Topographic mapping of retinal function with the SLO-mfERG under simultaneous control of fixation in Best's disease

Purpose: To introduce the scanning laser ophthalmoscope-evoked mfERG (SLO-mfERG) as a new method to measure focal retinal function. Methods: Sixty-two healthy individuals and 12 patients with Best's disease were examined. mfERGs were recorded using a scanning laser ophthalmoscope as a stimulator and trigger device (He-Neon 632.8 nm) as well as a fundus-monitoring system (infrared 730 nm). Results: Amplitudes in the central concentric area were found to be significantly lower in patients with Best's disease than in healthy controls, while no significant differences were found for the more peripheral areas. Conclusion: SLO-mfERG is a reliable new technique for topographic mapping of retinal function under simultaneous control of fixation

Upgrading investment regulations in second pillar pension systems : a proposal for Colombia

The passivity of the demand for pension products is one of the striking features of mandatory pension systems. Consequently, the provision of multiple investment alternatives to households (multifund schemes) does not ensure that contributions are invested efficiently. In addition, despite the theoretical findings that short term return maximization is not conductive to long-term return maximization, the regulatory framework of pension fund management companies puts excessive emphasis on short-term maximization. Therefore, it is not obvious that typical regulatory framework of pension funds is conductive to optimal pensions. By establishing a set of default options on investment portfolios, this paper proposes a mechanism to align the incentives of the pension fund management companies with the long-term objectives of the contributors. The paper provides a methodology, which is subsequently applied to Colombia.Debt Markets,Emerging Markets,Financial Literacy,Mutual Funds,Investment and Investment Climate

A summary and update of developing annuities markets : the experience of Chile

The rapid growth of the market for retirement products in Chile has its origins in the pension reform that was implemented in 1981. But the successful development of an active annuity market also reflects many other factors. This paper summarizes and updates an earlier longer study on the development of the Chilean annuity market. The update focuses on the numerous changes that were introduced in 2008. The most striking aspect of the Chilean experience is the very high rate of annuitization. This has been linked to the restrictions that have been applied to lump-sum withdrawals, the offer of inflation-protected annuities, and the robust prudential regulation of providers. But the level of annuitization has also been supported by the annuitization incentives provided to early retirees and the influence of brokers and sales agents. The recent regulatory changes have weakened the impact of the last two factors, while strengthening the demand for annuities at normal retirement.Debt Markets,Pensions&Retirement Systems,Insurance&Risk Mitigation,Emerging Markets,Non Bank Financial Institutions

Challenges of the mandatory funded pension system in the Russian Federation

The overwhelming number of contributors that have been allocated into the default option is one of the main characteristics of the Russian second pillar. This finding confirms that the level of financial literacy for most of the participants is not sufficient to make informed portfolio selections. The authors argue that the current system is perfectly consistent with a solid second pillar, but the authorities should focus their attention in the strategic asset allocation of pension funds. Since in the short and medium term it is unlikely to see improvements in financial literacy of individuals that may overcome the complexity of these decisions, the authorities can play an important role in designing default investment portfolios that can be aligned with expected replacement rates for the contributors. The current investment regulation of the default option induces investment in inefficient portfolios that are unlikely to bring returns above inflation, and probably will result in very low replacement rates for contributors. Further liberalization of the investments of the pension portfolio; improvements in the governance and supervision of the pension system; and greater certainty about the ownership of the funds are necessary steps to complete the pension reform launched in 2002.Debt Markets,Financial Literacy,Emerging Markets,Pensions&Retirement Systems,Access to Finance

One-way quantum computation with four-dimensional photonic qudits

We consider the possibility of performing linear optical quantum computation making use of extra photonic degrees of freedom. In particular we focus on the case where we use photons as quadbits. The basic 2-quadbit cluster state is a hyper-entangled state across polarization and two spatial mode degrees of freedom. We examine the non-deterministic methods whereby such states can be created from single photons and/or Bell pairs, and then give some mechanisms for performing higher-dimensional fusion gates.Comment: 10 figures (typos are corrected

Error distributions on large entangled states with non-Markovian dynamics

We investigate the distribution of errors on a computationally useful entangled state generated via the repeated emission from an emitter undergoing strongly non-Markovian evolution. For emitter-environment coupling of pure-dephasing form, we show that the probability that a particular patten of errors occurs has a bound of Markovian form, and thus accuracy threshold theorems based on Markovian models should be just as effective. This is the case, for example, for a charged quantum dot emitter in a moderate to strong magnetic field. Beyond the pure-dephasing assumption, though complicated error structures can arise, they can still be qualitatively bounded by a Markovian error model.Comment: Close to published versio

Final-State Interaction as the Origin of the Cronin Effect

Instead of adhering to the usual explanation of the Cronin effect in terms of the broadening of the parton transverse momentum in the initial state, we show that the enhancement of hadron production at moderate $p_T$ in d+Au collisions is due to the recombination of soft and shower partons in the final state. Such a mechanism can readily explain the decrease of the Cronin effect with increasing rapidity. Furthermore, the effect should be larger for protons than for pions.Comment: 4 RevTeX pages including 3 figures and 1 table; Some notational changes and a corrected referenc

Production of strange particles at intermediate pT at RHIC

The recombination model is applied to the production of $K, \phi, \Lambda$ and $\Omega$ at all $p_T$ in central Au+Au collisions. The thermal-shower component of the recombination is found to be important for $K$ and $\Lambda$, but only in a minor way for $\phi$ and $\Omega$ in the intermediate to high $p_T$ region. The normalization and inverse slope of the thermal partons in the strange sector are determined by fitting the low-$p_T$ data. At higher $p_T$ the data of $K, \phi, \Lambda$ and $\Omega$ in the log scale are all well reproduced in our study that extends the thermal contribution and includes the shower contribution. The calculated result on the $\Lambda/K$ ratio rises to a maximum of around 2 at $p_T\approx 4$ GeV/c, arching over the data in linear scale. The production of $\phi$ and $\Omega$ are shown to arise mainly from the recombination of thermal partons, thus exhibiting exponential $p_T$ dependences in agreement with the data. Their ratio, $R_{\Omega/\phi}$, rises linearly to $p_T\approx 4$ GeV/c and develops a maximum at $p_T\approx 5.5$ GeV/c. It is argued that the $p_T$ spectra of $\phi$ and $\Omega$ reveal directly the partonic nature of the thermal source that characterizes quark-gluon plasma. Comments are made on the $\Omega$ puzzle due to the simultaneous observation of both the exponential behavior of the $\Omega$ spectrum in $p_T$ and the existence of low-$p_T$ particles associated with $\Omega$ as trigger.Comment: Revised manuscript with new figure