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At least 145 records · Page 8Linked to original sources
arXiv2011

Trans-Canada Slimeways: Slime mould imitates the Canadian transport network

Slime mould Physarum polycephalum builds up sophisticated networks to transport nutrients between distant part of its extended body. The slime mould's protoplasmic network is optimised for maximum coverage of nutrients yet minimum energy spent on transportation of the intra-cellular material. In laboratory experiments with P. polycephalum we represent Canadian major urban areas with rolled oats and inoculated slime mould in the Toronto area. The plasmodium spans the urban areas with its network of protoplasmic tubes. We uncover similarities and differences between the protoplasmic network and the Canadian national highway network, analyse the networks in terms of proximity graphs and evaluate slime mould's network response to contamination.

nlin.PS↗
arXiv2011

Quantum theory of hydrogen key of point mutation in DNA

Quantum theory of hydrogen atoms distribution between two complementary nucleotide bases in DNA double helix at moment of replication has been proposed in this work. It bases on two mechanisms of proton tunneling: the Andreev-Meyerovich mechanism with spontaneous phonon radiation and the Kagan-Maximov (Flynn-Stoneham) mechanism at phonon scattering. According to the presented model, the probability of proton location in shallow potential well (point mutation form) is directly proportional to temperature. It was shown that the point mutation probability decreases with increasing replication velocity.

q-bio.OT↗
arXiv2011

Mean-field theory of collective motion due to velocity alignment

We introduce a system of self-propelled agents (active Brownian particles) with velocity alignment in two spatial dimensions and derive a mean-field theory from the microscopic dynamics via a nonlinear Fokker-Planck equation and a moment expansion of the probability distribution function. We analyze the stationary solutions corresponding to macroscopic collective motion with finite center of mass velocity (ordered state) and the disordered solution with no collective motion in the spatially homogeneous system. In particular, we discuss the impact of two different propulsion functions governing the individual dynamics. Our results predict a strong impact of the individual dynamics on the mean field onset of collective motion (continuous vs discontinuous). In addition to the macroscopic density and velocity field we consider explicitly the dynamics of an effective temperature of the agent system, representing a measure of velocity fluctuations around the mean velocity. We show that the temperature decreases strongly with increasing level of collective motion despite constant fluctuations on individual level, which suggests that extreme caution should be taken in deducing individual behavior, such as, state-dependent individual fluctuations from mean-field measurements [Yates {\em et al.}, PNAS, 106 (14), 2009].

cond-mat.stat-mech↗
arXiv2011

Genetic Code: Four Diversity Types of Protein Amino Acids

This paper presents, for the first time, four diversity types of protein amino acids. The first type includes two amino acids (G, P), both without standard hydrocarbon side chains; the second one four amino acids, as two pairs [(A, L), (V, I)], all with standard hydrocarbon side chains; the third type comprises the six amino acids, as three pairs [(F, Y), (H, W), (C, M)], two aromatic, two hetero aromatic and two "hetero" non-aromatic); finally, the fourth type consists of eight amino acids, as four pairs [(S, T), (D, E), (N, Q), (K, R)], all with a functional group which also exists in amino acid functional group (wholly presented: H2N-ĊH-COOH; separately: OH, COOH, CONH2, NH2). The insight into existence of four types of diversity was possible only after an insight into the existence of some very new arithmetical regularities, which were so far unknown. Also, as for showing these four types was necessary to reveal the relationships between several key harmonic structures of the genetic code (which we presented in our previous works), this paper is also a review article of the author's researches of the genetic code. By this, the review itself shows that the said harmonic structures are connected through the same (or near the same) chemically determined amino acid pairs, 10 pairs out of the 190 possible.

q-bio.OT↗
arXiv2011

The physical condition from the perspective of complexity: Application of a physical activity program for Alzheimer's disease

Alzheimer's disease is a sickness that has been studied from various areas of knowledge (biomarkers, brain structure, behavior, cognitive impairment). Our aim was to develop and to apply a protocol of programmed physical activity according to a non-linear methodology to enhance or diminish the deterioration of cognitive and motor functions of adults with this disease, using concepts of complexity theory for planning and programing the program. We evaluated 18 patients (12 women and 6 men) diagnosed with mild and moderate grade. We worked in small groups (2 people/coach), a total of 16 weeks, 5 sessions per week and 60 minutes per session. We designed a protocol that integrated work balance, joint mobility, coordination, muscular strength and metabolic efficiency. The strong point of this intervention was how to design the planning of tasks for patients. The tasks were developed in parallel to processes of evocation and cognitive association individually designed and presented in order of complexity. In all subjects studied, we found an improvement in the results obtained in the Mini-Mental State Examination screening test, test of Cricthon, Set-Test of Isaacs, Clock Drawing Test and Trail Making Test, and the evaluation test of fitness. The physical activity program designed and the methodology used, has been an adecuated tool to improve quality of life and autonomy of subjects analyzed.

physics.med-ph↗
arXiv2011

Experimental Researches of Cutaneous Melanoma Immunotherapy by Antitumor Cell-Whole GM-CSF-Producing Vaccines

Various approaches to increase efficiency of antitumor therapy by a combination of vaccinotherapy, chemotherapy and surgical excision of primary tumor nodes, and also the comparative analyses of therapeutic and preventive application of antitumoral vaccines were carried out in melanoma experimental model. It was postulated that preventive vaccination is able to prevent tumor incidence by 70 %. The combination of vaccinotherapy and surgical treatment of melanoma increases antimetastatic activity of vaccination by 43 %. We conclude the combined therapy would lead to more effective antitumor response.

q-bio.OT↗
arXiv2011

Free Final-Time Optimal Control for HIV Viral Dynamics

In this paper, we examine a well-established model for HIV wild-type infection. The algorithm for steepest descent method for fixed final-time is stated and a modified method for free final-time is presented. The first type of cost functional considered, seeks to minimize the total time of therapy. An easy implementation for this problem suggests that it can be effective in the early stages of treatment as well as for individual-based studies, due to the "hit first and hit hard" nature of optimal control. An LQR based cost functional is also presented and the solution is found using steepest descent method. It suggests that the optimal therapy must remain high until the patient shows signs of recovery after which, the therapy gradually decreases. This is in line with the biomedical philosophy. Solution to a modified problem which includes a weight for total time is approximated using the modified algorithm. It shows a considerable drop in the total period. We conclude that, a decreased and optimized therapy period can help us increase efficiency as well as the turnover rate for patient care.

math.OC↗
arXiv2011

On Programs and Genomes

We outline the global control architecture of genomes. A theory of genomic control information is presented. The concept of a developmental control network called a cene (for control gene) is introduced. We distinguish parts-genes from control genes or cenes. Cenes are interpreted and executed by the cell and, thereby, direct cell actions including communication, growth, division, differentiation and multi-cellular development. The cenome is the global developmental control network in the genome. The cenome is also a cene that consists of interlinked sub-cenes that guide the ontogeny of the organism. The complexity of organisms is linked to the complexity of the cenome. The relevance to ontogeny and evolution is mentioned. We introduce the concept of a universal cell and a universal genome.

q-bio.OT↗
arXiv2011

A pulse fishery model with closures as function of the catch: Conditions for sustainability

We present a model of single species fishery which alternates closed seasons with pulse captures. The novelty is that the length of a closed season is determined by the stock size of the last capture. The process is described by a new type of impulsive differential equations recently introduced. The main result is a fishing effort threshold which determines either the sustainability of the fishery or the extinction of the resource.

q-bio.OT↗
arXiv2011

Optimization of brain and life performance: Striving for playing at the top for the long run

In this essay written with my students and collaborators in mind, I share simple recipes that are easy and often fun to put in practice and that make a big difference in one's life. The seven guiding principles are: (1) sleep, (2) love and sex, (3) deep breathing and daily exercises, (4) water and chewing, (5) fruits, unrefined products, food combination, vitamin D and no meat, (6) power foods, (7) play, intrinsic motivation, positive psychology and will. These simple laws are based on an integration of evolutionary thinking, personal experimentation, and evidence from experiments reported in the scientific literature. I develop their rationality, expected consequences and describe briefly how to put them in practice. I hope that professionals and the broader public may also find some use for it, as I have seen already the positive impacts on some of my students.

q-bio.OT↗
arXiv2011

Neuroeconomics of suicide

Suicidal behavior is a leading cause of injury and death worldwide. Suicide has been associated with psychiatric illnesses such as depression and schizophrenia, as well as economic uncertainty, and social/cultural factors. This study proposes a neuroeconomic framework of suicide. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, and loss aversion) are predicted to be related to suicidal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, cortisol (HPA axis), nitric oxide, serum cholesterol, epinephrine, norepinephrine, gonadal hormones (e.g., estradiol and progesterone), dehydroepiandrosterone (DHEA) in brain regions such as the orbitofrontal/dorsolateral prefrontal cortex and limbic regions (e.g., the amygdala) may supposedly be related to the neuroeconomic parameters modulating the risk of suicide. The present framework puts foundations for "molecular neuroeconomics" of decision-making processes underlying suicidal behavior.

q-bio.NC↗
arXiv2011

Stress hormones predict hyperbolic time-discount rates six months later in adults

Objectives: Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association. Methods: We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/ mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined. Results: We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels. Conclusions: Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting.

q-bio.NC↗
arXiv2011

Depressive patients are more impulsive and inconsistent in intertemporal choice behavior for monetary gain and loss than healthy subjects- an analysis based on Tsallis' statistics

Depression has been associated with impaired neural processing of reward and punishment. However, to date, little is known regarding the relationship between depression and intertemporal choice for gain and loss. We compared impulsivity and inconsistency in intertemporal choice for monetary gain and loss (quantified with parameters in the q-exponential discount function based on Tsallis' statistics) between depressive patients and healthy control subjects. This examination is potentially important for advances in neuroeconomics of intertemporal choice, because depression is associated with reduced serotonergic activities in the brain. We observed that depressive patients were more impulsive and time-inconsistent in intertemporal choice action for gain and loss, in comparison to healthy controls. The usefulness of the q-exponential discount function for assessing the impaired decision-making by depressive patients was demonstrated. Furthermore, biophysical mechanisms underlying the altered intertemporal choice by depressive patients are discussed in relation to impaired serotonergic neural systems. Keywords: Depression, Discounting, Neuroeconomics, Impulsivity, Inconsistency, Tsallis' statistics

q-bio.NC↗
arXiv2011

Toward molecular neuroeconomics of obesity

Because obesity is a risk factor for many serious illnesses such as diabetes, better understandings of obesity and eating disorders have been attracting attention in neurobiology, psychiatry, and neuroeconomics. This paper presents future study directions by unifying (i) economic theory of addiction and obesity (Becker and Murphy, 1988; Levy 2002; Dragone 2009), and (ii) recent empirical findings in neuroeconomics and neurobiology of obesity and addiction. It is suggested that neurobiological substrates such as adiponectin, dopamine (D2 receptors), endocannabinoids, ghrelin, leptin, nesfatin-1, norepinephrine, orexin, oxytocin, serotonin, vasopressin, CCK, GLP-1, MCH, PYY, and stress hormones (e.g., CRF) in the brain (e.g., OFC, VTA, NAcc, and the hypothalamus) may determine parameters in the economic theory of obesity. Also, the importance of introducing time-inconsistent and gain/loss-asymmetrical temporal discounting (intertemporal choice) models based on Tsallis' statistics and incorporating time-perception parameters into the neuroeconomic theory is emphasized. Future directions in the application of the theory to studies in neuroeconomics and neuropsychiatry of obesity at the molecular level, which may help medical/psychopharmacological treatments of obesity (e.g., with sibutramine), are discussed.

q-bio.NC↗
arXiv2011

A neuroeconomic theory of bidirectional synaptic plasticity and addiction

Neuronal mechanisms underlying addiction have been attracting attention in neurobiology, economics, neuropsychiatry, and neuroeconomics. This paper proposes a possible link between economic theory of addiction (Becker and Murphy, 1988) and neurobiological theory of bidirectional synaptic plasticity (Bienenstock, Cooper, Munro, 1982) based on recent findings in neuroeconomics and neurobiology of addiction. Furthermore, it is suggested that several neurobiological substrates such as cortisol (a stress hormone), NMDA and AMPA receptors/subunits and intracellular calcium in the postsynaptic neurons are critical factors determining parameters in Becker and Murphy's economic theory of addiction. Future directions in the application of the theory to studies in neuroeconomics and neuropsychiatry of addiction and its relation to stress at the molecular level are discussed.

q-bio.NC↗
arXiv2011

Theoretical frameworks for neuroeconomics of intertemporal choice

Intertemporal choice has drawn attention in behavioral economics, econophysics, and neuroeconomics. Recent studies in mainstream economics have mainly focused on inconsistency in intertemporal choice (dynamic inconsistency); while impulsivity/impatience in intertemporal choice has been extensively studied in behavioral economics of addiction. However, recent advances in neuroeconomic and econophysical studies on intertemporal choice have made it possible to study both impulsivity and inconsistency in intertemporal choice within a unified framework. In this paper I propose the new frameworks for investigations into neuroeconomics of intertemporal choice. The importance of studying neurochemical and neuroendocrinological modulations of intertemporal choice and time-perception (e.g. serotonin, dopamine, cortisol, testosterone, and epinephrine) is emphasized.

q-bio.NC↗
arXiv2011

Systematic Approach on Differences in Avian Viral Proteins Based on Carbon Composition

The distribution of amino acid along the protein sequences plays an imperative role in facilitating different biological functions. Currently, there is insufficient scientific data, which represents the arrangement of amino acid in the proteins based on atomic composition. Our deep observational and analytical studies indicate that the distribution of carbon in the protein sequence can bring differences in the function of proteins. Until now, it is believed that carbon content elicits the hydrophobic interactions in proteins. This distinct feature classifies normal proteins and viral proteins based on the carbon content. One of the objectives of this investigation is to show the significance of carbon composition in protein structure evaluation. Since, the level of perceived benefit is likely to be high in the field of proteomics for structural analysis, the position of this paper is to prioritize only the avian viral protein sequences based on carbon content when compared with the normal protein sequences. Here, we present the evaluation of carbon along the avian protein sequence in order to show the differences in the distribution of carbon using the software technology. The evaluation results provide a deep view in to the molecular structure of avian viral protein, which can further enable the progress of research in the proteomics domain based on carbon classification. This systematic approach in computing carbon level of avian viruses aim towards the benefit of individual, regional and global health in addition to opening of further effective research on avian viral protein based on the aforementioned results

q-bio.OT↗