1,671 research outputs found
Remote Predictive Mapping 1. Remote Predictive Mapping (RPM): A Strategy for Geological Mapping of Canadaâs North
Remote Predictive Mapping (RPM) techniques are being developed and refined by the Geological Survey of Canada for mapping Canadaâs North. Remote Predictive Mapping should be considered an integral part of the geological mapping process designed to involve compilation, and re-compilation of data derived from existing geological maps, aerial photographs, satellite imagery, and airborne geophysical data. Predictive geological maps may be iteratively revised and upgraded to publishable geological maps by integrating remotely sensed data with newly acquired field and laboratory data, as RPM techniques are progressively tested and insight evolves. A predictive map, produced without collection of new, field-based data, may also serve as a first-order geologic map in areas where field-based studies cannot be accomplished due to expense of field access or remoteness. As a welcome consequence of adopting RPM into the normal work flow of any mapping or exploration project, there will, by necessity, be greater participation and integration of expertise of field geologists, geophysicists, Geographic Information System (GIS) and remote sensing specialists. Significantly, RPM also encourages geoscience organizations to make full use of all available geoscience data.
This paper outlines a strategy for RPM and provides processing and interpretation examples based on a variety of geoscience data and interpretation techniques to be employed for geologic mapping.
SOMMAIRE
La Commission gĂ©ologique du Canada dĂ©veloppe et raffine des techniques de tĂ©lĂ©cartographique prĂ©dictive (TCP) pour cartographier du Nord canadien. La tĂ©lĂ©cartographie prĂ©dictive doit ĂȘtre perçue comme une composante intĂ©grĂ©e dâun processus de cartographie gĂ©ologique de compilation et de recompilation de donnĂ©es extraites de cartes gĂ©ologiques, de photographies aĂ©riennes, dâimageries satellitaires, et de gĂ©ophysiques aĂ©roportĂ©es existantes. Les cartes gĂ©ologiques prĂ©dictives peu-vent ainsi ĂȘtre rĂ©visĂ©es, mises Ă jour et publiĂ©es selon une approche itĂ©rative intĂ©grant les donnĂ©es de tĂ©lĂ©dĂ©tection avec les donnĂ©es de terrain et de laboratoire nouvellement acquises, au grĂ© de lâĂ©volution et du raffinement des techniques de TCP. Dans les cas de rĂ©gions trop Ă©loignĂ©es, ou parce que les coĂ»ts dâĂ©tablissement de cartes gĂ©ologiques de base rĂ©guliĂšres seraient prohibitifs, la TCP peut aussi ĂȘtre utilisĂ©e pour produire une carte gĂ©ologique de base. DâentrĂ©e de jeu, on rĂ©alise que lâadoption de la TCP dans la routine de production normale de tout projet de cartographie ou dâexploration permettra, en soi, une meilleure prise en compte et une meilleure intĂ©gration des savoirs-faires des gĂ©ologues de terrain, des gĂ©ophysiciens et des spĂ©cialistes de la tĂ©lĂ©dĂ©tection et des systĂšmes dâinformation gĂ©ographique (SIG). Par sa nature mĂȘme, la TCP permet aux organisations gĂ©oscientifiques de faire plein usage de toutes les donnĂ©es gĂ©oscientifiques dont elles disposent.
Le prĂ©sent article dĂ©finit une stratĂ©gie de TCP et dĂ©crit des exemples de traitement et dâinterprĂ©tation dâune variĂ©tĂ© de donnĂ©es gĂ©oscientifiques et de techniques dâinterprĂ©tation utilisables pour la production de cartes gĂ©ologiques
Degradation and forgone removals increase the carbon impact of intact forest loss by 626%
Intact tropical forests, free from substantial anthropogenic influence, store and sequester large amounts of atmospheric carbon but are currently neglected in international climate policy. We show that between 2000 and 2013, direct clearance of intact tropical forest areas accounted for 3.2% of gross carbon emissions from all deforestation across the pantropics. However, full carbon accounting requires the consideration of forgone carbon sequestration, selective logging, edge effects, and defaunation. When these factors were considered, the net carbon impact resulting from intact tropical forest loss between 2000 and 2013 increased by a factor of 6 (626%), from 0.34 (0.37 to 0.21) to 2.12 (2.85 to 1.00) petagrams of carbon (equivalent to approximately 2 years of global land use change emissions). The climate mitigation value of conserving the 549 million ha of tropical forest that remains intact is therefore significant but will soon dwindle if their rate of loss continues to accelerate
Healthcare-associated outbreak of meticillin-resistant Staphylococcus aureus bacteraemia: role of a cryptic variant of an epidemic clone
BACKGROUND
New strains of meticillin-resistant Staphylococcus aureus (MRSA) may be associated with changes in rates of disease or clinical presentation. Conventional typing techniques may not detect new clonal variants that underlie changes in epidemiology or clinical phenotype.
AIM
To investigate the role of clonal variants of MRSA in an outbreak of MRSA bacteraemia at a hospital in England.
METHODS
Bacteraemia isolates of the major UK lineages (EMRSA-15 and -16) from before and after the outbreak were analysed by whole-genome sequencing in the context of epidemiological and clinical data. For comparison, EMRSA-15 and -16 isolates from another hospital in England were sequenced. A clonal variant of EMRSA-16 was identified at the outbreak hospital and a molecular signature test designed to distinguish variant isolates among further EMRSA-16 strains.
FINDINGS
By whole-genome sequencing, EMRSA-16 isolates during the outbreak showed strikingly low genetic diversity (P < 1 Ă 10(-6), Monte Carlo test), compared with EMRSA-15 and EMRSA-16 isolates from before the outbreak or the comparator hospital, demonstrating the emergence of a clonal variant. The variant was indistinguishable from the ancestral strain by conventional typing. This clonal variant accounted for 64/72 (89%) of EMRSA-16 bacteraemia isolates at the outbreak hospital from 2006.
CONCLUSIONS
Evolutionary changes in epidemic MRSA strains not detected by conventional typing may be associated with changes in disease epidemiology. Rapid and affordable technologies for whole-genome sequencing are becoming available with the potential to identify and track the emergence of variants of highly clonal organisms
Charm Contribution to the Structure Function in Diffractive Deep Inelastic Scattering
The charm contribution to the structure functions of diffractive deep
inelastic scattering is considered here within the context of the
Ingelman-Schlein model. Numerical estimations of this contribution are made
from parametrizations of the HERA data. Influence of the Pomeron flux factor is
analized as well as the effect of the shape of the initial parton distribution
employed in the calculations. The obtained results indicate that the charm
contribution to diffractive deep inelastic process might be large enough to be
measured in the HERA experiments.Comment: 16 pages, RevTeX, 6 figures, to be published in Physical Review
Excess Spin and the Dynamics of Antiferromagnetic Ferritin
Temperature-dependent magnetization measurements on a series of synthetic
ferritin proteins containing from 100 to 3000 Fe(III) ions are used to
determine the uncompensated moment of these antiferromagnetic particles. The
results are compared with recent theories of macroscopic quantum coherence
which explicitly include the effect of this excess moment. The scaling of the
excess moment with protein size is consistent with a simple model of finite
size effects and sublattice noncompensation.Comment: 4 pages, 3 Postsript figures, 1 table. Submitted to PR
Challenging Perceptions of Disability through Performance Poetry Methods: The "Seen but Seldom Heard" Project.
This paper considers performance poetry as a method to explore lived experiences
of disability. We discuss how poetic inquiry used within a participatory arts-based
research framework can enable young people to collectively question societyâs
attitudes and actions towards disability. Poetry will be considered as a means to
develop a more accessible and effective arena in which young people with direct
experience of disability can be empowered to develop new skills that enable them
to tell their own stories. Discussion of how this can challenge audiences to critically reflect upon their own perceptions of disability will also be developed
Displaced but not replaced: the impact of e-learning on academic identities in higher education.
Challenges facing universities are leading many to implement institutional strategies to incorporate e-learning rather than leaving its adoption up to enthusiastic individuals. Although there is growing understanding about the impact of e-learning on the student experience, there is less understanding of academicsâ perceptions of e-learning and its impact on their identities. This paper explores the changing nature of academic identities revealed through case study research into the implementation of e-learning at one UK university. By providing insight into the lived experiences of academics in a university in which technology is not only transforming access to knowledge but also influencing the balance of power between academic and student in knowledge production and use, it is suggested that academics may experience a jolt to their âtrajectory of selfâ when engaging with e-learning. The potential for e-learning to prompt loss of teacher presence and displacement as knowledge expert may appear to undermine the ontological security of their academic identity
Thermal correction to the Casimir force, radiative heat transfer, and an experiment
The low-temperature asymptotic expressions for the Casimir interaction
between two real metals described by Leontovich surface impedance are obtained
in the framework of thermal quantum field theory. It is shown that the Casimir
entropy computed using the impedance of infrared optics vanishes in the limit
of zero temperature. By contrast, the Casimir entropy computed using the
impedance of the Drude model attains at zero temperature a positive value which
depends on the parameters of a system, i.e., the Nernst heat theorem is
violated. Thus, the impedance of infrared optics withstands the thermodynamic
test, whereas the impedance of the Drude model does not. We also perform a
phenomenological analysis of the thermal Casimir force and of the radiative
heat transfer through a vacuum gap between real metal plates. The
characterization of a metal by means of the Leontovich impedance of the Drude
model is shown to be inconsistent with experiment at separations of a few
hundred nanometers. A modification of the impedance of infrared optics is
suggested taking into account relaxation processes. The power of radiative heat
transfer predicted from this impedance is several times less than previous
predictions due to different contributions from the transverse electric
evanescent waves. The physical meaning of low frequencies in the Lifshitz
formula is discussed. It is concluded that new measurements of radiative heat
transfer are required to find out the adequate description of a metal in the
theory of electromagnetic fluctuations.Comment: 19 pages, 4 figures. svjour.cls is used, to appear in Eur. Phys. J.
Temperature correction to the Casimir force in cryogenic range and anomalous skin effect
Temperature correction to the Casimir force is considered for real metals at
low temperatures. With the temperature decrease the mean free path for
electrons becomes larger than the field penetration depth. In this condition
description of metals with the impedance of anomalous skin effect is shown to
be more appropriate than with the permittivity. The effect is crucial for the
temperature correction. It is demonstrated that in the zero frequency limit the
reflection coefficients should coincide with those of ideal metal if we demand
the entropy to be zero at T=0. All the other prescriptions discussed in the
literature for the term in the Lifshitz formula give negative entropy. It
is shown that the temperature correction in the region of anomalous skin effect
is not suppressed as it happens in the plasma model. This correction will be
important in the future cryogenic measurements of the Casimir force.Comment: 12 pages, 2 figures, to be published in Phys. Rev.
The influence of gene expression time delays on Gierer-Meinhardt pattern formation systems
There are numerous examples of morphogen gradients controlling long range signalling in developmental and cellular systems. The prospect of two such interacting morphogens instigating long range self-organisation in biological systems via a Turing bifurcation has been explored, postulated, or implicated in the context of numerous developmental processes. However, modelling investigations of cellular systems typically neglect the influence of gene expression on such dynamics, even though transcription and translation are observed to be important in morphogenetic systems. In particular, the influence of gene expression on a large class of Turing bifurcation models, namely those with pure kinetics such as the GiererâMeinhardt system, is unexplored. Our investigations demonstrate that the behaviour of the GiererâMeinhardt model profoundly changes on the inclusion of gene expression dynamics and is sensitive to the sub-cellular details of gene expression. Features such as concentration blow up, morphogen oscillations and radical sensitivities to the duration of gene expression are observed and, at best, severely restrict the possible parameter spaces for feasible biological behaviour. These results also indicate that the behaviour of Turing pattern formation systems on the inclusion of gene expression time delays may provide a means of distinguishing between possible forms of interaction kinetics. Finally, this study also emphasises that sub-cellular and gene expression dynamics should not be simply neglected in models of long range biological pattern formation via morphogens
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