante 45 días al cabo de los cuales en las hojas jóvenes de C. papaya se observó aclareo de nervaduras, mosaico, distorsión y reducción de la lámina foliar; en las especies C. melo, C. sativus y Cucurbita pepo clorosis sistémica, en Ch. murale, Ch. amaranticolor y Ch. quinoa no se evidenciaron sintomas. Las plantas de C. papaya, C. melo, C. sativus y Cucurbita pepo infectadas, fueron analizadas por la técnica serológica de NCM-ELISA y RT-PCR comprobándose que el virus que se encuentra infectando las plantaciones de las zonas evaluadas en el norte del Perú, es el virus de la mancha anillada del papayo (PRSV)
cloud property retrieval using synergistic AATSR and MERIS observations
A newly developed daytime cloud property retrieval algorithm FAME-C (Freie
Universität Berlin AATSR MERIS Cloud) is presented. Synergistic observations
from AATSR and MERIS, both mounted on the polar orbiting satellite ENVISAT,
are used for cloud screening. For cloudy pixels two main steps are carried out
in a sequential form. First, a micro-physical cloud property retrieval is
performed using an AATSR near-infrared and visible channel. Cloud phase, cloud
optical thickness, and effective radius are retrieved, and subsequently cloud
water path is computed. Second, two independent cloud top height products are
retrieved. For cloud top temperature AATSR brightness temperatures are used,
while for cloud top pressure the MERIS oxygen-A absorption channel is used.
Results from the micro-physical retrieval serve as input for the two cloud top
height retrievals. Introduced are the AATSR and MERIS forward models and
auxiliary data needed in FAME-C. Also, the optimal estimation method with
uncertainty estimates, which also provides for uncertainty estimated of the
retrieved property on a pixel-basis, is presented. Within the frame of the ESA
Climate Change Initiative project first global cloud property retrievals have
been conducted for the years 2007–2009. For this time period verification
efforts are presented comparing FAME-C cloud micro-physical properties to
MODIS-TERRA derived cloud micro-physical properties for four selected regions
on the globe. The results show reasonable accuracies between the cloud micro-
physical retrievals. Biases are generally smallest for marine stratocumulus
clouds; −0.28, 0.41μm and −0.18 g m−2 for cloud optical thickness, effective
radius and cloud water path, respectively. This is also true for the root mean
square error. Also, both cloud top height products are compared to cloud top
heights derived from ground-based cloud radars located at several ARM sites.
FAME-C mostly shows an underestimation of cloud top heights when compared to
radar observations, which is partly attributed to the difficulty of accurate
cloud property retrievals for optically thin clouds and multi-layer clouds.
The bias is smallest, −0.9 km, for AATSR derived cloud top heights for single-
layer clouds
Structure of Polyelectrolytes in Poor Solvent
We present simulations on charged polymers in poor solvent. First we
investigate in detail the dilute concentration range with and without imposed
extension constraints. The resulting necklace polymer conformations are
analyzed in detail. We find strong fluctuations in the number of pearls and
their sizes leading only to small signatures in the form factor and the
force-extension relation. The scaling of the peak in the structure factor with
the monomer density shows a pertinent different behavior from good solvent
chains.Comment: 7 pages, 5 figures. submitted to EP
Like-charge attraction through hydrodynamic interaction
We demonstrate that the attractive interaction measured between like-charged
colloidal spheres near a wall can be accounted for by a nonequilibrium
hydrodynamic effect. We present both analytical results and Brownian dynamics
simulations which quantitatively capture the one-wall experiments of Larsen and
Grier (Nature 385, p. 230, 1997).Comment: 10 pages, 4 figure
Caracterização morfobiológica, morfométrica e ultraestrutural de isolados silvestres de Trypanosoma cruzi do estado do Rio de Janeiro, Brasil
Triatoma vitticeps is a triatomine with geographic distribution restrict to Brazil, which exhibits high prevalence of Trypanosoma cruzi natural infection. Of special epidemiologic concern, this species often invades households in the states of Rio de Janeiro, Minas Gerais and Espirito Santo. The objective of this study was to evaluate morphological and ultrastructural parameters on three T. cruzi isolates obtained from wild T. vitticeps specimens. The growth and cell differentiation of the parasite was evaluated through epimastigote and trypomastigote forms obtained in the growth curves for three distinct isolates. The maximum growth showed differences at the 20th day of the curve. Our in vitro results show a heterogeneity, regarding these features for samples cultivated under the same conditions. Morphometric analyzes based on the shape of epimastigotes and trypomastigotes corroborated such differentiation. These results highlight the need of better understanding the meaning of this diversity under an eco-epidemiological perspective792294303COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJTriatoma vitticeps é um triatomíneo com distribuição geográfica restrita ao território brasileiro, apresentando alta prevalência de infecção natural pelo Trypanosoma cruzi. Esta espécie é relevante sob o ponto de vista epidemiológico por invadir domicílios com frequência nos estados do Rio de Janeiro, Minas Gerais e Espírito Santo. O objetivo deste estudo foi avaliar parâmetros morfológicos e ultraestruturais, em três isolados de T. cruzi obtidos a partir de triatomíneos silvestres. O crescimento e a diferenciação celular do parasita foi avaliado através das formas epimastigotas e tripomastigotas obtidas nas curvas de crescimento para os três isolados. O crescimento máximo mostrou diferenças no 20º dia da curva. Nossos resultados in vitro mostram uma heterogeneidade, em relação a essas características para amostras cultivadas nas mesmas condições. As análises morfométricas baseadas na conformação de epimastigotas e trypomastigotes corroboraram essa diferenciação. Estes resultados ressaltam a necessidade de uma melhor compreensão do significado desta diversidade sob uma perspectiva eco-epidemiológicaThe authors thank “Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC-FIOCRUZ), Brasi
Neurons along the auditory pathway exhibit a hierarchical organization of prediction error
Perception is characterized by a reciprocal exchange of predictions and prediction error signals between neural regions. However, the relationship between such sensory mismatch responses and hierarchical predictive processing has not yet been demonstrated at the neuronal level in the auditory pathway. We recorded single-neuron activity from different auditory centers in anaesthetized rats and awake mice while animals were played a sequence of sounds, designed to separate the responses due to prediction error from those due to adaptation effects. Here we report that prediction error is organized hierarchically along the central auditory pathway. These prediction error signals are detectable in subcortical regions and increase as the signals move towards auditory cortex, which in turn demonstrates a large-scale mismatch potential. Finally, the predictive activity of single auditory neurons underlies automatic deviance detection at subcortical levels of processing. These results demonstrate that prediction error is a fundamental component of singly auditory neuron responses
Caracterização morfobiológica, morfométrica e ultraestrutural de isolados silvestres de Trypanosoma cruzi do estado do Rio de Janeiro, Brasil
Triatoma vitticeps is a triatomine with geographic distribution restrict to Brazil, which exhibits high prevalence of Trypanosoma cruzi natural infection. Of special epidemiologic concern, this species often invades households in the states of Rio de Janeiro, Minas Gerais and Espírito Santo. The objective of this study was to evaluate morphological and ultrastructural parameters on three T. cruzi isolates obtained from wild T. vitticeps specimens. The growth and cell differentiation of the parasite was evaluated through epimastigote and trypomastigote forms obtained in the growth curves for three distinct isolates. The maximum growth showed differences at the 20th day of the curve. Our in vitro results show a heterogeneity, regarding these features for samples cultivated under the same conditions. Morphometric analyzes based on the shape of epimastigotes and trypomastigotes corroborated such differentiation. These results highlight the need of better understanding the meaning of this diversity under an eco-epidemiological perspective.Fil: Da Silva, C. Santos. Instituto Oswaldo Cruz; Brasil. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Carbajal de la Fuente, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Almeida, C.E.. Universidade Estadual de Campinas; BrasilFil: Gonçalves, T.C.M.. Instituto Oswaldo Cruz; BrasilFil: Dos Santos Mallet, J. Reis. Instituto Oswaldo Cruz; Brasi
Application of non-linear techniques for daily weather data reconstruction and downscaling coarse climate data for local predictions
Downscaling techniques aim at resolving the scale discrepancy between climate change scenarios and the resolution demanded for impact assessments. Requirements for downscaled climate, to be useful for end users, include reliable representation of precipitation intensities, temporal and spatial variability, and physical parameters consistency. This report summarizes the results of the proof of concept phase in the development and testing of a novel data reconstruction method and a downscaling algorithm based on the multiplicative random cascade disaggregation method using rainfall signals at different spatial and temporal resolutions. The Wavelet Transformed-based Multi-Resolution Analysis (WT-MRA) was used for reconstructing the historical daily rainfall data needed as input for the downscaling methodology, using satellite-derived proxy data. Comparisons with presently used software showed that in all the cases; that is, the reconstructed, generated daily or downscaled daily data, the products developed outperformed the control test by either generating more accurate outcomes or by demanding significantly less parameterizing data
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