7,649 research outputs found
"Third places" and social interaction in deprived neighbourhoods in Great Britain
This paper explores social interaction in local âpublicâ social spaces such as local shops, pubs, cafĂ©s, and community centres in deprived neighbourhoods. More specifically, it examines the importance, role and function of these places, which have been described by Oldenberg and Brissett (Qual Sociol 5(4):265â284, 1982), Oldenburg (Urban design reader. Architectural Place, Oxford, 2007) as being âthird placesâ of social interaction after the home (first) and workplace (second). It does so by drawing on data gleaned from in-depth interviews with 180 residents in six deprived areas neighbourhoods across Great Britain, conducted as part of a study of the links between poverty and place funded by the Joseph Rowntree Foundation. The paper notes that local third places are an important medium for social interaction in these areas, although their importance appears to vary by population group. It notes that shops appear to be a particularly important social space. It also identifies some of the barriers to social interaction within third places and concludes by highlighting some of the key implications for policy to emerge from the research
Deterministic continutation of stochastic metastable equilibria via Lyapunov equations and ellipsoids
Numerical continuation methods for deterministic dynamical systems have been
one of the most successful tools in applied dynamical systems theory.
Continuation techniques have been employed in all branches of the natural
sciences as well as in engineering to analyze ordinary, partial and delay
differential equations. Here we show that the deterministic continuation
algorithm for equilibrium points can be extended to track information about
metastable equilibrium points of stochastic differential equations (SDEs). We
stress that we do not develop a new technical tool but that we combine results
and methods from probability theory, dynamical systems, numerical analysis,
optimization and control theory into an algorithm that augments classical
equilibrium continuation methods. In particular, we use ellipsoids defining
regions of high concentration of sample paths. It is shown that these
ellipsoids and the distances between them can be efficiently calculated using
iterative methods that take advantage of the numerical continuation framework.
We apply our method to a bistable neural competition model and a classical
predator-prey system. Furthermore, we show how global assumptions on the flow
can be incorporated - if they are available - by relating numerical
continuation, Kramers' formula and Rayleigh iteration.Comment: 29 pages, 7 figures [Fig.7 reduced in quality due to arXiv size
restrictions]; v2 - added Section 9 on Kramers' formula, additional
computations, corrected typos, improved explanation
Put on your poker face? Neural systems supporting the anticipation for expressive suppression and cognitive reappraisal
It is a unique human ability to regulate negative thoughts and feelings. Two well-investigated emotion-regulation strategies (ERSs), cognitive reappraisal and expressive suppression, are associated with overlapping prefrontal neural correlates, but differ temporally during the emotion-generation process. Although functional imaging studies have mainly investigated these ERS as a reaction to an emotion-inducing event, the intention to regulate upcoming negative emotions might already be associated with differences in neural activity. Hence, event-related functional magnetic resonance imaging was recorded in 42 participants while they completed an emotion-regulation paradigm. During this task, participants were instructed to proactively prepare to use a specific ERS knowing that a negative, high-arousing image would appear after the preparation period. As expected, the results demonstrated prefrontal and parietal activation while participants were suppressing or reappraising their emotions (family-wise error (FWE)-corrected). The intention to suppress emotions was associated with increased activation in the right inferior frontal gyrus, bilateral putamen, pre-supplementary motor area and right supramarginal gyrus (FWE-corrected). This enhanced proactive inhibitory control: (i) predicted decreased motoric activity during the actual suppression of emotional expressions and (2) trended toward a significant association with how successfully participants suppressed their emotions. However, neural correlates of preparatory control for cognitive reappraisal were not observed, possibly because contextual cues about the upcoming emotional stimulus are necessary to proactively start to cognitively reinterpret the situation
Use of control umbilicals as a deployment mode for free flying telerobotic work systems
Work to date on telerobotic work systems for use in space generally consider two deployment modes, free flying, or fixed within a limited work envelope. Control tethers may be employed to obtain a number of operational advantages and added flexibility in the basing and deployment of telerobotic work systems. Use of a tether allows the work system to be separated into two major modules, the remote work package and the control module. The Remote Work Package (RWP) comprises the free flying portion of the work system while the Control Module (CM) remains at the work system base. The chief advantage of this configuration is that only the components required for completion of the work task must be located at the work site. Reaction mass used in free flight is stored at the Control module and supplied to the RWP through the tether, eliminating the need for the RWP to carry it. The RWP can be made less massive than a self contained free flying work system. As a result, reaction mass required for free flight is lower than for a self contained free flyer
Dependence of Galaxy Shape on Environment in the Sloan Digital Sky Survey
Using a sample of galaxies from the Sloan Digital Sky Survey (SDSS) Data
Release 4, we study the trends relating surface brightness profile type and
apparent axis ratio to the local galaxy environment. We use the SDSS parameter
`fracDeV' to quantify the profile type. We find that galaxies with M_r > -18
are mostly described by exponential profiles in all environments. Galaxies with
-21 < M_r < -18 mainly have exponential profiles in low density environments
and de Vaucouleurs profiles in high density environments. The most luminous
galaxies, with M_r < -21, are mostly described by de Vaucouleurs profiles in
all environments. For galaxies with M_r < -19, the fraction of de Vaucouleurs
galaxies is a monotonically increasing function of local density, while the
fraction of exponential galaxies is monotonically decreasing. For a fixed
surface brightness profile type, apparent axis ratio is frequently correlated
with environment. As the local density of galaxies increases, we find that for
-20 < M_r < -18, galaxies of all profile types become slightly rounder, on
average; for -22 < M_r < -20, galaxies with exponential profiles tend to become
flatter, while galaxies with de Vaucouleurs profiles become rounder; for M_r <
-22, galaxies with exponential profiles become flatter, while the de
Vaucouleurs galaxies become rounder in their inner regions, yet exhibit no
change in their outer regions. We comment on how the observed trends relate to
the merger history of galaxies.Comment: 23 pages, 7 figures, accepted by Ap
Increased signaling entropy in cancer requires the scale-free property of protein interaction networks
One of the key characteristics of cancer cells is an increased phenotypic
plasticity, driven by underlying genetic and epigenetic perturbations. However,
at a systems-level it is unclear how these perturbations give rise to the
observed increased plasticity. Elucidating such systems-level principles is key
for an improved understanding of cancer. Recently, it has been shown that
signaling entropy, an overall measure of signaling pathway promiscuity, and
computable from integrating a sample's gene expression profile with a protein
interaction network, correlates with phenotypic plasticity and is increased in
cancer compared to normal tissue. Here we develop a computational framework for
studying the effects of network perturbations on signaling entropy. We
demonstrate that the increased signaling entropy of cancer is driven by two
factors: (i) the scale-free (or near scale-free) topology of the interaction
network, and (ii) a subtle positive correlation between differential gene
expression and node connectivity. Indeed, we show that if protein interaction
networks were random graphs, described by Poisson degree distributions, that
cancer would generally not exhibit an increased signaling entropy. In summary,
this work exposes a deep connection between cancer, signaling entropy and
interaction network topology.Comment: 20 pages, 5 figures. In Press in Sci Rep 201
Ultrafast spatio-temporal dynamics of terahertz generation by ionizing two-color femtosecond pulses in gases
We present a combined theoretical and experimental study of spatio-temporal
propagation effects in terahertz (THz) generation in gases using two-color
ionizing laser pulses. The observed strong broadening of the THz spectra with
increasing gas pressure reveals the prominent role of spatio-temporal reshaping
and of a plasma-induced blue-shift of the pump pulses in the generation
process. Results obtained from (3+1)-dimensional simulations are in good
agreement with experimental findings and clarify the mechanisms responsible for
THz emission
Measurements of the reverse current of highly irradiated silicon sensors to determine the effective energy and current related damage rate
The reverse current of irradiated silicon sensors leads to self heating of the sensor and degrades the signal to noise ratio of a detector. Precise knowledge of the expected reverse current during detector operation is crucial for planning and running experiments in High Energy Physics. The dependence of the reverse current on sensor temperature and irradiation fluence is parametrized by the effective energy and the current related damage rate, respectively. In this study 18 n-in-p mini silicon strip sensors from companies Hamamatsu Photonics and Micron Semiconductor Ltd. were deployed. Measurements of the reverse current for different bias voltages were performed at temperatures of â32 ° C, â27 ° C and â23 ° C. The sensors were irradiated with reactor neutrons in Ljubljana to fluences ranging from 2Ă1014neqâcm2 to 2Ă1016neqâcm2 . The measurements were performed directly after irradiation and after 10 and 30 days of room temperature annealing. The aim of the study presented in this paper is to investigate the reverse current of silicon sensors for high fluences of up to 2Ă1016neqâcm2 and compare the measurements to the parametrization models
On the use of blow up to study regularizations of singularities of piecewise smooth dynamical systems in
In this paper we use the blow up method of Dumortier and Roussarie
\cite{dumortier_1991,dumortier_1993,dumortier_1996}, in the formulation due to
Krupa and Szmolyan \cite{krupa_extending_2001}, to study the regularization of
singularities of piecewise smooth dynamical systems
\cite{filippov1988differential} in . Using the regularization
method of Sotomayor and Teixeira \cite{Sotomayor96}, first we demonstrate the
power of our approach by considering the case of a fold line. We quickly
recover a main result of Bonet and Seara \cite{reves_regularization_2014} in a
simple manner. Then, for the two-fold singularity, we show that the regularized
system only fully retains the features of the singular canards in the piecewise
smooth system in the cases when the sliding region does not include a full
sector of singular canards. In particular, we show that every locally unique
primary singular canard persists the regularizing perturbation. For the case of
a sector of primary singular canards, we show that the regularized system
contains a canard, provided a certain non-resonance condition holds. Finally,
we provide numerical evidence for the existence of secondary canards near
resonance.Comment: To appear in SIAM Journal of Applied Dynamical System
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