teoria evolutiva dei giochi

Nella sua tesi di dottorato, mai pubblicata, il popolare matematico John Nash suggeriva un'interpretazione del suo concetto di equilibrio nell'ambito di giochi tra individui scelti a caso da vaste popolazioni, individui che non devono necessariamente avere una conoscenza dell'intera struttura del gioco, o l'abilita' di effettuare complicati processi razionali. E' di questo tipo di giochi che si occupa la teoria evolutiva dei giochi, che puo' essere considerata come un'estensione della teoria dei giochi classica. L'interesse per questo argomento nacque nel 1973, quando John Maynard Smith e George R.Price formalizzarono alcune problematiche che sorgono nel contesto della biologia. Sono proprio le scienze biologiche, insieme a quelle economiche e sociali, le discipline in cui la teoria evolutiva dei giochi trova un numero sempre maggiore di applicazioni. Le principali differenze rispetto alla teoria dei giochi classica risiedono nel fatto che in un gioco evolutivo i giocatori, ovvero individui scelti a caso da una vasta popolazione, non hanno la capacita' di analizzare razionalmente il gioco; e' l'interazione tra i vari giocatori a determinare la scelta delle strategie, e quelle che producono un maggiore guadagno risulteranno essere usate piu' di frequente. I giocatori potrebbero addirittura non avere consapevolezza del guadagno che una determinata strategia produce; esiste tuttavia una 'legge' che li indirizza verso strategie sempre piu' proficue: questo avviene, per esempio, nella modifica della frequenza delle caratteristiche genetiche delle specie viventi operata dalla selezione naturale, descrivibile attraverso un modello semplificato di cui ci occuperemo nell'ultimo capitolo. Nel primo capitolo vengono presentati sia i concetti basilari della teoria dei giochi classica, sia gli strumenti necessari per la trattazione successiva: le definizioni di gioco, payoff, strategie miste, equilibri di Nash, insieme a qualche esempio di gioco e ai fatti fondamentali, come il teorema di esistenza di un equilibrio misto di Nash per un gioco discreto a due giocatori. Il secondo capitolo introduce la teoria evolutiva, nella quale si ha una popolazione di giocatori sottoposti, in maniera casuale, a un gioco a due giocatori discreto e simmetrico: tra le possibili strategie alcune possono rivelarsi evolutivamente stabili, vale a dire che quando vengono adottate dall'intera popolazione resistono, in un ben precisato senso, a mutazioni (di strategie) di una piccola percentuale dei giocatori. Per questo tipo di giochi e' stata ipotizzata una dinamica, detta della replicazione, secondo cui il tasso di incremento, al variare del tempo, della frequenza della strategia i-esima tra la popolazione e' dato dalla differenza tra il payoff, che tale strategia ottiene contro un giocatore a caso, e il payoff medio. Nel corso del capitolo vengono analizzati alcuni teoremi che legano stabilita' statica, evolutiva e dinamica: per esempio, usando gli strumenti classici dei sistemi dinamici, si dimostra che una strategia evolutivamente stabile si rivela un punto di equilibrio asintoticamente stabile nella dinamica associata al gioco. La trattazione e' corredata da numerosi esempi, alcuni dei quali comprendono casi patologici. E' possibile riformulare alcuni dei concetti descritti per applicarli a giochi lievemente diversi, come quelli in cui i guadagni non sono necessariamente lineari, o nei quali si scontrano due popolazioni distinte, con distinte matrici dei payoff. Proprio a questo tipo particolare di giochi ci si puo' riferire per affrontare una questione di attualita' negli studi sociali: il problema delle pubblicazioni scientifiche open access. Nel terzo capitolo mostriamo che la situazione puo' essere modellata come un gioco tra una popolazione di scienziati e una di editori che hanno a disposizione la scelta tra open access e non open access; le caratteristiche dei payoff spingono a studiare il gioco da un punto di vista dinamico. Ne risulta una periodica redistribuzione delle frequenze delle strategie tra le due popolazioni. Questo modello, recentemente proposto da Katharina e Lutx Habermann, presenta alcuni aspetti che possono essere resi piu' realistici: si e' scelto di migliorarlo, prima modificando alcune ipotesi e poi introducendo dei payoff non lineari; l'evoluzione nei due casi presenta alcune differenze. Come gia' anticipato, viene studiata infine un'altra possibile applicazione della teoria evolutiva dei giochi: la formalizzazione del processo di selezione naturale, nel quale si riduce la frequenza delle caratteristiche genetiche che peggio si adattano all'ambiente in cui sono inserite. In alcuni casi, conoscendo tutte le combinazioni di geni possibili in una popolazione, e il relativo tasso di sopravvivenza, si puo' calcolare come varia la frequenza dei cosiddetti genotipi all'interno della popolazione, al continuo susseguirsi delle generazioni. Ne viene fuori un'equazione della replicazione, associata a un curioso gioco in cui i giocatori risultano essere i geni, mentre gli esseri viventi costituiscono solo il tavolo da gioco. Per questo gioco vengono ricavati alcuni risultati particolari, che si aggiungono a quelli esaminati nel secondo capitolo: per esempio una caratteristica dell'equazione della selezione naturale e' la corrispondenza biunivoca tra punti di equilibrio asintoticamente stabili e strategie evolutivamente stabili

Exploring the Viability of Utilizing TreatedWastewater as a Sustainable Water Resource for Green Hydrogen Generation Using Solid Oxide Electrolysis Cells (SOECs)

The European Union aims to achieve carbon neutrality by 2050, prompting substantial investments in sustainable energy research, particularly in the realm of renewable sources (RESs). Italy, anticipating an energy demand of 366 TWh by 2030, is obligated by the EU to fulfill 75% to 84% of this demand through RESs1. A promising solution to meet this requirement is the production of green hydrogen through water electrolysis, specifically employing Solid Oxide Electrolysis Cells (SOECs). SOECs offer advantages over Alkaline Electrolyzers (AEs) and Proton Exchange Membranes (PEMs) since they can utilize treated wastewaters, eliminating the necessity for pure water, which is already scarce. This study centers on exploring the potential of SOECs to operate effectively in high-temperature conditions and utilize water in its gaseous form as the inlet source, commencing with treated wastewaters derived from municipal wastewater treatment plants

Assessing the use of Treated Wastewater for Green Hydrogen via SOEC

The European Union's goal of achieving carbon neutrality by 2050 has led to significant investments in sustainable energy research, particularly from renewable sources (RESs). Italy, with a projected energy demand of 366 TWh by 2030, is mandated by the EU to satisfy 75% to 84% of this demand using RESs1. Green hydrogen production through water electrolysis, particularly using Solid Oxide Electrolysis Cells (SOECs), is seen as a promising solution. SOECs have an advantage over Alkaline Electrolyzers (AEs) and Proton Exchange Membranes (PEMs) as they can use treated wastewaters, eliminating the need for pure water, which is already in short supply. This study focuses on the potential of SOECs to operate effectively in high temperature conditions and use water in its gas form as the inlet source, starting with treated wastewaters from municipal wastewater treatment plants

Serotonin drives striatal synaptic plasticity in a sex-related manner.

Abstract Introduction Plasticity at corticostriatal synapses is a key substrate for a variety of brain functions – including motor control, learning and reward processing – and is often disrupted in disease conditions. Despite intense research pointing toward a dynamic interplay between glutamate, dopamine (DA), and serotonin (5-HT) neurotransmission, their precise circuit and synaptic mechanisms regulating their role in striatal plasticity are still unclear. Here, we analyze the role of serotonergic raphe-striatal innervation in the regulation of DA-dependent corticostriatal plasticity. Methods Mice (males and females, 2–6 months of age) were housed in standard plexiglass cages at constant temperature (22 ± 1 °C) and maintained on a 12/12 h light/dark cycle with food and demineralized water ad libitum. In the present study, we used a knock-in mouse line in which the green fluorescent protein reporter gene (GFP) replaced the I Tph2 exon (Tph2GFP mice), allowing selective expression of GFP in the whole 5-HT system, highlighting both somata and neuritis of serotonergic neurons. Heterozygous, Tph2+/GFP, mice were intercrossed to obtain experimental cohorts, which included Wild-type (Tph2+/+), Heterozygous (Tph2+/GFP), and Mutant serotonin-depleted (Tph2GFP/GFP) animals. Results Using male and female mice, carrying on different Tph2 gene dosages, we show that Tph2 gene modulation results in sex-specific corticostriatal abnormalities, encompassing the abnormal amplitude of spontaneous glutamatergic transmission and the loss of Long Term Potentiation (LTP) in Tph2GFP/GFP mice of both sexes, while this form of plasticity is normally expressed in control mice (Tph2+/+). Once LTP is induced, only the Tph2+/GFP female mice present a loss of synaptic depotentiation. Conclusion We showed a relevant role of the interaction between dopaminergic and serotonergic systems in controlling striatal synaptic plasticity. Overall, our data unveil that 5-HT plays a primary role in regulating DA-dependent corticostriatal plasticity in a sex-related manner and propose altered 5-HT levels as a critical determinant of disease-associated plasticity defects

Cellular immune profiling of lung and blood compartments in patients with SARS-CoV-2 infection

Background: SARS-CoV-2 related immunopathology may be the driving cause underlying severe COVID-19. Through an immunophenotyping analysis on paired bronchoalveolar lavage fluid (BALF) and blood samples collected from mechanically ventilated patients with COVID-19-associated Acute Respiratory Distress Syndrome (CARDS), this study aimed to evaluate the cellular immune responses in survivors and non-survivors of COVID-19. Methods: A total of 36 paired clinical samples of bronchoalveolar lavage fluid (BALF) mononuclear cells (BALF-MC) and peripheral blood mononuclear cells (PBMC) were collected from 18 SARS-CoV-2-infected subjects admitted to the intensive care unit (ICU) of the Policlinico Umberto I, Sapienza University Hospital in Rome (Italy) for severe interstitial pneumonia. The frequencies of monocytes (total, classical, intermediate and non-classical) and Natural Killer (NK) cell subsets (total, CD56bright and CD56dim), as well as CD4+ and CD8+ T cell subsets [naïve, central memory (TCM) and effector memory (TEM)], and those expressing CD38 and/or HLADR were evaluated by multiparametric flow cytometry. Results: Survivors with CARDS exhibited higher frequencies of classical monocytes in blood compared to non-survivors (p < 0.05), while no differences in the frequencies of the other monocytes, NK cell and T cell subsets were recorded between these two groups of patients (p > 0.05). The only exception was for peripheral naïve CD4+ T cells levels that were reduced in non-survivors (p = 0.04). An increase in the levels of CD56bright (p = 0.012) and a decrease in CD56dim (p = 0.002) NK cell frequencies was also observed in BALF-MC samples compared to PBMC in deceased COVID-19 patients. Total CD4+ and CD8+ T cell levels in the lung compartment were lower compared to blood (p = 0.002 and p < 0.01, respectively) among non-survivors. Moreover, CD38 and HLA-DR were differentially expressed by CD4+ and CD8+ T cell subsets in BALF-MC and in PBMC among SARS-CoV-2-infected patients who died from COVID-19 (p < 0.05). Conclusions: These results show that the immune cellular profile in blood and pulmonary compartments was similar in survivors and non-survivors of COVID-19. T lymphocyte levels were reduced, but resulted highly immune-activated in the lung compartment of patients who faced a fatal outcome

The SSM at 1

On February 3-4, 2016 SUERF – The European Money and Finance Forum –, Deutsche Bundesbank and Stiftung Geld und Währung jointly organized a Colloquium/Conference in Frankfurt in order to evaluate the experience with the SSM – the Single Supervisory Mechanism – during the first year of its existence. The present issue of SUERF Conference Proceedings includes a selection of papers based on the authors’ contributions to the Frankfurt event

Search of somatic GATA4 and NKX2.5 gene mutations in sporadic septal heart defects

Q3Q1Reporte de caso306-309High prevalence of somatic mutations in the cardiac transcription factor genes NKX2.5 and GATA4 have been reported in the affected cardiovascular tissue of patients with isolated cardiac septal defects, suggesting a role of somatic mutations in the pathogenesis of these congenital heart defects (CHDs). However, all somatic mutations have been identified in DNA extracted from an archive of formalin-fixed cardiac tissues. In the present study, to address the hypothesis that somatic mutations are important in isolated CHDs, we analyzed the GATA4 and NKX2.5 genes in the fresh-frozen pathologic cardiac tissue specimen and corresponding non-diseased tissue obtained from a series of 62 CHD patients, including 35 patients with cardiac septal defects and 27 with other cardiac anomalies. We identified one variant and two common polymorphisms in the NKX2.5 gene, and six variants and two common polymorphisms in the GATA4 gene. All identified variants were seen in both the fresh-frozen pathologic cardiac tissue and the corresponding non-diseased tissue, which indicates that they all were constitutional variants. The present study has identified NKX2.5 and GATA4 constitutional variants in our CHD cohort, but was unable to replicate the previously published findings of high prevalence of somatically derived sequence mutations in patients with cardiac septal defects using fresh-frozen cardiac tissues rather than formalin-fixed tissues. (C) 2011 Elsevier Masson SAS. All rights reserved

Evaluation of the prognostic value of impaired renal function on clinical progression in a large cohort of HIV-infected people seen for care in Italy

Whilst renal dysfunction, especially mild impairment (60 die;ve (Icona) Foundation Study collected between January 2000 and February 2014 with at least two creatinine values available. eGFR (CKD-epi) and renal dysfunction defined using a priori cut-offs of 60 (severely impaired) and 90 ml/min/1.73m2 (mildly impaired). Characteristics of patients were described after stratification in these groups and compared using chi-square test (categorical variables) or Kruskal Wallis test comparing median values. Follow-up accrued from baseline up to the date of the CCVD or AIDS related events or death or last available visit. Kaplan Meier curves were used to estimate the cumulative probability of occurrence of the events over time. Adjusted analysis was performed using a proportional hazards Cox regression model. We included 7,385 patients, observed for a median follow-up of 43 months (interquartile range [IQR]: 21-93 months). Over this time, 130 cerebro-cardiovascular events (including 11 deaths due to CCVD) and 311 AIDS-related events (including 45 deaths) were observed. The rate of CCVD events among patients with eGFR >90, 60-89, <60 ml/min, was 2.91 (95% CI 2.30-3.67), 4.63 (95% CI 3.51-6.11) and 11.9 (95% CI 6.19-22.85) per 1,000 PYFU respectively, with an unadjusted hazard ratio (HR) of 4.14 (95%CI 2.07-8.29) for patients with eGFR <60 ml/min and 1.58 (95%CI 1.10-2.27) for eGFR 60-89 compared to those with eGFR ≥90. Of note, these estimates are adjusted for traditional cardiovascular risk factors (e.g. smoking, diabetes, hypertension, dyslipidemia). Incidence of AIDS-related events was 9.51 (95%CI 8.35-10.83), 6.04 (95%CI 4.74-7.71) and 25.0 (95% CI 15.96-39.22) per 1,000 PYFU, among patients with eGFR >90, 60-89, <60 ml/min, respectively, with an unadjusted HR of 2.49 (95%CI 1.56-3.97) for patients with eGFR <60 ml/min and 0.68 (95%CI 0.52-0.90) for eGFR 60-89. The risk of AIDS events was significantly lower in mild renal dysfunction group even after adjustment for HIV-related characteristics. Our data confirm that impaired renal function is an important risk marker for CCVD events in the HIV-population; importantly, even those with mild renal impairment (90<60)&gt