428 research outputs found
Duality properties of Gorringe-Leach equations
In the category of motions preserving the angular momentum's direction,
Gorringe and Leach exhibited two classes of differential equations having
elliptical orbits. After enlarging slightly these classes, we show that they
are related by a duality correspondence of the Arnold-Vassiliev type. The
specific associated conserved quantities (Laplace-Runge-Lenz vector and
Fradkin-Jauch-Hill tensor) are then dual reflections one of the othe
Serum protein changes in Caplan's syndrome
The British literature on Caplan's syndrome is
briefly reviewed with particular reference to the pathogenesis
of the pulmonary lesions and an investigation is described
which was designed to throw fresh light upon this.Statistical analysis of the results revealed an
association between the levels of several serum protein
fractions am> the severity of the lung lesions independently
of the severity of arthritis. Elevation of α2- and
γ-globulins and reduction of albumin and of the albumin/
α2-globulin ratio are consistent with the tuberculous theory
of the aetiology of these lesions, but a trend was also
observed toward3 higher levels of ß-globulin with increasing
severity of pulronary lesions. Rheumatoid arthritis itself
rarely produces this effect and no increase of ß-globulin
has been reported in tuberculosis.The previously observed association between the
presence of "Caplan lesions" in the lungs and positive
haemagglutination tests for rheumatoid arthritis was confirmed
and a significant correlation demonstrated between the agglutination titre and the ß-globulin level.The literature on the nature of the rheumatoid factor
is reviewed and the conclusion reached that it exists naturally
as a 19s macroglobulin migrating electrophoretically as a
(ß2-globulin but that transformation to a 22s γ-globulin occurs
when serum is stored in the liquid stateBased on this conclusion and on the three-fold
relationship observed between the severity of "Caplan lesions",
the haemagglutination titre and the p-globulin level, a
hypothesis is proposed that the nodular pulmonary lesions
described by Caplan and perhaps some other lesions associated
with rheumatoid arthritis such as subcutaneous necrobiotic
nodules may be sites of synthesis of the rheumatoid factor.
It is further suggested that the raw material for this synthesis
may consist of ß-glycoprotein derived from the ground-substance
of degenerating collagenous tissue.Observations consistent with this hypothesis are
quoted from the literature and several experiments are suggested
which, if done, might support or refute the hypothesis
The hyperfine transition in light muonic atoms of odd Z
The hyperfine (hf) transition rates for muonic atoms have been re-measured
for select light nuclei, using neutron detectors to evaluate the time
dependence of muon capture. For F = 5.6 (2)
s for the hf transition rate, a value which is considerably more
accurate than previous measurements. Results are also reported for Na, Al, P,
Cl, and K; that result for P is the first positive identification.Comment: 12 pages including 5 tables and 4 figures, RevTex, submitted to Phys.
Rev.
Ortho-para transition rate in -molecular hydrogen and the proton's induced pseudoscalar coupling
We report a measurement of the ortho-para transition rate in the pp
molecule. The experiment was conducted at TRIUMF via the measurement of the
time dependence of the 5.2 MeV neutrons from muon capture in liquid hydrogen.
The measurement yielded an ortho-para rate s that is substantially larger than the
earlier result of Bardin {\it et al.} We discuss the striking implications for
the proton's induced pseudoscalar coupling .Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
Double radiative pion capture on hydrogen and deuterium and the nucleon's pion cloud
We report measurements of double radiative capture in pionic hydrogen and
pionic deuterium. The measurements were performed with the RMC spectrometer at
the TRIUMF cyclotron by recording photon pairs from pion stops in liquid
hydrogen and deuterium targets. We obtained absolute branching ratios of for hydrogen and for deuterium, and
relative branching ratios of double radiative capture to single radiative
capture of for hydrogen
and for
deuterium. For hydrogen, the measured branching ratio and photon energy-angle
distributions are in fair agreement with a reaction mechanism involving the
annihilation of the incident on the cloud of the target proton.
For deuterium, the measured branching ratio and energy-angle distributions are
qualitatively consistent with simple arguments for the expected role of the
spectator neutron. A comparison between our hydrogen and deuterium data and
earlier beryllium and carbon data reveals substantial changes in the relative
branching ratios and the energy-angle distributions and is in agreement with
the expected evolution of the reaction dynamics from an annihilation process in
S-state capture to a bremsstrahlung process in P-state capture. Lastly, we
comment on the relevance of the double radiative process to the investigation
of the charged pion polarizability and the in-medium pion field.Comment: 44 pages, 7 tables, 13 figures, submitted to Phys. Rev.
Observation of double radiative capture on pionic hydrogen
We report the first observation of double radiative capture on pionic
hydrogen. The experiment was conducted at the TRIUMF cyclotron using the RMC
spectrometer, and detected --ray coincidences following stops
in liquid hydrogen. We found the branching ratio for double radiative capture
to be . The measured
branching ratio and angle-energy distributions support the theoretical
prediction of a dominant contribution from the
annihilation mechanism.Comment: 4 Pages, 4 Figures. accepted for publication in Phys. Rev. Let
Caste, Kinship, and Life Course: Rethinking Women's Work and Agency in Rural South India
This paper reexamines the linkages between women's work, agency, and well-being based on a household survey and in-depth interviews conducted in rural Tamil Nadu in 2009 and questions the prioritization of workforce participation as a path to gender equality. It emphasizes the need to unpack the nature of work performed by and available to women and its social valuation, as well as women's agency, particularly its implications for decision making around financial and nonfinancial household resources in contexts of socioeconomic change. The effects of work participation on agency are mediated by factors like age and stage in the life cycle, reproductive success, and social location – especially of caste – from which women enter the workforce
Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision
We report a measurement of the positive muon lifetime to a precision of 1.0
parts per million (ppm); it is the most precise particle lifetime ever
measured. The experiment used a time-structured, low-energy muon beam and a
segmented plastic scintillator array to record more than 2 x 10^{12} decays.
Two different stopping target configurations were employed in independent
data-taking periods. The combined results give tau_{mu^+}(MuLan) =
2196980.3(2.2) ps, more than 15 times as precise as any previous experiment.
The muon lifetime gives the most precise value for the Fermi constant:
G_F(MuLan) = 1.1663788 (7) x 10^-5 GeV^-2 (0.6 ppm). It is also used to extract
the mu^-p singlet capture rate, which determines the proton's weak induced
pseudoscalar coupling g_P.Comment: Accepted for publication in Phys. Rev. Let
Analysis of the Mitogen-activated protein kinase kinase 4 (MAP2K4) tumor suppressor gene in ovarian cancer
<p>Abstract</p> <p>Background</p> <p><it>MAP2K4 </it>is a putative tumor and metastasis suppressor gene frequently found to be deleted in various cancer types. We aimed to conduct a comprehensive analysis of this gene to assess its involvement in ovarian cancer.</p> <p>Methods</p> <p>We screened for mutations in <it>MAP2K4 </it>using High Resolution Melt analysis of 149 primary ovarian tumors and methylation at the promoter using Methylation-Specific Single-Stranded Conformation Polymorphism analysis of 39 tumors. We also considered the clinical impact of changes in <it>MAP2K4 </it>using publicly available expression and copy number array data. Finally, we used siRNA to measure the effect of reducing <it>MAP2K4 </it>expression in cell lines.</p> <p>Results</p> <p>In addition to 4 previously detected homozygous deletions, we identified a homozygous 16 bp truncating deletion and a heterozygous 4 bp deletion, each in one ovarian tumor. No promoter methylation was detected. The frequency of <it>MAP2K4 </it>homozygous inactivation was 5.6% overall, and 9.8% in high-grade serous cases. Hemizygous deletion of <it>MAP2K4 </it>was observed in 38% of samples. There were significant correlations of copy number and expression in three microarray data sets. There was a significant correlation between <it>MAP2K4 </it>expression and overall survival in one expression array data set, but this was not confirmed in an independent set. Treatment of JAM and HOSE6.3 cell lines with <it>MAP2K4 </it>siRNA showed some reduction in proliferation.</p> <p>Conclusions</p> <p><it>MAP2K4 </it>is targeted by genetic inactivation in ovarian cancer and restricted to high grade serous and endometrioid carcinomas in our cohort.</p
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