Linearly Independent,Orthogonal, and Uncorrelated Variables

Linearly independent, orthogonal, and uncorrelated are three terms used to indicate lack of relationship between variables. This short didactic article compares these three terms in both an algebraic and a geometric framework. An example is used to illustrate the differences.     

Neural Network Simulation of Infant Familiarization to Artificial Sentences: Rule‐Like Behavior Without Explicit Rules and Variables

A fundamental issue in cognitive science is whether human cognitive processing is better explained by symbolic rules or by subsymbolic neural networks. A recent study of infant familiarization to sentences in an artificial language seems to have produced data that can only be explained by symbolic rule learning and not by unstructured neural networks (Marcus, Vijayan, Bandi Rao, & Vishton, 1999). Here we present successful unstructured neural network simulations of the infant data, showing that these data do not uniquely support a rule‐based account. In contrast to other simulations of these data, these simulations cover more aspects of the data with fewer assumptions about prior knowledge and training, using a more realistic coding scheme based on sonority of phonemes. The networks show exponential decreases in attention to a repeated sentence pattern, more recovery to novel sentences inconsistent with the familiar pattern than to novel sentences consistent with the familiar pattern, occasional familiarity preferences, more recovery to consistent novel sentences than to familiarized sentences, and extrapolative generalization outside the range of the training patterns. A variety of predictions suggest the utility of the model in guiding future psychological work. The evidence, from these and other simulations, supports the view that unstructured neural networks can account for the existing infant data.     

Saints or Sinners: Sociobiological Theories of Male Homosexuality

In response to Christian conservative political action, some gay rights advocates have embraced a biological argument. The argument maintains that because homosexuality may have a biological basis, homosexuals should be protected from discrimination. This essay questions the efficacy of this argumentative strategy. The essay demonstrates that biological theories about male homosexuality may not facilitate the efforts of gay rights advocates. In fact, the sociobiological theories analyzed in this essay represent male homosexuality as a state of effeminate pathology. Furthermore, because these sociobiological theories are underdetermined, they are particularly vulnerable to political manipulation. For these reasons, sexual minorities should be cautious about embracing biological arguments in order to secure greater social and political freedoms.     

The Relationship between Social Defiance,Vindictiveness, Anger,and Brain Morphology in Eight‐year‐old Boys and Girls

The goal of this study is twofold: (1) to assess brain anatomical differences between children meeting diagnostic criteria for oppositional defiant disorder (ODD) and healthy controls, and (2) to investigate whether morphological brain characteristics associated with ODD differ in boys and girls. Eight‐year‐old participants (N = 38) were scanned using magnetic resonance imaging. ODD symptoms were assessed using the Dominic‐R interactive. In ODD participants, we observed a significant reduction of gray matter density in the left orbitofrontal cortex—a prefrontal region that plays a pivotal role in emotional self‐regulation and impulse control—and, conversely, an increase in the left temporal area—an area that has been associated with aggressive, impulsive, and antisocial personality. Furthermore, ODD boys showed a reduction of both gray matter density in the left orbitofrontal cortex and of white matter density in the left superior frontal area. The structural abnormalities found in the present study, in particular, the correlation between ODD symptoms and reduction of gray matter density in the left orbitofrontal cortex, may present some evidence for the existence of neuropathology associated with ODD symptoms during childhood. Furthermore, our findings indicate morphometric differences between boys and girls with ODD, which may be associated with gender differences in social behavior in children showing ODD symptoms.     

香港对新移民的管理和安置

与复杂的跨国网络与跨界互动相比,公民身份却划分了清晰的边界.香港回归中国主权后,对其公民身份的类别划分带来了极大的挑战.依照香港基本法中对居留权的定义,很大一部分--近一百六十七万人--可以享有这个权利,反映出香港与内地的跨界社会关系有着复杂历史.尽管香港与内地的社会和经济高度统一,但其边界仍然严格限制了人口从内地向香港流动.这种既统一又分离的状况导致了一种复杂的对立,部分地反映在关于居留权的争论.即使那些已经成功移民香港的内地居民也面临着各种挑战,其中最严峻的是怎样在香港这样一个住房价格最高的城市中获得可以负担的住所.因为新移民无法申请公营房屋,但这些房屋却占香港房屋总数的一半.而其私人住房的价格又是世界上最贵的.     

Returns to education in the Irish youth labour market

Using data from two large-scale household surveys in 1987 and 1994, we estimate wage equations which show substantial increases in returns to university education for young Irish workers over the period, despite the exceptional increase in numbers with these qualifications. Returns to non-degree third level certificates and diplomas fell in relative terms, but returns to qualifications obtained by those leaving school at about 16 years of age rose. We argue that the increased return to university education primarily reflects the generalised shift in demand towards skilled labour internationally and the open nature of the Irish labour market. However, a floor may have been placed under earnings for low-skilled youth by the increased generosity of income support available to them. Received: 29 December 1997/Accepted: 7 August 1998     

Forecasting the Population of Census Tracts by Age and Sex: An Example of the Hamilton–Perry Method in Action

Small area population projections are useful in a range of business applications. This paper uses a case study to show how this type of task can be accomplished by using the Hamilton–Perry method, which is a variant of the cohort-component projection technique. We provide the documentation on the methods, data, and assumptions used to develop two sets of population projections for census tracts in Clark County, Nevada, and discuss specific factors needed to accomplish this task, including the need to bring expert judgment to bear on the task. Our experience suggests that the Hamilton–Perry Method is an important tool and we advise considering it for small forecasting needs in the private sector.     

Robust permutation tests for two samples

We consider robust permutation tests for a location shift in the two sample case based on estimating equations, comparing the test statistics based on a score function and an M-estimate. First we obtain a form for both tests so that the exact tests may be carried out using the same algorithms as used for permutation tests based on the mean. Then we obtain the Bahadur slopes of the tests in these two statistics, giving numerical results for two cases equivalent to a test based on Huber scores and a particular case of this related to a median test. We show that they have different Bahadur slopes with neither exceeding the other over the whole range. Finally, we give some numerical results illustrating the robustness properties of the tests and confirming the theoretical results on Bahadur slopes.