Miracle-dz/UniFAR-FTUs huggingface dataset:
Stratospheric modulation of the large‐scale circulation in the Atlantic–European region and its implications for surface weather events

Extreme states of the stratospheric polar vortex can have long‐lasting impacts on extratropical circulation patterns, such as the North Atlantic Oscillation (NAO). This provides windows of subseasonal predictability beyond the typical weather forecast horizon of about 10 days. Subseasonal forecasts of surface weather are of significant interest in weather‐dependent socio‐economic sectors. For example, demand and supply for electricity and gas are weather dependent and therefore accurate forecasts are important for the energy industry and energy trading. Here we investigate the subseasonal impact of stratospheric conditions on surface weather events relevant to the energy industry in five subregions of Europe in winter. We use a definition of seven Atlantic–European weather regimes to describe the variability of the large‐scale circulation on subseasonal time scales. Results indicate that weather events are often associated with more than one preferred weather regime. In turn, some weather regimes project onto a specific NAO phase, while others are independent of the NAO. As expected, anomalous stratospheric polar vortex states predominantly modulate the occurrence of regimes related to the NAO and affect the likelihood of their associated weather events. In contrast, the occurrence of weather regimes which do not project well onto the NAO is not affected by anomalous stratospheric polar vortex states. These regimes provide pathways to unexpected weather events in extreme stratospheric polar vortex states. For example, weak stratospheric polar vortex states enhance the likelihood of negative NAO. High wind events in Central Europe predominantly occur during the zonal regime, strongly projecting onto positive NAO. However, these events also occur during the Atlantic trough regime, which is unaffected by anomalous stratospheric polar vortex states and thus provides a pathway to Central European high wind events during weak stratospheric polar vortex states. A correct NAO prediction alone is therefore not sufficient to correctly predict surface weather after extreme stratospheric polar vortex states. Moreover, weather regime life cycles independent of the NAO also need to be forecast accurately.
Convex Optimization Techniques for Geometric Covering Problems

The present thesis is a commencement of a generalization of covering results in specific settings, such as the Euclidean space or the sphere, to arbitrary compact metric spaces. In particular we consider coverings of compact metric spaces $(X,d)$ by balls of radius $r$. We are interested in the minimum number of such balls needed to cover $X$, denoted by $\Ncal(X,r)$. For finite $X$ this problem coincides with an instance of the combinatorial \textsc{set cover} problem, which is $\mathrm{NP}$-complete. We illustrate approximation techniques based on the moment method of Lasserre for finite graphs and generalize these techniques to compact metric spaces $X$ to obtain upper and lower bounds for $\Ncal(X,r)$. \\ The upper bounds in this thesis follow from the application of a greedy algorithm on the space $X$. Its approximation quality is obtained by a generalization of the analysis of Chv\'atal's algorithm for the weighted case of \textsc{set cover}. We apply this greedy algorithm to the spherical case $X=S^n$ and retrieve the best non-asymptotic bound of B\"or\"oczky and Wintsche. Additionally, the algorithm can be used to determine coverings of Euclidean space with arbitrary measurable objects having non-empty interior. The quality of these coverings slightly improves a bound of Nasz\'odi. \\ For the lower bounds we develop a sequence of bounds $\Ncal^t(X,r)$ that converge after finitely (say $\alpha\in\N$) many steps: $$\Ncal^1(X,r)\leq \ldots \leq \Ncal^\alpha(X,r)=\Ncal(X,r). $$ The drawback of this sequence is that the bounds $\Ncal^t(X,r)$ are increasingly difficult to compute, since they are the objective values of infinite-dimensional conic programs whose number of constraints and dimension of underlying cones grow accordingly to $t$. We show that these programs satisfy strong duality and derive a finite dimensional semidefinite program to approximate $\Ncal^2(S^2,r)$ to arbitrary precision. Our results rely in part on the moment methods developed by de Laat and Vallentin for the packing problem on topological packing graphs. However, in the covering problem we have to deal with two types of constraints instead of one type as in packing problems and consequently additional work is required.
The Clinical Impact of Earlier Detection of Methicillin-Resistant Staphylococcus Aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of infections in hospital, and recently, community settings. Earlier detection of MRSA in clinical specimens could result in earlier treatment and improved clinical outcomes of patients with MRSA infections. The objective of this study was to evaluate the clinical impact of a rapid latex agglutination test (RLAT) used to detect MRSA earlier. Methods: A retrospective doublecohort study was conducted on 258 patients with MRSA infections. Results: In the group who had MRSA cultured from a non-sterile body site, the odds of receiving early treatment were higher in patients whose MRSA were initially detected with the RLAT versus standard testing (Odds Ratio: 4.6, 95% CI 2.5-8.6). After adjusting for covariates, the RLAT was not associated with a decrease in length of stay (p=0.13). Conclusion: The RLAT had clinical utility for prompting earlier treatment of MRSA infections; however, it was not shown to significantly improve the clinical outcome of patients with MRSA infections. Further research is needed to elucidate the impact of the RLAT on the clinical outcomes of patients with MRSA infections.
A stochastic maximum principle for switching diffusions using conditional mean-fields with applications to control problems

This paper obtains a maximum principle for switching diffusions with mean-field interactions. The motivation stems from a wide range of applications for networked control systems in which large-scale systems are encountered and mean-field interactions are involved. Because of the complexity due to the switching, little has been done for the associate control problems with mean-field interactions. The main ingredient of this work is the use of conditional mean-fields, which is distinct from the existing literature. Using the maximum principle, optimal controls of linear quadratic Gaussian controls with mean-field interactions for switching diffusions are carried out. Numerical examples are also provided for demonstration.
Effective Secrecy Rate for a Downlink NOMA Network

In this paper, a novel approach is introduced to study the achievable delay-guaranteed secrecy rate, by introducing the concept of the effective secrecy rate (ESR). This study focuses on the downlink of a non-orthogonal multiple access (NOMA) network with one base station, multiple single-antenna NOMA users and an eavesdropper. Two possible eavesdropping scenarios are considered: 1) an internal, unknown, eavesdropper in a purely antagonistic network; and 2) an external eavesdropper in a network with trustworthy peers. For a purely antagonistic network with an internal eavesdropper, the only receiver with a guaranteed positive ESR is the one with the highest channel gain. A closed-form expression is obtained for the ESR at high signal-to-noise ratio (SNR) values, showing that the strongest user’s ESR in the high SNR regime approaches a constant value irrespective of the power coefficients. Furthermore, it is shown the strongest user can achieve higher ESR if it has a distinctive advantage in terms of channel gain with respect to the second strongest user. For a trustworthy NOMA network with an external eavesdropper, a lower bound and an upper bound on the ESR are proposed and investigated for an arbitrary legitimate user. For the lower bound, a closed-form expression is derived in the high SNR regime. For the upper bound, the analysis shows that if the external eavesdropper cannot attain any channel state information (CSI), the legitimate NOMA user at high SNRs can always achieve positive ESR, and the value of it depends on the power coefficients. Simulation results numerically validate the accuracy of the derived closed-form expressions and verify the analytical results given in the theorems and lemmas.
Massive MIMO–NOMA Networks With Multi-Polarized Antennas

This paper aims to design and evaluate the performance of multi-cluster multi-user dual-polarized massive multiple-input multiple-output (MIMO) systems with non-orthogonal multiple access (NOMA). Assuming the downlink mode in which a single base station communicates with multiple users, with all terminals being equipped with multiple co-located dual-polarized antennas, two precoder designs are proposed: (i) the first one aims to maximize the number of user groups that are simultaneously served within a cluster; and (ii) the second approach aims to provide further improvements compared to the first one by exploring polarization diversity. Closed-form expressions for the outage probability are derived for both approaches, based on which the respective asymptotic studies are carried out and the diversity gains are determined. The ergodic sum-rates are also derived. Representative numerical examples are presented along with insightful discussions. For instance, our results show that the proposed dual-polarized MIMO-NOMA designs outperform conventional single-polarized systems, even for high cross-polar interference. Simulation results are plotted to corroborate the analytical framework and analysis.
Nonstandard finite difference method for nonlinear Riesz space fractional reaction-diffusion equation

In this paper, a modified nonstandard finite difference method for the two-dimensional Riesz space fractional reaction-diffusion equations is developed. The space fractional derivative is discretized by the shifted Grunwald-Letnikov method and the nonlinear reaction term is approximated by Taylor formula instead of Micken’s. Multigrid method is introduced to reduce the computation time of the traditional Gauss-Seidal method. The stability and convergence of the nonstandard implicit difference scheme are strictly proved. The method is extended to simulate the fractional FitzHugh-Nagumo model. Numerical results are provided to verify the theoretical analysis.
Soft Magnetoactive Laminates: Large Deformations, Transverse Elastic Waves and Band Gaps Tunability by a Magnetic Field

We investigate the behavior of soft magnetoactive periodic laminates under remotely applied magnetic field. We derive explicit formulae for the induced deformation due to magnetic excitation of the laminates with hyperelastic magnetoactive phases. Next, we obtain the closed-form formulae for the velocities of long transverse waves. We show the dependence of the wave velocity on the applied magnetic intensity and induced strains, as well as on the wave propagation direction. Based on the long wave analysis, we derive closed-form formulae for the critical magnetic field corresponding to the loss of macroscopic stability. Finally, we analyze the transverse wave band gaps appearing in magnetoactive laminates in the direction normal to the layers. We illustrate the band gap tunability—width and position—by magnetically induced deformation.
Impact of a sharp, small‐scale SST front on the marine atmospheric boundary layer on the Iroise Sea: Analysis from a hectometric simulation

The impact of a sharp, small‐scale sea‐surface temperature (SST) front located in the Iroise Sea off the northwestern coast of France on the marine atmospheric boundary layer (MABL) is investigated using a realistic very high‐resolution numerical simulation. The modelling configuration is based on a two‐way nesting of the atmospheric model Meso‐NH over three embedded domains, with horizontal resolution of 100 m in the central domain. The outer mesoscale domain is initialized and forced on its lateral boundaries with the operational analyses of Météo‐France. A high‐resolution, realistic SST field from the Model for Application at Regional Scale (MARS) 3D is used as surface forcing. This configuration has been carefully designed to accurately represent this weak‐wind situation highly inhomogeneous in space and time, with wind flowing from the warm to the cold side of the front. The impacts include a slight modification of the thermal structure of the MABL, and a strong and rapid decrease of the wind speed, wind stress and turbulent heat fluxes. Conversely to previously published work, the coupling of the wind stress with the SST is largely related to atmospheric stability effects rather than to the change of the surface wind speed. This is attributed to the conjunction of the weak wind speed around 3 m s−1 and of the narrowness of the front resulting in relatively strong advection. These characteristics explain the momentum budget with strong change of the turbulent mixing over a shorter length‐scale than the pressure adjustment mechanism and the Coriolis term. The deceleration and counter‐clockwise veering of the near‐surface wind over colder water is consistent with previous work. Its attribution to turbulent mixing via a thermal stratification change in the context of a realistic study of a sharp front is a novel result.
A converse of the mean value theorem

2. A DIFFERENT VIEW OF THE MEAN VALUE THEOREM. The mean value theorem is: If f is continuous on [a, b] and differentiable on (a, b), then there is some c c (a, b) such that f'(c) = (f(b) f(a))/(b a). Alternatively, it can be expressed geometrically as: If f is continuous on [a, b] and differentiable on (a, b) then for any subinterval (al, bl) c [a, b], there is a tangent line at a certain point (c, f(c)) that is parallel to the secant line passing through (al, t(al)) and (bl, t(bl)). We consider the converse: given a tangent line passing through (c, f(c)), is there a secant line passing through some points (al, t(al )) and (b I, t(bl )) that is parallel to it? The fundamental question we discuss is more precisely expressed as, for each c c (a, b), is there a nonempty sub-interval (al, bl) c [a, b] such that f'(c) = (f(bl) -f(al))/(bl al)? We consider the strong form of the converse in which c c (al, bl) and the weak form, which does not require c c (al, bl). Geometrically, the strong form requires the secant line with slope f'(c) to intersect the graph of f on opposite sides of c, whereas the secant line need not intersect the graph of f on opposite sides of c in the weak form. A simple example shows that the converse need not hold in either the strong or weak forms. If f(x) = X3 on [ 1, 1], then f'(O) = O but (f(bl ) f(al ))/(bl al ) = (b3 a3)/(bl al) > O whenever -1 < al < bl < 1. In the following theorem we give the converse theorem in both the weak and strong forms.
EDGAR v4.3.2 Global Atlas of the three major greenhouse gas emissions for the period 1970–2012

Abstract. The Emissions Database for Global Atmospheric Research (EDGAR) compiles anthropogenic emissions data for greenhouse gases (GHGs), and for multiple air pollutants, based on international statistics and emission factors. EDGAR data provide quantitative support for atmospheric modelling and for mitigation scenario and impact assessment analyses as well as for policy evaluation. The new version (v4.3.2) of the EDGAR emission inventory provides global estimates, broken down to IPCC-relevant source-sector levels, from 1970 (the year of the European Union's first Air Quality Directive) to 2012 (the end year of the first commitment period of the Kyoto Protocol, KP). Strengths of EDGAR v4.3. 2 include global geo-coverage (226 countries), continuity in time, and comprehensiveness in activities. Emissions of multiple chemical compounds, GHGs as well as air pollutants, from relevant sources (fossil fuel activities but also, for example, fermentation processes in agricultural activities) are compiled following a bottom-up (BU), transparent and IPCC-compliant methodology. This paper describes EDGAR v4.3. 2 developments with respect to three major long-lived GHGs (CO2, CH4, and N2O) derived from a wide range of human activities apart from the land-use, land-use change and forestry (LULUCF) sector and apart from savannah burning; a companion paper quantifies and discusses emissions of air pollutants. Detailed information is included for each of the IPCC-relevant source sectors, leading to global totals for 2010 (in the middle of the first KP commitment period) (with a 95 % confidence interval in parentheses): 33.6(±5.9) Pg CO2 yr−1, 0.34(±0.16) Pg CH4 yr−1, and 7.2(±3.7) Tg N2O yr−1. We provide uncertainty factors in emissions data for the different GHGs and for three different groups of countries: OECD countries of 1990, countries with economies in transition in 1990, and the remaining countries in development (the UNFCCC non-Annex I parties). We document trends for the major emitting countries together with the European Union in more detail, demonstrating that effects of fuel markets and financial instability have had greater impacts on GHG trends than effects of income or population. These data (https://doi.org/10.5281/zenodo.2658138, Janssens-Maenhout et al., 2019) are visualised with annual and monthly global emissions grid maps of 0.1∘×0.1∘ for each source sector.
Use of statistical analysis, data mining, decision analysis and cost effectiveness analysis to analyze medical data: Application to comparative effectiveness of lumpectomy and mastectomy for breast cancer

USE OF STATISTICAL ANALYSIS, DATA MINING, DECISION ANALYSIS AND COST EFFECTIVENESS ANALYSIS TO ANALYZE MEDICAL DATA: APPLICATION TO COMPARATIVE EFFECTIVENESS OF LUMPECTOMY AND MASTECTOMY FOR BREAST CANCER Beatrice Ugiliweneza November 4t\ 2011 Statistical models have been the first choice for comparative effectiveness in clinical research. Though effective, these models are limited when the data to be analyzed do not fit the assumed distributions; which is mostly the case when the study is not a clinical trial. In this project, data mining, decision analysis and cost effectiveness analysis methods were used to supplement statistical models in comparing lumpectomy to mastectomy for surgical treatment of breast cancer. Mastectomy has been the gold standard for breast cancer treatment for since the 1800s. In the 20 century, an equivalence of mastectomy and lumpectomy was established in terms of long-term survival and disease free survival. However, short term comparative effectiveness in post-operative outcomes has not been fully explored. Studies using administrative data are lacking and no study has used new technologies of self-expression, particularly the internet discussion board. In this study, data used were from the Nationwide Inpatient
Slow convergence to equilibrium for an evolutionary epidemiology integro-differential system

This work is devoted to the study of an integro-differential system of equations modelling the genetic adaptation of a pathogen by taking into account both mutation and selection processes. Using the variance of the dispersion in the phenotype trait space as a small parameter we provide a complete picture of the dynamical behaviour of the solutions of the problem. We show that the dynamics exhibits two main and long regimes – those durations are estimated – before the solution finally reaches its long time configuration, the endemic equilibrium. The analysis provided in this work rigorously explains and justifies the complex behaviour observed through numerical simulations of the system.
Mimetic DBI Inflation in Confrontation with Planck2018 Data

We study mimetic gravity in the presence of a Dirac–Born–Infeld (DBI)-like term, which is a non-canonical setup of the scalar field’s derivatives. We consider two general cases with varying and constant sound speeds and construct the potentials for both the DBI and mimetic DBI (MDBI) models. By considering the power-law scale factor as a = a0tn, we search for the observational viability of these models. We show that the MDBI model in some ranges of the parameter space is free from ghost and gradient instabilities. By studying the behavior of r–ns and αs–ns in confrontation with Planck2018 data, we find some constraints on the model’s parameters. We show that, for the case with varying sound speed, power-law DBI inflation is not consistent with Planck2018 TT, TE, EE+lowE+lensing data, but the MDBI inflation is consistent with the same data at 95% confidence level, in some ranges of the model’s parameter space such as 40 ≤ n ≤ 55; the model is also free from instabilities in these ranges of parameters. For a constant sound speed, we study both DBI and MDBI models numerically by adopting some sample values of cs, and find n ∼ 102 for the DBI model and n ∼ 10 for the MDBI model. We also compare the results with Planck2018 TT, TE, EE+lowE+lensing+BK14+BAO data and see that the DBI and MDBI models with varying sound speed are ruled out by these joint data. However, these models with constant sound speed are consistent with the same data, with n ∼ 102 for the DBI model and n ∼ 10 for the MDBI model. In this case, we find some tighter constraints on the corresponding sound speed.
PENGARUH FREE CASH FLOW DAN LEVERAGE TERHADAP HARGA SAHAM DENGAN KEBIJAKAN DIVIDEN SEBAGAI VARIABEL INTERVENING

ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh free cash flow dan leverage terhadap harga saham dengan menggunakan kebijakan dividen sebagai variabel intervening, dimana kebijakan dividen diproksikan dengan dividend payout ratio (DPR). Penelitian ini menggunakan pendekatan kuantitatif dan analisis dilakukan menggunakan metode analisis jalur ( path analysis) . Sampel penelitian diambil dari industri manufaktur di Bursa Efek Indonesia (BEI) selama kurun waktu 2010 – 2014 dengan metode purposive sampling . Diperoleh 16 perusahaan sebagai sampel, yang diobservasi selama 5 tahun dengan total observasi sebanyak 80. Hasil penelitian menunjukkan bahwa free cash flow dan leverage memiliki pengaruh langsung yang signifikan terhadap harga saham. Pengaruh langsung free cash flow terhadap kebijakan dividen adalah signifikan, sedangkan l everage tidak berpengaruh terhadap kebijakan dividen. Hasil penelitian juga menunjukkan bahwa kebijakan dividen tidak dapat memediasi pengaruh free cash flow dan leverage terhadap harga saham. Kata kunci: free cash flow, leverage , harga saham, kebijakan dividen.