Circulation flow of enteropathogenia bacteria in institutionalized children. I. An epidemiologic study

The circulation flow and maintenance of enteropathogenic bacteria were studied from May 1982 to april 1983 in a population of institutionalized children and adult staff contacts in the city of Rio de Janeiro, Brazil. Subjects were assigned to three groups; A and B, included, respectively, 105 and 46 children with diarrhea who were admitted in the institution in different periods, and group C with 82 adult contacts. Faecal cultures were positive in 35.2%, 39.1% and 19.7% of subjects of groups A, B and C, respectively. It suggests that the transmission was probably fostered by the environment because of as high as 30% of faecal contamination was found in environmental samples. Higher rate of isolation and elevated antibodies levels pointed out that Escherichia coli (EPEC) was the prevalent agent. Shigella predominated in the serological tests. These findings suggest that the institution itself may play an important role in the epidemiology and transmission of enteric infections in the community.

Water scarcity, social power and the production of an elite suburb: the political ecology of water in Matadepera, Catalonia

This article investigates the history of land and water transformations in Matadepera, a wealthy suburb of metropolitan Barcelona. Analysis is informed by theories of political ecology and methods of environmental history; although very relevant, these have received relatively little attention within ecological economics. Empirical material includes communications from the City Archives of Matadepera (1919-1979), 17 interviews with locals born between 1913 and 1958, and an exhaustive review of grey historical literature. Existing water histories of Barcelona and its outskirts portray a battle against natural water scarcity, hard won by heroic engineers and politicians acting for the good of the community. Our research in Matadepera tells a very different story. We reveal the production of a highly uneven landscape and waterscape through fierce political and power struggles. The evolution of Matadepera from a small rural village to an elite suburb was anything but spontaneous or peaceful. It was a socio-environmental project well intended by landowning elites and heavily fought by others. The struggle for the control of water went hand in hand with the land and political struggles that culminated – and were violently resolved - in the Spanish Civil War. The displacement of the economic and environmental costs of water use from few to many continues to this day and is constitutive of Matadepera’s uneven and unsustainable landscape. By unravelling the relations of power that are inscribed in the urbanization of nature (Swyngedouw, 2004), we question the perceived wisdoms of contemporary water policy debates, particularly the notion of a natural scarcity that merits a technical or economic response. We argue that the water question is fundamentally a political question of environmental justice; it is about negotiating alternative visions of the future and deciding whose visions will be produced.

Comment on "Streaming potential dependence on water-content in Fontainebleau sand" by V. Allegre, L. Jouniaux, F. Lehmann and P. Sailhac

Allegre et al. recently presented new experimental data regarding the dependence of the streaming potential coupling coefficient with the saturation of the water phase. Such experiments are important to model the self-potential response associated with the flow of water in the vadose zone and the electroseismic/seismoelectric conversions in unsaturated porous media. However, the approach used to interpret the data is questionable and the conclusions reached by Allegre et al. likely incorrect

An approximate solution method for boundary layer flow of a power law fluid over a flat plate

The work in this paper deals with the development of momentum and thermal boundary layers when a power law fluid flows over a flat plate. At the plate we impose either constant temperature, constant flux or a Newton cooling condition. The problem is analysed using similarity solutions, integral momentum and energy equations and an approximation technique which is a form of the Heat Balance Integral Method. The fluid properties are assumed to be independent of temperature, hence the momentum equation uncouples from the thermal problem. We first derive the similarity equations for the velocity and present exact solutions for the case where the power law index n = 2. The similarity solutions are used to validate the new approximation method. This new technique is then applied to the thermal boundary layer, where a similarity solution can only be obtained for the case n = 1.

Historical Profile of Water Regime in Switzerland (1870-2000).

Analyse comparée de la formation et des effets des régimes institutionnels de ressources naturelles en Suisse. Partant du constat de l'accroissement significatif et généralisé de la consommation des ressources naturelles, le projet a pour ambition d'examiner, dans le cas de la Suisse, quels sont les types de régimes institutionnels -régimes composés de l'ensemble des droits de propriété de disposition et d'usages s'appliquant aux différentes ressources naturelles, de même que des politiques publiques d'exploitation et de protection les régulant- susceptibles de prévenir des processus de surexploitation et de dégradation de ces ressources. Dans le cadre de ce projet de recherche financé par le Fonds national suisse de la recherche scientifique (FNRS), il s'agit, dans un premier temps, d'analyser les trajectoires historiques d'adaptation et de changements des régimes institutionnels des différentes ressources sur une durée d'environ un siècle (1900-2000). C'est l'objet des différents screenings. Dans un second temps et à l'aide d'études de cas, ces transformations de (ou au sein des) régimes institutionnels sont analysées sous l'angle de leurs effets sur l'état de la ressource. L'ambition finale de cette recherche est de comprendre les conditions l'émergence de "régimes intégrés" capables de prendre en compte un nombre croissant de groupes d'usagers agissant à différents niveaux (géographiques et institutionnels) et ayant des usages de plus en plus hétérogènes et concurrents de ces différentes ressources. Le champ empirique de la recherche porte plus particulièrement sur cinq ressources que sont: l'eau,l'air, le sol, le paysage et la forêt.

Extensional flow of nematic liquid crystal under electric field gradient

Systematic asymptotic methods are used to formulate a model for the extensional flow of a thin sheet of nematic liquid crystal. With no external body forces applied, the model is found to be equivalent to the so-called Trouton model for Newtonian sheets (and fi bers), albeit with a modi fied "Trouton ratio". However, with a symmetry-breaking electric field gradient applied, behavior deviates from the Newtonian case, and the sheet can undergo fi nite-time breakup if a suitable destabilizing field is applied. Some simple exact solutions are presented to illustrate the results in certain idealized limits, as well as sample numerical results to the full model equations.

Neither Private nor Public: The Effects of Communal Provision of Water on Child Health in Peru

The literature on local services has focused on the effects of privatization and, if anything, has compared the effects of private and mixed public-private systems versus public provision. However, alternative forms of provision such as cooperatives, which can be very prevalent in many developing countries, have been completely ignored. In this paper, we investigate the effects of communal water provison (Comités Vecinales and Juntas Administrativas de Servicios de Saneamiento) on child health in Peru. Using detailed survey data at the household- and child-level for the years 2006-2010, we exploit the cross-section variability to assess the differential impact of this form of provision. Despite controlling for a wide range of household and local characteristics, the municipalities served by communal organizations are more likely to have poorer health indicators, what would result in a downward bias on the absolute magnitude of the effect of cooperatives. We rely on an instrumental variable strategy to deal with this potential endogeneity problem, and use the personnel resources and the administrative urban/rural classi fication of the municipalities as instruments for the provision type. The results show a negative and signi cant effect of comunal water provision on diarrhea among under- five year old children. Keywords: water utilities, cooperatives, child health, regulation, Peru. JEL Classi fication Numbers: L33; L50; L95

Increased flow of fatty acids toward beta-oxidation in developing seeds of Arabidopsis deficient in diacylglycerol acyltransferase activity or synthesizing medium-chain-length fatty acids.

Synthesis of polyhydroxyalkanoates (PHAs) from intermediates of fatty acid beta-oxidation was used as a tool to study fatty acid degradation in developing seeds of Arabidopsis. Transgenic plants expressing a peroxisomal PHA synthase under the control of a napin promoter accumulated PHA in developing seeds to a final level of 0. 06 mg g(-1) dry weight. In plants co-expressing a plastidial acyl-acyl carrier protein thioesterase from Cuphea lanceolata and a peroxisomal PHA synthase, approximately 18-fold more PHA accumulated in developing seeds. The proportion of 3-hydroxydecanoic acid monomer in the PHA was strongly increased, indicating a large flow of capric acid toward beta-oxidation. Furthermore, expression of the peroxisomal PHA synthase in an Arabidopsis mutant deficient in the enzyme diacylglycerol acyltransferase resulted in a 10-fold increase in PHA accumulation in developing seeds. These data indicate that plants can respond to the inadequate incorporation of fatty acids into triacylglycerides by recycling the fatty acids via beta-oxidation and that a considerable flow toward beta-oxidation can occur even in a plant tissue primarily devoted to the accumulation of storage lipids.

Impact of water renewal on the residual effect of larvicides in the control of Aedes aegypti

This study was carried out to evaluate the residual effect of three larvicides under laboratory conditions for 100 days in Aedes aegypti. The larval mortality rate was measured without water renewal or with daily water renewal (80%). With temephos, there was 100% mortality in both groups until the 70th day. In the Bacillus thuringiensis israelensis (Bti)-WDG test, there was no difference during the first 20 days. With Bti-G, without water renewal, mortality was sustained above 90% for up to 35 days. The second experiment (with water renewal) reduced the mortality to below 90% after the first 20 days. When renewed water was provided, the residual effect was significantly lower for all larvicides.

Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil

This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

Sulfur speciation and stable isotope trends of water-soluble sulfates in mine tailings profiles

Sulfur speciation and the sources of water-soluble sulfate in three oxidizing sulfidic mine tailings impoundments were investigated by selective dissolution and stable isotopes. The studied tailings impoundments-Piuquenes, Cauquenes, and Salvador No. 1-formed from the exploitation of the Rio Blanco/La Andina, El Teniente, and El Salvador Chilean porphyry copper deposits, which are located in Alpine, Mediterranean, and hyperarid climates, respectively. The water-soluble sulfate may originate from dissolution of primary ore sulfates (e.g., gypsum, anhydrite, jarosite) or from oxidation of sulfide minerals exposed to aerobic conditions during mining activity. With increasing aridity and decreasing pyrite content of the tailings, the sulfur speciation in the unsaturated oxidation zones showed a trend from dominantly Fe(Ill) oxyhydroxide fixed sulfate (e.g., jarosite and schwertmannite) in Piuquenes toward increasing presence of water-soluble sulfate at Cauquenes and Salvador No. 1. In the saturated primary zones, sulfate is predominantly present in water-soluble form (mainly as anhydrite and/or gypsum). In the unsaturated zone at Piuquenes and Cauquenes,the delta(34)S(S04) values ranged from +0.5 parts per thousand to +2.0 parts per thousand and from -0.4 parts per thousand to +1.4 parts per thousand Vienna Canyon Diablo Troilite (V-CDT), respectively, indicating a major sulfate source from pyrite oxidation (delta(34)S(pyrite) -1.1 parts per thousand and -0.9 parts per thousand). In the saturated zone at Piuquenes and Cauquenes, the values ranged from -0.8%. to +0.3 parts per thousand and from +2.2 parts per thousand to +3.9 parts per thousand, respectively. At Cauquenes the 34 S enrichment in the saturated zone toward depth indicates the increasing contribution of isotopically heavy dissolved sulfate from primary anhydrite (similar to+10.9%o). At El Salvador No. 1, the delta(34)S(SO4) average value is -0.9 parts per thousand, suggesting dissolution of supergene sulfate minerals (jarosite, alunite, gypsum) with a delta(34)S similar to -0.7 parts per thousand as the most probable sulfate source. The gradual decrease Of delta(18)O(S04) values from the surface to the oxidation front in the tailings impoundments at Piuquenes (from -4.5 parts per thousand to -8.6 parts per thousand Vienna Standard Mean Ocean Water, V-SMOW) and at Cauquenes (from -1.3 parts per thousand to -3.5 parts per thousand) indicates the increasing importance of ferric iron as the main electron acceptor in the oxidation of pyrite. The different delta(18)O(SO4) values between the tailings impoundments studied here reflect the local climates.

Remediation of a marine shore tailings deposit and the importance of water-rock interaction on element cycling in the coastal aquifer

We present the study of the geochemical processes associated with the first successful remediation of a marine shore tailings deposit in a coastal desert environment (Bahia de Ite, in the Atacama Desert of Peru). The remediation approach implemented a wetland on top of the oxidized tailings. The site is characterized by a high hydrauliz gradient produced by agricultural irrigation on upstream gravel terraces that pushed river water (similar to 500 mg/L SO(4)) toward the sea and through the tailings deposit. The geochemical and isotopic (delta(2)H(water) and delta(18)O(water), delta(34)S(sulfate) , delta(18)O(sulfate)) approach applied here revealed that evaporite horizons (anhydrite and halite) in the gravel terraces are the source of increased concentrations of SO(4), Cl, and Na up to similar to 1500 mg/L in the springs at the base of the gravel terraces. Deeper groundwater interacting with underlying marine sequences increased the concentrations of SO(4), Cl, and Na up to 6000 mg/L and increased the alkalinity up to 923 mg/L CaCO(3) eq. in the coastal aquifer. These waters infiltrated into the tailings deposit at the shelf-tailings interface. Nonremediated tailings had a low-pH oxidation zone (pH 1-4) with significant accumulations of efflorescent salts (10-20 cm thick) at the surface because of upward capillary transport of metal cations in the arid climate. Remediated tailings were characterized by neutral pH and reducing conditions (pH similar to 7, Eh similar to 100 mV). As a result, most bivalent metals such as Cu, Zn, and Ni had very low concentrations (around 0.01 mg/L or below detection limit) because of reduction and sorption processes. In contrast, these reducing conditions increased the mobility of iron from two sources in this system: (1) The originally Fe(III)-rich oxidation zone, where Fe(II) was reduced during the remediation process and formed an Fe(II) plume, and (2) reductive dissolution of Fe(III) oxides present in the original shelf lithology formed an Fe-Mn plume at 10-m depth. These two Fe-rich plumes were pushed toward the shoreline where more oxidizing and higher pH conditions triggered the precipitation of Fe(HI)hydroxide coatings on silicates. These coatings acted as a filter for the arsenic, which naturally infiltrated with the river water (similar to 500 mu g/L As natural background) into the tailings deposit.