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1.
In a large part of the literature on Scbumpeter one finds thatattention is paid to either his early contributions, with referenceto the role of the entrepreneur as the personification of innovation,or to his later contributions, stressing the role of large companiesas main drivers of innovation. This paper complements some recentcontributions to the assessment of the influence of Schumpeteron economics and social sciences in general. It demonstratesthat a careful reading of his writings reveals that there isno simple dichotomy between the old and the young.Entrepreneurial activities play an active role in understandingthe dynamics of innovation throughout Schumpeter's theory. 相似文献
2.
H. YOUNG P. FELLOWS J. MITCHELL 《International Journal of Food Science & Technology》1985,20(6):689-695
International aid agencies undertake supplementary feeding programmes following disasters in order to alleviate or prevent protein energy malnutrition. The associated problems include lack of facilities for preparation and distribution of food on site and food hygiene dangers. In response to these factors a biscuit of high calorific value and acceptable organoleptic qualities has been developed. It is currently being used by Oxfam as part of their disaster relief programme in Ethiopia. 相似文献
3.
Factors affecting the tendency of thawed blueberries to leak pigmented exudate were investigated. Drip and anthocyanin leakage rates (ALR) were determined spectrophotometrically. Leakage vs time curves were linear or two-phase linear, ALR varying with cultivar, ripeness, and berry condition. Dewaxing increased ALR with most cultivars. ALR did not correlate with berry anthocyanin content, surface area, or cuticle thickness. ALR and amount of drip were poorly correlated. ALR varied from berry-to-berry within samples. Leakage was observed to be nonuniform on berry surfaces, appearing at skin cracks and ruptures, the calyx area, and other point sources. An hypothesis relating leakage to skin condition, fluid accumulation, and anthocyanin content is presented. 相似文献
4.
A study of the prevalences of Salmonella, Listeria and thermophilic campylobacters in a dedicated commercial poultry feed mill was undertaken. Salmonella was frequently recovered in samples taken in the preheat and postheat treatment areas of the mill with the overall percentage of samples positive found to be 18.8% and 22.6%, respectively. Feed ingredients and dust collected in the preheat treatment locations within the mill were frequently contaminated with Salmonella (11.8% and 33.3% of samples, respectively). High prevalences of Salmonella were also detected in dust samples (24.2%) obtained from the postheat treatment area of the mill and from feed delivery vehicles (57.1%).
Listeria was also recovered from samples at pre- and postheat treatment areas within the mill with overall isolation rates of 14.1% and 18.5% observed, respectively. The most frequently observed species of Listeria recovered from samples in both areas within the mill was L. innocua, L. monocytogenes, L. grayi and L. welshimeri.
No thermophilic campylobacters were recovered from any of the samples analyzed in the current study. 相似文献
Listeria was also recovered from samples at pre- and postheat treatment areas within the mill with overall isolation rates of 14.1% and 18.5% observed, respectively. The most frequently observed species of Listeria recovered from samples in both areas within the mill was L. innocua, L. monocytogenes, L. grayi and L. welshimeri.
No thermophilic campylobacters were recovered from any of the samples analyzed in the current study. 相似文献
5.
CYSTINE LYASES IN PLANTS: A COMPREHENSIVE REVIEW 总被引:1,自引:0,他引:1
Cystine lyases cleave L-cystine through aβ-elimination reaction producing thiocysteine (cysteine persulfide), pyruvate and ammonia. They are responsible for the initial reaction that produces characteristic flavors and aromas in important vegetables of the genus Brassica. In this review, an overview of these plant C-S lyases, comparison with alliin lyases andβ-cystathionases, purification protocols, substrate specificity, function and biochemical characteristics will be discussed. The importance of these enzymes to food science will also be examined. 相似文献
6.
7.
JOHN E. RITTER THOMAS H. SERVICE KARL JAKUS 《Journal of the American Ceramic Society》1988,71(11):988-992
Long-term static fatigue behavior of optical glass fibers is controlled by their strength, fatigue resistance, and zerostress aging behavior. The effectiveness of four special coatings in preventing the long-term static fatigue deterioration of optical glass fibers was evaluated by determining the dynamic fatigue behavior and the effects of zero-stress aging on strength of the four specially coated optical glass fibers in water from 25° to 85°C. The results clearly show that the strength, fatigue resistance, and aging behavior varied significantly between these specially coated fibers. By analysis of these experimental results in terms of fracture mechanics principles, the predicted static fatigue behaviors of the four fibers were compared. Ideally the optimum fiber is one that exhibits a high strength, low strength variability, high fatigue resistance, and high aging resistance. Each of these specially coated fibers had a deficiency in at least one of these properties. 相似文献
8.
PAUL PREDECKI J. HAAS JOHN FABER Jr. R. L. HITTERMAN 《Journal of the American Ceramic Society》1987,70(3):175-182
The mechanism of lattice thermal expansion in pure hexagonal cordierite prepared by glass devitrification was investigated by time-of-flight neutron powder diffraction at temperatures from 22° to 750°C under vacuum. Full matrix least-squares refinement of the diffraction spectra was carried out in space group P6/mcc using the Rietveld method. The structural data from the refinements were resolved into components parallel and normal to the c axis. The negative c axis expansion results from two effects: (1) increasing distortion of the T2 tetrahedral (ring tetrahedra) with temperature, primarily due to displacement of the T2 cations toward the c-axis channels in the structure; (2) decreasing distortion of the T1 /M tetrahedra/ octahedra with increasing temperature, due to octahedral I (M-O1 ) bond expansion and an associated decrease in torsional distortion of the T1 tetrahedra. 相似文献
9.
G. SCOTT GLAESEMANN JOHN E. RITTER Jr. KARL JAKUS 《Journal of the American Ceramic Society》1987,70(9):630-636
Mixed-mode failure of soda-lime glass under inert and fatigue test conditions was studied using Knoop indentation flaws. For annealed cracks (residual stress-free) crack extension (catastrophic or subcritical) is by an abrupt transition from the initial crack plane to a noncoplanar crack plane followed by a reorientation of the crack normal to the applied stress. Although fatigue strength of these inclined flaws increased linearly with respect to orientation of the flaws to the applied stress up to an angle of 60°, this increase was considerably less than what was predicted by existing theories. It is believed that subcritical crack growth causes the crack to be realigned perpendicular to the applied stress before failure for all orientations; hence, fatigue strength does not show the dramatic increase at orientation angles as predicted by theory. For as-indented cracks the contact residual stress causes the crack extension to be less inclined to the initial crack plane than for annealed cracks, but in this case also, the crack realigns itself perpendicular to the applied stress. Again, fatigue strength is relatively insensitive to the orientation angle as predicted by theory and subcritical crack growth is believed to play a primary role in determining this strength dependency. 相似文献
10.
The grain-boundary diffusion product, D'δ , of 51 Cr in MgO and Cr-doped MgO as a function of grain-boundary orientation and point-defect concentration was determined at T =1200° to 1450°C. A large degree of anisotropy was found in the grain-boundary diffusion behavior in MgO. The ratio of D'δ|| parallel to D'δ‖ perpendicular to the growth direction, D'|| /D'‖ , is 102 for a 5° (100) tilt boundary, decreased to ∼2 in boundaries with tilt angles > 10°. The decrease in D'|| /D'‖ is due to a large increase in D'‖ with increasing tilt angle. The results indicate that grain-boundary diffusion in MgO is connected to the orientation of dislocations and the mechanism is one of dislocation pipe diffusion. The grain-boundary diffusion product D'δ increases with increasing Cr concentration in MgO and is ∼4 times larger for MgO containing 0.56 at. % Cr than for the undoped MgO. For all bicrystals studied, the activation energies are within 180 ± 20 kJ/mol which is 60% of the activation energy for 51 Cr diffusion in undoped MgO. 相似文献