908 research outputs found
Heat and extension at mid- and lower crustal levels of the Rio Grande rift
The process by which large amounts (50 to 200 percent) of crustal extension are produced was concisely described by W. Hamilton in 1982 and 1983. More recently, England, Sawyer, P. Morgan and others have moved toward quantifying models of lithospheric thinning by incorporating laboratory and theoretical data on rock rheology as a function of composition, temperature, and strain rate. Hamilton's description identifies three main crustal layers, each with a distinctive mechanical behavior; brittle fracturing and rotation in the upper crust, discontinuous ductile flow in the middle crust and laminar ductile flow in the lower crust. The temperature and composition dependent brittle-ductile transition essentially defines the diffuse boundary between upper and middle crust. It was concluded that the heat responsible for the highly ductile nature of the lower crust and the lensoidal and magma body structures at mid-crustal depths in the rift was infused into the crust by relatively modest ( 10 percent by mass) magmatic upwelling (feeder dikes) from Moho levels. Seismic velocity-versus-depth data, supported by gravity modeling and the fact that volumes of rift related volcanics are relatively modest ( 6000 cubic km) for the Rio Grande system, all imply velocities and densities too small to be consistent with a massive, composite, mafic intrusion in the lower crust
An Alternative Interpretation of Statistical Mechanics
In this paper I propose an interpretation of classical statistical mechanics that centers on taking seriously the idea that probability measures represent complete states of statistical mechanical systems. I show how this leads naturally to the idea that the stochasticity of statistical mechanics is associated directly with the observables of the theory rather than with the microstates (as traditional accounts would have it). The usual assumption that microstates are representationally significant in the theory is therefore dispensable, a consequence which suggests interesting possibilities for developing non-equilibrium statistical mechanics and investigating inter-theoretic answers to the foundational questions of statistical mechanics
T and CPT Symmetries in Entangled Neutral Meson Systems
Genuine tests of an asymmetry under T and/or CPT transformations imply the
interchange between in-states and out-states. I explain a methodology to
perform model-indepedent separate measurements of the three CP, T and CPT
symmetry violations for transitions involving the decay of the neutral meson
systems in B- and {\Phi}-factories. It makes use of the quantum-mechanical
entanglement only, for which the individual state of each neutral meson is not
defined before the decay of its orthogonal partner. The final proof of the
independence of the three asymmetries is that no other theoretical ingredient
is involved and that the event sample corresponding to each case is different
from the other two. The experimental analysis for the measurements of these
three asymmetries as function of the time interval {\Delta}t > 0 between the
first and second decays is discussed, as well as the significance of the
expected results. In particular, one may advance a first observation of true,
direct, evidence of Time-Reserval-Violation in B-factories by many standard
deviations from zero, without any reference to, and independent of,
CP-Violation. In some quantum gravity framework the CPT-transformation is
ill-defined, so there is a resulting loss of particle-antiparticle identity.
This mechanism induces a breaking of the EPR correlation in the entanglement
imposed by Bose statistics to the neutral meson system, the so-called
{\omega}-effect. I present results and prospects for the {\omega}-parameter in
the correlated neutral meson-antimeson states.Comment: Proc. DISCRETE 2010, Symposium on Prospects in the Physics of
Discrete Symmetries, December 2010, Rom
Studies in the Sintering Permeability and Pellet Strength of Australian Hematite Ores
Sintering of Fine iron ores is achieved by causing a combustion zone to move progressively through a
suitably prepared porous bed of the ore in which is incorpoated a small quantity of a fuel such as finely crushed coke. The agglomeration of the ore particles takes place by their complete fusion and/or the forma-
tion of a partial slag bond between them. In general
the faster the combustion zone passes through the bed
the faster will be the sintering rate
Shifting patterns of genomic variation in the somatic evolution of papillary thyroid carcinoma
Shows Single Nucleotide Substitutions in the MAPK Pathway. (XLSX 43Â kb
The increasing importance of sustainability for building ownership
Purpose — This study seeks to investigate the degree to which energy efficiency is incorporated into office building refurbishment and capital expenditure with the emphasis placed on a cost-benefit analysis from the owner’s perspective. Design/methodology/approach – In order to develop a research framework, a thorough literature review was conducted of three disciplines being construction technology, building refurbishment and property management. The study identifies differences between varying levels of capital expenditure to ensure an existing building is more energy efficient, with the emphasis placed on the cost of implementation and the potential for tenants to acknowledge the increased energy efficiency via higher rents. Findings – Office buildings have been identified as a contributor to global warming during the construction phase, however during the building lifecycle there is a greater contribution to CO2 omissions. Whilst various building designs and construction techniques have evolved to improve energy efficiency, the focus has largely been placed on new buildings where it is easier to incorporate change and innovative approaches. However, the proportion of new buildings constructed each year is relatively small in comparison to existing building stock, which requires regular capital expenditure to maintain and attract new tenants within a competitive marketplace. Practical implications – The increasing importance of energy efficiency affects the office market in a variety of different ways. Originality/value – This paper identifies important links between the environment and the built environment, and the implications for office building owners
Automated and partly automated contact tracing: a systematic review to inform the control of COVID-19
Evidence for the use of automated or partly automated contact-tracing tools to contain severe acute respiratory syndrome
coronavirus 2 is scarce. We did a systematic review of automated or partly automated contact tracing. We searched
PubMed, EMBASE, OVID Global Health, EBSCO Medical COVID Information Portal, Cochrane Library, medRxiv,
bioRxiv, arXiv, and Google Advanced for articles relevant to COVID-19, severe acute respiratory syndrome, Middle East
respiratory syndrome, influenza, or Ebola virus, published from Jan 1, 2000, to April 14, 2020. We also included studies
identified through professional networks up to April 30, 2020. We reviewed all full-text manuscripts. Primary outcomes
were the number or proportion of contacts (or subsequent cases) identified. Secondary outcomes were indicators of
outbreak control, uptake, resource use, cost-effectiveness, and lessons learnt. This study is registered with PROSPERO
(CRD42020179822). Of the 4036 studies identified, 110 full-text studies were reviewed and 15 studies were included in
the final analysis and quality assessment. No empirical evidence of the effectiveness of automated contact tracing
(regarding contacts identified or transmission reduction) was identified. Four of seven included modelling studies that
suggested that controlling COVID-19 requires a high population uptake of automated contact-tracing apps (estimates
from 56% to 95%), typically alongside other control measures. Studies of partly automated contact tracing generally
reported more complete contact identification and follow-up compared with manual systems. Automated contact
tracing could potentially reduce transmission with sufficient population uptake. However, concerns regarding privacy
and equity should be considered. Well designed prospective studies are needed given gaps in evidence of effectiveness,
and to investigate the integration and relative effects of manual and automated systems. Large-scale manual contact
tracing is therefore still key in most contexts
The turn of the valve: representing with material models
Many scientific models are representations. Building on Goodman and Elgin’s notion of representation-as we analyse what this claim involves by providing a general definition of what makes something a scientific model, and formulating a novel account of how they represent. We call the result the DEKI account of representation, which offers a complex kind of representation involving an interplay of, denotation, exemplification, keying up of properties, and imputation. Throughout we focus on material models, and we illustrate our claims with the Phillips-Newlyn machine. In the conclusion we suggest that, mutatis mutandis, the DEKI account can be carried over to other kinds of models, notably fictional and mathematical models
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