Teleseismic tomography: Equation one is wrong

ABSTRACT Seismic tomography methods that use waves originating outside the volume being studied are subject to bias caused by unknown structure outside this volume. The bias is of the same mathematical order and similar magnitude as the local-structure effects being studied; failure to account for it can significantly corrupt derived structural models. This bias can be eliminated by adding to the inverse problem three unknown parameters specifying the direction and time for each incident wave, a procedure analogous to solving for event locations in local-earthquake and whole-mantle tomography. The forward problem is particularly simple: The first-order change in the arrival time at an observation point resulting from a perturbation to the incident-wave direction and time equals the change in the time of the perturbed incident wave at the point where the unperturbed ray entered the study volume. This consequence of Fermat’s principle apparently has not previously been recognized. Published teleseismic tomography models probably contain significant artifacts and need to be recomputed using the more complete theory.

Nonlinear Viscoelastic-Plastic Creep Model of Rock Based on Fractional Calculus

A rock creep constitutive model is the core content of rock rheological mechanics theory and is of great significance for studying the long-term stability of engineering. Most of the creep models constructed in previous studies have complex types and many parameters. Based on fractional calculus theory, this paper explores the creep curve characteristics of the creep elements with the fractional order change, constructs a nonlinear viscoelastic-plastic creep model of rock based on fractional calculus, and deduces the creep constitutive equation. By using a user-defined function fitting tool of the Origin software and the Levenberg–Marquardt optimization algorithm, the creep test data are fitted and compared. The fitting curve is in good agreement with the experimental data, which shows the rationality and applicability of the proposed nonlinear viscoelastic-plastic creep model. Through sensitivity analysis of the fractional order β2 and viscoelastic coefficient ξ2, the influence of these creep parameters on rock creep is clarified. The research results show that the nonlinear viscoelastic-plastic creep model of rock based on fractional calculus constructed in this paper can well describe the creep characteristics of rock, and this model has certain theoretical significance and engineering application value for long-term engineering stability research.

Gender Equity in the Marketing Academy: From Performative to Institutional Allyship

The fair treatment of women in the workplace, where they experience both opportunities and constraints, has been on and off higher education agendas for decades. Yet, institutionalised gendered constraints still shape the careers of female academics, including those in the marketing academy, resulting in disrupted or obstacle-heavy career journeys and the underrepresentation of women in senior positions. Furthermore, progress towards gender equity is hampered by institutional resistance to change, favouring performative rather than genuine and transformational institutional allyship. We draw upon personal experiences, recollections and anecdotes garnered over the years – synthesised with literature – to examine systemic gendered constraints within our collective career span. We propose institutional allyship as the intentional efforts needed by the marketing academy to address systemic and structural gender inequities and achieve second-order change by integrating gender equity outcomes throughout organisational decision-making. Specifically, we suggest nominated actions within a Gender Equity and Inclusion Charter for the Australian and New Zealand Marketing Academy (ANZMAC) and its member universities as a first step.

Dataset-adaptive minimizer order reduces memory usage in k-mer counting

The rapid, continuous growth of deep sequencing experiments requires development and improvement of many bioinformatics applications for analysis of large sequencing datasets, including k-mer counting and assembly. Several applications reduce RAM usage by binning sequences. Binning is done by employing minimizer schemes, which rely on a specific order of the minimizers. It has been demonstrated that the choice of the order has a major impact on the performance of the applications. Here we introduce a method for tailoring the order to the dataset. Our method repeatedly samples the dataset and modifies the order so as to flatten the k-mer load distribution across minimizers. We integrated our method into Gerbil, a state-of-the-art memory efficient k-mer counter, and were able to reduce its memory footprint by 50% or more for large k, with only minor increase in runtime. Our tests also showed that the orders produced by our method produced superior results when transferred across datasets from the same species, with little or no order change. This enables memory reduction with essentially no increase in runtime.

Slow oxidation of magnetite nanoparticles elucidates the limits of the Verwey transition

Magnetite (Fe3O4) is of fundamental importance for the Verwey transition near TV = 125 K, below which a complex lattice distortion and electron orders occur. The Verwey transition is suppressed by chemical doping effects giving rise to well-documented first and second-order regimes, but the origin of the order change is unclear. Here, we show that slow oxidation of monodisperse Fe3O4 nanoparticles leads to an intriguing variation of the Verwey transition: an initial drop of TV to a minimum at 70 K after 75 days and a followed recovery to 95 K after 160 days. A physical model based on both doping and doping-gradient effects accounts quantitatively for this evolution between inhomogeneous to homogeneous doping regimes. This work demonstrates that slow oxidation of nanoparticles can give exquisite control and separation of homogeneous and inhomogeneous doping effects on the Verwey transition and offers opportunities for similar insights into complex electronic and magnetic phase transitions in other materials.

Expanding God’s Redemptive Fractal: Spirit-Centered Counseling and the Transformative Wisdom of Jesus

Using the image of a fractal, a Spirit-centered approach to counseling is proposed that conceptualizes the Spirit’s activity as seeking to replicate the patterns of God’s redemptive story throughout creation by facilitating deep second-order change. Involving an epistemological shift from ways of knowing shaped by the conventional wisdom of culture to a renewed mind grounded in the transformative wisdom of Jesus, this deep change is explored from the perspectives of science and Scripture. Integrating findings from systems theory with the ministry and message of Jesus, this approach to counseling emphasizes relational premises and values believed to be characteristic of the mind of the Spirit. Defined as the capacity to know and see in ways that are consistent with the passion and purposes of God, cultivating the mind of the Spirit is viewed as the essence of Spirit-centered counseling. Presumed to be seen most clearly in the life of Jesus, this model focuses on his distinctive way of knowing and seeing by examining what can be learned about the epistemological facets of perception and meaning-making when comparing his Way with the patterns of this world. It is proposed that Spirit-centered counseling is guided by the premises and patterns contained in Jesus’ transformative wisdom.

On a Memristor-Based Hyperchaotic Circuit in the Context of Nonlocal and Nonsingular Kernel Fractional Operator

Memristor is a nonlinear and memory element that has a future of replacing resistors for nonlinear circuit computation. It exhibits complex properties such as chaos and hyperchaos. A five-dimensional memristor-based circuit in the context of a nonlocal and nonsingular fractional derivative is considered for analysis. The Banach fixed point theorem and contraction principle are utilized to verify the existence and uniqueness of the solution of the five-dimensional system. A numerical method developed by Toufik and Atangana is used to get approximate solutions of the system. Local stability analysis is examined using the Matignon fractional-order stability criteria, and it is shown that the trivial equilibrium point is unstable. The Lyapunov exponents for different fractional orders exposed that the nature of the five-dimensional fractional-order system is hyperchaotic. Bifurcation diagrams are obtained by varying the fractional order and two of the parameters in the model. It is shown using phase-space portraits and time-series orbit figures that the system is sensitive to derivative order change, parameter change, and small initial condition change. Master-slave synchronization of the hyperchaotic system was established, the error analysis was made, and the simulation results of the synchronized systems revealed a strong correlation among themselves.

Effectiveness of On-Court Resistive Warm-Ups on Change of Direction Speed and Smash Velocity during a Simulated Badminton Match Play in Well-Trained Players

In badminton, power production can be enhanced through the fundamental practice of a dynamic warm-up with resistance conditioning activity to induce a post-activation performance enhancement (PAPE) effect. The use of heavy resistance exercise in the form of heavy weights to induce PAPE during competition is not logistically practical in the badminton arena. Thus, there is a need to investigate the use of easily available alternative preconditioning stimuli to induce a similar potentiating effect in badminton-specific performance. This study adopted a repeated-measures design of three warm-up conditions: control (CON), weighted wearable resistance (WWR), and resistance band variable resistance (BVR). Fourteen badminton players from the national training squad (11 males, 3 females, age 18 ± 1 y) completed the experimental sessions in random order. Change of direction speed (CODS) and smash velocity (SV) tests were performed at five timepoints—baseline test after the warm-up and at the end of each of the four exercise blocks of a simulated match play protocol. CODS was significantly faster under the two resistance warm-up conditions (WWR and BVR) compared to the CON condition at baseline (−0.2 s ± 0.39 and −0.2 s ± 0.46, p = 0.001 and 0.03, g = 0.47 and 0.40, respectively), but there were no differences at the other timepoints (all p > 0.05). SV was significantly faster for all the four exercise blocks than at baseline under all three warm-up conditions (p = 0.02), but there were no differences in SV between the three warm-up conditions across all the five measured timepoints (p = 0.15). In conclusion, implementing resistance (~10% body weight) in sport-specific plyometric exercises using WWR or BVR during warm-up routines may induce PAPE effects on the change of direction speed but not smash velocity, in well-trained badminton players, as compared with the same warm-up exercises using bodyweight (i.e., CON condition). The positive effects of CODS were, however, observed only at the start of the match and possibly lasted for up to between 5 and 10 min of match play.

Consequences of development of the sharing economy in tourism for cities – theory and examples

The purpose of the article is to identify the impacts generated in the cities by the sharing economy in tourism and the presentation of solutions appearing due to sharing economy development and implementation in particular cities. Contemporary cities are functioning in extremely dynamic conditions that are difficult to predict. In view of the globalising economy, progressive urbanisation, rapid changes in information and communication technologies, as well as social demographic, geopolitical and economic changes, new problems appear and solutions to them have to be implemented by cities. One of these phenomena that are relatively new and fast growing, and influence development of cities, is sharing economy (SE) in tourism. The greatest concern of the city authorities is fast and unrestrained development of services through global platforms in the accommodation and passenger transport industry, and the powerful global leaders of these markets – Airbnb and Uber have become very important partners for local governments, but also difficult ones. On the bases of extended literature review embracing scientific sources and industry reports it can be visible, that actions taken by the local authorities tend to be reactive not systematic and concentrated only on solving isolated current problems. It is postulated though that development of SE should be perceived in a way described by Hall (1994) as a third-order change. Several suggestions for future scientific research are also presented.