Nutritional Status from 1 to 15 Years and Adolescent Learning for Boys and Girls in Ethiopia,India, Peru,and Vietnam

Population Research and Policy Review - There has been little examination of: (1) associations of early-life nutrition and adolescent cognitive skills, (2) if they vary by gender, (3) if...     

Tests concerning two non-isotropic principal components

Kshirsagar & Gupta (1965) proposed test criteria for testing the null hypothesis that a p x p covariance matrix, with known smallest latent root of multiplicity p-2. has its two non-isotropic principal components in specified directions. Simula-tion results indicate that the power functions of these test criteria lack some desirable properties. However, another statis-tic discussed by Kshirsagar and Gupta is shown to have a power-function which performs quite well. The situation in which the smallest latent root of multiplicity p-2 is unknown, is also considered.     

Some tests for the allometric extension model in regression

The allometric extension model is a multivariate regression model recently proposed by Tarpey and Ivey (2006 Tarpey, T., Ivey, C.T. (2006). Allometric extension for multivariate regression. J. Data Sci. 4:479–495. [Google Scholar]). This model holds when the matrix of covariances between the variables in the response vector y and the variables in the vector of regressors x has a particular structure. In this paper, we consider tests of hypotheses for this structure when (y′, x′)′ has a multivariate normal distribution. In particular, we investigate the likelihood ratio test and a Wald test.     

Sustainable Development and Capabilities for the Polar Region

The paper develops a sustainable development framework for individual and collective capabilities in mixed subsistence and wage-based economies. We apply this framework to such regions of the Arctic and evaluate interactions and conflicts between two sectors of the mixed economy and between current and future generations of Arctic inhabitants. A recent Arctic Social Indicators Report published by the Arctic Human Development Report (AHDR) Task Force recognizes the importance of the mixed economy in the Arctic and aims to integrate collective assets, as well as individual assets in order to understand the human development in the Arctic. Yet due to its concerns of comparability of social development and data availability across the whole Arctic region (of which some parts do not have the similar population structure), its proposed indicators are not capable of covering the social development of predominantly indigenous regions of the North. We emphasize the importance of tracking collective capabilities, as well as individual capabilities to sustain community development. In addition we suggest that environmental sustainability, which is ignored by the AHDR Task Force, has to be integrated with social development as environmental deterioration significantly influences the social well-being and cultural stability of traditional inhabitants of the Arctic. We critically review the proposed indicators of the AHDR Task Force and make supplementary and alternative suggestions.     

Reduced-rank estimation of the difference between two covariance matrices

We consider m×m$m\times m$ covariance matrices, _Σ1${\Sigma }_1$ and _Σ2${\Sigma }_2$, which satisfy _Σ2-_Σ1=Δ${\Sigma }_2-{\Sigma }_1=\Delta$, where Δ$\Delta$ has a specified rank. Maximum likelihood estimators of _Σ1${\Sigma }_1$ and _Σ2${\Sigma }_2$ are obtained when sample covariance matrices having Wishart distributions are available and rank(Δ)$\text{rank}(\Delta )$ is known. The likelihood ratio statistic for a test about the value of rank(Δ)$\text{rank}(\Delta )$ is also given and some properties of its null distribution are obtained. The methods developed in this paper are illustrated through an example.     

Comparison of some goodness of fit tests for a single non-isotropic hypothetical principal component

Kshirsagar (1961) proposed a t e s t criterion for the null hypothesis that a covariance matrix with known smaller latent root of mu1tip1icity p?1 has its single non-isotropic principal component in a specified direction. It is shown that the power function of this criterion lacks some desirable properties. Another test criterion is proposed. The case in which the covariance matrix has an unknown smaller latent root of multi-plicity p?1 is also investigated.     

Psychological trauma from the perspective of medical history: from Paracelsus to Freud

Psychological traumatisation, as we understand it today, was—in terms of the history of ideas—anticipated by various approaches which have had a lasting impact on modern psychiatry, psychotherapy, and psychosomatic medicine. On the one hand, there is the traditional concept of possession and exorcism with its impressive psychodynamics. On the other hand, there is the theory of the imagination, of an illusion in the sense of a pathogenic infection. Especially the pathological teachings of Paracelsus (sixteenth century) and Johann Baptist van Helmont (seventeenth century)—the latter having advanced the former’s alchemist approach—demonstrate the extent to which demonological, parasitological, and psychological ideas were amalgamated in their “ontological” notion of a disease. Only the introduction of hypnotism in the middle of the nineteenth century made possible a psychological or psychodynamic understanding of psychological trauma in the modern sense. Hypnotism was striving to strictly dissociate from the magical and natural philosophical speculations of mesmerism and its theory was quite compatible with the model representations of scientific medicine. Sigmund Freud was able to tie in his ideas of hysteria and neurosis with this concept and especially to define repression of (infantile) sexuality as the cause of a culturally ineluctable psychological trauma. Finally, a brief survey of medical history is given to explore artificial trauma as a healing factor.     

Testing the equality of correlation matrices when sample correlation matrices are dependent

We consider the situation in which a 2m×2m$2m\times 2m$ correlation matrix is naturally partitioned into a 2×2$2\times 2$ form, where each submatrix is m×m$m\times m$ and we wish to test for the equality of the two correlation matrices appearing on the diagonal of the partitioned form. Standard tests for the equality of correlation matrices do not apply since the corresponding sample correlation matrices are correlated. We obtain Wald statistics under the assumption of multivariate normality as well as extensions that apply to elliptical distributions.     

Going Back Part-time: Family Leave Legislation and Women’s Return to Work

Using a multinomial logit model with data from the Survey of Income and Program Participation, this paper tests whether the implementation of the Family and Medical Leave Act (FMLA) is associated with an increase in return to work at part-time status among first-time mothers working full-time during their pregnancy. I find a statistically significant trend of increasingly higher odds of returning to work at part-time status relative to return at full-time status, beginning in 1993 (the year in which the FMLA is implemented). Furthermore, an additional week of either state or federal leave is significantly associated with a higher odds of return at part-time status. This article provides evidence that job protection and leave legislation may help facilitate higher levels of labor force participation among women with small children, through more flexible work arrangements.     

A note on the critical values used in stepwise tests for multiplicative components of interaction

A result is presented concerning the null distribution of a statistic used to determine the number of multiplicative components in a fixed two-way model. This result suggests critical values which are compared with previously suggested critical values.