Computing (R, S) policies with correlated demand

This paper considers the single-item single-stocking non-stationary stochastic lot-sizing problem under correlated demand. By operating under a nonstationary (R, S) policy, in which R denote the reorder period and S the associated order-up-to-level, we introduce a mixed integer linear programming (MILP) model which can be easily implemented by using off-theshelf optimisation software. Our modelling strategy can tackle a wide range of time-seriesbased demand processes, such as autoregressive (AR), moving average(MA), autoregressive moving average(ARMA), and autoregressive with autoregressive conditional heteroskedasticity process(AR-ARCH). In an extensive computational study, we compare the performance of our model against the optimal policy obtained via stochastic dynamic programming. Our results demonstrate that the optimality gap of our approach averages 2.28% and that computational performance is good

Greenhouse gas emissions of waste management processes and options : a case study

Increasing concern about climate change is prompting organisations to mitigate their greenhouse gas emissions. Waste management activities also contribute to greenhouse gas emissions. In the waste management sector, there has been an increasing diversion of waste sent to landfill, with much emphasis on recycling and reuse to prevent emissions. This study evaluates the carbon footprint of the different processes involved in waste management systems, considering the entire waste management stream. Waste management data from the Royal Borough of Kingston upon Thames, London (UK), was used to estimate the carbon footprint for its (Royal Borough of Kingston upon Thames) current source segregation system. Second, modelled full and partial co-mingling scenarios were used to estimate carbon emissions from these proposed waste management approaches. The greenhouse gas emissions from the entire waste management system at Royal Borough of Kingston upon Thames were 12,347 t CO2e for the source-segregated scenario, and 11,907 t CO2e for the partial co-mingled model. These emissions amount to 203.26 kg CO2e t(-1) and 196.02 kg CO2e t(-1) municipal solid waste for source-segregated and partial co-mingled, respectively. The change from a source segregation fleet to a partial co-mingling fleet reduced the emissions, at least partly owing to a change in the number and type of vehicles

Cultural variability and consistency in adolescents’ emotional regulation and relationship with their parents: data from Argentina, Ghana, India and Zambia

The aim of the current study was to examine the relationship between parent?child relationship and emotional regulation in adolescents across four countries regarding: (a) mother?child relationship; (b) father?child relationship; (c) adolescents? emotion regulation; and (d) the relationship between mother?child/father?child close relationships and adolescents? emotion regulation. Sex differences were also considered in the analysis. The sample of 270 Zambian, 216 Argentinian, 200 Ghanaian, and 180 Indian adolescents answered The Experience in Close Relationship Questionnaire and the Emotional Regulation Questionnaire. Results revealed cultural differences in the way adolescents perceived their relations with parents. Zambian adolescents were more likely to perceive their relationship as avoidant compared to Ghanaian, Argentina and Indian. Consistent with literature, Zambian and Argentinian adolescents who perceived their parents as avoidant were likely to use less cognitive appraisal as an emotion regulation strategy. Finally, Argentinian adolescents who used expressive suppression were also likely to perceive their parents as avoidant.Fil: Hapunda, Given. University of Zambia; ZambiaFil: Mahama, S.. University of Ghana; GhanaFil: Mesurado, Maria Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro Interdisciplinario de Investigaciones en Psicología Matemática y Experimental Dr. Horacio J. A. Rimoldi; ArgentinaFil: Verma, S.K.. University of Delhi; IndiaFil: Koller, S.. North-West University; Sudáfrica. Universidade Federal do Rio Grande do Sul; Brasi

Counseling Challenges in the New Normal : Inputs for Quality Guidance and Counseling Program

With no face-to-face classes until a vaccine is available, schools have to adjust and learning must continue in different modalities. In the Philippines, online learning delivery is the primary mode of learning with many private schools adapting it. Learning continuity plan was created and the Department of Education set the most essential learning competencies for school year 2020-2021. Since education is a holistic approach, the mental and emotional well-being of the students must also be given significant attention. Counseling, a strong support in the welfare of the students, is needed to address the different concerns of the students. However, guidance counselors see a lot of challenges in providing counseling to students in an online environment. They have doubts in being truly present with the students. Potential mental and emotional health issues have been identified and preparations were made that will make the guidance and counseling services more felt and reliable despite being in an online modality. This study aims to find out the challenges that the guidance counselors encountered in providing counseling service to students. It also aims to identify the issues and concerns experienced by the students in online learning and the interventions provided by the guidance counselors in handling them. It found out that mental health issues, feeling of isolation, voluminous requirements and unstable internet connection were the concerns of the students. In addressing them, they provided individual and group counseling, communicated with the parents, collaborated more closely with the class advisers, teachers, and academic heads, strengthened the homeroom and guidance period, and held mental health activities. From the experiences, their realizations and new gained insights will be used as bases in enhancing the guidance and counseling program for school year 2021-2022

Computing non-stationary (s,S) policies using mixed integer linear programming

This paper addresses the single-item single-stocking location stochastic lot sizing problem under the $(s, S)$ policy. We first present a mixed integer non-linear programming (MINLP) formulation for determining near-optimal $(s, S)$ policy parameters. To tackle larger instances, we then combine the previously introduced MINLP model and a binary search approach. These models can be reformulated as mixed integer linear programming (MILP) models which can be easily implemented and solved by using off-the-shelf optimisation software. Computational experiments demonstrate that optimality gaps of these models are around $0.3\%$ of the optimal policy cost and computational times are reasonable

Assessment of PM10 and heavy metal concentration in a ceramic cluster (NE Spain) and the influence on nearby soils

Environmental pollution control is one of the most important goals in pollution risk assessment today. The aim of this study is to conduct a retrospective view of the evolution of matter particulate (PM10) and the heavy metals (Cd, Ni and Pb) at different localities (Alcora, Castellón and Onda) in the Spanish cluster ceramic in a period between January 2007 and December 2011. The study area is in the province of Castellón. This province is a strategic area in the framework of European Union Pollution control. Approximately 80% of European ceramic tiles and ceramic frits manufacturers are concentrated in two areas, forming the so-called "ceramic clusters"; one is in Modena (Italy) and the other in Castellón (Spain). In these kind of areas, there are a lot of pollutants from this industry that represent an important contribution to soil contamination so it is necessary to control their air quality. In these areas atmospheric particles are deposited in the ground through both dry and wet deposition. Soil is a major sink for heavy metals released into the environment. For this purpose the levels of PM10 in ambient air and the corresponding annual and seasonal trend were calculated. The results of the study show that the PM10 and heavy metal concentrations are below the limit values recommended by European Union Legislation for the protection of human health and ecosystems in the study period. There is an important reduction of them from 2009 in all control stations due to economic crisis and subsequent decrease of industrial activity. The atmospheric seasonal tendency of pollutant concentrations is marked by the rate of industrial activity and additionally by the temperature. Complementarily, a comparative study of heavy metal levels in soils was performed in this area. Soils with low pollution by Ni and Pb were detected, while different pollution by Cd was found depending on the sampling site. Although there is an evident reduction of PM10 and heavy metal levels, the results show that these pollut

Métodos de plano crítico para el análisis de fatiga multiaxial en el acero inoxidable 316

El presente trabajo estudia la capacidad de predicción de los modelos de plano crítico para casos de fatiga multiaxial. El material que se estudia es un acero inoxidable 316. Los caminos de carga aplicados son uniaxiales y biaxiales en la superficie de la probeta. El siguiente estudio realiza una comparativa de las predicciones de vida a fatiga y ángulo de grieta de los modelo Wang-Brown, Fatemi-Socie, Liu I y Liu II. Se observó que la mejor predicción de vida fue devuelta por el modelo de Liu II y para el ángulo de grieta por Liu I.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Los autores agradecen la financiación aportada para la realización de este trabajo al Ministerio de Economía y Competitividad (referencia MAT2016-76951-C2-2-P)

Determinación experimental de la carga de apertura de grieta en fatiga bajo cargas aleatorias

El concepto de carga de apertura o cierre de grieta es ampliamente utilizado en fatiga para justificar el comportamiento del crecimiento de grietas con distintas relaciones de carga y el efecto de interacción de las cargas. Hasta la fecha son numerosas las técnicas experimentales propuestas para medir la apertura de grieta y entre ellas los métodos de flexibilidad son ampliamente utilizados por su simplicidad. En este trabajo se propone una modificación del método propuesto por la ASTM y se presentan los resultados obtenidos en ensayos de crecimiento de grietas por fatiga bajo cargas aleatorias. Así mismo, los valores experimentales de cargas de apertura son comparados con los calculados analíticamente por un modelo de simulación tipo “strip-yield” implementado en el software NASGRO. En general, se ha encontrado una concordancia razonablemente buena entre los valores experimentales y los obtenidos por simulación.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Los autores agradecen la financiación aportada para la realización de este trabajo al Ministerio de Economía y Competitividad (referencia MAT2016-76951-C2-2-P)

Differential Contribution of Subunit Interfaces to α 9 α 10 Nicotinic Acetylcholine Receptor Function

Nicotinic acetylcholine receptors can be assembled from either homomeric or heteromeric pentameric subunit combinations. At the interface of the extracellular domains of adjacent subunits lies the acetylcholine binding site, composed of a principal component provided by one subunit and a complementary component of the adjacent subunit. Compared with neuronal nicotinic acetylcholine cholinergic receptors (nAChRs) assembled from α and β subunits, the α9α10 receptor is an atypical member of the family. It is a heteromeric receptor composed only of α subunits. Whereas mammalian α9 subunits can form functional homomeric α9 receptors, α10 subunits do not generate functional channels when expressed heterologously. Hence, it has been proposed that α10 might serve as a structural subunit, much like a β subunit of heteromeric nAChRs, providing only complementary components to the agonist binding site. Here, we have made use of site-directed mutagenesis to examine the contribution of subunit interface domains to α9α10 receptors by a combination of electrophysiological and radioligand binding studies. Characterization of receptors containing Y190T mutations revealed unexpectedly that both α9 and α10 subunits equally contribute to the principal components of the α9α10 nAChR. In addition, we have shown that the introduction of a W55T mutation impairs receptor binding and function in the rat α9 subunit but not in the α10 subunit, indicating that the contribution of α9 and α10 subunits to complementary components of the ligand-binding site is nonequivalent. We conclude that this asymmetry, which is supported by molecular docking studies, results from adaptive amino acid changes acquired only during the evolution of mammalian α10 subunits.Fil: Boffi, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Marcovich, Irina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Gill Thind, JasKiran K.. University College London; Reino UnidoFil: Corradi, Jeremias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Collins, Toby. University College London; Reino UnidoFil: Lipovsek, Maria Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Moglie, Marcelo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Plazas, Paola Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Craig, Patricio Oliver. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Millar, Neil S.. University College London; Reino UnidoFil: Bouzat, Cecilia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin