Drivers and Outcomes of Long‐term Orientation in Cooperative Relationships

We argue in this paper that a buyer may deliberately develop long‐term orientation as a governance mechanism to deal with risks arising from exchange hazards, and to reduce the opportunistic behaviour of a supplier. While the exchange hazards of asset specificity pose a safeguarding problem, those of market uncertainty pose an adaptation problem. We test our model on a sample of 221 procurement partnerships. Our results show that satisfactory prior history of a supplier, asset specificity of the buyer and market uncertainty are all positively related to a buyer's long‐term orientation towards a supplier. Consistent with the idea that asset specificity and market uncertainty pose different governance problems, we find that satisfactory prior history reduces the positive relationship between asset specificity and a buyer's long‐term orientation, but enhances the positive relationship between market uncertainty and a buyer's long‐term orientation. We also find that a buyer's long‐term orientation fully mediates the relationship between satisfactory prior history and a supplier's opportunistic behaviour. Finally, implications on the theory and the practices of relationship governance are discussed.     

Sample size calculation for testing non-inferiority and equivalence under Poisson distribution

When counting the number of chemical parts in air pollution studies or when comparing the occurrence of congenital malformations between a uranium mining town and a control population, we often assume Poisson distribution for the number of these rare events. Some discussions on sample size calculation under Poisson model appear elsewhere, but all these focus on the case of testing equality rather than testing equivalence. We discuss sample size and power calculation on the basis of exact distribution under Poisson models for testing non-inferiority and equivalence with respect to the mean incidence rate ratio. On the basis of large sample theory, we further develop an approximate sample size calculation formula using the normal approximation of a proposed test statistic for testing non-inferiority and an approximate power calculation formula for testing equivalence. We find that using these approximation formulae tends to produce an underestimate of the minimum required sample size calculated from using the exact test procedure. On the other hand, we find that the power corresponding to the approximate sample sizes can be actually accurate (with respect to Type I error and power) when we apply the asymptotic test procedure based on the normal distribution. We tabulate in a variety of situations the minimum mean incidence needed in the standard (or the control) population, that can easily be employed to calculate the minimum required sample size from each comparison group for testing non-inferiority and equivalence between two Poisson populations.     

Exact sample-size determination in testing non-inferiority under a simple crossover trial

For testing the non-inferiority (or equivalence) of an experimental treatment to a standard treatment, the odds ratio (OR) of patient response rates has been recommended to measure the relative treatment efficacy. On the basis of an exact test procedure proposed elsewhere for a simple crossover design, we develop an exact sample-size calculation procedure with respect to the OR of patient response rates for a desired power of detecting non-inferiority at a given nominal type I error. We note that the sample size calculated for a desired power based on an asymptotic test procedure can be much smaller than that based on the exact test procedure under a given situation. We further discuss the advantage and disadvantage of sample-size calculation using the exact test and the asymptotic test procedures. We employ an example by studying two inhalation devices for asthmatics to illustrate the use of sample-size calculation procedure developed here.     

Population programme of China]

Results of population programs started in China during the last decade have attracted worldwide attention. The Chinese population issues are important due to the following characteristics: 1) China is the most populated country in the world, with over 1 billion people (22% of world population), by the end of 1980; 2) its population is 80% rural; 3) despite improved living conditions that have helped lower the mortality rate from over 20/1000 before Liberation to 10/1000 in the 1960s and finally 6-8/1000 during the last decade, the Chinese population has increased from 540 million soon after Liberation to the current 1 billion, with an average yearly growth rate of 2%; 4) China has a young population, with 36.8% under 14 years old and less than 5% over 65, hence education and employment are big issues; and 5) due to longterm backward economy resulting from feudal and colonial influence before Liberation, efforts in developing a strong Chinese economy have met with many obstacles. The above 5 features of the Chinese population have important bearing on solving China's population problems and in building its economy, developing its society, and realizing its 4 modernizations. Although China is self-sufficient despite its large population, it faces many problems and challenges especially in the areas of educating its young population and subsequent employment. To achieve a strong economy and to improve the welfare of its people, China has put efforts into controlling the size and improving the quality of its population during the past decade. Programs in population control will continue to take priority in China.     

The moderating effect of alcohol use on protective and risky sex behaviors among college students in the Southeast United States

ABSTRACT

Objective: College students are a high-risk population for new human immunodeficiency viruses (HIV) diagnoses. Although condom use self-efficacy and HIV knowledge can protect against risky sexual behavior (RSB), these same protective factors have been shown to exacerbate RSB. The influence of alcohol use can further complicate these protective factors to influence RSB. Participants: 689 African American/Black and non-Hispanic White college students attending a public university in the Southeast United States. Method: This study sought to examine the relations between condom use self-efficacy and HIV knowledge with RSB and the moderating effect of alcohol use. Results: Findings showed positive associations between RSB and HIV knowledge and alcohol use. Unexpectedly, low frequency drinkers with high condom use self-efficacy were at increased risk for RSB compared to high frequency drinking counterparts. Conclusions: Findings point to the need to target prevention services for low-risk drinkers in college settings.     

Population and employment in China]

The unequal distribution of farmlands in rural areas and the extremely low productivity in the cities were the fundamental causes of unemployment and population problems in old China. Tremendous progress was made after 1949. The serious economic disturbances caused by Lin-piao and the "Gang of Four" caused great unemployment again. The slow development of China's productivity, poor business management, the involvement of women in social activities, the morality rate decrease, and the population growth rate increase are the main reasons for China's unemployment problem. The fundamental solution is to respect the objective laws of nature and economics and to develop social productivity. In the country we should implement the total development of agricultue, forestry, animal husbandry, and fishery. In towns and cities service occupations and handicraft industries should be developed, education and humanities need to be improved, and transportation, communications, and many other industries are still backward. There is high potential for development and vast opportunities for additional labor. We should constantly cultivate our high quality workforce to meet the demand of modernization. Population control is important because the higher the population growth rate the slower the accumulation of wealth. Instead of being a producer for the society the additional labor can be a burden. The vital factor in achieving the "Four Modernizations" is not the quantity of labor but the increase in productivity.     

Daily rhythm of salivary IL-1ß, cortisol and melatonin in day and night workers

Shiftwork-induced sleep deprivation and circadian disruption probably leads to an increase in the production of cytokines and dysregulation of innate immune system, respectively. This project aims evaluating changes in salivary IL-1 beta, cortisol, and melatonin in night workers. Method. Two day and three night healthy workers participated in this study. Sleep was evaluated by actimetry and activity protocols. Saliva was collected at waking and bedtime the last workday and the following two days-off and was analyzed by ELISA. Results. Neither sleep duration nor efficiency showed any association with salivary IL-1beta. IL-1beta levels were higher at waking than at bedtime during working days for all workers, but only one day and one night-worker maintained this pattern and hormone rhythms during days off. For this night worker, melatonin levels were shifted to daytime. A second one presented clear alterations in IL-1beta and hormone rhythms on days-off. Conclusions. Our preliminary results suggest that night work can disturb the variation pattern of salivary IL-1beta. No association of this variation with sleep was observed. It seems that disruption in hormone rhythms interfere with salivary IL-1beta production. IL- 1beta production pattern seems to be maintained when rhythms are present, in spite of a shift in melatonin secretion.     

Sample size determination for cluster randomization phase II trials of dichotomous data

One of the main goals for a phase II trial is to screen and select the best treatment to proceed onto further studies in a phase III trial. Under the flexible design proposed elsewhere, we discuss for cluster randomization trials sample size calculation with a given desired probability of correct selection to choose the best treatment when one treatment is better than all the others. We develop exact procedures for calculating the minimum required number of clusters with a given cluster size (or the minimum number of patients with a given number of repeated measurements) per treatment. An approximate sample size and the evaluation of its performance for two arms are also given. To help readers employ the results presented here, tables are provided to summarize the resulting minimum required sample sizes for cluster randomization trials with two arms and three arms in a variety of situations. Finally, to illustrate the sample size calculation procedures developed here, we use the data taken from a cluster randomization trial to study the association between the dietary sodium and the blood pressure.     

先进的管制方式需要相应的管制体制——自然垄断产业应用激励性管制的管制体制基础

激励性管制目前在发达国家的自然垄断产业得到了广泛应用,并取得了明显效果。发达国家在应用激励性管制方式时,同时进行了自然垄断产业的管制体制改革,通过管制权力运行机制和管制权力监督机制的建立和完善,构建了激励性管制应用的管制体制基础。我国在自然垄断产业引入激励性管制,存在着先进的管制方式与落后的管制体制之间的矛盾。因此,在引入激励性管制时,必须要进一步推进自然垄断产业管制体制的改革。     

Psychological Well-Being and Adolescents’ Internet Addiction: A School-Based Cross-Sectional Study in Hong Kong

This study examines the correlations of adolescents’ self-esteem, loneliness and depression with their internet use behaviors with a sample of 665 adolescents from seven secondary schools in Hong Kong. The results suggest that frequent online gaming is more strongly correlated to internet addiction and such correlation is higher than other predictors of internet addiction in online behaviors including social interactions or viewing of pornographic materials. Male adolescents tend to spend more time on online gaming than female counterparts. In terms of the effect of internet addiction on adolescents’ psychological well-being, self-esteem is negatively correlated with internet addiction, whereas depression and loneliness are positively correlated with internet addiction. Comparatively, depression had stronger correlation with internet addiction than loneliness or self-esteem. A standardized definition and assessment tool for identifying internet addiction appears to be an unmet need. Findings from this study provide insights for social workers and teachers on designing preventive programs for adolescents susceptible to internet addiction, as well as emotional disturbance arising from internet addiction.