Note on the Persistence of a Nonautonomous Lotka-Volterra Competitive System with Infinite Delay and Feedback Controls

We study a nonautonomous Lotka-Volterra competitive system with infinite delay and feedback controls. We establish a series of criteria under which a part of n-species of the systems is driven to extinction while the remaining part of the species is persistent. Particularly, as a special case, a series of new sufficient conditions on the persistence for all species of system are obtained. Several examples together with their numerical simulations show the feasibility of our main results

Personal Best Cuckoo Search Algorithm for Global Optimization

Real-life optimization problems demand robust algorithms that perform efficient search in the environment without trapping in local optimal locations. Such algorithms are equipped with balanced explorative and exploitative capabilities. Cuckoo search (CS) algorithm is also one of such optimization algorithms, which is inspired from nature. Despite effective search strategies using Lévy flights and solution switching approach, CS suffers from lack of population diversity when implemented in hard optimization problems. In this paper, enhanced local and global search strategies have been proposed in CS algorithm. The proposed variant employs personal best information in solution generation process, hence called Personal Best Cuckoo Search (pBestCS). Moreover, instead of constant value for switching parameter, pBestCS dynamically updates switching parameter as the iterations proceed. The prior approach enhances local search ability, whereas the later modification enforces effective global search ability in the algorithm. The experimental results on both unimodal and multimodal test functions with different dimensionalities validated the efficiency of the proposed modification. Based on comprehensive statistical analysis and comparisons, pBestCS outperformed the standard CS algorithm, as well as, other popular swarm-based metaheuristic algorithms particle swarm optimization (PSO) and artificial bee colony (ABC)

Solubility behavior and thermodynamic modeling of inosine (form β) in four cosolvency systems at T = 278.15 to 323.15 K

N,N-Dimethylformamide (DMF) as the main solvent with strong dissolving power was blended with four secondary solvents (ethanol, n-propanol, isopropanol, and propylene glycol) with relatively weak dissolving power to form many new solvents. The dispersion index (inosine (form β) mole fraction) in five organic solvents such as DMF and in the newly formed solvent was also obtained one by one with the static method commonly used in solid–liquid equilibrium. The temperature environment includes the high temperature set at 323.15 K, the low temperature set at 278.15 K, and an interval between each temperature of 5 K. The pressure environment was the atmospheric pressure in the natural state, and the usual value was 101.0 kPa. In a mixed system, temperature was a non-negligible influencing factor from beginning to end, and its increase often led the solute to the trend of high solubility. In addition, the proportion of the main solvent also dominated the solubilization trend of the inosine (form β); the larger the proportion of DMF, the easier the dissolution process. When both of the above factors were fixed at a certain point, the dispersing ability of the dispersing liquid composed of DMF and ethanol was undoubtedly the first. Three models (Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, and modified Apelblat–Jouyban–Acree model) were used to correlate the solubility data. The largest relative average deviation and root-mean-square deviation values were 4.66 × 10–2 and 7.27 × 10–4, respectively. The dispersion data of inosine (form β) obtained through this experimental process and related thermodynamic parameters obtained through thermodynamic calculations have important application significance for its industrial production and further purification

A dataset of low-carbon energy transition index for Chinese cities 2003–2019

Cities are at the heart of climate change mitigation as they account for over 70% of global carbon emissions. However, cities vary in their energy systems and socioeconomic capacities to transition to renewable energy. To address this heterogeneity, this study proposes an Energy Transition Index (ETI) specifically designed for cities, and applies it to track the progress of energy transition in Chinese cities. The city-level ETI framework is based on the national ETI developed by the World Economic Forum (WEF) and comprises two sub-indexes: the Energy System Performance sub-index, which evaluates the current status of cities’ energy systems in terms of energy transition, and the Transition Readiness sub-index, which assesses their socioeconomic capacity for future energy transition. The initial version of the dataset includes ETI and its sub-indexes for 282 Chinese cities from 2003 to 2019, with annual updates planned. The spatiotemporal data provided by the dataset facilitates research into the energy transition roadmap for different cities, which can help China achieve its energy transition goals

Experimental determination and thermodynamic correlation of 7-amino-4-methylcoumarin solubility in various cosolvency mixtures at (278.15–323.15) K

Four solvents (ethanol, isopropanol, ethylene glycol (EG), and N,N-dimethylformamide (DMF)) that can be mixed with water in any ratio were selected to determine the dissolution performance of 7-amino-4-methylcoumarin by the classical shake-flask method. The measured temperature range began at 278.15 K and ended at 303.15 K, and the pressure environment was controlled at standard atmospheric pressure (101.1 kPa). Results reveal that with the addition of organic solvents, the solubilization effect of 7-amino-4-methylcoumarin was very significant and the larger the amount of addition, the more obvious was the effect of solubilization. Not only that, the temperature change had a non-negligible effect on the dispersion of 7-amino-4-methylcoumarin; the temperature increased monotonically, and the better was the dissolution. When the external conditions were kept constant, the addition of DMF made the solubilization effect of 7-amino-4-methylcoumarin most obvious among all organic solvents used. This study involved three models, including the Jouyban–Acree model and its two variants (van’t Hoff–Jouyban–Acree model and Apelblat–Jouyban–Acree model), which were used to correlate the solubility data of 7-amino-4-methylcoumarin in aqueous cosolvent mixtures. The relative average deviation (RAD) and root-mean-square deviation (RMSD) reaches to 3.47 × 10–2 and 1.79 × 10–3 rooting in the van’t Hoff–Jouyban–Acree model. The relevant parameters obtained through model calculation and experimental means are essential for product synthesis, separation, and purification processes

Dynamic characteristics and drivers of the regional household energy-carbon-water nexus in China

Being a node of the energy-water consumer and carbon dioxide (CO2) emitter, the household is one key sector to pilot integrated energy-carbon-water (ECW) management. This study developed an integrated framework to explore China’s provincial household ECW nexus as well as their drivers from the years 2000 through 2016. The absolute amount and growth rate of household energy use (HEU), household CO2 emissions (HCE), and household water use (HWU) were abstracted to reveal the dynamic characteristics of the household ECW nexus. Efficiency advance, income growth, urbanization, family size, and household number were defined to explain the changes in the household ECW nexus. This study revealed that there is a huge regional heterogeneity in China’s household ECW nexus. Developed regions such as Zhejiang, Jiangsu, Guangdong, and Shanghai are the most important household ECW nexus nodes with larger amounts and growth rates of household ECW. Income growth overwhelmingly increases ECW, while efficiency advance effectively curbs its growth. Comparatively, household number, family size, and urbanization have small effects. Therefore, implementing differentiated management and focusing on the synergy of socioeconomic factors are the keys to achieving integrated household ECW management. And the analytical framework can be used to analyze ECW nexus from a sector, city, or country perspective

Review on City-Level Carbon Accounting

Carbon accounting results for the same city can differ due to differences in protocols, methods, and data sources. A critical review of these differences and the connection among them can help to bridge our knowledge between university-based researchers and protocol practitioners in accounting and taking further mitigation actions. The purpose of this study is to provide a review of published research and protocols related to city carbon accounting, paying attention to both their science and practical actions. To begin with, the most cited articles in this field are identified and analyzed by employing a citation network analysis to illustrate the development of city-level carbon accounting from three perspectives. We also reveal the relationship between research methods and accounting protocols. Furthermore, a timeline of relevant organizations, protocols, and projects is provided to demonstrate the applications of city carbon accounting in practice. The citation networks indicate that the field is dominated by pure-geographic production-based and community infrastructure-based accounting; however, emerging models that combine economic system analysis from a consumption-based perspective are leading to new trends in the field. The emissions accounted for by various research methods consist essentially of the scope 1–3, as defined in accounting protocols. The latest accounting protocols include consumption-based accounting, but most cities still limit their accounting and reporting from pure-geographic production-based and community infrastructure-based perspectives. In conclusion, we argue that protocol practitioners require support in conducting carbon accounting, so as to explore the potential in mitigation and adaptation from a number of perspectives. This should also be a priority for future studies

Single-cell functional analysis of parathyroid adenomas reveals distinct classes of calcium sensing behaviour in primary hyperparathyroidism

AbstractPrimary hyperparathyroidism (PHPT) is a common endocrine neoplastic disorder caused by a failure of calcium sensing secondary to tumour development in one or more of the parathyroid glands. Parathyroid adenomas are comprised of distinct cellular subpopulations of variable clonal status that exhibit differing degrees of calcium responsiveness. To gain a clearer understanding of the relationship among cellular identity, tumour composition and clinical biochemistry in PHPT, we developed a novel single cell platform for quantitative evaluation of calcium sensing behaviour in freshly resected human parathyroid tumour cells. Live‐cell intracellular calcium flux was visualized through Fluo‐4‐AM epifluorescence, followed by in situ immunofluorescence detection of the calcium sensing receptor (CASR), a central component in the extracellular calcium signalling pathway. The reactivity of individual parathyroid tumour cells to extracellular calcium stimulus was highly variable, with discrete kinetic response patterns observed both between and among parathyroid tumour samples. CASR abundance was not an obligate determinant of calcium responsiveness. Calcium EC50 values from a series of parathyroid adenomas revealed that the tumours segregated into two distinct categories. One group manifested a mean EC50 of 2.40 mM (95% CI: 2.37–2.41), closely aligned to the established normal range. The second group was less responsive to calcium stimulus, with a mean EC50 of 3.61 mM (95% CI: 3.45–3.95). This binary distribution indicates the existence of a previously unappreciated biochemical sub‐classification of PHPT tumours, possibly reflecting distinct etiological mechanisms. Recognition of quantitative differences in calcium sensing could have important implications for the clinical management of PHPT

Macroscopic helical chirality and self-motion of hierarchical self-assemblies induced by enantiomeric small molecules

Transfer of molecular chirality to supramolecular chirality at nanoscale and microscale by chemical self-assembly has been studied intensively for years. However, how such molecular chirality further transfers to the macroscale along the same path remains elusive. Here we reveal how the chirality from molecular level transfers to macroscopic level via self-assembly. We assemble a macrostripe using enantiomeric camphorsulfonic acid (CSA)-doped polyaniline with hierarchical order. The stripe can twist into a single-handed helical ribbon via helical self-motion. A multi-scale chemo-mechanical model is used to elucidate the mechanism underlying its chirality transfer and induction. The molecular origin of this macroscopic helical chirality is verified. Results provide a comprehensive understanding of hierarchical chirality transfer and helical motion in self-assembled materials and even their natural analogues. The stripe exhibits disparate actuation behaviour under stimuli of enantiomeric amines and integrating such chiral perception with helical self-motion may motivate chiral biomimetic studies of smart materials