Lattice dynamics and correlated atomic motion from the atomic pair distribution function

The mean-square relative displacements (MSRD) of atomic pair motions in crystals are studied as a function of pair distance and temperature using the atomic pair distribution function (PDF). The effects of the lattice vibrations on the PDF peak widths are modelled using both a multi-parameter Born von-Karman (BvK) force model and a single-parameter Debye model. These results are compared to experimentally determined PDFs. We find that the near-neighbor atomic motions are strongly correlated, and that the extent of this correlation depends both on the interatomic interactions and crystal structure. These results suggest that proper account of the lattice vibrational effects on the PDF peak width is important in extracting information on static disorder in a disordered system such as an alloy. Good agreement is obtained between the BvK model calculations of PDF peak widths and the experimentally determined peak widths. The Debye model successfully explains the average, though not detailed, natures of the MSRD of atomic pair motion with just one parameter. Also the temperature dependence of the Debye model largely agrees with the BvK model predictions. Therefore, the Debye model provides a simple description of the effects of lattice vibrations on the PDF peak widths.Comment: 9 pages, 11 figure

Psychological and Environmental Correlates of HPA Axis Functioning in Parentally Bereaved Children: Preliminary Findings

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97514/1/jts21788.pd

Peak positions and shapes in neutron pair correlation functions from powders of highly anisotropic crystals

The effect of the powder average on the peak shapes and positions in neutron pair distribution functions of polycrystalline materials is examined. It is shown that for highly anisotropic crystals, the powder average leads to shifts in peak positions and to non-Gaussian peak shapes. The peak shifts can be as large as several percent of the lattice spacing

Is a Minimum Wage an Appropriate Instrument for Redistribution?

We analyse the redistributional (dis)advantages of a minimum wage over income taxation in competitive labour markets without imposing assumptions on the (in)efficiency of labour rationing. Compared to a distributionally equivalent tax change, a minimum-wage increase raises involuntary unemployment, but also raises skill formation as some individuals avoid unemployment. A minimum wage is an appropriate instrument for redistribution if and only if the public revenue gains from additional skill formation outweigh both the public revenue losses from additional unemployment and the utility losses of inefficient labour rationing. We show that this critically depends on how labour rationing is distributed among workers. A necessary condition for the desirability of a minimum-wage increase is that the public revenue gains from higher skill formation outweigh the revenue losses from higher unemployment. We write this condition in terms of measurable sufficient statistics

Associations among Adolescent Sleep Problems, Emotion Regulation, and Affective Disorders: Findings from a Nationally Representative Sample.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Sleep problems in youth reliably forecast the development of anxiety and mood disorders, presumably due to increased emotional difficulties. However, precise emotional mechanisms have yet to be delineated. The current study investigated how sleep problems in adolescence are associated with different emotion regulation strategies, and how sleep and psychiatric risk may be indirectly associated via poor emotion regulation. This study utilized data from the National Comorbidity Survey-Adolescent Supplement, a nationally representative sample from the United States (N = 10,148; age range 13–18 years). A diagnostic interview determined if adolescents qualified for a mood or anxiety disorder within the past year. Participants provided reports of their sleep, emotion regulation, and current life stress. Adolescents who reported greater sleep problems were more likely to qualify for a mood or anxiety disorder and generally reported poorer emotion regulation strategy use, even when accounting for demographic characteristics and current stress. Specifically, adolescents with greater sleep problems reported less problem solving, and greater avoidance, suppression, rumination, and acceptance. Sleep problems were indirectly associated with anxiety disorders through greater suppression and rumination, and indirectly associated with mood disorders through greater rumination and lower problem solving. Although cross-sectional, this study extends current research by suggesting that certain emotion regulation strategies may be more difficult for youth struggling with sleep problems, and provides initial evidence that poor emotion regulation may be one factor contributing to sleep-based psychiatric risk. These findings can inform more efficacious intervention efforts

The future impact of changes in rate parity agreements on hotel chains: the long-term implications of the removal of rate parity agreements between hotels and online travel agents using closed consumer group booking models

The Office of Fair Trading, a not-for-profit and non-ministerial government department of the United Kingdom (from April 2014 incorporated within the Competition and Markets Authority), investigated the legality of rate parity from 2012, particularly rate parity agreements made between Intercontinental Hotel Group, Booking.com, and Expedia. Consequently, these major hotel brands and agents have committed to remove rate parity for closed consumer groups. This article identifies confusion over such groups and longer term implications. Smaller agents will enter the market, leading to increased fragmentation and competition. Branded hotels will face tough challenges in protecting prices and value from aggressive agents suddenly facing a more competitive market and independent hoteliers able to establish effective relationships with the new, smaller agents. Keywords : Rate parity, pricing, closed consumer groups, hotels

Delays in Leniency Application: Is There Really a Race to the Enforcer's Door?

This paper studies cartels’ strategic behavior in delaying leniency applications, a take-up decision that has been ignored in the previous literature. Using European Commission decisions issued over a 16-year span, we show, contrary to common beliefs and the existing literature, that conspirators often apply for leniency long after a cartel collapses. We estimate hazard and probit models to study the determinants of leniency-application delays. Statistical tests find that delays are symmetrically affected by antitrust policies and macroeconomic fluctuations. Our results shed light on the design of enforcement programs against cartels and other forms of conspiracy

Priority for the Worse Off and the Social Cost of Carbon

The social cost of carbon (SCC) is a monetary measure of the harms from carbon emission. Specifically, it is the reduction in current consumption that produces a loss in social welfare equivalent to that caused by the emission of a ton of CO2. The standard approach is to calculate the SCC using a discounted-utilitarian social welfare function (SWF)—one that simply adds up the well-being numbers (utilities) of individuals, as discounted by a weighting factor that decreases with time. The discounted-utilitarian SWF has been criticized both for ignoring the distribution of well-being, and for including an arbitrary preference for earlier generations. Here, we use a prioritarian SWF, with no time-discount factor, to calculate the SCC in the integrated assessment model RICE. Prioritarianism is a well-developed concept in ethics and theoretical welfare economics, but has been, thus far, little used in climate scholarship. The core idea is to give greater weight to well-being changes affecting worse off individuals. We find substantial differences between the discounted-utilitarian and non-discounted prioritarian SCC