Compositional stratification in the deep mantle   总被引：2，自引：0，他引：2  

Kellogg LH  Hager BH  van der Hilst RD 《Science (New York, N.Y.)》1999,283(5409):1881-1884

A boundary between compositionally distinct regions at a depth of about 1600 kilometers may explain the seismological observations pertaining to Earth's lower mantle, produce the isotopic signatures of mid-ocean ridge basalts and oceanic island basalts, and reconcile the discrepancy between the observed heat flux and the heat production of the mid-ocean ridge basalt source region. Numerical models of thermochemical convection imply that a layer of material that is intrinsically about 4 percent more dense than the overlying mantle is dynamically stable. Because the deep layer is hot, its net density is only slightly greater than adiabatic and its surface develops substantial topography.  相似文献   

Improvements to the dispersion status of piped gully soils following reworking and stabilisation by vegetation     

Hazel Faulkner   《CATENA》2007,70(3):410-415

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Hindsight in marine protected area selection: A comparison of ecological representation arising from opportunistic and systematic approaches     

Gretchen J.A. Hansen  Natalie C. Ban  Michael L. Jones  Les Kaufman  Hazel M. Panes  Maï Yasué  Amanda C.J. Vincent 《Biological conservation》2011,(6):1866-1875

Systematic approaches to site selection for marine protected areas (MPAs) are often favored over opportunistic approaches as a means to meet conservation objectives efficiently. In this study, we compared analytically the conservation value of these two approaches. We locate this study in Danajon Bank, central Philippines, where many MPAs were established opportunistically based on community preference, with few if any contributions from biophysical data. We began by identifying the biophysical data that would have been available when the first MPA was created in Danajon Bank (1995). We next used these data with the reserve selection software Marxan to identify MPAs that covered the same area as is protected under the current set of MPAs (0.32% of the total study area) and that would protect the greatest number of conservation targets at the lowest cost. We finally compared the conservation value of the current MPAs to the value of those selected by Marxan. Because of the dearth of biophysical data available in 1995 and the small area currently under protection, Marxan identified multiple configurations of MPAs that would protect the same percentage of conservation targets, with little differentiation among sites. Further, we discovered that the costs of obtaining and analyzing these data to be used for conservation planning would have been large relative to resources typically available to conservation planners in developing countries. Finally, we found that the current set of MPAs protected more ecological features than would be expected by chance, although not as many as could be protected using a systematic approach. Our results suggest that an opportunistic approach can be a valuable component of conservation planning, especially when biophysical data are sparse and community acceptance is a critical factor affecting the success of an MPA.  相似文献   

Can teaching veterinary and animal-science students about animal welfare affect their attitude toward animals and human-related empathy?     

Hazel SJ  Signal TD  Taylor N 《Journal of veterinary medical education》2011,38(1):74-83

Attitudes toward animals are important in influencing how animals are treated. Few studies have investigated attitudes toward animals in veterinary or animal-science students, and no studies have compared attitudes to animals before and after a course teaching animal welfare and ethics. In this study, students enrolled in veterinary (first-year) or animal-science (first- and third-year) programs completed a questionnaire on attitudes toward different categories of animals before and after the course. Higher attitude scores suggest a person more concerned about how an animal is treated. Normally distributed data were compared using parametric statistics, and non-normally distributed data were compared using non-parametric tests, with significance p < .05. Attitudes toward pets (45.5-47.6) were higher than those toward pests (34.2-38.4) or profit animals (30.3-32.1). Attitude scores increased from before to after the course in the veterinary cohort on the Pest (36.9 vs. 38.4, respectively, n = 27, p < .05) and Profit (30.3 vs. 32.1, respectively, n = 28, p < .05) subscales, but not in the animal-science cohorts. Attitude scores in all categories were higher for women than for men. Currently having an animal was associated with higher pet scores (46.8 vs. 43.8, ns = 120 and 13, respectively, p < .05), and having an animal as a child was associated with higher profit scores (31.0 vs. 26.6, ns = 129 and 8, respectively, p < .05). Students electing to work with livestock had lower scores on the Pest and Profit subscales, and students wanting to work with wildlife had significantly higher scores on the Pest and Profit subscales. This study demonstrates attitudinal changes after an animal-welfare course, with significant increases in veterinary but not animal-science students.  相似文献   

Rundschau     

RD i. R. Dr. Edmund Leib 《Journal of pest science》1984,57(6):118-119

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Ceroid-lipofuscinosis in miniature Schnauzer dogs     

RD JOLLY  RH SUTTON  RIE SMITH  DN PALMER 《Australian veterinary journal》1997,75(1):67-67

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Normal expression of adhalin and merosin in ovine congenital progressive muscular dystrophy     

RD JOHNSEN  NG LAING  CR HUXTABLE  BA KAKULAS 《Australian veterinary journal》1997,75(3):215-216

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Genetic parameters for selected beef-carcass traits     

P O Brackelsberg  E A Kline  R L Willham  L N Hazel 《Journal of animal science》1971,33(1):13-17

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Flea (Ctenocephalides felis) control efficacy of topical indoxacarb on dogs subsequently bathed with a chlorhexidine–ketoconazole shampoo          下载免费PDF全文

RD Armstrong  JE Liebenberg  K Heaney  F Guerino 《Australian veterinary journal》2015,93(8):293-294

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Initiation of Plant Disease Resistance by Physical Interaction of AvrPto and Pto Kinase   总被引：7，自引：0，他引：7  

X Tang  RD Frederick  J Zhou  DA Halterman  Y Jia  GB Martin 《Science (New York, N.Y.)》1996,274(5295):2060-2063

Resistance to bacterial speck disease in tomato occurs when the Pto kinase in the plant responds to expression of the avirulence gene avrPto in the Pseudomonas pathogen. Transient expression of an avrPto transgene in plant cells containing Pto elicited a defense response. In the yeast two-hybrid system, the Pto kinase physically interacted with AvrPto. Alterations of AvrPto or Pto that disrupted the interaction in yeast also abolished disease resistance in plants. The physical interaction of AvrPto and Pto provides an explanation of gene-for-gene specificity in bacterial speck disease resistance.  相似文献