678 research outputs found
Physics prospects of UV-filtered overlap quarks
Some key features of the overlap operator with a UV-filtered Wilson kernel
are discussed. The first part concerns spectral properties of the underlying
shifted hermitean Wilson operator and the relation to the observed speedup of
the overlap construction. Next, the localization of the filtered overlap and
its axial-vector renormalization constant are discussed. Finally, results of an
exploratory scaling study for and are presented.Comment: Talk given at Workshop on Computational Hadron Physics, Nicosia,
Cyprus, 14-17 Sep 200
Prudent Investors: The Asset Allocation of Public Pension Plans
After 2000, the vast majority of defined benefit (DB) pension plans encountered a decrease in their funding ratios, largely due to a drop in asset prices. It is possible that public sector pension plans may have acted imprudently by chasing returns, once they encountered underfunding. We identify four indicators for DB plans’ imprudent investment behavior: no portfolio rebalancing, employer conflicts of interest, trustee conflicts of interest, and failure to implement best investment practices. To see if public sector pension plans rebalance their portfolios, we use data from the Federal Reserve’s Flow of Funds, dating from 1952 to 2007. To test for the remaining three hypotheses, we use data from the Census’ State and Local Government Employee Retirement Systems data base, where consistent data for state and local government plans are available from 1993 to 2005. Our results suggest that there is no evidence that public sector plans systematically engaged in imprudent investment behavior and that this did not systematically differ after 2000 from the earlier period.
The Interplay between Labor and Financial Markets: What are the Implications for Defined Contribution Accounts?
The relationship between earnings, savings and retirement is well-known; however the linkage between labor market outcomes and financial market performance is generally unacknowledged. This Working Paper examines the implications of the link between labor markets and financial markets for workers who save money in individual retirement accounts. Specifically, differences in labor market outcomes across groups may imply differences in the timing of investments, which may reduce savings over time for these groups compared to their counterparts. Using monthly data from the Current Population Survey (1979-2002) we generate hypothetical investment portfolios using stock and bond indices. We exploit differences across demographic groups in unemployment and wage growth, and use these differences to examine each group’s investment outcomes. We then disaggregate the total effects into short-term and long-term components. We find some evidence of short-term market timing effects on investment, but we find much larger long-term effects for some groups. Our findings suggest that, for many people, the retirement savings losses associated with the timing of markets are similar to the costs of annuitizing savings upon retirement. The differences are especially pronounced by education and sex.Individual accounts, retirement savings, earnings volatility
Easy Money? Health and 401(k) Loans
Rising health care costs and declining personal savings rates are nearly synonymous with household medical debt. For some, defined contribution (DC) retirement savings plans provide a ready source of funds to meet these medical debts. We examine whether health status and health insurance coverage predict the likelihood of having a DC loan using data from the Federal Reserve’s triennial Survey of Consumer Finances from 1989 to 2007. We find that poor health raises the likelihood that a household will borrow from their DC plans, even controlling for other forms of debt, access to credit, and whether households are covered by health insurance. Our estimates of the amount of the DC loan, taking selection effects into account, indicates that DC loan amounts are also influenced by health status; those with poor health borrow more from their DC plans. Apart from health status, once a household decides to borrow from their retirement funds, race and education also influence how much to borrow. We argue that public policy can improve the long-term financial retirement security of households by offering more opportunities to save for medical emergencies, while cautiously maintaining the opportunity to borrow from DC plans.��Defined contribution retirement savings plans; pension debt; health insurance coverage; health status
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Radio Frequency CMOS Chem-bio Viscosity Sensors based on Dielectric Spectroscopy
This paper presents a CMOS Radio frequency dielectric sensor platform for the detection of relative viscosity changes in a fluid sample. The operating frequency of the sensor is 12.28 GHz. This frequency range has been chosen for high signal to noise ratio and also to avoid other low frequency dispersion mechanisms for future lab on chip applications. The sensor chip has been fabricated in 250 nm BiCMOS technology of IHP. The measurements conducted to show the relative viscosity variation detection capability of the sensor chip, were based on mixtures of glycerol and water as well as glycerol and organic alcohol. The detection limit of viscosity is dependent on the permittivity contrast of the sample constituent. Therefore, it is also shown the choice of frequency inherently aids in the permittivity contrast of the sample constituents
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Control of etch pit formation for epitaxial growth of graphene on germanium
Graphene epitaxy on germanium by chemical vapor deposition is a promising approach to integrate graphene into microelectronics, but the synthesis is still accompanied by several challenges such as the high process temperature, the reproducibility of growth, and the formation of etch pits during the process. We show that the substrate cleaning by preannealing in molecular hydrogen, which is crucial to successful and reproducible graphene growth, requires a high temperature and dose. During both substrate cleaning and graphene growth, etch pits can develop under certain conditions and disrupt the synthesis process. We explain the mechanisms how these etch pits may form by preferential evaporation of substrate, how substrate topography is related to the state of the cleaning process, and how etch pit formation during graphene growth can be controlled by choice of a sufficiently high precursor flow. Our study explains how graphene can be grown reliably on germanium at high temperature and thereby lays the foundation for further optimization of the growth process. © 2019 Author(s)
RRAM Reliability/Performance Characterization through Array Architectures Investigations
The reliability and performance characterization of each non-volatile memory technology requires the thorough investigation of dedicated array test structures that mimic the real operations of a fully functional integrated product. This makes no exception also for emerging non-volatile memories like the Resistive Random Access Memory (RRAM) concept. An extensive electrical characterization activity performed on test vehicles manufactured in a CMOS backend-of-line process allowed the first glance estimation of operation modes and reliability threats typical of this technology. In this paper, it is provided a review of the most important issues like forming instabilities, optimal set/reset operation finding, and read disturb to provide a guideline either for a further technology optimization or an efficient algorithms co-design to handle these reliability/performance threats
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In-Vitro Classification of Saliva Samples of COPD Patients and Healthy Controls Using Machine Learning Tools
Chronic Obstructive Pulmonary Disease (COPD) is a life-threatening lung disease and a major cause of morbidity and mortality worldwide. Although a curative therapy has yet to be found, permanent monitoring of biomarkers that refiect the disease progression plays a pivotal role for the effective management of COPD. The accurate examination of respiratory tract fiuids like saliva is a promising approach for staging disease and predicting its upcoming exacerbations in a Point-of-Care (PoC) environment. However, the concurrent consideration of patients' demographic and medical parameters is necessary for achieving accurate outcomes. Therefore, Machine Learning (ML) tools can play an important role for analyzing patient data and providing comprehensive results for the recognition of COPD in a PoC setting. As a result, the objective of this research work was to implement ML tools on data acquired from characterizing saliva samples of COPD patients and healthy controls as well as their demographic information for PoC recognition of the disease. For this purpose, a permittivity biosensor was used to characterize dielectric properties of saliva samples and, subsequently, ML tools were applied on the acquired data for classification. The XGBoost gradient boosting algorithm provided a high classification accuracy and sensitivity of 91.25% and 100%, respectively, making it a promising model for COPD evaluation. Integration of this model on a neuromorphic chip, in the future, will enable the real-time assessment of COPD in PoC, with low cost, low energy consumption, and high patient privacy. In addition, constant monitoring of COPD in a near-patient setup will enable the better management of the disease exacerbations
The meson at the physical point with Wilson twisted mass fermions
We present results for the eta prime meson and the topological susceptibility
in two flavour lattice QCD. The results are obtained using Wilson twisted mass
fermions at maximal twist with pion masses ranging from 340 MeV down to the
physical point. A comparison to literature values is performed giving a handle
on discretisation effects.Comment: Lattice 2017 proceeding contributio
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