Fractionation of copper activation products in debris samples from the National Ignition Facility.

Nuclear fusion experiments performed at the National Ignition Facility produce radioactive debris, arising in reactions of fast neutrons with the target assembly. We have found that postshot debris collections are fractionated, such that isotope ratios in an individual debris sample may not be representative of the radionuclide inventory produced by the experiment. We discuss the potential sources of this fractionation and apply isotope-correlation techniques to calculate unfractionated isotope ratios that are used in measurements of nuclear reaction cross sections.

Distribution of collected target debris using the large area solid debris radiochemistry collector.

A large area solid radiochemistry collector was deployed at the National Ignition Facility (NIF) with a collection efficiency for post-shot, solid target debris of approximately 1% of the total 4π solid angle. The collector consisted of a 20-cm diameter vanadium foil surrounded by an aluminum side-enclosure and was fielded 50 cm from the NIF target. The collector was used on two NIF neutron yield shots, both of which had a monolayer of 238U embedded in the capsule ablator 10 µm from the inner surface. Fission and activation products produced in the 238U were collected, and subsequent analyses via gamma spectroscopy indicated that the distribution of fission products was not uniform, with peak and valley fission products preferentially collected on the vanadium and low- and high-mass fission products primarily located on the aluminum side-enclosure. The results from these shots will be used to design future nuclear data experiments at NIF.

Rapid improvement in beliefs, mood, and performance following an experimental success experience in an analogue test of recovery-oriented cognitive therapy.

BACKGROUND: Negative symptoms significantly contribute to disability and lack of community participation for low functioning individuals with schizophrenia. Cognitive therapy has been shown to improve negative symptoms and functional outcome in this population. Elucidation of the mechanisms of the therapy would lead to a better understanding of negative symptoms and the development of more effective interventions to promote recovery. The objective of this study was to determine (1) whether guided success at a card-sorting task will produce improvement in defeatist beliefs, positive beliefs about the self, mood, and card-sorting performance, and (2) whether these changes in beliefs and mood predict improvements in unguided card-sorting. METHODS: Individuals with schizophrenia having prominent negative symptoms and impaired neurocognitive performance (N = 35) were randomized to guided success (n = 19) or a control (n = 16) condition. RESULTS: Controlling for baseline performance, the experimental group performed significantly better, endorsed defeatist beliefs to a lesser degree, reported greater positive self-concept, and reported better mood than the control condition immediately after the experimental session. A composite index of change in defeatist beliefs, self-concept, and mood was significantly correlated with improvements in card-sorting. CONCLUSIONS: This analogue study supports the rationale of cognitive therapy and provides a general therapeutic model in which experiential interventions that produce success have a significant immediate effect on a behavioral task, mediated by changes in beliefs and mood. The rapid improvement is a promising indicator of the responsiveness of this population, often regarded as recalcitrant, to cognitively-targeted behavioral interventions.

From neurocognition to community participation in serious mental illness: the intermediary role of dysfunctional attitudes and motivation.

BACKGROUND: Evidence for a relationship between neurocognition and functional outcome in important areas of community living is robust in serious mental illness research. Dysfunctional attitudes (defeatist performance beliefs and asocial beliefs) have been identified as intervening variables in this causal chain. This study seeks to expand upon previous research by longitudinally testing the link between neurocognition and community participation (i.e. time in community-based activity) through dysfunctional attitudes and motivation. METHOD: Adult outpatients with serious mental illness (N = 175) participated, completing follow-up assessments approximately 6 months after initial assessment. Path analysis tested relationships between baseline neurocognition, emotion perception, functional skills, dysfunctional attitudes, motivation, and outcome (i.e. community participation) at baseline and follow-up. RESULTS: Path models demonstrated two pathways to community participation. The first linked neurocognition and community participation through functional skills, defeatist performance beliefs, and motivation. A second pathway linked asocial beliefs and community participation, via a direct path passing through motivation. Model fit was excellent for models predicting overall community participation at baseline and, importantly, at follow-up. CONCLUSIONS: The existence of multiple pathways to community participation in a longitudinal model supports the utility of multi-modal interventions for serious mental illness (i.e. treatment packages that build upon individuals' strengths while addressing the array of obstacles to recovery) that feature dysfunctional attitudes and motivation as treatment targets.

Recent advances and results from the solid radiochemistry nuclear diagnostic at the National Ignition Facility.

The solid debris collection capability at the National Ignition Facility has been expanded to include a third line-of-sight assembly. The solid radiochemistry nuclear diagnostic measurement of the ratio of gold isotopes is dependent on the efficient collection of neutron-activated hohlraum debris by passive metal disks. The collection of target debris at this new location is more reliable in comparison to the historic locations, and it appears to be independent of collector surface ablation.

Note: Radiochemical measurement of fuel and ablator areal densities in cryogenic implosions at the National Ignition Facility.

A new radiochemical method for determining deuterium-tritium (DT) fuel and plastic ablator (CH) areal densities (ρR) in high-convergence, cryogenic inertial confinement fusion implosions at the National Ignition Facility is described. It is based on measuring the (198)Au/(196)Au activation ratio using the collected post-shot debris of the Au hohlraum. The Au ratio combined with the independently measured neutron down scatter ratio uniquely determines the areal densities ρR(DT) and ρR(CH) during burn in the context of a simple 1-dimensional capsule model. The results show larger than expected ρR(CH) values, hinting at the presence of cold fuel-ablator mix.

Radiochemical determination of Inertial Confinement Fusion capsule compression at the National Ignition Facility.

We describe a radiochemical measurement of the ratio of isotope concentrations produced in a gold hohlraum surrounding an Inertial Confinement Fusion capsule at the National Ignition Facility (NIF). We relate the ratio of the concentrations of (n,γ) and (n,2n) products in the gold hohlraum matrix to the down-scatter of neutrons in the compressed fuel and, consequently, to the fuel's areal density. The observed ratio of the concentrations of (198m+g)Au and (196g)Au is a performance signature of ablator areal density and the fuel assembly confinement time. We identify the measurement of nuclear cross sections of astrophysical importance as a potential application of the neutrons generated at the NIF.

Solid debris collection for radiochemical diagnostics at the National Ignition Facility.

Radiochemical analysis of post-ignition debris inside the National Ignition Facility (NIF) target chamber can help determine various diagnostic parameters associated with the implosion efficiency of the fusion capsule. This technique is limited by the ability to distinguish ablator material from other debris and by the collection efficiency of the capsule debris after implosion. Prior to designing an on-line collection system, the chemical nature and distribution of the debris inside the chamber must be determined. The focus of our current work has been on evaluating capture of activated Au hohlraum debris on passive foils (5 cm diameter, 50 cm from target center) post-shot. Preliminary data suggest that debris distribution is locally heterogeneous along the equatorial and polar line-of-sights.

Take a walk in the park? A cross-over pilot trial comparing brisk walking in two different environments: park and urban.

OBJECTIVE: The objective of the present study is to investigate whether differences exist between a 30 minute brisk walk taken in two different environments in order to determine which environment best facilitates current physical activity guidelines: park or urban. METHODS: In this randomised cross-over pilot study, participants performed a self-timed 30 minute brisk walk in two different environments, park and urban, in Glasgow, Scotland (October 2009 to January 2010). Cadence, recorded using the activPAL™ activity monitor, was used to measure intensity. Outcome measures were: mean cadence; moderate-to-vigorous physical activity time accumulated in bouts lasting ≥ 10 min; number of walking breaks; and duration. RESULTS: A convenience sample of 40 healthy adults was recruited: 16 males, 24 females, mean age 22.9 (5.5) years. The mean cadence for the whole walk was higher in the park: 119.3 (8.3) vs. 110.9 (8.9) steps/min. Participants accumulated more moderate-to-vigorous physical activity in ≥ 10 minute bouts during park walks: 25.5 (9.6) [median (interquartile range)] vs. 14.0 (20.3) min. There was no difference in self-timed duration between locations. CONCLUSION: Participants accumulated more moderate-to-vigorous physical activity in bouts ≥ 10 min in duration on park walks due to the lack of interruptions in walking. Hence the park environment better facilitated the achievement of current physical activity guidelines. Further research involving a larger, more heterogeneous sample is recommended.

Enhancement of a virtual reality wheelchair simulator to include qualitative and quantitative performance metrics.

The increasing importance of inclusive design and in particular accessibility guidelines established in the U.K. 1996 Disability Discrimination Act (DDA) has been a prime motivation for the work on wheelchair access, a subset of the DDA guidelines, described in this article. The development of these guidelines mirrors the long-standing provisions developed in the U.S. In order to raise awareness of these guidelines and in particular to give architects, building designers, and users a physical sensation of how a planned development could be experienced, a wheelchair virtual reality system was developed. This compares with conventional methods of measuring against drawings and comparing dimensions against building regulations, established in the U.K. under British standards. Features of this approach include the marriage of an electromechanical force-feedback system with high-quality immersive graphics as well as the potential ability to generate a physiological rating of buildings that do not yet exist. The provision of this sense of "feel" augments immersion within the virtual reality environment and also provides the basis from which both qualitative and quantitative measures of a building's access performance can be gained.

Evaluation sensitivity as a moderator of communication disorder in schizophrenia.

BACKGROUND: Communication disturbance (thought disorder) is a central feature of schizophrenia that predicts poor functioning. We investigated the hypothesis that memory and attention deficits interact with beliefs about the gravity of being rejected (i.e. evaluation sensitivity) to produce the symptoms of communication disorder. METHOD: Seventy-four individuals diagnosed with schizophrenia or schizo-affective disorder completed a battery of tests assessing neurocognition (attention, working and verbal memory, abstraction), symptomatology (positive, negative and affective), functioning, and dysfunctional beliefs. RESULTS: Patients with communication deviance (n=33) performed more poorly on the neurocognitive tests and reported a greater degree of sensitivity to rejection than patients with no thought disorder (n=41). In a logistic regression analysis, evaluation sensitivity moderated the relationship between cognitive impairment and the presence of communication disorder. This finding was independent of hallucinations, delusions, negative symptoms, depression and anxiety. CONCLUSIONS: We propose that negative appraisals about acceptance instigate communication anomalies in individuals with a pre-existing diathesis for imperfect speech production.

The validation of a novel activity monitor in the measurement of posture and motion during everyday activities.

BACKGROUND: Accurate measurement of physical activity patterns can be used to identify sedentary behaviour and may facilitate interventions aimed at reducing inactivity. OBJECTIVE: To evaluate the activPAL physical activity monitor as a measure of posture and motion in everyday activities using observational analysis as the criterion standard. METHODS: Wearing three activPAL monitors, 10 healthy participants performed a range of randomly assigned everyday tasks incorporating walking, standing and sitting. Each trial was captured on a digital camera and the recordings were synchronised with the activPAL. The time spent in different postures was visually classified and this was compared with the activPAL output. RESULTS: Intraclass correlation coefficients (ICC 2,1) for interdevice reliability ranged from 0.79 to 0.99. Using the Bland and Altman method, the mean percentage difference between the activPAL monitor and observation for total time spent sitting was 0.19% (limits of agreement -0.68% to 1.06%) and for total time spent upright was -0.27% (limits of agreement -1.38% to 0.84%). The mean difference for total time spent standing was 1.4% (limits of agreement -6.2% to 9.1%) and for total time spent walking was -2.0% (limits of agreement -16.1% to 12.1%). A second-by-second analysis between observer and monitor found an overall agreement of 95.9%. CONCLUSION: The activPAL activity monitor is a valid and reliable measure of posture and motion during everyday physical activities.

The validity and reliability of a novel activity monitor as a measure of walking.

BACKGROUND: The accurate measurement of physical activity is crucial to understanding the relationship between physical activity and disease prevention and treatment. OBJECTIVE: The primary purpose of this study was to investigate the validity and reliability of the activPAL physical activity monitor in measuring step number and cadence. METHODS: The ability of the activPAL monitor to measure step number and cadence in 20 healthy adults (age 34.5+/-6.9 years; BMI 26.8+/-4.8 (mean+/-SD)) was evaluated against video observation. Concurrently, the accuracy of two commonly used pedometers, the Yamax Digi-Walker SW-200 and the Omron HJ-109-E, was compared to observation for measuring step number. Participants walked on a treadmill at five different speeds (0.90, 1.12, 1.33, 1.56, and 1.78 m/s) and outdoors at three self selected speeds (slow, normal, and fast). RESULTS: At all speeds, inter device reliability was excellent for the activPAL (ICC (2,1)> or =0.99) for both step number and cadence. The absolute percentage error for the activPAL was <1.11% for step number and cadence regardless of walking speed. The accuracy of the pedometers was adversely affected by slow walking speeds. CONCLUSION: The activPAL monitor is a valid and reliable measure of walking in healthy adults. Its accuracy is not influenced by walking speed. The activPAL may be a useful device in sports medicine.

The importance of comprehensive agricultural education in land-grant institutions: a historical perspective.

Any thorough examination of the present and future of agricultural education must certainly begin with a look into its past. Since the creation of the United States, many leading American philosophers have viewed a strong agrarian culture as the bedrock of American vigor. These same philosophers repeatedly noted the significance of comprehensive agricultural education to a nation rich in agricultural wealth. The signing of the Agricultural Colleges Act legitimized the concept of formal education in the agricultural sciences and provided funding for such education. The Act, which came to be known as the Morrill Act, after one of its primary authors, stressed the importance of comprehensive education. In fact, the inclusion of liberal studies was specifically mentioned in the Morrill Act and was defended repeatedly by Morrill himself. Comprehensive education prevented graduating technically trained students who were lacking in the basic outcomes of education--critical, comprehensive problem solving, cohesive thought, and effective communication. However, throughout history, the demands of a growing population coupled with rapid advancements in scientific knowledge led to a gradual move away from comprehensive education in agricultural sciences toward increasing specialization, resulting in more narrowly trained students. Today's agricultural students are technically well versed but often lack the skill and knowledge required for cohesive thought and critical problem solving. Addressing the multitude of challenges facing leaders in the future of agriculture requires much more than technical skill. These challenges require quick, yet careful thinkers and communicators who can respond to changing market structure and consumer demand in a dynamic way. Students who are a product of a conscious move toward amalgamation of burgeoning scientific knowledge and technical prowess with an integrative education emphasizing relationships between disciplines would better serve tomorrow's agriculture.

Restoration tactics for seriously corroded Cu and Cu-alloy firearms evidence.

A cleaning procedure for seriously weathered or corroded bullets and cartridge casings was developed and implemented for evidence specimens from a multiple homicide. The restoration protocol entailed successive treatments with increasingly aggressive chemical solvents and cleaning solutions while monitoring the progress of the method by optical microscopy. Treatment of worst-case, Cu-alloy jacketed bullets and casings resulted in reconditioned specimens that subsequently underwent successful firearms examinations.

Time-frequency and time-scale techniques for the classification of native and bioprosthetic heart valve sounds.

The determination of diagnostic features in recorded heart sounds was investigated with Carpentier-Edwards (CE) bioprosthetic valves. Morphological features, extracted using the Choi-Williams distribution, achieved between 96 and 61% correct classification. The time-scale wavelet-transform feature set achieved 100% correct classification with native valve populations, and 87% with the CE replacements.

Transient isotachophoretic-electrophoretic separations of lanthanides with indirect laser-induced fluorescence detection.

Indirect laser-induced fluorescence was used for the detection of several lanthanide species separated by capillary electrophoresis. Quinine sulfate was the fluorescent component of the background electrolyte, and α-hydroxyisobutyric acid was added as a complexing agent to enable the separation of analyte ions that have similar mobilities. The UV lines (333-364 nm) of an argon ion laser were used as the excitation source with a diode array detector for monitoring the fluorescent emission at 442 nm. Electrokinetic injections and transient isotachophoresis were implemented to stack the analyte ions into more concentrated zones. On-line preconcentration factors were determined to be ∼700 and resulted in limits of detection for La(3+), Ce(3+), Pr(3+), Nd(3+), Sm(3+), and Eu(3+) in the low-ppb range (6-11 nM).

A possible chemical explanation for the events associated with the death of Gloria Ramirez at Riverside General Hospital.

The events associated with the death of Gloria Ramirez at Riverside General Hospital on 19 February 1994 have been portrayed as a major medical mystery. A potential chemical explanation for this incident has been developed. The hypothetical scenario depends upon the oxidation of a common solvent, dimethyl sulfoxide, through dimethyl sulfone to dimethyl sulfate. The latter compound is a volatile and highly toxic agent that can be quite hazardous to humans in small amounts. It is also environmentally nonpersistent. Much of the mystery surrounding the circumstances at the hospital may be explainable if this postulated metabolic pathway took place at the time of the emergency room incident. Although dimethyl sulfate was not detected in any analyses pertinent to this event, there are plausible scientific explanations to account for that fact. The sulfate anion, a hydrolysis product of dimethyl sulfate, was measured at an appreciably elevated concentration in Ramirez' blood. The descriptions of the symptoms of the hospital-staff victims appear quite consistent with dimethyl sulfate exposures. This paper attempts to make some sense of the reported data and eyewitness accounts, and perhaps provide new insight for any future research that could further explain this reported occurrence of toxic exposure.

Chemical and elemental comparison of two formulations of oleoresin capsicum.

In-custody deaths following the application of pepper spray weaponry by law enforcement personnel have increased in California over the last few years. Oleoresin capsicum (OC), an oily extract of hot peppers, is the active ingredient in the spray, but little detailed information on product mixtures is available. Since OC extracts contain a multitude of natural compounds at irregular concentrations, there could be considerable, variation in overall chemical composition among the different formulations of both 'natural' and 'synthetic' OC preparations. This was confirmed by organic and inorganic analyses performed on OC sprays produced by two manufacturers licensed for distribution within the state of California. The results indicated that the differences could lead to considerable inconsistency in weapon effectiveness, and suggested that more comprehensive studies are warranted.