An analytic approach to better understanding and management of coronary surgeries

Demand for high-quality, affordable healthcare services increasing with the aging population in the US. In order to cope with this situation, decision makers in healthcare (managerial, administrative and/or clinical) need to be increasingly more effective and efficient at what they do. Along with expertise, information and knowledge are the other key sources for better decisions. Data mining techniques are becoming a popular tool for extracting information/knowledge hidden deep into large healthcare databases. In this study, using a large, feature-rich, nationwide inpatient databases along with four popular machine learning techniques, we developed predictive models; and using an information fusion based sensitivity analysis on these models, we explained the surgical outcome of a patient undergoing a coronary artery bypass grafting. In this study, support vector machines produced the best prediction results (87.74%) followed by decision trees and neural networks. Studies like this illustrate the fact that accurate prediction and better understanding of such complex medical interventions can potentially lead to more favorable outcomes and optimal use of limited healthcare resources.     

Uncensoring censored data for machine learning: A likelihood-based approach

Various machine learning techniques have been applied to different problems in survival analysis in the last decade. They were usually adapted to learning from censored survival data by using the information on observation time. This includes learning from parts of the data or interventions to the learning algorithms. Efficient models were established in various fields of clinical medicine and bioinformatics. In this paper, we propose a pre-processing method for adapting the censored survival data to be used with ordinary machine learning algorithms. This is done by pre-assigning censored instances a positive or negative outcome according to their features and observation time. The proposed procedure calculates the goodness of fit of each censored instance to both the distribution of positives and the spoiled distribution of negatives in the entire dataset and relabels that instance accordingly. We performed a thorough empirical testing of our method in a simulation study and on two real-world medical datasets, using the naive Bayes classifier and decision trees. When compared to one of the popular ML methods dealing with survival, our method provided good results, especially when applied to heavily censored data.     

湿热环境对辐射损伤小鼠的影响

为探讨湿热环境对辐射损伤动物的影响,将受不同剂量^60Coγ射线照射的小鼠放人自然湿热环境（HHE）及模拟HHE中,观察其对小鼠存活时间及外周血淋巴细胞计数的影响。结果表明：（1）模拟HHE暴露条件,7Gy照射,随着暴露时间的延长,小鼠的存活时间缩短,死亡率增加;9Gy照射,暴露60分钟以上,小鼠一周内全部死亡;外周血淋巴细胞和白细胞计数各组均在照后显著下降,但室温（RT）组比HHE组下降幅度小且恢复较快。（2）自然HHE暴露条件,7Gy照射,小鼠存活时间缩短,死亡率增加;9Gy照射,除HHE暴露3h外,小鼠存活时间缩短,死亡率增加。RT组小鼠外周血淋巴细胞下降速度低于各自然HHE组且有顿挫回升。所以,自然及模拟HHE环境,使受照小鼠生存指标明显下降,加重照后早期外周血淋巴细胞下降。     

Effect of p53 on lung carcinoma cells irradiated by carbon ions or X-rays

The study is to investigate the feasibility and advantages of heavy ion beams on radiotherapy. The cellular cycle and apoptosis, cell reproductive death and p53 expression evaluated with flow cytometry, clonogenic survival assays and Western blot analysis were examined in lung carcinoma cells after exposure to 89.63 MeV/u carbon ion and 6 MV X-ray irradiations, respectively. The results showed that the number colonyforming assay of A549 was higher than that of H1299 cells in two radiation groups; A549 cellular cycle was arrested in G2/M in 12 h and the per-centage of apoptosis ascended at each time point of carbon ion radiation with doses, the expression of p53 upregulated with doses exposed to X-ray or carbon ion. The cell number in G2/M of H1299 and apoptosis were increasing at all time points with doses in 12C6+ ion irradiation group. The results suggested that the effects of carbon ions or X rays ir-radiation on lung carcinoma cells were different, 12C6+ ion irradiation could have more effect on upregulating the ex-pression of p53 than X-ray, and the upregulated expression of p53 might produce the cellular cycle G2/M arrested, apoptosis increasing; and p53 gene might affect the lung cancer cells radiosensitivity.     

The selection and characterization of the mutants in bioflocculant bacteria C8 induced by 3 MeV helium ion irradiation

A 3 MeV He²⁺ beam was used to irradiate C8 (a flocculant-producing bacteria) with a fluence ranging from 10¹¹ to 10¹³ ions/cm². The effects on the survival ratio, TTC-dehydrogenase activity, flocculating activity and RAPD analysis are reported. The survival ratio curve caused by irradiation is proved to be “saddle-shaped”. Eleven mutants were obtained, all of which had a significant change in dehydrogenase activity and most showed a positive change in flocculating activity. RAPD measurements were used to analyse the DNA of mutants with a flocculating activity over 80%, which indicated that all their DNA had been changed by irradiation.     

螺旋藻-黄秋葵饲料添加剂对南美白对虾生长发育的影响

向南美白对虾的基础饵料中添加螺旋藻-黄秋葵精粉,研究其对南美白对虾的促生长效能。结果表明:4%的添加量对提高南美白对虾生长性能的效果最佳,此时成、幼虾体增重率分别为32.19%和103.73%,相比对照组提高了22.72%和46.76%,螺旋藻-黄秋葵复合饲料添加剂更有利于提高幼虾的生长性能。此外,螺旋藻-黄秋葵精粉对南美白对虾个体成活率也有不同程度的提高。     

供水管道爆漏事故影响因素实例分析

以S市供水管网2000~2005年6年的管道维修记录为基础,运用统计分析方法深入研究对管网爆、漏事故产生长、短期作用的两类影响因素。采用生存分析法比较不同管材、管径管道的生存率大小。计算气候因素与事故率的相关性,得出月均温度和年降水量与事故率的Pearson相关系数,并用幂函数曲线拟合月均温度与月事故率的关系。     

4名^60Co源辐照事故中受照者的剂量估算

对一起＾６０Ｃｏ源辐照事故中受到过量照射的人员，通过现场调查和模拟试验，确定了照射的几何条件和受照时间，估算了４名受照者的造血干细胞活存计权等效剂量。最后将物理方法与生物学方法估算的剂量数据作了比较。     

An investigation of factors that influence the duration of IT outsourcing relationships

Past studies in the IT outsourcing area have examined the management of IT outsourcing relationships from a variety of perspectives. The present paper extends this line of research. In this study, we take a multi-theoretic perspective to explore factors that determine the duration of continuing IT outsourcing relationships between vendor and client firms. Five ex-ante and two ex-post factors that may influence relationship duration were examined in this study. Data for this study were collected using a nationwide survey. To investigate the dynamics of continuing outsourcing relationships through repetitive contracts, we performed survival analysis using an accelerated failure-time (AFT) model. Four factors are found to have a significant relationship with relationship duration as hypothesized. However, three factors, of which two are ex-post factors, are found to not have a significant impact on outsourcing relationship duration. Implications and contributions of the study are discussed.     

陆基巡航导弹发射设备生存能力分析

针对现代战争条件下,巡航导弹发射设备可能遭到敌方攻击的课题,提出了陆基巡航导弹发射设备生存能力的问题;引入了生存概率以估算陆基巡航导弹发射设备生存能力,并分析了提高生存能力的措施;介绍了采用机动快速的发射方式及涉及的关键技术;总结了发射车辆伪装隐蔽的常用措施;阐述了采用防护加固提高生存能力的办法.为提高陆基巡航导弹发射设备生存能力,采用机动快速、伪装隐蔽和防护加固的措施,对提高巡航导弹武器系统作战效能具有重要意义.