Since 2011, after the discovery of new ceramic two-dimensional materials called MXenes, the attention has been focused on their unique properties and various applications, from energy storage to nanomedicine. We present a brief perspective article of the properties of MXenes, alongside the most recent studies regarding their applications on energy, environment, wireless communications, and biotechnology. Future needs regarding the current knowledge about MXenes are also discussed in order to fully understand their nature and overcome the challenges that have restricted their use.

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The Receiver Operating Characteristics (ROC) is used for the evaluation of prediction methods in various disciplines like meteorology, geophysics, complex system physics, medicine etc. The estimation of the significance of a binary prediction method, however, remains a cumbersome task and is usually done by repeating the calculations by Monte Carlo. The FORTRAN code provided here simplifies this problem by evaluating the significance of binary predictions for a family of ellipses which are based on confidence ellipses and cover the whole ROC space.Keywords: Receiver Operating Characteristics (ROC), complex systems, systems obeying power laws, significance level, p-value Solution method: Using the statistics of random binary predictions for a given value of the predictor threshold ϵ t , one can construct the corresponding confidence ellipses. The envelope of these corresponding confidence ellipses is estimated when ϵ t varies from 0 to 1. This way a new family of ellipses is obtained, named kellipses, which covers the whole ROC plane and leads to a well defined Area Under the Curve (AUC). For the latter quantity, Mason and Graham [1] has shown that it follows the Mann-Whitney U-statistics[2] which can be applied [3] for the estimation of the statistical significance of each k-ellipse. As the transformation is invertible, any point on the ROC plane corresponds to a unique value of k, thus to a unique p-value to obtain this point by chance. The present FORTRAN code provides this p-value field on the ROC plane as well as the k-ellipses corresponding to the (p=)10%, 5% and 1% significance levels using as input the number of the positive (P) and negative (Q) cases to be predicted. PROGRAM SUMMARY Restrictions:Unusual features: In some machines, the compiler directive -O2 or -O3 should be used to avoid NaN's in some points of the p-field along the diagonal Additional comments:Running time: Depending on the application, e.g., 4s for an Intel(R) Core(TM)2 CPU E7600 at 3.06GHz with 2GB RAM for the examples presented here[1] S.

-The entropy S in natural time as well as the entropy in natural time under time reversal S− have already found useful applications in the physics of complex systems, e.g., in the analysis of electrocardiograms (ECGs). Here, we focus on the complexity measures Λ l which result upon considering how the statistics of the time series ∆S [≡ S − S−] changes upon varying the scale l. These scale specific measures are ratios of the standard deviations σ(∆S l ) and hence independent of the mean value and the standard deviation of the data. They focus on the different dynamics that appear on different scales. For this reason, they can be considered complementary to other standard measures of heart rate variability in ECG, like SDNN, as well as other complexity measures already defined in natural time. An application to the analysis of ECG -when solely using NN intervals-is presented: We show how Λ l can be used to separate ECG of healthy individuals from those suffering from congestive heart failure and sudden cardiac death.Introduction. -Natural time analysis [1][2][3] focuses in the sequential order of events occurring in a complex system. It extracts the maximum information possible from a given time series [4]. If we consider a series of N events in a complex system, the natural time attributed to the k-th event is given by χ k = k/N . For example, as shown in fig.1, in the case of an electrocardiogram (ECG) as events we may consider the heartbeats. In natural time analysis, χ k is complemented by a quantity Q k which is proportional to the energy emitted during the k-th event. Further analysis is made by studying the pair (χ k , Q k ) and introducing the normalized energy. . N ) sum up to unity, they can be considered as probabilities corresponding to χ k . The entropy S in natural time is defined [1,5,6] by S = ⟨χ ln χ⟩ − ⟨χ⟩ ln⟨χ⟩,

Minima of the fluctuations of the order parameter of global seismicity. Chaos, volume 25 (Article number 063110) and may be found at http://dx.doi.org/10.1063/1.4922300 . Copyright © and MoralRights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. Furthermore, the present results strengthen the view that the solid Earth crust behaves as a single complex system. CURVE is the Institutional Repository for Coventry University

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Synthesis, characterization and density functional theory calculations have been combined to examine the formation of the Zr 3 (Al 1-x Si x )C 2 quaternary MAX phases and the intrinsic defect processes in Zr 3 AlC 2 and Zr 3 SiC 2 . The MAX phase family is extended by demonstrating that Zr 3 (Al 1-x Si x )C 2 , and particularly compositions with x%0.1, can be formed leading here to a yield of 59 wt%. It has been found that Zr 3 AlC 2 -and by extension Zr 3 (Al 1-x Si x )C 2 -formation rates benefit from the presence of traces of Si in the reactant mix, presumably through the in situ formation of Zr y Si z phase(s) acting as a nucleation substrate for the MAX phase. To investigate the radiation tolerance of Zr 3 (Al 1-x Si x )C 2 , we have also considered the intrinsic defect properties of the end-members. properties (high elastic stiffness, high melting temperature, high thermal shock resistance, good machinability, high thermal, and electrical conductivity). 2,6-12 Such properties drive their technological importance and are attributed to their structure, which consists of the stacking of n "ceramic" layer(s) interleaved by an A "metallic" layer. 2,[6][7][8] MAX phases crystallize with the hexagonal P6 3 /mmc space group (no. 194).1,2 The MAX phase family has three main forms, first M 2 AX (i.e., n=1) type which are commonly --