Conjugacy classes of p-cycles of type D in alternating groups

We classify the conjugacy classes of p-cycles of type D in alternating groups. This finishes the open cases in arXiv:0812.4628. We also determine all the subracks of those conjugacy classes which are not of type D.Comment: Second paragraph of subsection 2.2 rewritten. 4-th sentence of subsection 2.4 rewritten. More explanations added in Remark 2.4. Lemma 2.5 and Corollary 2.7 added. Appendix removed and put it as Remark 3.1. Remark 3.2 (former 3.1) reorganized. References: [Da], [EGSS], [H], [IS] added, [GPPS] removed. Communications in Algebra (2014

GNSS signal acquisition in the presence of sign transitions

The next generation of Global Navigation Satellite Systems (GNSS), such as Galileo [1] and GPS modernization [2], will use signals with equal code and bit periods, which will introduce a potential sign transition in each segment of the signal processed in the acquisition block. If FFT is used to perform the correlations a sign transition occurring within the integration time may cause a splitting of the main peak of the Cross Ambiguity Function (CAF) into two smaller lobes along the Doppler shift axis [3]. In this paper a method to overcome the possible impairments due to the lobe splitting is proposed and validated by simulation

Association of executive function impairment, history of falls and physical performance in older adults: A cross-sectional population-based study in Eastern France

To estimate: 1) the association between executive function (EF) impairment and falls; and 2) the association of EF impairment on tests of physical function used in the evaluation of fall risk.Cross-sectional study. Thirteen health examination centres in Eastern France. Four thousand four hundred and eighty one community-dwelling older adults without dementia aged 65 to 97 years (mean age 71.8 +/- 5.4, women 47.6%). Participants underwent a comprehensive medical assessment that included evaluations of EF using the Clock Drawing Test and of physical performance using the Timed Up & Go Test (TUG). Analysis used multivariable modified Poisson regression to evaluate the association between impaired EF and each of the fall outcomes (any fall, recurrent falls, fall-related injuries). Multivariable linear regression was used to evaluate the association between EF impairment and performance on the TUG and grip strength. EF impairment, assessed using the clock drawing test, was present in 24.9% of participants. EF impairment was independently associated with an increased risk of any fall (RR=1.13, 95% CI (1.03, 1.25)) and major soft tissue fall-related injury (RR= 2.42, 95% CI (1.47, 4.00)). Additionally, EF impairment was associated with worse performance on the TUG (p < 0.0001). EF impairment among older adults without dementia was highly prevalent and was independently associated with an increased risk for falls, fall-related injuries and with decreased physical function. The use of the Clock Drawing Test is an easy to administer measure of EF that can be used routinely in comprehensive fall risk evaluations

A new automated strategy for optimizing inclined interplanetary low-thrust trajectories

This study proposes a new automated strategy for designing and optimizing three-dimensional interplanetary low-thrust (LT) trajectories. The method formulates the design as a hybrid optimal control problem and solves it using a two-step approach. In Step 1, a three-dimensional model based on generalized logarithmic spirals is used with heuristics in combination with a gradient-based solver to perform an automated multi-objective global search of trajectories and optimize for parameters defining the spirals, the launch date, as well as the number, sequence and configuration of the planetary flybys. In Step 2, candidate solutions from Step 1 are refined by further optimization with a direct method. Results show that, compared to similar algorithms based on two-dimensional models, the strategy implemented in Step 1 leads to better estimates of the optimal trajectories, especially when the orbits of the involved bodies are inclined with respect to the ecliptic plane. The proposed approximate method (Step 1) yields better agreement with high-fidelity solutions (Step 2) in terms of launch, flyby and arrival dates, in-plane and out-of-plane average LT accelerations and propellant consumption, leading to improved convergence when the Step 1 trajectories are employed to initiate the search in Step 2

Cognitive Effects of Vitamin D Supplementation in Older Outpatients Visiting a Memory Clinic: A Pre–Post Study

International audienc

Geosynchronous inclined orbits for high-latitude communications

We present and discuss a solution to the growing demand for satellite telecommunication coverage in the high-latitude geographical regions (beyond 55◦N), where the signal from geostationary satellites is limited or unavailable. We focus on the dynamical issues associated to the design, the coverage, the maintenance and the disposal of a set of orbits selected for the purpose. Specifically, we identify a group of highly inclined, moderately eccentric geosynchronous orbits derived from the Tundra orbit (geosynchronous, eccentric and critically inclined). Continuous coverage can be guaranteed by a constellation of three satellites in equally spaced planes and suitably phased. By means of a highprecision model of the terrestrial gravity field and the relevant environmental perturbations, we study the evolution of these orbits. The effects of the different perturbations on the ground track (which is more important for coverage than the orbital elements themselves) are isolated and analyzed. The physical model and the numerical setup are optimized with respect to computing time and accuracy. We show that, in order to maintain the ground track unchanged, the key parameters are the orbital period and the argument of perigee. Furthermore, corrections to the right ascension of the ascending node are needed in order to preserve the relative orientation of the orbital planes. A station-keeping strategy that minimizes propellant consumption is then devised, and comparisons are made between the cost of a solution based on impulsive maneuvers and one with continuous thrust. Finally, the issue of end-of-life disposal is discussed

In Situ Thermal Generation of Silver Nanoparticles in 3D Printed Polymeric Structures

Polymer nanocomposites have always attracted the interest of researchers and industry because of their potential combination of properties from both the nanofillers and the hosting matrix. Gathering nanomaterials and 3D printing could offer clear advantages and numerous new opportunities in several application fields. Embedding nanofillers in a polymeric matrix could improve the final material properties but usually the printing process gets more difficult. Considering this drawback, in this paper we propose a method to obtain polymer nanocomposites by in situ generation of nanoparticles after the printing process. 3D structures were fabricated through a Digital Light Processing (DLP) system by disolving metal salts in the starting liquid formulation. The 3D fabrication is followed by a thermal treatment in order to induce in situ generation of metal nanoparticles (NPs) in the polymer matrix. Comprehensive studies were systematically performed on the thermo-mechanical characteristics, morphology and electrical properties of the 3D printed nanocomposites