Incubation of chicken eggs at altitude theoretical consideration of optimal gas composition     

A. H. J. Visschedijk  H. Rahn 《British poultry science》1981,22(5):451-460

1. Eggs from sea level which are transferred to higher altitude for incubation require changes in incubator gas composition if they are to develop normally.

2. This not only requires compensation for the reduced O₂ partial pressure but, and of equal importance, recognition of the increased diffusivity of gases at altitude.

3. Equations are developed for predicting the required changes in O₂, CO₂ and water vapour composition of incubator gas at any altitude.  相似文献   

Co-incorporation of biodegradable wastes with crop residues to reduce nitrate pollution of groundwater and decrease waste disposal to landfill     

C. R. Rahn    G. D. Bending    R. D. Lillywhite  & M. K. Turner 《Soil Use and Management》2009,25(2):113-123

Return of high nitrogen (N) content crop residues to soil, particularly in autumn, can result in environmental pollution resulting from gaseous and leaching losses of N. The EU Landfill Directive will require significant reductions in the amounts of biodegradable materials going to landfill. A field experiment was set up to examine the potential of using biodegradable waste materials to manipulate losses of N from high N crop residues in the soil. Leafy residues of sugar beet were co‐incorporated into soil with materials of varying C:N ratios, including molasses, compactor waste, paper waste, green waste compost and cereal straw. The amendment materials were each incorporated to provide approximately 3.7 t C per hectare. The most effective material for reducing nitrous oxide (N₂O) production and leaching loss of NO₃^? was compactor waste, which is the final product from the recycling of cardboard. Adding molasses increased N₂O and NO₃^? leaching losses. Six months following incorporation of residues, the double rate application of compactor waste decreased soil mineral N by 36 kg N per hectare, and the molasses increased soil mineral N by 47 kg N per hectare. Compactor waste reduced spring barley grain yield by 73% in the first of years following incorporation, with smaller losses at the second harvest. At the first harvest, molasses and paper waste increased yields of spring barley by 20 and 10% compared with sugar beet residues alone, and the enhanced yield persisted to the second harvest. The amounts of soil mineral N in the spring and subsequent yields of a first cereal crop were significantly correlated to the lignin and cellulose contents of the amendment materials. Yield was reduced by 0.3–0.4 t/ha for every 100 mg/g increase in cellulose or lignin content. In a second year, cereal yield was still reduced and related to the cellulose content of the amendment materials but with one quarter of the effect. Additional fertilizer applied to this second crop did not relieve this effect. Although amendment materials were promising as tools to reduce N losses, further work is needed to reduce the negative effects on subsequent crops which was not removed by applying 60 kg/ha of fertilizer N.  相似文献   

The impact of mowing as a management strategy for wet meadows on spider (Araneae) communities     

Marie-France Cattin  Carolin Banašek-Richter 《Biological conservation》2003,113(2):179-188

Meadows are often managed by mowing to prevent succession and brushwood encroachment. This management practice is efficient to maintain plant diversity, but the effect on arthropod groups is less well known. We sampled spiders in the Grande Cariçaie (Switzerland), a site of nature conservation importance, in two types of wet meadows, an unmanaged site and one 2-years-old mown conditions. Numbers of individuals for the most abundant families, diversity measures, and indicator taxa were compared among vegetation and treatment types. The results indicate that the less mobile spiders and species linked to litter or dead reeds, including rare species, are reduced by mowing. Present management consists in triennial mowing of 2-4 ha non-contiguous sectors. We investigate the conflict between the need to mow the meadows to maintain them, and the negative effect of mowing on spider communities. We therefore propose a new management scheme aimed at maintain the vegetation while lessening its negative effects on spider communities by providing refuges.  相似文献   

On the activity of blood histamine levels and leukocyte count in rabbits with Aujeszky's disease     

C H Becker  H W Rahn 《Archiv fuer experimentelle veterinaermedizin》1965,19(4):1111-1119

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Bruchpilot promotes active zone assembly, Ca2+ channel clustering, and vesicle release   总被引：1，自引：0，他引：1  

Kittel RJ  Wichmann C  Rasse TM  Fouquet W  Schmidt M  Schmid A  Wagh DA  Pawlu C  Kellner RR  Willig KI  Hell SW  Buchner E  Heckmann M  Sigrist SJ 《Science (New York, N.Y.)》2006,312(5776):1051-1054

The molecular organization of presynaptic active zones during calcium influx-triggered neurotransmitter release is the focus of intense investigation. The Drosophila coiled-coil domain protein Bruchpilot (BRP) was observed in donut-shaped structures centered at active zones of neuromuscular synapses by using subdiffraction resolution STED (stimulated emission depletion) fluorescence microscopy. At brp mutant active zones, electron-dense projections (T-bars) were entirely lost, Ca2+ channels were reduced in density, evoked vesicle release was depressed, and short-term plasticity was altered. BRP-like proteins seem to establish proximity between Ca2+ channels and vesicles to allow efficient transmitter release and patterned synaptic plasticity.  相似文献   

Evidence of plaggen soils in SW Norway          下载免费PDF全文

Carolin Schnepel  Kerstin Potthoff  Sebastian Eiter  Luise Giani 《植物养料与土壤学杂志》2014,177(4):638-645

This study aimed at clarifying whether a notable group of soils of the Jæren region, SW Norway, with deep humus‐rich top soils support a man‐made genesis. Four sites were investigated. The soils are characterized by thick top soils of 45, 70, 80, and 90 cm, which are enriched in soil organic matter and often also in artifacts, like fragments of potter's clay, indicating an anthropogenic origin. Soil pH ranges from 5.4 to 6.2 (H₂O) and 4.4 to 5.3 (CaCl₂), respectively. Soil organic C (SOC) contents range from 6.4 to 51.6 g kg^?1 and N contents vary between 0 and 2.9 g kg^?1. Increased P contents of up to 2,924.3 mg kg^?1 total P (P_t) and 1,166.4 mg kg^?1 citric acid‐soluble phosphorus (P_c) in the humus‐rich top soils support the assumption of an anthropogenic influence. Although many characteristics indicate an anthropogenic genesis, one soil lacks the required depth of 50 cm of a plaggen horizon and cannot be classified as Plaggic Anthrosol (WRB) and Plagganthrept (US Soil Taxonomy). As the requirement is 40 cm in the German system, all soils can be classified as Plaggenesch. The formation of these soils is related to human activity aiming at increasing soil fertility and overcoming the need of bedding material, the basic aims of the plaggen management in Europe. Highest P contents ever found for this kind of soils and references from the literature indicate that the formation of the soils in Norway started at Viking time, hence, being older than most other Plaggic Anthrosols.  相似文献   

Morphological and immunohistochemical characteristics of the equine corneal epithelium     

Eva Kammergruber  Carolin Rahn  Barbara Nell  Simone Gabner  Monika Egerbacher 《Veterinary ophthalmology》2019,22(6):778-790

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An indirect hemagglutination test for the diagnosis of Eperythrozoon suis infection in swine.   总被引：12，自引：0，他引：12  

A R Smith  T Rahn 《American journal of veterinary research》1975,36(9):1319-1321

An indirect hemagglutination test was developed to detect naturally occurring eperythrozoonosis in swine and to follow experimentally induced infections serologically. The antigen used was prepared from the plasma of acutely infected, splenectomized pigs. The test was specific and reliable in detecting swine latently infected with the disease.  相似文献   

Effect of Five Municipal Waste Derived Composts on a Cereal Crop     

R.D. Lillywhite  M.E. Dimambro  C.R. Rahn 《Compost science & utilization》2013,21(3):173-179

Agricultural soils were amended with five mixed feedstock (four source segregated and one mechanical biological treatment) municipal waste derived composts to investigate the effect on a cereal crop over two years. Composts were applied at two rates to contain either 250 or 500 kg nitrogen ha^?1 and compared to a control which received no fertilizer. In year one, three of the composts increased barley yield (by up to 21%), compared to the control (no compost and no fertilizer) and two reduced it (by up to 33%). Application of the municipal waste derived compost resulted in greater nitrogen concentration in the grain and 1000 grain weight but reduced nitrogen uptake and yield. Application of composts had no significant effect on levels of lead, nickel and cadmium in the barley grains. Levels of soil potentially toxic elements were not significantly increased by application of the composts. In year two, all composts gave comparable or greater wheat yields in comparison to the control.  相似文献   

Land use history and historical soil erosion at Albersdorf (northern Germany) — Ceased agricultural land use after the pre-historical period     

Stefan Reiß  Stefan Dreibrodt  Carolin Clara Marie Lubos  Hans-Rudolf Bork 《CATENA》2009

The Holocene landscape history and historical soil erosion were reconstructed at Albersdorf (Schleswig-Holstein, Germany) from soils and colluvial layers. In contrast to many landscapes in central Europe, agricultural land use and soil erosion were more frequent during pre-historical times, whereas it has almost ceased after the advent of history. Pre-historical soil erosion rates from about 0.1 to 6.9 t ha^− 1 a^− 1 were reconstructed with no significant differences between the prehistoric cultural phases. The study of buried soils within the soil/soil-sediment-sequences provided evidence for an acceleration of soil formation processes probably as a consequence of excessive prehistoric woodland pasture on poor sandy soils.  相似文献