Spatial and temporal variability of the concentration field from localized releases in a regular building array

Spatial and temporal fluctuations in the concentration field from an ensemble of continuous point-source releases in a regular building array are analyzed from data generated by direct numerical simulations. The release is of a passive scalar under conditions of neutral stability. Results are related to the underlying flow structure by contrasting data for an imposed wind direction of 0 deg and 45 deg relative to the buildings. Furthermore, the effects of distance from the source and vicinity to the plume centreline on the spatial and temporal variability are documented. The general picture that emerges is that this particular geometry splits the flow domain into segments (e.g. ���streets��� and ���intersections���) in each of which the air is, to a first approximation, well mixed. Notable exceptions to this general rule include regions close to the source, near the plume edge, and in unobstructed channels when the flow is aligned. In the oblique (45 deg) case the strongly three-dimensional nature of the flow enhances mixing of a scalar within the canopy leading to reduced temporal and spatial concentration fluctuations within the plume core. These fluctuations are in general larger for the parallel flow (0 deg) case, especially so in the long unobstructed channels. Due to the more complex flow structure in the canyon-type streets behind buildings, fluctuations are lower than in the open channels, though still substantially larger than for oblique flow. These results are relevant to the formulation of simple models for dispersion in urban areas and to the quantification of the uncertainties in their predictions.

Towards the main sequence: detailed analysis of weak line and post-T Tauri stars

A detailed study was performed for a sample of low-mass pre-main-sequence (PMS) stars, previously identified as weak-line T Tauri stars, which are compared to members of the Tucanae and Horologium Associations. Aiming to verify if there is any pattern of abundances when comparing the young stars at different phases, we selected objects in the range from 1 to 100 Myr, which covers most of PMS evolution. High-resolution optical spectra were acquired at European Southern Observatory and Observatorio do Pico dos Dias. The stellar fundamental parameters effective temperature and gravity were calculated by excitation and ionization equilibria of iron absorption lines. Chemical abundances were obtained via equivalent width calculations and spectral synthesis for 44 per cent of the sample, which shows metallicities within 0.5 dex solar. A classification was developed based on equivalent width of Li I 6708 angstrom and Ha lines and spectral types of the studied stars. This classification allowed a separation of the sample into categories that correspond to different evolutive stages in the PMS. The position of these stars in the Hertzsprung-Russell diagram was also inspected in order to estimate their ages and masses. Among the studied objects, it was verified that our sample actually contains seven weak-line T Tauri stars, three are Classical T Tauri, 12 are Fe/Ge PMS stars and 21 are post-T Tauri or young main-sequence stars. An estimation of circumstellar luminosity was obtained using a disc model to reproduce the observed spectral energy distribution. Most of the stars show low levels of circumstellar emission, corresponding to less than 30 per cent of the total emission.

VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way

We describe the public ESO near-IR variability survey (VVV) scanning the Milky Way bulge and an adjacent section of the mid-plane where star formation activity is high. The survey will take 1929 h of observations with the 4-m VISTA telescope during 5 years (2010-2014), covering similar to 10(9) point sources across an area of 520 deg(2), including 33 known globular clusters and similar to 350 open clusters. The final product will be a deep near-IR atlas in five passbands (0.9-2.5 mu m) and a catalogue of more than 106 variable point sources. Unlike single-epoch surveys that, in most cases, only produce 2-D maps, the VVV variable star survey will enable the construction of a 3-D map of the surveyed region using well-understood distance indicators such as RR Lyrae stars, and Cepheids. It will yield important information on the ages of the populations. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, INTEGRAL, WISE, Fermi LAT, XMM-Newton, GAIA and ALMA for a complete understanding of the variable sources in the inner Milky Way. This public survey will provide data available to the whole community and therefore will enable further studies of the history of the Milky Way, its globular cluster evolution, and the population census of the Galactic Bulge and center, as well as the investigations of the star forming regions in the disk. The combined variable star catalogues will have important implications for theoretical investigations of pulsation properties of stars. (C) 2009 Elsevier B.V. All rights reserved.

Conflicting structural and geochronological data from the Ibituruna quartz-syenite (SE Brazil): Effect of protracted ""hot"" orogeny and slow cooling rate?

The Ibituruna quartz-syenite was emplaced as a sill in the Ribeira-Aracuai Neoproterozoic belt (Southeastern Brazil) during the last stages of the Gondwana supercontinent amalgamation. We have measured the Anisotropy of Magnetic Susceptibility (AMS) in samples from the Ibituruna sill to unravel its magnetic fabric that is regarded as a proxy for its magmatic fabric. A large magnetic anisotropy, dominantly due to magnetite, and a consistent magnetic fabric have been determined over the entire Ibituruna massif. The magmatic foliation and lineation are strikingly parallel to the solid-state mylonitic foliation and lineation measured in the country-rock. Altogether, these observations suggest that the Ibituruna sill was emplaced during the high temperature (similar to 750 degrees C) regional deformation and was deformed before full solidification coherently with its country-rock. Unexpectedly, geochronological data suggest a rather different conclusion. LA-ICP-MS and SHRIMP ages of zircons from the Ibituruna quartz-syenite are in the range 530-535 Ma and LA-ICP-MS ages of zircons and monazites from synkinematic leucocratic veins in the country-rocks suggest a crystallization at similar to 570-580 Ma, i.e., an HT deformation >35My older than the emplacement of the Ibituruna quartz-syenite. Conclusions from the structural and the geochronological studies are therefore conflicting. A possible explanation arises from (40)Ar-(39)Ar thermochronology. We have dated amphiboles from the quartz-syenite, and amphiboles and biotites from the country-rock. Together with the ages of monazites and zircons in the country-rock, (40)Ar-(39)Ar mineral ages suggest a very low cooling rate: <3 degrees C/My between 570 and similar to 500 Ma and similar to 5 degrees C/My between 500 and 460 Ma. Assuming a protracted regional deformation consistent over tens of My, under such stable thermal conditions the fabric and microstructure of deformed rocks may remain almost unchanged even if they underwent and recorded strain pulses separated by long periods of time. This may be a characteristic of slow cooling ""hot orogens"" that rocks deformed at significantly different periods during the orogeny, but under roughly unchanged temperature conditions, may display almost indiscernible microstructure and fabric. (C) 2009 Elsevier B.V. All rights reserved.

Salmoninae Commensal Bacteria Show a Positive Correlation Between Antibiotic Resistance and Mercury Resistance Profiles

Bacterial isolates from natural sites with high toxic and heavy metal contamination more frequently contain determinants for resistance to antimicrobials. Natural strains were isolated from the ingesta and external slime of Salmo salar (Linnaeus, 1758) and Salvelinusjontinalis (Mitchell, 1814). Fish specimens were acquired from Casco Bay hatcheries, Casco, ME where there is no history of antibiotic use. Seventy-nine bacterial strains, including many well-documented salmonid commensals (an association from which the fish derives no benefit), were identified using 165 rRNA gene sequencing. Mercury resistant isolates were selected for initially on 25��M HgCI2. Strains were then grown at 20-24��C on Trypticase Soy Agar (TSA) plates containing 0-1000��M HgCl2 or 0-130��M Phenyl Mercuric Acetate (PMA). Mercury in the hatchery feed water due to ubiquitous non-point source deposition has selected for the mercury resistance observed in bacterial strains. Antibiotic resistance determinations, as measured by Minimum Inhibitory Concentration MIC) assays were performed on the 79 bacterial isolates using Sensititrel antimicrobial susceptibility panels. A positive linear correlation between the mercury (pMA and HgCl2) MIC's and antibiotic resistance for all observed strains was demonstrated. Conjugation experiments with Pseudomonas, Aeromonas, and Azomonas donors confirmed phenotypic transfer of penicillin and cephem resistances to Escherichia coli DH5a recipients. Conjugation experiments with Pseudomonas donors showed minimal transfer of tetracycline and minoglycoside resistances to Escherichia coli DH5a recipients. Our study suggests that the accumulation of antimicrobial resistances observed in these natural bacterial populations may be due to the indirect selective pressure exerted by environmental mercury.

Ecologia do fitopl��ncton impactado por cultivo de til��pia do Nilo, oreochromis niloticus, em tanques-rede no a��ude Ministro Jo��o Alves, Parelhas, Rio Grande do Norte

The dams are limnic ecosystems of great importance for its multiple uses, among them, water supply for the public and to culture of artisanal fish are most relevant. The aim of the present study is to evaluate the physical-chemical characteristics and the phytoplankton community in two chosen sites (Point 1 littoral zone of point source; Point 2 pelagic zone of non-point source) of the Minister Jo��o Alves dam, which is also known as Boqueir��o de Parelhas/RN. This represents the spatial distribution of the phytoplankton species in order to understand any possible alterations of the water quality and the phytoplankton composition in relation to the water quality originating from the impact of the tilapia, Oreochromis niloticus, culture. The study period also encompasses temporal variations exhibited in two seasons of an annual cycle, one during the dry season (Oct, Nov and Dec of 2008 and Jan of 2009), and the other rainy season (Mar, Apr, May and June of 2008) to extend the observation. The physicalchemical parameters, such as pH, temperature, electrical conductivity, concentration of dissolved oxygen were measured in situ and the values of the inorganic nutrients (nitrate, ammonium and orto-phosfato) and chlorophyll in the laboratory. The quali-quantitative analyses of the phytoplankton had been carried through sedimentation technique and the enumeration of the random of 400 cells, colonies and filaments counted using Sedgwick-Rafter counting chamber. The results of pH varied widely from the acidic to alkaline range with the minimum of 5.8 (�� 0.8) and the maximum of 9.2 (�� 0.7-0.8), at point 1 and 2. The dissolved oxygen content was higher in the rainy period than that in the dry period. The maximum electrical conductivity was of 1409 &#956;Scm-1 in point 1 and 431 minim of &#956;Scm-1, in point 2. There was a considerable alteration in the levels of inorganic nutrients such as nitrate-nitrogen, ammoniacal nitrogen and orthophosphate during the two cycles of study period. Phytoplankton assemblages presented a picture of alternate dominance among species Cyanobacteria, Bacillariophyceae and Chlorophyceae. The trophic state index diagnosed to the category of mesotrophic, which is based on the values of chlorophyll, total phosphorus and Secchi-disc measurements. The wind driven turbulence of the water column and the fresh inflow of water (flushing and dilution) during rainy season acted as constraint and did-not allow an exaggerated growth of the species of cyanobacteria. On the basis of the present we conclude that the culture of tilapias in cage-culture fails to produce pollution load that could compromise the quality of the water of the dam, probably be due to small dimension of the culture in relation to the size, volume of the water and the reservoir capacity support its own environment

Perfil espacial e temporal de poluentes nas ��guas da represa municipal de S��o Jos�� do Rio Preto, S��o Paulo, Brasil

In this manuscript, seasonal and spatial trends of water collected from two sampling places in the Preto River in the Turvo-Grande watershed were evaluated. Water samples were collected during June/07 to July/08 and parameters sulphate, total organic carbon, ammonia, conductivity, dissolved oxygen, temperature, dissolved total solids and nitrate were quantified. Seasonal trend indicated sanitary effluents as a point source of contamination in both sampling points. Vertical trends demonstrated that the Municipal Dam was not stratified and received a diffuse source of pollutants from flooding and agriculture runoffs. It was also verified that there is relatively fast ammonia consumption kinetics having a half-life time of 1.43 h which can explain the low ammonia concentrations found in these aquatic bodies.

Foreign Investment in Latin America and the Caribbean 1998

Includes bibliography

Integra����o entre um modelo de simula����o hidrol��gica e Sistema de Informa����o Geogr��fica na delimita����o de zonas tamp��o rip��rias

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Compara����o cromoss��mica intrapopulacional da esp��cie Tayassu tajacu criada em cativeiro

A esp��cie Tayassu tajacu (caititu) �� amplamente distribu��da no continente americano, distribuindo-se desde o sul dos Estados Unidos at�� o norte da Argentina. No Brasil, distribui-se por todo o territ��rio, sendo uma das principais fontes de prote��nas para as popula����es rurais. Sua cria����o em cativeiro possibilitaria uma forma de pecu��ria alternativa para essas popula����es, desta forma protegendo essa esp��cie da press��o da ca��a. Portanto, a citogen��tica serviria como uma ferramenta potencial para o monitoramento reprodutivo de animais criados em cativeiro, principalmente, quando destinados a fins comerciais. Esse trabalho tem por objetivo determinar o n��mero cromoss��mico de duas popula����es criadas em cativeiro. Para este fim, foram analisadas met��fases mit��ticas obtidas de cultura de linf��citos a partir de amostras de sangue de 6 animais oriundos de Mossor�� (RN), 1 de Ipixuna (PA) e 4 de Uruar�� (PA). A an��lise resultou no mesmo padr��o cariot��pico da esp��cie encontrado na literatura (2n = 30 cromossomos e NF = 48), al��m de corresponderem ao padr��o sulamericano da esp��cie, ou seja, sem a presen��a da transloca����o entre os cromossomos autoss��micos 1 e 8, por��m n��o foram encontradas diferen��as entre as popula����es estudadas. No entanto, foram observados polimorfismos quando comparadas a popula����es do restante do pa��s, al��m de popula����es norte americanas e da Guiana Francesa.

Empilhamento s��smico pela composi����o de ondas planas

No presente trabalho de tese �� apresentada uma nova t��cnica de empilhamento de dados s��smicos para a obten����o da se����o de incid��ncia normal ou afastamento fonte-receptor nulo, aplic��vel em meios bidimensionais com varia����es laterais de velocidade. Esta nova t��cnica denominada Empilhamento S��smico pela Composi����o de Ondas Planas (empilhamento PWC) foi desenvolvida tomando como base os conceitos f��sicos e matem��ticos da decomposi����o do campo de ondas em ondas planas. Este trabalho pode ser dividido em tr��s partes: Uma primeira parte, onde se apresenta uma revis��o da t��cnica de empilhamento s��smico convencional e do processo de decomposi����o do campo de ondas produzido a partir de fontes pontuais em suas correspondentes ondas planas. Na segunda parte, �� apresentada a formula����o matem��tica e o procedimento de aplica����o do m��todo de empilhamento s��smico pela composi����o de ondas planas. Na terceira parte se apresenta a aplica����o desta nova t��cnica de empilhamento na serie de dados Marmousi e uma analise sobre a atenua����o de ru��do. A formula����o matem��tica desta nova t��cnica de empilhamento s��smico foi desenvolvida com base na teoria do espalhamento aplicado a ondas s��smicas sob a restri����o do modelo de aproxima����o de Born. Nesse sentido, inicialmente se apresenta a determina����o da solu����o da equa����o de onda caustica para a configura����o com afastamento fonte-receptor finito, que posteriormente �� reduzido para a configura����o de afastamento fonte-receptor nulo. Por outra parte, com base nessas solu����es, a express��o matem��tica deste novo processo de empilhamento s��smico �� resolvida dentro do contexto do modelo de aproxima����o de Born. Verificou-se que as solu����es encontradas por ambos procedimentos, isto ��, por meio da solu����o da equa����o da onda e pelo processo de empilhamento proposto, s��o iguais, mostrando-se assim que o processo de empilhamento pela composi����o de ondas planas produz uma se����o com afastamento fonte-receptor nulo. Esta nova t��cnica de empilhamento basicamente consiste na aplica����o de uma dupla decomposi����o do campo de ondas em onda planas por meio da aplica����o de dois empilhamentos obl��quos (slant stack), isto �� um ao longo do arranjo das fontes e outro ao longo do arranjo dos detectores; seguido pelo processo de composi����o das ondas planas por meio do empilhamento obliquo inverso. Portanto, com base nestas opera����es e com a ajuda de um exemplo de aplica����o nos dados gerados a partir de um modelo simples, s��o descritos os fundamentos e o procedimento de aplica����o (ou algoritmo) desta nova t��cnica de obten����o da se����o de afastamento nulo. Como exemplo de aplica����o do empilhamento PWC em dados correspondentes a um meio com varia����es laterais de velocidade, foi aplicado nos dados Marmousi gerados segundo a t��cnica de cobertura m��ltipla a partir de um modelo que representa uma situa����o geol��gica real. Por compara����o da se����o resultante com a similar produzida pelo m��todo de empilhamento convencional, observa-se que a se����o de afastamento nulo desta nova t��cnica apresenta melhor defini����o e continuidade dos reflectores, como tamb��m uma melhor caracteriza����o da ocorr��ncia de difra����es. Por ��ltimo, da atenua����o de ru��do aleat��rio realizada nos mesmos dados, observa-se que esta t��cnica de empilhamento tamb��m produz uma atenua����o do ru��do presente no sinal, a qual implica um aumento na rela����o sinal ru��do.

Planejamento integrado dos recursos h��dricos na microbacia do c��rrego Tr��s Barras no munic��pio de Marin��polis-SP

P��s-gradua����o em Agronomia - FEIS

Escola, viol��ncia e trabalho infantil no Brasil

Este artigo �� um ensaio de interpreta����o que busca explicar a viol��ncia contra crian��as em nosso Pa��s a partir de alguns resultados da minha pesquisa sobre casa, trabalho e escolaridade, numa regi��o em que profundas transforma����es ajudaram a desarticular o mundo rural e desurbanizaram antigas vilas.

Impacts of urban life on water quality and fish larvae communities in two creeks of the Brazilian Amazon

Este estudo teve como objetivo investigar o impacto das atividades antropog��nicas da cidade de Bel��m pela compara����o da qualidade da ��gua e das comunidades de larvas de peixes em dois igarap��s que desembocam no rio Guam��. Um dos igarap��s atravessa um sub��rbio pobre e populoso de Bel��m, enquanto o outro �� localizado em uma ilha de Bel��m, declarada ��rea de Prote����o Ambiental desde 1997. Dois pontos de coletas foram definidos em cada igarap�� e monitorados durante oito horas, a cada tr��s meses e durante um ano. O igarap�� em regi��o urbana apresentou fortes altera����es na qualidade da ��gua, durante o ano todo e em todas as mar��s, e isto deve se essencialmente a presen��a de um elevado n��mero de coliformes termotolerantes. Poucas larvas foram encontradas. A ��gua foi considerada impr��pria para uso e atividades humanas, assim como para a vida aqu��tica. O igarap�� da ilha apresentou primeiros sinais de contamina����o por nutrientes e bact��ria durante o per��odo chuvoso, parcialmente decorrente de fontes de polui����o difusa. Em ambos os c��rregos, as comunidades larvais foram quase exclusivamente compostas de clupeiformes. Todos os est��gios de desenvolvimento larval foram encontrados. Densidades e propor����es mais elevadas de larvas rec��m eclodidas foram registradas durante a esta����o seca e associadas �� presen��a de nitrato. Resultados apontam a necessidade de desenvolver um sistema de drenagem urbano para esgoto e ��gua pluvial na maior brevidade, e recomenda um estudo de monitoramento integrado do igarap�� na ��rea de Prote����o Ambiental.

Polarimetry of the binary PDS 144

Aims. Our goal is to study the circumstellar environment associated with each component of the wide intermediate-mass pre-main sequence binary system PDS 144 using broadband polarimetry. Methods. We present near-infrared (NIR) linear polarimetric observations of PDS 144 gathered with the IAGPOL imaging polarimeter along with the CamIV infrared camera at the Observatorio do Pico dos Dias (OPD). In addition, we re-analyzed OPD archive optical polarization to separate the binary and estimate the interstellar polarization using foreground stars. Results. After discounting the interstellar component, we found that both stars of the binary system are intrinsically polarized. The polarization vectors at optical and NIR bands of both components are aligned with the local magnetic field and the jet axis. These findings indicate an interplay between the interstellar magnetic field and the formation of the binary system. We also found that the PDS 144N is less polarized than its southern companion in the optical. However, in the NIR PDS 144N is more polarized. Our polarization data can only be explained by high inclinations (i greater than or similar to 80 degrees) for the disks of both members. In particular, comparisons of our NIR data with young stellar objects disk models suggest predominantly small grains in the circumstellar environment of PDS 144N. In spite of the different grain types in each component, the infrared spectral indexes indicate a coeval system. We also found evidence of coplanarity between the disks.