Experiences with the use of axisymmetric elements in cosmic NASTRAN for static analysis

Discussed here are some recent finite element modeling experiences using the axisymmetric elements CONEAX, TRAPAX, and TRIAAX, from the COSMIC NASTRAN element library. These experiences were gained in the practical application of these elements to the static analysis of helicopter rotor force measuring systems for two design projects for the NASA Ames Research Center. These design projects were the Rotor Test Apparatus and the Large Rotor Test Apparatus, which are dedicated to basic helicopter research. Here, a genetic axisymmetric model is generated for illustrative purposes. Modeling considerations are discussed, and the advantages and disadvantages of using axisymmetric elements are presented. Asymmetric mechanical and thermal loads are applied to the structure, and single and multi-point constraints are addressed. An example that couples the axisymmetric model to a non-axisymmtric model is demonstrated, complete with DMAP alters. Recommendations for improving the elements and making them easier to use are offered

The Ultra-Fast Outflow of WKK 4438: Suzaku and NuSTAR X-ray Spectral Analysis

Previous X-ray spectral analysis has revealed an increasing number of AGNs with high accretion rates where an outflow with a mildly relativistic velocity originates from the inner accretion disk. Here we report the detection of a new ultra-fast outflow (UFO) with a velocity of $v_{\rm out}=0.319^{+0.005}_{-0.008}c$ in addition to a relativistic disk reflection component in a poorly studied NLS1 WKK~4438, based on archival \nustar and \suzaku observations. The spectra of both \suzaku and \nustar observations show an Fe~\textsc{xxvi} absorption feature and the \suzaku data also show evidence for an Ar~\textsc{xviii} with the same blueshift. A super-solar argon abundance ($Z^{\prime}_{\rm Ar}>6Z_{\odot}$) and a slight iron over-abundance ($Z^{\prime}_{\rm Fe}=2.6^{+1.9}_{-2.0}Z_{\odot}$) are found in our spectral modelling. Based on Monte-Carlo simulations, the detection of the UFO is estimated to be around at 3$\sigma$ significance. The fast wind most likely arises from a radius of $\geq20r_g$ away from the central black hole. The disk is accreting at a high Eddington ratio ($L_{\rm bol}=0.4-0.7L_{\rm Edd}$). The mass outflow rate of the UFO is comparable with the disk mass inflow rate ($\dot M_{\rm out}>30\%\dot M_{\rm in}$), assuming a maximum covering factor. The kinetic power of the wind might not be high enough to have influence in AGN feedback ($\dot E_{\rm wind}/L_{\rm bol}\approx 3-5\%$) due to a relatively small column density ($12^{+9}_{-4}\times10^{22}$~cm$^{-2}$). However note that both the inferred velocity and the column density could be lower limits owing to the low viewing angle ($i=23^{+3}_{-2}$$^{\circ}$).Comment: 7 pages, 3 figures, accepted by MNRA

Prader Willi syndrome: systematic review of the prevalence and nature of presentation of unipolar depression

Purpose – The purpose of this paper is to assess the prevalence and nature of presentation of unipolar depression in individuals with Prader-Willi syndrome (PWS). Design/methodology/approach – The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) (2009) checklist for systematic reviews was followed where possible. Findings – Seven studies were included in the qualitative synthesis from a total of 261 records identified. The quality of the studies was then assessed: scores for each study design ranged from between 3 and 6 of a possible score total of 6. The frequency of depression ranged between studies from 4 to 22 per cent. four studies showed over 50 per cent of patients appeared to suffer from psychotic symptoms. Low mood, anhedonia and irritability were described as features of depression, although no fixed pattern of psychopathology arose from across the studies (excluding psychosis). This review has provided evidence to suggest that depression is a frequent occurrence in the PWS population. One study found that the incidence of depression differed between the genetic subtypes, raising questions regarding the relationship between genotype and behavioural phenotypes. A high proportion of individuals with depression suffered from psychotic symptoms. Research limitations/implications – The small number of heterogeneous studies included in this study precluded meta-analysis of the results. This highlights the need for further original research in this field. Practical implications – An increased awareness of the frequency of depressive symptoms within the PWS population will aid in the timely diagnosis and management of the disorder which will reduce psychiatric morbidity. The noted high proportion of psychotic symptoms associated with depression should raise the index of suspicion with clinicians and aid appropriate management decisions. Originality/value – This review has provided preliminary evidence for the nature of presentation of unipolar depression in PWS. It has highlighted the possibility of an increased propensity towards depression with psychotic symptoms. There is some suggestion of a differing presentation and course of unipolar depression between the common genetic subtypes of PWS which warrants further investigation

Sulfur and phosphorus oxyacid radicals

Authors thank the University of St. Andrews and the EaStCHEM Research Computing Facility for financial and computational support.We report a computational study of the little-studied neutral bisulfite, bisulfate, dihydro-phosphite and dihydro–phosphate radicals (HSOx•, H2POx•, x = 3,4), calling special attention to their various tautomeric structures together with pKa values estimated from the Gibbs free energies of their dissociations (at the G4 and CAM-B3LYP levels of density functional theory). The energetics of microhydration clusters with up to 4 water molecules for the S-based species and up to 8 waters for the P-based species were investigated. The number of microhydrating water molecules needed to induce spontaneous de-protonation is found to correlate the acid strength of each radical. According to computed Gibbs free reaction and activation energies, S- and P-centered radicals preferentially add to the double bond of propene (a lipid model), whereas the O-centered radical tautomers prefer H-abstraction. The likely downstream reactions of these radicals in biological media are discussed.Publisher PDFPeer reviewe

Implementing Packaged Software

This article presents a model of the implementation process for dedicated packages and describes a research project to test the model undertaken with the cooperation of a major computer vendor. Data were collected from 78 individuals in 18 firms using the package and from the package vendor. The results of the study offer some support for the model, along with suggestions for package implementation for both the customer and package vendor.Information Systems Working Papers Serie

A comparison of the polytomous Rasch analysis output of RUMM2030 and R (ltm/eRm/TAM/lordif)

© 2019 The Author(s). Background: Patient-reported outcome measures developed using Classical Test Theory are commonly comprised of ordinal level items on a Likert response scale are problematic as they do not permit the results to be compared between patients. Rasch analysis provides a solution to overcome this by evaluating the measurement characteristics of the rating scales using probability estimates. This is typically achieved using commercial software dedicated to Rasch analysis however, it is possible to conduct this analysis using non-specific open source software such a R. Methods: Rasch analysis was conducted using the most commonly used commercial software package, RUMM 2030, and R, using four open-source packages, with a common data set (6-month post-injury PRWE Questionnaire responses) to evaluate the statistical results for consistency. The analysis plan followed recommendations used in a similar study supported by the software package\u27s instructions in order to obtain category thresholds, item and person fit statistics, measures of reliability and evaluate the data for construct validity, differential item functioning, local dependency and unidimensionality of the items. Results: There was substantial agreement between RUMM2030 and R with regards for most of the results, however there are some small discrepancies between the output of the two programs. Conclusions: While the differences in output between RUMM2030 and R can easily be explained by comparing the underlying statistical approaches taken by each program, there is disagreement on critical statistical decisions made by each program. This disagreement however should not be an issue as Rasch analysis requires users to apply their own subjective analysis. While researchers might expect that Rasch performed on a large sample would be a stable, two authors who complete Rasch analysis of the PRWE found somewhat dissimilar findings. So, while some variations in results may be due to samples, this paper adds that some variation in findings may be software dependent