A connection between the Camassa-Holm equations and turbulent flows in channels and pipes

In this paper we discuss recent progress in using the Camassa-Holm equations to model turbulent flows. The Camassa-Holm equations, given their special geometric and physical properties, appear particularly well suited for studying turbulent flows. We identify the steady solution of the Camassa-Holm equation with the mean flow of the Reynolds equation and compare the results with empirical data for turbulent flows in channels and pipes. The data suggests that the constant $\alpha$ version of the Camassa-Holm equations, derived under the assumptions that the fluctuation statistics are isotropic and homogeneous, holds to order $\alpha$ distance from the boundaries. Near a boundary, these assumptions are no longer valid and the length scale $\alpha$ is seen to depend on the distance to the nearest wall. Thus, a turbulent flow is divided into two regions: the constant $\alpha$ region away from boundaries, and the near wall region. In the near wall region, Reynolds number scaling conditions imply that $\alpha$ decreases as Reynolds number increases. Away from boundaries, these scaling conditions imply $\alpha$ is independent of Reynolds number. Given the agreement with empirical and numerical data, our current work indicates that the Camassa-Holm equations provide a promising theoretical framework from which to understand some turbulent flows.Comment: tex file, 29 pages, 4 figures, Physics of Fluids (in press

Towards an analytical framework of science communication models

This chapter reviews the discussion in science communication circles of models for public communication of science and technology (PCST). It questions the claim that there has been a large-scale shift from a ‘deficit model’ of communication to a ‘dialogue model’, and it demonstrates the survival of the deficit model along with the ambiguities of that model. Similar discussions in related fields of communication, including the critique of dialogue, are briefly sketched. Outlining the complex circumstances governing approaches to PCST, the author argues that communications models often perceived to be opposed can, in fact, coexist when the choices are made explicit. To aid this process, the author proposes an analytical framework of communication models based on deficit, dialogue and participation, including variations on each

The ROTSE-III Robotic Telescope System

The observation of a prompt optical flash from GRB990123 convincingly demonstrated the value of autonomous robotic telescope systems. Pursuing a program of rapid follow-up observations of gamma-ray bursts, the Robotic Optical Transient Search Experiment (ROTSE) has developed a next-generation instrument, ROTSE-III, that will continue the search for fast optical transients. The entire system was designed as an economical robotic facility to be installed at remote sites throughout the world. There are seven major system components: optics, optical tube assembly, CCD camera, telescope mount, enclosure, environmental sensing & protection and data acquisition. Each is described in turn in the hope that the techniques developed here will be useful in similar contexts elsewhere.Comment: 19 pages, including 4 figures. To be published in PASP in January, 2003. PASP Number IP02-11

The ‘credibility paradox’ in China’s science communication: Views from scientific practitioners

In contrast to increasing debates on China’s rising status as a global scientific power, issues of China’s science communication remain under-explored. Based on 21 in-depth interviews in three cities, this article examines Chinese scientists’ accounts of the entangled web of influence which conditions the process of how scientific knowledge achieves (or fails to achieve) its civic authority. A main finding of this study is a ‘credibility paradox’ as a result of the over-politicisation of science and science communication in China. Respondents report that an absence of visible institutional endorsements renders them more public credibility and better communication outcomes. Thus, instead of exploiting formal channels of science communication, scientists interviewed were more keen to act as ‘informal risk communicators’ in grassroots and private events. Chinese scientists’ perspectives on how to earn public support of their research sheds light on the nature and impact of a ‘civic epistemology’ in an authoritarian state

Efficacy and safety of anakinra for undifferentiated autoinflammatory diseases in children: a retrospective case review

Objective: The aim was to carry out a retrospective review of the efficacy and safety of anakinra in paediatric patients with undifferentiated autoinflammatory disease (uAID). Methods: We carried out a retrospective study of children with uAID at a single quaternary centre. The clinical efficacy of anakinra was evaluated using physician global assessment (PGA) and serological response assessed by levels of serum amyloid A and CRP. Safety was assessed by exploring adverse events, including infection and drug reactions. Results: This study included 22 patients, 64% females and 36% males of median age 7.1 years (range 0.13-14.11 years), with uAID. The median starting dose of anakinra was 2 mg/kg (range 2-6 mg/kg) and the median duration of treatment 19.6 months (range 0.8-100 months). Before anakinra treatment, the median PGA, on a three-point Likert scale, was 2 (range 1-2), which fell to 1 (range 0-2) within 3 months of treatment. Eight of 22 (36%) patients achieved complete clinical and serological remission; 8/22 (36%) achieved a partial response; and 6/22 (28%) had no response to anakinra. Adverse events included death (3/22, 14%) and allogeneic haematopoietic stem cell transplantation (1/22, 5%). There were no new safety signals, and anakinra was well tolerated overall. Conclusion: Retrospectively, 72% of children with uAID responded well to anakinra, with 36% achieving full clinical and serological remission within 3 months. This suggests that empirical trials of IL-1 blockade might be warranted in children with uAID. Clear stopping criteria based on predefined parameters should be considered, because non-responders required alternative therapies, facilitated by a definitive molecular diagnosis where possible

Future local passenger transport system scenarios and implications for policy and practice

The world is rapidly changing and the future is uncertain, yet until recently the dominant assumption of the local passenger transport community has been that the existing modal landscape of cars, buses and taxis will remain much as it is now. Such a view is now shifting however, with decision makers now appreciating the need to understand the implications of potentially radical changes in the technological, political, economic, social and environmental spheres. Accordingly, in August 2015 the Public Transport 2045 study was commissioned to consider how different local public transport futures might affect society over the next 30-years, and at how governments might best respond. The multi-phase study was based on individual in-depth interviews with 50 senior local passenger transport operators, government officials, lobbyists and experts from New Zealand and around the world; and four validation workshops with 28 sector stakeholders. The data was analysed using mostly pre-determined themes from which four scenarios were constructed and then validated. The implications are that the transport system is about to transition to a system of ‘shared mobility’; public transport will need to evolve to stay relevant but will remain important in any scenario; and the role of Government will be vital in overseeing the transition to the shared mobility era. These lessons are now being used to inform transport and broader policy decisions across New Zealand. Overall, the study is the first to apply such a global and qualitatively rich dataset to view the long-term future passenger transport system as a whole

Safeguarding children in dentistry: 1. Child protection training, experience and practice of dental professionals with an interest in paediatric dentistry

* Few dental professionals with child protection training have experience of making referrals. * There is a wide gap in practice between recognising signs of child abuse and neglect and responding effectively. * This may indicate missed opportunities to save children from continuing abuse. * There is a need for improved child protection information, support and training for dental professionals. Abstract Following several highly publicised inquiries into the deaths of children from abuse and neglect, there has been much recent interest in the role and responsibility of all health professionals to protect children at risk of maltreatment. The findings of a postal questionnaire, sent in March 2005 to 789 dentists and dental care professionals with an interest in paediatric dentistry working in varied settings in the UK, are presented in a two-part report and discussed in the context of current multi-agency good practice in safeguarding and promoting the welfare of children. This first part explores reported child protection training, experience and practice. There was a significant gap between recognising signs of abuse and responding effectively: 67% of respondents had suspected abuse or neglect of a child patient at some time in their career but only 29% had ever made a child protection referral. The dental profession is alerted to the need to ensure necessary appropriate action to safeguard children is always taken when child abuse or neglect are suspected

Relationship between quantum decoherence times and solvation dynamics in condensed phase chemical systems

A relationship between the time scales of quantum coherence loss and short-time solvent response for a solute/bath system is derived for a Gaussian wave packet approximation for the bath. Decoherence and solvent response times are shown to be directly proportional to each other, with the proportionality coefficient given by the ratio of the thermal energy fluctuations to the fluctuations in the system-bath coupling. The relationship allows the prediction of decoherence times for condensed phase chemical systems from well developed experimental methods.Comment: 10 pages, no figures, late

A Pair of Compact Red Galaxies at Redshift 2.38, Immersed in a 100 kpc Scale Ly-alpha Nebula

We present Hubble Space Telescope (HST) and ground-based observations of a pair of galaxies at redshift 2.38, which are collectively known as 2142-4420 B1 (Francis et al. 1996). The two galaxies are both luminous extremely red objects (EROs), separated by 0.8 arcsec. They are embedded within a 100 kpc scale diffuse Ly-alpha nebula (or blob) of luminosity ~10^44 erg/s. The radial profiles and colors of both red objects are most naturally explained if they are young elliptical galaxies: the most distant yet found. It is not, however, possible to rule out a model in which they are abnormally compact, extremely dusty starbursting disk galaxies. If they are elliptical galaxies, their stellar populations have inferred masses of ~10^11 solar masses and ages of ~7x10^8 years. Both galaxies have color gradients: their centers are significantly bluer than their outer regions. The surface brightness of both galaxies is roughly an order of magnitude greater than would be predicted by the Kormendy relation. A chain of diffuse star formation extending 1 arcsec from the galaxies may be evidence that they are interacting or merging. The Ly-alpha nebula surrounding the galaxies shows apparent velocity substructure of amplitude ~ 700 km/s. We propose that the Ly-alpha emission from this nebula may be produced by fast shocks, powered either by a galactic superwind or by the release of gravitational potential energy.Comment: 33 pages, 9 figures, ApJ in press (to appear in Jun 10 issue