952 research outputs found
Patient Associated Factors that Affect Adherence to Warfarin Therapy in a Tertiary Referral Hospital in Kenya
Warfarin is the most widely used oral anticoagulant but non-adherence to its therapy contributes significantly to sub-optimal anticoagulation control. A crosssectional study was carried out among 147 adult outpatients at Kenyatta National Hospital to determine the level of adherence and explore the associated factors. Adherence was associated with age, gender heart valve surgery, alcohol consumption, and cost of treatment. On multivariate analysis, the independent variables associated with adequate adherence were age (OR = 0.429, 95% CI = 0.228-0.808; p = 0.009), gender (OR = 0.299, 95% CI = 0.123-0.728; p = 0.008) and the type of thromboembolic disease (OR = 0.385, 95% CI = 0.214-0.690; p = 0.001). Adherence was better among females, older age groups and patients who had undergone heart valve surgery. Adherence was poorer among males, younger participants and patients with venous thromboembolism. We suggest that medication adherence counseling to warfarin therapy should be emphasized in poor-adherent patient populations.Key words: Warfarin, adherence, patient factors, Keny
Conductivity in a symmetry broken phase: Spinless fermions with corrections
The dynamic conductivity of strongly correlated electrons in
a symmetry broken phase is investigated in the present work. The model
considered consists of spinless fermions with repulsive interaction on a simple
cubic lattice. The investigated symmetry broken phase is the charge density
wave (CDW) with wave vector which occurs at
half-filling. The calculations are based on the high dimensional approach, i.e.
an expansion in the inverse dimension is used. The finite dimensionality
is accounted for by the inclusion of linear terms in and the true finite
dimensional DOS. Special care is paid to the setup of a conserving
approximation in the sense of Baym/Kadanoff without inconsistencies. The
resulting Bethe-Salpeter equation is solved for the dynamic conductivity in the
non symmetry broken and in the symmetry broken phase (AB-CDW). The
dc-conductivity is reduced drastically in the CDW. Yet it does not vanish in
the limit due to a subtle cancellation of diverging mobility and
vanishing DOS. In the dynamic conductivity the energy gap
induced by the symmetry breaking is clearly discernible. In addition, the
vertex corrections of order lead to an excitonic resonance lying within
the gap.Comment: 23 pages, 19 figures included with psfig, Revtex; Physical Review
B15, in press (October/November 1996) depending on the printer/screen driver,
it might be necessary to comment out figures 3,4,5,10,11,12,19 and have them
printed separatel
Linked Cluster Expansion Around Mean-Field Theories of Interacting Electrons
A general expansion scheme based on the concept of linked cluster expansion
from the theory of classical spin systems is constructed for models of
interacting electrons. It is shown that with a suitable variational formulation
of mean-field theories at weak (Hartree-Fock) and strong (Hubbard-III) coupling
the expansion represents a universal and comprehensive tool for systematic
improvements of static mean-field theories. As an example of the general
formalism we investigate in detail an analytically tractable series of ring
diagrams that correctly capture dynamical fluctuations at weak coupling. We
introduce renormalizations of the diagrammatic expansion at various levels and
show how the resultant theories are related to other approximations of similar
origin. We demonstrate that only fully self-consistent approximations produce
global and thermodynamically consistent extensions of static mean field
theories. A fully self-consistent theory for the ring diagrams is reached by
summing the so-called noncrossing diagrams.Comment: 17 pages, REVTEX, 13 uuencoded postscript figures in 2 separate file
Dynamical correlations in multiorbital Hubbard models: Fluctuation-exchange approximations
We study the two band degenerate Hubbard model using the Fluctuation Exchange
approximation (FLEX) method and compare the results with Quantum Monte-Carlo
calculations. Both the self-consistent and the non-self-consistent versions of
the FLEX scheme are investigated. We find that, contrary to the one band case,
in the multiband case, good agreement with the Quantum Monte-Carlo results is
obtained within the electron-electron T-matrix approximation using the full
renormalization of the one-particle propagators. The crossover to strong
coupling and the formation of satellites is more clearly visible in the
non-self-consistent scheme. Finally we discuss the behavior of the FLEX for
higher orbital degeneracy.Comment: 18 pages with 12 PS figure
Exact Critical Exponents for Pseudo-Particles in the Kondo Problem
Exact critical exponents of the Green functions for pseudo-fermions and slave
bosons in the SU() Anderson model with are obtained by
using the Bethe ansatz solution and boundary conformal field theory. They are
evaluated exactly for mixed valence systems and Kondo systems with crystalline
fields. The results agree with the prediction of Menge and M\"uller-Hartmann,
which coincide with those of the X-ray problem. Some implication of our results
in one-dimensional chiral systems is also discussed.Comment: 9 pages, no figure
Vaccine-Induced Subcutaneous Granulomas in Goats Reflect Differences in Host–Mycobacterium Interactions between BCG- and Recombinant BCG-Derivative Vaccines
Tuberculous granulomas are highly dynamic structures reflecting the complex host–mycobacterium interactions. The objective of this study was to compare granuloma development at the site of vaccination with BCG and its recombinant derivatives in goats. To characterize the host response, epithelioid cells, multinucleated giant cells (MNGC), T cell subsets, B cells, plasma cells, dendritic cells and mycobacterial antigen were labelled by immunohistochemistry, and lipids and acid-fast bacteria (AFB) were labelled by specific staining. Granulomas with central caseous necrosis developed at the injection site of most goats though lesion size and extent of necrosis differed between vaccine strains. CD4(+) T and B cells were more scarce and CD8(+) cells were more numerous in granulomas induced by recombinant derivatives compared to their parental BCG strain. Further, the numbers of MNGCs and cells with lipid bodies were markedly lower in groups administered with recombinant BCG strains. Microscopic detection of AFB and mycobacterial antigen was rather frequent in the area of central necrosis, however, the isolation of bacteria in culture was rarely successful. In summary, BCG and its recombinant derivatives induced reproducibly subcutaneous caseous granulomas in goats that can be easily monitored and surgically removed for further studies. The granulomas reflected the genetic modifications of the recombinant BCG-derivatives and are therefore suitable models to compare reactions to different mycobacteria or TB vaccines
Deflection of carbon dioxide laser and helium‐neon laser beams in a long‐pulse relativistic electron beam diode
Deflection of carbon dioxide and helium‐neon laser beams has been used to measure plasma and neutral density gradients during the operating mode and after the shorting time of a long‐pulse field‐emission electron beam diode. Plasma density gradients of (1014–1015) cm−4 were observed throughout the diode during the final microsecond of the 2–3 μs electron beam pulse. The neutral density gradient was less than 1×1018 cm−4 during the electron beam pulse. Upon diode shorting, neutral density gradients increased to (1018–1019) cm−4 over ∼1 μs, and decayed over many microseconds. Plasma density gradients of ∼1015 cm−4 were also observed after shorting. These experiments demonstrate the value of carbon‐dioxide laser and helium‐neon laser deflection for diagnosing plasma and neutral particles in long‐pulse electron beam diodes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70220/2/RSINAK-62-7-1776-1.pd
Auxiliary particle theory of threshold singularities in photoemission and X-ray absorption spectra: Test of a conserving T-matrix approximation
We calculate the exponents of the threshold singularities in the
photoemission spectrum of a deep core hole and its X-ray absorption spectrum in
the framework of a systematic many-body theory of slave bosons and
pseudofermions (for the empty and occupied core level). In this representation,
photoemission and X-ray absorption can be understood on the same footing; no
distinction between orthogonality catastrophe and excitonic effects is
necessary. We apply the conserving slave particle T-matrix approximation
(CTMA), recently developed to describe both Fermi and non-Fermi liquid behavior
systems with strong local correlations, to the X-ray problem as a test case.
The numerical results for both photoemission and X-ray absorption are found to
be in agreement with the exact infrared powerlaw behavior in the weak as well
as in the strong coupling regions. We point out a close relation of the CTMA
with the parquet equation approach of Nozi{\`e}res et al.Comment: 10 pages, 9 figures, published versio
Fermi and non-Fermi liquid behavior in quantum impurity systems: Conserving slave boson theory
The question of Fermi liquid vs. non-Fermi liquid behavior induced by strong
correlations is one of the prominent problems in metallic local moment systems.
As standard models for such systems, the SU(N)xSU(M) Anderson impurity models
exhibit both Fermi liquid and non-Fermi liquid behavior, depending on their
symmetry. Taking the Anderson model as an example, these lectures first give an
introduction to the auxiliary boson method to describe correlated systems
governed by a strong, short-range electronic repulsion. It is then shown how to
include the relevant low-lying excitations (coherent spin flip and charge
fluctuation processes), while preserving the local gauge symmetry of the model.
This amounts to a conserving T-matrix approximation (CTMA). We prove a
cancellation theorem showing that the CTMA incorporates all leading and
subleading infrared singularities at any given order in a self-consistent loop
expansion of the free energy. As a result, the CTMA recovers the correct
infrared behavior of the auxiliary particle propagators, indicating that it
correctly describes both the Fermi and the non-Fermi regimes of the Anderson
model.Comment: 37 pages, LaTeX, style file included, 10 postscript figures; to
appear in Proceedings of the XXXVIII Cracow School of Theoretical Physics,
Zakopane, Poland, June 1-10, 199
Possible Interruption of Malaria Transmission, Highland Kenya, 2007–2008
Annual insecticide spraying and artemisinin combination therapy may stop transmission
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