Prospects for food security in the 21st Century: with special emphasis on Africa

Food security for the world in 2025 is possible and probable if the right set of things are done, starting now. But the task will not be easy. It is both a technology and a political/economic challenge. The challenge for sub-Saharan Africa is even greater. While other regions improved per capita food availability over the last 30 years, Africa's availability declined. But food security is about more than supply. It is also about access which means income generating employment is critical. Meeting future requirements in Africa and the world will require sustainable intensification of complex production systems, appropriate national and international policies and continued investments in agricultural research. Without these conditions and increased employment intensive growth, prospects for the future are less bright.     

加强高校学生的素质教育,教师是关键

教师在素质教育中起关键性作用。在实施素质教育的过程中 ,教师应从以下方面努力 :1、提高自身的综合素质 ;2、改革课堂教学 ,让课堂真正属于学生 ;3、改革教学内容 ,创新教学方法 ;4、革新观念 ,承认素质教育的差异性。     

保密通信中的分形调制技术

分形调制在保密通信中具有广阔的应用前景。介绍了分形调制的原理,讨论了其在多速率分集、抗1/f噪声、抗频率选择性衰落、适用于信道条件复杂的MIMO通信系统等方面的特点。由于作为密钥的小波基任意多,且可根据信道情况在不同的小波基之间跳变,故分形调制具有极强的保密性和抗破译能力。     

几种发射分集OFDM系统信道估计方法性能评估

给出了3种基于发射分集的OFDM系统信道估计方法,分别从训练序列对算法的影响、估计准确度、算法复杂度和算法适用性等方面对各自性能作了分析比较,并进行了仿真.分析比较和仿真结果表明,训练序列对3种算法的影响很大,通过训练序列的正交化设计,LS和EM算法可以得到很大程度的简化;EM算法与LS算法估计精度相当,信噪比较大时,多项式模型算法估计精度要远远高于LS和EM算法;总体上来说,多项式模型算法复杂度最高,EM算法复杂度最低.     

The social value of income information in a model with market power and endogenous variety

The present paper analyzes the value of public information in a general equilibrium economy with imperfect competition. The welfare effects of an improved information system for perfectly competitive economies have been extensively investigated in the published literature. Schlee (2001) shows that the value of information is always negative in exchange economies if an efficient risk sharing mechanism exists. In contrast, in economies with production, better information reduces welfare provided consumers are sufficiently risk-averse ( Eckwert and Zilcha 2000, 2003 ). In the present paper it will be shown that this result is robust if the production sector exhibits monopolistic competition in the Chamberlinian sense. Even so, the inefficiency of equilibria adds further potential for positive welfare effects of improved information. A model is presented where the degree of market imperfection is positively linked to the value of information. If the markup on competitive prices is sufficiently high, the value of information is positive; that is, better information increases economic welfare.     

Advertising,concentration and profitability in Greek food manufacturing industries

The conventional framework for cross-sectional studies of industrial organisation focuses on the hypothesised relations among structure, conduct and performance (SCP). This paper investigates these relationships for the food and beverage manufacturing industries in a European country, i.e., Greece. 3SLS method is used to estimate the parameters of the profitability, concentration and advertising model for a sample of 38 four-digit industries in 1994. The main results, which are in line with the relevant empirical work, show that profitability is determined by advertising, which, in turn, is affected by both profitability and concentration, while the latter is determined by economies of scale.     

Food choice models and their relation with food preferences and eating frequency in the Polish population: POFPRES study

A sample of 9339 subjects aged 13–75, living in the six macro-regions of Poland rated the preferences of 140 various food products, eating frequency and factors influencing food choice. Four groups of consumers were found: “consumers susceptible to advertising and seeking novel healthy products” (33.2% of the sample), “consumers not taking care of their health” (25.4%), “consumers not susceptible to advertising and taking care of their health” (32.5%), and “consumers insensitive to sensory attributes of fruit and vegetables” (9.0%). Among factors influencing the food choice, sensory and functional factors were significant, and health and price – moderate. Advertising was generally denied as an important factor in food choice. The food choice motives were highly dependent on age and gender, and to a lower extent – on region of residence, size of place of residence, economic condition and education level. Women/girls more often showed pro-health behaviours in food choice, choice motives, preferences and food intake.     

Metamorphosis in hospitality: A tradition of sexual harassment

This study measures the incidence and tolerance of sexual harassment in hospitality in an effort to understand its causes. It examines the tradition of sexual behaviour in hospitality, exacerbated by hierarchical structures, the nature of hospitality work, the characteristics of typical front line workers, customers’ reduced sense of responsibility, and an emphasis on meeting customers’ needs. Customer contact is shown to be a key predictor of harassment, especially for young European women. The typical profiles of hospitality staff and the nature and traditions of the industry are considered important causes of harassment in hospitality.     

TD-SCDMA系统中一种软件集成智能天线算法

给出了一种采用信干噪比准则的、集成了预多波束天线与LMS自适应天线的软件天线方案,该方案采用开关合并方法,把软件天线输出接到最大输出信噪比的算法输出,实现算法分集.在TD-SCDMA动态模型上对提出的方法进行了仿真,结果表明,采用集成软件天线方案的误码率性能要优于单纯的预多波束天线或LMS自适应智能天线.仿真过程考虑了用户来波方向和用户到基站距离的动态变化,以及功率控制算法和系统同步过程的影响.     

消费者对生态标识食品的多层面认知行为:基于MVP模型的实证分析

笔者基于山东省693个样本数据,以绿色食品为例,将消费者认知行为划分为知晓、识别与使用三个层面,构建多变量Probit模型,分析在消费者认知程度提高过程中起主要作用的因素。研究发现,男性或年轻受访者在知晓层面的认知率较高,而女性、年长受访者在识别和使用层面的认知率相对较高;收入和卷入程度的影响在知晓层面不显著,而在识别和使用层面显著;学历、子女状况与环境保护意识的影响在各层面皆显著;食品安全意识与信息渠道的影响在较低层面显著,而在较高层面不显著。消费者认知行为的异质性为市场细分与开发提供了空间。厂商应针对不同群体采取差异化营销战略,引导消费者认知行为,促进潜在需求向现实需求转化。