Inventory control in hospital blood banks

The delicate relationship between donors and the Transfusion Service in the U.K. implies a clear duty to make the best possible use of the limited blood supplies, and this turns attention upon the stocking policies adopted by Hospital Blood Banks. Whereas Blood Bank staff can obtain an intuitive grasp of the effects of various stock levels for the common bloods, this is not usually the case for the rare bloods which are more difficult to control. A policy decision has to be made which balances the conflicting stock requirements of maintaining a high availability and also low out-dating rates. A Markovian structure is exploited in this paper for this purpose and the effects of the key variables are shown to be interrelated. In any particular instance the form of the probability distribution of demand between replenishments, the scale of the throughput, the blood life in relation to the ordering interval, the fraction of blood transfused and the fraction of the replenishment order which is supplied to the Bank will together determine the form of the operating characteristics.     

Hearth and Home: The Living Arrangements of Mexican Immigrants and U.S.-Born Mexican Americans

Utilizing data from the nationally representative, 1990 Panel Study of Income Dynamics—Latino Sample, this paper examines the living arrangements of Mexican heritage persons in the U.S., comparing immigrants to U.S. natives. Mexican immigrants are most likely to live with extended kin and unrelated persons upon recent arrival to the U.S. As time in the U.S. increases, such arrangements become less common. Three competing explanations for this pattern are addressed. While economic resources and life course stages are clearly linked to household formation for immigrants and U.S. natives, the findings indicate limited support for an acculturation hypothesis.     

Dimensions of Internet use: amount,variety, and types

We examine the dimensions of Internet use based on a representative sample of the population of the UK, making three important contributions. First, we clarify theoretical dimensions of Internet use that have been conflated in prior work. We argue that the property space of Internet use has three main dimensions: amount of use, variety of different uses, and types of use. Second, the Oxford Internet Survey 2011 data set contains a comprehensive set of 48 activities ranging from email to online banking to gambling. Using the principal components analysis, we identify 10 distinctive types of Internet activities. This is the first typology of Internet uses to be based on such a comprehensive set of activities. We use regression analyses to validate the three dimensions and to identify the characteristics of the users of each type. Each type has a distinctive and different kind of user. The Internet is an extremely diverse medium. We cannot discuss ‘Internet use’ as a general phenomenon; instead, researchers must specify what kind of use they examine.     

When 'Choice' and 'Choice' Are not the Same: Institutional Frameworks of Choice in the German Welfare System

The creation and strengthening of welfare markets in Germany means that citizens can increasingly choose among competing providers of welfare goods and services. However, the conditions under which citizens may exercise choice in various fields of social policy are quite different. A major reason for these differences can be found in the public institutions that frame citizens' choice in welfare markets. This article analyses welfare markets in German health care, long-term care, pensions and employment policies, paying special attention to the respective public institutional frameworks. It will be argued that differences between frameworks of choice can be categorized by means of four parameters representing different aspects of public involvement in welfare markets. Depending on the kind and the degree of public involvement, welfare markets may be compatible with 'traditional' notions of public responsibility for citizens' social security.     

Introduction to the special issue

No sociologist … should think himself too good … to make tens of thousands of quite trivial computations in his head and perhaps for months at a time (Weber 1946, p. 135). who has special interests in social change, political sociology, computers, methodology, and statistics. For the past decade he has been an independent consultant specializing in statistical data analysis and data base management for both mainframe and microcomputers.     

Expanding the learning day: an essential component of the community schools strategy

Community schools expand learning time and opportunities as one important dimension of a comprehensive strategy to ensure that students are ready for college, career, and citizenship.