704 research outputs found
How to make Dupire's local volatility work with jumps
There are several (mathematical) reasons why Dupire's formula fails in the
non-diffusion setting. And yet, in practice, ad-hoc preconditioning of the
option data works reasonably well. In this note we attempt to explain why. In
particular, we propose a regularization procedure of the option data so that
Dupire's local vol diffusion process recreates the correct option prices, even
in manifest presence of jumps
A Variational Method in Out of Equilibrium Physical Systems
A variational principle is further developed for out of equilibrium dynamical
systems by using the concept of maximum entropy. With this new formulation it
is obtained a set of two first-order differential equations, revealing the same
formal symplectic structure shared by classical mechanics, fluid mechanics and
thermodynamics. In particular, it is obtained an extended equation of motion
for a rotating dynamical system, from where it emerges a kind of topological
torsion current of the form , with and
denoting components of the vector potential (gravitational or/and
electromagnetic) and is the angular velocity of the accelerated frame.
In addition, it is derived a special form of Umov-Poynting's theorem for
rotating gravito-electromagnetic systems, and obtained a general condition of
equilibrium for a rotating plasma. The variational method is then applied to
clarify the working mechanism of some particular devices, such as the Bennett
pinch and vacuum arcs, to calculate the power extraction from an hurricane, and
to discuss the effect of transport angular momentum on the radiactive heating
of planetary atmospheres. This development is seen to be advantageous and opens
options for systematic improvements.Comment: 22 pages, 1 figure, submitted to review, added one referenc
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Deficiencies in the transfer and availability of clinical trials evidence: A review of existing systems and standards
Background: Decisions concerning drug safety and efficacy are generally based on pivotal evidence provided by clinical trials. Unfortunately, finding the relevant clinical trials is difficult and their results are only available in text-based reports. Systematic reviews aim to provide a comprehensive overview of the evidence in a specific area, but may not provide the data required for decision making. Methods: We review and analyze the existing information systems and standards for aggregate level clinical trials information from the perspective of systematic review and evidence-based decision making. Results: The technology currently used has major shortcomings, which cause deficiencies in the transfer, traceability and availability of clinical trials information. Specifically, data available to decision makers is insufficiently structured, and consequently the decisions cannot be properly traced back to the underlying evidence. Regulatory submission, trial publication, trial registration, and systematic review produce unstructured datasets that are insufficient for supporting evidence-based decision making. Conclusions: The current situation is a hindrance to policy decision makers as it prevents fully transparent decision making and the development of more advanced decision support systems. Addressing the identified deficiencies would enable more efficient, informed, and transparent evidence-based medical decision making
Power Packet Networks for Wave Energy Converter Arrays
One of the biggest challenges for all renewable energy sources (RES) is that they are variable power generators which will require reactive power or energy storage systems (ESS) to provide reliable power quality (ideally power factor of one) at the power grid generation side. The present invention is directed to a power packet network (PPN) for integrating wave energy converter (WEC) arrays into microgrids. Specifically, an array of WECs can be physically positioned such that the incoming regular waves will produce an output emulating an N-phase AC system such that the PPN output power is constant. ESS requirements are thereby minimized whilst maintaining grid stability with high power quality. This will enable RES integration onto a future smart grid for large-scale adoption and cost reduction while preserving high efficiency, reliability, and resiliency.https://digitalcommons.mtu.edu/patents/1160/thumbnail.jp
Age Estimation in Han Adults by Thin-Layer CT Scan of Cranial Sutures
 Objective To explore the value of degree of cranial suture closure in forensic adult age estimation by thin-layer CT scan and establish an adult age estimation model of the Han nationality. Methods Thin-layer CT scan samples of the heads of 220 healthy Sichuan Han adults (110 males, 110 females) aged 20 to 70 were collected, of which 20 samples (10 males, 10 females) were randomly selected as test samples. The sagittal suture, coronal suture (both left and right) and lambdoid suture (both left and right) were respectively and equally divided into 2 segments, and every segment was equally divided into 10 layers and the corresponding multiplanar reformation (MPR) images were selected. The closure of cranial sutures on MPR images was classified into the grades 1-7. The correlations between cranial sutures and age were analyzed to build regression equation for age estimation. Results The degree of closure of sagittal suture, coronal suture (both left and right) and lambdoid suture (both left and right) was positively correlated with age. The coefficient of determination (R2) of regression equation was 0.419 in males, 0.589 in females, and 0.522 in all samples. The results of the verification test showed that the mean absolute error (MAE) was 6.39 years in males, 6.16 years in females, and 6.29 years in all samples. Conclusion There was a higher accuracy in adult age estimation by thin-layer CT scan of cranial sutures. The age of Han nationality adults can be estimated by the degree of cranial sutures closure
TBK1: a new player in ALS linking autophagy and neuroinflammation.
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder affecting motor neurons, resulting in progressive muscle weakness and death by respiratory failure. Protein and RNA aggregates are a hallmark of ALS pathology and are thought to contribute to ALS by impairing axonal transport. Mutations in several genes known to contribute to ALS result in deposition of their protein products as aggregates; these include TARDBP, C9ORF72, and SOD1. In motor neurons, this can disrupt transport of mitochondria to areas of metabolic need, resulting in damage to cells and can elicit a neuroinflammatory response leading to further neuronal damage. Recently, eight independent human genetics studies have uncovered a link between TANK-binding kinase 1 (TBK1) mutations and ALS. TBK1 belongs to the IKK-kinase family of kinases that are involved in innate immunity signaling pathways; specifically, TBK1 is an inducer of type-1 interferons. TBK1 also has a major role in autophagy and mitophagy, chiefly the phosphorylation of autophagy adaptors. Several other ALS genes are also involved in autophagy, including p62 and OPTN. TBK1 is required for efficient cargo recruitment in autophagy; mutations in TBK1 may result in impaired autophagy and contribute to the accumulation of protein aggregates and ALS pathology. In this review, we focus on the role of TBK1 in autophagy and the contributions of this process to the pathophysiology of ALS
Systematic Review of Medicine-Related Problems in Adult Patients with Atrial Fibrillation on Direct Oral Anticoagulants
New oral anticoagulant agents continue to emerge on the market and their safety requires assessment to provide evidence of their suitability for clinical use. There-fore, we searched standard databases to summarize the English language literature on medicine-related problems (MRPs) of direct oral anticoagulants DOACs (dabigtran, rivaroxban, apixban, and edoxban) in the treatment of adults with atri-al fibrillation. Electronic databases including Medline, Embase, International Pharmaceutical Abstract (IPA), Scopus, CINAHL, the Web of Science and Cochrane were searched from 2008 through 2016 for original articles. Studies pub-lished in English reporting MRPs of DOACs in adult patients with AF were in-cluded. Seventeen studies were identified using standardized protocols, and two reviewers serially abstracted data from each article. Most articles were inconclusive on major safety end points including major bleeding. Data on major safety end points were combined with efficacy. Most studies inconsistently reported adverse drug reactions and not adverse events or medication error, and no definitions were consistent across studies. Some harmful drug effects were not assessed in studies and may have been overlooked. Little evidence is provided on MRPs of DOACs in patients with AF and, therefore, further studies are needed to establish the safety of DOACs in real-life clinical practice
Sex Characteristics and Distribution of External Ear in Uygur Population of Xinjiang
Objective To analyze the characteristics of the bilateral external ears of Uygur adults by directly observing the morphological characteristics of the external ears of Uygur adults and classifying each feature. The frequency distribution of the characteristics was calculated to provide reference for forensic identification. Methods The 210 cases (75 males and 135 females) of bilateral external ear photos of Uygur adults in Xinjiang that met the inclusion criteria were collected. The frequencies of the features of the external ear were recorded and distinguished between the two sexes and the different sides. The data were statistically analyzed by SPSS 21.0 statistical software. Results The shapes of the external ears of males and females were commonly oblique or rectangular (34.67% of the left external ear of males and 41.33% of the right were oblique; 30.37% of the left and right external ear of females were rectangular), while triangular ears were the rare variants and the least common. Sex and bilateral differences were observed as regards the form of the helix in the subjects. Normally rolled helix was the most common (58.67% males and 61.48% females for the left ear; 60.00% males and 72.59% females for the right ear). Wide covering scapha helix was the most rare for the male left ear and flat helix was the most rare for the female right ear. Square and free earlobes were the most common (49.33% males and 62.96% females for the left ear; 40.00% males and 54.81% females for the right ear), whereas triangular earlobes were rarely seen. Single knob tragus (40.00% males and 37.78% females for the left ear; 37.33% males and 33.33% females for the right ear) and projection type of Darwin’s tubercle (50.67% males and 40.00% females for the left ear; 48.00% males and 39.26% females for the right ear) were found to be common. Conclusion The characteristics of the bilateral external ears of male and female Uygur adults have differences, which can be used for forensic identification
Measurements of integrated and differential cross sections for isolated photon pair production in pp collisions at √s=8 TeV with the ATLAS detector
A measurement of the production cross section for two isolated photons in proton-proton collisions at a center-of-mass energy of √s=8 TeV is presented. The results are based on an integrated luminosity of 20.2 fb−1 recorded by the ATLAS detector at the Large Hadron Collider. The measurement considers photons with pseudorapidities satisfying |ηγ|40GeV and EγT,2>30 GeV for the two leading photons ordered in transverse energy produced in the interaction. The background due to hadronic jets and electrons is subtracted using data-driven techniques. The fiducial cross sections are corrected for detector effects and measured differentially as a function of six kinematic observables. The measured cross section integrated within the fiducial volume is 16.8 ± 0.8 pb . The data are compared to fixed-order QCD calculations at next-to-leading-order and next-to-next-to-leading-order accuracy as well as next-to-leading-order computations including resummation of initial-state gluon radiation at next-to-next-to-leading logarithm or matched to a parton shower, with relative uncertainties varying from 5% to 20%
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