Von Bezold assimilation effect reverses in stereoscopic conditions

Lightness contrast and lightness assimilation are opposite phenomena: in contrast, grey targets appear darker when bordering bright surfaces (inducers) rather than dark ones; in assimilation, the opposite occurs. The question is: which visual process favours the occurrence of one phenomenon over the other? Researchers provided three answers to this question. The first asserts that both phenomena are caused by peripheral processes; the second attributes their occurrence to central processes; and the third claims that contrast involves central processes, whilst assimilation involves peripheral ones. To test these hypotheses, an experiment on an IT system equipped with goggles for stereo vision was run. Observers were asked to evaluate the lightness of a grey target, and two variables were systematically manipulated: (i) the apparent distance of the inducers; and (ii) brightness of the inducers. The retinal stimulation was kept constant throughout, so that the peripheral processes remained the same. The results show that the lightness of the target depends on both variables. As the retinal stimulation was kept constant, we conclude that central mechanisms are involved in both lightness contrast and lightness assimilation

A proteção efetiva proporcionada à indústria brasileira pelos custos de transporte e pelas tarifas

Os custos de transporte protegem a indústria doméstica contra a competição externa, do mesmo modo que as barreiras "artificiais" representadas pelas tarifas, quotas, lei de similaridade etc

Biologia y perspectiva de microorganismos endófitos asociados a plantas

The endophyte bacteria inhabit plant tissues mainly in intercellular spaces, rarely in intracellular spaces and inside vascular tissues without causing symptoms of disease in plants. Debates on the origin of the endophyte bacteria and the form of penetration, besides the colonization mechanisms, consider the hypothesis that they were originated from seeds, microflora rizosphere of“phylloplane” or material used for plant propagation. The penetration in the plant might take place by stomas, wounds, emergence areas in lateral roots, allowing these bacteria to produce hydrolytic enzymes able to degrade the vegetables cell wall. Recent molecular studies on the diversity of endophyte bacteria have revealed a high affluence of phylotypes promoting the plant growth, suppressing phytopathogens, helping to remove contaminants, dissolving phosphate and contributing to the biological nitrogen assimilation. The objective of this review is to show the evolution, ecology, diversity, function and physiological and molecular techniques for the isolation of endophyte bacteria associated with plant tissuesLas bacterias endófitas residen en tejidos de las plantas, principalmente espacios intercelulares, raramente en espacios intracelulares y dentro de tejidos vasculares sin causar síntomas de enfermedad en la planta. Las discusiones sobre el origen de las bacterias endófitas y la forma de penetración, además de los mecanismos de colonización, consideran la hipótesis de que se originaron desde semillas, de la rizosfera, de microflora de filoplano o de material utilizado para la propagación vegetativa. La penetración en la planta puede ocurrir por estomas, heridas, áreas de emergencia de raíces laterales, siendo que estas bacterias pueden producir enzimas hidrolíticas capaces de degradar la pared celular de los vegetales. Estudios moleculares reciente sobre diversidad de bacterias endófitas han revelado una alta riqueza de filotipos, que promueven el crecimiento de las planta, suprimen fitopatógenos, ayudan a remover contaminantes, solubilizan fosfato y contribuyen a la asimilación biológica de nitrógeno. El objetivo de esta revisión es dar a conocer la evolución, ecología, diversidad, funcionalidad y técnicas fisiológicas y moleculares para el aislamiento de bacterias endófitas asociadas a tejidos de plantas

The Dirichlet-to-Robin Transform

A simple transformation converts a solution of a partial differential equation with a Dirichlet boundary condition to a function satisfying a Robin (generalized Neumann) condition. In the simplest cases this observation enables the exact construction of the Green functions for the wave, heat, and Schrodinger problems with a Robin boundary condition. The resulting physical picture is that the field can exchange energy with the boundary, and a delayed reflection from the boundary results. In more general situations the method allows at least approximate and local construction of the appropriate reflected solutions, and hence a "classical path" analysis of the Green functions and the associated spectral information. By this method we solve the wave equation on an interval with one Robin and one Dirichlet endpoint, and thence derive several variants of a Gutzwiller-type expansion for the density of eigenvalues. The variants are consistent except for an interesting subtlety of distributional convergence that affects only the neighborhood of zero in the frequency variable.Comment: 31 pages, 5 figures; RevTe

Modeling and characterization of the SPIDER half-wave plate

Spider is a balloon-borne array of six telescopes that will observe the Cosmic Microwave Background. The 2624 antenna-coupled bolometers in the instrument will make a polarization map of the CMB with approximately one-half degree resolution at 145 GHz. Polarization modulation is achieved via a cryogenic sapphire half-wave plate (HWP) skyward of the primary optic. We have measured millimeter-wave transmission spectra of the sapphire at room and cryogenic temperatures. The spectra are consistent with our physical optics model, and the data gives excellent measurements of the indices of A-cut sapphire. We have also taken preliminary spectra of the integrated HWP, optical system, and detectors in the prototype Spider receiver. We calculate the variation in response of the HWP between observing the CMB and foreground spectra, and estimate that it should not limit the Spider constraints on inflation

A Review of Studies Evaluating Insecticide Barrier Treatments for Mosquito Control From 1944 to 2018

Background and Purpose: Barrier insecticide treatments have a long history in mosquito control programs but have been used more frequently in the United States in recent years for control of invasive “backyard� species (eg, Aedes albopictus) and increases in incidence of vector-borne diseases (eg, Zika). Methods: We reviewed the published literature for studies investigating barrier treatments for mosquito control during the last 74 years (1944-2018). We searched databases such as PubMed, Web of Science, and Google Scholar to retrieve worldwide literature on barrier treatments. Results: Forty-four studies that evaluated 20 active ingredients (AIs) and 21 formulated products against multiple mosquito species are included. Insecticides investigated for efficacy included organochlorines (dichlorodiphenyltrichloroethane [DDT], β-hexachlorocyclohexane [BHC]), organophosphates (malathion), and pyrethroids (bifenthrin, deltamethrin, permethrin, lambda-cyhalothrin) as AIs. Study design varied with multiple methods used to evaluate effectiveness of barrier treatments. Barrier treatments were effective at lowering mosquito populations although there was variation between studies and for different mosquito species. Factors other than AI, such as exposure to rainfall and application equipment used, also influenced control efficacy. Conclusions: Many of the basic questions on the effectiveness of barrier insecticide applications have been answered, but several important details still must be investigated to improve precision and impact on vector-borne pathogen transmission. Recommendations are made to assist future evaluations of barrier treatments for mosquito control and to limit the potential development of insecticide resistance