1,720,979 research outputs found
Messa a punto e validazione di metodi analitici aspecifici online impieganti strumentazione a Trasformata di Fourier per la determinazione di macro e microanaliti in latte ovino
Full text linkSheep milk (SM) is, apart from bovine milk, the most important dairy food worldwide. Sardinia, Italy, is one of the most significant producer, accounting for up to 20% of the global total. Despite this, only little attention has been paid to the assessment of rapid, low-cost and reliable analytical methods devoted to measure minor components in SM. Because of the known effects of fatty acids (FA) on human health, the development of a quick, inexpensive, and accurate method to directly quantify the FA profile in SM may be a valuable tool to improve the payment system in use in Sardinia. Due the fact that the mid-infrared (MIR) spectrometry method appears to be a useful method for measuring milk FA profile, the main goal of this study is to assess a MIR method capable of quantifying the FA in SM. 250 samples of SM, collected in different areas of Sardinia from 2011 to 2013, were analyzed by a validated gaschromatographic method, while their MIR spectra were recorded. The mathematical method adopted to predict the contents of FA in SM, based on partial least squares (PLS) regression combined with i) a genetic algorithm or ii) a manual selection of IR frequencies according to the nature of each FA, has allowed us to obtain a very good accuracy of prediction for each FA in SM
Impact of Soil Management on the Functional Activity of Microbial Communities associated to Cork Oak Rhizosphere
Full text linkThe microbial ecology of cork oak rhizosphere was investigated using the Biolog community level physiological profile (CLPP) that provides a unique metabolic fingerprint helpful for the characterization of complex microbial communities. Microbial populations from the rhizosphere of cork oak plants growing at three different sites within the same area were characterized using CLPP and compared. The sites were distinguished by a different soil management under the tree cover and, in general terms, by a different anthropogenic impact. The comparison of metabolic fingerprints of the different microbial populations showed the existence of a relationship between general microbial activity and functional biodiversity in the rhizosphere and the level of anthropogenic impact. Particularly the presence of grazing animals, soil tillage and fire could be identified as the main factors affecting both the general microbial activity and the structure of microbial populations from cork oak rhizospheres
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
Building of prediction models by using Mid-Infrared spectroscopy and fatty acid profile to discriminate the geographical origin of sheep milk
No full textGeographical authentication of sheep milk is an issue related to the production of cheeses labelled with a Protected Designation of Origin (PDO). To this purpose we investigated both the capability of the fatty acid composition and the capability of the Mid-InfraRed (MIR) spectra of 250 samples of sheep milk (gathered in different areas of the region Sardinia) to discriminate the samples as what regards their geographical origin. Genetic Algorithms (GA) were applied to the fatty acid profile and to the spectra to select the informative variables for developing discriminant models able to correctly classify the samples. The models were validated on unknown samples obtaining correct predictions of 96% using the selected fatty acids and of 99% using the selected MIR spectral regions. For routine control analysis, MIR spectroscopy is preferred for being a non-destructive, cheap and real-time analytical method
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
A Contribution to the study of the distribution ofMedicago-Sinorhizobiumsymbiosis in Sardinia (Italy)
Full text linkThe paper summarizes the results of aMedicago-Sinorhizobiumgermplasm survey and collection carried out in the island of Sardinia (Italy) in 1998/99 and subsequent laboratory isolation of microbial strains, soil sample analyses and determination ofMedicagospecies. According to a stratified sampling methodology, the major ecological characteristics of island's habitats were taken into account, collecting and surveying mostly in natural or semi-natural habitats (no roadside sites nor cultivated fields were sampled). Forty-six sites, widely distributed in semi-natural representative areas of Sardinia, ranging from sea level to above 1000 m asl, were sampled and 24 were surveyed to gather additional data on species distribution. Root nodules were collected from 15 species (13 annuals) out of the total 21Medicagospecies recorded in Sardinia. Isolation of root nodule bacteria accessions and identification of 29 strains were achieved. A total number of 17 species were surveyed and mapped. The present study gives a first contribution to the knowledge of the present distribution of the species of the genusMedicagoin Sardinia with special concern to the species recorded or sampled during the survey and highlights the presence ofMedicagobiodiversity hot spots
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
Prediction of fatty acid content in sheep milk by Mid-Infrared spectrometry with a selection of wavelengths by Genetic Algorithms
No full textSheep breeding is one of the most widespread activities in Sardinia (Italy), and milk produced here is of crucial economic importance for the region. In order to make the milk payment system used in Sardinia more rewarding to the quality of milk, we developed Partial Least Square regression models to predict the concentration of the major fatty acids (measured with a GC-FID reference method) from the Mid-Infrared spectra of hundreds of Sardinian sheep milk samples collected in the period 2011-2013. Genetic Algorithms were used in order to select the most informative spectral subsets and therefore reduce the complexity of the model and in many cases also reduce the prediction error. Models obtained had a good predictive ability, with errors in the range of tenths of a gram of fatty acid on Kg of milk, and an acceptable precision for an immediate introduction on sheep milk payment in Sardinia
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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