Diffusive and localization behavior of electromagnetic waves in a two-dimensional random medium

In this paper, we discuss the transport phenomena of electromagnetic waves in a two-dimensional random system which is composed of arrays of electrical dipoles, following the model presented earlier by Erdogan, et al. (J. Opt. Soc. Am. B {\bf 10}, 391 (1993)). A set of self-consistent equations is presented, accounting for the multiple scattering in the system, and is then solved numerically. A strong localization regime is discovered in the frequency domain. The transport properties within, near the edge of and nearly outside the localization regime are investigated for different parameters such as filling factor and system size. The results show that within the localization regime, waves are trapped near the transmitting source. Meanwhile, the diffusive waves follow an intuitive but expected picture. That is, they increase with travelling path as more and more random scattering incurs, followed by a saturation, then start to decay exponentially when the travelling path is large enough, signifying the localization effect. For the cases that the frequencies are near the boundary of or outside the localization regime, the results of diffusive waves are compared with the diffusion approximation, showing less encouraging agreement as in other systems (Asatryan, et al., Phys. Rev. E {\bf 67}, 036605 (2003).)Comment: 8 pages 9 figure

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

Sedimentology of gas-bearing Devonian shales of the Appalachian Basin

The Eastern Gas Shales Project (1976-1981) of the US DOE has generated a large amount of information on Devonian shale, especially in the western and central parts of the Appalachian Basin (Morgantown Energy Technology Center, 1980). This report summarizes this information, emphasizing the sedimentology of the shales and how it is related to gas, oil, and uranium. This information is reported in a series of statements each followed by a brief summary of supporting evidence or discussion and, where interpretations differ from our own, we include them. We believe this format is the most efficient way to learn about the gas-bearing Devonian shales of the Appalachian Basin and have organized our statements as follows: paleogeography and basin analysis; lithology and internal stratigraphy; paleontology; mineralogy, petrology, and chemistry; and gas, oil, and uranium

Influence of early prehospital thrombolysis on mortality and event-free survival (The myocardial infarction triage and intervention [MITI]randomized trial)

Contains fulltext : 24122___.PDF (publisher's version ) (Open Access

Optical coherent backscattering by random media : an experimental study

A detailed experimental study of coherent backscattering of light from aqueous suspensions of polystyrene microspheres is presented. Emphasis is on the effects of particle size, of absorption due to added dye and of light polarization on the shape and height of the backscattering cone. For parallel polarization of incident and scattered beams, the scalar diffusion theory, parametrized by the transport mean free path l*, agrees well with our data up to surprizingly large scattering angles (ql * ~ 1) and quantitatively accounts for the rounding of the cones due to absorption. No deviations from the usual Gaussian statistics of scattered fields is observed up to λ/l* ∼ 0.1.Nous présentons une étude détaillée de la rétrodiffusion cohérente de la lumière par des suspensions aqueuses de microbilles de polystyrène. Nous discutons particulièrement les effets, sur la forme et la hauteur du pic de rétrodiffusion, de la taille des particules, de l'absorption — contrôlée par l'addition d'un colorant — et de la polarisation de la lumière. Lorsque les polarisations incidente et détectée sont parallèles, la théorie de diffusion scalaire, caractérisée par le libre parcours moyen de transport l *, rend compte de la forme du pic jusqu'à des angles de (rétro)diffusion étonnement élevés (ql * ~ 1) et de son arrondissement progressif en présence d'absorption. Nous n'observons aucune déviation à la statistique gaussienne habituelle pour le champ diffusé, et ce jusqu'à des rapports λ/l* ∼ 0,1

Theoretical study of the coherent backscattering of light by disordered media

A theoretical study of the coherent backscattering effect of light from disordered semi-infinite media is presented for various situations including time-dependent effects as well as absorption and amplitude modulation. Particular attention is devoted to the case of anisotropic scattering and to polarization in order to explain quantitatively experimental results. A microscopic derivation of the coherent albedo is given which strongly supports the heuristic formula previously established. In addition the coherent albedo of a fractal system is predicted. The validity of the different approximations used are discussed and some further theoretical developments are presented.Nous présentons une étude théorique de la rétrodiffusion cohérente de la lumière par un milieu désordonné dans diverses situations incluant les effets dépendant du temps, les milieux absorbants et les effets liés à la modulation d'amplitude de la lumière. Nous discutons tout particulièrement le cas de la diffusion anisotrope et les effets de la polarisation afin d'expliquer quantitativement les résultats expérimentaux. Nous donnons un calcul microscopique de l'albedo cohérent afin de justifier la relation heuristique précédemment établie. Nous prédisons aussi la forme de l'albedo cohérent d'un milieu fractal. Enfin, la validité des différentes approximations utilisées est discutée et quelques développements ultérieurs sont évoqués

Long term outcome after early prehospital thrombolysis: influence on mortality and event free survival

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