A Numerical Solution to the Nonhomogeneous Two-Stage MVK Model of Cancer

In this article, we describe a straightforward method for solving the probability of at least one malignant cell by time t, and the associated hazard function, in the general (i.e., nonhomogeneous) two-stage Moolgavkar-Venzon-Knudson (MVK) model of cancer. The method consists of solving four coupled ordinary differential equations derived from the Kolmogorov backward equations for this process. The relationship of this method to previously proposed solutions is discussed.     

Sektion Jugendsoziologie Tätigkeitsbericht 2004

Ohne Zusammenfassung     

Interpersonal dependency of preferences

Standard decision theoretic models disregard the phenomenon of interpersonal dependency of preferences. In this paper it is argued that interpersonal dependency of preferences is a serious challenge for standard utility theory. First we sketch the more philosophical aspects of the problem and then, using a simple, formal model for the two-person case, we show that interpersonal dependency of preferences generally results in indeterminacy of preferences (resp. of subjective utility).     

The impact of social networks on the occupational status of migrants

This paper postulates that there is a continuous exchange of information and knowledge between those who share the common bond of having migrated to the US. The individual components of this information exchange constitute social networks. The 2 hypotheses tested are 1) immediate social networks and people known in the US facilitate the flow of information both to new migrants and between established migrants, thus promoting upward social mobility; and 2) access to broader network ties, organization membership, extra-ethnic friendships, and familiarity with established institutions smooths the transition process, resulting in increased social position. The data used comes from a study conducted in 1982-1983 in 4 Mexican sending communities (2 rural, 2 urban), for a total of 440 migrants. Results show that migrants in every socioeconomic bracket reported access to some or all social network characteristics. There was contact with either a family member or acquaintances from the migrants' town of origin. Over 50% of migrants reported knowing many fellow townspeople. Twice as many migrants belong to a sports club as to a social or religious organization. Very few rural migrants report knowing no townspeople, while 32% of urban migrants claim no knowledge of fellow migrants from their town of origin. Urban origin migrants report more contacts with those of other ethnicity than rural migrants. Those employed in agriculture are least acquainted with social information and contacts, while those in skilled and service sectors are well acquainted with them. The results of fact and analysis show that 1) access to personal US networks results in an average 4.4 point advantage in occupational prestige scores over no access, and 2) utilizing institutional US networks combined with any cumulative US experience gives a migrant a 5 point advantage over a fellow migrant with identical experience level but no institutional network contacts. This is also true for institutional Mexican networks. Thus success or failure in migrating is partly due to migrants' societal infrastructure and the fact that available information and social networks are accessed and utilized differently by different migrants.     

Assimilation process and group integration of migrant families

This empirical analysis gives 1st answers to the question of which effects some specific types of interaction structures within migrant families have on the assimilation process of family members and their personal integration. The analysis is based on a sample of 92 Turkish women and 123 Turkish men in the Bonn-Cologne area of West Germany. Questionnaires examine variables such as 1) urbanization of the context of origin, 2) household complexity, 3) availability of ethnic infrastructure, 4) residential proximity of Turkish friends and relatives; 5) school education of respondent and spouse; and 6) occupational prestige before migration. The study considers the following dimensions of social and cultural assimilation: 1) housing quality, 2) use of ethnic and general infrastructure, and 3) use of ethnic minority and mainstream cultural facilities. Results of empirical analyses on the housing conditions of migrants show that 1) motivational factors of the migrant family are unrelated to choice of a housing area, but are related to apartment quality; and 2) housing conditions differ markedly, depending on the type of combination of task-allocation and decision-making power in the family. Use of infrastructure 1) declines in Turkish families in which women's participation in family tasks is relatively high, 2) is determined most by the opportunity structure of the housing area and the interaction structure within the family; and 3) is a necessary step between the reorganization of the family's interaction structure and the participation in a broader spectrum of institutions of the receiving society. The family structure has no significant effect on participation in the minority culture. The extent of minority-culture rise has no direct relationship to the individual assimilation of family members. The empirical data support the basic theoretical assumption that the group integration of the migrant family has considerable effects on the assimilation process of its individual members. In conclusion, 1) opportunities for assimilation are increased by the combined resources of the migrants family household, and 2) continuing individual autonomy contributes severely to a reduced personal integration.     

Individual irrationality and social welfare

Individual preferences inconsistent with personal welfare caused neither by ignorance nor by a positive consideration for the welfare of others are defined as (welfare) irrational. Sources of irrationality (rigid adherence to moral principles, excessive fear of danger, excessive tempetation of pleasure, revenge, inertia, faulty telescopic faculty, the fallacy of diminishing marginal utility of utility, etc.) are discussed. An evolutionary explanation of irrationality is suggested and some implications for individual decision and social policy indicated.I am grateful to two anonymous referees for comments.     

Enrich marital inventory: a discriminant validity and cross-validation assessment

To assess the validity and clinical utility of the marital inventory ENRICH, a discriminant validity study was conducted using a national sample of 5039 married couples. The sample was randomly split in order to form a cross-validation group. ENRICH is a multidimensional scale and two types of analysis were conducted to assess the value of these various scales. Results from discriminant analysis indicated that using either the individual scores or couples' scores, happily married couples could be discriminated from unhappily married couples with 85–95% accuracy. These results were cross-validated with a second sample. Using regression analysis, it was clearly demonstrated that background factors account for little of the variance in discriminating happy from unhappily married couples compared to their relationship dynamics, i.e., scale scores. All ENRICH scales except equalitarian roles proved significant, indicating the validity of a multidimensional inventory.     

AIDS as a political issue: working with the sexually prostituted in the Philippines

An estimated 200,000-500,000 men, women, and children work in prostitution in the Philippines in a variety of venues, including brothels, nightclubs, pubs, massage parlors, and other legitimate entertainment establishments. Few, however, are voluntary prostitutes. Many people who work as prostitutes have been recruited from the provinces, kept in conditions similar to slavery, and forced to earn money from prostitution to pay for their transportation, board, and lodging. Many prostitutes work in urban centers and tourist resorts in the countryside. During the 1970s, then President Ferdinand Marcos promoted tourism as a major industry, effectively marketing attractive Filipinas to tourists. Sex tourism has flourished in the country ever since. Thousands of prostitutes are also located in Olongapo and Angeles, 2 cities north of Manila, from where they serve the sexual desires of US military personnel. The presence of US military personnel in the Philippines has always been associated with prostitution. The country's social hygiene centers, prostitutes in Manila and Davao, and AIDS education are briefly discussed.     

Student desires for a university drug education program

A questionnaire was designed to determine the type of drug education program most desired by undergraduate students attending a major university. The survey was to provide the basis for a comprehensive drug education program. The 101 item questionnaire elicited responses from 656 undergraduates in categories ranging from knowledge base to credible information sources. The analysis of student desires as they relate to program design is included in this article. The students strongly believed the university should provide a drug education program. In particular they desired a credit course dealing with both drugs and alcohol. They also wanted regularly published articles on drugs in school publications. The most credible knowledge sources were PhDs and MDs. Students also wanted contact with former drug users. More than half the students believed that values clarification and "coping skills" training would decrease their drug use. In general more women than men were likely to utilize such resources.