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301.
Solid-state light sources getting smart 总被引:2,自引:0,他引:2
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. 相似文献
302.
Conraths FJ Werner O Methner U Geue L Schulze F Hänel I Sachse K Hotzel H Schubert E Melzer F Mettenleiter TC 《Berliner und Münchener tier?rztliche Wochenschrift》2005,118(5-6):186-204
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. 相似文献
303.
Abstract– The southern cavefish ( Typhlichthys subterraneus Girard) is a small troglobitic fish found in a few disjunct populations in the central United States. Protecting and managing these populations requires a knowledge of southern cavefish microhabitat requirements, including their preference for substrate. We conducted tests of their preferences for cobble, gravel, pea gravel, and sand substrates in two-way and multiple choice experiments for extended periods using time-lapse video photography. Cobble proved to be the substrate these fish preferred to occur within. In nature, this preference may provide cavefish increased foraging opportunities and/or refuge from high flows associated with flooding. Our results indicate the need to (1) maintain coarse substrate as an integral part of cavefish habitats, and (2) direct cavefish censusing attempts towards such key areas. 相似文献
304.
305.
Groups of male and female Cairina ducks subjected to equal starter feeding (1st to 3rd weeks) were used from the 4th week of live (fattening period) to test feed mixes of varying energy and crude protein levels (480 energetic feed equivalents/heu[EFH] - 140 g crude protein[CP]; 480 EFh - 180/g CP; 555 EFh - 140 g CP; 555 EFh - 180 g CP; 625 EEh - 140 g CP; 625 EFh - 180 g CP - all figures referred to 1 kg of feed). The different energy levels remained without influence of the live weight development. High-energy feed caused, however, higher expenditures of energetic feed equivalents per kg of gain and resulted in carcases with higher fat proportion. At all the 3 energy levels under study, high-protein feeding proved superior to low-protein rations with regard to live weight gains and meat yield. For the time being, 500 EFh and 180 g CP per kg of organic matter are recommended as indicators for Cairina duck fattening rations. 相似文献
306.
307.
Separate sedimentary populations are not all characterized by lognormal size distributions. Populations of different sizes of material are produced by different mechanisms of abrasion: pebbles and gravel by singlestage crushing; sand by repeated abrasion; and silt and clay by chipping from larger grains. Each mechanism imposes a different size distribution on the product. 相似文献
308.
EOS Batista GG Macedo RV Sala MDDV Ortolan MF Sá Filho TA Del Valle EF Jesus RNVR Lopes FP Rennó PS Baruselli 《Reproduction in domestic animals》2014,49(3):448-452
In Bos taurus cattle, antimullerian hormone (AMH) has been demonstrated to have a high degree of correlation with ovarian antral follicle count and the number of healthy follicles and oocytes. To document the correlation between the plasma concentration of AMH and follicular number in Bos indicus and Bos taurus heifers, Nelore (Bos indicus, n = 16) and Holstein heifers (Bos taurus, n = 16) had their ovarian follicular waves synchronized. After synchronization, ovarian antral follicular population (AFP) was evaluated three times at 60‐day (d) intervals (T‐120 d, 120 days before plasma AMH determination; T‐60 d, 60 days before; and T0, at the time of plasma AMH determination). The plasma AMH concentration was positively correlated with the number of ovarian follicles on the day of the follicular wave emergence in Bos indicus (Nelore) and Bos taurus (Holstein) heifers at each evaluation time (p < 0.05). The AFP was higher in Bos indicus (Nelore) than in Bos taurus (Holstein) heifers (p < 0.05). Similarly, the AMH concentration was higher in Bos indicus (Nelore) than in Bos taurus (Holstein) heifers (p < 0.0001). When heifers were classified as to present high or low AFP according to the mean of the AFP within each genetic group, high‐AFP heifers presented a greater (p < 0.0001) AMH concentration than low‐AFP heifers, regardless of the genetic group. In conclusion, the AFP is positively correlated with plasma AMH concentration in both Bos indicus (Nelore) and Bos taurus (Holstein) heifers. Furthermore, Bos indicus (Nelore) heifers presented both greater plasma AMH concentrations and AFP than Bos taurus (Holstein) heifers. 相似文献
309.
Summary We established a chromosome specific DNA library of the Aegilops markgrafii chromosome B. Eight microdissected chromosomes B obtained from a monosomic T. aestivum-Aegilops markgrafii addition line were PCR-amplified and the DNA was cloned in Escherichia coli DH5. Clones were characterized by dot blot hybridization with total Ae. markgrafii DNA. 62% of clones represented repetitive sequences and 38% low or single copy sequences. The estimated length of excised inserts varied between less than 200 bp and more than 500 bp. The average size of inserts was 310 bp.Abbreviations bp
base pairs
- DOP-PCR
degenerated oligonucleotide primed polymerase chain reaction 相似文献
310.
Schubert G Smith BF Sonett CP Colburn DS Schwartz K 《Science (New York, N.Y.)》1974,183(4130):1194-1197
High-frequency (5 to 40 millihertz) induced lunar magnetic fields, observed at the Apollo 15 site near the southeastern boundary of Mare Imbrium and the southwestern boundary of Mare Serenitatis, show a strong tendency toward linear polarization in a direction radial to the Imbrium basin and circumferential to the Serenitatis basin, a property that could be indicative of a possible regional influence on the induction. 相似文献