浅层软土路基处理方案研究

根据实际案例,分析浅层软土的特点,给出不同的路基处理方案比选,最终得出最优的处理方案.     

On efficiency of the ratio estimator

Summary The exact mean square error for the ratio estimator of a finite population total based on simple random sampling without replacement is shown to have an expected value less than that of the variance of the ratio estimator based on Midzuno’s scheme, under a usual super-population model.     

The economic value of INTUITY in aortic valve replacement

Objective: The recent development of the EDWARDS INTUITY Elite? (EIE) valve system enables the rapid deployment of a prosthetic surgical heart valve in an aortic valve replacement (AVR) procedure via both the minimally invasive (MISAVR) and conventional (CAVR) approaches. In order to understand its economic value, this study performed a cost evaluation of the EIE valve system used in a MIS rapid-deployment approach (MIS-RDAVR) vs MISAVR and CAVR, respectively, compared to standard prosthetic aortic valves.

Methods: A simulation model was developed using TreeAge (and validated with MS Excel) to compare the inpatient utilization and complication costs for each treatment arm. Thirty-day clinical end-points for the MIS-RDAVR (mortality and complications) were taken from the TRANSFORM trial; and a best evidence review of the published literature was used for the MISAVR and CAVR approaches. Studies were pooled and parameter estimates were weighted by sample size in order to compare the TRANSFORM patients. Cost data (2016 USD) were taken from the Premier database. Incremental cost and cost-effectiveness was assessed and one-way/probabilistic sensitivity analyses performed to gauge the robustness of the results.

Results: MIS-RDAVR costs $2,621 less than CAVR and had lower mortality rates, making it a superior (dominant) technology relative to CAVR. MIS-RDAVR costs $4,560 more than MISAVR, but was associated with an additional 0.20 life years-per-patient. This implies a cost-effectiveness ratio of $22,903 per-life-year-gained. Thus, MIS-RDAVR is cost-effective compared to MISAVR.

Conclusions: The EIE valve system deployed in a MIS approach appears to be a cost-effective technology compared to MISAVR and CAVR. When compared to CAVR it may achieve cost savings as well. These results suggest that MIS-RDAVR confers superior economic value compared to both standard MISAVR and CAVR via lowered key complication rates (re-operation, renal complications, wound infection, TIA, endocarditis) and utilization (cross-clamp time, hospital ward days).     

Comparing post-operative resource consumption following transcatheter aortic valve implantation (TAVI) and conventional aortic valve replacement in the UK

Objective:

To define the in-hospital and 6-month post-discharge resource use, following Transcatheter Aortic Valve Implantation (TAVI) and conventional Aortic Valve Replacement (AVR) surgery within a single UK hospital.

Methods:

A local service evaluation of patients undergoing TAVI or AVR between January 2011 and May 2012 captured data until 6-months post-procedure, collected from hospital records and via a General Practitioner questionnaire. The main end-points were mortality, time in ITU/HDU, hospital length of stay (LoS), discharge destination, re-admission, and post-discharge primary/secondary care resource use. Sub-group analyses were performed for AVR patients aged ≥80 (AVR?≥?80) and with EuroSCORE of ≥10 (AVR ES?≥?10) to allow more direct comparison with ‘TAVI type’ patients.

Results:

Results are given as means (standard deviation) for TAVI (n?=?51), AVR (n?=?188), AVR?≥?80 (n?=?48), and AVR ES?≥?10 (n?=?47), respectively, unless otherwise stated. Age in years was 83.0 (8.1), 71.2 (13.1), 84.1 (2.7), 79.4 (7.1); EuroSCORE was 24.7 (11.9), 8.1 (6.4), 12.0 (6.0), and 16.5 (6.6); post-operative LoS (days) was 11.5 (11.2), 10.9 (10.8), 14.3 (16.7), and 15.2 (17.7). For discharged patients, 0%, 7%, 13%, and 9% had unplanned cardiac-related re-admissions within 30-days of discharge. Time to first readmission was 74.6 (34.0), 35.0 (34.2), 20.8 (9.7), and 22.6 (14.3) days.

Limitations:

This was a single-center retrospective evaluation, not prospectively powered to confirm differences in outcomes.

Conclusions:

Despite TAVI being performed in an older, higher risk population, LoS was similar to AVR. Most strikingly there were no cardiac-related re-admissions within 30-days for TAVI and time to first re-admission was significantly longer. This evaluation suggests that TAVI is clinically appropriate and provides economic advantages in both the hospital and post-discharge setting in this high risk group. Many patients undergoing TAVI are considered unfit for surgery and, hence, TAVI offers a treatment that delivers similar results to traditional AVR without the high risk associated with surgery.     

宅基地退出政策对农户迁入社区韧性的影响 ——以四川省邛崃市宅基地异地置换模式为例

研究目的：基于实地调研的农户微观数据,以四川省邛崃市宅基地异地置换模式为例,明确宅基地退出政策对社区韧性的影响及作用机制,以深化农村宅基地制度改革和提高社区治理水平。研究方法：PSM-DID模型。研究结果：（1）宅基地退出政策对社区韧性存在正向政策影响,其中,宅基地退出政策对社区倡导力和社区能动力有显著促进作用,但对社区包容力有显著抑制作用;（2）社区生态环境水平、多元主体治理参与水平和社区基础设施水平在宅基地退出政策与社区韧性之间起正向推动的中介作用;（3）社区韧性水平的高低受社区倡导力影响最大,其次是社区包容力,最后是社区能动力。研究结论：实施宅基地退出政策有助于农户迁入社区恢复稳定,这对于提升社区治理水平,实现乡村振兴战略具有重要实践意义。     

Supervisor Support for the Permanent Replacement of Economic Strikers

Sixty-one supervisors were surveyed to examine the importance of organization commitment, union approval, and quality of union-management relationship in explaining supervisor support for hiring permanent replacements in short and long strike situations. Organization commitment and union approval exhibited a unique negative relationship with support for hiring replacements in a short strike, and union approval exhibited a unique negative relationship with support for hiring replacements in a long strike situation.     

Price determinants of bred heifers: Do reputations matter?

Replacement brood cows are among the most significant investments for cow-calf operations, thus crucial to profitability. Many cow-calf producers find it cost effective to purchase replacements from a reliable replacement heifer seller, though by doing so they increase risk of reproductive inefficiency due to unknown characteristics of the heifers. When important information about a product is missing to buyers, a seller can build a reputation over time that acts as signal for quality. Previous work has explored reputation effects in feeder cattle markets, but to our knowledge we are the first to explore reputation effects in bred replacement cattle markets. Using data from an annual replacement heifer sale, we analyze the values of heifer characteristics and test for premiums from reputation development. After controlling for reproductive practices, breed, and other characteristics, we find reputation does not play the role that Shapiro theorized. In this sale, the lot order is strategically chosen and may indicate bred heifer quality to buyers, replacing the need for reputation as a signal. This study highlights the importance of quality signals and regional preferences in bred replacement cattle marketing and lays the empirical groundwork for future studies to test Shapiro's theory.     

利益集团、行为偏好与黄宗羲定律——中国封建王朝更替动因的经济学分析

中国封建社会特殊的社会结构下,封建王朝在其演进过程中,农民集团和官僚集团之间的利益博弈对税赋改革的影响会导致＂黄宗羲定律＂的形成。税赋愈改愈重使得农民在当朝所能获得的效用随时间的推移而降低,从而导致农民预期起义成本的降低,当这种预期成本下降到一定水平后,农民集团会采取有效的集团行动并转向对新的政治体制的寻求,最终完成朝代的更替。这一过程可以运用经济学的基本理论,并建立适当模型,从而对中国社会特有的王朝更替现象进行解释。     

ADOPTION AND PRODUCTIVITY IMPACT OF MODERN RICE VARIETIES IN BANGLADESH

Technological progress has helped Bangladesh to achieve self‐sufficiency in rice production in 2001 from a heavy import‐dependence, despite doubling of population and a reduction in arable land since its independence in 1971. As the adoption of modern varieties (MV) of rice is reaching a plateau, particularly for the irrigated ecosystem, an important issue is whether the research system will be able to sustain the growth of production. The present paper addresses the following questions: (i) to what extent farmers have been replacing the old MV with the new MV, and (ii) what has been the impact of the variety replacement on productivity and profitability. How crucial is the continuous research and release of improved rice varieties toward improving farm production and income for farmers comes out as a clear message to policymakers from the current paper.