1,720,973 research outputs found
PCV2 isolate variation: Its role in pathogenicity and disease control
No full textCharreyre, C.; Joisel, F.. (2007). PCV2 isolate variation: Its role in pathogenicity and disease control. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/141303
Effectiveness of sow vaccination with CIRCOVAC® (Merial) in a PCV2-positive but PCVD-free herd under Italian conditions
No full textThe objective of this study was to assess the efficacy of CIRCOVAC sow vaccination, in reducing mortality and improving growth of the offspring, in a PCV2 positive, PMWS negative herd (absence of PCVD), under Italian conditions.
Sow vaccination with CIRCOVAC, induced a significant improvement in overall piglet mortality rate and an increase of the ADWG was seen from 68 days to slaughter, confirming other works
Vaccination with an innovative pressure-adjustable needle-free injection device
No full textThe Valery® is an innovative pressure-adjustable needle-free injection device (NFID). The objective of this study was to determine appropriate operation of this NFID for vaccination by evaluating the location of a vaccine in pigs after application. In a first trial, 4 groups of 12 pigs weighing respectively 4-5 kg, 6-7 kg, 8-10 kg and 15-20 kg were injected with a dye-labeled vaccine (Circovac, Merial), 0.5 mL in the neck using the NFID. Per group 3 pressure settings of the device were tested (A:low, B:medium or C:high), 4 pigs each. The pigs were immediately euthanized and frozen in vertical position (48 h; -20°C). Cross-sectional slices (3 per pig, 1 cm thick) at the injection sites were collected and digitalized by photography. The slices were checked on the penetration and dispersion of the vaccine by image analysis. In a second trial, 2 groups of 4 pigs weighing respectively 6-7 kg or 8-10 kg were used. Following cleaning and drying of the skin surface, the vaccine was injected using the NFID, in the neck. Before injection a piece of blotting paper in an empty screw cap tube had been weighed. Just after injection, the piece of paper was applied on the skin surface at the injection site for 2 secs , then stored in the screw cap container. The tube was weighed. The percentage of vaccine dose on the skin surface (SkQ) was calculated by difference. The depth of penetration of the vaccine whatever the weight group or pressure settings was 2.33±0.76 cm (n=48) with no difference observed between the pressure settings (A, n. 16, 2.14±0.77; B n. 16, 2.61±0.72; C, n. 16, 2.23±0.75 cm) or the weight group (4-5Kg, n.12, 2.18±0.4; 6-7Kg, n. 12, 2.40±0.24; 8-10Kg, n. 12, 1.89±0.56; 15-20Kg, n. 12, 2.83±1.18 cm) . The percentage of the vaccine present at the muscular level was varying between 70% (pressure A, 4-5kg) to 100% (pressure C, 6-7 Kg). In the different weight groups on average 87.0%. Setting B and C had the highest amount IM, resp.92.5 and 89.2%. The area of muscular distribution is the highest with pressure C compared to A and B (p=0.04). In trial 2,the SkQ was low whatever the operating pressure (A: 3.5±2.2%; B: 2.9±1.9%; C:1.5±0.4%) and the weight groups with a significant inverse relation between operating pressure and SkQ as well as a remarkable uniformity at the highest pressure setting. Under the conditions of the study, the Valery NFID was shown to deliver a 0.5 mL vaccine recommended for IM vaccination satisfactorily. It is advised to use pressure settings medium to high. The volume of vaccine spread on the skin was considered as acceptable. Vaccination compliance was thought not to be impacted by the NFID
Comparative evaluation of two PCV2 vaccines in piglets
No full textIntroduction. At present in Europe several commercial PCV2 vaccines are available for use in piglets. One of these is also licensed for sows. Under field conditions, all PCV2 vaccines available are effective, showing decreased mortality and cull rates and significantly improving average daily weight gain (ADWG). The objective of this study was to compare the efficacy of two PCV2 vaccines.
Materials and methods. A controlled, blinded and randomized field study was performed on an Italian 420-sow farrow-to-finish farm without PCVD anamnesis. One thousand and fifty piglets, from five consecutive batches, were included in this trial. The piglets were stratified by sex, weight, parity of the sow and randomly allocated to 3 groups. At weaning, each piglet received 0.5 ml Circovac® i.m. (Group A) or 1 ml Circoflex® i.m. (Group B). The pigs in Group C were not vaccinated and kept as control animals. Control and vaccinated piglets stayed intermingled. All animals were vaccinated against M. hyopneumoniae 2 days before PCV2 vaccinations, with a one-shot W/O vaccine. The body weight was determined at 25, 110 and 225 days of age (d). All animals were monitored for clinical symptoms and mortality was recorded during the whole study period. Only batch 3 was chosen for collection of laboratory data in order to assess the impact of vaccination on viral pressure over time. Blood samples were collected monthly and serum samples of Circovac® vaccinated (n=12), Circoflex® vaccinated (n=13), as well as of control animals (n=11) were analyzed by a competitive ELISA. Pooled sera from at least 3 subjects were analyzed by quantitative PCR (qPCR). The ADWG from 25d to 105d, 105d to 220d and from 25d to 220d in the different groups were compared. The comparison was made by assessing any differences between: a) vaccinated subjects (groups A and B) to group C, b) vaccinated with Circovac® or with Circoflex® to non-vaccinated animals (group C), d) vaccinated with Circovac® to animals vaccinated with Circoflex®.
Results. In the periods 25-105d, 105-220d and 25-220d the AWDG of vaccinated subjects were significantly higher (respectively: Mann-Whitney U=97767, p<0.01; U=97477, p<0.05; U=92101, p<0.01) than those of the control animals. Both animals vaccinated with Circovac® and those vaccinated with Circoflex® showed ADWG significantly higher (p<0.05) than those of the control group during the three considered periods. The difference between ADWG of group B and group A was not statistically significant for any of the three time periods. The percentage of 25-to-220-day dead pigs and runts: 5.73%, 6.26% and 6.28% for groups A, B and C, respectively, were very similar; however, incidence of underweight pigs was statistically lower in the vaccinated groups. Antibodies titre and serum viral load were statistically lower in vaccinated subjects.
Discussion. Compared to the control group, vaccinated animals showed a significant increase of ADWG. Vaccinated animals had a lower titre of PCV2 specific antibodies and the vaccination seemed to reduce the viral pressure in the facilities. This observation is supported by the qPCR data, which showed, that vaccinated animals had a lower serum viral load. No statistically significant difference in the considered parameters was observed between the two vaccines
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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