8383 research outputs found
Sort by
An analysis of the L1 scheme for stochastic subdiffusion problem driven by integrated space-time white noise
Get PDFWe consider the strong convergence of the numerical methods for solving stochastic subdiffusion problem driven by an integrated space-time white noise. The time fractional derivative is approximated by using the L1 scheme and the time fractional integral is approximated with the Lubich's first order convolution quadrature formula. We use the Euler method to approximate the noise in time and use the truncated series to approximate the noise in space. The spatial variable is discretized by using the linear finite element method. Applying the idea in Gunzburger \et (Math. Comp. 88(2019), pp. 1715-1741), we express the approximate solutions of the fully discrete scheme by the convolution of the piecewise constant function and the inverse Laplace transform of the resolvent related function. Based on such convolution expressions of the approximate solutions, we obtain the optimal convergence orders of the fully discrete scheme in spatial multi-dimensional cases by using the Laplace transform method and the corresponding resolvent estimates
Machiavelli at 550 — Reflections on his contribution to management, marketing, and public affairs
Get PDFThis is the peer reviewed version of the following article: Harris, P. (2019). Machiavelli at 550—Reflections on his contribution to management, marketing, and public affairs. Journal of Public Affairs, 19(4), e2056., which has been published in final form at https://onlinelibrary.wiley.com/doi/abs/10.1002/pa.2056. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.With the U.K. Elections upon us and manoeuvring for the U.S. Presidential Elections in November 2020 already started, it is time to reflect on power. It is always good to call upon Machiavelli to help make sense of the issues and people in the political arena. It is 550 years since Niccolo Machiavelli was born in Florence in 1469 of a very old Tuscan family. The young Machiavelli had a vigorous humanist education, was taught Latin by good teachers, and had access to the best of classical history and ideas. Little is known about the rest of his life until at the surprisingly young age of 29 in 1498, he was recognised by the Signory for his administrative talents and was elected to the responsible post of Chancellor of the Second Chancery. He is also given duties in the Council of the Ten of Liberty and Peace (formerly Ten of War), which dealt with Florentine foreign affairs
COVID-19 and the UN Security Council: should we expect an intervention?
Get PDFCOVID-19 is a threat to international peace and security under Article 39 of the UN Charter, posing the question where is the UN Security Council? This article explores whether or not we should expect to see the UN Security Council engage the pandemic, and what obstacles may be in the way of such a move
Are Trans diagnostic models of eating disorders fit for purpose? A consideration of the evidence for food addiction
Get PDFThis is the peer reviewed version of the following article: Treasure, J., Leslie, M., Chami, R., Fernandez-Aranda, F. (2018). Are trans diagnostic models of eating disorders fit for purpose? A consideration of the evidence for food addiction. European Eating Disorders Review, 26(2), 83-91. , which has been published in final form at https://onlinelibrary.wiley.com/doi/abs/10.1002/erv.2578. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Explanatory models for eating disorders have changed over time to account for changing clinical presentations. The transdiagnostic model evolved from the maintenance model, which provided the framework for cognitive behavioural therapy for bulimia nervosa. However, for many individuals (especially those at the extreme ends of the weight spectrum), this account does not fully fit. New evidence generated from research framed within the food addiction hypothesis is synthesised here into a model that can explain recurrent binge eating behaviour. New interventions that target core maintenance elements identified within the model may be useful additions to a complex model of treatment for eating disorders
Event-related and readiness potentials when preparing to approach and avoid alcohol cues following cue avoidance training in heavy drinkers.
Get PDFThis is a post-peer-review, pre-copyedit version of an article published in Psychopharmacology. The final authenticated version is available online at: https://doi.org/10.1007/s00213-020-05462-7Rationale Cue avoidance training (CAT) reduces alcohol consumption in the laboratory. However, the neural mechanisms that
underlie the effects of this intervention are poorly understood.
Objectives The present study investigated the effects of a single session of CAT on event-related and readiness potentials during
preparation of approach and avoidance movements to alcohol cues.
Methods Heavy drinking young adults (N = 60) were randomly assigned to complete either CAT or control training. After
training, we recorded participants’ event-related and motor readiness potentials as they were preparing to respond.
Results In the CAT group, N200 amplitude was higher when preparing to approach rather than avoid alcohol pictures. In the
control group, N200 amplitudes did not differ for approach and avoidance to alcohol pictures. Regarding the late positive
potential (LPP), in the CAT group, the negativity of this was blunted when preparing to avoid alcohol pictures relative to when
preparing to avoid control pictures. In the control group, the negativity of the LPP was blunted when preparing to approach
alcohol pictures relative to when preparing to approach control pictures. There were no effects on motor readiness potentials.
Behavioural effects indicated short-lived effects of training on reaction times during the training block that did not persist when
participants were given time to prepare their motor response before executing it during the EEG testing block.
Conclusions After a single session of CAT, the enhanced N200 when approaching alcohol cues may indicate the engagement of
executive control to overcome the associations learned during training. These findings clarify the neural mechanisms that may
underlie the effects of CAT on drinking behaviour
There is no Other Monkey in the Mirror for Spider Monkeys (Ateles geoffroyi)
Get PDF©American Psychological Association, 2020. This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. Please do not copy or cite without author's permission. The final article is available, upon publication, at: https://doi.org/10.1037/com0000243Mirror self-recognition (MSR), usually considered a marker of self-awareness, occurs in several species and may reflect a capacity that has evolved in small incremental steps. In line with research on human development and building on previous research adopting a gradualist framework, we categorized the initial mirror responses of naïve spider monkeys (Ateles geoffroyi) according to four levels. We compared social, exploratory, contingent and self-exploratory responses to a mirror and faux mirror during three short trials. If spider monkeys respond as most monkey species, we predicted they would perform at level 0, mainly showing social behavior toward their mirror-image. However, because spider monkeys show enhancement of certain cognitive skills comparable to those of great ape species, we predicted that they would perform at level 1a (showing exploratory behavior) or 1b (showing contingent behavior). GLMMs revealed that monkeys looked behind and visually inspected the mirror significantly more in the mirror than the faux mirror condition. Although the monkeys engaged in contingent body movements at the mirror, this trend was not significant. Strikingly, they showed no social behaviors toward their mirror-image. We also measured self-scratching as an indicator of anxiety and found no differences in frequencies of self-scratching between conditions. Therefore, in contrast to most findings on other species, spider monkeys did not treat their image as another monkey during their initial exposure to the mirror. In fact, they reached at least level 1a within minutes of mirror exposure. These responses recommend spider monkeys as good candidates for further explorations into monkey self-recognition
Welsh Primary Schoolchildren’s Perceptions of Electronic Cigarettes: A Mixed Methods Study
Get PDFThere are concerns that the growing popularity of e-cigarettes promotes experimentation
among children. Given the influence of the early years on attitude and habit formation, better
understanding of how younger children perceive vaping before experimentation begins is needed,
to prevent uptake and inform tobacco control strategies. We explored Welsh primary schoolchildren’s
(aged 7–11) awareness of e-cigarettes relative to tobacco smoking, their understanding of the
perceived risks and benefits and their intentions and beliefs about vaping. Data was collected using
a mix of methods in June and July 2017 from 8 purposively selected primary schools across Wales.
Four hundred and ninety-five children (52% female) aged 7 years (n = 165), 9 years (n = 185) and
11 years (n = 145) completed a class-administered booklet encompassing a draw and write exercise and
survey. Ninety-six children participated in 24 peer discussion groups comprised of 2 boys and 2 girls
from each year group. Data were analysed independently and findings triangulated. Survey analyses
used frequencies, descriptive statistics and chi-squared tests. Content analysis was undertaken on
the draw and write data and peer discussion groups were analysed thematically. Study findings
highlight that primary schoolchildren have general awareness of e-cigarettes. Vaping was perceived
to be healthier than smoking and there was some recognition that e-cigarettes were used for smoking
cessation. Understanding of any health harms was limited. Few children intended to smoke or
vape in the future but almost half thought it was okay for grownups. Children’s perceptions were
influenced by exposure through family and friends. Findings suggest a need for e-cigarette education
in primary schools, to highlight the associated risks of e-cigarette experimentation including the
potential for tobacco initiation
Modelling transverse matrix cracking and splitting of cross-ply composite laminates under four point bending
No full textThe transverse matrix cracking and splitting in a cross-ply composite laminate has been modelled using the finite element (FE) method with the commercial code Abaqus/Explicit 6.10. The equivalent constraint model (ECM) developed by Soutis et al. has been used for the theoretical prediction of matrix cracking and results have been compared to those obtained experimentally and numerically. A stress-based traction–separation law has been used to simulate the initiation of matrix cracks and their growth under mixed-mode loading. Cohesive elements have been inserted between the interfaces of every neighbouring element along the fibre orientation for all 0° and 90° plies to predict the matrix cracking and splitting at predetermined crack spacing based on experimental observations. Good agreement is obtained between experimental and numerical crack density profiles for different 90° plies. In addition, different mechanisms of matrix cracking and growth processes were captured and splitting was also simulated in the bottom 0° ply by the numerical model
A Compensation Method for Active Phased Array Antennas : Using a Strain-Electromagnetic Coupling Model
No full textPhysical deformation due to service loads seriously degrades the electromagnetic performance of active phased array antennas. However, traditional displacement-based compensation methods are moderately difficult to use because displacement measurements generally require stable references, which are hard to realize for antennas in service. For deformed antennas, strain information is directly related to their displacement, and strain sensors can overcome carrier platform constraints to measure real-time strain without affecting the antenna radiation-field distribution. We thus present a compensation method based on strain information for in-service antennas. First, the minimum number of strain sensors is determined as the main modal-order-based modal effective mass fraction. According to the modal method and analysis of spatial phase-distribution errors related to strain, a coupled strain-electromagnetic model is established to evaluate antenna performance from the measured strain. The corresponding excitation phase from the measured strain is adjusted to compensate antenna performance. Finally, the method is experimentally validated using an X-band active phased array antenna under the influence of typical deformation conditions for both boresightand scanned beams. The results demonstrate that the presented method can effectively compensate for the performance of service antennas directly from the measured strain information
Surface adjustment strategy for a large radio telescope with adjustable dual reflectors
No full textThis paper is a preprint of a paper accepted by IET Microwaves, Antennas and Propagation and is subject to Institution of Engineering and Technology Copyright. When the final version is published, the copy of record will be available at the IET Digital Library.With the development of large-aperture and high-frequency radio telescopes, a surface adjustment procedure for the compensation of surface deformations has become of great importance. In this study, an innovative surface adjustment strategy
is proposed to achieve an automated adjustment for the large radio telescope with adjustable dual reflectors. In the proposed
strategy, a high-precision and long-distance measurement instrument is adopted and installed on the back of the sub-reflector to measure the distances and elevation angles of the target points on the main reflector. Here, two surface adjustment purposes
are discussed. The first purpose is to ensure that the main reflector and sub-reflector are always positioned at their ideal
locations during operation. The second purpose is to adjust the main reflector to the location of the best fitting reflector, and the sub-reflector to the focus of the best fitting reflector. Next, the calculation procedures for the adjustments of the main reflector and the sub-reflector are discussed in detail, and corresponding simulations are carried out to verify the proposed method. The results show that the proposed strategy is effective. This study can provide helpful guidance for the design of automated surface adjustments for large telescopes
Data sources:
Access Repository Dashboard
Do you manage ChesterRep? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!