Macro Determinants of Individual Income Poverty in 93 Regions of Europe

The analysis of the at-risk-of-poverty determinants can be improved by taking into account factors at macro (regional) level. This hypothesis has already been made in previous research, at country-level, on cross-sectional data. We use longitudinal data in this analysis in order to get more precise estimated parameters, and we test if the regional unemployment rate and the regional GDP affect the individual at-risk-of-poverty status. The countries taken into account are those present in the Statistics on Income and Living Conditions (EU-SILC) dataset.income poverty; EU-SILC; multilevel models; longitudinal data

Optical Spectral Observations of a Flickering White-Light Kernel in a C1 Solar Flare

We analyze optical spectra of a two-ribbon, long duration C1.1 flare that occurred on 18 Aug 2011 within AR 11271 (SOL2011-08-18T15:15). The impulsive phase of the flare was observed with a comprehensive set of space-borne and ground-based instruments, which provide a range of unique diagnostics of the lower flaring atmosphere. Here we report the detection of enhanced continuum emission, observed in low-resolution spectra from 3600 \AA\ to 4550 \AA\ acquired with the Horizontal Spectrograph at the Dunn Solar Telescope. A small, $\le$0''.5 ($10^{15}$ cm$^2$) penumbral/umbral kernel brightens repeatedly in the optical continuum and chromospheric emission lines, similar to the temporal characteristics of the hard X-ray variation as detected by the Gamma-ray Burst Monitor (GBM) on the Fermi spacecraft. Radiative-hydrodynamic flare models that employ a nonthermal electron beam energy flux high enough to produce the optical contrast in our flare spectra would predict a large Balmer jump in emission, indicative of hydrogen recombination radiation from the upper flare chromosphere. However, we find no evidence of such a Balmer jump in the bluemost spectral region of the continuum excess. Just redward of the expected Balmer jump, we find evidence of a "blue continuum bump" in the excess emission which may be indicative of the merging of the higher order Balmer lines. The large number of observational constraints provides a springboard for modeling the blue/optical emission for this particular flare with radiative-hydrodynamic codes, which are necessary to understand the opacity effects for the continuum and emission line radiation at these wavelengths.Comment: 54 pages, 13 figures, accepted for publication in the Astrophysical Journa

Towards a Quantitative Comparison of Magnetic Field Extrapolations and Observed Coronal Loops

It is widely believed that loops observed in the solar atmosphere trace out magnetic field lines. However, the degree to which magnetic field extrapolations yield field lines that actually do follow loops has yet to be studied systematically. In this paper we apply three different extrapolation techniques - a simple potential model, a NLFF model based on photospheric vector data, and a NLFF model based on forward fitting magnetic sources with vertical currents - to 15 active regions that span a wide range of magnetic conditions. We use a distance metric to assess how well each of these models is able to match field lines to the 12,202 loops traced in coronal images. These distances are typically 1-2". We also compute the misalignment angle between each traced loop and the local magnetic field vector, and find values of 5-12$^\circ$. We find that the NLFF models generally outperform the potential extrapolation on these metrics, although the differences between the different extrapolations are relatively small. The methodology that we employ for this study suggests a number of ways that both the extrapolations and loop identification can be improved.Comment: Accepted for publication in Ap

A comparative analysis of formulations for the Hamiltonian p-Median Problem

Tese de Mestrado, Estatística e Investigação Operacional , 2022, Universidade de Lisboa, Faculdade de CiênciasIn this dissertation we study the Hamiltonian p-Median Problem, a combinatorial optimization problem in which, given an undirected graph G = (V, E) and a cost for each edge, the objective is to find the cheapest way to partition the set of nodes into p subsets with each subset being connected by a single cycle. This is a problem which may therefore be seen as a generalization of the Travelling Salesman Problem (TSP). When working with MILP models for the TSP, sets of constraints to prevent feasible solutions with more than one cycle are added to an assignment formulation. Similarly, when working with such models for the HpMP, sets of constraints to prevent feasible solutions with more than p cycles can also be added to an assignment formulation, and these are often very similar to sets of constraints already used in models for the TSP, albeit with some modifications. However, these sets are not sufficient to guarantee every feasible solution has exactly p cycles, since it may have fewer than p cycles. To this end, additional sets of constraints for preventing solutions with less than p cycles may be introduced, and these will be the focal point of this work. The work begins with a brief introduction to the problem and some literature review. After that, several compact formulations for this problem are presented. The presentation of these models will be split into three parts. In the first part, a model upon which all other models are built is presented. The second part focuses on a model used to prevent solutions with more than p cycles, while the third part focuses on two models used to prevent solutions with less than p cycles (in which nodes are assigned to depots or cycles), accompanied by some valid inequalities. Finally, some of the models presented in this work are tested and the results and possibilities for future work are discussed

A probabilistic validation approach for penalty function design in stochastic model predictive control

Cuenta con otro ed. : IFAC-PapersOnLine Incluída en el vol. 53, Issue 2 Article number 145388In this paper, we consider a stochastic Model Predictive Control able to account for effects of additive stochastic disturbance with unbounded support, and requiring no restrictive assumption on either independence nor Gaussianity. We revisit the rather classical approach based on penalty functions, with the aim of designing a control scheme that meets some given probabilistic specifications. The main difference with previous approaches is that we do not recur to the notion of probabilistic recursive feasibility, and hence we do not consider separately the unfeasible case. In particular, two probabilistic design problems are envisioned. The first randomization problem aims to design offline the constraint set tightening, following an approach inherited from tube-based MPC. For the second probabilistic scheme, a specific probabilistic validation approach is exploited for tuning the penalty parameter, to be selected offline among a finite-family of possible values. The simple algorithm here proposed allows designing a single controller, always guaranteeing feasibility of the online optimization problem. The proposed method is shown to be more computationally tractable than previous schemes. This is due to the fact that the sample complexity for both probabilistic design problems depends on the prediction horizon in a logarithmic way, unlike scenario-based approaches which exhibit linear dependence. The efficacy of the proposed approach is demonstrated with a numerical example.Ministerio de Economía y Competitividad ( España)Ministerio de Educación, Universidad e Investigación de Italia 2017 PRIN 2017S559B

Opinion dynamics on directed small-world networks

In this paper, we investigate the self-affirmation effect on formation of public opinion in a directed small-world social network. The system presents a non-equilibrium phase transition from a consensus state to a disordered state with coexistence of opinions. The dynamical behaviors are very sensitive to the density of long-range interactions and the strength of self-affirmation. When the long-range interactions are sparse and individual generally does not insist on his/her opinion, the system will display a continuous phase transition, in the opposite case with high self-affirmation strength and dense long-range interactions, the system does not display a phase transition. Between those two extreme cases, the system undergoes a discontinuous phase transition.Comment: 6 pages, 5 figure

Productive water uses at household level in rural Kenya: case study of the Ukambani district

As a result of the growing world population and enhanced by the rising of living standards, competition for water is growing and this causes increased pressure on water resources worldwide. This tendency gave rise to the development of the integrated water resources management approach (IWRM), acknowledging the need to manage water resources in a holistic and integrated way. The IWRM objective to optimize economic, social and environmental outcomes of water management, can however only be reached if impact of water uses is correctly assessed. Nevertheless, often multiple uses of water within sectors are insufficiently recognized in planning and management. One of these neglected uses is the productive water use by households. Nonetheless, this use is extremely important to the livelihood of the poor, especially in the vast semi-arid rural areas of the developing world. An adequate evaluation of this use will not only help to improve outcome of water management, but will also add to the goal of poverty reduction. In this study, the role of productive water use for the rural community of the Ukambani district in Kenya was monitored, thereby focusing on income contributions and improvements in nutritional status

Health Care Provider Choice

In order to achieve an ‘optimal health system’ health policies should not only be focused on the supply of health care, but also take cognisance of the demand for health care. Studies of health care demand in South Africa are scarce due to considerable data limitations. This analysis attempts to fill this gap by combining two data sets (specifically, the GHS 2004 and IES/LFS 2000) in order to be able to utilize the wealth of information regarding health care utilization in the General Household Survey. The aim is to inform and encourage debate on how to incorporate demand side considerations in order to arrive at improved public health care in South Africa.health care, demand for health, combining data sets, South Africa

Dissipative surface solitons in periodic structures

We report dissipative surface solitons forming at the interface between a semi-infinite lattice and a homogeneous Kerr medium. The solitons exist due to balance between amplification in the near-surface lattice channel and two-photon absorption. The stable dissipative surface solitons exist in both focusing and defocusing media, when propagation constants of corresponding states fall into a total semi-infinite and or into one of total finite gaps of the spectrum (i.e. in a domain where propagation of linear waves is inhibited for the both media). In a general situation, the surface solitons form when amplification coefficient exceeds threshold value. When a soliton is formed in a total finite gap there exists also the upper limit for the linear gain.Comment: 5 pages, 3 figures, to appear in Europhysics Letter