Empowering statistical methods for cellular and molecular biologists.

We provide guidelines for using statistical methods to analyze the types of experiments reported in cellular and molecular biology journals such as Molecular Biology of the Cell. Our aim is to help experimentalists use these methods skillfully, avoid mistakes, and extract the maximum amount of information from their laboratory work. We focus on comparing the average values of control and experimental samples. A Supplemental Tutorial provides examples of how to analyze experimental data using R software

Rescue litter flotation assembly Patent

Development and characteristics of rescue litter with inflatable flotation device for water rescue applicatio

Flow in tee junctions

Imperial Users onl

The effects of annuities, bequests, and aging in an overlapping generations model of endogenous growth.

In this paper, we examine the effects of introducing actuarially fair annuity markets into an overlapping generations model of endogenous growth. We find the complete annuitization of agents' wealth is not, in general, dynamically optimal; that the degree of annuitization that is dynamically optimal depends nonmonotonically on the expected length of retirement and on the pay-as-you-go social security tax rate. We find that the government has an incentive to restrict the availability of actuarially fair annuities contracts, and that it can often move the economy from a pay-as-you-go to a fully-funded social security system via voluntary contributions to a government sponsored, actuarially fair pension today accompanied by reductions in social security taxes tomorrow.Wealth ; Old age

Dependent children and aged parents: funding education and social security in an aging economy

In the last few decades in the United States birth rates have declined and longevity has risen while productivity growth has slowed. Given such changes, the increasing burden of funding programs for the elderly is likely to shift resources away from the young and toward the elderly. This paper uses an overlapping generations framework to examine the effects of tax policies on an aging economy. We find that if the quality of the education system is sufficiently high then shifting tax resources away from social security and toward education is both growth and welfare enhancing.Education ; Social security

The effects of aging and myopia on the pay-as-you-go social security systems of the G7

The Social Security systems of the G7 countries were established in an era when populations were young and the number of contributors far outweighed the number of beneficiaries. Now, for each beneficiary there are fewer contributors, and this downward trend is projected to accelerate. To evaluate the prospects for these economies we develop an overlapping generations model in which growth is endogenously fueled by individuals' investments in physical and human capital and by the government's investment in human capital via public education expenditures. We analyze individuals' behavior when their expectations over their length of life are rational and adaptive (myopic). We examine for each of the economies and for each of the expectation assumptions whether policies exist that can offset the effects of aging, should they be adverse. Further, we examine how policies aimed at a specific target group affect the welfare of the economy as a whole.Social security ; Group of Seven countries

Aging, myopia and the pay-as-you-go public pension systems of the G7: a bright future?

The public pension systems of the G7 countries were established in an era when the number of contributors far outweighed the number of beneficiaries. Now, for each beneficiary there are fewer contributors, and this trend is projected to accelerate. To evaluate the prospects for these economies we develop an overlapping generations model where growth is endogenously fueled by investments in physical and human capital. We analyze individuals' behavior when their expectations over their length of life are rational or myopic and examine whether policies exist that can offset the effects of aging, should they be adverse. We find that while perfectly anticipated aging is welfare improving and does not threaten the solvency of public pension systems, myopia worsens welfare, puts pension systems at risk, and cannot be easily remedied by public policy.Social security

Reforming Social Security: a welfare analysis

Social security ; Welfare

A simple model of international capital flows, exchange rate risk, and portfolio choice

This paper examines international capital flows in the context of a simple Diamond-Dybvig model in which there are neither moral hazard nor adverse selection problems, thus isolating exchange rate risk as the propagator of capital flows. The model shows that adverse changes in exchange rate expectations can result in "hot money" flows even when a bank's balance sheet is perfectly transparent and its assets have a positive net present value in local currency terms. The model also indicates that foreign deposit guarantees even in the absence of a change in the bank's portfolio can increase the chance of bank runs.Capital movements ; Foreign exchange

Off-fault tensile cracks: A link between geological fault observations, lab experiments, and dynamic rupture models

We examine the local nature of the dynamic stress field in the vicinity of the tip of a semi-infinite sub-Rayleigh (slower than the Rayleigh wave speed, c_R) mode II crack with a velocity-weakening cohesive zone. We constrain the model using results from dynamic photoelastic experiments, in which shear ruptures were nucleated spontaneously in Homalite-100 plates along a bonded, precut, and inclined interface subject to a far-field uniaxial prestress. During the experiments, tensile cracks grew periodically along one side of the shear rupture interface at a roughly constant angle relative to the shear rupture interface. The occurrence and inclination of the tensile cracks are explained by our analytical model. With slight modifications, the model can be scaled to natural faults, providing diagnostic criteria for interpreting velocity, directivity, and static prestress state associated with past earthquakes on exhumed faults. Indirectly, this method also allows one to constrain the velocity-weakening nature of natural ruptures, providing an important link between field geology, laboratory experiments, and seismology