Gas physical conditions and kinematics of the giant outflow Ou4

Ou4 is a recently discovered bipolar outflow with a projected size of more than one degree in the plane of the sky. It is apparently centred on the young stellar cluster -whose most massive representative is the triple system HR8119- inside the HII region Sh 2-129. The driving source, the nature, and the distance of Ou4 are not known. Deep narrow-band imagery of the whole nebula at arcsec resolution was obtained to study its morphology. Long-slit spectroscopy of the tips of the bipolar lobes was secured to determine the gas ionization mechanism, physical conditions, and line-of-sight velocities. An estimate of the proper motions at the tip of the south lobe using archival images is attempted. The existing multi-wavelength data for Sh 2-129 and HR 8119 are also comprehensively reviewed. The morphology of Ou4, its emission-line spatial distribution, line flux ratios, and the kinematic modelling adopting a bow-shock parabolic geometry, illustrate the expansion of a shock-excited fast collimated outflow. The radial velocities and reddening are consistent with those of Sh 2-129 and HR 8119. The improved determination of the distance to HR8119 (composed of two B0 V and one B0.5 V stars) and Sh 2-129 is 712 pc. We identify in WISE images a 5 arcmin-radius (1 pc at the distance above) bubble of emission at 22 micron emitted by hot (107 K) dust, located inside the central part of Ou4 and corresponding to several [O III] features of Ou4. The apparent position and the properties studied in this work are consistent with the hypothesis that Ou4 is located inside the Sh 2-129 HII region, suggesting that it was launched some 90 000 yrs ago by HR8119. The outflow total kinetic energy is estimated to be ~4e47~ergs. However, the alternate possibility that Ou4 is a bipolar planetary nebula, or the result of an eruptive event on a massive AGB or post-AGB star not yet identified, cannot be ruled out.Comment: Accepted for publication in Astronomy and Astrophysics. Also available at http://hal.archives-ouvertes.fr/hal-0102228

Half-life of cost-of-illness estimates: the case of Spina Bifida

ManuscriptNeural tube defects, which include spina bifida, are one of the most frequent and important categories of birth defects. Accordingly, there has been considerable interest in studying the impact of spina bifida as a public health problem. This impact can be measured in various ways, including disease-specific mortality, morbidity, functional limitation or disability, and quality of life impairment. Each of these measures captures one component of the total burden of disease. Such measures of impact are important because they allow public health agencies, researchers, and health care providers to understand the effects of preventive or diagnostic interventions, changes in disease incidence or prevalence, and new technologies

A novel method to selectively elicit cold sensations without touch

BACKGROUND: Thermal and tactile stimuli are transduced by different receptor classes. However, mechano- and thermo-sensitive afferents interact at spinal and supraspinal levels. Yet, most studies on responses to cooling stimuli are confounded by mechanical contact, making these interactions difficult to isolate. Methods for precise control of non-mechanical thermal stimulations remain challenging, particularly in the cold range. NEW METHOD: We developed a non-tactile, focal, temperature-controlled, multi-purpose cooling stimulator. This method controls the exposure of a target skin region to a dry-ice source. Using a thermal camera to monitor skin temperature, and adjusting the source-skin distance accordingly, we could deliver non-tactile cooling stimuli with customisable profiles, for studying different aspects of cold sensation. RESULTS: To validate our method, we measured absolute and relative thresholds for cold sensation without mechanical contact in 13 human volunteer participants, using the method of limits. We found that the absolute cold detection threshold was 32.71oC ± 0.88oC. This corresponded to a threshold relative to each participant's baseline skin temperature of -1.08oC ± 0.37oC. COMPARISONS WITH EXISTING METHOD: Our method allows cooling stimulation without the confound of mechanical contact, in a controllable and focal manner. CONCLUSIONS: We report a non-contact cooling stimulator and accompanying control system. We used this to measure cold thresholds in the absence of confounding touch. Our method enables more targeted studies of both cold sensory pathways, and of cold-touch interactions

Analytic distribution of the optimal cross-correlation statistic for stochastic gravitational-wave-background searches using pulsar timing arrays

We show via both analytical calculation and numerical simulation that the optimal cross-correlation statistic (OS) for stochastic gravitational-wave-background (GWB) searches using data from pulsar timing arrays follows a generalized chi-squared (GX2) distribution-i.e., a linear combination of chi-squared distributions with coefficients given by the eigenvalues of the quadratic form defining the statistic. This observation is particularly important for calculating the frequentist statistical significance of a possible GWB detection, which depends on the exact form of the distribution of the OS signal-to-noise ratio (S/N) $\hat\rho \equiv \hat A_{\rm gw}^2/\sigma_0$ in the absence of GW-induced cross correlations (i.e., the null distribution). Previous discussions of the OS have incorrectly assumed that the analytic null distribution of $\hat\rho$ is well-approximated by a zero-mean unit-variance Gaussian distribution. Empirical calculations show that the null distribution of $\hat\rho$ has "tails" which differ significantly from those for a Gaussian distribution, but which follow (exactly) a GX2 distribution. So, a correct analytical assessment of the statistical significance of a potential detection requires the use of a GX2 distribution.Comment: 13 pages, 3 Figure

Computer-aided Detection in Computed Tomography Colonography with Full Fecal Tagging: Comparison of Standalone Performance of 3 Automated Polyp Detection Systems

AbstractPurposeWe sought to compare the performance of 3 computer-aided detection (CAD) polyp algorithms in computed tomography colonography (CTC) with fecal tagging.MethodsCTC data sets of 33 patients were retrospectively analysed by 3 different CAD systems: system 1, MedicSight; system 2, Colon CAD; and system 3, Polyp Enhanced View. The polyp database comprised 53 lesions, including 6 cases of colorectal cancer, and was established by consensus reading and comparison with colonoscopy. Lesions ranged from 6-40 mm, with 25 lesions larger than 10 mm in size. Detection and false-positive (FP) rates were calculated.ResultsCAD systems 1 and 2 could be set to have varying sensitivities with higher FP rates for higher sensitivity levels. Sensitivities for system 1 ranged from 73%–94% for all lesions (78%–100% for lesions ≥10 mm) and, for system 2, from 64%–94% (78%–100% for lesions ≥10 mm). System 3 reached an overall sensitivity of 76% (100% for lesions ≥10 mm). The mean FP rate per patient ranged from 8–32 for system 1, from 1–8 for system 2, and was 5 for system 3. At the highest sensitivity level for all polyps (94%), system 2 showed a statistically significant lower FP rate compared with system 1 (P = .001). When analysing lesions ≥10 mm, system 3 had significantly fewer FPs than systems 1 and 2 (P < .012).ConclusionsStandalone CTC-CAD analysis in the selected patient collective showed the 3 systems tested to have a variable but overall promising performance with respect to sensitivity and the FP rate

How many diagnosis fields are needed to capture safety events in administrative data? Findings and recommendations from the WHO ICD-11 Topic Advisory Group on Quality and Safety

Objective As part of the WHO ICD-11 development initiative, the Topic Advisory Group on Quality and Safety explores meta-features of morbidity data sets, such as the optimal number of secondary diagnosis fields. Design The Health Care Quality Indicators Project of the Organization for Economic Co-Operation and Development collected Patient Safety Indicator (PSI) information from administrative hospital data of 19-20 countries in 2009 and 2011. We investigated whether three countries that expanded their data systems to include more secondary diagnosis fields showed increased PSI rates compared with six countries that did not. Furthermore, administrative hospital data from six of these countries and two American states, California (2011) and Florida (2010), were analysed for distributions of coded patient safety events across diagnosis fields. Results Among the participating countries, increasing the number of diagnosis fields was not associated with any overall increase in PSI rates. However, high proportions of PSI-related diagnoses appeared beyond the sixth secondary diagnosis field. The distribution of three PSI-related ICD codes was similar in California and Florida: 89-90% of central venous catheter infections and 97-99% of retained foreign bodies and accidental punctures or lacerations were captured within 15 secondary diagnosis fields. Conclusions Six to nine secondary diagnosis fields are inadequate for comparing complication rates using hospital administrative data; at least 15 (and perhaps more with ICD-11) are recommended to fully characterize clinical outcomes. Increasing the number of fields should improve the international and intra-national comparability of data for epidemiologic and health services research, utilization analyses and quality of care assessmen

Evidence of Two Functionally Distinct Ornithine Decarboxylation Systems in Lactic Acid Bacteria

Biogenic amines are low-molecular-weight organic bases whose presence in food can result in health problems. The biosynthesis of biogenic amines in fermented foods mostly proceeds through amino acid decarboxylation carried out by lactic acid bacteria (LAB), but not all systems leading to biogenic amine production by LAB have been thoroughly characterized. Here, putative ornithine decarboxylation pathways consisting of a putative ornithine decarboxylase and an amino acid transporter were identified in LAB by strain collection screening and database searches. The decarboxylases were produced in heterologous hosts and purified and characterized in vitro, whereas transporters were heterologously expressed in Lactococcus lactis and functionally characterized in vivo. Amino acid decarboxylation by whole cells of the original hosts was determined as well. We concluded that two distinct types of ornithine decarboxylation systems exist in LAB. One is composed of an ornithine decarboxylase coupled to an ornithine/putrescine transmembrane exchanger. Their combined activities results in the extracellular release of putrescine. This typical amino acid decarboxylation system is present in only a few LAB strains and may contribute to metabolic energy production and/or pH homeostasis. The second system is widespread among LAB. It is composed of a decarboxylase active on ornithine and L-2,4-diaminobutyric acid (DABA) and a transporter that mediates unidirectional transport of ornithine into the cytoplasm. Diamines that result from this second system are retained within the cytosol.