1,721,187 research outputs found
Policosanol, reaction time and event-related potentials
No full textThe aim of the present study was to compare the results of a 1-week, double-blind placebo-controlled trial investigating the effects of isopolicosanol and octacosanol on reactivity and related brain activity. In particular, reaction time (RT) and event-related potentials such as contingent negative variations (CNV) and P300 (P3) have been studied. Thirty sedentary healthy students were tested before and after treatment (3.6 mg/die for 7 days) with orally administered tablets of placebo (group A), isopolicosanol (B) and octacosanol (C), RT were studied according to three procedures: simple RT (SRT), go/no-go RT (GRT) and choice RT (CRT), Results show that before treatment, there were no significant differences between groups A, B and C. After treatment, the RT of group A was unchanged, while the RT of groups B and C were reduced. In group B, in the SRT test, the reduction of RT was accompanied by electrical data exhibiting increased amplitudes of CNV and shorter latencies of P3. These results show that the main effect on reactivity and event-related potentials can be ascribed to policosanol and is mainly evident in the SRT test. Copyright (C) 2000 S. Karger AG, Basel
Assessment of the Completeness of OpenStreetMap and Google Maps for the Province of Pavia (Italy)
No full textFree access web-based mapping is nowadays largely used in several areas such as navigation, location-based services or when it is necessary to obtain quickly geographical information. Some of them are based on volunteers' work, among which OpenStreetMap (OSM), while some others were design for commercial purposes, such as Google Maps (GM). Given the variety of contributors and their heterogeneity, one of the critical aspects of OSM is the homogeneity and quality level of its information; furthermore, GM is also largely consulted but presents inhomogeneity between densely populated and rural areas. The paper aims at analysing the buildings completeness of OSM and GM over the Province of Pavia, in Northern Italy: the applied method will be presented together with the results obtained at two different time frames (spring 2018 and winter 2018). Finally, a quick review about the volunteers that had effectively contributed to OSM will be presented
Reactivity and event-related potentials in attentional test: effect of training
No full textTo study the effects of training on reactivity and event-related potentials a complex attentional shifting test involving reaction time was administered (Test 1) to 2-4 healthy, young students, After five days, 12 subjects were tested with the same procedure (Test 2) without training (Untrained Subjects) while 12 repeated the test at the fifth day after four days of training (Trained Subjects). During Tests 1 and 2, event-related potentials were recorded by electroencephalogram. The task consisted of each subject responding to a stimulus of a letter appearing in the centre of a geometric figure on the screen Of a Computer monitor. In the prestimulus period black points were drawn and crowded randomly into a zone of the screen. The geometric figure and the letter were shown in the centre of the crowding. There were two letters and four geometric figures randomly combined in different ways. The subject had to press different keys of the computer keyboard when specific combinations appeared, The averaged event-related potentials were characterized by a negative wave with a close relationship to selective attention before the onset of the stimulus of a geometric figure followed by letters. After the stimulus onset, a P3 complex was recorded. Trained subjects were no different from untrained Subjects in Test 1, while in Test 2 they had a shorter reaction time, an earlier peak of the selective attention related wave and P3, and a higher amplitude for the P3 complex. These measures and the correlations between them can be considered an index of the training effects Thus, these tests could be used for evaluation of the attentional style and its modification with training
Mapping land cover types using sentinel-2 imagery: A case study
No full textThis paper presents a case study of automatic classification of the remotely sensed Sentinel-2 imagery, from the EU Copernicus program. The work involved a study site, located in the area next to the city of Pavia, Italy, including fields cultivated by three farms. The aim of this work was to evaluate the so-called supervised classification applied to satellite images and performed with Esri's ArcGIS Pro software and Machine Learning techniques. The classification performed produces a land use map that is able to discriminate between different land cover types. By applying the Support Vector Machine (SVM) algorithm, it was found that, in our case, the pixel-based method offers a better overall performance than the object-based, unless a specific class is exclusively taken into consideration. This activity represents the first step of a project that fits into the context of Precision Agriculture, a recent and rapidly developing research area, whose aim is to optimize traditional cultivation methods
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
Variations 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
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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