Kolmogorov turbulence in a random-force-driven Burgers equation

The dynamics of velocity fluctuations, governed by the one-dimensional Burgers equation, driven by a white-in-time random force with the spatial spectrum \overline{|f(k)|^2}\proptok^{-1}, is considered. High-resolution numerical experiments conducted in this work give the energy spectrum $E(k)\propto k^{-\beta}$ with $\beta =5/3\pm 0.02$. The observed two-point correlation function $C(k,\omega)$ reveals $\omega\propto k^z$ with the "dynamical exponent" $z\approx 2/3$. High-order moments of velocity differences show strong intermittency and are dominated by powerful large-scale shocks. The results are compared with predictions of the one-loop renormalized perturbation expansion.Comment: 13 LaTeX pages, psfig.sty macros, Phys. Rev. E 51, R2739 (1995)

Beyond scaling and locality in turbulence

An analytic perturbation theory is suggested in order to find finite-size corrections to the scaling power laws. In the frame of this theory it is shown that the first order finite-size correction to the scaling power laws has following form $S(r) \cong cr^{\alpha_0}[\ln(r/\eta)]^{\alpha_1}$, where $\eta$ is a finite-size scale (in particular for turbulence, it can be the Kolmogorov dissipation scale). Using data of laboratory experiments and numerical simulations it is shown shown that a degenerate case with $\alpha_0 =0$ can describe turbulence statistics in the near-dissipation range $r > \eta$, where the ordinary (power-law) scaling does not apply. For moderate Reynolds numbers the degenerate scaling range covers almost the entire range of scales of velocity structure functions (the log-corrections apply to finite Reynolds number). Interplay between local and non-local regimes has been considered as a possible hydrodynamic mechanism providing the basis for the degenerate scaling of structure functions and extended self-similarity. These results have been also expanded on passive scalar mixing in turbulence. Overlapping phenomenon between local and non-local regimes and a relation between position of maximum of the generalized energy input rate and the actual crossover scale between these regimes are briefly discussed.Comment: extended versio

Sources and Coverage of Medical News on Front Pages of US Newspapers

Background: Medical news that appears on newspaper front pages is intended to reach a wide audience, but how this type of medical news is prepared and distributed has not been systematically researched. We thus quantified the level of visibility achieved by front-page medical stories in the United States and analyzed their news sources. Methodology: Using the online resource Newseum, we investigated front-page newspaper coverage of four prominent medical stories, and a high-profile non-medical news story as a control, reported in the US in 2007. Two characteristics were quantified by two raters: which newspaper titles carried each target front-page story (interrater agreement, >96%; kappa, >0.92) and the news sources of each target story (interrater agreement, >94%; kappa, >0.91). National rankings of the top 200 US newspapers by audited circulation were used to quantify the extent of coverage as the proportion of the total circulation of ranked newspapers in Newseum. Findings: In total, 1630 front pages were searched. Each medical story appeared on the front pages of 85 to 117 (67.5%-78.7%) ranked newspaper titles that had a cumulative daily circulation of 23.1 to 33.4 million, or 61.8% to 88.4% of all newspapers. In contrast, the non-medical story achieved front-page coverage in 152 (99.3%) newspaper titles with a total circulation of 41.0 million, or 99.8% of all newspapers. Front-page medical stories varied in their sources, but the Washington Post, Los Angeles Times, New York Times and the Associated Press together supplied 61.7% of the total coverage of target front-page medical stories. Conclusion: Front-page coverage of medical news from different sources is more accurately revealed by analysis of circulation counts rather than of newspaper titles. Journals wishing to widen knowledge of research news and organizations with important health announcements should target at least the four dominant media organizations identified in this study

Regulating CCTV? : We can't solve problems by using the same kind of thinking we used when we created them

Peer reviewedPostprin

Fully developed turbulence and the multifractal conjecture

We review the Parisi-Frisch MultiFractal formalism for Navier--Stokes turbulence with particular emphasis on the issue of statistical fluctuations of the dissipative scale. We do it for both Eulerian and Lagrangian Turbulence. We also show new results concerning the application of the formalism to the case of Shell Models for turbulence. The latter case will allow us to discuss the issue of Reynolds number dependence and the role played by vorticity and vortex filaments in real turbulent flows.Comment: Special Issue dedicated to E. Brezin and G. Paris

Ideological cultures and media discourses on scientific knowledge: re-reading news on climate change

Focusing on the representation of climate change in the British “quality press,” this article argues that the discursive (re)construction of scientific claims in the media is strongly entangled with ideological standpoints. Understood here as a set of ideas and values that legitimate a program of action vis-à-vis a given social and political order, ideology works as a powerful selection device in deciding what is scientific news, i.e. what the relevant “facts” are, and who are the authorized “agents of definition” of science matters. The representation of scientific knowledge has important implications for evaluating political programs and assessing the responsibility of both governments and the public in addressing climate change

Lay perceptions of evidence-based information – a qualitative evaluation of a website for back pain sufferers

BACKGROUND: In an evidence-informed patient choice the patient has access to research-based information about the effectiveness of health care options and is encouraged to use this information in treatment decisions. This concept has seen growing popularity in recent years. However, we still know relatively little about users' attitudes to the use of research-based information, possibly because people have been unexposed to this type of information. After developing the BackInfo website where the results of Cochrane systematic reviews on the effects of low back pain were adapted and presented to lay users we evaluated how users responded to this information. METHODS: Focus group meetings were held with 18 chronic back pain sufferers, after they had been sent a link to the website before the meetings. RESULTS: The focus groups suggest that the most important challenges to the use of BackInfo's research-based information are not primarily tied to the comprehension or presentation of the information, but are mainly associated with participants' attitudes towards the credibility of research and researchers, and the applicability of research results to themselves as individuals. Possible explanations for participants' lack of trust in research and their apparent difficulties in applying this research to their own situations include aspects that may be typical for the general public including the media's presentation of research, and a lack of familiarity with and feelings of distance to research evidence. Other aspects may be typical for patient groups with chronic and unclear medical conditions, such as a lack of trust in the health care establishment in general. CONCLUSION: In order to enhance the credibility and applicability of research evidence, providers of research-based information could explore a number of possibilities including the use of including personal stories to illustrate the research outcomes

Candidate knowledge? Exploring epistemic claims in scientific writing:a corpus-driven approach

In this article I argue that the study of the linguistic aspects of epistemology has become unhelpfully focused on the corpus-based study of hedging and that a corpus-driven approach can help to improve upon this. Through focusing on a corpus of texts from one discourse community (that of genetics) and identifying frequent tri-lexical clusters containing highly frequent lexical items identified as keywords, I undertake an inductive analysis identifying patterns of epistemic significance. Several of these patterns are shown to be hedging devices and the whole corpus frequencies of the most salient of these, candidate and putative, are then compared to the whole corpus frequencies for comparable wordforms and clusters of epistemic significance. Finally I interviewed a ‘friendly geneticist’ in order to check my interpretation of some of the terms used and to get an expert interpretation of the overall findings. In summary I argue that the highly unexpected patterns of hedging found in genetics demonstrate the value of adopting a corpus-driven approach and constitute an advance in our current understanding of how to approach the relationship between language and epistemology

Alternatives and responsibility: an asymmetrical approach

En este trabajo defiendo una visión asimétrica sobre la relación entre las posibilidades alternativas y la responsabilidad moral, según la cual se requiere tener posibilidades alternativas para ser culpable por lo que uno decide o hace, pero no para ser laudable por ello. Defiendo la no necesidad de alternativas para ser laudable a través de un examen de lo que yo llamo “ejemplos Lutero”. Mi defensa de la necesidad de alternativas para ser culpable procede en cambio mediante un análisis de los llamados “casos Frankfurt”. En ambos casos, mis argumentos se basan en la afirmación según la cual, en las adscripciones de responsabilidad moral, la cuestión principal no es si el agente podría haber hecho algo distinto, sino si debería haber hecho lo que hizo, de modo que la primera pregunta solo se vuelve apremiante cuando la respuesta a la segunda es negativa. Así, pues, en lo que se refiere a la responsabilidad moral, el concepto de obligación o deber moral es previo al de posibilidades alternativas.In this paper, I defend an asymmetrical view concerning the relationship between alternative possibilities and moral responsibility, according to which alternative possibilities are required for being blameworthy, but not praiseworthy, for what one decides or does. I defend the non-necessity of alternatives for praiseworthiness through an examination of what I call ‘Luther’ examples. My defence of the necessity of alternatives for blameworthiness proceeds instead through an analysis of so-called ‘Frankfurt’ examples. In both cases, my arguments rest on the contention that, in ascriptions of moral responsibility, the primary question is not whether the agent could have done otherwise, but whether she should have done what she did, so that the former question only becomes pressing when the answer to the latter is negative. Concerning moral responsibility, then, the concept of moral obligation or duty is prior to that of alternative possibilities