214 research outputs found

    Effect of Waste Discharges into a Silt-laden Estuary: A Case Study of Cook Inlet, Alaska

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    Cook Inlet is not well known. Although its thirty-foot tidal range is widely appreciated, its other characteristics, such as turbulence, horizontal velocities of flow, suspended sediment loads, natural biological productivity, the effects of fresh water inflows, temperature, and wind stresses, are seldom acknowledged. The fact that the Inlet has not been used for recreation nor for significant commercial activity explains why the average person is not more aware of these characteristics. Because of the gray cast created by the suspended sediments in the summer and the ice floes in the winter, the Inlet does not have the aura of a beautiful bay or fjord. The shoreline is inhospitable for parks and development, the currents too strong for recreational activities, and, because of the high silt concentration, there is little fishing. Yet, Cook Inlet, for all its negative attributes, can in no way be considered an unlimited dumping ground for the wastes of man. It may be better suited for this purpose than many bays in North America, but it does have a finite capacity for receiving wastes without unduly disturbing natural conditions. This report was written for the interested layman by engineers and scientists who tried to present some highly technical information in such a manner that it could be understood by environmentalists, concerned citizens, students, decision makers, and lawmakers alike. In attempting to address such a diverse audience, we risked failing to be completely understood by any one group. However, all too often research results are written solely for other researchers, a practice which leads to the advancement of knowledge but not necessarily to its immediate use by practicing engineers nor to its inclusion in social, economic, and political decision-making processes. We hope this report will shorten the usual time lag between the acquisition of new information and its use. Several additional reports will be available for a limited distribution. These will be directed to technicians who wish to know the mathematical derivations, assumptions, and other scientific details used in the study. Technical papers by the individual authors, published in national and international scientific and engineering journals, are also anticipated.The work upon which this report is based was supported in part by funds (Proj. B-015-ALAS) provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964, as amended

    Plan de negocio y valuación de empresa de producción de insumos oftalmológicos

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    Este trabajo se focaliza en estudiar sistemáticamente una empresa de biotecnología en Córdoba Argentina. La empresa se encuentra actualmente inactiva pero habilitada debido a las condiciones económicas financieras y políticas del país. El objetivo que se persigue es identificar entre todas sus variables funcionales al problema que la afecta. Una vez definido el mismo se proponen dos soluciones las cuales se analizan en aptitud factibilidad y aceptabilidad y de ellas se elije una. Para poder plantear las soluciones se realiza un exhaustivo análisis de funcionamiento de la empresa y se utiliza el método de Pareto para definir cuáles son las variables más significativas que afectan la situación. Como eje principal la solución elegida consiste en conformar una SA. realizar su valuación a través del método patrimonial, presentando las composiciones de los distintos activos y pasivos y un plan de acción donde un potencial inversor observe la variación del flujo de fondos propuesto dada determinadas condiciones de contorno enumeradas y así pueda visualizar los beneficios y el tiempo de recupero del capital que la inversión puede brindarle. La metodología utilizada es del tipo exploratorio, dado que se realizó un análisis sistémico de la empresa donde se relevaron todos los datos de funcionamiento de la misma y descriptivo ya que con la información recabada se vinculan variables y se interpreta el comportamiento en conjunto de las mismas. En la solución seleccionada se anticipa el cumplimiento del criterio fundamental establecido por los propietarios de la empresa y se propone al grupo inversor interesado un plan de acción para lograr resultados positivos en todos los periodos y recuperación de capital antes del tercer periodo de los cinco establecidos.Fil: Britch, Santiago. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas

    Spatio-temporal dispersion of Aedes taeniorhynchus in Florida

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    Aedes taeniorhynchus is normally associated in high numbers with salt marshes along coastal areas in North, Central and South America. It has the potential to be a critical vector of important human and animal arboviruses. St. Louis encephalitis, Everglades, and West Nile viruses have been isolated from it in Florida, and can transmit epizootic strains of Venezuelan equine encephalomyelitis, eastern equine encephalitis, and Rift Valley fever viruses in the lab. To better identify the threat from these viruses we are attempting to better understand the spatio-temporal patterns of Aedes taeniorhynchus in Florid

    Mechanism of generation of the flexural vibrations in an ultrasonic waveguide

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    This article deals with the problem of transfer of ultrasonic vibrations on flexible hub-waveguide system and is a continuation of research in this field [1-3]. The main field of application of flexible hub-waveguides-minimally invasive surgery for treatment of vascular diseases, where they are used to restore patency of blood vessels by destroying blood clots and tromboèmbolov. Thanks to the possibility of elastic deformation of flexible hub-waveguides, they can be delivered through a catheter system to the most remote places of the blood vessels, producing ultrasonic processing of affected sites with minimal surgical intervention. It should be borne in mind that during the work of the PA system can change its own hub-frequency waveguides and frequency generator, and this can lead to beating frequencies, formation of flexural vibrations of a working part, etc. This article therefore tasked to define the conditions of formation of low-frequency oscillations of a bend when passing ultrasonic vibrations of flexible waveguide system

    Particulate matter concentrations originating from industrial and urban sources: Validation of atmospheric dispersion modeling results

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    This study presents the analysis of the emission, transport, dispersion, and concentration of particulate matter emitted from a large industrial complex dedicated to the manufacture of cement in the town of Malagueño, province of Córdoba (Argentina), using the USEPA's (Environmental Protection Agency) AERMOD model. The model was applied for 224 industrial and background emission sources (8 stacks, 3 limestone quarries, 13 material storage piles, 18 agricultural fields and 182 paved and unpaved segment roads). The application of the model was validated with Total Suspended Particulate matter (TSP) measured at two monitoring sites, where samples were collected for 62 consecutive days in winter. The maximum TSP values obtained at both monitoring sites (748 and 1100 μg m−3) were well above the suggested WHO guidelines. The results obtained showed the impact of this industrial activity on local particulate matter concentrations, from which unpaved industrial roads and stockpiles were the most influential emission sources, directly affecting two of the closest neighborhoods in the area. Future studies will include the accumulation of heavy metals and Polycyclic Aromatic Hydrocarbons in TSP samples, the environmental risk assessment for exposure of the Malagueño population and the source apportionment of these pollutants.Fil: Abril, Gabriela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Diez, Sebastián Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Tecnológica Nacional. Facultad Regional Córdoba; ArgentinaFil: Pignata, Maria Luisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Britch, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Córdoba; Argentin

    Mathematical Modelling of Mosquito Dispersal in a Heterogeneous Environment.

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    Mosquito dispersal is a key behavioural factor that affects the persistence and resurgence of several vector-borne diseases. Spatial heterogeneity of mosquito resources, such as hosts and breeding sites, affects mosquito dispersal behaviour and consequently affects mosquito population structures, human exposure to vectors, and the ability to control disease transmission. In this paper, we develop and simulate a discrete-space continuous-time mathematical model to investigate the impact of dispersal and heterogeneous distribution of resources on the distribution and dynamics of mosquito populations. We build an ordinary differential equation model of the mosquito life cycle and replicate it across a hexagonal grid (multi-patch system) that represents two-dimensional space. We use the model to estimate mosquito dispersal distances and to evaluate the effect of spatial repellents as a vector control strategy. We find evidence of association between heterogeneity, dispersal, spatial distribution of resources, and mosquito population dynamics. Random distribution of repellents reduces the distance moved by mosquitoes, offering a promising strategy for disease control

    Remote Sensing Contributions to Prediction and Risk Assessment of Natural Disasters Caused by Large Scale Rift Valley Fever Outbreaks

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    Remotely sensed vegetation measurements for the last 30 years combined with other climate data sets such as rainfall and sea surface temperatures have come to play an important role in the study of the ecology of arthropod-borne diseases. We show that epidemics and epizootics of previously unpredictable Rift Valley fever are directly influenced by large scale flooding associated with the El Ni o/Southern Oscillation. This flooding affects the ecology of disease transmitting arthropod vectors through vegetation development and other bioclimatic factors. This information is now utilized to monitor, model, and map areas of potential Rift Valley fever outbreaks and is used as an early warning system for risk reduction of outbreaks to human and animal health, trade, and associated economic impacts. The continuation of such satellite measurements is critical to anticipating, preventing, and managing disease epidemics and epizootics and other climate-related disasters

    Biologically Informed Individual-Based Network Model for Rift Valley Fever in the US and Evaluation of Mitigation Strategies

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    Citation: Scoglio, C. M., Bosca, C., Riad, M. H., Sahneh, F. D., Britch, S. C., Cohnstaedt, L. W., & Linthicum, K. J. (2016). Biologically Informed Individual-Based Network Model for Rift Valley Fever in the US and Evaluation of Mitigation Strategies. Plos One, 11(9), 26. doi:10.1371/journal.pone.0162759Rift Valley fever (RVF) is a zoonotic disease endemic in sub-Saharan Africa with periodic outbreaks in human and animal populations. Mosquitoes are the primary disease vectors; however, Rift Valley fever virus (RVFV) can also spread by direct contact with infected tissues. The transmission cycle is complex, involving humans, livestock, and multiple species of mosquitoes. The epidemiology of RVFV in endemic areas is strongly affected by climatic conditions and environmental variables. In this research, we adapt and use a network-based modeling framework to simulate the transmission of RVFV among hypothetical cattle operations in Kansas, US. Our model considers geo-located livestock populations at the individual level while incorporating the role of mosquito populations and the environment at a coarse resolution. Extensive simulations show the flexibility of our modeling framework when applied to specific scenarios to quantitatively evaluate the efficacy of mosquito control and livestock movement regulations in reducing the extent and intensity of RVF outbreaks in the United States
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