103 research outputs found

    Exact Shannon entropies for the multidimensional harmonic states

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    In this work we determine and discuss the entropic uncertainty measures of Shannon type for all the discrete stationary states of the multidimensional harmonic systems directly in terms of the states' hyperquantum numbers, the dimensionality and the oscillator strength. We have found that these entropies have a monotonically increasing behavior when both the dimensionality and the population of the states are increasingComment: Accepted and Published in Physica

    Epoxy Composites Using Wood Pulp Components as Fillers

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    The components of wood, especially lignin and cellulose, have great potential for improving the properties of polymer composites. In this chapter, we discuss some of the latest developments from our lab on incorporating wood-based materials into epoxy composites. Lignosulfonate was used as a flame retardant and cellulose nanocrystals were used as reinforcing materials. Lignosulfonate will disperse well in epoxy, but phase separates during curing. An epoxidation reaction was developed to immobilize the lignosulfonate during curing. The lignosulfonate–epoxy composites were characterized using microcombustion and cone calorimetry tests. Cellulose also has poor interfacial adhesion to hydrophobic polymer matrices. Cellulose fibers and nanocrystals aggregate when placed in epoxy resin, resulting in very poor dispersion. The cellulose nanocrystal surface was modified with phenyl containing materials to disrupt cellulose interchain hydrogen bonding and improve dispersion in the epoxy resin. The cellulose nanocrystal – epoxy composites were characterized for mechanical strength using tensile tests, water barrier properties using standardized water absorption, glass transition temperatures using differential calorimetry, and aggregation and dispersion using microscopic techniques

    Halo effects on fusion cross section in 4,6He+64Zn collision around and below the Coulomb barrier

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    The structure of the halo nuclei is expected to influence the fusion mechanism at energies around and below the Coulomb barrier. Here new data of 4He+64Zn at sub-barrier energies are presented which cover the same energy region of previous measurements of 6He+64Zn. The fusion cross section was measured by using an activation technique where the radioactive evaporation residues produced in the reaction were identified by the X-ray emission which follows their electron capture decay. By comparing the two system, we observe an enhancement on the fusion cross section in the reaction induced by 6He, at energy below the Coulomb barrier. It is shown that this enhancement seems to be due to static properties of halo 2n 6He nucleus

    Quasielastic backscattering and barrier distributions for the 6, 7Li + 64Zn systems

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    Excitation functions of quasielastic scattering at backward angles were measured for the weakly bound 6Li and 7Li projectiles on a 64Zn target at energies around the Coulomb barrier. The corresponding barrier distributions were derived from the experimental cross sections. The experimental data were analyzed within the coupled-channel model using a double-folding potential as the bare potential. Inelastic excitations of the target, the 7Li first excited state, and 6Li, 7Li resonant state(s), corresponding to sequential breakup, were included in the calculations. The comparison between the data and coupled-channel predictions shows that the effects of channels not included in the calculations, such as direct breakup and transfers, are much larger for 6Li than for 7Li

    Involvement of Mhc Loci in immune responses that are not Ir-gene-controlled

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    Twenty-nine randomly chosen, soluble antigens, many of them highly complex, were used to immunize mice of two strains, C3H and B10.RIII. Lymphnode cells from the immunized mice were restimulated in vitro with the priming antigens and the proliferative response of the cells was determined. Both strains were responders to 28 of 29 antigens. Eight antigens were then used to immunize 11 congenic strains carrying different H-2 haplotypes, and the T-cell proliferative responses of these strains were determined. Again, all the strains responded to seven of the eight antigens. These experiments were then repeated, but this time -antibodies specific for the A (AA) or E (EE) molecules were added to the culture to block the in vitro responsiveness. In all but one of the responses, inhibition with both A-specific and E-specific antibodies was observed. The response to one antigen (Blastoinyces) was exceptional in that some strains were nonresponders to this antigen. Furthermore, the response in the responder strains was blocked with A-specific, but not with E-specific, antibodies. The study demonstrates that responses to antigens not controlled by Irr genes nevertheless require participation of class II Mhc molecules. In contrast to Ir gene-controlled responses involving either the A- or the E-molecule controlling loci (but never both), the responses not Ir-controlled involve participation of both A- and E-controlling loci. The lack of Ir-gene control is probably the result of complexity of the responses to multiple determinants. There is thus no principal difference between responses controlled and those not controlled by Ir genes: both types involve the recognition of the antigen, in the context of Mhc molecules

    Heavy residue excitation functions for the collisions 6, 7Li + 64Zn near the Coulomb barrier

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    Excitation functions for the production of heavy residues have been measured for the collisions 6, 7Li+64Zn at energies around and below the Coulomb barrier. The cross sections for heavy residue production have been measured using an activation technique, detecting off-line the characteristic atomic x-rays emitted in the electron capture decay of the reaction products. The experimental relative yields of the residues have been compared with statistical model calculations performed by using the code cascade. Such a comparison suggests that heavy residue production is dominated by complete fusion at above-barrier energies, whereas different processes like incomplete fusion and/or transfer become dominant in the sub-barrier energy region. The heavy residue excitation function ratio between the 6Li- and 7Li-induced collisions shows an increasing trend as the energy decreases below the barrier

    Fusion and direct reactions for the system 6He + 64Zn at and below the Coulomb barrier

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    Fusion and transfer + breakup channels have been studied in the collision induced by the two-neutron-halo 6He on a 64Zn target at energies from below to above the Coulomb barrier. For comparison, the reaction induced by the stable isotope 4He on the same target has been studied. The fusion cross section has been measured by using an activation technique, detecting off-line the delayed x-ray activity following the electron capture decay of the evaporation residues. New measurements of the 4He + 64Zn fusion cross section at sub-barrier energies have been performed in order to cover the same energy range of the 6He + 64Zn fusion cross section and to compare the excitation functions for the two systems down to the lowest energy data point measured for 6He. From the new comparison a sub-barrier fusion enhancement has been observed in the 6He case with respect to the 4He one whereas no effect on the 6He fusion cross section has been seen at energies above the barrier. It has been concluded that such enhancement seems to be due to the diffuse halo structure properties of the 6He nucleus. Moreover, the reactions induced by 6He have shown a strong yield of α particles coming from direct processes

    Mass correlation between light and heavy reaction products in multinucleon transfer 197Au+130Te collisions

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    We studied multinucleon transfer reactions in the 197Au+130Te system at Elab=1.07 GeV by employing the PRISMA magnetic spectrometer coupled to a coincident detector. For each light fragment we constructed, in coincidence, the distribution in mass of the heavy partner of the reaction. With a Monte Carlo method, starting from the binary character of the reaction, we simulated the de-excitation process of the produced heavy fragments to be able to understand their final mass distribution. The total cross sections for pure neutron transfer channels have also been extracted and compared with calculations performed with the grazing code

    International consensus statement on the diagnosis and management of autosomal dominant polycystic kidney disease in children and young people

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    These recommendations were systematically developed on behalf of the Network for Early Onset Cystic Kidney Disease (NEOCYST) by an international group of experts in autosomal dominant polycystic kidney disease (ADPKD) from paediatric and adult nephrology, human genetics, paediatric radiology and ethics specialties together with patient representatives. They have been endorsed by the International Pediatric Nephrology Association (IPNA) and the European Society of Paediatric Nephrology (ESPN). For asymptomatic minors at risk of ADPKD, ongoing surveillance (repeated screening for treatable disease manifestations without diagnostic testing) or immediate diagnostic screening are equally valid clinical approaches. Ultrasonography is the current radiological method of choice for screening. Sonographic detection of one or more cysts in an at-risk child is highly suggestive of ADPKD, but a negative scan cannot rule out ADPKD in childhood. Genetic testing is recommended for infants with very-early-onset symptomatic disease and for children with a negative family history and progressive disease. Children with a positive family history and either confirmed or unknown disease status should be monitored for hypertension (preferably by ambulatory blood pressure monitoring) and albuminuria. Currently, vasopressin antagonists should not be offered routinely but off-label use can be considered in selected children. No consensus was reached on the use of statins, but mTOR inhibitors and somatostatin analogues are not recommended. Children with ADPKD should be strongly encouraged to achieve the low dietary salt intake that is recommended for all children

    Evidence of strong effects of the 11Be halo structure on reaction processes at energies around the Coulomb barrier

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    The collision induced by the three Beryllium isotopes, 9, 10, 11Be, on 64Zn target were investigated at Ec.m. ≈ 1.4 the Coulomb barrier. Elastic scattering angular distributions were measured for the 9, 10Be collisions whereas, in the 11Be case the quasielastic scattering angular distribution was obtained. A strong damping of the quasielastic cross-section was observed in the 11Be case, especially in the angular range around the Coulomb-nuclear interference peak. In this latter case a large total-reaction cross-section is found, more than a factor of two larger than the ones extracted in the reactions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the 11Be case could be attributed to transfer and/or break-up events
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