Using 21-cm absorption surveys to measure the average HI spin temperature in distant galaxies

We present a statistical method for measuring the average HI spin temperature in distant galaxies using the expected detection yields from future wide-field 21cm absorption surveys. As a demonstrative case study we consider a simulated all-southern-sky survey of 2-h per pointing with the Australian Square Kilometre Array Pathfinder for intervening HI absorbers at intermediate cosmological redshifts between $z = 0.4$ and $1$. For example, if such a survey yielded $1000$ absorbers we would infer a harmonic-mean spin temperature of $\overline{T}_\mathrm{spin} \sim 100$K for the population of damped Lyman $\alpha$ (DLAs) absorbers at these redshifts, indicating that more than $50$ per cent of the neutral gas in these systems is in a cold neutral medium (CNM). Conversely, a lower yield of only 100 detections would imply $\overline{T}_\mathrm{spin} \sim 1000$K and a CNM fraction less than $10$ per cent. We propose that this method can be used to provide independent verification of the spin temperature evolution reported in recent 21cm surveys of known DLAs at high redshift and for measuring the spin temperature at intermediate redshifts below $z \approx 1.7$, where the Lyman-$\alpha$ line is inaccessible using ground-based observatories. Increasingly more sensitive and larger surveys with the Square Kilometre Array should provide stronger statistical constraints on the average spin temperature. However, these will ultimately be limited by the accuracy to which we can determine the HI column density frequency distribution, the covering factor and the redshift distribution of the background radio source population.Comment: 11 pages, 9 figures, 1 table. Proof corrected versio

Giant Fluctuations of Coulomb Drag in a Bilayer System

We have observed reproducible fluctuations of the Coulomb drag, both as a function of magnetic field and electron concentration, which are a manifestation of quantum interference of electrons in the layers. At low temperatures the fluctuations exceed the average drag, giving rise to random changes of the sign of the drag. The fluctuations are found to be much larger than previously expected, and we propose a model which explains their enhancement by considering fluctuations of local electron properties.Comment: 10 pages, 4 figure

Marketing a healthier choice: exploring young people’s perception of e-cigarettes

Background: As a consequence of insufficient evidence on the safety and efficacy of e cigarettes, there has been much controversy surrounding its use in the tobacco control field. Objectives: We sought to examine smoking prevalence and salience of e-cigarettes marketing stimuli, and whether these affected attitude-relevant responses toward e-cigarettes and intention to vape. Methodology: A convenience sampling procedure was used to recruit 436 ever- and never-smokers aged 18 or older in the UK. Correlation analysis and structural equation modelling tested direct and indirect relationships between salience of e-cigarettes marketing messages, attitude relevant variables, and intention to vape. Results: Just over half of never-smokers were females compared to two-thirds of ever-smokers who were males. Majority of respondents comprising 56% of ever-smokers and 63% of never-smokers had seen e-cigarette promotion in stores or gas stations. Only a third or less of ever- and never-smokers had seen e-cigarette promotion on TV, newspaper or online. Among never-smokers, association between e-cigarette promotion awareness and intention to vape was significant (B= .59, p < .001) but this was mediated by conative beliefs (B=.84, p =.05). Among ever-smokers, awareness of e-cigarette significantly affected cognitive (B= .97, p =.01) and conative attitudes (B= .88, p =.001), which in turn affected intention to vape in future (B= .45, p < .001). Conclusions: Our results suggest that never-smokers might think of vaping instead of smoking cigarettes in future. Likewise, ever-smokers might have intention to vape if they think favourably about promotional stimuli and develop positive emotions towards vaping. Our study supports the need for more scientific evidence on the efficacy of e-cigarettes to encourage vaping as a substitute to smoking

Reconstruction of deglacial sea surface temperatures in the tropical Pacific from selective analysis of a fossil coral

The Sr/Ca of coral skeletons demonstrates potential as an indicator of sea surface temperatures (SSTs). However, the glacial-interglacial SST ranges predicted from Sr/Ca of fossil corals are usually higher than from other marine proxies. We observed infilling of secondary aragonite, characterised by high Sr/Ca ratios, along intraskeletal pores of a fossil coral from Papua New Guinea that grew during the penultimate deglaciation (130 +/- 2 ka). Selective microanalysis of unaltered areas of the fossil coral indicates that SSTs at similar to 130 ka were &lt;= 1 degrees C cooler than at present in contrast with bulk measurements ( combining infilled and unaltered areas) which indicate a difference of 6-7 degrees C. The analysis of unaltered areas of fossil skeletons by microprobe techniques may offer a route to more accurate reconstruction of past SSTs.</p

Attitudinal and normative responses to advertising stimuli and vaping intentions

Empirical data to show whether exposure to e-cigarette advertising stimuli may influence former- and never-smokers to consider vaping is lacking. We examined whether former- and never-smokers’ cognitive, affective, and normative responses to e-cigarette stimuli in retail outlets will predict their vaping intention. A repeat cross-sectional study recruited 876 participants aged 18–24 years at Waves 1 and 2 in the United Kingdom. Bayesian structural equation modeling tested mediation and moderation effects of the variables of interest. Results from Waves 1 and 2 revealed that the association of salience of e-cigarette advertising in stores and gas stations with vaping intention was mediated by affect and subjective norms among former smokers. Cognitive attitudes of never smokers mediated the relationship between salience of e-cigarette advertising in retail outlets and vaping intention at Waves 1 and 2. Former smokers were more likely to hold stronger affect toward vaping than never smokers at Wave 2. Our study supports the need for stronger policies to restrict e-cigarette portrayals in retail outlets, as advertising messages can trigger strong thoughts, feelings, and norms of vaping. Interventions may benefit from including attitudinal and normative components to promote pro-social behavior

Complement C3 serum levels in anorexia nervosa: a potential biomarker for the severity of disease?

BackgroundAnorexia nervosa carries the highest mortality rate of any psychiatric disorder. Even the most critically ill anorexic patients may present with normal 'standard' laboratory values, underscoring the need for a new sensitive biomarker. The complement cascade, a major component of innate immunity, represents a driving force in the pathophysiology of multiple inflammatory disorders. The role of complement in anorexia nervosa remains poorly understood. The present study was designed to evaluate the role of complement C3 levels, the extent of complement activation and of complement hemolytic activity in serum, as potential new biomarkers for the severity of anorexia nervosa.Patients and methodsThis was a prospective cohort study on 14 patients with severe anorexia nervosa, as defined by a body mass index (BMI) &lt;14 kg/m2. Serum samples were obtained in a biweekly manner until hospital discharge. A total of 17 healthy subjects with normal BMI values served as controls. The serum levels of complement C3, C3a, C5a, sC5b-9, and of the 50% hemolytic complement activity (CH50) were quantified and correlated with the BMIs of patients and control subjects.ResultsSerum C3 levels were significantly lower in patients with anorexia nervosa than in controls (median 3.7 (interquartile range (IQR) 2.5-4.9) vs 11.4 (IQR 8.9-13.7, P &lt;0.001). In contrast, complement activation fragments and CH50 levels were not significantly different between the two groups. There was a strong correlation between index C3 levels and BMI (Spearman correlation coefficient = 0.71, P &lt;0.001).ConclusionsComplement C3 serum levels may represent a sensitive new biomarker for monitoring the severity of disease in anorexia nervosa. The finding from this preliminary pilot study will require further investigation in future prospective large-scale multicenter trials

Tuning the electrically evaluated electron Lande g factor in GaAs quantum dots and quantum wells of different well widths

We evaluate the Lande g factor of electrons in quantum dots (QDs) fabricated from GaAs quantum well (QW) structures of different well width. We first determine the Lande electron g factor of the QWs through resistive detection of electron spin resonance and compare it to the enhanced electron g factor determined from analysis of the magneto-transport. Next, we form laterally defined quantum dots using these quantum wells and extract the electron g factor from analysis of the cotunneling and Kondo effect within the quantum dots. We conclude that the Lande electron g factor of the quantum dot is primarily governed by the electron g factor of the quantum well suggesting that well width is an ideal design parameter for g-factor engineering QDs

Sexual well-being and diurnal cortisol after prostate cancer treatment.

Sexual dysfunction and psychological distress are common after prostate cancer. Research has not examined the role of neuroendocrine markers of stress (e.g. cortisol). This study examines whether sexual functioning or sexual bother is associated with diurnal cortisol. Men treated for prostate cancer completed the University of California-Los Angeles Prostate Cancer Index and provided saliva samples four times daily for cortisol assessment. Higher sexual bother, but not sexual functioning, was associated with steeper cortisol slope. Better sexual functioning, and not sexual bother, was significantly associated with the cortisol awakening response. Assessment of stress and stress-reducing interventions might be warranted in sexual rehabilitation after prostate cancer