Femtosecond Pump-Probe Diagnostics Of Preformed Plasma Channels

We report on recent ultrafast pump-probe experiments 28 in He plasma waveguides using 800 nm, 80 fs pump pulses of 0.2 x 1018 W/cm2 peak guided intensity, and single orthogonally-polarized 800 nm probe pulses with similar to0.1% of pump intensity. The main results are: (1) We observe frequency-domain interference between the probe and a weak, depolarized component of the pump that differs substantially in mode shape from the injected pump pulse; (2) we observe spectral blue-shifts in the transmitted probe that are not evident in the transmitted pump. The evidence indicates that pump depolarization and probe blue-shifts both originate near the channel entrance.Physic

Development Of Third Harmonic Generation As A Short Pulse Probe Of Shock Heated Material

We are studying high-pressure laser produced shock waves in silicon (100). To examine the material dynamics, we are performing pump-probe style experiments utilizing 600 ps and 40 fs laser pulses from a Ti:sapphire laser. Two-dimensional interferometry reveals information about the shock breakout, while third harmonic light generated at the rear surface is used to infer the crystalline state of the material as a function of time. Sustained third harmonic generation (THG) during a similar to 100 kbar shock breakout indicate that the rear surface remains crystalline for at least 3 ns. However, a decrease in THG during a similar to 300 kbar shock breakout suggests a different behavior, which could include a change in crystalline structure.Mechanical Engineerin

Late Life Depressive Symptoms and Cognitive Function among Older Mexican Adults: The Past and the Present

Objective: To evaluate associations between depression and individual cognitive domains and how changes in depressive symptoms relate to cognition three years later in the context of Mexico, a developing country experiencing rapid aging. Method: Data comes from waves 3 (2012) and 4 (2015) of the Mexican Health and Aging Study (n=12,898, age 50+). Depression is ascertained using a modified Center for Epidemiologic Studies – Depression Scale. Cognition is assessed using verbal learning, verbal memory, visual scanning, verbal fluency, visuospatial ability, visual memory, and orientation tasks. Depressive symptoms and cognitive functioning were both measured in 2012 and 2015. Scores across cognitive domains are modeled using ordinary least squares regression, adjusting for demographic, health, and economic covariates. Results: When depression and cognition were measured concurrently in 2015, depression exhibited associations with all cognitive domains. When considering a respondent’s history of depression, individuals who had elevated depressive symptoms in 2012 and recovered by 2015 continued to exhibit poorer cognitive function in 2015 in verbal learning, verbal memory, visual scanning, and verbal fluency tasks compared to individuals who were neither depressed in 2012 nor 2015. Conclusions: Depression was associated with cognition across cognitive domains among older Mexican adults. Despite improvements in depressive symptomatology, formerly depressed respondents continued to perform worse than their counterparts without a history of depression on several cognitive tasks. In addition to current mental health status, researchers should consider an individual’s history of depression when assessing the cognitive functioning of older adults

The pooling of interest method of accounting-what is the problem?

Dispute over whether or not the pooling of interests method of accounting is theoretically justified is rapidly growing as a result of recent proposals from many accounting bodies throughout the world. This paper examines that the debate and the question as to whether or not the method is appropriate

Cost Effectiveness of Bio-Gas Systems for Dairy Farms

Considerable attention has recently been focused on the development of farm management practices that utilize the total resource potential of animal wastes. In addition to the fertilizer value of manure, energy in the form of bio-gas can be generated from manure wastes by an anaerobic digestion process. The purpose of this economic analysis was to evaluate the feasibility of producing energy from the anaerobic digestion of dairy-cow manure. Anaerobic digestion systems were rationally designed for several farm management practices on Vermont dairy farms. These designs were sized to accommodate dairy herds of 20, 50, 100, and 200 cows for both free- and tie-stall arrangements. The realistic evaluation of the potential of any energy source must include a cost effectiveness analysis. This 1974 economic analysis, with selected 1977 cost updatings, included considerations of both the total annual financial investment and the unit cost of net energy production. Minimum unit costs of net energy production for 1977 prices are approximately $0.19 per kwh for the 20-cow operation, but these values decrease with increasing herd size to$0.05 per kwh for the 200-cow dairy farm. At the present time, the generation of bio-gas from the anaerobic digestion of dairy farm manures becomes economically feasible as an alternate source of energy for dairy farms in excess of 200 cows

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

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