5,258 research outputs found
Evaluation of a Cold Staining Method for Acid-Fast Bacilli in Sputum
Comparison between the Ziehl-Neelscn staining method for acid-fast bacilli, applied with and
without heating, was carried out in a controlled investigation using smears prepared from 306
sputum samples collected prior to treatment from suspected cases of pulmonary tuberculosis.
Smear and culture positively were graded and the colour intensity of bacilli recorded. Results
showed that the chance corrected agreement (Kappa) between Z-N and cold methods was only
78%. The sensitivity of the Z-N and cold methods were 84% and 77% respectively when
compared with culture results. Assuming 10% smear positivity among symptomatics reporting to
Peripheral Health Institutions (PHIs), the positive predictive value of the cold method was very
low(53%). When compared to culture, the positive predictive value is 71% for the Z-N method
and 57% for the cold method for a symptomatic population with 15% culture positivity.
In the absence of heating. penetration of the stain was significantly reduced and consequently
the number of bacilli detected was less. The inability to take the stain without heating was seen in
smears from all grades of culture positive samples: thus even heavy positives were missed by the
cold method. The evaluation of the cold method against the standard Z-N method highlights its
limitations and demonstrates that it is not as reliable as the standard Z-N method
Coarsening and Slow-Dynamics in Granular Compaction
We address the problem of the microscopic reorganization of a granular medium
under a compaction process in the framework of Tetris-like models. We point out
the existence of regions of spatial organization which we call domains, and
study their time evolution. It turns out that after an initial transient, most
of the activity of the system is concentrated on the boundaries between
domains. One can then describe the compaction phenomenon as a coarsening
process for the domains, and a progressive reduction of domain boundaries. We
discuss the link between the coarsening process and the slow dynamics in the
framework of a model of active walkers on active substrates.Comment: Revtex 4 pages, 4 figures, in press in PRL. More info
http://axtnt3.phys.uniroma1.it/Tetri
Restriction fragment length polymorphism of Mycobacterium tuberculosis strains from various regions of India, using direct repeat probe
Intraspecies differentiation was studied on 68 M. tuberculosis strains obtained from 6 states of India by
restriction fragment length polymorphism (RFLP) using a direct repeat probe (DR probe) hybridised
with Alu I digest of DNA. Most strains showed polymorphism based patterns that comprised between 2
to 7 bands and were grouped into 26 RFLP types. Of the 11 strains tested from Amritsar, 8 were RFLP
type 5; the remaining 3 were of type 11 and were exclusively confined to this region. The strains from
other regions were more heterogeneous. We confirm that DR-associated RFLP can be an excellent tool
for the differentiation of M. tuberculosis strains. Depending on their geographical origin, these strains can
be differentiated to a large extent by DR fingerprinting
Synthesis of thujane
This article does not have an abstract
Early bactericidal action of pulsed exposure to rifampicin, ethambutol, isoniazid & pyrazinamide in pulmonary tuberculosis patients
The bactericidal action of two therapeutic regimens on Mycobacterium tuberculosis was assessed by
viable counts in serial sputum samples in 49 pulmonary tuberculosis patients being treated with
rifampicin (R), etbambutol (Emb), isoniazid (I) and pyrazinamide (Z) together in a single dose thrice
weekly (REmbIZ3) or with REmb and IZ on alternate days (REmb3IZ3alt). In both groups of patients,
there was a significant reduction (P < 0.02) in the colony forming units (cfu) of M. tuberculosis per
ml of sputum during the first two days of treatment itself. This early bactericidal action (EBA) as well
as the reduction in counts during the subsequent days of treatment were similar (P > 0.2) for both
REmbIZ3 and REmb3IZ3alt regimens indicating that splitting up REmbIZ into REmb on one day and
IZ on the next day in short course chemotherapy (SCC) regimens may not affect the bactericidal action
of the regimens
"Exhaustion" Physics in the Periodic Anderson Model using Iterated Perturbation Theory
We discuss the "exhaustion" problem in the context of the Periodic Anderson
Model using Iterated Perturbation Theory(IPT) within the Dynamical Mean Field
Theory. We find that, despite its limitations, IPT captures the exhaustion
physics, which manifests itself as a dramatic, strongly energy dependent
suppression of the effective Anderson impurity problem. As a consequence, low
energy scales in the lattice case are strongly suppressed compared to the
"Kondo scale" in the single-impurity picture. The IPT results are in
qualitative agreement with recent Quantum Monte Carlo results for the same
problem.Comment: 13 preprint pages including 1 table and 4 eps figures, replaced by
revised version, accepted for publication in Europhysics Letters, added
references and conten
Eulerian Walkers as a model of Self-Organised Criticality
We propose a new model of self-organized criticality. A particle is dropped
at random on a lattice and moves along directions specified by arrows at each
site. As it moves, it changes the direction of the arrows according to fixed
rules. On closed graphs these walks generate Euler circuits. On open graphs,
the particle eventually leaves the system, and a new particle is then added.
The operators corresponding to particle addition generate an abelian group,
same as the group for the Abelian Sandpile model on the graph. We determine the
critical steady state and some critical exponents exactly, using this
equivalence.Comment: 4 pages, RevTex, 4 figure
Group Differential Privacy-Preserving Disclosure of Multi-level Association Graphs
Traditional privacy-preserving data disclosure solutions have focused on protecting the privacy of individual's information with the assumption that all aggregate (statistical) information about individuals is safe for disclosure. Such schemes fail to support group privacy where aggregate information about a group of individuals may also be sensitive and users of the published data may have different levels of access privileges entitled to them. We propose the notion of Eg-Group Differential Privacy that protects sensitive information of groups of individuals at various defined privacy levels, enabling data users to obtain the level of access entitled to them. We present a preliminary evaluation of the proposed notion of group privacy through experiments on real association graph data that demonstrate the guarantees on group privacy on the disclosed data
The Strong Coupling Fixed-Point Revisited
In recent work we have shown that the Fermi liquid aspects of the strong
coupling fixed point of the s-d and Anderson models can brought out more
clearly by interpreting the fixed point as a renormalized Anderson model,
characterized by a renormalized level , resonance width,
, and interaction , and a simple prescription for their
calculation was given using the numerical renormalization group (NRG). These
three parameters completely specify a renormalized perturbation theory (RPT)
which leads to exact expressions for the low temperature behaviour. Using a
combination of the two techniques, NRG to determine ,
, and , and then substituting these in the RPT
expressions gives a very efficient and accurate way of calculating the low
temperature behaviour of the impurity as it avoids the necessity of subtracting
out the conduction electron component. Here we extend this approach to an
Anderson model in a magnetic field, so that , ,
and become dependent on the magnetic field. The de-renormalization
of the renormalized quasiparticles can then be followed as the magnetic field
strength is increased. Using these running coupling constants in a RPT
calculation we derive an expression for the low temperature conductivity for
arbitrary magnetic field strength.Comment: Contribution to JPSJ volume commemorating the 40th anniversary of the
publication of Kondo's original pape
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