Gundlach oscillations and Coulomb blockade of Co nano-islands on MgO/Mo(100) investigated by scanning tunneling spectroscopy at 300 K

Ultrathin MgO films on Mo(100) with a thickness up to 12 ML are studied by scanning tunneling microscopy and spectroscopy at room temperature. The spatial variation of the work function within the MgO film is mapped by field emission resonance states (Gundlach oscillations) using dz/dU spectroscopy. We found circular spots with significantly reduced work function (DeltaPhi=0.6 eV), which are assigned to charged defects within the MgO film. On top of the MgO films, small Co cluster are deposited with an average contact area of 4 nm^2. These islands exhibit Coulomb oscillations in dI/dU spectra at room temperature. Good agreement with orthodox theory is achieved showing variations of the background charge Q_0 for islands at different positions, which are in accordance with the work function differences determined by the Gundlach oscillations.Comment: 7 pages, 3 figure

Seven zero nine zero computer program for determination of precision lattice constants

Computer program for calculation of lattice parameters for cubic, tetragonal, and hexagonal crystals - magnesium oxide and aluminum oxid

Is Health Insurance Affordable for the Uninsured?

In this paper, we investigate the meaning of affordability' in the context of health insurance. Assessing the relationship between the affordability of coverage and the large number of uninsured in the U.S. is important for understanding the barriers to purchasing coverage for the uninsured and evaluating the role of policy in reducing this number. We propose several definitions of affordability and examine the implications of alternative definitions on estimates of the proportion of currently uninsured who are unable to afford coverage. We find that, depending on the definition, health insurance was affordable to between one-quarter and three-quarters of the uninsured in 2000.

Health Risk, Income, and Employment-Based Health Insurance

While many believe that an individual’s health plays an important role in both their willingness and ability to obtain health insurance in the employment-based setting, relatively little agreement exists on the extent to which health status affects coverage rates, particularly for those with lower incomes. In this paper, we examine the relationship between health risk and the purchase of group health insurance and whether that relationship differs by a person’s income and whether they obtain coverage in the small, medium, or large group market. Using the panel component of the 1996-2002 Medical Expenditure Panel Survey (MEPS), we find that health risk is positively associated with private health insurance across the different markets, and that this positive relationship is stronger for low and middle income people, particularly in the large group market. Our results are consistent with the existence of adverse selection in the group market in the form of low rates of coverage among low risks due to an absence of risk rating of premiums. We conclude that pooled premiums for low risks, particularly those with low incomes, may represent a more important financial barrier to coverage in voluntary group insurance than high premiums for high risks.

Multivariate methods in aquaculture research: case studies of tilapias in experimental and commercial systems

This volume documents the usefulness of multivariate methods û notably multiple regression, path analysis and canonical correlation û in the context of aquaculture, which has to date tended to neglect such methods, and hence to underutilize available data. All examples used here stem from experimental and/or commercial tilapia culture systems, and hence this book also represents an advance in the understanding of such systems.Aquaculture, Tilapia culture, Growth, Multivariate analysis Oreochromis

A new method of alpha ray measurement using a Quadrupole Mass Spectrometer

We propose a new method of alpha($\alpha$)-ray measurement that detects helium atoms with a Quadrupole Mass Spectrometer(QMS). A demonstration is undertaken with a plastic-covered $^{241}$Am $\alpha$-emitting source to detect $\alpha$-rays stopped in the capsule. We successfully detect helium atoms that diffuse out of the capsule by accumulating them for one to 20 hours in a closed chamber. The detected amount is found to be proportional to the accumulation time. Our method is applicable to probe $\alpha$-emitting radioactivity in bulk material.Comment: 8 pages, 6 figure

Game logic for game theorists

Game Logic (GL), introduced in (Parikh, 1985), is examined from a game-theoretic perspective. A new semantics for GL is proposed in terms of untyped games which are closely related to extensive game forms of perfect information. An example is given of how GL can be used as a formal model of game situations, and some metatheoretic results are presented in the context of their game-theoretic relevance

Molecular dynamics study of the thermopower of Ag, Au, and Pt nanocontacts

Using molecular dynamics simulations of many junction stretching processes we analyze the thermopower of silver (Ag), gold (Au), and platinum (Pt) atomic contacts. In all cases we observe that the thermopower vanishes on average within the standard deviation and that its fluctuations increase for decreasing minimum cross-section of the junctions. However, we find a suppression of the fluctuations of the thermopower for the s-valent metals Ag and Au, when the conductance originates from a single, perfectly transmitting channel. Essential features of the experimental results for Au, Ag, and copper (Cu) of Ludoph and van Ruitenbeek [Phys. Rev. B 59, 12290 (1999)], as yet unaddressed by atomistic studies, can hence be explained by considering the atomic and electronic structure at the disordered narrowest constriction of the contacts. For the multivalent metal Pt our calculations predict the fluctuations of the thermopower to be larger by one order of magnitude as compared to Ag and Au, and suppressions of the fluctuations as a function of the conductance are absent.Comment: 13 pages, 10 figure

The worldwide costs of marine protected areas

Declines in marine harvests, wildlife, and habitats have prompted calls at both the 2002 World Summit on Sustainable Development and the 2003 World Parks Congress for the establishment of a global system of marine protected areas (MPAs). MPAs that restrict fishing and other human activities conserve habitats and populations and, by exporting biomass, may sustain or increase yields of nearby fisheries. Here we provide an estimate of the costs of a global MPA network, based on a survey of the running costs of 83 MPAs worldwide. Annual running costs per unit area spanned six orders of magnitude, and were higher in MPAs that were smaller, closer to coasts, and in high-cost, developed countries. Models extrapolating these findings suggest that a global MPA network meeting the World Parks Congress target of conserving 20–30% of the world’s seas might cost between $5 billion and$19 billion annually to run and would probably create around one million jobs. Although substantial, gross network costs are less than current government expenditures on harmful subsidies to industrial fisheries. They also ignore potential private gains from improved fisheries and tourism and are dwarfed by likely social gains from increasing the sustainability of fisheries and securing vital ecosystem services