Residual Stresses and Critical Initial Flaw Size Analyses of Welds

An independent assessment was conducted to determine the critical initial flaw size (CIFS) for the flange-to-skin weld in the Ares I-X Upper Stage Simulator (USS). A series of weld analyses are performed to determine the residual stresses in a critical region of the USS. Weld residual stresses both increase constraint and mean stress thereby having an important effect on the fatigue life. The purpose of the weld analyses was to model the weld process using a variety of sequences to determine the 'best' sequence in terms of weld residual stresses and distortions. The many factors examined in this study include weld design (single-V, double-V groove), weld sequence, boundary conditions, and material properties, among others. The results of this weld analysis are included with service loads to perform a fatigue and critical initial flaw size evaluation

Feasibility of Conducting J-2X Engine Testing at the Glenn Research Center Plum Brook Station B-2 Facility

A trade study of the feasibility of conducting J-2X testing in the Glenn Research Center (GRC) Plum Brook Station (PBS) B-2 facility was initiated in May 2006 with results available in October 2006. The Propulsion Test Integration Group (PTIG) led the study with support from Marshall Space Flight Center (MSFC) and Jacobs Sverdrup Engineering. The primary focus of the trade study was on facility design concepts and their capability to satisfy the J-2X altitude simulation test requirements. The propulsion systems tested in the B-2 facility were in the 30,000-pound (30K) thrust class. The J-2X thrust is approximately 10 times larger. Therefore, concepts significantly different from the current configuration are necessary for the diffuser, spray chamber subsystems, and cooling water. Steam exhaust condensation in the spray chamber is judged to be the key risk consideration relative to acceptable spray chamber pressure. Further assessment via computational fluid dynamics (CFD) and other simulation capabilities (e.g. methodology for anchoring predictions with actual test data and subscale testing to support investigation

Relativistic Treatment of Hypernuclear Decay

We compute for the first time the decay width of lambda-hypernuclei in a relativistic mean-field approximation to the Walecka model. Due to the small mass difference between the lambda-hyperon and its decay products---a nucleon and a pion---the mesonic component of the decay is strongly Pauli blocked in the nuclear medium. Thus, the in-medium decay becomes dominated by the non-mesonic, or two-body, component of the decay. For this mode, the lambda-hyperon decays into a nucleon and a spacelike nuclear excitation. In this work we concentrate exclusively on the pion-like modes. By relying on the analytic structure of the nucleon and pion propagators, we express the non-mesonic component of the decay in terms of the spin-longitudinal response function. This response has been constrained from precise quasielastic (p,n) measurements done at LAMPF. We compute the spin-longitudinal response in a relativistic random-phase-approximation model that reproduces accurately the quasielastic data. By doing so, we obtain hypernuclear decay widths that are considerably smaller---by factors of two or three---relative to existing nonrelativistic calculations.Comment: Revtex: 18 pages and 4 postscript figure

Rare Copy Number Variants in \u3cem\u3eNRXN1\u3c/em\u3e and \u3cem\u3eCNTN6\u3c/em\u3e Increase Risk for Tourette Syndrome

Tourette syndrome (TS) is a model neuropsychiatric disorder thought to arise from abnormal development and/or maintenance of cortico-striato-thalamo-cortical circuits. TS is highly heritable, but its underlying genetic causes are still elusive, and no genome-wide significant loci have been discovered to date. We analyzed a European ancestry sample of 2,434 TS cases and 4,093 ancestry-matched controls for rare (\u3c 1% frequency) copy-number variants (CNVs) using SNP microarray data. We observed an enrichment of global CNV burden that was prominent for large (\u3e 1 Mb), singleton events (OR = 2.28, 95% CI [1.39–3.79], p = 1.2 × 10−3) and known, pathogenic CNVs (OR = 3.03 [1.85–5.07], p = 1.5 × 10−5). We also identified two individual, genome-wide significant loci, each conferring a substantial increase in TS risk (NRXN1 deletions, OR = 20.3, 95% CI [2.6–156.2]; CNTN6 duplications, OR = 10.1, 95% CI [2.3–45.4]). Approximately 1% of TS cases carry one of these CNVs, indicating that rare structural variation contributes significantly to the genetic architecture of TS

Strangeness nuclear physics: a critical review on selected topics

Selected topics in strangeness nuclear physics are critically reviewed. This includes production, structure and weak decay of $\Lambda$--Hypernuclei, the $\bar K$ nuclear interaction and the possible existence of $\bar K$ bound states in nuclei. Perspectives for future studies on these issues are also outlined.Comment: 63 pages, 51 figures, accepted for publication on European Physical Journal

Psychological and Mnemonic Benefits of Nostalgia for People with Dementia

BACKGROUND: Studies with non-clinical populations show that nostalgia increases psychological resources, such as self-esteem and social connectedness.OBJECTIVES: Our objectives were to find out if the benefits of nostalgia in non-clinical populations generalize to people with dementia and if nostalgia facilitates recall of dementia-related information.METHODS: All three experiments recruited participants with mild or moderate levels of dementia. Experiment 1 tested whether nostalgia (compared to control) enhances psychological resources among 27 participants. Experiment 2 used music to induce nostalgia (compared to control) in 29 participants. Experiment 3 compared recall for self-referent dementia statements among 50 participants randomized to either a nostalgia or control condition. Findings across experiments were synthesized with integrative data analysis.RESULTS: Nostalgia (compared to control) significantly increased self-reported social connectedness, meaning in life, self-continuity, optimism, self-esteem, and positive (but not negative) affect (Experiments 1-3). Compared to controls, nostalgic participants also recalled significantly more self-referent dementia-related information (Experiment 3).CONCLUSION: This series of experiments extends social psychological research with non-clinical populations into dementia care, providing evidence that nostalgia significantly enhances psychological resources. The finding that nostalgia increased recall of self-referent statements about dementia suggests that this emotion lends participants the fortitude to face the threat posed by their illness. The finding has potentially important clinical implications both for the development of reminiscence therapy and for facilitating adjustment to a diagnosis of dementia.</p

Nostalgia as a psychological resource for people with dementia: A systematic review and meta-analysis of evidence of effectiveness from experimental studies

Objective: This review systematically examines evidence relating to the effect of nostalgia on psychological well-being through a meta-analysis of measures of social connectedness, self-esteem, meaning in life, self-continuity, optimism and positive and negative affect. Rationale: If nostalgia is to be used as a clinical intervention to boost well-being in dementia by reducing threat, then it is important to assess its therapeutic potential. Results: Searches carried out in July 2014 and updated in February 2018 identified 47 eligible experimental studies comparing nostalgic reminiscence and non-nostalgic reminiscence to be included in the meta-analysis. Nostalgic reminiscence had moderate effects on positive affect (0.51 (0.37, 0.65), p= 0.001), social connectedness (0.72 (0.57, 0.87), p= 0.001), self-esteem (0.50 (0.30, 0.70), p= 0.001), meaning in life (0.77 (0.47, 1.08), p= 0.001) and optimism (0.38 (0.28, 0.47), p= 0.001) and a large effect on self-continuity (0.81 (0.55, 1.07), p= 0.001). There was, however, no difference between the effect of nostalgic reminiscence and non-nostalgic reminiscence for negative affect (−0.06 (−0.20, 0.09), p= 0.443). Conclusion: This systematic review and meta-analysis provides an overview of the evidence base for nostalgia. This is an important stage in developing nostalgia as a clinical intervention for people with dementia which might be achieved, for instance, by adapting current reminiscence and life review techniques. This meta-analysis will therefore also serve as a valuable reference point for the continued exploration of nostalgia as an intervention

Mindfulness meditation for sleep disturbances among individuals with cognitive impairment: A scoping review

Background: This scoping review investigates the effectiveness of mindfulness meditation in alleviating sleep disturbances among individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). With the rising prevalence of dementia and its profound impact on cognitive function and quality of life, this review aims to synthesize existing research and identify gaps in the literature. Methods: We systematically searched six electronic databases (CINAHL, Embase, Medline, PsycINFO, PubMed, and Scopus) from 2004 to 2024, yielding 462 potentially relevant articles. Screening was conducted using ASReview, an AI ranking tool, which facilitated the selection of studies. Ultimately, seven studies that met our stringent eligibility criteria were included in the review. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines for reporting. Results: Our findings indicate that mindfulness meditation significantly improves sleep quality, reduces insomnia severity, and enhances overall well-being in this at-risk population. Notably, interventions that combine structured, face-to-face sessions with at-home practice emerged as the most effective. Conclusions: Despite these positive outcomes, methodological limitations, including small sample sizes and reliance on self-reported measures, underscore the need for more rigorous long-term studies. This review highlights the potential of mindfulness meditation as a low-cost, scalable intervention to improve sleep and cognitive health in older adults, paving the way for future research and clinical applications