The valuation of clean spread options: linking electricity, emissions and fuels

The purpose of the paper is to present a new pricing method for clean spread options, and to illustrate its main features on a set of numerical examples produced by a dedicated computer code. The novelty of the approach is embedded in the use of a structural model as opposed to reduced-form models which fail to capture properly the fundamental dependencies between the economic factors entering the production process

The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes

Background: The most common cause of Gram-negative bacterial neonatal meningitis is E. coli K1. It has a mortality rate of 10–15%, and neurological sequelae in 30– 50% of cases. Infections can be attributable to nosocomial sources, however the pre-colonisation of enteral feeding tubes has not been considered as a specific risk factor. Methods: Thirty E. coli strains, which had been isolated in an earlier study, from the residual lumen liquid and biofilms of neonatal nasogastric feeding tubes were genotyped using pulsed-field gel electrophoresis, and 7-loci multilocus sequence typing. Potential pathogenicity and biofilm associated traits were determined using specific PCR probes, genome analysis, and in vitro tissue culture assays. Results: The E. coli strains clustered into five pulsotypes, which were genotyped as sequence types (ST) 95, 73, 127, 394 and 2076 (Achman scheme). The extra-intestinal pathogenic E. coli (ExPEC) phylogenetic group B2 ST95 serotype O1:K1:NM strains had been isolated over a 2 week period from 11 neonates who were on different feeding regimes. The E. coli K1 ST95 strains encoded for various virulence traits associated with neonatal meningitis and extracellular matrix formation. These strains attached and invaded intestinal, and both human and rat brain cell lines, and persisted for 48 h in U937 macrophages. E. coli STs 73, 394 and 2076 also persisted in macrophages and invaded Caco-2 and human brain cells, but only ST394 invaded rat brain cells. E. coli ST127 was notable as it did not invade any cell lines. Conclusions: Routes by which E. coli K1 can be disseminated within a neonatal intensive care unit are uncertain, however the colonisation of neonatal enteral feeding tubes may be one reservoir source which could constitute a serious health risk to neonates following ingestion

Strategy Selection in Structured Populations

Evolutionary game theory studies frequency dependent selection. The fitness of a strategy is not constant, but depends on the relative frequencies of strategies in the population. This type of evolutionary dynamics occurs in many settings of ecology, infectious disease dynamics, animal behavior and social interactions of humans. Traditionally evolutionary game dynamics are studied in well-mixed populations, where the interaction between any two individuals is equally likely. There have also been several approaches to study evolutionary games in structured populations. In this paper we present a simple result that holds for a large variety of population structures. We consider the game between two strategies, A and B, described by the payoff matrix View the MathML source. We study a mutation and selection process. For weak selection strategy A is favored over B if and only if σa+b>c+σd. This means the effect of population structure on strategy selection can be described by a single parameter, σ. We present the values of σ for various examples including the well-mixed population, games on graphs, games in phenotype space and games on sets. We give a proof for the existence of such a σ, which holds for all population structures and update rules that have certain (natural) properties. We assume weak selection, but allow any mutation rate. We discuss the relationship between σ and the critical benefit to cost ratio for the evolution of cooperation. The single parameter, σ, allows us to quantify the ability of a population structure to promote the evolution of cooperation or to choose efficient equilibria in coordination games.MathematicsOrganismic and Evolutionary Biolog

Cervical lymph node metastasis in high-grade transformation of head and neck adenoid cystic carcinoma: a collective international review

Adenoid cystic carcinoma (AdCC) is among the most common malignant tumors of the salivary glands. It is characterized by a prolonged clinical course, with frequent local recurrences, late onset of metastases and fatal outcome. High-grade transformation (HGT) is an uncommon phenomenon among salivary carcinomas and is associated with increased tumor aggressiveness. In AdCC with high-grade transformation (AdCC-HGT), the clinical course deviates from the natural history of AdCC. It tends to be accelerated, with a high propensity for lymph node metastasis. In order to shed light on this rare event and, in particular, on treatment implications, we undertook this review: searching for all published cases of AdCC-HGT. We conclude that it is mandatory to perform elective neck dissection in patients with AdCC-HGT, due to the high risk of lymph node metastases associated with transformation

Valencia bridge fire tests: Validation of simplified and advanced numerical approaches to model bridge fire scenarios

[EN] Bridge fires are a major concern and the subject of many studies that use numerical models. However, experimental studies are still required to test the validity of these numerical models and improve their accuracy. This paper uses temperature results of the Valencia bridge fire tests carried out at the Universitat Politecnica de Valencia, in Valencia (Spain) to calibrate the fire models that constitute the first step in modeling any bridge fire event. The calibration is carried out by both a simplified approach (Heskestad and Hamada's correlation) and advanced numerical models (Computational Fluid Dynamics models built with the Fire Dynamics Simulator -FDS- software). The Valencia bridge fire tests involved four fire scenarios under a composite bridge with Heat Release Rate (HRR) values between 361 and 1352 kW. The results show that applying Heskestad and Hamada's correlation gave good results when used within its limits of application (HRR < 0.764 MW) but did not work well beyond them, which means it would be suitable for planning reduced scale bridge fire tests but not in the analysis of real bridge fires. On the other hand, FDS provides good predictions of the temperatures and can be used to study bridge fire responses. This work is therefore an important step forward in the study of bridge fires and towards the improvement of the resilience of infrastructure networks vis-a-vis fire hazards. It also highlights the problems that can arise in fire tests in the open air, the influence of the wind being of critical importance.Funding for this research was provided by the Spanish Ministry of Science and Innovation (Research Project BIA 2011-27104). The authors are grateful to the Infrastructure and Safety departments of the Universitat Politecnica de Valencia and the City of Valencia Fire Department (Cuerpo de Bomberos de Valencia), which provided crucial support in conducting the tests.Alós-Moya, J.; Paya-Zaforteza, I.; Hospitaler Pérez, A.; Loma-Ossorio, E. (2019). Valencia bridge fire tests: Validation of simplified and advanced numerical approaches to model bridge fire scenarios. Advances in Engineering Software (Online). 128:55-68. https://doi.org/10.1016/j.advengsoft.2018.11.003S556812

One-year weight losses in the TRAMOMTANA Study. A Randomized Controlled Trial.

Abstract BACKGROUND: Morbid obesity is a major health problem and bariatric surgery is currently the most effective therapy available to induce weight loss in these patients. This report describes 1-year changes in weight and metabolic parameters, in a trial designed to examine the effects of a non-surgical approach, Intensive Life style Intervention (ILI) on the therapy of morbid obesity. METHODS: The primary outcome was change in body weight. Patients were randomized to ILI (n=60) or conventional obesity therapy (COT) (n=46). The ILI group received behavioural therapy and nutritional/physical activity counseling. The COT group received the standard medical treatment available for these patients. A third group consisted of the patients already included in our bariatric surgery waiting list (n=37). FINDINGS: We present here one year data showing that patients who received ILI with no restrictions in calorie intake had a greater percentage of weight loss than patients receiving COT (-11.58% vs. -0.4%; p<.001). Importantly, 31.4% of patients included in the ILI group were not morbidly obese after 6 months of intervention. This number increased to 42.8% after 12 months of intervention. INTERPRETATION: ILI was associated with significant weight loss compared to COT in a group of morbidly obese patients. The weight loss effect was already obtained after 6 months of ILI intervention. These results seriously question the efficacy of the COT approach to morbid obesity. Furthermore, they underscore the use of ILI programs in the hospital setting to effectively treat morbidly obese patients and might help to reduce the number of candidate patients for bariatric surgery

Vitamin D in the prevention of exacerbations of asthma in preschoolers (DIVA): Protocol for a multicentre randomised placebo-controlled triple-blind trial

Introduction Preschoolers have the highest rate of emergency visits and hospitalisations for asthma exacerbations of all age groups, with most triggered by upper respiratory tract infections (URTIs) and occurring in the fall or winter. Vitamin D insufficiency is highly prevalent in Canadian preschoolers with recurrent asthma exacerbations, particularly in winter. It is associated with more URTIs and, in patients with asthma, more oral corticosteroid (OCS) use. Although evidence suggests that vitamin D supplements significantly decrease URTIs and asthma exacerbations requiring OCS, there is insufficient data in preschoolers. This study aims to determine the impact of vitamin D 3 supplementation on exacerbations requiring OCS, in preschoolers with recurrent URTI-induced asthma exacerbations. Methods and analysis This is a phase III, randomised, triple-blind, placebo-controlled, parallel-group multicentre trial of vitamin D 3 supplementation in children aged 1-5 years, with asthma triggered by URTIs and a recent history of frequent URTIs and OCS use. Children (n=865) will be recruited in the fall and early winter and followed for 7 months. They will be randomised to either the (1) intervention: two oral boluses of 100 000 international unit (IU) vitamin D 3 (3.5 months apart) with 400 IU vitamin D 3 daily; or (2) control: identical placebo boluses with daily placebo. The primary outcome is the number of exacerbations requiring OCS per child, documented by medical and pharmacy records. Secondary outcomes include number of laboratory-confirmed viral URTIs, exacerbation duration and severity, parent functional status, healthcare use, treatment deintensification, cost and safety. Ethics and dissemination This study has received ethical approval from all sites. Results will be disseminated via international conferences and manuscripts targeting paediatricians and respirologists, and to families of asthmatic children via our Quebec parents-partners outreach programme. If proven effective, findings may markedly influence the management of URTI-induced asthma in high-morbidity preschoolers and could be directly implemented into practice with an update to clinical guidelines. Trial registration number NCT03365687