Combined effects of diesel and air exposure on oxidative stress parameters of mussels Perna perna (Mytilidae, Bivalvia).

This study aimed to assess the combined effect of hypoxia and exposure to diesel on biochemical parameters of Perna perna mussels. Mussels previously kept for 48 h in clean seawater were submitted to hypoxia for 24 h followed by reoxygenation in clean seawater for 48 h. The same procedure was done but using seawater containing 0.01 mL/L of diesel, before and after hypoxia. Antioxidant enzymes as well as levels of glutathione and lipid peroxidation were measured in gills and digestive glands. The neutral red retention time assay was also evaluated in hemocytes. Results showed that cycles of air exposure and reoxygenation caused oxidative stress and antioxidant modulation in both the gills and digestive glands. The presence of diesel in water triggered additional modulation of antioxidants under hypoxia and reoxygenation stress, apparently enhancing the capacity of mussels to avoid lipid peroxidation.

Sub-lethal combined effects of illicit drug and decreased pH on marine mussels: A short-time exposure to crack cocaine in CO2 enrichment scenarios.

The increasing CO2-concentrations in the atmosphere promote ocean acidification. Seawater chemistry changes interact with contaminants, such as illicit drugs in the coastal zones. This work evaluates impacts of pH decrease and crack-cocaine exposure on the commercial mussel Perna perna through biomarker responses (lysosomal membrane stability, lipid peroxidation, and DNA strand breaks). The organisms were exposed to different crack-cocaine concentrations (0.5, 5.0, and 50 µg L-1) combined with different pH values (8.3, 8.0, 7.5, 7.0, 6.5, and 6.0) for 96 h. Crack-cocaine in the different acidification scenarios triggered cyto-genotoxicity, which affected the overall health of mussels exposed to cocaine environmentally relevant concentration. This study produced the first data on biomarker responses associated with CO2-induced acidification and illicit drugs (crack-cocaine) in marine organisms.

Mussels get higher: A study on the occurrence of cocaine and benzoylecgonine in seawater, sediment and mussels from a subtropical ecosystem (Santos Bay, Brazil).

Data on the occurrence of cocaine (COC) and benzoylecgonine (BE) in marine environmental compartments are still limited, with few studies reporting superficial water contamination, mainly in tropical zones. In this sense, environmental data of these substances are essential to identify potential polluting sources, as well as their impact in costal ecosystems. The aim of this study was to evaluate the occurrence of COC and BE in seawater, sediment and mussels from a subtropical coastal zone (Santos Bay, São Paulo, Brazil), as well as to determine a field measured Bioaccumulation Factor (BAF). COC and BE were detected in all water samples in concentrations ranging from 1.91 ng·L-1 to 12.52 ng·L-1 and 9.88 ng·L-1 to 28.53 ng·L-1, respectively. In sediments, only COC was quantified in concentrations ranging from 0.94 ng·g-1 to 46.85 ng·g-1. Similarly, only COC was detected in tissues of mussels 0.914 µg·kg-1 to 4.58 µg·kg-1 (ww). The field-measured BAF ranged from 163 to 1454 (L·kg-1). Our results pointed out a widespread contamination by cocaine and its main human metabolite benzoylecgonine in Santos Bay. Mussels were able to accumulate COC in areas used by residents and tourists for bathing, fishing, and harvest, denoting concern to human health. Therefore, our data can be considered a preliminary assessment, which indicates the need to evaluate drugs (including illicit as COC) in environmental and seafood monitoring programs, in order to understand their risks on the ecosystem and human health.

Seasonal monitoring of cocaine and benzoylecgonine in a subtropical coastal zone (Santos Bay, Brazil).

Illicit drugs and their metabolites represent a new class of emerging contaminants. These substances are continuously discharged into wastewater which have been detected in the aquatic environment in concentrations ranging from ng.L-1 to µg.L-1. Our study detected the occurrence of cocaine (COC) and benzoylecgonine (BE) in a subtropical coastal zone (Santos Bay, SP, Brazil) within one year. Water samples (surface and bottom) were collected from the Santos Submarine Sewage Outfall (SSOS) area. COC and BE were measured in the samples using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-ESI-MS/MS). Concentrations ranged from 12.18 to 203.6 ng.L-1 (COC) and 8.20 to 38.59 ng.L-1 (BE). Higher concentrations of COC were observed during the end of spring, following the population increase at summer season. COC and its metabolite occurrence in this coastal zone represent a threat to coastal organisms.

Harmful effects of cocaine byproduct in the reproduction of sea urchin in different ocean acidification scenarios.

This study has as main objective assessing the toxicity of crack-cocaine combined with different scenarios of ocean acidification on fertilization rate and embryo-larval development of Echinometra lucunter sea urchin. Effects on early life stages were assessed at five different concentrations (6,25 mg.L-1; 12,5 mg.L-1; 25 mg.L-1; 50 mg.L-1 and 100 mg.L-1) of crack-cocaine at four different pH values (8.5; 8.0; 7.5; 7.0). The pH values were achieved using two different methodologies: adding hydrochloric acid (HCl) and injecting carbon dioxide (CO2). The fertilization test did not show significant differences (p ≤ 0.05) compared with control sample at pH values 8.5; 8.0 and 7.5. Results of embryo-larval assays showed a half maximal effective concentration (EC50) of crack-cocaine at pH values tested (8.5, 8.0, 7.5) as 58.83, 10.67 and 11.58 mg/L-1 for HCl acidification and 58.83, 23.28 and 12.57 mg/L-1 for CO2 enrichment. At pH 7.0 the effects observed in fertilization rate and embryo development were associated with the acidification. This study is the first ecotoxicological assessment of illicit drug toxicity in aquatic ecosystems at different ocean acidification scenarios.

Marine contamination and cytogenotoxic effects of fluoxetine in the tropical brown mussel Perna perna.

Concerns are growing about the presence of fluoxetine (FLX) in environmental matrices, as well as its harmful effects on non-target organisms. FLX in aquatic ecosystems has been detected in a range varying from pg/L to ng/L, while adverse effects have been reported in several organisms inhabiting freshwater and marine environments. The present study quantifies FLX concentrations in seawater samples from Santos Bay, Brazil and assesses metabolic responses and sublethal effects on the tropical brown mussel Perna perna. Levels of ethoxyresorufin­O­deethylase, dibenzylfluorescein dealkylase, glutathione S-transferase, glutathione peroxidase, cholinesterase, lipoperoxidation, and DNA damage were assessed in the gills and digestive gland of these animals, and lysosomal membrane stability was also assessed in hemocytes. FLX altered phase I and II enzyme activities, caused cytogenotoxic effects, and negatively impacted the overall health of mussels exposed to environmentally relevant concentrations. These findings contribute to characterize the risks of introducing this drug into the marine environment.

Ecotoxicological effects of losartan on the brown mussel Perna perna and its occurrence in seawater from Santos Bay (Brazil).

The antihypertensive losartan (LOS) has been detected in wastewater and environmental matrices, however further studies focused on assessing the ecotoxicological effects on aquatic ecosystems are necessary. Considering the intensive use of this pharmaceutical and its discharges into coastal zones, our study aimed to determine the environmental concentrations of LOS in seawater, as well as to assess the biological effects of LOS on the marine bivalve Perna perna. For this purpose, fertilization rate and embryolarval development were evaluated through standardized assays. Phase I (ethoxyresorufin O­deethylase EROD and dibenzylfluorescein dealkylase DBF) and II (glutathione S-transferase GST) enzymes, glutathione peroxidase (GPx), Cholinesterase (ChE), lipoperoxidation (LPO) and DNA damage were used to analyze sublethal responses in gills and digestive gland of adult individuals. Lysosomal membrane stability was also assessed in hemocytes. Our results showed the occurrence of LOS in 100% of the analyzed water samples located in Santos Bay, Sao Paulo, Brazil, in a range of 0.2 ng/L-8.7 ng/L. Effects on reproductive endpoints were observed after short-term exposure to concentrations up to 75 mg/L. Biomarker responses demonstrated the induction of CYP450 like activity and GST in mussel gills exposed to 300 and 3000 ng/L of LOS, respectively. GPx activity was also increased in concentration of exposure to 3000 ng/L of LOS. Cyto-genotoxic effects were found in gills and hemocytes exposed in concentrations up to 300 ng/L. These results highlighted the concern of introducing this class of contaminants into marine environments, and pointed out the need to include antihypertensive compounds in environmental monitoring programs.

Recreating Intestinal Peristalsis in the Petri Dish.

Here we describe a culture technique of cells dissociated from the external muscularis of the guinea pig small intestine, which allows us to maintain all the elements involved in the intestinal peristaltic reflex. After a few days in culture, these cells reorganize to form a small group of cells that permit the generation of pacemaker activity, spontaneous contractions, and the development of inhibitory and excitatory junction potentials in the petri dish, all elements involved in the peristaltic reflex. Therefore, these co-cultures are suitable to study the cellular and molecular aspects related to the development, maintenance, and modulation of motor intestinal functions.

Análise da qualidade sanitária da areia das praias de Santos, litoral do estado de São Paulo / Analysis of sand quality health in Santos beach, coast of São Paulo state

RESUMO: Em Santos, litoral de São Paulo, a avaliação da qualidade microbiológica da água das praias é realizada pela prefeitura e pela Companhia Ambiental do Estado de São Paulo (CETESB). Entretanto, a mesma atenção não é direcionada à areia das praias. A areia representa um potencial vetor de contaminação e pode constituir reservatório de microrganismos patogênicos. O objetivo deste estudo foi avaliar a qualidade microbiológica da areia das praias de Santos, São Paulo. Utilizou-se a técnica das membranas filtrantes para os grupos de coliformes fecais (Escherichia coli ) e enterococos. As amostras foram coletadas em sete pontos das praias de Santos. Os ensaios foram realizados mensalmente durante 8 meses e os resultados, expressos em unidades formadoras de colônias (UFC) de bactérias por 100 g de areia, variaram de 40.000 a 2.700.000 para E. coli e de não detectado a 95.000 para enterococos, encontrando-se acima dos valores orientadores existentes em âmbito nacional (3.800 UFC.100g-1 - Rio de Janeiro) e internacional (100.000 UFC.100g-1 - Portugal). O contato com areia contaminada pode causar diversas doenças, comprometendo a qualidade de vida da população. Torna-se importante a realização de estudos baseados em evidências epidemiológicas de exposição e análises de risco, para se estabelecer padrões de qualidade e políticas públicas para monitoramento e gerenciamento da qualidade sanitária da areia das praias do litoral de São Paulo.

ABSTRACT: In Santos, coast of São Paulo State, the evaluation of the microbiological quality of the beach water is performed weekly by the Companhia Ambiental do Estado de São Paulo (CETESB), the environmental agency of the São Paulo state government. However, the same attention is not given to the sand of the beaches. Sand represents a potential contamination vector and may constitute a reservoir of pathogenic microorganisms. This study aimed to evaluate the microbiological quality of sands from Santos beaches throughout the quantification of bacteria colonies from the groups of fecal coliforms (Escherichia coli ) and Enterococcus, using the membrane filter technique. The analyses were executed monthly during 8 months and the results, expressed in bacteria colony forming units (CFU) per 100 grams of sand, vary from 40,000 to 2,700,000 for E. coli and from not detected to 95,000 for Enterococcus, being above the currently guideline values in national (3,800 CFU.100g-1) and international (100,000 CFU.100g-1) levels. It's important to mention that these guideline values were based on results from microbiological analyses of sands collected from beaches that are distant from large urban areas. The contact with contaminated sand may cause diseases, provoking impacts on the population's life quality. There is a need for further studies based on epidemiological evidences of exposure and risk analysis, in order to establish quality standards and public policies aimed to monitoring and managing the sanitary quality of sands from São Paulo's coast beaches.

Occurrence of pharmaceuticals and cocaine in a Brazilian coastal zone.

The present study determined environmental concentrations of pharmaceuticals, cocaine, and the main human metabolite of cocaine in seawater sampled from a subtropical coastal zone (Santos, Brazil). The Santos Bay is located in a metropolitan region and receives over 7367m(3) of wastewater per day. Five sample points under strong influence of the submarine sewage outfall were chosen. Through quantitative analysis by LC-MS/MS, 33 compounds were investigated. Seven pharmaceuticals (atenolol, acetaminophen, caffeine, losartan, valsartan, diclofenac, and ibuprofen), an illicit drug (cocaine), and its main human metabolite (benzoylecgonine) were detected at least once in seawater sampled from Santos Bay at concentrations that ranged from ng·L(-1) to µg·L(-1). In light of the possibility of bioaccumulation and harmful effects, the high concentrations of pharmaceuticals and cocaine found in this marine subtropical ecosystem are of environmental concern.

A critical comparison of different approaches to sediment-quality assessments in the Santos Estuarine System in Brazil.

This study focuses on the discussion of different lines of evidence (LoEs) applied to a sediment-quality assessment that considered the following: chemical concentrations of metals; polycyclic aromatic hydrocarbons (PAHs) in estuarine waters, sediments, and oysters (native and caged Crassostrea brasiliana); PAHs in semipermeable membrane devices (SPMDs); simultaneously extracted metals-acid volatile sulfides (SEM-AVS); benthic community assessment (the exploratory benthic index and the relative benthic index); chronic toxicity tests with the sea urchin Lytechinus variegatus; and bioaccumulation models. Significantly contaminated sediments from the Santos Estuarine System and the consequent toxicity of tested organisms were measured. Caged oysters presented bioaccumulation rates ≤2,500% of total PAH content and 200% of metal content when compared with control organisms from an uncontaminated area. SPMD results presented the same bioaccumulation pattern as caged oysters but at lower concentrations. Benthic communities presented some alterations, and there was a predominance of tolerant species in the inner part of the estuary. According to the SEM-AVS approach, metals should be assumed to be nonbioavailable, but experiments with transplanted C. brasiliana showed metal bioaccumulation, particularly in the cases of chromium, copper, mercury, and zinc. The weight-of-evidence approach was applied to compare and harmonize LoEs commonly used in sediment-quality assessments and to then classify estuary environments according to both their potential for having adverse effects on the biota and their possible ecological risks. All of the results of these approaches (except for SEM-AVS) were found to complement each other.

Safflower oil: an integrated assessment of phytochemistry, antiulcerogenic activity, and rodent and environmental toxicity

Gastric ulcers are a significant medical problem and the development of complications lead to significant mortality rates worldwide. In Brazil, Carthamus tinctorius L., Asteraceae, seeds essential oil, the safflower oil, is currently used as a thermogenic compound and as treatment for problems related to the cardiovascular system. In this study, by Raman spectroscopy, it was shown that oleic and linoleic acids are the compounds present in higher concentrations in the safflower oil. We demonstrated that safflower oil (750 mg/kg, p.o.) decrease the ulcerogenic lesions in mice after the administration of hydrochloric acid-ethanol. The gastric ulcers induced by non-steroidal anti-inflammatory drug (NSAID) in mice treated with cholinomimetics were treated with four different doses of safflower oil, of which, the dose of 187.5 mg/kg (p.o.) showed significant antiulcerogenic properties (**p < 0.01). Moreover, the safflower oil at doses of 187.5 mg/kg (i.d.) increased the pH levels, gastric volume (**p < 0.01) and gastric mucus production (***p < 0.001), and decreased the total gastric acid secretion (***p < 0.001). The acute toxicity tests showed that safflower oil (5.000 mg/kg, p.o.) had no effect on mortality or any other physiological parameter. Ecotoxicological tests performed using Daphnia similis showed an EC50 at 223.17 mg/l, and therefore safflower oil can be considered “non-toxic” based on the directive 93/67/EEC on risk assessment for new notified substances by European legislation. These results indicate that the antiulcer activity of Safflower oil may be due to cytoprotective effects, which serve as support for new scientific studies related to this pathology.

Ecological relevance of Sentinels' biomarker responses: a multi-level approach.

In response to the need for more sensitive and rapid indicators of environmental quality, sublethal effects on the lowest levels of biological organization have been investigated. The ecological relevance of these responses assumes a prevailing role to assure effectiveness as indicator of ecological status. This study aimed to investigate the linkages between biomarker responses of caged bivalves and descriptive parameters of macrobenthic community structure. For this purpose a multi-level environmental assessment of marine and estuarine zones was performed in São Paulo coast, Brazil. Multivariate analysis was applied to identify linkages between biological responses and ecological indices, as well as to characterizing the studied stations. Individuals of the marine mussel Perna perna caged along Santos Bay showed signs of oxidative stress, lysosomal membrane destabilization, histological alterations and reduced embryonic development. The estuarine oyster Crassostrea rhizophorae caged along Santos Port Channel showed alterations on biotransformation enzymes and antioxidant system, DNA damage and lysosomal membrane destabilization. The benthic community analysis showed reduced richness and diversity in the same areas of the Santos bay and estuary where biomarker responses were altered. Our results revealed that xenobiotics are inducing physiological stress, which may lead to changes of the benthic community structure and deterioration of the ecological status over time. Integrating biomarker responses and ecological indexes improved certainty that alterations found at community level could be related to xenobiotic as stressors, which was very useful to improve the discriminatory power of the environmental assessment.

Ecotoxicological assessment of fourpharmaceuticals compounds through acutetoxicity tests / Avaliação ecotoxicológica de quatro diferentes fármacosusando testes de toxicidade aguda

In this study, we evaluated acute toxicity of four different pharmaceutical compounds: 17 α-ethinylestradiol (EE2), fluoxetine,diclofenac and ibuprofen to Daphnia similis. The average values of EC50 were 1.63 mg/L to the 17α-ethinylestradiol(EE2), 4.41 mg/L to the fluoxetine, 46.0 mg/L to the diclofenac and 97.0 mg/L to the ibuprofen. The effects of these drugs,in particular those caused to aquatic biota, still unknown especially at low concentrations in a range from ng/L up to mg/L.

Este estudo avaliou a toxicidade aguda de quatro diferentes fármacos: 17 α-ethinylestradiol (EE2), fluoxetina, diclofenaco eibuprofeno à Daphnia similis. Os valores médios de CE50 foram de 1,63 mg/L para 17 α-ethinylestradiol (EE2), 4,41 mg/Lpara fluoxetina, 46,0 mg/L para diclofenaco e 97,0 mg/L para ibuprofeno. Os efeitos desses fármacos, sobretudo à biotaaquática, ainda são pouco conhecidos especialmente em baixas concentrações na ordem de ng/L a mg/L.

Biological effects of environmentally relevant concentrations of the pharmaceutical Triclosan in the marine mussel Perna perna (Linnaeus, 1758).

Triclosan (5-Chloro-2-(2,4-dichlorophenoxy) phenol) is an antibacterial compound widely employed in pharmaceuticals and personal care products. Although this emerging compound has been detected in aquatic environments, scarce information is found on the effects of Triclosan to marine organisms. The aim of this study was to evaluate the toxicity of a concentration range of Triclosan through fertilization assay (reproductive success), embryo-larval development assay (early life stage) and physiological stress (Neutral Red Retention Time assay - NRRT) (adult stage) in the marine sentinel organism Perna perna. The mean inhibition concentrations for fertilization (IC(50) = 0.490 mg L(-1)) and embryo-larval development (IC(50) = 0.135 mg L(-1)) tests were above environmental relevant concentrations (ng L(-1)) given by previous studies. Differently, significant reduction on NRRT results was found at 12 ng L(-1), demonstrating the current risk of the continuous introduction of Triclosan into aquatic environments, and the need of ecotoxicological studies oriented by the mechanism of action of the compound.

Artificial photosynthesis at soft interfaces.

The concept of artificial photosynthesis at a polarised liquid membrane is presented. It includes two photosystems, one at each interface for the hydrogen and oxygen evolution respectively. Both reactions involve proton coupled electron transfer reactions, and some ultrafast steps at the photosensitization stage.

Avaliação da qualidade ambiental do rio Itaguaré, Bertioga-SP,com base em testes de toxicidade e indicadores microbiológicos de balneabilidade / Evaluation of environmental quality of Itaguaré river, Bertioga-SP, using-toxicity tests and microbiological bathing conditions indexes / Evaluación de la calidad ambiental del río Itaguaré, Bertioga-SP, usar pruebasde toxicidad y índices de baño microbiológicos de las condiciones

De acordo com as Resoluções CONAMA n. 274/2000 e n. 357/2005, indicadores de balneabilidade e toxicidade devem ser avaliados em um corpo receptor aquático com objetivo de prever e evitar efeitos adversos à saúde humana e à biota aquática. O presente trabalho avaliou a qualidade das águas do rio Itaguaré (Bertioga-SP) em cinco pontos distintos, os quais se diferenciam quanto à ocupação de suas margens. Para tal, foram realizados ensaios ecotoxicológicos, mensuração da concentração de coliformes termotolerantes e parâmetros físico-químicos. Foram realizados ensaios de toxicidade aguda conforme ABNT 12713 (2004) e crônica, conforme ABNT 13373 (2005) utilizando-se cladóceros como organismos-teste, além da mensuração de coliformes termotolerantes por meio da técnica de tubos múltiplos conforme APHA (2005), para detecção e quantificação de poluição fecal por animais homeotérmicos. Os resultados indicaram toxicidade aguda no Rio Itaguaré apenas no outono nos pontos 1, 2 e 3, enquanto que a toxicidade crônica foi observada em todas as estações nos pontos 1 e 2; e, em todos os pontos (1, 2, 3, 4 e 5) na primavera e outono. Os níveis de coliformes termotolerantes demonstraram baixas concentrações que permitiram a classificação quanto à balneabilidade como excelente ou muito boa conforme CONAMA n. 274/2000. No entanto, houve maiores concentrações de coliformes nos pontos 1 e 2 durante todos os meses onde também se observou toxicidade. Esses resultados sugerem a presença de efluentes domésticos causando alterações significativas na qualidade da água nesses pontos 1 e 2, localizados próximos à Rodovia Manoel Hypólito do Rego.

According to Resolutions CONAMA N. 274/2000and N. 357/2005, bathing conditions and toxicity must be evaluated in an aquatic receiving body to foresee and prevent adverse effects to human health and aquatic biota. The present work evaluated the quality of waters of Itaguaré River (Bertioga - São Paulo) in five different points which differ as regards the occupation of its edges. For doing this, we applied eco-toxicological tests, measured the concentration of thermotolerant coliformis and physical-chemical parameters. We did tests of acute toxicity following ABNT 12713 (2004) and chronic toxicity following ABNT 13373 (2005) using cladocera as test-organisms, in addition to measuring thermotolerant coliformis through the technique of multiple pipes (APHA 2005), for detecting and quantificating fecal pollution by homeothermic animals. Results showed acute toxicity in Itaguaré River only in the autumn in points 1, 2 and 3, whereas chronic toxicity was observed in all seasons in points 1 and 2; and, in all the points (1, 2, 3, 4 and 5) in the spring and autumn. The levels of thermotolerant coliformis had low concentrations classified, as regards bathing conditions as excellent or very good cf. CONAMA N. 274/2000. However, there were greater concentrations of coliformis in points 1 and 2 during all months, and toxicity was also observed. These results suggest the presence of domestic effluent causing significant alterations in water quality in points 1 and 2, located next to Manoel Hypólito do Rego Highway.

Según las resoluciones CONAMA N. 274/2000 e N. 357/2005, se debe evaluar las condiciones del baño y la toxicidad en un cuerpo de recepción acuático para prever y prevenir efectos nocivos a la salud humana y a la biota acuática. Este trabajo evaluó la calidad de aguas del río Itaguaré (Bertioga - São Pablo) en cinco puntos distintos que se diferencian en lo que concierne a la ocupación de sus bordes. Como para hacerlo, hicimos pruebas eco-toxicológicas, medidas de la concentración de coliformis termotolerantes y parámetros fisicoquímicos. Hicimos pruebas de la toxicidad aguda según ABNT 12713 (2004) y de la toxicidad crónica según ABNT 13373 (2005) usando cladocera como organismos de prueba, además de medir coliformis termotolerantes con la técnica de las pipas múltiples (APHA 2005), para detectar y cuantificar la contaminación fecal por los animales homeotérmicos. Los resultados demostraron toxicidad aguda en el río Itaguaré solamente en el otoño en los puntos 1, 2 y 3, mientras que la toxicidad crónica fue observada en todas las estaciones en los puntos 1 y 2; y, en todos los puntos (1, 2, 3, 4 y 5) en la primavera y el otoño. Los niveles de coliformis termotolerantes tenían concentraciones bajas; en lo que concierne las condiciones de baño han sido excelentes o muy buenos según CONAMA N. 274/2000. Sin embargo, hubo mayores concentraciones de coliformis en los puntos 1 y 2 durante todos los meses, y la toxicidad también fue observada ahí. Estos resultados sugieren la presencia de efluentes domésticos que causa alteraciones significativas en calidad del agua en los puntos 1 y 2, localizados al lado de la autopista Manoel Hypólito hacen la carretera de Rego.

De los miasmas y efluvios al descubrimiento de las bacterias patógenas. Los primeros cincuenta años del Consejo Superior de Salubridad / From the miasmas and the emanations to the discovery of the pathogenic bacterias. The first fifty years of the Consejo Superior de Salubridad

Investigación que muestra la historia de la salubridad pública, las enfermedades contagiosas y el ejercicio de la medicina en la ciudad de México, de acuerdo al Consejo Superior de Salubridad. Dicho documento comprende desde la creación del Consejo hasta finales del siglo XIX, a partir de los siguientes capítulos: I. Prólogo II. Agradecimientos y una aclaración sobre las referencias III. Presentación IV. Centralismo y federalismo V. Segundo Imperio VI. La República restaurada(AU)

Evaluacion de un sistema de riego para una finca en Tarija

Contenido:Cap.I. Introduccion, Cap.II. Caracteristicas generales del área de estudio. Cap.III. Estudio agrologico de la zona. Cap.IV. Análisis hidrológico aplicado al riego. Cap.V. Demanda de riego. Cap.VI. Oferta de agua. Cap. VII. Optimizacion de sistema de riego. Cap.VIII. Diseño hidraulico del sistema de riego. Cap.IX. Costos de infraestructura. Cap.X. Conclusiones y recomendaciones. Cuadros, mapas, figuras, tablas y anexos.