揭开利爪之谜--破解七十年前的一个科学悬案

一种罕见的古怪动物,一桩搁置七十年悬案。它们会是夜空的精灵,还是天生的杀手？年轻的动物专家深入古老洞穴,搜寻黑暗中隐藏的真相。     

A Generic Model to Solve Tactical Planning Problems in Flexible Manufacturing Systems

This paper is an attempt to develop a generic modeling framework that addresses tactical planning problems of flexible manufacturing systems in a coherent manner. We propose a generic 0-1 mixed integer programming formulation, that integrates batching, loading, and routing problems with their critical aspects related to a system's performance. For this purpose, a thorough analysis is made to determine and relate system components, their attributes, and alternatives together with performance measures specific to tactical planning. This provided the justification to support our argument about generality of the model. A linear programming formulation is provided to approximate the mixed integer formulation proposed so as to overcome the problem's combinatorial complexity. The potential capability of the linear approximation proposed also is demonstrated via a small set of test problems.     

体细胞克隆发展现状、出现问题及解决方法

目前体细胞克隆技术在畜牧业的许多领域都有着广泛的应用,但体细胞克隆效率低下却严重影响了该技术在畜牧业的发展.几乎所有的克隆动物都有胎盘肥大和表观遗传异常现象,这也是制约克隆效率的重要原因.综述了体细胞克隆的发展现状,阐述了体细胞克隆的胎盘肥大和重编程异常现象.并探讨了利用四倍体补偿法改善克隆胎盘肥大和通过对表观遗传基因的调控提高克隆效率的新方法.     

“Can breast feeding help you in later life? Evidence from German military heights in the early 20th century”

Considerable literature exists on the benefits of breast feeding on the health and survival of infants and young children, but there is less on the effects on later life outcomes. One such measure of health and well-being that has received attention in the historical literature is terminal adult stature. Information on height is rather widely available; however, it is much more difficult to obtain data on breast feeding. One country that does have such information is Imperial Germany (1871-1919). A number of physicians and local health officials collected information on the incidence and duration of breast feeding early in the 20th century, particularly because of concern about the unusually high infant mortality rates in parts of Germany. Hallie Kintner has surveyed the published results of these studies. The information on the prevalence of breast feeding for the period 1903/10 has been inputed into a database of demographic and economic variables for the counties (Regierungsbezirke) of Germany (1850-1939). There are also published data on heights of military recruits from the Imperial German military forces in 1906. These can be linked to areas in the database and related to breast feeding practices and infant mortality both contemporaneously and approximately 20 years previous to 1906. Results indicate a significant effect of infant feeding practices on later life outcomes operating through infant health conditions, proxied by the infant mortality rate.     

四川毛茛属五新种和一新变种,其中一新种代表一新组

该文描述了自四川西部发现的毛茛科毛茛属五新种.其中:三新种,即石棉毛茛(Ranunculus shimianensis)、细叉叶毛茛(R.tenuifurcatus)和细裂叶毛茛(R.perdissectus)隶属于美丽毛茛组(Sect.Auricomus);第四新种,即泸定毛茛(R.ludingensis)隶属于毛茛...     

Assessing Diabetes Self-Management with the Diabetes Self-Management Questionnaire (DSMQ) Can Help Analyse Behavioural Problems Related to Reduced Glycaemic Control

Aim

To appraise the Diabetes Self-Management Questionnaire (DSMQ)’s measurement of diabetes self-management as a statistical predictor of glycaemic control relative to the widely used SDSCA.

Methods

248 patients with type 1 diabetes and 182 patients with type 2 diabetes were cross-sectionally assessed using the two self-report measures of diabetes self-management DSMQ and SDSCA; the scales were used as competing predictors of HbA_1c. We developed a structural equation model of self-management as measured by the DSMQ and analysed the amount of variation explained in HbA_1c; an analogue model was developed for the SDSCA.

Results

The structural equation models of self-management and glycaemic control showed very good fit to the data. The DSMQ’s measurement of self-management showed associations with HbA_1c of –0.53 for type 1 and –0.46 for type 2 diabetes (both P < 0.001), explaining 21% and 28% of variation in glycaemic control, respectively. The SDSCA’s measurement showed associations with HbA_1c of –0.14 (P = 0.030) for type 1 and –0.31 (P = 0.003) for type 2 diabetes, explaining 2% and 10% of glycaemic variation. Predictive power for glycaemic control was significantly higher for the DSMQ (P < 0.001).

Conclusions

This study supports the DSMQ as the preferred tool when analysing self-reported behavioural problems related to reduced glycaemic control. The scale may be useful for clinical assessments of patients with suboptimal diabetes outcomes or research on factors affecting associations between self-management behaviours and glycaemic control.     

Low Physical Activity and High Screen Time Can Increase the Risks of Mental Health Problems and Poor Sleep Quality among Chinese College Students

Objective

To test the independent and interactive associations of physical activity (PA) and screen time (ST) with self-reported mental health and sleep quality among Chinese college students.

Method

Data were collected in October, 2013. The gender, age, residential background, body mass index (BMI), perceived family economy and perceived study burden were obtained from a total of 4747 college students (41.6% males and 58.4% females). The outcomes were self-reported PA status, ST, anxiety, depression, psychopathological symptoms and sleep quality. Analyses were conducted with logistic regression models.

Results

Overall, 16.3%, 15.9% and 17.3% of the students had psychological problems, such as anxiety, depression and psychopathological symptoms, respectively. The prevalence of poor sleep quality was 9.8%. High ST was significantly positively associated with anxiety (OR=1.38, 95%CI: 1.15-1.65), depression (OR=1.76, 95%CI: 1.47-2.09), psychopathological symptoms (OR=1.69, 95%CI: 1.43-2.01) and poor sleep quality (OR=1.32, 95%CI: 1.06-1.65). High PA was insignificantly negatively associated with anxiety, depression, psychopathological symptoms and poor sleep. Low PA and high ST were independently and interactively associated with increased risks of mental health problems and poor sleep quality (p<0.05 for all).

Conclusion

Interventions are needed to reduce ST and increase PA in the lifestyles of young people. Future research should develop and measure the impacts of interventions and their potential consequences on sleep, health, and well being.