Limit laws of entrance times for low complexity Cantor minimal systems

This paper is devoted to the study of limit laws of entrance times to cylinder sets for Cantor minimal systems of zero entropy using their representation by means of ordered Bratteli diagrams. We study in detail substitution subshifts and we prove these limit laws are piecewise linear functions. The same kind of results is obtained for classical low complexity systems given by non stationary ordered Bratteli diagrams

<i>Schistosoma mansoni</i> cercariae experience influx of macromolecules during skin penetration

We have observed that when cercariae penetrate the skin of mice, there is influx into their tissues of Lucifer Yellow and certain labelled molecules of up to 20 kDa molecular weight. This observation was made using a variety of fluorescent membrane-impermeant compounds injected into the skin before the application of cercariae. This unexpected phenomenon was investigated further by transforming cercariae in vitro in the presence of the membrane-impermeant compounds and examining the distribution by microscopy. In schistosomula derived from this procedure, the nephridiopore and surface membrane were labelled while the pre- and post-acetabular glands were not labelled. The region associated with the oesophagus within the pharyngeal muscle clearly contained the fluorescent molecules, as did the region adjacent to the excretory tubules and the germinal mass. We used cercariae stained with carmine to aid identification of regions labelled with Lucifer Yellow. Although the mechanism of this influx is unclear, the observation is significant. From it, we can suggest an hypothesis that, during skin penetration, exposure of internal tissues of the parasite to external macromolecules represents a novel host-parasite interfac

Second Mesiobuccal Canal Treatment in a Predoctoral Dental Clinic: A Retrospective Clinical Study

The aim of this retrospective clinical study was to evaluate the location and treatment of second canals in mesiobuccal roots (MB2) of first and second maxillary molars in a predoctoral endodontic clinic by the graduating classes of 2008 to 2015. These results were compared to similar clinical studies. Included in the study were 368 root canal treatments performed by 310 third- and fourth-year dental students at one U.S. dental school. All cases were done under faculty supervision, and the students were instructed to use dental loupe magnification. Students' evaluation sheets were used to deteremine the total MB2 canals treated in first and second maxillary molars. The results showed that, overall, 72.55% of the teeth had an MB2 canal treated. The frequency was higher in first molars (75.91%) than in second molars (56.92%) (p0.05). Under proper supervision by experienced endodontists, these dental students were capable of treating MB2 canals in maxillary molars. The frequency of MB2 canals located and treated by dental students with the assistance of experienced professionals was higher in first than in second molars. No significant difference was found between third- and fourth-year students. The incidence of MB2 canals located and treated in this study was found to be similar to that in other clinical studies

Estudo da aclimatação de lodo ativado com efluente “in natura” da industria de pescado

O presente trabalho estudou a adaptação e a atividade do lodo biológico procedente de um reator UASB de uma estação de tratamento de efluentes de uma indústria de processamento de pescado, para remoção biológica de nitrogênio em um Reator Batelada Seqüencial instrumentado em escala de bancada. A adaptação consistiu em aumento seqüencial da carga aplicada nas razões volumétricas efluente in natura : efluente sintético de 1:3,33; 1:2,5; 1:2,0; sendo a concentração inicial de inóculo empregada de 20 g SSV/L. Durante este período foram acompanhadas as variações de DQO, nitrato e amônia, onde se obteve uma remoção de até 80% da carga orgânica do efluente e de até 97% da matéria nitrogenada. O experimento com diluição de 1:3,33 foi realizado com adição de 0,5 % de sal para avaliar o efeito da salinidade, o qual também é considerado na análise dos resultados obtidos

Yarrowia lipolytica : an industrial workhorse

Yarrowia lipolytica is one of the most extensively studied ‘‘non-conventional’’ yeasts, being a strictly aerobic microorganism capable of producing important metabolites and having an intense secretory activity, which justifies efforts to use it in industry (as a biocatalyst), in molecular biology and in genetics studies. Moreover, Y. lipolytica has been considered an adequate model for dimorphism studies in yeasts. Yarrowia lipolytica presents the ability to grow on Olive Mill Wastewater (OMW) as well as to degradate organic compounds, including aliphatic and aromatic hydrocarbons, often accompanied by biosurfactants production. One of the most important products secreted by this microorganism is lipase which can be exploited for several applications in the detergent, food, pharmaceutical, and environmental industries. In addition, Y. lipolytica is able to produce citric acid and aroma from a variety of carbon sources, including sugars, alkanes, plant oils, starch hydrolysates, ethanol, and glycerol. Thus, this chapter presents an overview of Yarrowia lipolytica features and its major biotechnological applications

Estudo da aclimatação da flora microbiana a concentrações crescentes de efluente “in natura” da indústria de pescado em reator batelada sequencial

O presente trabalho estudou a adaptação e a atividade do lodo biológico procedente de um reator UASB de uma estação de tratamento de efluentes de uma indústria de processamento de pescado, para remoção biológica de nitrogênio em um Reator Batelada Seqüencial. A adaptação consistiu em aumento seqüencial da carga aplicada nas razões volumétricas efluente in natura : efluente sintético de 1:3,33; 1:2,5; 1:2,0; sendo a concentração inicial de inóculo empregada de 20 g SSV/L. Durante este período foram acompanhadas as variações de DQO, nitrato e amônia, onde se obteve uma remoção de até 80% da carga orgânica do efluente e de até 97% da matéria nitrogenada. O experimento com diluição de 1:3,33 foi conduzido com adição de 0,5 % de sal (NaCl) para avaliar o efeito da salinidade, o qual também é considerado na análise dos resultados obtidos.The present work analyzes the adaptation and activity of a sludge belonging to a UASB reactor of the wastewater treatment unit from a fish processing industry, in a bench scale Sequencing Batch Reactor for biological nitrogen removal. The sludge adaptation was carried using an increasing sequence of the applied load from 1:3.33; 1:2.5; 1:2.0; regarding to volume of in natura wastewater : synthetic sewage. The initial inocullum concentration employed was 20 g VSS / L. During this period COD, nitrate and ammonia concentrations were followed and a removal about 80% of the organic matter and up to 97% of nitrogen could be achieved. An experiment employing the greater dilution (1:3.33) with 0.5% salt (as NaCl) was also carried to evaluate the salinity effect which is considered in the analysis of the results herein presented

Efeito do sal no desempenho de um reator batelada sequencial

Neste trabalho investigou-se o desempenho de um Reator Batelada Sequencial no tratamento de efluentes salinos (0,5 a 6,0%) utilizando uma estratégia de enchimento por pulsos simétricos. Verificou-se que com a estratégia adotada se obtiveram elevadas porcentagens de remoção de amónia (acima de 70%) evidenciando a elevada eficiência do reator batelada sequencial no processo de nitrificação. Contudo, para 0,5 e 1,0% de sal a remoção de amónia diminuiu indicando que a influência do choque de adição de sal é maior no início da etapa de aclimatação da biomassa. Apesar de ter sido observado um aumento da concentração de biomassa dentro do reator durante o período estudado, as porcentagens de remoção de DQO diminuíram com o aumento da concentração de sal no efluente, apontando um efeito inibitório do sal. A diminuição do IVL com o aumento da concentração de sal indica a sedimentação dos flocos menos compactos, enquanto que o aumento da turbidez demonstra uma maior quantidade de sólidos suspensos no efluente tratado.The work aims to evaluate a Sequencing Batch Reactor performance treating with saline wastewater (0,5 to 6,0%) employing a filling strategy with symmetric pulses. It was verified that the adopted operational strategy provides ammoniacal nitrogen removal rates over than 70%, demonstrating the high efficiency of this reactor in the nitrification process. Nevertheless, amonia removal rate lowered for 0,5 and 1,0% NaCl, indicating that the influence of salt addition is more significant in the early biomass acclimation stages. Although it was observed an increase in biomass concentration inside the reactor along the operation period, the removal indexes for COD diminishes with salt concentration increase, denoting somehow an inhibitory effect. Lower SVI were achieved with an increase in salt concentration leading to the settling of less compact sludge, while higher turbidity reveals na increase in the suspended solids in the treated effluent