2,210 research outputs found
Superfluidity versus localization in bulk 4He at zero temperature
We present a zero-temperature quantum Monte Carlo calculation of liquid
He immersed in an array of confining potentials. These external potentials
are centered in the lattice sites of a fcc solid geometry and, by modifying
their well depth and range, the system evolves from a liquid phase towards a
progressively localized system which mimics a solid phase. The superfluid
density decreases with increasing order, reaching a value when the Lindemann's ratio of the model equals the experimental
value for solid He.Comment: 5 pages,5 figure
Method to Suppress Isobaric and Polyatomic Interferences for Measurements of Highly Siderophile Elements in Desilicified Geological Samples
Sample decomposition using inverse aqua regia at elevated temperatures and pressures (e.g., Carius tube or highâpressure asher) is the most common method used to extract highly siderophile elements (HSEs: Ru, Rh, Pd, Re, Os, Ir, Pt and Au) from geological samples. Recently, it has been recognised that additional HF desilicification is necessary to better recover HSEs, potentially contained within silicate or oxide minerals in mafic samples, which cannot be dissolved solely by inverse aqua regia. However, the abundance of interfering elements tends to increase in the eluent when conventional ionâexchange purification procedures are applied to desilicified samples. In this study, we developed an improved purification method to determine HSEs in desilicified samples. This method enables the reduction of the ratios of isobaric and polyatomic interferences, relative to the measured intensities of HSE isotope masses, to less than a few hundred parts per million. Furthermore, the total procedural blanks are either comparable to or lower than conventional methods. Thus, this method allows accurate and precise HSE measurements in mafic and ultramafic geological samples, without the need for interference corrections. Moreover, the problem of increased interfering elements, such as Zr for Pd and Cr for Ru, is circumvented for the desilicified samples
ESR Study of (C_5H_{12}N)_2CuBr_4
ESR studies at 9.27, 95.4, and 289.7 GHz have been performed on
(CHN)CuBr down to 3.7 K. The 9.27 GHz data were acquired
with a single crystal and do not indicate the presence of any structural
transitions. The high frequency data were collected with a polycrystalline
sample and resolved two absorbances, consistent with two crystallographic
orientations of the magnetic sites and with earlier ESR studies performed at
300 K. Below T, our data confirm the presence of a spin singlet
ground state.Comment: 2 pages, 4 figs., submitted 23rd International Conference on Low
Temperature Physics (LT-23), Aug. 200
Reliability in digital systems with asymmetrical failure modes
Reliability schemes in digital systems with asymmetrical failure mode
Assessment of monocytic HLA-DR expression in ICU patients: analytical issues for multicentric flow cytometry studies
International audienc
Unraveling the role of ectopic thymic tissue in patients undergoing thymectomy for myasthenia gravis
Extended thymectomy has been considered the goal of surgery for myasthenia gravis (MG) mainly due to the existence of ectopic thymic tissue. Recently, ectopic thymic tissue has attracted increasing attention in patients with MG following thymectomy. However, the specific role of ectopic thymic tissue in patients with MG is still under debate. A systematic search of the literature was performed on PubMed and Medline according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISM) statement. Studies evaluating the rate of ectopic thymic tissue in patients with MG with or without thymoma were included. Extraction was performed for all eligible studies and the rate of ectopic thymic tissue at common locations was calculated. Eighteen out of fifty-nine studies were eligible for inclusion, of which ten studies reported the common locations of ectopic thymic tissue in mediastinal fat. Of these ten studies, the presence of ectopic thymic tissue was investigated in different anatomical locations in 882 patients, of whom, 509 patients (58%) have at least one positive location with the most common ones being anterior mediastinal fat, pericardiophrenic angles, aortopulmonary window, cervical region (pretracheal fat) and lateral to phrenic nerves. On the other hand, nine studies analyzed the influence of the presence of ectopic thymic tissue on the clinical outcomes of MG patients. Of these, six found that the presence of ectopic thymic tissue in MG patients is a significant predictor of poor outcome after thymectomy, however, the other three did not find a significance. Altogether, ectopic thymic tissue is likely to present in more than a half of patients undergoing thymectomy for MG. Besides, MG patients who have ectopic thymic tissue after thymectomy do not seem to have as good outcome as those who have not
Survey of public definitions of the term 'overdiagnosis' in the UK
Objectives: To determine how âoverdiagnosisâ is currently conceptualised among adults in the United Kingdom (UK) in light of previous research, which has found that the term is difficult for the public to understand and awareness is low. This study aims to add to current debates on healthcare in which overdiagnosis is a prominent issue. Design: An observational, web-based survey was administered by a survey company. Setting: Participants completed the survey at a time and location of their choosing. Participants: 390 consenting UK adults aged 50-70 years. Quota sampling was used to achieve approximately equal numbers in three categories of education. Primary outcome measures: Participants were asked whether they had seen or heard the term âoverdiagnosisâ. If they had, they were then invited to explain in a free text field what they understood it to mean. If they had not previously encountered it, they were invited to say what they thought it meant. Responses were coded and interpreted using content analysis and descriptive statistics. Results: Data from 390 participants were analysed. Almost a third (30.0%) of participants reported having previously encountered the term. However, their responses often indicated that they had no knowledge of its meaning. The most prevalent theme consisted of responses related to the diagnosis itself. Subthemes indicated common misconceptions, including an âoverly negative or complicated diagnosisâ, âfalse positive diagnosisâ or âmisdiagnosisâ. Other recurring themes consisted of responses related to testing (i.e. âtoo many testsâ), treatment (e.g. âovertreatmentâ), and patient psychology (e.g. âoverthinkingâ). Responses categorised as consistent with âoverdiagnosisâ (defined as detection of a disease that would not cause symptoms or death) were notably rare (n=10; 2.6%). Conclusions: Consistent with previous research, public awareness of âoverdiagnosisâ in the UK is low and its meaning is often misunderstood or misinterpreted
A Cantilever balcony for a small theater
76 pagesThe slope of the Balcony and height of the stoppings shall first
be considered, so that the steel used in the construction of the balcony
may be designed accordingly.
When "setting up" the sections of the Parquette circle or balcony
in the theater, it is desirable to sight from the eye level of the spectator, which will be considered as 4 feet 2 inches from the floor when
the spectator is seated, (.and 4 feet 10 inches to 5 feet when standing).
The theoretical principles used when fixing the heights of the steppings
upon which the seats are placed are as follows: A point is fixed on the curtain line 4 feet below the stage level,
and from this point, after the distance from the stage, the stepping,
and the floor level is placed, set up the spectator's eyes 4 feet 2 inches
above the floor, vertical with the back rail of the seat. Now from the
4 feet point on the curtain line, a line should be drawn cutting through
the eye of the spectator in the first row, and produced until it cuts
a vertical line set up at the back of the second row. Then from the
point where the vertical and radial lines intersect 5 inches is measured
up and that point gives the eye level of the second row. From the point
below the stage, a line is drawn through the eye level of the second
row, and produced until it intersects the vertical line set up at the
back of the third row, and from that point again measured up 3 inches
for each row, and from each eye level, measured down 4 feet 2 inches
will give the floor level for each stepping
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