393 research outputs found
A Hedged Monte Carlo Approach to Real Option Pricing
In this work we are concerned with valuing optionalities associated to invest
or to delay investment in a project when the available information provided to
the manager comes from simulated data of cash flows under historical (or
subjective) measure in a possibly incomplete market. Our approach is suitable
also to incorporating subjective views from management or market experts and to
stochastic investment costs. It is based on the Hedged Monte Carlo strategy
proposed by Potters et al (2001) where options are priced simultaneously with
the determination of the corresponding hedging. The approach is particularly
well-suited to the evaluation of commodity related projects whereby the
availability of pricing formulae is very rare, the scenario simulations are
usually available only in the historical measure, and the cash flows can be
highly nonlinear functions of the prices.Comment: 25 pages, 14 figure
Patients’ Perspectives, Experiences, and Concerns With Perianal Fistulae:Insights From Online Targeted-Disease Forums
Background: Perianal fistulae can undermine physical, emotional, and social well-being in patients with Crohn’s disease and are challenging to manage. Social media offers a rich opportunity to gain an in-depth understanding of the impact of perianal fistulae on patients’ daily lives outside of controlled environments. In this study, we conducted social media analytics to examine patients’ experiences with perianal fistulae and assessed the impact of perianal fistulae on patients’ behavior and overall well-being. Methods: We used a mixed-method approach to examine 119 986 publicly available posts collected from 10 Crohn’s disease forums in the United States between January 01, 2010 and January 01, 2020. Discussions related to Crohn’s perianal fistulae were retrieved. We randomly selected 700 posts and qualitatively analyzed them using an inductive thematic approach. We then applied a latent Dirichlet allocation probabilistic topic model to explore themes in an unsupervised manner on the collection of 119 986 posts. Results: In the qualitative analysis, 5 major themes were identified: (1) burden of perianal fistula; (2) challenges associated with treatment; (3) online information seeking and sharing; (4) patient experiences with treatments; and (5) patients’ apprehension about treatments. In the quantitative analysis, the percentages of posts related to the major themes were (1) 20%, (2) 29%, (3) 66%, and (4) 28%, while the topic model did not identify theme 5. Conclusions: Social media reveals a dynamic range of themes governing patients’ perspectives and experiences with Crohn’s perianal fistulae. In addition to the biopsychosocial burden, patients frequently express dissatisfaction with current treatments and often struggle to navigate among available management options.</p
Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using x-ray computed tomography
We used X-ray computed tomography (CT), microscopy and hardness measurements to study Al–Si10–Mg produced by selective laser melting (SLM). Specimens were subject to a series of heat treatments including annealing and precipitation hardening. The specimen interiors were imaged with X-ray CT, allowing the non-destructive quantification and characterisation of pores, including their spatial distribution. The specimens had porosities less than 0.1%, but included some pores with effective cross-sectional diameters up to 260 μm. The largest pores were highly anisotropic, being flat and lying in the plane normal to the build direction. Annealing cycles caused significant coarsening of the microstructure and a reduction of the hardness from (114 ± 3) HV, in the as-built state, to (45 ± 1) HV, while precipitation hardening increased this to a final hardness of (59 ± 1) HV. The pore size and shape distributions were unaffected by the heat treatments. We demonstrate the applicability of CT measurements and quantitative defect analysis for the purposes of SLM process monitoring and refinement
The SPECTRUM Consortium: a new UK Prevention Research Partnership consortium focussed on the commercial determinants of health, the prevention of non-communicable diseases, and the reduction of health inequalities
The main causes of non-communicable diseases (NCDs), health inequalities and health inequity include consumption of unhealthy commodities such as tobacco, alcohol and/or foods high in fat, salt and/or sugar. These exposures are preventable, but the commodities involved are highly profitable. The economic interests of ‘Unhealthy Commodity Producers’ (UCPs) often conflict with health goals but their role in determining health has received insufficient attention. In order to address this gap, a new research consortium has been established. This open letter introduces the SPECTRUM (Shaping Public hEalth poliCies To Reduce ineqUalities and harM) Consortium: a multi-disciplinary group comprising researchers from 10 United Kingdom (UK) universities and overseas, and partner organisations including three national public health agencies in Great Britain (GB), five multi-agency alliances and two companies providing data and analytic support. Through eight integrated work packages, the Consortium seeks to provide an understanding of the nature of the complex systems underlying the consumption of unhealthy commodities, the role of UCPs in shaping these systems and influencing health and policy, the role of systems-level interventions, and the effectiveness of existing and emerging policies. Co-production is central to the Consortium’s approach to advance research and achieve meaningful impact and we will involve the public in the design and delivery of our research. We will also establish and sustain mutually beneficial relationships with policy makers, alongside our partners, to increase the visibility, credibility and impact of our evidence. The Consortium’s ultimate aim is to achieve meaningful health benefits for the UK population by reducing harm and inequalities from the consumption of unhealthy commodities over the next five years and beyond
Identification of independent association signals and putative functional variants for breast cancer risk through fine-scale mapping of the 12p11 locus.
BACKGROUND: Multiple recent genome-wide association studies (GWAS) have identified a single nucleotide polymorphism (SNP), rs10771399, at 12p11 that is associated with breast cancer risk. METHOD: We performed a fine-scale mapping study of a 700 kb region including 441 genotyped and more than 1300 imputed genetic variants in 48,155 cases and 43,612 controls of European descent, 6269 cases and 6624 controls of East Asian descent and 1116 cases and 932 controls of African descent in the Breast Cancer Association Consortium (BCAC; http://bcac.ccge.medschl.cam.ac.uk/ ), and in 15,252 BRCA1 mutation carriers in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Stepwise regression analyses were performed to identify independent association signals. Data from the Encyclopedia of DNA Elements project (ENCODE) and the Cancer Genome Atlas (TCGA) were used for functional annotation. RESULTS: Analysis of data from European descendants found evidence for four independent association signals at 12p11, represented by rs7297051 (odds ratio (OR) = 1.09, 95 % confidence interval (CI) = 1.06-1.12; P = 3 × 10(-9)), rs805510 (OR = 1.08, 95 % CI = 1.04-1.12, P = 2 × 10(-5)), and rs1871152 (OR = 1.04, 95 % CI = 1.02-1.06; P = 2 × 10(-4)) identified in the general populations, and rs113824616 (P = 7 × 10(-5)) identified in the meta-analysis of BCAC ER-negative cases and BRCA1 mutation carriers. SNPs rs7297051, rs805510 and rs113824616 were also associated with breast cancer risk at P < 0.05 in East Asians, but none of the associations were statistically significant in African descendants. Multiple candidate functional variants are located in putative enhancer sequences. Chromatin interaction data suggested that PTHLH was the likely target gene of these enhancers. Of the six variants with the strongest evidence of potential functionality, rs11049453 was statistically significantly associated with the expression of PTHLH and its nearby gene CCDC91 at P < 0.05. CONCLUSION: This study identified four independent association signals at 12p11 and revealed potentially functional variants, providing additional insights into the underlying biological mechanism(s) for the association observed between variants at 12p11 and breast cancer risk.UK funding includes Cancer Research UK and NIH.This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s13058-016-0718-
A importância da associação obesidade e gravidez
Characteristics of the evolution of pregnancy in obese women were studied for their effect on newborn infants. Two control groups were observed - one of normal weight pregnant women, one of obese. The variables selected were: the socio-economic status of the family and the mother's age, height, arm circunference, prepregancy weight, total number of pregnancies, parity, weight gain during pregnancy, obstetric complications, birth weight, and fetal vitality. Results showed that pregnancy in obese women differs from that in normal weight women and that they show a larger incidence of obstetric complications. Children of obese mothers had a higher mortality rate principally in the perinatal period; moreover, there was also a higher rate of prematurity and a higher proportion of overweight babies among obese mothers. As a result, the distribution of the curve of the birth weight of infants of obese morthers was higher than that of infants of normal weight mothers. The conclusion reached was that whenever a pregnant obese woman reduced foot intake, with resultant insufficient weight gain, intrauterine growth was affected. Thus, it follows that pregnancy is not the best time for the obese mother to lose weight; for this reason, it is important that she receive adequate guidance in regard to diet. Obesity, therefore, is a factor contributing to high-risk pregnancy which can affect both mother and child.Foram estudados dois grupos de gestantes, sendo um de grávidas normais e outro de obesas, com a finalidade de reconhecer algumas características da evolução da gravidez, em mulheres obesas, e suas repercussões sobre o concepto. Foram relacionadas as seguintes variáveis: status sócio-econômico familiar, idade, altura, perímetro braquial, peso habitual, número de gestações anteriores, paridade materna, ganho de peso durante a gestação, idade gestacional, intercorrências durante a gestação, peso ao nascer e vitalidade do recém-nascido. Pelos resultados concluiu-se que as gestantes obesas são diferentes das normais e apresentam maior incidência de complicações obstétricas. Os recém-nascidos, filhos de obesas, registraram índice maior de mortalidade, principalmente no período perinatal. Houve maior incidência de prematuridade e de fetos macrossômicos, sendo a curva de distribuição de peso ao nascer diferente da dos recém-nascidos das gestantes normais. A média de peso ao nascer das crianças das gestantes obesas é maior que o das normais. Concluiu-se ainda que toda vez que a gestante obesa sofre restrição alimentar, com ganho de peso inadequado, o crescimento intra-uterino é afetado; não sendo, portanto, a época da gravidez a melhor para a obesa perder peso, mas, ao contrário, ela deveria receber uma orientação alimentar adequada. A obesidade é pois um fator de aumento do risco gravídico, que pode afetar tanto a mãe como o concepto
Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET
The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
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