中国人口增长预测

利用《中国人口统计年鉴》中的部分数据,结合中国人口增长特点,建立了以女性为主的数学模型.利用该模型对我国总人口、人口老龄化、未来育龄妇女人数等作了预测.

Effect of Some Bioproducts on Winter Mortality of Grafted Buds and the Number of Maiden Fruit Trees Produced in an Organic Nursery

In an organic nursery, various bioproducts were used to stimulate plant growth： Fertigo （granulated bovine manure）, Micosat, Humus UP （humic acids microbiologically enriched）, Humus Active ＋ Aktywit PM （beneficial microorganisms）, BioFeed Amin, BioFeed Quality, Tytanit, and Vinassa. One of the aims of the study was to determine the effect of these products on the ability of grafted buds of apple and sour cherry cultivars to survive the winter. Losses resulting from the freezing of buds during winter dormancy were calculated as the difference between the number of buds deemed to have taken in autumn and the number of live buds that began to develop properly in the spring of the following year. In autumn, the number of maiden trees obtained in each fertilization combination was also determined in the same nursery. The greatest tendency to die in winter was shown by apple and sour cherry buds in those combinations in which the rootstocks were supplied with a mineral fertilizer with NPK components, and the smallest where humic preparations （so-called vermiculites） were used. The type of fertilizer had an indirect influence not only on the number of grafted buds that died in winter as a result of freezing, but also on the final number of maiden trees obtained from a given area of the nursery.

The Influence of PAC on Female Reproductive Health

[Purpose]To discuss the influence of PAC on female reproductive health after abortion. [Method] It selects 3020 patients of voluntarily making abortion operation in our hospital from 2011.3-2013.03, where the PAC patients are 1860 cases in the system, and the non- PAC patients are 1160 cases, conducting analysis of its clinical materials. [Result]The selection rate of reliable contraception measures in PAC group is obviously higher than non-PAC group, and the difference is of statistics significance（P〈0.05）. The repeated abortion rate in PAC group is obviously lower than the control group, and the difference is of statistics significance（P〈0.05）. [Conclusion] PAC service has a positive influence on the female reproductive health, which can improve the selection rate of patients for reliable contraception measures, reducing the repeated abortion rate, which plays a positive role in protecting the patients＇ reproductive health aspect.

Evaluation of Fertility Levels and Adjustment of Fertility Policy: Based on the Current Situation of the Chinese Mainland's Provincial Fertility Levels

During the 11th Five-year Plan （2006-2010）, the total fertility rate of the mainland of China was 1.481 and was stable with a slight decline, exhibiting a spatial pattern of moderately low fertility in the central and western regions, very low fertility in the east and extremely low fertility in the northeast. Except for a rebound in a few provinces and regions with extremely low fertility rates, the ratio of actual fertility rates to policy fertility rates is still falling. The reduced fertility rate is mainly driven by development, notably the proportion of the total population represented by the exuberantly fertile women of child-bearing age and their greater urbanization, growing level of non-agricultural employment and outflow from rural areas, as well as the assimilative effect of urban production, lifestyles and culturalconcepts upon the agricultural population. Development has catalyzed an irreversible trend of declining fertility; existing fertility policy has proven insufficient to keep fertility rates stable at reasonably low levels. Policy-based rebounds may emerge in urban areas and the east and northeast, where family planning policy has been better implemented; on the other hand, a non-policy-based rebound may have been released. In the central and western rural areas, multiple births occur on average among only 4.12 percent of the younger generation of women. As fertility policy is adjusted and improved, fertility rebounds in transitional fertility policy adjustment can be effectively regulated through a gradual strategy which will not provoke a sharp rebound. The time is ripe for China to conduct a nationally unified adjustment of the existing fertility policy.

Ruin probabilities with insurance and financial risks having an FGM dependence structure

We consider a discrete-time risk model,in which insurance risks and financial risks jointly follow a multivariate Farlie-Gumbel-Morgenstern distribution,and the insurance risks are regularly varying tailed.Explicit asymptotic formulae are obtained for finite-time and infinite-time ruin probabilities.Some numerical results are also presented to illustrate the accuracy of our asymptotic formulae.

Prevalence of seat belt and mobile phone use and road accident injuries amongst college students in Kerman, Iran

Objective： To investigate the prevalence of mobile phone and seat belt use in driving in college students aged 18-24 years. Methods： The study consisted of two phases. In the first phase, a questionnaire was given to 265 college students. The sample contained 188 males and 77 females. In the second phase, the data pertaining to road accident injuries from March 20, 2007 to March 20, 2008 were collected from Bahonar Central Hospital in Kerman, Iran, and analyzed. Results： There were 14.0% of male and 19.0% of female participants traveled belted while driving on urban roads. It indicated that the participants unbelted or using mobile phone were more involved in accidents in last threeyears. This study also revealed that 19.0% of male and 4.2% of female drivers considered using mobile phone in driving not hazardous. The highest injury and property damage crash rates were 87 and 137 per 100 000 inhabitants, which occured in male group aged 18-24 years. And 30% of all fatalities were 19-24 years old. Conclusions： More than 50% ofcoUege students traveled unbelted. The females were less involved in road accident injuries. The college students aged 18-24 years had the highest percentages of trauma and head injury.