Effect of the order and disorder of BaMoO4 powders in photoluminescent properties

The study of the photoluminescent properties affected by order and disorder of the BaMoO4 powders is the principal objective in this work. BaMoO4 compounds were prepared using soft chemical process called Complex Polymerization Method. In this work, different deagglomeration types and different heating rates were used to promote different disorder degrees. Scheelite type phase (BaMoO4) was determined by X-ray Diffraction (XRD), Fourier Transformed Infra-Red (FTIR) and Raman spectroscopy after heat treating the sample at 400 degrees C. The room temperature luminescence spectra revealed an intense single-emission band in the visible region. Based on XRD and Raman data it was observed that the transition between the completely disordered structure to completely ordered structure is a good condition for photoluminescence (PL) emission. The best PL emission is obtained when the material possesses short range disorder, i.e., is periodically ordered (XRD), but some disorder as measured by Raman spectroscopy. The excellent optical properties observed for disordered BaMoO4 suggested that this material is a highly promising candidate for optical applications.

Influence of the temperature on the nucleation of silver nanoparticles in Tm3+/Yb3+ codoped PbO-GeO2 glasses

The influence of the temperature on the nucleation of silver nanoparticles (NPs) in Tm3+/Yb3+ codoped PbO-GeO2 glasses was studied in this work. The infrared-to-visible frequency upconversion (UC) luminescence of Tm3+ ions was used to probe the NPs nucleation and the results were correlated with the increase of the heat-treatment temperature. Emission spectra in the blue-red region were measured by exciting the samples with a cw 980 nm diode laser in resonance with the Yb3+ transition (F-2(7/2) -> F-2(5/2)). The results were correlated with transmission electron microscopy measurements and revealed the different behavior of the nucleation process as a function of temperature.The enhanced UC emission in the visible region is attributed to the increased local field in the proximity of the silver NPs combined with the Yb3+ -> Tm3+ energy transfer. (C) 2010 Elsevier B.V. All rights reserved.

First principles calculations on the origin of violet-blue and green light photoluminescence emission in SrZrO3 and SrTiO3 perovskites

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

Atmospheric cosmic rays in the South Atlantic anomaly region

To study the production and propagation of fast secondaries particles in the atmosphere, data collected during eleven quiet-time balloon flights are analysed. Comparisons of these data with those obtained in different geomagnetic rigidity regions permit to estimate the contributions of the proton and electron components in the measured intensities. Derivations of this last component in the «upward» and «downward» moving electrons fluxes indicate that in the anomaly region a fraction of these particles, produced by the primary protons, are leaving the atmosphere and will not return to the Earth. © 1991 Società Italiana di Fisica.

Spectroscopic characteristics of Er3+ in the two crystallographic sites of Gd2SiO5

Gd2SiO5 is among the interesting and suitable hosts for Er3+ which find extensive applications in the infrared, visible and ultraviolet spectral regions. In order to investigate its potentialities, a prior study of the spectroscopic behaviour of Er3+ substituting for Gd3+ ions in the two crystallographic sites of the host was performed. Absorption, excitation, site-selective emission and time-resolved spectroscopies were employed in the visible spectral region to study transitions between excited 4S3/2 and ground 4I15/2 states. These levels multiplets were attributed to each site separately, and their corresponding 4S3/2 lifetimes (1.8 ± 0.1 μs for site 1 and 3.2 ± 0.1 μs for site 2) were determined.

Frequency of the HFE C282Y and H63D polymorphisms in Brazilian malaria patients and blood donors from the Amazon region

Malaria is an endemic parasitosis and its causitive agent, Plasmodium, has a metabolism linked to iron supply. HFE is a gene with the polymorphisms C282Y and H63D, which are associated with a progressive iron accumulation in the organism leading to a disease called hereditary hemochromatosis. The aim of the present study was to determine the allelic and genotypic frequencies of the HFE gene polymorphisms in malaria patients and blood donors from the Brazilian Amazon region. We screened 400 blood donors and 400 malaria patients for the HFE C282Y and H63D polymorphisms from four states of the Brazilian Amazon region by polymerase chain reaction and restriction fragment length polymorphism analysis. We did not find any C282Y homozygous individuals, and the only five heterozygous individuals detected were from Pará State. The most frequent genotype in the North region of Brazil was the H63D heterozygote, in both study groups. Our results contribute to the concept that the Brazilian Amazon region should not be regarded as a single entity in South America. These polymorphisms did not influence the symptoms of malaria in the population studied, as neither severe signs nor high parasitemia were observed. Therefore, different hereditary hemochromatosis diagnostic and control measures must be developed and applied within its diverse locations. Investigations are currently being carried out in our laboratory in order to determine the importance of the coexistence of hereditary hemochromatosis in patients affected by parasitic diseases, such as malaria. ©FUNPEC-RP.

Lidar observation campaign of sugar cane fires and industrial emissions in the State of São Paulo, Brazil

Brazil has an important role in the biomass burning, with the detection of approximately 100,000 burning spots in a single year (2007). Most of these spots occur in the southern part of the Amazon basin during the dry season (from August to november) and these emissions reach the southeast of the country, a highly populated region and with serious urban air pollution problems. With the growing demand on biofuels, sugarcane is considerably expanding in the state of São Paulo, being a strong contributor to the bad air quality in this region. In the state of São Paulo, the main land use are pasture and sugarcane crop, that covers around 50% and 10% of the total area, respectively. Despite the aerosol from sugarcane burning having reduced atmospheric residence time, from a few days to some weeks, they might get together with those aerosol which spread over long distances (hundreds to thousands of kilometers). In the period of June through February 2010 a LIDAR observation campaign was carried in the state of São Paulo, Brazil, in order to observe and characterize optically the aerosols from two distinct sources, namely, sugar cane biomass burning and industrial emissions. For this purpose 2 LIDAR systems were available, one mobile and the other placed in a laboratory, both working in the visible (532 nm) and additionally the mobile system had a Raman channel available (607 nm). Also this campaign counted with a SODAR, a meteorological RADAR specially set up to detect aerosol echoes and gas-particle analyzers. To guarantee a good regional coverage 4 distinct sites were available to deploy the instruments, 2 in the near field of biomass burning activities (Rio Claro and Bauru), one for industrial emissions (Cubatão) and others from urban sources (São Paulo). The whole campaign provide the equivalent of 30 days of measurements which allowed us to get aerosol optical properties such as backscattering/extinction coefficients, scatter and LIDAR ratios, those were used to correlate with air quality and meteorological indicators and quantities. In this paper we should focus on the preliminary results of the Raman LIDAR system and its derived aerosol optical quantities. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Signal classification of submerged aquatic vegetation based on the hemispherical-conical reflectance factor spectrum shape in the yellow and red regions

The water column overlying the submerged aquatic vegetation (SAV) canopy presents difficulties when using remote sensing images for mapping such vegetation. Inherent and apparent water optical properties and its optically active components, which are commonly present in natural waters, in addition to the water column height over the canopy, and plant characteristics are some of the factors that affect the signal from SAV mainly due to its strong energy absorption in the near-infrared. By considering these interferences, a hypothesis was developed that the vegetation signal is better conserved and less absorbed by the water column in certain intervals of the visible region of the spectrum; as a consequence, it is possible to distinguish the SAV signal. To distinguish the signal from SAV, two types of classification approaches were selected. Both of these methods consider the hemispherical-conical reflectance factor (HCRF) spectrum shape, although one type was supervised and the other one was not. The first method adopts cluster analysis and uses the parameters of the band (absorption, asymmetry, height and width) obtained by continuum removal as the input of the classification. The spectral angle mapper (SAM) was adopted as the supervised classification approach. Both approaches tested different wavelength intervals in the visible and near-infrared spectra. It was demonstrated that the 585 to 685-nm interval, corresponding to the green, yellow and red wavelength bands, offered the best results in both classification approaches. However, SAM classification showed better results relative to cluster analysis and correctly separated all spectral curves with or without SAV. Based on this research, it can be concluded that it is possible to discriminate areas with and without SAV using remote sensing. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Larval development of Lepidophthalmus siriboia Felder & Rodrigues, 1993 (Decapoda: Thalassinidea) from the Amazon region, reared in the laboratory

O desenvolvimento completo de Lepidophthalmus siriboia Felder & Rodrigues, 1993 foi descrito e ilustrado em detalhes a partir de espécimens cultivados em laboratório. Fêmeas ovígeras foram coletadas na ilha de Canela nordeste do Estado do Pará. As larvas eclodem como prezoea e o desenvolvimento larval consiste de 3 estágios de zoea e 1 de megalopa. O desenvolvimento dos 3 estágios de zoea durou em média de 69 a 111 horas. A duração de megalopa foi cerca de 185 horas (cerca de 8 dias). O primeiro juvenil foi alcançado em 254 horas (cerca de 10 dias) após a eclosão. Comparações morfológicas com espécies do mesmo gênero são discutidas.

Frequency of antibodies to Babesia bigemina, B. bovis, Anaplasma marginale, Trypanosoma vivax and Borrelia burdgorferi in cattle from the northeastern region of the state of Pará, Brazil

A babesiose, a anaplasmose e a tripanossomose são enfermidades relevantes, potencialmente causadoras de morbidade em bovinos, levando a perdas econômicas. A borreliose assume importância como zoonose potencial. O objetivo desse estudo foi determinar, por meio do ensaio de imunoadsorção enzimática (ELISA), a freqüência de anticorpos para Babesia bigemina, B. bovis, Anaplasma marginale, Trypanosoma vivax e Borrelia burgdorferi em bovinos da região nordeste do Estado do Pará, Brasil. Amostras de soro de 246 vacas dos municípios de Castanhal e São Miguel do Guamá foram usadas. ELISAs com antígeno bruto foram utilizados para detector anticorpos contra todos os agentes, exceto para A. marginale, para o qual um ELISA indireto com proteína principal de superfície 1a (MSP1a) foi usado. As freqüências de bovinos soropositivos foram: B. bigemina - 99,2%; B. bovis - 98,8%; A. marginale - 68,3%; T. vivax - 93,1% and B. burgdorferi -54,9% As freqüências de bovinos soropositivos para B. bovis e B. bigemina sugerem uma alta taxa de transmissão desses organismos por carrapatos, na região estudada, a qual pode ser classificada com sendo de estabilidade enzoótica para os hemoparasitos. A baixa freqüência de bovinos soropositivos para A. marginale pode ser atribuída a uma menor sensibilidade do ELISA com antígeno recombinante, ou uma menor taxa de inoculação da riquétsia pelos carrapatos, quando comparada àquelas observadas para Babesia sp. A alta freqüência de bovinos soropositivos para T. vivax indica que esse hemoprotozoário é prevalente em rebanhos do nordeste do Estado do Pará. O percentual de animais com anticorpos homólogos para B. burgdorferi indica a presenças deste espiroquetídeo transmitido por carrapatos na população de bovinos da região estudada.

Constitutive heterochromatin and nucleolus organizer region in the knifefish, Apteronotus albifrons (Pisces, Apteronotidae)

The C-banding and silver staining of the chromosomes of the knifefish Apteronotus albifrons (2n=24), demonstrated the presence of constitutive heterochromatin in the centromeric region of every chromosome, except pair 4, where the entire long arm was darkly stained, the silver stain positive nucleolus organizer region (NOR) being embedded in it. © 1981 Birkhüuser Verlag.

Unpredictable chronic mild stress exerts anxiogenic-like effects and activates neurons in the dorsal and caudal region and in the lateral wings of the dorsal raphe nucleus

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

Is the meander growth in the Brazil Current system off Southeast Brazil due to baroclinic instability?

Temporally-growing frontal meandering and occasional eddy-shedding is observed in the Brazil Current (BC) as it flows adjacent to the Brazilian Coast. No study of the dynamics of this phenomenon has been conducted to date in the region between 22 degrees S and 25 degrees S. Within this latitude range, the flow over the intermediate continental slope is marked by a current inversion at a depth that is associated with the Intermediate Western Boundary Current (IWBC). A time series analysis of 10-current-meter mooring data was used to describe a mean vertical profile for the BC-IWBC jet and a typical meander vertical structure. The latter was obtained by an empirical orthogonal function (EOF) analysis that showed a single mode explaining 82% of the total variance. This mode structure decayed sharply with depth, revealing that the meandering is much more vigorous within the BC domain than it is in the IWBC region. As the spectral analysis of the mode amplitude time series revealed no significant periods, we searched for dominant wavelengths. This search was done via a spatial EOF analysis on 51 thermal front patterns derived from digitized AVHRR images. Four modes were statistically significant at the 95% confidence level. Modes 3 and 4, which together explained 18% of the total variance, are associated with 266 and 338-km vorticity waves, respectively. With this new information derived from the data, the [Johns, W.E., 1988. One-dimensional baroclinically unstable waves on the Gulf Stream potential vorticity gradient near Cape Hatteras. Dyn. Atmos. Oceans 11, 323-350] one-dimensional quasi-geostrophic model was applied to the interpolated mean BC-IWBC jet. The results indicated that the BC system is indeed baroclinically unstable and that the wavelengths depicted in the thermal front analysis are associated with the most unstable waves produced by the model. Growth rates were about 0.06 (0.05) days(-1) for the 266-km (338-km) wave. Moreover, phase speeds for these waves were low compared to the surface BC velocity and may account for remarks in the literature about growing standing or stationary meanders off southeast Brazil. The theoretical vertical structure modes associated with these waves resembled very closely to the one obtained for the current-meter mooring EOF analysis. We interpret this agreement as a confirmation that baroclinic instability is an important mechanism in meander growth in the BC system. (C) 2008 Elsevier B.V. All rights reserved.

Trans-Planckian problem in the healthy extension of Horava-Lifshitz gravity

Planck scale physics may influence the evolution of cosmological fluctuations in the early stages of cosmological evolution. Because of the quasiexponential redshifting, which occurs during an inflationary period, the physical wavelengths of comoving scales that correspond to the present large-scale structure of the Universe were smaller than the Planck length in the early stages of the inflationary period. This trans-Planckian effect was studied before using toy models. The Horava-Lifshitz (HL) theory offers the chance to study this problem in a candidate UV complete theory of gravity. In this paper we study the evolution of cosmological perturbations according to HL gravity assuming that matter gives rise to an inflationary background. As is usually done in inflationary cosmology, we assume that the fluctuations originate in their minimum energy state. In the trans-Planckian region the fluctuations obey a nonlinear dispersion relation of Corley-Jacobson type. In the "healthy extension" of HL gravity there is an extra degree of freedom which plays an important role in the UV region but decouples in the IR, and which influences the cosmological perturbations. We find that in spite of these important changes compared to the usual description, the overall scale invariance of the power spectrum of cosmological perturbations is recovered. However, we obtain oscillations in the spectrum as a function of wave number with a relative amplitude of order unity and with an effective frequency which scales nonlinearly with wave number. Taking the usual inflationary parameters we find that the frequency of the oscillations is so large as to render the effect difficult to observe.

Mycobacterium bovis infection in goats from the Northeast Region of Brazil

A total of 8,058 male and female mixed-breed goats and 1-4 years of age were slaughtered over a period of 7 months at the public slaughterhouse of Patos city, Paraíba state, in the Northeast region of Brazil; 822 animals were inspected for gross lesions of tuberculosis, and 12 (1.46%) had lesions suggestive of tuberculosis in the mammary gland, lungs, liver and mediastinal, mesenteric, submandibular, parotid and prescapular lymph nodes. Presence of granulomatous lesions was confirmed in the submandibular lymph node of one (8.3%) goat at the histopathological examination and at the mycobacterium culture the same sample was confirmed positive. Isolate was confirmed as belonging to the M. tuberculosis complex by PCR restriction enzyme analysis (PRA). Spoligotyping identified the isolate into spoligotype SB0295 on the M. bovis Spoligotype Database website (www.mbovis.org), and it was classified as M. bovis. The occurrence of M. bovis in goats in this study suggests that this species may be a potential source of infection for humans and should be regarded as a possible problem in the advancement of control and eradication program for bovine tuberculosis in Brazil.