Technology in gastroenterology

No Abstract

Ordered and disordered dynamics in monolayers of rolling particles

We consider the ordered and disordered dynamics for monolayers of rolling self-interacting particles with an offset center of mass and a non-isotropic inertia tensor. The rolling constraint is considered as a simplified model of a very strong, but rapidly decaying bond with the surface, preventing application of the standard tools of statistical mechanics. We show the existence and nonlinear stability of ordered lattice states, as well as disturbance propagation through and chaotic vibrations of these states. We also investigate the dynamics of disordered gas states and show that there is a surprising and robust linear connection between distributions of angular and linear velocity for both lattice and gas states, allowing to define the concept of temperature

Self-Compassion, Social Connectedness, and Interpersonal Competence

Self-compassion has consistently been found to be related to well-being (Barnard & Curry 2011). Most research has focused on the intrapersonal benefits of self-compassion, such as its positive relationships with happiness, optimism, positive affect (Neff & Vonk, 2009), and life satisfaction (Neff, Kirkpatrick, & Rude, 2007). In contrast, little research has addressed how engaging in self-compassion may be beneficial to one’s relationships. There is strong evidence that social connectedness (e.g. Lee, Draper, & Lee, 2001; Lee & Robbins, 1998; Mauss et al., 2011; Neff, 2003b) and interpersonal competence (e.g Fiori, Antonucci, & Cortina, 2006; Berkman & Syme, 1979; Delongis, Folkman, & Lazarus, 1988) are positively related to well-being in a variety of ways. The purpose of this study was to investigate whether self-compassion is related to social connectedness and interpersonal competence. Responding to oneself with self-compassion may allow a person to be more present and attentive to others in interpersonal contexts, rather than being self-critical and focused on one’s own manner of engaging. Two hundred thirty-one participants were recruited from a university in the pacific northwest and completed the Self-Compassion Scale (SCS; Neff, 2003b), Social Connectedness Scale-Revised (SCS-R; Lee, Draper, & Lee, 2001), and Interpersonal Competence Questionnaire (ICQ; Buhrmester, Furman, Wittenberg, & Reis, 1988). Self-compassion was examined as a global construct. In addition, six components of self-compassion were also explored: “(a) self-kindness­­—extending kindness and understanding to oneself, (b) common humanity—seeing one’s experiences as part of the larger human experience, and (c) mindfulness—holding one’s painful thoughts and feelings in balanced awareness,” as well as the opposites of these, (self-judgment versus self-kindness, isolation versus common humanity, and over-identification versus mindfulness; Neff, 2003b). Results indicated that: 1) self-compassion and all of its subscales are significantly related to social connectedness, 2) the self-kindness and isolation subscales of self-compassion are predictive of social connectedness, 3) people reporting a greater tendency toward self-compassion were more likely to report initiating interpersonal interactions with others, engaging in more self-disclosure, and offering more emotional support to others, and 4) the components of self-compassion are all significantly related to the initiation and self-disclosure domains of interpersonal competence, but they have a more complex relationship with emotional support. These results lend further support to the importance of self-compassion to interpersonal functioning and underscore its importance to well-being overall

Sub-Doppler resonances in the back-scattered light from random porous media infused with Rb vapor

We report on the observation of sub-Doppler resonances on the back-scattered light from a random porous glass medium with rubidium vapor filling its interstices. The sub-Doppler spectral lines are the consequence of saturated absorption where the incident laser beam saturates the atomic medium and the back-scattered light probes it. Some specificities of the observed spectra reflect the transient atomic evolution under confinement inside the pores. Simplicity, robustness and potential miniaturization are appealing features of this system as a spectroscopic reference.Comment: 6 pages, 4 figure

Discrimination of the Healthy and Sick Cardiac Autonomic Nervous System by a New Wavelet Analysis of Heartbeat Intervals

We demonstrate that it is possible to distinguish with a complete certainty between healthy subjects and patients with various dysfunctions of the cardiac nervous system by way of multiresolutional wavelet transform of RR intervals. We repeated the study of Thurner et al on different ensemble of subjects. We show that reconstructed series using a filter which discards wavelet coefficients related with higher scales enables one to classify individuals for which the method otherwise is inconclusive. We suggest a delimiting diagnostic value of the standard deviation of the filtered, reconstructed RR interval time series in the range of $\sim 0.035$ (for the above mentioned filter), below which individuals are at risk.Comment: 5 latex pages (including 6 figures). Accepted in Fractal

A variational problem on Stiefel manifolds

In their paper on discrete analogues of some classical systems such as the rigid body and the geodesic flow on an ellipsoid, Moser and Veselov introduced their analysis in the general context of flows on Stiefel manifolds. We consider here a general class of continuous time, quadratic cost, optimal control problems on Stiefel manifolds, which in the extreme dimensions again yield these classical physical geodesic flows. We have already shown that this optimal control setting gives a new symmetric representation of the rigid body flow and in this paper we extend this representation to the geodesic flow on the ellipsoid and the more general Stiefel manifold case. The metric we choose on the Stiefel manifolds is the same as that used in the symmetric representation of the rigid body flow and that used by Moser and Veselov. In the extreme cases of the ellipsoid and the rigid body, the geodesic flows are known to be integrable. We obtain the extremal flows using both variational and optimal control approaches and elucidate the structure of the flows on general Stiefel manifolds.Comment: 30 page

A new Bloch period for interacting cold atoms in 1D optical lattices

The paper studies Bloch oscillations of ultracold atoms in optical lattice in the presence of atom-atom interaction. A new, interaction-induced Bloch period is identified. The analytical results are corroborated by realistic numerical calculations.Comment: revtex4, 4 pages, 4 figures, gzipped tar fil