Demonstration of a two-dimensional divertor Thomson scattering system on DIII-D.

Recent upgrades providing two-dimensional divertor Thomson scattering (DTS-2D) measurements of Te and ne during a DIII-D plasma shot and a thorough description of system components and their functionality are presented. This system expands the capabilities of the existing single divertor Floor measurement location by introducing seven additional laser beam path options in the poloidal plane, spanning major radii from 1.062 to 1.335 m. The system redirects ∼1 J, 50 Hz Nd:YAG laser pulses to the new beam paths within 20 ms, stepping through each path on the divertor Floor every 200 ms during a plasma shot. The laser is redirected using an ex-vessel, fast-steering mirror to one of eight in-vessel beam paths oriented underneath the vessel tiles. Up to eleven measurement positions per beam path, from -1.35 to -1.13 m below the machine midplane, are available by dynamically refocusing the ex-vessel collection fiber array using a high-speed linear stage. Current measurement positions above the divertor Shelf are retained via a hole in the fixed, in-vessel mirror, allowing laser pass through.

In-Person and Virtual World Mindfulness Training: Trust, Satisfaction, and Learning.

Virtual worlds (VWs) present a viable, low-cost delivery mechanism for telehealth services. Although preliminary reports support the effectiveness of VWs in terms of health metrics, few studies have examined the perceived benefits and learning potential for military service members and veterans. Trust is integral to any interaction and may be even more important, and problematic to establish, during virtual interactions than in-person (IP) communications. The purpose of this study was to compare active duty and veteran U.S. Military service members' (n = 92) self-reported trust, class satisfaction, and didactic learning after completing either an 8-week training course in mindfulness-based stress reduction (MBSR) delivered IP or an 8-week mindfulness meditation class based on MBSR via the VW of Second Life. Results showed that learning performance was not significantly different between the IP and VW groups (p > 0.05). Although overall trust was high for both groups, participants in the IP group reported greater trust and class satisfaction compared with the VW group (p < 0.05). Trust, satisfaction, and learning were significantly correlated with one another, and trust in the instructor significantly predicted trust-in-classmates, trust-in-self, and class satisfaction for both groups (p < 0.05). In this study, IP group training was superior to VW training in terms of self-reported greater trust in the instructor, classmates, and self, and higher satisfaction with the training. Trust in the instructor is particularly important for group training, whether IP or in a VW. This study reiterates the arduous task of establishing trust in a VW setting and suggests that creating trust between the instructor and participants is high priority as a leading objective for VW communications. Suggestions for building trust are tight collaboration and clear communication, along with supporting and advocating for one another.

Characteristics and Impact of U.S. Military Blast-Related Mild Traumatic Brain Injury: A Systematic Review.

As a result of armed conflict, head trauma from exposure to blasts is an increasing critical health issue, particularly among military service members. Whilst numerous studies examined the burden of blast-related brain injuries on service members', few systematic reviews have been published. This work provides a comprehensive summary of the evidence on blast-related mild traumatic brain injury (mTBI) burden in active U.S. military service members and inactive Veterans, describing characteristics and outcomes. Records published up to April 2017 were identified through a search of PubMed, Web of Science, Scopus, Ovid MEDLINE, and Cochrane Library. Records-based and original research reporting on U.S. military service members and Veterans with mild blast TBI were included. Data on subject characteristics, exposure, diagnostic criterion, and outcomes were extracted from included studies using a standardized extraction form and were presented narratively. Of the 2,290 references identified by the search, 106 studies with a total of 37,515 participants met inclusion criteria for blast-related mTBI. All but nine studies were based out of military or Veteran medical facilities. Unsurprisingly, men were over-represented (75-100%). The criteria used to define blast-related mTBI were consistent; however, the methodology used to ascertain whether individuals met those criteria for diagnosis were inconsistent. The diagnosis, most prevalent among the Army, heavily relied on self-reported histories. Commonly reported adverse outcomes included hearing disturbances and headaches. The most frequently associated comorbidities were post-traumatic stress disorder, depression, anxiety, sleep disorders, attention disorders, and cognitive disorders. The primary objective of this review was to provide a summary of descriptive data on blast-related mTBI in a U.S. military population. Low standardization of the methods for reaching diagnosis and problems in the study reporting emphasize the importance to collect high-quality data to fill knowledge gaps pertaining to blast-related mTBI.

The Effect of Traumatic Brain Injury (TBI) on Cognitive Performance in a Sample of Active Duty U.S. Military Service Members.

INTRODUCTION: Traumatic brain injury (TBI) is considered a signature injury from the fighting in Iraq and Afghanistan. Since the year 2000, over 370,000 U.S. active duty service members have been diagnosed with TBI. Although prior research has shown that even mild forms of TBI are associated with impaired cognitive performance, it is not clear which facets of cognition (computation, memory, reasoning, etc.) are impacted by injury. METHOD: In the present study, we compared active duty military volunteers (n = 88) with and without TBI on six measures of cognition using the Automated Neuropsychological Assessment Metric software. RESULTS: Healthy volunteers exhibited significantly faster response times on the matching-to-sample, mathematical processing, and second round of simple reaction time tasks and had higher throughput scores on the mathematical processing and the second round of the simple reaction time tasks (P < 0.05). CONCLUSION: In this population, cognitive impairments associated with TBI influenced performance requiring working memory and basic neural processing (speed/efficiency).

Self-Reported Sleep, Anxiety, and Cognitive Performance in a Sample of U.S. Military Active Duty and Veterans.

Unhealthy sleep can interfere with U.S. military service members affective and cognitive functioning, and increase accident and injury risks. This study examined the relationship between U.S. active duty and veterans' (n = 233) self-reported sleep (Pittsburgh Sleep Quality Index), anxiety (Zung Self-Rating Anxiety Scale), and cognitive performance (Automated Neuropsychological Assessment Metric). Statistical analyses included Pearson product moment correlations and multivariate analysis of variance, with Tukey-b post-hoc tests, with a p < 0.05 significance level. Higher education, abstinence from sleep aids, longer time in active duty service, and being on active duty were correlated with better sleep and lower anxiety. Greater sleep disturbance, poor sleep quality, and sleepiness-related daytime dysfunction were associated with greater anxiety and slower response times, and lower response accuracy. Statistically controlling for anxiety diminished the magnitude and significance of the correlations between sleep and cognitive performance, suggesting that reducing anxiety will improve sleep and diminish cognitive performance effects. These findings suggest the need for addressing both sleep and anxiety for those with diagnosed sleep disorders, as well as using a procedural systems approach to decrease anxiety during missions that demand outstanding cognitive performance.

Impact of In-Person and Virtual World Mindfulness Training on Symptoms of Post-Traumatic Stress Disorder and Attention Deficit and Hyperactivity Disorder.

Mindfulness meditation training has been shown to reduce stress and improve short-term memory for military personnel. However, no studies have investigated the effects of in-person and virtual world (VW) mindfulness training on Post-Traumatic Stress Disorder (PTSD) or Attention Deficit Hyperactivity Disorder (ADHD) symptoms. In this study, U.S. military active duty service members and veterans were pseudo-randomized into two mindfulness training groups: in-person (IP) and online via a VW, and a wait-list control group. Volunteers answered a demographic questionnaire, and completed the PTSD Checklist-Military Version (PCL-M) and ADHD Current Symptoms Scale before and after training. The results showed practical and clinically relevant reductions in PTSD symptoms, particular for the IP group, but did not show statistical relevance with hypothesis testing. Results also showed post-training reductions in ADHD symptoms for both IP and VW groups, but no change for the control group. To investigate the effects of initial ADHD symptoms, IP and VW groups were combined into a single Mindfulness Training group. Those with high-initial ADHD symptoms attending training showed improvements, but the control group did not. These results expand research on the mindfulness training, and suggest that IP mindfulness training, rather than VW training, may be of greater benefit for those with PTSD symptoms, while either delivery system appears adequate for reducing attentional symptoms.

Speed-dependent Voigt lineshape parameter database from dual frequency comb measurements at temperatures up to 1305 K. Part II: Argon-broadened H2O absorption, 6801-7188 cm-1.

We report argon-broadened water vapor transition parameters and their temperature dependence based on measured spectra spanning 6801-7188 cm-1 from a broad-bandwidth, high-resolution dual frequency comb spectrometer. The 25 collected spectra of 2% water vapor in argon ranged from 296 K to 1305 K with total pressure spanning 100 Torr to 600 Torr. A multispectrum fitting routine was used in conjunction with a quadratic speed-dependent Voigt profile to extract broadening and shift parameters, and a power-law temperature-dependence exponent for both. The measurements represent the first broad bandwidth, argon-broadened water vapor absorption study, and are an important step toward a foreign-gas-perturbed, high-temperature database developed using advanced lineshape profiles.

Speed-dependent Voigt lineshape parameter database from dual frequency comb measurements up to 1305 K. Part I: Pure H2O absorption, 6801-7188 cm-1.

We measure speed-dependent Voigt lineshape parameters with temperature-dependence exponents for several hundred spectroscopic features of pure water spanning 6801-7188 cm-1. The parameters are extracted from broad bandwidth, high-resolution dual frequency comb absorption spectra with multispectrum fitting techniques. The data encompass 25 spectra ranging from 296 K to 1305 K and 1 to 17 Torr of pure water vapor. We present the extracted parameters, compare them to published data, and present speed-dependence, self-shift, and self-broadening temperature-dependent parameters for the first time. Lineshape data is extracted using a quadratic speed-dependent Voigt profile and a single self-broadening power law temperature-dependence exponent over the entire temperature range. The results represent an important step toward a new high-temperature database using advanced lineshape profiles.

Broadband, high-resolution investigation of advanced absorption line shapes at high temperature.

Spectroscopic studies of planetary atmospheres and high-temperature processes (e.g., combustion) require absorption line-shape models that are accurate over extended temperature ranges. To date, advanced line shapes, like the speed-dependent Voigt and Rautian profiles, have not been tested above room temperature with broadband spectrometers. We investigate pure water vapor spectra from 296 to 1305 K acquired with a dual-frequency comb spectrometer spanning from 6800 to 7200 cm-1 at a point spacing of 0.0033 cm-1 and absolute frequency accuracy of <3.3 × 10-6 cm-1. Using a multispectral fitting analysis, we show that only the speed-dependent Voigt accurately models this temperature range with a single power-law temperature-scaling exponent for the broadening coefficients. Only the data from the analysis using this profile fall within theoretical predictions, suggesting that this mechanism captures the dominant narrowing physics for these high-temperature conditions.

The effects of age on processing and storage in working memory span tasks and reading comprehension.

UNLABELLED: BACKGROUND/STUDY CONTEXT: Declines in verbal working memory span task performance have been associated with deficits in the language processing abilities of healthy older adults, but it is unclear how storage and processing contribute to this relationship. Moreover, recent studies of the psychometric properties of span measures in the general cognitive literature highlight the need for a critical reassessment of age-related differences in working memory task performance. METHODS: Forty-two young (Mage = 19.45 years) and 42 older participants (Mage = 73.00 years) completed a series of neuropsychological screening measures, four memory span tasks (one-syllable word span, three-syllable word span, reading span, and sentence span), and a measure of reading comprehension. Each span measure was completed under self-paced and timed encoding conditions. A 2 (age) × 2 (task type) × 2 (encoding conditions) mixed-model design was used. RESULTS: (1) Age effects were reliable for both simple and complex span task performance; (2) limiting the available encoding time yielded lower recall scores across tasks and exacerbated age differences in simple span performance; and (3) both encoding condition and age affected the relationship between each of the span measures and the relationship between span and reading comprehension. CONCLUSION: Declines in both storage and processing abilities contributed to age differences in span task performance and the relationship between span and reading comprehension. Although older people appear to benefit from task administration protocols that promote successful memory encoding, researchers should be aware of the potential risks to validity posed by such accommodations.

The influence of story context on a working memory span task.

The purpose of the present study was to examine factors that could influence whether recall performance in the reading span task (Daneman & Carpenter, 1980 ) would benefit from the contextual information from the sentences in the processing component of the task. More specifically, we investigated whether people would benefit from sentence sets that formed short stories or when the entire span task was one continuous story. Overall, there was a clear benefit for contextually related sentence sets (i.e., the story span tasks) compared to the traditional reading span task. However, the benefit was eliminated when the entire set formed one continuous story. These results support the recall reconstruction hypothesis for working memory (Towse, Cowan, Hitch, & Horton, 2008 ), which suggests that people may strategically use the content of the sentences from the processing component of the reading span task as memorial cues to reconstruct the target words of the storage component. However, this benefit is constrained to scenarios when the contextual cues are unique to a specific set.

Relationship between perceived stigma and depression severity.

The purpose of this study was to explore the relationship between perceived stigma and being in treatment for depression and current depression severity. Face-to-face interviews were conducted with a convenience sample of depressed subjects from a Veterans Administration outpatient mental health clinic (N = 54) and never-depressed subjects from a Veterans Administration primary care clinic (N = 50). Depression severity was measured using the 9-item Primary Care Evaluation of Mental Disorders depression measure. Stigma was measured using the 5-item Stigma Scale for Receiving Psychological Help modified for depression treatment. Statistical analyses included Spearman correlation and multivariate regression. In the correlation analysis, being in treatment for depression compared with never experiencing depression was associated with significantly higher levels of perceived stigma (p <.001). In separate multivariate models controlling for significant univariate correlates, greater depression severity (p <.001) and meeting criteria for current major depression (p <.001) were significant predictors of perceived stigma. Greater depression severity appears to be a strong predictor of perceived stigma.