185 research outputs found
Changes in the trajectory of the radio jet in 0735+178?
We present multi-epoch 8.4 and 43 GHz Very Long Baseline Array images of the
BL Lac object 0735+178. The images confirm the presence of a twisted jet with
two sharp apparent bends of 90 within two milliarcseconds of the
core, resembling a helix in projection. The observed twisted geometry could be
the result of precession of the jet inlet, but is more likely produced by
pressure gradients in the external medium through which the jet propagates.
Quasi-stationary components are observed at the locations of the 90
bends, possibly produced by differential Doppler boosting. Identification of
components across epochs, since the earliest VLBI observations of this source
in 1979.2, proves difficult due to the sometimes large time gaps between
observations. One possible identification suggests the existence of
superluminal components following non--ballistic trajectories with velocities
up to . However, in images obtained after mid-1995,
components show a remarkable tendency to cluster near several jet positions,
suggesting a different scenario in which components have remained nearly
stationary in time at least since mid-1995. Comparison with the earlier
published data, covering more than 19 years of observations, suggests a
striking qualitative change in the jet trajectory sometime between mid-1992 and
mid-1995, with the twisted jet structure with stationary components becoming
apparent only at the later epochs. This would require a re-evaluation of the
physical parameters estimated for 0735+178, such as the observing viewing
angle, the plasma bulk Lorentz factor, and those deduced from these.Comment: 18 pages, 5 figures, accepted for publication in MNRA
Autoimmune and viral risk factors are associated with achalasia: A case-control study
Background: Achalasia is a rare esophageal motility disorder of uncertain etiology. While past studies have indicated that autoimmune conditions and viral infections may be associated with development of achalasia, these associations are yet to be examined in large, population-based studies. Methods: A matched case-control study was performed using administrative claim data from the IBM MarketScan Commercial Claims and Encounters Database between 2000 and 2019. A history of selected autoimmune conditions and viral infections was assessed using past medical claims. Multivariable conditional logistic regression was used to account for the matched nature of the study design and further control for confounding by demographic and clinical characteristics when reporting adjusted odds ratios (aORs). Key Results: Among 6769 cases and 27,076 controls, presence of any of the autoimmune conditions studied was associated with increased odds of achalasia (aOR = 1.26, 95% CI: 1.11, 1.42). Scleroderma or systemic sclerosis (aOR = 8.13, 95% CI: 3.34, 19.80) and Addison's disease (aOR = 3.83, 95% CI: 1.83, 8.04) had the strongest associations with achalasia. Presence of any of the viral infections studied was also associated with an increased risk of achalasia (aOR = 1.58, 95% CI: 1.23, 2.01). Varicella zoster virus (aOR = 3.84, 95% CI: 1.94, 7.62) and human papillomavirus (aOR = 1.77, 95% CI: 1.15, 2.73) both had strong relationships with achalasia. Conclusions and Inferences: These findings suggest that achalasia may have autoimmune and viral components contributing to its etiology. Future mechanistic studies could target specific diseases and agents highlighted by this research
Epidemiologic and Economic Burden of Achalasia in the United States
Background & Aims: Achalasia is a debilitating chronic condition of the esophagus. Currently there are no national estimates on the epidemiologic and economic burden of disease. We sought to estimate trends in incidence and prevalence of achalasia by age-sex strata, and to estimate the total direct medical costs attributed to achalasia in the United States. Methods: We conducted a cohort study using two administrative claims databases: IBM MarketScan Commercial Claims and Encounters database (2001-2018; age <65) and a 20% sample of nationwide Medicare enrollment and claims (2007-2015; age ≥65). Point prevalence was calculated on the first day of each calendar year; the incidence rate captured new cases developed in the ensuing year. Utilization rates of healthcare services and procedures were reported. Mean costs per patient were calculated and standardized to the corresponding U.S. Census Bureau population data to derive achalasia-specific total direct medical costs. Results: The crude prevalence of achalasia per 100,000 persons was 18.0 (95% CI, 17.4, 18.7) in MarketScan and 162.1 (95% CI, 157.6, 166.6) in Medicare. The crude incidence rate per 100,000 person-years was 10.5 (95% CI, 9.9, 11.1) in MarketScan and 26.0 (95% CI, 24.9, 27.2) in Medicare. Incidence and prevalence increased substantially over time in the Medicare cohort, and increased with more advanced age in both cohorts. Utilization of achalasia-specific healthcare was high; national estimates of total direct medical costs exceeded $408 million in 2018. Conclusions: Achalasia has a higher epidemiologic and economic burden in the US than previously suggested, with diagnosis particularly increasing in older patients
Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2
We have searched for the proton decay mode proton to neutrino K+ using the
one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained
from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for
occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0.
We found one candidate event consistent with background, yielding a limit,
tau/B > 4.3 10^{31} years at 90% CL with no background subtraction.Comment: 13 pages, Latex, 3 tables and 3 figures, Accepted by Physics Letters
Whole-genome sequencing of Schistosoma mansoni reveals extensive diversity with limited selection despite mass drug administration
Control and elimination of the parasitic disease schistosomiasis relies on mass administration of praziquantel. Whilst these programmes reduce infection prevalence and intensity, their impact on parasite transmission and evolution is poorly understood. Here we examine the genomic impact of repeated mass drug administration on Schistosoma mansoni populations with documented reduced praziquantel efficacy. We sequenced whole-genomes of 198 S. mansoni larvae from 34 Ugandan children from regions with contrasting praziquantel exposure. Parasites infecting children from Lake Victoria, a transmission hotspot, form a diverse panmictic population. A single round of treatment did not reduce this diversity with no apparent population contraction caused by long-term praziquantel use. We find evidence of positive selection acting on members of gene families previously implicated in praziquantel action, but detect no high frequency functionally impactful variants. As efforts to eliminate schistosomiasis intensify, our study provides a foundation for genomic surveillance of this major human parasite
Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays
Average charged multiplicities have been measured separately in , and
light quark () events from decays measured in the SLD experiment.
Impact parameters of charged tracks were used to select enriched samples of
and light quark events, and reconstructed charmed mesons were used to select
quark events. We measured the charged multiplicities:
,
, from
which we derived the differences between the total average charged
multiplicities of or quark events and light quark events: and . We compared
these measurements with those at lower center-of-mass energies and with
perturbative QCD predictions. These combined results are in agreement with the
QCD expectations and disfavor the hypothesis of flavor-independent
fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters
Rhenium and yttrium ions as antimicrobial agents against multidrug resistant Klebsiella pneumoniae and Acinetobacter baumannii biofilms
© 2019 The Authors. Letters in Applied Microbiology published by John Wiley & Sons Ltd on behalf of Society for Applied Microbiology. Antimicrobial resistance presents major global concerns to patient health. In this study, metal ions of molybdenum, rhenium, yttrium and thallium were tested against bacteria in planktonic and biofilm form using one strain of Klebsiella pneumoniae and Acinetobacter baumannii. The antimicrobial efficacy of the metal ions was evaluated against the planktonic bacterial strains using minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations, whilst the efficacy of the metal ions against biofilms was tested using a crystal violet biofilm assay. Live Dead staining was used to visualize the antimicrobial activity elicited by the metal ions on the bacterial cell. The results showed that higher concentrations of the metals were required to inhibit the growth of biofilms (72·9 mg l −1 to 416·7 mg l −1 ), in comparison to their planktonic counterparts. MICs of the metal ions (<46·9 mg l −1 ) (planktonic cells) did not affect biofilm formation. Overall, rhenium and yttrium were effective antimicrobial agents. Molybdenum demonstrated the greatest level of biotoxicity. When taking into account these results and the known toxicity of thallium, it is possible that rhenium or yttrium ions could be developed as effective biocidal formulations in order to prevent transmission in healthcare environments. Significance and Impact of the Study: The metal ions, molybdenum, rhenium, thallium and yttrium were tested against both Klebsiella pneumoniae and Acinetobacter baumannii in planktonic and biofilm forms. This research demonstrated that all the metal ions may be effective antimicrobial agents. However, molybdenum induced high levels of cytotoxicity, whilst, there was no significant difference in the toxicity of the other metal ions tested. When considering the results for the antimicrobial efficacy and biotoxicity of the metal ions, in conjunction with the known toxicity of thallium in certain chemical compositions, it was concluded that overall rhenium or yttrium ions may be effective antimicrobial agents, one potential application may be utilizing these metal ions in hospital surface cleaning formulations
AD51B in Familial Breast Cancer
Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients and subsequently genotyped the mutation in additional breast cancer cases (n = 5259) and population controls (n = 3586) from Finland and Belarus. No significant association with breast cancer risk was seen in the meta-analysis of the Finnish datasets or in the large BCAC dataset. The association with previously identified risk variants rs999737, rs2588809, and rs1314913 was replicated among all breast cancer cases and also among familial cases in the BCAC dataset. The most significant association was observed for the haplotype carrying the risk-alleles of all the three SNPs both among all cases (odds ratio (OR): 1.15, 95% confidence interval (CI): 1.11–1.19, P = 8.88 x 10−16) and among familial cases (OR: 1.24, 95% CI: 1.16–1.32, P = 6.19 x 10−11), compared to the haplotype with the respective protective alleles. Our results suggest that loss-of-function mutations in RAD51B are rare, but common variation at the RAD51B region is significantly associated with familial breast cancer risk
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