Ageing in Mortal Superdiffusive L\'evy Walkers

A growing body of literature examines the effects of superdiffusive subballistic movement pre-measurement (ageing or time lag) on observations arising from single-particle tracking. A neglected aspect is the finite lifetime of these L\'{e}vy walkers, be they proteins, cells or larger structures. We examine the effects of ageing on the motility of mortal walkers, and discuss the means by which permanent stopping of walkers may be categorised as arising from `natural' death or experimental artefacts such as low photostability or radiation damage. This is done by comparison of the walkers' mean squared displacement (MSD) with the front velocity of propagation of a group of walkers, which is found to be invariant under time lags. For any running time distribution of a mortal random walker, the MSD is tempered by the stopping rate $\theta$. This provides a physical interpretation for truncated heavy-tailed diffusion processes and serves as a tool by which to better classify the underlying running time distributions of random walkers. Tempering of aged MSDs raises the issue of misinterpreting superdiffusive motion which appears Brownian or subdiffusive over certain time scales

An investigation of the marine boundary layer during cold air outbreak

Methods for use in the remote estimation of ocean surface sensible and latent heat fluxes were developed and evaluated. Three different techniques were developed for determining these fluxes. These methods are: (1) Obtaining surface sensible and latent heat fluxes from satellite measurements; (2)Obtaining surface sensible and latent heat fluxes from an MABL model; (3) A method using horizontal transfer coefficients. These techniques are not very sensitive to errors in the data and therefore appear to hold promise of producing useful answers. Questions remain about how closely the structure of the real atmosphere agrees with the assumptions made for each of these techniques, and, therefore about how well these techniques can perform in actual use. The value of these techniques is that they promise to provide methods for the determination of fluxes over regions where very few traditional measurement exist

Turbulent statistics in the vicinity of an SST front: A north wind case, FASINEX February 16, 1986

The technique of boxcar variances and covariances is used to examine NCAR Electra data from FASINEX (Frontal Air-Sea Interaction EXperiment). This technique was developed to examine changes in turbulent fluxes near a sea surface temperature (SST) front. The results demonstrate the influence of the SST front on the MABL (Marine Atmospheric Boundary Layer). Data shown are for February 16, 1986, when the winds blew from over cold water to warm. The front directly produced horizontal variability in the turbulence. The front also induced a secondary circulation which further modified the turbulence

Climate Change, Total Factor Productivity, and the Tanzanian Economy: A Computable General Equilibrium Analysis

This paper analyzes the economic impacts of climate change-induced adjustments on the performance of the Tanzanian economy, using a countrywide CGE (computable general equilibrium) model. The general equilibrium framework enables comparison of the effects of climate change to the overall growth of the economy because responsiveness to shocks is likely to depend on the macroeconomic structure of the economy. Effect of overall climate change on agricultural productivity is projected to be relatively limited until approximately 2030 and become worse thereafter. Our simulation results indicate that, despite the projected reduction in agricultural productivity, the negative impacts can potentially be quite limited. This is because the time scales involved and the low starting point of the economy leave ample time for factor substitutability (i.e., replacing reduced land productivity with increased use of capital and labor) and increased overall productivity. This indicates that policies that give farmers opportunity to invest in autonomous climate adaptation, as well as policies that improve the overall performance of the economy, can be as important for reducing the impacts of climate change in the economy as direct government policies for climate adaptation. The study results can inform policymakers when choosing between direct climate-change adaptation policies or measures aimed at strengthening the fundamentals of the economy, as ways of insulating against external shocks.climate change, agriculture, total factor productivity, Tanzania, CGE model

Optimal Tax and Expenditure Policy in the Presence of Migration - Are Credit Restrictions Important?

This paper concerns optimal income taxation in the presence of emigration. The basic model is a two-period model where all agents are identical and live in the home country in the first period of life, but where some emigrate at the end of the first period. It is shown that with a binding credit restriction, the government will tax labor income in the first period at a higher rate than otherwise, whereas the labor income tax in the second period is unaffected by emigration. With heterogenous agents, the labor income tax in period two will be affected by emigration.optimal taxation; labor mobility; intertemporal consumer choice

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