599 research outputs found
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Heavy ion fusion system assessment: Final focus and transport model
This report discusses the trade-offs necessary to build an economical heavy ion fusion reactor. The principal concerns are the dynamics of the accelerated ion beam. 15 refs. (JDH
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Analysis of an induction linac driver system for inertial fusion
A linear induction accelerator that produces a beam of energetic (5 to 20 GeV) heavy (130 to 210 amu) ions is a prime candidate as a driver for inertial fusion. Continuing developments in sources for ions with charge state greater than unity allow a potentially large reduction in the driver cost and an increase in the driver efficiency. The use of high undepressed tunes (sigma/sub 0/ approx. = 85/sup 0/) and low depressed tunes (sigma approx. = 8.5/sup 0/) also contributes to a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system are discussed as a function of output energy and pulse repetition frequency for several ion masses and charge states. The cost optimization code LIACEP, including accelerating module alternatives, transport modules, and scaling laws, is presented. Items with large cost-leverage are identified as a guide to future research activities and development of technology that can yield substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency. Finally, a cost-effective strategy using heavy ion induction linacs in a development scenario for inertial fusion is presented. 34 refs., 6 figs., 7 tabs
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Cost of induction linac driver for inertial fusion for various target yields
The cost of induction linac accelerators for inertial fusion using mass 200 ions at a charge state of +3 for target yields of 300, 600, and 1200 MJ is presented. The ions are injected into the accelerator at 3 MV, and accelerated to the required voltage appropriate to the desired target yield. A cost comparison of the low voltage portion of the accelerator (3 to 50 MV) is made between a system with 64 and one with 16 superconducting quadrupoles. The design of the low voltage portion which yields the minimum-cost accelerator designs for several target yields and a fusion power of 3000 MW is presented
Stability and the Evolvability of Function in a Model Protein
Functional proteins must fold with some minimal stability to a structure that
can perform a biochemical task. Here we use a simple model to investigate the
relationship between the stability requirement and the capacity of a protein to
evolve the function of binding to a ligand. Although our model contains no
built-in tradeoff between stability and function, proteins evolved function
more efficiently when the stability requirement was relaxed. Proteins with both
high stability and high function evolved more efficiently when the stability
requirement was gradually increased than when there was constant selection for
high stability. These results show that in our model, the evolution of function
is enhanced by allowing proteins to explore sequences corresponding to
marginally stable structures, and that it is easier to improve stability while
maintaining high function than to improve function while maintaining high
stability. Our model also demonstrates that even in the absence of a
fundamental biophysical tradeoff between stability and function, the speed with
which function can evolve is limited by the stability requirement imposed on
the protein.Comment: Biophysical Journal in pres
Pain Coping Skills Training for African Americans With Osteoarthritis Study: Baseline Participant Characteristics and Comparison to Prior Studies
Background: The Pain Coping Skills Training for African Americans with OsteoaRTthritis (STAART) trial is examining the effectiveness of a culturally enhanced pain coping skills training (CST) program for African Americans with osteoarthritis (OA). This disparities-focused trial aimed to reach a population with greater symptom severity and risk factors for poor pain-related outcomes than previous studies. This paper compares characteristics of STAART participants with prior studies of CST or cognitive behavioral therapy (CBT)-informed training in pain coping strategies for OA.
Methods: A literature search identified 10 prior trials of pain CST or CBT-informed pain coping training among individuals with OA. We descriptively compared characteristics of STAART participants with other studies, in 3 domains of the National Institutes of Minority Health and Health Disparities' Research Framework: Sociocultural Environment (e.g., age, education, marital status), Biological Vulnerability and Mechanisms (e.g, pain and function, body mass index), and Health Behaviors and Coping (e.g., pain catastrophizing). Means and standard deviations (SDs) or proportions were calculated for STAART participants and extracted from published manuscripts for comparator studies.
Results: The mean age of STAART participants, 59 years (SD = 10.3), was lower than 9 of 10 comparator studies; the proportion of individuals with some education beyond high school, 75%, was comparable to comparator studies (61-86%); and the proportion of individuals who are married or living with a partner, 42%, was lower than comparator studies (62-66%). Comparator studies had less than about 1/3 African American participants. Mean scores on the Western Ontario and McMaster Universities Osteoarthritis Index pain and function scales were higher (worse) for STAART participants than for other studies, and mean body mass index of STAART participants, 35.2 kg/m2 (SD = 8.2), was higher than all other studies (30-34 kg/m2). STAART participants' mean score on the Pain Catastrophizing scale, 19.8 (SD = 12.3), was higher (worse) than other studies reporting this measure (7-17).
Conclusions: Compared with prior studies with predominantly white samples, STAART participants have worse pain and function and more risk factors for negative pain-related outcomes across several domains. Given STAART participants' high mean pain catastrophizing scores, this sample may particularly benefit from the CST intervention approach
Pain coping skills training for African Americans with osteoarthritis (STAART): study protocol of a randomized controlled trial
Background: African Americans bear a disproportionate burden of osteoarthritis (OA), with higher prevalence rates, more severe pain, and more functional limitations. One key barrier to addressing these disparities has been limited engagement of African Americans in the development and evaluation of behavioral interventions for management of OA. Pain Coping Skills Training (CST) is a cognitive-behavioral intervention with shown efficacy to improve OA-related pain and other outcomes. Emerging data indicate pain CST may be a promising intervention for reducing racial disparities in OA symptom severity. However, there are important gaps in this research, including incorporation of stakeholder perspectives (e.g. cultural appropriateness, strategies for implementation into clinical practice) and testing pain CST specifically among African Americans with OA. This study will evaluate the effectiveness of a culturally enhanced pain CST program among African Americans with OA.
Methods/Design: This is a randomized controlled trial among 248 participants with symptomatic hip or knee OA, with equal allocation to a pain CST group and a wait list (WL) control group. The pain CST program incorporated feedback from patients and other stakeholders and involves 11 weekly telephone-based sessions. Outcomes are assessed at baseline, 12ĆĀ weeks (primary time point), and 36ĆĀ weeks (to assess maintenance of treatment effects). The primary outcome is the Western Ontario and McMaster Universities Osteoarthritis Index, and secondary outcomes include self-efficacy, pain coping, pain interference, quality of life, depressive symptoms, and global assessment of change. Linear mixed models will be used to compare the pain CST group to the WL control group and explore whether participant characteristics are associated with differential improvement in the pain CST program. This research is in compliance with the Helsinki Declaration and was approved by the Institutional Review Boards of the University of North Carolina at Chapel Hill, Durham Veterans Affairs Medical Center, East Carolina University, and Duke University Health System.
Discussion: This culturally enhanced pain CST program could have a substantial impact on outcomes for African Americans with OA and may be a key strategy in the reduction of racial health disparities.Funded by Patient-Centered Outcomes Research Institute (PCORI) Award (AD-1408-19519)
Patients with schizophrenia show deficits of working memory maintenance components in circuit-specific tasks
Working memory (WM) deficits are a neuropsychological core finding in patients with schizophrenia and also supposed to be a potential endophenotype of schizophrenia. Yet, there is a large heterogeneity between different WM tasks which is partly due to the lack of process specificity of the tasks applied. Therefore, we investigated WM functioning in patients with schizophrenia using process- and circuit-specific tasks. Thirty-one patients with schizophrenia and 47 controls were tested with respect to different aspects of verbal and visuospatial working memory using modified Sternberg paradigms in a computer-based behavioural experiment. Total group analysis revealed significant impairment of patients with schizophrenia in each of the tested WM components. Furthermore, we were able to identify subgroups of patients showing different patterns of selective deficits. Patients with schizophrenia exhibit specific and, in part, selective WM deficits with indirect but conclusive evidence of dysfunctions of the underlying neural networks. These deficits are present in tasks requiring only maintenance of verbal or visuospatial information. In contrast to a seemingly global working memory deficit, individual analysis revealed differential patterns of working memory impairments in patients with schizophrenia
Manual / Issue 11 / Repair
Manual, a journal about art and its making. Repair. Can we find in the detail, in the stitch and the weave, an ecology of care, a model for activating new forms of life, ones that might reject or reimagine an economic and cultural order based on novelty, disposability, and the monadic self? Can they help us learn to live together in a broken world? āBrian Goldberg and Kate Irvin, from the preface to Issue 11
This volume complemented the exhibition Repair and Design Futures, on view at the RISD Museum October 5, 2018 through June 30, 2019. Softcover, 96 pages. Published 2018 by the RISD Museum. Manual 11 (Repair) contributors include Markus Berger, Gina Borromeo, Linda Catano, Thomas Denenberg, Daniel Eatock, Brian Goldberg, Ramiro Gomez, Kate Irvin, Anna Rose Keefe, Olivia Laing, Steven Lubar, Roberto Lugo, Lisa Z. Morgan, Maureen C. OāBrien, Barry Schwabsky, Sharma Shields, Jessica Urick, and Liliane Wong.https://digitalcommons.risd.edu/risdmuseum_journals/1037/thumbnail.jp
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