3,899 research outputs found
Extended Seismic Source Characterisation using Linear Programming Inversion in a Dual Formulation
A linear programming (LP) inversion method in a dual formulation was applied to reconstruct the kinematics of
finite seismic ruptures. In a general setting, this approach can yield results from several data sets: strong ground
motion, teleseismic waveforms or/and geodesic data (static deformation). The dual formulation involves the
transformation of a normal solution space into an equivalent but reduced space: the dual space. The practical
result of this transformation is a simpler inversion problem that is therefore faster to resolve, more stable and
more robust. The developed algorithm includes a forward problem that calculates Green’s functions using a
finite differences method with a 3D structure model. To evaluate the performance of this algorithm, we applied it
to the reconstitution of a realistic slip distribution model from a data set synthesised using this model, i.e., the
solution of the forward problem. Several other standard inversion approaches were applied to the same synthetic
data for comparison
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Optimized Multimode Interference Fiber Based Refractometer in A Reflective Interrogation Scheme
A fiber based refractometer in a reflective interrogation scheme is investigated and optimized. A thin gold film was deposited on the tip of a coreless fiber section, which is spliced with a single mode fiber. The coreless fiber is a multimode waveguide, and the observed effects are due to multimode interference. To investigate and optimize the structure, the multimode part of the sensor is built with 3 different lengths: 58 mm, 29 mm and 17 mm. We use a broadband light source ranging from 1475 nm to 1650 nm and we test the sensors with liquids of varying refractive indices, from 1.333 to 1.438. Our results show that for a fixed wavelength, the sensor sensitivity is independent of the multimode fiber length, but we observed a sensitivity increase of approximately 0.7 nm/RIU for a one-nanometer increase in wavelength
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Enhancing the Sensitivity of SMS Fiber Sensors by the Use of High Refractive Index Coatings
This paper presents a study on the behavior of single-mode/multimode/single-mode sensors with diamond-like carbon coating of high refractive index. Spectra and response for different values of the external medium refractive index are recorded and analyzed
Two Superconducting Phases in CeRh_1-xIr_xIn_5
Pressure studies of CeRh_1-xIr_xIn_5 indicate two superconducting phases as a
function of x, one with T_c >= 2 K for x < 0.9 and the other with T_c < 1.2 K
for x > 0.9. The higher T_c phase, phase-1, emerges in proximity to an
antiferromagnetic quantum-critical point; whereas, Cooper pairing in the lower
T_c phase-2 is inferred to arise from fluctuations of a yet to be found
magnetic state. The T-x-P phase diagram of CeRh_1-xIr_xIn_5, though
qualitatively similar, is distinctly different from that of
CeCu_2(Si_1-xGe_x)_2.Comment: 5 pages, 3 figure
Wood consumption and pellet production by Azorean Kalotermitidae: Kalotermes flavicollis and Cryptotermes brevis
Existem nos Açores duas espécies de térmitas da família Kalotermitidae: a Kalotermes flavicollis é uma térmita de madeira verde e é uma praga urbana menor. A Cryptotermes brevis é uma térmita de madeira seca e é uma importante praga para mobiliário e estruturas. São analisadas as espécies de madeira consumidas por cada espécie nos Açores sendo descritas diferenças na cor, tamanho, forma, e modo de despejo das partículas fecais. A taxa de consumo de madeira e a produção de partículas fecais para a espécie Cryptotermes brevis foram estudadas em 49 tipos diferentes de madeiras. Verificou-se que duas espécies de madeira produzidas localmente e muito usadas na construção, Cryptomeria japonica e Eucalyptus sp., foram das mais consumidas, indicando a importância do desenvolvimento de um sistema local para tratamento por pressão em autoclave das madeiras. Entre as madeiras menos consumidas (mais resistentes) encontram-se espécies tropicais, como o Jatobá e a Maçaranduba. As partículas fecais que são expulsas das galerias pelas térmitas são a forma mais conspícua de detectar infestações por Cryptotermes brevis, dando bons meios para monitorizar a localização de térmitas, o tamanho da colónia e a sua actividade. Foi verificado que a expulsão de partículas fecais é descontínua. Contudo, alguns períodos de expulsão de partículas fecais são contínuos por alguns dias, com taxas de expulsões de 274 partículas fecais, por hora, com acumulações de até 7,8 gramas num período de duas semanas.ABSTRACT: Two termite species of the family Kalotermitidae occur in the Azores: Kalotermes flavicollis is a dampwood termite and minor house pest. Cryptotermes brevis is a dry wood termite and a major pest of furniture and structures. Records of wood species consumed by each species in the Azores are reviewed. Differences in the color, size, shape, disposal of fecal pellets of each species are described. Rates of wood consumption, pellet production were experimentally studied for Cryptotermes brevis on 49 different wood species. Two wood species that are locally produced and widely utilized for construction, Cryptomeria japonica and Eucalyptus sp., were found to be among the most preferred woods for termite consumption indicating an important need for the development of an effective local pressure treatment system for preserving these woods. Least preferred (most resistant woods) included tropical hardwood species such as Jatobá and Maçaranduba. Fecal pellets expelled from galleries by termites are the most conspicuous evidence of Cryptotermes brevis infestations and provide a potential means of monitoring termite location, colony size and activity. Pellet expulsion was found to be discontinuous. However some bouts of pellet dumping were observed to be continuous for at least several days with rates of pellet expulsion of up to 274 pellets per hour, with pellet accumulations of as much as 7.8 grams over a two-week period
Evolution of density perturbations in decaying vacuum cosmology: The case of non-zero perturbations in the cosmological term
We extend the results of a previous paper where a model of interacting dark
energy, with a cosmological term decaying linearly with the Hubble parameter,
is tested against the observed mass power spectrum. In spite of the agreement
with observations of type Ia supernovas, baryonic acoustic oscillations and the
cosmic microwave background, we had shown previously that no good concordance
is achieved if we include the mass power spectrum. However, our analysis was
based on the ad hoc assumption that the interacting cosmological term is
strictly homogeneous. Now we perform a more complete analysis, by perturbing
such a term. Although our conclusions are still based on a particular, scale
invariant choice of the primordial spectrum of dark energy perturbations, we
show that a cosmological term decaying linearly with the Hubble parameter is
indeed disfavored as compared to the standard model.Comment: Version accepted for publication in Physical Review
Gastric Antral Vascular Ectasia (GAVE) and Hereditary Hemorrhagic Telangiectasia (HHT): Two Different Conditions, One Treatment
info:eu-repo/semantics/publishedVersio
Treatment of Cryptotermes brevis infestations in furniture with heat, solid fumigants and inert gases
A Cryptotermes brevis é uma térmita extraordinária na sua capacidade única de atacar madeira extremamente seca. É, igualmente, extraordinária na capacidade de atacar uma grande variedade de tipos de madeira, o que nos leva a concluir como sendo a única espécie de térmitas que é facilmente encontrada em mobílias. Como tal, é muito fácil a sua dispersão aquando do transporte de mobílias infestadas, de lugar para lugar, e esta é uma das principais razões pela qual esta térmita consegue ter uma distribuição tão ampla em áreas urbanas, em praticamente todo mundo. É muito provável que a sua introdução nos Açores tenha sido através de mobília infestada e que a dispersão contínua que se tem verificado de cidade para cidade seja devido a essa razão. Ou seja, o tratamento de mobílias é uma componente importante de um programa integrado para lidar com o controlo e contenção desta espécie de térmita. O objectivo deste trabalho é apresentar os resultados obtidos de três tipos de experiências para tratamento de mobílias infestadas com a Cryptotermis brevis. A primeira experiência consistiu num método muito simples, envolvendo o selar de um objecto infestado dentro de um saco de plástico preto, sendo este colocado num local fora do laboratório, a fim de se encontrar em plena exposição solar durante o mês de Agosto. O método seguinte consistiu em selar um objecto infestado num recipiente com um de três tipos de fumigantes sólidos: bolas de naftalina, para-dichlorobenzeno ou dichlorvos (Vapona®). O último método envolveu um teste de anóxia, em que um de três tipos de gases inertes, azoto (N2), dióxido de carbono (CO2) ou árgon (Ar), foi usado para substituir o ar existente dentro de um saco plástico (bolha) selado, contendo um objecto infestado.ABSTRACT: Cryptotermis brevis is an extraordinary termite in its unique ability to attack extremely dry wood. It is also unique in its ability to attack a wide variety of wood species. This leads to it being one of the only termites in the world which is commonly found attacking furniture. As such, it is easily moved when people move their furniture from place to place and this is one of the reasons why this termite has become widely dispersed to urban areas around the world. It is very likely it was first introduced into the Azores with furniture and that its continued dispersal from island to island and town to town will be by the further movement of infested furniture. Therefore furniture treatment is an important component of an integrated program for dealing with the control and containment of this pest species. The objective of this presentation is to explain the results of three types of experimental furniture treatment that we conducted. The first of these was a simple method involving the sealing of an infested item inside a black plastic bag which was then placed in full sun exposure outdoors during the month of August. The next method involved sealing an infested item in a container with one of three solid fumigants: naphthalene (moth balls), para-dichlorobenzene (PDB moth balls), or dichlorvos (Vapona®). The final method involved anoxia test in which one of three inert gases, either nitrogen (N2), carbon dioxide (CO2), or argon (Air) gases were used to displace the air in a sealed bag holding an infested item
Flight and colony foundation of Azorean termites with emphasis on Cryptotermes brevis
Cada uma das três espécies de térmitas existentes no arquipélago açoriano apresenta um comportamento de voo em momentos distintos ao longo do dia e ao longo do ano. A Cryptotermes brevis tem o seu período de dispersão (de voo) entre os meses de Junho e Agosto no crepúsculo vespertino, a Kalotermes flavicollis de Setembro a Outubro, durante a tarde, e a Reticulitermes grassei tem o seu período de enxameamento na Primavera, durante a manhã. Das espécies referidas, a que apresenta maior importância, por constituir uma praga de dimensões consideráveis em algumas das ilhas, é a C. brevis, a única que tem um comportamento de voo nocturno, tornando, assim, possível o uso de armadilhas luminosas. As experiências aqui apresentadas contêm vários testes com diferentes tipos de luzes, fluorescentes e incandescentes, diferentes cores de armadilhas pegajosas, bem como diferentes tipos de colas e fitas colantes. Após o período de voo, as térmitas exibem uma sequência de comportamentos que foram observados e analisados. Foi estudado o tempo para cada um dos seguintes padrões de comportamento: libertação das asas, comportamento de procura (de um parceiro), formação de pares, selagem da câmara de reprodução (ou ninho), amputação das antenas, início da deposição de ovos e tempo até à primeira eclosão. A preferência por buracos de diferentes diâmetros e diferentes espécies de madeira foi também estudada, assim como a produção de ovos e as taxas de sobrevivência e de produção dos mesmos.ABSTRACT: Each of the three Azorean termite species flies during a different season and different time of the day. Cryptotermes brevis flies from June to August, at dusk; Kalotermes flavicollis flies from September to October, in the afternoon; and Reticulitermes grassei flies during the spring, probably during the morning hours. C. brevis is the most important pest and the only one that flies at night, therefore light trapping is possible. Experiments were conducted with fluorescent and incandescent lights, different colours of sticky traps and different kinds of glue or tape. Following the dispersal flight, the termite exhibits a sequence of behaviours which were observed and analysed. The timing of the follow behavioural events was studied: de-alation, searching behaviour, tandem running, sealing the copulation, de-antennation, commencement of oviposition and time to first hatch. Hole size and wood species preferences for colony establishment were also investigated. In addition, egg production and colony survival rates on different woods were studied
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