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Journal ArticleDOI

Phd by thesis

01 Apr 1988-Nature (Nature Publishing Group)-Vol. 332, Iss: 6166, pp 676-676
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

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Citations
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Journal ArticleDOI
TL;DR: In this article, an alternative mode of deformation involving "rotating rigid units" is discussed, which also results in negative Poisson's ratios, and this mechanism may be construc- ted in two dimensions using "rigid polygons" connected together through hinges at their vertices.
Abstract: Auxetic materials exhibit the unexpected feature of becoming fatter when stretched and narrower when compressed, in other words, they exhibit a negative Poisson's ratio. This counter-intuitive behaviour imparts many beneficial effects on the material's macroscopic properties that make auxetics superior to conventional materials in many commercial applications. Recent research suggests that auxetic be-haviour generally results from a cooperative effect between the material's internal structure (geometry setup) and the deformation mechanism it undergoes when submitted to a stress. Auxetic behaviour is also known to be scale-independent, and thus, the same geometry/deformation mechanism may operate at the macro-, micro- and nano- (molecular) level. A considerable amount of research has been focused on the ‘re-entrant honeycomb structure’ which exhibits auxetic behaviour if deformed through hinging at the joints or flexure of the ribs, and it was proposed that this ‘re-entrant’ geometry plays an impor- tant role in generating auxetic behaviour in various forms of materials ranging from nanostructured polymers to foams. This paper discusses an alternative mode of deformation involving ‘rotating rigid units’ which also results in negative Poisson's ratios. In its most ideal form, this mechanism may be construc- ted in two dimensions using ‘rigid polygons’ connected together through hinges at their vertices. On application of uniaxial loads, these ‘rigid polygons’ rotate with respect to each other to form a more open structure hence giving rise to a negative Poisson's ratio. This paper also discusses the role that ‘rotating rigid units’ are thought to have in various classes of materials to give rise to negative Poisson's ratios. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

317 citations


Cites background or methods from "Phd by thesis"

  • ...become a characteristic of auxetic structures), but also this novel mechanism can be used to explain the auxeticity in various classes of materials including foams (microstructured auxetics) and molecular systems such as zeolites or silicates (nanostructured auxetics, see for example, [13, 14, 27, 47]....

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  • ...KGaA, Weinheim Table 1 On-axis Poisson’s ratios in the (001) plane of the SiO2 equivalent of the THO zeolite framework as predicted by various force-field models [27]....

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  • ...1 Rotating rigid units in nanostructured auxetics In a recent study through force-field based molecular modelling experiments, it was shown that various zeolite frameworks exhibit negative Poisson’s ratios, and in the majority of these cases, the auxeticity was the result of deformation mechanisms which can be trivially explained in terms of a ‘rotating squares’ or ‘rotating triangles’ model [26, 27, 43]....

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  • ...3a may be replaced by scalene triangles [27], (see Fig....

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  • ..., the direction of loading) and of the relative rigidity of the squares with respect to the rigidity of the hinges as discussed elsewhere [27] and [45]....

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Journal Article
J. Ahrens, John N. Bahcall, X. Bai, R. C. Bay, T. Becka, K.-H. Becker, D. Berley, Elisa Bernardini, D. Bertrand, D. Z. Besson, E. Blaufuss, D. J. Boersma, S. Böser, C. Bohm, Olga Botner, Adam Bouchta, Othmane Bouhali, T. Burgess, W. Carithers, T. Castermans, J. Cavin, W. Chinowsky, Dmitry Chirkin, B. Collin, Jan Conrad, Jodi Cooley, D. F. Cowen, Anna Davour, C. De Clercq, Tyce DeYoung, Paolo Desiati, R. Ehrlich, R. W. Ellsworth, Paul Evenson, A. R. Fazely, T. Feser, Thomas K. Gaisser, J. S. Gallagher, R. Ganugapati, Heiko Geenen, A. Goldschmidt, J. A. Goodman, R. M. Gunasingha, Allan Hallgren, Francis Halzen, Kael Hanson, R. Hardtke, T. Hauschildt, D. Hays, K. Helbing, M. Hellwig, P. Herquet, G. C. Hill, D. Hubert, B. Hughey, P. O. Hulth, K. Hultqvist, S. Hundertmark, Janet Jacobsen, George Japaridze, A. W. Jones, A. Karle, H. Kawai, M. Kestel, N. Kitamura, R. Koch, L. Köpke, Marek Kowalski, J. I. Lamoureux, H. Leich, I. Liubarsky, James Madsen, H. S. Matis, C. P. McParland, T. Messarius, Peter Mészáros, Y. Minaeva, R.H. Minor, P. Miocinovic, H. Miyamoto, R. Morse, R. Nahnhauer, T. Neunhöffer, P. Niessen, D. R. Nygren, Hakki Ögelman, Ph. Olbrechts, S. J. Patton, R. Paulos, C. Pérez de los Heros, A. C. Pohl, J. Pretz, P. B. Price, Gerald Przybylski, K. Rawlins, Soebur Razzaque, Elisa Resconi, Wolfgang Rhode, M. Ribordy, Stefan Richter, H. G. Sander, K. Schinarakis, S. Schlenstedt, David A. Schneider, R. Schwarz, D. Seckel, A. J. S. Smith, M. Solarz, Glenn Spiczak, Christian Spiering, Michael Stamatikos, T. Stanev, D. Steele, P. Steffen, T. Stezelberger, R. G. Stokstad, K. H. Sulanke, G. W. Sullivan, T. J. Sumner, I. Taboada, S. Tilav, N. van Eijndhoven, Wolfgang Wagner, C. Walck, R.-R Wang, C. H. Wiebusch, C. Wiedemann, R. Wischnewski, Henrike Wissing, K. Woschnagg, S. Yoshida 
TL;DR: In this paper, the authors present the results of a Monte-Carlo study of the sensitivity of the planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV energies.
Abstract: We present the results of a Monte-Carlo study of the sensitivity of the planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV energies. A complete simulation of the detector and data analysis is used to study the detector's capability to search for muon neutrinos from sources such as active galaxies and gamma-ray bursts. We study the effective area and the angular resolution of the detector as a function of muon energy and angle of incidence. We present detailed calculations of the sensitivity of the detector to both diffuse and pointlike neutrino emissions, including an assessment of the sensitivity to neutrinos detected in coincidence with gamma-ray burst observations. After three years of datataking, IceCube will have been able to detect a point source flux of E2*dN/dE = 7*10^-9 cm^-2s^-1GeV at a 5-sigma significance, or, in the absence of a signal, place a 90 percent c.l. limit at a level E2*dN/dE = 2*10^-9 cm^-2s^-1GeV. A diffuse E-2 flux would be detectable at a minimum strength of E2*dN/dE = 1*10^-8 cm^-2s^-1sr^-1GeV. A gamma-ray burst model following the formulation of Waxman and Bahcall would result in a 5-sigma effect after the observation of 200 bursts in coincidence with satellite observations of the gamma-rays.

316 citations


Cites methods from "Phd by thesis"

  • ...Neutrino induced events have been simulated with the program nusim [30]....

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Journal ArticleDOI
M. Aguilar, J. Alcaraz, J.V. Allaby1, Behcet Alpat2  +211 moreInstitutions (27)
TL;DR: In this article, a measurement of the cosmic ray positron fraction in the energy range of 1 −30 GeV was presented, based on data taken by the AMS-01 experiment during its 10-day Space Shuttle flight in June 1998.

314 citations


Cites background from "Phd by thesis"

  • ...In order to gain the highest possible selection efficiency, it is mandatory to apply sophisticated track and vertex finding algorithms which are particularly customized for the converted bremsstrahlung event signature [5]....

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Journal ArticleDOI
TL;DR: It is found that superposition and entanglement are sustained in this living system for at least tens of microseconds, exceeding the durations achieved in the best comparable man-made molecular systems.
Abstract: In artificial systems, quantum superposition and entanglement typically decay rapidly unless cryogenic temperatures are used. Could life have evolved to exploit such delicate phenomena? Certain migratory birds have the ability to sense very subtle variations in Earth's magnetic field. Here we apply quantum information theory and the widely accepted "radical pair" model to analyze recent experimental observations of the avian compass. We find that superposition and entanglement are sustained in this living system for at least tens of microseconds, exceeding the durations achieved in the best comparable man-made molecular systems. This conclusion is starkly at variance with the view that life is too "warm and wet" for such quantum phenomena to endure.

314 citations


Cites background from "Phd by thesis"

  • ...We have also considered a family of variants involving different hyperfine tensors, adding a second nuclear spin (following previous studies where more than one nucleus couples to the system [10, 15, 21, 27]), and replacing the nuclear asymmetry with an anisotropic electron g-factor....

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Journal ArticleDOI
TL;DR: In this article, the covariant and gauge invariant perturbation equations are derived with a method which could also be applied to general $f(R,{R}^{ab}{R}
Abstract: We consider the cosmology where some function $f(G)$ of the Gauss-Bonnet term $G$ is added to the gravitational action to account for the late-time accelerating expansion of the universe. The covariant and gauge invariant perturbation equations are derived with a method which could also be applied to general $f(R,{R}^{ab}{R}_{ab},{R}^{abcd}{R}_{abcd})$ gravitational theories. It is pointed out that, despite their fourth-order character, such $f(G)$ gravity models generally cannot reproduce arbitrary background cosmic evolutions; for example, the standard $\ensuremath{\Lambda}\mathrm{CDM}$ paradigm with ${\ensuremath{\Omega}}_{\mathrm{DE}}=0.76$ cannot be realized in $f(G)$ gravity theories unless $f$ is a true cosmological constant because it imposes exclusionary constraints on the form of $f(G)$. We analyze the perturbation equations and find that, as in the $f(R)$ model, the stability of early-time perturbation growth puts some constraints on the functional form of $f(G)$, in this case ${\ensuremath{\partial}}^{2}f/\ensuremath{\partial}{G}^{2}l0$. Furthermore, the stability of small-scale perturbations also requires that $f$ not deviate significantly from a constant. These analyses are illustrated by numerically propagating the perturbation equations with a specific model reproducing a representative $\ensuremath{\Lambda}\mathrm{CDM}$ cosmic history. Our results show how the $f(G)$ models are highly constrained by cosmological data.

313 citations


Cites methods from "Phd by thesis"

  • ...In what follows, we will only consider scalar modes of perturbations, for which the vorticity ̟ab and magnetic part of Weyl tensor Bab are at most of second order [30, 31] and will be neglected from our first-order analysis....

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  • ...The CGI perturbation equations in general theories of f(G) gravity are derived in this section using the method of 3 + 1 decomposition [28, 29, 30, 31]....

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  • ...Decomposing the Riemann tensor and making use the Einstein equations, we obtain, after linearization, five constraint equations [30, 31]:...

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  • ...The numerical calculation of this work utilizes a modified version of the CAMB code [31, 39]....

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  • ...Moreover, here we are working in the CDM frame (with the ’observer’ comoving with darkmatter particles and so free-falling) in which case we can set Aa = 0 [30, 31] to simplify computations....

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References
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Journal ArticleDOI
TL;DR: A new family of highly fluorescent indicators has been synthesized for biochemical studies of the physiological role of cytosolic free Ca2+ using an 8-coordinate tetracarboxylate chelating site with stilbene chromophores that offer up to 30-fold brighter fluorescence.

21,582 citations


"Phd by thesis" refers background in this paper

  • ...members of this group were produced by Tsien and colleagues [1, 10, 11]....

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  • ...The introduction of Ca 2+ -sensitive fluorescent dyes more than twenty years ago and their permanent improvement [10] enabled investigators to gain unprecedented insights into the mechanisms of cellular signalling....

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ReportDOI
01 Nov 1990
TL;DR: This report will establish methods for performing a domain analysis and describe the products of the domain analysis process to illustrate the application of domain analysis to a representative class of software systems.
Abstract: : Successful Software reuse requires the systematic discovery and exploitation of commonality across related software systems. By examining related software systems and the underlying theory of the class of systems they represent, domain analysis can provide a generic description of the requirements of that class of systems and a set of approaches for their implementation. This report will establish methods for performing a domain analysis and describe the products of the domain analysis process. To illustrate the application of domain analysis to a representative class of software systems, this report will provide a domain analysis of window management system software.

4,420 citations

Journal ArticleDOI
TL;DR: The straw person model (SPM) as mentioned in this paper has been proposed to explain the orientation effects of active galactic nuclei (AGN) and quasars in the line of sight (LOS) images.
Abstract: Because the critical central regions of Active Galactic Nuclei (AGN) and quasars are strongly nonspherical but spatially unresolved, orientation effects have been the source of much confusion. In fact, it now appears that much of the variety in AGN types is just the result of varying orientation relative to the line of sight. We can define an extreme hypothesis,, the straw person model (SPM), in which there are two basic types of AGN: the radio quiets and the radio louds. For each type there is a range in intrinsic luminosity, and the luminosity controls some properties such as the Fanaroff and Riley classes. However, at a given intrinsic luminosity, all other properties such as spectroscopic classification and VLBI component speeds are ascribed to orientation. This model is only a caricature of the unification idea, and is already ruled out on many grounds, but it will be useful for organizing the discussion. I’ll describe what I consider to be convincing evidence that orientation effects are important and widespread. The true situation may be in some sense half way between the SPM and the hypothesis that orientation doesn’t affect classification at aIl. To us optimists, the orienration cup is half full rather than half empty. Although it is too soon to say for sure, the hypothesis that most objects’ classifications would be different if seen from other directions is a tenable one today.

4,005 citations

Journal ArticleDOI
TL;DR: This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants.
Abstract: Cellulose fibrils with widths in the nanometer range are nature-based materials with unique and potentially useful features. Most importantly, these novel nanocelluloses open up the strongly expanding fields of sustainable materials and nanocomposites, as well as medical and life-science devices, to the natural polymer cellulose. The nanodimensions of the structural elements result in a high surface area and hence the powerful interaction of these celluloses with surrounding species, such as water, organic and polymeric compounds, nanoparticles, and living cells. This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants.

3,452 citations

Journal ArticleDOI
TL;DR: The solid electrolyte interphase (SEI) is a protecting layer formed on the negative electrode of Li-ion batteries as a result of electrolyte decomposition, mainly during the first cycle as discussed by the authors.

2,386 citations