1,022 research outputs found
Paper-based Mixed Reality Sketch Augmentation as a Conceptual Design Support Tool
This undergraduate student paper explores usage of mixed reality techniques as support tools for conceptual design. A proof-of-concept was developed to illustrate this principle. Using this as an example, a small group of designers was interviewed to determine their views on the use of this technology. These interviews are the main contribution of this paper. Several interesting applications were determined, suggesting possible usage in a wide range of domains. Paper-based sketching, mixed reality and sketch augmentation techniques complement each other, and the combination results in a highly intuitive interface
Spatially Variable Reaction In The Formation Of Anodically Grown Porous Silicon Structures
In porous silicon formations there is an increase of dissolution rate at the fluorine-covered sites of the silicon surface due to the presence of excess electrons coming from oxidation of molecular hydrogen at the passivated (hydrogen-covered) sites. The dissolution rate increase in the presence of excess charge at the fluorine-covered sites is experimentally measured and a theoretical investigation is carried out by a semiempirical Hartree-Fock calculation. This spatially variable dissolution generates the porous silicon surface. © 1995 American Institute of Physics.78159059
Tributyltin in crustacean tissues: Analytical performance and validation of method
The hermit crab Clibanarius vittatus is a typical organism from intertidal regions being considered as a good bioindicator of tributyltin presence at these environments. Thus this study presents the analytical performance and validation method for TBT quantification in tissues of C. vittatus by gas chromatography with pulsed flame photometric detector (GC-PFPD) after extraction with an apolar solvent (toluene) and Grignard derivatization. The limits of detection of the method (LOD) were 2.0 and 2.8 ng g -1 for TBT and DBT (dibutyltin), respectively, and its limits of quantification (LOQ) were 6.6 and 8.9 ng g-1 for TBT and DBT, respectively. The method was applied to samples from Santos Estuary, SĂŁo Paulo State, Brazil. TBT and DBT concentrations ranged from 26.7 to 175.0 ng g -1 and from 46.2 to 156.0 ng g -1, respectively. These concentrations are worrisome since toxic effects (such as endocrine disruption) have been reported for other organisms even under lower levels of registred at this study. © 2012 Sociedade Brasileira de QuĂmica
Frequency and damping of hydrodynamic modes in a trapped Bose-condensed gas
Recently it was shown that the Landau-Khalatnikov two-fluid hydrodynamics
describes the collision-dominated region of a trapped Bose condensate
interacting with a thermal cloud. We use these equations to discuss the low
frequency hydrodynamic collective modes in a trapped Bose gas at finite
temperatures. We derive a variational expressions based on these equations for
both the frequency and damping of collective modes. A new feature is our use of
frequency-dependent transport coefficients, which produce a natural cutoff by
eliminating the collisionless low-density tail of the thermal cloud. Above the
superfluid transition, our expression for the damping in trapped inhomogeneous
gases is analogous to the result first obtained by Landau and Lifshitz for
uniform classical fluids. We also use the moment method to discuss the
crossover from the collisionless to the hydrodynamic region. Recent data for
the monopole-quadrupole mode in the hydrodynamic region of a trapped gas of
metastable He is discussed. We also present calculations for the damping of
the analogous monopole-quadrupole condensate mode in the superfluid
phase.Comment: 22 pages, 10 figures, submitted to Physical Review
Imbalance of naive and memory T lymphocytes with sustained high cellular activation during the first year of life from uninfected children born to HIV-1-infected mothers on HAART
The immune consequences of in utero HIV exposure to uninfected children whose mothers were submitted to highly active antiretroviral therapy (HAART) during gestation are not well defined. We evaluated 45 HIV-exposed uninfected (ENI) neonates and 45 healthy unexposed control (CT) neonates. All HIV-infected mothers received HAART during pregnancy, and the viral load at delivery was <50 copies/mL for 56.8%. Twenty-three ENI neonates were further evaluated after 12 months and compared to 23 unexposed healthy age-matched infants. Immunophenotyping was performed by flow cytometry in cord and peripheral blood. Cord blood lymphocyte numbers did not differ between groups. However, ENI neonates had a lower percentage of naive T cells than CT neonates (CD4+, 76.6 vs 83.1%, P < 0.001; CD8+, 70.9 vs 79.6%, P = 0.003) and higher percentages of central memory T cells than CT neonates (CD4+, 13.9 vs 8.7%, P < 0.001; CD8+, 8.6 vs 4.8%, P = 0.001). CD38 mean fluorescence intensity of T cells was higher in ENI neonates (CD4+, 62.2 vs 52.1, P = 0.007; CD8+, 47.7 vs 35.3, P < 0.001). At 12 months, ENI infants still had higher mean fluorescence intensity of CD38 on T cells (CD4+, 34.2 vs 23.3, P < 0.001; CD8+, 26.8 vs 19.4, P = 0.035). Despite effective maternal virologic control at delivery, HIV-exposed uninfected children were born with lower levels of naive T cells. Immune activation was present at birth and remained until at least 12 months of age, suggesting that in utero exposure to HIV causes subtle immune abnormalities.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES
Mean field effects in a trapped classical gas
In this article, we investigate mean field effects for a bosonic gas
harmonically trapped above the transition temperature in the collisionless
regime. We point out that those effects can play also a role in low dimensional
system. Our treatment relies on the Boltzmann equation with the inclusion of
the mean field term.
The equilibrium state is first discussed. The dispersion relation for
collective oscillations (monopole, quadrupole, dipole modes) is then derived.
In particular, our treatment gives the frequency of the monopole mode in an
isotropic and harmonic trap in the presence of mean field in all dimensions.Comment: 4 pages, no figure submitted to Phys. Rev.
Studies on the mineral nutrition of rice: XXIII. Evaluation of the nutritional status of cv. L-45
Rice plants were grown in complete and deficient nutrient solutions, with respect to macronutrients. Growth was affected by lack of N, P and Mg only. The concentration of the elements in dry matter, however, was affected by the treatments. Both leaf analyses and quick tissue tests showed to be adequate to show variations in mineral composition in response to the omission of either N, P on K from the substrate. Foliar nitrate reductase activity decreased when any element, except Ca (increase) was lacking.O arroz de sequeiro, cv. L-45, foi cultivado em solução nutritiva contendo todos os macro e micronutrientes e com omissĂŁo dos primeiros, um de cada vez. A falta dos elementos no substrato afetou o crescimento na seguinte ordem crescente: nitrogĂȘnio, fĂłsforo e magnĂ©sio. NĂŁo se notou influĂȘncia da omissĂŁo dos demais na produção de matĂ©ria seca, embora tivesse havido diminuição no teor do elemento na planta quando o mesmo foi fornecido em concentração menor na solução. Verificou-se atravĂ©s da diagnose foliar redução no teor de N, P e K quando os mesmos se achavam deficientes. Resultado anĂĄlogo foi obtido ao se fazer teste rĂĄpido (spot teste) para nitrato, fosfato e potĂĄsio solĂșvel no tecido foliar. A atividade da redutase de nitrato foliar diminuiu como conseqĂŒĂȘncia de todos os tratamentos, exceto o menos Ca, ca so em que aumentou significativamente
Chemical composition and toxicity of essential oils of Piper spp. against larvae of Aedes aegypti L. (Diptera: Culicidae)
Aedes aegypti L. Ă© um dos vetores do dengue. No Brasil, tem ganhado muita atenção no setor da saĂșde pĂșblica, uma vez que esta doença tem se tornando mais agressiva na forma hemorrĂĄgica na popula- ção. Esse estudo teve como objetivo investigar o efeito de Ăłleos essenciais de Piper aduncum, Piper marginatum e Piper nigrum contra larvas de Aedes aegypti. Em um esforço para encontrar uma maneira natural, eficaz e acessĂvel para controlar esta doença endĂȘmica, as atividades dos Ăłleos essenciais, a partir das plantas, foram analisadas por comparação atravĂ©s da medida da CL50 . Os Ăłleos essenciais obtidos por hidrodestilação foram analisados por CG/EM. Os principais componentes identificados foram: ÎČ-pineno (32,7%) e E-cariofileno (17,1%) em P. aduncum; isoelemecina (21,7%) e apiol (20,1%) em P. marginatum e E-cariofileno (24,2%) e Ăxido-cariofileno (20,1%) em P. nigrum. Os resultados mostram que Piper marginatum apresentou CL50 de 8,29 ÎŒg/mL e este trabalho Ă© o primeiro relato de atividade larvicida de P. aduncum. Estes resultados sugerem que os Ăłleos essenciais de espĂ©cies do gĂȘnero Piper sĂŁo promissores como larvicidas contra larvas de A. aegypti.Aedes aegypti L. is one of the vectors of dengue fever. In Brazil it has gain much attention in the Public Health sector since this disease has becoming more aggressive in the hemorrhagic form in the population. This study aimed to investigate the effect of Piper aduncum, Piper marginatum and Piper nigrum essential oils against Aedes aegypti larvae. In an effort to find a natural effective and affordable way to control this endemic disease, the larvicidal activities of essential oils from the plants were analyzed for activity comparison by measurement of their LC50 . The essential oils isolated by hydrodistillation were analyzed by GC/MS. The main components identified were: ÎČ-pinene (32.7%) and E-caryophyllene (17.1%) in P. aduncum; isoelemecin (21.7%) and apiole (20.1%) in P. marginatum and E-caryophyllene (24.2%) and caryophyllene oxide (20.1%) in P. nigrum. The results show that Piper marginatum presented the LC50 of 8.29 ÎŒg/mL and these are the first report about the larvicidal activity of P. aduncum. These results suggest that the essential oil of Piper species are promising as larvicide against A. aegypti larvae.Colegio de FarmacĂ©uticos de la Provincia de Buenos Aire
Ground state and elementary excitations of single and binary Bose-Einstein condensates of trapped dipolar gases
We analyze the ground-state properties and the excitation spectrum of
Bose-Einstein condensates of trapped dipolar particles. First, we consider the
case of a single-component polarized dipolar gas. For this case we discuss the
influence of the trapping geometry on the stability of the condensate as well
as the effects of the dipole-dipole interaction on the excitation spectrum. We
discuss also the ground state and excitations of a gas composed of two
antiparallel dipolar components.Comment: 12 pages, 9 eps figures, final versio
- âŠ