Evaluation of the optical switching characteristics of erbium-doped fibres for the development of a fibre Bragg grating sensor interrogator

A polling topology that employs optical switching based on the properties of erbium-doped fibres (EDFs) is used to interrogate an array of FBGs. The properties of the EDF are investigated in its pumped and un-pumped states and the EDFs’ switching properties are evaluated by comparing them with a high performance electronically controlled MEM optical switch. Potential advantages of the proposed technique are discussed. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

A Persistent Simulation Environment for Autonomous Systems

The age of Autonomous Unmanned Aircraft Systems (AUAS) is creating new challenges for the accreditation and certification requiring new standards, policies and procedures that sanction whether a UAS is safe to fly. Establishing a basis for certification of autonomous systems via research into trust and trustworthiness is the focus of Autonomy Teaming and TRAjectories for Complex Trusted Operational Reliability (ATTRACTOR), a new NASA Convergent Aeronautics Solution (CAS) project. Simulation Environments to test and evaluate AUAS decision making may be a low-cost solution to help certify that various AUAS systems are trustworthy enough to be allowed to fly in current general and commercial aviation airspace. NASA is working to build a peer-to-peer persistent simulation (P3 Sim) environment. The P3 Sim will be a Massively Multiplayer Online (MMO) environment were AUAS avatars can interact with a complex dynamic environment and each other. The focus of the effort is to provide AUAS researchers a low-cost intuitive testing environment that will aid training for and assessment of decisions made by autonomous systems such as AUAS. This presentation focuses on the design approach and challenges faced in development of the P3 Sim Environment is support of investigating trustworthiness of autonomous systems

Bounds on the Probability of Success of Postselected Non-linear Sign Shifts Implemented with Linear Optics

The fundamental gates of linear optics quantum computation are realized by using single photons sources, linear optics and photon counters. Success of these gates is conditioned on the pattern of photons detected without using feedback. Here it is shown that the maximum probability of success of these gates is typically strictly less than 1. For the one-mode non-linear sign shift, the probability of success is bounded by 1/2. For the conditional sign shift of two modes, this probability is bounded by 3/4. These bounds are still substantially larger than the highest probabilities shown to be achievable so far, which are 1/4 and 2/27, respectively.Comment: 6 page

Full Cell Mathematical Model of a MCFC

A theoretical model for the molten carbonate fuel cell was developed based on the three-phase homogeneous approach. Using this model, the contribution of different cell components to losses in cell performance has been studied. In general, at low current densities, the electrolyte matrix contributed to the major fraction of potential losses. Mass transfer effects became important at high current densities and were more prominent at the cathode. Electrolyte conductivity and cathode exchange current density seemed to play a limiting role in determining cell performance. Using the model, the maximum power density from a single cell for different cell thicknesses was determined

Effect of Time Reversal Symmetry Breaking on the Density of States in Small Superconducting Grains

We show that in ultra-small superconducting grains any concentration of magnetic impurities or infinitely small orbital effect of magnetic field leads to destruction of the hard gap in the tunneling density of states. Instead, though exponentially suppressed at low energies, the tunneling density of states exhibits the ``soft gap'' behavior, vanishing linearly with excitation energy, as the energy approaches zero.Comment: 4 pages, 1 eps figur

Theoretical Study of Physisorption of Nucleobases on Boron Nitride Nanotubes: A New Class of Hybrid Nano-Bio Materials

We investigate the adsorption of the nucleic acid bases, adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U) on the outer wall of a high curvature semiconducting single-walled boron nitride nanotube (BNNT) by first principles density functional theory calculations. The calculated binding energy shows the order: G>A\approxC\approxT\approxU implying that the interaction strength of the (high-curvature) BNNT with the nucleobases, G being an exception, is nearly the same. A higher binding energy for the G-BNNT conjugate appears to result from a stronger hybridization of the molecular orbitals of G and BNNT, since the charge transfer involved in the physisorption process is insignificant. A smaller energy gap predicted for the G-BNNT conjugate relative to that of the pristine BNNT may be useful in application of this class of biofunctional materials to the design of the next generation sensing devices.Comment: 17 pages 6 figure

Theory of I-V Characteristics of Magnetic Josephson Junctions

We analyze the electrical characteristics of a circuit consisting of a free thin-film magnetic layer and source and drain electrodes that have opposite magnetization orientations along the free magnet's two hard directions. We find that when the circuit's current exceeds a critical value there is a sudden resistance increase which can be large in relative terms if the currents to source or drain are strongly spin polarized and the free magnet is thin. This behavior can be partly understood in terms of a close analogy between the magnetic circuit and a Josephson junction

Deciding to Enrol in a Cancer Trial: A Systematic Review of Qualitative Studies.

Background:Clinical trials are essential for the advancement of cancer treatments; however, participation by patients is suboptimal. Currently, there is a lack of synthesized qualitative review evidence on the patient experience of trial entry from which to further develop decision support. The aim of this review is to synthesise literature reporting experiences of participants when deciding to enrol in a cancer clinical trial in order to inform practice. Methods:A systematic review and meta-synthesis of qualitative studies were conducted to describe the experiences of adult cancer patients who decided to enrol in a clinical trial of an anti-cancer treatment. Results:Forty studies met eligibility criteria for inclusion. Three themes were identified representing the overarching domains of experience when deciding to enrol in a cancer trial: 1) need for trial information; (2) trepidation towards participation; and (3) justifying the decision. The process of deciding to enrol in a clinical trial is one marked by uncertainty, emotional distress and driven by the search for a cure. Conclusion:Findings from this review show that decision support modelled by shared decision-making and the quality of a shared decision needs to be accompanied by tailored or personalised psychosocial and supportive care. Although the decision process bears similarities to theoretical processes outlined in decision-making frameworks, there are a lack of supportive interventions for cancer patients that are adapted to the clinical trial context. Theory-based interventions are urgently required to support the specific needs of patients deciding whether to participate in cancer trials

Implementation Strategies for Interventions Aiming to Increase Participation in Mail-Out Bowel Cancer Screening Programs: A Realist Review.

Background: Bowel cancer is the third most commonly diagnosed cancer and the third most common cause of cancer-related death, with 1,849,518 new cases of bowel diagnosed and 880,792 deaths reported globally in 2018 alone. Survival can be improved through early detection via national mail-out bowel cancer screening programs; however, participation remains low in many countries. Behavior change is therefore required to increase participation. This realist review aims to (a) identify the behavior change techniques (BCTs) used in each intervention, (b) understand the mechanisms of action (MoAs) responsible for the BCT effectiveness, and (c) apply a behavior change model to inform how MoAs can be combined to increase screening participation. Methods: We systematically reviewed the literature for interventions aiming to increase participation in mail-out bowel cancer screening. We used a four-stage realist synthesis approach whereby (1) interventions were extracted from each study; (2) BCTs applied in each intervention were identified and coded using the BCT Taxonomy-v1; (3) the Theory and Techniques Tool was used to link BCTs to their MoA; and (4) BCTs and MoAs were categorized according to their effectiveness and what Health Action Process Approach (HAPA) stage of change they would affect. Results: We identified 68 intervention trials using 26 unique BCTs and 13 MoAs to increase participation. Sixteen BCTs and 10 MoAs were identified within the interventions that successfully increased participation rates. Interventions targeting both stages of the HAPA model had a higher success rate (80%) than those targeting one stage of change (51%). When targeting only one stage, interventions targeting the volitional stage had a higher success rate (71%) than interventions targeting only the motivational stage of change (26%). Conclusion: Importantly, this review identified a suite of BCTs and MoAs effective for increasing participation in mail-out bowel cancer screening programs. With increased participation in bowel cancer screening leading to improved survival, our findings are key to informing the improvement of policy and interventions that aim to increase screening using specific strategies at key stages of health decision-making