我国畜牧业的现状、问题及对策

文章揭示了我国畜牧业发展现状和存在的环境污染与生态破坏、分散养殖与动物疫病防治的矛盾、投入品使用不规范、资源短缺等问题及其产生的原因,在此基础上提出了发展生态畜牧业的6大对策措施和政策建议。     

Effect of Pediatric Influenza on Caregivers’ Burden—A Literature Review

Influenza, or the flu, is a common and potentially serious infection that disproportionally affects children with more than 20,000 yearly hospitalizations in children under the age of 5. A literature review of the caregiver burden associated with pediatric influenza was conducted. Two main types of burdens were identified: economic and noneconomic. Flu treatment costs $3,990 for pediatric inpatients services and $730 for emergency department (ED) pediatric patients. Caregivers may also face out-of-pocket costs ($178 for inpatients, $125 for ED patients, and $52 for outpatients) or those not covered by health insurance. Caregivers can also face indirect costs while caring for their children with the flu. Indirect costs were common, and 75% of pediatric caregivers reported these costs when caring for a sick child. Missed work is the most common indirect cost and is estimated as high as 73 work hours ($1,456) missed while caring for a sick child. Other costs associated with pediatric influenza included noneconomic burden: sudden changes in daily life, loss of leisure time, social disruption, and psychological impact or stress. Noneconomic burdens were also found to be significant and lowered the quality of life of caregivers even after the child’s illness. Socioeconomic status is an important predictor of influenza rates. Residents in high-poverty areas are three times more likely to have hospitalizations due to pediatric influenza than those in low-poverty areas. From the literature it is evident that pediatric influenza has demonstrated a considerable impact on caregivers’ lives both financially and in other aspects.     

大城市郊区化的“飞地模式”：基于武汉—利川季节性人口流动现象的分析

大城武汉与小城利川之间大规模、季节性人口规律性流动的现象表明,受较高土地价格、承接低端产业转移、管理水平相对较低等因素的影响,中国的城市外围往往被规划为城市的预留发展区域,没有成为城市中产阶层郊区化、逆城市化的首选区域。而远离城市、环境宜居的偏远小城却成为了城市中产阶层追求更加从容舒适的生活空间与生活方式的实质性“郊区”,从而形成了具有中国特色郊区化的“飞地模式”。郊区化的“飞地模式”实践是市民能动地追寻他们理想中的“郊区”所作的变通,是被抑制的郊区化需求的变相满足。在中国城市化进程放缓、经济发展转入中速发展的背景下,充分尊重并多元化满足城市中产阶层的郊区化需求,将郊区化、逆城市化战略提上议事日程,是中国未来经济社会发展的重要方向。     

Early Sales of Seasonal Products with Weather‐Conditional Rebates

Some retailers of seasonal products adopt weather‐conditional rebate programs to induce early sales and increase profits. In such promotions, customers who buy the product in an advance preselling period are offered rebates if a pre‐specified weather condition is realized during the later normal selling season. We investigate the potential benefits of these programs for retailers. We show that the weather‐conditional rebate program can increase sales by price discriminating among a customer's post‐purchase states. Taking advantage of the early sales, it can also reduce the inventory holding cost and ordering cost, and hence can increase the retailer's expected profits. In addition, we numerically investigate the sensitivity of the rebate program's effectiveness to the model parameters and illustrate its advantages over an advance‐discount policy.     

Dose-response assessment for influenza A virus based on data sets of infection with its live attenuated reassortants

Reported data sets on infection of volunteers challenged with wild-type influenza A virus at graded doses are few. Alternatively, we aimed at developing a dose-response assessment for this virus based on the data sets for its live attenuated reassortants. Eleven data sets for live attenuated reassortants that were fit to beta-Poisson and exponential dose-response models. Dose-response relationships for those reassortants were characterized by pooling analysis of the data sets with respect to virus subtype (H1N1 or H3N2), attenuation method (cold-adapted or avian-human gene reassortment), and human age (adults or children). Furthermore, by comparing the above data sets to a limited number of reported data sets for wild-type virus, we quantified the degree of attenuation of wild-type virus with gene reassortment and estimated its infectivity. As a result, dose-response relationships of all reassortants were best described by a beta-Poisson model. Virus subtype and human age were significant factors determining the dose-response relationship, whereas attenuation method affected only the relationship of H1N1 virus infection to adults. The data sets for H3N2 wild-type virus could be pooled with those for its reassortants on the assumption that the gene reassortment attenuates wild-type virus by at least 63 times and most likely 1,070 times. Considering this most likely degree of attenuation, 10% infectious dose of H3N2 wild-type virus for adults was estimated at 18 TCID50 (95% CI = 8.8-35 TCID50). The infectivity of wild-type H1N1 virus remains unknown as the data set pooling was unsuccessful.     

我国工业增加值季节波动非线性研究——基于SEATV-STAR模型

多数宏观经济变量时间序列有季节波动,如果季节波动是非线性的,采用经季节调整过的数据或传统季节模型等线性处理季节波动的方法可能就不再适用。本文基于季节时变平滑转换自回归(SEATV-STAR)模型,运用"特殊到一般"的非线性检验策略对我国工业增加值季度增长率季节波动进行研究。结果表明:(1)工业增加值的季节波动兼有结构时变和非线性改变,工业增加值的周期波动是线性的。(2)技术进步、体制变迁等因素使得工业增加值季节波动发生连续的结构时变,它们是季节波动变化的主要影响因素。(3)工业增加值周期波动对其季节波动有非对称影响;在工业增加值的波峰阶段,其季节波幅会减小,且1、2季度工业增长率有明显提高。     

New Health Risks and Sociocultural Contexts: Bird Flu Impacts on Consumers and Poultry Businesses in Lao PDR

Avian flu has been identified as one of the most challenging new risks, global in impact due to the "highly interconnected and integrated world economy along with other unpredictable events such as the Asian financial crisis and global terrorism." We have chosen the case of Lao PDR to shed light on an area in which local people consume chicken as one of their staple foods. Our research analyzes consumer behavior, poultry business modification patterns in a high-risk country, and government reaction for business resilience. The geographic choice is motivated by the 2006 EIU report on Catastrophe Risk Management that indicated that Asian-Pacific companies are better prepared for such risks as bird flu than European business is, despite the many cases found in both regions.     

Trends cycles and seasons: Econometric methods of signal extraction

Alternative methods of trend extraction and of seasonal adjustment are described that operate in the time domain and in the frequency domain.

The time-domain methods that are implemented in the TRAMO–SEATS and the STAMP programs are compared. An abbreviated time-domain method of seasonal adjustment that is implemented in the IDEOLOG program is also presented. Finite-sample versions of the Wiener–Kolmogorov filter are described that can be used to implement the methods in a common way.

The frequency-domain method, which is also implemented in the IDEOLOG program, employs an ideal frequency selective filter that depends on identifying the ordinates of the Fourier transform of a detrended data sequence that should lie in the pass band of the filter and those that should lie in its stop band. Filters of this nature can be used both for extracting a low-frequency cyclical component of the data and for extracting the seasonal component.     

从"猪流感"到"甲型H1N1流感"——谈汉语引进术语的科学性和民族性

目前世界上正在流行的流感,最初被称为“猪流感”,又有多种命名,后来被称为“A（H1N1）”,汉语用“甲型H1N1”去指称。汉语对这一学科术语的引入具有科学性,又具有民族性,具有中文、英文合璧的意味。     

MODELLING EPIDEMIC DISEASES

This paper traces the development of mathematical models for epidemics from the 18th century to the present day. The models are shown to be of use in predicting and controlling the spread of infection.