Analytic height correlation function of rough surfaces derived from light scattering

We derive an analytic expression for the height correlation function of a rough surface based on the inverse wave scattering method of Kirchhoff theory. The expression directly relates the height correlation function to diffuse scattered intensity along a linear path at fixed polar angle. We test the solution by measuring the angular distribution of light scattered from rough silicon surfaces, and comparing extracted height correlation functions to those derived from atomic force microscopy (AFM). The results agree closely with AFM over a wider range of roughness parameters than previous formulations of the inverse scattering problem, while relying less on large-angle scatter data. Our expression thus provides an accurate analytical equation for the height correlation function of a wide range of surfaces based on measurements using a simple, fast experimental procedure.Comment: 6 pages, 5 figures, 1 tabl

Frequency-Domain Streak Camera And Tomography For Ultrafast Imaging Of Evolving And Channeled Plasma Accelerator Structures

We demonstrate a prototype Frequency Domain Streak Camera (FDSC) that can capture the picosecond time evolution of the plasma accelerator structure in a single shot. In our prototype Frequency-Domain Streak Camera, a probe pulse propagates obliquely to a sub-picosecond pump pulse that creates an evolving nonlinear index >bubble> in fused silica glass, supplementing a conventional Frequency Domain Holographic (FDH) probe-reference pair that co-propagates with the >bubble>. Frequency Domain Tomography (FDT) generalizes Frequency-Domain Streak Camera by probing the >bubble> from multiple angles and reconstructing its morphology and evolution using algorithms similar to those used in medical CAT scans. Multiplexing methods (Temporal Multiplexing and Angular Multiplexing) improve data storage and processing capability, demonstrating a compact Frequency Domain Tomography system with a single spectrometer.Physic

The necessity of accommodation in size constancy

The necessity of accommodation in size constanc

Cohort Differences in Cognitive Impairment and Cognitive Decline Among Mexican-Americans Aged 75 Years or Older

Research suggests that the prevalence and incidence of cognitive impairment among older adults is decreasing. This analysis used data from 9 waves (1993–2016) of the Hispanic Established Populations for the Epidemiologic Study of the Elderly to assess cognitive status and cognitive decline for 2 cohorts of Mexican-Americans aged ≥75 years in 1993–1994 versus 2004–2005. Logistic regression, joint longitudinal survival models, and illness-death models for interval-censored data were used to examine cohort differences in the odds of prevalent cognitive impairment, trajectories of cognitive decline, and the risk of 10-year incident cognitive impairment, respectively. Results indicated that compared with the 1993–1994 cohort, the 2004–2005 cohort had higher odds for prevalent cognitive impairment (odds ratio = 2.51, 95% confidence interval (CI): 1.92, 3.29), particularly among participants with \u3c4 years of education (odds ratio = 2.99, 95% CI: 2.14, 4.18). Conversely, the 2004–2005 cohort exhibited significantly slower rates of cognitive decline (βˆ = 0.50, 95% CI: 0.39, 0.62) and had a significantly lower risk of incident cognitive impairment (hazard ratio = 0.75, 95% CI: 0.62, 0.91) compared with the 1993–1994 cohort. This analysis provides mixed results for cohort trends in the cognitive health of older Mexican-Americans. Continued research is needed to identify risk factors that contribute to these population-level trends

Lower Risk of 10-Year Incident Cognitive Impairment for Mexican Americans Aged 75 and Older in 2004-05 Compared to 1993-94

There is growing evidence for a decline in the prevalence and incidence of Alzheimer’s disease and related dementias. These findings have been attributed to greater educational attainment, reduced incidenced of stroke, and better management of chronic health conditions. However, limited research has examined if the declining trend in dementia risk are also occurring in minority populations, especially Mexican Americans. Methods: Data: This analysis used data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly (H-EPESE) to examine differences in the 10-year risk of cognitive impairment for Mexican Americans aged 75 and older in 2004-05 compared to Mexican Americans aged 75 and older in 1993-9

Cohort Differences in Cognitive Impairment and Cognitive Decline Among Mexican-Americans Aged 75 Years or Older

Research suggests that the prevalence and incidence of cognitive impairment among older adults is decreasing. This analysis used data from 9 waves (1993–2016) of the Hispanic Established Populations for the Epidemiologic Study of the Elderly to assess cognitive status and cognitive decline for 2 cohorts of Mexican-Americans aged ≥75 years in 1993–1994 versus 2004–2005. Logistic regression, joint longitudinal survival models, and illness-death models for interval-censored data were used to examine cohort differences in the odds of prevalent cognitive impairment, trajectories of cognitive decline, and the risk of 10-year incident cognitive impairment, respectively. Results indicated that compared with the 1993–1994 cohort, the 2004–2005 cohort had higher odds for prevalent cognitive impairment (odds ratio = 2.51, 95% confidence interval (CI): 1.92, 3.29), particularly among participants with \u3c4 years of education (odds ratio = 2.99, 95% CI: 2.14, 4.18). Conversely, the 2004–2005 cohort exhibited significantly slower rates of cognitive decline (βˆ = 0.50, 95% CI: 0.39, 0.62) and had a significantly lower risk of incident cognitive impairment (hazard ratio = 0.75, 95% CI: 0.62, 0.91) compared with the 1993–1994 cohort. This analysis provides mixed results for cohort trends in the cognitive health of older Mexican-Americans. Continued research is needed to identify risk factors that contribute to these population-level trends

Aging and Disability Among Hispanics in the United States: Current Knowledge and Future Directions

Background and Objectives: Hispanics are the most rapidly aging minority population in the United States. Our objective is to provide a summary of current knowledge regarding disability among Hispanics, and to propose an agenda for future research. Research Design and Methods: A literature review was conducted to identify major areas of research. A life course perspective and the Hispanic Paradox were used as frameworks for the literature review and for identifying future areas of research. Results: Four research areas were identified: (1) Ethnic disparities in disability; (2) Heterogeneity of the U.S. older Hispanic population; (3) Risk factors for disability; and (4) Disabled life expectancy. Older Hispanics are more likely than non- Hispanic whites to be disabled or to become disabled. Disability varied by country of origin, nativity, age of migration, and duration in the United States. Important risk factors for disability included chronic health conditions, depression, and cognitive impairment. Protective factors included positive affect and physical activity. Older Hispanics have longer life expectancy than non-Hispanic whites but spend a greater proportion of old age disabled. Future research should continue to monitor trends in disability as younger generations of Hispanics reach old age. Attention needs to be given to regional variation within the United States for disability prevalence, early-life risk factors, and factors that may contribute to variation in disabled life expectancy. There is also an urgent need for interventions that can effectively prevent or delay the onset of disability in older Hispanics. Discussion and Implications: Considerable research has examined disability among older Hispanics, but continued research is needed. It is important that research findings be used to inform public policies that can address the burden of disability for older Hispanic populations

Effects of fire on forest soil and nutrient cycling: an annotated bibliography, Station Bulletin, no.514

The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire

An investigation of the changes in binocular accommodative rock performance as a function of spherical lenses

This study has been conducted to determine the change in cycles per minute as a function of dioptric change in lens power on the plus and minus binocular accommodative rock

Multi-GeV Electron Generation Using Texas Petawatt Laser

We present simulation results and experimental setup for multi-GeV electron generation by a laser plasma wake field accelerator (LWFA) driven by the Texas Petawatt (TPW) laser. Simulations show that, in plasma of density n(e) = 2 - 4 x cm(-3), the TPW laser pulse (1.1 PW, 170 fs) can self-guide over 5 Rayleigh ranges, while electrons self-injected into the LWFA can accelerate up to 7 GeV. Optical diagnostic methods employed to observe the laser beam self-guiding, electron trapping and plasma bubble formation and evolution are discussed. Electron beam diagnostics, including optical transition radiation (OTR) and electron gamma ray shower (EGS) generation, are discussed as well.Physic