Resolution correction for surface X-ray diffraction at high beam exit angles

Owing to the two-dimensional periodicity of a superstructure on the crystal surface, the intensity in reciprocal space is continuously distributed along rods normal to the sample surface. The analysis of rod scans in surface X-ray diffraction provides information about the structure parameters normal to the sample surface. For high resolution to be achieved, the measurements must extend to momentum transfers q that are as large as possible. At large exit angles, the conventional Lorentz factor must be modified to take account of the finite aperture of the detector and the continuous intensity along the lattice rod. For two types of Z-axis diffractometer used in surface X-ray crystallography, an analytical expression for the resolution correction of rod-scan intensity data has been developed. It takes into account an anisotropic detector resolution T(, ), the finite width of the diffracted beam and the primary-beam divergence parallel to the sample surface, . The calculation of the convolution functions is simplified by a projection onto the q = 0 plane. The effects of different detector settings and the influences of the primary-beam divergence and the sample quality on the measured intensity are demonstrated for several examples

Human Capital Risk, Contract Enforcement, and the Macroeconomy

We develop a macroeconomic model with physical and human capital, human capital risk, and limited contract enforcement. We show analytically that young (high-return) households are the most exposed to human capital risk and are also the least insured. We document this risk-insurance pattern in data on life-insurance drawn from the Survey of Consumer Finance. A calibrated version of the model can quantitatively account for the life-cycle variation of insurance observed in the US data and implies welfare costs of under-insurance for young households that are equivalent to a 4 percent reduction in lifetime consumption. A policy reform that makes consumer bankruptcy more costly leads to a substantial increase in the volume of credit and insurance.

Calvin Klein: Semiotic Phenomenology

This study examined print advertising as a visual communication method by focusing on five of Calvin Klein\u27s jeans advertisements and the themes that are expressed to determine what realities or social meanings Calvin Klein\u27s jeans advertisements constructed and/or reflected. To uncover the themes within Klein\u27s advertisements, the following three-methods were applied: Content Analysis, Informal Focus Group and Semiotic Phenomenology. Together the three-methods, based upon data collected from fourteen males and females aged 13-18, 19-21, 22-24 and 28 years old or above, identified fifteen underlying themes containing stereotypes, potentially dangerous realities and evidence showing our desensitization to controversy and shocking images through print advertising. The results showed that Klein\u27s advertisements both constructed and reflected reality, drawing a fine line between what is actually constructed and what is reflected. Sexual terminology was used 85% of the time to describe the ads and nothing was the second most used response to describe how the ads made the respondents feel. The females\u27 responses were more emotionally charged and focused on the sex and violence in the ad, where the males expressed negativity towards the unisex or bi-sexual ads and nothing to describe how the remaining ads made them feel. Results suggested that people today are more desensitized to shocking or provocative visual images portrayed in advertising, even though advertising is selling more than just the product. The results indicated that advertising fuels false images of love, sexuality, romance, success, body image, success and normalcy, prompting consumers to ask, what else is this ad selling

Pesin's Formula for Random Dynamical Systems on RdR^d

Pesin's formula relates the entropy of a dynamical system with its positive Lyapunov exponents. It is well known, that this formula holds true for random dynamical systems on a compact Riemannian manifold with invariant probability measure which is absolutely continuous with respect to the Lebesgue measure. We will show that this formula remains true for random dynamical systems on $R^d$ which have an invariant probability measure absolutely continuous to the Lebesgue measure on $R^d$. Finally we will show that a broad class of stochastic flows on $R^d$ of a Kunita type satisfies Pesin's formula.Comment: 35 page