1,721,025 research outputs found
Statistical and methodological issues in short and medium term forecasting (relazione invitata)
No full textEffects of perinatal nutrition on lactational performance, metabolic and hormonal profiles of dairy goats and respective kids
No full textThe aim of the present work was to monitor the effect of a high versus a low diet on the
metabolic and hormonal profiles of dairy goats and the progeny. Starting from the last
month of pregnancy, 14 goats were randomly allocated to two groups: Low Diet (LD) and
High Diet (HD) that received a diet that covered 80% and 140% of their energy requirements,
respectively. Blood samples were taken fromall goats, at −4, −3, −2, −1, 0 (partum), +1, +2,
+3, +4, and +5weeks fromdelivery. Blood sampleswere collected from goat kids on the day
of birth prior to colostrum feeding (week 0) and then at 1, 2, 3, 4 and 5 weeks of age. Blood
samples were assayed for their content of: urea, triglycerides, cholesterol, total protein,
albumin, calcium and inorganic phosphorus, globulin, non-esterified fatty acids (NEFA),
beta-hydroxy butyric acid (BHBA), insulin, free triiodothyronine (fT3), free thyroxine (fT4),
leptin and prolactin (PRL). Kids’ live weights (LW) and growth rate were not affected by
maternal nutrition. Milk yield was significantly (P < 0.05) higher in the HD goats. A signifi-
cant (P < 0.001) effect of time was noted on plasma glucose, total protein, albumin, globulin
and phosphorus concentrations. Concentration of plasma NEFA,BHBA, triglycerides and calcium
were significantly (P < 0.01, P < 0.05, P < 0.001 and P < 0.05, respectively) higher in the
LD goats than those in HD goats. Plasma insulin and PRL levels were higher in the HD goats
than those in LD goats (P < 0.05 and P < 0.01, respectively). Plasma leptin level were lower
on the day of partum (P < 0.05). Plasma glucose and insulin concentrations were higher in
the HD kids than those in LD kids (P < 0.01) while plasma NEFA and triglycerides concentrationswere
higher (P < 0.05) in the LD kids than in the HD kids. Plasma leptin concentrations
increased (P < 0.001) soon after kids began suckling but its values were not influenced by
the dietary treatments. The thyroid hormones increased over time and their values were
significantly higher in HD kids than those in LD kids at week 5. Our results showed that
perinatal nutrition affects goats’ and kids’ metabolic and hormonal profiles; however this
did not have an effect on foetal and kids’ growth. Nutrient restriction during pregnancy
shifted nutrient partitioning towards the uterus to sustain foetal growth. This homeorhetic
adaptation was continued during early lactation; however, it was not sufficient to sustain
milk production
Effects of plane of nutrition on oxidative stress in goats during the peripartum period
No full textThis study aimed to monitor the effect of a high (HD; 140% of energy requirements) versus a low diet (LD;
80% energy requirements) on oxidative status in goats during the peripartum period. Blood samples were
taken from all goats at 2, 1, 0 (partum), +2 and +4 weeks from delivery. Blood samples were assayed
for their content of reactive oxygen metabolites (ROMs), thiol (SH) groups, total antioxidant capacity
(OXY) and for glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities. The observation
that ROMs levels significantly increased during the peripartum period was accompanied by a
decrease of GSH-Px activity at weeks 2 and 4 postpartum, which suggested that the goats might have
experienced some degree of oxidative stress and lipid peroxidation. Overall, changes to the nutritional
level of the diet had very little or no effect on redox homeostasis. The lack of any correlation between
the biomarkers measured indicated that each oxidative stress marker responded differently, indicating
that redox homeostasis was impaired in these dairy goats during the peripartum period
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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