The biharmonic homotopy problem for unit vector fields on 2-tori

The bienergy of smooth maps between Riemannian manifolds, when restricted to unit vector fields, yields two different variational problems depending on whether one takes the full functional or just the vertical contribution. Their critical points, called biharmonic unit vector fields and biharmonic unit sections, form different sets. Working with surfaces, we first obtain general characterizations of biharmonic unit vector fields and biharmonic unit sections under conformal change of the metric. In the case of a 2-dimensional torus, this leads to a proof that biharmonic unit sections are always harmonic and a general existence theorem, in each homotopy class, for biharmonic unit vector fields

Does the weather affect stock market volatility?

This paper investigates the empirical association between stock market volatility and investor mood-proxies related to the weather (cloudiness, temperature and precipitation) and the environment (nighttime length). Overall, our results suggest that cloudiness and length of nighttime are inversely related to historical, implied and realized measures of volatility. The strength of association seems to vary with the location of an exchange on Earth with respect to the equator. Weather deviations from seasonal norms and dummies representing extreme weather conditions do not offer additional explanatory power in our datasets.Stock market anomalies; Volatility; Sunshine effect; SAD effect; Behavioral Finance

Two-electron processes in multiple ionization under strong soft-x-ray radiation

In a combined experimental and theoretical study we have investigated the ionization of atomic argon upon irradiation with intense soft-x-ray pulses of 105 eV photon energy from the free-electron laser FLASH. The measured ion yields show charge states up to Ar7+. The comparison with the theoretical study of the underlying photoionization dynamics highlights the importance of excited states in general and of processes governed by electron correlation in particular, namely, ionization with excitation and shake-off, processes usually inaccessible by measurements of ionic yields only. The Ar7+ yield shows a clear deviation from the predictions of the commonly used model of sequential ionization via single-electron processes and the observed signal can only be explained by taking into account the full multiplet structure of the involved configurations and by inclusion of two-electron processes. The competing process of two-photon ionization from the ground state of Ar6+ is calculated to be orders of magnitude smaller

Linear Stability of Equilibrium Points in the Generalized Photogravitational Chermnykh's Problem

The equilibrium points and their linear stability has been discussed in the generalized photogravitational Chermnykh's problem. The bigger primary is being considered as a source of radiation and small primary as an oblate spheroid. The effect of radiation pressure has been discussed numerically. The collinear points are linearly unstable and triangular points are stable in the sense of Lyapunov stability provided $\mu< \mu_{Routh}=0.0385201$. The effect of gravitational potential from the belt is also examined. The mathematical properties of this system are different from the classical restricted three body problem

Nonlinear Stability in the Generalised Photogravitational Restricted Three Body Problem with Poynting-Robertson Drag

The Nonlinear stability of triangular equilibrium points has been discussed in the generalised photogravitational restricted three body problem with Poynting-Robertson drag. The problem is generalised in the sense that smaller primary is supposed to be an oblate spheroid. The bigger primary is considered as radiating. We have performed first and second order normalization of the Hamiltonian of the problem. We have applied KAM theorem to examine the condition of non-linear stability. We have found three critical mass ratios. Finally we conclude that triangular points are stable in the nonlinear sense except three critical mass ratios at which KAM theorem fails.Comment: Including Poynting-Robertson Drag the triangular equilibrium points are stable in the nonlinear sense except three critical mass ratios at which KAM theorem fail

Electricity futures prices in an emissions constrained economy: Evidence from European power markets

We investigate the economic factors that drive electricity risk premia in the European emissions constrained economy. Our analysis is undertaken for monthly baseload electricity futures for delivery in the Nordic, French and British power markets. We find that electricity risk premia are significantly related to the volatility of electricity spot prices, demand and revenues, and the price volatility of the carbon dioxide (CO2) futures traded under the EU Emissions Trading Scheme (EU ETS). This finding has significant implications for the pricing of electricity futures since it highlights for the first time the role of carbon market uncertainties as a main determinant of the relationship between spot and futures electricity prices in Europe. Our results also suggest that for the electricity markets under scrutiny futures prices are determined rationally by risk-averse economic agents

Determinants of diagnostic and pseudodiagnostic information selection

Η ΠΕΡΙΛΗΨΗ ΒΡΙΣΚΕΤΑΙ ΜΕΣΑ ΣΤΟ ΑΡΧΕΙΟ PDFPseudodiagnosticity refers to the tendency to select impoverished information in preference to equally available diagnostic data. Mynatt, Doherty, and Dragan (1993) reported that pseudodiagnostic reasoning was attenuated in problems in which the information selection had consequences for the reasoner’s future actions in contrast to problemsin which it did not. Girotto, Evans and Legrenzi (1996) denied that such “action” problems fostered better information selection because they argued that in Mynatt’s et al.’s study action and non-action or inferencevaried in how the decision task was framed. It was predicted that for action problems there will be a higher frequency in informative data selection vs. both inference problems. In addition to that, a primacy effect for inference problems would occur irrespective of sequence of data presentation but not for action problems. We re-examined the way people reasoned about action problems and inference problems taking into consideration Girotto et al.’s criticisms. We found that even when the presentation and salience of the information was equated in both kinds of problems, diagnostic information selection was more likely foraction that for inference problems

Printed temperature sensor based on PEDOT: PSS-graphene oxide composite

Temperature sensing is an important parameter needed to be measured by the eSkin during the physical interaction of robots with real-world objects. Yet, most of the work on sensors in eSkin has focused on pressure sensing. Here we present a skin conformable printed temperature sensor with poly(3,4-ethylenedioxythiophene): poly (styr-enesulfonate) (PEDOT:PSS)-graphene oxide (GO) as a temperature sensitive layer and silver (Ag) as contact electrodes. The demonstration of PEDOT:PSS/GO as a highly temperature sensitive layer is the distinct feature of the work. The response of presented sensor observed over ~25 °C (room temperature (RT)) to 100°C, by measuring the variation in resistance across the GO/PEDOT:PSS layer showed ~80% decrease in resistance. The sensitivity of the sensor was found to be 1.09% per °C. The sensor's response was also observed under static and dynamic bending (for 1000 cycles) conditions. The stable and repeatable response of sensor, in both cases, signifies strong adhesion of the layers with negligible delamination or debonding. In comparison to the commercial thermistor, the printed GO/PEDOT:PSS sensor is faster (~73% superior) with response and recovery times of 18 s and 32 s respectively. Finally, the sensor was attached to a robotic hand to allow the robot to act by using temperature feedback