The Welfare Enigma: Explaining the Dramatic Decline in Canadians' Use of Social Assistance, 1993-2005

What accounts for the truly remarkable drop in welfare dependency in Canada since the early 1990s? The authors provide a nationwide empirical analysis of the underlying factors, and draw implications for policymakers.social policy, Social Assistance (SA), Employment Insurance

Mobility and Gender at the Top Tail of the Earnings Distribution

The increasing share of the top fractile in the earnings distributions of several Anglo- Saxon heritage economies since the 1970s has been dramatic, and well documented. To date, however, little is known about the socio-economic origins and gender composition of the very top tail in the modern era. This paper takes a first step in filling some of the holes in our knowledge. We use a tax-filer data base for Canada for the period 1983-2003 that contains about eighty million observations. We show first that male earners in the top one thousandth of the distribution come very disproportionately from families with incomes in the top decile. In contrast, individuals in the remaining part of the top centile have more dispersed socio-economic origins. Second we show that female participation in the top fractiles has been very low, and that growth in participation has been slow yet definite. In contrast, female earnings in this echelon are almost on par with male earnings. Third, we show that there is an enormous asymmetry between the genders when it comes to spousal earnings: high-earning women have very high-earning spouses, but not vice versa. ‘Secondary males’ have earnings levels almost ten times as high as ‘secondary females’, suggesting that, even at this extremely elevated earnings level there is truth to the adage about who lies ‘behind’ successful individuals. Finally, it is illustrated that the earnings concentration that has characterised the last three decades did not change with the end of the ‘tech boom’ in the year 2000.

Nonlinear Dimensionality Reduction Methods in Climate Data Analysis

Linear dimensionality reduction techniques, notably principal component analysis, are widely used in climate data analysis as a means to aid in the interpretation of datasets of high dimensionality. These linear methods may not be appropriate for the analysis of data arising from nonlinear processes occurring in the climate system. Numerous techniques for nonlinear dimensionality reduction have been developed recently that may provide a potentially useful tool for the identification of low-dimensional manifolds in climate data sets arising from nonlinear dynamics. In this thesis I apply three such techniques to the study of El Nino/Southern Oscillation variability in tropical Pacific sea surface temperatures and thermocline depth, comparing observational data with simulations from coupled atmosphere-ocean general circulation models from the CMIP3 multi-model ensemble. The three methods used here are a nonlinear principal component analysis (NLPCA) approach based on neural networks, the Isomap isometric mapping algorithm, and Hessian locally linear embedding. I use these three methods to examine El Nino variability in the different data sets and assess the suitability of these nonlinear dimensionality reduction approaches for climate data analysis. I conclude that although, for the application presented here, analysis using NLPCA, Isomap and Hessian locally linear embedding does not provide additional information beyond that already provided by principal component analysis, these methods are effective tools for exploratory data analysis.Comment: 273 pages, 76 figures; University of Bristol Ph.D. thesis; version with high-resolution figures available from http://www.skybluetrades.net/thesis/ian-ross-thesis.pdf (52Mb download

Evidence for Action on HIV Treatment and Care Systems in low and middle-income countries: background and introduction.

Despite the unprecedented scale-up of treatment for HIV in low and middle-income countries over the past decade, 49% of adults and 77% of children in need of HIV treatment still do not have access to it. ART programmes that were initially set up as an emergency response now need to be adapted to ensure that they include all the essential components and are well integrated with other health services; meet the needs of special groups, including children, adolescents, pregnant women and older people; address the mental health needs of HIV-positive people; and monitor as well as report their impact in valid and comparable ways.This supplement is an output from the Evidence for Action on HIV Treatment and Care Systems research programme consortium. Evidence for Action was a 5-year, multidisciplinary research programme, which ran from 2006 to 2011, with partners in India, Malawi, Uganda, Zambia and the United Kingdom.The primary aim of this supplement is to stimulate reflection and provide guidance on what should be in the package of HIV treatment and care systems, as national programmes look to maintain the major advances of the past decade and scale-up treatment to the other 50% of people in need of it

Multi-Brane Worlds and modification of gravity at large scales

We discuss the implications of multi-brane constructions involving combinations of positive and negative tension brane and show how anomalously light KK states emerge when negative tension ''-'' branes are sandwiched between ''+'' branes. We present a detailed study of a ''+--+'' brane assignment which interpolates between two models that have been previously proposed in which gravity is modified at large scales due to the anomalously light states. We show that it has the peculiar characteristic that gravity changes from four dimensional (4D) to 5D at large distances and returns to 4D at even larger scales. We also consider a crystalline universe which leads to a similar structure for gravity. The problems associated with intermediate negative tension branes are discussed and a possible resolution suggested.Comment: 28 pages, 6 figures,references adde

Long-term effects of timber management on marten (Martes americana) habitat potential in an Ontario boreal forest

To evaluate the hypothesis that current forest management practices in the boreal forest are decreasing the quantity and quality of long-term marten habitat, and alternative, more suitable strategies exist, a Geographic Information System (GlS)-based simulation study was initiated to determine the habitat suitability for marten of a boreal forest under various timber management strategies. Two simulation models were used in this study. The first was the Harvest Schedule Generator (HSG), a wood-supply model created at the Petawawa National Forestry Institute (Forestry Canada). The second was a marten Habitat Suitability Index (HSI) model developed for this study. Each of the timber harvest strategies decreased the amount of long-term marten habitat. However, slight decreases in the level of spruce harvest provide significant future increases in suitable habitat. In the short term, delayed harvest of mature black spruce stands provides an improvement in marten habitat suitability. The procedures developed in this study provide valuable quantitative information which can be used to aid in forest management decision making