Political Violence and Child Adjustment: Longitudinal Tests of Sectarian Antisocial Behavior, Family Conflict, and Insecurity as Explanatory Pathways

Understanding the impact of political violence on child maladjustment is a matter of international concern. Recent research has advanced a social ecological explanation for relations between political violence and child adjustment. However, conclusions are qualified by the lack of longitudinal tests. Toward examining pathways longitudinally, mothers and their adolescents (M = 12.33, SD = 1.78, at Time 1) from 2-parent families in Catholic and Protestant working class neighborhoods in Belfast, Northern Ireland, completed measures assessing multiple levels of a social ecological model. Utilizing autoregressive controls, a 3-wave longitudinal model test (T1, n = 299; T2, n = 248; T3, n = 197) supported a specific pathway linking sectarian community violence, family conflict, childrens insecurity about family relationships, and adjustment problems.

Short-pulse, extreme-ultraviolet continuum emission from a table-top laser plasma light source

We have observed extreme-ultraviolet (XUV) ''line-free'' continuum emission from laser plasmas of high atomic number elements using targets irradiated with 248 nm laser pulses of 7 ps duration at a power density of similar to 10(13) W/cm(2). Using both dispersive spectroscopy and streak camera detection, the spectral and temporal evolution of XUV continuum emission for several target atomic numbers has been measured on a time scale with an upper limit of several hundred picoseconds limited by amplified spontaneous emission. (C) 1997 American Institute of Physics.

Study of fibre distribution and orientations in UHPFRC by electrical resistivity and mechanical tests

This paper presents experimental tests carried out on steel fibre reinforced concrete samples, including mechanical tests as well as non-destructive technique (electrical resistivity) and non destructive technique on cores (X-ray). Electrical resistivity measurements are done as a blind test, to characterise the electrical anisotropy and deduce the distribution and the orientation of fibres. These results are compared to X-ray imaging to check the quality of the non destructive evaluation. Then, flexural and compressive strength are measured on specimens to assess the influence of fibre distribution on the concrete properties.

Use of recycled demolition aggregate in precast products, phase II: Concrete paving blocks

A study undertaken at the University of Liverpool has investigated the potential for using construction and demolition waste (C&DW) as aggregate in the manufacture of a range of precast concrete products, i.e. building and paving blocks and pavement flags. Phase II, which is reported here, investigated concrete paving blocks. Recycled demolition aggregate can be used to replace newly quarried limestone aggregate, usually used in coarse (6 mm) and fine (4 mm-to-dust) gradings. The first objective, as was the case with concrete building blocks, was to replicate the process used by industry in fabricating concrete paving blocks in the laboratory. The compaction technique used involved vibration and pressure at the same time, i.e. a vibro-compaction technique. An electric hammer used previously for building blocks was not sufficient for adequate compaction of paving blocks. Adequate compaction could only be achieved by using the electric hammer while the specimens were on a vibrating table. The experimental work involved two main series of tests, i.e. paving blocks made with concrete- and masonry-derived aggregate. Variables that were investigated were level of replacement of (a) coarse aggregate only, (b) fine aggregate only, and (c) both coarse and fine aggregate. Investigation of mechanical properties, i.e. compressive and tensile splitting strength, of paving blocks made with recycled demolition aggregate determined levels of replacement which produced similar mechanical properties to paving blocks made with newly quarried aggregates. This had to be achieved without an increase in the cement content. The results from this research programme indicate that recycled demolition aggregate can be used for this new higher value market and therefore may encourage demolition contractors to develop crushing and screening facilities for this. (C) 2011 Published by Elsevier Ltd.