Kinetics of tidal resuspension of microbiota: Testing the effects of sediment cohesiveness and bioturbation using flume experiments

Resuspension of the top few sediment layers of tidal mud flats is known to enhance planktonic biomass of microbiota (benthic diatoms and bacteria). This process is mainly controlled by tidal shear stress and cohesiveness of mud, and is also influenced by bioturbation activities. Laboratory experiments in a race track flume were performed to test the interactive effects of these factors on both the critical entrainment and resuspension kinetics of microbiota from silt-clay sediments from the Marennes-Oleron Bay, France. The marine snail Hydrobia ulvae was used to mimic surface bioturbation activities. As expected, the kinetics of microbial resuspension versus shear stress were largely controlled by the cohesiveness of silt-clay sediments. However, our results indicate that the effect of surface tracking by H. ulvae on microbial resuspension was clearly dependent on the interaction between sediment cohesiveness and shear velocity. Evidence was also found that microphytobenthos and bacteria are not simultaneously resuspended from silt-clay bioturbated sediments. This supports the theory that diatoms within the easily eroded mucus matrix behave actively and bacteria adhering to fine silt particles eroded at higher critical shear velocities behave passively.

Materiais cerâmicos do povoado calcolítico do Monte da Tumba (Torrão) : análises macro e microscópicas

Os autores procedem à análise das pastas cerâmicas de 24 amostras de número de recipientes, do povoado calcolítico do Monte da Tumba, recorrendo ao microscópio petrográfico. Esta metodologia revelou-se muito eficaz e permitiu atingir conclusões importantes nos domínios da tecnologia e da análise do site-catchement. De sublinhar a constatação de que as dimensões dos elementos não plásticos das pastas argilosas não parecem relacionar-se com as dimensões nem com a espessura das paredes dos recipientes, mas com o grau de resistência e porosidade pretendidos. Registe-se igualmente que as produções cerâmicas utilizaram matérias-primas locais, num raio de distância mínimo de 750m a partir do povoado.

Cerâmicas da necrópole da idade do bronze de Alfarrobeira (Silves) : análises macro e microscópicas

Neste trabalho estudam-se três fragmentos de recipientes cerâmicos, recolhidos no interior de duas cistas da necrópole, do Bronze do Sudoeste, de Alfarrobeira (Silves). Os trabalhos efectuados sobre tais fragmentos constaram: da observação macroscópica, na superfície de fractura; da observação em lâmina delgada, ao microscópio petrográfico. São, até ao presente, escassos os trabalhos realizados, no nosso país, sobre análises de pastas cerâmicas recorrendo ao microscópio petrográfico. Parece-nos, no entanto, que se trata de método particularmente aplicável ao estudo das cerâmicas pré-históricas. Estas, com efeito, ao contrário das cerâmicas mais recentes, em geral de pastas mais finas e depuradas, encerram grande quantidade de elementos não plásticos, frequentemente de mineralogia variada. Estão, pois, reunidas as condições para que, através do estudo petrográfico, se possam constituir agrupamentos de pastas, de acordo com a respectiva mineralogia para, numa fase ulterior, tendo presente as características petrográficas dos afloramentos geológicos da região mais ou menos adjacente, se possam definir prováveis zonas de abastecimento da respectiva matéria-prima ou outras informações a que o estudo comparado dos diferentes tipos de pastas devam conduzir. Foi tendo em consideração tais preocupações que se decidiu pela realização do presente trabalho.

A field study to describe diel, tidal and semilunar rhythms of larval release in an assemblage of tropical rocky shore crabs

Available information on the larval release rhythms of brachyurans is biased to temperate estuarine species and outcomes resulting from some sort of artificial manipulation of ovigerous females. In this study we applied field methods to describe the larval release rhythms of an assemblage of tropical rocky shore crabs. Sampling the broods of ovigerous females of Pachygrapsus transversus at two different shores indicated a spatially consistent semilunar pattern, with larval release maxima around the full and new moon. Yet, synchronism between populations varied considerably, with the pattern obtained at the site exposed to a lower wave action far more apparent. Breeding cohorts at one of the sampled shores apparently belonged to actual age groups composing the ovigerous population. The data suggest that these breeding groups release their larvae in alternate syzygy periods, responding to a lunar cycle instead of the semilunar pattern observed for the whole population. For the description of shorter-term rhythms, temporal series at hour intervals were obtained by sampling the plankton and confinement boxes where ovigerous females were held. Unexpectedly, diurnal release activity prevailed over nocturnal hatching. Yet, only grapsids living higher on the shore exhibited strong preferences over the diel cycle, with P. transversus releasing their larvae during the day and Geograpsus lividus during the night. The pea crab Dissodactylus crinitichelis, the spider crab Epialtus brasiliensis and a suite of xanthoids undertook considerable releasing activity in both periods. Apart from the commensal pea crab D. crinitichelis, all other taxa revealed tide-related rhythms of larval release, with average estimates of the time of maximum hatching always around the time of high tides; usually during the flooding and slack, rather than the ebbing tide. Data obtained for P. transversus females held in confinement boxes indicated that early larval release is mostly due to nocturnal hatching, while zoeal release in diurnal groups took place at the time of high tide. Since nocturnal high tides at the study area occurred late, sometimes close to dusk, early release would allow more time for offshore transport of larvae when the action of potential predators is reduced.

Les macro-déchets en mer

This text presents the general problem of nuisance and pollution created by macro-waste at sea. We clarify three main types of pollution: that of coasts, that of the sea bed and that of the open sea. The article leans on scientific data: report of the state of contamination of the coasts of France by macro waste (1982), results of works and oceanographic sea bed observation campaigns, evaluation of the contamination by micro-plastics floating on surface and concentrating in the big oceanic gyres. A paragraph is dedicated to the impacts on the ecosystems, an other one on the taken measures to fight against those macro-waste. The specific case of New Caledonia is not forgotten and in conclusion we underline the necessity of an education of the populations in terms of Eco responsibility, which appears to be a significant factor of regression of this type of nuisance that affects all the seas of the world

Antimicrobial resistance of heterotrophic marine bacteria isolated from seawater and sands of recreational beaches with different organic pollution levels in southeastern Brazil: evidences of resistance dissemination

Antimicrobial resistance of marine heterotrophic bacteria to different antimicrobials agents were evaluated in seawater, dry and wet sands from three marine recreational beaches with different pollution levels. In all studied beaches, the greatest frequencies of resistance were found in relation to penicillin. on Gonzaguinha, the most polluted beach, 72.3% of all isolated strains showed simple resistance, whilst 8.33% had multiple resistance. The values found on Ilha Porchat beach, were 70.8% and 6.9% for simple and multiple resistances, respectively. on GuaraA(0), the less polluted beach, only 35.3% of isolated strains had simple resistance. Multiple resistance was not observed. While samples from Gonzaguinha and Ilha Porchat beach showed isolated strains resistant to seven and six different antimicrobial agents, respectively, samples from GuaraA(0) beach were resistant only to penicillin and erytromicin. The positive correlations obtained between the degree of seawater contamination and frequency and variability of bacterial resistance indicate that polluted marine recreational waters and sands are sources of resistant bacteria contributing thus, to the dissemination of bacterial resistance.

Antimicrobial resistance and species composition of Enterococcus spp. isolated from waters and sands of marine recreational beaches in Southeastern Brazil

Density, species composition and antimicrobial resistance in bacteria of the Enterococcus genus were evaluated in seawater and sands from 2 marine recreational beaches with different levels of pollution. The 2 beaches showed predominance of Enterococcus faecalis and Enterococcus faecium, in the water and the sand. Dry sand presented higher densities of Enterococcus sp. and higher frequency of resistant strains than wet sand and seawater. The beach with a higher degree of pollution presented higher percentages of resistant strains (66.7% and 61.5%, in sand and in water, respectively) and resistance to a larger number of antimicrobials compared with the less polluted beach, Ilha Porchat (35.7% and 31.25% of resistant strains in sand and water, respectively). in water samples, the highest frequencies of resistance were obtained against streptomycin (38.5%) and erythromycin (25%), whilst in sand, the highest frequencies were observed in relation to erythromycin and tetracycline (38.1% and 14.3%, respectively). These results show that water and sands from beaches with high indexes of faecal contamination of human origin may be potential sources of contamination by pathogens and contribute to the dissemination of bacterial resistance. (C) 2007 Elsevier Ltd. All rights reserved.

Modeling Flood Stage-Duration-Frequency: A Risk Assessment of Critical Infrastructure in the Tidal Potomac

The service of a critical infrastructure, such as a municipal wastewater treatment plant (MWWTP), is taken for granted until a flood or another low frequency, high consequence crisis brings its fragility to attention. The unique aspects of the MWWTP call for a method to quantify the flood stage-duration-frequency relationship. By developing a bivariate joint distribution model of flood stage and duration, this study adds a second dimension, time, into flood risk studies. A new parameter, inter-event time, is developed to further illustrate the effect of event separation on the frequency assessment. The method is tested on riverine, estuary and tidal sites in the Mid-Atlantic region. Equipment damage functions are characterized by linear and step damage models. The Expected Annual Damage (EAD) of the underground equipment is further estimated by the parametric joint distribution model, which is a function of both flood stage and duration, demonstrating the application of the bivariate model in risk assessment. Flood likelihood may alter due to climate change. A sensitivity analysis method is developed to assess future flood risk by estimating flood frequency under conditions of higher sea level and stream flow response to increased precipitation intensity. Scenarios based on steady and unsteady flow analysis are generated for current climate, future climate within this century, and future climate beyond this century, consistent with the WWTP planning horizons. The spatial extent of flood risk is visualized by inundation mapping and GIS-Assisted Risk Register (GARR). This research will help the stakeholders of the critical infrastructure be aware of the flood risk, vulnerability, and the inherent uncertainty.

The most significant deficiencies in macro and micro nutrients in adolescents living with HIV/AIDS in antiretroviral therapy

Objective: To evaluate macro and micronutrients intake of adolescents living with HIV/AIDS in use of antiretroviral therapy and compare it to the Dietary Reference Intakes. Methodology: Cross-sectional study conducted with adolescents of both genders with HIV/AIDS, assessing the dietary composition of macro and micronutrients, using the 24h dietary recall. Results: 39 adolescents, average age of 15 years, 51.3% males. The participants intake of total calories, total fiber (g/d), liposoluble vitamins (A, D, E, K), vitamin B5 (mg/d), vitamin B9 (mg/d), vitamin C (mg/d), calcium (mg/d), phosphorus (mg/d), potassium (mg/d), and magnesium (mg/d) was lower than recommended. The percentages of intake lower than recommended were 79.5% for calories, 82.1% for total fibers, 89.7% for vitamin A, 100% for vitamin D, 87.2% for vitamin E, 100% for vitamin K, 71.8% for vitamin B5, 82.1% for vitamin B9, 76.9% for vitamin C, 92.3% for calcium, 61.5% for phosphorus, 97.4% for potassium, and 76.9% for magnesium. The participants ingested more carbohydrates (g), proteins (g), vitamins B2 (mg/d), B3 (mg/d), B8 (mg/d) and sodium (g/d) than recommended, the percentages above the recommendations being 92.3% for carbohydrates, 64.1% for proteins and vitamin B2, 56.4% for vitamin B3, 82.1% for vitamin B8, and 59% for sodium. The remaining nutrients were within the amounts recommended by the DRIs. Conclusion: Food intake was inadequate as compared to the recommendations of the International Nutrition Guidelines.

Contribuição da Geodésia ao monitoramento costeiro do Litoral Setentrional do Rio Grande do Norte, área de influência da indústria petrolífera

The general objective of this thesis has been seasonal monitoring (quarterly time scale) of coastal and estuarine areas of a section of the Northern Coast of Rio Grande do Norte, Brazil, environmentally sensitive and with intense sediment erosion in the oil activities to underpin the implementation of projects for containment of erosion and mitigate the impacts of coastal dynamics. In order to achieve the general objective, the work was done systematically in three stages which consisted the specific objectives. The first stage was the implementation of geodetic reference infrastructure for carrying out the geodetic survey of the study area. This process included the implementation of RGLS (Northern Coast of the RN GPS Network), consisting of stations with geodetic coordinates and orthometric heights of precision; positioning of Benchmarks and evaluation of the gravimetric geoid available, for use in GPS altimetry of precision; and development of software for GPS altimetry of precision. The second stage was the development and improvement of methodologies for collection, processing, representation, integration and analysis of CoastLine (CL) and Digital Elevation Models (DEM) obtained by geodetic positioning techniques. As part of this stage have been made since, the choice of equipment and positioning methods to be used, depending on the required precision and structure implanted, and the definition of the LC indicator and of the geodesic references best suited, to coastal monitoring of precision. The third step was the seasonal geodesic monitoring of the study area. It was defined the execution times of the geodetic surveys by analyzing the pattern of sediment dynamics of the study area; the performing of surveys in order to calculate and locate areas and volumes of erosion and accretion (sandy and volumetric sedimentary balance) occurred on CL and on the beaches and islands surfaces throughout the year, and study of correlations between the measured variations (in area and volume) between each survey and the action of the coastal dynamic agents. The results allowed an integrated study of spatial and temporal interrelationships of the causes and consequences of intensive coastal processes operating in the area, especially to the measurement of variability of erosion, transport, balance and supply sedimentary over the annual cycle of construction and destruction of beaches. In the analysis of the results, it was possible to identify the causes and consequences of severe coastal erosion occurred on beaches exposed, to analyze the recovery of beaches and the accretion occurring in tidal inlets and estuaries. From the optics of seasonal variations in the CL, human interventions to erosion contention have been proposed with the aim of restoring the previous situation of the beaches in the process of erosion.

Evaluación de riesgos basado en Normas técnicas de control interno para las instituciones oficiales autónomas, aplicado al macro proceso de compras.

Producto de la modernización del Estado, durante los últimos años en nuestro país se ha desarrollado el interés por el denominado tema administración de riesgo, adoptando nuevas normativas en materia de control interno por parte de la Corte de Cuentas de la República orientadas a la creación de valor de las instituciones gubernamentales y la generación de imagen y confianza de la población respecto al manejo de los recursos públicos. El principal objetivo de la investigación es promover la participación interactiva de la administración de las instituciones oficiales autónomas en los procesos de evaluación de riesgos por medio de fases que describen secuencialmente la metodología de dicha herramienta destinada al fortalecimiento continuo del macro proceso de compras. En el desarrollo del estudio se evidencia que la evaluación de riesgos es una opción idónea para la mitigación de estos en las instituciones públicas y como evento subsecuente la disminución de la corrupción por medio de los procesos de adquisiciones y contrataciones. Así como, su importancia y responsabilidad en dichos actividades, sin olvidar la relevancia de los riesgos que se asumen al aceptar el desafío de crear valor agregado en las empresas públicas; advirtiendo sobre las condiciones previas para la adopción de una cultura de gestión de riesgos corporativos. La investigación se realizó a partir de una muestra de las instituciones oficiales autónomas ubicadas en el Departamento de San Salvador, utilizando el método hipotético deductivo y haciendo uso de herramientas como cuestionarios y entrevistas con los jefes de las Unidades de Adquisiciones y Contrataciones Institucionales. De acuerdo a los resultados de investigación la mayoría de instituciones autónomas no están realizando una evaluación de riesgos aplicada al macro proceso de compras de conformidad con Normas Técnicas de Control Interno Especificas (NTCIE) aprobadas por la Corte de Cuentas de la República, hecho que permitió hacer una evaluación que evidencia la importancia y necesidad de la elaboración de la presente propuesta. Finalmente se presenta una propuesta para la evaluación de riesgos que comprende de manera medular el proceso a realizar para dar cumplimiento a uno de los cinco componentes definidos en las NTCIE de las instituciones gubernamentales, clasificando esta actividad en seis fases: Situación Actual, Identificación, Análisis, Gestión, Seguimiento y Actualización de la Evaluación de Riesgos. En conclusión se logró evidenciar que la propuesta de una metodología de evaluación de riesgo ayudará a la administración de las instituciones oficiales autónomas a realizar dicho proceso, por lo que se recomienda que se hagan todos los esfuerzos necesarios para su implementación.

Analyzing Tidal Fluctuations in the Big Pine Key Freshwater Lens with Time-Lapse Resistivity

The tidal influence on the Big Pine Key saltwater/freshwater interface was analyzed using time-lapse electrical resistivity imaging and shallow well measurements. The transition zone at the saltwater/freshwater interface was measured over part of a tidal cycle along three profiles. The resistivity was converted to salinity by deriving a formation factor for the Miami Oolite. A SEAWAT model was created to attempt to recreate the field measurements and test previously established hydrogeologic parameters. The results imply that the tide only affects the groundwater within 20 to 30 m of the coast. The effect is small and caused by flooding from the high tide. The low relief of the island means this effect is very sensitive to small changes in the magnitude. The SEAWAT model proved to be insufficient in modeling this effect. The study suggests that the extent of flooding is the largest influence on the salinity of the groundwater.

GIS-integrated mathematical modeling of social phenomena at macro- and micro- levels—a multivariate geographically-weighted regression model for identifying locations vulnerable to hosting terrorist safe-houses: France as case study

Adaptability and invisibility are hallmarks of modern terrorism, and keeping pace with its dynamic nature presents a serious challenge for societies throughout the world. Innovations in computer science have incorporated applied mathematics to develop a wide array of predictive models to support the variety of approaches to counterterrorism. Predictive models are usually designed to forecast the location of attacks. Although this may protect individual structures or locations, it does not reduce the threat—it merely changes the target. While predictive models dedicated to events or social relationships receive much attention where the mathematical and social science communities intersect, models dedicated to terrorist locations such as safe-houses (rather than their targets or training sites) are rare and possibly nonexistent. At the time of this research, there were no publically available models designed to predict locations where violent extremists are likely to reside. This research uses France as a case study to present a complex systems model that incorporates multiple quantitative, qualitative and geospatial variables that differ in terms of scale, weight, and type. Though many of these variables are recognized by specialists in security studies, there remains controversy with respect to their relative importance, degree of interaction, and interdependence. Additionally, some of the variables proposed in this research are not generally recognized as drivers, yet they warrant examination based on their potential role within a complex system. This research tested multiple regression models and determined that geographically-weighted regression analysis produced the most accurate result to accommodate non-stationary coefficient behavior, demonstrating that geographic variables are critical to understanding and predicting the phenomenon of terrorism. This dissertation presents a flexible prototypical model that can be refined and applied to other regions to inform stakeholders such as policy-makers and law enforcement in their efforts to improve national security and enhance quality-of-life.

Clientelismo y poder político en los inicios del siglo XX. Tensiones, disputas e intercambios entre lo micro y lo macro : Benito Juárez y la provincia de Buenos Aires

En esta tesis, analizamos la praxis política entre 1902 y 1930 poniendo en tensión el espacio bonaerense con un microcosmos: el de la localidad del interior provincial Benito Juárez. Partimos de considerar que dicha praxis se caracterizó por una multiplicidad de actuaciones (algunas conocidas, otras novedosas) dotadas de sentido y articuladas por el clientelismo político. Nuestro estudio aborda los modos en que los actores entendieron, configuraron y practicaron la política por aquellos años. En ese sentido, el clientelismo y el imaginario social en torno a la política son dos conceptos centrales de esta investigación. La tesis se estructura en tres partes: la primera, dedicada a aspectos teórico- metodológicos, está compuesta por dos capítulos en los que realizamos un bosquejo por las principales características del período y los modos en que pueden entenderse nuestros conceptos (vinculándolos a las hipótesis); damos cuenta también allí de las fuentes empleadas y la metodología. En la segunda parte nos detenemos en el juego político bonaerense. Compuesta por tres capítulos, en ella abordamos las leyes electorales provinciales vistas en perspectiva con los preceptos de la legislación reformista (desde el último tercio del siglo XIX hasta 1930) y la contribución al imaginario epocal de la Revista Argentina de Ciencias Políticas (1910-1928) y el semanario Caras y Caretas (1898-1930). En la última parte de la tesis, consideramos la vida sociopolítica en el municipio de Benito Juárez, a partir de la trayectoria de un político preeminente: Pedro Díaz Pumará. A lo largo de dos capítulos, estudiamos el imaginario social en torno a la política local, los procesos electorales, las estrategias desarrolladas por Don Pedro así como las de quienes conformaron su base social de apoyo y de quienes resistieron a su liderazgo. Finalmente, en las conclusiones sistematizamos las consideraciones de cada capítulo considerando para ello nuestra 2hipótesis heurística y las que de ella se desprenden. Planteamos la conformación del clientelismo político en actos domésticos cotidianos, el carácter bifronte de un líder frente a los asuntos provinciales y locales, la novedosa legitimidad en torno a las urnas desde 1912, la construcción de leyes que permiten accionares ya conocidos, la heterogeneidad de las bases sociales de apoyo, las lógicas de quienes se oponen a un caudillo y las estrategias desarrolladas por los participantes de la vida política