318 research outputs found
Les langues africaines sur la Toile: étude des cas haoussa, somali, lingala et isixhosa [The African Languages on the Internet: Case studies for Hausa, Somali, Lingala and isiXhosa]
Moerzeke-Kastel, gemeente Hamme, Wal-Zwijn en Groot Schoor, Fase 1, Sigmaproject
Dit rapport werd ingediend bij het agentschap samen met een aantal afzonderlijke digitale bijlagen. Een aantal van deze bijlagen zijn niet inbegrepen in dit pdf document en zijn niet online beschikbaar. Sommige bijlagen (grondplannen, fotos, spoorbeschrijvingen, enz.) kunnen van belang zijn voor een betere lezing en interpretatie van dit rapport. Indien u deze bijlagen wenst te raadplegen kan u daarvoor contact opnemen met: [email protected]
Advances on the modeling of the time evolution of dynamic aperture of hadron circular accelerators
Determining a model for the time scaling of the dynamic aperture of a circular accelerator is a topic of strong interest and intense research efforts in accelerator physics. The motivation arises in the possibility of finding a method to reliably extrapolate the results of numerical simulations well beyond what is currently possible in terms of CPU time. In earlier work, a proposal for a model based on Nekhoroshev theorem and Kolmogorov-Arnold-Moser theory was made. This model has been studied in detail and proved successful in describing the evolution of the dynamic aperture in numerical simulations, however a number of shortcomings had been identified and new models are proposed in this paper, which solve the observed issues. The new models have been benchmarked against numerical simulations for a simple system, the 4D H\ue9non map, as well as a realistic, non-linear representation of the beam dynamics in the LHC at 6.5 TeV providing in both cases excellent results
Van der Waals complexes between carbonyl fluoride and boron trifluoride observed in liquefied argon, krypton, and nitrogen: A FTIR and ab initio study
The IR spectra (4000-400 cm-1) of COF2/BF3 mixtures, dissolved in liquefied argon (LAr), krypton (LKr), and nitrogen (LN2), have been examined. In all spectra evidence was found for the formation of a 1:1 van der Waals complex. Using spectra recorded at several temperatures between 81 and 172 K the complexation enthalpies ΔH°in LAr, LKr, and LN2 were determined to be -11.8(3), -10.6(3), and -7.8(3) kJ mol-1, respectively. A theoretical study, using both density functional theory at the B3LYP/6- 311++G(d,p) level and ab initio at the MP2/aug-cc-pVTZ level, indicates that the complexation can occur either via the oxygen or via a fluorine atom of COF2. From a comparison of the experimental and calculated frequencies it was concluded that the observed complex bands are due to a species in which the boron atom coordinates with the oxygen lone pairs. The complexation energy Δ(c)E is obtained from the ΔH°by correcting for solvent influences, and thermal contributions equals -15.0(6) kJ mol-1. This value agrees well with the MP2/aug-cc-pVTZ level result, -12.4 kJ mol-1. The complexation entropy ΔS°has been found to be influenced by the solvent and is correlated with ΔH°. This correlation reflects the existence of the compensation effect for the thermodynamics of van der Waals complexes
Solvent effect on vibrational frequencies: Cryosolution experiments and density functional calculations
FTIR spectra of C2H6, COF2 and CH3F in the vapour phase and in solutions in liquefied argon, krypton and xenon were investigated. Vapour- solvent frequency shifts (SFS) were determined for all IR-active fundamentals of the studied compounds. In parallel, the SFS values were calculated using the Self-Consistent Isodensity Polarizable Continuum Model (SCIPCM) at the B3LYP/6-311 + +G(d,p) level. Comparison of the experimental and the calculated data shows reasonable agreement only for three most intense IR bands under investigation, i.e., the C=O and the CF2 asymmetric stretching modes of COF2, and the C-F stretching mode of CH3F. For the other bands of COF2, CH3F and for all the bands of C2H6 the results of SCIPCM calculations underestimate the observed SFS significantly. It is concluded that at least for the modes with relatively small (δμ/δQ)(o) values, the electrostatic interactions give a minor contribution to SFS
Orientational diffusion of methyl groups in crystalline CH3F: An infrared study
The mid-infrared (4000-400 cm-1) spectra of polycrystalline methyl fluoride have been investigated at temperatures between 8 and 85 K. Least-squares band fitting was performed for all fundamental bands belonging to symmetric and asymmetric vibrations of the methyl group, and the contributions of inhomogeneous broadening and vibrational and orientational relaxation to the bandwidths have been evaluated. From the temperature dependence of the bandwidths, using the modified Rakov approach, the activation enthalpy, ΔH*, and activation entropy, ΔS*, for orientational diffusion of the methyl groups have been determined to be ΔH* = 0.85(7) kJ mol-1 and ΔS* = -7(1) J mol-1 K-1
FTIR spectra of liquid argon/liquid nitrogen mixtures: Evidence for the existence of a 1:1 bonded species Ar·N2
The mid-infrared spectra of liquid phase argon/nitrogen (80-121 K), krypton/nitrogen (78-121 K) and xenon/nitrogen (80-123 K) mixtures are reported. Superposed on the broad, collision-induced N2 band, for the Ar/N2 and the Kr/N2 mixtures a weak band, proving the existence of a 1:1 species Ar·N2 or Kr·N2, was observed near 2326 cm-1. Using spectra recorded at different temperatures, the complexation enthalpy of Ar·N2 was determined to be -1.5(4) kJ mol-1
Low grade mosaic for a complex supernumerary ring chromosome 18 in an adult patient with multiple congenital anomalies
Background. Several cases have been reported of patients with a ring chromosome 18 replacing one of the normal chromosomes 18. Less common are patients with a supernumerary ring chromosomes 18. High resolution whole genome examination in patients with multiple congenital abnormalities might reveal cytogenetic abnormalities of an unexpected complexity. Results. We report a 24 years old male patient with lower spinal anomalies, hypospadia, bifid scrotum, cryptorchism, anal atresia, kidney stones, urethra anomalies, radial dysplasia, and a hypoplastic thumb. Some of the anomalies overlap with the VACTERL association. Chromosome analysis of cultured peripheral blood lymphocytes revealed an additional ring chromosome in 13% of the metaphases. Both parents had a normal karyotype, demonstrating the de novo origin of this ring chromosome. FISH analysis using whole chromosome paints showed that the additional chromosomal material was derived from chromosome 18. Chromosome analysis of cultured fibroblasts revealed only one cell with the supernumerary ring chromosome in the 400 analyzed. To characterize the ring chromosome in more detail peripheral blood derived DNA was analyzed using SNP-arrays. The array results indicated a 5 Mb gain of the pericentromeric region of chromosome 18q10-q11.2. FISH analysis using BAC-probes located in the region indicated the presence of 6 signals on the r(18) chromosome. In addition, microsatellite analysis demonstrated that the unique supernumerary ring chromosome was paternally derived and both normal copies showed biparental disomy. Conclusions. We report on an adult patient with multiple congenital abnormalities who had in 13% of his cells a unique supernumerary ring chromosome 18 that was composed of 6 copies of the 5 Mb gene rich region of 18q11
Adult-onset autoinflammation caused by somatic mutations in UBA1:A Dutch case series of patients with VEXAS
Background: A novel autoinflammatory syndrome was recently described in male patients who harbored somatic mutations in the X-chromosomal UBA1 gene. These patients were characterized by adult-onset, treatment-refractory inflammation with fever, cytopenia, dysplastic bone marrow, vacuoles in myeloid and erythroid progenitor cells, cutaneous and pulmonary inflammation, chondritis, and vasculitis, which is abbreviated as VEXAS. Objective: This study aimed to (retrospectively) diagnose VEXAS in patients who had previously been registered as having unclassified autoinflammation. We furthermore aimed to describe clinical experiences with this multifaceted, complex disease. Methods: A systematic reanalysis of whole-exome sequencing data from a cohort of undiagnosed patients with autoinflammation from academic hospitals in The Netherlands was performed. When no sequencing data were available, targeted Sanger sequencing was applied in cases with high clinical suspicion of VEXAS. Results: A total of 12 male patients who carried mutations in UBA1 were identified. These patients presented with adult-onset (mean age 67 years, range 47-79 years) autoinflammation with systemic symptoms, elevated inflammatory parameters, and multiorgan involvement, most typically involving the skin and bone marrow. Novel features of VEXAS included interstitial nephritis, cardiac involvement, stroke, and intestinal perforation related to treatment with tocilizumab. Although many types of treatment were initiated, most patients became treatment-refractory, with a high mortality rate of 50%. Conclusion: VEXAS should be considered in the differential diagnosis of males with adult-onset autoinflammation characterized by systemic symptoms and multiorgan involvement. Early diagnosis can prevent unnecessary diagnostic procedures and provide better prognostic information and more suitable treatment options, including stem cell transplantation
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