• Reviewing COVID-19 Modelling amidst Recent United States Protests

      Fasehun, Luther-King; 0000-0002-8798-5433 (2020-07-06)
    • Sampling bias and incorrect rooting make phylogenetic network tracing of SARS-COV-2 infections unreliable

      Mavian, Carla; Pond, Sergei; Marini, Simone; Magalis, Brittany Rife; Vandamme, Anne-Mieke; Dellicour, Simon; Scarpino, Samuel V.; Houldcroft, Charlotte; Villabona-Arenas, Julian; Paisie, Taylor K.; Trovão, Nídia S.; Boucher, Christina; Zhang, Yun; Scheuermann, Richard H.; Gascuel, Olivier; Lam, Tommy Tsan-Yuk; Suchard, Marc A.; Abecasis, Ana; Wilkinson, Eduan; de Oliveira, Tulio; Bento, Ana I.; Schmidt, Heiko A.; Martin, Darren; Hadfield, James; Faria, Nuno; Grubaugh, Nathan D.; Neher, Richard A.; Baele, Guy; Lemey, Philippe; Stadler, Tanja; Albert, Jan; Crandall, Keith A.; Leitner, Thomas; Stamatakis, Alexandros; Prosperi, Mattia; Salemi, Marco; 0000-0003-4817-4029 (2020-05-07)
    • Sensorimotor Oscillations During a Reciprocal Touch Paradigm With a Human or Robot Partner

      Tirassa, Maurizio (2018-12-10)
      Robots provide an opportunity to extend research on the cognitive, perceptual, and neural processes involved in social interaction. This study examined how sensorimotor oscillatory electroencephalogram (EEG) activity can be influenced by the perceived nature of a task partner – human or robot – during a novel “reciprocal touch” paradigm. Twenty adult participants viewed a demonstration of a robot that could “feel” tactile stimulation through a haptic sensor on its hand and “see” changes in light through a photoreceptor at the level of the eyes; the robot responded to touch or changes in light by moving a contralateral digit. During EEG collection, participants engaged in a joint task that involved sending tactile stimulation to a partner (robot or human) and receiving tactile stimulation back. Tactile stimulation sent by the participant was initiated by a button press and was delivered 1500 ms later via an inflatable membrane on the hand of the human or on the haptic sensor of the robot partner. Stimulation to the participant’s finger (from the partner) was sent on a fixed schedule, regardless of partner type. We analyzed activity of the sensorimotor mu rhythm during anticipation of tactile stimulation to the right hand, comparing mu activity at central electrode sites when participants believed that tactile stimulation was initiated by a robot or a human, and to trials in which “nobody” received stimulation. There was a significant difference in contralateral mu rhythm activity between anticipating stimulation from a human partner and the “nobody” condition. This effect was less pronounced for anticipation of stimulation from the robot partner. Analyses also examined beta rhythm responses to the execution of the button press, comparing oscillatory activity when participants sent tactile stimulation to the robot or the human partner. The extent of beta rebound at frontocentral electrode sites following the button press differed between conditions, with a significantly larger increase in beta power when participants sent tactile stimulation to a robot partner compared to the human partner. This increase in beta power may reflect greater predictably in event outcomes. This new paradigm and the novel findings advance the neuroscientific study of human–robot interaction.
    • The Effects of Selective Muscle Weakness on Muscle Coordination in the Human Arm

      Zaffagnini, Stefano (2018-09-19)
      Despite the fundamental importance of muscle coordination in daily life, it is currently unclear how muscle coordination adapts when the musculoskeletal system is perturbed. In this study, we quantified the impact of selective muscle weakness on several metrics of muscle coordination. Seven healthy subjects performed 2D and 3D isometric force target matches, while electromyographic (EMG) signals were recorded from 13 elbow and shoulder muscles. Subsequently, muscle weakness was induced by a motor point block of brachialis muscle. Postblock subjects repeated the force generation tasks. We quantified muscle coordination pre- and postblock using three metrics: tuning curve preferred direction, tuning curve area, and motor modules analysis via nonnegative matrix factorization. For most muscles, the tuning direction for the 2D protocol was not substantially altered postblock, while tuning areas changed more drastically. Typically, five motor modules were identified from the 3D task, and four motor modules were identified in the 2D task; this result held across both pre- and postblock conditions. The composition of one or two motor modules, ones that involved mainly the activation of shoulder muscles, was altered postblock. Our results demonstrate that selective muscle weakness can induce nonintuitive alternations in muscle coordination in the mechanically redundant human arm.
    • The roles of Lewis acidic additives in organotransition metal catalysis

      Becica, Joseph; Dobereiner, Graham; 0000-0001-6885-2021 (2019-01-22)
      We describe recent examples of prominent reactions in organic synthesis that involve transition metal and Lewis acid cocatalysts. Introducing Lewis acid additives to transition metal catalysis can enable new reactivity or improve activity and selectivity of an existing process. Several studies are highlighted to illustrate the possible roles of Lewis acids in catalytic mechanisms. The uses of Lewis acid additives in bond-breaking catalysis (C–C activation, C–H activation, and hydrogenolysis reactions) and bond-forming catalysis (Au-catalysed alkyne functionalisation, Pd-catalysed C–C and C–N bond formation) are reviewed.
    • Tonic Neuromuscular Processing Affects Postural Adaptation Differently in Aging and Parkinson's Disease

      Fung, Joyce (2019-01-21)
      The combination of phasic and tonic neuromuscular processes are involved in the maintenance of normal upright posture. The latter is of particular importance in some pathologies, such as Parkinson's Disease (PD), which is known by one of its cardinal symptoms—tonic dysfunction (i.e., rigidity). Changes in tonic function may also occur during healthy aging. In this investigation, somatosensory input was manipulated by changing the support surface orientation for prolonged periods of quiet stance (QS). The aim was to shed light on how long-term tonic responses called postural lean after-effects are affected by aging and age-related neuropathology. Forty one participants were tested: 19 healthy young (25±5 years), 13 healthy older (63±8 years), and 9 adults with PD (63±5 years). Baseline conditions were eyes-closed QS on a stable surface or standing on an unstable, sway-referenced (SR) surface. Four experimental conditions combined two types of toes-up ramp tilt adaptation (120 s of toes-up static 7° tilt or sinusoidal 7° ± 3° tilt) with two types of post-adaptation (120 s of QS or SR). Results revealed postural after-effects during post-adaptation QS showing significant anterior COP shift for both young and older adults (p < 0.0001), but not PD (p > 0.06, n.s.). Compared to young, postural after-effects in older adults showed longer decay constants and did not return to baseline COP within the 120 s post-adaptation period (p < 0.05). Postural after-effects during SR, which appeared as toes-up surface tilt were highly significant in healthy populations (p = 0.001), but took longer to develop in PD. Younger adults showed significantly larger dorsiflexion (p < 0.01) and faster decay constants than older adults (p < 0.05). In summary, (1) postural after-effects decayed to baseline when post-tilt surface was stable but were retained and even grew larger post-adaptation in the SR surface conditions in all groups, (2) postural after-effects differed between healthy age groups, (3) PD showed less adaptation to surface changes. Differences in size and decay of after-effects between healthy and PD groups suggest tonic neuromuscular processes play a role in how adaptable postural control is to changing surface conditions and this is affected by healthy aging and basal ganglia function.
    • Understanding Holistic Graduate Admissions Practices: Summary of a Current Research Study

      Paris, Joseph; 0000-0001-7636-903X (2021)
      Holistic review, or the consideration of a wide range of applicant qualities including “non-cognitive” or personal attributes, is a growing strategy for expanding the predictive potential derived from the variables most commonly evaluated in graduate admissions: cumulative undergraduate GPA and standardized test scores such as the GRE (Kent & McCarthy, 2016; Okahana et al., 2018). This article describes a NAGAP-sponsored research study that responds to the need identified by Kent and McCarthy (2016) for a “clearer understanding of what constitutes a truly ‘holistic’ graduate admissions process for master’s and doctoral programs” (p. iv). The project also aims to generate guidelines for the practice of holistic review in graduate admissions.
    • What do social groups have to do with culture? The crucial role of shared experience

      Bergey, Bradley W.; Kaplan, Avi; 0000-0002-0495-7219; 0000-0002-2898-0085 (2010)