Quantifying Spatiotemporal Chaos in Rayleigh-B\'enard Convection

Using large-scale parallel numerical simulations we explore spatiotemporal chaos in Rayleigh-B\'enard convection in a cylindrical domain with experimentally relevant boundary conditions. We use the variation of the spectrum of Lyapunov exponents and the leading order Lyapunov vector with system parameters to quantify states of high-dimensional chaos in fluid convection. We explore the relationship between the time dynamics of the spectrum of Lyapunov exponents and the pattern dynamics. For chaotic dynamics we find that all of the Lyapunov exponents are positively correlated with the leading order Lyapunov exponent and we quantify the details of their response to the dynamics of defects. The leading order Lyapunov vector is used to identify topological features of the fluid patterns that contribute significantly to the chaotic dynamics. Our results show a transition from boundary dominated dynamics to bulk dominated dynamics as the system size is increased. The spectrum of Lyapunov exponents is used to compute the variation of the fractal dimension with system parameters to quantify how the underlying high-dimensional strange attractor accommodates a range of different chaotic dynamics

Misdiagnosis, Mistreatment, and Harm - When Medical Care Ignores Social Forces.

The Case Studies in Social Medicine demonstrate that when physicians use only biologic or individual behavioral interventions to treat diseases that stem from or are exacerbated by social factors, we risk harming the patients we seek to serve

The effect of the Cox-maze procedure for atrial fibrillation concomitant to mitral and tricuspid valve surgery

ObjectivesAtrial fibrillation (AF) is associated with less favorable outcomes in patients undergoing mitral valve and tricuspid valve surgery. Despite growing evidence on the potential benefits of surgical ablation for AF there is significant variability among surgeons in treatment of AF. The purpose of our study was to assess the effect of the Cox-maze procedure on operative and follow-up outcomes.MethodsIn our prospective study, patients who underwent isolated mitral valve or mitral valve+tricuspid valve surgery without history of AF (n = 506), with untreated AF (n = 75), or with Cox-maze procedure (n = 236) were included (N = 817). Sinus rhythm was captured according to Heart Rhythm Society guidelines. Patients who underwent the Cox-maze procedure were propensity score matched to patients without history of AF resulting in 208 pairs of patients.ResultsOperative outcomes were comparable after propensity score matching (Cox-maze procedure vs no AF) stroke/transient ischemic attack (0.5% vs 0.5%; P = 1.00), renal failure (2.9% vs 1.4%; P = .34), and operative mortality (1.4% vs 1.4%; P = 1.00). High return to sinus rhythm was documented at 6, 12, and 24 months (92%, 91%, and 86%, respectively) as well as sinus rhythm off antiarrhythmic drugs (79%, 84%, and 82%, respectively). Incidence of embolic stroke in patients who underwent Cox-maze procedure was 1.7% (4 out of 232 patients) and 5.1 cases per 1000 person-years. No difference in 4-year cumulative survival between propensity score-matched groups (91.9% vs 86.9%; log rank, 1.67; P = .20), but higher for patients who underwent Cox-maze procedure versus patients with untreated AF (hazard ratio, 2.47; P = .048). Higher additive European System for Cardiac Operative Risk Evaluation (odds ratio, 1.40; P < .001) and limited surgeon experience with Cox-maze procedure (odds ratio, 3.60; P < .001) were significant predictors for failure to perform Cox-maze procedure.ConclusionsIn our center, 76% of patients undergoing mitral valve or mitral valve+tricuspid valve surgery experiencing AF underwent concomitant Cox-maze procedure, which is considerably higher than the national average. No increased morbidity was associated with the Cox-maze procedure with the benefit of very low thromboembolic rate. These results suggest the need for performance-based education for AF surgical ablation to achieve optimal outcomes

A Parental-Report Questionnaire for Language Abilities and Pragmatics in Children and Adolescents with Autism Spectrum Disorders

The aim of this study was to test and validate a parental-report questionnaire, which assesses language abilities and pragmatics, in children with Autism Spectrum Disorders (ASD). We report two experiments: The first served as the initial test and the second sought to provide the first assessment of convergent validity. In total, we recruited 230 parents, where approximately two-thirds had a child with ASD. Results of factor analyses showed a consistent factor structure within each subscale, and the internal consistency was excellent for both sub-scales (Cronbach’s alpha >0.90). Convergent validity was assessed by correlating the results of the questionnaire with two sub-scales of the Autism Quotient questionnaire. The correlations were all greater than 0.60. The final version of the questionnaire (following exclusion of problematic items) contains 30 items (12 for language abilities and 18 for pragmatics). We conclude that the questionnaire is a concise and practical instrument for use in a variety of contexts for assessing language functioning and communication in children with ASD

Salivary cortisol response to infant distress in pregnant women with depressive symptoms.

The Hypothalamic-Pituitary-Adrenal (HPA) axis has been proposed as a potential underlying biological mechanism linking prenatal depression with adverse offspring outcomes. However, it is unknown whether the reactivity of this system to stress is altered in pregnant women experiencing depression. The objective of this study was to investigate whether salivary cortisol response to a distressed infant film is enhanced in pregnant women with symptoms of depression compared with non-depressed controls. Salivary cortisol and subjective mood responses to the film were measured in 53 primiparous women, between 11 and 18 weeks gestation. Both groups showed similar increases in state anxiety in response to the film, but there was a significantly increased cortisol response in women experiencing symptoms of depression. Depression during pregnancy is associated with increased reactivity of the HPA axis. This is consistent with altered HPA axis functioning being a key mechanism by which prenatal mood disturbance can impact upon fetal development

Injection moulding: properties customization by varying process conditions

Injection moulding: properties customization by varying process condition

Complex injection moulded components - Bridging the knowledge gap

Injection moulding is the predominant manufacturing process enabling the production of precise and consistent polymeric parts at a high volume. The final performance of those parts is critically dependent on their melt flow history and the current approach of testing simplified specimens produced by idealized melt flow conditions to specify new or enhanced materials is therefore not sufficient, since final parts often feature a more complex geometry. The purpose of this research is to highlight this omission by conducting high velocity impact and quasi-static tensile tests on PA-12 specimens obtained from a new concept injection moulding tool. This mould allows controlled modification of the material flow by adding specific mould tool design features which lead to the creation of a weld line, flow hesitation, or combination of both of these irregular flow phenomena and is therefore an improved representation of final injection moulded components. Furthermore, test specimens representing simplified as well as more complex geometries can be obtained from the same moulded samples, guaranteeing identical applied process conditions. The occurring microstructural differences due to the diverse melt flow history are verified using optical microscopy and Differential Scanning Calorimetry

Processing of in-plant mechanically recycled PA-12

The increasing public awareness and demand for a more sustainable handling of the earth’s resources has led to the idea/ concept of a circular economy. Within this concept materials will be re-used in a closed loop system rather than being down-cycled or inappropriately managed (disposed via landfill) at the end of their life-cycle. Based on previous research, Polyamide 12 (PA-12) is a promising material candidate in the sports and leisure sector and its ability for being reprocessed via injection molding has been investigated. While other PAs tend to show a decrease in impact properties on mechanical recycling, PA-12 is shown to be able to overcome these problems when reprocessed at a higher melt temperature, yielding samples with improved impact properties compared to the primary material

PEER Testbed Study on a Laboratory Building: Exercising Seismic Performance Assessment

From 2002 to 2004 (years five and six of a ten-year funding cycle), the PEER Center organized the majority of its research around six testbeds. Two buildings and two bridges, a campus, and a transportation network were selected as case studies to “exercise” the PEER performance-based earthquake engineering methodology. All projects involved interdisciplinary teams of researchers, each producing data to be used by other colleagues in their research. The testbeds demonstrated that it is possible to create the data necessary to populate the PEER performancebased framing equation, linking the hazard analysis, the structural analysis, the development of damage measures, loss analysis, and decision variables. This report describes one of the building testbeds—the UC Science Building. The project was chosen to focus attention on the consequences of losses of laboratory contents, particularly downtime. The UC Science testbed evaluated the earthquake hazard and the structural performance of a well-designed recently built reinforced concrete laboratory building using the OpenSees platform. Researchers conducted shake table tests on samples of critical laboratory contents in order to develop fragility curves used to analyze the probability of losses based on equipment failure. The UC Science testbed undertook an extreme case in performance assessment—linking performance of contents to operational failure. The research shows the interdependence of building structure, systems, and contents in performance assessment, and highlights where further research is needed. The Executive Summary provides a short description of the overall testbed research program, while the main body of the report includes summary chapters from individual researchers. More extensive research reports are cited in the reference section of each chapter