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Analisi della ripetibilità di test inerenti alcuni tratti comportamentali dei cani destinati all’addestramento alla guida, eseguiti a varie età
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La determinazione dei radicali liberi dell’ossigeno e del potenziale antiossidante biologico: intervalli di riferimento nella specie canina
No full textLatent variable models on performance tests in guide dogs : II SEM (structural equation modeling) and path diagrams.
No full textAim: Compare two reduced models to a saturated one by Structural Equation Modeling. Data: Data on a previous study conducted by factor analysis on 11 behavioral test on 143 guide dogs reared in the National Guide Dog School of Scandicci (Firenze, Italy), were analyzed using Structural Equation Modeling on three separated models. Design: In the first model (Fig. 1; Full-model), each latent variable is influencing all observed variables. In the second model (Fig. 2; Model-2), individual latent variables are influencing only observed variable with high loadings, with exception of a variable with a minimum loadings, which is affected by both latent variables. Third model (Fig. 3; Model-3) excludes minimum loading variable from Model-2. Findings: Produced results are in linea with a previous study where: - first latent variable, L1, associated to characters of reaction to external stimuli, was identified as fearfulness/curiosity; and - second latent variable, L2, related to characters of sociability and to relationship with the handler, was identified as dominance/submissiveness. Analysis of differences shown in chi- square-fitting values of models and in others fitting indexes such as Akaike Information Criterion and Root Mean Square Error of Approximation, allows to accept hyphotesis of equivalence of models. Conclusions: Use of SEM and path diagrams results intuitive and flexible allowing a simpler interpretation of relation between variables in respect to factor analysis
Thoroughbred breeding: passive immunity transfer in the newborn foal
No full textSerum samples from eleven Thoroughbred mares were collected during the last 3 weeks of pregnancy until delivery with the purpose to evaluate immunoglobulins contents (IgG, IgG(T), IgM, IgA) and total proteins levels. In order to evaluate some possibile correlations usefull for an early prediction of immunotransfer deficiency from mare to foal, colostrum and foals serum samples were also collected at different time to analyze immunoglobulins and serum proteins fractions. IgG’s mean mare serum concentration was 1672 mg/dl at 3 weeks with a trend to decrease near foaling. Total serum proteins mean level was 6.77 g/dl at delivery and 6.04 g/dl one week later. Mare serum IgG(T) were predominant immunoglobulins class in all samples and their levels were 682 mg/dl as mean. IgGa and IgGb mean values were 310 and 300 mg/dl. IgM mean level was 44 mg/dl. Colostral IgG level at foaling was more than 8000 mg/dl (48% TP) and only 330 mg/dl 24 hours after foaling, then 138 mg/dl at 15 days and 117 mg/dl at 30. A good correlation was noted between mare serum at delivery and 24 hours colostrum IgG levels. Mare serum IgA collected one week before foaling were strictly correlated with 24h colostrum IgA. Foals serum IgG mean values were nearly 40 mg/dl in the samples collected within three hours from the first suckling until reaching 1058 mg/dl (about 20% TP) at 24 hours. IgGa and IgGb subclasses showed the same evolution. IgG(T) were significantly correlated with IgG at 24h and showed highest values at 24 hours (261 mg/dl). IgM and IgA contents also showed highest values at 24h (14 and 46 mg/dl). Foal serum á-2 globulins level significantly increased between birth, 24 hours (about 0.40 g/dl) and one week (0.70 g/dl). Foal serum total ã-globulins concentration significantly increased between 0h (0.64 g/dl), 24h (1.68 g/dl) and one week. A/G ratio decreased between 0h (1.68) and 24h (1.20), following ã-globulins concentration
Latent variable models on performance tests in guide dogs. 1. Factor analysis.
No full textThe research has been conducted on behavioural test results obtained from 143 dogs of pedigreed stock
reared in the National Guide Dog School (SNCG) of Scandicci (Firenze, Italy), consisting mostly of Labradors
and Golden Retrievers, but also including German Shepherds. All dogs have been reared under quite uniform
conditions and tested individually under similar conditions.
The results following the 11 administered subtests, [that constitute variables in our analysis], were expressed
in scores ranging from 1 to 5 and used after calculation of the rank averaged scores.
The analysis of the Pearson and partial correlations between the variables points out a clean distinction in
two groups. The first consists of variables related to characters of sociability and to relationship with the handler,
with expression of dominance/submissiveness and the second to characters of reaction to external stimuli
with expressions of fearfulness/curiosity.
Results of factor analysis led us to reject the one factor model and accept a model with two factors, in which:
1) Factor I identifies variables of the group tied to the fearfulness/curiosity; 2) Factor II identifies the variables
of the group tied to sociability and to relationship with the handler.
The two factors are correlated, indicating the presence of some non negligible, indirect effects.
One out of the eleven variables has not shown important evidence of contribution to any of the factors
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
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