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81.
Dairy feeding systems in many semi-arid countries are based on imported concentrates and forages. This has economic and ecological implications given the increase in global feed prices and greenhouse gas (GHG) emissions from land use change. This paper aims to explore alternative dairy feeding systems under semi-arid conditions, using Jordan as an example. The feedings systems under investigation vary in their share of food industry by-products (replacing concentrates in the diet) and are compared against the current concentrate-based feeding systems. The systems are evaluated against three criteria: their nutritional value, their impact on the cost of milk production, and their GHG mitigation potential. Feed samples from eleven food industry by-products and ten conventional feeds were collected from food factories and from three typical dairy farms, representing the typical large-, medium- and small-scale farm types, respectively. Feed samples were analysed for their chemical composition and metabolisable energy contents. In addition, economic and production farm data were collected and entered into a model for GHGs calculation and economic evaluation. The results suggest that inclusion of locally available food industry by-products in the rations of milk cows in semi-arid production systems can be instrumental in reducing production costs and mitigating GHG emissions. Cost of milk production in the model farms can be lowered by up to 14 %; mitigation of CO2 eq. emission ranged between 70 and 290 g CO2 eq./kg milk. The degree to which these benefits can be reaped is positively related to the level of inclusion of by-product feeds in lactating cows’ diets.  相似文献   
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Maternal uniparental disomy (UPD) 20 was found in a 35-month-old girl, the product of a pregnancy complicated by a prenatal diagnosis of mosaic trisomy 20. Phenotypic abnormalities included pre- and postnatal growth failure, microcephaly, minor dysmorphic features and psychomotor developmental delay. Chromosomal analysis on cord blood revealed only a normal 46,XX karyotype. Microsatellite analysis of 27 chromosome 20 loci confirmed maternal UPD for all 11 informative markers. Maternal heterodisomy was detected in two and maternal isodisomy in three loci. In the remaining six loci, a non-informative maternal UPD pattern was displayed, as mother and proband are homozygous for the same allele. To our knowledge this is the first reported case of maternal disomy 20 with normal karyotype ascertained by a mosaic trisomy 20 pregnancy. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
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Solid bioenergy from forests plays — and is expected to continue to play — a key role to fulfil the renewable energy targets at the European Union level. When the Renewable Energy Directive was enacted, sustainability criteria were incorporated solely for biofuels and bioliquids. Sustainability criteria for solid bioenergy are also needed in order to prevent wood and primary forest residues from posing additional environmental risks to ecosystems. Acknowledging this, the European Commission has been working on extending the biofuels and bioliquids provisions to solid biomass. An internal draft was circulated in August 2013 which addressed the ways to both balance and mitigate the risks in three main topics: biodiversity; sustainable forest management; and greenhouse gases. This paper presents a set of criteria and indicators, developed during workshops with experts from Governments, scientific institutions, businesses and NGOs, that may be considered by the EU to assure that solid biomass from forests is obtained in an environmentally sustainable way.  相似文献   
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The accumulation of carbon dioxide in the atmosphere will lower the pH in ocean waters, a process termed ocean acidification (OA). Despite its potentially detrimental effects on calcifying organisms, experimental studies on the possible impacts on fish remain scarce. While adults will most likely remain relatively unaffected by changes in seawater pH, early life-history stages are potentially more sensitive, due to the lack of gills with specialized ion-regulatory mechanisms. We tested the effects of OA on growth and development of embryos and larvae of eastern Baltic cod, the commercially most important fish stock in the Baltic Sea. Cod were reared from newly fertilized eggs to early non-feeding larvae in 5 different experiments looking at a range of response variables to OA, as well as the combined effect of CO2 and temperature. No effect on hatching, survival, development, and otolith size was found at any stage in the development of Baltic cod. Field data show that in the Bornholm Basin, the main spawning site of eastern Baltic cod, in situ levels of pCO2 are already at levels of 1,100 μatm with a pH of 7.2, mainly due to high eutrophication supporting microbial activity and permanent stratification with little water exchange. Our data show that the eggs and early larval stages of Baltic cod seem to be robust to even high levels of OA (3,200 μatm), indicating an adaptational response to CO2.  相似文献   
88.
In search of the sky compass in the insect brain   总被引:2,自引:0,他引:2  
Like many vertebrate species, insects rely on a sun compass for spatial orientation and long- range navigation. In addition to the sun, however, insects can also use the polarization pattern of the sky as a reference for estimating navigational directions. Recent analysis of polarization vision pathways in the brain of orthopteroid insects sheds some light onto brain areas that might act as internal navigation centers. Here I review the significance, peripheral mechanisms, and central processing stages for polarization vision in insects with special reference to the locust Schistocerca gregaria. As in other insect species, polarization vision in locusts relies on specialized photoreceptor cells in a small dorsal rim area of the compound eye. Stages in the brain involved in polarized light signaling include specific areas in the lamina, medulla and lobula of the optic lobe and, in the midbrain, the anterior optic tubercle, the lateral accessory lobe, and the central complex. Integration of polarized-light signals with information on solar position appears to start in the optic lobe. In the central complex, polarization-opponent interneurons form a network of interconnected neurons. The organization of the central complex, its connections to thoracic motor centers, and its involvement in the spatial control of locomotion strongly suggest that it serves as a spatial organizer within the insect brain, including the functions of compass orientation and path integration. Time compensation in compass orientation is possibly achieved through a neural pathway from the internal circadian clock in the accessory medulla to the protocerebral bridge of the central complex.  相似文献   
89.
Transformation of crops, including maize (Zea mays L.), with the cry1Ab gene from Bacillus thuringiensis to combat lepidopteran pests results in pleiotropic effects regarding lignin biosynthesis. Lignin patterns in stems and leaves of two genetically modified Bt-maize varieties (Novelis T and Valmont T) were studied along with their non-Bt near-isolines (Nobilis and Prelude, respectively). Molecular-level based thermochemolysis using tetramethylammonium hydroxide (TMAH) in combination with gas chromatography-mass spectrometry (GC-MS) was used to quantitate the total lignin contents and to identify monomeric lignin subunits including p-hydroxyphenyl (P), guaiacyl (G), and syringyl (S) moieties. The results were supplemented and confirmed by cupric oxide oxidation. The stems of the transgenic lines had higher concentrations of total lignin than the respective isogenic lines: Valmont T/Prelude by 18% and Novelis T/Nobilis by 28%. In contrast, differences in the total lignin concentration of leaves between the transgenic and the respective near-isogenic lines were marginal. There were significant modifications in the ratio of p-hydroxyphenyl/guaiacyl/syringyl molecular marker units of stem lignin between transgenic and isogenic lines. The guaiacyl units (in particular the G18 marker) accounted chiefly for the higher total lignin contents in the transgenic lines. The leaf lignin patterns did not show significant differences in molecular markers between isogenic and transgenic lines. TMAH-induced thermochemolysis--conducted in both the on-line and off-line modes--provided detailed information on the molecular composition of lignin, thus proving superior to the established "wet chemistry" methods of lignin determination.  相似文献   
90.
The activated sludge respiration inhibition test is an important bacterial test system for the determination of bacterial toxicity of chemical compounds. The exposure period recommended by OECD 209 and ISO 8192 protocols is 30 and 180 min. A modified version of the test was developed which allowed a prolonged incubation period of 27 h to enhance the possibilities of the test system. The test system with the prolonged incubation time was evaluated by the recommended reference compound 3.5-dichlorophenol and showed an EC50 of 6.3 mgl(-1) with a coefficient of variation of 12.7%. Furthermore, the use of an open test system was evaluated showing a comparable toxicity but a higher coefficient of variation than the closed test system. A storage of activated sludge for several days accompanied by a daily feed with OECD nutrient solution should be avoided, for it can cause a decreased sensitivity of the inoculum. Different statistical fit procedures were tested indicating that Weibull fit procedures were superior for extended data sets covering a wide range of concentrations whereas Gamma and Probit fits were appropriate for smaller data sets mainly restricted to the linear part of the dose response curve.  相似文献   
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