Thermodynamic selection: mechanisms and scenarios.

Thermodynamic selection is an indirect competition between agents feeding on the same energy resource and obeying the laws of thermodynamics. We examine scenarios of this selection, where the agent is modeled as a heat-engine coupled to two thermal baths and extracting work from the high-temperature bath. The agents can apply different work-extracting, game-theoretical strategies, e.g. the maximum power or the maximum efficiency. They can also have a fixed structure or be adaptive. Depending on whether the resource (i.e. the high-temperature bath) is infinite or finite, the fitness of the agent relates to the work-power or the total extracted work. These two selection scenarios lead to increasing or decreasing efficiencies of the work-extraction, respectively. The scenarios are illustrated via plant competition for sunlight, and the competition between different ATP production pathways. We also show that certain general concepts of game-theory and ecology-the prisoner's dilemma and the maximal power principle-emerge from the thermodynamics of competing agents. We emphasize the role of adaptation in developing efficient work-extraction mechanisms.

Age-structured SIR model and resource growth dynamics: a COVID-19 study.

In this paper, we discuss three different response strategies to a disease outbreak and their economic implications in an age-structured population. We have utilized the classical age structured SIR-model, thus assuming that recovered people will not be infected again. Available resource dynamics is governed by the well-known logistic growth model, in which the reproduction coefficient depends on the disease outbreak spreading dynamics. We further investigate the feedback interaction of the disease spread dynamics and resource growth dynamics with the premise that the quality of treatment depends on the current economic situation. The very inclusion of mortality rates and economic considerations in the same model may be incongruous under certain positions, but in this model, we take a "realpolitik" approach by exploring all of these factors together as it is done in reality.

Cooperate or Not Cooperate in Predictable but Periodically Varying Situations? Cooperation in Fast Oscillating Environment.

In this work, the cooperation problem between two populations in a periodically varying environment is discussed. In particular, the two-population prisoner's dilemma game with periodically oscillating payoffs is discussed, such that the time-average of these oscillations over the period of environmental variations vanishes. The possible overlaps of these oscillations generate completely new dynamical effects that drastically change the phase space structure of the two-population evolutionary dynamics. Due to these effects, the emergence of some level of cooperators in both populations is possible under certain conditions on the environmental variations. In the domain of stable coexistence the dynamics of cooperators in each population form stable cycles. Thus, the cooperators in each population promote the existence of cooperators in the other population. However, the survival of cooperators in both populations is not guaranteed by a large initial fraction of them.

Can Environmental Manipulation Help Suppress Cancer? Non-Linear Competition Among Tumor Cells in Periodically Changing Conditions.

It has been shown that the tumor population growth dynamics in a periodically varying environment can drastically differ from the one in a fixed environment. Thus, the environment of a tumor can potentially be manipulated to suppress cancer progression. Diverse evolutionary processes play vital roles in cancer progression and accordingly, understanding the interplay between these processes is essential in optimizing the treatment strategy. Somatic evolution and genetic instability result in intra-tumor cell heterogeneity. Various models have been developed to analyze the interactions between different types of tumor cells. Here, models of density-dependent interaction between different types of tumor cells under fast periodical environmental changes are examined. It is illustrated that tumor population densities, which vary on a slow time scale, are affected by fast environmental variations. Finally, the intriguing density-dependent interactions in metastatic castration-resistant prostate cancer (mCRPC) in which the different types of tumor cells are defined with respect to the production of and dependence on testosterone are discussed.

Adaptive Heat Engine.

A major limitation of many heat engines is that their functioning demands on-line control and/or an external fitting between the environmental parameters (e.g., temperatures of thermal baths) and internal parameters of the engine. We study a model for an adaptive heat engine, where-due to feedback from the functional part-the engine's structure adapts to given thermal baths. Hence, no on-line control and no external fitting are needed. The engine can employ unknown resources; it can also adapt to results of its own functioning that make the bath temperatures closer. We determine resources of adaptation and relate them to the prior information available about the environment.

Hepatocellular carcinoma surveillance rates in commercially insured patients with noncirrhotic chronic hepatitis B.

American association for the study of liver diseases (AASLD) and European Association for the Study of the Liver (EASL) guidelines recommend biannual hepatocellular carcinoma (HCC) screening for noncirrhotic patients with chronic hepatitis B infection (HBV), yet there are no data estimating surveillance rates or factors associated with surveillance. We performed a retrospective cohort study of US patients using the Truven Health Analytics databases from 2006 to 2010 and identified patients with noncirrhotic chronic HBV. Surveillance patterns were characterized using categorical and continuous outcomes, with the continuous measure of the proportion of time 'up to date' with surveillance (PUTDS), with the 6-month interval following each ultrasound categorized as 'up to date'. During a median follow-up of 26.0 (IQR: 16.2-40.0) months among 4576 noncirrhotic patients with chronic HBV (median age: 44 years, IQR: 36-52), only 306 (6.7%) had complete surveillance (one ultrasound every 6-month interval), 2727 (59.6%) incomplete (≥1 ultrasound) and 1543 (33.7%) none. The mean PUTDS was 0.34 ± 0.29, and the median was 0.32 (IQR: 0.03-0.52). In multinomial logistic regression models, patients diagnosed by a nongastroenterologist were significantly less likely to have complete surveillance (P < 0.001), as were those coinfected with HBV/HIV (P < 0.001). In linear regression models, nongastroenterologist provider, health insurance subtype, HBV/HIV coinfection, rural status and metabolic syndrome were independently associated with decreased surveillance. Patients with HIV had an absolute decrease in the PUTDS of 0.24, while patients in less populated rural areas had an absolute decrease of 0.10. HCC surveillance rates in noncirrhotic patients with chronic HBV in the United States are poor and lower than reported rates of HCC surveillance in cirrhotic patients.