Factors affecting the nutrient status of forest sites in a mountain watershed in Nepal

Soil and foliage samples were collected from 136 sample sites in forested areas of the Dhulikhel Watershed, Nepal. Analyses showed that the soils have small values for pH, base saturation, total nitrogen, carbon and available phosphorus. Sample sites were stratified on the basis of aspect and elevation, soil type, forest type and management and the strata were compared to determine the influence of site factors on forest soil fertility. Soils on south-facing slopes at low elevation contained significantly less total nitrogen and organic carbon compared with soils from north-facing slopes at high elevation. Foliage of both sal (Shorea robusta Gaertn.) and chir pine (Pinus roxburghii Sargent) growing on red soils (Rhodustults and Haplustults) contained significantly less phosphorus compared with non-red soils (Ustochrepts and Dystrochrepts). Soils under stands of sal have the poorest soil fertility levels in comparison with chir pine and hardwood sites. The continuous removal of base-rich litter from sal sites may account for the poor fertility conditions. Soil fertility levels are greater on sites which have been protected from biomass removal for at least 15 years relative to sites which have come under protection in the past 7 years.     

BEKÄMPFUNG VON GALIUM APARINE MIT MECOPROP IN ABHÄNGIGKEIT VON VERSCHIEDENEN BODENARTEN

Summary. The control of Galium aparine L. with post-emergence sprays of mecoprop depends not only on the plant size, but also on the soil in which the plants are growing:

• 1 Small plants were more readily killed than large ones.
• 2 Plants growing in a soil with a high organic content were more resistant to mecoprop than those growing in a soil with a lower organic content.
• 3 Part of the post-emergence spray reached the soil and had an additional effect through root uptake.
• 4 This effect was less in two soils with a high organic content than in one with a lower organic content. The reason for this was the greater adsorption of mecoprop by the high-organic soils.
• 5 Only the organic matter was concerned in the adsorption.

The full herbicidal effect of mecoprop thus involves activity through the soil in addition to uptake through the foliage. La lutte contre le Galium aparine avec le mécoprop enfonction du type de sol     

The Direct Injection Technique for Preparing the Spray Mix - A Method for Reducing Safety and Hygiene Problems in Plant Protection?1

In the past, industry and research institutes have produced a number of technical proposals to improve sprayer technique, and development in this area has been very successful. The «closed sprayer-system>>, the pesticide flushing system, flow regulation systems and updated stirring arrangement are examples of many different practicable improvements. A completely new approach to improving application technique is the « direct injection of pesticides >>: contrary to normal practice the tank of the sprayer is filled with pure water only. The pesticide is introduced in concentrate form into a separate tank and injected into the water flow produced by the equipment pump during the application process. The advantages of this technique include no direct handling of the active substance concentrate; no problems with liquid-stirring; no pesticide residues. A commercial sprayer equipped with a metering device prototype and a newly developed constant pressure fitting is described as an illustrative example of prospective design of a « direct-injection >> system. A number of other technical possibilities exist for putting this method into practice. The advantages of this technique have to be paid by an additional capital outlay but they offer the chance to reduce safety and hygiene problems in chemical plant protection.     

Intraocular lead foreign bodies in four canine eyes

Retained intraocular lead foreign bodies are well tolerated by the canine eye. Three cases (four eyes) of intraocular lead shot are the subject of this report.     

我国禽用活疫苗生产SPF化势在必行

改革开放以来,随着我国畜牧业持续、健康和稳定的发展,畜产品质量与产量显著提高.据统计,2006年畜牧业总产值约1.4万亿元,占农业总产值的34%.肉、蛋、奶产量分别达到7 980、2 940和3 290万吨,比2000年分别增长58.8%、25.8%和193%,我国肉、蛋总产量已名列世界首位,奶产量跃居世界第五位.畜牧业的成就与我国畜禽疫病防治水平的提高密不可分,由于我国养殖业的生物安全管理比较差,主要靠疫苗免疫接种防控畜禽疫病.免疫接种安全、高效的疫苗是防控家禽疫病的关键,而实行禽用活疫苗的SPF化生产是保证疫苗纯净安全、有效的重要手段.……     

Optimizing Electrical Activation of Porcine Oocytes by Adjusting Pre‐ and Post‐Activation Mannitol Exposure Times

Modifying electrical activation conditions have been used to improve in vitro embryo production and development in pigs. However, there is insufficient information about correlations of porcine embryo development with oocyte pre‐ and post‐activation conditions. The purpose of this study was to compare the developmental rates of porcine oocytes subjected to different mannitol exposure times, either pre‐ or post‐electrical activation, and to elucidate the reason for the optimal mannitol exposure time. Mannitol exposure times around activation were adjusted as 0, 1, 2 or 3 min. Blastocyst development were checked on day 7. Exposure of oocytes to mannitol for 1 or 2 min before electrical activation produced significantly higher blastocyst rates than exposure for 0 or 3 min. There was no significant difference in blastocyst rates when activated oocytes were exposed to mannitol for 0, 1, 2 or 3 min after electrical activation. While exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation showed significantly higher blastocyst development than 0 min pre‐ and 0 min post‐activation. It also showed higher maintenance of normal oocyte morphology than exposure for 0 min pre‐ and 0 min post‐activation. In conclusion, exposure of oocytes to mannitol for 1 min pre‐ and 3 min post‐activation seems to be optimal for producing higher in vitro blastocyst development of porcine parthenogenetic embryos. The higher blastocyst development is correlated with higher maintenance of normal morphology in oocytes exposed to mannitol for 1 min pre‐ and 3 min post‐activation.     

Distribution and biomass of an underfished vendace, Coregonus albula, population in a mesotrophic German reservoir

Abstract  The distribution and overall biomass of an underfished vendace, Coregonus albula L., population in the mesotrophic Henne Reservoir (Germany) was studied using hydroacoustics and gill nets. Additionally, midwater trawling was carried out. Overall fish biomass, based on five hydroacoustic surveys (June to September 2002), ranged from 188 kg ha⁻¹ in early August to 302 kg ha⁻¹ in September 2002. The overall mean fish biomass was 256 kg ha⁻¹ (±48 kg ha⁻¹ SD). Biomass of fish smaller than 25 cm total length (mostly vendace) varied from 56 kg ha⁻¹ in August to 99 kg ha⁻¹ in September, with an overall mean fish biomass of 74 kg ha⁻¹ (±17 kg ha⁻¹ SD). The echograms showed temporal variation in fish distribution in Henne Reservoir. In June, fish were fairly evenly distributed over the whole reservoir but in September a dense aggregation of fish (mostly vendace) was found in the deeper water layers near the dam. The distribution of vendace stock, its impact on water quality and fisheries management, biomanipulation and effort for mass removal are discussed.     

Colliding beam fusion reactor

Recent results with Tokamak experiments provide insights into the problem of magnetic confinement. They demonstrate how to avoid anomalous transport and thus solve the major problems of Tokamak reactors: size, the production of 14-megaelectron volt neutrons, and maintenance. An alternate confinement system, the field-reversed configuration, confines beams of protons and boron-11. For the proton-boron-11 fusion reaction, the fusion products are all charged particles for which direct conversion is feasible and neutron flux is negligible.     

Discrimination of successiveness: a test of a model of attention

Interpreting attention as a periodic phenomenon, we show its relevance to discriminating the successiveness of signals presented to separate sense modalities. Experiments confirm the expected linear relation between the probability of discriminating pairs of successive from pairs of simultaneous signals and make it possible to infer the period of attention.