Economic implications of a virus prevention program in deciduous tree fruits in the US     

Tiziano Cembali  Raymond J. Folwell  Philip Wandschneider  Kenneth C. Eastwell  William E. Howell 《Crop Protection》2003,22(10):1149-1156

Viral diseases in fruit trees present a potential danger that could injure the fruit industry, the planting stock industry (nurseries), and consumers in the United States and abroad. Currently, the US has a virus protection program (VPP) that serves to minimize the spread of viral diseases. This paper reports research estimating the economic consequences of the loss of the program on nurseries, growers and consumers. The potential economic losses are a measure of the value of the existing program. The paper focuses on apples, sweet cherries, and Clingstone peaches.

The effects of a loss of a VPP on nurseries would include direct and indirect losses from viral diseases in the form of lower quantity and quality of planting stocks. Fruit growers would be affected by reduced plant growth and fruit yield. Consumers would be affected by higher prices and reduced quantity of fruit.

We measured benefits of the virus prevention program as changes in consumer and producer surpluses. Empirical estimates were made using the method of avoided losses. Benefit estimates to three economic sectors—nurseries (avoided change in producer surplus), producers (avoided change in consumer and producer surpluses), and consumers (avoided change in consumer surplus)—were calculated. Total benefits for all three sectors were approximately $227.4 million a year, or more than 420 times the cost of the program. Our analysis utilizes a method that might be used to evaluate other programs that prevent the introduction of plant diseases.  相似文献   

The host status of the striped mouse, Rhabdomys pumilio, in relation to the tick vectors of heartwater in South Africa     

D J Howell  T N Petney  I G Horak 《The Onderstepoort journal of veterinary research》1989,56(4):289-291

Striped mice, Rhabdomys pumilio, were trapped over a 17 month period in the Thomas Baines Nature Reserve in the eastern Cape Province of South Africa. Captured mice were placed in cages, over water, and naturally detaching ticks were collected. Only 5 larvae and 1 nymph of Amblyomma hebraeum were recovered from the mice. These represented less than 0.1% of the total number of ticks recovered. No Amblyomma marmoreum were recovered. As the vegetation and large mammals and tortoises in the Thomas Baines Nature Reserve abound in larvae of both these vectors of heartwater the low infestation rates of R. pumilio indicate that it is either unsuitable or inaccessible for these ticks. R. pumilio is therefore unlikely to play a role in the epidemiology of heartwater.  相似文献   

Hematologic effects and feeding performance in cattle fed cull domestic onions (Allium cepa).     

S D Lincoln  M E Howell  J J Combs  D D Hinman 《Journal of the American Veterinary Medical Association》1992,200(8):1090-1094

For 119 days, 36 cattle, allotted to 6 treatment groups, were fed a balanced growth diet containing 0, 5, 10, 15, 20, or 25% cull onions on a dry-matter basis. Cattle performance was comparable to that associated with barley-base non-onion diet; statistical differences were not observed among treatments. During the first 28 days of the study, reduction in numbers of RBC, hemoglobin concentration, and PCV was observed in all cattle fed onions, but clinical anemia was not seen in any individual animal. After onion feeding was discontinued at 119 days, RBC numbers, hemoglobin concentration, and PCV returned to baseline values within 30 days. Heinz bodies were detected in erythrocytes of all cattle fed onions, and the percentage was proportional to the amount of onions consumed. Addictive onion consumption was prevented by mixing chopped or crushed onions in a total balanced ration.  相似文献   

Clinical foot-and-mouth disease in the African buffalo (Syncerus caffer)     

E Young  R S Hedger  P G Howell 《The Onderstepoort journal of veterinary research》1972,39(3):181-183

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Changes in concentrations of nitrogen and free and bound amino acids in alfalfa and pea infected by Ditylenchus dipsaci     

R K Howell  L R Krusberg 《Phytopathology》1966,56(10):1170-1177

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Homo habilis in Detail     

Howell FC 《Science (New York, N.Y.)》1991,253(5025):1294-1295

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The Effects of Live and Artificial Diets on Feeding Performance of Cultured Winter Flounder,Pseudopleuronectes americanus,in the Wild: Survival,Feeding, Growth,and Nucleic Acid Analyses          下载免费PDF全文

Michelle L. Walsh  Elizabeth A. Fairchild  Nathan Rennels  W. Huntting Howell  Renee Mercaldo‐Allen  Catherine Kuropat 《Journal of the World Aquaculture Society》2015,46(5):461-474

This research, which is part of a larger study designed to assess the feasibility of winter flounder, Pseudopleuronectes americanus, stock enhancement in New Hampshire, identifies hatchery feeds that optimize feeding‐related performance of fish once released in the wild. Fish reared on post‐nauplii of brine shrimp, Artemia sp., white worms, Enchytraeus albidus, common burrower amphipods, Leptocheirus plumulosus, and formulated pellets were evaluated post‐release from in situ cages using survival, growth rate, feeding onset and incidence, stomach fullness, diet composition, and nucleic acid‐based condition as indicators of hatchery diet suitability. Amphipod‐reared fish had the highest mean stomach content index of all feed types, including wild fish. Wild and worm‐reared fish exhibited the most similar survival, overall stomach fullness, and diet composition profiles over time. Amphipod‐reared fish ranked highest in overall performance; however, if wild fish performance is viewed as the ideal for a stocked fish, worm‐reared fish performed optimally. This study describes hatchery feeding strategies that may ease the transition of flatfish released into the wild for stock enhancement.  相似文献   

Introduction of Radioactive Sulfur (S35) Into the Penicillin Molecule by Biosynthesis     

Howell SF  Thayer JD  Labaw LW 《Science (New York, N.Y.)》1948,107(2777):299-300

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PTF 11kx: a type Ia supernova with a symbiotic nova progenitor     

B Dilday  DA Howell  SB Cenko  JM Silverman  PE Nugent  M Sullivan  S Ben-Ami  L Bildsten  M Bolte  M Endl  AV Filippenko  O Gnat  A Horesh  E Hsiao  MM Kasliwal  D Kirkman  K Maguire  GW Marcy  K Moore  Y Pan  JT Parrent  P Podsiadlowski  RM Quimby  A Sternberg  N Suzuki  DR Tytler  D Xu  JS Bloom  A Gal-Yam  IM Hook  SR Kulkarni  NM Law  EO Ofek  D Polishook  D Poznanski 《Science (New York, N.Y.)》2012,337(6097):942-945

There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi.  相似文献   

Fluoroquinolone resistance in Staphylococcus intermedius   总被引：1，自引：0，他引：1  

D.H. Lloyd  A.I. Lamport  W.C. Noble  & S.A. Howell 《Veterinary dermatology》1999,10(3):249-251

Four canine isolates of S. intermedius resistant to enrofloxacin were isolated amongst a total of 429 screened. Two of these were shown to exhibit resistance also to marbofloxacin and ciprofloxacin. Whilst molecular studies have shown the mechanism of resistance to these quinolone antibiotics to be similar in a number of staphylococcal species, it was not possible to confirm this mechanism in Staphylococcus intermedius .  相似文献