2,525 research outputs found

    Dynamically-Coupled Oscillators -- Cooperative Behavior via Dynamical Interaction --

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    We propose a theoretical framework to study the cooperative behavior of dynamically coupled oscillators (DCOs) that possess dynamical interactions. Then, to understand synchronization phenomena in networks of interneurons which possess inhibitory interactions, we propose a DCO model with dynamics of interactions that tend to cause 180-degree phase lags. Employing an approach developed here, we demonstrate that although our model displays synchronization at high frequencies, it does not exhibit synchronization at low frequencies because this dynamical interaction does not cause a phase lag sufficiently large to cancel the effect of the inhibition. We interpret the disappearance of synchronization in our model with decreasing frequency as describing the breakdown of synchronization in the interneuron network of the CA1 area below the critical frequency of 20 Hz.Comment: 10 pages, 3 figure

    Electron-beam propagation in a two-dimensional electron gas

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    A quantum mechanical model based on a Green's function approach has been used to calculate the transmission probability of electrons traversing a two-dimensional electron gas injected and detected via mode-selective quantum point contacts. Two-dimensional scattering potentials, back-scattering, and temperature effects were included in order to compare the calculated results with experimentally observed interference patterns. The results yield detailed information about the distribution, size, and the energetic height of the scattering potentials.Comment: 7 pages, 6 figure

    Preferences for Medical Consultations from Online Providers: Evidence from a Discrete Choice Experiment in the United Kingdom

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    Background: In the UK, consultations for prescription medicines are available via private providers such as online pharmacies. However, these providers may have lower thresholds for prescribing certain drugs. This is a particular concern for antibiotics, given the increasing burden of antimicrobial resistance. Public preferences for consultations with online providers are unknown, hence the impact of increased availability of online consultations on antibiotic use and population health is unclear. Objective: To conduct a discrete choice experiment survey to understand UK public preferences for seeking online consultations, and the factors that influence these preferences, in the context of having symptoms for which antibiotics may be appropriate. Methods: In a survey conducted between July and August 2018, general population respondents completed 16 questions in which they chose a primary care consultation via either their local medical centre or an online provider. Consultations were described in terms of five attributes, including cost and similarity to traditional ‘face-to-face’ appointments. Choices were modelled using regression analysis. Results: Respondents (n = 734) placed a high value on having a consultation via their local medical centre rather than an online provider, and a low value on consultations by phone or video. However, respondents characterised as ‘busy young professionals’ showed a lower strength of preference for traditional consultations, with a higher concern for convenience. Conclusion: Before COVID-19, the UK public had limited appetite for consultations with online providers, or for consultations that were not face-to-face. Nevertheless, prescriptions from online providers should be monitored going forward, particularly for antibiotics, and in key patient groups

    External and internal noise surveys of London primary schools

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    Internal and external noise surveys have been carried out around schools in London, UK, to provide information on typical levels and sources to which children are exposed while at school. Noise levels were measured outside 142 schools, in areas away from flightpaths into major airports. 86% of the schools surveyed were exposed to noise from road traffic, the average external noise level outside a school being 57 dB LAeq. Detailed internal noise surveys have been carried out in 140 classrooms in 16 schools, together with classroom observations. It was found that noise levels inside classrooms depend upon the activities in which the children are engaged, with a difference of 20 dB LAeq between the 'quietest' and 'noisiest' activities. The average background noise level in classrooms exceeds the level recommended in current standards. The number of children in the classroom was found to affect noise levels. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities. The effects of the age of the school buildings and types of window upon internal noise were examined but results were inconclusive

    Cryosurgery Versus Primary Androgen Deprivation Therapy for Locally Recurrent Prostate Cancer After Primary Radiotherapy: A Propensity-Matched Survival Analysis.

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    Background Optimal management of isolated local recurrence of prostate cancer after primary radiotherapy remains to be defined. Up-front androgen deprivation therapy (ADT) is widely used but may adversely affect the quality of life and is essentially a palliative treatment. Local salvage carries a different side-effect profile and is potentially curative, but it has not been compared to ADT. Materials and methods We conducted a propensity-matched analysis of cohorts of men treated with either whole gland cryotherapy (CRYO) or primary ADT following the diagnosis of locally recurrent prostate cancer. Our specific objectives were to compare overall survival (OS) and prostate cancer-specific mortality (PCSM) between CRYO vs. ADT. Results After a one-to-one matching, 169 patients from each cohort were included in comparisons. Median follow-up time was 6.7 years (ADT) vs. 18 years (CRYO). The 10-year PCSM was 18.5% (ADT) vs. 16.2% (CRYO), which was not statistically different [hazard ratioo (HR): 0.69, 95% CI: 0.36-1.34, p=0.27]. The median OS was 12.3 years (CRYO) versus 10.2 years (ADT) (HR: 0.63, 95% CI: 0.42-0.95, p=0.03). Conclusions While PCSM was similar between the two strategies, CRYO was associated with a longer OS compared to primary ADT. Given the retrospective nature of the trial, these results should be considered hypothesis-generating, and phase III trials comparing these two options are required to further explore these findings

    From multiple perspectives to shared understanding

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    The aim of this study was to explore how learners operating in a small group reach shared understanding as they work out joint research questions and build a theoretical framework and to identify the resources and tools they used in the process. The learners’ own interpretations of their group activities and learning were also taken into account. The data, consisting of group discussions and the documents produced by the group, were subjected to a qualitative content analysis. The group members employed a variety of resources and tools to exchange their individual perspectives and achieve shared understanding. Summaries of relevant literature laid a foundation for the group’s theoretical discussions. Reflective comparisons between their book knowledge and their personal experiences of online interaction and collaboration were frequent, suggesting that such juxtapositions may have enhanced their learning by intertwining the content to be mastered and the activities entailed by this particular content

    p73 is over-expressed in vulval cancer principally as the Δ2 isoform

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    p73 was studied in squamous cancers and precursor lesions of the vulva. Over-expression of p73 occurred commonly in both human papillomavirus (HPV)-positive and -negative squamous cell cancers (SCC) and high-grade premalignant lesions. Whereas expression in normal vulval epithelium was detected only in the basal and supra-basal layers, expression in neoplastic epithelium increased with grade of neoplasia, being maximal at both protein and RNA levels in SCC. p73 Δ2 was the principal over-expressed isoform in the majority of cases of vulval SCC and often the sole form expressed in SCC. Over-expression of p73 was associated with expression of HPV-encoded E7 or with hypermethylation or mutation of p16INK4a in HPV-negative cases. There was a close correlation between expression of p73 and p14ARF in cancers with loss of p53 function. The frequent over-expression of p73 Δ2 in neoplastic but not normal vulval epithelium, and its co-ordinate deregulation with other E2F-1 responsive genes suggests a role in the oncogenic process. © 2001 Cancer Research Campaign  http://www.bjcancer.co

    The arcade project

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    The Atmospheric Research for Climate and Astroparticle Detection (ARCADE) project aims to a better comprehension of the limits of applicability, systematics and possible enhancements of the typical techniques used for the measurement of the aerosol attenuation profiles of UV light in cosmic rays and gamma rays experiments. Aerosols are indeed the most variable component in the atmosphere on a short time scale, and experiments based on the detection of the UV light in atmosphere need a continuous monitoring of the aerosol stratification to obtain a reliable evaluation of the properties of the primary particles. The ARCADE project is measuring the aerosol attenuation of UV light due to aerosols with multiple techniques and instruments simultaneously on the same air mass. For this purpose, a Raman + elastic Lidar with a laser source at 355 nm has been built and is currently taking data in Lamar, Colorado together with the Atmospheric Monitoring Telescope (AMT) to detect UV light at a distance of 40 km from the Lidar laser source. The system has been installed on site in 2014 and data were taken every month during moonless nights for one year. A full simulation of the AMT system has been developed. The setup and simulation of the system, together with the AMT calibration system and first collected data are shown
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