Insights into the Behavior of Potential Structural Failures Originating from Localized High Stress Regions in Configurations Relevant to Solid Rocket Motor Nozzles

During the structural certification effort for the Space Launch System solid rocket booster nozzle, it was identified that no consistent method for addressing local negative margins of safety in non-metallic materials had been developed. Relevant areas included bond-line terminations and geometric features in the composite nozzle liners. In order to gain understanding, analog test specimens were designed that very closely mimic the conditions in the actual full scale hardware. Different locations in the nozzle were represented by different analog specimen designs. This paper describes those tests and corresponding results. Finite element analysis results for the tests are presented. Strain gage correlation of the analysis to the test results is addressed. Furthermore, finite fracture mechanics (a coupled stress and energy failure criterion) is utilized to predict the observed crack pop-in loads for the different configurations. The finite fracture mechanics predictions are found to be within a 10% error relative to the average measured pop-in load for each of four configurations. Initiation locations, arrest behaviors, and resistances to further post-arrest crack propagation are also discussed

The Use of Non-natural Nucleotides to Probe Template-Independent DNA Synthesis

The vast majority of DNA polymerases use the complementary templating strand of DNA to guide each nucleotide incorporation. There are instances, however, in which polymerases can efficiently incorporate nucleotides in the absence of templating information. This process, known as translesion DNA synthesis, can alter the proper genetic code of an organism. To further elucidate the mechanism of template-independent DNA synthesis, we monitored the incorporation of various nucleotides at the “blunt-end” of duplex DNA by the high-fidelity bacteriophage T4 DNA polymerase. Although natural nucleotides are not incorporated at the blunt-end, a limited subset of non-natural indolyl analogues containing extensive π-electron surface areas are efficiently utilized by the T4 DNA polymerase. These analogues possess high binding affinities that are remarkably similar to those measured during incorporation opposite an abasic site. In contrast, the kpol values are significantly lower during blunt-end extension when compared to incorporation opposite an abasic site. These kinetic differences suggest that the single-stranded region of the DNA template plays an important role during polymerization through stacking interactions with downstream bases, interactions with key amino acid residues, or both. In addition, we demonstrate that terminal deoxynucleotide transferase, a template-independent enzyme, can efficiently incorporate many of these non-natural nucleotides. However, that this unique polymerase cannot extend large, bulky non-natural nucleotides suggests that elongation is limited by steric constraints imposed by structural features present within the polymerase. Regardless, the kinetic data obtained from using either DNA polymerase indicate that template-independent synthesis can occur without the contributions of hydrogen-bonding interactions and suggest that π-electron interactions play an important role in polymerization efficiency when templating information is not present

Results from the Continued Lithic Analysis of the Sunrise Ridge Borrow Pit Site (45PI408), Mt. Rainer National Park, Washington

Prior research on the Sunrise Ridge Borrow Pit Site artifact assemblage has shown significant intra-site variation in stone tool manufacture and use. These findings were in some ways contrary to the expectations found within theoretical models of prehistoric land use at Mt. Rainier. Unfortunately, many of the previous investigations were limited by small sample sizes and the inability to determine if subtle differences were meaningful. Our research places an emphasis on using an evolutionary archaeological framework to combine previously analyzed collections, determine if there is evidence of change through time or across space, and attempts to identify selective conditions under which stone tools were made and used. Recent large scale excavations have increased sample sizes (+2,328 artifacts ≥ ¼”) and the subsequent lithic analysis has continued to assess intra-site variation. It appears as though lithic industries are relatively consistent through time, with some variation in heavy use areas of site. Including a shift away from non-local raw materials as well as variability in environmental conditions. Typically, curated technologies, which require more preparation than expedient technologies, are represented in the lithic assemblage. This is likely a consequence of the harsh environmental conditions at Mt. Rainier rather than any particular settlement and subsistence systems taking place at lower elevations. Additional evidence of the past environmental conditions that may have altered stone tool use in the Mt. Rainier area include increased fire frequency and the absence of gastroliths, or avian gizzard stones, in recent archaeological components

A Framework for Agreeing Standard Terminology

This document outlines a process that can be followed to reach agreement on standard terminology for a community or topic

Machine augmented composite materials for damping purposes

In this study the energy dissipation performance of machine augmented composite (MAC) materials is investigated. MAC materials are formed by inserting simple machines into a matrix material. In this work the machines take the form of fluid filled tubes, and the tube cross-sectional geometry induces fluid flow when it is deformed in its plane. This flow dissipates mechanical energy, and thus provides the composite material with attractive damping properties. The objective of this study is to gain insight into the geometry, the material property combinations, and the boundary conditions that are effective in producing high damping MAC materials. Particular attention is given to tube geometry and to dimensionless parameters that govern the energy dissipation efficiency of a MAC lamina. An important dimensionless parameter is the ratio of solid elastic moduli to the product of the driving frequency and the fluid dynamic viscosity. This is a measure of the ratio of elastic forces in the solid material to the viscous forces in the fluid material that makes up a MAC lamina. Governing equations and simulation methods are discussed. Simplified equations are derived to predict the pressure generated when a tube/matrix cell is squeezed with zero pressure end conditions. Transient, three dimensional finite element models are also used to predict the performance of the damping MAC materials with zero pressure at the ends of the tubes. For the geometry and material properties considered, the highest energy dissipation efficiency predicted by these models is approximately 0.8 out of a maximum of 1.0

Does slow and steady win the race? Rates of antipsychotic discontinuation, antipsychotic dose, and risk of psychotic relapse

Background Antipsychotics are recommended for prevention of relapse in schizophrenia. It is unclear whether increased risk of relapse following antipsychotic discontinuation is predominantly associated with an absolute magnitude of dose reduction or rate of antipsychotic reduction. Establishing the responsible mechanism is important because prolonged withdrawal schedules have been suggested to reduce risk of relapse. Study Design Individual patient data from antipsychotic discontinuation studies were obtained. We estimated the occupancy of receptors over time using half-lives and median effective dose ED50 values obtained from pharmacokinetic and receptor occupancy studies. Hazard ratios for relapse events were calculated using Cox proportional hazards models to assess the influence of formulation (oral, 1-monthly, and 3-monthly injections). The change in hazard ratio over time was estimated, and the effect of time-varying covariates was calculated, including rate of occupancy reduction and absolute receptor occupancy. Study Results Five studies including 1388 participants with schizophrenia were identified (k = 2: oral, k = 2: 1-monthly injection, k = 1: 3-monthly injection). Withdrawal of long-acting injectable medication did not lead to a lower hazard ratio compared with withdrawal of oral medication, and this included the period immediately following randomization. Hazard ratios were not associated with the rate of decline of receptor occupancy; however, they were associated with reduced absolute occupancy in trials of long-acting injections (P = .038). Conclusions Antipsychotic discontinuation is associated with an increased risk of psychotic relapse, related to receptor occupancy. Although relapse does not appear to be related to the rate of discontinuation, gradual discontinuation strategies may allow for easier antipsychotic reinstatement in case of symptomatic worsening

Implicit theories of a desire for fame

The aim of the present studies was to generate implicit theories of a desire for fame among the general population. In Study 1, we were able to develop a nine-factor analytic model of conceptions of the desire to be famous that initially comprised nine separate factors; ambition, meaning derived through comparison with others, psychologically vulnerable, attention seeking, conceitedness, social access, altruistic, positive affect, and glamour. Analysis that sought to examine replicability among these factors suggested that three factors (altruistic, positive affect, and glamour) neither display factor congruence nor display adequate internal reliability. A second study examined the validity of these factors in predicting profiles of individuals who may desire fame. The findings from this study suggested that two of the nine factors (positive affect and altruism) could not be considered strong factors within the model. Overall, the findings suggest that implicit theories of a desire for fame comprise six factors. The discussion focuses on how an implicit model of a desire for fame might progress into formal theories of a desire for fame

Genome-wide association studies of the self-rating of effects of ethanol (SRE).

The level of response (LR) to alcohol as measured with the Self-Report of the Effects of Alcohol Retrospective Questionnaire (SRE) evaluates the number of standard drinks usually required for up to four effects. The need for a higher number of drinks for effects is genetically influenced and predicts higher risks for heavy drinking and alcohol problems. We conducted genome-wide association study (GWAS) in the African-American (COGA-AA, N = 1527 from 309 families) and European-American (COGA-EA, N = 4723 from 956 families) subsamples of the Collaborative Studies on the Genetics of Alcoholism (COGA) for two SRE scores: SRE-T (average of first five times of drinking, the period of heaviest drinking, and the most recent 3 months of consumption) and SRE-5 (the first five times of drinking). We then meta-analyzed the two COGA subsamples (COGA-AA + EA). Both SRE-T and SRE-5 were modestly heritable (h2 : 21%-31%) and genetically correlated with alcohol dependence (AD) and DSM-IV AD criterion count (rg : 0.35-0.76). Genome-wide significant associations were observed (SRE-T: chromosomes 6, rs140154945, COGA-EA P = 3.30E-08 and 11, rs10647170, COGA-AA+EA P = 3.53E-09; SRE-5: chromosome13, rs4770359, COGA-AA P = 2.92E-08). Chromosome 11 was replicated in an EA dataset from the National Institute on Alcohol Abuse and Alcoholism intramural program. In silico functional analyses and RNA expression analyses suggest that the chromosome 6 locus is an eQTL for KIF25. Polygenic risk scores derived using the COGA SRE-T and SRE-5 GWAS predicted 0.47% to 2.48% of variances in AD and DSM-IV AD criterion count in independent datasets. This study highlights the genetic contribution of alcohol response phenotypes to the etiology of alcohol use disorders

CASRAI-UK: Using the CASRAI approach to develop standards for communicating and sharing research information in the UK

This paper explains how the Consortia Advancing Standards in Research Administration Information (CASRAI) might be used to share research information in an open and sustainably governed approach, led by research organisations. CASRAI is an international non-profit organisation dedicated to reducing administrative burden and improving outcomes and impact reporting through good stewardship of information requirements by research organisations (universities, colleges, teaching hospitals and other research centres). The objective is to improve the flow of information within and between research stakeholders. The approach sees the ‘user-led’ development and maintenance of standard information agreements. These agreements include (a) specifications defining what data elements (entities) are needed for various key business processes in the research lifecycle and (b) definitions for all the terms appearing in these specifications. The open and standardised definitions are curated and maintained in an open online dictionary that can then be used by system providers and others to exchange information in a standard, agreed format e.g.by using CERIF-XML as the transfer mechanism