An extension of the block spacial path approach to analysis of the influence of intra and interregional trade on multiplier effects in general interregional input-output models

In a number of recent papers Sonis, Hewings and coworkers have extended spacial path analysis to a block structural context capable of analysing the relationship between direct blocks of influence, such as intra and interregional trade coefficients or demographic-economic interactions, and full model multipliers. The approach makes use of a definition of the direct coefficients block partitioned matrix in terms of simpler matrices each of which is made up of null blocks except for one block column. In the current paper, the underlying technique is extended by making use of an even simpler matrix construction - an "almost null" matrix, defined as null in all partitioned blocks except one. An arbitrary n x n block partitioned direct coefficients matrix can be represented as a sum of n-squared almost null matrices. Properties of almost null matrices are exploited to enable analytically manageable expressions for the Leontief inverse to be written entirely in terms of the almost null matrices making up the direct coefficients matrix. Additive and multiplicative representations in terms of groupings of almost null matrices are provided.

Exertional sickling: Questions and controversy

Sickle cell trait (SCT) occurs in about 8% of African-Americans and is often described to be of little clinical consequence. Over time, a number of risks have emerged, and among these are rare but catastrophic episodes of sudden death in athletes and other individuals associated with physical activities which is often described as exercise collapse associated with sickle trait (ECAST). Despite an epidemiologic link between SCT and sudden death as well as numerous case reports in both medical literature and lay press, no clear understanding of the key pathophysiologic events has been identified. Strategies for identification of individuals at risk and prevention of ECAST have been both elusive and controversial. Stakeholders have advocated for different approaches to this issue particularly with regard to screening for hemoglobin S. Furthermore, the recommendations and guidelines that are in place for the early recognition of ECAST and the prevention and treatment of the illness are not well defined and remain fragmented. Among the cases identified, those in collegiate football players in the United States are often highlighted. This manuscript examines these case studies and the current recommendations to identify areas of consensus and controversy regarding recommendations for prevention, recognition and treatment of ECAST

Mechanical properties of a degradable phosphate glass fibre reinforced polymer composite for internal fracture fixation

NOTICE: this is the author’s version of a work that was accepted for publication in Materials Science and Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials Science and Engineering, [VOL 30, ISSUE 7, (2010)] DOI: 10.1016/j.msec.2010.04.017

Risk and Growth: Theoretical Relationships and Preliminary Estimates for South Africa

In the recent literature on economic growth there is disagreement over the relationship between growth and volatility and their relative benefits and costs in welfare terms. An analytical resolution of this issue, which has serious implications for domestic and international development policies, has been seen to be contingent upon how relative risk aversion and intertemporal substitutability are related in frameworks characterizing utility maximization of representative agents. It is commonly assumed that these aspects of preferences are rigidly linked, casting doubt on the expected utility maximizing paradigm as an appropriate modeling methodology for analyzing this important issue. In this paper it is first shown that these concerns are only relevant for special functional forms that enforce a unitary consumption elasticity of wealth. Next, a theoretical approach is employed to specify a more general relationship between risk aversion and intertemporal substitutability. The theoretical model is developed in the context of a two country representative agent model where risk affects domestic and direct foreign investment in both countries. The two country orientation is also capable of interpretation of the relationship between one country and the rest of the world. In a preliminary empirical application of the methodology to South African data, we attempt estimation of the parameters of generalized functions for preferences and technology which are capable of distinguishing between risk aversion and intertemporal substitutability.

Managing sacred sites for tourism: A case study of visitor facilities in Palmyra, New York

Sacred sites are qualitatively different than others developed for tourism purposes. However, sacred sites do have touristic appeal and can benefit from their popularity as both pilgrimage and secular tourist attractions. To protect the sacred resource and to make the touristic or culminating pilgrimage experience meaningful, many site managers develop well designed, well maintained and efficiently operated tourist facilities such as visitor centers, interpretive resources, and events. These facilities serve specifically to accommodate a wide range of site-based experiences from satisfaction of curiosity to life-changing hierophanies. Palmyra, New York is rich with cultural and religious sites that attract thousands of tourists each year. Most sites are meaningful to members of the Church of Jesus Christ of Latter-day Saints (LDS) who travel to Palmyra to see the birthplace of their religion. Later-day Saint sacred sites are important to the many pilgrim-like visitors and to the community in which they are located. The world-class tourist facilities and events associated with LDS sacred sites provide positive opportunities for social and economic development in the region. Specifically, this case study examines the positive impacts, which include site preservation and protection, education and interpretation, social identification, hospitality, social buffering, employment, local spending, tourism product enhancement, marketing, and business networking

Estimating components of ICT expenditure: a model-based approach with applicability to short time-series

This paper develops a microeconomic model-based approach to forecast national information and communications technology expenditure that is helpful when only very short time-series are available. The model specification incorporates parameters for network effects and national e-readiness. Finally, the model allows for observed non-homotheticity and ‘noise’ found in sample data, with the latter attributed to country-specific influences.ICT forecasts; short time-series; microeconomic modeling