Nonparametric Regression with Sample Design Following a Random Process

Nonparametric regression is considered where the sample point placement is not fixed and equispaced, but generated by a random process with rate n. Conditions are found for the random processes that result in optimal rates of convergence for nonparametric regression when using a block thresholded wavelet estimator. Previous results on nonparametric regression via wavelets on both fixed and random sample point placement are shown to be special cases of the general result given here. The estimator is adaptive over a large range of Hölder function spaces and the convergence rate exhibited is an improvement over term-by-term wavelet estimators. Threshold selection is implemented in a data-adaptive fashion, rather than using a fixed threshold as is usually done in block thresholding. This estimator, BlockSure, is compared against fixed-threshold block estimators and the more traditional term-by-term threshold wavelet estimators on several random design schemes via simulations.     

Dilation-Invariant Wavelet Estimation

A wavelet method is proposed that reduces function estimation error and provides smooth reconstructions, while still estimating jumps in the function well. It is based on analyzing multiple dilated versions of the sampled function. In simulation studies, the estimator exhibits low mean squared errors without sacrificing smoothness or jump detection ability when compared to other wavelet methods.     

Seroadaptive Strategies of Vancouver Gay and Bisexual Men in a Treatment as Prevention Environment

British Columbia’s treatment as prevention policy has provided free access to highly active antiretroviral therapy (HAART) to all HIV-positive provincial residents since 1996. One outcome is an increase in HIV-positive gay and bisexual men (GBM) with suppressed viral loads. Previous cross-sectional analyses indicated that some Vancouver GBM now recognize condomless anal sex with men on HAART who report a suppressed viral load as a seroadaptive strategy. To test the hypothesis that this new strategy, termed viral load sorting (VLS), is recognized and used among by GBM in the Momentum Health Study, we analyzed longitudinal data for HIV-negative/unknown (n = 556) and HIV-positive (n = 218) serostatus participants. Analyses indicated that both groups reported VLS, and that serostatus and Treatment Optimism Scale scores were significant determinants in frequency and use. Results exemplify the medicalization of sex and Rogers’ Diffusion Of Preventative Innovations Model, and they have important implications for HIV research and GBM sexual decision-making.     

The paradox of illicit economies: survival,resilience, and the limits of development and drug policy orthodoxy

ABSTRACT

The illicit drug crops opium and coca are conventionally regarded as sources of instability, an ‘evil’ that breeds fragility and violence. Fragile states are supposed to be most vulnerable to their production and consequent harms. Yet by looking into the local contexts of the world’s leading opium and coca producers – Afghanistan, Myanmar, Colombia and Bolivia – these illicit crops are found to also be sources of stability, even drivers of economic growth. They enable marginalized communities and territories abandoned by the state to be reinserted into national and global markets. Within so-called ‘fragile’ and conflict-affected areas are displaced and dispossessed households adopting innovative and unorthodox strategies for coping and survival in changing and insecure environments. This paper maps out an approach, useful for examining the resilience that has emerged amidst violence and uncertainty in illicit-crop-producing territories, and which can hopefully tackle the continuing disconnect between drugs and development policy.     

Corporate social responsibility,financial performance and risk in times of economic instability

Journal of Management and Governance - This article examines the relationship between the social performance of companies and their financial performance, analyzed from the systematic risk...     

Type of Health Facility and Utilization of Antenatal Care Services Among Ghanaian Women

This study examined if differences exist in the number and timing of antenatal care (ANC) visits for users of public and private health care facilities in Ghana. Also, the study explored if such variations could be attributed to health-provider factors or the selective socioeconomic characteristics of the users. Data were drawn from the recently collected Ghana Demographic and Health Survey and from a representative sample of t 2135 women who attended antenatal care in a health facility 6 months preceding the survey. Random-effects Poisson and logit models were employed for analysis. Results showed statistically significant differences between users of private and public health facilities for number of ANC visits, but not for the timing of such visits. Although some health-provider factors were significantly associated with ANC visits, these factors did not explain why users of private health facilities had significantly higher number of ANC visits than users of public health facilities. Differences in ANC visits for both private and public health facilities were rather explained by the selective socioeconomic characteristics of the users, especially as wealthy and educated women patronized private health care than poorer and uneducated women. The study concludes that Ghanaian women attending private health facilities may not have improved access to antenatal care compared to those attending public health facilities, and adds to the emerging body of literature that questions private health care in sub-Saharan Africa as more effective than public health care.