The Relation Between the Surface Brightness and the Diameter for Galactic Supernova Remnants

In this work, we have constructed a relation between the surface brightness ($\Sigma$) and diameter (D) of Galactic C- and S-type supernova remnants (SNRs). In order to calibrate the $\Sigma$-D dependence, we have carefully examined some intrinsic (e.g. explosion energy) and extrinsic (e.g. density of the ambient medium) properties of the remnants and, taking into account also the distance values given in the literature, we have adopted distances for some of the SNRs which have relatively more reliable distance values. These calibrator SNRs are all C- and S-type SNRs, i.e. F-type SNRs (and S-type SNR Cas A which has an exceptionally high surface brightness) are excluded. The Sigma-D relation has 2 slopes with a turning point at D=36.5 pc: $\Sigma$(at 1 GHz)=8.4$^{+19.5}_{-6.3}$$\times10^{-12}$ D$^{{-5.99}^{+0.38}_{-0.33}}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ (for $\Sigma$$\le3.7\times10^{-21}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ and D$\ge$36.5 pc) and $\Sigma$(at 1 GHz)=2.7$^{+2.1}_{-1.4}$$\times$ 10$^{-17}$ D$^{{-2.47}^{+0.20}_{-0.16}}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ (for $\Sigma$$>3.7\times10^{-21}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ and D$<$36.5 pc). We discussed the theoretical basis for the $\Sigma$-D dependence and particularly the reasons for the change in slope of the relation were stated. Added to this, we have shown the dependence between the radio luminosity and the diameter which seems to have a slope close to zero up to about D=36.5 pc. We have also adopted distance and diameter values for all of the observed Galactic SNRs by examining all the available distance values presented in the literature together with the distances found from our $\Sigma$-D relation.Comment: 45 pages, 2 figures, accepted for publication in Astronomical and Astrophysical Transaction

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate.In seven subjects mean arterial blood pressure was lowered (≈8 mmHg) and then raised (≈13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve).Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 ± 3 to 92 ± 4 beats min−1; P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 ± 4 to 68 ± 4 beats min−1; P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects.Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition.These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals

The carbon inventory in a quiescent, filamentary molecular cloud in G328

Extent: 8 p.We present spectral line images of [C I] 809 GHz, CO J = 1-0 115 GHz and H I 1.4 GHz line emission, and calculate the corresponding C, CO and H column densities, for a sinuous, quiescent giant molecular cloud about 5 kpc distant along the l = 328° sightline (hereafter G328) in our Galaxy. The [C I] data comes from the High Elevation Antarctic Terahertz telescope, a new facility on the summit of the Antarctic plateau where the precipitable water vapor falls to the lowest values found on the surface of the Earth. The CO and H I data sets come from the Mopra and Parkes/ATCA telescopes, respectively. We identify a filamentary molecular cloud, ~75 × 5 pc long with mass ~4 × 104 M ☉ and a narrow velocity emission range of just 4 km s–1. The morphology and kinematics of this filament are similar in CO, [C I], and H I, though in the latter appears as self-absorption. We calculate line fluxes and column densities for the three emitting species, which are broadly consistent with a photodissociation region model for a GMC exposed to the average interstellar radiation field. The [C/CO] abundance ratio averaged through the filament is found to be approximately unity. The G328 filament is constrained to be cold (T Dust < 20 K) by the lack of far-IR emission, to show no clear signs of star formation, and to only be mildly turbulent from the narrow line width. We suggest that it may represent a GMC shortly after formation, or perhaps still in the process of formation.Michael G. Burton, Michael C. B. Ashley, Catherine Braiding, John W. V. Storey, Craig Kulesa, David J. Hollenbach, Mark Wolfire, Christian Glück and Gavin Rowel

Exercise-induced arterial hypoxaemia in healthy young women

We questioned whether exercise-induced arterial hypoxaemia (EIAH) occurs in healthy active women, who have smaller lungs, reduced lung diffusion, and lower maximal O2 consumption rate () than age- and height-matched men.Twenty-nine healthy young women with widely varying fitness levels ( 57 ± 6 ml kg−1 min−1; range, 35–70 ml kg−1 min−1; or 148 ± 5 %; range, 93–188 % predicted) and normal resting lung function underwent an incremental treadmill test to during the follicular phase of their menstrual cycle. Arterial blood samples were taken at rest and near the end of each workload.Arterial PO2 (Pa,O2) decreased > 10 mmHg below rest in twenty-two of twenty-nine subjects at (Pa,O2, 77.5 ± 0.9 mmHg; range, 67–88 mmHg; arterial O2 saturation (Sa,O2), 92.3 ± 0.2 %; range, 87–94 %). The remaining seven subjects maintained Pa,O2 within 10 mmHg of rest. Pa,O2 at was inversely related to the alveolar to arterial O2 difference (A-aDO2) (r = -0.93; 35–52 mmHg) and to arterial PCO2 (Pa,CO2) (r = -0.62; 26–39 mmHg).EIAH was inversely related to (r = -0.49); however, there were many exceptions. Almost half of the women with significant EIAH had within 15 % of predicted normal values ( 40–55 ml kg−1 min−1); among subjects with very high (55–70 ml kg−1 min−1), the degree of excessive A-aDO2 and EIAH varied markedly (e.g. A-aDO2, 30–50 mmHg; Pa,O2, 68–91 mmHg).In the women with EIAH at many began to experience an excessive widening of their A-aDO2 during moderate intensity exercise, which when combined with a weak ventilatory response, led to a progressive hypoxaemia. Inactive, less fit subjects had no EIAH and narrower A-aDO2 when compared with active, fitter subjects at the same (40–50 ml kg−1 min−1).These data demonstrate that many active healthy young women experience significant EIAH, and at a that is substantially less than those in their active male contemporaries. The onset of EIAH during submaximal exercise, and/or its occurrence at a relatively low implies that lung structure/function subserving alveolar to arterial O2 transport is abnormally compromised in many of these habitually active subjects