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The paper contributes to unveil how drivers—either human or not—may lose control of road vehicles after a disturbance. First, a simple vehicle-and-driver model is considered: Its motion is characterized by the existence of limit cycles whose amplitude depend on vehicle forward velocity (both oversteering and understeering vehicles may exibit this property). Such limit cycles are originated by a Hopf bifurcation occurring at a relatively high vehicle forward velocity. A mathematical proof of the existence of Hopf bifurcations is given. The existence of Hopf bifurcations and saddle limit cycles is confirmed by experimental tests performed by a dynamic driving simulator with a complex vehicle model and human in the loop. By a Zubov method, a Lyapunov function is derived to compute the region of asymptotic stability for the simple vehicle-and-driver model. A necessary and sufficient condition is derived for global asymptotic stability. Such a condition refers to the variation of the kinetic energy which must vanish at the end of the disturbed motion. This occurrence has been detected at the driving simulator too. Just a single stable equilibrium has been found inside the domain of attraction in all of the examined cases. [ABSTRACT FROM AUTHOR]

Objective: Nintedanib (NIN) is an antifibrotic drug approved to slow the progression of idiopathic pulmonary fibrosis (IPF) and systemic sclerosis-related interstitial lung disease (SSc-ILD). NIN can frequently cause gastrointestinal adverse effects. We aimed to investigate the NIN safety profile in a real life setting, comparing IPF and SSc-ILD patients and evaluating the strategies adopted to manage NIN adverse effects. Methods: Patients taking NIN for IPF or SSc-ILD were enrolled. Alongside epidemiological and disease-specific data, the period of NIN use and the need for dosage reduction and/or interruption were investigated. Particular attention was paid to possible adverse effects and strategies adopted to manage them. Results: Twenty-seven SSc-ILD and 82 IPF patients were enrolled. No significant differences emerged between the two cohorts regarding the frequency of any possible adverse effect. Although the rates of NIN dosage reduction or interruption were similar between the two subgroups, SSc-ILD presented a mean period before NIN dosage reduction and NIN interruption significantly shorter than IPF (3 ± 2.6 vs 10.5 ± 8.9 months—p < 0.001 and 2.3 ± 0.5 vs 10.3 ± 9.9 months—p = 0.008, respectively). Several different strategies were tried to manage NIN adverse effects: especially in SSc-ILD, the variable combination of diet adjustment set by a nutritionist, probiotics and diosmectite was ultimately successful in maintaining patients on an adequate dose of NIN. Conclusion: We presented data on the NIN safety profile in a real life setting, which was similar between SSc-ILD and IPF. A combination of multiple managing strategies and dose adjustment appears essential to cope optimally with NIN adverse effects. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the performance of oropharyngoesophageal scintigraphy (OPES) in the assessment of dysphagia in patients with systemic sclerosis (SSc), and to compare OPES results with those of barium esophagogram. Methods: Adult SSc patients who underwent OPES for the assessment of dysphagia were enrolled. OPES was performed with both liquid and semisolid boluses and provided information regarding oropharyngeal transit time, esophageal transit time (ETT), oropharyngeal retention index (OPRI), esophageal retention index (ERI), and site of bolus retention. Barium esophagogram results were also collected. Results: Fifty-seven SSc patients (87.7% female, mean age 57.7 years) with dysphagia were enrolled. OPES identified at least one alteration in each patient and findings were generally worse for the semisolid bolus. Esophageal motility was widely impaired with 89.5% of patients with an increased semisolid ERI, and middle-lower esophagus was the most frequent site of bolus retention. However, oropharyngeal impairment was highlighted by widespread increased OPRI, especially in anti-topoisomerase I positivity. Older patients and with longer disease duration presented slower semisolid ETT (p = 0.029 and p = 0.002, respectively). Eleven patients with dysphagia had a negative barium esophagogram: all of them presented some alterations in OPES parameters. Conclusion: OPES revealed a marked SSc esophageal impairment, in terms of both slowed transit time and increased bolus retention, but also shed light on oropharyngeal swallowing alterations. OPES showed high sensitivity, being able to detect swallowing alterations in dysphagic patients with negative barium esophagogram. Therefore, the use of OPES for the assessment of SSc-related dysphagia in clinical practice should be promoted. [ABSTRACT FROM AUTHOR]

Many processes in nature are the result of many coupled individual subsystems (like population dynamics or neurosystems). Not always such systems exhibit simple stable behaviors that in the past science has mostly focused on. Often, these systems are characterized by bursts of seemingly stochastic activity, interrupted by quieter periods. The hypothesis is that the presence of a strong deterministic ingredient is often obscured by the stochastic features. We test this by modeling classically stochastic considered real-world data from both, the stochastic as well as the deterministic approaches to find that the deterministic approach's results level with those from the stochastic side. Moreover, the deterministic approach is shown to reveal the full dynamical systems landscape, which can be exploited for steering the dynamics into a desired regime. [ABSTRACT FROM AUTHOR]

Researchers worldwide are expected to design and develop agroecological systems to address major challenges such as increasing biotic pressure and climate change. But to design effective innovations, researchers should integrate new cropping techniques into wider agricultural systems such as cropping systems, innovative farms, alternative food systems, or multifunctional landscapes. This integration requires a long process of exploration in which the object under design can transform and shift to a different organisational scale. In this article, we wish to introduce a new analytical framework highlighting the systemic mechanisms involved in the scale transformations of design objects along agroecological design processes. We conceptualise an agroecological design process as a non-linear unpredictable process in which four components—a science consortium, non-scientific actors in the field, a problem situation and a design object—interact, and co-evolve through time. The scale transformations of the design objects and their drivers are the results of interactions and knowledge flows between these four components. This analytical framework was tested and further elaborated through ex-post analysis of design processes in three contrasting case studies in the context of tropical horticulture. Data were collected through literature review, interviews, and focus group discussions with the researchers involved in the three design processes. Future design methods should take full account of the lengthy, non-linear, and transformational nature of agroecological design processes and the coexistence of different types of knowledge—holistic vs. reductionist, ecosystem focused vs. human-system focused—which can interconnect and nourish each other. [ABSTRACT FROM AUTHOR]

We propose a class of locally Lipschitz functions with piecewise structure for use as Lyapunov functions for hybrid dynamical systems. Subject to some regularity of the dynamics, we show that Lyapunov inequalities can be checked only on a dense set and thus we avoid checking them at points of nondifferentiability of the Lyapunov function. Connections to other classes of locally Lipschitz or piecewise regular functions are also discussed, and applications to hybrid dynamical systems are included. [ABSTRACT FROM AUTHOR]

Chlordecone, applied on soils until 1993 to control banana weevil, has polluted water resources in the French West Indies for more than 40 years. At the watershed scale, chlordecone applications were not homogenous, generating a spatial heterogeneity of the pollution. The roles of climate, hydrology, soil, agronomy, and geology on watershed functioning generate a temporal heterogeneity of the pollution. This study questions the interactions between practices and the environment that induce such variability. We analyzed hydrological and water pollution datasets from a 2-year monitoring program on the Galion watershed in Martinique (French West Indies). We conjointly analyzed (i) weekly chlordecone (CLD) concentration monitored on 3 river sampling sites, (ii) aquifer piezometric dynamics and pollutions, and (iii) agricultural practices on polluted soils. Our results showed that chlordecone pollution in surface waters are characterized by annual trends and infra-annual variations. Aquifers showed CLD concentration 10 times higher than surface water, with CLD concentration peaks during recharge events. We showed strong interactions between rainfall events and practices on CLD pollution requiring a systemic management approach, in particular during post-cyclonic periods. Small sub-watershed with high CLD pollution appeared to be a substantial contributor to CLD mass transfers to the marine environment via rivers and should therefore receive priority management. We suggest increasing stable organic matter return to soil as well as external input of organic matter to reduce CLD transfers to water. We identified hydrological conditions—notably drying periods—and tillage as the most influential factors on CLD leaching. In particular, tillage acts on 3 processes that increases CLD leaching: organic matter degradation, modification of water paths in soil, and allophane clay degradation. [ABSTRACT FROM AUTHOR]

The COVID-19 epidemic hit Italy particularly hard, yielding the implementation of strict national lockdown rules. Previous modelling studies at the national level overlooked the fact that Italy is divided into administrative regions which can independently oversee their own share of the Italian National Health Service. Here, we show that heterogeneity between regions is essential to understand the spread of the epidemic and to design effective strategies to control the disease. We model Italy as a network of regions and parameterize the model of each region on real data spanning over two months from the initial outbreak. We confirm the effectiveness at the regional level of the national lockdown strategy and propose coordinated regional interventions to prevent future national lockdowns, while avoiding saturation of the regional health systems and mitigating impact on costs. Our study and methodology can be easily extended to other levels of granularity to support policy- and decision-makers. An ongoing global debate concerns effective and sustainable lockdown release strategies in the current pandemic. Here, the authors implement a network model at healthcare-relevant spatial scale to show that coordinated local strategies can be effective in containing further resurgence of the disease. [ABSTRACT FROM AUTHOR]

Real-world systems in epidemiology, social sciences, power transportation, economics and engineering are often described as multilayer networks. Here we first define and compute the symmetries of multilayer networks, and then study the emergence of cluster synchronization in these networks. We distinguish between independent layer symmetries, which occur in one layer and are independent of the other layers, and dependent layer symmetries, which involve nodes in different layers. We study stability of the cluster synchronous solution by decoupling the problem into a number of independent blocks and assessing stability of each block through a Master Stability Function. We see that blocks associated with dependent layer symmetries have a different structure to the other blocks, which affects the stability of clusters associated with these symmetries. Finally, we validate the theory in a fully analog experiment in which seven electronic oscillators of three kinds are connected with two kinds of coupling. Complex systems in the real world are often characterized by connected patterns interacting between each other in multiple ways. Here, Della Rossa et al. describe a general method to determine symmetries in multilayer networks and then relate them to different synchronization modes that the networks can exhibit. [ABSTRACT FROM AUTHOR]

The stability of the straight ahead running motion of automobiles is studied with proper theoretical tools pertaining to bifurcation theory. The study is both theoretical and experimental. Four theoretical models have been employed. They refer, respectively, to one simple car model, one simple driver model, one complex car model and one complex driver model. The existence of bifurcations, namely Hopf bifurcations, is found for both the simple car/simple driver model combination and for the complex car/complex driver model combination. The experimental study refers to the employment of a driving simulator in which a human driver controls the complex car model. At the driving simulator, bifurcations are found which correspond to the ones predicted either with the simple car/simple driver model combination or the complex car/complex driver model combination. At the driving simulator a chaotic motion is found, after a subcritical Hopf bifurcation has occurred. Apparently, for the first time in the sector of vehicle system dynamics, the actual existence of bifurcations and chaos has been shown for a real system with a human driver in-the-loop. The driving simulator does not seem introducing factors affecting sensibly bifurcations, so the bifurcations that have been found appear to be real, i.e. bifurcations could be found in an actual car running straight ahead. [ABSTRACT FROM AUTHOR]

Some chemical herbicides used by farmers in Martinique contaminate rivers. Agroecological innovations exist, some of which are known by the stakeholders but are not systematically used at the scale of the watersheds concerned. Our hypothesis is that the sociotechnical agricultural supply chain system built over the last 30 years restricts innovations for herbicide use in weed management systems, blocking the sustainable transition of territories. The sociotechnical system theory was chosen as the analysis framework to identify obstacles in supply chains. As the issue cut across the supply chains at the scale of the territory, this framework was completed, for the first time, by a study of the existing links between supply chain innovation strategies and the territory through its spatial, organisational and conceptual dimensions. Interviews with supply chain actors and a review of the grey literature were analysed using this framework. We show that the development of innovations, their type and the network of actors producing them were defined within each supply chain, according to their own objectives, with few exchanges at all levels of the territory. The efficiency of such development depended on the extent to which the supply chains are structured and, particularly, on their degree of integration and the strength of relationships between stakeholders. Indeed, watershed scale objectives are not taken into consideration in changes of practice. In this way, we identified lock-in constraining innovations design taking into account the objectives of the impact area (watershed) across supply chains for the first time. [ABSTRACT FROM AUTHOR]

Objective: Digital ulcers (DUs) represent one major burden for patients with systemic sclerosis (SSc). The objectives of our study were to evaluate blood flow in SSc-DUs with laser speckle contrast analysis (LASCA) and to correlate the skin perfusion to clinical and laboratory data. Methods: Forty DUs in 31 consecutive patients with SSc according to 2013 ACR/EULAR criteria (20 with limited cutaneous disease, 3 males) were prospectively examined with LASCA. Clinical and laboratory data were collected at the same time. DUs were classified according to clinical features and presence of infection. Results: At LASCA analysis, patients with diffuse SSc had lower mean values of blood flow compared with those with limited disease at the finger affected by DUs (88.80 vs 44.40, p = 0.036) and at the periulcer area (p = 0.041). The presence of infection was associated to a higher flow at the finger with DU (103.02 vs 58.05 p = 0.04), at the level of ulcer (217.63 vs 67.15, p < 0.001), and at the periulcer area (p = 0.001). The ratio between the blood flow at the ulcer area and the finger base (UA/FB) showed a bimodal trend in patients with infected DUs and in those without infections. Infection was positive correlated to the time of healing (HT) (r = 0.648, p = 0.023), while in DUs without infection a negative correlation to HT (r = − 0.46, p = 0.015) was identified. Conclusions: This study demonstrates for the first time that the UA/FB ratio may predict the healing time of DUs in SSc patients and may be crucial for the prognostic stratification of patients. Infection remains one of the main predictors of DU healing. Key Points • The prognostic value of laser speckle contrast analysis (LASCA) in patients with digital ulcers (DUs) in systemic sclerosis remains to be clarified. • LASCA may be able to predict the haling time of the digital ulcers. • The presence of infection of the wound bed may greatly influence the LASCA parameters and the healing time of the digital ulcer. [ABSTRACT FROM AUTHOR]

Vasculopathy is a crucial feature of systemic sclerosis (SSc), and Raynaud's phenomenon (RP) and digital ulcers (DU) have a deep impact on the quality of patients' life. The management of vascular disease can be challenging for the clinician because of the suboptimal tolerability of the treatments and lack of consensus on the best therapeutic approach. Intravenous iloprost, a synthetic analogue of prostacyclin, is broadly used for the treatment of RP and ischemic ulcers secondary to SSc. However, no standardized protocol on iloprost use is currently available and, consequently, the management of this treatment is largely based on the experience of each single center. The PROSIT project is an observational, multicenter study aiming to investigate the current treatments for SSc vasculopathy, the use of prostanoids, with special regard to iloprost, and the perception of the treatment from a patient's perspective. The study was conducted on a cohort of 346 patients from eight Italian centers and included a structured survey addressed to physicians, data collected from patient's medical records and two patient-administered questionnaires assessing the level of satisfaction, tolerability and perception of the efficacy of Iloprost. PROSIT data confirmed that in the contest of SSc iloprost represents the first-line choice for the management of severe RP and DU. Moreover, it is a well-tolerated treatment as reported by patients' experience. Although a standard protocol for the treatment of SSc-related vasculopathy is lacking, PROSIT study identified different therapeutic approaches largely supported by tertiary Italian centers. Further studies are needed in order to optimize the best treatment for SSc vascular diseases, in particular to improve the best iloprost schedule management. [ABSTRACT FROM AUTHOR]

In this paper, we propose and analyze a new descriptive model of armed conflicts among N groups. The model is composed of N2 ordinary differential equations, with 3(N2+N) constant parameters that describe military characteristics and recruitment policies, ranging from pure defensivism to pure fanaticism. The results are only preliminary, but point out interesting (though not very surprising) properties: periodic coexistence is possible, and multiple attractors can exist; governmental groups cannot go extinct if they are highly defensivist, and rebels cannot be eradicated if they are highly fanatic. Shocks due to interventions of short duration of an external army can stabilize/destabilize the system and/or eradicate some group, and the same holds true for small structural changes. Other more subtle questions concerning, for example, the existence of chaotic regimes and the systematic evaluation of the role of strategic factors like power, intelligence, and fanaticism, remain open and require further research. [ABSTRACT FROM AUTHOR]

In this paper, we show that even an extremely simple nonlinear vehicle and driver model can show complex behaviors, like multi-stability and sensible dependence on the initial condition. The mechanical model of the car has two degrees of freedom, and the related equations of motion contain the nonlinear characteristics of the tires. The driver model is described by a single (nonlinear) equation, characterized by three parameters that describe how the driver steers the vehicle. Namely such parameters are the gain (steering angle per lateral deviation from desired path), the preview distance, and the reaction time delay. Bifurcation analysis is adopted to characterize straight ahead motion at different speeds, considering separately the two cases of understeering or oversteering cars. In the first case, we show that at suitable speeds the model can have three different attracting oscillating trajectories on which the system can work and that are reached due to different disturbances. In the second case, we confirm that instability arises if the forward speed is too high. The final results of the paper, bifurcation diagrams, can be used for many considerations critical both from the theoretical and from the practical viewpoints. [ABSTRACT FROM AUTHOR]

Muscular involvement is common during systemic vasculitides, such as polyarteritis nodosa. However, in rare cases, muscular involvement can be the only clinically evident feature of the disease. The clinical pattern of isolated muscular vasculitis may mimic several other inflammatory muscle disorders, such as idiopathic inflammatory myositis, and may represent a challenge in differential diagnosis. Herewith, we present two clinical cases as examples of peculiar clinical and histopathological characteristics of isolated muscular vasculitis. Our patients were successfully treated with steroids and immunosuppressive agents. Moreover, we provide a review of the recent existing medical literature. Our cases suggest the importance of performing muscle biopsy in patients with muscular symptoms to guide the diagnosis and the treatment. [ABSTRACT FROM AUTHOR]

We show that when selection is extreme-the fittest strategy always reproduces or is imitated-the unequivalence between the possible evolutionary game scenarios in finite and infinite populations resolves, in the sense that the three generic outcomes-dominance, coexistence, and mutual exclusion-emerge in well-mixed populations of any size. We consider the simplest setting of a 2-player-2-strategy symmetric game and the two most common microscopic definitions of strategy spreading-the frequency-dependent Moran process and the imitation process by pairwise comparison-both in the case allowing any intensity of selection. We show that of the seven different invasion and fixation scenarios that are generically possible in finite populations-fixation being more or less likely to occur and rapid compared to the neutral game-the three that are possible in large populations are the same three that occur for sufficiently strong selection: (1) invasion and fast fixation of one strategy; (2) mutual invasion and slow fixation of one strategy; (3) no invasion and no fixation. Moreover (and interestingly), in the limit of extreme selection 2 becomes mutual invasion and no fixation, a case not possible for finite intensity of selection that better corresponds to the deterministic case of coexistence. In the extreme selection limit, we also derive the large population deterministic limit of the two considered stochastic processes. [ABSTRACT FROM AUTHOR]

Uncertainty quantification for geomechanical and reservoir predictions is in general a computationally intensive problem, especially if a direct Monte Carlo approach with large numbers of full-physics simulations is used. A common solution to this problem, well-known for the fluid flow simulations, is the adoption of surrogate modeling approximating the physical behavior with respect to variations in uncertain parameters. The objective of this work is the quantification of such uncertainty both within geomechanical predictions and fluid-flow predictions using a specific surrogate modeling technique, which is based on a functional approach. The methodology realizes an approximation of full-physics simulated outputs that are varying in time and space when uncertainty parameters are changed, particularly important for the prediction of uncertainty in vertical displacement resulting from geomechanical modeling. The developed methodology has been applied both to a subsidence uncertainty quantification example and to a real reservoir forecast risk assessment. The surrogate quality obtained with these applications confirms that the proposed method makes it possible to perform reliable time-space varying dependent risk assessment with a low computational cost, provided the uncertainty space is low-dimensional. [ABSTRACT FROM AUTHOR]

We present a methodology that allows conditioning the spatial distribution of geological and petrophysical properties of reservoir model realizations on available production data. The approach is fully consistent with modern concepts depicting natural reservoirs as composite media where the distribution of both lithological units (or facies) and associated attributes are modeled as stochastic processes of space. We represent the uncertain spatial distribution of the facies through a Markov mesh (MM) model, which allows describing complex and detailed facies geometries in a rigorous Bayesian framework. The latter is then embedded within a history matching workflow based on an iterative form of the ensemble Kalman filter (EnKF). We test the proposed methodology by way of a synthetic study characterized by the presence of two distinct facies. We analyze the accuracy and computational efficiency of our algorithm and its ability with respect to the standard EnKF to properly estimate model parameters and assess future reservoir production. We show the feasibility of integrating MM in a data assimilation scheme. Our methodology is conducive to a set of updated model realizations characterized by a realistic spatial distribution of facies and their log permeabilities. Model realizations updated through our proposed algorithm correctly capture the production dynamics. [ABSTRACT FROM AUTHOR]

The problem of the frequency of sexual intercourse in couples was investigated for the first time with a purely conceptual model. The model, based on a few axioms involving the notions of sexual appetite and erotic potential, was composed of two ordinary differential equations which turn out to be the same as those proposed almost one century ago in epidemiology. The model can be used to discuss the possibility of estimating strategic parameters from real data, as well as to criticize the rule of 'the beans in the jar' proposed by Martin (). [ABSTRACT FROM AUTHOR]

The performance of the Ensemble Kalman Filter method (EnKF) depends on the sample size compared to the dimension of the parameters space. In real applications insufficient sampling may result in spurious correlations which reduce the accuracy of the filter with a strong underestimation of the uncertainty. Covariance localization and inflation are common solutions to these problems. The Ensemble Square Root Filters (ESRF) is also better to estimate uncertainty with respect to the EnKF. In this work we propose a method that limits the consequences of sampling errors by means of a convenient generation of the initial ensemble. This regeneration is based on a Stationary Orthogonal-Base Representation (SOBR) obtained via a singular value decomposition of a stationary covariance matrix estimated from the ensemble. The technique is tested on a 2D single phase reservoir and compared with the other common techniques. The evaluation is based on a reference solution obtained with a very large ensemble (one million members) which remove the spurious correlations. The example gives evidence that the SOBR technique is a valid alternative to reduce the effect of sampling error. In addition, when the SOBR method is applied in combination with the ESRF and inflation, it gives the best performance in terms of uncertainty estimation and oil production forecast. [ABSTRACT FROM AUTHOR]

Increasing evidence has been accumulated for treating rheumatoid arthritis (RA) with TNF-α blocking agents. The formulation and definition of an early indicator of patient's reactivity during therapy may be extremely simplified by a mathematical model of clinical response. We analyzed the most significant clinical and laboratory parameters of response of 35 homogeneous patients (30 women, 5 men mean age ± SD: 52.31 ± 12.30 years) treated with adalimumab 40 mg every 2 weeks associated with methotrexate (MTX) 10-15 mg/week and with a stable dosage of steroids for 30 weeks. The over time trend of the studied parameters showed a linear response, which has allowed the realization of a simple mathematical model. The formula derived from this mathematical model was then applied and therefore validated in a group of 121 patients previously treated with several anti-TNF-alpha agents for at least 6 months. We drafted a mathematical model (early response indicator, ERI) that, by using a simple calculation, allows us to identify a high percentage of responder patients after only 2 weeks of treatment. ERI identified a high percentage (88%) of patients responding after only 2 weeks, as was confirmed at weeks 30; the use of ERI calculation after 6 weeks increases the proportion of responding patients to 92% with a percentage of false negatives of only 12%. ERI could be a useful tool to early differentiate the responder from the non-responder patients. [ABSTRACT FROM AUTHOR]

In this paper we present an extension of the ensemble Kalman filter (EnKF) specifically designed for multimodal systems. EnKF data assimilation scheme is less accurate when it is used to approximate systems with multimodal distribution such as reservoir facies models. The algorithm is based on the assumption that both prior and posterior distribution can be approximated by Gaussian mixture and it is validated by the introduction of the concept of finite ensemble representation. The effectiveness of the approach is shown with two applications. The first example is based on Lorenz model. In the second example, the proposed methodology combined with a localization technique is used to update a 2D reservoir facies models. Both applications give evidence of an improved performance of the proposed method respect to the EnKF. [ABSTRACT FROM AUTHOR]

Mixed cryoglobulinemia remains a major challenge to the clinician, both in terms of diagnosis and treatment. The discovery of its association with the hepatitis C virus has helped to shed light on the mechanisms of its pathogenesis and on how this complex disease might be managed. In this respect, interferon represents the first attempt to take an etiological approach to the treatment of a virus-related, immune-mediated human disease. Its uneven results, however, have on the one hand raised hopes that a final solution to the problem may be near, and at the same time underlined the fact that we probably have a long way to go before our goal is actually reached. [ABSTRACT FROM AUTHOR]

The presence of synchronized clusters in neuron networks is a hallmark of information transmission and processing. Common approaches to study cluster synchronization in networks of coupled oscillators ground on simplifying assumptions, which often neglect key biological features of neuron networks. Here we propose a general framework to study presence and stability of synchronous clusters in more realistic models of neuron networks, characterized by the presence of delays, different kinds of neurons and synapses. Application of this framework to two examples with different size and features (the directed network of the macaque cerebral cortex and the swim central pattern generator of a mollusc) provides an interpretation key to explain known functional mechanisms emerging from the combination of anatomy and neuron dynamics. The cluster synchronization analysis is carried out also by changing parameters and studying bifurcations. Despite some modeling simplifications in one of the examples, the obtained results are in good agreement with previously reported biological data. [ABSTRACT FROM AUTHOR]

: HCV infection has been associated with a broad spectrum of extrahepatic manifestations. In some of these, such as mixed cryoglobulinaemia (MC), the association is firmly established, whereas in others, such as polyarteritis nodosa (PAN), it is anecdotal; in fact, in this disorder the importance of the association is controversial, since it seems to be related to the frequent coinfection of HBV and HCV. The pathogenesis of MC and PAN is far from clear, but recent developments have added a plethora of information on the mechanisms underlying these disorders. Although both could be induced by a viral infection, the pathophysiological processes underlying the two diseases are different. We describe the occurrence in the same patient of HBV-related PAN and HCV-related MC. [ABSTRACT FROM AUTHOR]

Polymyositis is a systemic autoimmune disorder characterised by proximal muscle weakness which most frequently involves the limbs, neck and trunk. Alpha interferon is an antiviral molecule with well-known immunomodulatory and antiproliferative effects, but its use is often associated with a variety of side effects, in particular autoimmune phenomena. We report the occurrence of polymyositis during treatment with alpha-interferon in a patient affected by malignant melanoma. Indirect evidence suggests that in this case the patient's myositis was not linked to her neoplasia, since the melanoma was confirmed to be in remission both at the time of the diagnosis of the muscle disease and again after more than one year of follow-up. [ABSTRACT FROM AUTHOR]

Since M. A. Nowak & R. May's (1992) influential paper, limiting each agent's interactions to a few neighbors in a network of contacts has been proposed as the simplest mechanism to support the evolution of cooperation in biological and socio-economic systems. The network allows cooperative agents to self-assort into clusters, within which they reciprocate cooperation. This (induced) network reciprocity has been observed in several theoreticalmodels and shown to predict the fixation of cooperation under a simple rule: the benefit produced by an act of cooperation must outweigh the cost of cooperating with all neighbors. However, the experimental evidence among humans is controversial: though the rule seems to be confirmed, the underlying modeling assumptions are not. Specifically, models assume that agents update their strategies by imitating better performing neighbors, even though imitation lacks rationality when interactions are far from all-to-all. Indeed, imitation did not emerge in experiments. What did emerge is that humans are conditioned by their own mood and that, when in a cooperative mood, they reciprocate cooperation. To help resolve the controversy, we design a model in which we rationally confront the two main behaviors emerging from experiments—reciprocal cooperation and unconditional defection—in a networked prisoner's dilemma. Rationality is introduced by means of a predictive rule for strategy update and is bounded by the assumed model society. We show that both reciprocity and a multi-step predictive horizon are necessary to stabilize cooperation, and sufficient for its fixation, provided the game benefit-to-cost ratio is larger than a measure of network connectivity. We hence rediscover the rule of network reciprocity, underpinned however by a different evolutionary mechanism. [ABSTRACT FROM AUTHOR]