Positive dependence and monotonicity in conditional distributions

Positively dependent random variables exhibit the property that an extreme value of one of the variables tends to be accompanied by extreme values of the others. In this paper we define two notions of positive dependence which lead to monotonicity theorems for conditional distributions.     

New Estimates and Projections of Population Growth in Pakistan

Pakistan's population growth rate rose steadily from about 2.6 percent per annum in the early 1960s to a high of about 3.5 percent during the late 1980s. Since then it has declined to an estimated 2.1 percent for 2003. Growth rates calculated from the population censuses, which show a very different picture, are distorted by differential accuracy of enumeration. During the period of rising growth rates, fertility was constant at just under 7 children per woman while life expectancy at birth rose by nearly 20 years. Fertility decline began in the late 1980s, bringing the population growth rate down with it. Remarkably, there appears to have been little change in life expectancy over the past 15 years.     

Migrant Indebtedness: Bangladeshis in the GCC Countries

Labour migration affects family economics in at least two ways: one is the outflow of indispensable family resources to meet the expenses incurred in the migration process and the other is the transfer in cash or kind from migrants to their non‐migrating families. This study primarily addresses the former flow, that is sources of funds for migration and resulting migrant indebtedness. Drawing on the experiences of Bangladeshi migrants in the GCC countries, this study explores the economic cost of migration, the extent of migrant indebtedness, and the implications of remittances on migrant families. This research exposes the complexity and multiplicity of the economic costs of migration to the GCC countries and reports that Bangladeshi migration to the Gulf states runs on debt, with migrants and their families indebting themselves in the migration process.     

Integration policy in Singapore: a transnational inclusion approach

A number of models of integration have been developed to highlight the experiences of immigration and integration in the Western world. However, the existing models do not adequately capture the complexities of contemporary international immigration and integration, especially the integration process in the light of migrant transnationalism in Asia. This study examines the models of integration through a case study of Singapore. This paper introduces a new concept ‘transnational inclusion’ to conceptualize Singapore's initiative to embrace its transnational global Singaporeans as well as its transnational immigrants, estimated to make up one-fourth of the total population. The paper shows that a transnational inclusion model of integration can provide better insights into the dynamics of transnationalism and integration in today's complex migration scenario. We point to Singapore's integration approach that regards integrating migrants into the different spheres of the society as a process rather than an end.     

Gays,Guys, and Mchicha Mwiba: Same-Sex Relations and Subjectivities in Dar es Salaam

Drawing on 15 months of fieldwork, this article explores ways in which same-sex relations are perceived and performed in Dar es Salaam, Tanzania. While several different constructions of same-sex sexuality coexist in Dar es Salaam, it is common to conceive of same-sex practicing men as falling into two main categories. Men belonging to each of these differ with respect to the corporeal, gendered, and social positions that are open to them, and typically form dyads across the conceptual boundary of difference that runs between them. The article speaks to the importance of examining sexuality and gender in particular sociocultural settings.     

Asset Ownership and Microloan Repayment: Examining Data from Bangladesh

Employing data for 34,255 loans made by the Bangladesh Rural Advancement Committee (BRAC) to 12,455 repeat borrowers during the 2002–6 period, this article examines the relationship between borrowers' asset holdings and microloan repayment. Estimating a series of binomial probit specifications, it finds a positive relationship between land ownership and loan repayment; however, taken collectively, ownership of non‐land assets diminishes the likelihood of repayment. Influences of specific assets on repayment probabilities vary across asset types: ownership of land, corrugated tin houses, vans and rickshaws increases the likelihood of repayment, while ownership of sewing machines, televisions, radios and bicycles corresponds with a decreased repayment probability.     

Greenhouse gases and green roofs: carbon dioxide and methane fluxes in relation to substrate characteristics

Green roof systems have been increasingly implemented to enhance vegetation cover and associated ecosystem services in urban spaces, with primary goals being the reduction of peak surface runoff, enhanced water quality, and mitigation of urban heat island effects. Recently, green roofs have also received attention as a means to enhance carbon sequestration, but direct measurements of greenhouse gas fluxes from established green roof systems are largely lacking. Here we present observations of CO₂ and CH₄ fluxes from substrates of experimental extensive green roof units that varied in vegetation type (Sedum spp., and a native meadow species mix), substrate depth, substrate type (high vs. low organic matter content), and irrigation. We predicted that substrate CO₂ effluxes would be higher in high-organic-matter substrates and that systems with high organic matter would potentially act as CH₄ sources. Substrate fluxes were low compared to natural soils, with seasonal means ranging from an efflux of 0.1–0.4 µmol CO₂ m^-2.s^-1 and uptake of ~0.00–0.04 nmol CH₄ m^-2.s^-1, with higher fluxes late in the growing season. CO₂ fluxes showed large increases in response to irrigation and were higher from the high-organic-matter substrate and with increased substrate depth. The strength of the CH₄ sink increased in response to prior irrigation treatments, and CH₄ emissions were detected only on low-organic-matter substrates early in the growing season. No effects of vegetation type were detected for either CO₂ or CH₄ flux. Our results indicate that high levels of organic matter in green roof substrates may enhance aerobic soil respiration but are not associated with CH₄ emissions, which instead were only detected in low-organic-matter substrates.

     

Performance of some new preliminary test ridge regression estimators and their properties

The problem of estimation of the regression coefficients in a multiple regression model is considered under multicollinearity situation when it is suspected that the regression coefficients may be restricted to a subspace. We present the estimators of the regression coefficients combining the idea of preliminary test and ridge regression methodology. Accordingly, we consider three estimators, namely, the unrestricted ridge regression estimator (URRE), the restricted ridge regression estimator (RRRE), and finally, the preliminary test ridge regression estimator (PTRRE). The biases, variancematrices and mean square errors (mse) of the estimators are derived and compared with the usual estimators. Regions of optimality of the estimators are determined by studying the mse criterion. The conditions of superiority of the estimators over the traditional estimators as in Saleh and Han (1990) and Ali and Saleh (1991) have also been discussed.