637 research outputs found
The Social Relations Approach, empowerment and women factory workers in Malaysia
This article discusses the empowerment of women factory workers in Malaysia through the lens of Kabeer’s Social Relations Approach. The approach offers an institutional analysis of how gender inequality is produced and calls for the overall terms of exchange and cooperation to be shifted in women’s favour. Its application shows that Malaysian women factory workers face significant challenges, due to the character of institutions, and women’s difficulties in adopting and internalising the notion of ‘empowerment’
Reversing Blood Flows Act through klf2a to Ensure Normal Valvulogenesis in the Developing Heart
Heart valve anomalies are some of the most common congenital heart defects, yet neither the genetic nor the epigenetic forces guiding heart valve development are well understood. When functioning normally, mature heart valves prevent intracardiac retrograde blood flow; before valves develop, there is considerable regurgitation, resulting in reversing (or oscillatory) flows between the atrium and ventricle. As reversing flows are particularly strong stimuli to endothelial cells in culture, an attractive hypothesis is that heart valves form as a developmental response to retrograde blood flows through the maturing heart. Here, we exploit the relationship between oscillatory flow and heart rate to manipulate the amount of retrograde flow in the atrioventricular (AV) canal before and during valvulogenesis, and find that this leads to arrested valve growth. Using this manipulation, we determined that klf2a is normally expressed in the valve precursors in response to reversing flows, and is dramatically reduced by treatments that decrease such flows. Experimentally knocking down the expression of this shear-responsive gene with morpholine antisense oligonucleotides (MOs) results in dysfunctional valves. Thus, klf2a expression appears to be necessary for normal valve formation. This, together with its dependence on intracardiac hemodynamic forces, makes klf2a expression an early and reliable indicator of proper valve development. Together, these results demonstrate a critical role for reversing flows during valvulogenesis and show how relatively subtle perturbations of normal hemodynamic patterns can lead to both major alterations in gene expression and severe valve dysgenesis
Integrating transposable elements in the 3D genome
Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome
Meta-analyses of chemotherapy for locally advanced and metastatic pancreatic cancer: results of secondary end points analyses
In advanced pancreatic cancer, level one evidence has established a significant survival advantage with chemotherapy, compared to best supportive care. The treatment-associated toxicity needs to be evaluated. This study examines the secondary outcome measures for chemotherapy in advanced pancreatic cancer using meta-analyses. A systematic review was undertaken employing Cochrane methodology, with search of databases, conference proceedings and trial registers. The secondary end points were progression-free survival (PFS)/time to progression (TTP) (summarised using the hazard ratio (HR)), response rate and toxicity (summarised using relative risk). There was no significant advantage of 5FU combinations vs 5FU alone for TTP (HR=1.02; 95% CI=0.85–1.23) and toxicity. Progression-free survival (HR 0.78; CI 0.70–0.88), TTP (HR=0.85; 95% CI=0.72–0.99) and overall response rate (RR=0.56; 95% CI=0.46–0.68) were significantly better for gemcitabine combination chemotherapy, but offset by the greater grade 3/4 toxicity thrombocytopenia (RR=1.94; 95% CI=1.32–2.84), leucopenia (RR=1.46; 95% CI=1.15–1.86), neutropenia (RR=1.48; 95% CI=1.07–2.05), nausea (RR=1.77; 95% CI=1.37–2.29), vomiting (RR=1.64; 95% CI=1.24–2.16) and diarrhoea (RR=2.73; 95% CI=1.87–3.98). There is no significant advantage on secondary end point analyses for administering 5FU in combination over 5FU alone. There is improved PFS/TTP and response rate, with gemcitabine-based combinations, although this comes with greater toxicity
Measurement of B(Ds+ -->ell+ nu) and the Decay Constant fDs From 600/pb of e+e- Annihilation Data Near 4170 MeV
We examine e+e- --> Ds^-D_s^{*+} and Ds^{*-}Ds^{+} interactions at 4170 MeV
using the CLEO-c detector in order to measure the decay constant fDs with good
precision. Previously our measurements were substantially higher than the most
precise lattice based QCD calculation of (241 +/- 3) MeV. Here we use the D_s^+
--> ell^+ nu channel, where the ell^+ designates either a mu^+ or a tau^+, when
the tau^+ --> pi^+ anti-nu. Analyzing both modes independently, we determine
B(D_s^+ --> mu^+ nu)= 0.565 +/- 0.045 +/- 0.017)%, and B(D_s^+ --> mu^+ nu)=
(6.42 +/- 0.81 +/- 0.18)%. We also analyze them simultaneously to find an
effective value of B^{eff}(D_s^+ --> mu^+ nu)= (0.591 +/- 0.037 +/- 0.018)% and
fDs=(263.3 +/- 8.2 +/- 3.9) MeV. Combining with the CLEO-c value determined
independently using D_s^+ --> tau^+ nu, tau^+ --> e^+ nu anti-nu decays, we
extract fDs=(259.5 +/- 6.6 +/- 3.1) MeV. Combining with our previous
determination of B(D^+ --> mu^+ nu), we extract the ratio fDs/fD+=1.26 +/- 0.06
+/- 0.02. No evidence is found for a CP asymmetry between Gamma(D_s^+ -->
mu^+\nu) and \Gamma(D_s^- --> mu^- nu); specifically the fractional difference
in rates is measured to be (4.8 +/- 6.1)%. Finally, we find B(D_s^+ --> e^+ nu)
< 1.2x10^{-4} at 90% confidence level.Comment: 26 pages, 16 figure
Determination of the D0 -> K+pi- Relative Strong Phase Using Quantum-Correlated Measurements in e+e- -> D0 D0bar at CLEO
We exploit the quantum coherence between pair-produced D0 and D0bar in
psi(3770) decays to study charm mixing, which is characterized by the
parameters x and y, and to make a first determination of the relative strong
phase \delta between doubly Cabibbo-suppressed D0 -> K+pi- and Cabibbo-favored
D0bar -> K+pi-. We analyze a sample of 1.0 million D0D0bar pairs from 281 pb^-1
of e+e- collision data collected with the CLEO-c detector at E_cm = 3.77 GeV.
By combining CLEO-c measurements with branching fraction input and
time-integrated measurements of R_M = (x^2+y^2)/2 and R_{WS} = Gamma(D0 ->
K+pi-)/Gamma(D0bar -> K+pi-) from other experiments, we find \cos\delta = 1.03
+0.31-0.17 +- 0.06, where the uncertainties are statistical and systematic,
respectively. In addition, by further including external measurements of charm
mixing parameters, we obtain an alternate measurement of \cos\delta = 1.10 +-
0.35 +- 0.07, as well as x\sin\delta = (4.4 +2.7-1.8 +- 2.9) x 10^-3 and \delta
= 22 +11-12 +9-11 degrees.Comment: 37 pages, also available through
http://www.lns.cornell.edu/public/CLNS/2007/. Incorporated referee's comment
Observation of Upsilon(2S) -> eta Upsilon(1S) and search for related transitions
We report the first observation of the transition Upsilon(2S) > eta
Upsilon(1S), with branching fraction B=(2.1+0.7-0.6(stat.)+-0.3(syst.)) x
10^{-4} and statistical significance 5.3 sigma. Data were acquired with the
CLEO detector at the CESR e+ e- symmetric collider. This is the first process
observed involving a b-quark spin flip. Upper limits at 90% confidence level
for related processes, in units of 10^{-4}, are B[Upsilon(2S) -> pi0
Upsilon(1S)] eta Upsilon(1S)]
pi0 Upsilon(1S)] pi0 Upsilon(2S)] < 5.1.Comment: 9 pages, 2 figures, available through
http://www.lns.cornell.edu/public/CLNS/, submitted to PRL. Revised systematic
errors. Slightly shortened to conform to PRL line coun
Search for Light CP-odd Higgs in Radiative Decays of Upsilon(1S)
We search for a non-SM-like CP-odd Higgs boson (a0_1) with m(a0_1)< 2m(b) in
radiative decays of the Upsilon(1S), using 21.5M Upsilon(1S) mesons directly
produced in e+e- annihilation. We investigate a0_1 --> tau+tau- and a0_1 -->
mu+mu- decay channels. No significant signal is found. We obtain upper limits
on the product of B(Upsilon(1S)-->gamma a0_1) and B(a0_1-->tau+tau-) or
B(a0_1-->mu+mu-). Our tau+tau- results are almost two orders of magnitude more
stringent than previous upper limits. Our data provide no evidence for a Higgs
state with a mass of 214 MeV decaying to mu+mu-. Existence of such a state was
previously proposed as an explanation for 3 Sigma+ --> p mu+mu- events, having
mu+mu- masses just above the kinematic threshold, observed by the HyperCP
experiment. Our results constrain NMSSM models.Comment: 12 pages, available through http://www.lns.cornell.edu/public/CLNS/,
submitted to PR
Precision Measurement of B(D+ -> mu+ nu) and the Pseudoscalar Decay Constant fD+
We measure the branching ratio of the purely leptonic decay of the D+ meson
with unprecedented precision as B(D+ -> mu+ nu) = (3.82 +/- 0.32 +/-
0.09)x10^(-4), using 818/pb of data taken on the psi(3770) resonance with the
CLEO-c detector at the CESR collider. We use this determination to derive a
value for the pseudoscalar decay constant fD+, combining with measurements of
the D+ lifetime and assuming |Vcd| = |Vus|. We find fD+ = (205.8 +/- 8.5 +/-
2.5) MeV. The decay rate asymmetry [B(D+ -> mu+ nu)-B(D- -> mu- nu)]/[B(D+ ->
mu+ nu)+B(D- -> mu- nu)] = 0.08 +/- 0.08, consistent with no CP violation. We
also set 90% confidence level upper limits on B(D+ -> tau+ nu) < 1.2x10^(-3)
and B(D+ -> e+ nu) < 8.8x10^(-6).Comment: 24 pages, 11 figures and 6 tables, v2 replaced some figure vertical
axis scales, v3 corrections from PRD revie
Dalitz plot analysis of the D+ -> K- pi+ pi+ decay
We present a Dalitz plot analysis of the decay D+ -> K- pi+ pi+ based on 281
pb-1 of e+e- collision data produced at the psi(3770) by CESR and observed with
the CLEO-c detector. We select 67086 candidate events with a small, ~1.1%,
background for this analysis. When using a simple isobar model our results are
consistent with the previous measurements done by E791. Since our sample is
considerably larger we can explore alternative models. We find better agreement
with data when we include an isospin-two pi+pi+ S-wave contribution. We apply a
quasi model-independent partial wave analysis and measure the amplitude and
phase of the K pi and pi+pi+ S waves in the range of invariant masses from the
threshold to the maximum in this decay.Comment: 9 pages postscript,also available through
http://www.lepp.cornell.edu/public/CONF/2007, Submitted to EPS/HEP2007: July
19-25, 2007, Manchester, Englan
- …