LAND AND ASSET SIZE, STRUCTURE AND DISTRIBUTION AND THE LINKS TO INCOME IN THREE DRYLANDS

At a late stage in preparing this work, we felt responding to the view of all partners that, before analyzing the consequences of asset situations for fertility, migration or environment, we should present, and to some extent explain, some facts about the size, composition, and distribution of assets for the three countries. This paper presents some general contextual evidence, and some main results for South Africa. Work is in progress in the India data, and will be undertaken later for Botswana.International Development,

A synchronous program algebra: a basis for reasoning about shared-memory and event-based concurrency

This research started with an algebra for reasoning about rely/guarantee concurrency for a shared memory model. The approach taken led to a more abstract algebra of atomic steps, in which atomic steps synchronise (rather than interleave) when composed in parallel. The algebra of rely/guarantee concurrency then becomes an instantiation of the more abstract algebra. Many of the core properties needed for rely/guarantee reasoning can be shown to hold in the abstract algebra where their proofs are simpler and hence allow a higher degree of automation. The algebra has been encoded in Isabelle/HOL to provide a basis for tool support for program verification. In rely/guarantee concurrency, programs are specified to guarantee certain behaviours until assumptions about the behaviour of their environment are violated. When assumptions are violated, program behaviour is unconstrained (aborting), and guarantees need no longer hold. To support these guarantees a second synchronous operator, weak conjunction, was introduced: both processes in a weak conjunction must agree to take each atomic step, unless one aborts in which case the whole aborts. In developing the laws for parallel and weak conjunction we found many properties were shared by the operators and that the proofs of many laws were essentially the same. This insight led to the idea of generalising synchronisation to an abstract operator with only the axioms that are shared by the parallel and weak conjunction operator, so that those two operators can be viewed as instantiations of the abstract synchronisation operator. The main differences between parallel and weak conjunction are how they combine individual atomic steps; that is left open in the axioms for the abstract operator.Comment: Extended version of a Formal Methods 2016 paper, "An algebra of synchronous atomic steps

Validation of the Connor Davidson Resilience Scale (Cd-Risc) as Applied within the Thai Context

This study evaluated the psychometric properties of the Thai version of the Connor Davidson Resilience Scale (CD-RISC), a 25-item self-report questionnaire developed to measure resilience. This was achieved by testing the factor structure of the CD-RISC when applied to a non-clinical sample of Thai adults. Exploratory factor analysis identified three resilience factors: personal competence/tolerance of negative affect; support resources; and self-efficacy. Reliability analysis identified a number of items that were not internally consistent and these were deleted from the scale. The final Thai version of the CD-RISC consisted of 18 items, which is shorter than the original 25-item scale. The scale's convergent validity was tested by assessing the scale's relationship with three states of negative affect – depression, anxiety, stress – as measured by the 21-item Depression Anxiety and Stress Scale (DASS-21). Correlation analysis revealed that the three extracted resilience factors of personal competence/tolerance of negative affect; support resources; and self-efficacy are significantly and negatively correlated with the DASS-21 factors of depression, anxiety, and stress. The utility of the CD-RISC as applied within the Thai context is discussed

Occupational Transitions: A Cohort Analysis Of Transitions Between Occupation Classes 1981 To 2006

This paper is limited to presenting an initial look at the New Zealand Linked Census. The intention here is limited to describing the NZ Linked Census, providing an example of how this new dataset can be used in the wider context of labour market themes, and promoting the dataset as a powerful tool for new and ground breaking longitudinal research

Distribution of Stream Macroalgae in Four High Arctic Drainage Basins

Eighty-three stream reaches were sampled from four drainage basins in the central portions of Axel Heiberg and Ellesmere Islands. The stream included small snowmelt tributaries, those flowing through wetlands, pond outflows, glacial meltwaters, and large trunk rivers, some of which had become braided in their lower portions. Larger channels tended to be quite turbid, and macroscopic algae were negligible in these reaches because they lack adequate light and hard substrata for attachment. The overall stream macroalgal flora was relatively small (15 species) compared to that of other regions of the North American tundra. Cyanobacteria and Chlorophyta accounted for all but one species. The most widespread species was the colonial cyanobacterium, Nostoc commune. Only Scytonema mirabile (Cyanophyta) was a new addition to the stream macroalgal flora of arctic North America. The numbers of species per stream reach ranged from 0 to 5, with a mean of 1.3. The amount of stream bottom covered by macroalgae was 0 to 75%, with an average of ca. 5%. Both species number and percent cover per reach are relatively low.On a procédé à des échantillonnages de 83 tronçons de cours d'eau situés dans quatre bassins de drainage au centre de l'île Axel Heiberg et de l'île d'Ellesmere. Les cours d'eau comprenaient de petits affluents alimentés par la fusion nivale, ceux qui traversaient des terres humides, des émissaires d'étangs, des eaux de fonte glaciaires et d'importants cours d'eau principaux, dont certains étaient devenus anastomosés en aval. Les chenaux larges avaient tendance à être relativement troubles et on ne trouvait que peu d'algues macroscopiques dans ces tronçons en raison du manque de lumière adéquat et des substrats de soutien. La flore macroalgale globale des cours d'eau était assez réduite (15 espèces) par rapport à celle d'autres régions de la toundra nord-américaine. Toutes les espèces sauf une appartenaient aux cyanobactéries et aux chlorophycées. L'espèce la plus répandue était la cyanobactérie coloniale, Nostoc commune. Seule Scytonema mirabile (cyanophycée) était une nouveauté dans la flore macroalgale de l'Arctique nord-américain. Le nombre d'espèces par cours d'eau allait de 0 à 5, avec une moyenne de 1,3. De 0 à 75 p. cent de la superficie du fond des cours d'eau était couverte par les macroalgues, avec une moyenne d'environ 5 p. cent. Le nombre d'espèces comme le pourcentage de leur couverture par tronçon étaient relativement bas

An All Too Real Neverending Story: Federal Income Tax Complexity

This research effort extends the work of Rosacker and Davies (1997) to re-validate their tax complexity model. The empirical outcomes of the current study permit a comparative assessment of tax complexity across time while additionally allowing for the immediate consideration of several significant tax reforms enacted within the Tax Cuts and Jobs Act of 2017. The primary research question is whether the model helps inform tax policy choices targeted at decreasing tax complexity through a focus on the enacted tax reforms, a critical objective specified for the original research effort. This study enhances the literature by assessing and comparing federal income tax complexity under prior, existing, and subsequent tax systems. A complexity measurement model has been created utilizing data developed under the IRS, allowing the investigation of a database created annually by the IRS

Model-checking tool support for quantitative risk analysis and design for safety

This paper is concerned with quantitative analysis of tolerance of sensor hardware failures by control system software. The aim is to help the system designer evaluate the efectiveness of risk reduction measures in the system design. This paper proposes an approach for using stochastic model checking to evaluate how likely a given sensor failure mode is to lead to a hazardous system failure, taking control logic and sensor-update timing failures into account. In particular we propose two complementary techniques: one for examining short- term consequences of component failures and the other for examining more subtle longer-term consequences (so-called hidden failures). The techniques overcome scaling issues and yield valuable insights into the relative merits of dierent design decisions. The PRISM model checker is used for stochastic analysis of Continuous Time Markov Chain (CTMC) system models. The approach is illustrated on a case study from manufacturing, involving an industrial metal Press. Although relatively simple, the Press exhibits a wide range of different behaviours, including hidden failures and subtle race conditions

Price Comparison, Price Competition, And The Effects Of ShopBots

Two ShopBots were used to determine high-to-low price dispersion for identical models of 25 consumer durables, in 2007 and again in 2011, revealing substantial but declining price dispersion ratios. A survey of 1,135 American online shoppers revealed their dependence on ShopBots and frequency of other online shopping actions. Typical respondent reported they "very often" used search sites to locate what they wanted. Nearly 30 percent used the most often named price comparison site, Yahoo! Shopping, in the past year, suggesting substantial potential for future price rationalization. Several customer relationship management tools online merchants might use to avoid the resulting direct price competition are discussed. Finally, the impact of m-commerce, tablets, and apps on online price comparison behavior is explored