On Expectations-Driven Business Cycles in Economies with Production Externalities: A Comment

Eusepi (2009, International Journal of Economic Theory 5, pp. 9-23) analytically finds that a one-sector real business cycle model may exhibit positive co-movement between consumption and investment when the equilibrium wage-hours locus is positively-sloped and steeper than the household's labor supply curve. However, we show that this condition does not imply expectations-driven business cycles will emerge in Eusepi's model. Specifically, a positive news shock about future productivity improvement leads to an aggregate recession whereby output, employment, consumption and investment all fall in the announcement period.Expectations-Driven Business Cycles; Production Externalities.

Coherent amplitudon generation in K_0.3MoO_3 through ultrafast inter-band quasi particle decay

The charge density wave system K_0.3MoO_3 has been studied using variable energy pump-probe spectroscopy, ellipsometry, and inelastic light scattering. The observed transient reflectivity response exhibits quite a complex behavior, containing contributions due to quasi particle excitations, coherent amplitudons and phonons, and heating effects. The generation of coherent amplitudons is discussed in terms of relaxation of photo-excited quasi particles, and is found to be resonant with the interband plasmon frequency. Two additional coherent excitations observed in the transients are assigned to zone-folding modes of the charge density wave state

STUDIES ON THE NUTRIENT CONTENT OF SPECIES Mytilus galloprovincialis OF THE BLACK SEA

It is well known that, among the marine organisms, mollusks are highly appreciated in many European, Asian and North American countries. In the Romanian area of the Black Sea, mussel Mytilus galloprovincialis can be found in deep areas which form a belt around the sea on the continental platform. There are significant variations of the main environmental factors which directly influence the physiological behavior of the organisms and the accumulation of the biochemical components with nutritional value. This paper correlates the study of the dynamics of the main biochemical compounds with the environmental factors and the annual ontogenetic phases of the organisms. There are also presented comparative studies concerning the rock mollusks and mollusks of deep from the Black Sea. It was found variations in quantitative results for biochemical composition. Cases are due to seasonal variations of physical-chemical conditions of seawater

Exoplanet Terra Incognita

Exoplanet surface imaging, cartography and the search for exolife are the next frontiers of planetology and astrophysics. Here we present an over-view of ideas and techniques to resolve albedo features on exoplanetary surfaces. Albedo maps obtained in various spectral bands (similar to true-colour images) may reveal exoplanet terrains, geological history, life colonies, and even artificial structures of advanced civilizations.Comment: 16 pages, 6 figures, Planetary Cartograph

ADS-B Crowd-Sensor Network and Two-Step Kalman Filter for GNSS and ADS-B Cyber-Attack Detection

Automatic Dependent Surveillance-Broadcast is an Air Traffic Control system in which aircraft transmit their own information (identity, position, velocity, etc.) to ground sensors for surveillance purposes. This system has many advantages compared to the classical surveillance radars: easy and low-cost implementation, high accuracy of data, and low renewal time, but also limitations: dependency on the Global Navigation Satellite System, a simple unencrypted and unauthenticated protocol. For these reasons, the system is exposed to attacks like jamming/spoofing of the on-board GNSS receiver or false ADS-B messages' injection. After a mathematical model derivation of different types of attacks, we propose the use of a crowd sensor network capable of estimating the Time Difference Of Arrival of the ADS-B messages together with a two-step Kalman filter to detect these attacks (on-board GNSS/ADS-B tampering, false ADS-B message injection, GNSS Spoofing/Jamming). Tests with real data and simulations showed that the algorithm can detect all these attacks with a very high probability of detection and low probability of false alarm

Fully Autonomous Orbit Determination and Synchronization for Satellite Navigation and Communication Systems in Halo Orbits

This paper presents a solution for autonomous orbit determination and time synchronization of spacecraft in Halo orbits around Lagrange points using inter-satellite links. Lagrange points are stable positions in the gravitational field of two large bodies that allow for a sustained presence of a spacecraft in a specific region. However, a challenge in operating at these points is the lack of fixed landmarks for orbit determination. The proposed solution involves using inter-satellite links to perform range and range-rate measurements, allowing for accurate computation of the spacecraft's orbit parameters without the need for any facilities on Earth. Simulations using a fleet of three satellites in Near Rectilinear Halo Orbits around the Earth-Moon Lagrange point, proposed for the Lunar Gateway stations, were conducted to demonstrate the feasibility of the approach. The results show that inter-satellite links can provide reliable and accurate solutions for orbit determination with a DRMS error lower than one meter (90th percentile) and synchronization errors of around one nanosecond. This solution paves the way for a fully autonomous fleet of spacecraft that can be used for observation, telecommunication, and navigation missions