Nocturnal camouflage through background matching against moonlight.

Camouflage is often considered a daytime phenomenon based on light and shade. Nocturnal camouflage can also occur, but its mechanistic basis remains unclear. Here, we analyze the conditions for background matching (BM) of avian predators against the night sky.

Digitizing translucent object appearance by validating computed optical properties.

The optical properties available for an object are most often fragmented and insufficient for photorealistic rendering of the object. We propose a procedure for digitizing a translucent object with sufficient information for predictive rendering of its appearance. Based on object material descriptions, we compute optical properties and validate or adjust this object appearance model based on comparison of simulation with spectrophotometric measurements of the bidirectional scattering-surface reflectance distribution function (BSSRDF).

Primary facility for traceable measurement of BSSRDF: erratum.

An erratum is presented to correct the measurement equation used for the calculation of the BSSRDF in our manuscript [Opt. Express29 (21), 34175 (2021)10.1364/OE.

Safety and Efficacy of a MEURI Program for the Use of High Dose Ivermectin in COVID-19 Patients.

Background: In the absence of antiviral alternatives, interventions under research for COVID-19 might be offered following guidelines from WHO for monitored emergency use of unregistered and experimental interventions (MEURI). Ivermectin is among several drugs explored for its role against SARS-CoV-2, with a well-known safety profile but conflicting data regarding clinical utility for COVID-19. The aim of this report is to inform on the results of a MEURI Program of high-dose ivermectin in COVID-19 carried out by the Ministry of Health of the Province of La Pampa, Argentina.

Accurate physics-based digital reproduction of effect coatings.

We built an improved 3D rendering framework to accurately visualize the complete appearance of effect coatings, including metallic effects, sparkle and iridescence. Spectral reflectance measurements and sparkle indexes from a commercially available multi-angle spectrophotometer (BYKmac-i) were used together with physics-based approaches, such as flake-based reflectance models, to implement efficiently the appearance reproduction from a small number of bidirectional measurement geometries. With this rendering framework, we rendered a series of effect coating samples on an iPad display, simulating how these samples would be viewed inside a Byko-spectra effect light booth.

Primary facility for traceable measurement of the BSSRDF.

The bidirectional scattering-surface reflectance distribution function (BSSRDF) is the function that describes the variation of the radiance of the elementary areas of a surface with respect to the directionally incident radiant flux on that surface. Measurements of the BSSRDF are important for characterizing the translucency of objects and for obtaining those optical parameters affecting volume scattering. However, to date, no traceable measurements of this function are available, since, likely due to its technical complexity, no standard measurement procedure has been established.

Visual validation of the appearance of chromatic objects rendered from spectrophotometric measurements.

We validate a physically based and spectral rendering framework with improved color reproduction. With a recently developed model, we take into account both the colorimetric specifications of the rendering display as well as the spectral and angular characteristics of lighting and also the spectral reflectance of the objects. Therefore, it should provide much better color reproduction than those based on the common standard red, green, blue (sRGB) color space.

Goniochromatic assessment of gray scales for color change.

The dependence of color differences on the illumination and viewing directions for two widely used gray scales for color change (SDCE and AATCC) was evaluated through measuring the spectral bidirectional reflectance distribution function (BRDF) by a gonio-spectrophotometer of metrological quality. Large incidence and viewing angles must be specially avoided using these gray scales because, in these conditions, color differences vary considerably from those established in ISO 105-A02 and ASTM D2616-12. While the visual appearance of the SDCE and AATCC gray scales for color change is similar, our results indicate that their goniochromatic properties are different.

Measuring the Human Ultra-Weak Photon Emission Distribution Using an Electron-Multiplying, Charge-Coupled Device as a Sensor.

Ultra-weak photon emission (UPE) is the spontaneous emission from living systems mainly attributed to oxidation reactions, in which reactive oxygen species (ROS) may play a major role. Given the capability of the next-generation electron-multiplying CCD (EMCCD) sensors and the easy use of liquid crystal tunable filters (LCTF), the aim of this work was to explore the potential of a simple UPE spectrometer to measure the UPE from a human hand. Thus, an easy setup was configured based on a dark box for inserting the subject's hand prior to LCTF as a monochromator and an EMCCD sensor working in the full vertical binning mode (FVB) as a spectra detector.

Short-term effects of a green coffee extract-, Garcinia c ambogia- and L-carnitine-containing chewing gum on snack intake and appetite regulation.

Introduction: Different studies have assessed the influence of chewing gum to aid control of appetite and reduce food intake.

Purpose: The aims of the present study were to evaluate the effects of chewing gum on satiety, food hedonics and snack intake and to explore the potential effects of the combination of Garcinia c ambogia, green coffee extract and L-carnitine on satiety, when administered in a gum format.

Methods: This was a prospective study in which 57 subjects randomly received three kinds of treatments, in a crossover design: (1) active gum; (2) placebo gum; and (3) no gum.

[Research in Psychopharmacology].

Research in psychopharmacology began around 1950 with the description of antipsychotic effect of chlorpromazine followed shortly later with the mechanism of action of antidepressants. In these initial phases, pharmacy industry was open to knowledge and made efforts tending to the development to new drugs that showed efficacy and good safety profiles. In parallel development of theories attempting to find the etiology of psychiatric disorders acquired impulse.

Visibility of sparkle in metallic paints.

For suitable illumination and observation conditions, sparkles may be observed in metallic coatings. The visibility of these sparkles depends critically on their intensity, and on the paint medium surrounding the metallic flakes. Based on previous perception studies from other disciplines, we derive equations for the threshold for sparkles to be visible.

Characterizing integration time and gray-level-related nonlinearities in a NMOS sensor.

We report a nonlinearity effect related to the integration time in a double-beam spectroradiometer equipped with two negative-module metal-oxide semiconductor (NMOS) sensors. This effect can be explained by the addition of photoelectrons produced by the radiant flux on the sensors during the readout phase to the photoelectrons produced during the measurement phase. A new method is proposed to characterize and correct both gray-level and integration-time-related nonlinearities in NMOS sensors.

Isochromatic lines as extension of Helmholtz reciprocity principle for effect paints.

Flake-based parameters were recently introduced as a physical concept to predict a series of measurement geometries producing similar reflection data for effect paints. We derive expressions to calculate these so-called isochromatic lines, connecting the two Helmholtz-reciprocal in-plane geometries with a series of out-of-plane geometries. Thus isochromatic lines can be regarded as an extension of the Helmholtz reciprocity principle, which is valid for effect paints.

Evaluation of the satiating properties of a nutraceutical product containing Garcinia cambogia and Ascophyllum nodosum extracts in healthy volunteers.

A nutraceutical product composed of a combination of Garcinia cambogia, l-carnitine and a seaweed extract of Ascophyllum nodosum has been recently developed. The aim of the present study was to characterize its effects on subjective satiety sensations and food preferences in healthy volunteers. In a crossover design, 28 subjects (21 females and 7 males, aged 31 ± 5, BMI 22.

Spectral BRDF-based determination of proper measurement geometries to characterize color shift of special effect coatings.

A reduced set of measurement geometries allows the spectral reflectance of special effect coatings to be predicted for any other geometry. A physical model based on flake-related parameters has been used to determine nonredundant measurement geometries for the complete description of the spectral bidirectional reflectance distribution function (BRDF). The analysis of experimental spectral BRDF was carried out by means of principal component analysis.

Spectral and geometrical variation of the bidirectional reflectance distribution function of diffuse reflectance standards.

A study on the variation of the spectral bidirectional reflectance distribution function (BRDF) of four diffuse reflectance standards (matte ceramic, BaSO(4), Spectralon, and white Russian opal glass) is accomplished through this work. Spectral BRDF measurements were carried out and, using principal components analysis, its spectral and geometrical variation respect to a reference geometry was assessed from the experimental data. Several descriptors were defined in order to compare the spectral BRDF variation of the four materials.

Variables separation of the spectral BRDF for better understanding color variation in special effect pigment coatings.

A type of representation of the spectral bidirectional reflectance distribution function (BRDF) is proposed that distinctly separates the spectral variable (wavelength) from the geometrical variables (spherical coordinates of the irradiation and viewing directions). Principal components analysis (PCA) is used in order to decompose the spectral BRDF in decorrelated spectral components, and the weight that they have at every geometrical configuration of irradiation/viewing is established. This method was applied to the spectral BRDF measurement of a special effect pigment sample, and four principal components with relevant variance were identified.

Maintenance treatment with fluoxetine is necessary to sustain normal levels of synaptic markers in an experimental model of depression: correlation with behavioral response.

Dysfunction of hippocampal plasticity has been proposed to play a critical role in the pathophysiology of depression. However, antidepressant drug effects on synaptic plasticity and cytoskeletal remodeling remain controversial. The aim of the present study was to evaluate in animals exposed to the learned helplessness (LH) paradigm, an accepted experimental model of depression, the effect of chronic treatment with fluoxetine (FLX) on synaptic and cytoskeletal proteins known to undergo plastic changes.

Cytoskeleton of hippocampal neurons as a target for valproic acid in an experimental model of depression.

Background: Atrophy of pyramidal hippocampal neurons and of the entire hippocampus has been reported in experimental models of depression and in depressive patients respectively. We investigated the efficacy of valproic acid (VPA) for reversing a depressive-like behaviour and a cytoskeletal alteration in the hippocampus, the loss of the light neurofilament subunit (NF-L).

Methods: Depressive-like behaviour was induced by inescapable stress.

Chronic treatment with high doses of corticosterone decreases cytoskeletal proteins in the rat hippocampus.

Hypercortisolism is a common trait of Cushing's disease and depression. These two disorders also share hippocampal volume decrease and cognitive deficits. However, experimentally induced hypercortisolism induces neuronal atrophy, which has been proposed to be the phenomenon underlying the hippocampal shrinkage.

Principal components analysis of the photoresponse nonuniformity of a matrix detector.

The principal component analysis is used to identify and quantify spatial distributions of relative photoresponse as a function of the exposure time for a visible CCD array. The analysis shows a simple way to define an invariant photoresponse nonuniformity and compare it with the definition of this invariant pattern as the one obtained for long exposure times. Experimental data of radiant exposure from levels of irradiance obtained in a stable and well-controlled environment are used.

[Stability of medicine: its relationship with their expiration date and with degradation products].

The expiration date of medicines is an application and direct interpretation of the knowledge obtained from stability studies, which are conducted under rigorous conditions, employing appropriate statistical and conceptual procedures. Instability of an active compound may result on one hand in efficacy decrease and on other in the possible presence of toxic degradation products. In this review, we analyze the reasons underlying the definition of the expiration date of medicines and their relationship with the stability, we mention the essays that must be performed to support this definition and finally give examples of degradation products and of their possible adverse effects.

[The relationship between the Wnt signaling and the psychiatric diseases].

It has been demonstrated that the neuronal plasticity and resilience could participate in the pathophysiology of neurodegenerative diseases such as Alzheimer and others like depression and schizophrenia. Recently, it has been proposed a new intracellular pathway, known as Wnt pathway, which could be related to the induction of the plastic changes mentioned above. The glycogen synthase kinase-3beta (GSK-3beta), one of the main enzymes of the Wnt signaling, has been associated to Alzheimer;s and schizophrenia diseases etiology.

Apparent violation of the radiant exposure reciprocity law in interline CCDs.

We analyze in detail the apparent violation of the reciprocity law that occurs for an interline CCD array owing to its responsivity that varies with exposure time, and we investigate other parameters having an influence on this variation, such as the numerical aperture of the system or the illumination wavelength. The variation can be explained from a qualitative point of view by the charge leakage that occurs from the sense region to the register region during readout time. This change of the responsivity can be avoided either by using a synchronized external shutter or by limiting the numerical aperture while keeping relatively high exposure times.