301 research outputs found
The Molecular Gas Reservoirs of Galaxies: A comparison of CO(1-0) and dust-based molecular gas masses
We test the use of long-wavelength dust continuum emission as a molecular gas
tracer at high redshift, via a unique sample of 12, z~2 galaxies with
observations of both the dust continuum and CO(1-0) line emission (obtained
with the Atacama Large Millimeter Array and Karl G. Jansky Very Large Array,
respectively). Our work is motivated by recent, high redshift studies that
measure molecular gas masses (\ensuremath{\rm{M}_{\rm{mol}}}) via a calibration
of the rest-frame m luminosity () against the
CO(1-0)-derived \ensuremath{\rm{M}_{\rm{mol}}}\ of star-forming galaxies. We
hereby test whether this method is valid for the types of high-redshift,
star-forming galaxies to which it has been applied. We recover a clear
correlation between the rest-frame m luminosity, inferred from the
single-band, long-wavelength flux, and the CO(1-0) line luminosity, consistent
with the samples used to perform the m calibration. The molecular gas
masses, derived from , agree to within a factor of
two with those derived from CO(1-0). We show that this factor of two
uncertainty can arise from the values of the dust emissivity index and
temperature that need to be assumed in order to extrapolate from the observed
frequency to the rest-frame at 850. The extrapolation to
850 therefore has a smaller effect on the accuracy of \Mmol\
derived via single-band dust-continuum observations than the assumed
CO(1-0)-to-\ensuremath{\rm{M}_{\rm{mol}}}\ conversion factor. We therefore
conclude that single-band observations of long-wavelength dust emission can be
used to reliably constrain the molecular gas masses of massive, star-forming
galaxies at
Prognostic utility of human complement factor H related protein test (the BTA stat® Test)
The purpose of the study was to determine, in addition to well-known prognostic factors, histological grade, stage, tumour size and multiplicity, the correlation of BTA stat Test on disease free interval (DFI) on primary superficial bladder cancer. A total of 116 patients with newly diagnosed bladder cancer were evaluated in a prospective multicentre study. A voided urine sample was obtained prior to TURB and split for culture, cytology and BTA stat testing. Follow-up data for the patients were collected until the first recurrence or the last visit and the DFI was analysed by Kaplan–Meier method and Cox analysis. Ninety-seven of the 116 (83.6%) patients were eligible for analysis. The BTA stat Test was positive in 73 (75.3%) patients, whereas cytology detected 20 (20.6%) cases. The DFI was found to be shorter among patients with a positive BTA stat Test, and also among those with intermediate or high-grade tumours. The BTA stat Test result divided patients with grade 2 tumours into two prognostic groups, in that those testing positive had 68.6% risk of recurrence during the first year compared to 42.9% risk of those with a negative test result (P = 0.041). Although the effect of tumour size on DFI was notable, the difference did not reach statistical significance (P = 0.064). Number of tumours was not related to DFI, nor was the difference between different stage of tumour of significance. BTA stat Test is not only sensitive in detection of primary bladder cancer, but also might have some independent prognostic significance. © 2001 Cancer Research Campaign http://www.bjcancer.co
Visual versus automated analysis of [I-123]FP-CIT SPECT scans in parkinsonism
The clinical evaluation of dopamine transporter (DAT) SPECT scans typically relies on visual analysis in combination with an automated semi-quantitative method. The interpretation of the results may be difficult in cases that show disagreement between the two methods on the borderline of abnormality. The frequency and clinical characteristics of such cases are unclear. Automated semi-quantitative analyses and independent visual analyses by two experienced nuclear medicine physicians and four inexperienced raters were performed for 120 patients with clinically uncertain parkinsonism scanned with brain [I-123]FP-CIT SPECT. Agreement was evaluated with kappa statistics. The clinical characteristics of patients who had discrepant findings between the two analysis methods were investigated. The expert raters outperformed nonexperts in terms of agreement between visual and automated analyses (kappa = 0.66, 0.72 vs. 0.23-0.54) and between raters (kappa = 0.81 vs. 0.44-0.63). Twelve patients showed discrepant findings between the visual and automated analyses. These patients were older compared to other patients (p = 0.023), had 17.6 % lower mean striatal tracer binding compared to normal scans (p = 0.003) and 62.7 % higher compared to abnormal scans (p < 0.001). After a minimum of 4.5 years of clinical follow-up, none of these patients developed neurodegenerative parkinsonism. Clinical DAT SPECT scans show discrepancies between visual and automated analyses in 10 % of cases. The patients with discrepant findings are older, show normal to slightly abnormal tracer binding, and importantly, do not develop neurodegenerative parkinsonism syndromes. Visual analyses by experienced raters are reliable, but the diagnostic accuracy in discrepant cases can be improved by an automated method
Reappearance of Symptoms after GPi-DBS Discontinuation in Cervical Dystonia
Background: Deep brain stimulation of the globus pallidus interna (GPi-DBS) is a highly efficacious treatment for cervical dystonia. Typically, the treatment response is delayed, appearing and increasing even months after implantation. However, it is not known how fast the symptoms reappear and whether there is a long-term therapeutic effect after the stimulation is discontinued.Objectives: To study symptom reappearance after switching GPi-DBS off in cervical dystonia.Methods: Twelve patients with bilateral GPi-DBS were included in the study. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) was evaluated during the study with DBS stimulation on, after switching the stimulation off and 2 days after the stimulation was switched off. Presurgical symptom severity and best postsurgical response were extracted from the hospital records.Results: At the time of the investigation, GPi-DBS was associated with 67 (SD 39)% symptom improvement of presurgical symptoms severity (P = 0.001). Symptom improvement decreased to 27 (53)% (P = 0.046) (n = 12) acutely after switching the stimulation off and was further reduced to 4 (56)% 2 days after discontinuation (P = 0.01) (n = 11), reaching the presurgical level (P = 0.42). In descriptive analyses, older age was associated with faster worsening of symptoms (P < 0.05). Presurgical symptoms severity, stimulation parameters or magnitude of treatment response did not predict symptom worsening. All but one patient tolerated 2 days DBS switched off.Conclusions: The results provide novel information about the time frame and severity of symptom worsening after discontinuing GPi-DBS in cervical dystonia. Symptoms partially reappear immediately after discontinuing GPi-DBS and full presurgical symptom severity is reached within 2 days
Obscuration beyond the nucleus: infrared quasars can be buried in extreme compact starbursts
In the standard quasar model, the accretion disk obscuration is due to the
canonical dusty torus. Here, we argue that a substantial part of the quasar
obscuration can come from the interstellar medium (ISM) when the quasars are
embedded in compact starbursts. We use an obscuration-unbiased sample of 578
infrared (IR) quasars at and archival ALMA submillimeter host
galaxy sizes to investigate the ISM contribution to the quasar obscuration. We
calculate SFR and ISM column densities for the IR quasars and a control sample
of submillimeter galaxies (SMGs) not hosting quasar activity and show that: (1)
the quasar obscured fraction is constant up to , and then increases towards higher SFR, suggesting that the ISM
obscuration plays a significant role in starburst host galaxies, and (2) at
, the SMGs and IR quasars have
similarly compact submillimeter sizes () and,
consequently, the ISM can heavily obscure the quasar, even reaching
Compton-thick () levels in extreme cases.
Based on our results, we infer that of the IR quasars with
are obscured solely by the ISM.Comment: Accepted for publication in MNRAS Letter
Fecal microbiome alterations in treatment-naive de novo Parkinson's disease
Gut microbiota alterations in Parkinson's disease (PD) have been found in several studies and are suggested to contribute to the pathogenesis of PD. However, previous results could not be adequately adjusted for a potential confounding effect of PD medication and disease duration, as almost all PD participants were already using dopaminergic medication and were included several years after diagnosis. Here, the gut microbiome composition of treatment-naive de novo PD subjects was assessed compared to healthy controls (HC) in two large independent case-control cohorts (n = 136 and 56 PD, n = 85 and 87 HC), using 16S-sequencing of fecal samples. Relevant variables such as technical batches, diet and constipation were assessed for their potential effects. Overall gut microbiome composition differed between PD and HC in both cohorts, suggesting gut microbiome alterations are already present in de novo PD subjects at the time of diagnosis, without the possible confounding effect of dopaminergic medication. Although no differentially abundant taxon could be replicated in both cohorts, multiple short chain fatty acids (SCFA) producing taxa were decreased in PD in both cohorts. In particular, several taxa belonging to the family Lachnospiraceae were decreased in abundance. Fewer taxonomic differences were found compared to previous studies, indicating smaller effect sizes in de novo PD.Peer reviewe
Molecular Gas Reservoirs of z ∼ 2 Galaxies: A Comparison of CO(1−0) and Dust-based Molecular Gas Masses
We test the use of long-wavelength dust continuum emission as a molecular gas tracer at high redshift, via a unique sample of a dozen z ~ 2 galaxies with observations of both the dust continuum and CO(1−0) line emission (obtained with the Atacama Large Millimeter Array and Karl G. Jansky Very Large Array, respectively). Our work is motivated by recent high-redshift studies that measure molecular gas masses (M_(mol)) via a calibration of the rest-frame 850 μm luminosity (L_(850 μm,rest)) against the CO(1−0)-derived M_(mol) of star-forming galaxies. We therefore test whether this method is valid for the types of high-redshift, star-forming galaxies to which it has been applied. We recover a clear correlation between the rest-frame 850 μm luminosity, inferred from the single-band, long-wavelength flux, and the CO(1−0) line luminosity, consistent with the samples used to perform the 850 μm calibration. The molecular gas masses, derived from L_(850 μm,rest), agree to within a factor of two with those derived from CO(1−0). We show that this factor of two uncertainty can arise from the values of the dust emissivity index and temperature that need to be assumed in order to extrapolate from the observed frequency to the rest-frame at 850 μm. The extrapolation to 850 μm therefore has a smaller effect on the accuracy of M_(mol) derived via single-band dust-continuum observations than the assumed CO(1−0)-to- M_(mol) conversion factor. We therefore conclude that single-band observations of long-wavelength dust emission can be used to reliably constrain the molecular gas masses of massive, star-forming galaxies at z ≳ 2
A Significant Excess in Major Merger Rate for AGNs with the Highest Eddington Ratios at z \u3c 0.2
Observational studies are increasingly finding evidence against major mergers being the dominant mechanism responsible for triggering an active galactic nucleus (AGN). After studying the connection between major mergers and AGNs with the highest Eddington ratios at z = 2, we here expand our analysis to z \u3c 0.2, exploring the same AGN parameter space. Using ESO VLT/FORS2 B-, V-, and color images, we examine the morphologies of 17 galaxies hosting AGNs with Eddington ratios , and 25 mass- and redshift-matched control galaxies. To match the appearance of the two samples, we add synthetic point sources to the inactive comparison galaxies. The combined sample of AGN and inactive galaxies was independently ranked by 19 experts with respect to the degree of morphological distortion. We combine the resulting individual rankings into multiple overall rankings, from which we derive the respective major merger fractions of the two samples. With a best estimate of fm,agn = 0.41 ± 0.12 for the AGN host galaxies and fm,ina = 0.08 ± 0.06 for the inactive galaxies, our results imply that our AGN host galaxies have a significantly higher merger rate, regardless of the observed wavelength or applied methodology. We conclude that although major mergers are an essential mechanism to trigger local high Eddington ratio AGNs at z \u3c 0.2, the origin of of this specific AGN subpopulation still remains unclear
Symptoms and diagnostic delays in bladder cancer with high risk of recurrence: results from a prospective FinnBladder 9 trial
Purpose: To investigate the symptoms and delays in the clinical pathway of bladder cancer (BC).Methods: This is a substudy of a prospective, randomized, multicenter phase III study (FinnBladder 9, NCT01675219) where the efficacy of photodynamic diagnosis and 6 weekly optimized mitomycin C instillations are studied in pTa bladder cancer with high risk for recurrence. The data of presenting symptoms and critical time points were prospectively collected, and the effect of factors on delays was analyzed.Results: At the time of analysis, 245 patients were randomized. Analysis included 131 patients with primary bladder cancer and their complete data. Sixty-nine percent had smoking history and 67% presented with macroscopic hematuria. Median patient delay (from symptoms to health-care contact) was 7 days. The median general practice delay (from health-care contact to urology referral) was 8 days. Median time from urology referral to cystoscopy was 23 days and from cystoscopy to TUR-BT 21 days. Total time used in the clinical pathway (from symptom to TUR-BT) was 78 days. Current and former smokers had non-significantly shorter patient-related and general practice delays compared to never smokers. TUR-BT delay was significantly shorter in patients with malignant cytology (16 days) compared to patients with benign cytology (21 days, p = 0.03).Conclusions: Patient-derived delay was short and most of the delay occurred in the referral centers. The majority had macroscopic hematuria as the initial symptom. Surprisingly, current and past smokers were more prone to contact the health-care system compared to never smokers.</p
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