81 research outputs found
Search for the exotic Resonance in 340GeV/c -Nucleus Interactions
We report on a high statistics search for the resonance in
-nucleus collisions at 340GeV/c. No evidence for this resonance is
found in our data sample which contains 676000 candidates above
background. For the decay channel and the
kinematic range 0.150.9 we find a 3 upper limit for the
production cross section of 3.1 and 3.5 b per nucleon for reactions with
carbon and copper, respectively.Comment: 5 pages, 4 figures, modification of ref. 43 and 4
Measurement of the Omega_c Lifetime
We present the measurement of the lifetime of the Omega_c we have performed
using three independent data samples from two different decay modes. Using a
Sigma- beam of 340 GeV/c we have obtained clean signals for the Omega_c
decaying into Xi- K- pi+ pi+ and Omega- pi+ pi- pi+, avoiding topological cuts
normally used in charm analysis. The short but measurable lifetime of the
Omega_c is demonstrated by a clear enhancement of the signals at short but
finite decay lengths. Using a continuous maximum likelihood method we
determined the lifetime to be tau(Omega_c) = 55 +13-11(stat) +18-23(syst) fs.
This makes the Omega_c the shortest living weakly decaying particle observed so
far. The short value of the lifetime confirms the predicted pattern of the
charmed baryon lifetimes and demonstrates that the strong interaction plays a
vital role in the lifetimes of charmed hadrons.Comment: 15 pages, including 7 figures; gzipped, uuencoded postscrip
Analytical expressions for stopping-power ratios relevant for accurate dosimetry in particle therapy
In particle therapy, knowledge of the stopping-power ratios (STPRs) of the
ion beam for air and water is necessary for accurate ionization chamber
dosimetry. Earlier work has investigated the STPRs for pristine carbon ion
beams, but here we expand the calculations to a range of ions (1 <= z <= 18) as
well as spread out Bragg peaks (SOBPs) and provide a theoretical in-depth study
with a special focus on the parameter regime relevant for particle therapy. The
Monte Carlo transport code SHIELD-HIT is used to calculate complete
particle-fluence spectra which are required for determining STPRs according to
the recommendations of the International Atomic Energy Agency (IAEA).
We confirm that the STPR depends primarily on the current energy of the ions
rather than on their charge z or absolute position in the medium. However,
STPRs for different sets of stopping-power data for water and air recommended
by the International Commission on Radiation Units & Measurements (ICRU) are
compared, including also the recently revised data for water, yielding
deviations up to 2% in the plateau region. In comparison, the influence of the
secondary particle spectra on the STPR is about two orders of magnitude smaller
in the whole region up till the practical range. The gained insights enable us
to propose an analytic approximation for the STPR for both pristine and SOBPs
as a function of penetration depth, which parametrically depend only on the
initial energy and the residual range of the ion, respectively.Comment: 21 pages, 5 figures, fixed bug with figures in v
Charge Asymmetries for D, D_s and Lambda_c Production in Sigma- - Nucleus Interactions at 340 GeV/c
CERN experiment WA89 has studied charmed particles produced by a Sigma^- beam
at 340 GeV/c on nuclear targets. Production of particles which have light
quarks in common with the beam is compared to production of those which do not.
Considerable production asymmetries between D^- and D^p, D_s^ and D_s^+ and
Lambda_c and Antilambda_c are observed. The results are compared with pion beam
data and with theoretical calculations.Comment: LaTeX ; 16 pages including 4 ps figure
Search for the pentaquark candidate (1540) in the hyperon beam experiment WA89
We report on a high-statistics search for the \t1540 resonance in
-nucleus collisions at 340 \gevc1 . No evidence for this resonance
was found in our data sample which contains 13 millions
decays above background. For the decay channel and the
kinematic range 0.05 we find the production cross section to be
1.8 b per nucleon at 99% CL.Comment: 5 pages, 4 figure
An unusual cause of atrial tachycardia in a young patient with lymphoma.
Contains fulltext :
80026.pdf (publisher's version ) (Closed access)An 8-year-old girl who was recently diagnosed as having anaplastic large-cell lymphoma presented with atrial tachycardia and dilated cardiomyopathy, which is a contraindication for further treatment with cardio-toxic chemotherapy. After starting digoxin therapy, the dilated cardiomyopathy resolved. Repeated episodes of atrial tachycardia in this case were not caused by any common disorder but were due to mechanical stimulation by a central venous catheter. Central venous catheters are known to cause mainly ventricular arrhythmias. However, atrial tachycardia is a rare manifestation of arrhythmia due to mechanical stimulation of the heart by a central venous catheter, with potentially important cardiovascular consequences
Practice guidelines for the diagnosis and management of microcytic anemias due to genetic disorders of iron metabolism or heme synthesis
During recent years, our understanding of the pathogenesis of inherited microcytic anemias has gained from the identification of several genes and proteins involved in systemic and cellular iron metabolism and heme syntheses. Numerous case reports illustrate that the implementation of these novel molecular discoveries in clinical practice has increased our understanding of the presentation, diagnosis, and management of these diseases. Integration of these insights into daily clinical practice will reduce delays in establishing a proper diagnosis, invasive and/or costly diagnostic tests, and unnecessary or even detrimental treatments. To assist the clinician, we developed evidence-based multidisciplinary guidelines on the management of rare microcytic anemias due to genetic disorders of iron metabolism and heme synthesis. These genetic disorders may present at all ages, and therefore these guidelines are relevant for pediatricians as well as clinicians who treat adults. This article summarizes these clinical practice guidelines and includes background on pathogenesis, conclusions, and recommendations and a diagnostic flowchart to facilitate using these guidelines in the clinical setting
Whole exome sequencing in the diagnostic workup of patients with a bleeding diathesis
INTRODUCTION: Bleeding assessment tools and laboratory phenotyping often remain inconclusive in patients with a haemorrhagic diathesis. AIM: To describe the phenotype and genetic profile of patients with a bleeding tendency. METHODS: Whole exome sequencing (WES) was incorporated in the routine diagnostic pathway of patients with thrombocytopenia (n = 17), platelet function disorders (n = 19) and an unexplained bleeding tendency (n = 51). The analysis of a panel of 126 OMIM (Online Mendelian Inheritance in Man) genes involved in thrombosis and haemostasis was conducted, and if negative, further exome-wide analysis was performed if informed consent given. RESULTS: Eighteen variants were detected in 15 patients from a total of 87 patients (17%). Causative variants were observed in MYH9 (two cases), SLFN14, P2RY12 and GP9. In addition, one case was considered solved due to combined carriership of F7 and F13A1 variants and one with combined carriership of F2, F8 and VWF, all variants related to secondary haemostasis protein aberrations. Two variants of uncertain significance (VUS) were found in two primary haemostasis genes: GFI1B and VWF. Eight patients were carriers of autosomal recessive disorders. Exome-wide analysis was performed in 54 cases and identified three variants in candidate genes. CONCLUSION: Based on our findings, we conclude that performing WES at the end of the diagnostic trajectory can be of additive value to explain the complete bleeding phenotype in patients without a definite diagnosis after conventional laboratory tests. Discovery of combinations of (novel) genes that predispose to bleeding will increase the diagnostic yield in patients with an unexplained bleeding diathesis
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