Application of ARCHIMEDES in Three Dimensions and to Solid Mechanics

ARCHIMEDES is a computerized learning system that has helped Syracuse University students overcome the challenges of Engineering Statics since 2009. Its success has motivated application of ARCHIMEDES to three dimensional problems and to problems in Solid Mechanics. Other learning software was investigated before seven Solid Mechanics problems were written for ARCHIMEDES. A 3D graphical interface was developed and evaluated by a field test of student volunteers. Student preferences for various features in 3D learning software were obtained. It is clear from student responses that having a 3D scene to manipulate improves visualization of the problem, mitigating the ambiguity of a textbook problem’s graphic

Application of ARCHIMEDES in Three Dimensions and to Solid Mechanics

ARCHIMEDES is a computerized learning system that has helped Syracuse University students overcome the challenges of Engineering Statics since 2009. Its success has motivated application of ARCHIMEDES to three dimensional problems and to problems in Solid Mechanics. Other learning software was investigated before seven Solid Mechanics problems were written for ARCHIMEDES. A 3D graphical interface was developed and evaluated by a field test of student volunteers. Student preferences for various features in 3D learning software were obtained. It is clear from student responses that having a 3D scene to manipulate improves visualization of the problem, mitigating the ambiguity of a textbook problem’s graphic

Monopolizing force?: police legitimacy and public attitudes towards the acceptability of violence

Why do people believe that violence is acceptable? In this paper we study people’s normative beliefs about the acceptability of violence to achieve social control (as a substitute for the police, for self-protection and the resolution of disputes) and social change (through violent protests and acts to achieve political goals). Addressing attitudes towards violence among young men from various ethnic minority communities in London, we find that procedural justice is strongly correlated with police legitimacy, and that positive judgments about police legitimacy are associated with more negative views about the use of violence. We conclude with the idea that police legitimacy has an additional, hitherto unrecognized, empirical property – by constituting the belief that the police monopolise rightful force in society, legitimacy has a ‘crowding out’ effect on positive views of private violence

The Moral Obligation to Prioritize Research Into Deep Brain Stimulation Over Brain Lesioning Procedures for Severe Enduring Anorexia Nervosa

Deep Brain Stimulation is currently being investigated as an experimental treatment for patients suffering from treatment-refractory AN, with an increasing number of case reports and small-scale trials published. Although still at an exploratory and experimental stage, initial results have been promising. Despite the risks associated with an invasive neurosurgical procedure and the long-term implantation of a foreign body, DBS has a number of advantageous features for patients with SE-AN. Stimulation can be fine-tuned to the specific needs of the particular patient, is relatively reversible, and the technique also allows for the crucial issue of investigating and comparing the effects of different neural targets. However, at a time when DBS is emerging as a promising investigational treatment modality for AN, lesioning procedures in psychiatry are having a renaissance. Of concern it has been argued that the two kinds of interventions should instead be understood as rivaling, yet “mutually enriching paradigms” despite the fact that lesioning the brain is irreversible and there is no evidence base for an effective target in AN. We argue that lesioning procedures in AN are unethical at this stage of knowledge and seriously problematic for this patient group, for whom self-control is particularly central to wellbeing. They pose a greater risk of major harms that cannot justify ethical equipoise, despite the apparent superiority in reduced short term surgical harms and lower cost

Autoantibody-Based Diagnostic Biomarkers: Technological Approaches to Discovery and Validation

Autoantibodies produced against self-antigens, or ‘autoantigens’, result from a loss of self-tolerance triggered by genetic and/or environmental factors which induce the immune system to attack the host’s own cells, resulting in a condition referred to as autoimmunity. In classic autoimmune diseases, it is well established that the pathology relates directly to the autoantibodies. However, it is increasingly recognised that autoantibodies are also found in many other disease areas, including cancers, cardiovascular and neurodegenerative diseases, as well infectious diseases such as malaria, albeit in such diseases it is unclear whether the autoantibodies play a direct role in the pathology or whether they are merely symptomatic of disease. Irrespective of whether they are causative or symptomatic of specific diseases though, there is increasing interest globally in exploring the clinical potential of circulating autoantibodies as diagnostic biomarkers. This chapter provides an overview of the diagnostic utility of autoantibody biomarkers in a range of disease areas and discusses their potential utility in disease staging, treatment monitoring and in prediction of immune-related adverse events. It also provides an overview of traditional and contemporary technological approaches to autoantibody biomarker discovery and validation, focusing on protein microarrays that are ideally suited to this important area of research

Empirical Validation of a Model for Predicting Students' Sense of Belonging and School Engagement as a Function of Classroom Management Practices

Over the last two decades, several studies have overlooked at-school belonging and engagement, two dimensions that are associated with several positive outcomes. However, the relative influence that contexts and interventions may have on these components has received much less attention. In this study, school belonging and engagement were examined as a function of the implementation and application of classroom rules. The study took place in two Moroccan schools, and participants were 238 students from 9th grade (101 boys, 137 girls; Mage = 15.1) living in the cities of Casablanca and Témara. They all completed a questionnaire that allowed to measure their belonging and engagement in conjunction with the manner in which rules are implemented and applied. Correlational and structural equation modeling methods were used to analyze the aforementioned relationships. Results showed that implementation of classroom rules had a positive effect on school belonging, which, in turn, had a positive effect on school engagement. These results indicated the need to conduct further empirical research to measure the contribution of classroom management practices on school belonging

Timed Lossy Channel Systems

Lossy channel systems are a classical model with applications ranging from the modeling of communication protocols to programs running on weak memory models. All existing work assume that messages traveling inside the channels are picked from a finite alphabet. In this paper, we extend the model by assuming that each message is equipped with a clock representing the age of the message, thus obtaining the model of Timed Lossy Channel Systems (TLCS). The main contribution of the paper is to show that the control state reachability problem is decidable for TLCS

Low-Thrust Many-Revolution Trajectory Optimization

This dissertation presents a method for optimizing the trajectories of spacecraft that use low-thrust propulsion to maneuver through high counts of orbital revolutions. The proposed method is to discretize the trajectory and control schedule with respect to an orbit anomaly and perform the optimization with differential dynamic programming (DDP). The change of variable from time to orbit anomaly is accomplished by a Sundman transformation to the spacecraft equations of motion. Sundman transformations to each of the true, mean and eccentric anomalies are leveraged for fuel-optimal geocentric transfers up to 2000 revolutions. The approach is shown to be amenable to the inclusion of perturbations in the dynamic model, specifically aspherical gravity and third-body perturbations, and is improved upon through the use of modified equinoctial elements. An assessment of computational performance shows the importance of parallelization but that a single, multi-core processor is effective. The computational efficiency facilitates the generation of fuel versus time of flight trade-offs within a matter of hours. Many-revolution trajectories are characteristic of orbit transfers accomplished by solar electric propulsion about planetary bodies. Methods for modeling the effect of solar eclipses on the power available to the spacecraft and constraining eclipse durations are also presented. The logistic sunlight fraction is introduced as a coefficient that scales the computed power available by the fraction of sunlight available. The logistic sunlight fraction and Sundman-transformed DDP are used to analyze transfers from low-Earth orbit to geostationary orbit. The analysis includes a systematic approach to estimating the Pareto front of fuel versus time of flight.In addition to addressing many-revolution trajectories, this dissertation advances the utility of DDP in the three-body problem. Fuel-optimal transfers are presented in the Earth-Moon circular restricted three-body problem between distant retrograde orbits, between Lyapunov orbits and between Halo orbits. Those include mechanisms for varying the time of flight and the insertion point onto a target orbit. A multi-phase DDP approach enables initial guesses to be constructed from discontinuous trajectory segments. DDP is shown to leverage the system dynamics to find a heteroclinic connection between Lyapunov orbits, which is facilitated by the multi-phase approach

Shape Analysis via Monotonic Abstraction

We propose a new formalism for reasoning about dynamic memory heaps, using monotonic abstraction and symbolic backward reachability analysis. We represent the heaps as graphs, and introduce an ordering on these graphs. This enables us to represent the violation of a given safety property as the reachability of a finitely representable set of bad graphs. We also describe how to symbolically compute the reachable states in the transition system induced by a program

Scalable heating-up synthesis of monodisperse Cu2ZnSnS4 nanocrystals

Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals (NCs), with quasi spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%