1,829 research outputs found
An eccentrically perturbed Tonks-Girardeau gas
We investigate the static and dynamic properties of a Tonks-Girardeau gas in
a harmonic trap with an eccentric -perturbation of variable strength.
For this we first find the analytic eigensolution of the single particle
problem and use this solution to calculate the spatial density and energy
profiles of the many particle gas as a function of the strength and position of
the perturbation. We find that the crystal nature of the Tonks state is
reflected in both the lowest occupation number and momentum distribution of the
gas. As a novel application of our model, we study the time evolution of the
the spatial density after a sudden removal of the perturbation. The dynamics
exhibits collapses and revivals of the original density distribution which
occur in units of the trap frequency. This is reminiscent of the Talbot effect
from classical optics.Comment: Comments and suggestions are welcom
In-hospital mortality following surgical lung biopsy for interstitial lung disease in the USA: 2000-2011
Rationale: Surgical lung biopsy can help to determine a specific diagnosis in interstitial lung disease, but has associated risks. Most currently available mortality data are derived from case series and may not be generalizable to broader populations.
Objectives: We aimed to assess in-hospital mortality following surgical lung biopsy for interstitial lung disease in a national secondary care dataset from the United States.
Methods: Data were obtained from the 2000-2011 Nationwide Inpatient Sample. Cases were identified using International Classification of Diseases (ICD-9-CM) codes for interstitial lung disease and surgical lung biopsies. Lung resections and cases of lung cancer were excluded. Weighted data were used to estimate numbers of biopsies nationwide and in-hospital mortality, and multivariable logistic regression was used to adjust for sex, age, geographic region, co-morbidity, type of operation and provisional diagnosis.
Measurements and Main Results: We estimated there to be around 12,000 surgical lung biopsies performed annually for interstitial lung disease in the United States, two-thirds of which were performed electively. In-hospital mortality was 1.7% for elective procedures, but significantly higher for non-elective procedures (16.0%). Male sex, increasing age, increasing co-morbidity, open surgery and a provisional diagnosis of idiopathic pulmonary fibrosis or connective tissue disease related interstitial lung disease were risk factors for increased mortality.
Conclusions: In-hospital mortality following elective surgical lung biopsy for interstitial lung disease is just under 2%, but significantly higher for non-elective procedures. Identified risk factors for death should be taken into account when counselling patients on whether to pursue a histological diagnosis
Global incidence and mortality of idiopathic pulmonary fibrosis: a systematic review
Introduction: As idiopathic pulmonary fibrosis emerges as an important public health problem, there is a need to coordinate data on incidence and mortality globally. This study aims to systematically assess all available studies to investigate the global burden of disease.
Methods: Medline and Embase databases were searched systematically for all population-based studies of incidence or mortality of idiopathic pulmonary fibrosis. Clinical case series and prevalence studies were excluded. The search was supplemented using Google search engine, hand-searching of references and conference abstracts. Data were extracted independently by two authors using a pre-specified proforma, with assessment of methodological quality.
Results: 34 studies were identified providing data from 21 countries from 1968-2012. 28 studies reported incidence data, and eight reported mortality data. In studies from year 2000 onwards, we estimated a conservative incidence range of 3-9 cases per 100,000 per year for Europe and North America. Incidence was lower in East Asia and South America. The majority of studies showed an increase in incidence over time.
Conclusions: The incidence of idiopathic pulmonary fibrosis is increasing worldwide, and rates are coming together across countries. Current data suggest incidence is similar to that of conditions such as stomach, liver, testicular and cervical cancers
Complications and mortality in hereditary hemorrhagic telangiectasia: a population-based study
OBJECTIVES:
Studies report that the risks of significant neurologic complications (including stroke, cerebral abscess, and migraine) and hemorrhagic sequelae are high in patients with hereditary hemorrhagic telangiectasia (HHT), and that life expectancy in this cohort is reduced. However, most published cohorts derive from specialist centers, which may be susceptible to bias.
METHODS:
We used a population-based approach to estimate the risks of developing neurologic and hemorrhagic complications of HHT, the association of a diagnosis of HHT with common cardiovascular and malignant comorbidities, and also long-term survival of those with the disease.
RESULTS:
From a UK primary care database of 3.5 million patients (The Health Improvement Network), we identified 675 cases with a diagnosis of HHT and compared them with 6,696 controls matched by age, sex, and primary care practice. Risks of stroke (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.2-2.6), cerebral abscess (OR 30.0, CI 3.1-288), and migraine (OR 1.7, CI 1.3-2.2) were elevated over controls. Bleeding complications including epistaxis (OR 11.6, CI 9.1-14.7) and gastrointestinal hemorrhage (OR 6.1, CI 2.8-13.4) were more common in cases with HHT. Survival of cases with HHT was poorer than controls with a hazard ratio for death of 2.0 (CI 1.6-2.6) and a median age at death 3 years younger.
CONCLUSIONS:
Patients with HHT are at substantially increased risk of serious neurologic and hemorrhagic complications of the disease. Because a diagnosis of HHT is associated with a significantly poorer survival compared with those who have no disease, evaluation of new strategies to improve clinical management is required
On the generalized Davenport constant and the Noether number
Known results on the generalized Davenport constant related to zero-sum
sequences over a finite abelian group are extended to the generalized Noether
number related to the rings of polynomial invariants of an arbitrary finite
group. An improved general upper bound is given on the degrees of polynomial
invariants of a non-cyclic finite group which cut out the zero vector.Comment: 14 page
The VLT-MUSE and ALMA view of the MACS 1931.8-2635 brightest cluster galaxy
We reveal the importance of ongoing in-situ star formation in the Brightest
Cluster Galaxy in the massive cool-core CLASH cluster MACS 1931.8-2635 at
z=0.35. Using a multi-wavelength approach, we assess the stellar and warm
ionized medium components, spatially resolved by the VLT-MUSE spectroscopy, and
link them to the molecular gas by incorporating sub-mm ALMA observations. We
measure the fluxes of strong emission lines, allowing us to determine the
physical conditions of the warm ionized gas. The ionized gas flux brightness
peak corresponds to the location of the supermassive black hole and the system
shows a diffuse warm ionized gas tail extending 30 kpc in N-E direction. The
ionized and molecular gas are co-spatial and co-moving, with the gaseous
component in the tail falling inward, providing fuel for star formation and
accretion-powered nuclear activity. The gas is ionized by a mix of star
formation and other energetic processes which give rise to LINER-like emission,
with active galactic nuclei emission dominant only in the BCG core. We measure
a star formation rate of 97 Msun/yr, with its peak at the BCG core. However,
star formation accounts for only 50-60% of the energetics needed to ionize the
warm gas. In situ star formation generated by thermally unstable intracluster
medium cooling and/or dry mergers dominate the stellar mass growth at z<0.5 and
these mechanisms account for the build-up of 20% of the mass of the system. Our
measurements reveal that the most central regions of the BCG contain the lowest
gas phase oxygen abundance, whereas the tail exhibits slightly more elevated
values. The galaxy is a dispersion dominated system, typical for massive,
elliptical galaxies. The gas and stellar kinematics are decoupled, with the
gaseous velocity fields being more closely related to the bulk motions of the
intracluster medium.Comment: Accepted for publication in A&A on 26.01.2021; Abstract abridged for
arXiv; 31 pages, 20 figure
Rate of improvement of CF life expectancy exceeds that of general population: observational death registration study
Background: It is unclear why cystic fibrosis (CF) survival has improved. We wished to quantify increases in CF median age of death in the context of general population survival improvement.
Method: Death registration data analysis (US, England & Wales (E&W)—1972–2009).
Results: CF median age of death is higher in US than E&W and greater for males, opposite to that of death from all causes. CF median age of death has increased by 0.543 life years per year (E&W, US combined (95% confidence interval 0.506, 0.582)). The difference in median age at death between those dying from all causes and CF decreased in both territories. CF median age of death for males is greater than for females in both territories. This gap has not narrowed.
Conclusion: The median age of death of people with CF is improving more rapidly than that of the general population in US and E&W
Surgical lung biopsy for the diagnosis of interstitial lung disease in England: 1997-2008
Introduction: International guidelines and new targeted therapies for idiopathic pulmonary fibrosis have increased the need for accurate diagnosis of interstitial lung disease, which may lead to more surgical lung biopsies. This study aims to assess the risk of this procedure in patients from the United Kingdom.
Methods: We used Hospital Episodes Statistics data from 1997-2008 to assess the frequency of surgical lung biopsy for interstitial lung disease in England. We identified cardiothoracic surgical patients using ICD-10 codes for interstitial lung disease and OPCS-4 codes for surgical lung biopsy. We excluded those with lung resections or lung cancer. We estimated in-hospital, 30-day and 90-day mortality following the procedure, and linked to cause of death using data from the Office of National Statistics.
Results: We identified 2,820 patients with interstitial lung disease undergoing surgical lung biopsy during the 12 year period. The number of biopsies increased over the time period studied. In-hospital, 30-day and 90-day mortality were 1.7%, 2.4% and 3.9% respectively. Male sex, increasing age, increasing co-morbidity and open surgery were risk factors for mortality.
Discussion: Surgical lung biopsy for interstitial lung disease has a similar mortality to lobectomy for lung cancer, and clinicians and patients should understand the likely risks involved
Complex diffuse radio emission in the merging PLANCK ESZ cluster Abell 3411
We present VLA radio and Chandra X-ray observations of the merging galaxy
cluster Abell 3411. For the cluster, we find an overall temperature of 6.4 keV
and an X-ray luminosity of 2.8 x 10^{44} erg s^{-1} between 0.5 and 2.0 keV.
The Chandra observation reveals the cluster to be undergoing a merger event.
The VLA observations show the presence of large-scale diffuse emission in the
central region of the cluster, which we classify as a 0.9 Mpc size radio halo.
In addition, a complex region of diffuse, polarized emission is found in the
southeastern outskirts of the cluster, along the projected merger axis of the
system. We classify this region of diffuse emission as a radio relic. The total
extent of this radio relic is 1.9 Mpc. For the combined emission in the cluster
region, we find a radio spectral index of -1.0 \pm 0.1 between 74 MHz and 1.4
GHz. The morphology of the radio relic is peculiar, as the relic is broken up
into five fragments. This suggests that the shock responsible for the relic has
been broken up due to interaction with a large-scale galaxy filament connected
to the cluster or other substructures in the ICM. Alternatively, the complex
morphology reflects the presence of electrons in fossil radio bubbles that are
re-accelerated by a shock.Comment: Accepted for publication in ApJ, 8 pages, 5 figure
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