Assessment of Self-Compacting Concrete Immersed in Acidic Solutions

Ettringite and thaumasite can be found among the deterioration products of cementitious materials exposed to sulfate and hydrochloric attack. The results of a test program to investigate the acid resistance of self-compacting concrete (SCC) and conventional concrete (CC), immersed up to 18 weeks at 20°C in sulfuric and hydrochloric acid solutions, are described. The SCC was prepared with 47% carboniferous limestone powder, as a replacement for cement, and an ordinary portland cement. The CC was prepared with portland cement only. The water-binder ratios of the SCC and CC were 0.36 and 0.46, respectively. The parameter investigated was the time, in weeks, taken to cause 10% mass loss of fully immersed concrete specimens in a 1% solution of sulfuric acid and the same amount of loss in a 1% solution of hydrochloric acid. The investigation indicated that the SCC performed better than the CC in sulfuric solution but was slightly more vulnerable to hydrochloric acid attack compared to CC. The mode of attack between the two solutions was different.

Polarimetric signatures of infrared jets in X-ray binaries

We present near-infrared linear spectropolarimetry of a sample of persistent X-ray binaries, Sco X-1, Cyg X-2 and GRS 1915+105. For Sco X-1 and Cyg X-2, the polarization levels at 2.4 µm are 1.3+/-0.10% and 5.4+/-0.7%, respectively, which is greater than the polarization level at 1.65 µm. This cannot be explained by interstellar polarization or electron scattering in the anisotropic environment of the accretion flow. We propose that the most likely explanation is that this is the polarimetric signature of synchrotron emission arising from close to the base of the jet. For Sco X-1 the position angle of the radio jet on the sky is approximately perpendicular to the near-infrared position angle (electric vector), suggesting that the magnetic field is aligned with the jet. These observations may be a first step towards probing the ordering, alignment, and variability of the outflow magnetic field, in a region closer to the central accreting object than is observed in the radio band.

P300 investigation of phoneme change detection in dyslexic adults

A specific impairment in phoneme awareness has been hypothesized as one of the current explanations for dyslexia. We examined attentional shifts towards phonological information as indexed by event-related potentials (ERPs) in normal readers and dyslexic adults. Participants performed a lexical decision task on spoken stimuli of which 80% started with a standard phoneme and 20% with a deviant phoneme. A P300 modulation was expected for deviants in control adults, indicating that the phonological change had been detected. A mild and right-lateralized P300 was observed for deviant stimuli in controls, but was absent in dyslexic adults. This result suggests that dyslexic adults fail to make shifts of attention to phonological cues in the same way that normal adult readers do. (C) 2003 Elsevier Ireland Ltd. All rights reserved.

Phonological oddballs in the focus of attention elicit a normal P3b in dyslexic adults

Difficulties in phonological processing have been proposed to be the core symptom of developmental dyslexia. Phoneme awareness tasks have been shown to both index and predict individual reading ability. In a previous experiment, we observed that dyslexic adults fail to display a P3a modulation for phonological deviants within an alliterated word stream when concentrating primarily on a lexical decision task [Fosker and Thierry, 2004, Neurosci. Lett. 357, 171-174]. Here we recorded the P3b oddball response elicited by initial phonemes within streams of alliterated words and pseudo-words when participants focussed directly on detecting the oddball phonemes. Despite significant verbal screening test differences between dyslexic adults and controls, the error rates, reactions times, and main components (P2, N2, P3a, and P3b) were indistinguishable across groups. The only difference between groups was found in the NI range, where dyslexic participants failed to show the modulations induced by phonological pairings (/b/-/p/ versus /r/ /g/) in controls. In light of previous P3a differences, these results suggest an important role for attention allocation in the manifestation of phonological deficits in developmental dyslexia. (c) 2005 Elsevier B.V. All rights reserved.

A Profile of Adolescent Cocaine Use in Northern Ireland.

Background: The image of cocaine as a 'party' drug used by more affluent members of society has begun to change as the levels of use of the drug rise amongst school aged young people. Methods: Cocaine use patterns amongst young people aged 13-16 years who were participating in the Belfast Youth Development Study, a longitudinal study of adolescent drug use was explored. Data was collected through an annual datasweep in participating schools. This paper includes data collected in years 3, 4 and 5 of the study. Results: The results show higher levels of cocaine use amongst this age group than reported in much of the existing harm reduction literature. Lifetime use was 3.8% at age 13-14 years, rising to 7.5% at 15-16 years. The profile indicated that adolescent cocaine users were more likely to be female, live in disrupted families and experience social deprivation which is similar to existing adolescent drug use profiles. There was also some evidence of experimental cocaine use amongst the sample. Conclusions: These findings provide further evidence for the development of age appropriate school focused harm reduction initiatives and continued monitoring of contemporary trends of use of cocaine amongst school aged young people.

Mercurous azide, Hg-2(N-3)(2)

White polycrystalline mercurous azide, Hg-2(N-3)(2), is obtained by combining aqueous solutions of NaN3 and Hg-2(NO3)(2).2H(2)O (made viscuous by addition of tetramethoxysilane and heating at 65 degreesC). The crystal structure was solved and refined from X-ray powder diffraction data (monoclinic, P2(1)/n, a = 596.07(2) pm, b = 1259.07(4) pm, c = 357.95(1) pm, beta 103.253(2)degrees, Z = 2, R-B = 0.0519). Solid Hg-2(N-3)(2) contains, essentially, molecules of that composition with Hg-Hg distances of 254.4(3) pm, Hg-N distances of 218(2) pm and Hg-Hg-N angles of 178.7(6)degrees. Weak intermolecular interactions with Hg-N distances starting at 280(3) pm lead to a three-dimensional structure.

Neurokinin A is the predominant tachykinin in human bronchoalveolar lavage fluid in normal and asthmatic subjects

BACKGROUND—Multiple sensory neuropeptides are present in human airways and may contribute to diseases such as asthma. This study quantified and characterised substance P (SP), neurokinin A (NKA), and calcitonin gene related peptide (CGRP) immunoreactivity in bronchoalveolar lavage fluid in asthmatic and normal subjects.
METHODS—Using specific radioimmunoassay (RIA), SP, NKA and CGRP were measured in bronchoalveolar lavage fluid from asthmatic subjects (n = 5), normal subjects (n = 5), atopic non-asthmatic subjects (n = 6), and asthmatic subjects four hours after allergen challenge (n = 12). Peptide immunoreactivity was characterised using high performance liquid chromatography (HPLC) and RIA.
RESULTS—No SP or CGRP immunoreactivity was detected in any of the fractions from samples after extraction, HPLC, and RIA. Non-specific binding resulted in spurious SP immunoreactivity being detected in bronchoalveolar lavage fluid when no extraction process was employed. NKA was detected in significant amounts in asthmatic (median 550, range 425-625 pg/ml) and normal subjects (median 725, range 350-1425 pg/ml). The level of NKA was significantly higher in the asthmatic subjects after allergen challenge (median 750, range 350-1250 pg/ml) than in unchallenged asthmatic subjects (median 600, range 425-600 pg/ml, p<0.01).
CONCLUSIONS—Extraction and characterisation of peptides from bronchoalveolar lavage fluid must be performed to ensure that the measured immunoreactivity represents target peptide. NKA is present in bronchoalveolar lavage fluid in high concentrations and is the predominant tachykinin. The concentrations of NKA are similar in normal subjects and subjects with mild asthma.

The effect of feeding a high fibre diet on the welfare of sows housed in large dynamic groups

This study assessed the effect of increasing fibre levels in the concentrate ration on the welfare of sows housed in a large dynamic group. One hundred and twelve Large White x Landrace sows were allocated to one of two treatments over six replicates. Treatments were as follows: (i) High Fibre diet (similar to 15% CF [Crude Fibre]), and (ii) Control diet (similar to 5% CF). Treatments were applied to two separate dynamic groups each containing 33 (+/- 3) sows in a cross-over design, after three replicates the treatments were switched between the groups. Approximately nine sows were replaced in each of these groups at 3-week intervals (each replacement constituting a replicate of the study). Sows on the high fibre diet spent a greater percentage of time lying (High Fibre: 43.8, Control. 28.0, SEM 3.25%), while sows on the control diet spent more time sham chewing (High Fibre: 7.2, Control: 28.8, SEM 1.55%). Sows newly introduced to the group on the high fibre treatment spent proportionally more time in the kennel areas compared to newly introduced sows in the control treatment (High Fibre. 0.893, Control. 0 788, SEM 5 10) In general, aggression occurred at a very low frequency and overall levels did not differ between treatments (High Fibre: 0.005, Control: 0.003, SEM 0.0007 [occurrences per min)). However, sows in the control treatment performed head thrusting (High Fibre: 0.02, Control: 0.00, SEM 0.001 [occurrences per mini), and biting behaviour (High Fibre. 002, Control. 0.01, SEM 0.002 [occurrences per min]) more frequently than sows on the high fibre diet. There was no effect of treatment on physiological parameters such as plasma cortisol (High Fibre: 1.34, Control: 1.44, SEM 0.114 ng ml(-1)) or haptoglobin levels (High Fibre. 0.73, Control. 0.64, SEM 0.080 mg ml(-1)). In summary, provision of a high fibre diet had a positive effect on the welfare of group-housed dry sows Sows on the high fibre treatment spent more time resting in the kennel areas, less time performing stereotypic behaviours and showed a reduction in some aggressive behaviours relative to sows fed the control diet.

Families with multiple problems: Some challenges in identifying and providing services to those experiencing adversities across the life course

Summary A concern amongst policy makers to identify high cost and low productivity populations has created a new interest in identifying those who experience adversities across the life-course. This paper outlines the development of conceptual understandings of families whose children experience multiple adversities and links this with later poor outcomes in adult life and examines some of the research challenges in establishing such linkages. Findings It is argued that current thinking with regard to these issues reflects historical domains within which services to children and to adults are located. The challenge to domain thinking is both horizontal and vertical. Policy being required to address the horizontal axis by co-ordinating planned approaches to multiple needs across services. And policy being necessary to address the vertical cleavage between children’s and adult services in ways which join up services across the life path; conceptually and practically acknowledging the links between child and adult experiences. Application Such policy developments will inevitably require social work to develop alternative paradigms for understanding the needs of children and adults and designing services to effectively meet these.

Finite element analysis of an embankment on a soft estuarine deposit using an elastic–viscoplastic soil model

A new elastic–viscoplastic (EVP) soil model has been used to simulate the measured deformation response of a soft estuarine soil loaded by a stage-constructed embankment. The simulation incorporates prefabricated vertical drains installed in the foundation soils and reinforcement installed at the base of the embankment. The numerical simulations closely matched the temporal changes in surface settlement beneath the centerline and shoulder of the embankment. More importantly, the elastic–viscoplastic model simulated the pattern and magnitudes of the lateral deformations beneath the toe of the embankment — a notoriously difficult aspect of modelling the deformation response of soft soils. Simulation of the excess pore-water pressure proved more difficult because of the heterogeneous nature of the estuarine deposit. Excess pore-water pressures were, however, mapped reasonably well at three of the six monitoring locations. The simulations were achieved using a small set of material constants that can easily be obtained from standard laboratory tests. This study validates the use of the EVP model for problems involving soft soil deposits beneath loading from a geotechnical structure.