2,118 research outputs found

    TRATAMENTO DE ÁGUAS RESIDUÁRIAS TÊXTEIS PELO PROCESSO DE ADSORÇÃO SEGUIDO DE COAGULAÇÃO/FLOCULAÇÃO

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    Dentre os mĂ©todos de tratamento disponĂ­veis para ĂĄguas residuĂĄrias tĂȘxteis tĂȘm-se o processo de adsorção/coagulação/floculação. Com isto, o presente estudo buscou caracterizar as ĂĄguas residuĂĄrias de uma lavanderia industrial tĂȘxtil (situada no meio oeste catarinense) e analisar a eficiĂȘncia do tratamento por adsorção com carvĂŁo ativado (CA), seguido de coagulação/floculação empregando o coagulante tanino. O estudo transcorreu no LEMA (UNOESC Videira). Sendo, que para os procedimentos metodolĂłgicos testou-se 1 g de CA, para cada volume de tanino (1 e 2 mL) em 1 L de amostra. Os ensaios foram realizados em equipamento Jar-test, onde: inicialmente assumiu-se tempo de 1 hora (100 r.p.m) para a incorporação do CA as ĂĄguas, seguido da adição do coagulante (20 minutos a 100 r.p.m) e correção do pH (±7) com hidrĂłxido de cĂĄlcio. Por fim, adicionou-se 2 mL de polĂ­mero catiĂŽnico (20 min a 50 r.p.m.). ApĂłs a filtração das amostras, realizaram-se as seguintes anĂĄlises: cor (mg Pt Co/L), turbidez (NTU), DQO (mg/L), nitrogĂȘnio amoniacal (mg/L) e fosfato (mg/L). Ao tĂ©rmino do estudo, para as ĂĄguas brutas obtiveram-se valores mĂ©dios de: pH 6,07; cor 832,2; turbidez 3,65; DQO 462,33; nitrogĂȘnio 4,03 e fosfato 11,12. JĂĄ em relação Ă  eficiĂȘncia dos tratamentos alcançou-se 99,3% e 99,6% de remoção de turbidez; 98,6% e 97,4% de cor; 62,9% e 72,53% para fosfato, 58,1% e 38,7% de DQO e acrĂ©scimo de 5,05 e 6,03 mg/L de nitrogĂȘnio na ĂĄgua tratada, para os volumes de 1 e 2 mL tanino, respectivamente. Perante esses resultados concluiu-se que o volume de 1 mL tanino apresentou melhores resultados

    Fine-Scale Variation in Vector Host Use and Force of Infection Drive Localized Patterns of West Nile Virus Transmission

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    The influence of host diversity on multi-host pathogen transmission and persistence can be confounded by the large number of species and biological interactions that can characterize many transmission systems. For vector-borne pathogens, the composition of host communities has been hypothesized to affect transmission; however, the specific characteristics of host communities that affect transmission remain largely unknown. We tested the hypothesis that vector host use and force of infection (i.e., the summed number of infectious mosquitoes resulting from feeding upon each vertebrate host within a community of hosts), and not simply host diversity or richness, determine local infection rates of West Nile virus (WNV) in mosquito vectors. In suburban Chicago, Illinois, USA, we estimated community force of infection for West Nile virus using data on Culex pipiens mosquito host selection and WNV vertebrate reservoir competence for each host species in multiple residential and semi-natural study sites. We found host community force of infection interacted with avian diversity to influence WNV infection in Culex mosquitoes across the study area. Two avian species, the American robin (Turdus migratorius) and the house sparrow (Passer domesticus), produced 95.8% of the infectious Cx. pipiens mosquitoes and showed a significant positive association with WNV infection in Culex spp. mosquitoes. Therefore, indices of community structure, such as species diversity or richness, may not be reliable indicators of transmission risk at fine spatial scales in vector-borne disease systems. Rather, robust assessment of local transmission risk should incorporate heterogeneity in vector host feeding and variation in vertebrate reservoir competence at the spatial scale of vector-host interaction

    Cutaneous Leishmaniasis and Sand Fly Fluctuations Are Associated with El Nino in Panama

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    BackgroundCutaneous Leishmaniasis (CL) is a neglected tropical vector-borne disease. Sand fly vectors (SF) and Leishmania spp parasites are sensitive to changes in weather conditions, rendering disease transmission susceptible to changes in local and global scale climatic patterns. Nevertheless, it is unclear how SF abundance is impacted by El Nino Southern Oscillation (ENSO) and how these changes might relate to changes in CL transmission.Methodology and FindingsWe studied association patterns between monthly time series, from January 2000 to December 2010, of: CL cases, rainfall and temperature from Panama, and an ENSO index. We employed autoregressive models and cross wavelet coherence, to quantify the seasonal and interannual impact of local climate and ENSO on CL dynamics. We employed Poisson Rate Generalized Linear Mixed Models to study SF abundance patterns across ENSO phases, seasons and eco-epidemiological settings, employing records from 640 night-trap sampling collections spanning 2000?2011. We found that ENSO, rainfall and temperature were associated with CL cycles at interannual scales, while seasonal patterns were mainly associated with rainfall and temperature. Sand fly (SF) vector abundance, on average, decreased during the hot and cold ENSO phases, when compared with the normal ENSO phase, yet variability in vector abundance was largest during the cold ENSO phase. Our results showed a three month lagged association between SF vector abundance and CL cases.ConclusionAssociation patterns of CL with ENSO and local climatic factors in Panama indicate that interannual CL cycles might be driven by ENSO, while the CL seasonality was mainly associated with temperature and rainfall variability. CL cases and SF abundance were associated in a fashion suggesting that sudden extraordinary changes in vector abundance might increase the potential for CL epidemic outbreaks, given that CL epidemics occur during the cold ENSO phase, a time when SF abundance shows its highest fluctuations

    Brain iron accumulation in unexplained fetal and infant death victims with smoker mothers-The possible involvement of maternal methemoglobinemia

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    <p>Abstract</p> <p>Background</p> <p>Iron is involved in important vital functions as an essential component of the oxygen-transporting heme mechanism. In this study we aimed to evaluate whether oxidative metabolites from maternal cigarette smoke could affect iron homeostasis in the brain of victims of sudden unexplained fetal and infant death, maybe through the induction of maternal hemoglobin damage, such as in case of methemoglobinemia.</p> <p>Methods</p> <p>Histochemical investigations by Prussian blue reaction were made on brain nonheme ferric iron deposits, gaining detailed data on their localization in the brainstem and cerebellum of victims of sudden death and controls. The Gless and Marsland's modification of Bielschowsky's was used to identify neuronal cell bodies and neurofilaments.</p> <p>Results</p> <p>Our approach highlighted accumulations of blue granulations, indicative of iron positive reactions, in the brainstem and cerebellum of 33% of victims of sudden death and in none of the control group. The modified Bielschowsky's method confirmed that the cells with iron accumulations were neuronal cells.</p> <p>Conclusions</p> <p>We propose that the free iron deposition in the brain of sudden fetal and infant death victims could be a catabolic product of maternal methemoglobinemia, a biomarker of oxidative stress likely due to nicotine absorption.</p
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