Determinants of income-earning strategies and adoption of conservation practices in hillside communities in rural Honduras

Based on the results of participatory diagnostic surveys conducted in 95 rural communities in the hillsides of Honduras, we determine income earning strategies at the community level; identify their main determinants; and analyze the adoption of of conservation practices. Eight income-earning strategies were distinguished that reflect differences in comparative advantage between communities. We explain the choice of income earning strategy using a multinomial logit model that includes biophysical, economic, social and institutional variables. We use a probit model to show that adoption of conservation practices is determined by the type of income earning strategy, population density, market access, and organizational variables.     

Rhinopneumonia or mycotoxin intoxication? Neurologic phenomena in horses from a riding school

In the course of several days most of the 40 riding-school horses turned out in paddocks developed ataxia of variable severity. Five of these horses showed severe ataxia and tremors, became paralyzed and were euthanized. Eleven privately-owned horses which were stabled on the same premises showed no clinical signs. The most likely diagnosis seemed to be the 'neurological form of EHV1', although the signs were not entirely typical. A few weeks later a second outbreak occurred among the riding-school horses and one of the privately-owned horses also showed signs of ataxia. In the meantime it had been shown that EHV1 titers in paired serum samples had not increased and that the cerebrospinal fluid of one of the severely affected horses was normal. Toxicological examination of hay, delivered just before the first outbreak and stored for the winter, showed a significantly increased concentration of lolitrem B mycotoxin (5-6 mg/kg). The hay appeared to have been made of ryegrass used for lawns and playing fields. Retrospectively it became probable that this hay occasionally been fed to the horses just before the onset of clinical problems. It is concluded that the horses showed the 'ryegrass-stagger syndrome'.     

Evaluation of pseudorabies viral antigens in the agar gel immunodiffusion test.

Procedures designed to extract pseudorabies viral (PRV) antigens from PRV-infected tissue cultures were investigated to determine whether differences in extraction method had an effect upon the final concentrated antigenic product. All four of the preparations made from PRV-infected tissue culture cells (trypsin extract and disrupted cells) or entire PRV-infected cultures (polysorbate 80 extract and (NH4)2SO4 precipitate) contained relatively large amounts of the same antigen, whereas cell-free PRV-infected tissue culture fluids did not contain significant amounts of this antigen. Specific antibody directed against this antigen was present in all PRV antisera tested. Two other antigens were observed in some of the preparations, but PRV antisera varied in their ability to precipitate with these antigens. Therefore, the number of precipitation lines observed in agar gel immunodiffusion between PRV preparations and PRV-positive antisera depended both upon the extraction method used to obtain the antigen and upon the specificity of the selected antiserum.     

Agronomic and Bioenergetic Consequences of Selection for High Groat-Oil Content and High Protein Yield in Oat*

Few studies have examined the effects of selection for high oil or protein content on the chemical composition of cereal seeds. This study was conducted to examine agronomic and bioenergetic consequences that result with changes in the chemical composition of groats of oat (Avena sativa L.). Oat lines with low and high groat-oil content (GO) and with low and high groat-protein content (GP) were chosen from each of five cycles of a recurrent selection program for increasing GO and from each of four cycles of a recurrent selection program for increasing protein yield via elevating GP, respectively. These lines were evaluated at three Iowa locations in 1988. The results indicated that GP was not significantly affected by selection for high GO and that GO significantly increased during selection for high protein yield via elevating GP. Both selection procedures resulted in oat lines with higher groat-energy contents. A bioenergetic cost analysis showed that for GO in the oil population and GP in the protein population to be increased, additional photosynthate needed to be available.     

Subsidence rates and carbon loss in peat soils following conversion to pasture in the Waikato Region, New Zealand

Abstract. Drainage of peat soils for agriculture can lead to large carbon losses due to oxidation of peat. We estimated peat subsidence rates and total carbon losses, due to 40 years of dairy farming on a former peat bog, by measuring the thickness of peat and total carbon of farmland and of an adjacent unmodified peat bog above a marker tephra layer that was deposited about 200 AD. Subsidence rates averaged 3.4 cm yr^–1 (95% confidence interval of 3.2 to 3.5 cm yr^–1) and carbon loss averaged 3.7 t ha^–1 yr^–1 (95% confidence interval of 2.5 to 5.0 t ha^–1 yr^–1). On average, 63% of the subsidence was due to consolidation, with the remainder (37%) attributed to losses of organic matter due to peat mineralization.     

Detection of Staphylococcus aureus in bulk tank milk using modified Baird-Parker culture media.

The purpose of this project was to evaluate the use of 2 selective/differential culture media for detecting Staphylococcus aureus in bulk tank milk. One medium was Baird-Parker agar base supplemented with egg york tellurite emulsion and acriflavine. The other medium was Baird-Parker agar base supplemented with rabbit plasma/bovine fibrinogen and acriflavine. An increased inoculum of bulk tank milk (0.3 mL) was used to enhance the detection of S. aureus in samples containing low numbers of organisms. The sensitivity and specificity for detecting S. aureus in bulk tank milk were 94.8% and 100%, respectively, using Baird-Parker agar base supplemented with egg yolk tellurite emulsion and acriflavine, and 89.7% and 100%, respectively, using Baird-Parker agar base supplemented with rabbit plasma/bovine fibrinogen and acriflavine. Both media are practical for detecting S. aureus in bulk tank milk and monitoring its spread in lactating dairy herds in Alberta.     

Effects of crude extracts of various plants on infectious bovine rhinotracheitis virus-plaque production.

Extracts of 28 plants were tested without demonstable antiviral activity in an agar-overlay plaque-reduction antiviral assay system, using infectious bovine rhinotracheitis virus and bovine endocardial cell cultures. Ethanolic extract of Narcissus tazetta L bulb elicited antiviral activity by inhibition of viral plaque formation. Antiviral activity was demonstrated against infectious bovine rhinotracheitis and equine rhinopneumonitis viruses. Narcissus tazetta L bulb did not directly inactivate the virus extracellularly. The extract exhibited only limited toxicity to rapidly multiplying bovine endocardial cells at plaque-inhibitory levels and was not cytoxic to preformed confluent cell monolayers. Narcissus extract did not induce the formation of drug-resistant viral strains.