Responses to supplementation in white fulani cattle under agro-pastoral management in northern nigeria. II. Fodder     

D. A. Campbell  O. A. Ikuegbu  E. Owen  D. A. Little 《Tropical animal health and production》1996,28(3):230-236

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Florida manatees, Trichechus manatus latirostris, respond to approaching vessels     

Stephanie M Nowacek  Randall S Wells  Edward C.G Owen  Richard O Flamm 《Biological conservation》2004,119(4):517-523

Florida manatees inhabit shallow coastal and estuarine waters of the southeast US, a range that brings them into frequent contact with vessels. More than 30% of documented annual mortalities are attributed to vessel collisions, and most living animals bear the scars of multiple, non-lethal encounters. To document the behavior of manatees in the presence of vessels, we recorded their movements with an overhead video system. We scored six aspects of behavior during 170 vessel approaches, and compared their behavior with 187 control segments when no boats were present. Manatees in shallow waters and at the edge of the channel responded to approaches by orienting towards the nearest deep water, a boat channel, and increasing their swimming speed. Close boat approaches and shallow water depths exacerbated these responses. Our results indicate that manatees detect and respond to approaching vessels with an apparent flight response, a response which includes movement towards deeper water. If given sufficient time, i.e., approached or passed slowly, the manatees may then be able to reach deeper water and safe depths.  相似文献   

Long-term trends in stream chemistry and biology in North-East Scotland: Evidence for recovery     

C. Soulsby  D. Turnbull  S. J. Langan  R. Owen  D. Hirst 《Water, air, and soil pollution》1995,85(2):689-694

Since 1983 stream chemistry and macroinvertebrate ecology were monitored in ten streams draining the eastern Cairngorms. All streams have exhibited a decline in sulphate concentrations in response to reduced acid deposition; in the more acidic systems this has been reflected by a parallel increase in acid neutralizing capacity (ANC). In some streams this coincides with an increase in the abundance of acid-sensitive mayflies which may provide evidence for biological recovery. In the most chronically acidified systems no increased abundance has been observed despite significant increases in ANC. This suggests that further reductions in deposition and sufficient time for a reversal of soil acidification is required before any biotic recovery occurs.  相似文献   

Perceived risk, displacement and refuging in brown bears: positive impacts of ecotourism?     

Owen T. Nevin  Barrie K. Gilbert 《Biological conservation》2005,121(4):611-622

Ecotourism is a rapidly growing industry with unknown impacts on viewed wildlife that may require novel management action. We examined the impact of viewing activities on the behaviour of brown bears (Ursus arctos) in coastal British Columbia.Domination of the best feeding sites and human avoidance by large male bears has consistently been reported. We, however, saw displacement in time rather than space - during the viewing day large males were less active than at other times, while females with cubs tended to be more active.In each year, females with cubs spent similarly high proportions of their time fishing when people were present. In years with large male activity, less time was spent fishing when people were absent. When freed from the potential threat of large male bears, females with cubs showed no measurable impact of controlled human activity.Human presence at a feeding site impacts the behaviour of brown bears, but not as expected. Temporal avoidance of human activity by large males was observed; indications that they departed upon satiation, before the arrival of morning tours, however, suggests that there was little energetic impact. By displacing large males, viewing activities created a temporal refuge, enhancing feeding opportunities for subordinate age/sex classes. With the strong positive relationships between mean female mass and litter size, this may in turn increase population productivity.  相似文献   

Science and security. Practical experiences in dual-use review     

Davidson EM  Frothingham R  Cook-Deegan R 《Science (New York, N.Y.)》2007,316(5830):1432-1433

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Sex and population differences in the incidence of a plasma cholinesterase variant   总被引：2，自引：0，他引：2  

A H Lubin  P J Garry  G M Owen 《Science (New York, N.Y.)》1971,173(992):161-164

Accumulating knowledge of polymorphic enzyme systems poses intriguing possibilities of anthropologic genetics. Development of an automated procedure for determination of heterozygosity or homozygosity of the atypical plasma cholinesterase allele (E(1)(a)) permitted screening of 2317 individuals during a national Preschool Nutrition Survey and several smaller population studies. Frequencies of the allele (E(1)(a)) closely parallel those previously reported. Caucasians manifested a heterozygote male preponderance of 1.85: 1.  相似文献   

Temperatures, winds, and composition in the saturnian system     

Flasar FM  Achterberg RK  Conrath BJ  Pearl JC  Bjoraker GL  Jennings DE  Romani PN  Simon-Miller AA  Kunde VG  Nixon CA  Bézard B  Orton GS  Spilker LJ  Spencer JR  Irwin PG  Teanby NA  Owen TC  Brasunas J  Segura ME  Carlson RC  Mamoutkine A  Gierasch PJ  Schinder PJ  Showalter MR  Ferrari C  Barucci A  Courtin R  Coustenis A  Fouchet T  Gautier D  Lellouch E  Marten A  Prangé R  Strobel DF  Calcutt SB  Read PL  Taylor FW  Bowles N  Samuelson RE  Abbas MM  Raulin F  Ade P  Edgington S  Pilorz S  Wallis B  Wishnow EH 《Science (New York, N.Y.)》2005,307(5713):1247-1251

Stratospheric temperatures on Saturn imply a strong decay of the equatorial winds with altitude. If the decrease in winds reported from recent Hubble Space Telescope images is not a temporal change, then the features tracked must have been at least 130 kilometers higher than in earlier studies. Saturn's south polar stratosphere is warmer than predicted from simple radiative models. The C/H ratio on Saturn is seven times solar, twice Jupiter's. Saturn's ring temperatures have radial variations down to the smallest scale resolved (100 kilometers). Diurnal surface temperature variations on Phoebe suggest a more porous regolith than on the jovian satellites.  相似文献   

Jupiter's Atmosphere: Its Structure and Composition     

Greenspan JA  Owen T 《Science (New York, N.Y.)》1967,156(3781):1489-1494

Recent laboratory and observational data support the hypothesis that the composition of Jupiter's atmosphere is consistent with the relative abundances of the elements found in the sun. A model based on this assumption provides a reasonable interpretation of abundances of hydrogen and other gases obtained from studies of various regions of the planet's spectrum. Two presently unidentified absorptions may be caused by organic molecules in the Jovian atmosphere.  相似文献   

Prevention of vaginal SHIV transmission in rhesus macaques through inhibition of CCR5   总被引：1，自引：0，他引：1  

Lederman MM  Veazey RS  Offord R  Mosier DE  Dufour J  Mefford M  Piatak M  Lifson JD  Salkowitz JR  Rodriguez B  Blauvelt A  Hartley O 《Science (New York, N.Y.)》2004,306(5695):485-487

Topical agents, such as microbicides, that can protect against human immunodeficiency virus (HIV) transmission are urgently needed. Using a chimeric simian/human immunodeficiency virus (SHIV SF162), which is tropic for the chemokine receptor CCR5, we report that topical application of high doses of PSC-RANTES, an amino terminus-modified analog of the chemokine RANTES, provided potent protection against vaginal challenge in rhesus macaques. These experimental findings have potentially important implications for understanding vaginal transmission of HIV and the design of strategies for its prevention.  相似文献   

Polymorphism in pleistocene land snails     

Owen DF 《Science (New York, N.Y.)》1966,152(3718):71-72

Under suitable conditions the colors and patterns of the shells of land snails may be preserved for thousands of years. In a late Pleistocene population of Limicolaria martensiana all the major color forms that occur in modern living snails may be distinguished, and the basic polymorphism is at least 8,000 to 10,000 year old.  相似文献