The definitive guide to unsaturated soil— from the world's experts on the subjectThis book builds upon and substantially updates Fredlund and Rahardjo's publication, Soil Mechanics for Unsaturated ...Soils, the current standard in the field of unsaturated soils. It provides readers with more thorough coverage of the state of the art of unsaturated soil behavior and better reflects the manner in which practical unsaturated soil engineering problems are solved. Retaining the fundamental physics of unsaturated soil behavior presented in the earlier book, this new publication places greater emphasis on the importance of the 'soil-water characteristic curve' in solving practical engineering problems, as well as the quantification of thermal and moisture boundary conditions based on the use of weather data. Topics covered include:Theory to Practice of Unsaturated Soil MechanicsNature and Phase Properties of Unsaturated SoilState Variables for Unsaturated SoilsMeasurement and Estimation of State VariablesSoil-Water Characteristic Curves for Unsaturated SoilsGround Surface Moisture Flux Boundary ConditionsTheory of Water Flow through Unsaturated SoilsSolving Saturated/Unsaturated Water Flow ProblemsAir Flow through Unsaturated SoilsHeat Flow Analysis for Unsaturated SoilsShear Strength of Unsaturated SoilsShear Strength Applications in Plastic and Limit EquilibriumStress-Deformation Analysis for Unsaturated SoilsSolving Stress-Deformation Problems with Unsaturated SoilsCompressibility and Pore Pressure ParametersConsolidation and Swelling Processes in Unsaturated SoilsUnsaturated Soil Mechanics in Engineering Practiceis essential reading for geotechnical engineers, civil engineers, and undergraduate- and graduate-level civil engineering students with a focus on soil mechanics.
School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, New South Wales, and Department of Zoology, La Trobe University, Melbourne, Victoria, Australia; Department of Physiology ...and Pharmacology, Karolinska Institutet, Stockholm, Sweden
Repeated, intense use of muscles leads to a decline in performance known as muscle fatigue. Many muscle properties change during fatigue including the action potential, extracellular and intracellular ions, and many intracellular metabolites. A range of mechanisms have been identified that contribute to the decline of performance. The traditional explanation, accumulation of intracellular lactate and hydrogen ions causing impaired function of the contractile proteins, is probably of limited importance in mammals. Alternative explanations that will be considered are the effects of ionic changes on the action potential, failure of SR Ca 2+ release by various mechanisms, and the effects of reactive oxygen species. Many different activities lead to fatigue, and an important challenge is to identify the various mechanisms that contribute under different circumstances. Most of the mechanistic studies of fatigue are on isolated animal tissues, and another major challenge is to use the knowledge generated in these studies to identify the mechanisms of fatigue in intact animals and particularly in human diseases.
Carbon is the fourth-most prevalent element in the Universe and essential for all known life. In the elemental form it is found in multiple allotropes, including graphite, diamond and fullerenes, and ...it has long been predicted that even more structures can exist at pressures greater than those at Earth's core
. Several phases have been predicted to exist in the multi-terapascal regime, which is important for accurate modelling of the interiors of carbon-rich exoplanets
. By compressing solid carbon to 2 terapascals (20 million atmospheres; more than five times the pressure at Earth's core) using ramp-shaped laser pulses and simultaneously measuring nanosecond-duration time-resolved X-ray diffraction, we found that solid carbon retains the diamond structure far beyond its regime of predicted stability. The results confirm predictions that the strength of the tetrahedral molecular orbital bonds in diamond persists under enormous pressure, resulting in large energy barriers that hinder conversion to more-stable high-pressure allotropes
, just as graphite formation from metastable diamond is kinetically hindered at atmospheric pressure. This work nearly doubles the highest pressure at which X-ray diffraction has been recorded on any material.
Density functional theory describes matter at the quantum level, but all popular approximations suffer from systematic errors that arise from the violation of mathematical properties of the exact ...functional. We overcame this fundamental limitation by training a neural network on molecular data and on fictitious systems with fractional charge and spin. The resulting functional, DM21 (DeepMind 21), correctly describes typical examples of artificial charge delocalization and strong correlation and performs better than traditional functionals on thorough benchmarks for main-group atoms and molecules. DM21 accurately models complex systems such as hydrogen chains, charged DNA base pairs, and diradical transition states. More crucially for the field, because our methodology relies on data and constraints, which are continually improving, it represents a viable pathway toward the exact universal functional.
Impaired calcium release during fatigue Allen, D. G; Lamb, G. D; Westerblad, H
Journal of applied physiology (1985),
01/2008, Letnik:
104, Številka:
1
Journal Article
Recenzirano
1 School of Medical Sciences and Bosch Institute, University of Sydney; 2 Department of Zoology, La Trobe University, Melbourne, Victoria, Australia; and 3 Department of Physiology and Pharmacology, ...Karolinska Institutet, Stockholm, Sweden
Impaired calcium release from the sarcoplasmic reticulum (SR) has been identified as a contributor to fatigue in isolated skeletal muscle fibers. The functional importance of this phenomenon can be quantified by the use of agents, such as caffeine, which can increase SR Ca 2+ release during fatigue. A number of possible mechanisms for impaired calcium release have been proposed. These include reduction in the amplitude of the action potential, potentially caused by extracellular K + accumulation, which may reduce voltage sensor activation but is counteracted by a number of mechanisms in intact animals. Reduced effectiveness of SR Ca 2+ channel opening is caused by the fall in intracellular ATP and the rise in Mg 2+ concentrations that occur during fatigue. Reduced Ca 2+ available for release within the SR can occur if inorganic phosphate enters the SR and precipitates with Ca 2+ . Further progress requires the development of methods that can identify impaired SR Ca 2+ release in intact, blood-perfused muscles and that can distinguish between the various mechanisms proposed.
calcium channel; isolated skeletal muscle fibers
Address for reprint requests and other correspondence: D. G. Allen, School of Medical Sciences and Bosch Institute, Univ. of Sydney F13, NSW 2006, Australia (e-mail: davida{at}physiol.usyd.edu.au )
The breast cancer screening programmes in the United Kingdom currently invite women aged 50-70 years for screening mammography every 3 years. Since the time the screening programmes were established, ...there has been debate, at times sharply polarised, over the magnitude of their benefit and harm, and the balance between them. The expected major benefit is reduction in mortality from breast cancer. The major harm is overdiagnosis and its consequences; overdiagnosis refers to the detection of cancers on screening, which would not have become clinically apparent in the woman's lifetime in the absence of screening. Professor Sir Mike Richards, National Cancer Director, England, and Dr Harpal Kumar, Chief Executive Officer of Cancer Research UK, asked Professor Sir Michael Marmot to convene and chair an independent panel to review the evidence on benefits and harms of breast screening in the context of the UK breast screening programmes. The panel, authors of this report, reviewed the extensive literature and heard testimony from experts in the field who were the main contributors to the debate. 85 references
The dentate gyrus (DG) of the mammalian hippocampus is hypothesized to mediate pattern separation--the formation of distinct and orthogonal representations of mnemonic information--and also undergoes ...neurogenesis throughout life. How neurogenesis contributes to hippocampal function is largely unknown. Using adult mice in which hippocampal neurogenesis was ablated, we found specific impairments in spatial discrimination with two behavioral assays: (i) a spatial navigation radial arm maze task and (ii) a spatial, but non-navigable, task in the mouse touch screen. Mice with ablated neurogenesis were impaired when stimuli were presented with little spatial separation, but not when stimuli were more widely separated in space. Thus, newborn neurons may be necessary for normal pattern separation function in the DG of adult mice.
We study Bose-Einstein condensation and the formation of Bose stars in virialized dark matter halos and miniclusters by universal gravitational interactions. We prove that this phenomenon does occur ...and it is described by a kinetic equation. We give an expression for the condensation time. Our results suggest that Bose stars may form kinetically in mainstream dark matter models such as invisible QCD axions and fuzzy dark matter.
X-ray detectors are critical to healthcare diagnostics, cancer therapy and homeland security, with many potential uses limited by system cost and/or detector dimensions. Current X-ray detector ...sensitivities are limited by the bulk X-ray attenuation of the materials and consequently necessitate thick crystals (~1 mm-1 cm), resulting in rigid structures, high operational voltages and high cost. Here we present a disruptive, flexible, low cost, broadband, and high sensitivity direct X-ray transduction technology produced by embedding high atomic number bismuth oxide nanoparticles in an organic bulk heterojunction. These hybrid detectors demonstrate sensitivities of 1712 µC mGy
cm
for "soft" X-rays and ~30 and 58 µC mGy
cm
under 6 and 15 MV "hard" X-rays generated from a medical linear accelerator; strongly competing with the current solid state detectors, all achieved at low bias voltages (-10 V) and low power, enabling detector operation powered by coin cell batteries.
Abstract
The unconventional normal-state properties of the cuprates are often discussed in terms of emergent electronic order that onsets below a putative critical doping of
x
c
≈ 0.19. Charge ...density wave (CDW) correlations represent one such order; however, experimental evidence for such order generally spans a limited range of doping that falls short of the critical value
x
c
, leading to questions regarding its essential relevance. Here, we use X-ray diffraction to demonstrate that CDW correlations in La
2−
x
Sr
x
CuO
4
persist up to a doping of at least
x
= 0.21. The correlations show strong changes through the superconducting transition, but no obvious discontinuity through
x
c
≈ 0.19, despite changes in Fermi surface topology and electronic transport at this doping. These results demonstrate the interaction between CDWs and superconductivity even in overdoped cuprates and prompt a reconsideration of the role of CDW correlations in the high-temperature cuprate phase diagram.
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