Criterion validity of the Pittsburgh Sleep Quality Index: Investigation in a non-clinical sample

The objective of this study was to investigate the reliability and validity of the Pittsburgh Sleep Quality Index (PSQI) in a non-clinical sample consisting of younger and older adults. There has been little research validating the PSQI with respect to multinight recording as with actigraphy, and more validation is needed in samples not specifically selected for clinical disturbance. Also, the degree to which the PSQI scores may reflect depressive symptoms versus actual sleep disturbance remains unclear. One-hundred and twelve volunteers (53 younger and 59 older) were screened for their ability to perform treadmill exercises; inclusion was not based on sleep disturbance or depression. Internal homogeneity was evaluated by correlating PSQI component scores with the global score. Global and component scores were correlated with a sleep diary, actigraphy, and centers for epidemiological studies – depression scale scores to investigate criterion validity. Results showed high internal homogeneity. PSQI global score correlated appreciably with sleep diary variables and the depression scale, but not with any actigraphic sleep variables. These results suggest that the PSQI has good internal homogeneity, but may be less reflective of actual sleep parameters than a negative cognitive viewpoint or pessimistic thinking. The sleep complaints measured may often be more indicative of general dissatisfaction than of any specifically sleep-related disturbance

PASSIVE SUPPRESSION OF AEROELASTIC INSTABILITIES OF IN-FLOW WINGS BY TARGETED ENERGY TRANSFERS TO LIGHTWEIGHT ESSENTIALLY NONLINEAR ATTACHMENTS

Theoretical and experimental suppression of aeroelastic instabilities by means of broadband passive targeted energy transfers has been recently studied. A single-degree-offreedom (SDOF) nonlinear energy sink (NES) was coupled to a 2-DOF rigid wing modeled in the low-speed, subsonic regime with quasi-steady aerodynamic theory. The nonlinear attachment was designed and optimized to suppress the critical nonlinear modal energy exchanges between the flow and the (pitch and heave) wing modes, thus suppressing the (transient) triggering mechanism of aeroelastic instability. We performed bifurcation analysis to find regions of robust passive aeroelastic suppression in parameter space. Then, we employed multi-degreeof-freedom nonlinear energy sinks (MDOF NESs) to improve robustness of the aeroelastic instability suppression. Bifurcation analysis by a numerical continuation technique demonstrated that controlling the occurrence of a limit point cycle (LPC or saddle-node) bifurcation point above a Hopf bifurcation point is crucial to enhancing suppression robustness. MDOF NESs not only can enhance robustness of suppression against even strong gust-like disturbances, but they require lower NES mass compared to SDOF NES designs. The validity of the theoretical findings was proven by a series of wind tunnel experiments

Let’s Play! Gamifying Engineering Ethics Education Through the Development of Competitive and Collaborative Activities

Engineering ethics is an extremely important topic that needs to be focused on more in engineering curricula, as many of the projects that engineers work on have a profound impact on society. There are many pitfalls with the traditional ways in which ethics is taught to engineering students as an abstract philosophical topic, rather than personal decision making situated in complex real contexts. The three main approaches that are used for engineering ethics include being taught by a professor outside of the engineering space, being taught late in their curriculum such as during a senior capstone project, and being taught in a short period of time as a module of another class. The downsides to these approaches are that students do not see ethics as equally important as some other topics, they do not see it consistently integrated throughout the curriculum, nor do they see ethical decisions as complex nuanced, and situated in context,. Game-based learning is a means to actively engage students in interrogating the complexities of ethical decision making. Game play can align with student learning objectives as well as improve student knowledge, behaviors, and dispositions. Our paper introduces three games that are designed to assist in the development of students’ ethical awareness and reasoning. Three engineering ethics games have been developed as the foundation for an NSF-funded project that investigates the empirical impacts of game play on ethical reasoning and decision making. Cards Against Engineering Ethics, Toxic Workplaces, and Mars: An Ethical Expedition have all been in development for the last few years. Each game targets specific ethics learning outcomes as well as different play mechanics. These outcomes include identifying the complexities of ethical dilemmas, evaluating responses to ethical situations in context, and promoting ethical discussions among peers. The time required to play each game varies, ranging from 20 minutes, to 75 minutes, to 5 minutes once a week for 15 weeks. The benefits that these games include an enriched learning experience, student engagement, and a greater connection between ethics and real life

Empirical Mode Decomposition in the Reduced-Order Modeling of Aeroelastic Systems

peer reviewedA relationship between IntrinsicMode Functions (IMFs), derived from the Empirical Mode Decomposition (EMD), and the slow-flow model of a nonlinear dynamical system has been exploited in the development of the Slow Flow Model Identification (SFMI) method for strongly nonlinear systems, in which the physical parameters of such systems are identified from experimental data. Both the slow flows and IMFs provide the means to expand a general multicomponent signal in terms of a series of simpler, dominant, monocomponent signals. The slow flows are obtained analytically, for example through application of the method of complexification and averaging (CxA), which transforms the equations of motion into a set of approximate equations in amplitude and phase for each modeled frequency component. In contrast, the EMD characterizes a signal through the envelope and phase of its elemental components, the IMFs. Thus, between nonlinear transitions, the equations derived using the CxA method govern the amplitude and phase of the modeled IMFs. Application of SFMI has, until now, been limited to low-dimensional systems subjected to impulsive excitation. Herein, the method is extended to identification of a planar rigid airfoi

How does iron interact with sporopollenin exine capsules? An X-ray absorption study including microfocus XANES and XRF imaging

Sporopollenin exine capsules (SECs) derived from plant spores and pollen grains have been proposed as adsorption, remediation and drug delivery agents. Despite many studies there is scant structural data available. This X-ray absorption investigation represents the first direct structural data on the interaction of metals with SECs and allows elucidation of their structure–property relationships. Fe K-edge XANES and EXAFS data have shown that the iron local environment in SECs (derived from Lycopodium clavatum) reacted with aqueous ferric chloride solutions is similar to that of ferrihydrite (FeOOH) and by implication ferritin. Fe Kα XRF micro-focus experiments show that there is a poor correlation between the iron distribution and the underlying SEC structure indicating that the SEC is coated in the FeOOH material. In contrast, the Fe Kα XRF micro-focus experiments on SECs reacted with aqueous ferrous chloride solutions show that there is a very high correlation between the iron distribution and the SEC structure, indicating a much more specific form of interaction of the iron with the SEC surface functional groups. Fe K-edge XANES and EXAFS data show that the FeII can be easily oxidised to give a structure similar to, but not identical to that in the FeIII case, and that even if anaerobic conditions are used there is still partial oxidation to FeIII

Engineering Ethics Through High-Impact Collaborative/Competitive Scenarios (E-ETHICCS)

Engineering grand challenges increasingly involve numerous social and ethical considerations that transcend the technical skills that dominate traditional engineering education. Engineering solutions often have major, long-lasting impacts on society. Since the process of technical innovation occurs in increasingly complex social exchanges, engineers are frequently confronted with social and ethical dilemmas in their professional lives. How do students acquire the skills needed to tackle these problems? The authors hypothesize that placing engineering challenges and solutions in a classroom context while emphasizing social engagement and impact facilitates the development of engineering students as moral agents who understand the consequences of their decisions. Thus, a collaboration of investigators from the grantee universities are investigating how game-based educational interventions with strongly situated components influence early-curriculum engineering students\u27 ethical awareness and decision making. This paper offers an overview of the progress to date of this three year, NSF Improving Undergraduate STEM Education (IUSE) grant that aims to (1) characterize the ethical awareness and decision making of first-year engineering students, (2) develop game-based learning interventions focused on ethical decision making, and (3) determine how (and why) game-based approaches affect students’ ethical awareness in engineering and the advantages of such approaches over non game-based approaches. Results from this investigation will offer the engineering education community insight into how engineering students approach problem solving through the lens of ethical reasoning and decision making, potentially transforming an often overlooked part of engineering curricula for decades to come

IMPACT OF PASSIVE LEG MOVEMENT ON LOWER LIMB VASCULAR FUNCTION IN PATIENTS WITH A SPINAL CORD INJURY

Background: Individuals with spinal cord injuries (SCI) are at a greater risk for developing cardiovascular diseases. Of note, post injury mediated increases in physical inactivity leads to muscle atrophy, which also results in vascular dysfunction in this population. Although a growing body of evidence suggests that passive leg movement (PLM) may be a useful exercise modality to improve peripheral blood flow and skeletal muscle activation in individuals with limited mobility, few studies have examined the impact of PLM on local skeletal muscle blood flow. Therefore, there is a need to examine the impact of PLM on lower limb vascular function and skeletal muscle oxygen utilization capacity in patients with SCI. Methods: Individuals with SCI (n=2) and healthy age-matched controls (CON, n=5) were recruited for this study. Participants were fitted with a standard knee brace and were instructed to rest in the seated position for 20 minutes with their legs bent at 90. PLM was performed by flexion and extension of the lower leg (90-180) at a rate of 1 Hz (60 bpm) for 5 minutes. A Doppler ultrasound was located on the superficial femoral artery, and blood flow and diameter were measured for 5 minutes at rest and during the PLM protocol. Following the PLM protocol, the leg was held in the extended position (180) for 5 minutes of recovery. Results: We found that the SCI group had a significantly lower blood flow response to PLM compared to the CON group (p=0.004). Furthermore, post-PLM femoral artery blood velocity and shear rate significantly increased in both SCI and CON compared to pre-PLM (p=0.014, and p=0.016, respectively) but no differences were found between groups. Finally, the SCI group had significantly smaller vessel diameters compared with CON (pConclusion: We found that PLM could efficiently increase blood flow and blood velocity in SCI. Although the magnitude of this increase was significantly lower in SCI compared to healthy age-matched control, PLM produced shear rates in the leg arteries that were similar between SCI and CON, which indicates that PLM may potentially be an efficient exercise modality to improve leg vascular function in individuals with SCI