3,468 research outputs found
Time-Domain Simulation of Mixed Nonlinear Magnetic and Electronic Systems
This paper describes a technique for the simulation of complex magnetic systems intimately connected to any necessary drive electronics. The system is split into two Kirchhoffian domains, one magnetic and one electric. Two-way interaction between the domains is supported by a virtual device called a magneto-electric differential gyrator. Using this technique, arbitrarily complex, non-linear, hysteretic magnetic systems may be simulated in the time domain, coupled to any appropriate non-linear electronics, at a fraction of the cost of a comparable finite element calculation. The capabilities of the system are demonstrated by the simulation of a feedback-controlled current sensing system, and the simulation tracks the measured behaviour of the system well outside its linear region, to the point that the non-linear hysteretic core is being driven into and out of saturation, a consequence of a time delay inherent in the electronics. This is compared with a simulation of the same system using a 'conventional' electronic simulation, and the increased accuracy of this technique clearly demonstrated
Connecting low- and high-mass star formation: the intermediate-mass protostar IRAS 05373+2349 VLAÂ 2
Until recently, there have been few studies of the protostellar evolution of intermediate-mass (IM) stars, which may bridge the low- and high-mass regimes. This paper aims to investigate whether the properties of an IM protostar within the IRAS 05373+2349 embedded cluster are similar to that of low- and/or high-mass protostars. We carried out Very Large Array as well as Combined Array for Research in Millimeter Astronomy continuum and 12CO(J=1â0) observations, which uncover seven radio continuum sources (VLA 1â7). The spectral index of VLA 2, associated with the IM protostar is consistent with an ionized stellar wind or jet. The source VLA 3 is coincident with previously observed H2 emission line objects aligned in the northâsouth direction (P.A. â20 to â12âŠ), which may be either an ionized jet emanating from VLA 2 or (shock-)ionized cavity walls in the large-scale outflow from VLA 2. The position angle between VLA 2 and 3 is slightly misaligned with the large-scale outflow we map at âŒ5-arcsec resolution in 12CO (P.A. âŒ30âŠ), which in the case of a jet suggests precession. The emission from the mm core associated with VLA 2 is also detected; we estimate its mass to be 12â23 M , depending on the contribution from ionized gas. Furthermore, the large-scale outflow has properties intermediate between outflows from low- and high-mass young stars. Therefore, we conclude that the IM protostar within IRAS 05373+2349 is phenomenologically as well as quantitatively intermediate between the low- and high-mass domains
Initiation and slow propagation of epileptiform activity from ventral to dorsal medial entorhinal cortex is constrained by an inhibitory gradient.
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The medial entorhinal cortex (mEC) has an important role in the generation and propagation of seizure activity. The organisation of the mEC is such that a number of dorso-ventral relationships exist in neurophysiological properties of neurons. These range from intrinsic and synaptic properties to density of inhibitory connectivity. We examined the influence of these gradients on generation and propagation of epileptiform activity in the mEC. Using a 16-shank silicon probe array to record along the dorso-ventral axis of the mEC in vitro, we found 4-aminopyridine (4-AP) application produces ictal-like activity originating predominantly in ventral areas. This activity spreads to dorsal mEC at a surprisingly slow velocity (138Â ÎŒm.s-1), while cross-site interictal-like activity appeared relatively synchronous. We propose that ictal propagation is constrained by differential levels of GABAergic control since increasing (diazepam) or decreasing (Ro19-4603) GABAAreceptor activation, respectively, reduced or increased the slope of ictal initiation. The observation that ictal activity is predominately generated in ventral mEC was replicated using a separate 0-Mg2+model of epileptiform activity in vitro. By using a distinct disinhibition model (co-application of kainate and picrotoxin) we show that additional physiological features (for example intrinsic properties of mEC neurons) still produce a prevalence for interictal-like initiation in ventral mEC. These findings suggest that the ventral mEC is more likely to initiate hyperexcitable discharges than dorsal, and that seizure propagation is highly dependent on levels of GABAergic expression across the mEC. This article is protected by copyright. All rights reserved.This work was supported by a University of Exeter and Eli Lilly studentship (T.R). P.M 513 was supported by an MRC Proximity to Discovery award in partnership with 514 AstraZeneca. K.G.P was an employee of Eli Lilly. A.D.R was part funded by a Royal 515 Society Industrial Fellowship. J.T.B was an Alzheimerâs Research UK Senior Research 516 Fellow (ARUK-SRF2012-6)
Towards a new theory of practice for community health psychology
The article sets out the value of theorizing collective action from a social science perspective that engages with the messy actuality of practice. It argues that community health psychology relies on an abstract version of Paulo Freireâs earlier writing, the Pedagogy of the Oppressed, which provides scholar-activists with a âmapâ approach to collective action. The article revisits Freireâs later work, the Pedagogy of Hope, and argues for the importance of developing a âjourneyâ approach to collective action. Theories of practice are discussed for their value in theorizing such journeys, and in bringing maps (intentions) and journeys (actuality) closer together
Inner wellbeing: concept and validation of a new approach to subjective perceptions of wellbeing-India
© The Author(s) 2013. This article is published with open access at Springerlink.com. 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 paper describes the conceptual development of a multi-domain, psychosocial model of 'Inner Wellbeing' (IWB) and assesses the construct validity of the scale designed to measure it. IWB expresses what people think and feel they are able to be and do. Drawing together scholarship in wellbeing and international development it is grounded in field research in marginalised, rural communities in the global South. Results from research in India at two points in time (2011 and 2013) are reported. At Time 1 (n = 287), we were unable to confirm an eight-factor, correlated model as distinct yet interrelated domains. However, at Time 2 (n = 335), we were able to confirm a revised, seven-factor correlated model with economic confidence, agency and participation, social connections, close relationships, physical and mental health, competence and self-worth, and values and meaning (five items per domain) as distinct yet interrelated domains. In particular, at Time 2, a seven-factor, correlated model provided a significantly better fit to the data than did a one-factor model.This work is supported by the Economic and Social Research Council/Department for
International Development Joint Scheme for Research on International Development (Poverty Alleviation)
grant number RES-167-25-0507 ES/H033769/1. Special thanks are due to Chaupal and Gangaram Paikra,
Pritam Das, Usha Kujur, Kanti Minjh, Susanna Siddiqui, and Dinesh Tirkey
From social context and resilience to performance through job satisfaction: A multilevel study over time
Giving the crucial role of organizational context in shaping individual attitudes and behaviors at work, in this research we studied the effects of collective work-unit Perceptions of Social Context (PoSC) on individual work resilience and two key individual outcomes: job satisfaction and job performance as rated by the supervisor. We theorized that collective PoSC act as antecedents of individual variables, and that individual job satisfaction mediates the relationship between collective PoSC and job performance, and between work resilience and job performance over time. A sample of 305 white-collar employees, clustered in 67 work-units, participated in the study. Hierarchical linear modeling highlighted that collective PoSC are significant related to individual work resilience. Moreover, results showed that individual job satisfaction fully mediates the relationship between collective PoSC and individual job performance and the relationship between individual work resilience and individual job performance. At a practical level, results suggest that interventions on collective PoSC may increase work resilience, job satisfaction and job performance over time at the individual level
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The consent process: enabling or disabling patientsâ active participation?
Standards expected by doctorsâ regulatory bodies in respect of the process of consent to treatment have arguably sought to restructure the nature of the doctor-patient relationship from one of paternalism to that of shared decision-making. Yet, few studies have explored empirically, from patientsâ perspectives, the extent to which the process of consent to treatment enables or disables patientsâ participation in medical decision-making. Our paper examines patientsâ attitudes towards the consent process, exploring how and why these attitudes influence patientsâ active participation in decision-making and considering possible consequent medico-legal issues. Data were collected longitudinally using semi-structured interviews and field observations involving 35 patients and 19 of their caregivers, in an English hospital between February and November 2014. These indicate that generally patients defer to the doctor in respect of treatment decision-making. Although most patients and their caregivers wanted detailed information and discussion, they did not necessarily expect that this would be provided. Further, patients perceived that signing the consent form was an obligatory routine principally to protect doctors from legal action should something go wrong. Our study suggests that patientsâ predominantly paternalistic perceptions of the consent process can not only undermine attempts by doctors to involve them in decision-making but, as patients are now considered in law as informed actors, their perceptions of the consent form as not being in their interests could be a self-fulfilling prophecy if signing is undertaken without due consideration to the content
Impaired speed encoding and grid cell periodicity in a mouse model of tauopathy
This is the final version. Available on open access from eLife Sciences Publications via the DOI in this record.âŻDementia is associated with severe spatial memory deficits which arise from dysfunction in hippocampal and parahippocampal circuits. For spatially sensitive neurons, such as grid cells, to faithfully represent the environment these circuits require precise encoding of direction and velocity information. Here, we have probed the firing rate coding properties of neurons in medial entorhinal cortex (MEC) in a mouse model of tauopathy. We find that grid cell firing patterns are largely absent in rTg4510 mice, while head-direction tuning remains largely intact. Conversely, neural representation of running speed information was significantly disturbed, with smaller proportions of MEC cells having firing rates correlated with locomotion in rTg4510 mice. Additionally, the power of local field potential oscillations in the theta and gamma frequency bands, which in wild-type mice are tightly linked to running speed, was invariant in rTg4510 mice during locomotion. These deficits in locomotor speed encoding likely severely impact path integration systems in dementia.Alzheimerâs Research U
General Form of the Color Potential Produced by Color Charges of the Quark
Constant electric charge satisfies the continuity equation where is the current density of the electron.
However, the Yang-Mills color current density of the quark
satisfies the equation which is not a continuity
equation () which implies that a color charge
of the quark is not constant but it is time dependent where
are color indices. In this paper we derive general form of color
potential produced by color charges of the quark. We find that the general form
of the color potential produced by the color charges of the quark at rest is
given by \Phi^a(x) =A_0^a(t,{\bf x}) =\frac{q^b(t-\frac{r}{c})}{r}\[\frac{{\rm
exp}[g\int dr \frac{Q(t-\frac{r}{c})}{r}] -1}{g \int dr
\frac{Q(t-\frac{r}{c})}{r}}\]_{ab} where integration is an indefinite
integration, ~~ , ~~, ~~ is the retarded time, ~~ is the speed
of light, ~~ is the position of the quark at the retarded
time and the repeated color indices (=1,2,...8) are summed. For constant
color charge we reproduce the Coulomb-like potential
which is consistent with the Maxwell theory where
constant electric charge produces the Coulomb potential
.Comment: Final version, two more sections added, 45 pages latex, accepted for
publication in JHE
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