Optimal Offline and Competitive Online Strategies for Transmitter-Receiver Energy Harvesting

Transmitter-receiver energy harvesting model is assumed, where both the transmitter and receiver are powered by random energy source. Given a fixed number of bits, the problem is to find the optimal transmission power profile at the transmitter and ON-OFF profile at the receiver to minimize the transmission time. Structure of the optimal offline strategy is derived together with an optimal offline policy. An online policy with competitive ratio of strictly less than two is also derived

Percutaneous Radiofrequency Lesioning of the Suprascapular Nerve for the Management of Chronic Shoulder Pain: A Case Series

Purpose: The objective of this study was to retrospectively evaluate the analgesic effects of continuous radiofrequency lesioning of the suprascapular nerve (SSN) for chronic shoulder pain. The authors sought to obtain insight into the time-sensitive analgesic success and complications of this therapy. Patients and methods: This study was a retrospective case series involving patients with unremitting shoulder pain that had lasted for at least 12 months. Patients were selected if they showed a reduction of at least 50% in pain intensity during the anesthetic phase after SSN block, no additional motor weakness of the shoulder, and pain relief lasting for less than 2 months after separate treatments of the SSN with depot corticosteroids and pulsed radiofrequency. Nine patients were referred to the Arnold Pain Management Center. Of these nine patients, six patients who had significant chronic shoulder pain unresponsive to oral medications and intra-articular injections and who were not considered surgical candidates were selected. These patients were treated with a single radiofrequency lesion of the SSN at 80$^\circ$C for 60 seconds. The primary outcome was a reduction in pain intensity by 50%, as determined by the numeric rating scale, and duration of this effect. The secondary outcome was improvement in either the passive or the active range of motion (ROM). Patients were also monitored for adverse effects such as weakness or increased pain. Results: The pooled mean numeric rating scale score before the procedure was 7.2 $\pm$ 1.2; this fell to 3.0 $\pm$ 0.9 at 5–7 weeks post procedure. The duration of pain relief ranged from 3 to 18 months, and all patients underwent at least one additional treatment. The change in baseline ROM improved from an average of 60$^\circ$ $\pm$ 28$^\circ$ (flexion) and 58$^\circ$ $\pm$ 28$^\circ$ (abduction) to 99$^\circ$ $\pm$ 46$^\circ$ (flexion) and 107$^\circ$ $\pm$ 39$^\circ$ (abduction). No adverse side effects were observed. Conclusion: Continuous radiofrequency lesioning of the SSN seems to be an effective treatment for chronic shoulder pain. There can be improved ROM of the shoulder following this treatment. More formal, controlled studies are required to confirm these observations

Using the economic surplus model to measure potential returns to international livestock research. The case of trypanosomosis vaccine research

This study illustrates how productivity impacts resulting from livestock research can be measured using a herd simulation model, how the results of this model can be extended spatially using geographic information systems (GIS) to determine the potential increase in livestock production that would result from adoption of a new technology, and how an economic surplus model can be used to value the estimated productivity impacts. The particular problem examined is trypanosomosis in cattle in Africa, and the potential research product is a multi-component vaccine. The results suggest that the potential benefits of trypanosomiasis control, in terms of meat and milk productivity alone are worth over US$ 700 million per year in Africa. The methodology developed in this study can be used to measure the benefits of alleviating constraints to livestock production and the potential returns to research and development approaches addressing those constraints. The results of this study will assist in research priority setting and have highlighted the need for further research aimed at better understanding who the beneficiaries of the vaccine will be, and how it will reach them

Injury Risk Estimation Expertise Assessing the ACL Injury Risk Estimation Quiz

Background: Available methods for screening anterior cruciate ligament (ACL) injury risk are effective but limited in application as they generally rely on expensive and time-consuming biomechanical movement analysis. A potential efficient alternative to biomechanical screening is skilled movement analysis via visual inspection (ie, having experts estimate injury risk factors based on observations of athletes’ movements). Purpose: To develop a brief, valid psychometric assessment of ACL injury risk factor estimation skill: the ACL Injury Risk Estimation Quiz (ACL-IQ). Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: A total of 660 individuals participated in various stages of the study, including athletes, physicians, physical therapists, athletic trainers, exercise science researchers/students, and members of the general public in the United States. The ACL-IQ was fully computerized and made available online (www.ACL-IQ.org). Item sampling/reduction, reliability analysis, cross-validation, and convergent/discriminant validity analysis were conducted to optimize the efficiency and validity of the assessment. Results: Psychometric optimization techniques identified a short (mean time, 2 min 24 s), robust, 5-item assessment with high reliability (test-retest: r = 0.90) and consistent discriminability (average difference of exercise science professionals vs general population: Cohen d = 1.98). Exercise science professionals and general population individuals scored 74% and 53% correct, respectively. Convergent and discriminant validity was demonstrated. Scores on the ACL-IQ were most associated with ACL knowledge and various cue utilities and were least associated with domain-general spatial/decision-making ability, personality, or other demographic variables. Overall, 23% of the total sample (40% exercise science professionals; 6% general population) performed better than or equal to the ACL nomogram. Conclusion: This study presents the results of a systematic approach to assess individual differences in ACL injury risk factor estimation skill; the assessment approach is efficient (ie, it can be completed in\3 min) and psychometrically robust. The results provide evidence that some individuals have the ability to visually estimate ACL injury risk factors more accurately than other instrument-based ACL risk estimation methods (ie, ACL nomogram). The ACL-IQ provides the foundation for assessing the efficacy of observational ACL injury risk factor assessment (ie, does simple skilled visual inspection reduce ACL injuries?). It also provides a representative task environment that can be used to increase our understanding of the perceptual-cognitive mechanisms underlying observational movement analysis and to improve injury risk assessment performance

Modeling and Simulation of Ion-Induced Volume Phase Transitions in Chemically-Active Polyelectrolyte Gels

Ion-induced volume phase transitions in polyelectrolyte gels play an important role in physiological processes such as mucus storage and secretion in the gut, nerve tissue excitation, and DNA packaging. Biological experiments show that polyelectrolyte gels may swell or collapse rapidly due to changes in external conditions such as ionic composition. The volume phase transition is accompanied by a monovalent/ divalent ion exchange between the polymer network and the solvent that make up the gel. We propose a 2D computational method for simulating mucus swelling and deswelling with a two-fluid mixture model. The model includes electro-diffusive transport of ionic species, the coupled motion of the polymer network and hydrating fluid, and chemical interactions between the network and dissolved ions. Each ionic species in the solvent phase is subject to a Nernst–Planck type equation. Together with the electro-neutrality constraint, these equations constitute a system of non-linear parabolic partial differ ential equations subject to an algebraic constraint. The discretized system is solved by a novel Schur complement reduction scheme. Numerical results indicate that the method is very efficient, robust and accurate, even for problems which exhibit large spatial gradients in the concentration of ions. The computational effectiveness of the new methods is demonstrated through accuracy and efficiency metrics and through investigation of some of the factors that influence ion-induced volume phase transitions. The chemical forces acting on the gel are responsible for the unique volume phase transitions that occur within the gel. They include entropic, short-range, and electric forces, which explicitly depend on the bath environment as well as the chemical and structural properties of the gel. A major discovery from our experimental investigations is that depending on the charge distribution on the network, as well as the advective and diffusive transport of the ionic species, the induced electric field may either promote or oppose the swelling of a polyelectrolyte gel. Another significant discovery is that different components of the short range interaction force can drive swelling or deswelling of the gel. Depending on the properties of the gel, different components of the short-range force can have a competing effect on the swelling or deswelling behavior, yielding unique pattern formation within the polyelectrolyte gel. Finally, this work introduces and develops a novel computational framework for simulating multiphase mixture models on an adaptively refined mesh. The adaptive mesh refinement (AMR) technique is necessary for simulating complicated fluid models in order to gain speed enhancements and improved accuracy for features that require high resolution. Our preliminary results demonstrate the capabilities of the AMR fluid solver in adaptively refining regions of interest, thereby reducing the computational cost when simulating the coupled motion of the polymer network and solvent

Intergroup dialogue: A critical-dialogic approach to learning about difference, inequality, and social justice

The authors describe and evaluate an approach to engaging students in exploring social identities, understanding inequality, and identifying avenues for individual and collective action for greater social justice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57350/1/284_ftp.pd

Prospectus, October 31, 2001

https://spark.parkland.edu/prospectus_2001/1029/thumbnail.jp

Prospectus, September 26, 2001

https://spark.parkland.edu/prospectus_2001/1024/thumbnail.jp