Child health,breast-feeding,and survival in Malaysia: a random-effects logit approach

This study examines the possibility that estimation of the effect of breast-feeding on infant survival is affected by selection bias, in that children who are healthier at birth may be more likely to be breast-fed. Data are from the 1976 Malaysian Family Life Survey. "Ordinary logit models for breast-feeding and survival are estimated, and the results suggest that selection is indeed present. For example, children of higher birth weight appear to be more likely to be breast-fed and likely to survive. In addition, weight at birth and the duration of breast-feeding appear to be linked." Using birth weight as an indicator for the child's health, the authors conclude that "the direct influence of breast-feeding on survival remains of overwhelming importance even after corrections for selection bias are made."     

Computer support of placement planning: the use of expert systems in child welfare

Computers have become commonplace in nearly every setting, from home to office. In addition to their usefulness for managerial tasks, they have the potential to aid the primary decision-making tasks of professional social service workers. The benefits and background of such "expert systems" are explored, and the structure of one experimental consulting program for child welfare workers, PLACECON, is presented.     

How bad can a voting location be

Two questions concerning the location of a single facility by a voting process are investigated for transportation networks:

- What is the maximum number of customers located on the network preferring some rival point over a voting solution?

- How does the average distance of the customers to the facility increase when a voting location instead of a Weber location is chosen for the facility?

Complete answers are given for general networks and for certain planar networks, viz., the so-called generalized cacti.     

Selectivity,adaptation, or disruption? A comparison of alternative hypotheses on the effects of migration on fertility: the case of Brazil

This study, based on Brazilian data from 1976, compared the fertility of migrants and stayers at both origin and destination areas. Observed patterns of fertility differentials were then analyzed in terms of 4 hypotheses of fertility behavior focused on processes of socialization, adaptation, selectivity, and disruption. In the study sample, 31% of migrants moved from rural to urban areas, 45% of moves were between urban areas, and 20% of moves were between rural areas. Among rural-to-urban migrants, only 1/3 moved from traditional to modern regions. To uncover the main patterns of migrant and stayer fertility differentials in the study population, the major flows of migrants by origin and destination were disaggregated by recency of migration, education, and age. The overall conclusions were as follows: 1) rural-urban migration flows need to be disaggregated into various modern/traditional cross-classifications (e.g., modern-rural, traditional-urban, frontier-urban) and greater emphasis needs to be placed on rural-urban, urban-urban, and rural-rural flows; 2) no robust quantitative measures of migrant-stayer fertility differentials held across migrant groups, implying that migrants differing in terms of age, education, origin, and destination are likely to behave in significantly variable fashion with regard to stayer standards of fertility behavior; 3) migrant groups with overall lower fertility levels, such as the young and better educated, are less likely to experience significant fertility reduction to bridge the origin/destination fertility gap; 4) rural-to-rural migrants do not appear to experience any lasting fertility reduction even when they move to areas with lower overall fertility rates; 5) urban-to-rural migrants tend to bridge a larger fraction of the uphill fertility gap than rural-to-urban migrants; and 6) there was evidence of partial adaptation for most migrant categories once disruption effects disappear and evidence consistent with the socialization hypothesis (no fertility reduction for at least 1 generation) was apparent for migrants originating in the least developed parts of Brazil, the frontier region, and the traditional-rural region.     

视觉现代化——现代艺术背后的人类视觉观念(1)

20世纪初所发生的“视觉现代化”(modernising vision)转向源于自19世纪以来传统的视觉概念所发生的深刻变化。它旨在将人们从过时的观看习惯中解放出来,视觉的本质不应主要被理解为给定可见世界的机械再现模式,而应该从根本上被理解为由文化构造的、具有历史多样性的感知数据的生产性过程。现代艺术试图通过艺术品本身来创造一种现代化的视觉形式,艺术作品被定义为实现视觉现代化的手段或工具,画家试图用艺术来表达一种新的视觉观——观看中充斥着时间的流动,而绝不仅是一个明确的视觉顺序的实现;观看不是一个视觉固定化过程,而是更加有意识地、集中地观察世界。从丢勒式的空间中心透视观到塞尚式的时间和空间相结合的多重透视观,后者更加强调了观者的参与和观看的过程,这种观看方式的变化也是人与世界关系的变化。视觉现代化的探讨在今天仍然具有重要的意义⁽²⁾。