Determinants of trade union membership in Great Britain during 1991-2003

We analyse the determinants of union membership in the UK using data from the BHPS (1991-2003). Employing three alternative methodologies to control for the problem of initial conditions we find that union membership remains persistent even after controlling for the unobserved effect. There is evidence of a considerable correlation between the unobserved individual heterogeneity and the initial membership status. Ignoring this overstates the degree of state dependence of union membership greatly. The extent of state dependence in union membership status is notably higher in the (1991-1996) period estimates and appears to be more pronounced in the case of male employees for the entire period under analysis. The second period estimates reveal that unobserved heterogeneity has a more prominent impact in determining future unionisation probability versus past union membership. Finally, the estimates suggest that an individual´s propensity to unionise is determined by a mixture of industrial and personal characteristics. This is at odds with earlier studies, such as Booth (1986) and Wright (1995), failing to control for unobservable effects and concluding that personal attributes do not have a significant impact on unionisation propensity

Estimating union wage effects in Great Britain during 1991-2003

Using a dynamic model of unionism and wage determination we find that the unobserved factors that influence union membership also affect wages. The estimates suggest that UK trade unions still play a non-negligible, albeit diminishing, role in wage formation. It appears that the greater impact of un observables in determining individual union propensity concerning the second period under analysis, versus past unionisation experience, implies that those remaining in unions during (1997-2002) gain most from their sorting decision. The significant contribution of unobserved heterogeneity renders the total union wage differential highly variable across individuals. The endogeneity correction procedure employed yields a discernible pattern of the estimated union wage effect relative to OLS and Fixed effects. This is in line with Robinson (1989a) and Vella and Verbeek (1998) and refutes the pessimistic conclusions reached by Freeman and Medoff (1982) and Lewis (1986) that endogeneity correction methodologies do not contribute to our understanding of the union wage effect puzzle

Estimating union wage effects in Great Britain during 1991-2003

Using a dynamic model of unionism and wage determination we find that the unobserved factors that influence union membership also affect wages. The estimates suggest that UK trade unions still play a non-negligible, albeit diminishing, role in wage formation. It appears that the greater impact of un observables in determining individual union propensity concerning the second period under analysis, versus past unionisation experience, implies that those remaining in unions during (1997-2002) gain most from their sorting decision. The significant contribution of unobserved heterogeneity renders the total union wage differential highly variable across individuals. The endogeneity correction procedure employed yields a discernible pattern of the estimated union wage effect relative to OLS and Fixed effects. This is in line with Robinson (1989a) and Vella and Verbeek (1998) and refutes the pessimistic conclusions reached by Freeman and Medoff (1982) and Lewis (1986) that endogeneity correction methodologies do not contribute to our understanding of the union wage effect puzzle.Union status, Union wage effects, Unobserved heterogeneity, Dynamic model of unionism and wage determination

Determinants of trade union membership in Great Britain during 1991-2003

We analyse the determinants of union membership in the UK using data from the BHPS (1991-2003). Employing three alternative methodologies to control for the problem of initial conditions we find that union membership remains persistent even after controlling for the unobserved effect. There is evidence of a considerable correlation between the unobserved individual heterogeneity and the initial membership status. Ignoring this overstates the degree of state dependence of union membership greatly. The extent of state dependence in union membership status is notably higher in the (1991-1996) period estimates and appears to be more pronounced in the case of male employees for the entire period under analysis. The second period estimates reveal that unobserved heterogeneity has a more prominent impact in determining future unionisation probability versus past union membership. Finally, the estimates suggest that an individual´s propensity to unionise is determined by a mixture of industrial and personal characteristics. This is at odds with earlier studies, such as Booth (1986) and Wright (1995), failing to control for unobservable effects and concluding that personal attributes do not have a significant impact on unionisation propensity.Union membership, Initial conditions, Unobserved individual heterogeneity, State dependence, Dynamic random effects probit models

A two-stage approach of manufacturing FeAl40 iron aluminides by self-propagating synthesis and pressureless sintering

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Powder Metallurgy on 11 June 2018, available online at https://doi.org/10.1080/00325899.2018.1478778. Under embargo until 11 June 2019.A two-stage sintering process was successfully used to sinter FeAl to densification levels of just above 95% at a temperature of 1300 ºC. In the first stage, mixed iron and aluminium powders were synthesised at 750°C via Self-Propagating High-temperature Synthesis (SHS) to form brittle and porous Fe2Al5. Then the pellets were crushed and milled to various sizes and mixed with iron powders in the nominal composition of FeAl40 and pressurelessly sintered at a higher temperature to obtain a higher densification by taking advantage of the less violent exothermic reaction of Fe2Al5 and Fe. The intermediate and end products in SHS and sintering were characterised by SEM/EDX and XRD. The porosity level of the final FeAl40 product was controlled by the heating rate and powder size, which was also strongly influenced by the temperature, holding time and the ratio of the two powders.Peer reviewedFinal Accepted Versio

Estimating union wage effects and the probability of union membership in the U.K. during 1991-2003

Using a dynamic model of unionism and wage determination we find that the unobserved factors that influence union membership also affect wages. We observe a significant decline in trade union membership persistence during the period under analysis. We find that UK trade unions still play a nonnegligible, albeit diminishing, role in wage formation. While unions were unable to establish a wage premium for male members during the two periods considered, the female union wage effect stood at (19.4%, 17.6%) during (1991-1996, 1997-2002) respectively. The endogeneity correction procedure employed yields a discernible pattern of the union wage effect relative to OLS and fixed effects thus, refuting the pessimistic conclusions reached by Freeman and Medoff (1982) and Lewis (1986) that endogeneity correction methodologies do not contribute to our understanding of the union wage effect puzzle.Union membership persistence, Union wage effects, Unobserved heterogeneity, Dynamic model of unionism and wage determination

Estimating Union Wage Effects in Great Britain During 1991-2003

Using a dynamic model of unionism and wage determination we find that the unobserved factors that influence union membership also affect wages. The estimates suggest that UK trade unions still play a non-negligible, albeit diminishing, role in wage formation. It appears that the greater impact of unobservables in determining individual union propensity concerning the second period under analysis, versus past unionisation experience, implies that those remaining in unions during (1997-2002) gain most from their sorting decision. The significant contribution of unobserved heterogeneity renders the total union wage differential highly variable across individuals. The endogeneity correction procedure employed yields a discernible pattern of the estimated union wage effect relative to OLS and Fixed effects. This is in line with Robinson (1989a) and Vella and Verbeek (1998) and refutes the pessimistic conclusions reached by Freeman and Medoff (1982) and Lewis (1986) that endogeneity correction methodologies do not contribute to our understanding of the union wage effect puzzle.union status, union wage effects, unobserved heterogeneity, dynamic model of unionism and wage determination

Determinants of Trade Union Membership in Great Britain During 1991-2003

The determinants of union membership in the UK are analysed using the BHPS(1991-2003). The paper employs three alternative methodologies to control for the problem of initial conditions. Trade union membership is found to be persistent even after controlling for the unobserved effect. There is evidence of a considerable correlation between the unobserved individual heterogeneity and the initial condition. Ignoring this overstates the degree of state dependence of union membership greatly. The extent of state dependence in union membership status is notably higher in the (1991-1996) period estimates and appears to be more pronounced in the case of male employees for the entire period under consideration. Concerning the observed heterogeneity the estimates suggest that an individual's propensity to unionise is determined by a mixture of industrial and personal characteristics that have a differential impact on male and female propensities.Union membership, initial conditions, unobserved individual heterogeneity, state dependence, dynamic random effects probit models

Formation of some transition metal carbides

Imperial Users onl

Agent Behaviour Simulator (ABS):a platform for urban behaviour development

Computer Graphics have become important for many applicationsand the quality of the produced images have greatly improved. Oneof the interesting remaining problems is the representation of densedynamic environments such as populated cities. Although recentlywe saw some successfulwork on the rendering such environments,the real?time simulation of virtual cities populated by thousands ofintelligent animated agents is still very challenging.In this paperwe describe a platformthat aims to accelerate the developmentof agent behaviours. The platform makes it easy to enterlocal rules and callbacks which govern the individual behaviours.It automatically performs the routine tasks such as collision detectionallowing the user to concentrate on defining the more involvedtasks. The platform is based on a 2D-grid with a four-layered structure.The two first layers are used to compute the collision detectionagainst the environment and other agents and the last two are usedfor more complex behaviours.A set of visualisation tools is incorporated that allows the testingof the real?time simulation. The choices made for the visualisationallow the user to better understand the way agents move inside theworld and how they take decisions, so that the user can evaluate ifit simulates the expected behaviour.Experimentation with the system has shown that behaviours inenvironments with thousands of agents can be developed and visualisedin effortlessly