A Flexible ADMM Algorithm for Big Data Applications

We present a Flexible Alternating Direction Method of Multipliers (F-ADMM) algorithm for solving optimization problems involving a strongly convex objective function that is separable into \(n \ge 2\) blocks, subject to (non-separable) linear equality constraints. The F-ADMM algorithm uses a Gauss–Seidel scheme to update blocks of variables, and a regularization term is added to each of the subproblems. We prove, under common assumptions, that F-ADMM is globally convergent and that the iterates converge linearly. We also present a special case of F-ADMM that is partially parallelizable, which makes it attractive in a big data setting. In particular, we partition the data into groups, so that each group consists of multiple blocks of variables. By applying F-ADMM to this partitioning of the data, and using a specific regularization matrix, we obtain a hybrid ADMM (H-ADMM) algorithm: the grouped data is updated in a Gauss–Seidel fashion, and the blocks within each group are updated in a Jacobi (parallel) manner. Convergence of H-ADMM follows directly from the convergence properties of F-ADMM. Also, we describe a special case of H-ADMM that may be applied to functions that are convex, rather than strongly convex. Numerical experiments demonstrate the practical advantages of these new algorithms.     

A highly compact packaging concept for ultrasound transducer arrays embedded in neurosurgical needles

Microsystem Technologies - State-of-the-art neurosurgery intervention relies heavily on information from tissue imaging taken at a pre-operative stage. However, the data retrieved prior to...     

Predictors of intimacy in couples' discussions of relationship injuries: An observational study.

The interpersonal process model of intimacy (H. T. Reis & P. Shaver, 1988) proposes that self-disclosure and empathic responding form the basis of intimate interactions. This study examined this model in 102 community couples who completed intimacy measures following videotaped discussions about relationship injuries occurring both within and outside the relationship. Observational assessments of self-disclosure and empathic responding, as well as their respective components, were related to self-reported ratings of post-interaction intimacy. Men's own disclosure and empathic responding predicted their feelings of intimacy, whereas women's intimacy was predicted by their partner's disclosure and empathic responding. Self-disclosure and empathic responding appear to be important behavioral determinants of intimate feelings, but the manner in which they influence intimacy differs according to gender. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improved solvation routes for the Bunsen reaction in the sulphur iodine thermochemical cycle: Part III–Bunsen reaction in molecular solvents

Operating the Bunsen reaction in a solvent has the potential to increase SI cycle efficiency and decrease operating costs. Analysing the solvent–acid mixtures produced is complicated as additional acid is formed when SO₂ comes into contact with water. Tri-n-butyl phosphate (TBP) is suitable for HI extraction; however, it is susceptible to acid catalysed dealkylation, resulting in solvent decomposition and the production of butyl iodide. Cyanex^® 923 is found to be superior to TBP in the Bunsen reaction due to its high affinity for HI. Strong orange complexes between HI, SO₂ and the phosphoryl group in Cyanex^® 923 are formed, giving good product separation, however severely hampering HI recovery. Washing the organic phase with water resulted primarily in the removal of H₂SO₄. HI could then be recovered either thermally or with a second wash step.     

The epidemiology and cost of falls requiring hospitalisation in children in Western Australia: a study using linked administrative data

OBJECTIVE: The aim of this study was to examine the epidemiology and health system cost of children's falls resulting in hospitalisation in 2003 in Western Australia. METHODS: The Injury Cost Database was used to identify children who were admitted to hospital with a falls related injury. Adjusted incidence rate ratios (IRR) of hospitalisation were modelled using Poisson regression. In-patient hospital costs were assigned using the published DRG costs for Western Australia. These costs were then extrapolated to health system costs based on previously published relative proportions. RESULTS: When adjusted for other covariates in the model males had a 53% higher incidence of falls requiring hospitalisation compared with females. Aboriginal children had a 36% higher incidence compared with their non-Aboriginal counterparts, and the incidence of falls reduced with increasing age. The total cost of in-patient hospitalisation associated with children's falls in Western Australia was A$4,554,000 with an average cost of A$1876 per case. In children aged 0-4 years and 10-14 years the highest cost resulted from falls on the flat (slips and trips). However, in children aged 5-9 years injuries resulting from falls from playground equipment resulted in both the highest cost group (A$539,000) and the highest cost per case (A$1917). The total cost to the health system of children's falls in Western Australia in 2003 were estimated to be A$21.5 million, with the total cost to the community estimated at A$108.5 million. CONCLUSION: Children's falls impose a considerable burden and cost to both the health care system and the community. This study has provided information on where the burden of risk and the majority of costs lie, namely males, Aboriginal children and for children aged 5-9 years, unlike their younger and older peers, playground equipment.     

Epitaxial graphene nucleation on C-face silicon carbide

The initial stages of epitaxial graphene growth were studied by characterization of graphene formed in localized areas on C-face 6H-SiC substrates. The graphene areas were determined to lie below the level of the surrounding substrate and showed different morphologies based on size. Employing electron channeling contrast imaging, the presence of threading screw dislocations was indicated near the centers of each of these areas. After the graphene was removed, these dislocations were revealed to lie within the SiC substrate. These observations suggest that screw dislocations act as preferred nucleation sites for graphene growth on C-face SiC.     

Environmental costs of freshwater eutrophication in England and Wales

Eutrophication has many known consequences, but there are few data on the environmental and health costs. We developed a new framework of cost categories that assess both social and ecological damage costs and policy response costs. These findings indicate the severe effects of nutrient enrichment and eutrophication on many sectors of the economy. We estimate the damage costs of freshwater eutrophication in England and Wales to be $105-160 million yr(-1) (pound 75.0-114.3 m). The policy response costs are a measure of how much is being spent to address this damage, and these amount to $77 million yr(-1) pound 54.8 m). The damage costs are dominated by seven items each with costs of $15 million yr(-1) or more: reduced value of waterfront dwellings, drinking water treatment costs for nitrogen removal, reduced recreational and amenity value of water bodies, drinking water treatment costs for removal of algal toxins and decomposition products, reduced value of nonpolluted atmosphere, negative ecological effects on biota, and net economic losses from the tourist industry. In common with other environmental problems, it would represent net value (or cost reduction) if damage was prevented at source. A variety of effective economic, regulatory, and administrative policy instruments are available for internalizing these costs.     

Clinical performance of daily disposable soft contact lenses using sustained release technology.

PURPOSE: Polyvinyl alcohol (PVA) is a successful tear film stabiliser and is widely used in comfort drops and some soft contact lens materials. A PVA-containing lens, nelfilcon A has been modified to include additional (non-functional) PVA in order to provide improved comfort. This study aims to examine the clinical performance of this nelfilcon A lens with AquaRelease (AquaRelease). METHODS: Two contralateral, investigator masked, open label, subjective and objective evaluations were conducted. The first examined the effect of adding increased molecular weight PVA to nelfilcon A (n=5), and the second compared this AquaRelease lens to ocufilcon B (n=34). The principal measures were non-invasive break-up time (NIBUT) and subjective comfort, which were assessed at the beginning and end of a week of daily wear, and three times throughout 1 day at 8, 12 and 16 h. RESULTS: All subjects successfully completed the daily wearing schedule of 16h. On initial insertion, subjective comfort and NIBUT improved for AquaRelease than original nelfilcon A lenses (p<0.05). Initial comfort was better for AquaRelease compared to ocufilcon B lenses (p=0.01); however, NIBUT was not statistically different (11.7+/-15.6s versus 8.4+/-6.8s; p=0.26). Subjective comfort decreased with time (p<0.001), but there was no significant difference between AquaRelease and ocufilcon B lenses (p=0.16). NIBUT was not significantly affected by time (p=0.56) or between lenses (p=0.33). At the end of a weeks' wear, subjective initial, end-of-day, overall comfort and vision were rated significantly better with AquaRelease than ocufilcon B (p<0.01). CONCLUSIONS: Release of additional non-functionalised PVA from the nelfilcon A lenses appears to enhance comfortable contact lens wear.     

The impact of pain in spinal cord injury: A case–control study.

Objective: To examine the impact of pain on functioning across multiple quality of life QOL) domains among individuals with spinal cord injury (SCI). Design: A case–control design that matched 2 groups (i.e., extreme pain interference and no pain interference) case for case on age (i.e., within 10 years), education, gender, race, marital status, primary occupation, and impairment level. Etiology of SCI and injury duration, although not specifically matched, were the same in 84% and 91% of the cases, respectively. Participants: Individuals with traumatic-onset SCI from the National Spinal Cord Injury database (n?=?86 matched pairs). Outcome Measures: Satisfaction With Life Scale, Craig Handicap Assessment and Reporting Technique, and Short Form SF-12. Results: The extreme pain interference group reported a significantly lower overall QOL and had higher total handicap scores than the no pain interference group. Areas of handicap most influenced by pain were mobility, social integration, and economic self-sufficiency. The extreme pain interference group also reported significantly lower physical and mental health than the no pain interference group. Conclusions: Pain has a consistent detrimental impact on functioning across multiple QOL domains even after controlling for multiple demographic and medical characteristics known to be associated with self-reported QOL. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using client feedback in psychotherapy training: An analysis of its influence on supervision and counselor self-efficacy.

Tracking client outcome and the therapeutic relationship across treatment (i.e., client feedback) has become a recommended practice for clinicians. This study investigated whether the utility of this practice would extend to trainees if the data gained from clients was provided to their supervisor for use within supervision. Trainees (N = 28) were assigned to a continuous feedback condition or no-feedback condition for 1 academic year. Results indicated that trainees in both conditions demonstrated better client outcomes at the end of their practicum training than at the beginning, but those in the feedback condition improved more. However, those in the feedback condition did not rate the supervisory alliance or satisfaction with the supervision process differently. The relationship between counselor self-efficacy and outcome was stronger for trainees in the feedback condition than for those in the no-feedback condition, perhaps indicating that feedback may facilitate a more accurate assessment of one’s skills. Implications of how counseling self-efficacy, the supervisory alliance, and satisfaction with supervision are related to effective supervision are addressed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)