The almost ubiquitous association of 6.7-GHz methanol masers with dust

We report the results of 870-μm continuum observations, using the Large APEX Bolometer Camera, towards 77 class-II, 6.7-GHz methanol masers identified by the Methanol MultiBeam (MMB) survey to map the thermal emission from cool dust towards these objects. These data complement a study of 630 methanol masers associated with compact dense clumps identified from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) survey. Compact dust emission is detected towards 70 sources, which implies a dust-association rate of 99 per cent for the full MMB catalogue. Evaluation of the derived dust and maser properties leads us to conclude that the combined sample represents a single population tracing the same phenomenon. We find median clump masses of a few 103 M⊙ and that all but a handful of sources satisfy the mass–size criterion required for massive star formation. This study provides the strongest evidence of the almost ubiquitous association of methanol masers with massive, star-forming clumps. The fraction of methanol-maser associated clumps is a factor of ∼2 lower in the outer Galaxy than the inner Galaxy, possibly a result of the lower metallicity environment of the former. We find no difference in the clump-mass and maser-luminosity distributions of the inner and outer Galaxy. The maser-pumping and clump formation mechanisms are therefore likely to be relatively invariant to Galactic location. Finally, we use the ratio of maser luminosity and clump mass to investigate the hypothesis that the maser luminosity is a good indicator of the evolutionary stage of the embedded source, however, we find no evidence to support this

ATLASGAL - environments of 6.7 GHz methanol masers

Using the 870 μm APEX Telescope large area survey of the Galaxy, we have identified 577 submillimetre continuum sources with masers from the methanol multibeam survey in the region 280° 20 M. Furthermore, almost all clumps satisfy the empirical mass-size criterion for massive star formation. Bolometric luminosities taken from the literature for ∼100 clumps range between ∼100 and 10 L. This confirms the link between methanol masers and massive young stars for 90 per cent of our sample. The Galactic distribution of sources suggests that the star formation efficiency is significantly reduced in the Galactic Centre region, compared to the rest of the survey area, where it is broadly constant, and shows a significant drop in the massive star formation rate density in the outer Galaxy. We find no enhancement in source counts towards the southern Scutum-Centaurus arm tangent at ℓ ∼ 315°, which suggests that this arm is not actively forming stars. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society

ATLASGAL - physical parameters of dust clumps associated with 6.7 GHz methanol masers

We have constructed the largest sample of dust-associated class II 6.7 GHz methanol masers yet obtained. New measurements from the Methanol Multibeam (MMB) survey were combined with the 870 μm APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) and the 850 μm JCMT Plane Survey (JPS). Together with two previous studies we have now identified the host clumps for 958 methanol masers across the Galactic Plane, covering approximately 99 per cent of the MMB catalogue and increasing the known sample of dust-associated masers by over 30 per cent. We investigate correlations between the physical properties of the clumps and masers using distances and luminosities drawn from the literature. Clumps hosting methanol masers are significantly more compact and have higher volume densities than the general population of clumps. We determine a minimum volume density threshold of n(H2) ≥ 104 cm−3 for the efficient formation of intermediate- and high-mass stars. We find 6.7 GHz methanol masers are associated with a distinct part of the evolutionary process (Lbol/Mfwhm ratios of between 100.6 and 102.2) and have well-defined turning on and termination points. We estimate the lower limit for the mass of embedded objects to be ≥6 M⊙ and the statistical lifetime of the methanol maser stage to be ∼3.3 × 104 yr. This suggests that methanol masers are indeed reliable tracers of high-mass star formation, and indicates that the evolutionary period traced by this marker is relatively rapid

ATLASGAL - towards a complete sample of massive star forming clumps

By matching infrared-selected, massive young stellar objects (MYSOs) and compact HII regions in the Red MSX Source survey to massive clumps found in the submillimetre ATLASGAL (APEX Telescope Large Area Survey of the Galaxy) survey, we have identified ~1000 embedded young massive stars between 280 {ring operator} < l < 350 {ring operator} and 10 {ring operator} < l < 60 {ring operator} with | b | < 1 {ring operator} . 5. Combined with an existing sample of radio-selected methanol masers and compact HII regions, the result is a catalogue of ~1700 massive stars embedded within ~1300 clumps located across the inner Galaxy, containing three observationally distinct subsamples, methanol-maser, MYSO and HII-region associations, covering the most important tracers of massive star formation, thought to represent key stages of evolution. We find that massive star formation is strongly correlated with the regions of highest column density in spherical, centrally condensed clumps. We find no significant differences between the three samples in clump structure or the relative location of the embedded stars, which suggests that the structure of a clump is set before the onset of star formation, and changes little as the embedded object evolves towards the main sequence. There is a strong linear correlation between clump mass and bolometric luminosity, with the most massive stars forming in the most massive clumps. We find that the MYSO and HII-region subsamples are likely to cover a similar range of evolutionary stages and that the majority are near the end of their main accretion phase. We find few infrared-bright MYSOs associated with the most massive clumps, probably due to very short pre-main-sequence lifetimes in the most luminous sources. © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society

Religiosity and decreased risk of substance use disorders: is the effect mediated by social support or mental health status?

The negative association between religiosity (religious beliefs and church attendance) and the likelihood of substance use disorders is well established, but the mechanism(s) remain poorly understood. We investigated whether this association was mediated by social support or mental health status. We utilized cross-sectional data from the 2002 National Survey on Drug Use and Health (n = 36,370). We first used logistic regression to regress any alcohol use in the past year on sociodemographic and religiosity variables. Then, among individuals who drank in the past year, we regressed past year alcohol abuse/dependence on sociodemographic and religiosity variables. To investigate whether social support mediated the association between religiosity and alcohol use and alcohol abuse/dependence we repeated the above models, adding the social support variables. To the extent that these added predictors modified the magnitude of the effect of the religiosity variables, we interpreted social support as a possible mediator. We also formally tested for mediation using path analysis. We investigated the possible mediating role of mental health status analogously. Parallel sets of analyses were conducted for any drug use, and drug abuse/dependence among those using any drugs as the dependent variables. The addition of social support and mental health status variables to logistic regression models had little effect on the magnitude of the religiosity coefficients in any of the models. While some of the tests of mediation were significant in the path analyses, the results were not always in the expected direction, and the magnitude of the effects was small. The association between religiosity and decreased likelihood of a substance use disorder does not appear to be substantively mediated by either social support or mental health status

Clinical and molecular consequences of exon 78 deletion in DMD gene

We present a 13-year-old patient with persistent increase of serum Creatine Kinase (CK) and myalgia after exertion. Skeletal muscle biopsy showed marked reduction of dystrophin expression leading to genetic analysis of DMD gene by MLPA, which detected a single deletion of exon 78. To the best of our knowledge, DMD exon 78 deletion has never been described in literature and, according to prediction, it should lead to loss of reading frame in the dystrophin gene. To further assess the actual effect of exon 78 deletion, we analysed cDNA from muscle mRNA. This analysis confirmed the absence of 32 bp of exon 78. Exclusion of exon 78 changes the open reading frame of exon 79 and generate a downstream stop codon, producing a dystrophin protein of 3703 amino acids instead of 3685 amino acids. Albeit loss of reading frame usually leads to protein degradation and severe phenotype, in this case, we demonstrated that deletion of DMD exon 78 can be associated with a functional protein able to bind DGC complex and a very mild phenotype. This study adds a novel deletion in DMD gene in human and helps to define the compliance between maintaining/disrupting the reading frame and clinical form of the disease

The influence of the accessory genome on bacterial pathogen evolution

Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens’ frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorise the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution

Noise Reduction and Image Quality Improvement of Low Dose and Ultra Low Dose Brain Perfusion CT by HYPR-LR Processing

To evaluate image quality and signal characteristics of brain perfusion CT (BPCT) obtained by low-dose (LD) and ultra-low-dose (ULD) protocols with and without post-processing by highly constrained back-projection (HYPR)–local reconstruction (LR) technique.Simultaneous BPCTs were acquired in 8 patients on a dual-source-CT by applying LD (80 kV,200 mAs,14×1.2 mm) on tube A and ULD (80 kV,30 mAs,14×1.2 mm) on tube B. Image data from both tubes was reconstructed with identical parameters and post-processed using the HYPR-LR. Correlation coefficients between mean and maximum (MAX) attenuation values within corresponding ROIs, area under attenuation curve (AUC), and signal to noise ratio (SNR) of brain parenchyma were assessed. Subjective image quality was assessed on a 5-point scale by two blinded observers (1:excellent, 5:non-diagnostic).Radiation dose of ULD was more than six times lower compared to LD. SNR was improved by HYPR: ULD vs. ULD+HYPR: 1.9±0.3 vs. 8.4±1.7, LD vs. LD+HYPR: 5.0±0.7 vs. 13.4±2.4 (both p<0.0001). There was a good correlation between the original datasets and the HYPR-LR post-processed datasets: r = 0.848 for ULD and ULD+HYPR and r = 0.933 for LD and LD+HYPR (p<0.0001 for both). The mean values of the HYPR-LR post-processed ULD dataset correlated better with the standard LD dataset (r = 0.672) than unprocessed ULD (r = 0.542), but both correlations were significant (p<0.0001). There was no significant difference in AUC or MAX. Image quality was rated excellent (1.3) in LD+HYPR and non-diagnostic (5.0) in ULD. LD and ULD+HYPR images had moderate image quality (3.3 and 2.7).SNR and image quality of ULD-BPCT can be improved to a level similar to LD-BPCT when using HYPR-LR without distorting attenuation measurements. This can be used to substantially reduce radiation dose. Alternatively, LD images can be improved by HYPR-LR to higher diagnostic quality

Nurse led, primary care based antiretroviral treatment versus hospital care: a controlled prospective study in Swaziland

<p>Abstract</p> <p>Background</p> <p>Antiretroviral treatment services delivered in hospital settings in Africa increasingly lack capacity to meet demand and are difficult to access by patients. We evaluate the effectiveness of nurse led primary care based antiretroviral treatment by comparison with usual hospital care in a typical rural sub Saharan African setting.</p> <p>Methods</p> <p>We undertook a prospective, controlled evaluation of planned service change in Lubombo, Swaziland. Clinically stable adults with a CD4 count > 100 and on antiretroviral treatment for at least four weeks at the district hospital were assigned to either nurse led primary care based antiretroviral treatment care or usual hospital care. Assignment depended on the location of the nearest primary care clinic. The main outcome measures were clinic attendance and patient experience.</p> <p>Results</p> <p>Those receiving primary care based treatment were less likely to miss an appointment compared with those continuing to receive hospital care (RR 0·37, <it>p </it>< 0·0001). Average travel cost was half that of those receiving hospital care (<it>p </it>= 0·001). Those receiving primary care based, nurse led care were more likely to be satisfied in the ability of staff to manage their condition (RR 1·23, <it>p </it>= 0·003). There was no significant difference in loss to follow-up or other health related outcomes in modified intention to treat analysis. Multilevel, multivariable regression identified little inter-cluster variation.</p> <p>Conclusions</p> <p>Clinic attendance and patient experience are better with nurse led primary care based antiretroviral treatment care than with hospital care; health related outcomes appear equally good. This evidence supports efforts of the WHO to scale-up universal access to antiretroviral treatment in sub Saharan Africa.</p

Aneuploidy Detection in Pigs Using Comparative Genomic Hybridization: From the Oocytes to Blastocysts

Data on the frequency of aneuploidy in farm animals are lacking and there is the need for a reliable technique which is capable of detecting all chromosomes simultaneously in a single cell. With the employment of comparative genomic hybridization coupled with the whole genome amplification technique, this study brings new information regarding the aneuploidy of individual chromosomes in pigs. Focus is directed on in vivo porcine blastocysts and late morulas, 4.7% of which were found to carry chromosomal abnormality. Further, ploidy abnormalities were examined using FISH in a sample of porcine embryos. True polyploidy was relatively rare (1.6%), whilst mixoploidy was presented in 46.8% of embryos, however it was restricted to only a small number of cells per embryo. The combined data indicates that aneuploidy is not a prevalent cause of embryo mortality in pigs