Multiplier-continuation algorthms for constrained optimization

Several path following algorithms based on the combination of three smooth penalty functions, the quadratic penalty for equality constraints and the quadratic loss and log barrier for inequality constraints, their modern counterparts, augmented Lagrangian or multiplier methods, sequential quadratic programming, and predictor-corrector continuation are described. In the first phase of this methodology, one minimizes the unconstrained or linearly constrained penalty function or augmented Lagrangian. A homotopy path generated from the functions is then followed to optimality using efficient predictor-corrector continuation methods. The continuation steps are asymptotic to those taken by sequential quadratic programming which can be used in the final steps. Numerical test results show the method to be efficient, robust, and a competitive alternative to sequential quadratic programming

Lessons from dynamic cadaver and invasive bone pin studies: do we know how the foot really moves during gait?

Background: This paper provides a summary of a Keynote lecture delivered at the 2009 Australasian Podiatry Conference. The aim of the paper is to review recent research that has adopted dynamic cadaver and invasive kinematics research approaches to better understand foot and ankle kinematics during gait. It is not intended to systematically cover all literature related to foot and ankle kinematics (such as research using surface mounted markers). Since the paper is based on a keynote presentation its focuses on the authors own experiences and work in the main, drawing on the work of others where appropriate Methods: Two approaches to the problem of accessing and measuring the kinematics of individual anatomical structures in the foot have been taken, (i) static and dynamic cadaver models, and (ii) invasive in-vivo research. Cadaver models offer the advantage that there is complete access to all the tissues of the foot, but the cadaver must be manipulated and loaded in a manner which replicates how the foot would have performed when in-vivo. The key value of invasive in-vivo foot kinematics research is the validity of the description of foot kinematics, but the key difficulty is how generalisable this data is to the wider population. Results: Through these techniques a great deal has been learnt. We better understand the valuable contribution mid and forefoot joints make to foot biomechanics, and how the ankle and subtalar joints can have almost comparable roles. Variation between people in foot kinematics is high and normal. This includes variation in how specific joints move and how combinations of joints move. The foot continues to demonstrate its flexibility in enabling us to get from A to B via a large number of different kinematic solutions. Conclusion: Rather than continue to apply a poorly founded model of foot type whose basis is to make all feet meet criteria for the mechanical 'ideal' or 'normal' foot, we should embrace variation between feet and identify it as an opportunity to develop patient-specific clinical models of foot function

Sustainable Management of Popular Culture Tourism Destinations: A Critical Evaluation of the Twilight Saga Servicescapes

Popular culture tourism destinations are made up of constructed realities transforming local communities into fictional servicescapes. The purpose of this study is to demonstrate how the unpacking of a key concept (servicescape), applied to destination management, can support the transition to sustainable destination development in the face of popular culture tourism. The aim is to unpack the servicescape concept by exploring how it is constructed focusing on Twilight Saga representations and production processes at four destinations. The data consists of photographs and video clips of the servicescapes and interviews with key stakeholders. The findings support previous servicescape research dimensions and elements but also identify critical areas of power, control, and conflict when introducing a process approach to the servicescape concept. The study provides insights into the complex exchanges that take place in the development of servicescapes at popular culture tourism destinations. The study thereby contributes to an elaborated and holistic servicescape model, stressing the importance of strategic design and local stakeholders’ early involvement in the preproduction of popular culture tourism phenomena.publishedVersio

Viscoelastic impact between a cylindrical striker and a long cylindrical bar

International audienceAxial impact between a cylindrical striker of finite length and a long cylindrical bar, both of linearly viscoelastic materials, is considered under uni-axial conditions. General results are derived for the impact force, the particle velocity and the strain in the bar in terms of closed-contour integrals suitable for numerical evaluation. Such results are derived also for the transfer of momentum and energy from the striker to the bar. Numerical results for elastic and viscoelastic impact of a striker and a bar with different cross-sectional areas are compared. In viscoelastic impact, unlike elastic impact, the duration of impact may be finite but larger than two transit times for a wave front through the striker due to the for-mation of a tail after the main pulse. Furthermore, repeated contacts and separations of the striker and the bar may occur within a range of striker-to bar characteristic impedance ratios smaller than one. In viscoelastic impact, the duration of impact is at least as long and the momentum and energy transferred are at most as large as in elastic impact. Strains measured at three locations of a PMMA bar impacted by PMMA strikers of three different lengths agree well with the theoretical results

Unmet challenges in septoplasty-nordic studies from a uniform healthcare and geographical area

PurposeNasal septoplasty is one of the most common surgical procedures in otorhinolaryngology and optimising both patient selection and the surgery is a challenge. The Nordic countries have similar public healthcare systems and comparable populations in terms of size. MethodsThis is a review of studies of outcome and predictors related to septoplasty from Denmark, Finland, Norway and Sweden, published during the last decade. The aim of this review was to identify areas in need of further research to meet the challenges of septoplasty in the Nordic countries with reference to international data. ResultsPostoperative patient satisfaction at 6-12 months was reported in around 2/3 of the patients and well in line with international data. Patients with more severe symptoms had a higher chance of improvement. Lack of standardisation in patient selection, surgical methods and skills, and follow up procedures, still makes it difficult to explain the 25% failure rate in septoplasty surgery. ConclusionThis review of the Nordic studies from the last decade shows that septoplasty in general is effective in relieving nasal obstruction. There is a need for studies addressing the standardisation of diagnostic tools and algorithms and the systematic and continuous implementation of follow-up of the surgical results at both departmental and personal level. This includes an awareness of how surgical skills in septoplasty are obtained and maintained.Peer reviewe

Socioeconomic risk, parenting during the preschool years and child health age 6 years

Parent–child relationships and parenting processes are emerging as potential life course determinants of health. Parenting is socially patterned and could be one of the factors responsible for the negative effects of social inequalities on health, both in childhood and adulthood. This study tests the hypothesis that some of the effect of socioeconomic risk on health in mid childhood is transmitted via early parenting. Methods: Prospective cohort study in 10 USA communities involving 1041 mother/ child pairs, selected at birth at random with conditional sampling. Exposures: income, maternal education, maternal age, lone parenthood, ethnic status and objective assessments of mother child interaction in the first 4 years of life covering warmth, negativity and positive control. Outcomes: mother’s report of child’s health in general at 6 years. Modelling: multiple regression analyses with statistical testing of mediational processes. Results: All five indicators of socioeconomic status (SES) were correlated with all three measures of parenting, such that low SES was associated with poor parenting. Among the measures of parenting maternal warmth was independently predictive of future health, and among the socioeconomic variables maternal education, partner presence and ‘other ethnic group’ proved predictive. Measures of parenting significantly mediated the impact of measures of SES on child health. Conclusions: Parenting mediates some, but not all of the detectable effects of socioeconomic risk on health in childhood. As part of a package of measures that address other determinants, interventions to support parenting are likely to make a useful contribution to reducing childhood inequalities in health

Trends in Real Food Prices in Six Sub-Saharan African Countries

Demand and Price Analysis, Downloads July 2008-July 2009: 12,

A unique biofilm in human deep mycoses: fungal amyloid is bound by host serum amyloid P component

Background/Objectives We have demonstrated the presence of Candida cell surface amyloids that are important in aggregation of fungi and adherence to tissue. Fungal amyloid was present in invasive human candidal infections and host serum amyloid P component (SAP) bound to the fungal amyloid. SAP is a protease-resistant glycoprotein that binds avidly to amyloid and interferes with host defence, especially against bacterial pathogens for which neutrophils are important. In this study, we investigated whether biofilm of fungal amyloid and SAP was a feature of other disseminated fungal infections. Methods Tissue specimens from 15 autopsies were systematically evaluated with multiple histochemical stains including thioflavin T and Congo red (dyes that stain amyloid), as well as antibody to SAP. We studied specimens with disseminated aspergillosis, mucormycosis and coccidioidomycosis. The structure of the lesions, host inflammatory cells and the presence of fungal amyloid and SAP were determined. Results The structure of the lesions was characteristic in aspergillosis (‘starburst’) and mucormycosis (closely apposed bundles of hyphae). Host inflammatory cells were absent or few in number within these lesions. In Coccidioides lesions, host inflammation was sparse as well. Fungal amyloid was a prominent feature of all lesions along with abundant SAP bound to hyphae and spherules. Fungal amyloid and SAP perhaps contributed to persistence in caseous necrosis lesions. SAP also bound to Aspergillus and Mucorales amyloid in vitro. Conclusions A biofilm including amyloid and SAP is present in invasive fungal infections. This biofilm may dampen host defence leading to the characteristic sparse inflammatory reaction found in these infections