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61.
Peter Simmons 《Language Resources and Evaluation》1968,2(3):101-113
Despite its concentration on technical developments in library science, this survey is offered here because it is relevant
to humanists for two reasons: first, that humanists all use libraries and therefore need to encourage their evolution to higher
levels of efficiency, and, second, that the procedures outlined here may be of help to humanists in establishing procedures
for their own research. 相似文献
62.
63.
In Exp. I, 81 male psychiatric patients were divided into 9 subgroups according to age and length of hospitalization. Plural nouns were reinforced by positive verbal feedback. Results were: (1) least chronic Ss increased their operant rates; (2) most chronic Ss did not; and (3) there was significant interaction with respect to age and chronicity. In Exp. II, 60 schizophrenics were divided into 6 subgroups with respect to length of hospitalization and mode of reinforcement, i.e., verbal, primary, or combination. Acute-type schizophrenics responded positively to all types of reinforcement. Chronics responded only to primary reinforcement and to the combination procedure. Mode of reinforcement was a significant variable affecting operant rate. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Rat endometrial Vdup1 expression: changes related to sensitization for the decidual cell reaction and hormonal control 总被引:4,自引:0,他引:4
To study the effect of re-immunization against inhibin on ovarian response and hormonal profiles, Japanese beef heifers (n = 5) were re-immunized three times with inhibin vaccine (recombinant ovine inhibin alpha-subunit in oil emulsion, 125 microg ml(-1)) one year after the primary immunization. Control heifers (n = 5) were injected with placebo (Montanide: Marcol adjuvant alone). Oestrous cycles were synchronized by using prostaglandin F2alpha (PGF2alpha) and ovarian response was monitored daily by ultrasonography. Blood samples were collected by jugular venipuncture for assessment of hormonal levels and inhibin antibody titres. In contrast to controls, inhibin re-immunized heifers generated antibodies against inhibin rapidly reaching a peak level 9 days after the first booster injection. The mean concentrations of FSH in re-immunized cows increased significantly in comparison with controls. In addition, there was a significant increase in oestradiol-17beta and progesterone levels in re-immunized cows compared with controls. Inhibin re-immunized heifers had a significant increase in small (> or =4 < 7 mm), medium (> or =7 < 10 mm) and large (> or =10 mm in diameter) sized follicles. Moreover, the mean ovulation rate was 5.0 +/- 1.1 after the third booster injection in re-immunized heifers compared with control heifers (single ovulation). These results clearly demonstrate that re-immunization of inhibin can be used to enhance ovarian follicular development and ovulation rate. Furthermore, the great number of follicles is a potential source of oocytes that could be harvested for in vitro fertilization and embryo transfer programmes. 相似文献
65.
Roger W. Elliott Miner P. Marchbanks Michael G. McWilliams Larry J. Ringer D.B. Simmons 《Computers & Industrial Engineering》1978,2(3):141-151
Under certain conditions, traditional hypothesis-testing techniques may be used as a management tool by software developers or software purchasers who wish to insure that their packages have some specified reliability level. These conditions are: (1) the existence of independent collections of test data, (2) a way of determining the correctness of processing of these collections, and (3) a way of randomly selecting test data.Two basic approaches have been described. In a fixed sample size test, the user decides on the reliability desired. He can then determine the number of test cases which must be examined and the acceptance/rejection criteria. In a sequential test, the desired reliability level is again pre-determined, but samples are tested one at a time until an accept/reject decision can be made.Experiments with a large amount of error data derived from six separate systems indicate that reliability results derived from these models are consistent with actual reliability figures.Most current acceptance procedures are based on a naive assumption that a large program can be exhaustively tested and delivered in an error-free condition. Because these expectations cannot be fulfilled, the manager of a software development project or the purchaser of a software product is provided with no quantitative information on which to base an acceptance decision and is thus forced to make these decisions based mostly on intuition and his own experience in similar situations. These models allow one to replace these intuition-based decisions with quantitatively-based decisions and thus constitute an important contribution to the science of management of software development efforts. 相似文献
66.
67.
S. M. Wiederhorn S. W. Freiman E. R. Fuller Jr C. J. Simmons 《Journal of Materials Science》1982,17(12):3460-3478
Effects of water and a variety of organic liquids on crack-growth rates in soda-lime-silica glass was investigated. When water is present in organic liquids, it is usually the principal agent that promotes subcritical crack growth in glass. In region I, subcritical crack growth is controlled primarily by the chemical potential of the water in the liquid; whereas in region II, crack growth is controlled by the concentration of water and the viscosity of the solution formed by the water and the organic liquid. In region III, where water does not affect crack growth, the slope of the crack-growth curves can be correlated with the dielectric constant of the liquid. It is suggested that these latter results can be explained by electrostatic interactions between the environment and charges that form during the rupture of Si-O bonds. 相似文献
68.
69.
Role of soil freezing events in interannual patterns of stream chemistry at the Hubbard Brook Experimental Forest,New Hampshire 总被引:1,自引:0,他引:1
Fitzhugh RD Likens GE Driscoll CT Mitchell MJ Groffman PM Fahey TJ Hardy JP 《Environmental science & technology》2003,37(8):1575-1580
Soil freezing is a disturbance of the below ground environment, potentially resulting in increased losses of NO3- and surface water acidification. Here, we report the effects of soil freezing on interannual variation in stream chemistry at the Hubbard Brook Experimental Forest, New Hampshire. Data from 1970 to 1997 of soil frost depth, snow cover, precipitation, air temperature, and stream discharge and chemistry were used in a stepwise linear regression model to select the variables that best predicted deviations of annual stream concentrations from 4-year running averages. Variables quantifying soil freezing severity were selected as significant predictors of short-term fluctuations in stream K+, NO3-, Ca2+, and Mg2+ concentrations from 1970 to 1989, explaining 59 and 47% of the short-term variability in K+ and NO3-, respectively. Fine-root mortality and disturbance of root-soil-microbe interactions, with subsequent effects on decomposition and nutrient uptake, likely contributed to the mobilization of K+ and NO3- to streamwater following severe soil freezing events. The relationship between soil freezing and stream chemistry, however, weakened during the period 1990-1997. Because soil freezing has had inconsistent effects on stream chemistry during the period 1970-1997, it is unclear whether future changes in the frequency, duration, and depth of soil freezing events as the result of changes in the snow cover regime under a warmer climate will have significant impacts on the losses of NO3- and nutrient-base cations from temperate northern ecosystems. 相似文献
70.
Orchard J Greif C Golub GH Bjornson B Atkins MS 《IEEE transactions on medical imaging》2003,22(11):1427-1435
Registration using the least-squares cost function is sensitive to the intensity fluctuations caused by the blood oxygen level dependent (BOLD) signal in functional MRI (fMRI) experiments, resulting in stimulus-correlated motion errors. These errors are severe enough to cause false-positive clusters in the activation maps of datasets acquired from 3T scanners. This paper presents a new approach to resolving the coupling between registration and activation. Instead of treating the two problems as individual steps in a sequence, they are combined into a single least-squares problem and are solved simultaneously. Robustness tests on a variety of simulated three-dimensional EPI datasets show that the stimulus-correlated motion errors are removed, resulting in a substantial decrease in false-positive and false-negative activation rates. The new method is also shown to decorrelate the motion estimates from the stimulus by testing it on different in vivo fMRI datasets acquired from two different 3T scanners. 相似文献