Flame front propagation IV: Random Noise and Pole-Dynamics in Unstable Front Propagation II

The current paper is a corrected version of our previous paper arXiv:adap-org/9608001. Similarly to previous version we investigate the problem of flame propagation. This problem is studied as an example of unstable fronts that wrinkle on many scales. The analytic tool of pole expansion in the complex plane is employed to address the interaction of the unstable growth process with random initial conditions and perturbations. We argue that the effect of random noise is immense and that it can never be neglected in sufficiently large systems. We present simulations that lead to scaling laws for the velocity and acceleration of the front as a function of the system size and the level of noise, and analytic arguments that explain these results in terms of the noisy pole dynamics.This version corrects some very critical errors made in arXiv:adap-org/9608001 and makes more detailed description of excess number of poles in system, number of poles that appear in the system in unit of time, life time of pole. It allows us to understand more correctly dependence of the system parameters on noise than in arXiv:adap-org/9608001Comment: 23 pages, 4 figures,revised, version accepted for publication in journal "Combustion, Explosion and Shock Waves". arXiv admin note: substantial text overlap with arXiv:nlin/0302021, arXiv:adap-org/9608001, arXiv:nlin/030201

Obesity – threat to the reproductive potential of Russia

Obesity is a recurring polyetiological disease. Overweight are 30–60% of women of reproductive age, and 25–27% are obese. By 2025, it is expected that 50% of women on our planet will be obese. Obesity in women of reproductive age is accompanied by a high frequency of anovulation, hyperandrogenism, menstrual irregularities, endometrial pathology, infertility. During pregnancy, this group of women has a higher risk of short term loss, including pregnancy in the outcome of assisted reproductive technologies. Weight gain and obesity can lead to decreased fertility in women. The body mass index of a woman of reproductive age negatively affects the course of pregnancy, namely: the risk of gestational diabetes, increased blood pressure, eclampsia, the pathological course of the birth act and the pathology of the newborn increase. Obesity in women of reproductive age is an independent risk factor for cancer: breast cancer and endometrial cancer, and also leads to a decrease in the survival rate for ovarian cancer. Obesity often accompanies polycystic ovary syndrome, which occurs in every 10th patient of reproductive age. The combination of these diseases increases the risk of cardiometabolic conditions such as impaired glucose tolerance, type 2 diabetes and dyslipidemia. Weight loss in these patients is a necessary component of complex therapy aimed at improving reproductive potential

Behavioral phenotyping of mice deficient for tumor necrosis factor

The tumor necrosis factor (TNF) is a cytokine exerting both homeostatic and pathophysiological roles in the central nervous system (CNS). It has been demonstrated that TNF plays roles in such diseases as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis. Nevertheless, the role of TNF in the CNS under normal physiological conditions is poorly studied. A novel mouse strain with TNF deficiency (TNFKO) was developed in S.A. Nedospa­sov’s labora­tory of Engelhardt Institute of Molecular Bio­logy of the Russian Academy of Sciences on the C57Bl/6 (WT) background. In our study, we compared the behavior of TNFKO and WT adult mice in a battery of tests: open-field, elevated plus-maze and the forced-swim test. We showed that TNF deficiency had no effect on locomotor activity or exploration in the openfield test. At the same time, in this test, TNFKO mice spent more time in the center of the arena, but had a higher level of defecation and lower rearing duration. This result indicates that, in the openfield conditions, TNFKO mice show disorientation rather than anxiety-like behavior. There were no differences between TNFKO and WT in anxiety level in the elevated plus-maze test or in depressive-like behavior in the forcedswim test. These data suggest that TNF deficiency leads to changes in neurofunctional interactions that alter the mouse response to mild stress in the open-field test

Obesity and reproductive function of women: epigenetic and somato-psychological features

The review article presents data on the effects of obesity on the female reproductive system and offspring of mothers with overweight or obesity, such as infertility, miscarriages, premature birth, stillbirth, congenital anomalies and prematurity, as well as a high risk of cesarean section. Obesity accompanies polycystic ovary syndrome, worsening the metabolic profile and increasing the risk of developing depression and eating disorders. Maternal obesity and hyperglycemia are able to influence the formation of the fetus by epigenetic mechanisms without affecting the nucleotide sequences. Subsequently, the metabolic and cardiovascular risks increase in the descendants of obese or overweight mothers and gestational diabetes. Patients with obesity are characterized by a folic acid deficiency and a deficiency of the luteal phase. Exogenous administration of these substances improves pregnancy outcomes and prevents congenital malformations

Conducting and automating the water Morris maze test in SPF conditions

The water Morris maze is the basic test to study the spatial ability to learn as well as spatial memory in laboratory rodents. It is a part of a series of tests necessary for behavioral phenotyping of mutant and transgenic mice. At the same time, conducting this test in SPF conditions must comply with very strict regulations concerning pathogen control. A white animal on the surface of whitened water is low contrast and this does not allow the animal to be traced automatically, which represents yet another major problem. A unique installation based on EthoStudio has been developed at the Institute of Cytology and Genetics SB RAS and the Institute of Automation and Electrometry SB RAS. This installation automates the process of tracing mice of any coat color in SPF conditions. This includes a setup to install a plastic water reservoir (110×40 cm), a digital camera and a light source. Water to fill the reservoir was sterilized using a Van Erp Blue Lagoon UV-C Tech 15000 ultraviolet decontaminator. The image of an animal was processed in a frame-by-frame fashion using the EthoStudio program, with the following parameters calculated: latent release time, route covered, cumulative distance to the platform and the time spent in the reservoir sectors. With this installation, we were able to study the spatial ability to learn and spatial memory in mice of the C57BL/6 strain and in mice of the C57BL/6/ Kaiso strain developed on the C57BL/6 background, with the gene encoding the methyl-DNA binding Kaiso protein knocked-out. It has been demonstrated that mice of these strains are able to learn to find the platform in the water Morris maze and have the location of the platform in their memory for at least the next four days

Effect of lethal yellow (AY) mutation and photoperiod alterations on mouse behavior

Decrease in natural illumination in fall/winter months causes depressive-like seasonal affective disorders in vulnerable individuals. Obesity is another risk factor of depression. The lethal yellow (AY) mutation causes ectopic expression of agouti protein in the brain. Mice heterozygous for AY mutation (AY/a) are obese compared to their wild-type littermates (a/a). The main aims of the study were to investigate the effects of AY mutation, photoperiod and the interaction between these factors on daily activity dynamics, feeding, locomotor and exploratory activities, anxiety-related and depressive-like behaviors in mild stress condition. Six weeks old mouse males of AY/a and a/a lines were divided into four groups eight animals each and exposed to long- (14 h light and 10 h darkness) or short- (4 h light and 20 h darkness) day conditions for 28 days. Then the behavior of these mice was successively investigated in the home cage, open field, elevated plus-maze and forced swim tests. We did not observed any effect of AY mutation on the general activity, water and food consumption in the home cage; locomotion and exploration in the open field test; anxiety-related behavior in the open field and elevated plus-maze tests. At the same time, AY mutation increased depressive-like immobility time in the forced swim test (F1.28 = 20.03, p = 0.00012). Shortday conditions decreased nocturnal activity in the home cage, as well as locomotion (F1.28 = 16.33, p = 0.0004) and exploration (F1.28 = 16.24, p < 0.0004) in the open field test. Moreover, short-day exposition decreased time spent in the center of the open field (F1.28 = 6.57, p = 0.016) and in the open arms of the elevated plus-maze (F1.28 = 12.08, p = 0.0017) tests and increased immobility time in the forced swim test (F1.28 = 9.95, p = 0.0038). However, no effect of the interaction between AY mutation and photoperiod on immobility time in the forced swim test was observed. Therefore, short-day photoperiod and AY mutation increased depressive-like behavior in the forced swim test by means of different mechanisms

Submillimeter ESR spectra of Fe²⁺ ions in synthetic and natural beryl crystals

© 2017, Pleiades Publishing, Ltd. Electron spin resonance spectra of non-Kramers bivalent iron (Fe 2+ ) ions have been detected in synthetic and natural beryl crystals with an iron impurity. The observed ESR spectra have been attributed to resonance transitions of Fe 2+ ions from the ground (singlet) state to excited (doublet) levels with the splitting Δ = 12.7 cm –1 between the levels. The experimental angular and frequency dependences of the resonance field of the ESR signal have been described by the spin Hamiltonian with the effective spin S = 1. The analysis of the ESR data and optical absorption spectra indicates that the Fe 2+ ions are situated in tetrahedral positions and substitute Be 2+ cations in the beryl structure

The United States Congress and nuclear war powers: explaining legislative nonfeasance

Scholarly debate over the role of the United States Congress in approving military action has focused on the respective war powers granted the executive and legislature by the United States Constitution. Although a voluminous literature has examined the institutional and partisan politics shaping their exercise, a conspicuous lacuna concerns nuclear war powers. Despite periodic but mostly ineffective reassertions of congressional prerogatives over war, the decision to employ nuclear weapons has been left entirely to presidential discretion since 1945. Explaining this consistent refusal by Congress to rein in the ultimate presidential power and exercise co-responsibility for the most devastating form of war relies less on disputatious constitutional grounds than on three arguments about congressional dysfunctionality, legislative irresponsibility, and the relative costs of collective action by federal lawmakers on perilous national security questions