In the current pandemic context, it is necessary to remember the lessons learned from previous outbreaks in Africa, where the incidence of other diseases could rise if most resources are directed to ...tackle the emergency. Improving the access to water, sanitation and hygiene (WASH) could be a win-win strategy, because the lack of these services not only hampers the implementation of preventive measures against SARS-CoV-2 (e.g. proper handwashing), but it is also connected to high mortality diseases (for example, diarrhoea and lower respiratory infections (LRI)). This study aims to build on the evidence-based link between other LRI and WASH as a proxy for exploring the potential vulnerability of African countries to COVID-19, as well as the role of other socioeconomic variables such as financial sources or demographic factors. The selected methodology combines several machine learning techniques to single out the most representative variables for the analysis, classify the countries according to their capacity to tackle public health emergencies and identify behavioural patterns for each group. Besides, conditional dependences between variables are inferred through a Bayesian network. Results show a strong relationship between low access to WASH services and high LRI mortality rates, and that migrant remittances could significantly improve the access to healthcare and WASH services. However, the role of Official Development Assistance (ODA) in enhancing WASH facilities in the most vulnerable countries cannot be disregarded, but it is unevenly distributed: for each 50–100 US$ of ODA per capita, the probability of directing more than 3 US$ to WASH ranges between 48% (Western Africa) and 8% (Central Africa).
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•Most African countries are still highly vulnerable to infectious respiratory diseases.•Low access to WASH services increases the probability of having a high LRI mortality.•Remittances improve the access to WASH and healthcare services at household level.•Vulnerable countries depend on ODA for WASH access, but it is unevenly distributed.•Well-targeted ODA could alleviate the effects of reduced remittances due to COVID-19.
Self-assessment and peer assignment have clear advantages for the training of responsible, critical, and reflective professionals. In recent years, self and peer evaluation have also been shown to be ...even more effective than lecturer evaluation when we assure anonymity through online platforms learning tools. Therefore, self and peer assessments are to become a core aspect of student-centred evaluation processes in Higher Education. Besides, a high concordance with lecturer evaluation may allow lecturers to also benefit from self and peer evaluation without an increase in their workload. In the present work, we compare the formative evaluation from the lecturer with the self and peer assessments through a virtual learning environment. The subject of study if formed by assessments prepared by students in a first-year course in a Social Sciences degree at the Universidade de Vigo, Spain. We find a strong concordance between peer assessment and lecturer assignment, and a moderate agreement between self-assessment and lecturer assignment. These results show that students perform well as peer evaluators, with peer assignment being a procedure with high validity and reliability.
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Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We consider a cost allocation problem arising from a hub network problem design. Finding an optimal hub network is NP-hard, so we start with a hub network that could be optimal or not. Our main ...objective is to divide the maintenance and/or building cost of such network among the nodes. We consider two cases. In the one-way flow case, we assume that the cost paid by a set of nodes depends only on the flow they send to other nodes (including nodes outside the set), but not on the flow they receive from nodes outside. In the two-way flow case, we assume that the cost paid by a set of nodes depends on the flow they send to other nodes (including nodes outside the set) and also on the flow they receive from nodes outside. In both cases, we study the core and the Shapley value of the corresponding cost game.
Despite the efforts made towards the Millennium Development Goals targets during the last decade, improved access to water supply or basic sanitation still remains unavailable for millions of people ...across the world. This paper proposes a set of models that use 25 key variables and country profiles from the WatSan4Dev data set involving water supply and sanitation (Dondeynaz et al., 2012). This paper suggests the use of Bayesian network modelling methods because they are more easily adapted to deal with non-normal distributions, and integrate a qualitative approach for data analysis. They also offer the advantage of integrating preliminary knowledge into the probabilistic models. The statistical performance of the proposed models ranges between 20 and 5% error rates, which are very satisfactory taking into account the strong heterogeneity of variables. Probabilistic scenarios run from the models allow an assessment of the relationships between human development, external support, governance aspects, economic activities and water supply and sanitation (WSS) access. According to models proposed in this paper, gaining a strong poverty reduction will require the WSS access to reach 75-76% through: (1) the management of ongoing urbanisation processes to avoid slums development; and (2) the improvement of health care, for instance for children. Improving governance, such as institutional efficiency, capacities to make and apply rules, or control of corruption is positively associated with WSS sustainable development. The first condition for an increment of the HDP (human development and poverty) remains of course an improvement of the economic conditions with higher household incomes. Moreover, a significant country commitment to the environment, associated with civil society freedom of expression constitutes a favourable setting for sustainable WSS services delivery. Intensive agriculture using irrigation practises also appears as a mean for sustainable WSS thanks to multi-uses and complementarities. With a WSS sector organised at national level, irrigation practices can support the structuring and efficiency of the agriculture sector. It may then induce rural development in areas where WSS access often is set back compared to urban areas super(1). External financial support, called Official Development Assistance (ODA CI), plays a role in WSS improvement but comes last in the sensitivity analyses of models. An overall 47% of the Official Development Assistance goes first to poor countries, and is associated to governance aspects: (1) political stability and (2) country commitment to the environment and civil society degree of freedom. These governance aspects constitute a good framework for aid implementation in recipient countries. Modelling is run with the five groups of countries as defined in Dondeynaz et al. (2012). Models for profile 4 (essential external support) and profile 5 (primary material consumption) are specifically detailed and analysed in this paper. For countries in profile 4, fighting against water scarcity and progressing desertification should be the priority. However, for countries in profile 5, efforts should first concentrate on consolidation of political stability while supporting diversification of the economic activities. Nevertheless, for both profiles, reduction of poverty should remain the first priority as previously indicated. super(1) JMP statistics, 2004 http://www.wssinfo.org/data-estimates/table/, last access: 22 July 2013.
We study minimum cost spanning tree problems and define a cost sharing rule that satisfies many more properties than other rules in the literature. Furthermore, we provide an axiomatic ...characterization based on monotonicity properties.
Proper tuning of hyper-parameters is essential to the successful application of SVM-classifiers. Several methods have been used for this problem: grid search, random search, estimation of ...distribution Algorithms (EDAs), bio-inspired metaheuristics, among others. The objective of this paper is to determine the optimal method among those that recently reported good results: Bat algorithm, Firefly algorithm, Fruit-fly optimization algorithm, particle Swarm optimization, Univariate Marginal Distribution Algorithm (UMDA), and Boltzmann-UMDA. The criteria for optimality include measures of effectiveness, generalization, efficiency, and complexity. Experimental results on 15 medical diagnosis problems reveal that EDAs are the optimal strategy under such criteria. Finally, a novel performance index to guide the optimization process, that improves the generalization of the solutions while maintaining their effectiveness, is presented.
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•Hardmetal with less toxic and more economical alternative binder to Co.•Nanostructured and highly homogeneous hardmetal powder obtained by HEBM.•Nanopowder with early densification ...and large contribution of solid state sintering.
WC cemented carbides with a greener alternative binder to Co, AISI 304 stainless steel (SS), were processed through high energy ball milling (HEBM). The milling parameters, such as rotation speed, ball-to-powder ratio and milling time were investigated. Selected milling conditions were applied to obtain a nanosized powder of WC-12 wt% SS with a highly uniform distribution of the ductile phase. For comparison, a conventionally wet milled powder was also prepared. Both powders were thermally characterized by dilatometry, up to 1450 °C, using vacuum atmosphere, and structural and microstructural analysis were performed in the sintered samples. The nanometric size of the HEBM powder particles markedly affected its densification and thermal reactivity; when compared with the micrometric powder obtained from conventional milling, early starting densification, with a greater contribution of solid state sintering, and increased reactivity, with formation of a larger amount of (M,W)6C phase, was noticed during sintering of HEBM powder compacts.
Schedule‐induced polydipsia (SIP) is an animal model of compulsive drinking that selects for individual differences and varies across rat strains. The aim of this study was to investigate excessive ...habit formation by analyzing the SIP licking microstructure among rat strains, and to compare the brain areas activated by SIP in different populations. Wistar, Long Evans and Roman High‐ and Low‐Avoidance rat strains were compared using a cluster analysis of 2 main variables, that is, frequency of licking (percentage of interpellet intervals with drinking episodes) and intensity of licking (mean number of licks per interpellet interval), and were found to exhibit high intensity and frequent licking (compulsive drinkers, CD), low intensity but frequent licking (habitual drinkers, HD), and low intensity and low‐frequency licking (low drinkers, LD). The Wistar strain showed a higher frequency and intensity of licking, and had the largest group of CD rats when compared with the other strains. Regarding the acquisition of SIP, CD rats showed a higher intensity of licking when compared with the HD and LD rats. Moreover, c‐Fos quantification revealed that rats in the CD group showed hyperactivity in the lateral orbitofrontal cortex and basolateral amygdala when compared with the LD group. Analyzing the SIP microstructure could be a valuable tool for understanding the role of excessive habit formation in the development of compulsive drinking and its underpinning neurobiological mechanisms.
Excessive habit formation measured by frequency and intensity of licking in schedule‐induce polydipsia among rat strains
Glaciers supply multiple ecosystem services that are threatened by climate change. The retreat and disappearance of tropical glaciers is an important dynamic that affects ecosystems and local ...communities. The knowledge of the impacts of this land-change dynamics on the supply of ecosystem services is lacking. In that sense, the assessment developed can provide evidence about the costs and benefits of promoting conservation and human well-being at the same time. Then, the main objective of this research is to determine the spatial–temporal changes and their effects on the economic value of ecosystem services in a glacial retreat environment. We selected the Marangani district as a study area. It comprises the La Raya Mountain range in the Andes. The assessments were carried out across two scales of observation: the municipality and the watershed level. Here, we process spectral information from Landsat Sensor using the Random Forest algorithm in the Google Earth Engine platform to classify 10 biomes. It was carried out over more than 30 years (from 1986 to 2019). After that, ecosystem services provided by the biomes were valued using the transfer method. This research shows that at the municipality level, almost all the LULCs faced variations over time, and the glaciers had the highest change, accumulating a ratio of –85.51%, whereas at the watershed level, a higher tendency of land changes is observed in the areas without glaciers, and those with glacier areas count on permanent larger bofedales. At the municipality level, the economic value of ecosystems shows that bofedales and water surfaces are the LULCs that supply the highest ecosystem services (∼33,000 USD ha
−1
yr
−1
each). In addition, without the inflation adjustment, the total ESV is on a trajectory of losing ESV (–$9.67 × 10
6
). In the watersheds with glacier retreat, significant quantity of bofedales and natural grasslands controls the fluctuations of ESV. These high-mountain watersheds play an essential role in providing benefits and value to local communities. In general, the municipality level indicates the trajectory of changes in the district, whereas the watershed scale shows the urgency for implementing spatial conservation actions.
Estimation of Distribution Algorithms (EDAs) maintain and iteratively update a probabilistic model to tackle optimization problems. The Boltzmann Probability Distribution Function (Boltzmann-PDF) ...provides advantages when used in energy based EDAs. However, direct sampling from the Boltzmann-PDF to update the probabilistic model is unpractical, and several EDAs employ an approximation to the Boltzmann-PDF by means of a Gaussian distribution that is usually derived by the minimization of the Kullback-Leibler divergence (KL-divergence) computed between the Gaussian and the Boltzmann-PDFs. The KL-divergence measure is not symmetric, and this causes the Gaussian approximation to fail at correctly modeling the target function for the EDAs, because the parameters of the Gaussian are not optimally estimated. In this paper, we derive an approximation to the Boltzmann-PDF using Jeffreys' divergence (a symmetric measure) in lieu of the KL-divergence and thus improve the performance of the optimization algorithm. Our approach is termed Symmetric-approximation Energy-based Estimation of Distribution (SEED) algorithm. The SEED algorithm is experimentally compared under a univariate approach against two other EDAs (UMDAc and BUMDA) on several benchmark optimization problems. The results show that the SEED algorithm is more effective and more efficient than the other algorithms.
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