1,721,030 research outputs found
Tecniche di geostatistica per la caratterizzazione di mappe di emissione di CO da osservazioni da satellite
No full textLe emissioni di CO dovute al fenomeno di “biomass burning” sono rappresentate da mappe raster stimate a partire da osservazioni da satellite raccolte da sensori di diverso tipo montati su diverse piattaforme, utilizzando inoltre algoritmi in cui i dati di input sono combinati fra loro in diverso modo. Ciò comporta che siano disponibili diversi “prodotti” di emissione di CO, dei quali è importante delineare le caratteristiche e fra le quali risulta molto utile istituire confronti reciproci.
Nel corso degli ultimi anni, nell’ambito di un più ampio lavoro sull’analisi dei dati di emissione di CO, sono stati utilizzati diversi indicatori statistici sia per caratterizzare i singoli dataset di emissione sia per verificare quanto i diversi dataset, confrontati due a due, presentino comportamenti simili o invece forniscano risultati discordanti.
Un ulteriore approccio è stato recentemente implementato per delineare le caratteristiche della distribuzione spaziale dei valori delle mappe di emissione di CO, utilizzando tecniche di geostatistica. L’obiettivo è quello di caratterizzare in maniera sintetica la variabilità spaziale dei dataset attraverso la costruzione e modellazione di semivariogrammi empirici. L’ambito di lavoro è stato ristretto a tre prodotti satellitari (ATSR, MODIS e VGT) per i quali le emissioni di CO mensili sono disponibili in maniera differenziata per classi di landcover GLC2000. In particolare le analisi sono state svolte su due finestre geografiche sub-continentali nel continente africano, con risoluzione temporale mensile e semestrale.
Le analisi condotte hanno consentito di rilevare alcuni particolari pattern di variabilità spaziale indicativi delle differenze fra le due finestre sub-continentali e delle diversità fra i vari dataset e inoltre di evidenziare, rispetto agli indici statistici precedentemente calcolati, le componenti di informazione legati alla distribuzione della copertura vegetativa
Principi di Igiene. Volume II Epidemiologia e profilassi speciale Igiene ambientale e dell'alimentazione
No full textmanuale di igiene per studenti. Epidemiologia e profilassi speciale, igiene ambientale e dell'alimentezion
Evaluation of a new PT-INR monitoring system in patients with the antiphospholipid syndrome
No full textIntroductionPatients on anticoagulant therapy with vitamin K antagonists (VKA) need frequent INR monitoring. Reliability of point-of-care (POC) devices for measuring INR needs rigorous evaluation, particularly in patient with the antiphospholipid syndrome (APS). The aim of this study was to evaluate the accuracy of the ProTime InRhythm System (here called device) for INR measurement in patients with APS on VKA.
MethodsWe compared the device INR vs. the laboratory INR measurement for blood samples from 29 APS-positive and 31 APS-negative patients consecutively enrolled. APS was confirmed by positive serological and/or phospholipid-dependent coagulation tests. Chromogenic factor X assay was used to evaluate anticoagulation. Bland-Altman difference plot for paired INR (POC vs. laboratory) was used to evaluate agreement between the device and the laboratory. The device INR relationship with factor X chromogenic assay was evaluated by orthogonal regression analysis.
ResultsOverall, 97% of the device INR measurements were similar to laboratory INR values with an absolute difference less than 0.4 units. Correlation coefficient for the device INR vs. factor X was -0.69 (P < 0.0001, CI 95% -0.80 to -0.52).
ConclusionsThe ProTime InRhythm System is an accurate point-of-care device for measuring INR also in patients with and without APS
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Pressure-induced pH changes in aqueous solutions – On-line measurement and semi-empirical modelling approach
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Validation of an automated sensitive immunoassay for quantitation of cytokines in the sputum of cystic fibrosis patients
No full textBACKGROUND: There is little information on the reproducibility of measurement of cytokine levels in sputum obtained from cystic fibrosis (CF) patients. Our aim was to investigate whether assay of cytokine levels in CF sputum is reproducible or is hampered by proteolytic degradation. METHODS: Interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) levels were measured in native and spiked samples (fresh or after freezing for 15 and 23 days at -70 degrees C) obtained from nine CF patients using an immunometric assay with chemiluminescent substrate run on a IMMULITE analyzer. RESULTS: For both cytokines, linearity was >0.98 for dilutions up to 1:32. After storage, cytokine concentrations in native samples varied between -2.9% and -5.6% for IL-8 and between 0.4% and 3.0% for TNF-alpha. In spiked samples, concentrations increased by 5.8%-12.6% for TNF-alpha and decreased by 3.8%-14.3% for IL-8 after 15 and 23 days of storage. In samples spiked with cytokines, the mean recovery rates for IL-8 and TNF-alpha were 109.4% and 106.3%, respectively. CONCLUSIONS: Measurement of IL-8 and TNF-alpha in CF sputum is reproducible and is not hampered by freezing and thawing of samples
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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