Stratification in college entry and completion

This paper examines stratification of opportunities in college access and completion. Using propensity score methods, we investigate two comparisons: (1) four- versus two-year public colleges and (2) private versus public two-year colleges. While previous research finds lower degree completion in two-year than in four-year public colleges, the comparability of students is doubtful. This paper re-considers the public four-year college effect, but for similar students and additional relevant outcomes. The second comparison is a new one. Though recruiting similar students as public two-year colleges, private two-year colleges use different organizational procedures, and we find that they have a different impact on comparable students’ degree completion. We speculate about the reasons for these differences and whether they suggest potential benefits of adapting these procedures for public two-year colleges.     

Distinguishing Mother–Infant Interaction From Stranger–Infant Interaction at 2, 4, and 6 Months of Age

Observers watched videotaped face‐to‐face mother–infant and stranger–infant interactions of 12 infants at 2, 4, or 6 months of age. Half of the observers saw each mother paired with her own infant and another infant of the same age (mother tapes) and half saw each infant paired with his or her mother and with a stranger (infant tapes). Observers were asked to judge which was the mother–infant dyad in each pair. Observers' accuracy improved as infants aged and was above chance for both mother and infant tapes when infants were 6 months. Differences between mother–infant and stranger–infant dyadic communication patterns also emerged as the infants aged. At 6 months, mother–infant dyads had more symmetrical communication and less asymmetrical communication than stranger–infant dyads.     

Working with young people from refugee backgrounds in Australia

Social workers who are new to working with young people who are refugees may feel overwhelmed, out of their depth and inclined to defer to powerful psychiatric discourse. Arguing a role for social work engagement with young people as they face the personal, social, communal, cultural, political and economic challenges of settlement, this paper proposes a reflexive, deconstructive and dialogical approach within a broadly ecological model. All settlement tasks require mediation through the powerful discourse (language, values, constructs, social practices) of both the young person's own community and those of the new context. Creating spaces where young people can identify and negotiate the forces vying to shape them underpins and complements the urgent task of combating ethnocentricity in Australian institutions.     

Classification of cyclical time series using complex demodulation

A new and innovative procedure based on time varying amplitudes for the classification of cyclical time series is proposed. In many practical situations, the amplitude of a cyclical component of a time series is not constant. Estimated time varying amplitudes obtained through complex demodulation of the time series are used as the discriminating variables in classical discriminant analysis. The aim of this paper is to demonstrate through simulation studies and applications to well-known data sets, that time varying amplitudes have very good discriminating power and hence their use in classical discriminant analysis is a simple alternative to more complex methods of time series discrimination.     

提取剂对紫薯花青素提取效果的影响及pH响应

花青素,是一种天然水溶性色素,因其对环境友好、安全无毒,且对pH变化敏感的特点,在智 能包装领域展现了独特的研究价值。以紫薯为原料,通过保持提取剂的总体积不变,改变提取剂中冰醋 酸和无水乙醇的体积比的方法,研究了提取剂中不同冰醋酸和无水乙醇的体积比对花青素提取效果的影 响,并分析了不同pH值下花青素溶液的显色反应。结果表明,不同配比的提取剂对紫薯中提取花青素有 较大影响。在冰醋酸和无水乙醇体积一定的条件下,通过紫外-可见吸收光谱、pH示差法等分析发现,冰 醋酸和无水乙醇的体积比为1:1时提取的花青素含量最高,显色效果明显。