Tube Models for Rubber-Elastic Systems

In the first part of the paper we show that the constraining potentials introduced to mimic entanglement effects in Edwards' tube model and Flory's constrained junction model are diagonal in the generalized Rouse modes of the corresponding phantom network. As a consequence, both models can formally be solved exactly for arbitrary connectivity using the recently introduced constrained mode model. In the second part, we solve a double tube model for the confinement of long paths in polymer networks which is partially due to crosslinking and partially due to entanglements. Our model describes a non-trivial crossover between the Warner-Edwards and the Heinrich-Straube tube models. We present results for the macroscopic elastic properties as well as for the microscopic deformations including structure factors.Comment: 15 pages, 8 figures, Macromolecules in pres

Does Self-Compassion Protect Adolescents from Stress?

The aim of this study was to determine whether adolescents who were high in self-compassion self-reported different levels of emotional wellbeing than adolescents who were low in self-compassion, and to determine whether those high in self-compassion responded differently under a lab social stressor than those low in self-compassion. In a lab setting, participants (age 13–18; n = 28) completed the Trier Social Stress Test (TSST) and physiological stress was assessed via salivary cortisol, heart rate, blood pressure, and heart rate variability at baseline, during the TSST, and during recovery. After completing the lab protocol, an email was sent to participants that provided a link to an online survey which was composed of emotional wellbeing measures including perceived stress, life satisfaction, positive and negative affect. After conducting repeated measure ANOVAS to determine that the TSST induced a significant stress response, the sample was split at the median of self-compassion. T tests were conducted to determine meaningful differences (Hedges’ g > .20) between the groups. Findings indicated that those in the high self-compassion group (≥the median) self-reported greater emotional wellbeing than those in the low self-compassion group (<the median). Overall, those in the high self-compassion group also had a lower physiologic stress response when exposed to the TSST than those in the low self-compassion group. Regression analyses were also conducted; baseline self-compassion predicted self-reported emotional wellbeing, but did not predict physiological response to the TSST. Findings support the potential buffering effect that self-compassion may have in protecting adolescents from social stressors; yet more research needs to be conducted in larger samples to confirm and replicate these findings

Annual variation in the levels of transcripts of sex-specific genes in the mantle of the common mussel, Mytilus edulis

Mytilus species are used as sentinels for the assessment of environmental health but sex or stage in the reproduction cycle is rarely considered even though both parameters are likely to influence responses to pollution. We have validated the use of a qPCR assay for sex identification and related the levels of transcripts to the reproductive cycle. A temporal study of mantle of Mytilus edulis found transcripts of male-specific vitelline coat lysin (VCL) and female-specific vitelline envelope receptor for lysin (VERL) could identify sex over a complete year. The levels of VCL/VERL were proportional to the numbers of sperm/ova and are indicative of the stage of the reproductive cycle. Maximal levels of VCL and VERL were found in February 2009 declining to minima between July - August before increasing and re-attaining a peak in February 2010. Water temperature may influence these transitions since they coincide with minimal water temperature in February and maximal temperature in August. An identical pattern of variation was found for a cryptic female-specific transcript (H5) but a very different pattern was observed for oestrogen receptor 2 (ER2). ER2 varied in a sex-specific way with male > female for most of the cycle, with a female maxima in July and a male maxima in December. Using artificially spawned animals, the transcripts for VCL, VERL and H5 were shown to be present in gametes and thus their disappearance from mantle is indicative of spawning. VCL and VERL are present at equivalent levels in February and July-August but during gametogenesis (August to January) and spawning (March to June) VCL is present at lower relative amounts than VERL. This may indicate sex-specific control mechanisms for these processes and highlight a potential pressure point leading to reduced reproductive output if environmental factors cause asynchrony to gamete maturation or release

Goos-H\"{a}nchen-like shifts for Dirac fermions in monolayer graphene barrier

We investigate the Goos-H\"{a}nchen-like shifts for Dirac fermions in transmission through a monolayer graphene barrier. The lateral shifts, as the functions of the barrier's width and the incidence angle, can be negative and positive in Klein tunneling and classical motion, respectively. Due to their relations to the transmission gap, the lateral shifts can be enhanced by the transmission resonances when the incidence angle is less than the critical angle for total reflection, while their magnitudes become only the order of Fermi wavelength when the incidence angle is larger than the critical angle. These tunable beam shifts can also be modulated by the height of potential barrier and the induced gap, which gives rise to the applications in graphene-based devices.Comment: 5 pages, 5 figure

A Pilot Study with a Novel Setup for Collaborative Play of the Humanoid Robot KASPAR with children with autism

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article describes a pilot study in which a novel experimental setup, involving an autonomous humanoid robot, KASPAR, participating in a collaborative, dyadic video game, was implemented and tested with children with autism, all of whom had impairments in playing socially and communicating with others. The children alternated between playing the collaborative video game with a neurotypical adult and playing the same game with the humanoid robot, being exposed to each condition twice. The equipment and experimental setup were designed to observe whether the children would engage in more collaborative behaviours while playing the video game and interacting with the adult than performing the same activities with the humanoid robot. The article describes the development of the experimental setup and its first evaluation in a small-scale exploratory pilot study. The purpose of the study was to gain experience with the operational limits of the robot as well as the dyadic video game, to determine what changes should be made to the systems, and to gain experience with analyzing the data from this study in order to conduct a more extensive evaluation in the future. Based on our observations of the childrens’ experiences in playing the cooperative game, we determined that while the children enjoyed both playing the game and interacting with the robot, the game should be made simpler to play as well as more explicitly collaborative in its mechanics. Also, the robot should be more explicit in its speech as well as more structured in its interactions. Results show that the children found the activity to be more entertaining, appeared more engaged in playing, and displayed better collaborative behaviours with their partners (For the purposes of this article, ‘partner’ refers to the human/robotic agent which interacts with the children with autism. We are not using the term’s other meanings that refer to specific relationships or emotional involvement between two individuals.) in the second sessions of playing with human adults than during their first sessions. One way of explaining these findings is that the children’s intermediary play session with the humanoid robot impacted their subsequent play session with the human adult. However, another longer and more thorough study would have to be conducted in order to better re-interpret these findings. Furthermore, although the children with autism were more interested in and entertained by the robotic partner, the children showed more examples of collaborative play and cooperation while playing with the human adult.Peer reviewe

Enhancing stress reactivity and wellbeing in early schizophrenia: A pilot study of individual coping awareness therapy (I-CAT)

Dear Editors: Positive psychology strategies and mindfulness are two non-traditional approaches to psychotherapy increasingly employed to aid recovery from psychosis (Shonin et al. 2014; Slade 2010). Positive psy-chology interventions focus on increasing experiences of positive emo-tions to improve wellbeing (Rashid 2015), while mindfulness interventions reduce stress reactivity, and facilitate experiences of pos-itive emotions (Geschwind et al. 2011; Gu et al., 2015)

Disease Detection by Ultrasensitive Quantification of Microdosed Synthetic Urinary Biomarkers

The delivery of exogenous agents can enable noninvasive disease monitoring, but existing low-dose approaches require complex infrastructure. In this paper, we describe a microdose-scale injectable formulation of nanoparticles that interrogate the activity of thrombin, a key regulator of clotting, and produce urinary reporters of disease state. We establish a customized single molecule detection assay that enables urinary discrimination of thromboembolic disease in mice using doses of the nanoparticulate diagnostic agents that fall under regulatory guidelines for “microdosing.”National Science Foundation (U.S.). Graduate Research FellowshipNational Institutes of Health (U.S.) (Ruth L. Kirschstein National Research Service Award F32CA159496-02)Burroughs Wellcome Fund (Career Award at the Scientific Interface)National Cancer Institute (U.S.) (Koch Institute Support (Core) Grant P30-CA14051)David H. Koch Institute for Integrative Cancer Research at MIT (Frontier Research Program

Ocean acidification through the lens of ecological theory

Ocean acidification, chemical changes to the carbonate system of seawater, is emerging as a key environmental challenge accompanying global warming and other human-induced perturbations. Considerable research seeks to define the scope and character of potential outcomes from this phenomenon, but a crucial impediment persists. Ecological theory, despite its power and utility, has been only peripherally applied to the problem. Here we sketch in broad strokes several areas where fundamental principles of ecology have the capacity to generate insight into ocean acidification's consequences. We focus on conceptual models that, when considered in the context of acidification, yield explicit predictions regarding a spectrum of population- and community-level effects, from narrowing of species ranges and shifts in patterns of demographic connectivity, to modified consumer–resource relationships, to ascendance of weedy taxa and loss of species diversity. Although our coverage represents only a small fraction of the breadth of possible insights achievable from the application of theory, our hope is that this initial foray will spur expanded efforts to blend experiments with theoretical approaches. The result promises to be a deeper and more nuanced understanding of ocean acidification and the ecological changes it portends

Reconstruction of cellular variability from spatiotemporal patterns of Dictyostelium discoideum

Variability in cell properties can be an important driving mechanism behind spatiotemporal patterns in biological systems, as the degree of cell-to-cell differences determines the capacity of cells to locally synchronize and, consequently, form patterns on a larger spatial scale. In principle, certain features of spatial patterns emerging with time may be regulated by variability or, more specifically, by certain constellations of cell-to-cell differences. Similarly, measuring variability in a system (i.e. the spatial distribution of cell-cell differences) may help predict properties of later-stage patterns

Inorganic carbon physiology underpins macroalgal responses to elevated CO2

Beneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3- use (\u3b413C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3- and CO2 had greater CO2 use as concentrations increased. These species (and one unable to use HCO3-) increased in abundance with elevated CO2 whereas obligate calcifying species, and non-calcareous macroalgae whose CO2 use did not increase consistently with concentration, declined in abundance. Physiological groupings provide a mechanistic understanding that will aid us in determining which species will benefit from ocean acidification and why