1,721,043 research outputs found
Groundwater nitrate contamination risk assessment: a comparison of parametric systems and simulation modelling
No full textGroundwater nitrate contamination is a source of rising concern that has been faced throughthe introduction of several regulations in different countries. However the methodologies used in thedefinition of Nitrate Vulnerable Zones are not included in the regulations. The aim of this work was tocompare different methodologies, used to asses groundwater nitrate contamination risks, based onparametric systems or simulation modelling. The work was carried out in Piedmont, Italy, in an areacharacterised by intensive animal husbandry, high N load, a shallow water table and a coarse type ofsub-soil sediments. Only N loads from agricultural non-point sources were considered. Differentmethodologies with different level of information have been compared to determine the groundwaternitrate contamination risk assessment: N load, IPNOA index, the intrinsic contamination risk fromnitrates, leached N and N concentration of the soil solution estimated by the simulation model. Thegood correlation between the IPNOA index and the intrinsic nitrate contamination risk revealed thatthe parameters that describe the soil in this area did not lead to a different classification of the parcels.The intrinsic nitrate contamination risk was greatly influenced by N fertilisation, however the effect ofthe soils increased the variability in comparison to the IPNOA index. The leached N and Nconcentration in the leaching were closely correlated. The dilution effect of percolated water wasalmost negligible. Both methodologies were slightly correlated to the N fertilisation and the twoindexes. The correlations related to the intrinsic nitrate contamination risk was higher than thoserelated to IPNOA, and this means that the effect of taking into account soil parameters increases thecorrelation to the prediction of the simulation mode
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
In vitro platelet aggregation defects in patients with myeloproliferative disorders and high platelet counts: are they laboratory artefacts?
No full textAbstract
It has been recently shown that in vitro platelet aggregation is inhibited when platelet concentration in platelet-rich plasma (PRP) is "normalized" by the addition of platelet-poor plasma (PPP). In this study we tested the hypothesis that the large amount of PPP required to "normalize" PRP in patients with thrombocytosis may result in falsely defective platelet function. To this end, we evaluated platelet aggregation in PRP samples "normalized" with either PPP or buffer in 16 patients with high platelet counts induced by myeloproliferative disorders. Comparison with the results obtained in healthy subjects demonstrated that patients had reduced platelet responses to ADP or collagen in PRP/PPP samples, but normal responses in PRP/buffer. By contrast, the majority of patients had severely defective platelet response to epinephrine independently from the methodological approach. We suggest that the reduced in vitro platelet aggregation previously described in patients with myeloproliferative disorders and thrombocytosis partially derived from a laboratory artefact
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
Strontium-Doped Hematite as a Possible Humidity Sensing Material for Soil Water Content Determination
Full text linkThe aim of this work is to study the sensing behavior of Sr-doped hematite for soil water content measurement. The material was prepared by solid state reaction from commercial hematite and strontium carbonate heat treated at 900 °C. X-Ray diffraction, scanning electron microscopy and mercury intrusion porosimetry were used for microstructural characterization of the synthesized powder. Sensors were then prepared by uniaxially pressing and by screen-printing, on an alumina substrate, the prepared powder and subsequent firing in the 800–1,000 °C range. These sensors were first tested in a laboratory apparatus under humid air and then in an homogenized soil and finally in field. The results evidenced that the screen printed film was able to give a response for a soil matric potential from about 570 kPa, that is to say well below the wilting point in the used soil
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
Capitolo 8: Interventi sulle caratteristiche del suolo: Lavorazioni
No full textIl capitolo descrive le tecniche di lavorazione del terreno agrario, ne discute le caratteristiche positive e negative, con un particolare approfondimento alle esigenze di tutela della qualità del suolo, intesa nei vari aspetti: fisici, chimici, biologici ed ambientali. Il testo, di carattere didattico è rivolto in particolare agli studenti universitari della laurea di Scienze e Tecnologie Agrarie. L'intera monografia, infatti, realizzata da un pool di professori universitari italiani, è stata promossa dalla Società Italiana di Agronomia come strumento principale per le lauree triennali del settore AGR/02
- …
