Caracterização de superfícies de vidros expostas a vapores de KNO3

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação de parâmetros ópticos de materiais por análise de Kramers-Kronig de espectros de infravermelho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The triple near-Earth asteroid (153591) 2001 SN263: an ultra-blue, primitive target for the Aster space mission

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variable assessment of wing colouration in aerial contests of the red-winged damselfly Mnesarete pudica (Zygoptera, Calopterygidae)

Wing pigmentation is a trait that predicts the outcome of male contests in some damselflies. Thus, it is reasonable to suppose that males would have the ability to assess wing pigmentation and adjust investment in a fight according to the costs that the rival may potentially impose. Males of the damselfly Mnesarete pudica exhibit red-coloured wings and complex courtship behaviour and engage in striking male– male fights. In this study, we investigated male assessment behaviour during aerial contests. Theory suggests that the relationship between male resource-holding potential (RHP) and contest duration describes the kind of assessment adopted by males: self-assessment, opponent-only assessment or mutual assessment. A recent theory also suggests that weak and strong males exhibit variations in the assessment strategies adopted. We estimated male RHP through male body size and wing colouration (i.e. pigmentation, wing reflectance spectra and transmission spectra) and studied the relationship between male RHP and contest duration from videodocumented behavioural observations of naturally occurring individual contests in the field. The results showed that males with more opaque wings and larger red spots were more likely to win contests. The relationships between RHP and contest durations partly supported the self-assessment and the mutual assessment models. We then experimentally augmented the pigmented area of the wings, in order to evaluate whether strong and weak males assess rivals’ RHP through wing pigmentation. Our experimental manipulation, however, clearly demonstrated that strong males assess rivals’ wing pigmentation. We finally suggest that there is a variation in the assessment strategy adopted by males

Variable assessment of wing colouration in aerial contests of the red-winged damselfly Mnesarete pudica (Zygoptera, Calopterygidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rietveld refinement, cluster modelling, growth mechanism and photoluminescence properties of CaWO4: Eu3+ microcrystals

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High quality colloidal crystals with different architectures and their optical properties

In this present work high quality PMMA opals with different sphere sizes, silica opals from large size spheres, multilayer opals, and inverse opals were fabricated. Highly monodisperse PMMA spheres were synthesized by surfactant-free emulsion polymerization (polydispersity ~2%). Large-area and well-ordered PMMA crystalline films with a homogenous thickness were produced by the vertical deposition method using a drawing device. Optical experiments have confirmed the high quality of these PMMA photonic crystals, e.g., well resolved high-energy bands of the transmission and reflectance spectra of the opaline films were observed. For fabrication of high quality opaline photonic crystals from large silica spheres (diameter of 890 nm), self-assembled in patterned Si-substrates a novel technique has been developed, in which the crystallization was performed by using a drawing apparatus in combination with stirring. The achievements comprise a spatial selectivity of opal crystallization without special treatment of the wafer surface, the opal lattice was found to match the pattern precisely in width as well as depth, particularly an absence of cracks within the size of the trenches, and finally a good three-dimensional order of the opal lattice even in trenches with a complex confined geometry. Multilayer opals from opaline films with different sphere sizes or different materials were produced by sequential crystallization procedure. Studies of the transmission in triple-layer hetero-opal revealed that its optical properties cannot only be considered as the linear superposition of two independent photonic bandgaps. The remarkable interface effect is the narrowing of the transmission minima. Large-area, high-quality, and robust photonic opal replicas from silicate-based inorganic-organic hybrid polymers (ORMOCER® s) were prepared by using the template-directed method, in which a high quality PMMA opal template was infiltrated with a neat inorganic-organic ORMOCER® oligomer, which can be photopolymerized within the opaline voids leading to a fully-developed replica structure with a filling factor of nearly 100%. This opal replica is structurally homogeneous, thermally and mechanically stable and the large scale (cm2 size) replica films can be handled easily as free films with a pair of tweezers.

Eggshell colour is more strongly affected by maternal identity than by dietary antioxidants in a captive poultry system

1.Biologists have long puzzled over the apparent conspicuousness of blue-green eggshell coloration in birds. One candidate explanation is the sexual signalling hypothesis that the blue-green colour of eggshells can reveal an intrinsic aspect of females' physiological quality, with only high-quality females having sufficient antioxidant capacity to pigment their eggs with large amounts of biliverdin. Subsequent work has argued instead that eggshell colour might signal condition-dependent traits based on diet. 2.Using Araucana chickens that lay blue-green eggs, we explored (i) whether high levels of dietary antioxidants yield eggshells with greater blue-green reflectance, (ii) whether females differ from one another in eggshell coloration despite standardized environments, diets and rearing conditions, and (iii) the relative strength with which diet vs. female identity affects eggshell coloration. 3.We reared birds to maturity and then placed them on either a high- or low-antioxidant diet, differing fourfold in Vitamin E acetate and Vitamin A retinol. After 8 weeks, the treatments were reversed, such that females laid eggs on both diets in an order-balanced design. We measured the reflectance spectra of 545 eggs from 25 females. 4.Diet had a very limited effect on eggshell spectral reflectance, but individual females differed strongly and consistently from one another, despite having been reared under uniform conditions. However, predictions from avian visual modelling suggest that most of the egg colour differences between females, and nearly all of the differences between diets, are unlikely to be visually discriminable. 5.Our data suggest that eggshell reflectance spectra may carry information on intrinsic properties of the female that laid the eggs, but the utility of this coloration as a signal to conspecifics in this species may be limited by the sensitivity of a receiver to detect it.

(Table 1) Color, Fe-C-S chemistry and carbonate content from ODP Sites 172-1062 and 172-1063

Reflectance spectra collected during ODP Leg 172 were used in concert with solid phase iron chemistry, carbonate content, and organic carbon content measurements to evaluate the agents responsible for setting the color in sediments. Factor analysis has proved a valuable and rapid technique to detect the local and regional primary factors that influence sediment color. On the western North Atlantic drifts, sediment color is the result of primary mineralogy as well as diagenetic changes. Sediment lightness is controlled by the carbonate content while the hue is primarily due to the presence of hematite and Fe2+/Fe3+ changes in clay minerals. Hematite, most likely derived from the Permo-Carboniferous red beds of the Canadian Maritimes, is differentially preserved at various sites due to differences in reductive diagenesis and dilution by other sedimentary components. Various intensities for diagenesis result from changes in organic carbon content, sedimentation rates, and H2S production via anaerobic methane oxidation. Iron monosulfides occur extensively at all high sedimentation sites especially in glacial periods suggesting increased high terrigenous flux and/or increased reactive iron flux in glacials.

(Table T1) Calcium carbonate content of sediments from ODP Leg 172 sites

Visual-domain diffuse reflectance data collected aboard the JOIDES Resolution with the Minolta spectrometer CM-2002 during Ocean Drilling Program Leg 172 have been used to estimate successfully the carbonate content of sediments. Calibration equations were developed for each site and for each lithostratigraphic unit (or subunit at Site 1063) using multiple linear regression on raw as well as pretreated reflectance spectra (i.e., first-order derivation and squaring of raw reflectance spectra) for a total of 4141 direct carbonate measurements. The root-mean-square errors of 4% to 7% are within the range of previous estimates using diffuse reflectance data and are acceptable for the general extensive range of carbonate contents (i.e., 0-70 wt%) that characterize sedimentation at Leg 172 sites.

(Table 2) Weight percent organic carbon from ODP Site 138-847

As the length of marine cores increases and sampling intervals decrease, the need for rapid and inexpensive means of determining sediment composition has become apparent. In this study we examine one potentially useful technique for assessing compositional changes in marine cores, diffuse reflectance spectrophotometry. We examined near-ultraviolet, visible, and near-infrared reflectance spectra from five data sets. Each data set consists of calibration samples and test samples. The calibration samples' spectra were related to a sediment component using multiple linear regression. The resulting regression or calibration equations were then evaluated using the test samples. Calibration equations were written relating spectra to several sediment components incduding carbonate (Atlantic and east Pacific Rise ODP Site 847), organic carbon content (Atlantic and east Pacific Rise), and opal content (east Pacific Rise). The correlation coefficients for the regression equations ranged from a high of 0.99 for carbonate and opal at ODP Site 847 to a low of 0.97 for Atlantic carbonate indicating that spectral variations are highly correlated to sediment composition. All of the equations include a substantial number of variables from shorter visible and longer near ultraviolet wavelengths suggesting that these wavelengths are especially important for devices designed specifically to scan marine cores. Although equations for estimating organic and carbonate content appear independent of other sediment components, the opal equation is strongly dependent on carbonate content indicating that opal concentration is correlated to carbonate content. Tests of the calibration equations indicated that all our equations reasonably estimate the pattern of changes, either down core or in surface sediments. Where our spectral estimates have difficulty is with absolute values, frequently over or underestimating observed values by a substantial amount. Within these limitations diffuse reflectance spectrophotometry can be a useful tool for characterizing marine cores and as our understanding of the relationship between spectra and mineralogy improves so will estimates of absolute values.

(Table T1) Mineralogy of ODP Leg 199 and DSDP Hole 16-162 sediments - comparison of methods

During Ocean Drilling Program Leg 199 in the equatorial Pacific, visible and near-infrared spectroscopy (VNIS) was used to measure the reflectance spectra (350-2500 nm) of 1343 sediment samples. Reflectance spectra were also measured for a suite of 60 samples of known mineralogy, thereby providing a local ground-truth calibration of spectral features to percentages of calcite, opal, smectite, and illite. The associated algorithm was used to calculate mineral percentages from the 1343 spectra. Using multiple regression and VNIS mineralogy, multisensor track physical properties and light spectroscopy data were then converted into continuous high-resolution mineralogy logs.

VIS/NIR spectral signature for the identification of peanut contamination of powder foods

Visible-near infrared reflectance spectra are proposed for the characterization of IRMM 481 peanuts variety in comparison to powder food materials: wheat flour, milk and cocoa. Multidimensional analysis of reflectance spectra of powder samples shows a specific NIR band centred at 1200 nm that identifies peanut compared to the rest of food ingredients, regardless compaction level and temperature. Spectral range of 400-1000 nm is not robust for identification of blanched peanut. The visible range has shown to be reliable for the identification of pre-treatment and processing of unknown commercial peanut samples. A spectral index is proposed based on the combination of three wavelengths around 1200 nm that is 100% robust against pre-treatment (raw or blanched) and roasting (various temperatures and treatment duration).

Analysis of single and binary phases in cerium doped sodium bismuth titanate -Na0.5Bi0.5TiO3 materials

The pure and cerium doped sodium bismuth titanate inorganic powders were synthesized by solid state reaction method. The presence of rhombohedral phase was observed in cerium doped NBT compounds. At 1200 ºC, the 5% of cerium doped NBT compound forms single perovskite phase. The samples of x = 0.10 and 0.15 were heat treated to 1350 ºC, the binary phases with cerium and bismuth oxides were observed. The X-ray diffraction, fourier transform infrared spectroscopy, reflectance spectra, differential thermal analysis and thermo gravimetric analysis were used to analyze the various properties of samples. Moreover, the effects of cerium doping and calcining temperature on NBT samples were investigated. In this work we present our recent results on the synthesis and characterization of Ce doped sodium bismuth titanate materials.

Ultraviolet plumage colors predict mate preferences in starlings

Avian plumage has long been used to test theories of sexual selection, with humans assessing the colors. However, many birds see in the ultraviolet (<400 nm), to which humans are blind. Consequently, it is important to know whether natural variation in UV reflectance from plumage functions in sexual signaling. We show that female starlings rank males differently when UV wavelengths are present or absent. Principal component analysis of ≈1300 reflectance spectra (300–700 nm) taken from sexually dimorphic plumage regions of males predicted preference under the UV+ treatment. Under UV− conditions, females ranked males in a different and nonrandom order, but plumage reflectance in the human visible spectrum did not predict choice. Natural variation in UV reflectance is thus important in avian mate assessment, and the prevailing light environment can have profound effects on observed mating preferences.