858 research outputs found

    FORAMINIFERI ATTUALI IN SEDIMENTI INFRALITORALI E CIRCALITORALI A NORD DI MESSINA (SICILIA, ITALIA)

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    Quantitative micropaleontological analyses are carried out on eleven samples from inner neritic to outer neritic sands of the sicilian coast, north of Messina. Three groups are described: 1) fossil taxa, mainly from Pliocene sediments in the terrigenous discharges, 2) live and 3) dead specimens of recent species. The distribution of benthic specimens seems largely controlled by the amounts and the sites of terrigenous sediments deposition and by the patchiness of algal biocoenoses. Percentages of live forms are higher in the northern samples, less affected by reworked or winnowed sediments: sessile foraminifers (Glabratellidae, Discorbidae) are dominant. On the contrary, dead specimens of miliolids, elphidiids, rare rotaliids ecc. are common in the thanatocoenoses of the southern and deeper samples

    Radioactivity of Mt. Etna volcano and radionuclides transfer to groundwater

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    The paper presents the results of a radiometric survey carried out on the eastern flank of Mt. Etna over an area of approximately 120 km2. Activity concentrations of 238,234U, 232,230,228Th, 226,228Ra, from 238U and 232Th decay chains, and potassium 40K were determined using α- and γ- spectrometry techniques. All rock samples presented activity concentrations of U, Th and Ra isotopes ranging from 20 Bq kg-1 to about 90 Bq kg-1, and they showed no particular compositional variations over the investigated area. Based on their respective elemental concentrations, the isotopic ratios of different elements were studied to check the presence of radioactive equilibrium, or disequilibrium, in the decay chains. Moreover, an attempt to calculate radionuclide transfer factors from soil to water was made, and the radiological risk resulting from ingestion of these isotopes contained in drinking water was calculated. The results were compared with current regulations on the quality of drinking water

    Natural radioactivity content in groundwater of Mt. Etna's eastern flank and gamma background of surrounding rocks

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    Waters of Mt. Etna are the main source of drinking water for the local population and are also distributed in municipal supply systems to neighbouring areas. Radioactivity in underground waters and surrounding rocks from the eastern flank of Mt. Etna was investigated on the basis of 9 water and 8 rock samples from 12 localities altogether. Three samples were from water drainage galleries and six from water wells. All water intakes are used for consumption. Activity concentration of uranium isotopes234,238U, radium isotopes226,228Ra and radon222Rn were determined with the use different nuclear spectrometry techniques. The determination of uranium isotopes was carried out with the use of alpha spectrometry. The measurements of radium and radon activity concentration in water were performed with the use of a liquid scintillation technique. Additionally, rocks surrounding the intakes were examined with gamma spectrometry. All water samples showed uranium concentration above Minimum Detectable Activity (MDA), with the highest total uranium (234U +238U) activity concentration equal to 149.2±6 mBq/L. Conversely, all samples showed radium isotopes activity concentrations below MDA. Radon activity concentration was within the range from 2.91±0.36 to 21.21±1.10 Bq/L, hence these waters can be classified as low-radon waters. Gamma natural background of the rocks surrounding the water sampling sites was found on the same levels as other volcanic rocks of Italy

    Wide cross-reactivity between Anopheles gambiae and Anopheles funestus SG6 salivary proteins supports exploitation of gSG6 as a marker of human exposure to major malaria vectors in tropical Africa

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    <p>Abstract</p> <p>Background</p> <p>The <it>Anopheles gambiae </it>gSG6 is an anopheline-specific salivary protein which helps female mosquitoes to efficiently feed on blood. Besides its role in haematophagy, gSG6 is immunogenic and elicits in exposed individuals an IgG response, which may be used as indicator of exposure to the main African malaria vector <it>A. gambiae</it>. However, malaria transmission in tropical Africa is sustained by three main vectors (<it>A. gambiae</it>, <it>Anopheles arabiensis </it>and <it>Anopheles funestus</it>) and a general marker, reflecting exposure to at least these three species, would be especially valuable. The SG6 protein is highly conserved within the <it>A. gambiae </it>species complex whereas the <it>A. funestus </it>homologue, fSG6, is more divergent (80% identity with gSG6). The aim of this study was to evaluate cross-reactivity of human sera to gSG6 and fSG6.</p> <p>Methods</p> <p>The <it>A. funestus </it>SG6 protein was expressed/purified and the humoral response to gSG6, fSG6 and a combination of the two antigens was compared in a population from a malaria hyperendemic area of Burkina Faso where both vectors were present, although with a large <it>A. gambiae </it>prevalence (>75%). Sera collected at the beginning and at the end of the high transmission/rainy season, as well as during the following low transmission/dry season, were analysed.</p> <p>Results</p> <p>According to previous observations, both anti-SG6 IgG level and prevalence decreased during the low transmission/dry season and showed a typical age-dependent pattern. No significant difference in the response to the two antigens was found, although their combined use yielded in most cases higher IgG level.</p> <p>Conclusions</p> <p>Comparative analysis of gSG6 and fSG6 immunogenicity to humans suggests the occurrence of a wide cross-reactivity, even though the two proteins carry species-specific epitopes. This study supports the use of gSG6 as reliable indicator of exposure to the three main African malaria vectors, a marker which may be useful to monitor malaria transmission and evaluate vector control measures, especially in conditions of low malaria transmission and/or reduced vector density. The <it>Anopheles stephensi </it>SG6 protein also shares 80% identity with gSG6, suggesting the attractive possibility that the <it>A. gambiae </it>protein may also be useful to assess human exposure to several Asian malaria vectors.</p

    Radionuclide measurements as tool for geophysical studies on Mt. Etna Volcano (Sicily)

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    Radionuclide measurements as tool for geophysical studies on Mt. Etna Volcano (Sicily

    Humoral Response to the Anopheles gambiae Salivary Protein gSG6: A Serological Indicator of Exposure to Afrotropical Malaria Vectors

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    Salivary proteins injected by blood feeding arthropods into their hosts evoke a saliva-specific humoral response which can be useful to evaluate exposure to bites of disease vectors. However, saliva of hematophagous arthropods is a complex cocktail of bioactive factors and its use in immunoassays can be misleading because of potential cross-reactivity to other antigens. Toward the development of a serological marker of exposure to Afrotropical malaria vectors we expressed the Anopheles gambiae gSG6, a small anopheline-specific salivary protein, and we measured the anti-gSG6 IgG response in individuals from a malaria hyperendemic area of Burkina Faso, West Africa. The gSG6 protein was immunogenic and anti-gSG6 IgG levels and/or prevalence increased in exposed individuals during the malaria transmission/rainy season. Moreover, this response dropped during the intervening low transmission/dry season, suggesting it is sensitive enough to detect variation in vector density. Members of the Fulani ethnic group showed higher anti-gSG6 IgG response as compared to Mossi, a result consistent with the stronger immune reactivity reported in this group. Remarkably, anti-gSG6 IgG levels among responders were high in children and gradually declined with age. This unusual pattern, opposite to the one observed with Plasmodium antigens, is compatible with a progressive desensitization to mosquito saliva and may be linked to the continued exposure to bites of anopheline mosquitoes. Overall, the humoral anti-gSG6 IgG response appears a reliable serological indicator of exposure to bites of the main African malaria vectors (An. gambiae, Anopheles arabiensis and, possibly, Anopheles funestus) and it may be exploited for malaria epidemiological studies, development of risk maps and evaluation of anti-vector measures. In addition, the gSG6 protein may represent a powerful model system to get a deeper understanding of molecular and cellular mechanisms underlying the immune tolerance and progressive desensitization to insect salivary allergens

    HIV-1 co-receptor usage:influence on mother-to-child transmission and pediatric infection

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    Viral CCR5 usage is not a predictive marker of mother to child transmission (MTCT) of HIV-1. CXCR4-using viral variants are little represented in pregnant women, have an increased although not significant risk of transmission and can be eventually also detected in the neonates. Genetic polymorphisms are more frequently of relevance in the child than in the mother. However, specific tissues as the placenta or the intestine, which are involved in the prevalent routes of infection in MTCT, may play an important role of selective barriers

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis
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