The effect of vibratory stress on the welding microstructure and residual stress distribution

Previous studies have suggested that weld microstructure may be modified by the presence of static stresses. In this investigation, vibratory stress was applied to mild steel specimens while they were being welded to observe its effect on the residual stress, microstructure and hardness of the material. Residual stresses were found to decrease in response to vibration whether it was applied during welding or after welding. It was found that the applied stress influenced the grain growth process in the weld. As a result of the treatment the hardness of the material was found to be increased by 25 per cent

Drug Points: Apparent interaction between warfarin and levonorgestrel used for emergency contraception

No abstract available

A theoretical model of a new electrostatic transducer incorporating fluidic amplification

This article concerns the design of a new electrostatic transducer whose backplate consists of a series of drilled pipes. A new one-dimensional model is derived which considers the interaction of the membrane with the air load, the air cavities, and the drilled pipes in the backplate. Dynamic equations for the impedance in each component of the device are calculated analytically and connected using interface conditions of continuity of pressure and radiation conditions into the air load. The model is able to produce solutions to the mechanical impedance of the device and the displacement of the membrane as a function of the device's design parameters. Model results for the output pressure compare well with previous experimental data. The inverse problem of retrieving the design parameters for a desired output is discussed

Inorganic elements in the livers of Eurasian otters, Lutra lutra, from England and Wales in 2007 & 2008: a Predatory Bird Monitoring Scheme (PBMS) report

This is a report on the initial findings of a collaborative study between the Predatory Bird Monitoring Scheme (PBMS) and the Cardiff University Otter Project (CUOP). The study analysed the concentrations of 16 metals and semi-metals in the livers of 107 Eurasian otters (Lutra lutra) that had been found dead in 2007 and 2008 and collected by the CUOP. This aim of this work was to determine the current concentrations of inorganic elements accumulated by otters and whether exposure to heavy metals (lead, mercury, cadmium) in particular is likely to be associated with adverse effects. This is the first study of inorganic elements in otter livers from Europe for nearly 10 years. The otters that were analysed were from England and Wales and included adult and subadult males and females. Liver tissue was analysed using Inductively Coupled Plasma mass spectrometry (ICP-MS) techniques. The concentrations of inorganic elements measured in the present study were within the range previously reported for Eurasian otters in Britain and elsewhere in Europe. Concentrations varied with age and/or sex for some elements. For the heavy metals mercury and cadmium, liver concentrations generally increased with age whereas for lead, juveniles generally had higher liver lead concentrations than adults although for lead these difference were not statistically significant. Aluminium and chromium were the only elements that varied significantly in concentrations between years. It is unclear whether the inter-year variation in aluminium and chromium represent significant inter-year changes in exposure and/or accumulation or may simply reflect local-scale variation in the provenance of otters and their associated exposure. The liver concentrations of heavy metals (mercury, cadmium and lead) in all the otters analysed were below those associated with toxic effects in mammals, although liver lead concentrations in a small number of otters were close to the level of concern

Persistent Organic Pollutants (POPs) and inorganic elements in predatory bird livers and eggs 2007 to 2009: a Predatory Bird Monitoring Scheme (PBMS) Report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Sparrowhawk livers were analysed for a range of persistent organic pollutants (POPs) and heavy metals. Sparrowhawks are studied because they have a wide distribution across the Britain and can be used as a sentinel species for the terrestrial environment. Mean PCB and mercury liver concentrations were below those thought to have an adverse effect on individual birds. Pollutants, such as mercury and PCBs, can affect development and hatchability. Therefore, the PBMS also monitors the levels of contaminants in the eggs of a range of species including those of conservation concern, such as golden eagle and the re-introduced white-tailed sea eagle. Other species that are monitored are the northern gannet, which is used as a monitor of the marine environment, and merlin that hunts in upland habitats. The residues measured in the eggs of golden eagle and gannets collected between 2007 and 2009 were below those thought to have an adverse effect, but some residues in individual merlin eggs were above concentrations suggested to be indicative of no effect concentrations for birds generally. Few white-tailed see eagle eggs are received for analysis by the PBMS but many of the eggs that have been analysed, including one of the eggs analysed for this report, have DDE, PCB and/or mercury concentrations above levels associated with adverse effects on bird embryos and hatching success. In terms of long-term trends, there has been a decline in congener sum PCB contamination in the eggs of most of the species that have been monitored, except for coastal nesting golden eagles. In contrast however, there has been no significant decline over time in PCB concentrations in sparrowhawk livers and concentrations of ‘Paris 10’ congener sum and PCB-TEQ concentrations have also largely remained unchanged in both livers and eggs since monitoring began in 1996. Evidence for changes over time in mercury concentrations in predatory birds or their eggs is inconsistent across the species monitored. Where a decline has been detected, it has occurred before approximately 1990 and remained largely unchanged since then

Lead (Pb) concentrations in predatory bird livers 2010 and 2011: a Predatory Bird Monitoring Scheme (PBMS) report

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife. Lead (Pb) is a highly toxic metal that acts as a non-specific poison affecting all body systems and has no known biological requirement. Sources of Pb in the environment include lead mining, the refining and smelting of lead and other metals, the manufacture and use of alkyl lead fuel additives, and the use of lead ammunition. The present study is the first two years of a PBMS monitoring programme to quantify the scale of exposure to [and associated risk from] Pb in predatory birds. The aim is to quantify the extent of exposure to lead [as assessed from liver residues] in two predatory bird species, the red kite (Mivus milvus) and the sparrowhawk (Accipiter nisus). The red kite is a scavenger and, as such, is particularly at risk from consumption of Pb ammunition in unretrieved game. Sparrowhawks prey predominantly upon live passerine birds that are unlikely to be shot in the UK; likely sources of exposure are diffuse Pb contamination although some individuals may also be exposed to Pb particles ingested by their prey. We also examined the liver Pb isotope ratios in to explore whether they can be used to ascribe likely sources of any Pb detected in the birds. Red kites had significantly higher Pb concentration than those measured in sparrowhawks but the majority of sparrowhawks and all the red kites had liver Pb concentrations below those thought to cause clinical and sub-clinical adverse effects in Falconiforme species. There was overlap in the liver Pb isotope ratios of red kites and sparrowhawks yet there was evidence of separation between the two species. There was also evidence of overlap with the isotope signature for coal and for Pb shot but the isotope signatures in the bird livers were distinct from that of petrol Pb. The Pb isotope pattern observed in the red kites and sparrowhawks in the current study may reflect the fact that liver Pb concentrations were low in the small sample of birds that were analysed and may have been a result of exposure to low-level, diffuse contamination.birds. Red kites had significantly higher Pb concentration than those measured in sparrowhawks but the majority of sparrowhawks and all the red kites had liver Pb concentrations below those thought to cause clinical and sub-clinical adverse effects in Falconiforme species. There was overlap in the liver Pb isotope ratios of red kites and sparrowhawks yet there was evidence of separation between the two species. There was also evidence of overlap with the isotope signature for coal and for Pb shot but the isotope signatures in the bird livers were distinct from that of petrol Pb. The Pb isotope pattern observed in the red kites and sparrowhawks in the current study may reflect the fact that liver Pb concentrations were low in the small sample of birds that were analysed and may have been a result of exposure to low-level, diffuse contamination

The influence of vibratory treatment on the fatigue life of welds : a comparison with thermal stress relief

A comparison has been made between the fatigue lives of welded specimens a) in the as welded condition b) after heat treatment, and c) after post-weld vibration. By comparison with the aswelded specimens, the fatigue lives of the thermally relieved specimens were found to decrease by 43%, while the vibration treated specimens showed an increase of between 17% and 30%. While these findings are interesting in that they offer a way of extending the fatigue lives of welded joints, they confirm the view that the mechanism of residual stress relieving in the vibratory stress relief (VSR) method, and its relationship with fatigue life is poorly understood

The Predatory Bird Monitoring Scheme (PBMS) Report 2006-7

The Predatory Bird Monitoring Scheme (PBMS) examines the levels of certain pollutants in selected wildlife species in Britain. It started in the 1960s to assess the impact of organochlorine pesticides on raptor populations, and the scheme is now the longest-running of its kind in the world. The aims of the PBMS are to monitor the levels of contaminants to determine how and why they vary between species and regions, how they are changing over time, and the risks they may have on individual birds and on their populations. Dead predatory birds are submitted to the PBMS by the public and by wildlife hospitals, veterinarian and zoological organisations. Eggs are collected, under licence, from a range of nests. The majority of these eggs are addled or deserted, although for some species, e.g. northern gannets, fresh egg are sampled. Second generation anticoagulant rodenticides (SGARs) are potentially toxic to all mammals and birds, and predators that feed upon rodents are particularly likely to be exposed to these compounds. Since 1983 the PBMS has monitored SGAR residues in barn owls, while kestrels have been monitored since 2001. The proportion of barn owls which have one or more SGARs in their liver increased from less than 10% in the 1980s to approximately 40% in the early 2000s. However, there has been a small decrease in this percentage in the last few years. A higher proportion of kestrels have detectable residues of SGARs in their liver than barn owls with 60% of birds received in the years 2001 to 2006 having one or more SGAR in their liver. There is no evidence of a change over time in the proportion ok kestrels with detectable liver SGAR residues. Overall, the high incidence of exposure amongst monitored species remains of concern. Sparrowhawk livers are analysed for a range of persistent organic pollutants (POPs) and heavy metals. Sparrowhawks are studied because they have a wide distribution across the Britain and can be used as a sentinel species for the terrestrial environment. Following restrictions on its use as an agricultural pesticide, mercury concentrations have declined in sparrowhawks. However, despite PCBs being banned in 1981, there has not been any long-term change in polychlorinated biphenyl (PCB) liver concentrations in sparrowhawks during the period 1968-2006. In herons, used as a sentinel species for freshwater habitats, both PCB and mercury concentrations have declined. In 2006, mean PCB and mercury concentrations in both species were below those thought to have an adverse effect on individual birds. Pollutants, such as mercury and PCBs, can affect development and hatchability.. Therefore, the PBMS monitors the levels of contaminants in the eggs of a range of species including those of conservation concern such as golden eagle and the re-introduced white-tailed sea eagle. Other species that are monitored are the northern gannet, which are used as a monitor of the marine environment, and merlin that hunt in upland habitats. In general, and specifically in 2006, the residues measured in the eggs of golden eagle and gannets are below those thought to have an adverse effect on bird eggs, but some residues in individual merlin eggs were at concentrations associated with effects in other species. Few white-tailed see eagle eggs are received for analysis by the PBMS but a large proportion of those eggs that have been analysed, including the egg collected in 2006, have DDE, PCB and mercury concentrations above levels associated with adverse effects on bird embryos and the hatching success of eggs. Despite the withdrawal of PCBs from manufacturing over 20 years ago, the evidence for declining PCB concentrations in predatory birds is equivocal, with declines in liver or egg residues in some species but not in others. Mercury concentrations in most species have not significantly changed during the monitoring period

Immunology knowledge as one of the basic sciences that forms the foundations to developing sound clinicians

Objective: The aim of this study was to (1) generate a valid questionnaire to determine immunology knowledge, (2) compare immunology knowledge across 3 different cohorts of chiropractic students that had already studied immunology, (3) examine the attitudes of chiropractic students to the study of immunology, and (4) examine whether students' attitudes affected their knowledge levels. Methods: Factor analysis was used to refine an immunology knowledge and perceptions questionnaire that was generated by a group of experts that was then completed by 90 students. Immunology knowledge level of each of the cohorts was compared using a 1-way analysis of variance. Kappa statistics were used to measure agreement between 2 statements, and logistic regression was used to determine whether students' attitudes were associated with their knowledge levels. Results: There was a significant difference in the immunology knowledge levels across the 3 year groups (F[2, 87] = 4.78, p = .011). Fifth-year students (n = 26) demonstrated 25% less immunology knowledge than third-year students (n = 35; p = .005). Of 90 students, 64 agreed that immunology knowledge was important to chiropractors, and 53 agreed that immunology knowledge was important for the average person. No relationship existed between their value of immunology knowledge and their score on the multiple-choice questions. Conclusion: Third-year students' immunology knowledge was significantly higher than that of the fifth-year students. Students value immunology knowledge, but this does not translate to retention of this knowledge. The validated questionnaire is a useful tool for assessing immunology knowledge retention for undergraduate students