2,413 research outputs found

    Lessons for Asian Countries from Pension Reforms in Chile

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    Chile's 1981 reform revolutionized pension design and created a system that was lauded and emulated widely. The main feature of the system was the creation of state-mandated, privately managed individual pension capitalization accounts based on contributions of employees. After nearly three decades of experience, there is a reassessment of the extent to which the pension system has achieved its objectives, particularly with respect to coverage and adequacy. In March 2006, the newly elected President Bachelet set up a Presidential Advisory Council on Pension Reform under the chairmanship of Mario Marcel to evaluate the existing pension system. This paper examines the rationale and the nature of the recommendations made by the Council. The analysis focuses on the structure of the proposed new pension system and risk-sharing implications of different pillars of the system, the accessibility of the existing pension system in terms of coverage, particularly for women and self-employed persons, the impact of reform on transaction costs; investment policies and management and their implications for rates of return and financial market development. The implications of the new system on pension design and policy debate in Asian countries are addressed. The paper suggests that must imbibe lessons from countries such as Chile and urgently undertake the task of constructing sustainable, robust and adequate pension systems and social safety nets.Chile, Asia, Pension Reform

    Limit theorems for functions of marginal quantiles

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    Multivariate distributions are explored using the joint distributions of marginal sample quantiles. Limit theory for the mean of a function of order statistics is presented. The results include a multivariate central limit theorem and a strong law of large numbers. A result similar to Bahadur's representation of quantiles is established for the mean of a function of the marginal quantiles. In particular, it is shown that n(1ni=1nϕ(Xn:i(1),...,Xn:i(d))γˉ)=1ni=1nZn,i+oP(1)\sqrt{n}\Biggl(\frac{1}{n}\sum_{i=1}^n\phi\bigl(X_{n:i}^{(1)},...,X_{n:i}^{(d)}\bigr)-\bar{\gamma}\Biggr)=\frac{1}{\sqrt{n}}\sum_{i=1}^nZ_{n,i}+\mathrm{o}_P(1) as nn\rightarrow\infty, where γˉ\bar{\gamma} is a constant and Zn,iZ_{n,i} are i.i.d. random variables for each nn. This leads to the central limit theorem. Weak convergence to a Gaussian process using equicontinuity of functions is indicated. The results are established under very general conditions. These conditions are shown to be satisfied in many commonly occurring situations.Comment: Published in at http://dx.doi.org/10.3150/10-BEJ287 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    On Modeling Bivariate Left Censored Data using Reversed Hazard Rates

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    When the observations are not quantified and are known to be less than a threshold value, the concept of left censoring needs to be included in the analysis of such datasets. In many real multi component lifetime systems left censored data is very common. The usual assumption that components which are part of a system, work independently seems not appropriate in a number of applications. For instance it is more realistic to acknowledge that the working status of a component affects the remaining components. When you have left-censored data, it is more meaningful to use the reversed hazard rate, proposed as a dual to the hazard rate. In this paper, we propose a model for left-censored bivariate data incorporating the dependence enjoyed among the components, based on a dynamic bivariate vector reversed hazard rate proposed in Gurler (1996). The properties of the proposed model is studied. The maximum likelihood method of estimation is shown to work well for moderately large samples. The Bayesian approach to the estimation of parameters is also presented. The complexity of the likelihood function is handled through the Metropolis - Hastings algorithm. This is executed with the MH adaptive package in r. Different interval estimation techniques of the parameters are also considered. Applications of this model is demonstrated by illustrating the usefulness of the model in analyzing real data

    On a Model for Bivariate Left Censored Data

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    The lifetimes of subjects which are left-censored lie below a threshold value or a limit of detection. A popular tool used to handle left-censored data is the reversed hazard rate. In this work, we study the properties and develop characterizations of a class of distributions based on proportional reversed hazard rates used for analyzing left censored data. These characterizations are applied to simulate samples as well as analyze real data using distributions belonging to this class.Comment: 16 pages, 4 figure

    Further Results on the Bivariate Semi-parametric Singular Family of Distributions

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    General classes of bivariate distributions are well studied in literature. Most of these classes are proposed via a copula formulation or extensions of some characterisation properties in the univariate case. In Kundu(2022) we see one such semi-parametric family useful to model bivariate data with ties. This model is a general semi-parametric model with a baseline. In this paper we present a characterisation property of this class of distributions in terms of a functional equation. The general solution to this equation is explored. Necessary and sufficient conditions under which the solution becomes a bivariate distribution is investigated

    Market Structure and Challenges for Annuities in India

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    India will need to develop a robust annuity market if it is to enable its rapidly aging population to address longevity risk. As the fraction aged triples by 2050, driving a huge potential demand for annuity-type products that will need to be matched by responses from annuity providers. Developing a deeper and broader market for annuities will require disaggregated morbidity and mortality databases for better price discovery; supply of financial instruments enabling better matching of assets and long-term liabilities; innovations in annuity products and distribution channels; greater financial literacy, and more robust regulation

    Particle Motion and Scalar Field Propagation in Myers-Perry Black Hole Spacetimes in All Dimensions

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    We study separability of the Hamilton-Jacobi and massive Klein-Gordon equations in the general Myers-Perry black hole background in all dimensions. Complete separation of both equations is carried out in cases when there are two sets of equal black hole rotation parameters, which significantly enlarges the rotational symmetry group. We explicitly construct a nontrivial irreducible Killing tensor associated with the enlarged symmetry group which permits separation. We also derive first-order equations of motion for particles in these backgrounds and examine some of their properties.Comment: 16 pages, LaTeX2

    NMR analysis of the dynamic exchange of the NS2B cofactor between open and closed conformations of the West Nile Virus NS2B-NS3 protease

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    BACKGROUND The two-component NS2B-NS3 proteases of West Nile and dengue viruses are essential for viral replication and established targets for drug development. In all crystal structures of the proteases to date, the NS2B cofactor is located far from the substrate binding site (open conformation) in the absence of inhibitor and lining the substrate binding site (closed conformation) in the presence of an inhibitor. METHODS In this work, nuclear magnetic resonance (NMR) spectroscopy of isotope and spin-labeled samples of the West Nile virus protease was used to investigate the occurrence of equilibria between open and closed conformations in solution. FINDINGS In solution, the closed form of the West Nile virus protease is the predominant conformation irrespective of the presence or absence of inhibitors. Nonetheless, dissociation of the C-terminal part of the NS2B cofactor from the NS3 protease (open conformation) occurs in both the presence and the absence of inhibitors. Low-molecular-weight inhibitors can shift the conformational exchange equilibria so that over 90% of the West Nile virus protease molecules assume the closed conformation. The West Nile virus protease differs from the dengue virus protease, where the open conformation is the predominant form in the absence of inhibitors. CONCLUSION Partial dissociation of NS2B from NS3 has implications for the way in which the NS3 protease can be positioned with respect to the host cell membrane when NS2B is membrane associated via N- and C-terminal segments present in the polyprotein. In the case of the West Nile virus protease, discovery of low-molecular-weight inhibitors that act by breaking the association of the NS2B cofactor with the NS3 protease is impeded by the natural affinity of the cofactor to the NS3 protease. The same strategy can be more successful in the case of the dengue virus NS2B-NS3 protease.The project was funded by the Australian Research Council (http://www.arc.gov.au), grant DP0877540
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