1,256 research outputs found
Methiocarb-Treated Rice Seed Applied After Field Draining Fails to Repel Blackbirds from Sprouting Rice
Blackbirds, primarily Agelaius phoeniceus, cause extensive losses to sprouting rice in southwestern Louisiana. Methiocarb applied to seed prior to planting at rates above 1.0 g a.i./kg rice (0.1%) has provided excellent protection to sprouting rice in Louisiana under conditions of high bird pressure. To reduce treatment costs, some farmers have used over-flights of methiocarb-treated seed applied at low rates to part of the field after draining. This study showed this technique was not efficacious under conditions of high bird pressure. Four fields treated in this manner suffered 98% loss of sprouts compared to 100% loss in four untreated fields. Large flocks of blackbirds ( \u3e 3,000) fed in all treated and untreated fields during the first four days after draining. Blackbirds were evidently able to distinguish between treated (ungerminated) and untreated (germinated) seed. Large feeding flocks of blackbirds were composed almost entirely of females (x = 94%; n = 17); it is not known whether these birds were residents or migrants. We recommend that future studies investigate the efficacy of using mixtures of methiocarb-treated seed and untreated seed at planting time for reducing blackbird damage to sprouting rice.
Blackbirds cause extensive losses to sprouting rice in southwestern Louisiana. Methiocarb applied to rice seed prior to planting at rates above 1.0 g a.i./kg seed provided excellent protection to sprouting rice in Louisiana under conditions of high bird pressure (Holler et al. 1985). Use of methiocarb by growers under emergency (Section 18) exemption from the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) has been low, largely due to the high cost of treating all rice seed used in planting (Holler et al. 1982, 1985).
In 1985 we determined the feasibility of protecting newly planted rice fields from blackbird damage by aerially applying treated seed on the fields upon completion of drainage after planting. This method has been used by farmers in Louisiana and subjective evaluation of its effectivness has been inconclusive. If efficacious, this method would provide the grower with a measure that could be used after planting when bird pressure is known to be high. It would also reduce residues in drainage water and it would result in substantial reduction in the cost of protection. Personnel of the Crowley, Louisiana Field Station, U.S.D.A. (formerly U.S. Fish and Wildlife Service), provided logistical support. A. Wilson, Rice Research Station, Louisiana State University, Crowley, Louisiana collected sprout count data from one field. Mesurol®4/75% Seed Treater for this test was provided by the Mobay Chemical Corporation, Kansas City, Missouri. The study was conducted by the U.S. Fish and Wildlife Service, Department of the Interior. The Animal Damage Control Program, including the Denver Wildlife Research Center, was transferred to USDA-APHIS (Animal and Plant Health Inspection Service) on 3 March 1986
Infraestrutura Nacional de Dados Espaciais: Aspectos Computacionais.
O objetivo deste documento é apresentar os principais conceitos relacionados aos pilares ?tecnologia? e ?padrões?, com enfoque em seus aspectos computacionais. A intenção é sumarizar os fundamentos teóricos envolvidos na especificação da INDE e reunir as principais referências de softwares open source atualmente disponíveis e amplamente adotados pela comunidade para a implantação da INDE.bitstream/item/84963/1/COMUN-TECNICO-1-GESTAO-TERRITORIAL-Infraestrut-Nac-Dados-Espac-ed01-2013.pd
Metodologia de monitoramento de cobertura vegetal: estudo de caso no município de Goiânia, GO.
Este trabalho apresenta uma proposta para a análise da variação da cobertura vegetal, utilizando dados de acesso público. Os procedimentos de análise multitemporal propostos foram aplicados no município de Goiânia, GO, como estudo de caso. Aplicou-se o índice de vegetação por diferença normalizada (NDVI), obtido a partir de imagens Landsat-5, em três anos de referência: 1997, 2004, 2011. Consideraram-se três classes de cobertura: ?corpos d?água?, ?vegetação? e ?outros usos?. Foram utilizadas técnicas de processamento digital de imagens, visando à correção de erros gerados pela influência da atmosfera e à obtenção de uma melhor qualidade espectral dos alvos. Para esse fim, o modelo adotado foi o dark object subtraction (DOS). O resultado mostrou-se satisfatório, considerando-se a disponibilidade dos dados e suas limitações.bitstream/item/84894/1/0000010346-BPD-Cobert-vegetal.pd
Análise Morfométrica de Bacia Hidrográfica: Subsídio à Gestão Territorial Estudo de Caso no Alto e Médio Mamanguape.
Para esta análise, foram criados os mapas da drenagem e hipsométrico, levando em conta que o relevo é um dos aspectos mais importantes deste estudo, pois permite compreender a disposição da drenagem e tem aplicação direta para a gestão territorial. A análise da morfometria utilizou 17 índices morfométricos entre os mais de 50 existentes na literatura, dentre os quais podem-se destacar: fator de forma; índice de circularidade; coeficiente de compacidade; índice de rugosidade; padrão de drenagem; canais de drenagem; amplitude altimétrica; densidade de drenagem; textura topográfica; e coeficiente de manutenção. Com base na análise dos resultados, pode-se concluir que o fator de forma (0,44), o índice de circularidade (0,78), o coeficiente de compacidade (1,12) e o índice de rugosidade (0,72) demonstraram que a bacia hidrográfica em estudo exibe um formato alongado contribuindo, dessa forma, para o processo de escoamento e apresentando, portanto, baixa suscetibilidade à ocorrência de enchentes. Enfim, esses parâmetros podem ser utilizados para comparação entre os diversos tipos de áreas como microbacias, fazendas ou municípios, auxiliando, no monitoramento, análise e gestão territorial.bitstream/item/84896/1/0000010346-BPD-Analise-morfometrica.pd
Derivation of Del180 from sediment core log data\u27 Implications for millennial-scale climate change in the Labrador Sea
Sediment core logs from six sediment cores in the Labrador Sea show millennial-scale climate variability during the last glacial by recording all Heinrich events and several major Dansgaard-Oeschger cycles. The same millennial-scale climate change is documented for surface water δ18O records of Neogloboquadrina pachyderma (left coiled); hence the surface water δ18O record can be derived from sediment core logging by means of multiple linear regression, providing a paleoclimate proxy record at very high temporal resolution (70 years). For the Labrador Sea, sediment core logs contain important information about deepwater current velocities and also reflect the variable input of ice-rafted debris from different sources as inferred from grain-size analysis, the relation of density and P wave velocity, and magnetic susceptibility. For the last glacial, faster deepwater currents, which correspond to highs in sediment physical properties, occurred during iceberg discharge and lasted from several centuries to a few millennia. Those enhanced currents might have contributed to increased production of intermediate waters during times of reduced production of North Atlantic Deep Water. Hudson Strait might have acted as a major supplier of detrital carbonate only during lowered sea level (greater ice extent). During coldest atmospheric temperatures over Greenland, deepwater currents increased during iceberg discharge in the Labrador Sea, then surface water freshened shortly thereafter, while the abrupt atmospheric temperature rise happened after a larger time lag of ≥ 1 kyr. The correlation implies a strong link and common forcing for atmosphere, sea surface, and deep water during the last glacial at millennial timescales but decoupling at orbital timescales
A blind detection of a large, complex, Sunyaev--Zel'dovich structure
We present an interesting Sunyaev-Zel'dovich (SZ) detection in the first of
the Arcminute Microkelvin Imager (AMI) 'blind', degree-square fields to have
been observed down to our target sensitivity of 100{\mu}Jy/beam. In follow-up
deep pointed observations the SZ effect is detected with a maximum peak
decrement greater than 8 \times the thermal noise. No corresponding emission is
visible in the ROSAT all-sky X-ray survey and no cluster is evident in the
Palomar all-sky optical survey. Compared with existing SZ images of distant
clusters, the extent is large (\approx 10') and complex; our analysis favours a
model containing two clusters rather than a single cluster. Our Bayesian
analysis is currently limited to modelling each cluster with an ellipsoidal or
spherical beta-model, which do not do justice to this decrement. Fitting an
ellipsoid to the deeper candidate we find the following. (a) Assuming that the
Evrard et al. (2002) approximation to Press & Schechter (1974) correctly gives
the number density of clusters as a function of mass and redshift, then, in the
search area, the formal Bayesian probability ratio of the AMI detection of this
cluster is 7.9 \times 10^4:1; alternatively assuming Jenkins et al. (2001) as
the true prior, the formal Bayesian probability ratio of detection is 2.1
\times 10^5:1. (b) The cluster mass is MT,200 = 5.5+1.2\times 10^14h-1M\odot.
(c) Abandoning a physical model with num- -1.3 70 ber density prior and instead
simply modelling the SZ decrement using a phenomenological {\beta}-model of
temperature decrement as a function of angular distance, we find a central SZ
temperature decrement of -295+36 {\mu}K - this allows for CMB primary
anisotropies, receiver -15 noise and radio sources. We are unsure if the
cluster system we observe is a merging system or two separate clusters.Comment: accepted MNRAS. 12 pages, 9 figure
Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment
The OLYMPUS collaboration reports on a precision measurement of the
positron-proton to electron-proton elastic cross section ratio, ,
a direct measure of the contribution of hard two-photon exchange to the elastic
cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams
were directed through a hydrogen gas target internal to the DORIS storage ring
at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and
time-of-flight scintillators detected elastically scattered leptons in
coincidence with recoiling protons over a scattering angle range of to . The relative luminosity between the two beam species
was monitored using tracking telescopes of interleaved GEM and MWPC detectors
at , as well as symmetric M{\o}ller/Bhabha calorimeters at
. A total integrated luminosity of 4.5~fb was collected. In
the extraction of , radiative effects were taken into account
using a Monte Carlo generator to simulate the convolutions of internal
bremsstrahlung with experiment-specific conditions such as detector acceptance
and reconstruction efficiency. The resulting values of , presented
here for a wide range of virtual photon polarization ,
are smaller than some hadronic two-photon exchange calculations predict, but
are in reasonable agreement with a subtracted dispersion model and a
phenomenological fit to the form factor data.Comment: 5 pages, 3 figures, 2 table
Elementos de apoio à defesa fitossanitária para potencial entrada de Chilo partellus swinhoe (lepidoptera: pyralidae), praga quarentenária ausente, no Brasil.
Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) é um inseto considerado praga quarentenária ausente (A1) no Brasil (Instrução Normativa MAPA Nº59 de 18/12/2013). Esta mariposa apresenta potencial para atacar vários cultivos, entre eles sorgo, milho, milheto, cana-de-açúcar, arroz e várias gramíneas, entre outras. Trabalhos técnicos no exterior apontam a favorabilidade de vários países da América do Sul, incluindo áreas do território brasileiro, ao estabelecimento do inseto. Nesse sentido medidas de prevenção e de controle devem ser mais bem planejadas, antecipadamente à entrada da praga, para apoiar futuras ações de defesa fitossanitária nacional. Entre os elementos de apoio a essas medidas, citam-se aqueles que congregam, em um único recurso, a maior quantidade de informações sobre as possíveis rotas de ingresso ao território nacional, bem como das regiões onde se concentram os principais cultivos-hospedeiros da praga, onde a sua ocorrência acarretaria maiores danos econômicos e sociais em caso de entrada no país. Este trabalho apresenta a distribuição geográfica, em escala global, de regiões potenciais para o estabelecimento de C. partellus, assim como as regiões brasileiras com maior participação das culturas de milho, sorgo, arroz e cana-de-acúcar, localizando a infraestrutura nacional de defesa já existente para que o planejamento de ações seja efetivo. Foram utilizadas informações das áreas produtoras, de maior concentração de rotas marítimas, terrestres e de fronteiras, assim como localizados postos de vigilância. O cruzamento de informações fez uso de ArcGis 1.0 e foram disponibilizados mapas
Size constancy in bat biosonar?
Perception and encoding of object size is an important feature of sensory systems. In the visual system object size is encoded by the visual angle (visual aperture) on the retina, but the aperture depends on the distance of the object. As object distance is not unambiguously encoded in the visual system, higher computational mechanisms are needed. This phenomenon is termed "size constancy". It is assumed to reflect an automatic re-scaling of visual aperture with perceived object distance. Recently, it was found that in echolocating bats, the 'sonar aperture', i.e., the range of angles from which sound is reflected from an object back to the bat, is unambiguously perceived and neurally encoded. Moreover, it is well known that object distance is accurately perceived and explicitly encoded in bat sonar. Here, we addressed size constancy in bat biosonar, recruiting virtual-object techniques. Bats of the species Phyllostomus discolor learned to discriminate two simple virtual objects that only differed in sonar aperture. Upon successful discrimination, test trials were randomly interspersed using virtual objects that differed in both aperture and distance. It was tested whether the bats spontaneously assigned absolute width information to these objects by combining distance and aperture. The results showed that while the isolated perceptual cues encoding object width, aperture, and distance were all perceptually well resolved by the bats, the animals did not assign absolute width information to the test objects. This lack of sonar size constancy may result from the bats relying on different modalities to extract size information at different distances. Alternatively, it is conceivable that familiarity with a behaviorally relevant, conspicuous object is required for sonar size constancy, as it has been argued for visual size constancy. Based on the current data, it appears that size constancy is not necessarily an essential feature of sonar perception in bats
CD8(+) T cells retain protective functions despite sustained inhibitory receptor expression during Epstein-Barr virus infection in vivo
Epstein Barr virus (EBV) is one of the most ubiquitous human pathogens in the world, persistently infecting more than 90% of the adult human population. It drives some of the strongest human CD8+ T cell responses, which can be observed during symptomatic primary
infection known as infectious mononucleosis (IM). Despite high viral loads and prolonged
CD8+ T cell stimulation during IM, EBV enters latency and is under lifelong immune control
in most individuals that experience this disease. We investigated whether changes in T cell
function, as frequently characterized by PD-1 up-regulation, occur during IM due to the prolonged exposure to high antigen levels. We readily detected the expansion of PD-1 positive
CD8+ T cells together with high frequencies of Tim-3, 2B4, and KLRG1 expression during
IM and in mice with reconstituted human immune system components (huNSG mice) that
had been infected with a high dose of EBV. These PD-1 positive CD8+ T cells, however,
retained proliferation, cytokine production, and cytotoxic abilities. Multiple subsets of CD8+
T cells expanded during EBV infection, including PD-1+
Tim-3+
KLRG1+ cells that express
CXCR5 and TCF-1 germinal center homing and memory markers, and may also contain
BATF3. Moreover, blocking the PD-1 axis compromised EBV specific immune control and
resulted in virus-associated lymphomagenesis. Finally, PD-1+
, Tim-3+
, and KLRG1+ CD8+ T
cell expansion coincided with declining viral loads during low dose EBV infection. These
findings suggest that EBV infection primes PD-1 positive CD8+ T cell populations that rely
on this receptor axis for the efficient immune control of this ubiquitous human tumor virus
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