Potentially toxic metals in historic landfill sites: Implications for grazing animals

Municipal waste disposal is an increasing global problem, frequently solved by the use of landfill sites. Following closure, such sites contain a legacy of pollutants and must be managed to provide a safe and useful end life. The soils and vegetation from four historic landfill sites were analysed to determine the extent of pollution by potentially toxic metals (PTMs). Data were subsequently assessed to determine if post closure uses involving grazing were safe for the animals. The heaviest and widest spread soil contamination was due to Ni. Concentrations at all sites exceeded the 95th percentile value for rural soils, in one case by a factor of 30. Cu and Pb contamination was identified at some sites, but no evidence of Al or Zn contamination was found. Oral bioaccessibility testing showed that the availability of Ni in soil was exceedingly low, whilst that of Cu and Pb was high. Concentrations in plant shoots differed significantly amongst the sites, but interspecific differences in shoot concentration were only significant in the case of Cu. The results indicated that exposure levels to grazers would be at or below tolerable levels, indicating that it is generally safe to graze historic landfill. However, animals could be exposed to higher levels of PTMs than would be expected from rural locations, and grazing under conditions where soil consumption may be high could result in levels of exposure to Al, Ni and Pb exceeding tolerable levels. © Springer International Publishing 2014

Determination of sin2 θeff w using jet charge measurements in hadronic Z decays

The electroweak mixing angle is determined with high precision from measurements of the mean difference between forward and backward hemisphere charges in hadronic decays of the Z. A data sample of 2.5 million hadronic Z decays recorded over the period 1990 to 1994 in the ALEPH detector at LEP is used. The mean charge separation between event hemispheres containing the original quark and antiquark is measured for bb̄ and cc̄ events in subsamples selected by their long lifetimes or using fast D*'s. The corresponding average charge separation for light quarks is measured in an inclusive sample from the anticorrelation between charges of opposite hemispheres and agrees with predictions of hadronisation models with a precision of 2%. It is shown that differences between light quark charge separations and the measured average can be determined using hadronisation models, with systematic uncertainties constrained by measurements of inclusive production of kaons, protons and A's. The separations are used to measure the electroweak mixing angle precisely as sin2 θeff w = 0.2322 ± 0.0008(exp. stat.) ±0.0007(exp. syst.) ± 0.0008(sep.). The first two errors are due to purely experimental sources whereas the third stems from uncertainties in the quark charge separations

Understanding suicidal ideation in psychosis: findings from the Psychological Prevention of Relapse in Psychosis (PRP) Trial

Objective: To examine the clinically important phenomenon of suicidal ideation in psychosis in relation to affective processes and the multidimensional nature of hallucinations and delusions.Method: In a cross-sectional study of 290 individuals with psychosis, the associations between level of suicidal ideation, affective processes, positive symptoms, clinical and demographic variables were examined.Results: Forty-one per cent of participants expressed current suicidal ideation. Suicidal ideation was associated with depressed mood, anxiety, low self-esteem, negative illness perceptions, negative evaluative beliefs about the self and others and daily alcohol consumption. Frequency of auditory hallucinations and preoccupation with delusions were not associated with suicidal ideation; however, positive symptom distress did relate to suicidal thoughts.Conclusion: Affective dysfunction, including distress in response to hallucinations and delusions, was a key factor associated with suicidal ideation in individuals with psychotic relapse. Suicidal ideation in psychosis appears to be an understandable, mood-driven process, rather than being of irrational or 'psychotic' origin