冀西北坝上地区大蒜播种期研究

为了探讨冀西北坝上地区大蒜适宜的播种期,给当地大蒜高效生产提供理论依据,试验以大蒜品种西八里为试验材料,设置A(3月22日)、B(4月1日)、C(4月11日)3个不同播期,测定了不同播期下大蒜的生育期、植株性状、蒜头性状、蒜薹和蒜头产量等指标。结果表明,播期B和C较播期A的出苗时间分别缩短7 d和11 d;播期B的植株性状、蒜头性状均优于播期A和C,播期B一级蒜的比例最高,较播期A、C分别高出11.0和27.6个百分点;播期B较播期A和C的蒜薹产量分别提高8.41%和40.82%,蒜头产量分别提高10.19%和16.08%。本试验条件下,坝上地区大蒜适宜的播种期为3月底至清明节之间。     

Sodicity‐induced land degradation and its sustainable management: problems and prospects

Currently at least 20 per cent of the world's irrigated land is salt‐affected. However, projections of global population growth, and of an increased demand for food and fibre, suggest that larger areas of salt‐affected soil will need to be cropped in the future. About 60 per cent of salt‐affected soils are sodic, and much of this land is farmed by smallholders. Ameliorating such soils requires the application of a source of calcium (Ca²⁺), which replaces excess sodium (Na⁺) at the cation exchange sites. The displaced Na⁺ is then leached from the root zone through excess irrigation, a process that requires adequate flows of water through the soil. However, it must now be recognized that we can no longer conduct sodic soil amelioration and management solely with the aim of achieving high levels of crop productivity. The economic, social, and environmental impacts of different soil‐amelioration options must also be considered. A holistic approach is therefore needed. This should consider the cost and availability of the inputs needed for amelioration, the soil depth, the level to which sodicity needs to be reduced to allow cropping, the volume and quality of drainage water generated during amelioration, and the options available for drainage‐water disposal or reuse. The quality and cost of water available for post‐amelioration crops, and the economic value of the crops grown during and after amelioration should also be taken into account, as should farmers' livelihoods, the environmental implications of amelioration (such as carbon sequestration), and the long‐term sustainable use of the ameliorated site (in terms of productivity and market value). Consideration of these factors, with the participation of key stakeholders, could sustainably improve sodic soil productivity and help to transform such soils into a useful economic resource. Such an approach would also aid environmental conservation, by minimizing the chances of secondary sodicity developing in soils, particularly under irrigated agriculture. Copyright © 2006 John Wiley & Sons, Ltd.     

Salicylate-induced seizures in a dog

A 10-year-old, mixed-breed, castrated male dog was examined because of acute onset of vomiting followed by severe generalized seizures. The dog had been on a treatment regimen that included a salicylate-containing drug, and the owners unknowingly supplemented aspirin. Supportive treatment utilizing sodium bicarbonate resulted in return to normal within 24 hours. Blood salicylate concentrations were determined to be in the range toxic to human beings.     

First results on the incorporation and excretion of 15N from orally administered urea in lactating pony mares

Two lactating pony mares were given oral offers of 20 g 15N urea [95 atom-% 15N-excess (15N')] on 6 subsequent days. About 80% of the consumed 15N' were excreted via urine and faeces, but only about 2% via milk. The 15N' secreted via milk-lysine only amounted to 0.04% of the 15N' intake. The recovery was about 90% in each case. Tissues with active metabolism had an unexpectedly high labelling (greater than 0.3 atom-% 15N'). The low extent of the conversion of oral urea N into milk-lysine speaks against an essential participation of the enteral synthesis in meeting the amino acid requirement of lactating mares. It was already concluded from this results that the determination of the amino acid requirement will be necessary for this group of performance.     

Eiweißernāhrung des Menschen unter besonderer Berücksichtigung des Pflanzeneiweißes

Ohne Zusammenfassung     

Tissue Expansion in Pig Skin – A Histochemical Approach

In the present study, a porcine model for controlled skin expansion was investigated to improve our understanding of epidermal and vascular responses following stretching. The model is of outstanding importance not only for the clinical use of tissue expansion but provides interesting data for skin physiology and oncology, too. Thirteen out of 15 animals, who underwent silicone tissue expander implantation showed good clinical results. In all of them, skin biopsies were taken at the end of a controlled tissue expansion procedure (final expander volumes 350 or 500 ccm): one tissue specimen was obtained from the centre of the expanded skin area and a second from the neighbouring but nonexpanded skin. The tissue specimens were immediately frozen in liquid nitrogen and processed to 4 microns thick acetone-fixed frozen sections. Lectin histochemistry and immunohistology were performed using the following techniques: direct and indirect immunofluorescence technique (DIFT, IIFT), immunoperoxidase technique (POX) with either 3,3'-diamino-benzidine (DAB) or 3-amino-9-ethyl-carbazole (AEC). The histochemical findings were supplemented by measurements of the number of vital epidermal cell layers, the epidermal thickness (microns), and the papillary vascular count per visual field. There was a significant diminuation of the vascular count (mean +/- S.D. = 55.0% +/- 12.5%; U-test: p less than 5%). By immunohistochemistry, a loss of the basal cell reactivity for the following antibodies was noted: ACAM (against calmodulin), K 8.12 (against keratins 13 +/- 16) and A51-B/H4 (against keratins 8, 14, 18). There was a remarkable increase of filaggrin expression in the uppermost spinal cell layers in expanded skin, which was most pronounced in those specimens with the shortest interval to the last fluid injection into the expander. We gained no evidence for alterations of the expression of suprabasal epidermal keratins, lectin binding sites (UEA I, PNA, ConA, WGA), and vascular lectin- and immunoreactivity due to tissue expansion. The subdermal capsule, which had formed around the silicone expander, was strongly vimentin-reactive. In conclusion, controlled tissue expansion is capable to change the basal cell phenotype--a feature which is shared with a number of conditions with increased proliferative activity and with the epidermis covering different skin tumours. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation. Furthermore, the porcine skin is a reliable model for studying physiology and pathophysiology of human skin.     

Solid-state light sources getting smart

More than a century after the introduction of incandescent lighting and half a century after the introduction of fluorescent lighting, solid-state light sources are revolutionizing an increasing number of applications. Whereas the efficiency of conventional incandescent and fluorescent lights is limited by fundamental factors that cannot be overcome, the efficiency of solid-state sources is limited only by human creativity and imagination. The high efficiency of solid-state sources already provides energy savings and environmental benefits in a number of applications. However, solid-state sources also offer controllability of their spectral power distribution, spatial distribution, color temperature, temporal modulation, and polarization properties. Such "smart" light sources can adjust to specific environments and requirements, a property that could result in tremendous benefits in lighting, automobiles, transportation, communication, imaging, agriculture, and medicine.     

Conventional and alternative housing systems for poultry--point of view of infectious disease medicine

The use of conventional battery cages for hens will be prohibited in Germany in 2007. Only few studies, however, have considered the differences between battery cages and alternative systems with regard to infectious diseases. The existing gaps in the current knowledge need to be closed by research and measures must be developed that will prevent the spread of viral, bacterial, and parasitic infections in alternative poultry housing systems.With regard to virus infections, avian influenza requires particular attention. Since wild birds, particularly anseriformes, represent a reservoir for avian influenza viruses, free-ranging poultry is much more at risk of infection than birds in closed hen-houses. Appropriate measures must prevent direct contact with wild birds and transmission via contaminated water, feed, or equipment. Several bacterial infections of poultry represent zoonoses. Salmonella and Campylobacter are considered as particularly important. To avoid a potential increase in the risk of infection for consumers due to poultry keeping systems that might favour infections with bacterial zoonotic agents, there is a special need for research in this area. With regard to parasitic infections, coccidioses may cause problems in alternative poultry housing systems, and lead to considerable economic consequences. The epidemiological situation concerning infections with Histomonas meleagridis needs to be analysed. Since all compounds that had been used for prophylactic or therapeutic purposes in the past have been banned, there is a need to develop new drugs which are safe for animals and humans.