1,101 research outputs found

    Pricing and hedging of Asian options: Quasi-explicit solutions via Malliavin calculus

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    We use Malliavin calculus and the Clark-Ocone formula to derive the hedging strategy of an arithmetic Asian Call option in general terms. Furthermore we derive an expression for the density of the integral over time of a geometric Brownian motion, which allows us to express hedging strategy and price of the Asian option as an analytic expression. Numerical computations which are based on this expression are provided

    Development and simulation of multi-diagnostic Bayesian analysis for 2D inference of divertor plasma characteristics

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    We present results of the design, implementation and testing of a Bayesian multi-diagnostic inference system which combines various divertor diagnostics to infer the 2D fields of electron temperature T e, density n e and deuterium neutral density n 0 in the divertor. The system was tested using synthetic diagnostic measurements derived from SOLPS-ITER fluid code predictions of the MAST-U Super-X divertor which include appropriate added noise. Two SOLPS-ITER simulations in different states of detachment, taken from a scan of the nitrogen seeding rate, were used as test-cases. Taken across both test-cases, the median absolute fractional errors in the inferred electron temperature and density estimates were 10.3% and 10.1% respectively. Differences between the inferred fields and the test-cases were well explained by solution uncertainty estimates derived from posterior sampling. This work represents a step toward a larger goal of obtaining a quantitative, 2D description of the divertor plasma state directly from experimental data, which could be used to gain better understanding of divertor physics phenomena

    The Limits of Anthropocene Narratives

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    The rapidly growing transdisciplinary enthusiasm about developing new kinds of Anthropocene stories is based on the shared assumption that the Anthropocene predicament is best made sense of by narrative means. Against this assumption, this article argues that the challenge we are facing today does not merely lie in telling either scientific, socio-political, or entangled Anthropocene narratives to come to terms with our current condition. Instead, the challenge lies in coming to grips with how the stories we can tell in the Anthropocene relate to the radical novelty of the Anthropocene condition about which no stories can be told. What we need to find are meaningful ways to reconcile an inherited commitment to narrativization and the collapse of storytelling as a vehicle of understanding the Anthropocene as our current predicament

    Importance of the Active Site "Canopy" Residues in an O_2-Tolerant [NiFe]-Hydrogenase

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    The active site of Hyd-1, an oxygen-tolerant membrane-bound [NiFe]-hydrogenase from Escherichia coli, contains four highly conserved residues that form a “canopy” above the bimetallic center, closest to the site at which exogenous agents CO and O_2 interact, substrate H_2 binds, and a hydrido intermediate is stabilized. Genetic modification of the Hyd-1 canopy has allowed the first systematic and detailed kinetic and structural investigation of the influence of the immediate outer coordination shell on H_2 activation. The central canopy residue, arginine 509, suspends a guanidine/guanidinium side chain at close range above the open coordination site lying between the Ni and Fe atoms (N–metal distance of 4.4 Å): its replacement with lysine lowers the H_2 oxidation rate by nearly 2 orders of magnitude and markedly decreases the H_2/D_2 kinetic isotope effect. Importantly, this collapse in rate constant can now be ascribed to a very unfavorable activation entropy (easily overriding the more favorable activation enthalpy of the R509K variant). The second most important canopy residue for H_2 oxidation is aspartate 118, which forms a salt bridge to the arginine 509 headgroup: its mutation to alanine greatly decreases the H_2 oxidation efficiency, observed as a 10-fold increase in the potential-dependent Michaelis constant. Mutations of aspartate 574 (also salt-bridged to R509) to asparagine and proline 508 to alanine have much smaller effects on kinetic properties. None of the mutations significantly increase sensitivity to CO, but neutralizing the expected negative charges from D118 and D574 decreases O_2 tolerance by stabilizing the oxidized resting Ni^(III)–OH state (“Ni-B”). An extensive model of the catalytic importance of residues close to the active site now emerges, whereby a conserved gas channel culminates in the arginine headgroup suspended above the Ni and Fe

    Long non-coding RNA-derived peptides are immunogenic and drive a potent anti-tumour response

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    Protein arginine methyltransferase (PRMT) 5 is over-expressed in a variety of cancers and the master transcription regulator E2F1 is an important methylation target. We have explored the role of PRMT5 and E2F1 in regulating the non-coding genome and report here a striking effect on long non-coding (lnc) RNA gene expression. Moreover, many MHC class I protein-associated peptides were derived from small open reading frames in the lncRNA genes. Pharmacological inhibition of PRMT5 or adjusting E2F1 levels qualitatively altered the repertoire of lncRNA-derived peptide antigens displayed by tumour cells. When presented to the immune system as either ex vivo-loaded dendritic cells or expressed from a viral vector, lncRNA-derived peptides drove a potent antigen-specific CD8 T lymphocyte response, which translated into a significant delay in tumour growth. Thus, lncRNA genes encode immunogenic peptides that can be deployed as a cancer vaccine

    Pathologic RFC1 repeat expansions do not contribute to the development of inflammatory neuropathies

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    Biallelic expansions of the AAGGG repeat in the replication factor C subunit 1 (RFC1) have recently been described to be responsible for cerebellar ataxia, peripheral neuropathy and vestibular areflexia syndrome. This genetic alteration has also allowed genetic classification in up to one-third of cases with idiopathic sensory neuropathy. Here, we screened a well-characterized cohort of inflammatory neuropathy patients for RFC1 repeat expansions to explore whether RFC1 was increased from background rates and possibly involved in the pathogenesis of inflammatory neuropathy. A total of 259 individuals with inflammatory neuropathy and 243 healthy controls were screened for the AAGGG repeat expansion using short-range flanking PCR and repeat-primed PCR. Cases without amplifiable PCR product on flanking PCR and positive repeat-primed PCR were also tested for the mostly non-pathogenic expansions of the AAAGG and AAAAG repeat units. None of the patients showed biallelic AAGGG expansion of RFC1, and their carrier frequency for AAGGG was comparable with controls [n = 27 (5.2%) and n = 23 (4.7%), respectively; P > 0.5]. Data suggest that the pathologic expansions of AAGGG repeats do not contribute to the development of inflammatory neuropathies nor lead to misdiagnosed cases. Accordingly, routine genetic screening for RFC1 repeat expansion is not indicated in this patient population

    How many people will need palliative care in Scotland by 2040? A mixed-method study of projected palliative care need and recommendations for service delivery.

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    OBJECTIVE: To estimate future palliative care need and complexity of need in Scotland, and to identify priorities for future service delivery. DESIGN: We estimated the prevalence of palliative care need by analysing the proportion of deaths from defined chronic progressive illnesses. We described linear projections up to 2040 using national death registry data and official mortality forecasts. An expert consultation and subsequent online consensus survey generated recommendations on meeting future palliative care need. SETTING: Scotland, population of 5.4 million. PARTICIPANTS: All decedents in Scotland over 11 years (2007 to 2017). The consultation had 34 participants; 24 completed the consensus survey. PRIMARY AND SECONDARY OUTCOMES: Estimates of past and future palliative care need in Scotland from 2007 up to 2040. Multimorbidity was operationalised as two or more registered causes of death from different disease groups (cancer, organ failure, dementia, other). Consultation and survey data were analysed descriptively. RESULTS: We project that by 2040, the number of people requiring palliative care will increase by at least 14%; and by 20% if we factor in multimorbidity. The number of people dying from multiple diseases associated with different disease groups is projected to increase from 27% of all deaths in 2017 to 43% by 2040. To address increased need and complexity, experts prioritised sustained investment in a national digital platform, roll-out of integrated electronic health and social care records; and approaches that remain person-centred. CONCLUSIONS: By 2040 more people in Scotland are projected to die with palliative care needs, and the complexity of need will increase markedly. Service delivery models must adapt to serve growing demand and complexity associated with dying from multiple diseases from different disease groups. We need sustained investment in secure, accessible, integrated and person-centred health and social care digital systems, to improve care coordination and optimise palliative care for people across care settings.Marie Curie small gran

    Superfield T-duality rules

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    A geometric treatment of T-duality as an operation which acts on differential forms in superspace allows us to derive the complete set of T-duality transformation rules which relate the superfield potentials of D=10 type IIA supergravity with those of type IIB supergravity including Ramond-Ramond superfield potentials and fermionic supervielbeins. We show that these rules are consistent with the superspace supergravity constraints.Comment: 24 pages, latex, no figures. V2 misprints corrected. V3. One reference ([30]) and a comment on it ('Notice added') on p. 19 adde

    Role of Surface Energy and Nano-Roughness in the Removal Efficiency of Bacterial Contamination by Nonwoven Wipes from Frequently Touched Surfaces

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    Healthcare associated infections (HCAIs) are responsible for substantial patient morbidity, mortality and economic cost. Infection control strategies for reducing rates of transmission include the use of nonwoven wipes to remove pathogenic bacteria from frequently touched surfaces. Wiping is a dynamic process that involves physicochemical mechanisms to detach and transfer bacteria to fibre surfaces within the wipe. The purpose of this study was to determine the extent to which systematic changes in fibre surface energy and nano-roughness influence removal of bacteria from an abiotic polymer surface in dry wiping conditions, without liquid detergents or disinfectants. Nonwoven wipe substrates composed of two commonly used fibre types, lyocell (cellulosic) and polypropylene, with different surface energies and nano-roughnesses, were manufactured using pilot-scale nonwoven facilities to produce samples of comparable structure and dimensional properties. The surface energy and nano-roughness of some lyocell substrates were further adjusted by either oxygen (O2) or hexafluoroethane (C2F6) gas plasma treatment. Static adpression wiping of an inoculated surface under dry conditions produced removal efficiencies of between 9.4% and 15.7%, with no significant difference (p < 0.05) in the relative removal efficiencies of Escherichia coli, Staphylococcus aureus or Enterococcus faecalis. However, dynamic wiping markedly increased peak wiping efficiencies to over 50%, with a minimum increase in removal efficiency of 12.5% and a maximum increase in removal efficiency of 37.9% (all significant at p < 0.05) compared with static wiping, depending on fibre type and bacterium. In dry, dynamic wiping conditions, nonwoven wipe substrates with a surface energy closest to that of the contaminated surface produced the highest E. coli removal efficiency, while the associated increase in fibre nano-roughness abrogated this trend with S. aureus and E. faecalis. Plasma modification of the nano-roughness and surface energy of fibres in nonwoven wipes was found to influence the relative removal efficiencies of common bacterial pathogens from model healthcare surfaces under dynamic wiping conditions
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