AN EXACT CONDITIONAL TEST FOR COVARIANCE SELECTION MODELS

An exact conditional test is developed for testing the absence of an edge in a graphical covariance selection model and is shown to be equivalent to a test based on the partial correlation coefficient. An example is given.     

Life-threatening disability in adolescence: Adjusting to a limited future

This paper describes a medical social worker's efforts over one and a half years to help a client adjust to a neurological disorder. Prior to social work services, the young woman had never discussed her disability, which began in adolescence, with anyone outside the family, and communication within the family was seriously compromised by their perception of disability as a stigma. Lacking the opportunity to mourn the loss of her physical abilities, she became isolated and depressed, and acted out aggressive thoughts and fantasies within the family system. Social work intervention helped the client to re-work the original trauma of diagnosis, which led to the development of a healthier defensive structure and new coping mechanisms.     

实现可持续发展的障碍:欧洲和加拿大对高等教育的认识

“可持续发展”这个说法本身具有多种含义。在高等教育中 ,它被用来促进现有的政治、经济和官僚制度的延续。不过 ,它也被用于描述一种使高等教育机构对社会和环境负起更多责任的运动。后者正是本文所要讨论的问题。大学和其他高等教育机构应该把它们所讲授的内容付诸实践———从有关伦理道德和社会行为的概念到对平等和性别的看法。在大学需要注意的问题中 ,特别应该强调可持续发展问题。因为可持续发展不仅包含了上述伦理道德和社会行为方面的问题 ,而且要求优良的管理 ,并鼓励优良的学术实践。实现可持续发展的道路并非一帆风顺 ,而需要…     

EFFICIENT USER CHARGES IN A RENT-SEEKING MODEL

This paper examines efficient user charges on governmentally provided facilities in the presence of rent seeking. We find that the efficient user charge depends upon the relative slopes of the demand curve for the use of the facility and the corresponding marginal cost curve, as well as the level of rent seeking over the revenue raised. Except for a special case, the efficient user charge is found to differ from the charge indicated by the intersection of demand and marginal cost curves. Examples show that actual user charges on government facilities are often set at inefficient levels.     

Simulation study of confidence regions for canonical variate analysis

Canonical variate analysis often involves the construction of confidence regions round points representing group means in a 2-dimensional plot. Traditionally circles have always been constructed, but some authors have recently advocated ellipses as being more appropriate. This paper describes a Monte Carlo study investigating the effect of a range of factors on the inclusion rates of true population means within both types of region for normal data. The traditional circles do not perform too badly within a restricted range, but they are nearly always under-included. The ellipses usually have higher inclusion rates, and so are often closer to the nominal rate, but are sometimes over-included.     

HIGH SCHOOLS AND CRIME: A REPLICATION

Using Cleveland data, we replicate Roncek and LoBosco's study of the effect of proximity to San Diego's high schools on crime in their surroundings. We also examine a major alternative hypothesis whether having other non-residential land uses in the schools' surroundings accounts for crime in these areas. Our findings closely parallel theirs. Proximity to public high schools only increases crime on city blocks which are immediately adjacent to the schools. Second, the size of a school's enrollment is not important for explaining crime in its surroundings. The analysis of non-residential effects supports Roncek and LoBosco's claim that crime effects are due solely to the presence of public high schools, although other land uses affect crime near private high schools. While there are differences in the exact magnitudes of the effects, the substance of their findings for San Diego generalizes well to a very different city. More generally, we argue that Wirth's early arguments about the effect of urbanism on impeding social control can be extended to the residential areas within the city.