Sensitivity of alpine stream ecosystems to climate change and human impacts

• 1 Climatic changes and water resource developments alter the relative contribution of the water sources (glacier-melt, snow-melt, rainfall run-off and springflow) to the discharge regime of alpine streams.
• 2 Likely changes in the magnitude and variability of a range of climatic determinants of glacier behaviour, as a result of an enhanced Greenhouse Effect, are shown to have important implications for the future hydrogeomorphological and thermal dynamics of alpine streams.
• 3 Zoobenthic communities typically show deterministic patterns in alpine streams due to the over-riding influence of water temperature and channel stability. These communities could act as indicators of change in the relative contribution of run-off, particularly to alterations of glacier-melt patterns.
• 4 A reduction of glacial meltwater, following diversion for HEP generation, is used as an example to illustrate the sensitivity of the zoobenthic communities to changes in temperature and flow regimes, and geomorphological dynamics.

     

Damselfish as keystone species in reverse: intermediate disturbance and diversity of reef algae

Substrates located within the defended territories of Hawaiian damselfish for 1 year were subjected to intermediate grazing intensity and, as a result, showed greater diversity of algae than substrates either protected within fish-exclusion cages or exposed to intense fish grazing outside territories. Thus, this damselfish enhances local diversity on reefs through "intermediate-disturbance" effects, and is a keystone species that decreases rather than increases overall predation intensity relative to areas where it is absent.     

Small-scale jetlike features in penumbral chromospheres

We observed fine-scale jetlike features, referred to as penumbral microjets, in chromospheres of sunspot penumbrae. The microjets were identified in image sequences of a sunspot taken through a Ca II H-line filter on the Solar Optical Telescope on board the Japanese solar physics satellite Hinode. The microjets' small width of 400 kilometers and short duration of less than 1 minute make them difficult to identify in existing observations. The microjets are possibly caused by magnetic reconnection in the complex magnetic configuration in penumbrae and have the potential to heat the corona above a sunspot.     

The influence of nitrate,water potential and oxygen tension on nitrogen fixation in detached pea roots

Nodulated pea roots were detached from the plant shoots and exposed to different nitrate concentrations, water potentials, and oxygen tensions. The rates of nitrogen fixation in the detached pea roots following these treatments were determined by the acetylene reduction assay. It was found that increasing the nitrate concentration up to 5 mM brought about reduced nitrogen fixing activity, and this occurred independently of the depressing effects of low water potential and low oxygen tension.

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Auszug Mit Knöllchenbakterien behaftete Erbsenwurzeln wurden von den Pflanzen abgetrennt und verschiedenen Nitratkonzentrationen, Wasserpotentialen und Sauerstoff-Tensionen ausgesetzt. Die Mengen an fixiertem N wurden nach den verschiedenen Behandlungen in den abgetrennten Erbsenwurzeln durch den Azetylen-Reduktionstest bestimmt.Vermehrte Nitrat-Konzentration bis zu 5 mM brachte eine reduzierte Aktivität in der N-Fixierung hervor. Dies war unabhängig vom depressiven Effekt des niedrigen Wasserpotentials und der niedrigen Sauerstoff-Tension.

     

Serologic correlation of suspected Leptospira interrogans serovar pomona-induced uveitis in a group of horses

After the observation of 2 horses with uveitis on a horse farm in the Minnesota River valley, 100 horses from this geographic area were given ophthalmologic examinations and were evaluated serologically for leptospirosis. A statistically significant (P less than 0.001) association was observed between the finding of antibodies against Leptospira interrogans serovar pomona and uveitis.     

Use of Internet-based resources to support an introductory animal and poultry science course.

This article describes the development and implementation of a World Wide Web page to support a team-taught introductory animal and poultry science course. The objectives were to examine the capabilities of this type of instructional resource, determine students' willingness to use this type of resource, create opportunities for interactive learning, and improve students' enthusiasm for the subject area. A variety of course materials were made available through the Internet, including the class syllabus, lecture notes, and practice questions to support and augment class lectures. Additional on-line resources included a bulletin board for instructor announcements, a list-serve for student discussions concerning administrative and educational issues arising during the semester, a class E-mail list, and a page with links to other sites of agricultural interest. Materials were accessible from a variety of computer resources, including campus computing laboratories, dial-up access, and access via other Internet service providers. Use of the materials was evaluated by analysis of log files from the server. Effectiveness of the resources was determined from surveys of students conducted before and after implementation of the on-line resource. Students indicated that the most useful components of the Web page were the class notes and practice/review questions. Effectiveness of the site was related to the amount of material available through the site, the level of interaction, whether the task was required, and the ease of access to computers and the Web site. Student evaluations indicated that this form of instructional supplement is a viable method for enhancing the learning experience in the introductory animal sciences.     

LESIONS CAUSED BY CORYNEBACTERIUM PSEUDOTUBERCULOSIS IN THE SCROTUM OF RAMS

SUMMARY Palpable lesions within the scrotum but not associated with the testis or epididymis were detected in 20 of 200 merino rams in 3 flocks during routine veterinary examination. In 13 of 15 rams further examined Corynebacterium pseudotuberculosis was isolated from the lesions, which were typical CLA type abscesses. C. pseudotuberculosis was not shed in semen, and semen quality was normal in all affected rams.     

Field release of a non-toxigenic Aspergillus flavus L strain in central Benin

Journal of Plant Diseases and Protection - Non-toxigenic strains of Aspergillus flavus (Link) can be used as biological control agents to reduce the contamination of grains such as maize with...