3,080 research outputs found

    Testing the accuracy of Foti's dental age estimation methods on a London UK sample

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    Background and aim: Tooth development and eruption are widely used in assessing dental age estimation, and one of the methods in using tooth development and eruption is Foti's method. However, the population used in the original study was French. Therefore, the aim of this study was to test the accuracy of Foti's four dental age estimation regression models against the East London population, mainly of the Bangladeshi and Caucasian ethnicity. These count the number of erupted teeth and tooth germs using a radiograph (Foti 1), absence of a radiograph (Foti 2), maxillary erupted teeth (Foti 3) and mandibular erupted teeth (Foti 4). Methods: The test sample was archived panoramic radiographs of 754 healthy patients aged 6–20 years (380 males and 374 females). The difference between dental and chronological ages was tested using a t-test. The mean absolute difference was also calculated for all models. The most accurate method was defined as the smallest mean difference, smallest standard deviation (SD) and mean absolute difference between dental and chronological ages. Results: Foti model 2 was most accurate with a mean difference of 0.11 years (SD 1.70 years) and a mean absolute difference of 1.33 years. Models 3 (maxillary erupted teeth) and 4 (mandibular erupted teeth) were marginally less accurate, whilst model 1 (radiograph) overestimated age on average by more than 5 years. Conclusion: Our findings show that estimating age using erupting teeth was most accurate using Foti model 2 (least bias)

    Barriers to social enterprise growth

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    This study investigates barriers to social enterprise growth. The research employs qualitative case study data gathered from young social enterprises to examine the interplay between social enterprise and individual, organizational and institutional barriers to growth. We find that social enterprise barriers to growth are based on values differences, business models and institutional norms. We theorize three strategic responses to overcome barriers to growth: values-based decision-making, leveraging social mission, and anchoring.We would like to gratefully acknowledge the financial support provided by the Oikos Foundation for Economy and Ecology and the Swiss National Science Foundation

    Charged Repetitive Protein Sequences in the Modification of the Host Red Blood Cell by the Malaria Parasite

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    During the symptomatic asexual stage of its life cycle, the malaria parasite P. falciparum exports proteins into the host erythrocyte to modulate its properties. Many exported proteins are targeted to the cell periphery where they affect cell deformability, adhesion, and nutrient import. These changes are implicated in causing severe manifestations of the disease. We have identified novel protein modules which are capable of targeting to the periphery of the red blood cell and which may be involved in modulating these important changes. These were all composed of lysine-rich repetitive sequences, which were shown to be functional in ten proteins altogether, including one protein from the zoonotic P. knowlesi species. Some were found in proteins known to modulate erythrocyte rigidity and cytoadhesion while others were previously uncharacterised. One protein, the glutamic acid-rich protein (GARP), contains three lysine-rich repeating sequences with a peripheral-targeting function. Such repetitive sequences are highly enriched in P. falciparum yet very few have been shown to be functional. Targeting efficiency was shown to be directly affected by the number of repeats present; suggesting that expansion of short non-functional lysine-rich sequences can lead to the de novo formation of localisation sequences. This is observed by comparing the protein sequences of closely related Plasmodium species where repeat expansion has led to functional targeting sequences in some but not others. Additionally, we show that the length of many functional repetitive sequences is highly variable between parasite isolates. Repeat expansion and contraction may allow the parasite to rapidly adapt to selective pressure. Another domain was identified in proteins involved in modulating cytoadhesion and rigidity of host cells in P. falciparum and is conserved across primateinfecting Plasmodium species. Identifying the roles of these novel modules will expand our understanding of parasite-induced erythrocyte modifications and the underlying mechanisms responsible for severe malaria

    A dynamic spatial model of conflict escalation

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    In both historical and modern conflicts, space plays a critical role in how interactions occur over time. Despite its importance, the spatial distribution of adversaries has often been neglected in mathematical models of conflict. In this paper, we propose an entropy-maximising spatial interaction method for disaggregating the impact of space, employing a general notion of ‘threat’ between two adversaries. This approach addresses a number of limitations that are associated with partial differential equation approaches to spatial disaggregation. We use this method to spatially disaggregate the Richardson model of conflict escalation, and then explore the resulting model with both analytical and numerical treatments. A bifurcation is identified that dramatically influences the resulting spatial distribution of conflict and is shown to persist under a range of model specifications. Implications of this finding for real-world conflicts are discussed

    The outsourcing of social care in Britain : what does it mean for voluntary sector workers?

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    While recent decades have witnessed a growth in the outsourcing of public services in Britain, the post-1997 UK Labour governments have sought to put in place mechanisms aimed at encouraging long-term collaborative contracting relationships marked by less reliance on cost-based competition. This article explores empirically how far these mechanisms have achieved their aims and thereby acted to protect the employment conditions of staff, and links this exploration to debates concerning the employment implications of organizational reforms within public sectors internationally. It concludes that in terms of bringing income security to the voluntary sector and stability to employment terms and conditions these efforts have been unsuccessful, and consequently casts doubts on more optimistic interpretations of the employment effects of organizational restructuring in the British public sector

    Exercise-based rehabilitation for heart failure: systematic review and meta-analysis

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    This is the final version of the article. Available from BMJ Publishing Group via the DOI in this record.OBJECTIVE: To update the Cochrane systematic review of exercise-based cardiac rehabilitation (CR) for heart failure. METHODS: A systematic review and meta-analysis of randomised controlled trials was undertaken. MEDLINE, EMBASE and the Cochrane Library were searched up to January 2013. Trials with 6 or more months of follow-up were included if they assessed the effects of exercise interventions alone or as a component of comprehensive CR programme compared with no exercise control. RESULTS: 33 trials were included with 4740 participants predominantly with a reduced ejection fraction (<40%) and New York Heart Association class II and III. Compared with controls, while there was no difference in pooled all-cause mortality between exercise CR with follow-up to 1 year (risk ratio (RR) 0.93; 95% CI 0.69 to 1.27, p=0.67), there was a trend towards a reduction in trials with follow-up beyond 1 year (RR 0.88; 0.75 to 1.02, 0.09). Exercise CR reduced the risk of overall (RR 0.75; 0.62 to 0.92, 0.005) and heart failure-specific hospitalisation (RR 0.61; 0.46 to 0.80, 0.0004) and resulted in a clinically important improvement in the Minnesota Living with Heart Failure questionnaire (mean difference: -5.8 points, -9.2 to -2.4, 0.0007). Univariate meta-regression analysis showed that these benefits were independent of the type and dose of exercise CR, and trial duration of follow- up, quality or publication date. CONCLUSIONS: This updated Cochrane review shows that improvements in hospitalisation and health-related quality of life with exercise-based CR appear to be consistent across patients regardless of CR programme characteristics and may reduce mortality in the longer term. An individual participant data meta-analysis is needed to provide confirmatory evidence of the importance of patient subgroup and programme level characteristics (eg, exercise dose) on outcome.This publication presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (Grant Reference Number RP-PG-1210-12004)

    Layered Structures of Ti-6Al-4V Alloy and Metal Matrix Composites on Its Base Joint by Diffusion Bonding and Friction Welding

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    Metallic layered structures demonstrate an advanced set of characteristics that combine different properties not found within homogenous bulk materials. Powder metallurgy (PM) is proven to be the most efficient way of fabrication of layered structures, including highly rated structures of Ti alloys. Residual porosity, however, remains one of the biggest problems of titanium-based PM products and this can adversely affect the mechanical properties and performance of the structural parts. Post-sintering hot deformation is a common way to control the porosity of metallic materials. Traditional thermomechanical processing like hot rolling, however, could not be applied on multi-layered structures due to the disparity of the different layers’ plastic flow. Separate processing of high performance individual layers to reach their best parameters, followed by post processing bonding of the mating subcomponents is a credible pathway for fabrication of the layered materials with highly optimized properties of each individual layer. In this study we used diffusion bonding (DB) and friction welding to join the parts made of Ti-6Al-4V alloy and metal matrix composites on the base of this alloy reinforced with 10% of either TiB or TiC. Parts were fabricated using blended elemental PM. Different protocols were used to join the materials: DB welding via rotational friction (RFW) and linear friction (LFW) as well as different geometries of mating subcomponents were tested. Structure characterization of the joints using light optical microscopy, SEM, EDS, EBSD as well as mechanical tests were performed. All used protocols were generally successful in bonding the parts made of Ti-64 alloy and composites on its base. The potential of DB, RFW and LFW of Ti-6Al-4V alloy and its MMC are discussed

    Achieving optimal adherence to medical therapy by telehealth: Findings from the ORBITA medication adherence sub-study

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    INTRODUCTION: The ORBITA trial of percutaneous coronary intervention (PCI) versus a placebo procedure for patients with stable angina was conducted across six sites in the United Kingdom via home monitoring and telephone consultations. Patients underwent detailed assessment of medication adherence which allowed us to measure the efficacy of the implementation of the optimization protocol and interpretation of the main trial endpoints. METHODS: Prescribing data were collected throughout the trial. Self-reported adherence was assessed, and urine samples collected at pre-randomization and at follow-up for direct assessment of adherence using high-performance liquid chromatography with tandem mass spectrometry (HPLC MS/MS). RESULTS: Self-reported adherence was >96% for all drugs in both treatment groups at both stages. The percentage of samples in which drug was detected at pre-randomization and at follow-up in the PCI versus placebo groups respectively was: clopidogrel, 96% versus 90% and 98% versus 94%; atorvastatin, 95% versus 92% and 92% versus 91%; perindopril, 95% versus 97% and 85% versus 100%; bisoprolol, 98% versus 99% and 96% versus 97%; amlodipine, 99% versus 99% and 94% versus 96%; nicorandil, 98% versus 96% and 94% versus 92%; ivabradine, 100% versus 100% and 100% versus 100%; and ranolazine, 100% versus 100% and 100% versus 100%. CONCLUSIONS: Adherence levels were high throughout the study when quantified by self-reporting methods and similarly high proportions of drug were detected by urinary assay. The results indicate successful implementation of the optimization protocol delivered by telephone, an approach that could serve as a model for treatment of chronic conditions, particularly as consultations are increasingly conducted online
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