Search

The author had been focusing on various treatments of time in physics for decades. The author felt that there were major shortcomings in the treatment of time in relativity and even in Newtonian physics. Then the author took a very pragmatic look at how time was actually treated in GPS to achieve a high precision, real world, working, physics system. The author thought that the actual GPS approach might yield a pragmatic time construct for physics. GPS does NOT use special relativity's construct of time--but rather an observer independent construct as detailed below. The author put "Philosophical Time" musings aside and focused solely on finding the right physics construct for time. Finding that proper time was all that physics required, it dawned on the author, quite to his surprise, that proper time also met all the needs of philosophical time. Furthermore, an even deeper physics insight was that "proper time" is simply a measure of a stable physical process' cycles. Hence, "time" as a separate physical entity disappeared to be replaced by physical processes each with its own idiosyncratic length/duration, all of which can be related to each other. These cyclic and noncyclic processes are all driven by known physical forces and energy sources. The properties of time, except for dimensionality, are actually just properties of each individual process that unfolds within 3D space and time is an emergent, human, generalization of process lengths. [ABSTRACT FROM AUTHOR]

Discusses the growing importance of the use of Graphic User Interfaces (GUIs) with microcomputers and online services. Highlights include the development of graphics interfacing with microcomputers; CD-ROM databases; an evaluation of HyperCard as a potential interface to electronic mail and online commercial databases; and future possibilities. (nine references) (LRW)

The education of the deaf and hard of hearing has been the aim and inspiration of many technological discoveries and developments. Since the early work of Alexander Graham Bell, a visionary in special education for the deaf, many relevant innovations have considerably improved the quality of life and the professional opportunities for deaf people of all ages, especially recent advances in cochlear implants. In this article, based on our experience at the Instituto Oral Modelo (IOM) in Buenos Aires, we explain how the digital technology of today has radically changed the education of the deaf and the expectations we may have in the digital era for the next generation of children with auditory deficiencies.

Geodynamic modeling demonstrates various modes of behaviour of the tectonically active continental mantle lithosphere. At continental collision, mantle lithosphere below thickening crust can be accommodated by mixed subduction-like consumption and viscous drip-like instability, depending on the material rheology, temperature, and convergence velocity. Late-stage slab steepening, dual-sided and ablative consumption, and breakoff can occur as the buoyant crust resists subduction. Removal of accreted crust by erosion can modify how even the deepest portions of the mantle lithosphere evolves during contraction. When gravitational forcing rather than plate shortening dominates, mantle lithosphere may be removed through viscous dripping-like instability or delamination. The removal induces crustal heating, modified topography, and deformation, but distinctive styles of these develop depending on whether mantle lithosphere delaminates or drips. With a modified density stratification postulated for the Archean, relatively buoyant mantle lithosphere may undergo an in-situ overturn when triggered by unstable dense eclogite and basal traction. This causes a pulse of rapid crustal heating as hot lowermost lithosphere is brought into contact with the base of the crust. As an interpretive tool, the geodynamic experiments illustrate some of the dynamically feasible modes of behaviour and controlling parameters for the continental mantle lithosphere in ancient to modern tectonic environments. La modelisation geodynamique offre divers modeles de comportement du manteau lithospherique continental tectoniquement actif. Lors de la collision continentale, le manteau lithospherique sous la croflte qui s'eepaissit peut s'adapter par une consommation combineee de type subduction et d'instabilite de type egouttement visqueux, selon la rheologie du materiel, la temperature et la vitesse de convergence. Une accentuation de phase tardive de la pente de la dalle, une consommation ablative--a deux cotes etledeecrochement de la dalle peuvent avoir lieu alors que la croflte flottante resiste a la subduction. Le retrait par erosion de la croflte accretee peut modifier meme la maniere dont les portions les plus profondes du manteau lithospherique eevoluent durant la contraction. Lorsque le fonjage gravitationnel domine plutot que le raccourcissement des plaques, il peut y avoir retrait du manteau lithospherique par une instabilite de type egouttement visqueux ou par delamination. Le retrait cause l'echauffement de la croflte, la modification de la topographie et de la deformation mais les styles distincts de ces effets dependent de la delamination ou de l'egouttement de la lithosphere. En postulant une stratification a densite modifiee pour l'Archeen, la lithosphere dumanteau, relativement legere et flottante, peut subir un renversement in situ s'il est declenche par une eclogite dense et instable et de la traction a la base. Cela cause un echauffement rapide de la croute alors que la chaude lithosphere infeerieure est amenee en contact avec la base de la croflte. Servant d'outils d'interpretation, les essais geeodynamiques illustrent quelques-uns des modes de comportement dynamiquement realisables et des parametres de controle de la lithosphere du manteau continental dans des environnements tectoniques anciens a modernes. [Traduit par la Redaction], Introduction The sub-crustal portion of the lithosphere, the mantle lithosphere, comprises the bulk of the continental lithosphere. Compared to the crust, the structure, composition, and dynamics of the continental mantle [...]

Byline: D. J. Grainger (1), J. Percival (1), M. Chiano (2), T. D. Spector (2) Keywords: Key words:Bone mineral density -- Osteoporosis -- TGF-[beta] Abstract: Osteoporosis is a major public health problem characterized by low bone mineral density (BMD) that presently has no biochemical test useful for its diagnosis. The cytokine TGF-[beta] has been postulated to play a role in controlling bone density by regulating the fine balance between bone matrix deposition by osteoblasts and its resorption by osteoclasts. We explored whether measurement of serum levels of different TGF-[beta] isoforms could be useful as a clinical tool in osteoporosis. We measured the concentration of TGF-[beta]1 antigen using the BDA19 capture sandwich enzyme-linked immunosorbent assay (ELISA), TGF-[beta]2 antigen concentration using a Quantikine sandwich ELISA kit and TGF-[beta]3 antigen concentration using a modified version of the TGF-[beta]1 Quantikine sandwich ELISA kit. Subjects were 41 women with osteoporosis (with nontraumatic vertebral fracture or lumbar spine BMD Z-score &lt -1.5 SD) and a total of 199 control women from different sources. Serum concentrations of TGF-[beta]1 and TGF-[beta]2 were similar in all groups. However, detectable levels of TGF-[beta]3 (&gt 0.2 ng/ml) were found in 35 of 41 patients with osteoporosis (median 7.2 (5.2--8.9) ng/ml) compared with 11 of 36 controls or 24 of 89 healthy women of unknown bone density. Differences among the groups could not be accounted for by age, weight, medications, use of hormone replacement therapy or the presence of osteoarthritis. Using the optimal cut-off of aY=2 ng/ml, the test was able to detect an individual with low spine BMD (Z-score &lt -1.5) with a sensitivity of 84% and a specificity of 53%, with similar results for the femoral neck. The odds ratio for osteoporosis associated with a positive test at this level was 5.93 (95% CI 2.41--11.59), and 4.1 (95% CI 1.66--10.11) using the WHO cut-off of T-score &lt -2.5. Serum TGF-[beta]3 concentration is raised in osteoporotic women and the test appears to have potential as a marker for osteoporosis. The underlying mechanisms and the relationships between TGF-[beta]3 and bone turnover and fractures remain to be explored. Author Affiliation: (1) Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge , GB (2) Twin and Osteoporosis Research Unit, St Thomas' Hospital, London, UK, GB Article note: Received: 4 April 1998 / Accepted: 21 September 1998

To mark the 40th anniversary of punk rock, the British Library ran a free exhibition and a series of associated live spoken-word events in the summer of 2016. Punk was always both outsider (rhetoric, sound, fashion) and insider (the big names of the first-generation UK bands mostly signed to major labels). Using Simon Frith's framework of three overlapping discourses in popular music (folk, pop and art) I argue that the contradictory strands of ideology in and around punk made the British Library the perfect site for this show. [ABSTRACT FROM AUTHOR]

We introduce a set of coupled equations for multi-layer water waves that removes the ill-posedness of the multi-layer Green-Naghdi (MGN) equations in the presence of shear. The new well-posed equations are Hamiltonian and in the absence of imposed background shear, they retain the same travelling wave solutions as MGN. We call the new model the square root depth (√ D) equations from the modified form of their kinetic energy of vertical motion. Our numerical results show how the√ D equations model the effects of multi-layer wave propagation and interaction, with and without shear. [ABSTRACT FROM AUTHOR]

Selection of high-quality sperm is critical to the success of assisted reproductive technologies. Clinical screening for top sperm has long focused on sperm swimming ability when following boundaries or when fully free of constraints. In this work, we demonstrate a sperm selection approach with parallel 2 μm tall confined selection channels that prohibit rotation of the sperm head and require planar swimming. We demonstrate that a planar swimming subpopulation of sperm capable of entering and navigating these channels has DNA integrity superior to the freely-swimming motile or raw sperm populations over a wide range of semen sample qualities. The DNA integrity of the selected sperm was significantly higher than that of the corresponding raw samples for donor samples and clinical patient samples, respectively. In side-by-side testing, this method outperforms current clinical selection methods, density gradient centrifugation and swim-up, as well as sperm selected via general motility. Planar swimming represents a viable sperm selection mechanism with the potential to improve outcomes for couples and offspring. [ABSTRACT FROM AUTHOR]

Abstract: A platform compatible with microtiter plates to parallelize environmental treatments to test the complex impacts of multiple stressors, including parameters relevant to climate change and point source pollutants is developed. This platform leverages (1) the high rate of purely diffusive gas transport in aerogels to produce well‐defined centimeter‐scale gas concentration gradients, (2) spatial light control, and (3) established automated liquid handling. The parallel gaseous, aqueous, and light control provided by the platform is compatible with multiparameter experiments across the life sciences. The platform is applied to measure biological effects in over 700 treatments in a five‐parameter full factorial study with the microalgae Chlamydomonas reinhardtii. Further, the CO2 response of multicellular organisms, Lemna gibba and Artemia salina under surfactant and nanomaterial stress are tested with the platform. [ABSTRACT FROM AUTHOR]

ABSTRACT The spectral distribution of light influences microalgae productivity; however, development of photobioreactors has proceeded largely without regard to spectral optimization. Here, we use monochromatic light to quantify the joint influence of path length, culture density, light intensity, and wavelength on productivity and efficiency in Synechococcus elongatus. The productivity of green light was ∼4× that of red at the highest levels of culture density, depth, and light intensity. This performance is attributed to the combination of increased dilution and penetration of this weakly absorbed wavelength over a larger volume fraction of the reactor. In contrast, red light outperformed other wavelengths in low-density cultures with low light intensities. Low-density cultures also adapted more rapidly to reduce absorption of longer wavelengths, allowing for prolonged cultivation. Taken together, these results indicate that, particularly for artificially lit photobioreactors, wavelength needs to be included as a critical operational parameter to maintain optimal performance. Biotechnol. Bioeng. 2017;114: 1160-1169. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

A novel method for simulating multi-phase flow in porous media is presented. The approach is based on a control volume finite element mixed formulation and new force-balanced finite element pairs. The novelty of the method lies in (i) permitting both continuous and discontinuous description of pressure and saturation between elements; (ii) the use of arbitrarily high-order polynomial representation for pressure and velocity and (iii) the use of high-order flux-limited methods in space and time to avoid introducing non-physical oscillations while achieving high-order accuracy where and when possible. The model is initially validated for two-phase flow. Results are in good agreement with analytically obtained solutions and experimental results. The potential of this method is demonstrated by simulating flow in a realistic geometry composed of highly permeable meandering channels. © 2016 The Authors International Journal for Numerical Methods in Fluids Published by John Wiley & Sons Ltd [ABSTRACT FROM AUTHOR]

Accurately calibrated and characterised x-ray diagnostics are a key requirement in the fielding of experiments on the Orion laser where absolute measurements of x-ray emission are used to underpin the validity of models of emissivity and opacity. Diffraction crystals are used in spectrometers on Orion to record the dispersed spectral features emitted by the laser produced plasma to obtain a measurement of the plasma conditions. The ability to undertake diffraction crystal calibrations supports the successful outcome of these Orion experiments. This paper details the design and commissioning of a system to undertake these calibrations in the energy range 2.0 keV to approximately 8.5 keV. Improvements to the design are detailed which will extend the commissioned range of energies to below 1 keV. [ABSTRACT FROM AUTHOR]

Optimizing bioproduct generation from microalgae is complicated by the myriad of coupled parameters affecting photosynthetic productivity. Quantifying the effect of multiple coupled parameters in full-factorial fashion requires a prohibitively high number of experiments. We present a simple hydrogel-based platform for the rapid, full-factorial mapping of light and nutrient availability on the growth and lipid accumulation of microalgae. We accomplish this without microfabrication using thin sheets of cell-laden hydrogels. By immobilizing the algae in a hydrogel matrix we are able to take full advantage of the continuous spatial chemical gradient produced by a diffusion-based gradient generator while eliminating the need for chambers. We map the effect of light intensities between 0 μmol m−2 s−1 and 130 μmol m−2 s−1 (∼28 W m−2) coupled with ammonium concentrations between 0 mM and 7 mM on Chlamydomonas reinhardtii. Our data set, verified with bulk experiments, clarifies the role of ammonium availability on the photosynthetic productivity Chlamydomonas reinhardtii, demonstrating the dependence of ammonium inhibition on light intensity. Specifically, a sharp optimal growth peak emerges at approximately 2 mM only for light intensities between 80 and 100 μmol m−2 s−1– suggesting that ammonium inhibition is insignificant at lower light intensities. We speculate that this phenomenon is due to the regulation of the high affinity ammonium transport system in Chlamydomonas reinhardtii as well as free ammonia toxicity. The complexity of this photosynthetic biological response highlights the importance of full-factorial data sets as enabled here. [ABSTRACT FROM AUTHOR]

Accurate simulation of multiphase flow in fractured porous media remains a challenge. An important problem is the representation of the discontinuous or near discontinuous behaviour of saturation in real geological formations. In the classical continuum approach, a refined mesh is required at the interface between fracture and porous media to capture the steep gradients in saturation and saturation-dependent transport properties. This dramatically increases the computational load when large numbers of fractures are present in the numerical model. A discontinuous finite element method is reported here to model flow in fractured porous media. The governing multiphase porous media flow equations are solved in the adaptive mesh computational fluid dynamics code IC- FERST on unstructured meshes. The method is based on a mixed control volume - discontinuous finite element formulation. This is combined with the P N+1 DG- P N DG element pair, which has discontinuous (order N+1) representation for velocity and discontinuous (order N) representation for pressure. A number of test cases are used to evaluate the method's ability to model fracture flow. The first is used to verify the performance of the element pair on structured and unstructured meshes of different resolution. Multiphase flow is then modelled in a range of idealised and simple fracture patterns. Solutions with sharp saturation fronts and computational economy in terms of mesh size are illustrated. [ABSTRACT FROM AUTHOR]

Microalgal biofuel is an emerging sustainable energy resource. Photosynthetic growth is heavily dependent on irradiance, therefore photobioreactor design optimization requires comprehensive screening of irradiance variables, such as intensity, time variance and spectral composition. Here we present a microfluidic irradiance assay which leverages liquid crystal display technology to provide multiplexed screening of irradiance conditions on growth. An array of 238 microreactors are operated in parallel with identical chemical environments. The approach is demonstrated by performing three irradiance assays. The first assay evaluates the effect of intensity on growth, quantifying saturating intensity. The second assay quantifies the influence of time-varied intensity and the threshold frequency for growth. Lastly, the coupled influence of red-blue spectral composition and intensity is assessed. Each multiplexed assay is completed within three days. In contrast, completing the same number of experiments using conventional incubation flasks would require several years. Not only does our approach enable more rapid screening, but the short optical path avoids self-shading issues inherent to flask based systems. [ABSTRACT FROM AUTHOR]

We present new approaches to reservoir modeling and flow simulation that dispose of the pillar-grid concept that has persisted since reservoir simulation began. This results in significant improvements to the representation of multiscale geologic heterogeneity and the prediction of flow through that heterogeneity. The research builds on more than 20 years of development of innovative numerical methods in geophysical fluid mechanics, refined and modified to deal with the unique challenges associated with reservoir simulation. Geologic heterogeneities, whether structural, stratigraphic, sedimentologic, or diagenetic in origin, are represented as discrete volumes bounded by surfaces, without reference to a predefined grid. Petrophysical properties are uniform within the geologically defined rock volumes, rather than within grid cells. The resulting model is discretized for flow simulation by use of an unstructured, tetrahedral mesh that honors the architecture of the surfaces. This approach allows heterogeneity over multiple length-scales to be explicitly captured by use of fewer cells than conventional corner-point or unstructured grids. Multiphase flow is simulated by use of a novel mixed finite-element formulation centered on a new family of tetrahedral element types, PN(DG)-PN+1, which has a discontinuous Nth-order polynomial representation for velocity and a continuous (order N +1) representation for pressure. This method exactly represents Darcyforce balances on unstructured meshes and thus accurately calculates pressure, velocity, and saturation fields throughout the domain. Computational costs are reduced through dynamic adaptivemesh optimization and efficient parallelization. Within each rock volume, the mesh coarsens and refines to capture key flow processes during a simulation, and also preserves the surface-based representation of geologic heterogeneity. Computational effort is thus focused on regions of the model where it is most required. After validating the approach against a set of benchmark problems, we demonstrate its capabilities by use of a number of test models that capture aspects of geologic heterogeneity that are difficult or impossible to simulate conventionally, without introducing unacceptably large numbers of cells or highly nonorthogonal grids with associated numerical errors. Our approach preserves key flow features associated with realistic geologic features that are typically lost. The approach may also be used to capture near-wellbore flow features such as coning, changes in surface geometry across multiple stochastic realizations, and, in future applications, geomechanical models with fracture propagation, opening, and closing. [ABSTRACT FROM AUTHOR]

Coalescence of a falling droplet with a sessile droplet on solid surface with various wettabilities is investigated by a combined experimental and numerical study. In the experiments, the droplet diameter, the impact velocity, and the distance between the impacting droplets were controlled. The evolution of surface shape during the coalescence of two droplets on various surfaces is captured using high speed imaging and compared with numerical results. A two-phase volume of fluid method is used to determine the dynamics of droplet coalescence, shape evaluation, and contact line movement. The spreading length of two coalescing droplets along their original centers is also predicted by the model and compared well with the experimental results. The effect of different parameters such as impact velocity, center to center distance, droplet size, and surface wettability on maximum spreading length are studied and compared to the experimental results. Finally, correlations are developed for predicting the maximum spreading length using both experimental and numerical results. [ABSTRACT FROM AUTHOR]

This essay investigates music radio consumption and how it relates to local popular music production. The study focuses on one specialist weekly music programme, Beat Patrol, presented in several formats by Peter Easton at BBC Radio Scotland from 1984 to 2000, and the ways in which a very specific segment of that show's audience (in this case, indie musicians) make sense of that show. Firstly, it offered an independent measurement of the bands' critical success and status in relation to local, regional and national music scenes. The show therefore contributed directly to the acquisition of cultural and social capital for musicians at an early stage of their careers. Secondly, Beat Patrol provided a powerful tool with which bands were able to evaluate both the technical and aesthetic qualities of their recordings in relation to their peers and to artists whose work they admired. The use of this comparative tool suggests that specialist music radio was central to the development of indie musicians' notions of 'good' and 'bad' creative and technical characteristics of their own music. [ABSTRACT FROM AUTHOR]

Abstract: In this paper the synthesis and conductivities of the garnet-related Li ion conductors, Li5Ln3Sb2O12 (Ln=La, Pr, Nd, Sm, Eu), are reported. These phases show high Li ion conductivity, similar to previously reported for the related Li5La3M2O12 (M=Nb, Ta) materials. Neutron diffraction structural studies are also reported for Li5La3Sb2O12 indicating a cubic unit cell, space group Ia-3d, with Li located in two partially occupied sites. [Copyright &y& Elsevier]

Abstract: In this paper we report structural data for the Li ion conducting garnet-related systems, Li6ALa2Nb2O12 (A=Ca, Sr). For both systems, the cell is cubic, space group Ia–3d, with the Li ions located in two partially occupied crystallographic sites, Li1 and Li2. High temperature studies for the A=Sr system show an increased occupancy of the Li2 site at higher temperatures. Both samples have high Li ion conductivity in agreement with previous results, and quenching the samples from elevated temperatures leads to an enhancement in the room temperature conductivity, which may be related to either increased occupancy of the Li2 site or reduced Li ion defect clustering/alkaline earth dopant-defect association in the quenched sample. [Copyright &y& Elsevier]

Abstract: In this paper the synthesis, conductivity, and structure of the garnet-related Li ion conductor, Li5Nd3Sb2O12, are reported. As for the related Li5La3M2O12 (M=Nb, Ta) materials, this phase shows high Li ion conductivity, with a conductivity at 300°C of 9.2×10−3 Scm−1. Structural studies using neutron diffraction indicate a cubic unit cell, space group Ia-3d, with Li located in two partially occupied sites. One of the sites is the traditional garnet structure tetrahedral site, while the other Li site is considerably more distorted. Although the latter is nominally a six coordinate site, a close inspection suggests that the coordination could be described as distorted tetrahedral, with the remaining two bonds being significantly longer (≈2.6Å). [Copyright &y& Elsevier]

This article explains the importance of raising the issue of quitting with everyone who smokes. The problems associated with stopping smoking are explored, the new treatment options described and ways to improve clinical practice suggested. [ABSTRACT FROM AUTHOR]

This article arises from research, funded by the Housing Corporation and Thomas Pocklington Trust, which investigated the housing and support needs and priorities of visually impaired people of working age -a population that has received little public policy attention. It reports on an in-depth study of the circumstances and aspirations of 121 people living in London, which revealed a need for increased opportunities to access information, personal support, employment and housing. The study also discovered strategies that this sample believed would address such need, including better professional collaboration and training, consultation and partnership, and facilitative housing provision. Copyright © 2007 SAGE Publications Ltd. [ABSTRACT FROM AUTHOR]