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991.
Strahle A Stainton MC 《Women and birth : journal of the Australian College of Midwives》2006,19(1):17-21
Comments of women engaged in a longitudinal study of urinary leaking from first trimester to 12 months following birth provide the data for this paper. Useful insights into the factors contributing to the maintenance of silence and ways to break the barriers to discussion of urinary incontinence before, during and following pregnancy were revealed. Given the prevalence of 30% of Australian women experiencing urinary leaking following pregnancy, it is imperative that midwives engage in discussion and support prevention of this unwelcome outcome of childbirth. 相似文献
992.
This paper describes a simulation experiment to evaluate the relative effectiveness of rescheduling policies in capacity-constrained, just-in-time (JIT) make-to-stock production environments. Three performance measures were analyzed: average finished goods inventory, total units of sales lost, and a measure of schedule instability. Among the three loading methods we studied (level loading, front loading, and back loading), none was superior across all three performance measures. Level loading was the most robust, while back loading had an interaction effect with forecasting model and capacity level. Time fence scenario was found not to be as significant a factor in system performance as reported by previous research. Once an acceptable time fence scenario is selected, attempts to optimize this factor do not appear to offer significant improvement. It was found that higher demand variation, larger forecast errors, and tight capacity lead to the degradation of system performance. Judicious use of slack capacity helps a system to incorporate the periodic schedule changes typical of JIT systems. 相似文献
993.
Michael L. Gargas Robin L. Norton Mark A. Harris Dennis J. Paustenbach Brent L. Finley 《Risk analysis》1994,14(6):1019-1024
Biomonitoring programs for urinary chromium (Cr) typically attempt to evaluate occupational exposure via the inhalation route. This study investigated whether Cr can be detected in the urine of people following the ingestion of soils that contain relatively high concentrations of chromium in chromite ore processing residue (COPR). To evaluate the reasonableness of using urinary monitoring to assess environmental exposure, six volunteers ingested 400 mg of soil/day (low-dose group), two others ingested 2.0 g of soil/day (high-dose group) for 3 consecutive days, and one person ingested a placebo on each of 3 days. The soil and COPR mixture contained concentrations of total chromium (Cr) and hexavalent chromium [Cr(VI)] of 103 ± 20 and 9.3 ± 3.8 mg/kg, respectively. Therefore, the low-dose group ingested 41 μg Cr/day [including 3.7 μg Cr(VI)] and the high-dose group ingested 206 μg Cr/day [including 18.6 μg Cr(VI)] on each of 3 consecutive days. All urine samples were collected and analyzed individually for total Cr on the day prior to dosing, during the 3 days of dosing, and up to the first void 48 h after the last dose. No significant increases in urinary Cr excretion were found when background excretion data were compared with data following each of the 3 days of dosing or in daily mean urine concentrations of the high- vs the low-dose groups. It appears that Cr present in a soil and COPR mixture at Cr doses up to 200 μg/day is not sufficiently bioavailable for biomonitoring of urine to be informative. These results are consistent with previously published findings suggesting that incidental exposure to dusts and soils containing comparable levels of Cr will not result in increased concentrations of Cr in urine. 相似文献
994.
KAREN L. DONOHUE 《Production and Operations Management》1994,3(2):78-99
As manufacturing firms push to achieve shorter lead times and higher levels of customer service, the basic capability of underlying manufacturing processes must be reexamined. The capacity and operational variability of a process dictate a certain set of realistic performance goals. In this paper, we examine this fundamental relationship from an economic perspective using two levels of analysis. At the aggregate level, we model the manufacturing process as a single server queue and compare the traditional roles of marketing and manufacturing in setting performance and process design parameters. Insights gained at this level are incorporated into the analysis of a realistic multiserver, multistation manufacturing line. We develop an interaction decision tool to guide the selection of process and performance parameters in this more complex environment. 相似文献
995.
996.
Gerard M. Campbell 《决策科学》1992,23(2):312-331
Fixed interval scheduling is studied in the context of a rolling horizon framework that is developed by building on previous work in the master scheduling area. The rolling horizon framework includes a stationary scheduling model which uses the “time fencing’concept by partitioning the planning horizon into three sections. The lengths of these sections and the frequency at which the stationary problem is updated and resolved are discussed as parameters of the rolling horizon model. Two different interpretations of the freeze interval parameter are examined, enabling confirmation and clarification of results presented in an earlier study. Details are given for three methods of calculating safety stocks as a function of rolling horizon parameters, including a method which results in optimal safety stock levels. A comparison of the safety stock methods shows that the constant safety stock method can result in inventories that are significantly above optimal under certain conditions, whereas the constant service level method consistently yields nearly optimal results. 相似文献
997.
Auditors' assessment of management's dispositions presumably affects their subsequent judgments. However, little is known about the process by which auditors infer characteristics of management. This paper proposes the theory of correspondent inferences [25] as a framework for examining auditors' assessment of management's dispositions; the model is tested in a laboratory experiment using experienced audit managers. The results are consistent with the proposed theoretical framework. Implications for future research are discussed. 相似文献
998.
Marketing communication intensity (i.e., the ratio of advertising and promotional expenditures to sales) has been an important topic for both business managers and academics. Here, we investigate cross-sectional and time-series variation of communication intensity due to: type of offering (product versus service) and type of market (consumer versus industrial). Overall, we find that both of these factors affect variation of communication intensity across industries and over time. However, the effect of market type is much more dramatic than the effect of offering type. Such knowledge about patterns in communication intensity levels helps managers make decisions about how much to spend on advertising and promotion. 相似文献
999.
CLAYTON M. CHRISTENSEN 《Production and Operations Management》1992,1(4):334-357
The technology S-curve is a useful framework describing the substitution of new for old technologies at the industry level. In this paper I use information from the technological history of the disk drive industry to examine the usefulness of the S-curve framework for managers at the firm level in planning for new technology development. Because improvements in over-all disk drive product performance result from the interaction of improved component technologies and new architectural technologies, each of these must be monitored and managed. This paper focuses on component technology S-curves, and a subsequent paper, also published in this issue of the journal, examines architectural technology Scurves. Improvement in individual components followed S-curve patterns, but I show that the flattening of S-curves is a firm-specific, rather than uniform industry phenomenon. Lack of progress in conventional technologies may be the result, rather than the stimulus, of a forecast that the conventional technology is maturing, and some firms demonstrated the ability to wring far greater levels of performance from existing component technologies than other firms. Attacking entrant firms evidenced a distinct disadvantage versus incumbent firms in developing and using new component technologies. Firms pursuing aggressive Scurve switching strategies in component technology development gained no strategic advantage over firms whose strategies focused on extending the life of established component technologies. 相似文献
1000.
高等院校闲置、报废仪器设备管理办法探讨 总被引:1,自引:0,他引:1
吕洪军 《河北科技大学学报(社会科学版)》2006,6(1):37-38,12
本文就如何最大限度地回收高校闲置和报废仪器设备,提高国有资产的使用效益,更好地为教学科研服务进行了探讨,提出运用经济杠杆原理、引进激励机制、进行二次调剂、设备资源、开通流通渠道等办法处理闲置、报废仪器设备。 相似文献