Do Entrepreneurs Enhance Economic Growth in Lagging Regions?     

HEATHER M. STEPHENS  MARK D. PARTRIDGE 《Growth and change》2011,42(4):431-465

Because support for entrepreneurship is often a core part of economic development strategies, we investigate whether it is important for growth in lagging, rural U.S. regions by focusing on Appalachia. While entrepreneurship has the advantage of being endogenous and “home grown,” previous research suggests that remote rural regions may lack the agglomeration economies to benefit greatly from entrepreneurship. Using county‐level data, we explore the relationship between entrepreneurship and economic growth, employing self‐employment and small business data as proxies for entrepreneurship. We look at the results for the Appalachian Regional Commission (ARC) region, using its immediate Appalachian neighbors outside the ARC region as a control group. Moreover, we also account for self‐sorting by proprietors to locate in expanding regions. Despite strong barriers to growth in Appalachia, our empirical results suggest that self‐employment is positively associated with employment and income growth, and that efforts to promote entrepreneurial capacity may be among the few economic development strategies with positive payoffs in remote regions.  相似文献   

Effects of anti-inflammatory analgesic drugs and muscarinic receptor blocking agents on appetite in the pig     

H. C. BOWDEN  D. F. SHARMAN  D. B. STEPHENS † 《Journal of veterinary pharmacology and therapeutics》1987,10(3):269-272

  相似文献   

Application of formulated rhizobacteria against root rot of field pea     

K. XI  J. H. G. STEPHENS  & P. R. VERMA 《Plant pathology》1996,45(6):1150-1158

Formulations of bacterial biocontrol agents were evaluated for the control of pea root-rot caused primarily by Pythium ultimum and Rhizoctonia solani, at different levels of disease severity in field trials. Pseudomonas fluorescens (strain PRA25) in a peat-based formulation increased yield by 17% over the untreated, in a trial with light disease infection, and by 120% in another with moderate infection. Other bacteria including P . cepacia (strain AMMD) and fluorescent pseudomonads increased seedling emergence, and decreased disease incidence and severity, but with variable effects on yield when disease level was light to moderate. Biocontrol agents resulted in only limited control when disease was severe. Control with Captan did not differ significantly from that obtained with bacterial biocontrol agents. The application of Rhizobium granular inoculum together with PRA25 granules did not differ from other treatments in disease control, indicating that Rhizobium is compatible with biocontrol agents. The population dynamics of a fluorescent pseudomonad introduced into the rhizosphere in peat or granular formulation was monitored using an antibiotic-resistant mutant marker strain. The bacterium in peat formulation established a considerably higher population than that in granular formulation in 1993 trials, and a slightly higher population in 1994 trials. The higher population may have been responsible for the efficiency of root colonization and the effectiveness of disease control.  相似文献   

Cerebral dopamine, apomorphine and oral activity in the neonatal pig     

J. P. FRY  D. F. SHARMAN  D. B. STEPHENS 《Journal of veterinary pharmacology and therapeutics》1981,4(3):193-207

Neonatal piglets in which oral stimulation associated with feeding was reduced by intragastric tube feeding displayed an increase in stereotyped snout rubbing, licking and chewing behaviour. An investigation of a possible neurochemical basis for this behaviour was made by using sensitive radioenzymatic and micro-fluorimetric assays to estimate the concentrations of the catecholamines and of the dopamine metabolites homovanillic acid (HVA) and 3,4-dihydroxyphenyl-acetic acid (DOPAC) in different brain regions. These observations revealed that the increased non-nutritive oral activity of such piglets did not appear to be caused by an increased release of dopamine in the brain, since it was not associated with increases in the concentrations of the acidic metabolites of dopamine in either the caudate nucleus, the putamen, the nucleus accumbens, the olfactory tubercle, the hypothalamus, or the substantia nigra. The only neurochemical changes observed were small decreases in the concentration of HVA in the putamen and the nucleus accumbens. A lack of effect on catecholamine concentrations in any of the six brain regions examined suggested that the environmental manipulation caused no changes in the development of catecholamine-containing nerve endings.
Subcutaneous injection of apomorphine was found to increase the non-nutritive oral activity of piglets. Apparent conditioning effects of the environment on apomorphine-induced stereotyped behaviour however, prevented any satisfactory testing of possible changes in cerebral dopamine receptor sensitivity following reduced oral stimulation.  相似文献   

BOOK REVIEWS     

CP STEPHENS  JA GIBSON  PJ BLACKALL 《Australian veterinary journal》1990,67(12):466-466

Book reviewed in this article:
Guide to the Dissection of Domestic Ruminants . RE Habel
Biology and Medicine of Rabbits and Rodents . JE Harkness and JF Wagner  相似文献   

Diagnosis by ELISA of bovine abortion due to Campylobacter fetus     

S. HUM  LR STEPHENS  C. QUINN 《Australian veterinary journal》1991,68(8):272-275

An enzyme-linked immunosorbent assay (ELISA) was developed to detect antigen-specific secretory IgA antibody in bovine vaginal mucus after abortion due to Campylobacter fetus subsp venerealis. Abortions were diagnosed by isolating the organism from 8 foetuses and/or foetal membranes and by histopathology. Vaginal mucus was collected from 7 cows shortly after abortion. All showed a high level of IgA antibody in their vaginal mucus when they were compared with an uninfected control group. The new ELISA is simple and practical and provides a useful tool for diagnosis of bovine venereal campylobacteriosis.  相似文献   

Early-weaning and central nervous system pharmacology in piglets     

H. C. BOWDEN  D. F. SHARMAN  D. B. STEPHENS 《Journal of veterinary pharmacology and therapeutics》1987,10(4):346-348

  相似文献   

Phenotypic characterisation of Australian sheep and cattle isolates of Mannheimia haemolytica, Mannheimia granulomatis and Mannheimia varigena     

PJ BLACKALL  M. BISGAARD  CP STEPHENS 《Australian veterinary journal》2002,80(1):87-91

Objective To perform a comprehensive phenotypic characterisation of 35 isolates of bacteria previously identified as haemolytic Pasteurella‐Actinobacillus and obtained from cattle and sheep. Design The 35 isolates that had been obtained from Australian animals, 30 from cattle and five from sheep, were compared with reference strains of the five recognised species of the genus Mannheimia ‐ M haemolytica, M glucosida, M granulomatis, M ruminalis and M varigena. Results Thirty‐four of the isolates could be confidently assigned to three species of the genus Mannheimia. Twenty‐nine were M haemolytica, with 25 being isolated from cattle and four from sheep. All but three of the bovine M haemolytica were isolated from pneumonic lungs. Of the three remaining bovine M haemolytica isolates, one was obtained in pure culture from a bovine milk sample and the other two as part of a mixed flora associated with a middle ear infection of a calf suffering mucosal disease. Of the four ovine M haemolytica isolates, two were isolated in pure culture from milk and two, also in pure culture, from pneumonic lungs. Three bovine isolates were identified as M granulomatis ‐ one from a tongue abscess, one from a jaw abscess and one from a lung showing suppurative bronchopneumonia. Two bovine isolates were identified as M varigena‐ one coming from an udder and the other from a spleen. The available diagnostic records provided no information on whether these isolates were associated with a disease process. The remaining isolate was obtained from an ovine tongue abscess and could not be assigned to a recognised species within the genus Mannheimia. Conclusion The study represents the first time that M haemolytica, M granulomatis and M varigena have been recognised as being present in cattle and sheep in Australia. Veterinary laboratories that encounter Pasteurella‐Actinobacillus‐like organisms from cattle and sheep should attempt as complete a characterisation as possible to help improve our knowledge of the disease potential of these organsims.  相似文献   

Porcine pleuropneumonia in Australian pigs due to Actinobacillus pleuropneumoniae serovar 5     

CP STEPHENS  JA GIBSON  PJ BLACKALL 《Australian veterinary journal》1990,67(12):462-462

Book reviewed in this article: Guide to the Dissection of Domestic Ruminants . RE Habel Biology and Medicine of Rabbits and Rodents . JE Harkness and JF Wagner  相似文献   

Ultrasonographic and Endocrine Characterization of Follicular Waves in Llamas with a Special Reference to the Overlapping Phenomenon During Successive Waves     

MV Cavilla  CP Bianchi  C Maistruarena  MA Aba 《Reproduction in domestic animals》2013,48(6):923-930

Ovarian follicular growth in non‐mated llamas occurs in successive waves that generally superimpose their origin on the regression of the preceding wave (overlapping), originating prolonged sexual receptivity in the species. The aim of this study was to perform an ultrasonographic and endocrine characterization of individual and successive waves in non‐mated llamas with a special interest on the overlapping phenomenon. Twelve llamas were examined daily by transrectal ultrasonography for at least two consecutive waves. In six females, blood samples were collected daily at the end of each examination. The development of the largest follicle (F) showed a wavelike pattern with a mean duration of 25 days. All waves evaluated were partially overlapped on the preceding wave and emerged at a mean interval of 15.8 ± 0.5 days. This interwave interval determines a mean overlapping degree of 32% of the wave length. Similarly, mean plasma oestradiol‐17β (E₂) concentrations followed a wavelike pattern. However, E₂ concentrations started to decline before the structural regression of the F was observed. Mean basal E₂ concentrations remain higher than 10.9 ± 0.6 pmol/l. In conclusion, follicular activity in non‐mated llamas is characterized by continuous emergence of successive waves that always overlap the preceding wave with variable degrees. E₂ production during the follicular wave is shorter in duration than the morphological development of the F. Finally, the overlapping phenomenon maintains increased plasma E₂ concentrations persistently and this could explain the prolonged periods of sexual receptivity registered in llamas.  相似文献