Numerical resolution of moderately high-dimensional nonlinear PDEs remains a huge challenge due to the curse of dimensionality for the classical numerical methods including finite difference, finite element and spectral methods. Starting from the weak formulation of the Lawson-Euler scheme, this paper proposes a stochastic particle method (SPM) by tracking the deterministic motion, random jump, resampling and reweighting of particles. Real-valued weighted particles are adopted by SPM to approximate the high-dimensional solution, which automatically adjusts the point distribution to intimate the relevant feature of the solution. A piecewise constant reconstruction with virtual uniform grid is employed to evaluate the nonlinear terms, which fully exploits the intrinsic adaptive characteristic of SPM. Combining both, SPM can achieve the goal of adaptive sampling in time. Numerical experiments on the 6-D Allen-Cahn equation and the 7- D Hamiltonian-Jacobi-Bellman equation demonstrate the potential of SPM in solving moderately high-dimensional nonlinear PDEs efficiently while maintaining an acceptable accuracy
The proliferation and spread of antibiotic-resistant bacteria (ARB) significantly threaten human health and ecosystem. Periodate (PI) based advanced oxidation process has potentials for water purification but limited by complex activators or activation process. Herein, we demonstrated that H2O2 could be used to activate PI, achieving efficient ARB disinfection performance. Particularly, we found that the PI/H2O2 system (0.1 mM for both oxidants) could inactivate ARB (Escherichia coli) within 35 min. The intracellular defense system attacked by HO· radicals generated in the disinfection system, resulting in the inactivation of ARB. Antibiotic resistance genes (ARGs) released with the lysis of cell membrane could be further degraded by HO· radicals. Moreover, we found that the PI/H2O2 system was effective to inactivate ARB in a broad range of ionic strengths, with coexisting common ions and humic acid, as well as in four typical actual water bodies. The PI/H2O2 system could also efficiently disinfect other types of bacteria and degrade typical organic contaminants. In addition, under sunlight irradiation, the ARB inactivation performance of the PI/H2O2 system could be greatly improved. This study provided a practical and efficient way for decontaminating ARB/ARGs-polluted water.
Coastal sediment cores provide important records of land-based antibiotics' deposition. This study examined sediment cores from the Hangzhou Bay, East China Sea, dating back to 1980–2020 using 210Pbex. The 40-year analysis revealed a mismatch between sediment depth and age. Wastewater treatment facilities have significantly reduced antibiotics discharge into the sea. We identified 27 antibiotics, with enrofloxacin (ERFX) and nadifloxacin (NDFX) exhibiting the highest average concentrations of 84.9 and 83.4 ng/g, respectively. Quinolones (QNs) were prominent, displaying strong co-occurrence and similar distribution patterns shaped by comparable soil-water distribution coefficient (Kd). QNs correlated positively with total antibiotic concentration, serving as indicators. We proposed a multi-dimensional risk assessment of antibiotics, encompassing ecological and antimicrobial resistance (AMR) risks, complementing each other. The assessment revealed antibiotics with distinct risks: sulfacetamide (SCM) and clindamycin (CLIN) exhibited high ecological risks, while ERFX, ciprofloxacin (CFX), norfloxacin (NFX), gatifloxacin (GTFX), moxifloxacin (MXFX), and marbofloxacin (MBFX) presented high AMR risks.
The digital economy has become a driving force for global economic development, resulting in high demand for balanced regional development. Using surname distance as a proxy variable for cultural distance, this study examined the impact of cultural differences on the development of a regional digital economy. The results of the analysis of panel data from 31 Chinese provinces from 2011 to 2019 indicated that the development of a region's digital economy positively contributes to the development of the digital economy in areas of cultural proximity. Further analysis of the mechanisms of cultural differences in the digital economy showed that cultural distance affects the development of the digital economy in a province through three mechanisms: birth rate, divorce rate, and the share of small families. Moreover, the findings suggest regional, divorce, and demographic heterogeneity in the impact of cultural distance on the digital economy.
Using the census data from 2000-2015 and a pseudo-event study design, we estimate the motherhood penalty in China and explore its association with declining fertility. We find that one-third of working women leave their jobs in the year when they give birth, and the penalty persists for over eight years. The motherhood penalty increases significantly across almost all provinces during this period, and provinces with larger increases in the penalty experience greater declines in fertility rates. Using a mover-based design, we find that the rising motherhood penalty has caused a significant decline in the total fertility rate.
WeproposeanODEapproachtosolvingmultiplechoicepolynomialprogram- ming (MCPP) after assuming that the optimum point can be approximated by the ex- pected value of so-called thermal equilibrium as usually did in simulated annealing. The explicit form of the feasible region and the affine property of the objective function are both fully exploited in transforming an MCPP problem into an ODE system. We also show theoretically that a local optimum of the former can be obtained from an equilib- rium point of the latter. Numerical experiments on two typical combinatorial problems, MAX-k-CUT and the calculation of star discrepancy, demonstrate the validity of the ODE approach, and the resulting approximate solutions are of comparable quality to those obtained by the state-of-the-art heuristic algorithms but with much less cost. When compared with the numerical results obtained by using Gurobi to solve MCPP directly, our ODE approach is able to produce approximate solutions of better quality in most instances. This paper also serves as the first attempt to use a continuous algorithm for approximating the star discrepancy.
Mineral crystallization is central to myriad natural processes from the formation of snowflakes to stalagmites, but the molecularscale mechanisms are often far more complex than models reflect. Feedbacks between the hydro-, bio-, and geo-spheres drive complex crystallization processes that challenge our ability to observe and quantify them, motivating an expansion of crystallization theories. In this article, we discuss how the driving forces and timescales of nucleation are influenced by factors ranging from simple geometric confinement to distinct interfacial solution structures involving solvent organization, electrical double layers, and surface charging effects. Taken together, these ubiquitous natural phenomena can preserve metastable intermediates, drive precipitation of undersaturated phases, and modulate crystallization in time and space.
Effective risk assessment and control of environmental antibiotic resistance depend on comprehensive information about antibiotic resistance genes (ARGs) and their microbial hosts. Advances in sequencing technologies and bioinformatics have enabled the identification of ARG hosts using metagenome-assembled contigs and genomes. However, these approaches often suffer from information loss and require extensive computational resources. Here we introduce a bioinformatic strategy that identifies ARG hosts by prescreening ARG-like reads (ALRs) directly from total metagenomic datasets. This ALR-based method offers several advantages: (1) it enables the detection of low-abundance ARG hosts with higher accuracy in complex environments; (2) it establishes a direct relationship between the abundance of ARGs and their hosts; and (3) it reduces computation time by approximately 44–96% compared to strategies relying on assembled contigs and genomes. We applied our ALR-based strategy alongside two traditional methods to investigate a typical human-impacted environment. The results were consistent across all methods, revealing that ARGs are predominantly carried by Gammaproteobacteria and Bacilli, and their distribution patterns may indicate the impact of wastewater discharge on coastal resistome. Our strategy provides rapid and accurate identification of antibiotic-resistant bacteria, offering valuable insights for the high-throughput surveillance of environmental antibiotic resistance. This study further expands our knowledge of ARG-related risk management in future.
Salt crystallization within micro-fractures poses a significant challenge in shale gas production by impeding gas diffusion. This study investigates the real-time behavior of gas flow-induced salt crystallization within a visualized micro-fracture network. Observations reveal that salt crystals initially propagate along the fracture surface before exhibiting perpendicular growth. Crystal nucleation during the saturation stage occurs within a few seconds, while subsequent growth in the supersaturated stage takes approximately 15–20 s. Gas flow drives the evaporation of immobile water, leading to salt precipitation. Furthermore, increasing gas flow rate and decreasing solution salinity are found to accelerate crystal growth. To mitigate plugging damage caused by salt crystallization, controlling pressure differences and solution salinity is crucial.
A few colonies in the Latin West (Augusta Emerita, Johnston 2017: 56-57 fn. 202-203; Abascal 2002: 284) and the Greek East (e.g. Philippi AE 1932, 21; briefly Samos IG XII,6 1:187 l. 8-11) used the annus coloniae, the year when the colony was founded, as their standard time-reckoning formula on inscriptions and perhaps other media as well. The list may include the Roman colony of Sinope, which coin issues carried legends such as C(olonia) F(elix) I(ulia) an(no) followed by (and later on simply with) Latin numerals (e.g. RPC I 2110, II 715). Curiously, since the 17th century, numismatists have observed two epochs on Sinope’s Roman period issues (e.g. Hardouin 1689: 140). There was the epoch of 45 BCE, likely the annus coloniae (e.g. RPC III 1229), as it coincided with reports of a Caesarian colony (Strab. 12.3.11). Then there was the epoch of 70 BCE (e.g. RPC VI 6501), seemingly replacing the earlier epoch, but only from the early third century onwards (Kubitschek 1908: 68-71; Magie 1950: 342 no. 42). Changing epochs was not a rare phenomenon in Anatolia, but known examples changed an earlier epoch for a later one, apparently to adapt to new circumstances, such as an imperial victory or visit (Leschhorn 1993: 439-541), and count years from a new beginning. Sinope, however, changed the epoch that was supposedly linked to the year of its colonial foundation to an earlier epoch that coincided with Lucullus’ “liberation” of Sinope from Mithridatid control. This suggests that Sinope was adapting to new circumstances that required the adaptation of an historical epoch. It is not the beginning per se, but a recaliberation of municipal history. While historical developments of Roman Sinope is not well documented in extant literary sources, and epigraphic evidence is scarce, this paper wishes to take two approaches to assess the problem of Sinope’s changing epochs. The first approach is to consider Sinope’s time-reckoning tradition. The era system that was prevalent in northern Anatolia and elsewhere during the first three centuries CE had a strong Hellenistic tradition. In this view, there may be more nuance – 45 BCE can be the annus coloniae, but it was reflecting a recent change in the city’s history, not an overhaul of the city’s established time-reckoning system, perhaps based on the Seleucid era (found on ceramic stamps, Saprykin & Fedoseev 1999: 135-143). This approach removes the Roman symbolism attached to the 45 BCE, and opens up additional possibilities for interpretation. The second approach considers the epoch of 70 BCE regionally. This epoch was primarily used at Amastris, but also attested at Abonuteichos. Both cities were described by Roman authors as prosperous in their own ways (e.g. Luc. Alex. 9, 25; Plin. Ep. 10.98). Both cities also began to issue 3 to 4 units of local bronze coinage from the reign of Trajan onwards, including the 6-assaria, associated with economic prosperity (Zajac 2023: 30-32, Tab. 1a). Epigraphic and numismatic evidence further suggest that Amastrians were mobile across the Black Sea and the Aegean, some even serving as koinon officials of Bithynian and other regional koina (Marek 2003: 63-67). There is the possibility that Sinope changed its epoch to adhere to regional time-reckoning norms set by more dominant peers. Since the 17th century, numismatists have observed two epochs on Sinope’s Roman period coin issues (e.g. Hardouin 1689: 140). There was the epoch of 45 BCE, perhaps the annus coloniae (e.g. RPC III 1229; cf. Augusta Emerita, Johnston 2017: 56-57 fn. 202-203; Abascal 2002: 284; Philippi AE 1932, 21; briefly Samos IG XII,6 1:187 l. 8-11), as it coincided with reports of a Caesarian colony (Strab. 12.3.11). Then there was the epoch of 70 BCE (e.g. RPC VI 6501), seemingly replacing the earlier epoch, but only from the early third century onwards (Kubitschek 1908: 68-71; Magie 1950: 342 no. 42). Neither changing epochs or the use of many epochs were rare phenomena. That said, known examples show cities replacing old epochs with those that commemorate new events and circumstances (Leschhorn 1993: 439-541). It is then odd for Sinope to abandon the epoch commemorating its colonial foundation in favor of an epoch 25 years earlier. Why? Leschhorn gave two potential scenarios: perhaps 70 BCE was the outcome a pro-Severan party defeating the old guard, or there was a “Gräzisierung" movement under which Sinope opted for a symbolically more acceptable epoch (Leschhorn 1993: 162), but these suggestions are limited by lack of evidence. This paper reassesses Sinope’s changing epochs with two approaches. First is a reframing of the Leschhorn’s assumed constitutional symbolism attached to the epoch of 45 BCE that leads to factionalism, and the “Roman” nature of Sinope’s so-called Kolonieära in Leschhorn’s alternative “Gräzisierung” thesis. The question asked here is whether Sinope had an established era system in place as part of its Hellenistic past. Sinope likely used the Pontic era while under Mithridatid control (Leschhorn 1993: 150). Recent discussions of stamped amphorae further indicates that the Seleucid era system was likely present if not also used at Sinope (Saprykin & Fedoseev 1999: 135-143). Further, we now have ceramic tiles time-stamped with a formula such as "s(aeculo) S(inopensis) (colonia) i(nducta) an(no) IV" (Fedoseev 2019: 16-17). If Fedoseev’s reading of the time-stamp is correct, we may consider the possibility that the saeculum Sinopensis was a system that could have accommodated multiple epochs, and the phenomenon in question was a symptom of an entrenched but adaptative time-reckoning mechanism at work. The second approach considers the epoch of 70 BCE regionally. This epoch was primarily used at Amastris, but also attested at Abonuteichos. Both cities were described by Roman authors as prosperous in their own ways (e.g. Luc. Alex. 9, 25; Plin. Ep. 10.98). Both cities also began to issue 3 to 4 units of local bronze coinage from the reign of Trajan onwards, including the 6-assaria, associated with economic prosperity (Zajac 2023: 30-32, Tab. 1a). Epigraphic and numismatic evidence further suggest that Amastrians were mobile across the Black Sea and the Aegean, some even serving as koinon officials of Bithynian and other regional koina (Marek 2003: 63-67). There is the possibility that Sinope changed its epoch to adhere to regional time-reckoning norms set by more dominant peers.
