Scaling Relationships of Gaussian Processes

Asset returns conforming to a Gaussian random walk are characterised by the temporal independence of the moments of the distribution. Employing currency returns, this note demonstrates the conditions that are necessary for risk to be estimated in this manner.Scaling; Volatility; Currency Returns

Single Parent Success In Mississippi\u27s Community Colleges

On an average year, over 90,000 students enroll in a Mississippi community college. Until now, no data were available to identify the number of students enrolled in the Mississippi community college system who were single parents. No data were available to determine if there was a relationship between being a single parent and fall-to-fall retention. Each of the fifteen Mississippi community colleges were asked to provide data on the 2016 cohort of students. Data collected were race/ethnicity, academic program (transfer or career/technical), three questions from the FAFSA to determine a student’s single parent status, if each student was retained from the Fall 2016 to the Fall 2017 semester, grade point average at 100% of time to degree (four semesters), and if the student completed a degree after four semesters. Four colleges provided usable data for the study, representing 8.6% (8,427) of the 98,013 students enrolled in for-credit courses in the Fall 2016 semester. The study found 12.4% of students in the sample were single parents. The average grade point average of single parents was 2.62. The average grade point average of non-single parents was 2.55. Separate Chi-square tests were used to determine if a significant relationship existed between single parent status (yes or no), single parents’ gender, single parents’ race/ethnicity, and fall-to-fall retention. Additionally, the independent T-test statistic was used to determine if a significant difference existed between single parent status and grade point average. Results shothat single parent status (single parent or not) had a strong relationship between fall-to-fall retention status (retained or not) as well as a significant difference in grade point average after four semesters. Gender and race/ethnicity did not have a significant relationship with fall-to-fall retention among the sample

Measurement of Quantum Fluctuations in Geometry

A particular form for the quantum indeterminacy of relative spacetime position of events is derived from the limits of measurement possible with Planck wavelength radiation. The indeterminacy predicts fluctuations from a classically defined geometry in the form of ``holographic noise'' whose spatial character, absolute normalization, and spectrum are predicted with no parameters. The noise has a distinctive transverse spatial shear signature, and a flat power spectral density given by the Planck time. An interferometer signal displays noise due to the uncertainty of relative positions of reflection events. The noise corresponds to an accumulation of phase offset with time that mimics a random walk of those optical elements that change the orientation of a wavefront. It only appears in measurements that compare transverse positions, and does not appear at all in purely radial position measurements. A lower bound on holographic noise follows from a covariant upper bound on gravitational entropy. The predicted holographic noise spectrum is estimated to be comparable to measured noise in the currently operating interferometer GEO600. Because of its transverse character, holographic noise is reduced relative to gravitational wave effects in other interferometer designs, such as LIGO, where beam power is much less in the beamsplitter than in the arms.Comment: 7 pages, 2 figures, LaTeX. Extensive rewrite of original version, including more detailed analysis. Main result is the same but the estimate of noise in strain units for GEO600, showing 1/f behavior at low f and flat at high f, is improved. To appear in Phys. Rev.

Some Consumer Surplus Estimates for North Carolina Beaches

We estimate consumer surplus of a beach day using the single-site travel cost method. Onsite visitation data for seven North Carolina beaches were collected between July and November of 2003. Two pooled count data models, corrected for endogenous stratification and truncation, are estimated to account for bias stemming from onsite sampling. One model pertains to beach visitors that make single day trips to the beach, while the other is for visitors that stay onsite overnight. In each model, we allow for heterogeneity across sites through intercept-shifting and demand slope-shifting dummy variables. Depending upon the site, the estimated net benefits of a day at a beach in North Carolina range between $11 and$80 for those users making day trips and between $11 and$41 for those users that stay onsite overnight. These estimates are of the same order of magnitude as the results from earlier studies using travel cost methods but are considerably larger than the previous findings based upon stated preference methods.travel cost, consumer surplus, beach access, Resource /Energy Economics and Policy, D12, D63, H31, Q26,