Dictyocaulus viviparus seroprevalence and epidemiology in Costa Rican dairy cattle

A cross-sectional serological survey of Dictyocaulus viviparus was carried out to determine the prevalence of lungworm infections in 28 dairy cattle farms distributed in five selected areas from Costa Rica. The influence of area, farm, host (breed, age and lactation number) and ecological factors (altitude and life zones) on the presence of lungworm infection was analyzed. A sub-sample of 924 sera collected between September 1998 and July 1999 was processed by ELISA (Ceditest). A total of 162 (17.5%) animals from 26 (93.0%) farms showed antibodies against D. viviparus. The overall seroprevalence detected among areas was Poás 25.0%, Cartago 24.3%, Tilarán 22.0%, Alfaro Ruiz 12.0% and San Carlos 12.1%. Using analysis of variance no significant influence of area and host factors on D. viviparus infections was determined, whereas the variable farm within area was highly significant (p<0.001). However, altitude and life zones showed significant association to seropositive animals, when a Chi-square test was applied. In altitudes of 1000-2000 m (p<0.001) and life zones of Lower Montane moist forest and Montane moist forest (p<0.001) D. viviparus infections in bovines were significantly higher. The results obtained in this study indicate a high D. viviparus seroprevalence in the analyzed farms and that the factors farm, altitude and life zones were significantly related to lungworm infections.     

Linking ecosystem services,urban form and green space configuration using multivariate landscape metric analysis

Context

Landscape metrics represent powerful tools for quantifying landscape structure, but uncertainties persist around their interpretation. Urban settings add unique considerations, containing habitat structures driven by the surrounding built-up environment. Understanding urban ecosystems, however, should focus on the habitats rather than the matrix.

Objectives

We coupled a multivariate approach with landscape metric analysis to overcome existing shortcomings in interpretation. We then explored relationships between landscape characteristics and modelled ecosystem service provision.

Methods

We used principal component analysis and cluster analysis to isolate the most effective measures of landscape variability and then grouped habitat patches according to their attributes, independent of the surrounding urban form. We compared results to the modelled provision of three ecosystem services. Seven classes resulting from cluster analysis were separated primarily on patch area, and secondarily by measures of shape complexity and inter-patch distance.

Results

When compared to modelled ecosystem services, larger patches up to 10 ha in size consistently stored more carbon per area and supported more pollinators, while exhibiting a greater risk of soil erosion. Smaller, isolated patches showed the opposite, and patches larger than 10 ha exhibited no additional areal benefit.

Conclusions

Multivariate landscape metric analysis offers greater confidence and consistency than analysing landscape metrics individually. Independent classification avoids the influence of the urban matrix surrounding habitats of interest, and allows patches to be grouped according to their own attributes. Such a grouping is useful as it may correlate more strongly with the characteristics of landscape structure that directly affect ecosystem function.

     

Development of a CE method to analyze organic acids in dairy products: application to study the metabolism of heat-shocked spores

Organic acids are relevant in dairy products for nutritional reasons and because they contribute to the flavor and aroma. They are the major products of carbohydrate catabolism of lactic acid bacteria and nonstarter bacteria associated with milk. In several research and quality programs, it is very important to develop a rapid and sensitive method for their quantitative determination in dairy products to monitor bacterial growth and activity. A capillary electrophoresis method for the simultaneous determination of oxalic, citric, formic, succinic, orotic, uric, pyruvic, acetic, propionic, lactic, and butyric acid in less than 18 min has been developed. Various parameters affecting analysis, including capillary length, type, composition, and pH of the electrolyte have been optimized. Some alternatives are given to improve the separation of particular organic acids of special interest. Its application to analyze the quality of some dairy products has been investigated. In addition, the suitability of the technique to determine profiles of organic acids generated during the metabolism of heat-shocked spores has been demonstrated.     

Improving postharvest resistance in fruits by external application of trans-resveratrol

As it is well-known, one of the main problems of modern agriculture is the postharvest fruit losses due to pathogen's attack and natural senescence during storage. Well established solutions to improve this situation, such as, for example, storage under controlled conditions and the use of synthetic pesticides, are not free of problems due to human health risks and environmental effects caused by chemical pesticides. A new strategy to solve these problems consists of developing methods to improve the natural plant resistance by using, upon their identification, the plant's own defense molecules, in other words, applying methods based on the plant's own natural processes of pest suppression to control spoilage. This requires the identification of components of the natural defense response in plants, which, in turn, demands highly sensitive, fast, and versatile analytical methods especially for trace, nonvolatile, compounds. In this work a laser-based technique has been applied for screening the postharvest elicitation of resveratrol by Botrytis cinerea in grapes. Besides antifungal character, resveratrol is known to present important antioxidant properties, which could also have positive effects on fruit conservation during storage. Consequently, several experiments were carried out in which exogenous application of resveratrol to several fruits maintained their postharvest quality. The quality of both resveratrol-treated and untreated fruits has been studied by the assessment of the biochemical composition and sensory analysis. Indeed, the present work demonstrates that the external application of resveratrol does not alter the sensorial and biochemical properties of the fruit.     

Effect of malondialdehyde on the determination of furosine in milk-based products

For nutritional purposes the recombination of milk or milk proteins with polyunsaturated fatty acids had long been considered in newly designed products, such as functional foods. Four milk-resembling model systems were prepared having malondialdehyde content ups to 1 mM. Systems were heated between 110 and 150 degrees C for up to 30 min. The effect of the presence of bifunctional aldehydes on the determination of furosine as a heat-induced marker was investigated. Levels of 0.01 mM MAD in the reaction mixture could affect significantly the determination of furosine in a milk-based system. Impairment of lysyl residues through the analysis of furosine could be underestimated in the presence of malondialdehyde.     

Development of an injection site sarcoma shortly after meloxicam injection in an unvaccinated cat

A single dose of a rapidly-absorbed non-steroidal anti-inflammatory drug (NSAID) was injected into the subcutaneous tissue of the interscapular region of a 12.5-year-old cat. A mild swelling was noticed at the injection site 6 weeks later. This progressed into a 5 cm diameter mass which was removed 6 months after the injection had been given. An injection site sarcoma (ISS) was diagnosed histologically. As the cat had not been vaccinated for at least 12 years, the previous NSAID injection was considered to be a possible cause of the ISS. Inflammation is thought to be important in the development of ISS. If injection of a rapidly-absorbed NSAID can stimulate sufficient inflammation to promote the development of an ISS, other non-vaccine injections may also have the potential to influence ISS development. This suggests that injection of both vaccines and non-vaccine medications should be minimised to reduce the risk of ISS development.     

Content validation using an expert panel: assessment process for assistive technology adopted by farmers with disabilities

This article reports the use of an expert panel to perform content validation of an experimental assessment process for the safety of assistive technology (AT) adopted by farmers with disabilities. The validation process was conducted by a panel of six experts experienced in the subject matter, i.e., design, use, and assessment of AT for farmers with disabilities. The exercise included an evaluation session and two focus group sessions. The evaluation session consisted of using the assessment process under consideration by the panel to evaluate a set of nine ATs fabricated by a farmer on his farm site. The expert panel also participated in the focus group sessions conducted immediately before and after the evaluation session. The resulting data were analyzed using discursive analysis, and the results were incorporated into the final assessment process. The method and the results are presented with recommendations for the use of expert panels in research projects and validation of assessment tools.