Using Synchronous Boolean Networks to Model Several Phenomena of Collective Behavior

In this paper, we propose an approach for modeling and analysis of a number of phenomena of collective behavior. By collectives we mean multi-agent systems that transition from one state to another at discrete moments of time. The behavior of a member of a collective (agent) is called conforming if the opinion of this agent at current time moment conforms to the opinion of some other agents at the previous time moment. We presume that at each moment of time every agent makes a decision by choosing from the set (where 1-decision corresponds to action and 0-decision corresponds to inaction). In our approach we model collective behavior with synchronous Boolean networks. We presume that in a network there can be agents that act at every moment of time. Such agents are called instigators. Also there can be agents that never act. Such agents are called loyalists. Agents that are neither instigators nor loyalists are called simple agents. We study two combinatorial problems. The first problem is to find a disposition of instigators that in several time moments transforms a network from a state where the majority of simple agents are inactive to a state with the majority of active agents. The second problem is to find a disposition of loyalists that returns the network to a state with the majority of inactive agents. Similar problems are studied for networks in which simple agents demonstrate the contrary to conforming behavior that we call anticonforming. We obtained several theoretical results regarding the behavior of collectives of agents with conforming or anticonforming behavior. In computational experiments we solved the described problems for randomly generated networks with several hundred vertices. We reduced corresponding combinatorial problems to the Boolean satisfiability problem (SAT) and used modern SAT solvers to solve the instances obtained.     

Role of antigen-nonspecific suppressors occurring in stress in the pathogenesis of Langat virus infection in mice

Stress factors of different nature activate antigen-nonspecific suppressors inhibiting different mechanisms of immune response in mice. The adoptive transfer of the population of immunocompetent cells containing stress-induced suppressors to mice infected with Langat virus has been found to lead to the activation of asymptomatic infection. The data obtained in this investigation indicate that the above-mentioned mechanism of the development of antigen-nonspecific immune deficiency is of importance in the pathogenesis of viral infections in man and it explains the onset of diseases (or their aggravation) under the conditions of stress.     

Ortho-Phthalic Acid Esters Suppress the Phytopathogen Capability for Biofilm Formation

This is the first study demonstrating that ortho-phthalic acid esters, dibutylphthalate (DBP) and di-(2-ethylhexyl)-o-phthalate (DEHP), inhibit the ability to form biofilms of the biotrophic pathogen Clavibacter michiganensis ssp. sepedonicus and Pectobacterium carotovorum ssp. carotovorum necrotroph. Inhibition of biofilm formation depends on the DBP and DEHP concentrations.     

Contribution of crop model structure,parameters and climate projections to uncertainty in climate change impact assessments

Climate change impact assessments are plagued with uncertainties from many sources, such as climate projections or the inadequacies in structure and parameters of the impact model. Previous studies tried to account for the uncertainty from one or two of these. Here, we developed a triple‐ensemble probabilistic assessment using seven crop models, multiple sets of model parameters and eight contrasting climate projections together to comprehensively account for uncertainties from these three important sources. We demonstrated the approach in assessing climate change impact on barley growth and yield at Jokioinen, Finland in the Boreal climatic zone and Lleida, Spain in the Mediterranean climatic zone, for the 2050s. We further quantified and compared the contribution of crop model structure, crop model parameters and climate projections to the total variance of ensemble output using Analysis of Variance (ANOVA). Based on the triple‐ensemble probabilistic assessment, the median of simulated yield change was ?4% and +16%, and the probability of decreasing yield was 63% and 31% in the 2050s, at Jokioinen and Lleida, respectively, relative to 1981–2010. The contribution of crop model structure to the total variance of ensemble output was larger than that from downscaled climate projections and model parameters. The relative contribution of crop model parameters and downscaled climate projections to the total variance of ensemble output varied greatly among the seven crop models and between the two sites. The contribution of downscaled climate projections was on average larger than that of crop model parameters. This information on the uncertainty from different sources can be quite useful for model users to decide where to put the most effort when preparing or choosing models or parameters for impact analyses. We concluded that the triple‐ensemble probabilistic approach that accounts for the uncertainties from multiple important sources provide more comprehensive information for quantifying uncertainties in climate change impact assessments as compared to the conventional approaches that are deterministic or only account for the uncertainties from one or two of the uncertainty sources.     

Hyphal growth and colony expansion

Several generations of soil microbiologists and plant pathologists have attempted to unravel the microbial composition, population dynamics and various life-sustaining processes in the soil. However, until recently, this basic resource for plant growth and nutrient recycling has to a large extent remained a black box. Studies have been made of the behavior of individual microorganisms or their population dynamics, but the relationship between the growth of individual organisms or parts of organisms (such as fungal hyphae) and that of populations and communities has been largely unknown. In particular, the spread of fungal colonies in soil has been an enigma, but now Bailey et al . (pp. 000–000 in this issue) have clearly demonstrated that spatial behavior of Rhizoctonia colonies can switch from finite to invasive expansion dependent on the non-linear relationship between the distance among substrate particles and the probability of colonization.     

Efficiency of photostimulation controlled by subject’s EEG decreases under the conditions of feedback delay

One of the central problems in the study of brain–computer interface and the processes of operant conditioning is the optimal organization of feedback signals. In this paper we have analyzed the question about comparative efficiency of immediate or 2.56-s delayed presentation of feedback signals as photic stimulation automatically controlled by subject’s electroencephalogram (EEG). Strictly controlled experiments showed a significant increase in EEG power and positive shifts in subjective characteristics only under the minimum feedback delay, i.e., in cases where photic stimuli are controlled directly by the current EEG characteristics of the subjects.     

Involvement of the intracellular regulatory systems in the adaptive effect of short-term anoxia in vitro]

Moderate long-term activation of intracellular regulatory system (IRS) was found to be manifested as an increase in the bound calcium content and intensity of the phosphoinositide metabolism following a 30-minute re-oxygenation in the rat olfactory cortex perfused slices. The perfusate induced a similar activation in intact slices-recipients. Long-term anoxia induced a biphasic NMDA-dependent increase in intracellular free Ca2+ and pathogenic hyperactivity of the IRS. The pathogenic events could be prevented by preconditioning of the slices by either short-term anoxia (STA) or post-STA donor perfusate.     

Immunogenicity of recombinant analog of antitumor protein lactaptin

Therapeutic monoclonal antibodies and recombinant proteins including cytokines are commonly used in the treatment of cancer and inflammatory diseases. In most cases, these protein-based drugs exhibit a high therapeutic efficacy, which is unfortunately frequently associated with a variety of side effects. We have investigated the in vitro and in vivo immunogenicity of recombinant antitumor protein lactaptin (RL2). Based on the qRT-PCR analysis, we have shown that, in MDA-MB-231 human breast adenocarcinoma cells, RL2 suppresses the NF-kB signaling cascade that regulates the reactions of innate immunity. RL2 inhibits the expression of the CXCL1 protein and apoptosis inhibitor A20 and enhances expression of IkB, NF-kB repressor. The ELISA method has been used to evaluate the antibody titer in the blood of mice, which received single and triple intravenous or intraperitoneal injections of RL2. The multiplex immunoassay of 23 cytokines in the mice blood has shown that the RL2 injections lead to a slight increase in the levels of systemic pro-inflammatory cytokine interleukin-5 (IL-5) and keratinocyte chemoattractant (KC), a homologue of human macrophage inflammatory protein-1 (MIP-1). These observations indicate the low immunogenicity of the recombinant lactaptin analog, which can be considered to be a potential molecular drug candidate for further clinical development.