Model Selection Using Conditional Densities

In this article we propose a new method to select a discrete model f(x; θ), based on the conditional density of a sample given the value of a sufficient statistic for θ. The main idea is to work with a broad family of discrete distributions, called the family of power series distribution, for which there is a common sufficient statistic for the parameter of interest. The proposed method uses the maximum conditional density in order to select the best model.

We compare our proposal with the usual methodology based on Bayes factors. We provide several examples that show that our proposal works fine in most instances. Bayes factors are strongly dependent on the prior information about the parameters. Since our method does not require the specification of a prior distribution, it provides a useful alternative to Bayes factors.     

高校文学课程立体化教学改革探索

近年来我国高校文学课程教学改革一直呼声不断，但效果甚微。其主要原因是理念谈得多，而把理论转化为实践，摸索出的可操作性内容较少。据此，笔者提出文学教学改革具体实施方略。呼吁突破传统教学方法，摆脱教材束缚，增加课堂灵活度；提倡课堂教学回归文学性，重视学生实践能力培养，将教学内容划分板块，使其层次化；着力延伸课外教学，加强学生自主学习性，使课外教学丰富化、多样化；完善考核评价机制，提高教学实施效果，最终实现立体化教学新模式。     

Persistence and desistance in heavy cannabis use: the role of identity,agency, and life events

Many cannabis users ‘mature out’ of their drug use, and factors of cannabis use cessation have been identified. However, very little in-depth knowledge is available about the mechanisms underlying this phenomenon. Criminological studies have gained interesting insights in desistance from crime, yet these perspectives are rarely used in drug research. This qualitative, three-year longitudinal study explored the processes involved in desistance from frequent cannabis use for young adults. Using a narrative approach, desisters (frequent users who successfully quit their cannabis use) and persisters (frequent users with a persistent desire and unsuccessful attempts to quit) were compared. In the course of the study, desisters mainly exhibited increasing agency and goal setting, established strategies to achieve these goals, and could envision another self. Desistance was generally induced by life events that became turning points. Persisters experienced largely similar events, but lacked goals and strategies and held external factors responsible for their life course and failed quit attempts. Identity change is at the core of desistance from frequent cannabis use, and the meaning-giving to life events and experiences is essential. Agency is a necessary ingredient for desistance, develops over time and through action, and leads to a new drug-free identity with desistance in turn increasing agency.     

Income Inequality in Latin America: Data Challenges and Availability

This article discusses the main challenges faced by nowadays researchers when measuring income inequality in Latin America. The discussion is articulated around the two main approaches to summarize the distributional problem: factor and personal inequality. The article underlines the difficulties, mainly imposed by data availability for inequality measurement under both of them. The article proposes specific lines to advance in the improvement of data quality and availability for inequality measurement (and understanding) in the region.     

新中国少数民族题材美术的话语实践

新中国少数民族题材美术创作的产生和发展与中国近现代文化转型时期的文化内部需求密切相关,作为新中国文化史上重要的视觉文本,其创作成果形象地见证了中国近现代文化向多元一体文化格局转化的过程,而其创作历程则是中国美术家立足于本土文化资源,传承与重构中华民族文化脉络,致力于实现文化自主价值,对抗文化"同质化"趋势的话语实践。     

Is Land Grabbing Always What It Is Supposed to Be? Large‐scale Land Investments in sub‐Saharan Africa

The term ‘land grabbing’ has recently attracted widespread, and sometimes agitated, attention, and its literature grows at exponential speed. At the same time, the concept remains little understood concerning both its meaning, magnitude and consequences and even who the grabbers are. Different attempts to define land grabbing appear to reflect ideological lenses and pre‐defined positions rather than a genuine ambition to find out what is actually going on. Based on a comprehensive literature review, this article aims at presenting a more nuanced understanding of this disputed topic and therefore a less biased account of what land‐grabbing and/or private investments in land represent.     

NCWWI Traineeships: A National Cross-Site Evaluation of Child Welfare Stipend Programs for Ethnically Diverse Students

The task of recruiting and retaining ethnically diverse, qualified, and committed social workers in child welfare is challenging. Federal funding supporting BSW and MSW education has been a catalyst for university–agency partnerships across the country. An important goal of these partnerships is to prepare social work students with the knowledge, skills, and competencies for effective child welfare practice. The National Child Welfare Workforce Institute’s innovative child welfare traineeships program prepares students from 12 social work programs around the country. This study focused on diversity, competency attainment, and readiness for the job. Results showed that programs recruited ethnically diverse students, and after receiving child welfare–specific content and hands-on experiences in the field, students felt competent and prepared for child welfare work.     

Pre‐ and Post‐Migration Determinants of Socio‐Cultural Integration of African Immigrants in Italy and Spain

Using a unique dataset (N=2,014), we examine the pre‐ and post‐migration determinants of socio‐cultural integration among first‐generation immigrant groups in southern Europe: Moroccan and Senegalese migrants in Spain, and Egyptian and Ghanaian migrants in Italy. The results of the pooled and immigrant‐group specific regression analyses partly highlight the dominance of pre‐migration factors. Immigrants who were well‐educated and well‐informed prior to migrating and who migrate at a young age, achieve higher levels of socio‐cultural integration. Going against some hypotheses found in the literature, female gender and North African origin have a positive effect on socio‐cultural integration as opposed to male gender and sub‐Saharan origin. With regard to post‐migration factors, occupational status is the main economic determinant of socio‐cultural integration. Interestingly, being employed as such has no significant effect on socio‐cultural integration. This suggests that labour market segmentation and discrimination negatively impact upon socio‐cultural integration. The results also suggest that policies allowing immigrants to benefit from the human capital they carry across borders and achieve upward socio‐economic mobility are likely to enhance their socio‐cultural integration.