Browsing by Author "Liu, S"

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Open Access
Area under the Curve: Analysis of Approach-Related Recovery Time in 165 Operative Cervical Spondylotic Myelopathy Patients with a 2-Year Follow-Up
(Global Spine Journal, 2015-05-01) Challier, V; Smith, J; Shaffrey, C; Kim, HJ; Arnold, P; Liu, S; Scheer, J; Chapman, J; Protopsaltis, T; Lafage, V; Schwab, F; Massicotte, E; Yoon, ST; Fehlings, M; Ames, C
Introduction Much debate about postoperative outcomes regarding surgical approaches for cervical spondylotic myelopathy (CSM) exists in the literature with no clear evidence of superiority. We propose a novel method for assessing health-related quality of life (HRQOL) outcomes by taking into account each patient's baseline at postoperative time points and analyzing the “area under the curve” (AUC), a proxy for suffering time. Patients and Methods Post hoc analysis of a prospective, multicenter database of patients with CSM. A total of 165 patients met the following inclusion criteria: symptomatic CSM, age older than 18 years, and 2-year follow-up with modified Japanese Orthopaedic Association (mJOA) and neck disability index (NDI). The anterior approach group (AAG) ( n = 110) and posterior approach group (PAG) ( n = 55) were compared at baseline, 1 year, and 2 years for each HRQOL. This comparison was repeated with normalization, using the patient's baseline as the anchor, followed by an integration and comparison of AUC. Results and Conclusion: For the first time, AUC analysis was applied to evaluating patients with CSM. Nonnormalized HRQOLs demonstrated the AAG started higher and met better standards at all times points compared with the PAG. Normalized mJOA demonstrated the PAG actually did better at 2 years, whereas NDI suggested that the AAG did better, although this was not significant. AUC analysis further supported the superiority of the PAG, with statistical significance at 1 and 2 years' time points, suggesting that patients who undergo the posterior approach may suffer less in the first 2 years of their postoperative course.
Open Access
Coercive Legacies: From Rebel Governance to Authoritarian Control
(The Journal of Politics, 2023-09-16) Liu, S
Open Access
Dynamic vision training transfers positively to batting practice performance among collegiate baseball batters
(Psychology of Sport and Exercise, 2020-11-01) Liu, S; Ferris, LM; Hilbig, S; Asamoa, E; LaRue, JL; Lyon, D; Connolly, K; Port, N; Appelbaum, LG
© 2020 Elsevier Ltd A growing body of evidence demonstrates visual, perceptual, and oculomotor abilities contribute to batting performance in baseball and there is interest in whether training such abilities can transfer positively to batting performance. The current study tested this question through a pre-registered, randomized, and placebo-controlled intervention, conducted with 24 collegiate baseball players at two NCAA Division 1 universities. Athletes were randomized to receive either dynamic vision training consisting of stroboscopic, anticipatory timing, and eye quickness drills, or placebo drills stylized after control procedures in previous vision therapy studies. Generalized near-transfer was tested via a digital visual-motor task battery (n = 20), while sports-specific intermediate and far transfer of training were evaluated through instrumented batting practice metrics (n = 14) and box score performance in NCAA-sanctioned games (n = 12), respectively. The effects of training group were tested on these outcome measures while controlling for covariates such as pre-training expectations and site. Participants averaged 8.50 hours of training with no significant group differences in training adherence, expectations, or baseline assessments. ANCOVA revealed no group differences in measures of visual-motor skills or NCAA game statistics. However, batting practice demonstrated significant improvements in launch angle (p = 0.002, Cohen's d = 0.74) and hit distance (p < 0.001, Cohen's d = 0.70) for the active training cohort relative to the placebo control. This controlled and pre-registered pilot study therefore provides preliminary evidence that vision training may improve batting practice performance, creating new opportunities for the transfer of skill training and warranting further study.
Open Access
Executive summary: heart disease and stroke statistics-2015 update: a report from the american heart association.
(Circulation, 2015-01) Mozaffarian, D; Benjamin, EJ; Go, AS; Arnett, DK; Blaha, MJ; Cushman, M; de Ferranti, S; Després, JP; Fullerton, HJ; Howard, VJ; Huffman, MD; Judd, SE; Kissela, BM; Lackland, DT; Lichtman, JH; Lisabeth, LD; Liu, S; Mackey, RH; Matchar, DB; McGuire, DK; Mohler, ER; Moy, CS; Muntner, P; Mussolino, ME; Nasir, K; Neumar, RW; Nichol, G; Palaniappan, L; Pandey, DK; Reeves, MJ; Rodriguez, CJ; Sorlie, PD; Stein, J; Towfighi, A; Turan, TN; Virani, SS; Willey, JZ; Woo, D; Yeh, RW; Turner, MB
Each year, the American Heart Association (AHA), in conjunction with the Centers for Disease Control and Prevention, the National Institutes of Health, and other government agencies, brings together the most up-to-date statistics related to heart disease, stroke, and other cardiovascular and metabolic diseases and presents them in its Heart Disease and Stroke Statistical Update. The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, and others seeking the best available data on these conditions. Together, cardiovascular disease (CVD) and stroke produce immense health and economic burdens in the United States and globally. The Statistical Update brings together in a single document up-to-date information on the core health behaviors and health factors that define cardiovascular health; a range of major clinical disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, and peripheral arterial disease); and the associated outcomes (including quality of care, procedures, and economic costs). Since 2009, the annual versions of the Statistical Update have been cited >20 000 times in the literature. In 2014 alone, the various Statistical Updates were cited >5700 times. Each annual version of the Statistical Update undergoes major revisions to include the newest nationally representative data, add additional relevant published scientific findings, remove older information, add new sections or chapters, and increase the number of ways to access and use the assembled information. This year-long process, which begins as soon as the previous Statistical Update is published, is performed by the AHA Statistics Committee faculty volunteers and staff. For example, this year's edition includes a new chapter on cardiac arrest, new data on the monitoring and benefits of cardiovascular health in the population, additional information in many chapters on the global CVD and stroke burden, and further new focus on evidence-based approaches to changing behaviors, implementation strategies, and implications of the AHA's 2020 Impact Goals. Below are a few highlights from this year's Update.
Open Access
How Weakly Institutionalized Parties Monitor Brokers in Developing Democracies: Evidence from Postconflict Liberia
(American Journal of Political Science, 2020-10) Bowles, J; Larreguy, H; Liu, S
Open Access
Service Cynicism: How Civic Disengagement Develops
(Politics & Society, 2018-03) Cheng, T; Liu, S
How does civic disengagement develop? This article examines the theory that the dissatisfaction and disengagement citizens develop toward one government agency can extend to an alternative agency. Leveraging police precinct-level data on 311 calls and criminal complaints from 2004 to 2012 in New York City, it investigates whether government responsiveness to municipal issues predicts citizens’ willingness to submit criminal complaints to the police. The study finds that predictors of disengagement with law enforcement extend beyond negative interactions with law enforcement alone. Rather, the time it takes local government officials to fix a 311 request for services, such as filling potholes and abating noise, shapes the likelihood that residents will file misdemeanor criminal complaints. Thus policymakers must account for the policy environment beyond their agency’s domain to alleviate citizens’ dissatisfaction and disengagement with government overall.
Open Access
SNIa-Cosmology Analysis Results from Simulated LSST Images: from Difference Imaging to Constraints on Dark Energy
Sánchez, B; Kessler, R; Scolnic, D; Armstrong, B; Biswas, R; Bogart, J; Chiang, J; Cohen-Tanugi, J; Fouchez, D; Gris, Ph; Heitmann, K; Hložek, R; Jha, S; Kelly, H; Liu, S; Narayan, G; Racine, B; Rykoff, E; Sullivan, M; Walter, C; Wood-Vasey, M; Collaboration, The LSST Dark Energy Science
The Vera Rubin Observatory Legacy Survey of Space and Time (LSST) is expected to process ${\sim}10^6$ transient detections per night. For precision measurements of cosmological parameters and rates, it is critical to understand the detection efficiency, magnitude limits, artifact contamination levels, and biases in the selection and photometry. Here we rigorously test the LSST Difference Image Analysis (DIA) pipeline using simulated images from the Rubin Observatory LSST Dark Energy Science Collaboration (DESC) Data Challenge (DC2) simulation for the Wide-Fast-Deep (WFD) survey area. DC2 is the first large-scale (300 deg$^2$) image simulation of a transient survey that includes realistic cadence, variable observing conditions, and CCD image artifacts. We analyze ${\sim}$15 deg$^2$ of DC2 over a 5-year time-span in which artificial point-sources from Type Ia Supernovae (SNIa) light curves have been overlaid onto the images. We measure the detection efficiency as a function of Signal-to-Noise Ratio (SNR) and find a $50\%$ efficiency at $\rm{SNR}=5.8$. The magnitude limits for each filter are: $u=23.66$, $g=24.69$, $r=24.06$, $i=23.45$, $z=22.54$, $y=21.62$ $\rm{mag}$. The artifact contamination is $\sim90\%$ of detections, corresponding to $\sim1000$ artifacts/deg$^2$ in $g$ band, and falling to 300 per deg$^2$ in $y$ band. The photometry has biases $<1\%$ for magnitudes $19.5 < m <23$. Our DIA performance on simulated images is similar to that of the Dark Energy Survey pipeline applied to real images. We also characterize DC2 image properties to produce catalog-level simulations needed for distance bias corrections. We find good agreement between DC2 data and simulations for distributions of SNR, redshift, and fitted light-curve properties. Applying a realistic SNIa-cosmology analysis for redshifts $z<1$, we recover the input cosmology parameters to within statistical uncertainties.
Open Access
Visual and oculomotor abilities predict professional baseball batting performance
(International Journal of Performance Analysis in Sport, 2020-07-03) Liu, S; Edmunds, FR; Burris, K; Appelbaum, LG
© 2020, © 2020 Cardiff Metropolitan University. Scientists and practitioners have long debated about the specific visual skills needed to excel at hitting a pitched baseball. To advance this debate, we evaluated the relationship between pre-season visual and oculomotor evaluations and pitch-by-pitch season performance data from professional baseball batters. Eye tracking, visual-motor, and optometric evaluations collected during spring training 2018 were obtained from 71 professional baseball players. Pitch-level data from Trackman 3D Doppler radar were obtained from these players during the subsequent season and used to generate batting propensity scores for swinging at pitches out of the strike zone (O-Swing), swinging at pitches in the strike zone (Z-Swing), and swinging at, but missing pitches in the strike zone (Z-Miss). Nested regression models to tested which evaluation(s) best predicted standardised plate discipline scores as well as batters’ highest attained league levels during the season. Results indicated that visual evaluations relying on eye tracking (smooth pursuit accuracy and oculomotor processing speed) significantly predicted the highest attained league level andpropensity scores associated with O-Swing and Z-Swing, but not Z-Miss. These exploratory findings indicate that batters with superior visual and oculomotor abilities are more discerning at the plate. These results provide new information about the role of vision in baseball batting.