Diffusion and localization of relative strategy scores in the Minority Game

We study the equilibrium distribution of relative strategy scores of agents in the asymmetric phase ($\alpha\equiv P/N\gtrsim 1$) of the basic Minority Game using sign-payoff, with $N$ agents holding two strategies over $P$ histories. We formulate a statistical model that makes use of the gauge freedom with respect to the ordering of an agent's strategies to quantify the correlation between the attendance and the distribution of strategies. The relative score $x\in\mathbb{Z}$ of the two strategies of an agent is described in terms of a one dimensional random walk with asymmetric jump probabilities, leading either to a static and asymmetric exponential distribution centered at $x=0$ for fickle agents or to diffusion with a positive or negative drift for frozen agents. In terms of scaled coordinates $x/\sqrt{N}$ and $t/N$ the distributions are uniquely given by $\alpha$ and in quantitative agreement with direct simulations of the game. As the model avoids the reformulation in terms of a constrained minimization problem it can be used for arbitrary payoff functions with little calculational effort and provides a transparent and simple formulation of the dynamics of the basic Minority Game in the asymmetric phase

Catching Cheats: Detecting Strategic Manipulation in Distributed Optimisation of Electric Vehicle Aggregators

Given the rapid rise of electric vehicles (EVs) worldwide, and the ambitious targets set for the near future, the management of large EV fleets must be seen as a priority. Specifically, we study a scenario where EV charging is managed through self-interested EV aggregators who compete in the day-ahead market in order to purchase the electricity needed to meet their clients' requirements. With the aim of reducing electricity costs and lowering the impact on electricity markets, a centralised bidding coordination framework has been proposed in the literature employing a coordinator. In order to improve privacy and limit the need for the coordinator, we propose a reformulation of the coordination framework as a decentralised algorithm, employing the Alternating Direction Method of Multipliers (ADMM). However, given the self-interested nature of the aggregators, they can deviate from the algorithm in order to reduce their energy costs. Hence, we study the strategic manipulation of the ADMM algorithm and, in doing so, describe and analyse different possible attack vectors and propose a mathematical framework to quantify and detect manipulation. Importantly, this detection framework is not limited the considered EV scenario and can be applied to general ADMM algorithms. Finally, we test the proposed decentralised coordination and manipulation detection algorithms in realistic scenarios using real market and driver data from Spain. Our empirical results show that the decentralised algorithm's convergence to the optimal solution can be effectively disrupted by manipulative attacks achieving convergence to a different non-optimal solution which benefits the attacker. With respect to the detection algorithm, results indicate that it achieves very high accuracies and significantly outperforms a naive benchmark

The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae), in Mexico City

<p>Abstract</p> <p>Background</p> <p><it>Culex </it>spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, <it>Culex pipiens pipiens, Culex pipiens quinquefasciatus</it>, and <it>Culex tarsalis </it>are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of <it>Culex pipiens </it>complex mosquitoes and hybrids in Mexico City. <it>Culex pipiens pipiens </it>preferentially feed on avian hosts; <it>Culex pipiens quinquefasciatus </it>have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of <it>Culex pipiens </it>complex mosquitoes and their hybrids.</p> <p>Results</p> <p>Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as <it>Culex, Culiseta </it>or <it>Ochlerotatus </it>by morphological analysis. Within the genus <it>Culex</it>, specimens were further identified as <it>Culex tarsalis </it>or as belonging to the <it>Culex pipiens </it>complex. Members of the <it>Culex pipiens </it>complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio) of the male genitalia and also by using diagnostic primers designed for the <it>Ace.2 </it>gene. <it>Culex pipiens quinquefasciatus </it>was the most abundant form collected.</p> <p>Conclusions</p> <p>Important WNV vectors species, <it>Cx. p. pipiens</it>, <it>Cx. p. quinquefasciatus </it>and <it>Cx. tarsalis</it>, are all present in Mexico City. Hybrids of <it>Cx. p. pipiens </it>and <it>Cx. p. quinquefasciatus </it>were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.</p

Epidemiological implications of the genetic diversification of dengue virus (DENV) serotypes and genotypes in Mexico

Variation and clade shifts in dengue virus (DENV) genotypes are responsible for numerous dengue fever outbreaks throughout Latin America in the past decade. Molecular analyses of dengue serotypes have revealed extensive genetic diversification and the emergence of new genotypes in Brazil (DENV-4 genotype I) and elsewhere in tropical and subtropical America. The goal of the present study is to assess the extent to which the adventitious introduction of DENV genotypes and their increasing genetic diversity affects dengue epidemiology in Mexico. A nuanced sequence inspection and phylogenetic analysis of the C-prM nucleotide region of DENV was performed for specimens collecting in 2009 from the Veracruz State, Mexico. Findings were contrasted with specimens collected in adjacent years and analysed based on the epidemiological patterns reported between 1990 and 2019. Additionally, the identification process of various DENV genotypes was assessed, including: (1) DENV-1, genotype V, (2) the DENV-2 Asian/American and Asian II genotypes (3) DENV-3, genotype III, and (4) DENV-4, genotype I. This resulted in the discovery of a distinct genetic cladistic pattern for serotype DENV-2. Lastly, study findings suggest that a correlation exists between the emergence of novel genotypes and genetic diversification, with the increasing incidence of DENV infections in Mexico in 2009

Looking for Crumbs in the Obesity Forest: Anti-obesity Interventions and Obesity-Associated Cardiometabolic Traits in the Mexican Population. History and Systematic Review With Meta-Analyses

Mexicans and Mexican Americans share culture, genetic background, and predisposition for chronic complications associated with obesity and diabetes making imperative efficacious treatments and prevention. Obesity has been treated for centuries focused-on weight loss while other treatments on associated conditions like gout, diabetes (T2D), and hypertriglyceridemia. To date, there is no systematic review that synthesizes the origin of obesity clinics in Mexico and the efforts to investigate treatments for obesity tested by randomized clinical trials (RCT). We conducted systematic searches in Pubmed, Scopus, and Web of Science to retrieve anti-obesity RCT through 2019 and without an inferior temporal limit. The systematic review included RCT of anti-obesity treatments in the Mexican adult population, covering alternative medicine, pharmacological, nutritional, behavioral, and surgical interventions reporting metabolism-associated traits such as BMI, weight, waist circumference, triglycerides, glucose, among others. Only the studies with at least 3 months of treatment were included in the meta-analyses in order to reduce placebo effects. We found 634 entries, after removal of duplicates and screening the studies based on eligibility criteria, we analyzed 43 national, and 2 multinational-collaborative studies. Most of the national studies had small sample sizes, and the implemented strategies do not have replications in the population. The nutrition/behavioral interventions were difficult to blind, and most studies have medium-to-high risk of bias. Nutritional/behavioral interventions and medications showed effects on BMI, waist circumference, and blood pressure. Simple measures like pure water instead of sweet beverages decrease triglycerides and systolic blood pressure. Dark chocolate showed the highest effect for BMI and high blood pressure, and treatment with insulin increased weight in those with T2D. The study of obesity in Mexico has been on-going for more than four decades, the interest on RCT just increased until this millennium, but with small sample sizes and lack of replication. The interventions affect different cardiometabolic associated traits, which should be analyzed in detail in the population living near the Mexico-U.S. border; therefore, bi-national collaboration is desirable to disentangle the cultural effects on this population\u27s treatment response

Fat Distribution and Differential Effects on Metabolic Liver Fat Infiltration in Young Mexicans in Reynosa, Mexico: A Collaborative Study across the U.S.-Mexico Border

Introduction: Metabolic-associated fatty liver disease (MAFLD) is a descriptive term for NAFLD (Non-alcoholic) physiopathology associated with obesity. The age of onset linked to body fat distribution is poorly studied. Therefore, we aimed to assess the body fat effect on liver fat infiltration and stiffness (LSt) mediated by insulin resistance (IR). Methods: After obtaining informed consent, five hundred freshmen from two universities in Reynosa, Mexico (UMAN & UAT) were enrolled in the study. They completed a questionnaire focused on familial cardiometabolic risk and provided anthropometric measurements. In a subset of N=200, we obtained blood samples for biochemical measurements, body fat percentage (BF%) by bioimpedance, LSt (kPa), and fat infiltration (Continued Attenuation Parameter, CAP) by elastography. We used mediation analysis with structural equation models (Stata v16.1) to determine the relationship between BMI, BF%, and abdominal obesity with IR and liver stiffness and fat infiltration. The term “-\u3e” means ‘explain’ or ‘cause’. Results: We found that AO-\u3eIR (standardized values b=0.53, p=0.005), AO-\u3eCAP (b=0.69, pIR (b=0.23, p=0.007). BMI did not have an effect on CAP or IR. Also, BMI-\u3eLS (b=0.47, p=0.05) but AO-\u3eLS was absent. Finally, there was a bidirectional relationship between LS and IR [LS-\u3eIR (b=0.18, p=0.001), and IR-\u3eLS (b=0.27, p=0.001)]. Conclusion: Our findings suggest the adipose tissue measured as AO or BMI showed different phenotypic effects on liver fat infiltration or stiffness. Visceral fat had a direct effect on IR, meanwhile, subcutaneous adipose tissue was associated with liver stiffness. Our findings suggest that early age interventions should be focused on reducing visceral fat deposition

Neutralizing anti-RBD fraction for SARS-CoV-2 is associated with the interaction waist circumference and sex. An ESFUERSO preliminary report on university students

In a previous study we reported that 25% of college students had a family history of type 2 diabetes (T2D), and 39% of hypertension. Interestingly, between 17 to 47% reported not knowing about T2D or hypertension, neither the existing obesity-metabolic problems (ESFUERSO study). The COVID-19 pandemic forced confinement and modifications in food intake, physical activity, and psychological stress. This study aimed to analyze if the immune Ig-G anti-RBD (protective epitope in S protein) response associated with type of vaccination, metabolic risk, perceived stress, and history of COVID-19 contacts. We included 116 students at the 3th year of follow up in the ESFUERSO cohort at Reynosa. Mean age 21.4 (SD 1.04) years old, BMI 28 (6.6), females 70% (81/116). The serum concentration of Ig-G anti-RGB measured by ELISA adjusted by sex, age, body fat percentage, and BMI was analyzed. Researchers performed a multiple regression analysis with Stata V17.0. We found that 70% of the students had a family history of diabetes, hypertension, and/or obesity at baseline. Only 5 (4%) students did not have any vaccine at the time of the study, 102 (88%) were vaccinated with Moderna or Pfizer and 9 (8%) with other vaccines (Cansino, Sinovac). The prevalence of positive anti-RBD was 91%. The body fat percentage interacted with sex (p=0.034) explaining the serum concentration of anti-RBD decreased as adiposity increases in men, but increased in women. The interaction remained is spite of type of vaccination. We found no differences among metabolic risks for food consumption, distress, uncertainty, lack of sleep, sadness, and anxiety were associated with metabolic problems. Our model predicts neutralizing anti-RBD had multiplicative interaction by sex and body fat percentage (increases in females and decreases in males), with no effects on stress score or food consumption