353 research outputs found
Three-centre cluster structure in 11C and 11B
Studies of the 16O(9Be,alpha 7Be)14C, 7Li(9Be,alpha 7Li)5He and 7Li(9Be,alpha
alpha t)5He reactions at E(beam)=70 and 55 MeV have been performed using
resonant particle spectroscopy techniques. The 11C excited states decaying into
alpha+7Be(gs) are observed between 8.5 and 13.5 MeV. The alpha+7Li(gs),
alpha+7Li*(4.652 MeV) and t+8Be(gs) decays of 11B excited states between 9 and
19 MeV are observed. The decay processes are used to indicate the possible
three-centre 2alpha+3He (2alpha+3H) cluster structure of observed states. This
cluster structure is more prominent in the positive-parity states, where two
rotational bands with large deformations are suggested. Excitations of some of
the observed T=1/2 resonances coincide with the energies of previously measured
T=3/2 isobaric analogs of the 11Be states,indicating that these states may have
mixed isospin.Comment: Contribution for the proceedings of the NUSTAR'05: NUclear STructure,
Astrophysics and Reactions, University of Surrey, Guildford, UK; accepted for
publication in Journal of Physics
Study of the Fusion-Fission Process in the Reaction
Fusion-fission and fully energy-damped binary processes of the
Cl+Mg reaction were investigated using particle-particle
coincidence techniques at a Cl bombarding energy of E
8 MeV/nucleon. Inclusive data were also taken in order to determine the partial
wave distribution of the fusion process. The fragment-fragment correlation data
show that the majority of events arises from a binary-decay process with a
relatively large multiplicity of secondary light-charged particles emitted by
the two primary excited fragments in the exit channel. No evidence is observed
for ternary-breakup processes, as expected from the systematics recently
established for incident energies below 15 MeV/nucleon and for a large number
of reactions. The binary-process results are compared with predictions of
statistical-model calculations. The calculations were performed using the
Extended Hauser-Feshbach method, based on the available phase space at the
scission point of the compound nucleus. This new method uses
temperature-dependent level densities and its predictions are in good agreement
with the presented experimental data, thus consistent with the fusion-fission
origin of the binary fully-damped yields.Comment: 30 pages standard REVTeX file, 10 eps Figures; to be published at the
European Physical Journal A - Hadrons and Nucle
Case-finding of chronic obstructive pulmonary disease with questionnaire, peak flow measurements and spirometry : a cross-sectional study
Peer reviewedPublisher PD
Structure of 12Be: intruder d-wave strength at N=8
The breaking of the N=8 shell-model magic number in the 12Be ground state has
been determined to include significant occupancy of the intruder d-wave
orbital. This is in marked contrast with all other N=8 isotones, both more and
less exotic than 12Be. The occupancies of the 0 hbar omega neutron p1/2-orbital
and the 1 hbar omega, neutron d5/2 intruder orbital were deduced from a
measurement of neutron removal from a high-energy 12Be beam leading to bound
and unbound states in 11Be.Comment: 5 pages, 2 figure
4He decay of excited states in 14C
A study of the 7Li(9Be,4He 10Be)2H reaction at E{beam}=70 MeV has been
performed using resonant particle spectroscopy techniques and provides the
first measurements of alpha-decaying states in 14C. Excited states are observed
at 14.7, 15.5, 16.4, 18.5, 19.8, 20.6, 21.4, 22.4 and 24.0 MeV. The
experimental technique was able to resolve decays to the various particle bound
states in 10Be, and provides evidence for the preferential decay of the high
energy excited states into states in 10Be at ~6 MeV. The decay processes are
used to indicate the possible cluster structure of the 14C excited states.Comment: accepted for publication in PR
Highly deformed Ca configurations in Si + C
The possible occurrence of highly deformed configurations in the Ca
di-nuclear system formed in the Si + C reaction is investigated
by analyzing the spectra of emitted light charged particles. Both inclusive and
exclusive measurements of the heavy fragments (A 10) and their
associated light charged particles (protons and particles) have been
made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding
energies of Si) = 112 MeV and 180 MeV by using the {\sc ICARE}
charged particle multidetector array. The energy spectra, velocity
distributions, and both in-plane and out-of-plane angular correlations of light
charged particles are compared to statistical-model calculations using a
consistent set of parameters with spin-dependent level densities. The analysis
suggests the onset of large nuclear deformation in Ca at high spin.Comment: 33 pages, 11 figure
Extended Hauser-Feshbach Method for Statistical Binary-Decay of Light-Mass Systems
An Extended Hauser-Feshbach Method (EHFM) is developed for light heavy-ion
fusion reactions in order to provide a detailed analysis of all the possible
decay channels by including explicitly the fusion-fission phase-space in the
description of the cascade chain. The mass-asymmetric fission component is
considered as a complex-fragment binary-decay which can be treated in the same
way as the light-particle evaporation from the compound nucleus in
statistical-model calculations. The method of the phase-space integrations for
the binary-decay is an extension of the usual Hauser-Feshbach formalism to be
applied to the mass-symmetric fission part. The EHFM calculations include
ground-state binding energies and discrete levels in the low excitation-energy
regions which are essential for an accurate evaluation of the phase-space
integrations of the complex-fragment emission (fission). In the present
calculations, EHFM is applied to the first-chance binary-decay by assuming that
the second-chance fission decay is negligible. In a similar manner to the
description of the fusion-evaporation process, the usual cascade calculation of
light-particle emission from the highly excited complex fragments is applied.
This complete calculation is then defined as EHFM+CASCADE. Calculated
quantities such as charge-, mass- and kinetic-energy distributions are compared
with inclusive and/or exclusive data for the S+Mg and
Cl+C reactions which have been selected as typical examples.
Finally, the missing charge distributions extracted from exclusive measurements
are also successfully compared with the EHFM+CASCADE predictions.Comment: 34 pages, 6 Figures available upon request, Phys. Rev. C (to be
published
Identifying Asthma genetic signature patterns by mining Gene Expression BIG Datasets using Image Filtering Algorithms
Asthma is a treatable but incurable chronic inflammatory disease affecting more than 14% of the UAE population. Asthma is still a clinical dilemma as there is no proper clinical definition of asthma, unknown definitive underlying mechanisms, no objective prognostic tool nor bedside noninvasive diagnostic test to predict complication or exacerbation. Big Data in the form of publicly available transcriptomics can be a valuable source to decipher complex diseases like asthma. Such an approach is hindered by technical variations between different studies that may mask the real biological variations and meaningful, robust findings. A large number of datasets of gene expression microarray images need a powerful tool to properly translate the image intensities into truly differential expressed genes between conditioned examined from the noise. Here we used a novel bioinformatic method based on the coefficient of variance to filter nonvariant probes with stringent image analysis processing between asthmatic and healthy to increase the power of identifying accurate signals hidden within the heterogeneous nature of asthma. Our analysis identified important signaling pathways members, namely NFKB and TGFB pathways, to be differentially expressed between severe asthma and healthy controls. Those vital pathways represent potential targets for future asthma treatment and can serve as reliable biomarkers for asthma severity. Proper image analysis for the publicly available microarray transcriptomics data increased its usefulness to decipher asthma and identify genuine differentially expressed genes that can be validated across different datasets
On the errors-in-variables model with equality and inequality constraints for selected numerical examples
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