Random Utility Theory for Social Choice

Random utility theory models an agent's preferences on alternatives by drawing a real-valued score on each alternative (typically independently) from a parameterized distribution, and then ranking the alternatives according to scores. A special case that has received significant attention is the Plackett-Luce model, for which fast inference methods for maximum likelihood estimators are available. This paper develops conditions on general random utility models that enable fast inference within a Bayesian framework through MC-EM, providing concave loglikelihood functions and bounded sets of global maxima solutions. Results on both real-world and simulated data provide support for the scalability of the approach and capability for model selection among general random utility models including Plackett-Luce.Engineering and Applied Science

Rainfall, fire and large-mammal-induced drivers of Vachellia drepanolobium establishment: Implications for woody plant encroachment in Maswa, Tanzania

This research article published by John Wiley & Sons, Inc., 2021Worldwide, open grass areas of savannah ecosystems are being transformed into shrubland. This woody plant encroachment is likely a result of factors such as rainfall, fire and secondary dispersal by ungulate herbivory. However, few experiments have been conducted to disentangle and quantify the role of these factors for seed germination in savannahs. We assessed in situ germination success of Vachellia drepanolobium seeds under simulated rainfall variability patterns, fire treatments and dung experiments in Maswa Game Reserve, Tanzania. Fire reduced seed germination by more than 13%, whereas germination in buffalo and elephant dung increased by 1% and 3% respectively. Additionally, intermediate simulated rainfall was more beneficial for seedling emergence success than large, infrequent simulated rainfall amounts, while shoot growth was twice as high under frequent and intermediate simulated rainfall treatments than under large infrequent simulated rainfall. Our results provide insights that bush fires, drought stress, and large rainfall events can suppress V. drepanolobium seedling emergence and growth. Hence, bush encroachment may be linked to management practices such as fire regimes and climatic conditions, i.e., frequent low rainfall conditions. Our results can help predict future patterns of encroachment under varying rainfall and fire events

An efficient and reliable scheduling algorithm for unit commitment scheme in microgrid systems using enhanced mixed integer particle swarm optimizer considering uncertainties

The use of an electrical energy storage system (EESS) in a microgrid (MG) is widely recognized as a feasible method for mitigating the unpredictability and stochastic nature of sustainable distributed generators and other intermittent energy sources. The battery energy storage (BES) system is the most effective of the several power storage methods available today. The unit commitment (UC) determines the number of dedicated dispatchable distributed generators, respective power, the amount of energy transferred to and absorbed from the microgrid, as well as the power and influence of EESSs, among other factors. The BES deterioration is considered in the UC conceptualization, and an enhanced mixed particle swarm optimizer (EMPSO) is suggested to solve UC in MGs with EESS. Compared to the traditional PSO, the acceleration constants in EMPSO are exponentially adapted, and the inertial weight in EMPSO decreases linearly during each iteration. The proposed EMPSO is a mixed integer optimization algorithm that can handle continuous, binary, and integer variables. A part of the decision variables in EMPSO is transformed into a binary variable by introducing the quadratic transfer function (TF). This paper also considers the uncertainties in renewable power generation, load demand, and electricity market prices. In addition, a case study with a multiobjective optimization function with MG operating cost and BES deterioration defines the additional UC problem discussed in this paper. The transformation of a single-objective model into a multiobjective optimization model is carried out using the weighted sum approach, and the impacts of different weights on the operating cost and lifespan of the BES are also analyzed. The performance of the EMPSO with quadratic TF (EMPSO-Q) is compared with EMPSO with V-shaped TF (EMPSO-V), EMPSO with S-shaped TF (EMPSO-S), and PSO with S-shaped TF (PSO-S). The performance of EMPSO-Q is 15%, 35%, and 45% better than EMPSO-V, EMPSO-S, and PSO-S, respectively. In addition, when uncertainties are considered, the operating cost falls from $8729.87 to$8986.98. Considering BES deterioration, the BES lifespan improves from 350 to 590, and the operating cost increases from $8729.87 to$8917.7. Therefore, the obtained results prove that the EMPSO-Q algorithm could effectively and efficiently handle the UC problem

Tratamiento quirúrgico e intervencionista de la coartación aórtica nativa en neonatos y lactantes

Introduction: Surgical relief of Coarctation of the aorta (CoA) and catheter interventional techniques are available alternatives even though no consensus has been reached in regard to the method of intervention (surgery vs. balloon angioplasty) in neonates and infants with native CoA. Many cardiologists prefer surgical intervention, whereas a few may choose for balloon angioplasty.Objective: To analyze surgical and interventional techniques outcomes in neonates and infants with native CoA. To identify the complications and the intensive care unit (ICU) stays. To determine the risk factors related to recoarctation (ReCoA).Method: An observational, analytical, longitudinal and prospective study was made aiming to analyze the surgical and balloon angioplasty outcomes in newborns and infants with native CoA at the William Soler Pediatric Cardiology Hospital from 2006 - 2011. Patients were distributed in two groups: Group I: patients treated with surgery (n=50); Group II: patients treated with angioplasty (n=14).Results: 75.0 % of patients in Group I and 57.1 % of the Group II were less than the six months old. ICU stays of patients treated surgically were the largest (median of 36 hours). The percentage of ReCoA was higher in patients treated with angioplasty (28.5 %). Paradoxical arterial hypertension was the most common complication found (60.0 %). A residual gradient higher than 15 mm Hg following surgical correction or balloon angioplasty was identified as a risk factor for ReCoA (interventional catheterization RR: 7.5; surgery RR: 11.4).Conclusions: ICU stays were longer in the patients underwent surgery. Patients treated with balloon angioplasty showed higher incidence of ReCoA. Complications were not so frequent. A gradient higher than 15 mm Hg was identified as a risk factor for ReCoA irrespective of the procedure performed.Introduction: le soulagement chirurgicale de coarctation de l'aorte (CoA) et le cathéter d'intervention techniques sont des alternatives disponibles, même si aucun consensus n'a été atteint en ce qui concerne la méthode d'intervention (chirurgie vs angioplastie par ballonnet) dans les nouveau-nés et les nourrissons avec natif CoA. Beaucoup de cardiologues préfèrent une intervention chirurgicale, tandis que quelques-uns peuvent choisir pour l'angioplastie par ballonnet. Objectif: analyser les techniques chirurgicales et interventionnelles résultats dans les nouveau-nés et les nourrissons avec natif CoA. Pour identifier les complications et les unités de soins intensifs (USI). Pour déterminer les facteurs de risque liés à recoarctation (ReCoA). Méthode: Une étude observationnelle analytique, longitudinale et prospective a été faite visant à analyser la chirurgie et l'angioplastie par ballonnet résultats des nouveau-nés et les nourrissons avec natif CoA à l'hôpital William Soler cardiologie pédiatrique de 2006 - 2011. patients ont été répartis en deux groupes: Groupe I : patients traités par chirurgie (n = 50); Groupe II: patients traités par angioplastie (n = 14). Résultats: 75,0% des patients du groupe I et 57,1% du groupe II étaient inférieures à la l'âge de six mois. Séjours aux soins intensifs des patients traités chirurgicalement ont le plus grand (médiane de 36 heures). Le pourcentage de ReCoA était plus élevée dans les patients traités à l'angioplastie (28,5%). L'hypertension artérielle paradoxale a été la complication la plus commune (60,0%). Un gradient résiduel supérieur à 15 mm Hg suivante chirurgicale correction ou l'angioplastie par ballonnet a été identifié comme un facteur de risque pour ReCoA (interventionnelle cathétérisme RR: 7,5; chirurgie RR: 11,4). Conclusions: séjours en soins intensifs étaient plus dans les patients ont été opérés. Les patients traités par angioplastie par ballonnet ont montré une incidence plus élevée de ReCoA. Les complications sont pas si fréquentes. Un gradient supérieur à 15 mm Hg a été identifiée comme un facteur de risque pour ReCoA quelle que soit l'intervention effectuée.Introdução: alívio cirúrgico da coarctação da aorta (CoA) e cateter intervencionista técnicas são alternativas disponíveis, embora nenhum consenso foi alcançado em relação ao método de intervenção (cirurgia vs angioplastia por balão) em recém-nascidos e lactentes com CoA nativa. Muitos cardiologistas preferem intervenção cirúrgica, enquanto que alguns podem optar por angioplastia com balão. Objetivo: Analisar a técnica cirúrgica e intervencionista resultados em recém-nascidos e lactentes com CoA nativa. Para identificar as complicações e Unidade de Terapia Intensiva (UTI) estadias. Para determinar os fatores de risco relacionados à recoartaram (RECOA). Método: um estudo observacional, analítico e prospectivo foi feito com o objetivo de analisar a cirurgia e balão de angioplastia resultados em recém-nascidos e lactentes com CoA nativa no William Soler Cardiologia Pediátrica do Hospital de 2006 - 2011. Os pacientes foram distribuídos em dois grupos: Grupo I : os doentes tratados com a cirurgia (n = 50); Grupo II: os doentes tratados com angioplastia (n = 14). Resultados: 75,0% dos pacientes do Grupo I e 57,1% do grupo II foram menores do que os seis meses de idade. Permanência na UTI de pacientes tratados cirurgicamente foram o maior (média de 36 horas). O percentual de RECOA foi maior nos pacientes tratados com angioplastia (28,5%). Hipertensão arterial paradoxal foi a complicação mais comum encontrada (60,0%). Um gradiente residual maior que 15 mm Hg após correção cirúrgica ou balão de angioplastia foi identificado como um fator de risco para RECOA (intervencionista RR cateterismo: 7,5; cirurgia RR: 11,4). Conclusões: permanência na UTI foram maiores quando os pacientes foram submetidos a cirurgia. Os pacientes tratados com angioplastia com balão mostrou maior incidência de RECOA. As complicações não foram tão freqüentes. Um gradiente maior que 15 mm Hg foi identificado como um fator de risco para RECOA independentemente do procedimento realizado.Introducción: La Coartación aórtica se puede resolver con cirugíao a través del intervencionismo. Aunque existe controversia, la mayor parte de los autores recomiendan laprimera para el tratamiento de la coartación aórtica nativa en menores de un año.Objetivos: Analizar losresultados de lacirugía y elcateterismo intervencionista en neonatos y lactantes con coartación de la aorta nativa. Identificar las complicaciones posprocedimiento y la estadía en la terapia intensiva .Determinar los factores de riesgo en la aparición de recoartación.Método: Se realizó un estudio observacional, analítico, prospectivo y longitudinal con el objetivo de analizar los resultados de la cirugía y el cateterismo intervencionista en recién nacidos y lactantes con Coartación de la Aorta nativa en el Cardiocentro Pediátrico“William Soler”, durante el período 2006 a 2011. Los pacientes se dividieron en dos grupos: Grupo I: pacientes operados (n=50); Grupo II: intervenidos por cateterismo intervencionista(n=14). Resultados: Los menores de 6 meses constituyeron 76,5% del grupo I y 57,1 % del grupo II. La estadía en laterapia intensiva fue mayor en los pacientes operados (mediana de 36 horas). El porciento de recoartación fue mayor en los pacientes llevados a hemodinámica (28,5 %). La complicación posprocedimiento más frecuente fue la hipertensión arterial paradójica (60 %). Elgradiente mayor de 15 mm Hg posproceder fue un factor de riesgo para la recidiva (hemodinamia RR: 7,5, cirugía RR: 11,4).Conclusiones: La estadía en la unidad de cuidados intensivos es mayor en los intervenidos quirúrgicamente. En la coartación aortica la recoartación es más frecuente en los tratados con angioplastia percutánea de balón. Las complicaciones son infrecuentes, y los pacientes con gradiente mayor de 15 mm Hg posprocedertienen un riesgo aumentado de recoartación en ambos grupos

Seroprevalence of hepatitis E virus (HEV) among male craft and manual workers in Qatar (2020–2021)

BackgroundThe rapid growth of Qatar in the last two decades has attracted a large influx of immigrant craft and manual workers (CMWs) seeking employment in jobs associated with food handling, domestic service, and construction. Nearly 60 % of Qatar's population are expatriates CMWs, including many from hyperendemic countries for HEV. Thus, estimating the seroprevalence of HEV in Qatar and understanding its epidemiology is essential for public health efforts to control HEV transmission in Qatar. MethodsBlood samples from 2670 CMWs were collected between 2020 and 2021. All samples were tested for HEV-IgG antibodies. Positive HEV-IgG samples were tested for HEV-IgM antibodies, and those positives were also tested for viral antigens using an HEV-Ag ELISA kit and HEV-RNA by RT-PCR to confirm current HEV infections. ResultsThe seroprevalence of HEV-IgG was 27.3 % (729/2670; 95 % CI: 25.6–29.0). Of those HEV-IgG positive, 8.23 % (60/729; 95 % CI: 6.30–10.5) were HEV-IgM positive. Of the IgM-positive samples, 2 were HEV-RNA positive (3.39 %; 95 % CI: 0.40–11.7), and 1 was HEV-Ag positive (1.69 %; 95 % CI: 0.04–9.09). In addition, HEV-IgG seroprevalence was associated with age and nationality, with the highest seroprevalence in participants from Egypt (IgG 60.0 %; IgM 5.56 %), Pakistan (IgG 59.0 %; IgM 2.24 %), Nepal (IgG 29.3 %; IgM 2.70 %), Bangladesh (IgG 27.8 %; IgM 2.45 %), and India (IgG 23.9 %; IgM 2.43 %). ConclusionIn this study, we showed that the seroprevalence of HEV among CMWs was slightly higher than what was previously reported among the urban population in Qatar (2013–2016).This report was made possible by GSRA8-L-1-0501-21022 and NPRP13S-0128–200,185 from the Qatar National Research Fund (a member of Qatar Foundation). The funders had no role in study design, data collection, analysis, the decision to publish, or the preparation of the manuscript. The statements made herein are solely the responsibility of the authors. This study was approved by IRB at Qatar University (QU-IRB 1558-EA/21)

3D Ruthenium Nanoparticle Covalent Assemblies from Polymantane Ligands for Confined Catalysis

The synthesis of metal nanoparticle (NP) assemblies stabilized by functional molecules is an important research topic in nanoscience, and the ability to control interparticle distances and positions in NP assemblies is one of the major challenges in designing and understanding functional nanostructures. Here, two series of functionalized adamantanes, bis-adamantanes, and diamantanes, bearing carboxylic acid or amine functional groups, were used as building blocks to produce, via a straightforward method, networks of ruthenium NPs. Both the nature of the ligand and the Ru/ligand ratio affect the interparticle distance in the assemblies. The use of 1,3-adamantanedicarboxylic acid allows the synthesis of three-dimensional (3D) networks of 1.7–1.9 nm Ru NPs presenting an interparticle distance of 2.5–2.7 nm. The surface interaction between Ru NPs and the ligands was investigated spectroscopically using a 13C-labeled ligand, as well as theoretically with density functional theory (DFT) calculations. We found that Ru species formed during the NP assembly are able to partially decarbonylate carboxylic acid ligands at room temperature. Decarbonylation of a carboxylic acid at room temperature in the presence of dihydrogen usually occurs on catalysts at much higher temperatures and pressures. This result reveals a very high reactivity of ruthenium species formed during the network assembly. The Ru NP networks were found to be active catalysts for the selective hydrogenation of phenylacetylene, reaching good selectivity toward styrene. Overall, we demonstrated that catalyst activity, selectivity, and NP network stability are significantly affected by Ru NP interparticle distance and electronic ligand effects. As such, these materials constitute a unique set that should allow a better understanding of the complex surface chemistry in carbon-supported metal catalysts

Advances, gaps and way forward in provision of climate services over the Greater Horn of Africa

The Greater Horn of Africa is prone to extreme climatic conditions, thus, making climate services increasingly important in supporting decision-making processes across a range of climate sensitive sectors. This study aims to provide a comprehensive review of the recent advances, gaps and challenges in the provision of climate services over the region, for each of the components of the Global Framework for Climate Services. The study explores various milestones that have been achieved toward climate service delivery. The achievements include improvement of station network coverage, and enhancing the capacity of member states to utilize various tools in data analysis and generate routine climate products. The advancement in science, and availability of High-Performance Computing has made it possible for forecast information to be provided from nowcasting to seasonal timescales. Moreover, operationalizing of the objective forecasting method for monthly and seasonal forecasts has made it possible to translate tercile forecasts for applications models. Additionally, innovative approaches to user engagement through co-production, communication channels, user-friendly interfaces, and dissemination of climate information have also been developed. Despite the significant progress that has been made in the provision of climate services, there are still many challenges and gaps that need to be overcome in order to ensure that these services are effectively meeting the needs of users. The research of the science underpinning climate variability, capacity building and stakeholder engagement, as well as improved data management and quality control processes are some of the gaps that exist over the region. Additionally, communication and dissemination of climate information, including timely warnings and risk communication, require improvement to reach diverse user groups effectively. Addressing these challenges will require strengthened partnerships, increased investment in capacity building, enhanced collaboration between the climate information producers and stakeholders, and the development of user-friendly climate products. Bridging these gaps will foster greater resilience to climate-related hazards and disasters in the Greater Horn of Africa and support sustainable development in the region

Characterizing the Qatar advanced-phase SARS-CoV-2 epidemic.

The overarching objective of this study was to provide the descriptive epidemiology of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic in Qatar by addressing specific research questions through a series of national epidemiologic studies. Sources of data were the centralized and standardized national databases for SARS-CoV-2 infection. By July 10, 2020, 397,577 individuals had been tested for SARS-CoV-2 using polymerase-chain-reaction (PCR), of whom 110,986 were positive, a positivity cumulative rate of 27.9% (95% CI 27.8-28.1%). As of July 5, case severity rate, based on World Health Organization (WHO) severity classification, was 3.4% and case fatality rate was 1.4 per 1,000 persons. Age was by far the strongest predictor of severe, critical, or fatal infection. PCR positivity of nasopharyngeal/oropharyngeal swabs in a national community survey (May 6-7) including 1,307 participants was 14.9% (95% CI 11.5-19.0%); 58.5% of those testing positive were asymptomatic. Across 448 ad-hoc testing campaigns in workplaces and residential areas including 26,715 individuals, pooled mean PCR positivity was 15.6% (95% CI 13.7-17.7%). SARS-CoV-2 antibody prevalence was 24.0% (95% CI 23.3-24.6%) in 32,970 residual clinical blood specimens. Antibody prevalence was only 47.3% (95% CI 46.2-48.5%) in those who had at least one PCR positive result, but 91.3% (95% CI 89.5-92.9%) among those who were PCR positive > 3 weeks before serology testing. Qatar has experienced a large SARS-CoV-2 epidemic that is rapidly declining, apparently due to growing immunity levels in the population

Woody Encroachment Extent and Its Associated Impacts on Plant and Herbivore Species Occurrence in Maswa Game Reserve, Tanzania

Research Article published by the Canadian Center of Science and Education Vol. 9, No. 3; 2019Habitat degradation caused by woody plant encroachment has been a common phenomenon in savanna ecosystems. An increasing woody plant cover in open grassland reduces grazing grounds and, consecutively, impacts mammalian herbivores, but structural changes and their associated impact have rarely been assessed and quantified. We analyzed the extent of woody plant encroachment via remote sensing and used transects and plots to assess encroaching woody plant species and their associated impacts on herbaceous plant and herbivore species in Maswa Game Reserve, Tanzania. We found that woody plant cover had increased by 0.5% to 2.6% per annum over the last thirty years, while in other parts of the park it has decreased by 0.5% to 1.5% per annum. Acacia drepanolobium was the dominant encroaching woody species, and the number of stems in heavily encroached sites was seven times and three times higher than in open grassland and at medium encroached sites, respectively. In encroached plots, grazer and mixed feeder species occurrence were reduced while the presence of browser species was slightly elevated. Furthermore, our findings show that bare ground cover is positively correlated with an increase of woody plant cover. Additionally, the number of herbaceous species slightly increased with the increase of woody plant encroachment, while the herbaceous cover was negatively correlated with the increase of woody plant cover. We suggest that fire regimes should be taken up to suppress the ongoing encroachment processes while strongly encroached sites might need mechanical intervention to control dense vegetation. This emphasis is on fire, particularly prescribed fire as a management tool of vegetation in Savanna ecosystem. We conclude that, woody plant encroachment is driven by different factors such as fire, mega-herbivores and topology that may interactively trigger woody plant encroachment in Savanna ecosystem