Evolution of meanders with hyperconcentrated flow in the loess areas

依据中国黄土分布区多沙曲流的水沙资料、河床平面形态和河床大断面测量资料分析认为: 多沙河流来水变率影响河床断面形态和曲流发育; 由于窄深的河槽是高含沙水流输沙的必要条件和结果, 因此随着含沙量的增加, 多沙河流河床断面形态首先出现变窄深的趋势, 随着含沙量的进一步增加, 水流造床能力增大, 河槽会向宽浅方向调整; 一定的河床冲淤强度有利于曲流的发育, 随着含沙量的增加, 多沙河流河床曲率存在先增加后减小的规律。In the loess areas, especially on the Loess Plateau in China, most of the rivers discharging hyperconcentrated flows have developed a typical meandering pattern. Based on the data of thirteen meandering rivers on the Loess Plateau and the Yangchangzi River, the properties of water flow and sediment load of these rivers, the effects of variations of flow and sediment load on channel cross sectional geometry and sinuosity, are analyzed in the paper. The data include the daily flow and sediment load and the geometry of channel cross sections recorded from 1976 to 1980 as well as the plan of channel measured on the landscape maps with a scale of 1 : 50 000 or 1 : 100 000. From these data we extrast parameters reflecting the characteristics of flow and sediment load, channel geometry, and sedimentation in channel and channel adjustment thereupon. Follows are the results of analyses. 1) As the rivers with low sediment concentration, the hyperconcentrated flow dominated rivers have a narrower and more sinuous channel if the fluctuation in water discharge is low. 2) With the increase of sediment concentration, the channel cross sectional geometry is usually widened in the case of the rivers with low sediment concentration. Since a narrow channel is one of the requisite conditions as well as the result of sediment transport of hyperconcentrated flows, the channels become narrow initially as the sediment concentration of hyperconcentrated flow increases. However, if the sediment concentration is larger than a certain value, the energy consumption of sediment transport is lowered down thenceforth with the increase of sediment concentration, and the flow becomes unsaturated and has a higher channel making capacity, so the channel is widened. Revealed by the instantaneous hydrological records, the transition takes place at the sediment concentration of about 400 kg/m3. 3) Both excessive and low intensity of sedimentation in the channel is unfavorable to development of meanders. In the case of the rivers with a low sediment concentration, the energy consumption per unit distance increases with the enlargement of slope and discharge and so the capacity of channel making of the flows; therefore, the channel sinuosity increases initially and decreases later. Regarding the hyperconcentrated flow dominated rivers, the energy consumption of sediment transport is lowered and the channel making capacity as well as magnitude of sedimentation are enlarged accompanying with the increase of sediment concentration, so an initial increase of channel sinuosity is followed by a decrease also. Due to the difference of the mechanism of channel sinuosity adjustment from that of cross section changes, the existence of the asychronism in the adjustment of the two factors is reasonable.published_or_final_versio

Wide-bandgap high- k Y2 O3 as passivating interlayer for enhancing the electrical properties and high-field reliability of n-Ge metal-oxide-semiconductor capacitors with high- k HfTiO gate dielectric

High- k and wide-bandgap Y2 O3 was proposed as an interlayer in n-Ge metal-oxide-semiconductor (MOS) capacitor with HfTiO gate dielectric for passivating its dielectric/Ge interface, and thus improving its electrical properties and high-field reliability. Results showed that as compared to the Ge MOS capacitor with HfTiO dielectric, the sample with HfTiO/ Y2 O3 dielectric had better electrical properties such as higher dielectric constant (k=24.4), lower interface-state density, and less frequency-dependent C-V dispersion, and also better reliability with less increases in gate leakage and interface states after high-field stressing. This should be attributed to the excellent interfacial quality of Y2 O3 /Ge with no appreciable growth of unstable GeOx at the interface as confirmed by transmission electron microscopy. Moreover, Y 2 O3 can also act as a barrier against the diffusions of Ge, Hf, and Ti, thus further improving the interface quality. © 2009 American Institute of Physics.published_or_final_versio

Prospective evaluation of low-dose ketoconazole plus hydrocortisone in docetaxel pre-treated castration-resistant prostate cancer patients.

BackgroundKetoconazole is a well-known CYP17-targeted systemic treatment for castration-resistant prostate cancer (CRPC). However, most of the published data has been in the pre-chemotherapy setting; its efficacy in the post-chemotherapy setting has not been as widely described. Chemotherapy-naïve patients treated with attenuated doses of ketoconazole (200-300 mg three times daily) had PSA response rate (>50% decline) of 21-62%. We hypothesized that low-dose ketoconazole would likewise possess efficacy and tolerability in the CRPC post-chemotherapy state.MethodsMen with CRPC and performance status 0-3, adequate organ function and who had received prior docetaxel were treated with low-dose ketoconazole (200 mg orally three times daily) and hydrocortisone (20 mg PO qAM and 10 mg PO qPM) until disease progression. Primary endpoint was PSA response rate (>50% reduction from baseline) where a rate of 25% was to be considered promising for further study (versus a null rate of <5%); 25 patients were required. Secondary endpoints included PSA response >30% from baseline, progression-free survival (PFS), duration of stable disease and evaluation of adverse events (AEs).ResultsThirty patients were accrued with median age of 72 years (range 55-86) and median pre-treatment PSA of 73 ng ml(-1) (range 7-11,420). Twenty-nine patients were evaluable for response and toxicity. PSA response (>50% reduction) was seen in 48% of patients; PSA response (>30% reduction) was seen in 59%. Median PFS was 138 days; median duration of stable disease was 123 days. Twelve patients experienced grade 3 or 4 AEs. Of the 17 grade 3 AEs, only 3 were attributed to treatment. None of the two grade 4 AEs were considered related to treatment.ConclusionsIn docetaxel pre-treated CRPC patients, low-dose ketoconazole and hydrocortisone is a well-tolerated, relatively inexpensive and clinically active treatment option. PSA response to low-dose ketoconazole appears historically comparable to that of abiraterone in this patient context. A prospective, randomized study of available post-chemotherapy options is warranted to assess comparative efficacy

Perceived beneficiaries and support for the globalization of higher education: a survey experiment on attitudes toward international students

Foreign students are one of the most significant immigrant categories in many North American and Western European countries. Yet, as their numbers have swelled, many governments have experienced increasing pressures to cap their entry. This is true despite the sizable benefits that foreign students bring to host countries, and despite standard political economy concerns about immigrants—that they take away jobs or abuse public entitlements—not applying to foreign students. We field a nationally-representative survey experiment in the UK, one of the top destinations for foreign students, to examine potential activators of public support for capping the number of foreign students. Results show that support for caps is most activated when citizens are primed to think about foreign students competing with domestic students for scarce admissions slots at universities

The Effectiveness of a Geriatric Hip Fracture Clinical Pathway in Reducing Hospital and Rehabilitation Length of Stay and Improving Short-Term Mortality Rates

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Selective upper endoscopy for foreign body ingestion in children: an evaluation of management protocol after 282 cases

Purpose: Foreign body ingestion is a common problem in both children and adults. This study aims to evaluate a management protocol where endoscopic examination was only selectively used after routine direct laryngoscopy to minimize patient discomfort and the need for general anesthesia in children. Method: A management protocol for foreign body ingestion based on symptoms was introduced in 1998 and records of children admitted to a university-affiliated hospital between January 1999 and October 2005 with suspected foreign body ingestion were evaluated. Symptoms, radiologic and endoscopic findings, and outcome were reviewed. Results: A total of 282 patients were admitted. The mean age of patients was 5.75 years (range, 9 months to 17 years). There were 167 boys and 115 girls. Based on our protocol, 84 (29.8%) patients required an upper endoscopy. Fish bones were most commonly involved (68.8%). Foreign bodies, which were either removed or dislodged, were found during upper endoscopy in only 25 (8.8%) patients overall. All patients had an uneventful outcome. No complications or mortalities were encountered. There were no readmissions for those who did not undergo endoscopic examination. Conclusion: It is safe to selectively perform upper endoscopy depending on symptoms when managing children with foreign body ingestion. © 2006 Elsevier Inc. All rights reserved.postprin

Assessment of postoperative short-term and long-term mortality risk in Chinese geriatric patients for hip fracture using the Charlson comorbidity score

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A semi-discrete model and its approach to a solution for a wide moving jam in traffic flow

This paper investigates the analytical and numerical solutions to wide moving jams in traffic flow. Under the framework of the Lagrange coordinates, a semi-discrete model and a continuum model correlate with each other, in which the former model approaches the latter as the increment ΔM in the former model vanishes. This implies that the solution to a wide moving jam in the latter model, which can be analytically derived using the known theory, can be conceivably taken as an approximation to that of the former model. These results were verified through numerical simulations. Because a detailed understanding of the traffic phase "wide moving jam" is very important for the further development of Kerner's three-phase traffic theory, this study helps to explain the empirical features of traffic breakdown and resulting congested traffic patterns that are observed in real traffic. © 2011 Elsevier B.V. All rights reserved.postprin

An agent-based negotiation model to support partner selection in a virtual enterprise

Session - MP-Fd Supply Chain Management & Logistics 4: cie182hk-1Conference Theme: Soft Computing Techniques for Advanced Manufacturing and Service SystemsIn response to the global business competitive environment, it is common for several companies to participate in a virtual enterprise (VE) to cooperate and collaborate dynamically to complete a common business opportunity. This paper proposes an agent-based negotiation model to support the partner selection process in a VE. To begin with, the VE partner selection problem is abstracted as a buyer-seller relationship such that the VE initiator is the buyer and the VE partners are sellers or vice verse. In the multi-agent system (MAS) that supports the proposed negotiation model, autonomous agents are established to represent various parties and functions of the VE. For instance, a buyer agent represents the VE initiator and the potential partners are represented by seller agents. Thus, the VE partner evaluation and selection problem is the process of finding the partners that are able to provide the buyer with the right quality products and services at the right price and at the right time. Evaluation and selection of partners is a typical multiattribute decision making (MADM) problem involving various issues that can both be qualitative and quantitative.published_or_final_versionThe 40th International Conference on Computers & Industrial Engineering (CIE40), Awaji City, Japan, 25-28 July 2010. In Proceedings of the International Conference on Computers and Industrial Engineering, 2010, p. 1-