A periodic elastic medium in which periodicity is relevant

We analyze, in both (1+1)- and (2+1)- dimensions, a periodic elastic medium in which the periodicity is such that at long distances the behavior is always in the random-substrate universality class. This contrasts with the models with an additive periodic potential in which, according to the field theoretic analysis of Bouchaud and Georges and more recently of Emig and Nattermann, the random manifold class dominates at long distances in (1+1)- and (2+1)-dimensions. The models we use are random-bond Ising interfaces in hypercubic lattices. The exchange constants are random in a slab of size $L^{d-1} \times \lambda$ and these coupling constants are periodically repeated along either {10} or {11} (in (1+1)-dimensions) and {100} or {111} (in (2+1)-dimensions). Exact ground-state calculations confirm scaling arguments which predict that the surface roughness $w$ behaves as: $w \sim L^{2/3}, L \ll L_c$ and $w \sim L^{1/2}, L \gg L_c$, with $L_c \sim \lambda^{3/2}$ in $(1+1)$-dimensions and; $w \sim L^{0.42}, L \ll L_c$ and $w \sim \ln(L), L \gg L_c$, with $L_c \sim \lambda^{2.38}$ in $(2+1)$-dimensions.Comment: Submitted to Phys. Rev.

On the thermodynamics of first-order phase transition smeared by frozen disorder

The simplified model of first-order transition in a media with frozen long-range transition-temperature disorder is considered. It exhibits the smearing of the transition due to appearance of the intermediate inhomogeneous phase with thermodynamics described by the ground state of the short-range random-field Ising model. Thus the model correctly reproduce the persistence of first-order transition only in dimensions d > 2, which is found in more realistic models. It also allows to estimate the behavior of thermodynamic parameters near the boundaries of the inhomogeneous phase.Comment: 4 page

Aeolian sans ripples: experimental study of saturated states

We report an experimental investigation of aeolian sand ripples, performed both in a wind tunnel and on stoss slopes of dunes. Starting from a flat bed, we can identify three regimes: appearance of an initial wavelength, coarsening of the pattern and finally saturation of the ripples. We show that both initial and final wavelengths, as well as the propagative speed of the ripples, are linear functions of the wind velocity. Investigating the evolution of an initially corrugated bed, we exhibit non-linear stable solutions for a finite range of wavelengths, which demonstrates the existence of a saturation in amplitude. These results contradict most of the models.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Lett. Title changed, figures corrected and simplified, more field data included, text clarifie

The neural correlates of social connection

Cultivating social connection has long been a goal of psychology, philosophy, religion, and public policy. Yet the psychological and neural responses that accompany a feeling of connection to others remain unclear. In the present study, we used functional neuroimaging to shed light on the neural correlates of self- and other-focused processes during the successful self-generation of feelings of social connection. To do this, we used a trait judgment task to localize functional activation related to self-focused thought. We then examined brain responses during guided exercises designed both to encourage feeling love and connection from others (i.e., self-focused) and to generate feelings of love and connection toward others (i.e., other-focused). Our results indicated that generating feelings of social connection recruited a portion of the medial prefrontal cortex (MPFC) implicated in thinking about both the self and others. Within this larger area, we observed distinct profiles of activation within different subregions. Although rostral anterior cingulate cortex was more strongly activated by other-focused components of the task, a more dorsal portion of MPFC was comparatively more active during primarily self-focused components of the task. Somewhat surprisingly, stronger feelings of social connection were not associated with greater activation in the anterior cingulate, but rather with less activation in the dorsal region of the MPFC related to self-focused thought. These results are consistent with the possibility that reducing certain kinds of self-focused thought might yield a greater sense of social connection to and care for others

Response to antipsychotic drugs in treatment-resistant schizophrenia : Conclusions based on systematic review

Peer reviewe

Magnetic nanocomposites at microwave frequencies

Most conventional magnetic materials used in the electronic devices are ferrites, which are composed of micrometer-size grains. But ferrites have small saturation magnetization, therefore the performance at GHz frequencies is rather poor. That is why functionalized nanocomposites comprising magnetic nanoparticles (e.g. Fe, Co) with dimensions ranging from a few nm to 100 nm, and embedded in dielectric matrices (e.g. silicon oxide, aluminium oxide) have a significant potential for the electronics industry. When the size of the nanoparticles is smaller than the critical size for multidomain formation, these nanocomposites can be regarded as an ensemble of particles in single-domain states and the losses (due for example to eddy currents) are expected to be relatively small. Here we review the theory of magnetism in such materials, and we present a novel measurement method used for the characterization of the electromagnetic properties of composites with nanomagnetic insertions. We also present a few experimental results obtained on composites consisting of iron nanoparticles in a dielectric matrix.Comment: 20 pages, 10 figures, 5 table

The prognostic value of extramural venous invasion in preoperative MRI of rectal cancer patients

Aim This study aimed to examine the prognostic value of extramural venous invasion observed in preoperative MRI on survival and recurrences. Method In total, 778 rectal cancer patients were evaluated in multidisciplinary meetings in Helsinki University Hospital during the years 2016-2018. 635 patients met the inclusion criteria of stage I-III disease and were intended for curative treatment at the time of diagnosis. 128 had extramural venous invasion in preoperative MRI. Results The median follow-up time was 2.5 years. In a univariate analysis extramural venous invasion was associated with poorer disease-specific survival (hazard ratio [HR] 2.174, 95% CI 1.118-4.224, P = 0.022), whereas circumferential margin = T3c or nodal positivity were not. Disease recurrence occurred in 17.3% of the patients: 13.4% had metastatic recurrence only, 1.7% mere local recurrence and 2.2% both metastatic and local recurrence. In multivariate analysis, extramural venous invasion (HR 1.734, 95% CI 1.127-2.667, P = 0.012) and nodal positivity (HR 1.627, 95% CI 1.071-2.472, P = 0.023) were risk factors for poorer disease-free survival (DFS). Circumferential marginPeer reviewe

Loving-kindness meditation: a tool to improve healthcare provider compassion, resilience, and patient care

Background: Stress is a critical problem facing many healthcare institutions. The consequences of stress include increased provider burnout and decreased quality of care for patients. Ironically, a key factor that may help buffer the impact of stress on provider well-being and patient health outcomes—compassion—is low in healthcare settings and declines under stress. This gives rise to an urgent question: what practical steps can be taken to increase compassion, thereby benefitting both provider well-being and patient care? Methods: We investigated the relative effectiveness of a short, 10-minute session of loving-kindness meditation (LKM) to increase compassion and positive affect. We compared LKM to a non-compassion positive affect induction (PAI) and a neutral visualization (NEU) condition. Self- and other-focused affect, self-reported measures of social connection, and semi-implicit measures of self-focus were measured pre- and post- meditation using repeated measures ANOVAs and via paired sample t-tests for follow-up comparisons. Results: Findings show that LKM improves well-being and feelings of connection over and above other positive-affect inductions, at both explicit and implicit levels, while decreasing self-focus in under 10 minutes and in novice meditators. Conclusions: These findings suggest that LKM may be a viable, practical, and time-effective solution for preventing burnout and promoting resilience in healthcare providers and for improving quality of care in patients