34,456 research outputs found
Polio survivors’ perceptions of the meaning of quality of life and strategies used to promote participation in everyday activities
This article is made available through the Brunel Open Access Publishing Fund.Introduction: The term ‘post-polio syndrome’ (PPS) is used to describe new and late manifestations of poliomyelitis that occur later in life. Research in this area has focused upon health status rather than its effect on quality of life. Aim: To gain an in-depth understanding of the meaning of quality of life for polio survivors and to determine the type of strategies that are used by people with PPS and the support that they consider as important to facilitate participation in everyday life activities that have an impact on their quality of life. Method: Six focus groups were conducted with 51 participants from two regions in England. Data were audio-taped and analysed using thematic analysis. Results: Our research found that polio survivors used terms used to describe quality of life which could be associated with that of happiness. Our research has identified resolvable factors that influence quality of life namely inaccessible environments, attitudes of health-care professionals and societal attitudes. Polio survivors have tried alternative therapies, chiefly acupuncture and massage, and found them to be effective in enhancing their quality of life. Conclusion: It is suggested that health-care professionals should consider factors which influence happiness and implement a person-centred approach with the views of the polio survivor being listened to. The three factors that influenced quality of life could be resolved by health-care professionals and by society. With regard to strategies used, we suggest that polio survivors should have access to the treatments that they perceive as important, although further research is required to design optimal interventions for this client group
Effect of uniaxial strain on the structural and magnetic phase transitions in BaFeAs
We report neutron scattering experiments probing the influence of uniaxial
strain on both the magnetic and structural order parameters in the parent iron
pnictide compound, BaFeAs. Our data show that modest strain fields
along the in-plane orthorhombic b-axis can affect significant changes in phase
behavior simultaneous to the removal of structural twinning effects. As a
result, we demonstrate in BaFeAs samples detwinned via uniaxial strain
that the in-plane C symmetry is broken by \textit{both} the structural
lattice distortion \textit{and} long-range spin ordering at temperatures far
above the nominal (strain-free), phase transition temperatures. Surprising
changes in the magnetic order parameter of this system under relatively small
strain fields also suggest the inherent presence of magnetic domains
fluctuating above the strain-free ordering temperature in this material.Comment: 4 pages, 3 figure
Evolution with hole doping of the electronic excitation spectrum in the cuprate superconductors
The recent scanning tunnelling results of Alldredge et al on Bi-2212 and of
Hanaguri et al on Na-CCOC are examined from the perspective of the BCS/BEC
boson-fermion resonant crossover model for the mixed-valent HTSC cuprates. The
model specifies the two energy scales controlling the development of HTSC
behaviour and the dichotomy often now alluded to between nodal and antinodal
phenomena in the HTSC cuprates. Indication is extracted from the data as to how
the choice of the particular HTSC system sees these two basic energy scales
(cursive-U, the local pair binding energy and, Delta-sc, the nodal BCS-like gap
parameter) evolve with doping and change in degree of metallization of the
structurally and electronically perturbed mixed-valent environment.Comment: 19 pages, 5 figure
A Multivariate Training Technique with Event Reweighting
An event reweighting technique incorporated in multivariate training
algorithm has been developed and tested using the Artificial Neural Networks
(ANN) and Boosted Decision Trees (BDT). The event reweighting training are
compared to that of the conventional equal event weighting based on the ANN and
the BDT performance. The comparison is performed in the context of the physics
analysis of the ATLAS experiment at the Large Hadron Collider (LHC), which will
explore the fundamental nature of matter and the basic forces that shape our
universe. We demonstrate that the event reweighting technique provides an
unbiased method of multivariate training for event pattern recognition.Comment: 20 pages, 8 figure
The structures of Micrococcus lysodeikticus catalase, its ferryl intermediate (compound II) and NADPH complex
The crystal structure of the bacterial catalase from Micrococcus lysodeikticus has been refined using the gene-derived sequence both at 0.88 Angstrom resolution using data recorded at 110 K and at 1.5 Angstrom resolution with room-temperature data. The atomic resolution structure has been refined with individual anisotropic atomic thermal parameters. This has revealed the geometry of the haem and surrounding protein, including many of the H atoms, with unprecedented accuracy and has characterized functionally important hydrogen-bond interactions in the active site. The positions of the H atoms are consistent with the enzymatic mechanism previously suggested for beef liver catalase. The structure reveals that a 25 Angstrom long channel leading to the haem is filled by partially occupied water molecules, suggesting an inherent facile access to the active site. In addition, the structures of the ferryl intermediate of the catalase, the so-called compound II, at 1.96 Angstrom resolution and the catalase complex with NADPH at 1.83 Angstrom resolution have been determined. Comparison of compound II and the resting state of the enzyme shows that the binding of the O atom to the iron (bond length 1.87 Angstrom) is associated with increased haem bending and is accompanied by a distal movement of the iron and the side chain of the proximal tyrosine. Finally, the structure of the NADPH complex shows that the cofactor is bound to the molecule in an equivalent position to that found in beef liver catalase, but that only the adenine part of NADPH is visible in the present structure
The evolution of antiferromagnetic susceptibility to uniaxial pressure in Ba(Fe{1-x}Co{x})2As2
Neutron diffraction measurements are presented measuring the responses of
both magnetic and structural order parameters of parent and lightly Co-doped
Ba(Fe{1-x}Co{x})2As2 under the application of uniaxial pressure. We find that
the uniaxial pressure induces a thermal shift in the onset of antiferromagnetic
order that grows as a percentage of T_N as Co-doping is increased and the
superconducting phase is approached. Additionally, as uniaxial pressure is
increased within parent and lightly-doped Ba(Fe{1-x}Co{x})2As2 on the first
order side of the tricritical point, we observe a decoupling between the onsets
of the orthorhombic structural distortion and antiferromagnetism. Our findings
place needed constraints on models exploring the nematic susceptibility of the
bilayer pnictides in the tetragonal, paramagnetic regime.Comment: 10 pages, 7 figure
Mott-Hubbard Transition and Anderson Localization: Generalized Dynamical Mean-Field Theory Approach
Density of states, dynamic (optical) conductivity and phase diagram of
strongly correlated and strongly disordered paramagnetic Anderson-Hubbard model
are analyzed within the generalized dynamical mean field theory (DMFT+\Sigma
approximation). Strong correlations are accounted by DMFT, while disorder is
taken into account via the appropriate generalization of self-consistent theory
of localization. The DMFT effective single impurity problem is solved by
numerical renormalization group (NRG) and we consider the three-dimensional
system with semi-elliptic density of states. Correlated metal, Mott insulator
and correlated Anderson insulator phases are identified via the evolution of
density of states and dynamic conductivity, demonstrating both Mott-Hubbard and
Anderson metal-insulator transition and allowing the construction of complete
zero-temperature phase diagram of Anderson-Hubbard model. Rather unusual is the
possibility of disorder induced Mott insulator to metal transition.Comment: 15 pages, 16 figure
Neutron scattering study of magnetic phase separation in nanocrystalline LaCaMnO
We demonstrate that magnetic phase separation and competing spin order in the
colossal magnetoresistive (CMR) manganites can be directly explored via tuning
strain in bulk samples of nanocrystalline LaCaMnO. Our results
show that strain can be reversibly frozen into the lattice in order to
stabilize coexisting antiferromagnetic domains within the nominally
ferromagnetic metallic state of LaCaMnO. The measurement of
tunable phase separation via magnetic neutron powder diffraction presents a
direct route of exploring the correlated spin properties of phase separated
charge/magnetic order in highly strained CMR materials and opens a potential
avenue for realizing intergrain spin tunnel junction networks with enhanced CMR
behavior in a chemically homogeneous material.Comment: 6 pages, 4 figures. New figure and text added to manuscrip
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