Abstract
Observing nearby galaxies with submillimeter telescopes on the ground has two major challenges. First, the brightness is significantly reduced at long submillimeter wavelengths compared to ...the brightness at the peak of the dust emission. Second, it is necessary to use a high-pass spatial filter to remove atmospheric noise on large angular scales, which has the unwelcome side effect of also removing the galaxy’s large-scale structure. We have developed a technique for producing high-resolution submillimeter images of galaxies of large angular size by using the telescope on the ground to determine the small-scale structure (the large Fourier components) and a space telescope (Herschel or Planck) to determine the large-scale structure (the small Fourier components). Using this technique, we are carrying out the HARP and SCUBA-2 High Resolution Terahertz Andromeda Galaxy Survey (HASHTAG), an international Large Program on the James Clerk Maxwell Telescope, with one aim being to produce the first high-fidelity high-resolution submillimeter images of Andromeda. In this paper, we describe the survey, the method we have developed for combining the space-based and ground-based data, and we present the first HASHTAG images of Andromeda at 450 and 850
μ
m. We also have created a method to predict the CO(
J
= 3–2) line flux across M31, which contaminates the 850
μ
m band. We find that while normally the contamination is below our sensitivity limit, it can be significant (up to 28%) in a few of the brightest regions of the 10 kpc ring. We therefore also provide images with the predicted line emission removed.
A
Neisseria gonorrhoeae LightCycler (NGpapLC) assay targeting the
porA pseudogene was compared with bacterial culture for detection of
N. gonorrhoeae in 636 clinical specimens (216 cervical, 185 ...urethral, 196 throat, and 39 rectal swab specimens). The specificity of the NGpapLC assay was further investigated by testing a bacterial reference panel comprising several
Neisseria species. Overall, 19 (3.0%) specimens were positive and 613 (96.4%) specimens were negative by both methods. Four (0.6%) specimens were positive by the NGpapLC assay only. For the cervical and urethral swabs, the NGpapLC provided 100% sensitivity and 100% specificity compared with bacterial culture. Following discrepant analysis, the clinical sensitivity and specificity of the NGpapLC for throat and rectal swabs was also 100%. For the bacterial panel, only
N. gonorrhoeae isolates provided positive results. The results show the NGpapLC assay is suitable for use on a range of clinical specimens and could improve detection of pharyngeal
N. gonorrhoeae.
BACKGROUND: Although the role of vitamin D deficiency in causing osteomalacia is well recognised, there is limited evidence to suggest that vitamin D deficiency is associated with osteoporosis. One ...community based study has suggested a reduction in bone density in females with low vitamin D levels, while another has shown no effect of isolated vitamin D deficiency on population fracture rates. We aimed to assess bone density in a cohort of women with low vitamin D levels but no other identified risk factors for osteoporosis. We wished to see if there was any relationship between the two, in order to clarify whether measurement of vitamin D was justified in aiding selection of patients for DXA, and whether DXA was justified in patients found to have isolated vitamin D deficiency. METHODS: We identified 70 women referred to an open access DXA scanning service by their GP with low vitamin D levels (under 48 nmol/l) as their only risk factor. We performed DXA of hip and spine and recorded the absolute bone density and Z scores for each patient, together with their vitamin D levels. We calculated the mean (SD) values for Z score at hip and spine, and compared these to a control group of women referred for baseline DXA prior to commencing aromatase inhibitors for breast cancer. We also compared the results with those obtained from the rest of the GP database for women referred up with a 10 year risk of osteoporotic fractures calculated at over 10% using FRAX. These statistical comparisons were made using unpaired Students t test. Mean values for Z scores at hip and spine were calculated and compared within the index group for those with vitamin D levels above and below 20 nmol/l using Students t test. Correlation coefficients between vitamin D levels and Z scores at hip and spine were also calculated for the index group. RESULTS: Mean (SD) values for Z scores in the hip and spine for patients with isolated vitamin D deficiency were +0.30 (0.87) and +0.46 (0.92) respectively. These were not significantly different from controls whose corresponding values were +0.17 (0.34) and +0.49 (0.45). By contrast, patients with a 10 year risk of fracture of over 10% had lower values at hip -0.01 (0.07) and spine -0.13 (0.09) p = 0.01. Mean Z scores for those with very low vitamin D levels (under 20 nmol/l) were not significantly different at either site when compared to those with less severe deficiency (20-48 nmol/l) p = 0.26. There was no correlation between vitamin D levels and Z scores at hip or spine r = 0.01 CONCLUSIONS: There was no overall decrease in bone density associated with low vitamin D levels in women in our study. There is no evidence to support the routine measurement of vitamin D to select patients for DXA scanning. There is no reason to perform DXA scans in those patients who have an isolated vitamin D deficiency in the absence of defined risk factors for osteoporosis. Disclosure statement: The authors have declared no conflicts of interest.
We observed the starburst galaxy M82 in 850\(\mu\)m polarised light with the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT). We interpret our observed polarisation geometry as tracing ...a two-component magnetic field: a poloidal component aligned with the galactic 'superwind', extending to a height \(\sim 350\) pc above and below the central bar; and a spiral-arm-aligned, or possibly toroidal, component in the plane of the galaxy, which dominates the 850\(\mu\)m polarised light distribution at galactocentric radii \(\gtrsim 2\) kpc. Comparison of our results with recent HAWC+ measurements of the field in the dust entrained by the M82 superwind suggests that the superwind breaks out from the central starburst at \(\sim 350\) pc above the plane of the galaxy.
We present and analyze observations of polarized dust emission at 850 \(\mu\)m towards the central 1 pc \(\times\) 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with ...SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the BISTRO (B-fields in Star-forming Region Observations) survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well-described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis-Chandrasekhar-Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from \(Herschel\) data and the C\(^{18}\)O (\(J\) = 3-2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 \(\pm\) 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 \(\pm\) 0.02. Additionally, the mean Alfvén Mach number is 0.35 \(\pm\) 0.01. This suggests that in Mon R2, magnetic fields provide resistance against large-scale gravitational collapse, and magnetic pressure exceeds turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically sub-critical.
Observing nearby galaxies with submillimeter telescopes on the ground has two major challenges. First, the brightness is significantly reduced at long submillimeter wavelengths compared to the ...brightness at the peak of the dust emission. Second, it is necessary to use a high-pass spatial filter to remove atmospheric noise on large angular scales, which has the unwelcome by-product of also removing the galaxy's large-scale structure. We have developed a technique for producing high-resolution submillimeter images of galaxies of large angular size by using the telescope on the ground to determine the small-scale structure (the large Fourier components) and a space telescope (Herschel or Planck) to determine the large-scale structure (the small Fourier components). Using this technique, we are carrying out the HARP and SCUBA-2 High Resolution Terahertz Andromeda Galaxy Survey (HASHTAG), an international Large Program on the James Clerk Maxwell Telescope, with one aim being to produce the first high-fidelity high-resolution submillimeter images of Andromeda. In this paper, we describe the survey, the method we have developed for combining the space-based and ground-based data, and present the first HASHTAG images of Andromeda at 450 and 850um. We also have created a method to predict the CO(J=3-2) line flux across M31, which contaminates the 850um band. We find that while normally the contamination is below our sensitivity limit, the contamination can be significant (up to 28%) in a few of the brightest regions of the 10 kpc ring. We therefore also provide images with the predicted line emission removed.
We present the properties of magnetic fields (B-fields) in two clumps (clump 1 and clump 2), located at the waist of the bipolar H II region Sh2-201, based on JCMT SCUBA-2/POL-2 observations of 850 ...\(\mu\)m polarized dust emission. We find that B-fields in the direction of the clumps are bent and compressed, showing bow-like morphologies, which we attribute to the feedback effect of the H II region on the surface of the clumps. Using the modified Davis-Chandrasekhar-Fermi method we estimate B-fields strengths of 266 \(\mu\)G and 65 \(\mu\)G for clump 1 and clump 2, respectively. From virial analyses and critical mass ratio estimates, we argue that clump 1 is gravitationally bound and could be undergoing collapse, whereas clump 2 is unbound and stable. We hypothesize that the interplay between thermal pressure imparted by the H II region, B-field morphologies, and the various internal pressures of the clumps (such as magnetic, turbulent, and gas thermal pressure), has the following consequences: (a) formation of clumps at the waist of the H II region; (b) progressive compression and enhancement of the B-fields in the clumps; (c) stronger B-fields will shield the clumps from erosion by the H II region and cause pressure equilibrium between the clumps and the H II region, thereby allowing expanding I-fronts to blow away from the filament ridge, forming bipolar H II regions; and (d) stronger B-fields and turbulence will be able to stabilize the clumps. A study of a larger sample of bipolar H II regions would help to determine whether our hypotheses are widely applicable.
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