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981.
982.
983.
This study compares the instrumentation and analysis techniques used when determining the power expended pedalling a rope-braked
ergometer manufactured by Monark (Sweden) during a low intensity test. Power values were generated by eight subjects. The
instrumentation consisted of load cells to measure the rope brake forces, a tachometer to measure the flywheel velocity and
instrumented pedal cranks manufactured by Schoberer Rad Messtechnik (SRM). The subjects pedalled a rope-braked ergometer at
60 rev min-1, against a resistance of 3 kg, for 5 minutes. Three different measurements of the mean power were recorded and these were
compared with the value given by Monark. The SRM cranks provided two sets of results using different software packages supplied
with the cranks. SRM standard software is used for taking measurements during training and cycle races over long time periods.
An additional piece of software is provided by SRM called Ptnew, which gives readings of torque and pedal cadence over periods
up to 30 seconds. Using the values supplied by Monark each subject generated 180 W of power. The mean power for the eight
subjects, measured using the SRM cranks, was 170.36 W (SD 4.11) using the alternative SRM software (Ptnew) over a 30 second
period and 173.68 W (SD 2.21) using the standard SRM software. From the direct measurement of the brake forces and flywheel
velocity the mean power across the eight subjects was 148.90 W (SD 5.89). The SRM cranks measure the input power, whereas
the direct measurement system measures the power output excluding mechanical losses. These values give a figure for the mechanical
efficiency for the roped-braked ergometer of 88%. It was found that Monark overestimates the power generated by the subjects
when compared with both the SRM systems and the direct measurement instrumentation. 相似文献
984.
985.
Contingent Valuation and Cultural Resources: A Meta-Analytic Review of the Literature 总被引:4,自引:0,他引:4
Douglas S. Noonan 《Journal of Cultural Economics》2003,27(3-4):159-176
Contingent valuation methodology (CVM) has been increasingly applied to cultural resources. CVM employs survey methods to gather stated preference information, which can be used to estimate economic values of various cultural resources and projects. Although popular in other fields, the application of CVM in the cultural arena is relatively recent. This article summarizes this growing body of empirical literature and its range of findings. A meta-analysis gives a statistical view of the ``state of the art' of the literature. This preliminary analysis sheds light on the consistency and validity of the use of this method in cultural applications. 相似文献
986.
Wendy S. Zabava Ford 《Journal of Applied Communication Research》2003,31(3):189-211
This study examined customers' perceptions of personalized service communication performance in relation to their expectations as predictors of their satisfaction and loyalty intentions in four professional service contexts. Survey data were obtained from 253 customers regarding their expectations and experiences with physicians, dentists, auto mechanics, or hairdressers. Multisample covariance structure analysis procedures were performed to assess the level of support for alternative theoretical models across all four professional contexts. Results provided support for one model, specifying that customers' perceptions of communication performance accounted for significant variation in customer satisfaction, which, in turn, predicted customers' loyal behavioral intentions. Customers' expectations did not play an influential role in predicting customer satisfaction and loyalty, as proposed in an alternative model 相似文献
987.
988.
S. Mahadevan 《Resonance》2007,12(1):15-22
For a scientist, making a seminal contribution even in one area of science is a matter of joy and pride. To be able to start
several fields and contribute significantly to all of them is indeed a rare feat. Louis Pasteur belongs to this rare breed
of scientists. He was a chemist, microbiologist, immunologist, and biotechnologist, all rolled into one. He founded the field
of stereochemistry, established the foundations of modern microbiology, disproved the theory of spontaneous generation, demonstrated
the microbial basis of fermentation, and derived vaccines against several bacterial and viral diseases. His contributions
to human welfare in one life-time are more than what others can aspire to make over many lifetimes. His approach, based on
logic and reason, helped to shape the modern scientific outlook. 相似文献
989.
This study analyzes the search behavior of end users who had taken a class in searching MEDLINE on the National Library of Medicine's MEDLARS system. Of the class alumni, 58% obtained passwords. Most of these were still conducting their own searches twelve to eighteen months later. Telephone interviews and search observations indicated that these end users were satisfied with their results and felt they had mastered the basic mechanics of searching. However, appropriate use of explodes and subheadings, as well as locating appropriate search terms, still presented difficulties for them. Further training in these areas may be required. 相似文献
990.