Absolute dimensions of solar-type eclipsing binaries. EF Aquarii: a G0 test for stellar evolution models

Recent studies have shown that stellar chromospheric activity, and its effect on convective energy transport in the envelope, is most likely the cause of significant radius and temperature discrepancies between theoretical evolution models and observations. We aim to determine absolute dimensions and abundances for the solar-type detached eclipsing binary EF Aqr, and to perform a detailed comparison with results from recent stellar evolutionary models. uvby-beta standard photometry was obtained with the Stromgren Automatic Telescope. The broadening function formalism was applied on spectra observed with HERMES at the Mercator telescope in La Palma, to obtain radial velocity curves. Masses and radii with a precision of 0.6% and 1.0% respectively have been established for both components of EF Aqr. The active 0.956 M_sol secondary shows star spots and strong Ca II H and K emission lines. The 1.224 M_sol primary shows signs of activity as well, but at a lower level. An [Fe/H] abundance of 0.00+-0.10 is derived with similar abundances for Si, Ca, Sc, Ti, V, Cr, Co, and Ni. Solar calibrated evolutionary models such as Yonsei-Yale, Victoria-Regina and BaSTI isochrones and evolutionary tracks are unable to reproduce EF Aqr, especially for the secondary, which is 9% larger and 400 K cooler than predicted. Models adopting significantly lower mixing length parameters l/H_p remove these discrepancies, as seen in other solar type binaries. For the observed metallicity, Granada models with a mixing length of l/H_p=1.30 (primary) and 1.05 (secondary) reproduce both components at a common age of 1.5+-0.6 Gyr. Observations of EF Aqr suggests that magnetic activity, and its effect on envelope convection, is likely to be the cause of discrepancies in both radius and temperature, which can be removed by adjusting the mixing length parameter of the models downwards.Comment: 11 pages, 8 figures, accepted for publication by A&

Long-term changes in the acid and salt concentrations of the Greenland Ice Core Project ice core from electrical stratigraphy

Continuous electrical records covering a climatic cycle are presented for the Greenland Ice Core Project deep ice core from Greenland. Electrical conductivity measurement (ECM) measures the acid content of the ice, and the dielectric profile (DEP) responds to acid, ammonium, and chloride. All features seen can be explained by chemical changes in the ice, and there is no evidence so far for any major change in electrical response with depth or age of the ice. Both records are dominated by the acidity of the ice which varies strongly from acidic in warm periods to alkaline in cold periods, controlled by neutralization by alkaline dust (calcareous and other mineral dust). When Ca is low, the acidity (mainly nitric acid) has a fairly constant background level throughout the cycle, with slightly lower values in ice believed to be from the last interglacial. Ca has to rise only slightly to neutralize the available acidity, so that acidity is a highly nonlinear reflection of climate changes. If neutralization occurred in the aerosol (rather than in the ice), then the number of cloud condensation nuclei over parts of the northern hemisphere could have been reduced, leading to reduced cloud albedo. This nonlinear feedback may have some importance for modeling of climate change. When both acid and ammonium levels are low, the DEP signal can be used to give a rapid indication of chloride trends

Knowledge of learning disabilities: the relationship with choice, duty of care and non-aversive approaches

The present study examines the relationship between the knowledge of the diagnostic criteria for a learning disability (based on DSM IV criteria), care practices and experience in health care and social care staff. Responses to a questionnaire were analysed in terms of participants emphasis on: recognizing duty of care; enabling choice; non-aversive and aversive strategies. Results indicated that the knowledge of the criteria for a learning disability was limited, with only I6% of the sample correctly identifying all three criteria. There were no significant differences between the two groups in relation to experience or level of knowledge. No clear cut differences were found between the groups in relation to tendency to emphasize a particular management approach, with the strategies adopted appearing to be influenced by vignettes used in this study. Participants tended to give responses that identified both a recognition of their duty of care to clients and the need to enable choice. Limitations of this study are discussed

Unzipping Kinetics of Double-Stranded DNA in a Nanopore

We studied the unzipping kinetics of single molecules of double-stranded DNA by pulling one of their two strands through a narrow protein pore. PCR analysis yielded the first direct proof of DNA unzipping in such a system. The time to unzip each molecule was inferred from the ionic current signature of DNA traversal. The distribution of times to unzip under various experimental conditions fit a simple kinetic model. Using this model, we estimated the enthalpy barriers to unzipping and the effective charge of a nucleotide in the pore, which was considerably smaller than previously assumed.Comment: 10 pages, 5 figures, Accepted: Physics Review Letter

Conditional generation of sub-Poissonian light from two-mode squeezed vacuum via balanced homodyne detection on idler mode

A simple scheme for conditional generation of nonclassical light with sub-Poissonian photon-number statistics is proposed. The method utilizes entanglement of signal and idler modes in two-mode squeezed vacuum state generated in optical parametric amplifier. A quadrature component of the idler mode is measured in balanced homodyne detector and only those experimental runs where the absolute value of the measured quadrature is higher than certain threshold are accepted. If the threshold is large enough then the conditional output state of signal mode exhibits reduction of photon-number fluctuations below the coherent-state level.Comment: 7 pages, 6 figures, REVTe

Asiago eclipsing binaries program. I. V432 Aur

The orbit and physical parameters of the previously unsolved eclipsing binary V432 Aur, discovered by Hipparcos, have been derived with errors better than 1% from extensive Echelle spectroscopy and B, V photometry. Synthetic spectral analysis of both components has been performed, yielding T_eff and log g in close agreement with the orbital solution, a metallicity [Z/Z_sun]=-0.60 and rotational synchronization for both components. Direct comparison on the theoretical L, T_eff plane with the Padova evolutionary tracks and isochrones for the masses of the two components (1.22 and 1.08 M_sun) provides a perfect match and a 3.75 Gyr age. The more massive and cooler component is approaching the base of the giant branch and displays a probable pulsation activity with an amplitude of Delta V = 0.075 mag and Delta rad.vel. = 1.5 km/sec. With a T_eff = 6080 K it falls to the red of the nearby instability strip populated by delta Sct and gamma Dor types of pulsating variables. Orbital modeling reveals a large and bright surface spot on it. The pulsations activity and the large spot(s) suggest the presence of macro-turbulent motions in its atmosphere. They reflect in a line broadening that at cursory inspection could be taken as indication of a rotation faster than synchronization, something obviously odd for an old, expanding star.Comment: A&A, 11 pages, accepted Jan 7, 200

Cancer associated auto-antibodies to MUC1 and MUC4 - A blinded case control study of colorectal cancer in UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS)

Recent reports suggest that autoantibodies directed to aberrantly glycosylated mucins, in particular MUC1 and MUC4, are found in patients with colorectal cancer. There is, however, limited information on the autoantibody levels prior to clinical diagnosis, and their utility in cancer screening in the general population. In this study, we have generated O-glycosylated synthetic MUC1 and MUC4 peptides in vitro, to mimic cancer associated glycoforms, and displayed these on microarrays. The assay's performance was tested through an initial screening of serum samples taken from patients at the time of colorectal cancer diagnosis and healthy controls. Subsequently the selected biomarkers were evaluated in a blinded nested case control study, using stored serum samples from among the 50,640 women randomised to the multimodal arm of the UKCTOCS, where women gave annual blood samples for several years. Cases were 97 postmenopausal women who developed colorectal cancer following recruitment, and were age-matched to 97 women without any history of cancer. MUC1-STn and MUC1-Core3 IgG autoantibodies identified cases with 8.2% and 13.4% sensitivity, respectively, at 95% specificity. IgA to MUC4-glycoforms were unable to discriminate between cases and controls in the UKCTOCS sera. Additional analysis was undertaken by combining the data of MUC1-STn and MUC1-Core3 with previously generated data on autoantibodies to p53 peptides, which increased the sensitivity to 32.0% at 95% specificity in the UKCTOCS set. These findings suggest that a combination of antibody signatures may have a role as part of a biomarker panel for the early detection of colorectal cancer

Occupational exposure and markers of genetic damage, systemic inflammation and lung function: a Danish cross-sectional study among air force personnel

Air force ground crew personnel are potentially exposed to fuels and lubricants, as raw materials, vapours and combustion exhaust emissions, during operation and maintenance of aircrafts. This study investigated exposure levels and biomarkers of effects for employees at a Danish air force military base. We enrolled self-reported healthy and non-smoking employees (n = 79) and grouped them by exposure based on job function, considered to be potentially exposed (aircraft engineers, crew chiefs, fuel operators and munition specialists) or as reference group with minimal occupational exposure (avionics and office workers). We measured exposure levels to polycyclic aromatic hydrocarbons (PAHs) and organophosphate esters (OPEs) by silicone bands and skin wipes (PAHs only) as well as urinary excretion of PAH metabolites (OH-PAHs). Additionally, we assessed exposure levels of ultrafine particles (UFPs) in the breathing zone for specific job functions. As biomarkers of effect, we assessed lung function, plasma levels of acute phase inflammatory markers, and genetic damage levels in peripheral blood cells. Exposure levels of total PAHs, OPEs and OH-PAHs did not differ between exposure groups or job functions, with low correlations between PAHs in different matrices. Among the measured job functions, the UFP levels were higher for the crew chiefs. The exposure level of the PAH fluorene was significantly higher for the exposed group than the reference group (15.9 +/- 23.7 ng/g per 24 h vs 5.28 +/- 7.87 ng/g per 24 h, p = 0.007), as was the OPE triphenyl phosphate (305 +/- 606 vs 19.7 +/- 33.8 ng/g per 24 h, p = 0.011). The OPE tris(1, 3-dichlor-2-propyl)phosphate had a higher mean in the exposed group (60.7 +/- 135 ng/g per 24 h) compared to the reference group (8.89 +/- 15.7 ng/g per 24 h) but did not reach significance. No evidence of effects for biomarkers of systemic inflammation, genetic damage or lung function was found. Overall, our biomonitoring study show limited evidence of occupational exposure of air force ground crew personnel to UFPs, PAHs and OPEs. Furthermore, the OH-PAHs and the assessed biomarkers of early biological effects did not differ between exposed and reference groups