1,720,963 research outputs found
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
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
The milk fingerprint of Sardinian dairy sheep: quality and yield of milk used for Pecorino Romano P.D.O. cheese production on population-based 5-year survey
No full textThe Pecorino Romano P.D.O. is the main sheep cheese produced in Italy and the first one among the sheep cheeses, in terms of quality and value, exported from the European Union. About half of the sheep milk produced in Italy is processed into this type of cheese by 36 dairies belonging to the Pecorino Romano Consortium. Eight million records of biweekly analyses of milk collected within a 5-year period from farms delivering their milk to the aforementioned consortium were analysed in this work. Monthly evolution curves were plotted for fat, protein, lactose, pH, NaCl, SCC, bacterial load and principal fatty acids (FAs). Due to the seasonal production systems of Sardinian sheep, monthly evolution of milk fat and protein contents and cheese yield are directly linked to the lactation curve pattern and the pastures quantity and quality. Also, the FA profile of milk is affected by grass availability and quality in both early and mid-lactation, whereas it is influenced by the energy balance of ewes in late lactation. Cheese yield equation was computed based on fat and protein contents and considering the variability among dairies in technological processes used in transforming Sarda sheep milk to Pecorino Romano P.D.O. These data could be a relevant basis to set-up future grids of milk payments based on quality standards. Moreover, they could be useful to formulate administrative policies on the dairy sector with the prospective to improve milk quality of Sardinian sheep destined to the Pecorino Romano production
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
Characterization of donkey milk and metabolite profile comparison with human milk and formula milk
No full textDonkey milk is considered a potential substitute to human milk for infants affected by cows’ milk protein allergy. With the aim to widen our knowledge on this valuable food, we explored the compositional characteristics of Sardinian donkey milk. Donkey milk showed a low lipid content and high lysozyme levels compared to human milk, and a bacterial count below the recommended threshold. Hydrophilic compounds such as amino acids, organic acids and mono and disaccharides, were analyzed by GC-MS for donkey milk, formula milk and human milk. Results of the multivariate statistical analysis indicated that the metabolite profile of donkey milk is more similar to human milk than cow milk based formulae, the latter being richer in sugars and lower in amino acids. Moreover, modifications of human milk and donkey milk metabolite profiles during lactation time were studied. An increase of protein levels was observed in donkey milk, while in human milk pyroglutamic acid and myo-inositol levels increased and decreased, respectively
Ion Mobility–Mass Spectrometry Approach for the Comparison of Sheep and Goat Milk Lipidomes
Full text linkIn this work, we report an analytical procedure to investigate the lipid compositions of sheep and goat milk. This approach is based on an ion mobility–high-resolution mass spectrometric method to facilitate the identification of complex lipid species and their regiochemistry. A common triacylglycerol profile was observed for sheep and goat milk samples, while a higher abundance of medium-chain fatty acids was observed at the sn-2 position for sheep milk. Furthermore, differences can be also observed in the levels of saturated and unsaturated fatty acids at the sn-2 position. In terms of lipid classes, goat milk showed higher levels of triacylglycerols, phosphatidylinositols and ether-linked phosphatidylethanolamines, while sheep milk showed higher levels of free fatty acids, lysophosphatidylethanolamines, lysophosphocholines and non-hydroxy fatty acid-dihydrosphingosine ceramides when compared with goat milk
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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