Specification and estimation of spatial econometric models : A discussion of alternative strategies for spatial economic modelling

The semantical insufficiency of (spatial) economic theories necessitates the making of additional assumptions — thereby introducing substantial specification uncertainty — in order to arrive at a fully specified econometric model. The traditional or current approach to econometric modelling treats specification uncertainty inadequately. This proposition is illustrated by two well-known examples from the spatial economic literature. Two alternative specification strategies for spatial economic modelling — designed to improve the current spatial econometric modelling approach — are proposed. One of these strategies is used for a specification analysis of agricultural output in Eire

Inversionistas institucionales, reforma del régimen de pensiones y mercados bursátiles emergentes

(Disponible en idioma inglés únicamente) En este trabajo se trata la gama de factores que pueden estimular un mayor desarrollo del sector institucional interno mediante medidas de reforma de los sistemas de pensiones. El desarrollo del sector institucional de las economías de mercados emergentes se compara con las experiencias de los países miembros de la OCDE. La atención se concentra en los factores claves que han venido (y siguen) impulsando el crecimiento de las actividades de los inversionistas institucionales de la OCDE y el efecto de los inversionistas institucionales en los mercados bursátiles.

Testing the spatial scale and the dynamic structure in regional models (a contribution to spatial econometric specification analysis)

This article addresses the problem of specification uncertainty in modeling spatial economic theories in stochastic form. It is ascertained that the traditional approach to spatial econometric modeling does not adequately deal with the type and extent of specification uncertainty commonly encountered in spatial economic analyses. Two alternative spatial econometric modeling procedures proposed in the literature are reviewed and shown to be suitable for analyzing systematically two sources of specification uncertainty, viz., the level of aggregation and the spatio-temporal dynamic structure in multiregional econometric models. The usefulness of one of these specification procedures is illustrated by the construction of a simple multiregional model for The Netherlands

Recursive algorithms for the elimination of redundant paths in spatial lag operators

Recursive algorithms for the elimination of redundant paths in spatial lag operators are introduced. It is shown that these algorithms have superior computational properties in comparison with the cumbersome procedure proposed by Ross and Harary (1952). A rigorous definition of spatial lag operators is given, while a number of mathematical results and properties are derived. Theoretical and empirical results regarding the performance of the proposed algorithms are presented

Monetary Policy Rules, Adverse Selection and Long-Run Financial Risk

This paper constructs a macro-finance model with two types of borrowers: entrepreneurs who engage in productive activities and gamblers who play in lotteries. It links a central bank's interest rate policy to expected cash ows of both types of borrowers. Via this link we study how the interactions between various shocks and different monetary policy rules affect the quality of the borrower pool faced by financial intermediaries. We find that if the economy is hit by an expansionary monetary policy shock, in the long run the proportion of entrepreneurs in the borrower pool will be persistently lower than the steady state level. This worsening of the borrower pool is more serious if the central bank does not react to output uctuations. By contrast, not reacting to output uctuations in case of a negative productivity shock avoids a persistent worsening of the borrower pool in the long run.Monetary Policy;Adverse Selection;Financial Crisis

Reliability of measuring thoracic kyphosis angle, lumbar lordosis angle and straight leg raise with an inclinometer

Licensed under the terms of the Creative Commons Attribution non-commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, providing that the work is properly citedPurpose: Several non-invasive measurement methods have been described in the literature for recording thoracic kyphosis, lumbar lordosis and straight leg raise (SLR). However, attempts to quantify the reliability of the inclinometer in these measurements are scarce. In addition, existing reliability studies within the literature were found to use small sample sizes. The aim of this investigation was to examine the intra-rater reliability of the chief investigator (SM), in order to provide clinicians with data that will allow them to better measure sagittal spinal posture and SLR. A blinded test-retest design was performed to determine the intra-rater reliability of thoracic kyphosis, lumbar lordosis and SLR when assessed using an Isomed inclinometer in normals. Methods. Thirty asymptomatic subjects were assessed on two occasions separated by a time interval of 1 hour to reduce investigator memory bias. Thoracic and lumbar measurements were recorded in a relaxed standing position using an inclinometer; SLR of the dominant leg was assessed with subjects in the supine position. Intraclass correlation coefficients (ICC), 95% confidence intervals (CI), and standard errors of measurement (SEM) were analysed to determine measurement reliability. Results. The chief investigator demonstrated excellent intra-rater reliability in the measurements of thoracic kyphosis, lumbar lordosis and SLR. ICC (2,3) values for all three variables exceeded the 0.90 threshold suggesting that the reliability of these measures are acceptable for clinical application. Conclusions. The inclinometer technique employed in this study to record thoracic kyphosis, lumbar lordosis and SLR is a reliable measurement method.Peer reviewe

Power-Assist Wheelchair Attachment

This senior design project sought to combine the best characteristics of manual and power wheelchairs by creating a battery-powered attachment to propel a manual wheelchair. The primary customer needs were determined to be affordability, portability, and travel on uneven surfaces. After the initial prototype, using a hub motor proved unsuccessful, so a second design was developed that consisted of a gear reduction motor and drive wheel connected to the back of the wheelchair by a trailing arm that could be easily attached/detached from the frame. The prototype of the second design succeeded in meeting most of the project goals related to cost, off-road capability, inclines, and range. Improvements can be made by reducing the attachment weight and improving user control of the device