Oil reaching the coast: Is Brazil on the route of international oceanic dumping?

After the oil spill disaster occurred in 2019, various events of tar balls reaching the Brazilian coast and archipelagos have been reported. The hypothesis here is that the oil/waste dumped in international waters by ships on-route to Cape of Good Hope is reaching the Brazilian coast. On that account, 30-year probabilistic simulations were used to estimate the probability of dumped oil residue reaching the Brazilian coast. The simulations considered three Zones following the South Atlantic route. The results have shown that up to 28.5 % of large ships could dump oil on-route. Inside the Brazilian Exclusive Economic Zone, the probability of dumped oil/waste reaching the coastline is about 62 % and quickly decreases for Dumping Zones 2 and 3. Equatorial and Northeast shores of Brazil are the most vulnerable to oceanic dumping when compared to other regions.

Mysterious oil spill on the Brazilian coast - Part 2: A probabilistic approach to fill gaps of uncertainties.

Over 5000 tons of spilled oil reached the northeast coast of Brazil in 2019. The Laboratory for Computational Methods in Engineering (LAMCE/COPPE/UFRJ) employed time-reverse modeling and identify multiple potential source areas. As time-reverse modeling has many uncertainties, this article carried out a methodology study to mitigate them. A probabilistic modeling using Monte Carlo approach was developed to test these source areas with the Spill, Transport, and Fate Model (STFM) and a scenario tree methodology was used to select possible spill scenarios. To estimate the performance of Lagrangian models, two new model performance evaluations were added to Chang and Hanna (2004). The combination of probabilistic simulations, scenario tree analysis, and model performance evaluation proved to be a powerful tool for mitigating the uncertainties of time-reverse modeling, yielding good results and simple implementation.

Modelagem de plumas de efluentes entre Praia Grande e Peruíbe, litoral do estado de São Paulo, Brasil / Modeling effluent plumes between Praia Grande and Peruíbe, São Paulo State's shore, Brazil

RESUMO O presente trabalho teve como objetivo monitorar a dispersão de plumas de efluentes provenientes dos emissários submarinos de Praia Grande e do Rio Itanhaém, por meio do processamento do modelo Delft3D (módulos hidrodinâmico e de qualidade da água) e do modelo Visual Plumes (módulo UM3). A modelagem de campo próximo indicou que as correntes geradas pelo vento foram mais eficientes do que as correntes de maré na diluição inicial das plumas dos emissários; e a modelagem de campo distante, validada qualitativamente, demonstrou que as concentrações dos potenciais poluentes de todas as plumas simuladas não ultrapassam os limites máximos estabelecidos pelo Conselho Nacional do Meio Ambiente quando essas plumas atingem as praias da região de estudo.

ABSTRACT This study's goal was to monitor the dispersion of effluent plumes from the Praia Grande's submarine outfalls and from the Itanhaém River by processing the Delft3D model (hydrodynamic and water quality modules) and the Visual Plumes model (UM3 module). The near field modeling indicated that wind-driven currents were more efficient than tidal currents in the initial dilution of the outfalls' plumes; and the far field modeling, qualitatively validated, demonstrated that the potential pollutants' concentrations in all the simulated plumes don't exceed the maximum limits established by the National Environmental Council when these plumes reach the study region's beaches.

3D Patterning of Si by Contact Etching With Nanoporous Metals.

Nanoporous gold and platinum electrodes are used to pattern n-type silicon by contact etching at the macroscopic scale. This type of electrode has the advantage of forming nanocontacts between silicon, the metal and the electrolyte as in classical metal assisted chemical etching while ensuring electrolyte transport to and from the interface through the electrode. Nanoporous gold electrodes with two types of nanostructures, fine and coarse (average ligament widths of ~30 and 100 nm, respectively) have been elaborated and tested. Patterns consisting in networks of square-based pyramids (10 × 10 µm2 base × 7 µm height) and U-shaped lines (2, 5, and 10 µm width × 10 µm height × 4 µm interspacing) are imprinted by both electrochemical and chemical (HF-H2O2) contact etching. A complete pattern transfer of pyramids is achieved with coarse nanoporous gold in both contact etching modes, at a rate of ~0.35 µm min-1. Under the same etching conditions, U-shaped line were only partially imprinted. The surface state after imprinting presents various defects such as craters, pores or porous silicon. Small walls are sometimes obtained due to imprinting of the details of the coarse gold nanostructure. We establish that np-Au electrodes can be turned into "np-Pt" electrodes by simply sputtering a thin platinum layer (5 nm) on the etching (catalytic) side of the electrode. Imprinting with np Au/Pt slightly improves the pattern transfer resolution. 2D numerical simulations of the valence band modulation at the Au/Si/electrolyte interfaces are carried out to explain the localized aspect of contact etching of n-type silicon with gold and platinum and the different surface state obtained after patterning. They show that n-type silicon in contact with gold or platinum is in inversion regime, with holes under the metal (within 3 nm). Etching under moderate anodic polarization corresponds to a quasi 2D hole transfer over a few nanometers in the inversion layer between adjacent metal and electrolyte contacts and is therefore very localized around metal contacts.

Modelagem da dispersão de coliformes termotolerantes e enterococos em duas enseadas na região costeira de Ubatuba (SP), Brasil / Modeling of the dispersion of thermotolerant coliforms and enterococci in two bays in the coastal region of Ubatuba (SP), Brazil

RESUMO Foram avaliados os efeitos de ações antrópicas sobre o sistema costeiro de Ubatuba (SP) através de modelos que descrevem os mecanismos e as reações envolvidas na dispersão de indicadores microbiológicos (coliformes termotolerantes e enterococos) na água do mar. A análise da qualidade das águas destinadas à recreação, além de ser uma ação importante em termos de saúde pública, também se justifica em vista da importância da atividade turística em Ubatuba, possuindo, ainda, grande relevância para o planejamento ambiental. Na modelagem, foram utilizados os módulos do sistema Delft3D. No módulo de qualidade da água, foram estudados os mecanismos de dispersão dos poluentes, a partir da associação de dados de poluição com os resultados do módulo hidrodinâmico, em duas enseadas em Ubatuba (SP): Flamengo e Palmas. Os resultados obtidos permitem afirmar que o sistema de correntes nas enseadas, determinado pela geomorfologia da região, não confere alta capacidade de diluição e dispersão de efluentes na área de estudo. Todavia, a circulação marinha e os processos envolvidos no decaimento das bactérias são suficientes para difundir e diminuir suas concentrações ao longo das enseadas. Concluiu-se que a modelagem ambiental reproduziu de maneira satisfatória os processos envolvidos no transporte e na difusão de indicadores microbiológicos, contribuindo com os estudos sobre os efeitos das atividades antrópicas no sistema costeiro de Ubatuba.

ABSTRACT The effects of human activities on the coastal system of Ubatuba (SP) were evaluated through models that describe the mechanisms and reactions involved in the dispersal of microbiological indicators (thermotolerant coliforms and enterococci) in seawater. Analysis of the quality of water intended for recreation as well as being an important action in terms of public health, is also justified in view of the importance of tourism in Ubatuba, having also great importance to environmental planning. In modeling, the modules Delft3D system were used. In the water quality module, the pollutants dispersal mechanisms were studied, from the association of pollution data with the results of the hydrodynamic module, in two bays in Ubatuba: Flamengo and Palmas. The results allow us to state that the system of currents, determined by the geomorphology of the area, does not provide high capacity for dilution and dispersion of effluents in the study area. However, the marine circulation and the processes involved in the decay of bacteria are enough to spread and reduce their concentrations along the bays. It was concluded that environmental modeling reproduced satisfactorily the processes involved in the transport and diffusion of microbiological indicators, contributing to the studies on the effects of human activities on the coastal system of Ubatuba.

Tunable Surface Structuration of Silicon by Metal Assisted Chemical Etching with Pt Nanoparticles under Electrochemical Bias.

An in-depth study of metal assisted chemical etching (MACE) of p-type c-Si in HF/H2O2 aqueous solutions using Pt nanoparticles as catalysts is presented. Combination of cyclic voltammetry, open circuit measurements, chronoamperometry, impedance spectroscopy, and 2D band bending modeling of the metal/semiconductor/electrolyte interfaces at the nanoscale and under different etching conditions allows gaining physical insights into this system. Additionally, in an attempt to mimic the etching conditions, the modeling has been performed with a positively biased nanoparticle buried in the Si substrate. Following these findings, the application of an external polarization during etching is introduced as a novel efficient approach for achieving straightforward control of the pore morphology by acting upon the band bending at the Si/electrolyte junction. In this way, nanostructures ranging from straight mesopores to cone-shaped macropores are obtained as the Si sample is biased from negative to positive potentials. Remarkably, macroscopic cone-shaped pores in the 1-5 µm size range with a high aspect ratio (L/W ∼ 1.6) are obtained by this method. This morphology leads to a reduction of the surface reflectance below 5% over the entire VIS-NIR domain, which outperforms macrostructures made by state of the art texturization techniques for Si solar cells.

Impact of the Smoothened inhibitor, IPI-926, on smoothened ciliary localization and Hedgehog pathway activity.

A requisite step for canonical Hedgehog (Hh) pathway activation by Sonic Hedgehog (Shh) ligand is accumulation of Smoothened (Smo) to the primary cilium (PC). Activation of the Hh pathway has been implicated in a broad range of cancers, and several Smo antagonists are being assessed clinically, one of which is approved for the treatment of advanced basal cell carcinoma. Recent reports demonstrate that various Smo antagonists differentially impact Smo localization to the PC while still exerting inhibitory activity. In contrast to other synthetic small molecule Smo antagonists, the natural product cyclopamine binds to and promotes ciliary accumulation of Smo and "primes" cells for Hh pathway hyper-responsiveness after compound withdrawal. We compared the properties of IPI-926, a semi-synthetic cyclopamine analog, to cyclopamine with regard to potency, ciliary Smo accumulation, and Hh pathway activity after compound withdrawal. Like cyclopamine, IPI-926 promoted accumulation of Smo to the PC. However, in contrast to cyclopamine, IPI-926 treatment did not prime cells for hyper-responsiveness to Shh stimulation after compound withdrawal, but instead demonstrated continuous inhibition of signaling. By comparing the levels of drug-induced ciliary Smo accumulation with the degree of Hh pathway activity after compound withdrawal, we propose that a critical threshold of ciliary Smo is necessary for "priming" activity to occur. This "priming" appears achievable with cyclopamine, but not IPI-926, and is cell-line dependent. Additionally, IPI-926 activity was evaluated in a murine tumor xenograft model and a pharmacokinetic/pharmacodynamic relationship was examined to assess for in vivo evidence of Hh pathway hyper-responsiveness. Plasma concentrations of IPI-926 correlated with the degree and duration of Hh pathway suppression, and pathway activity did not exceed baseline levels out to 96 hours post dose. The overall findings suggest that IPI-926 possesses unique biophysical and pharmacological properties that result in Hh pathway inhibition in a manner that differentiates it from cyclopamine.

Design, optimization and fabrication of an optical mode filter for integrated optics.

We present the design, optimization, fabrication and characterization of an optical mode filter, which attenuates the snaking behavior of light caused by a lateral misalignment of the input optical fiber relative to an optical circuit. The mode filter is realized as a bottleneck section inserted in an optical waveguide in front of a branching element. It is designed with Bézier curves. Its effect, which depends on the optical state of polarization, is experimentally demonstrated by investigating the equilibrium of an optical splitter, which is greatly improved however only in TM mode. The measured optical losses induced by the filter are 0.28 dB.

Prognostic Factors for Injection-Site Sarcomas in Cats.

In this retrospective study of cases from Italy and Switzerland, the clinical features of injection-site sarcomas in 57 cats were reviewed. In addition to routine physical, laboratory, and radiographic examinations, advanced imaging (computed tomographic scans) was conducted to delineate tumor extent. Treatment was by wide surgical excision including partial scapulectomy, spinous process removal, and amputation (appendicular lesions). Radiotherapy and chemotherapy were also used. The results revealed that cats with grade 3 tumors were most likely to develop distant pulmonary metastases (and to have shorter survival rates); this occurred in 21% of the cases.Median follow-up for cats that survived (51%) was 600 days; for those that died (49%), it was 272 days. In this study, tumor size, as measured manually by calipers, was not a prognostic factor. Furthermore, factors associated with local recurrence were not identified. The authors recognized the limitations of a retrospective study, especially with regard to treatments before referral.

Treatments for feline long bone fractures.

Orthopedic injuries in cats occur frequently and are amenable to a variety of surgical and nonsurgical treatment options. Complications and delayed healing have been reported and can be attributed to improper fixation. Clinicians have numerous options ranging from external to internal fixation, casting, cage rest, and limb amputation. The goals of reducing patient morbidity and obtaining a return to normal function warrant the selection of an appropriate treatment based on the nature of the lesion, available expertise, and directives of the client.