Process planning optimization is a well-known NP-hard combinatorial problem extensively studied in the scientific community. Its main components include operation sequencing, selection of manufacturing resources and determination of appropriate setup plans. These problems require metaheuristic-based approaches in order to be effectively and efficiently solved. Therefore, to optimize the complex process planning problem, a novel hybrid grey wolf optimizer (HGWO) is proposed. The traditional grey wolf optimizer (GWO) is improved by employing genetic strategies such as selection, crossover and mutation which enhance global search abilities and convergence of the traditional GWO. Precedence relationships among machining operations are taken into account and precedence constraints are modeled using operation precedence graphs and adjacency matrices. Constraint handling heuristic procedure is adopted to move infeasible solutions to a feasible domain. Minimization of the total weighted machining cost of a process plan is adopted as the objective and three experimental studies that consider three different prismatic parts are conducted. Comparative analysis of the obtained cost values, as well as the convergence analysis, are performed and the HGWO approach demonstrated effectiveness and flexibility in finding optimal and near-optimal process plans. On the other side, comparative analysis of computational times and execution times of certain MATLAB functions showed that the HGWO have good time efficiency but limited since it requires more time compared to considered hybrid and traditional algorithms. Potential directions to improving efficiency and performances of the proposed approach are given in conclusions.

• Keywords
• constraint handling, crossover, grey wolf optimizer, mutation, precedence constraints, process planning optimization, selection,
• Publication type
• Journal Article MeSH

We introduce a novel framework for conceptualising, quantifying and unifying discordant patterns of species richness along geographical gradients. While not itself explicitly mechanistic, this approach offers a path towards understanding mechanisms. In this study, we focused on the diverse patterns of species richness on mountainsides. We conjectured that elevational range midpoints of species may be drawn towards a single midpoint attractor - a unimodal gradient of environmental favourability. The midpoint attractor interacts with geometric constraints imposed by sea level and the mountaintop to produce taxon-specific patterns of species richness. We developed a Bayesian simulation model to estimate the location and strength of the midpoint attractor from species occurrence data sampled along mountainsides. We also constructed midpoint predictor models to test whether environmental variables could directly account for the observed patterns of species range midpoints. We challenged these models with 16 elevational data sets, comprising 4500 species of insects, vertebrates and plants. The midpoint predictor models generally failed to predict the pattern of species midpoints. In contrast, the midpoint attractor model closely reproduced empirical spatial patterns of species richness and range midpoints. Gradients of environmental favourability, subject to geometric constraints, may parsimoniously account for elevational and other patterns of species richness.

• Keywords
• Bayesian model, Biogeography, elevational gradients, geometric constraints, mid-domain effect, midpoint predictor model, stochastic model, truncated niche,
• MeSH
• Bayes Theorem MeSH
• Biodiversity * MeSH
• Models, Biological * MeSH
• Ecosystem * MeSH
• Plant Physiological Phenomena MeSH
• Insecta physiology   MeSH
• Vertebrates physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

PURPOSE: For unbiased comparison of different radiation modalities and techniques, consensus on delineation of radiation sensitive organs at risk (OARs) and on their dose constraints is warranted. Following the publication of a digital, online atlas for OAR delineation in neuro-oncology by the same group, we assessed the brain OAR-dose constraints in a follow-up study. METHODS: We performed a comprehensive search to identify the current papers on OAR dose constraints for normofractionated photon and particle therapy in PubMed, Ovid Medline, Cochrane Library, Embase and Web of Science. Moreover, the included articles' reference lists were cross-checked for potential studies that met the inclusion criteria. Consensus was reached among 20 radiation oncology experts in the field of neuro-oncology. RESULTS: For the OARs published in the neuro-oncology literature, we summarized the available literature and recommended dose constraints associated with certain levels of normal tissue complication probability (NTCP) according to the recent ICRU recommendations. For those OARs with lacking or insufficient NTCP data, a proposal for effective and efficient data collection is given. CONCLUSION: The use of the European Particle Therapy Network-consensus OAR dose constraints summarized in this article is recommended for the model-based approach comparing photon and proton beam irradiation as well as for prospective clinical trials including novel radiation techniques and/or modalities.

• Keywords
• Dose constraints, European Particle Therapy Network, Organs at risk, Particle therapy,
• MeSH
• Radiotherapy Dosage * MeSH
• Consensus MeSH
• Organs at Risk * radiation effects   MeSH
• Humans MeSH
• Brain Neoplasms radiotherapy   MeSH
• Radiotherapy Planning, Computer-Assisted methods   MeSH
• Proton Therapy adverse effects   MeSH
• Heavy Ion Radiotherapy adverse effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

OBJECTIVES: Excessive internet use (EIU) has been studied predominantly within the context of individual risk factors. Less attention has been paid to social factors, especially in a fashion complex enough to include the multiple domains of adolescent socialization. This study examined the relationship between EIU and constraints within family, school, peer groups, and neighbourhoods, while controlling for emotional and behavioural difficulties. METHODS: This study was based on survey data from the Health Behaviour in School-aged Children study, which was conducted in Slovakia in 2018. The sample of representative adolescents totalled 8400 (mean age: 13.44 years; SDage = 1.33; 50.9% boys). RESULTS: Multiple-step linear regression revealed that, after controlling for sociodemographic factors and emotional and behavioural difficulties, peer problems had the least effect, while the constraints related to family and neighbourhood stood out as especially problematic. Combined variables explained 20% variance of EIU. CONCLUSIONS: Social constraints proved to be important factors in adolescent EIU. The important role of a problematic neighbourhood is a novel finding and suggests that it should be targeted in prevention.

• Keywords
• Adolescents, Excessive internet use, Internet addiction, Problematic neighbourhood, Social constraints,
• MeSH
• Residence Characteristics * MeSH
• Adolescent Behavior psychology   MeSH
• Child MeSH
• Adult MeSH
• Humans MeSH
• Adolescent MeSH
• Internet Use statistics & numerical data   MeSH
• Surveys and Questionnaires MeSH
• Family Relations psychology   MeSH
• Schools * MeSH
• Social Isolation psychology   MeSH
• Peer Group MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Slovakia MeSH

The sustainable production and use of small-scale biogas energy are required to ensure clean household energy access in developing countries, including the Sub-Saharan Africa (SSA) region. This is influenced by market risks, which can be identified as political, economic, social, technical, legal, and environmental (PESTLE). This study examines peer-reviewed and grey literature for the period from 2000 to 2020 to identify the PESTLE constraints and assess their impact on the sustainable development of the technology in the SSA region. The production of biogas with small-scale plants is commonly done by rural and peri-urban households. Results show that economic constraints are the most dominant and reducing at a slow pace. This is followed by political constraints, which have received much attention in the last two decades. Despite the policy improvements, broader national bioenergy policies and interventions are still to make significant gains, especially in the Central African region. In order of significance, the Southern, East, and West Africa regions have made greater progress in reducing the constraints. To achieve the sustainable development of the technology, there is a need to further address the PESTLE constraints at national and regional levels. This study partly deduces that the unsustainable production, use, and inadequate regulation of the small-scale biogas sector are delaying its transition in the SSA region.

• Keywords
• Anaerobic digestion, Bioenergy policy, Developing countries, Energy access, PESTLE constraints, Sustainable development,
• MeSH
• Biofuels * MeSH
• Family Characteristics MeSH
• Humans MeSH
• Technology MeSH
• Sustainable Development * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Systematic Review MeSH
• Geographicals
• Africa South of the Sahara MeSH
• Names of Substances
• Biofuels * MeSH

Thermodynamic fluxes (diffusion fluxes, heat flux, etc.) are often proportional to thermodynamic forces (gradients of chemical potentials, temperature, etc.) via the matrix of phenomenological coefficients. Onsager's relations imply that the matrix is symmetric, which reduces the number of unknown coefficients is reduced. In this article we demonstrate that for a class of nonequilibrium thermodynamic models in addition to Onsager's relations the phenomenological coefficients must share the same functional dependence on the local thermodynamic state variables. Thermodynamic models and experimental data should be validated through consistency with the functional constraint. We present examples of coupled heat and mass transport (thermodiffusion) and coupled charge and mass transport (electro-osmotic drag). Additionally, these newly identified constraints further reduce the number of experiments needed to describe the phenomenological coefficient.

• Publication type
• Journal Article MeSH

Task and environment-related constraints can influence spike performance in volleyball players. This study was designated to investigate the impact of awareness of the presence or absence of a defensive block by the opponents on the performance and coordination pattern of spikes in elite volleyball attackers. Simulating a real-game scenario, 10 elite youth attackers (aged 15.5 ± 0.7 years) executed six spikes each with prior notification about the presence/absence of defences and six spikes without any notification. In each condition, they were blocked by two opponents in three trials. The coordination patterning of the attackers was explored using cluster analysis based on a Self-Organising Map (SOM). The SOMs and the cluster analysis showed that the coordination pattern of the spike execution was very individual-specific; however, in the third layer of the cluster analysis, it was revealed that the movement pattern of spike execution had similarities in the scenario wherein the players had prior awareness of the defences. Providing the attackers with information on the opponents' condition or performance could shift the attackers' focus from a game-oriented condition to the rivals' behaviour, which consequently resulted in deterioration of their spike performance.

• Keywords
• Movement coordination, SOM, best matching unit trajectory, task-related constraints, volleyball,
• MeSH
• Biomechanical Phenomena MeSH
• Humans MeSH
• Adolescent MeSH
• Athletic Performance * MeSH
• Volleyball * MeSH
• Check Tag
• Humans MeSH
• Adolescent MeSH
• Publication type
• Journal Article MeSH

Intracellular and extracellular mechanical forces play a crucial role during tissue growth, modulating nuclear shape and function and resulting in complex collective cell behaviour. However, the mechanistic understanding of how the orientation, shape, symmetry and homogeneity of cells are affected by environmental geometry is still lacking. Here we investigate cooperative cell behaviour and patterns under geometric constraints created by topographically patterned substrates. We show how cells cooperatively adopt their geometry, shape, positioning of the nucleus and subsequent proliferation activity. Our findings indicate that geometric constraints induce significant squeezing of cells and nuclei, cytoskeleton reorganization, drastic condensation of chromatin resulting in a change in the cell proliferation rate and the anisotropic growth of cultures. Altogether, this work not only demonstrates complex non-trivial collective cellular responses to geometrical constraints but also provides a tentative explanation of the observed cell culture patterns grown on different topographically patterned substrates. These findings provide important fundamental knowledge, which could serve as a basis for better controlled tissue growth and cell-engineering applications.

• MeSH
• Models, Biological * MeSH
• Cell Nucleus physiology   ultrastructure   MeSH
• Mechanotransduction, Cellular physiology   MeSH
• Hep G2 Cells MeSH
• Humans MeSH
• Cell Communication physiology   MeSH
• Computer Simulation MeSH
• Cell Proliferation physiology   MeSH
• Cell Size * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

We propose helioseismology as a new, precision probe of fifth forces at astrophysical scales, and apply it on the most general scalar-tensor theories for dark energy, known as degenerate higher-order scalar-tensor theories. We explain how the effect of the fifth force on the solar interior leaves an observable imprint on the acoustic oscillations, and under certain assumptions we numerically compute the nonradial pulsation eigenfrequencies within modified gravity. We illustrate its constraining power by showing that helioseismic observations have the potential to improve constraints on the strength of the fifth force by more than 2 orders of magnitude, as -1.8×10^{-3}≤Y≤1.2×10^{-3} (at 2σ). This in turn would suggest constraints of similar order for the theory's free functions around a cosmological background (α_{H}, β_{1}).

• Publication type
• Journal Article MeSH

Specific pollen placement by zygomorphic flowers on pollinators is one of the key innovations of angiosperm evolution [1]. In most phylogenetic lineages that have evolved zygomorphic flowers, reproductive organs are positioned either in the lower or upper part of the flower. Although these specific positions largely enhance pollen economy, they also represent architectural constraints such that flowers are able to place pollen only on the dorsal or ventral part of pollinators' bodies [2]. Such constraints can lead to interspecific pollen placement in situations where phylogenetically related species with the same floral architecture share pollinators [3].

• MeSH
• Biological Evolution MeSH
• Impatiens physiology   MeSH
• Pollination * MeSH
• Feeding Behavior * MeSH
• Songbirds physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Letter MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Cameroon MeSH