2,607 research outputs found
Integrating housing wealth into the social safety net : the elderly in Moscow
The elderly in Russia have often been among those least able to cope with all the changes that have taken place during the transition. Unlike the situation prior to reform-when pensions were stable-they now face considerable uncertainty. If they have not been in poverty, many have been close to it. While the elderly have experienced difficulties, they have also been the beneficiaries of a very large transfer of wealth. In Russia, as in most transition economies, housing was privatized, under giveaway terms. As a result, although many elderly households have low incomes, based on their wealth, their deprivation would appear to be less serious. Unfortunately, in the absence of a developed financial system, it is difficult to use this wealth without selling it. In Russia, all households, not just the elderly, have not been able to borrow. The existence of such large unencumbered wealth holdings by lower income elderly households creates an opportunity to provide what might be termed"housing safety net insurance"at low public cost. More than reducing the incidence of poverty, such schemes could allow also many of the elderly to be able to move out of poverty and into middle income status. The authors explain why many of the elderly in the former Soviet Union (FSU), not just in Russia, are likely to have so much housing wealth. Then they discuss how financial instruments could access this wealth. The authors also discuss the empirical situation of the elderly in Moscow, illustrating the potential demand for such products. Finally, they suggest that the results for Moscow are likely to be similar in many other FSU countries because these countries also have elderly populations who also own a great deal of unencumbered housing wealth.Environmental Economics&Policies,Public Health Promotion,Payment Systems&Infrastructure,Banks&Banking Reform,Health Economics&Finance,Health Monitoring&Evaluation,Banks&Banking Reform,Environmental Economics&Policies,Economic Theory&Research,Health Economics&Finance
Robust Magnetic Polarons in Type-II (Zn,Mn)Te Quantum Dots
We present evidence of magnetic ordering in type-II (Zn, Mn) Te quantum dots.
This ordering is attributed to the formation of bound magnetic polarons caused
by the exchange interaction between the strongly localized holes and Mn within
the dots. In our photoluminescence studies, the magnetic polarons are detected
at temperatures up to ~ 200 K, with a binding energy of ~ 40 meV. In addition,
these dots display an unusually small Zeeman shift with applied field (2 meV at
10 T). This behavior is explained by a small and weakly temperature-dependent
magnetic susceptibility due to anti-ferromagnetic coupling of the Mn spins
Regulation of stanniocalcin-1 secretion by BeWo cells and first trimester human placental tissue from normal pregnancies and those at increased risk of developing preeclampsia.
Stanniocalcin-1 (STC-1) is a multi-functional glycosylated peptide present in the plasma of healthy women postpartum and increased further in pregnancies complicated by preeclampsia. Although the STC-1 gene is expressed by the placenta what regulates its secretion and from which cells at the feto-maternal interface is unknown. Here, we demonstrate for the first time that the syncytiotrophoblast and cytotrophoblast are a major site of STC-1 protein expression in first trimester placental tissue. Further, in response to low oxygen, first trimester chorionic villous tissue from pregnancies at increased risk of developing preeclampsia secreted significantly more STC-1 than normal tissue under the same conditions. Using the human trophoblast cell line BeWo we have shown that low oxygen increased the secretion of STC-1 but it required co-stimulation with the Adenosine-3', 5'-cyclic monophosphate (cAMP) analogue, 8-Bromo adenosine-3', 5'-cyclic monophosphate cAMP (8 Br-cAMP) to reach significance. Inhibition of Hypoxia inducible factor 2α (HIF-2α) and the Phosphatidylinositol-3 kinase (PI3 -Kinase)/AKT/Serum and glucocorticoid-induced kinase-1(SGK-1) pathway resulted in significant inhibition of STC-1 secretion. As both low oxygen and cAMP are known to play a central role in placental function, their regulation of STC-1 points to a potentially important role in the maintenance of a normal healthy pregnancy and we would hypothesize that it may act to protect against prolonged placental hypoxia seen in preeclampsia
Increased angiogenic factor secretion by decidual natural killer cells from pregnancies with high uterine artery resistance alters trophoblast function.
STUDY QUESTION
Are the concentrations of factors secreted by decidual natural killer (dNK) cells from pregnancies at high risk of poor spiral artery remodelling different to those secreted from pregnancies at low risk?
SUMMARY ANSWER
Expression levels of PLGF, sIL-2R, endostatin and angiogenin were significantly increased by dNK cells from high-risk pregnancies, and angiogenin and endostatin were found to alter trophoblast function.
WHAT IS KNOWN ALREADY
During early pregnancy, maternal uterine spiral arteries are remodelled from small diameter, low-flow, high-resistance vessels into larger diameter, higher flow vessels, with low-resistance. This change is essential for the developing fetus to obtain sufficient oxygen and nutrients. dNK cells have been implicated in this process.
STUDY DESIGN, SIZE, DURATION
dNK cells were isolated from first trimester terminations of pregnancies (obtained with local ethical approval) screened for normal- or high-resistance index, indicative of cases least (21%) likely to have developed pre-eclampsia had the pregnancy not been terminated (n = 18 each group). Secreted factors and the effects of these on the trophoblast cell line, SGHPL-4, were assessed in vitro.
PARTICIPANTS/MATERIALS, SETTING, METHODS
A multiplex assay was used to assess dNK cell-secreted factors. SGHPL-4 cell functions were assessed using time-lapse microscopy, 3D invasion assays, endothelial-like tube formation ability and western blot analysis.
MAIN RESULTS AND THE ROLE OF CHANCE
The expression levels of PLGF (P < 0.01), sIL-2R (P < 0.01), endostatin (P < 0.05) and angiogenin (P < 0.05) were significantly increased by dNK cells from high-risk pregnancies. Endostatin significantly decreased SGHPL-4 invasion (P < 0.05), SGHPL-4 tube formation (P < 0.05) and SGHPL-4 Aktser473 phosphorylation (P < 0.05). Angiogenin significantly decreased SGHPL-4 invasion (P < 0.05), but increased SGHPL-4 tube formation (P < 0.01) and decreased SGHPL-4 Aktser473 phosphorylation (P < 0.05).
LIMITATIONS, REASONS FOR CAUTION
The culture of dNK cells and protein concentrations in vitro may not fully represent the in vivo situation. Although SGHPL-4 cells are extravillous trophoblast derived, further studies would be needed to confirm the roles of angiogenin and endostatin in vivo.
WIDER IMPLICATIONS OF THE FINDINGS
The altered expression of secreted factors of dNK cells may contribute to pregnancy disorders associated with poor spiral artery remodelling.
STUDY FUNDING/COMPETING INTEREST(S)
This study was supported by the Wellcome Trust (project reference 091550). R.F. was a recipient of a PhD studentship from the Division of Biomedical Sciences, St. George's, University of London. The authors have no conflict of interests
Electron impact excitations of S2 molecules
Low-energy electron impact excitations of S_2 molecules are studied using the
fixed-bond R-matrix method based on state-averaged complete active space SCF
orbitals. Integral cross sections are calculated for elastic electron collision
as well as impact excitation of the 7 lowest excited electronic states. Also,
differential cross sections are obtained for elastic collision and excitation
of the a^1 Delta_g, b^1 Sigma_g^+ and B^3 Sigma_u^- states. The integrated
cross section of optically allowed excitation of the B^3 Sigma_u^- state agrees
reasonably well with the available theoretical result.Comment: 12 pages, 3 figures. Chemical Physics Letters, in pres
Can k-NN imputation improve the performance of C4.5 with small software project data sets? A comparative evaluation
Missing data is a widespread problem that can affect the ability to use data to construct effective prediction systems. We investigate a common machine learning technique that can tolerate missing values, namely C4.5, to predict cost using six real world software project databases. We analyze the predictive performance after using the k-NN missing data imputation technique to see if it is better to tolerate missing data or to try to impute missing values and then apply the C4.5 algorithm. For the investigation, we simulated three missingness mechanisms, three missing data patterns, and five missing data percentages. We found that the k-NN imputation can improve the prediction accuracy of C4.5. At the same time, both C4.5 and k-NN are little affected by the missingness mechanism, but that the missing data pattern and the missing data percentage have a strong negative impact upon prediction (or imputation) accuracy particularly if the missing data percentage exceeds 40%
Triisopropylsilylacetylene-functionalised anthracene-alt-benzothiadiazole copolymers for application in bulk heterojunction solar cells
Three triisopropylsilylacetylene-functionalised anthracene (TIPSAnt) based polymers were synthesised by copolymerising TIPSAnt with either dithienyl-5,6-difluoro-benzo[c]-[1,2,5]thiadiazole, dithienyl-benzo[c]-[1,2,5]thiadiazole or dibithiophenyl-benzo[c]-[1,2,5]thiadiazole to yield PTATffBT, PTATBT-8 and PTAT2BT-8, respectively. PTAT2BT-8 demonstrated a reduced optical and electrochemical band gap, relative to PTATffBT and PTATBT-8. The HOMO level of PTAT2BT-8 (−5.32 eV) is significantly shallower compared to its counterparts. This can be attributed to increased intramolecular charge transfer along the polymer backbone; a consequence of the incorporation of additional thiophene spacer units. The photovoltaic properties of the polymers were investigated by fabricating bulk heterojunction (BHJ) polymer solar cells using PC70BM as the electron acceptor. PTATffBT displayed limited solubility in common organic solvents and could not be used for the fabrication of photovoltaic cells. Optimised photovoltaic devices fabricated from PTATBT-8 and PTAT2BT-8 demonstrated power conversion efficiencies of 2.36% and 3.15%, respectively. PTAT2BT-8 provided better efficiencies chiefly as a result of better Jsc and FF values
Measurement-induced decoherence and Gaussian smoothing of the Wigner distribution function
We study the problem of measurement-induced decoherence using the phase-space
approach employing the Gaussian-smoothed Wigner distribution function. Our
investigation is based on the notion that measurement-induced decoherence is
represented by the transition from the Wigner distribution to the
Gaussian-smoothed Wigner distribution with the widths of the smoothing function
identified as measurement errors. We also compare the smoothed Wigner
distribution with the corresponding distribution resulting from the classical
analysis. The distributions we computed are the phase-space distributions for
simple one-dimensional dynamical systems such as a particle in a square-well
potential and a particle moving under the influence of a step potential, and
the time-frequency distributions for high-harmonic radiation emitted from an
atom irradiated by short, intense laser pulses.Comment: Accepted in Annals of Physic
Who Watches the Watchmen? An Appraisal of Benchmarks for Multiple Sequence Alignment
Multiple sequence alignment (MSA) is a fundamental and ubiquitous technique
in bioinformatics used to infer related residues among biological sequences.
Thus alignment accuracy is crucial to a vast range of analyses, often in ways
difficult to assess in those analyses. To compare the performance of different
aligners and help detect systematic errors in alignments, a number of
benchmarking strategies have been pursued. Here we present an overview of the
main strategies--based on simulation, consistency, protein structure, and
phylogeny--and discuss their different advantages and associated risks. We
outline a set of desirable characteristics for effective benchmarking, and
evaluate each strategy in light of them. We conclude that there is currently no
universally applicable means of benchmarking MSA, and that developers and users
of alignment tools should base their choice of benchmark depending on the
context of application--with a keen awareness of the assumptions underlying
each benchmarking strategy.Comment: Revie
Greene's Residue Criterion for the Breakup of Invariant Tori of Volume-Preserving Maps
Invariant tori play a fundamental role in the dynamics of symplectic and
volume-preserving maps. Codimension-one tori are particularly important as they
form barriers to transport. Such tori foliate the phase space of integrable,
volume-preserving maps with one action and angles. For the area-preserving
case, Greene's residue criterion is often used to predict the destruction of
tori from the properties of nearby periodic orbits. Even though KAM theory
applies to the three-dimensional case, the robustness of tori in such systems
is still poorly understood. We study a three-dimensional, reversible,
volume-preserving analogue of Chirikov's standard map with one action and two
angles. We investigate the preservation and destruction of tori under
perturbation by computing the "residue" of nearby periodic orbits. We find tori
with Diophantine rotation vectors in the "spiral mean" cubic algebraic field.
The residue is used to generate the critical function of the map and find a
candidate for the most robust torus.Comment: laTeX, 40 pages, 26 figure
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