Vector plotting as an indication of the approach to flutter

A binary flexure-torsion analysis was made to check theoretically a method for predicting flutter which depends on plotting vectorially the amplitudes of response relative to the exciting force and extracting the relevant damping rate. The results of this calculation are given in graphs both of the vector plots themselves and of the estimated damping rate against forward speed. The estimated damping rates are compared with calculated values. The method has the advantage that in a flight flutter test damping can be estimated from continuous excitation records: the method is an extension of the Kennedy and Pancu technique used in ground resonance testing

Quality of life in patients with intermittent claudication

© 2017, The Author(s). Background: Intermittent claudication (IC) is a common condition that causes pain in the lower limbs when walking and has been shown to severely impact the quality of life (QoL) of patients. The QoL is therefore often regarded as an important measure in clinical trials investigating intermittent claudication. To date, no consensus exits on the type of life questionnaire to be used. This review aims to examine the QoL questionnaires used in trials investigating peripheral arterial disease (PAD). Material and methods: A systematic review of randomised clinical trials including a primary analysis of QoL via questionnaire was performed. Trials involving patients with diagnosed PAD were included (either clinically or by questionnaire). Any trial which had QoL as the primary outcome data was included with no limit being placed on the type of questionnaire used. Results: The search yielded a total of 1845 articles of which 31 were deemed appropriate for inclusion in the review. In total, 14 different QoL questionnaires were used across 31 studies. Of the questionnaires 24.06% were missing at least one domain when reported in the results of the study. Mean standard deviation varied widely based on the domain reported, particularly within the SF36. Discussion: Despite previous recommendations for Europewide standardisation of quality of life assessment, to date no such tool exists. This review demonstrated that a number of different questionnaires remain in use, that their completion is often inadequate and that further evidence-based guidelines on QoL assessment are required to guide future research

Genetic and clinical contributions to cerebral palsy: A multi-variable analysis

All authors are contributors to the Australian Collaborative Cerebral Palsy Research Group The definitive version is available at www.wileyonlinelibrary.comAimThis study aims to examine single nucleotide polymorphism (SNP) associations with cerebral palsy in a multi-variable analysis adjusting for potential clinical confounders and to assess SNP-SNP and SNP-maternal infection interactions as contributors to cerebral palsy.MethodsA case control study including 587 children with cerebral palsy and 1154 control children without cerebral palsy. Thirty-nine candidate SNPs were genotyped in both mother and child. Data linkage to perinatal notes and cerebral palsy registers was performed with a supplementary maternal pregnancy questionnaire. History of known maternal infection during pregnancy was extracted from perinatal databases.ResultsBoth maternal and fetal carriage of inducible nitric oxide synthase SNP rs1137933 were significantly negatively associated with cerebral palsy in infants born at less than 32 weeks gestation after adjustment for potential clinical confounders and correction for multiple testing (odds ratio 0.55, 95% confidence interval 0.38-0.79; odds ratio 0.57, 95% confidence interval 0.4-0.82, respectively). Analysis did not show any statistically significant SNP-SNP or SNP-maternal infection interactions after correction for multiple testing.ConclusionsMaternal and child inducible nitric oxide synthase SNPs are associated with reduced risk of cerebral palsy in infants born very preterm. There was no evidence for statistically significant SNP-SNP or SNP-maternal infection interactions as modulators of cerebral palsy risk.Michael E O’Callaghan, Alastair H MacLennan, Catherine S Gibson, Gai L McMichael, Eric A Haan, Jessica L Broadbent, Peter A Baghurst, Paul N Goldwater, Gustaaf A Dekker and for the Australian Collaborative Cerebral Palsy Research Grou

The relationships between internal and external threat and right-wing attitudes: A three-wave longitudinal study

The interplay between threat and right-wing attitudes has received much research attention, but its longitudinal relationship has hardly been investigated. In this study, we investigated the longitudinal relationships between internal and external threat and right-wing attitudes using a cross-lagged design at three different time points in a large nationally representative sample (N = 800). We found evidence for bidirectional relationships. Higher levels of external threat were related to higher levels of Right-Wing Authoritarianism and to both the egalitarianism and dominance dimensions of Social Dominance Orientation at a later point in time. Conversely, higher levels of RWA were also related to increased perception of external threat later in time. Internal threat did not yield significant direct or indirect longitudinal relationships with right-wing attitudes. Theoretical and practical implications of these longitudinal effects are discussed

Percolation with Multiple Giant Clusters

We study the evolution of percolation with freezing. Specifically, we consider cluster formation via two competing processes: irreversible aggregation and freezing. We find that when the freezing rate exceeds a certain threshold, the percolation transition is suppressed. Below this threshold, the system undergoes a series of percolation transitions with multiple giant clusters ("gels") formed. Giant clusters are not self-averaging as their total number and their sizes fluctuate from realization to realization. The size distribution F_k, of frozen clusters of size k, has a universal tail, F_k ~ k^{-3}. We propose freezing as a practical mechanism for controlling the gel size.Comment: 4 pages, 3 figure

Lunar navigation study, sections 1 through 7 Final report, Jun. 1964 - May 1965

Lunar navigation analysis using passive nongyro, inertial navigation, and radio frequency technolog

Lunar navigation study, summary volume Final report, Jun. 1964 - May 1965

Lunar surface navigation and guidance study to implement lunar surface vehicle exploration mission

Universal crossing probability in anisotropic systems

Scale-invariant universal crossing probabilities are studied for critical anisotropic systems in two dimensions. For weakly anisotropic standard percolation in a rectangular-shaped system, Cardy's exact formula is generalized using a length-rescaling procedure. For strongly anisotropic systems in 1+1 dimensions, exact results are obtained for the random walk with absorbing boundary conditions, which can be considered as a linearized mean-field approximation for directed percolation. The bond and site directed percolation problem is itself studied numerically via Monte Carlo simulations on the diagonal square lattice with either free or periodic boundary conditions. A scale-invariant critical crossing probability is still obtained, which is a universal function of the effective aspect ratio r_eff=c r where r=L/t^z, z is the dynamical exponent and c is a non-universal amplitude.Comment: 7 pages, 4 figure