Non-Extensive Statistical Analysis of Acoustic Emissions: The Variability of Entropic Index q during Loading of Brittle Materials until Fracture

Non-extensive statistical mechanics (NESM), introduced by Tsallis based on the principle of non-additive entropy, is a generalisation of the Boltzmann–Gibbs statistics. NESM has been shown to provide the necessary theoretical and analytical implementation for studying complex systems such as the fracture mechanisms and crack evolution processes that occur in mechanically loaded specimens of brittle materials. In the current work, acoustic emission (AE) data recorded when marble and cement mortar specimens were subjected to three distinct loading protocols until fracture, are discussed in the context of NESM. The NESM analysis showed that the cumulative distribution functions of the AE interevent times (i.e., the time interval between successive AE hits) follow a q-exponential function. For each examined specimen, the corresponding Tsallis entropic q-indices and the parameters βq and τq were calculated. The entropic index q shows a systematic behaviour strongly related to the various stages of the implemented loading protocols for all the examined specimens. Results seem to support the idea of using the entropic index q as a potential pre-failure indicator for the impending catastrophic fracture of the mechanically loaded specimens.

A Deep Learning Pipeline for Unified Modelling of Time-Correlated Noise in Exoplanets Observations

<p>The precise derivation of transit depths from stellar light curves is a key component in the construction of exoplanet transit spectra, and thereby for the characterization of exoplanet atmospheres. However, it is still deeply affected by various kinds of complex systematic errors and noises taking their source from host stars’ or instruments’ variability. On the other hand, as the volume of exoplanetary data is quickly increasing, a new way is being opened up for using machine learning as part of the data processing pipeline. By training a recurrent neural network to model the temporal dependencies in stellar light curves, our results on both real on simulated light curves highlight that it is possible to:</p> <ul> <li>Model accurately the compound of trends and periodic effects with few or no assumptions about the instrument, star, or planetary signals</li> <li>Improve the understanding of each instrument’s systematic behaviour</li> <li>Optimise a deep detrending model jointly with a transit fit</li> <li>Leverage the cross-light curves and cross-instruments information</li> </ul> <p>Such an approach therefore paves the way for a global, flexible and efficient noise-correction pipeline which will be of paramount importance to make the most of exoplanets observations and provide high precision spectra to subsequent atmospheric retrieval pipelines.</p>

The Pre-Eminence of the General Principle of Equality over Specific Prohibition of Discrimination on Suspect Grounds in Czechia

This chapter shows that the general principle of equality is the pre-eminent doctrine in Czechia. It is more often and more readily applied than ground-related anti-discrimination law by courts and administrative bodies alike, and the two doctrines are often conflated. This is paradoxical, because ground-related anti-discrimination law is distinctive and arguably addresses a graver wrong: while the general principle of equality targets random arbitrariness, irrationality or unfairness, the prohibition of discrimination on specific grounds focuses on oft-repeated, systematic behaviour and practices which track deep historical and/or current disadvantages.

Time variations of H2O and SiO masers in the proto-Planetary Nebula OH 231.8+4.2

H2O (22 GHz) and SiO masers (43, 86, 129 GHz) in the bipolar proto-planetary nebula OH 231.8+4.2 were simultaneously monitored using the 21-m antennas of the Korean VLBI Network in 2009–2015. Both species exhibit periodic flux variations that correlate with the central star’s optical light curve, with a phase delay of up to 0.15 for the maser flux variations with respect to the optical light curve. The flux densities of SiO v = 2, J = 1→0 and H2O masers decrease with time, implying that they may disappear in 10–20 years. However, there seems to have been a transient episode of intense H2O maser emission around 2010. We also found a systematic behaviour in the velocity profiles of these masers. The velocities of the H2O maser components appear to be remarkably constant, suggesting ballistic motion for the bipolar outflow in this nebula. On the other hand, those of the SiO maser clumps show a systematic radial acceleration of the individual clumps, converging to the outflow velocity of the H2O maser clumps. Measuring the full widths at zero power of the detected lines, we estimated the expansion velocities of the compact bipolar outflow traced by H2O maser and SiO thermal line, and discussed the possibility of the expanding SiO maser region in the equatorial direction. All of our analyses support that the central host star of OH231.8 is close to the tip of the AGB phase, and that the mass-loss rate recently started to decrease because of incipient post-AGB evolution.

Systematic behaviour of electron redistribution on formation of halogen-bonded complexes B⋯XY, as determined via XY halogen nuclear quadrupole coupling constants

Systematic behaviour of the fractional electron redistribution δi from B to Br with ionisation energy IB on formation of B⋯BrY.

STRATEGIC BUSINESS DEVELOPMENT AND CLIENT PROSPECTING IN THE THIRD-PARTY APARTMENT MANAGEMENT INDUSTRY

Intensifying competition and increasing market demands are forcing many third-party apartment management firms to re-evaluate their approach to business development and client prospecting. In some instances, these companies are becoming more selective about both the assignments they take on and the property owners with whom they work. Careful consideration is frequently given to a number of factors to determine if new business opportunities are a good strategic fit. This paper examines how sophisticated fee management firms make such determinations by examining the perspectives of executives representing 25 of the largest multifamily operators in the United States. The results indicate heavy reliance on relational approaches to business development, limited long-range planning, and informal channels of communication often encourage fee managers to pursue new business in an ad hoc manner despite market conditions favouring more systematic behaviour. A series of best practices are put forth to address these concerns.

Assessing the uncertainty of soil-moisture impact on convective precipitation by an ensemble approach

Soil moisture influences the occurrence of convective precipitation. Therefore an accurate knowledge of soil moisture might be useful for an improved prediction of convective cells. But still the model uncertainty overshadows the impact of soil moisture in realistic cases even in 1 km resolution and therefore convection resolving models. Only drastic soil moisture changes can exhibit the model uncertainties but the systematic behaviour is still complex and depends strongly on the strength of soil moisture change. Here we performed seven experiments with modified soil moisture using an ensemble approach for each experiment. Only a 50 % soil moisture enhancement and a complete dried soil impact precipitation patterns considerably in structure, amplitude and location in certain analysis areas. Both, the enhanced and reduced soil moisture result in a reduced precipitation rate. Replacing the soil moisture by a realistic field from different days influences the precipitation insignificantly. We point out the need for uncertainty estimations in soil moisture studies.

Insights into movement behaviour of snapper (Chrysophrys auratus, Sparidae) from a large acoustic array

Snapper is a significant fishery species in Australasia whose movement behaviour remains poorly understood. This was addressed in the present study at the within-region scale using acoustic telemetry in the Gulf St Vincent, South Australia. Over 3 years from May 2011, 54 snapper were monitored throughout ~160km2 using 41 acoustic receivers. The dispersion of >500000 detections varied in space and time, reflecting three types of space use, dependent on different types of movement behaviour. One station, near a large shipwreck, accounted for 67.8% of all detections, particularly during winter, when fish were sedentary and site attached. In spring, the fish dispersed throughout the study area to different habitats and, through summer, occupied different larger restricted areas than used in winter. Snapper were highly mobile and demonstrated systematic behaviour at several temporal scales. They moved linear distances of up to ~100km and could achieve tens of kilometres in a day in episodic movements. Through the year, their activity was distributed across areas of hundreds of square kilometres. The regional spatial management regimen was assessed against this enhanced understanding of movement behaviour. A new marine park sanctuary zone that encompassed the shipwreck was appropriately located, but possible benefits of a nearby spatial spawning closure area appear limited.