ANALYTICAL INVESTIGATION AND PREDICTION OF SPIN AND RECOVERY CHARACTERISTICS OF THE NORTH AMERICAN X-15 AIRPLANE

Spin and recovery characteristics of north american x-15 aircraf

Long-Tailed Trapping Times and Levy Flights in a Self-Organized Critical Granular System

We present a continuous time random walk model for the scale-invariant transport found in a self-organized critical rice pile [Christensen et al., Phys. Rev. Lett. 77, 107 (1996)]. From our analytical results it is shown that the dynamics of the experiment can be explained in terms of L\'evy flights for the grains and a long-tailed distribution of trapping times. Scaling relations for the exponents of these distributions are obtained. The predicted microscopic behavior is confirmed by means of a cellular automaton model.Comment: 4 pages, RevTex, includes 3 PostScript figures, submitted to Phys. Rev. Let

Participatory research emergent recommendations for researchers and academic institutions: a rapid scoping review

In recent years, a range of academic disciplines have emphasized the potential benefits of prioritizing meaningful engagement with individuals and communities who have lived and have living experience with the topics, phenomena and problems researchers seek to study. In March 2022, we were asked to produce a paper to inform a university workshop and training materials to help students and faculty engage with participatory methods. In turn, we conducted a rapid scoping review of reviews to document key recommendations relating to methodology, logistics and ethics within the various modes of participatory research. Searches were conducted in Web of Science, SCOPUS, ProQuest, Pub Med, OVID (including Medline, PschyInfo/EMBASE, APAPsych) to identify published academic reviews (e.g., systematic, scoping, literature reviews and evidence gap maps), for best practices relating to participatory research. This approach drew out aggregated best practices and lessons learned across many primary studies and increased the speed of the review. From 276 studies imported for screening, 43 full-text studies were assessed for eligibility and 28 were deemed relevant for full inclusion. Results are presented as: 1) participatory research recommendations for researchers; and 2) participatory research recommendations for academic institutions. Three sub-themes emerged within the context of suggestions for researchers engaging with participatory methods: 1) early-stage considerations for study design and planning; 2) conducting the research; and 3) dissemination and knowledge exchange. This rapid scoping review highlights key recommendations for researchers interested in using participatory approaches in their own research, and for academic and institutional stakeholders who aim to support these practices

Electrical transport and percolation in magnetoresistive manganite / insulating oxide composites: case of La0.7Ca0.3MnO3 / Mn3O4

We report the results of electrical resistivity measurements carried out on well-sintered La0.7Ca0.3MnO3 / Mn3O4 composite samples with almost constant composition of the magnetoresistive manganite phase (La0.7Ca0.3MnO3). A percolation threshold (fc) occurs when the La0.7Ca0.3MnO3 volume fraction is ~ 0.19. The dependence of the electrical resistivity as a function of La0.7Ca0.3MnO3 volume fraction (fLCMO) can be described by percolation-like phenomenological equations. Fitting the conducting regime (fLCMO > fc) by the percolation power law returns a critical exponent t value of 2.0 +/- 0.2 at room temperature and 2.6 +/-0.2 at 5 K. The increase of t is ascribed to the influence of the grain boundaries on the electrical conduction process at low temperature.Comment: 7 pages, 3 figures, accepted for publication in Phys. Rev.

Levy flights from a continuous-time process

The Levy-flight dynamics can stem from simple random walks in a system whose operational time (number of steps n) typically grows superlinearly with physical time t. Thus, this processes is a kind of continuous-time random walks (CTRW), dual to usual Scher-Montroll model, in which $n$ grows sublinearly with t. The models in which Levy-flights emerge due to a temporal subordination let easily discuss the response of a random walker to a weak outer force, which is shown to be nonlinear. On the other hand, the relaxation of en ensemble of such walkers in a harmonic potential follows a simple exponential pattern and leads to a normal Boltzmann distribution. The mixed models, describing normal CTRW in superlinear operational time and Levy-flights under the operational time of subdiffusive CTRW lead to paradoxical diffusive behavior, similar to the one found in transport on polymer chains. The relaxation to the Boltzmann distribution in such models is slow and asymptotically follows a power-law

Fractional diffusion in periodic potentials

Fractional, anomalous diffusion in space-periodic potentials is investigated. The analytical solution for the effective, fractional diffusion coefficient in an arbitrary periodic potential is obtained in closed form in terms of two quadratures. This theoretical result is corroborated by numerical simulations for different shapes of the periodic potential. Normal and fractional spreading processes are contrasted via their time evolution of the corresponding probability densities in state space. While there are distinct differences occurring at small evolution times, a re-scaling of time yields a mutual matching between the long-time behaviors of normal and fractional diffusion