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51.
The increasing demand for renewable energy feedstock has raised interest in growing eucalypts for fuel wood production, which is achieved by establishing very dense plantations cut every 18–24 months. The high moisture content of fresh Eucalyptus may handicap cut-and-chip operations, and offers a unique opportunity for supply chains based on baling. Therefore, the Canadian-made BioBaler was tested in Brazil on a eucalypt energy plantation, as well as on the resprouts generated by a conventional pulpwood plantation after severe frost damage. The BioBaler coped well with both crops, achieving high productivity levels: 7.1 and 3.3 t h?1 in the energy plantation and the failed crop treatments, respectively. Harvesting cost was estimated at €13 t?1 and €26 t?1 for the energy plantation and the failed crop, respectively. Productivity and harvesting cost were comparable with those reported in previous studies conducted in other countries on similar crops. Productivity was directly proportional to field stocking. Future studies should test the machine on a wider range of work conditions and include bale extraction, storage, processing and transportation, in order to estimate an overall supply chain cost and allow direct comparison with alternative options.  相似文献   
52.
The results of massively parallel three-dimensional molecular dynamics simulations of the perpendicular intersection of extended dislocations in copper are reported. The intersection process, which involves three of the four possible 111 glide planes in the face-centered cubic lattice, begins with junction formation, followed by unzipping, partial dislocation bowing, cutting, and, finally, unit jog formation. The investigation provides insights into this complex atomistic process, which is currently not accessible to experimental investigation.  相似文献   
53.
Before its broad application in practice, housing equipment should be tested, in particular with regard to animal welfare. The differing positions of the German Federal Council (Bundesrat) and the German Federal Parliament (Bundestag), whether such testing should be mandatory or voluntary, have been conciliated in the amended animal welfare act by empowering the Federal Ministry of Food, Agriculture and Fisheries (BML) to fix official standards for voluntary testing procedures by regulation. On request of the BML, a report as scientific basis for a draft regulation is currently prepared by the scientific animal welfare committee of the German Agricultural Society (DLG). The scientific animal welfare committee has been appointed by the DLG in order to provide support in the effort to strengthen animal welfare aspects in the DLG-utility testing procedure of housing equipment, which is in place since 1953. The committee elaborates standards concerning testing methods, assessment criteria and the necessary size of investigations. As required, the scientific animal welfare committee may support the DLG-testing bodies in the implementation of the animal welfare part of the testing procedure. It will, moreover, be involved in the welfare assessment based on the testing results. The amendments of the already established testing procedure will help to fulfill the general requirements on an acceptable animal welfare testing procedure. While keeping in mind that there are certain limits in what can be achieved by a voluntary testing procedure, the enhanced consideration of animal welfare aspects within the DLG-utility testing procedure has the advantage to be relatively unbureaucratic and in line with EU legislation, and is, therefore, an appropriate tool for a contibrution to improved animal welfare in livestock housing.  相似文献   
54.
Ovarian Follicular Dynamics in Buffalo Cows (Bubalus bubalis)   总被引:1,自引:0,他引:1  
Follicular growth in Egyptian buffalo cows was monitored using genital tracts from 200 buffalo cows collected immediately after slaughter. According to the morphological appearance of the corpus luteum (CL), the corresponding oestrous cycle was divided into four stages: A (days 1–4), B (days 5–10), C (days 11–17) and D (days 18–21). Within these stages the follicular population on the ovaries was evaluated and the dominant follicle (DF) determined in all recovered ovaries. The functional status of the DF and the largest sub‐dominant follicles was examined by histological examination in 31 cases, and Radio Immunoassay (RIA) analyses for estradiol‐17β (E2) and progesterone (P4) was performed in the follicular fluid in 23 of the DF. The results showed that DFs changed their endocrine character within the stages of the oestrous cycle. The DFs between days 5 and 10 were functionally active (E2‐dominant; non‐atretic) in most of the cases. Between days 11 and day 17 half of the DFs became functionally inactive (P4‐dominant; atretic). At days 18–21 all of the DF became functionally active and non‐atretic. In the specimens that carried two large follicles one of them was regularly atretic and P4‐dominant whereas the other was non‐atretic and E2‐dominant. Between days 18 and 21 all ovaries examined showed at least one large follicle. These findings suggest that in most of the cases follicular dynamics occurs in two wave‐like patterns in the Egyptian buffalo cows.  相似文献   
55.
Malocclusions are a misalignment or incorrect positioning of the teeth when the upper and lower jaws close. These are poorly described in the koala and can result in irregular mastication which can have lifelong effects on body condition and oral health. A total of 370 koalas from two populations in Queensland (295) and one in South Australia (75) were examined for malocclusions. The prevalence of malocclusions in South Australian free‐ranging koalas, captive Queensland koalas and Queensland free‐ranging koalas was 39% (44), 30% (29) and 22% (29) respectively. Four types of malocclusion were identified based on severity of misalignment of the incisor/canine region, types 1, 2, 3 and 4. Maxillary overbite measurements of the molariform teeth were determined and these anisognathic values were then used to describe malocclusions within familial relationships in captive colonies. Captive koalas with a malocclusion had narrower mandibular width that ranged between 0.5 and 1% less than the normal measurements. The specific malocclusions reported in this study affected individuals by leading to tooth rotation, mobility and erosion with inefficient mastication of food and vegetation compaction. These changes increased the oral cavity pathology, by placing animals at risk of periodontal disease. There was evidence of familial links to malocclusion types in captive animals. Therefore captive breeding recommendations should consider known koala malocclusion traits to minimise their effect on future generations.  相似文献   
56.
Objective  To remodel and validate commercially available monitors and their Pitot tube-based flow sensors for use in large animals, using in vitro techniques.
Study design  Prospective, in vitro experiment.
Methods  Both the original and the remodelled sensor were studied with a reference flow generator. Measurements were taken of the static flow-pressure relationship and linearity of the flow signal. Sensor airway resistance was calculated. Following recalibration of the host monitor, volumes ranging from 1 to 7 L were generated by a calibration syringe, and bias and precision of spirometric volume was determined. Where manual recalibration was not available, a conversion factor for volume measurement was determined. The influence of gas composition mixture and peak flow on the conversion factor was studied.
Results  Both the original and the remodelled sensor showed similar static flow–pressure relationships and linearity of the flow signal. Mean bias (%) of displayed values compared with the reference volume of 3, 5 and 7 L varied between −0.4% and +2.4%, and this was significantly smaller than that for 1 L (4.8% to +5.0%). Conversion factors for 3, 5 and 7 L were very similar (mean 6.00 ± 0.2, range 5.91–6.06) and were not significantly influenced by the gas mixture used. Increasing peak flow caused a small decrease in the conversion factor. Volume measurement error and conversion factors for inspiration and expiration were close to identity.
Conclusion  The combination of the host monitor with the remodelled flow sensor allowed accurate in vitro measurement of flows and volumes in a range expected during large animal anaesthesia.
Clinical relevance  This combination has potential as a reliable spirometric monitor for use during large animal anaesthesia.  相似文献   
57.
Wood is a major pool of organic carbon that is highly resistant to decay, owing largely to the presence of lignin. The only organisms capable of substantial lignin decay are white rot fungi in the Agaricomycetes, which also contains non-lignin-degrading brown rot and ectomycorrhizal species. Comparative analyses of 31 fungal genomes (12 generated for this study) suggest that lignin-degrading peroxidases expanded in the lineage leading to the ancestor of the Agaricomycetes, which is reconstructed as a white rot species, and then contracted in parallel lineages leading to brown rot and mycorrhizal species. Molecular clock analyses suggest that the origin of lignin degradation might have coincided with the sharp decrease in the rate of organic carbon burial around the end of the Carboniferous period.  相似文献   
58.
59.
Different transgenic potato lines were generated for improving the nutritional value of tubers by an advanced perception of their sulphur metabolism. So far no data exist about possible implications for plant health and stress resistance. Metabolite analysis revealed that modifications of enzymes involved in sulphur metabolism were necessarily not reflected in distinctly altered thiol contents. The release of H2S by plants is putatively involved in pathogen resistance, because of its fungi‐toxic mode of action. The emission of H2S was determined in 16 potato lines with modified expression level in ATP sulphurylase (ATPS), serine acetyltransferase (SAT), O‐acetylserine(thiol)lyase (OASTL), homoserine kinase (HSK) and threonine synthase activities. The emission significantly increased by factor 7 in one of the ATPS antisense lines and by factor 8 in one of the OASTL antisense lines. A strong increase in H2S emissions was observed in transgenic plants based on the potato cultivar White Lady, which expressed the Escherichia coli SAT. In addition, the exchange of COS was determined in relation to genetic modifications. Generally, plants act as a sink for COS, but all transgenic lines expressing the E. coli HSK and one of the ATPS antisense lines emitted COS indicating to strong changes in the metabolism of these plants. Such alterations in the gas exchange of transgenic potato plants will most likely also affect their resistance against biotic and abiotic stress.  相似文献   
60.
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