Harmonic oscillators in the Nos\'e - Hoover thermostat

We study the dynamics of an ensemble of non-interacting harmonic oscillators in a nonlinear dissipative environment described by the Nos\'e - Hoover model. Using numerical simulation we find the histogram for total energy, which agrees with the analysis of the Nos\'e - Hoover equations effected with the method of averaging. The histogram does not correspond to Gibbs' canonical distribution. We have found oscillations at frequency proportional to $\sqrt{\alpha/m}$, $\alpha$ the dissipative parameter of thermostat and $m$ the characteristic mass of particle, about the stationary state corresponding to equilibrium. The oscillations could have an important bearing upon the analysis of simulating molecular dynamics in the Nos\'e - Hoover thermostat.Comment: 7 pages, 4 figure

Title Stabilization of Membrane Pores by Packing

We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks tending to re-seal or grows without bound til to membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a multipore membrane system, the distribution of pore size and associated pore lifetime are calculated within the mean field approximation. We predict that, above certain temperature when the effective line tension becomes negative, the membrane exhibits a dynamic sieve-like porous structure.Comment: 4 pages, 4 figure

Bond graphs in model matching control

Bond graphs are primarily used in the network modeling of lumped parameter physical systems, but controller design with this graphical technique is relatively unexplored. It is shown that bond graphs can be used as a tool for certain model matching control designs. Some basic facts on the nonlinear model matching problem are recalled. The model matching problem is then associated with a particular disturbance decoupling problem, and it is demonstrated that bicausal assignment methods for bond graphs can be applied to solve the disturbance decoupling problem as to meet the model matching objective. The adopted bond graph approach is presented through a detailed example, which shows that the obtained controller induces port-Hamiltonian error dynamics. As a result, the closed loop system has an associated standard bond graph representation, thereby rendering energy shaping and damping injection possible from within a graphical context

Symmetry breaking in low-dimensional SU(N) antiferromagnets

Consequences of explicit symmetry breaking in a physically motivated model of SU(N) antiferromagnet in spatial dimensions one and two are studied. It is shown that the case N=3, which can be realized in spin-1 cold atom systems, displays special properties distinctly different from those for N>=4. Qualitative form of the phase diagram depending on the model parameters is given.Comment: 10 pages, 2 figures; added references, corrected fig.2; the final version to appear in PR

Symmetries of Electrostatic Interaction between DNA Molecules

We study a model for pair interaction $U$ of DNA molecules generated by the discrete dipole moments of base-pairs and the charges of phosphate groups, and find noncommutative group of eighth order ${\cal S}$ of symmetries that leave $U$ invariant. We classify the minima using group ${\cal S}$ and employ numerical methods for finding them. The minima may correspond to several cholesteric phases, as well as phases formed by cross-like conformations of molecules at an angle close to $\rm{90}^{o}$, "snowflake phase". The results depend on the effective charge $Q$ of the phosphate group which can be modified by the polycations or the ions of metals. The snowflake phase could exist for $Q$ above the threshold $Q_C$. Below $Q_C$ there could be several cholesteric phases. Close to $Q_C$ the snowflake phase could change into the cholesteric one at constant distance between adjacent molecules.Comment: 13 pages, 4 figure

Childhood trauma, posttraumatic stress disorder symptoms, early maladaptive schemas, and schema modes : a comparison of individuals with obesity and normal weight controls

Background: Previous research on the psychological mechanisms of obesity has primarily focused on acute psychopathology. However, there is limited literature on the role of more complex and entrenched psychological processes in weight management. The current study aimed to expand previous research by examining more enduring psychological constructs, including early maladaptive schemas (EMS), schemas modes, and trauma. Methods: Participants (N=125) comprised adults with normal weight (n=40) and obesity (n=85) from community and clinical settings in Australia. Eligible participants completed a series of self-report questionnaires via Research Electronic Data Capture (REDCap). Two, separate, one-way multivariate analysis of variance (MANOVA) were conducted to examine group differences on the outcome variables. Results: Findings indicated a significant effect of group on EMS and schema modes, V=.51, F(32, 92)=2.97, p<.001, partial η2=.51. Follow-up univariate tests revealed that individuals with obesity endorsed significantly more maladaptive schemas and schema modes and significantly less healthy schema modes than individuals with normal weight. In addition, results demonstrated a significant effect of group on childhood trauma and posttraumatic stress disorder (PTSD) symptoms, V=.19, F(6, 118)=4.70, p<.001, partial η2=.19. Subsequent univariate tests and chi-square analyses indicated that individuals with obesity reported significantly more childhood trauma as well as significantly more PTSD symptoms within the last month than normal weight individuals. Conclusion: This was the first study to compare EMS and schema modes in treatment-seeking individuals with obesity and normal weight controls using the short form version 3 of the Young Schema Questionnaire and revised, 118-item, Schema Mode Inventory. Overall, findings revealed that individuals with obesity experience more complex and enduring psychological difficulties than normal weight individuals. Increased assessment and targeted treatment of these underlying mental health concerns may contribute to a more holistic conceptualisation of obesity and could improve the long-term success of weight management

Efficacy of telephone health coaching integration with standard multidisciplinary care for adults with obesity attending a weight management service : a pilot study

Australia has one of the highest prevalences of obesity in the developed world with recognised gaps in patient access to obesity services. This non-randomised before and after study investigated the health benefits and patient acceptability of integrating the Get Healthy Service, a state-funded telephone-delivered coaching service in Australia, as an adjunct to multidisciplinary care for adults attending a public obesity service. Forty-one participants received multidisciplinary care alone while 39 participants were subsequently allocated to receive adjunctive treatment with the Get Healthy Service. Weight, body mass index, glycosylated haemoglobin, measurement of hepatic steatosis and liver enzymes were collected at baseline and 6 months. Participant evaluation was obtained post intervention. Statistically significant reductions from baseline were achieved for both control and intervention with respect to weight (−6.7 ± 2.2 kg, p = 0.01; −12.6 ± 3.2, p = 0.002), body mass index (−2.3 ± 0.8, p = 0.01; −4.8 ± 1.2 kg/m2 , p = 0.002) and glycosylated haemoglobin (−0.2 ± 0.2%, p = 0.2 (NS); −0.7 ± 0.2%, p = 0.02), respectively. There were no significant differences in steatosis or liver enzymes or in outcomes between control and intervention cohorts. A high level of patient acceptability was reported. Integrating telephone-delivered coaching provided non-inferior care and high levels of patient satisfaction. Telephone coaching aligned with the principles of an obesity service should be trialled to improve patient access to obesity interventions

Acoustic Spectroscopy of the DNA in GHz range

We find a parametric resonance in the GHz range of the DNA dynamics, generated by pumping hypersound . There are localized phonon modes caused by the random structure of elastic modulii due to the sequence of base pairs

The role of gut-derived microbial antigens on liver fibrosis initiation and progression

Intestinal dysbiosis has recently become known as an important driver of gastrointestinal and liver disease. It remains poorly understood, however, how gastrointestinal microbes bypass the intestinal mucosa and enter systemic circulation to enact an inflammatory immune response. In the context of chronic liver disease (CLD), insults that drive hepatic inflammation and fibrogenesis (alcohol, fat) can drastically increase intestinal permeability, hence flooding the liver with gut-derived microbiota. Consequently, this may result in exacerbated liver inflammation and fibrosis through activation of liver-resident Kupffer and stellate cells by bacterial, viral, and fungal antigens transported to the liver via the portal vein. This review summarizes the current understanding of microbial translocation in CLD, the cell-specific hepatic response to intestinal antigens, and how this drives the development and progression of hepatic inflammation and fibrosis. Further, we reviewed current and future therapies targeting intestinal permeability and the associated, potentially harmful anti-microbial immune response with respect to their potential in terms of limiting the development and progression of liver fibrosis and end-stage cirrhosis

Gauge symmetry enhancement in Hamiltonian formalism

We study the Hamiltonian structure of the gauge symmetry enhancement in the enlarged CP(N) model coupled with U(2) Chern-Simons term, which contains a free parameter governing explicit symmetry breaking and symmetry enhancement. After giving a general discussion of the geometry of constrained phase space suitable for the symmetry enhancement, we explicitly perform the Dirac analysis of our model and compute the Dirac brackets for the symmetry enhanced and broken cases. We also discuss some related issues.Comment: 8 pages, typos correcte