Entropy of continuous maps on quasi-metric spaces

The category of metric spaces is a subcategory of quasi-metric spaces. In this paper the notion of entropy for the continuous maps of a quasi-metric space is extended via spanning and separated sets. Moreover, two metric spaces that are associated to a given quasi-metric space are introduced and the entropy of a map of a given quasi-metric space and the maps of its associated metric spaces are compared. It is shown that the entropy of a map when symmetric properties is included is grater or equal to the entropy in the case that the symmetric property of the space is not considered

Distal Fuzzy Dynamical Systems

In this paper the t-distal notion is extended for fuzzy dynamical systems on fuzzy metric spaces. A method for constructing fuzzy metric spaces is studied. The product of t-distal fuzzy dynamical systems is considered. It is proved that: a product of fuzzy dynamical systems is t- distal if and only if its components are t-distal. The persistence of the t-distal property up to a fuzzy factor map is proved

Analysis of the commutation error of filtering operators for the double-averaged equations of flows in porous media in a LES formalism

The continuum approach employing porous media models is an attractive solution method in the area of Computational Fluid Dynamics (CFD) simulation of fixed-bed reactors due to its robustness and efficiency. This paper applies the double-averaging methodology to refine the mathematical basis for the continuum approach, opening a way to alleviate its main limitations: space-invariant averaging volume and inaccurate treatment of the porous/non-porous interface. The averaging operator is recast as a general space-time filter and a detailed analysis of commutation errors is performed, using a classic Large Eddy Simulation (LES) formalism. An explicit filtering framework has been implemented in the open-source CFD library OpenFOAM to carry out an a-posteriori evaluation of the unclosed terms appearing in the Double-Averaged Navier-Stokes (DANS) equations also considering a space-varying filter width. Two resolved simulations have been performed. First, the flow around a single, stationary particle has been considered and used to validate derived equations and the filtering procedure. Second, an LES of the turbulent flow in a channel partly occupied with a porous medium has been conducted. The results have been filtered, and the commutation error at the porous-fluid interface has been evaluated and compared to the prediction of two models. The significance of the commutation error terms is also discussed and assessed. Finally, the solver for DANS equations has been developed and used to simulate both of the studied geometries. The magnitude of the error associated with neglecting the commutation errors has been investigated and an LES simulation combined with a porous drag model was performed. Very encouraging results have been obtained indicating that the inaccuracy of the drag closure overshadows the error related to the commutation of operators.Comment: This material has been submitted to Physics of Fluids. It contains 33 pages and 21 Figure

Factors Affecting Hemodialysis Patients' Satisfaction with Their Dialysis Therapy

Aim. To assess the degree of satisfaction among hemodialysis patients and the factors influencing this satisfaction. Methods. Patients were recruited from 3 Saudi dialysis centers. Demographic data was collected. Using 1 to 10 Likert scale, the patients were asked to rate the overall satisfaction with, and the overall impact of, their dialysis therapy on their lives and to rate the effect of the dialysis therapy on 15 qualities of life domains. Results. 322 patients were recruited (72.6% of the total eligible patients). The mean age was 51.7 years (±15.4); 58% have been on dialysis for >3 years. The mean Charlson Comorbidity Index was 3.2 (±2), and Kt/V was 1.3 (±0.44). The mean satisfaction score was (7.41 ± 2.75) and the mean score of the impact of the dialysis on the patients' lives was 5.32 ± 2.55. Male patients reported worse effect of dialysis on family life, social life, energy, and appetite. Longer period since the commencement of dialysis was associated with adverse effect on finances and energy. Lower level of education was associated with worse dialysis effect on stress, overall health, sexual life, hobbies, and exercise ability. Conclusion. The level of satisfaction is affected by gender, duration on dialysis, educational level, and standard of care given

Salicylic acid improves salinity-alkalinity tolerance in pepper (Capsicum annuum L.)

Salinization and alkalization of soils are agricultural problems in arid and semiarid regions of the world such as Iran. In this experiment the effects of salicylic acid (SA) on resistance of pepper plants under salt stress (SS) and alkali stress (AS) were evaluated. Treatments include 0 and 150 mM of SS, 0, 50 and 100 mM of AS and 0, 0.75 and 1.5 mM SA. Results showed that SS and AS imposed negative effects on pepper plant growth and productivity. Reduction in growth and yield in SS was higher than AS and maximum reduction occurred in high mixed stresses. SA application improved growth parameters and increased yield, relative water content (RWC) and chlorophyll of plants subjected to SS and AS and provided significant protection against stress compared to non-SA-treated plants.  For most traits, 0.75 mM of SA was more effective than 1.5 mM concentration. SA ameliorated the injury caused by SS and AS by increasing chlorophyll and RWC and inhibiting proline accumulation and leaf electrolyte leakage (EL). In general, results indicate that salinity and alkalinity have negative effects on growth and yield of pepper plants and these negative effects can be ameliorated by application of SA

Gastrointestinal manifestations and dynamics of liver enzymes in children and adolescents with COVID-19 infection: A systematic review and meta-analysis

Objectives: To improve the knowledge on Coronavirus Disease (COVID-19) infection, we aimed to study the prevalence of gastrointestinal symptoms and the dynamics of liver enzymes in children infected with COVID-19. Methods: We performed a systematic search of all the articles published up to May 2020 in the following databases: PubMed-MEDLINE, Scopus, and Cochrane. We chose the fixed-or random-effect model for analysis based on the I2 statistic. The included data were analyzed to identify the prevalence of gastrointestinal symptoms (diarrhea, vomiting or nausea) and to identify the dynamics of liver enzymes in children and adolescents diagnosed with COVID-19. Results: We detected an overall prevalence of all gastrointestinal symptoms of 26 (95 CI: 0.18-0.35). The pooled prevalence of diarrhea and nausea/vomiting was 12 (95 CI: 0.08-0.16) with no heterogeneity (P = 0.19; I2 = 23.53) and 11 (95 CI: 0.05-0.17), respectively. The pooled prevalence of elevated ALT and AST and LDH was 12 (95 CI: 0.07-0.17), 14 (95 CI: 0.10-0.18) and 33 (95 CI: 0.12-0.54), respectively among the included studies. Conclusions: According to our systematic review and meta-analysis, 26 of the children and adolescents diagnosed with COVID-19 present gastrointestinal symptoms. This paper has provided a comprehensive overview of the prevalence of digestive symptoms of COVID-19 and of the liver enzymes dynamics in children and adolescents. © 2020, Author(s)

Evaluation of Plant Nitrogen Use Efficiency in Different Crop Rotations

IntroductionThere is an urgent need to increase per capita food production to compete with high population growth while maintaining environmental sustainability. Because nitrogen plays a vital role in food production for humans and livestock, nitrogen management is essential in food production. In most cropping systems, nitrogen management seems to be a major challenge due to its high mobility and natural tendency for losses from the soil-plant system to the environment. Soil organic carbon plays a key role in improving soil ecological conditions. Adding organic matter to the soil is an excellent tool for improving physical, chemical and biological conditions and is almost always desirable. Soil organic carbon stock of crop ecosystems may be increased by improving farming practices. The application of green manure, fertilizer and the return of crop straw into the soil are known as management operations to increase soil organic carbon. Fertilizers, especially nitrogen, increase crop yield, and organic carbon is returned to the soil through roots and debris, which in most cases leads to increased soil organic carbon.Materials and MethodsThis study was conducted with the aim of utilizing a set of improving farming practices in diverse cropping systems to improve nitrogen efficiency during two crop years. Farming practices including removal of summer fallow were used by importing three crops of mung bean, corn and wild rocket in rotation plus nitrogen supply levels factor. The crop rotation factor was applied in four levels of Fallow-wheat, mung bean-wheat, corn-wheat and wild rocket-wheat and the factor of nitrogen fertilizer (0, 180 and 360 kg.ha-1) in a randomized complete block design as factorial. Soil mineral nitrogen (nitrate and ammonium) were measured before sowing wheat and grain, straw and total plant nitrogen after harvest. Uptake efficiency, utilization efficiency, agronomic efficiency and nitrogen harvest index were calculated.Results and DiscussionThe results of combined analysis of variance showed that the crop rotation and nitrogen were significantly effective (ρ ≤ 0.01) on plant nitrogen, harvest index and nitrogen efficiency. Increasing nitrogen fertilizer up to 360 kg.ha-1 increased grain nitrogen, straw nitrogen, total plant nitrogen and also nitrogen harvest index. While the best uptake, utilization and agronomic efficiency of nitrogen was observed on the treatment without nitrogen fertilizer. Comparison of the means showed that the wild rocket-wheat crop rotation had the best result among all measured traits except utilization efficiency, while the utilization efficiency in the corn-wheat crop rotation showed the best performance. The results clearly show the effect of increasing organic carbon on nitrogen availability and grain nitrogen concentration as well as the role of cover crops and legume, in increasing access to nitrogen. The amount of grain nitrogen was directly affected by the amount of nitrogen fertilizer. The highest correlation coefficient was seen between agronomic and uptake efficiency (r = 0.96**). There was also a significant inverse relationship between nitrogen harvest index and the types of calculated efficiencies. The amount of uptake efficiency and agronomic efficiency in all crop rotations except corn-wheat in the second year improved compared to the first year. The highest increase in efficiency in the second year was related to the wild rocket-wheat crop rotation. In the conditions of 360 and 180 kg.ha-1 nitrogen fertilizer, the nitrogen harvest index increased in the second year compared to the first year. While in conditions without nitrogen fertilizer, nitrogen harvest index has a significant decrease. Therefore, at least in the short term, to increase the nitrogen harvest index, the minimum supply of nitrogen fertilizer should be used, even under improving crop management conditions such as green manure, removal of fallow and introduction of legumes in rotation and return of crop residues.ConclusionContinuous cropping, removal of fallow, use of cover crops and legume and preservation of residues led to increased carbon and nitrogen sequestration in soil and consequently increase biomass and nitrogen concentration in plant tissue. On the other hand, crop rotations that increased soil organic carbon and improved soil fertility quickly improved nitrogen efficiency and nitrogen harvest index

A Proposed Role for Pro-Inflammatory Cytokines in Damaging Behavior in Pigs

Sickness can change our mood for the worse, leaving us sad, lethargic, grumpy and less socially inclined. This mood change is part of a set of behavioral symptoms called sickness behavior and has features in common with core symptoms of depression. Therefore, the physiological changes induced by immune activation, for example following infection, are in the spotlight for explaining mechanisms behind mental health challenges such as depression. While humans may take a day off and isolate themselves until they feel better, farm animals housed in groups have only limited possibilities for social withdrawal. We suggest that immune activation could be a major factor influencing social interactions in pigs, with outbreaks of damaging behavior such as tail biting as a possible result. The hypothesis presented here is that the effects of several known risk factors for tail biting are mediated by pro-inflammatory cytokines, proteins produced by the immune system, and their effect on neurotransmitter systems. We describe the background for and implications of this hypothesis.Peer reviewe