We report a superspreading event of severe acute respiratory syndrome coronavirus 2 infection initiated at a bar in Vietnam with evidence of symptomatic and asymptomatic transmission, based on ...ministry of health reports, patient interviews, and whole-genome sequence analysis. Crowds in enclosed indoor settings with poor ventilation may be considered at high risk for transmission.
Automated teller machines (ATM) play a major role in the world economy as they enable financial transactions and hence good exchanges and consumption. ATM transaction fees are incurred to cover the ...cost of running the network and these are often settled among the members including banks and cash machine operators. In this paper, we develop a novel biform game theoretic model for members to optimally invest in the ATM network and to share the cost. This biform game includes both a cooperative game theory mechanism for interchange fee sharing and a non-cooperative counterpart to model the fact that members also wish to maximize their utilities. While the proposed coopetition framework is applicable to general ATM networks, we focus the case study on the UK ATM network thanks to the accessibility of the data in addition to the notable stability issues that the network is currently experiencing as has been widely featured by the mainstream media. On the technical side, we prove the existence of a pure Nash equilibrium, which can be computed efficiently. We also show that, under some settings, the Shapley allocation belongs to the core and hence it is not only fair to all members but also leads to a stable ATM network. In addition, we show that the Shapley value allocation dominates the current mechanism in terms of social welfare. Finally, we provide numerical analysis and managerial insights using real data on the complete UK ATM network.
•Modelling: A novel ATM biform game for profit sharing and strategic decisions.•A real-life novel application and managerial insights on the UK network of banks.•Proving the existence of the pure NE and stability of the Shapley allocation.•Proposed solution dominates the current cost sharing scheme on social welfare.•Numerical schemes for finding the Nash equilibrium and the Shapley value.
The nucleolus offers a desirable payoff-sharing solution in cooperative games, thanks to its attractive properties—it always exists and lies in the core (if the core is non-empty), and it is unique. ...The nucleolus is considered as the most ‘stable’ solution in the sense that it lexicographically minimizes the dissatisfactions among all coalitions. Although computing the nucleolus is very challenging, the Kohlberg criterion offers a powerful method for verifying whether a solution is the nucleolus in relatively small games (i.e. with the number of players
n
≤
15
). This approach, however, becomes more challenging for larger games because of the need to form and check a criterion involving possibly exponentially large collections of coalitions, with each collection potentially of an exponentially large size. The aim of this work is twofold. First, we develop an improved version of the Kohlberg criterion that involves checking the ‘balancedness’ of at most
(
n
-
1
)
sets of coalitions. Second, we exploit these results and introduce a novel descent-based constructive algorithm to find the nucleolus efficiently. We demonstrate the performance of the new algorithms by comparing them with existing methods over different types of games. Our contribution also includes the first open-source code for computing the nucleolus for games of moderately large sizes.
Tuberculous meningitis kills or disables more than half of those affected with the disease. Previous studies have been too small to determine whether adjunctive treatment with corticosteroids can ...reduce the risk of disability or death among adults with tuberculous meningitis, and the effect of coinfection with the human immunodeficiency virus (HIV) is unclear.
We performed a randomized, double-blind, placebo-controlled trial in Vietnam in patients over 14 years of age who had tuberculous meningitis, with or without HIV infection, to determine whether adjunctive treatment with dexamethasone reduced the risk of death or severe disability after nine months of follow-up. We conducted prespecified subgroup analyses and intention-to-treat analyses.
A total of 545 patients were randomly assigned to groups that received either dexamethasone (274 patients) or placebo (271 patients). Only 10 patients (1.8 percent) had been lost to follow-up at nine months of treatment. Treatment with dexamethasone was associated with a reduced risk of death (relative risk, 0.69; 95 percent confidence interval, 0.52 to 0.92; P=0.01). It was not associated with a significant reduction in the proportion of severely disabled patients (34 of 187 patients 18.2 percent among survivors in the dexamethasone group vs. 22 of 159 patients 13.8 percent in the placebo group, P=0.27) or in the proportion of patients who had either died or were severely disabled after nine months (odds ratio, 0.81; 95 percent confidence interval, 0.58 to 1.13; P=0.22). The treatment effect was consistent across subgroups that were defined by disease-severity grade (stratified relative risk of death, 0.68; 95 percent confidence interval, 0.52 to 0.91; P=0.007) and by HIV status (stratified relative risk of death, 0.78; 95 percent confidence interval, 0.59 to 1.04; P=0.08). Significantly fewer serious adverse events occurred in the dexamethasone group than in the placebo group (26 of 274 patients vs. 45 of 271 patients, P=0.02).
Adjunctive treatment with dexamethasone improves survival in patients over 14 years of age with tuberculous meningitis but probably does not prevent severe disability.
Understanding the relationship between the molecular structure and processing conditions of nanomaterials is crucial to able predict their final properties. This paper investigates the effect of some ...processing conditions dealing with heating speed; atomic numbers, atom at temperature; annealing time (t) on the phase transition and crystallization processes of an AlNi nanoparticles by using molecular dynamics (MD) method embedded with Sutton-Chen (SC) interaction potential and free boundary conditions. Quantitively structural characteristics, phase transition and crystallization process are analyzed through radial distribution function (RDF), the total energy of the system (Etot), size (D) and Common Neighborhood Analysis (CNA) methods. The different structural unit numbers of materials such as Face Centered Cubic (FCC), Hexagonal Close-Packed (HCP), Body-Centered Cubic (BCC), Amorphous (Amor) are observed with variation of inlet parameters. Besides, by using different mathematical models, various molecular parameters are determined and a relationship between size of nanoparticle (D), total energy of the system (Etot) with atomic number (N) was also established by which D ∼ N−1/3 and Etot ∼ N−1.
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•The Al atoms are found in core layers while Ni atoms are located abundantly in the shell layers of AlNi alloys.•Increase of heating rate favorited to the formation of unit numbers type BCC.•AlNi nanoparticles exhibit four elemental structures type FCC, HCP, BCC and Amor.•Relationship between molecular parameters (D, Etot and atomic number) was established.
•We develop a joint pricing and inventory model for substitutable and perishable products with stochastic demand.•We derive analytical properties of the optimal decisions such as the concavity of the ...value functions.•We develop an efficient numerical scheme for finding the optimal joint ordering and pricing policy.•We provide numerical experiments on a case study with real data as well as over 100 simulated test instances.•Numerical results show the benefits of considering substitution as well as joint pricing and inventory.
In this paper, we develop a model for dynamic pricing and inventory decisions for multiple substitutable and perishable products under a multiple-period lifetime. Retailers place orders at the beginning of the first period, and products will be sold at full price during that period. All leftover products will then be carried over to the subsequent periods and sold at discounted prices. Demands for leftover products are assumed to follow a linear stochastic model depending on the discounted prices of the substitutable products. The optimal order quantities and prices are obtained by maximizing the total expected profit over the lifetime, taking into account the revenue, the backorder cost and the holding cost. We provide analytical properties of the optimal policy such as the concavity of the value functions and then utilise these in the numerical scheme for finding the optimal prices and ordering quantities. Experimental results are reported through a case study of a high-street fashion company, demonstrating the benefits of considering pricing and inventory decisions simultaneously for substitutable products.
The linear production game is concerned with allocating the total payoff of an enterprise among the owners of the resources in a fair way. With cooperative game theory providing a mathematical ...framework for sharing the benefit of the cooperation, the Shapley value is one of the widely used solution concepts as a fair measurement in this area. Finding the exact Shapley value for linear production games is, however, challenging when the number of players exceeds 30. This paper describes the use of linear programming sensitivity analysis for a more efficient computation of the Shapley value. The paper also proposes a stratified sampling technique to estimate the Shapley value for large-scale linear production games. Computational results show the effectiveness of the proposed methods compared to others.
Environmental pollution of heavy metal(loid)s (HMs) caused adverse impacts, has become one of the emerging concerns and challenges worldwide. Metal(loid)s can pose significant threats to living ...organisms even when present in trace levels within environmental matrices. Extended exposure to these substances can lead to adverse health consequences in humans. Removing HM-contaminated water and moving toward sustainable development goals (SDGs) is critical. In this mission, biochar has recently gained attention in the environmental sector as a green and alternative material for wastewater removal. This work provides a comprehensive analysis of the remediation of typical HMs by biochars, associated with an understanding of remediation mechanisms, and gives practical solutions for ecologically sustainable. Applying engineered biochar in various fields, especially with nanoscale biochar-aided wastewater treatment approaches, can eliminate hazardous metal(loid) contaminants, highlighting an environmentally friendly and low-cost method. Surface modification of engineered biochar with nanomaterials is a potential strategy that positively influences its sorption capacity to remove contaminants. The research findings highlighted the biochars' ability to adsorb HM ions based on increased specific surface area (SSA), heightened porosity, and forming inner-sphere complexes with oxygen-rich groups. Utilizing biochar modification emerged as a viable approach for addressing lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), and chromium (Cr) pollution in aqueous environments. Most biochars investigated demonstrated a removal efficiency >90 % (Cd, As, Hg) and can reach an impressive 99 % (Pb and Cr). Furthermore, biochar and advanced engineered applications are also considered alternative solutions based on the circular economy.
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•Heavy metal(loid)s (HMs) can threaten living organisms and human health•Biochar nano-adsorbents with promoted surface functionalities for better adsorption•Biochar-based HM treatment can reach SDG 6 on ensuring sanitation and safe water•Biochar has gained attention as a green material for wastewater removal•Develop and optimize biochar-based WWTPs to mitigate current challenges
Background.Tuberculous meningitis occurs more commonly in human immunodeficiency virus (HIV)–infected individuals than in HIV-uninfected individuals, but whether HIV infection alters the presentation ...and outcome of tuberculous meningitis is unknown MethodsWe performed a prospective comparison of the presenting clinical features and response to treatment in 528 adults treated consecutively for tuberculous meningitis (96 were infected with HIV and 432 were uninfected with HIV) in 2 tertiary-care referral hospitals in Ho Chi Minh City, Vietnam. Logistic regression was used to model variables associated independently with HIV infection, 9-month survival, and the likelihood of having a relapse or an adverse drug event. Kaplan-Meier estimates were used to compare survival rates and times to fever clearance, coma clearance, relapse, and adverse events ResultsHIV infection did not alter the neurological presentation of tuberculous meningitis, although additional extrapulmonary tuberculosis was more likely to occur in HIV-infected patients. The 9-month survival rate was significantly decreased in HIV-infected patients (relative risk of death from any cause, 2.91 95% confidence interval, 2.14–3.96; P<.001), although the times to fever clearance and coma clearance and the number or timing of relapses or adverse drug events were not significantly different between the groups ConclusionsHIV infection does not alter the neurological features of tuberculous meningitis but significantly reduces the survival rate
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