An efficient stochastic approach to groupwise non-rigid image registration

The groupwise approach to non-rigid image registration, solving the dense correspondence problem, has recently been shown to be a useful tool in many applications, in- cluding medical imaging, automatic construction of statis- tical models of appearance and analysis of facial dynam- ics. Such an approach overcomes limitations of traditional pairwise methods but at a cost of having to search for the solution (optimal registration) in a space of much higher dimensionality which grows rapidly with the number of ex- amples (images) being registered. Techniques to overcome this dimensionality problem have not been addressed suffi- ciently in the groupwise registration literature. In this paper, we propose a novel, fast and reliable, fully unsupervised stochastic algorithm to search for optimal groupwise dense correspondence in large sets of unmarked images. The efficiency of our approach stems from novel di- mensionality reduction techniques specific to the problem of groupwise image registration and from comparative insen- sitivity of the adopted optimisation scheme (Simultaneous Perturbation Stochastic Approximation (SPSA)) to the high dimensionality of the search space. Additionally, our algo- rithm is formulated in way readily suited to implementation on graphics processing units (GPU). In evaluation of our method we show a high robust- ness and success rate, fast convergence on various types of test data, including facial images featuring large degrees of both inter- and intra-person variation, and show consid- erable improvement in terms of accuracy of solution and speed compared to traditional methods

Atrial cellular electrophysiological changes in patients with ventricular dysfunction may predispose to AF

<b>Background:</b> Left ventricular systolic dysfunction (LVSD) is a risk factor for atrial fibrillation (AF), but the atrial cellular electrophysiological mechanisms in humans are unclear. Objective This study sought to investigate whether LVSD in patients who are in sinus rhythm (SR) is associated with atrial cellular electrophysiological changes that could predispose to AF. <b>Methods:</b> Right atrial myocytes were obtained from 214 consenting patients in SR who were undergoing cardiac surgery. Action potentials or ion currents were measured using the whole-cell-patch clamp technique. <b>Results:</b> The presence of moderate or severe LVSD was associated with a shortened atrial cellular effective refractory period (ERP) (209 ± 8 ms; 52 cells, 18 patients vs 233 ± 7 ms; 134 cells, 49 patients; P <0.05); confirmed by multiple linear regression analysis. The left ventricular ejection fraction (LVEF) was markedly lower in patients with moderate or severe LVSD (36% ± 4%, n = 15) than in those without LVSD (62% ± 2%, n = 31; P <0.05). In cells from patients with LVEF ≤ 45%, the ERP and action potential duration at 90% repolarization were shorter than in those from patients with LVEF > 45%, by 24% and 18%, respectively. The LVEF and ERP were positively correlated (r = 0.65, P <0.05). The L-type calcium ion current, inward rectifier potassium ion current, and sustained outward ion current were unaffected by LVSD. The transient outward potassium ion current was decreased by 34%, with a positive shift in its activation voltage, and no change in its decay kinetics. <b>Conclusion:</b> LVSD in patients in SR is independently associated with a shortening of the atrial cellular ERP, which may be expected to contribute to a predisposition to AF

Tests for exponentiality against NBUE alternatives: a Monte Carlo comparison

Testing of various classes of life distributions has been addressed in the literature for more than 45 years. In this paper, we consider the problem of testing exponentiality (which essentially implies no ageing) against positive ageing which is captured by the fairly large class of new better than used in expectation (NBUE) distributions. These tests of exponentiality against NBUE alternatives are discussed and compared. The empirical size of the tests is obtained by simulations. Power comparisons for different popular alternatives are done using Monte Carlo simulations. These comparisons are made for both small and large sample sizes. The paper concludes with a discussion in which suggestions are made regarding the choices of the test when a particular alternative is suspected

Biotic analogies for self-organising cities

Nature has inspired generations of urban designers and planners in pursuit of harmonious and functional built environments. Research regarding self-organisation has encouraged urbanists to consider the role of bottom-up approaches in generating urban order. However, the extent to which self-organisation-inspired approaches draw directly from nature is not always clear. Here, we examined the biological basis of urban research, focusing on self-organisation. We conducted a systematic literature search of self-organisation in urban design and biology, mapped the relationship between key biological terms across the two fields and assessed the quality and validity of biological comparisons in the urban design literature. Finding deep inconsistencies in the mapping of central terms between the two fields, a preponderance for cross-level analogies and comparisons that spanned molecules to ecosystems, we developed a biotic framework to visualise the analogical space and elucidate areas where new inspiration may be sought

Cultural differences in intimacy: The influence of gender-role ideology and individualism-collectivism

Two studies examined emotional intimacy in European Canadian and Chinese Canadian dating relationships. Cultural differences in gender-role ideology and individualism–collectivism were hypothesized to differentially contribute to selfdisclosure and responsiveness, and in turn, intimacy. Study 1 revealed that Chinese Canadians’ lower intimacy relative to European Canadians was mediated by their greater gender-role traditionalism but not by their individualism or collectivism. Study 2 further linked greater gender-role traditionalism to lower self-disclosure, and in turn, lower intimacy. Results also revealed that Chinese Canadians’ lower intimacy mediated their lower relationship satisfaction and higher rate of relationship termination in Study 1, but that Chinese Canadians were not any more likely to terminate their relationships in Study 2

Cystic Fibrosis Foundation and European Cystic Fibrosis Society Survey of cystic fibrosis mental health care delivery

Background: Psychological morbidity in individuals with cystic fibrosis (CF) and their caregivers is common. The Cystic Fibrosis Foundation (CFF) and European Cystic Fibrosis Society (ECFS) Guidelines Committee on Mental Health sought the views of CF health care professionals concerning mental health care delivery. Methods: An online survey which focused on the current provision and barriers to mental health care was distributed to CF health care professionals. Results: Of the 1454 respondents, many did not have a colleague trained in mental health issues and 20% had no one on their team whose primary role was focused on assessing or treating these issues. Insufficient resources and a lack of competency were reported in relation to mental health referrals. Seventy-three percent of respondents had no experience with mental health screening. Of those who did, they utilized 48 different, validated scales. Conclusions: These data have informed the decision-making, dissemination and implementation strategies of the Mental Health Guidelines Committee sponsored by the CFF and ECFS

Relative Equilibria in the Four-Vortex Problem with Two Pairs of Equal Vorticities

We examine in detail the relative equilibria in the four-vortex problem where two pairs of vortices have equal strength, that is, \Gamma_1 = \Gamma_2 = 1 and \Gamma_3 = \Gamma_4 = m where m is a nonzero real parameter. One main result is that for m > 0, the convex configurations all contain a line of symmetry, forming a rhombus or an isosceles trapezoid. The rhombus solutions exist for all m but the isosceles trapezoid case exists only when m is positive. In fact, there exist asymmetric convex configurations when m < 0. In contrast to the Newtonian four-body problem with two equal pairs of masses, where the symmetry of all convex central configurations is unproven, the equations in the vortex case are easier to handle, allowing for a complete classification of all solutions. Precise counts on the number and type of solutions (equivalence classes) for different values of m, as well as a description of some of the bifurcations that occur, are provided. Our techniques involve a combination of analysis and modern and computational algebraic geometry

Musculoskeletal injury history is associated with lower physical and mental health in a historical cohort of former national football league players

Context: Little research has examined health-related quality of life in former National Football League (NFL) players. Objective: Examine the association of musculoskeletal injury history and current self-reported physical and mental health in former NFL players. Setting: Cross-sectional questionnaire. Patients or Other Participants: Historical cohort of 2,103 former NFL players that played at least one season between 1940 and 2001. Intervention: Players were grouped by self-reported professional career musculoskeletal injury history and whether injuries affected current health: (1) no musculoskeletal injury history; (2) musculoskeletal injury history, currently affected by injuries; and (3) musculoskeletal injury history, not currently affected by injuries. Main Outcome Measure: The Short Form 36 Measurement Model for Functional Assessment of Health and Well-Being (SF-36) yielded physical and mental health composite scores (PCS and MCS, respectively); higher scores indicated better health. Multivariable linear regression computed mean differences (MD) among injury groups. Covariates included demographics, playing history characteristics, surgical intervention for musculoskeletal injuries, and whether injury resulted in premature end to career. MD with 95% CI excluding 0.00 were deemed significant. Results: Overall, 90.3% reported at least one musculoskeletal injury during their professional football careers, of which 74.8% reported being affected by their injuries at time of survey completion. Adjusting for covariates, mean PCS in the “injury and affected” group was lower than the “no injury” (MD = −3.2; 95% CI: −4.8, −1.7) and “injury and not affected” groups (MD = −4.3; 95% CI: −5.4, −3.3); mean MCS did not differ. Conclusion: Many players reported musculoskeletal injuries, highlighting the need for developing and evaluating injury management interventions

A randomized controlled trial investigating the feasibility and adherence to an aerobic training program in healthy individuals

Context: Concussion management is moving from passive rest strategies to active interventions, including aerobic exercise therapy. Little information is available regarding the feasibility and adherence of these programs. Objectives: To determine whether an aerobic exercise training program intended for rehabilitation in people with concussion is feasible. Healthy, nonconcussed subjects were studied in this phase 1 trial. Design: Phase 1 parallel-group, randomized controlled trial in a sample of healthy (nonconcussed), recreationally active university students. Setting: Laboratory. Patients: 40 healthy university students. Methods: Participants were equally randomized to acute concussion therapy intervention (ACTIVE) training or nontraining groups. All participants completed maximal cardiopulmonary exercise tests on a stationary cycle ergometer at 2 test sessions approximately 14 days apart. During this 2-week study period, ACTIVE training participants completed six 30-minute cycling sessions, progressing from 60% to 80% of the participant's individualized maximal oxygen consumption. A subset of participants (NACTIVE = 12, Nnontraining = 11) wore physical activity monitors throughout the 2-week study period. Main Outcomes Measures: Study protocol and randomization effectiveness, exercise safety and adherence, and progressive intensity of the ACTIVE training procedures. Results: No adverse events occurred during any exercise sessions. Twelve ACTIVE training participants (60%) completed all training sessions, and every participant completed at least 4 sessions. Heart rate increased throughout the training period (P < .001), but symptom changes and training adherence remained stable despite the progressively increasing workload. ACTIVE training participants completed approximately 30 additional minutes of physical activity on training sessions days, although that was not statistically significant (P = .20). Conclusions: University-aged students were adherent to the ACTIVE training protocol. Future research should investigate the safety and feasibility of aerobic training programs in acutely concussed individuals to determine their appropriateness as a clinical rehabilitation strategy

Randomized controlled trial evaluating aerobic training and common sport-related concussion outcomes in healthy participants

Context: Aerobic exercise interventions are increasingly being prescribed for concussion rehabilitation, but whether aerobic training protocols influence clinical concussion diagnosis and management assessments is unknown. Objective: To investigate the effects of a brief aerobic exercise intervention on clinical concussion outcomes in healthy, active participants. Design: Randomized controlled clinical trial. Setting: Laboratory. Patients or Other Participants: Healthy (uninjured) participants (n ¼ 40) who exercised 3 times/week. Intervention(s): Participants were randomized into the acute concussion therapy intervention (ACTIVE) training or nontraining group. All participants completed symptom, cognitive, balance, and vision assessments during 2 test sessions approximately 14 days apart. Participants randomized to ACTIVE training completed six 30-minute exercise sessions that progressed from 60% to 80% of individualized maximal oxygen consumption (Vo2max) across test sessions, while the nontraining group received no intervention. Main Outcome Measure(s): The CNS Vital Signs standardized scores, Vestibular/Ocular Motor Screening near-point convergence distance (cm), and Graded Symptom Checklist, Balance Error Scoring System, and Standardized Assessment of Concussion total scores. Results: An interaction effect was found for total symptom score (P ¼ .01); the intervention group had improved symptom scores between sessions (session 1: 5.1 6 5.8; session 2: 1.9 6 3.6). Cognitive flexibility, executive functioning, reasoning, and total symptom score outcomes were better but composite memory, verbal memory, and near-point convergence distance scores were worse at the second session (all P values, .05). However, few changes exceeded the 80% reliable change indices calculated for this study, and effect sizes were generally small to negligible. Conclusions: A brief aerobic training protocol had few meaningful effects on clinical concussion assessment in healthy participants, suggesting that current concussion-diagnostic and -assessment tools remain clinically stable in response to aerobic exercise training. This provides normative data for future researchers, who should further evaluate the effect of ACTIVE training on clinical outcomes among concussed populations