1,308 research outputs found

    Ridge consistency criterion

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    SUMMARY We use a multiscale approach as a semi-automated interpreting tool of potential fields. The depth to the source and the structural index are estimated in two steps: first the depth to the source, as the intersection of the field ridges (lines built joining the extrema of the field at various altitudes) and secondly, the structural index by the scale function. We introduce a new criterion, called 'ridge consistency' in this strategy. The criterion is based on the principle that the structural index estimations on all the ridges converging towards the same source should be consistent. If these estimates are significantly different, field differentiation is used to lessen the interference effects from nearby sources or regional fields, to obtain a consistent set of estimates. In our multiscale framework, vertical differentiation is naturally joint to the low-pass filtering properties of the upward continuation, so is a stable process. Before applying our criterion, we studied carefully the errors on upward continuation caused by the finite size of the survey area. To this end, we analysed the complex magnetic synthetic case, known as Bishop model, and evaluated the best extrapolation algorithm and the optimal width of the area extension, needed to obtain accurate upward continuation. Afterwards, we applied the method to the depth estimation of the whole Bishop basement bathymetry. The result is a good reconstruction of the complex basement and of the shape properties of the source at the estimated points

    L’accesso al full text dei periodici elettronici universitari: come muoversi fra cataloghi e strumenti di ricerca avanzati

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    Partendo da una panoramica dei periodici elettronici sottoscritti o acquisiti dall’Università di Trieste, si descrive la scarsa presenza di tali risorse in SOL, causata dalla difficoltà di creare e mantenere un catalogo integrato e allo stesso tempo veramente aggiornato per le risorse digitali. Le modalità di fruizione per l’utente universitario dei periodici elettronici passano perciò attraverso canali e strumenti di ricerca diversi dalle interfacce di ricerca del catalogo (Sebina o BiblioEst). L’accesso ad un titolo elettronico può avvenire semplicemente attraverso l’apposito catalogo dei periodici elettronici. Il full text di un articolo è invece accessibile tramite il sistema di linking (link resolver), a partire dai risultati di una ricerca sulle banche dati tematiche o generaliste ma soprattutto ora dal nuovo strumento di ricerca integrata chiamato Discovery Service. L’OPAC, sempre raggiungibile dal Discovery Service, rimane comunque fondamentale per la sua funzione di verifica della consistenza complessiva del periodico. Infatti, a partire dal titolo cartaceo nell’OPAC, è sempre possibile verificare la presenza di ulteriore consistenza digitale

    L’istituzione di CARE e le prime trattative nazionali

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    L'istituzione del Gruppo di Coordinamento per l'Accesso alle Risorse Elettroniche (CARE), ad opera della Commissione Biblioteche della Conferenza dei Rettori (CRUI), costituisce senza dubbio l’evento che più di altri ha introdotto una significativa trasformazione del panorama consortile italiano degli ultimi due anni. La forte incidenza nella conduzione delle attività negoziali per l’acquisto delle risorse scientifiche delle Università e la ricaduta nei rapporti tra la CRUI, i Consorzi e gli Atenei italiani ne hanno rappresentato i tratti essenziali. Il contributo ripercorre le tappe salienti della costituzione del primo tavolo negoziale a carattere nazionale per l'acquisto e l'accesso ai pacchetti elettronici dei più importanti editori scientifici

    Improved techniques in data analysis and interpretation of potential fields: examples of application in volcanic and seismically active areas

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    Geopotential data may be interpreted by many different techniques, depending on the nature of the mathematical equations correlating specific unknown ground parameters to the measured data set. The investigation based on the study of the gravity and magnetic anomaly fields represents one of the most important geophysical approaches in the earth sciences. It has now evolved aimed both at improving of known methods and testing other new and reliable techniques. This paper outlines a general framework for several applications of recent techniques in the study of the potential methods for the earth sciences. Most of them are here described and significant case histories are shown to illustrate their reliability on active seismic and volcanic areas

    Genome-wide expression profiling of the response to short-term exposure to fluconazole in Cryptococcus neoformans serotype A

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    Fluconazole (FLC), a triazole antifungal drug, is widely used for the maintenance therapy of cryptococcal meningoencephalitis, the most common opportunistic infection in AIDS patients. In this study, we examined changes in the gene expression profile of the C. neoformans reference strain H99 (serotype A) following FLC treatment in order to investigate the adaptive cellular responses to drug stress

    The new integrated aeromagnetic map of the Phlegrean Fields volcano and surrounding areas

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    In this paper we present and analyze the new detailed aeromagnetic data set resulting from a recent survey car- ried out in the Phlegrean Fields volcanic area. The survey was aimed at gaining new insight into the vol- canological characteristics of the region north of Phlegrean Fields (Parete-Villa Literno area) where remarkable thickness of volcanic/sub-volcanic rocks were found in wells. Measurement of total magnetic field was per- formed on two different flight levels, 70 m and 400 m above the ground surface, along flight lines spaced 400 m apart. Both aeromagnetic maps show the noisy effect of linear anomalies evidently due to the presence of rail- way lines. To filter out these local anomalies a method based on discrete wavelet transform was used, allowing an accurate local filtering and leaving the rest of the field practically unchanged. The filtered data set was inte- grated with the existing Agip aeromagnetic map of the Phlegrean Fields, leading to a new aeromagnetic map of the whole Phlegrean volcanic area. The compilation of the pole reduced map and of the maps of the Analytic Signal and of the Horizontal Derivative of the integrated data set represents a first step for the interpretation of the maps in terms of geological structures of the whole Phlegrean volcanic district

    Aeromagnetic survey of the Somma-Vesuvius volcanic area

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    In this paper we present and discuss the results of a geophysical airborne survey carried out in the Somma-Vesuvius volcanic area, Southern Italy, in 1999. The helicopter-borne survey was aimed at giving new detailed insights into the distribution of the magnetization of the area and, therefore, into the volcanological characteristics of the region, enhancing the knowledge given by a previous low resolution survey carried out at a regional scale by Agip. The new survey was carried out by flying on a surface parallel to the topography of the area, along flight lines spaced 600 m apart. The obtained total field map is dominated by a large anomaly related to the Mt. Somma-Vesuvius complex itself and characterized by a roughly elliptical shape. High-frequency anomalies occur in the edifice and in the area east of it, partly produced by cultural noise due to the densely inhabited area. The compilation of the maps of the analytic signal and of the horizontal derivative of the field allowed the location of the lateral boundaries of the magnetic sources of the area and represents a first step toward the interpretation of the maps in terms of geological structures

    In vitro study of uptake and synthesis of creatine and its precursors by cerebellar granule cells and astrocytes suggests some hypotheses on the physiopathology of the inherited disorders of creatine metabolism

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    <p>Abstract</p> <p>Background</p> <p>The discovery of the inherited disorders of creatine (Cr) synthesis and transport in the last few years disclosed the importance of blood Cr supply for the normal functioning of the brain. These putatively rare diseases share a common pathogenetic mechanism (the depletion of brain Cr) and similar phenotypes characterized by mental retardation, language disturbances, seizures and movement disorders. In the effort to improve our knowledge on the mechanisms regulating Cr pool inside the nervous tissue, Cr transport and synthesis and related gene transcripts were explored in primary cultures of rat cerebellar granule cells and astrocytes.</p> <p>Methods</p> <p>Cr uptake and synthesis were explored in vitro by incubating monotypic primary cultures of rat type I astrocytes and cerebellar granule cells with: a) D<sub>3</sub>-Creatine (D<sub>3</sub>Cr) and D3Cr plus β-guanidinopropionate (GPA, an inhibitor of Cr transporter), and b) labelled precursors of Guanidinoacetate (GAA) and Cr (Arginine, Arg; Glycine, Gly). Intracellular D3Cr and labelled GAA and Cr were assessed by ESI-MS/MS. Creatine transporter (<it>CT1</it>), L-arginine:glycine amidinotransferase (<it>AGAT</it>), and S-adenosylmethionine:guanidinoacetate N-methyltransferase (<it>GAMT</it>) gene expression was assessed in the same cells by real time PCR.</p> <p>Results</p> <p>D3Cr signal was extremely high in cells incubated with this isotope (labelled/unlabelled Cr ratio reached about 10 and 122, respectively in cerebellar granule cells and astrocytes) and was reduced by GPA. Labelled Arg and Gly were taken up by the cells and incorporated in GAA, whose concentration paralleled that of these precursors both in the extracellular medium and inside the cells (astrocytes). In contrast, the increase of labelled Cr was relatively much more limited since labelled Cr after precursors' supplementation did not exceed 2,7% (cerebellar granule cells) and 21% (astrocytes) of unlabelled Cr. Finally, <it>AGAT, GAMT </it>and <it>SLC6A8 </it>were expressed in both kind of cells.</p> <p>Conclusions</p> <p>Our results confirm that both neurons and astrocytes have the capability to synthesize and uptake Cr, and suggest that at least in vitro intracellular Cr can increase to a much greater extent through uptake than through <it>de novo </it>synthesis. Our results are compatible with the clinical observations that when the Cr transporter is defective, intracellular Cr is absent despite the brain should be able to synthesize it. Further research is needed to fully understand to what extent our results reflect the in vivo situation.</p

    Structural integrity of Ellisolandia elongata reef:a mechanical approach to compare tensile strengths in natural and controlled environments

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    INTRODUCTION:We aimed to evaluate the site of placentation on the pregnancy outcomes of patients with placenta previa. METHODS:This retrospective study included 678 cases of placenta previa. Basic information and pregnancy outcome data were collected. Differences between the different placenta previa positions and pregnancy outcomes were compared using the chi-square and independent t tests. Logistic and multiple regression analyses were used to calculate the odds ratios (ORs) to determine the risk factors for PAS disorders and postpartum hemorrhage and evaluate the effect of placental attachment site on pregnancy outcomes. RESULTS:There was no significant difference between the PAS disorders rate and the incidence of complete placenta previa depending on the type of placentation; however, placental attachment site influenced the pregnancy outcome. Placental attachment to the anterior wall was associated with shorter gestational age, low birth weight, lower Apgar score, higher prenatal bleeding rate, increased postpartum hemorrhage, longer duration of hospitalization, and higher blood transfusion and hysterectomy rates compared to cases with lateral/posterior wall placenta. Placental attachment at the incision site of a previous cesarean section significantly increased the incidence of complete placenta previa and PAS disorders compared with placental attachment at a site without incision, but did not significantly influence pregnancy outcomes. Placental attachment to the anterior wall was an independent risk factor for postpartum hemorrhage in patients with placenta previa. Placental attachment to a previous incision site was an independent risk factor for PAS disorders. CONCLUSION:The site of placental attachment in patients with placenta previa has an important influence on the pregnancy outcome. When the placenta is located on the anterior wall, clinicians should pay attention to the adverse pregnancy outcomes and the possibility of massive postpartum hemorrhage. In cases of placental attachment to the uterine incision site, physicians should be highly vigilant regarding the occurrence of PAS disorders
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