359 research outputs found
Consolidation of data base for Army generalized missile model
Data from plume interaction tests, nose mounted canard configuration tests, and high angle of attack tests on the Army Generalized Missile model are consolidated in a computer program which makes them readily accessible for plotting, listing, and evaluation. The program is written in FORTRAN and will run on an ordinary minicomputer. It has the capability of retrieving any coefficient from the existing DATAMAN tapes and displaying it in tabular or plotted form. Comparisons of data taken in several wind tunnels and of data with the predictions of Program MISSILE2 are also presented
Application of advanced computational procedures for modeling solar-wind interactions with Venus: Theory and computer code
Computational procedures are developed and applied to the prediction of solar wind interaction with nonmagnetic terrestrial planet atmospheres, with particular emphasis to Venus. The theoretical method is based on a single fluid, steady, dissipationless, magnetohydrodynamic continuum model, and is appropriate for the calculation of axisymmetric, supersonic, super-Alfvenic solar wind flow past terrestrial planets. The procedures, which consist of finite difference codes to determine the gasdynamic properties and a variety of special purpose codes to determine the frozen magnetic field, streamlines, contours, plots, etc. of the flow, are organized into one computational program. Theoretical results based upon these procedures are reported for a wide variety of solar wind conditions and ionopause obstacle shapes. Plasma and magnetic field comparisons in the ionosheath are also provided with actual spacecraft data obtained by the Pioneer Venus Orbiter
Indirect Inference for Time Series Using the Empirical Characteristic Function and Control Variates
We estimate the parameter of a stationary time series process by minimizing
the integrated weighted mean squared error between the empirical and simulated
characteristic function, when the true characteristic functions cannot be
explicitly computed. Motivated by Indirect Inference, we use a Monte Carlo
approximation of the characteristic function based on iid simulated blocks. As
a classical variance reduction technique, we propose the use of control
variates for reducing the variance of this Monte Carlo approximation. These two
approximations yield two new estimators that are applicable to a large class of
time series processes. We show consistency and asymptotic normality of the
parameter estimators under strong mixing, moment conditions, and smoothness of
the simulated blocks with respect to its parameter. In a simulation study we
show the good performance of these new simulation based estimators, and the
superiority of the control variates based estimator for Poisson driven time
series of counts.Comment: 38 pages, 2 figure
Design of the Magnet System of the Neutron Decay Facility PERC
The PERC (Proton and Electron Radiation Channel) facility is currently under
construction at the research reactor FRM II, Garching. It will serve as an
intense and clean source of electrons and protons from neutron beta decay for
precision studies. It aims to contribute to the determination of the
Cabibbo-Kobayashi-Maskawa quark-mixing element from neutron decay data
and to search for new physics via new effective couplings. PERC's central
component is a 12m long superconducting magnet system. It hosts an 8m long
decay region in a uniform field. An additional high-field region selects the
phase space of electrons and protons which can reach the detectors and largely
improves systematic uncertainties. We discuss the design of the magnet system
and the resulting properties of the magnetic field.Comment: Proceedings of the International Workshop on Particle Physics at
Neutron Sources PPNS 2018, Grenoble, France, May 24-26, 201
Convergence of the stochastic Euler scheme for locally Lipschitz coefficients
Stochastic differential equations are often simulated with the Monte Carlo
Euler method. Convergence of this method is well understood in the case of
globally Lipschitz continuous coefficients of the stochastic differential
equation. The important case of superlinearly growing coefficients, however,
has remained an open question. The main difficulty is that numerically weak
convergence fails to hold in many cases of superlinearly growing coefficients.
In this paper we overcome this difficulty and establish convergence of the
Monte Carlo Euler method for a large class of one-dimensional stochastic
differential equations whose drift functions have at most polynomial growth.Comment: Published at http://www.springerlink.com/content/g076w80730811vv3 in
the Foundations of Computational Mathematics 201
More than sense of place? Exploring the emotional dimension of rural tourism experiences
It is widely suggested that participation in rural tourism is underpinned by a sense of rural place or “rurality”. However, although nature and the countryside have long been recognised as a source of spiritual or emotional fulfilment, few have explored the extent to which tourism, itself often claimed to be a sacred experience, offers an emotional/spiritual dimension in the rural context. This paper addresses that literature gap. Using in-depth interviews with rural tourists in the English Lake District, it explores the extent to which, within respondents’ individual understanding of spirituality, a relationship exists between sense of place and deeper, emotional experiences and, especially, whether participation in rural tourism may induce spiritual or emotional responses. The research revealed that all respondents felt a strong attachment to the Lake District; similarly, and irrespective of their openness to spirituality, engaging in rural tourism activities resulted in highly emotive experiences for all respondents, the description/interpretation of such experiences being determined by individual “beliefs”. However, sense of place was not a prerequisite to emotional or spiritual experiences. Being in and engaging with the landscape � effectively becoming part of it � especially through physical activity is fundamental to emotional responses
Synovial sarcomas usually metastasize after >5 years: a multicenter retrospective analysis with minimum follow-up of 10 years for survivors
In SS, metastases develop late with high mortality. Patients with SS should be followed for >10 year
Complex relationships among personality traits, job characteristics, and work behaviors
The aim of the study was to investigate the additive, mediating, and moderating effects of personality traits and job characteristics on work behaviors. Job applicants (N = 161) completed personality questionnaires measuring extraversion, neuroticism, achievement motivation, and experience seeking. One and a half years later, supervisors rated the applicants' job performance, and the job incumbents completed questionnaires about skill variety, autonomy, and feedback, work stress, job satisfaction, work self-efficacy, and propensity to leave. LISREL was used to test 15 hypotheses. Perceived feedback mediated the relationship between achievement motivation and job performance. Extraversion predicted work self-efficacy and job satisfaction. Work stress mediated the relationship between neuroticism and job satisfaction. Job satisfaction and experience seeking were related to propensity to leave. Autonomy, skill variety, and feedback were related to job satisfaction
Staged treatment of a comminuted femoral fracture with Masquelet technique and 3D printed reposition guides.
Background
Comminuted femoral fractures pose a challenge to the trauma surgeon due to the absence of bony references during surgery. Therefore, malalignment of length and axis can occur and necessitate revision surgery. During the last decade, 3D-planning has evolved as a surgical aid in difficult cases.
Case report
An 18-year-old male patient suffered a polytrauma following a motorcycle accident. This report is about the treatment of a 3rd degree open and comminuted fracture of the left distal femur. The fracture was treated with Masquelet's two-staged technique. With the intent of avoiding malalignment, the second stage surgery was performed with the aid of 3D-planned reduction guides. Despite complex fracture pattern, complete fracture union was achieved with acceptable final alignment (side-to-side comparison of length, axis and femoral torsion).
Conclusion
In this case, performing Masquelet's two-staged surgery with the aid of 3D-printed reposition guides yielded favorable results in regards to rotational malalignment. The malrotation of the femur was reduced after the second operation to a clinically acceptable side-to-side difference (10°). This technique remains technically challenging due to soft tissue tension and limited possibility of soft tissue release
VEGF incorporated into calcium phosphate ceramics promotes vascularisation and bone formation in vivo
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