2,625 research outputs found
A mutli-technique search for the most primitive CO chondrites
As part of a study to identify the most primitive COs and to look for weakly altered CMs amongst the COs, we have conducted a multi-technique study of 16 Antarctic meteorites that had been classified as primitive COs. For this study, we have determined: (1) the bulk H, C and N abundances and isotopes, (2) bulk O isotopic compositions, (3) bulk modal mineralogies, and (4) for some selected samples the abundances and compositions of their insoluble organic matter (IOM). Two of the 16 meteorites do appear to be CMs – BUC 10943 seems to be a fairly typical CM, while MIL 090073 has probably been heated. Of the COs, DOM 08006 appears to be the most primitive CO identified to date and is quite distinct from the other members of its pairing group. The other COs fall into two groups that are less primitive than DOM 08006 and ALH 77307, the previously most primitive CO. The first group is composed of members of the DOM 08004 pairing group, except DOM 08006. The second group is composed of meteorites belonging to the MIL 03377 and MIL 07099 pairing groups. These two pairing groups should probably be combined. There is a dichotomy in the bulk O isotopes between the primitive (all Antarctic finds) and the more metamorphosed COs (mostly falls). This dichotomy can only partly be explained by the terrestrial weathering experienced by the primitive Antarctic samples. It seems that the more equilibrated samples interacted to a greater extent with 16O-poor material, probably water, than the more primitive meteorites
Faces do not capture special attention in children with autism spectrum disorder: a change blindness study
Two experiments investigated attention of children with autism spectrum disorder (ASD) to faces and objects. In both experiments, children (7- to 15-year-olds) detected the difference between 2 visual scenes. Results in Experiment 1 revealed that typically developing children (n = 16) detected the change in faces faster than in objects, whereas children with ASD (n = 16) were equally fast in detecting changes in faces and objects. These results were replicated in Experiment 2 (n = 16 in children with ASD and 22 in typically developing children), which does not require face recognition skill. Results suggest that children with ASD lack an attentional bias toward others' faces, which could contribute to their atypical social orienting
Gamification of learning deactivates the Default Mode Network
We hypothesised that embedding educational learning in a game would improve learning outcomes, with increased engagement and recruitment of cognitive resources evidenced by increased activation of working memory network (WMN) and deactivation of Default Mode Network (DMN) regions. In an fMRI study, we compared activity during periods of learning in three conditions that were increasingly game-like: Study-only (when periods of learning were followed by an exemplar question together with its correct answer), Self-quizzing (when periods of learning were followed by a multiple choice question in return for a fixed number of points) and Game-based (when, following each period of learning, participants competed with a peer to answer the question for escalating, uncertain rewards). DMN hubs deactivated as conditions became more game-like, alongside greater self-reported engagement and, in the Game-based condition, higher learning scores. These changes did not occur with any detectable increase in WMN activity. Additionally, ventral striatal activation was associated with responding to questions and receiving positive question
feedback. Results support the significance of DMN deactivation for educational learning, and are aligned with recent evidence suggesting DMN and WMN activity may not always be anti-correlated
Orientations of LASCO Halo CMEs and Their Connection to the Flux Rope Structure of Interplanetary CMEs
Coronal mass ejections (CMEs) observed near the Sun via LASCO coronographic
imaging are the most important solar drivers of geomagnetic storms. ICMEs,
their interplanetary, near-Earth counterparts, can be detected in-situ, for
example, by the Wind and ACE spacecraft. An ICME usually exhibits a complex
structure that very often includes a magnetic cloud (MC). They can be commonly
modelled as magnetic flux ropes and there is observational evidence to expect
that the orientation of a halo CME elongation corresponds to the orientation of
the flux rope. In this study, we compare orientations of elongated CME halos
and the corresponding MCs, measured by Wind and ACE spacecraft. We characterize
the MC structures by using the Grad-Shafranov reconstruction technique and
three MC fitting methods to obtain their axis directions. The CME tilt angles
and MC fitted axis angles were compared without taking into account handedness
of the underlying flux rope field and the polarity of its axial field. We
report that for about 64% of CME-MC events, we found a good correspondence
between the orientation angles implying that for the majority of interplanetary
ejecta their orientations do not change significantly (less than 45 deg
rotation) while travelling from the Sun to the near Earth environment
Does gaze direction modulate facial expression processing in children with autism spectrum disorder?
Two experiments investigated whether children with autism spectrum disorder (ASD) integrate relevant communicative signals, such as gaze direction, when decoding a facial expression. In Experiment 1, typically developing children (9–14 years old; n = 14) were faster at detecting a facial expression accompanying a gaze direction with a congruent motivational tendency (i.e., an avoidant facial expression with averted eye gaze) than those with an incongruent motivational tendency. Children with ASD (9–14 years old; n = 14) were not affected by the gaze direction of facial stimuli. This finding was replicated in Experiment 2, which presented only the eye region of the face to typically developing children (n = 10) and children with ASD (n = 10). These results demonstrated that children with ASD do not encode and/or integrate multiple communicative signals based on their affective or motivational tendency
Born to learn: The inspiration, progress, and future of evolved plastic artificial neural networks
Biological plastic neural networks are systems of extraordinary computational
capabilities shaped by evolution, development, and lifetime learning. The
interplay of these elements leads to the emergence of adaptive behavior and
intelligence. Inspired by such intricate natural phenomena, Evolved Plastic
Artificial Neural Networks (EPANNs) use simulated evolution in-silico to breed
plastic neural networks with a large variety of dynamics, architectures, and
plasticity rules: these artificial systems are composed of inputs, outputs, and
plastic components that change in response to experiences in an environment.
These systems may autonomously discover novel adaptive algorithms, and lead to
hypotheses on the emergence of biological adaptation. EPANNs have seen
considerable progress over the last two decades. Current scientific and
technological advances in artificial neural networks are now setting the
conditions for radically new approaches and results. In particular, the
limitations of hand-designed networks could be overcome by more flexible and
innovative solutions. This paper brings together a variety of inspiring ideas
that define the field of EPANNs. The main methods and results are reviewed.
Finally, new opportunities and developments are presented
RAPID : research on automated plankton identification
Author Posting. © Oceanography Society, 2007. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 20, 2 (2007): 172-187.When Victor Hensen deployed the first
true plankton1 net in 1887, he and his
colleagues were attempting to answer
three fundamental questions: What
planktonic organisms are present in
the ocean? How many of each type are
present? How does the plankton’s composition
change over time? Although
answering these questions has remained
a central goal of oceanographers, the
sophisticated tools available to enumerate
planktonic organisms today offer
capabilities that Hensen probably could
never have imagined.This material
is based upon work supported by
the National Science Foundation under
Grants OCE-0325018, OCE-0324937,
OCE-0325167 and OCE-9423471,
and the European Union under grants
Q5CR-2002-71699, MAS3-ct98-0188,
and MAS2-ct92-0015
Recommended from our members
An overview of sea state conditions and air-sea fluxes during RaDyO
Refining radiative-transfer modeling capabilities for light transmission through the sea surface requires a more detailed prescription of the sea surface roughness beyond the probability density function of the sea surface slope field. To meet this need, exciting new measurement methodologies now provide the opportunity to enhance present knowledge of sea surface roughness, especially at the microscale. In this context, two intensive field experiments using R/P Floating Instrument Platform were staged within the Office of Naval Research's Radiance in a Dynamic Ocean (RaDyO) field program in the Santa Barbara Channel and in the central Pacific Ocean south of Hawaii. As part of this program, our team gathered and analyzed a comprehensive suite of sea surface roughness measurements designed to provide optimal coverage of fundamental optical distortion processes associated with the air-sea interface. This contribution describes the ensemble of instrumentation deployed. It provides a detailed documentation of the ambient environmental conditions that prevailed during the RaDyO field experiments. It also highlights exciting new sea surface roughness measurement capabilities that underpin a number of the scientific advances resulting from the RaDyO program. For instance, a new polarimetric imaging camera highlights the complex interplay of wind and surface currents in shaping the roughness of the sea surface that suggests the traditional Cox-Munk framework is not sufficient. In addition, the breaking crest length spectral density derived from visible and infrared imagery is shown to be modulated by the development of the wavefield (wave age) and alignment of wind and surface currents at the intermediate (dominant) scale of wave breaking
Urban naturalistic meadows to promote cultural and regulating ecosystem services
This thesis examined the ecosystem services delivered by a new type of vegetation comprised of grasses and forbs organised in biodiverse naturalistic meadows. The study site was a 500 metres retrofitted linear greenway, the Grey to Green, installed in Sheffield (UK) city centre. A street survey showed users highly appreciated the vegetation and had an improved the perception of the urban environment and thus established the delivery of cultural ecosystem services. By means of a questionnaire and micro-climatic measurements, a thermal sensation scale for Sheffield was defined. In addition to evidence for the role of physiological acclimatisation, a link was found between appreciation of the green space and tolerance to thermal discomfort. The influence of psychological factors on thermal comfort was further investigated using a visual questionnaire. Results highlighted interactions between thermal preference, thermal expectation, landscape appreciation and long-term experience. The microclimatic regulating services of meadows was demonstrated via a yearlong comparative study of surface temperature against that of shaded and exposed turf and concrete. The results
highlighted meadows have a measurable impact on reducing the Urban Heat Island effect; and, at times, more efficiently so than trees. The environmental simulation software Envi-Met was tested against field data and was showed to predict realistically surface temperature. This thesis demonstrated the usefulness of urban meadows in cultural and regulating ecosystem services delivery. They may ease surface heat accumulation, improve perceptual qualities of the urban environment and improve the sensation of thermal comfort. Thus, they contribute to making cities more liveable
Postoperative pain management in children: Guidance from the pain committee of the European Society for Paediatric Anaesthesiology (ESPA Pain Management Ladder Initiative)
The main remit of the European Society for Paediatric Anaesthesiology (ESPA) Pain Committee is to improve the quality of pain management in children. The ESPA Pain Management Ladder is a clinical practice advisory based upon expert consensus to help to ensure a basic standard of perioperative pain management for all children. Further steps are suggested to improve pain management once a basic standard has been achieved. The guidance is grouped by the type of surgical procedure and layered to suggest basic, intermediate, and advanced pain management methods. The committee members are aware that there are marked differences in financial and personal resources in different institutions and countries and also considerable variations in the availability of analgesic drugs across Europe. We recommend that the guidance should be used as a framework to guide best practice
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