"Price Barriers" and the Dynamics of Asset Prices in Equilibrium

In a variety of realistic scenarios, some investors trade infrequently rather than continuously, basing their buy or sell decisions on current price levels. A “price barrier” is a price level at which a large number of investors either buy or sell securities. We analyze the dynamics of asset prices in an economy with infrequent traders and price barriers. Our analysis predicts that when price barriers exist, both asset prices and price volatility can jump at the time the price barrier is reached, even if the trade is rationally anticipated. Moreover, the direction of the price jump may very well be the opposite of what one would expect. A price-triggered purchase may generate a downward jump in stock prices and, vice versa, a price-triggered sale may induce stock prices to jump above the price barrier. This is because trades affect prices before they are implemented: the anticipation of a stock purchase inflates stock prices, while the anticipation of a stock sale depresses stock prices. In the case of repeated trades, before-trade prices anticipate not only the next trade, but also the following ones. This may lead to the counterintuitive result that stock prices are inflated rather than depressed, in the proximity of a stock sale

"Price Barriers" and the Dynamics of Asset Prices in Equilibrium

In a variety of realistic scenarios, some investors trade infrequently rather than continuously, basing their buy or sell decisions on current price levels. A “price barrier” is a price level at which a large number of investors either buy or sell securities. We analyze the dynamics of asset prices in an economy with infrequent traders and price barriers. Our analysis predicts that when price barriers exist, both asset prices and price volatility can jump at the time the price barrier is reached, even if the trade is rationally anticipated. Moreover, the direction of the price jump may very well be the opposite of what one would expect. A price-triggered purchase may generate a downward jump in stock prices and, vice versa, a price-triggered sale may induce stock prices to jump above the price barrier. This is because trades affect prices before they are implemented: the anticipation of a stock purchase inflates stock prices, while the anticipation of a stock sale depresses stock prices. In the case of repeated trades, before-trade prices anticipate not only the next trade, but also the following ones. This may lead to the counterintuitive result that stock prices are inflated rather than depressed, in the proximity of a stock sale

Extracellular ATP-induced NO production and its dependence on membrane Ca2+ flux in Salvia miltiorrhiza hairy roots

Extracellular ATP (eATP) is a novel signalling agent, and nitric oxide (NO) is a well-established signal molecule with diverse functions in plant growth and development. This study characterizes NO production induced by exogenous ATP and examines its relationship with other important signalling agents, Ca2+ and H2O2 in Salvia miltiorrhiza hairy root culture. Exogenous ATP was applied at 10–500 μM to the hairy root cultures and stimulated NO production was detectable within 30 min. The NO level increased with ATP dose from 10–100 μM but decreased from 100–200 μM or higher. The ATP-induced NO production was mimicked by a non-hydrolysable ATP analogue ATPγS, but only weakly by ADP, AMP or adenosine. The ATP-induced NO production was blocked by Ca2+ antagonists, but not affected by a protein kinase inhibitor. ATP also induced H2O2 production, which was dependent on both Ca2+ and protein kinases, and also on NO biosynthesis. On the other hand, ATP induced a rapid increase in the intracellular Ca2+ level, which was dependent on NO but not H2O2. The results suggest that NO is implicated in ATP-induced responses and signal transduction in plant cells, and ATP signalling is closely related to Ca2+ and ROS signalling

Modeling Dispersive Coupling and Losses of Localized Optical and Mechanical Modes in Optomechanical Crystals

Periodically structured materials can sustain both optical and mechanical excitations which are tailored by the geometry. Here we analyze the properties of dispersively coupled planar photonic and phononic crystals: optomechanical crystals. In particular, the properties of co-resonant optical and mechanical cavities in quasi-1D (patterned nanobeam) and quasi-2D (patterned membrane) geometries are studied. It is shown that the mechanical Q and optomechanical coupling in these structures can vary by many orders of magnitude with modest changes in geometry. An intuitive picture is developed based upon a perturbation theory for shifting material boundaries that allows the optomechanical properties to be designed and optimized. Several designs are presented with mechanical frequency ~ 1-10 GHz, optical Q-factor Qo > 10^7, motional masses meff 100 femtograms, optomechanical coupling length LOM < 5 microns, and a radiation-limited mechanical Q-factor Qm > 10^7.Comment: 25 pages, 9 figure

Modelling of photonic wire Bragg Gratings

Some important properties of photonic wire Bragg grating structures have been investigate. The design, obtained as a generalisation of the full-width gap grating, has been modelled using 3D finite-difference time-domain simulations. Different types of stop-band have been observed. The impact of the grating geometry on the lowest order (longest wavelength) stop-band has been investigated - and has identified deeply indented configurations where reduction of the stop-bandwidth and of the reflectivity occurred. Our computational results have been substantially validated by an experimental demonstration of the fundamental stop-band of photonic wire Bragg gratings fabricated on silicon-on-insulator material. The accuracy of two distinct 2D computational models based on the effective index method has also been studied - because of their inherently much greater rapidity and consequent utility for approximate initial designs. A 2D plan-view model has been found to reproduce a large part of the essential features of the spectral response of full 3D models

Identificación de la probabilidad de presentar un evento cardiovascular a 10 años mediante la calculadora de riesgo framigham y la prevalencia de los factores de riesgo evaluados en este instrumento en la población adulto mayor valorada en consulta externa por el servicio de medicina interna del hospital San Rafael de Facatativá y del hospital san Rafael del espinal durante el primer semestre del año 2017

Objetivo: Establecer la prevalencia de factores de riesgo cardiovascular y la probabilidad de presentar un evento cardiovascular a 10 años en el adulto mayor del Hospital San Rafael de Facatativá y el Hospital San Rafael del Espinal mediante la calculadora de riesgo cardiovascular de Framingham valorada en consulta externa por el servicio de medicina interna durante el primer semestre del año 2017. Métodos: se realizó un estudio tipo analítico de corte transversal retrospectivo, en donde se tomó como población pacientes adultos mayores entre 60 y 74 años, vinculados en el Hospital San Rafael de Facatativá y el Hospital San Rafael del Espinal durante el primer semestre del año 2017. A partir de los registros de historias clínicas diligenciados en consulta externa por el servicio de medicina interna, se extrajeron variables como lo fueron edad, sexo, tabaquismo, presión arterial y aquellos que tenían diagnóstico de hipertensión arterial ya instaurado y que, a su vez, recibían tratamiento antihipertensivo. Con los datos obtenidos, a partir de la escala de Framingham se estableció el riesgo cardiovascular a 10 años con la correspondiente edad cardiovascular de cada muestra a estudio, para posteriormente realizar un análisis bivariado para asociar la prevalencia de factores de riesgo cardiovascular con la probabilidad de tener un alto riesgo cardiovascular. Resultados: La prevalencia de factores de riesgo en las dos poblaciones, se muestra que la presión arterial sistólica elevada y la hipertensión arterial son los factores de riesgo con mayor prevalencia (>70%) y se muestra que el factor de riesgo con menor prevalencia es el de ser fumador (120 mmHg) (p<0,01), tener diagnóstico de diabetes mellitus (p <0,01), hallándose una diferencia pues en el hospital San Rafael de Facatativá ,tener hipertensión arterial (p <0,05), ser fumador (p <0,01), estar sin tratamiento con antihipertensivos (p <0,01); no fue posible encontrar asociación para las variables HDL y colesterol total, para el hospital San Rafael de Espinal estar sin tratamiento con antihipertensivos (p=0,01); tener HDL bajo (p <0,05), no fue posible encontrar asociación para las variables diagnóstico de hipertensión arterial, ser fumador y colesterol total. Conclusión: El hallazgo más importante de esta investigación arrojó que existe un alto riesgo cardiovascular en las poblaciones objeto de estudio, en donde el envejecimiento de la población se evidenció con el resultado obtenido de la edad cardiovascular es mayor a la edad cronológica, adicionalmente se consiguió demostrar una alta prevalencia de factores de riesgo para desarrollar una enfermedad cardiovascular en la población de estudio.PregradoMédico(a) Cirujan

A Fourier (k-) space design approach for controllable photonic band and localization states in aperiodic lattices

In this paper we present a systematic study of photonic bandgap engineering using aperiodic lattices (ALs). Up to now ALs have tended to be defined by specific formulae (e.g. Fibonacci, Cantor), and theories have neglected other useful ALs along with the vast majority of non-useful (random) ALs. Here, we present a practical and efficient Fourier space-based general theory to identify all those ALs having useful band properties, which are characterized by well-defined Fourier (i.e. lattice momentum) components. Direct control of field localization comes via control of the Parseval strength competition between the different Fourier components characterizing a lattice. Real-space optimization of ALs tends to be computationally demanding. However, via our Fourier space-based simulated annealing inverse optimization algorithm, we efficiently tailor the relative strength of the AL Fourier components for precise control of photonic band and localization properties.Comment: 25 pages, 4 figure

FourFold Asthma Study (FAST): a study protocol for a randomised controlled trial evaluating the clinical cost-effectiveness of temporarily quadrupling the dose of inhaled steroid to prevent asthma exacerbations

BACKGROUND: Asthma is one of the commonest chronic diseases in the UK. Acute exacerbations of asthma are unpredictable, disruptive and frightening. They cause considerable morbidity and account for a large component of the health service costs of asthma. The widespread use of an asthma self-management plan, designed to encourage disease monitoring and timely intervention, can reduce exacerbations and is, therefore, recommended for all patients with asthma. Unfortunately, the majority of patients are not provided with such a plan. There are a variety of reasons for this but uncertainty about what to include in the plan when asthma control is deteriorating, but before the need for orally administered corticosteroids, is a contributing factor. The aim of this trial is to determine whether an asthma self-management plan, which includes a temporary quadrupling of the dose of inhaled corticosteroid when asthma control starts to deteriorate, reduces asthma exacerbations requiring orally administered corticosteroids or unscheduled health care consultation for asthma. METHODS: A multicentre, pragmatic, randomised trial in adults aged over 16 years with a clinical diagnosis of asthma, treated with a licensed dose of inhaled corticosteroid and at least one exacerbation in the previous 12 months requiring treatment with systemic corticosteroids. Participants will be randomised to either a self-management plan, which includes a temporary (maximum of 14 days) fourfold increase in inhaled corticosteroid or the same plan without an increase in inhaled corticosteroid. Participants will be followed up at 6 and 12 months and will attend the clinic for an additional visit if their asthma control deteriorates. The primary outcome is time to first asthma exacerbation, defined as the need for systemic corticosteroids and/or unscheduled health care consultation for asthma. The estimated sample size is 1800 participants. DISCUSSION: The FAST trial is an independent study that has been prioritised and commissioned by the National Institute for Health Research (NIHR) in the United Kingdom. It will provide high-quality evidence to inform clinical decision-making on the role of an asthma self-management plan, which includes a temporary fourfold increase of inhaled corticosteroid, when asthma control starts to deteriorate. The first participant was randomised on 17th May 2013 and recruitment will close on 31 January 2016 with the last patient last visit taking place in January 2017. TRIAL REGISTRATION: ISRCTN: 15441965, registered on 25 April 2013

Budesonide/formoterol and formoterol provide similar rapid relief in patients with acute asthma showing refractoriness to salbutamol

BACKGROUND: To compare the efficacy and safety of budesonide/formoterol (Symbicort(®)) with formoterol (Oxis(®)) in the treatment of patients with acute asthma who showed evidence of refractoriness to short-acting β(2)-agonist therapy. METHODS: In a 3 hour, randomized, double-blind study, a total of 115 patients with acute asthma (mean FEV(1 )40% of predicted normal) and a refractory response to salbutamol (mean reversibility 2% of predicted normal after inhalation of 400 μg), were randomized to receive either budesonide/formoterol (320/9 μg, 2 inhalations at t = -5 minutes and 2 inhalations at 0 minutes [total dose 1280/36 μg]) or formoterol (9 μg, 2 inhalations at t = -5 minutes and 2 inhalations at 0 minutes [total dose 36 μg]). The primary efficacy variable was the average FEV(1 )from the first intake of study medication to the measurement at 90 minutes. Secondary endpoints included changes in FEV(1 )at other timepoints and change in respiratory rate at 180 minutes. Treatment success, treatment failure and patient assessment of the effectiveness of the study medication were also measured. RESULTS: FEV(1 )increased after administration of the study medication in both treatment groups. No statistically significant difference between the treatment groups was apparent for the primary outcome variable, or for any of the other efficacy endpoints. There were no statistically significant between-group differences for treatment success, treatment failure or patient assessment of medication effectiveness. Both treatments were well tolerated. CONCLUSION: Budesonide/formoterol and formoterol provided similarly rapid relief of acute bronchoconstriction in patients with asthma who showed evidence of refractoriness to a short-acting β(2)-agonist

Broadband Reconfiguration of OptoMechanical Filters

We demonstrate broad-band reconfiguration of coupled photonic crystal nanobeam cavities by using optical gradient force induced mechanical actuation. Propagating waveguide modes that exist over wide wavelength range are used to actuate the structures and in that way control the resonance of localized cavity mode. Using this all-optical approach, more than 18 linewidths of tuning range is demonstrated. Using on-chip temperature self-referencing method that we developed, we determined that 20 % of the total tuning was due to optomechanical reconfiguration and the rest due to thermo-optic effects. Independent control of mechanical and optical resonances of our structures, by means of optical stiffening, is also demonstrated