Norman Julius Zabusky OBITUARY

Norman Julius Zabusky, who laid the foundations for several critical advancements in nonlinear science and experimental mathematics, died of idiopathic pulmonary fibrosis on 5 February 2018 in Beersheba, Israel. He also made fundamental contributions to computational fluid dynamics and advocated the importance of visualization in science.Published versio

Dispersed Trading and the Prevention of Market Failure: The Case of the Copenhagen Stock Exchange

With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight into this issue by examining trading behavior at the Copenhagen Stock Exchange during a major blackout. We find that although market quality declined, markets remained functional and some price discovery occurred during the blackout period suggesting that the NOREX structure of interlinked trading systems combined with widely dispersed trading locations may be a viable means of protection against market failure during massive power disruptions or terrorist attacks.Power failure; Fragmented markets; Market failure;

Defining the complementarities between antibodies and haptens to refine our understanding and aid the prediction of a successful binding interaction

Acknowledgments The authors would like to thank the Scottish Universities Life Sciences Alliance (SULSA) for their support.Peer reviewedPublisher PD

Patterns of postural deformity in non-ambulant people with cerebral palsy: what is the relationship between the direction of scoliosis, direction of pelvic obliquity, direction of windswept hip deformity and side of hip dislocation?

Objective: To investigate: (a) associations between the direction of scoliosis, direction of pelvic obliquity, direction of windswept deformity and side of hip subluxation/dislocation in non-ambulant people with cerebral palsy; and (b) the lateral distribution of these postural asymmetries

A Prospective Randomized Comparison of Patient Specific Instruments with Standard TKA Instrumentation

Introduction: Patient specific instruments (PSI), an alternative to standard total knee arthroplasty (TKA) technology, have shown mixed results regarding effectiveness in previous studies. This study evaluated the accuracy of the predicted PSI plan, compared incremental cost savings with PSI, and compared outcomes of PSI and standard TKA patients. Patients and Methods: This randomized, prospective feasibility study included 19 primary TKA patients receiving a cruciate-retaining cemented prosthesis from a single surgeon (DCA). 9 patients randomized to PSI received a pre-operative knee MRI for PSI fabrication using proprietary software.10 standard TKAs were completed. Operative data collected included operating times, implant details, femoral (medial/lateral distal and posterior) and tibial (medial/lateral) resections, and instrument trays used. Hospitalization data collected included length of stay, blood loss, drain output, and transfusions. SF-36 and WOMAC scores, routine radiographic analysis, and femoral-tibial angles were collected pre- and post-operatively. Costs of operating room use and anesthesia, implants, and hospitalization were collected. Statistical analyses included t-tests and chi-square tests. Results: All implant sizes matched surgical team adjusted PSI software plans. Flexion gap resection (posterior medial/lateral femur) was extremely accurate (averagemm). Sagittal plane tibial component posterior slope was larger in PSI TKA (mean 7.3 degrees) than standard instrumentation (mean 4.2 degrees) (p0.05). There were no differences in operating room times or hospitalization data, and there were no significant differences in functional outcomes between the two groups (p\u3e0.05). PSI patients used 4 fewer instrument trays per case (p\u3c0.0001). Conclusion: PSI TKA demonstrated outstanding accuracy in bone resection when compared with the pre-operative plan, and resulted in appropriate limb and component alignment with primary TKA. The number of instrument trays used in PSI TKA was significantly less than standard TKA, which led to less cost for instrument sterilization and assembly

Ariel - Volume 2 Number 7

Editors Richard J. Bonanno Robin A. Edwards Associate Editors Steven Ager Stephen Flynn Shep Dickman Tom Williams Lay-out Editor Eugenia Miller Contributing Editors Michael J. Blecker W. Cherry Light James J. Nocon Lynne Porter Editors Emeritus Delvyn C. Case, Jr. Paul M. Fernhof

Pre-operative Emotional Health Affects Post-operative Patient Function but not Patient Satisfaction Following Primary Total Hip Arthroplasty

Introduction: Total hip (THA) and knee (TKA) arthroplasty are highly successful treatments for end-stage arthritis. However, a subset of patients experience suboptimal post-operative gain in function. 1, 2 Previous studies have shown that pre-operative emotional health influences outcomes after TKA,3 but there is limited evidence on THA patients. We hypothesized that pre-operative emotional health does not affect patient satisfaction in THA patients. Methods: A secondary analysis of an existing registry at UMass of primary THA patients between 2008 and 2011 was conducted. Baseline demographic, clinical, emotional health (SF-36 MCS), and physical health (SF-36 PCS) data were collected electronically at the pre-operative visit. Post-operative SF-36 MCS, SF-36 PCS, and satisfaction scores were collected electronically between 6 months through 2 years follow-up. Bivariate analyses and multivariate logistic regression models were used. Results: The analysis included 316 primary THA patients with mean age 62±11 years, 55% female, mean BMI 30±5, mean PCS 31±8, and mean MCS 51±11. Patients with lower baseline emotional health scores reported significantly reduced mean post-operative physical function and emotional health (p45 (indicating excellent function, national norm = 50); whereas patients with baseline MCS≥50 had a mean 17±11 point increase in post-operative PCS with 71% of these patients reporting PCS\u3e45 (p\u3c0.001). Conclusion: In THA patients, post-operative emotional health and physical health are positively correlated with baseline emotional health, however post-operative patient satisfaction remains independent of baseline emotional health

Clustering Phase Transitions and Hysteresis: Pitfalls in Constructing Network Ensembles

Ensembles of networks are used as null models in many applications. However, simple null models often show much less clustering than their real-world counterparts. In this paper, we study a model where clustering is enhanced by means of a fugacity term as in the Strauss (or "triangle") model, but where the degree sequence is strictly preserved -- thus maintaining the quenched heterogeneity of nodes found in the original degree sequence. Similar models had been proposed previously in [R. Milo et al., Science 298, 824 (2002)]. We find that our model exhibits phase transitions as the fugacity is changed. For regular graphs (identical degrees for all nodes) with degree k > 2 we find a single first order transition. For all non-regular networks that we studied (including Erdos - Renyi and scale-free networks) we find multiple jumps resembling first order transitions, together with strong hysteresis. The latter transitions are driven by the sudden emergence of "cluster cores": groups of highly interconnected nodes with higher than average degrees. To study these cluster cores visually, we introduce q-clique adjacency plots. We find that these cluster cores constitute distinct communities which emerge spontaneously from the triangle generating process. Finally, we point out that cluster cores produce pitfalls when using the present (and similar) models as null models for strongly clustered networks, due to the very strong hysteresis which effectively leads to broken ergodicity on realistic time scales.Comment: 13 pages, 11 figure