A method for estimating the turbulent kinetic energy dissipation rate from a vertically pointing Doppler lidar, and independent evaluation from balloon-borne in situ measurements

A method of estimating dissipation rates from a vertically pointing Doppler lidar with high temporal and spatial resolution has been evaluated by comparison with independent measurements derived from a balloon-borne sonic anemometer. This method utilizes the variance of the mean Doppler velocity from a number of sequential samples and requires an estimate of the horizontal wind speed. The noise contribution to the variance can be estimated from the observed signal-to-noise ratio and removed where appropriate. The relative size of the noise variance to the observed variance provides a measure of the confidence in the retrieval. Comparison with in situ dissipation rates derived from the balloon-borne sonic anemometer reveal that this particular Doppler lidar is capable of retrieving dissipation rates over a range of at least three orders of magnitude. This method is most suitable for retrieval of dissipation rates within the convective well-mixed boundary layer where the scales of motion that the Doppler lidar probes remain well within the inertial subrange. Caution must be applied when estimating dissipation rates in more quiescent conditions. For the particular Doppler lidar described here, the selection of suitably short integration times will permit this method to be applicable in such situations but at the expense of accuracy in the Doppler velocity estimates. The two case studies presented here suggest that, with profiles every 4 s, reliable estimates of ϵ can be derived to within at least an order of magnitude throughout almost all of the lowest 2 km and, in the convective boundary layer, to within 50%. Increasing the integration time for individual profiles to 30 s can improve the accuracy substantially but potentially confines retrievals to within the convective boundary layer. Therefore, optimization of certain instrument parameters may be required for specific implementations

Parental perception of neonatal intensive care in public sector hospitals in South Africa

Background. Little is known about parental experience and decision making with regard to premature  infants requiring intensive care in developing countries. We undertook this study to characterise parents' experience of physician counselling and their role in making life-support decisions for very low-birth-weight (VLBW) (birth weight < 1 501 g) infants born in South Africa's public-sector neonatal intensive care units (NICUs).Methods. Parents of surviving VLBW infants treated in three Johannesburg-area public hospitals and  attending follow-up clinics in August 2001 were interviewed regarding their experience of perinatal  counselling on outcomes (pain, survival, disability), perception of actual and optimal decision making, and satisfaction with NICU communication.Results. Parents of 51 infants were interviewed. Seventy-five per cent of parents reported antenatal counselling by physicians on at least one perinatal topic (severe disability,pain, death, finances or  religious/moral considerations). The majority of parents(> 60%) who received counselling thought that these topics had been discussed adequately. Most parents reported that doctors had the primary  decisionmaking role, either without consulting them (41 %) or after consulting them (37%). Joint decision making was rare (14%). Parents wanted more input in life-support decisions than they reported being given.Conclusion. Counselling is not consistently provided in publicsector hospitals in Johannesburg. Parents  of premature infants want a larger share in NICU decision making than they currently experience. Most parents were satisfied with communication later during their infant's hospitalisation. South Africa presents a unique opportunity to study the use of advanced medical technologies in a nation with marked disparities in access to care.

Genetic variation in the hypothalamic–pituitary–adrenal stress axis influences susceptibility to musculoskeletal pain: results from the EPIFUND study

<b>Objectives</b> To determine if genetic variation in genes in the hypothalamic–pituitary–adrenal (HPA) axis, the primary stress response system, influences susceptibility to developing musculoskeletal pain.<p></p> <b>Methods</b> Pain and comorbidity data was collected at three time points in a prospective population-based cohort study. Pairwise tagging single nucleotide polymorphisms (SNPs) were selected and genotyped for seven genes. Genetic association analysis was carried out using zero-inflated negative binomial regression to test for association between SNPs and the maximum number of pain sites across the three time points in participants reporting pain, reported as proportional changes with 95% CIs. SNPs were also tested for association with chronic widespread pain (CWP) using logistic regression reporting odds ratios and 95% CI.<p></p> <b>Results</b> A total of 75 SNPs were successfully genotyped in 994 participants including 164 cases with persistent CWP and 172 pain-free controls. Multiple SNPs in SERPINA6 were associated with the maximum number of pain sites; for example, each copy of the T allele of rs941601 was associated with having 16% (proportional change=1.16, 95% CI 1.04 to 1.28, p=0.006) more pain sites compared to participants with the CC genotype. SERPINA6 gene SNPs were also associated with CWP. Significant associations between the maximum number of pain sites and SNPs in the CRHBP and POMC genes were also observed and a SNP in MC2R was also associated with CWP. Associations between SNPs and comorbidity of poor sleep quality and depression explained some of the associations observed.<p></p> <b>Conclusions</b> Genetic variation in HPA axis genes was associated with musculoskeletal pain; however, some of the associations were explained by comorbidities. Replication of these findings is required in independent cohorts

Very Large Telescope Observations of the peculiar globular cluster NGC6712. Discovery of a UV, H-alpha excess star in the core

We present results from multi-band observations in the central region of the cluster NGC6712 with the ESO-Very Large Telescope. Using high resolution images we have identified three UV-excess stars. In particular two of them are within the cluster core, a few arcsec apart: the first object is star "S" which previous studies identified as the best candidate to the optical counterpart to the luminous X-ray source detected in this cluster. The other UV object shows clearcut H-alpha emission and, for this reason, is an additional promising interacting binary candidate (a quiescent LMXB or a CV). The presence of two unrelated interacting binary systems a few arcsec apart in the core of this low-density cluster is somewhat surprising and supports the hypothesis that the (internal) dynamical history of the cluster and/or the (external) interaction with the Galaxy might play a fundamental role in the formation of these peculiar objects.Comment: 15 pages, 3 figures. ApJL in pres

Do genetic predictors of pain sensitivity associate with persistent widespread pain?

Genetic risk factors for pain sensitivity may also play a role in susceptibility to chronic pain disorders, in which subjects have low pain thresholds. The aim of this study was to determine if proposed functional single nucleotide polymorphisms (SNPs) in the GTP cyclohydrolase (GCH1) and μ opioid receptor (OPRM1) genes previously associated with pain sensitivity affect susceptibility to chronic widespread pain (CWP). Pain data was collected using body manikins via questionnaire at three time-points over a four year period from subjects aged 25-65 in the North-West of England as part of a population based cohort study, EPIFUND. CWP was defined at each time point using standard criteria. Three SNPs forming a proposed "pain-protective" haplotype in GCH1 (rs10483639, rs3783641 and rs8007267) and two SNPs in OPRM1 (rs1777971 (A118G) and rs563649) were genotyped in cases with persistent CWP (CWP present at ≥2 time-points) and controls who were pain-free at all time-points. The expectation-maximisation algorithm was used to estimate haplotype frequencies. The frequency of the "pain-protective" (CAT - C allele of rs10483639, A allele of rs3783641 and T allele of rs8007267) haplotype was compared to the frequency of the other haplotypes between cases and controls using the χ2 test. Allele frequencies and carriage of the minor allele was compared between cases and controls using χ2 tests for the OPRM1 SNPs. The frequency of the proposed GCH1 "pain-protective" haplotype (CAT) did not significantly differ between cases and controls and no significant associations were observed between the OPRM1 SNPs and CWP. In conclusion, there was no evidence of association between proposed functional SNPs, previously reported to influence pain sensitivity, in GCH1 and OPRM1 with CWP. Further evidence of null association in large independent cohorts is required to truly exclude these SNPs as genetic risk factors for CWP

Problem drug use prevalence estimation revisited:heterogeneity in capture-recapture and the role of external evidence

BACKGROUND AND AIMS: Capture–recapture (CRC) analysis is recommended for estimating the prevalence of problem drug use or people who inject drugs (PWID). We aim to demonstrate how naive application of CRC can lead to highly misleading results, and to suggest how the problems might be overcome. METHODS: We present a case study of estimating the prevalence of PWID in Bristol, UK, applying CRC to lists in contact with three services. We assess: (i) sensitivity of results to different versions of the dominant (treatment) list: specifically, to inclusion of non‐incident cases and of those who were referred directly from one of the other services; (ii) the impact of accounting for a novel covariate, housing instability; and (iii) consistency of CRC estimates with drug‐related mortality data. We then incorporate formally the drug‐related mortality data and lower bounds for prevalence alongside the CRC into a single coherent model. RESULTS: Five of 11 models fitted the full data equally well but generated widely varying prevalence estimates, from 2740 [95% confidence interval (CI) = 2670, 2840] to 6890 (95% CI = 3740, 17680). Results were highly sensitive to inclusion of non‐incident cases, demonstrating the presence of considerable heterogeneity, and were sensitive to a lesser extent to inclusion of direct referrals. A reduced data set including only incident cases and excluding referrals could be fitted by simpler models, and led to much greater consistency in estimates. Accounting for housing stability improved model fit considerably more than did the standard covariates of age and gender. External data provided validation of results and aided model selection, generating a final estimate of the number of PWID in Bristol in 2011 of 2770 [95% credible interval (Cr‐I) = 2570, 3110] or 0.9% (95% Cr‐I = 0.9, 1.0%) of the population aged 15–64 years. CONCLUSIONS: Steps can be taken to reduce bias in capture–recapture analysis, including: careful consideration of data sources, reduction of lists to less heterogeneous subsamples, use of covariates and formal incorporation of external data

\u3ci\u3eFicotylus laselvae\u3c/i\u3e n. sp. (Tylenchomorpha: Anguinidae) associated with \u3ci\u3eFicus colubrinae\u3c/i\u3e in Costa Rica

Ficotylus laselvae n. sp. was recovered from under the bracts of figs (syconia) of Ficus colubrinae from La Selva, Costa Rica, during a survey of nematode rainforest biodiversity and is described herein. This is only the second report of an association between the nematode suborder Tylenchina and the sycones of figs. Previous reports of most nematode associates of the sycones of figs have been from the lumen and involved transmission by female fig wasp pollinators (Agaonidae) during pollination/oviposition (e.g., Schistonchus and Parasitodiplogaster spp.). The association between F. laselvae n. sp. and Ficus colubrinae may involve an invertebrate host, but none was recovered from dissections of the bracts during this study. It is also possible that this is a rainforest understory nematode that feeds ectoparasitically in protected areas on the aerial parts of F. colubrinae. Molecular analysis using near-full-length sequences of the small subunit (SSU) rRNA and D2-D3 expansion segments of the large subunit (LSU) rRNA genes of Ficotylus laselvae n. sp. suggests that it is a member of the suborder Tylenchina (infraorder: Tylenchomorpha; family: Anguinidae) and that the closest sequenced species is F. congestae from the lumen of sycones of Ficus congesta from Queensland, Australia. Although both nematode species are associated with figs, they are morphologically divergent, suggesting that the different micro-niches that they fill provide different selective pressures for evolution of differing morphological characters or they represent different life history morphotypes of a dicyclic genus

The problem of equilibration and the computation of correlation functions on a quantum computer

We address the question of how a quantum computer can be used to simulate experiments on quantum systems in thermal equilibrium. We present two approaches for the preparation of the equilibrium state on a quantum computer. For both approaches, we show that the output state of the algorithm, after long enough time, is the desired equilibrium. We present a numerical analysis of one of these approaches for small systems. We show how equilibrium (time)-correlation functions can be efficiently estimated on a quantum computer, given a preparation of the equilibrium state. The quantum algorithms that we present are hard to simulate on a classical computer. This indicates that they could provide an exponential speedup over what can be achieved with a classical device.Comment: 25 pages LaTex + 8 figures; various additional comments, results and correction