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31.
Holland JL 《Science (New York, N.Y.)》1957,126(3271):433-437
An analysis of the college attendance or college choice for four high-aptitude, high-school senior samples suggests that the differential institutional productivity of scientists and scholars is a function of the differential college attendance, paternal vocational motivations, and their implied correlates among high-aptitude students. This formulation appears to be more probable for males than for females. The institutional productivity hypothesis proposed in previous studies is not supported by the present evidence (14). 相似文献
32.
Holland HD 《Science (New York, N.Y.)》1997,275(5296):38-39
A recent study by Mojzsis et al., (Nature 384, 55, 1996) found evidence of life in rocks in Greenland estimated by new isotopic data to be more than 3800 million years old. The author examines this study in relation to studies conducted on rocks between 3250 and 3800 million years old and presents reasons to agree and disagree with the interpretation of data. 相似文献
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Holland CT 《The Journal of small animal practice》2005,46(1):22-26
A three-month-old dobermann was presented with hyperfiexion of the right carpus. The abnormality had evolved over a three-week period, following circumferential soft tissue trauma to the distal brachium. The carpal joint angle measured at the limit of passive extension was 105 degrees compared with 175 degrees for the left carpus, and prevented placement of metacarpal and digital pads on the ground. Neurological examination revealed marked atrophy of the carpal extensors, an absent extensor carpi radialis reflex and moderate atrophy of the carpal flexors. Spontaneous electromyographic activity consistent with denervation was recorded in the carpal extensor and flexor muscles. Surgical exploration of the distal radial nerve disclosed a region of fibrosis enmeshing the deep branch of the radial nerve. Following relief of the entrapped nerve, carpal hyperflexion, muscle atrophy and the extensor carpi radialis reflex deficit gradually resolved over four months. It is suggested that, In the rapidly growing limb, myoneural dysfunction Induced by trauma was the underlying pathophysiological mechanism for carpal hyperflexion. 相似文献
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A modified version of the model Opus was applied to measurements of soil water dynamics and atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) persistence in a Bruntwood silt loam soil (Haplic Andosol, FAO system) in Hamilton, New Zealand. The modified model, Opus2, is briefly described and parameter estimation for the simulations is discussed. Soil water dynamics were more accurately described by applying measured soil hydraulic properties than by estimating them using pedotransfer functions. A parameter sensitivity analysis revealed that degradation was the most relevant process in simulating pesticide behaviour by Opus2. The Arrhenius equation incorporated in Opus2 did not correctly describe the effect of temperature on degradation rates obtained at 10, 20 and 30 degrees C. However, as the Arrhenius coefficient is a very sensitive parameter and soil temperature variation was relatively narrow in the field, the Arrhenius coefficient was approximated from the laboratory study. The simulation results obtained were superior to modelling at constant temperature. Field measured persistence of atrazine in the topsoil was underpredicted using the half-life determined in the laboratory at 10 degrees C. Modelling with a lag phase followed by accelerated degradation by use of a sigmoidal degradation equation in Opus2 significantly improved the modelling results. Nevertheless, degradation processes in the laboratory under controlled conditions did not accurately represent field dissipation, however well the laboratory degradation data could be described by simple kinetic equations. The study indicates the importance of improving field techniques for measuring degradation, and developing laboratory protocols that yield degradation data that are more representative of pesticide dynamics in field soils. 相似文献
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Wikse SE McGrann JM Herd DB Falconer LL Holland PS Abello FJ Rogers GM Richardson DC Yoder DR Ramachandran S 《Journal of the American Veterinary Medical Association》2004,225(2):210-220
OBJECTIVE: To determine whether beef herds could increase profitability by reducing production cost per 100 lb (hundredweight [CWTI; ie, 45.4 kg) of calf through implementation of advice from teams of veterinarians and county extension agents supported by university specialists. DESIGN: Longitudinal study. SAMPLE POPULATION: 6 commercial cow-calf herds comprising 1,927 cows. PROCEDURE: Teams of veterinarians and county extension agents provided advice on 25 profitable ranch management practices to herd owners for 3 years. Use of each practice in herds was measured on a scale of 1 to 5 for baseline year 1999. Similar measurements were made at the end of each year for comparison with baseline values. Outcomes were measured by standardized performance analysis. RESULTS: Mean weaning weight of calves per exposed cow of the 6 herds increased significantly from 1999 (2000, 26.8 kg [59 lb; 17%]; 2001, 49.1 kg [108 lb; 31%]; and 2002, 43.2 kg [95 lb; 27%]). Mean cost per CWT of calf decreased significantly from the 1999 value (2000, -$20.04 [-18%]; 2001, -$33.40 [-29%]; and 2002, -$22.52 [-20%]). Additional profits for the 6 herds were $54,407 in 2000, $135,695 in 2001, and $116,089 in 2002 (3-year total of $306,191). Mean increase in management score of herds was positively correlated with increase in net income and accounted for > 60% of increased profits. CONCLUSIONS AND CLINICAL RELEVANCE: Profitability of beef cow-calf operations can be substantially increased through a team approach by identifying opportunities for improvements in management and helping ranch managers implement profitable practices. 相似文献
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Kronfeld DS Holland JL Rich GA Meacham TN Fontenot JP Sklan DJ Harris PA 《Journal of animal science》2004,82(6):1773-1780
The digestibility of ether extract varies greatly from forages to grains and further to added fats consisting mainly of triglycerides. This variation has been attributed to two main factors, the presence of nonhydrolyzable substances in the ether extract, especially in leafy foods, and the dilution of endogenous fecal fat. A compilation of results from 188 equine digestion balance observations on five basal feeds and 18 test feeds with added fats demonstrated a true digestibility of fat approaching 100% and an endogenous fecal fat of 0.22 g x d(-1) x kg BW(-1). The results revealed that nonhydrolyzable ether extract and endogenous fecal fat were insufficient to account for the difference between true digestibility and apparent digestibilities of ether extract in basal feeds and partial digestibilities of added fats in test feeds. A third possible contributing factor was demonstrated: an increasing first-order relationship between observed digestibilities (D, %) and the fat content of the feed (F, g/kg): D = 92.0 - 92.0e(-F/342). r2 = 0.81, P < 0.001. This equation indicates that 46% digestibility (half maximum) occurs at an ether extract or fat content of 24 g/kg, which is common in forages. It is consistent with fat digestibility or efficiency of absorption being a function of the rate of lipolysis, especially when residence time in the small intestine is limited. Consequently, we suggest that the kinetics of lipases, which are difficult to measure, may contribute to low digestibility when substrate concentration in the small intestine is low due to a low fat content in food. The status of vitamins A and E might be affected by low dietary fat contents and might be improved by fat supplementation. 相似文献
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