1,720,970 research outputs found
Effect of parity, days in milk, and milk yield on detailed milk protein composition in Mediterranean water buffalo.
No full textThe effects of some nongenetic factors on milk protein fraction contents and relative proportions were estimated in 606 individual milk samples of Mediterranean water buffalo. Content of α(S1)-casein (CN), α(S2)-CN, β-CN, γ-CN, κκ-CN, glycosylated κ-CN (glyco-κ-CN), α-lactalbumin, and β-lactoglobulin was measured by reversed-phase HPLC. Relative contents of α(S1)-CN%, α(S2)-CN%, β-CN%, and κ-CN% were, respectively, 32.1, 17.1, 34.5, and 15.7%, whereas γ-CN% accounted for 0.6% of total casein content. Increasing total casein content in milk would result in a greater proportion of β-CN% at the expense of all of the other major casein fractions, especially of κ-CN%. Values of α(S2)-CN%, β-CN%, and γ-CN% tended to decrease with parity, although their variations were not significant, whereas α(S1)-CN% and glyco-κ-CN% showed the opposite trend. Contents of most protein fractions showed the typical trends observed for milk components as lactation progressed, with high contents in early lactation, a minimum in midlactation, followed by a gradual increase toward the latter part of lactation. Values of α(S1)-CN% increased during lactation, whereas α(S2)-CN% decreased. The proportion of β-CN% had its maximum value between 60 and 160 d of lactation, followed by a decrease, whereas κ-CN% had its minimum value in early lactation (<60 d) and remained relatively constant in the period of mid and late lactation. Glyco-κ-CN% and β-lactoglobulin% decreased in the first part of lactation, to reach their minimum values in midlactation, followed by an increase. Milk of top-producing buffaloes, compared with that of low-producing ones, had a significantly greater value of β-CN% and glyco-κ-CN%, and lower proportion of α(S1)-CN%. The possible effect exerted by protein genetic variants in affecting variation of milk protein fraction contents and relative proportions should be further considered to better get insight into buffalo milk protein composition
Genetic diversity in some local chicken breeds using microsatellite markers
No full textGenetic relationships among Veneto native breeds of chickens were studied on the basis of
microsatellites polymorphisms. A total of 100 DNA samples from 2 local chicken breeds (45 Robusta Lionata and
43 Robusta Maculata) and a commercial broiler line (12 Golden Comet) were analyzed using 19 microsatellite
markers. The average number of alleles per locus was 4.05 and the expected heterozigosity resulted lower for the
local breeds than the broiler line. The Robusta Lionata breed and the broiler line showed a significant deficit and
excess of heterozygotes, respectively, deviating from Hardy-Weinberg equilibrium. Nei’s standard genetic distances
corrected for bias due to sampling of individuals (Da), based on allele frequencies, were calculated among breeds.
The local breeds resulted very similar confirming the same genetic origin. The results suggested that microsatellite
markers are a useful tool for studying the genetic diversity among local chicken breeds
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
Protein composition affects variation in coagulation properties of buffalo milk.
No full textThe aim of this study was to investigate the effects exerted by the content of casein and whey protein fractions on variation of pH, rennet-coagulation time (RCT), curd-firming time (K20), and curd firmness of Mediterranean buffalo individual milk. Measures of milk protein composition and assessment of genotypes at CSN1S1 and CSN3 were obtained by reversed-phase HPLC analysis of 621 individual milk samples. Increased content of αS1-casein (CN) was associated with delayed coagulation onset and increased K20, whereas average pH, RCT, and K20 decreased when β-CN content increased. Milk with low κ-CN content exhibited low pH and RCT relative to milk with high content of κ-CN. Increased content of glycosylated κ-CN was associated with unfavorable effects on RCT. Effects of milk protein composition on curd firmness were less important than those on pH, RCT, and K20. Likely, this occurred as a consequence of the very short RCT of buffalo milk, which guaranteed a complete strengthening of the curd even in the restricted 31 min time of analysis of coagulation properties and for samples initially showing soft curds. Effects of CSN1S1-CSN3 genotypes on coagulation properties were not to be entirely ascribed to existing variation in milk protein composition associated with polymorphisms at CSN1S1 and CSN3 genes. Although the role of detailed milk protein composition in variation of cheese yield needs to be further investigated, findings of this study suggest that modification of the relative content of specific CN fractions can relevantly influence the behavior of buffalo milk during processing
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
Genetic diversity and variability in Alpine sheep breeds.
No full textThe aim of this study was to analyze, through the use of microsatellite molecular markers, the genetic diversity and variability of nine Alpine sheep breeds reared in Italy (Bergamasca, Biellese, Schwarzbraunes Bergschaf, Tiroler Bergschaf, and Schnalserschaf), Germany
(Brillenschaf and Weisses Bergschaf) and Slovenia (Bovˇska and Jezerzkˇo Solˇcavska), and one Italian crossbreed population. Allelic richness was rather high in each breed highlight-
ing a considerable genetic diversity. However, the study evidenced a significant departure from Hardy–Weinberg equilibrium in all analyzed breeds caused by a heterozygote deficiency. Such lack seems to be caused both to the presence of population substructure within breed and to a rather high level of inbreeding. The genetic differentiation among breed was rather low (F ST = 0.057) but significant. The clustering analysis performed with STRUCTURE detected the presence of eight clusters; Schwarzbraunes Bergschaf and Tiroler Bergschaf were grouped together and Biellese and Bergamasca as well, evidencing a high similarity of their genetic make up. Reynolds’ genetic distance estimates confirmed the close relationship between these pairs of breeds. Moreover, Bovˇska, Jezerzkˇo-Solˇcavska and Brillenschaf resulted rather similar as expected according to their region of origin and to their com-
mon ancestors. Molecular coancestry confirmed as well such findings, suggesting that the studied breeds had origin from different ancestral populations. Concluding, microsatellite resulted a useful tool to investigate breed variability and to characterize Alpine sheep
breeds. Obtained findings suggest the need to set up a conservation plan aiming to safeguard and increase the genetic variability of the studied breeds compromised by the high level of inbreeding. Microsatellites genotyping could help to monitor breed variability and to organize matings
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