The Conditions Necessary for the Absorption of Ultra-Short Waves in Hydrogen

A review is given of the work published to date on the absorption of ultra-short radio waves in excited hydrogen. A fairly detailed quantum mechanical analysis is given of the whole problem of intensity ratios for the Balmer line components. Theoretical intensity ratios are calculated; and the application of these results to the experimental problem is pointed out, together with the necessity for making preliminary investigations of the experiment values of these ratios. The experiment described measured the values of the intensity ratios for Hα and Hβ at five different pressures, by means an analysis with a spectrograph crossed with a Fabry-Perot interferometer. A discussion is given of the significance of the measured values, and from them predictions have been made concerning the probable success of an experiment to measure the absorption of ultra-short waves in hydrogen.</p

Effect of the Newhints home-visits intervention on neonatal mortality rate and care practices in Ghana: a cluster randomised controlled trial.

BACKGROUND: In 2009, on the basis of promising evidence from trials in south Asia, WHO and UNICEF issued a joint statement about home visits as a strategy to improve newborn survival. In the Newhints trial, we aimed to test this home-visits strategy in sub-Saharan Africa by assessing the effect on all-cause neonatal mortality rate (NMR) and essential newborn-care practices. METHODS: The Newhints cluster randomised trial was undertaken in 98 zones in seven districts in the Brong Ahafo Region, Ghana. 49 zones were randomly assigned to the Newhints intervention and 49 to the control intervention by use of restricted randomisation with stratification to ensure comparability between interventions. Community-based surveillance volunteers (CBSVs) in Newhints zones were trained to identify pregnant women in their community and to make two home visits during pregnancy and three in the first week of life to promote essential newborn-care practices, weigh and assess babies for danger signs, and refer as necessary. Primary outcomes were NMR and coverage of key essential newborn-care practices. Analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00623337. FINDINGS: 16,168 (99%) of 16,329 deliveries between November, 2008, and December, 2009, were livebirths; the status at 1 month was known for 15,619 (97%) livebirths. 482 neonatal deaths were recorded. Coverage data were available from 6029 women in Newhints zones; of these 4358 (72%) reported having CBSV visits during pregnancy and 3815 (63%) reported having postnatal visits. This coverage increased substantially from June, 2009, after the introduction of new implementation strategies and reached almost 90% for pregnancy visits by the end of the trial and 75% for postnatal visits. The Newhints intervention significantly increased coverage of key essential newborn-care behaviours, except for four or more antenatal-care visits (5975 [76%] of 7859 vs 5988 [74%] of 8121, respectively; relative risk 1·02, 95% CI 0·96-1·09; p=0·52) and baby delivered in a facility (5373 [68%] vs 5539 [68%], respectively; 0·97, 0·81-1·14; p=0·69). The largest increase was for care-seeking, with 102 (77%) of 132 sick babies in Newhints zones taken to a hospital or clinic compared with 77 (55%) of 139 in control zones (1·43, 1·17-1·76; p=0·001). Increases were also noted in bednet use during pregnancy (5398 [69%] of 7859 vs 5135 [63%] of 8121, respectively; 1·12, 1·03-1·21; p=0·005), money saved for delivery or emergency (5730 [86%] of 6681 vs 5525 [80%] of 6941, respectively; 1·09, 1·05-1·12; p<0·0001), transport arranged in advance for facility (2496 [37%] vs 2061 [30%], respectively; 1·30, 1·12-1·49; p=0·0004), birth assistant for home delivery washed hands with soap (1853 [93%] of 1992 vs 1817 [87%] of 2091, respectively; 1·05, 1·02-1·09; p=0·001), initiation of breastfeeding in less than 1 h of birth (3743 [49%] of 7673 vs 3280 [41%] of 7921, respectively; 1·22, 1·07-1·40; p=0·004), skin to skin contact (3355 [44%] vs 1931 [24%], respectively; 2·30, 1·85-2·87; p=0·0002), first bath delayed for longer than 6 h (3131 [41%] vs 2269 [29%], respectively; 1·65, 1·27-2·13; p<0·0001), exclusive breastfeeding for 26-32 days (1217 [86%] of 1414 vs 1091 [80%] of 1371; 1·10, 1·04-1·16; p=0·001), and baby sleeping under bednet for 8-56 days (4548 [79%] of 5756 vs 4291 [73%] of 5846; 1·09, 1·03-1·15; p=0·002). There were 230 neonatal deaths in the Newhints zones compared with 252 in the control zones. The overall NMRs per 1000 livebirths were 29·8 and 31·9, respectively (0·92, 0·75-1·12; p=0·405). INTERPRETATION: The reduction in NMR with Newhints is consistent with the reductions achieved in three trials undertaken in programme settings in south Asia. Because there is no suggestion of any heterogeneity (p=0·850) between these trials and Newhints, the meta-analysis summary estimate of a reduction of 12% (95% CI 5-18) provides the best evidence for the likely effect of the home-visits strategy delivered within programmes in sub-Saharan Africa and in south Asia. Improvements in the quality of delivery and neonatal care in health facilities and development of innovative, effective strategies to increase coverage of home visits on the day of birth could lead to the achievement of more substantial reductions. FUNDING: WHO, Bill & Melinda Gates Foundation, and UK Department for International Development

The one-component plasma: a conceptual approach

The one-component plasma (OCP) represents the simplest statistical mechanical model of a Coulomb system. For this reason, it has been extensively studied over the last forty years. The advent of the integral equations has resulted in a dramatic improvement in our ability to carry out numerical calculations, but came at the expense of a physical insight gained in a simpler analytic theory. In this paper we present an extension of the Debye-Hueckel (DH) theory to the OCP. The theory allows for analytic calculations of all the thermodynamic functions, as well as the structure factor. The theory explicitly satisfies the Stillinger-Lovett and, for small couplings, the compressibility sum rules, implying its internal self consistency.Comment: 28 pages, 5 Postscript figures, uses elsart.sty, accepted for publication in Physica

A modified and automated version of the 'Fluorimetric Detection of Alkaline DNA Unwinding' method to quantify formation and repair of DNA strand breaks

<p>Abstract</p> <p>Background</p> <p>Formation and repair of DNA single-strand breaks are important parameters in the assessment of DNA damage and repair occurring in live cells. The 'Fluorimetric Detection of Alkaline DNA Unwinding (FADU)' method [Birnboim HC, Jevcak JJ. Cancer Res (1981) 41:1889–1892] is a sensitive procedure to quantify DNA strand breaks, yet it is very tedious to perform.</p> <p>Results</p> <p>In order (i) to render the FADU assay more convenient and robust, (ii) to increase throughput, and (iii) to reduce the number of cells needed, we have established a modified assay version that is largely automated and is based on the use of a liquid handling device. The assay is operated in a 96-well format, thus greatly increasing throughput. The number of cells required has been reduced to less than 10,000 per data point. The threshold for detection of X-ray-induced DNA strand breaks is 0.13 Gy. The total assay time required for a typical experiment to assess DNA strand break repair is 4–5 hours.</p> <p>Conclusion</p> <p>We have established a robust and convenient method measuring of formation and repair of DNA single-strand breaks in live cells. While the sensitivity of our method is comparable to current assays, throughput is massively increased while operator time is decreased.</p

A Multiscale Approach to Determination of Thermal Properties and Changes in Free Energy: Application to Reconstruction of Dislocations in Silicon

We introduce an approach to exploit the existence of multiple levels of description of a physical system to radically accelerate the determination of thermodynamic quantities. We first give a proof of principle of the method using two empirical interatomic potential functions. We then apply the technique to feed information from an interatomic potential into otherwise inaccessible quantum mechanical tight-binding calculations of the reconstruction of partial dislocations in silicon at finite temperature. With this approach, comprehensive ab initio studies at finite temperature will now be possible.Comment: 5 pages, 3 figure

Cost and cost-eff ectiveness of newborn home visits: fi ndings from the Newhints cluster-randomised controlled trial in rural Ghana

Background Every year, 2·9 million newborn babies die worldwide. A meta-analysis of four cluster-randomised controlled trials estimated that home visits by trained community members in programme settings in Ghana and south Asia reduced neonatal mortality by 12% (95% CI 5–18). We aimed to estimate the costs and cost-eff ectiveness of newborn home visits in a programme setting. Methods We prospectively collected detailed cost data alongside the Newhints trial, which tested the eff ect of a homevisits intervention in seven districts in rural Ghana and showed a reduction of 8% (95% CI –12 to 25%) in neonatal mortality. The intervention consisted of a package of home visits to pregnant women and their babies in the fi rst week of life by community-based surveillance volunteers. We calculated incremental cost-eff ectiveness ratios (ICERs) with Monte Carlo simulation and one-way sensitivity analyses and characterised uncertainty with cost-eff ectiveness planes and cost-eff ectiveness acceptability curves. We then modelled the potential cost-eff ectiveness for baseline neonatal mortality rates of 20–60 deaths per 1000 livebirths with use of a meta-analysis of eff ectiveness estimates. Findings In the 49 zones randomly allocated to receive the Newhints intervention, a mean of 407 (SD 18) communitybased surveillance volunteers undertook home visits for 7848 pregnant women who gave birth to 7786 live babies in 2009. Annual economic cost of implementation was US$203 998, or$0·53 per person. In the base-case analysis, the Newhints intervention cost a mean of $10 343 (95$352 (95% CI 104 to –268) per discounted life-year saved, and had a 72% chance of being highly cost eff ective with respect to Ghana’s 2009 gross domestic product per person. Key determinants of cost-eff ectiveness were the discount rate, protective eff ectiveness, baseline neonatal mortality rate, and implementation costs. In the scenarios modelled with the meta-analysis results, the ICER increased from $127 per life-year saved at a neonatal mortality rate of 60 deaths per 1000 livebirths, to$379 per life-year saved at a rate of 20 deaths per 1000 livebirths. The strategy had at least a 99% probability of being highly cost eff ective for lower-middle-income countries in all neonatal mortality rate scenarios modelled, and at least a 95% probability of being highly cost eff ective for low-income countries at neonatal mortality rates of 30 or more deaths per 1000 livebirths. Interpretation Our fi ndings show that the seemingly modest mortality reductions achieved by a newborn home-visit strategy might in fact be cost eff ective. In Ghana, such strategies are also likely to be aff ordable. Our fi ndings support recommendations from WHO and UNICEF that low-income and middle-income countries implement newborn home visits

Social group size affects Mycobacterium bovis infection in European badgers (Meles meles)

1. In most social animals, the prevalence of directly transmitted pathogens increases in larger groups and at higher population densities. Such patterns are predicted by models of Mycobacterium bovis infection in European badgers (Meles meles). 2. We investigated the relationship between badger abundance and M. bovis prevalence, using data on 2696 adult badgers in 10 populations sampled at the start of the Randomized Badger Culling Trial. 3. M. bovis prevalence was consistently higher at low badger densities and in small social groups. M. bovis prevalence was also higher among badgers whose genetic profiles suggested that they had immigrated into their assigned social groups. 4. The association between high M. bovis prevalence and small badger group size appeared not to have been caused by previous small-scale culling in study areas, which had been suspended, on average, 5 years before the start of the current study. 5. The observed pattern of prevalence might occur through badgers in smaller groups interacting more frequently with members of neighbouring groups; detailed behavioural data are needed to test this hypothesis. Likewise, longitudinal data are needed to determine whether the size of infected groups might be suppressed by disease-related mortality. 6. Although M. bovis prevalence was lower at high population densities, the absolute number of infected badgers was higher. However, this does not necessarily mean that the risk of M. bovis transmission to cattle is highest at high badger densities, since transmission risk depends on badger behaviour as well as on badger density

Hydrodynamic Synchronisation of Model Microswimmers

We define a model microswimmer with a variable cycle time, thus allowing the possibility of phase locking driven by hydrodynamic interactions between swimmers. We find that, for extensile or contractile swimmers, phase locking does occur, with the relative phase of the two swimmers being, in general, close to 0 or pi, depending on their relative position and orientation. We show that, as expected on grounds of symmetry, self T-dual swimmers, which are time-reversal covariant, do not phase-lock. We also discuss the phase behaviour of a line of tethered swimmers, or pumps. These show oscillations in their relative phases reminiscent of the metachronal waves of cilia.Comment: 17 pages, 8 figure

Clusters and Fluctuations at Mean-Field Critical Points and Spinodals

We show that the structure of the fluctuations close to spinodals and mean-field critical points is qualitatively different than the structure close to non-mean-field critical points. This difference has important implications for many areas including the formation of glasses in supercooled liquids. In particular, the divergence of the measured static structure function in near-mean-field systems close to the glass transition is suppressed relative to the mean-field prediction in systems for which a spatial symmetry is broken.Comment: 5 pages, 1 figur

Competence of health workers in emergency obstetric care : an assessment using clinical vignettes in Brong Ahafo region, Ghana

Objectives To assess health worker competence in emergency obstetric care using clinical vignettes, to link competence to availability of infrastructure in facilities, and to average annual delivery workload in facilities. Design Cross-sectional Health Facility Assessment linked to population-based surveillance data. Setting 7 districts in Brong Ahafo region, Ghana. Participants Most experienced delivery care providers in all 64 delivery facilities in the 7 districts. Primary outcome measures Health worker competence in clinical vignette actions by cadre of delivery care provider and by type of facility. Competence was also compared with availability of relevant drugs and equipment, and to average annual workload per skilled birth attendant. Results Vignette scores were moderate overall, and differed significantly by respondent cadre ranging from a median of 70% correct among doctors, via 55% among midwives, to 25% among other cadres such as health assistants and health extension workers (p Conclusions Lack of competence might limit clinical practice even more than lack of relevant drugs and equipment. Cadres other than midwives and doctors might not be able to diagnose and manage delivery complications. Checking clinical competence through vignettes in addition to checklist items could contribute to a more comprehensive approach to evaluate quality of care.Peer reviewe