696 research outputs found

    Reinfestation Sources for Chagas Disease Vector, Triatoma infestans, Argentina

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    Reinfestation by Triatoma infestans after insecticide spraying has caused elimination efforts in the dry Chaco region to fail repeatedly. The sources and spatial extent that need to be considered to understand the reinfestation pattern and to plan a comprehensive control program were studied in 2 adjacent rural communities in northwestern Argentina from 1993 to 1997. The effects of external, residual, and primary sources on the reinfestation pattern were evaluated by using geographic information systems, satellite imagery, spatial statistics, and 5-year retrospective data for 1,881 sites. The reinfestation process depended on primary internal sources and on surrounding infested communities. In the dry Chaco, successfully reducing the risk for reinfestation in a community depends on treating all communities and isolated sites within 1,500 m of the target community. In addition, during the surveillance phase, spraying all sites within 500 m of new foci will delay reinfestation

    Unsteady Simulation of CO/H2/N2/air Turbulent Non-Premixed Flame

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    The Sandia/ETH-Zurich CO/H2/N2 non-premixed unconfined turbulent jet flame (named ‘Flame A’) is numerically simulated by solving the unsteady compressible reactive Navier– Stokes equations in a three-dimensional axisymmetric formulation, hence, in a formally twodimensional domain. The turbulent combustion closure model adopted is the Fractal Model, FM, developed as a subgrid scale model for Large Eddy Simulation. The fuel is injected from a straight circular tube and the corresponding Reynolds number is 16 700, while the air coflows. Since the thickness of the nozzle is 0.88 mm, and the injection velocity high, ?104ms?1, capturing the stabilization mechanism of the actual flame requires high spatial resolution close to the injector. Results are first obtained on a coarse grid assuming a fast-chemistry approach for hydrogen oxidation and a single step mechanism for carbon monoxide oxidation.With this approach the flame is inevitably anchored. Then, to understand the actual flame stabilization a more complex chemical mechanism, including main radical species, is adopted. Since using this chemistry and the coarse grid of previous simulation the flame blows off numerically, attention is focused on understanding the actual flame stabilization mechanism by simulating a small spatial region close to the injection with a very fine grid. Then, analysing these results, an artificial anchoring mechanism is developed to be used in simulations of the whole flame with a coarse grid. Unsteady characteristics are shown and some averaged radial profiles for temperature and species are compared with experimental data

    Long-term data prove useful to keep track of non-indigenous seaweed fate

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    The Mar Piccolo of Taranto (southern Italy, Mediterranean Sea), a site of the European LTER network, is a transitional water system, where a century-old intensive mussel farming activity has been carried out, together with an intense import-export business of bivalve mollusks. Previous studies showed that this basinisthirdforNISseaweedintroductionintheMediterraneanSea,aftertheThau LagoonandtheVeniceLagoon.Thepresentpaperdealswiththeresultsof11-year monitoring activity on non-indigenous species (NIS) of seaweeds, which was performed in the Mar Piccolo. In the studied period (2011–2021), two different time frames (i.e., 2011–2015 and 2016–2021) were considered, since they were based on a different number of sampling sites. To investigate spatial and temporal differences in the seaweed assemblage, a multivariate analysis was performed considering the NIS and the most important native species in terms of temporal occurrence. Fourteen NIS were recorded in total in the Mar Piccolo of Taranto duringthisperiod,withvariableabundancesamongsitesandyears:ninespeciesin the firsttimeperiod,andthirteenspeciesinthesecondone.Caulerpacylindracea, recorded with negligible biomass in the first period, was absent in the secondperiod samplings. Molecular analyses confirmed the taxonomy of three species (i.e., Grateloupia minima, Neopyropia koreana, and Polysiphonia morrowii), previously identified only through morphological features. The most abundant specieswasHypneacorona,whichalmostdoubleditsbiomassinthesecondtime period compared to the first one. Three species (i.e., Caulacanthus okamurae, G. minima, and P. morrowii) increased their biomass by an order of magnitude in the second time period. No significant differences were found over years. Site 1 resulted in significant differences among the sites and different seasonal pattern occurred among the investigated sites. No significant long-term changes occurred in the seaweed assemblages, suggesting the absence of strong disturbances due to the settlement of NIS

    Il Sistema Informativo Territoriale della Rete Integrata Nazionale GPS (RING)

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    Since 2004, an important technological infrastructure has been created in Italy by INGV in order to investigate active tectonics targets. A Continuous GPS network constituted by about 130 stations has been deployed all over Italy. The development and the realization of a stable GPS monumentation, the integration with other classical seismological instruments and the choice of both satellite and internet data transmission make this network one of the most innovative and reliable CGPS networks in the world. The development of the CGPS network has been accompanied by a technologically advanced development of all the aspects related to the data acquisition and the data information mining: a database and a SIT. Based on the recent techniques of Knowledge Management, the database has been developed to manage the data and the data information of all the sites of the RING network, thus allowing us to centralize information in a single common data bank and to create an unique service of access point to the data from different remote sites by internet connections. The SIT has been developed to be fully integrated with the Knowledge Management technology and it is aimed to synthesize and to display in a geographic interface the information of the RING sites. This work has been integrated with all other spatial data, such as topographic and geo-thematic maps, geological, seismological and seismo-tectonic databases. In this work, the technological aspects of the SIT of the RING network will be detailed and some examples of thematic maps will be shown

    Merging the cryptic genera radicilingua and calonitophyllum (Delesseriaceae, rhodophyta): Molecular phylogeny and taxonomic revision

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    Radicilingua Papenfuss and Calonitophyllum Aregood are two small genera of the family Delesseriaceae that consist of only three and one taxonomically accepted species, respectively. The type species of these genera, Radicilingua thy-sanorhizans from England and Calonitophyllum medium from the Americas, are morphologically very similar, with the only recognized differences being vein size and procarp development. To date, only other two species were recognized inside the genus Radicilingua: R. adriatica and R. reptans. In this study, we analysed specimens of Radicilingua collected in the Adriatic and Ionian Sea (Mediterranean), including a syntype locality of R. adriatica (Trieste, northern Adriatic Sea), alongside material from near the type locality of R. thysanorhizans (Torpoint, Cornwall, UK). The sequences of the rbcL-5P gene fragment here produced represent the first molecular data available for the genus Radicilingua. Phylogenetic reconstruction showed that the specimens from the Adriatic and Ionian Seas were genetically distinct from the Atlantic R. thysanorhizans, even if morphologically overlapping with this species. A detailed morphological descrip-tion of the Mediterranean specimens, together with an accurate literature search, suggested that they were distinct also from R. adriatica and R. reptans. For these reasons, a new species was here described to encompass the Mediterranean specimens investigated in this study: R. mediterranea Wolf, Sciuto & Sfriso. Moreover, in the rbcL-5P tree, sequences of the genera Radicilingua and Calonitophyllum grouped in a well-supported clade, distinct from the other genera of the subfamily Nitophylloideae, leading us to propose that Calonitophyllum medium should be transferred to Radicilingua

    Resultados do monitoramento integrado da colheita da soja na safra 2019/2020 no Paraná

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    Unsteady analysis of hydrogen/air mild combustion by means of Large Eddy simulation

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    Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Combustion processes are essential for power generation, since an overwhelming majority of energy-producing devices rely on the combustion of fossil or renewable fuels. Thus the development of a combustion technology able to accomplish improvement of efficiency with reduction of pollutant emissions, such as NOx, is a main concern. MILD combustion is one of the promising techniques proposed to achieve these goals. In this combustion regime the reactants are preheated above the self-ignition temperature and enough inert combustion products are entrained in the reaction region. As a result, the characteristic times of chemical kinetics and turbulent mixing are comparable and the combustion region is no longer identifiable in a flame front but extended over a wide region, so that MILD combustion is often denoted as flameless combustion. Importantly, pollutants emissions can easily reduce because of the small temperature difference between burnt and unburnt and of the lean conditions in the combustion chamber. In this work Large Eddy Simulation (LES) of a Hydrogen/Air burner operating in the MILD combustion regime is performed. Turbulent mixing controls most of the global flame properties, so computing large scale structures by means of LES is an important key to capture mixing properties. The filtered mass, momentum, energy and species equations are discretized with a 2nd order accurate central finite difference scheme over a cylindrical non-uniform grid. Unclosed terms due to subgrid-scales are modeled using a fractal model approach (FM). Radiant transfer of energy is taken into account. The predictions of temperature and pollutant formation are compared with available experimental results.vk201

    Spatial Re-Establishment Dynamics of Local Populations of Vectors of Chagas Disease

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    Chagas disease is transmitted by blood-sucking bugs (vectors) and presents a severe public health threat in the Americas. Worldwide there are approximately 10 million people infected with Chagas disease, a disease for which there is currently no effective cure. Vector suppression is the main strategy to control the spread of this disease. Unfortunately, the vectors have been resurgent in some areas. It is important to understand the dynamics of reinfestation where it occurs. Here we show how different models fitted to patch-level bug infestation data can elucidate different aspects of re-establishment dynamics. Our results demonstrated a 6-month time lag between detection of a new infestation and dispersal events, seasonality in dispersal rates and effects of previous vector infestation on subsequent vector establishment rates. In addition we provide estimates of dispersal distances and the effect of insecticide spraying on rates of vector re-establishment. While some of our results confirm previous findings, the effects of season and previous infestation on bug establishment challenge our current understanding of T. infestans ecology and highlight important gaps in our knowledge of T. infestans dispersal
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