Stability and bifurcations in transportation networks with heterogeneous users

A critical aspect in strategic modeling of transportation systems is user heterogeneity. In many real-world scenarios, e.g., when tolls are charged and drivers have different trade-offs between time and money, or when they get informed about current congestion by different routing apps, modeling users as rational decision makers with homogeneous utility functions becomes too restrictive. While global asymptotic stability of user equilibria in homogeneous routing games is known to hold for a broad class of evolutionary dynamics, the stability analysis of user equilibria in heterogeneous routing games is a largely open problem. In this work we study the logit dynamics in heterogeneous routing games on arbitrary network topologies. We show that the dynamics may exhibit bifurcations as the noise level of the dynamics varies, and provide sufficient conditions for asymptotic stability of user equilibria.Comment: 8 pages, 5 figures. Full version of accepted paper for the 2022 61th IEEE Conference on Decision and Control (CDC

Oracle Complexity Reduction for Model-free LQR: A Stochastic Variance-Reduced Policy Gradient Approach

We investigate the problem of learning an $\epsilon$-approximate solution for the discrete-time Linear Quadratic Regulator (LQR) problem via a Stochastic Variance-Reduced Policy Gradient (SVRPG) approach. Whilst policy gradient methods have proven to converge linearly to the optimal solution of the model-free LQR problem, the substantial requirement for two-point cost queries in gradient estimations may be intractable, particularly in applications where obtaining cost function evaluations at two distinct control input configurations is exceptionally costly. To this end, we propose an oracle-efficient approach. Our method combines both one-point and two-point estimations in a dual-loop variance-reduced algorithm. It achieves an approximate optimal solution with only $O\left(\log\left(1/\epsilon\right)^{\beta}\right)$ two-point cost information for $\beta \in (0,1)$

Learning Personalized Models with Clustered System Identification

We address the problem of learning linear system models from observing multiple trajectories from different system dynamics. This framework encompasses a collaborative scenario where several systems seeking to estimate their dynamics are partitioned into clusters according to their system similarity. Thus, the systems within the same cluster can benefit from the observations made by the others. Considering this framework, we present an algorithm where each system alternately estimates its cluster identity and performs an estimation of its dynamics. This is then aggregated to update the model of each cluster. We show that under mild assumptions, our algorithm correctly estimates the cluster identities and achieves an approximate sample complexity that scales inversely with the number of systems in the cluster, thus facilitating a more efficient and personalized system identification process

Efectos de la administración neonatal de zeranol sobre testículos de terneros y peso corporal

To determine if zeranol neonatal implants (NI) produce testes alterations the same way as the estrogenic hormones,20 male Abeerden Angus calves were used divided in two gruops of equal number. The implanted group (IG) received a 24 mg zeranol NI while the control group (CG) did not get any treatment. The animals were weighed at birth and at 8 months of age, when they were castrated. The body weight gain between the IG was compared and testicular development difference between both groups was estimated through testes weight. A decrease of testes development (p0.001) and an increase in body weight gain (p0.10) were found in the IG regarding the CG. It is concluded that zeranol NI upon the testes and body gain, produces a similar effect to that of the estrogenic gonad hormonesPara determinar si los implantes neonatales (IN) de zeranol producen alteracioneste sticulares al igual que las hormonas estrogénicas se utilizaron 20 terneros machos Aberdeen Angus divididos en dos grupos de igual número. El Grupo Implantado (GI) recibió un IN de 24 mg de zeranol mientras que el Grupo Testigo (GT) no recibió ningún tratamiento. Los animales fueron pesados al nacimiento y a los 8 meses de edad, momento en que fueron castrados. Se comparó la ganancia de peso corporal entre el GI y el GT y se estimó la diferencia del desarrollo testicular entre ambos grupos a través del peso de los testículos. Se encontró una disminución del desarrollo testicular (p<0,001) y un aumento de la ganancia de peso corporal (p<0,10) en el GI respecto al GT. Se concluye que el IN de zeranol produce sobre los testículos y la ganancia de peso corporal un efecto similar a la aplicaciónn eonatald e las hormonal gonadalese strogénica

Comparison of selectivity of a family of chelating agents for trivalent (Al³⁺, Fe³⁺) and bivalent (Cu²⁺, Zn²⁺) metal ions

Chelation therapy is used for the treatment of metal intoxication in humans. Selectivity towards the target metal ion is one important characteristic of the chelating agent. In the frame of our research of chelating agents for iron and aluminium, we synthesized five new ligands (Figure 1), and studied their behavior toward the trivalent metal ions. L4, L5, L6 and L8 were found to be excellent ligands for the coordination of Fe3+ and Al3+. We are presenting here a study on the same ligands with the two essential bivalent metal ions, Zn2+ and Cu2+. The results of spectrophotometric, potentiometric, and NMR measurements performed to determine the equilibrium formation constants will be presented. The speciation of the complexes with the trivalent metal ions in presence of endogenous zinc and copper will be discussed

Clinical discussions in antithrombotic therapy management in patients with atrial fibrillation: a delphi consensus panel

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OUTCOMES OF ELDERLY PATIENTS WITH ST-ELEVATION OR NON-ST-ELEVATION ACUTE CORONARY SYNDROME UNDERGOING PERCUTANEOUS CORONARY INTERVENTION

Acute coronary syndromes have been classified according to the finding of ST-segment elevation on the presenting ECG, with different treatment strategies and practice guidelines. However, a comparative description of the clinical characteristics and outcomes of acute coronary syndrome elderly patients undergoing percutaneous coronary intervention during index admission has not been published so far

A New hydroxypyrone powerful chelator: from synthesis to Al^III, Fe^III, Cu^II and Zn^II complex formation equilibria, and structural characterization

In the frame of our research interest on kojic acid derivatives as powerful chelators for the trivalent iron and aluminium cations [1-4], we have designed, synthesized, and characterized the new ligand 6,6'-(((2-(diethylamino)ethyl)azanediyl)bis(methylene))bis(5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one), L9. In this communication will be present the study on protonation constants and on the complex formation equilibria with iron and aluminium and with the bivalent essential metal ions, zinc and copper. X-ray structures of the ligand and of some of its metal complexes will be also presented

One-Year Mortality in Elderly Adults with Non-ST-Elevation Acute Coronary Syndrome: Effect of Diabetic Status and Admission Hyperglycemia

OBJECTIVES: To determine whether type 2 diabetes mellitus and hyperglycemia on admission should be considered independent predictors of mortality in elderly adults with acute coronary syndrome (ACS). DESIGN: Prospective cohort study. SETTING: Twenty-three hospitals in Italy. PARTICIPANTS: Individuals aged 75 and older with non-ST-elevation ACS (NSTEACS) (mean age 82, 47% female) (N = 645). MEASUREMENTS: Diabetic status and blood glucose levels were assessed on admission. Hyperglycemia was defined as glucose greater than 140 mg/dL. Multivariable Cox proportional hazard regression was used to assess the potential confounding effect of major covariates on the association between diabetic status, admission glucose, and 1-year mortality. RESULTS: A history of diabetes mellitus was found in 231 participants (35.8%), whereas 257 (39.8%) had hyperglycemia. Hyperglycemia was found in 171 participants with diabetes mellitus (70%) and 86 (21%) without diabetes mellitus. Participants with diabetes mellitus were significantly (P < .05) more likely to have had prior myocardial infarction and stroke and had lower ejection fraction and blood hemoglobin. Hyperglycemia was associated with lower (P < .05) ejection fraction and estimated glomerular filtration rate (eGFR). Diabetic status and hyperglycemia were associated with greater 1-year mortality according to univariate analysis (54 participants with diabetes mellitus died (23.4%), versus 66 (15.9%) without diabetes mellitus (hazard ratio (HR) = 1.5 95% confidence interval (CI) = 1.0-2.1), and 60 participants with hyperglycemia died (23.3%), versus 60 (15.5%) without hyperglycemia (HR=1.6; 95% CI = 1.1-2.2), but this association was not statistically significant after adjustment for ejection fraction, age, blood hemoglobin, and eGFR. CONCLUSION: In elderly adults with NSTEACS, diabetes mellitus and hyperglycemia on admission are associated with higher mortality, mostly because of preexisting cardiovascular and renal damage. J Am Geriatr Soc 2014

Assessing the impact of COVID-19 on liver cancer management (CERO-19)

Background & Aims: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems and it may have heavily impacted patients with liver cancer (LC). Herein, we evaluated whether the schedule of LC screening or procedures has been interrupted or delayed because of the COVID-19 pandemic. Methods: An international survey evaluated the impact of the COVID-19 pandemic on clinical practice and clinical trials from March 2020 to June 2020, as the first phase of a multicentre, international, and observational project. The focus was on patients with hepatocellular carcinoma or intrahepatic cholangiocarcinoma, cared for around the world during the first COVID-19 pandemic wave. Results: Ninety-one centres expressed interest to participate and 76 were included in the analysis, from Europe, South America, North America, Asia, and Africa (73.7%,17.1%, 5.3%, 2.6%, and 1.3% per continent, respectively). Eighty-seven percent of the centres modified their clinical practice: 40.8% the diagnostic procedures, 80.9% the screening programme, 50% cancelled curative and/or palliative treatments for LC, and 41.7% modified the liver transplantation programme. Forty-five out of 69 (65.2%) centres in which clinical trials were running modified their treatments in that setting, but 58.1% were able to recruit new patients. The phone call service was modified in 51.4% of centres which had this service before the COVID-19 pandemic (n = 19/37). Conclusions: The first wave of the COVID-19 pandemic had a tremendous impact on the routine care of patients with liver cancer. Modifications in screening, diagnostic, and treatment algorithms may have significantly impaired the outcome of patients. Ongoing data collection and future analyses will report the benefits and disadvantages of the strategies implemented, aiding future decision-making. Lay summary: The coronavirus disease 2019 (COVID-19) pandemic has posed unprecedented challenges to healthcare systems globally. Herein, we assessed the impact of the first wave pandemic on patients with liver cancer and found that routine care for these patients has been majorly disrupted, which could have a significant impact on outcomes. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL)