580 research outputs found
Innovative Approaches to Managing Longevity Risk in Asia: Lessons from the West
This paper discusses what is longevity risk, why it is important, approaches used by the West to manage longevity risk and what lessons can be learnt by Asian countries from the experiences of the West. Increasing and uncertain longevity has emerged as a key risk affecting individuals, pension plans, insurers and governments in both the developed and emerging world. I discuss progress in the field of longevity modelling and the merits as well as drawbacks of these models. In Western countries, attempts have been made by capital market and governments to deal with longevity risk, but the availability of solutions remain limited. Further developments should focus on creating a set of instruments that are effective, economically affordable, and transparently priced. It is important to understand, measure, and manage longevity risk. Moreover, further pension reforms are needed to address the root of the problem. For Asian countries, the experience of the West provides ample guidance in formulating their pension plans and promoting capital market developments to avoid the same predicament the West is now struggling with. Simple cost-effective solutions linking retirement ages to longevity, efficiently engaging women and older workers in the work force for longer, education and technology driven flexible work practices, along with preventing productive human capital outflows ought to be considered seriously in Asia
The proapoptotic dp5 gene is a direct target of the MLK-JNK-c-Jun pathway in sympathetic neurons
The death of sympathetic neurons after nerve growth factor (NGF) withdrawal requires de novo gene expression. Dp5 was one of the first NGF withdrawal-induced genes to be identified and it encodes a proapoptotic BH3-only member of the Bcl-2 family. To study how dp5 transcription is regulated by NGF withdrawal we cloned the regulatory regions of the rat dp5 gene and constructed a series of dp5-luciferase reporter plasmids. In microinjection experiments with sympathetic neurons we found that three regions of dp5 contribute to its induction after NGF withdrawal: the promoter, a conserved region in the single intron, and sequences in the 3′ untranslated region of the dp5 mRNA. A construct containing all three regions is efficiently activated by NGF withdrawal and, like the endogenous dp5, its induction requires mixed-lineage kinase (MLK) and c-Jun N-terminal kinase (JNK) activity. JNKs phosphorylate the AP-1 transcription factor c-Jun, and thereby increase its activity. We identified a conserved ATF site in the dp5 promoter that binds c-Jun and ATF2, which is critical for dp5 promoter induction after NGF withdrawal. These results suggest that part of the mechanism by which the MLK-JNK-c-Jun pathway promotes neuronal apoptosis is by activating the transcription of the dp5 gene
The acceptability and feasibility of a brief psychosocial intervention to reduce blood-borne virus risk behaviours among people who inject drugs: A randomised control feasibility trial of a psychosocial intervention (the PROTECT study) versus treatment as usual
Background: While opiate substitution therapy and injecting equipment provision (IEP) have reduced blood-borne viruses (BBV) among people who inject drugs (PWID), some PWID continue to share injecting equipment and acquire BBV. Psychosocial interventions that address risk behaviours could reduce BBV transmission among PWID.Methods: A pragmatic, two-armed randomised controlled, open feasibility study of PWID attending drug treatment or IEP in four UK regions. Ninety-nine PWID were randomly allocated to receive a three-session manualised psychosocial group intervention and BBV transmission information booklet plus treatment as usual (TAU) (n = 52) or information booklet plus TAU (n = 47). The intervention was developed from evidence-based literature, qualitative interviews with PWID, key stakeholder consultations, and expert opinion. Recruitment rates, retention in treatment, follow-up completion rates and health economic data completion measured feasibility.Results: Fifty-six percent (99/176) of eligible PWID were recruited. More participants attended at least one intervention session in London (10/16; 63%) and North Wales (7/13; 54%) than in Glasgow (3/12; 25%) and York (0/11). Participants who attended no sessions (n = 32) compared to those attending at least one (n = 20) session were more likely to be homeless (56 vs 25%, p = 0.044), injected drugs for a greater number of days (median 25 vs 6.5, p = 0.019) and used a greater number of needles from an IEP in the last month (median 31 vs 20, p = 0.056). No adverse events were reported. 45.5% (45/99) were followed up 1 month post-intervention. Feedback forms confirmed that the intervention was acceptable to both intervention facilitators and participants who attended it. Follow-up attendance was associated with fewer days of injecting in the last month (median 14 vs 27, p = 0.030) and fewer injections of cocaine (13 vs 30%, p = 0.063). Analysis of the questionnaires identified several service use questionnaire categories that could be excluded from the assessment battery in a full-randomised controlled trial.Conclusions: Findings should be interpreted with caution due to small sample sizes. A future definitive RCT of the psychosocial intervention is not feasible. The complex needs of some PWID may have limited their engagement in the intervention. More flexible delivery methods may have greater reach
Search for Higgs Bosons in e+e- Collisions at 183 GeV
The data collected by the OPAL experiment at sqrts=183 GeV were used to
search for Higgs bosons which are predicted by the Standard Model and various
extensions, such as general models with two Higgs field doublets and the
Minimal Supersymmetric Standard Model (MSSM). The data correspond to an
integrated luminosity of approximately 54pb-1. None of the searches for neutral
and charged Higgs bosons have revealed an excess of events beyond the expected
background. This negative outcome, in combination with similar results from
searches at lower energies, leads to new limits for the Higgs boson masses and
other model parameters. In particular, the 95% confidence level lower limit for
the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons
can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA >
72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and
soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for
minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM
parameter space are also considered.Comment: 49 pages. LaTeX, including 33 eps figures, submitted to European
Physical Journal
A Measurement of the Product Branching Ratio f(b->Lambda_b).BR(Lambda_b->Lambda X) in Z0 Decays
The product branching ratio, f(b->Lambda_b).BR(Lambda_b->Lambda X), where
Lambda_b denotes any weakly-decaying b-baryon, has been measured using the OPAL
detector at LEP. Lambda_b are selected by the presence of energetic Lambda
particles in bottom events tagged by the presence of displaced secondary
vertices. A fit to the momenta of the Lambda particles separates signal from B
meson and fragmentation backgrounds. The measured product branching ratio is
f(b->Lambda_b).BR(Lambda_b->Lambda X) = (2.67+-0.38(stat)+0.67-0.60(sys))%
Combined with a previous OPAL measurement, one obtains
f(b->Lambda_b).BR(Lambda_b->Lambda X) = (3.50+-0.32(stat)+-0.35(sys))%.Comment: 16 pages, LaTeX, 3 eps figs included, submitted to the European
Physical Journal
A measurement of the tau mass and the first CPT test with tau leptons
We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV
using tau pairs from Z0 decays. To test CPT invariance we compare the masses of
the positively and negatively charged tau leptons. The relative mass difference
is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.
A Measurement of Rb using a Double Tagging Method
The fraction of Z to bbbar events in hadronic Z decays has been measured by
the OPAL experiment using the data collected at LEP between 1992 and 1995. The
Z to bbbar decays were tagged using displaced secondary vertices, and high
momentum electrons and muons. Systematic uncertainties were reduced by
measuring the b-tagging efficiency using a double tagging technique. Efficiency
correlations between opposite hemispheres of an event are small, and are well
understood through comparisons between real and simulated data samples. A value
of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is
statistical and the second systematic. The uncertainty on Rc, the fraction of Z
to ccbar events in hadronic Z decays, is not included in the errors. The
dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the
deviation of Rc from the value 0.172 predicted by the Standard Model. The
result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the
Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European
Physical Journal
First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons
We report the first observation of Z/gamma* production in Compton scattering
of quasi-real photons. This is a subprocess of the reaction e+e- to
e+e-Z/gamma*, where one of the final state electrons is undetected.
Approximately 55 pb-1 of data collected in the year 1997 at an e+e-
centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been
analysed. The Z/gamma* from Compton scattering has been detected in the
hadronic decay channel. Within well defined kinematic bounds, we measure the
product of cross-section and Z/gamma* branching ratio to hadrons to be
(0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV,
dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60
GeV, dominated by (e)egamma* production, this product is found to be
(4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo
event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters
Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays
The lifetime and oscillation frequency of the B0 meson has been measured
using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP.
The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the
production flavour of the B0 mesons was determined using a combination of tags
from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d
= 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first
error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.
Measurement of the Michel Parameters in Leptonic Tau Decays
The Michel parameters of the leptonic tau decays are measured using the OPAL
detector at LEP. The Michel parameters are extracted from the energy spectra of
the charged decay leptons and from their energy-energy correlations. A new
method involving a global likelihood fit of Monte Carlo generated events with
complete detector simulation and background treatment has been applied to the
data recorded at center-of-mass energies close to sqrt(s) = M(Z) corresponding
to an integrated luminosity of 155 pb-1 during the years 1990 to 1995. If e-mu
universality is assumed and inferring the tau polarization from neutral current
data, the measured Michel parameters are extracted. Limits on non-standard
coupling constants and on the masses of new gauge bosons are obtained. The
results are in agreement with the V-A prediction of the Standard Model.Comment: 32 pages, LaTeX, 9 eps figures included, submitted to the European
Physical Journal
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