683 research outputs found
Photooxidation of the Phenolate Anion is Accelerated at the Water/Air Interface
Molecular photodynamics can be dramatically affected at the water/air interface. Probing such dynamics is challenging, with product formation often probed indirectly through its interaction with interfacial water molecules using time-resolved and phase-sensitive vibrational sum-frequency generation (SFG). Here, the photoproduct formation of the phenolate anion at the water/air interface is probed directly using time-resolved electronic SFG and compared to transient absorption spectra in bulk water. The mechanisms are broadly similar, but 2 to 4 times faster at the surface. An additional decay is observed at the surface which can be assigned to either diffusion of hydrated electrons from the surface into the bulk or due to increased geminate recombination at the surface. These overall results are in stark contrast to phenol, where dynamics were observed to be 104 times faster and for which the hydrated electron was also a photoproduct. Our attempt to probe phenol showed no electron signal at the interface
Macroscopic and Microscopic Entropy of Near-Extremal Spinning Black Holes
A seven parameter family of five-dimensional black hole solutions depending
on mass, two angular momenta, three charges and the asymptotic value of a
scalar field is constructed. The entropy is computed as a function of these
parameters both from the Bekenstein-Hawking formula and from the degeneracies
of the corresponding D-brane states in string theory. The expressions agree at
and to leading order away from extremality.Comment: 7 pages, harvma
The Influence of Skin Temperature on Dermal-Epidermal Adherence: Evidence Compatible with a Highly Viscous Bond
The influence of skin temperature on dermal-epidermal adherence was investigated. The adherence was measured by eliciting suction blisters; blistering time was determined under controlled skin temperature. In the range of skin temperatures investigated (20°–43° C) the adherence decreases continuously with increasing temperature. Adherence is, approximately, an exponential function of temperature; an increase of skin temperature by 10° C decreases blistering time by a factor of about 4. This type of relationship supports the hypothesis that epidermis and dermis are connected by a viscous bond. The strong influence of skin temperature suggests that a high viscosity is involved
Laying the Foundation for Policy: Measuring Local Prevalence for Autism Spectrum Disorder
Claims have been made that families with children living with autism spectrum disorders (ASD) have been migrating to Alberta because of higher funding available for ASD supports compared to other provinces. The legitimacy of these claims, along with many others about the adequacy or inadequacy of funding for supporting persons living with ASD, has not been evaluated because we simply don’t know how many people in Alberta are living with ASD. Typically in Canada, ASD prevalence is reported in national figures, based on international estimates. Canadian prevalence estimates for ASD are needed. With no national surveillance system in place, national estimates are difficult to determine. In addition, such broad measurements are problematic as they may not adequately inform the service delivery needs for specific jurisdictions. A new study shows that 1,711, or 1 in 94, school age children in the Calgary region have an ASD diagnosis. As this number matches what is often reported for the national prevalence of ASD, it suggests that Alberta’s relatively higher ASD funding is not inducing in-migration of families seeking better support. The data also show that the prevalence is higher in elementary-grade children, with a diagnosis in one of every 86 children. In the senior grades, there are significantly fewer students with ASD diagnoses, specifically within the Calgary Board of Education. There is no evident reason for diagnoses to seemingly dematerialize in the older grades. These students could be dropping out or choosing home-schooling in greater numbers. Possibly there has been an increase in prevalence. These prevalence estimates help to inform the demand for special-needs services within the local school system. In addition, there is growing concern that upon graduation there is a “support cliff” resulting from a less systematized, less generous support system available for adults with neurodevelopmental disability. Families that need support for ASD face enough challenges; it is critical for policy-makers to be aware of the extent of the situation in their own jurisdiction so as to develop the right kinds of supports for these families
A novel infrared video surveillance system using deep learning based techniques
This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.This paper presents a new, practical infrared video based surveillance
system, consisting of a resolution-enhanced, automatic target detection/recognition
(ATD/R) system that is widely applicable in civilian and military applications. To
deal with the issue of small numbers of pixel on target in the developed ATD/R
system, as are encountered in long range imagery, a super-resolution method is
employed to increase target signature resolution and optimise the baseline quality
of inputs for object recognition. To tackle the challenge of detecting extremely
low-resolution targets, we train a sophisticated and powerful convolutional neural
network (CNN) based faster-RCNN using long wave infrared imagery datasets
that were prepared and marked in-house. The system was tested under different
weather conditions, using two datasets featuring target types comprising pedestrians
and 6 different types of ground vehicles. The developed ATD/R system can
detect extremely low-resolution targets with superior performance by effectively
addressing the low small number of pixels on target, encountered in long range applications.
A comparison with traditional methods confirms this superiority both
qualitatively and quantitativelyThis work was funded by Thales UK, the Centre of Excellence for
Sensor and Imaging System (CENSIS), and the Scottish Funding Council under the project
“AALART. Thales-Challenge Low-pixel Automatic Target Detection and Recognition (ATD/ATR)”,
ref. CAF-0036. Thanks are also given to the Digital Health and Care Institute (DHI, project
Smartcough-MacMasters), which partially supported Mr. Monge-Alvarez’s contribution, and
to the Royal Society of Edinburgh and National Science Foundation of China for the funding
associated to the project “Flood Detection and Monitoring using Hyperspectral Remote Sensing
from Unmanned Aerial Vehicles”, which partially covered Dr. Casaseca-de-la-Higuera’s,
Dr. Luo’s, and Prof. Wang’s contribution. Dr. Casaseca-de-la-Higuera would also like to acknowledge
the Royal Society of Edinburgh for the funding associated to project “HIVE”
Planck-LFI: Design and Performance of the 4 Kelvin Reference Load Unit
The LFI radiometers use a pseudo-correlation design where the signal from the
sky is continuously compared with a stable reference signal, provided by a
cryogenic reference load system. The reference unit is composed by small
pyramidal horns, one for each radiometer, 22 in total, facing small absorbing
targets, made of a commercial resin ECCOSORB CR (TM), cooled to approximately
4.5 K. Horns and targets are separated by a small gap to allow thermal
decoupling. Target and horn design is optimized for each of the LFI bands,
centered at 70, 44 and 30 GHz. Pyramidal horns are either machined inside the
radiometer 20K module or connected via external electro-formed bended
waveguides. The requirement of high stability of the reference signal imposed a
careful design for the radiometric and thermal properties of the loads.
Materials used for the manufacturing have been characterized for thermal, RF
and mechanical properties. We describe in this paper the design and the
performance of the reference system.Comment: This is an author-created, un-copyedited version of an article
accepted for publication in JINST. IOP Publishing Ltd is not responsible for
any errors or omissions in this version of the manuscript or any version
derived from it. The definitive publisher authenticated version is available
online at [10.1088/1748-0221/4/12/T12006]. 14 pages, 34 figure
Predicting Actions from Static Scenes
International audienceHuman actions naturally co-occur with scenes. In this work we aim to discover action-scene correlation for a large number of scene categories and to use such correlation for action prediction. Towards this goal, we collect a new SUN Action dataset with manual annotations of typical human actions for 397 scenes. We next discover action-scene associations and demonstrate that scene categories can be well identified from their associated actions. Using discovered associations, we address a new task of predicting human actions for images of static scenes. We evaluate prediction of 23 and 38 action classes for images of indoor and outdoor scenes respectively and show promising results. We also propose a new application of geo-localized action prediction and demonstrate ability of our method to automatically answer queries such as "Where is a good place for a picnic?" or "Can I cycle along this path?"
Persistent metabolic changes in HIV-infected patients during the first year of combination antiretroviral therapy
Afdeling Klinische Chemie en Laboratoriumgeneeskunde (AKCL
Large enhancement of deuteron polarization with frequency modulated microwaves
We report a large enhancement of 1.7 in deuteron polarization up to values of
0.6 due to frequency modulation of the polarizing microwaves in a two liters
polarized target using the method of dynamic nuclear polarization. This target
was used during a deep inelastic polarized muon-deuteron scattering experiment
at CERN. Measurements of the electron paramagnetic resonance absorption spectra
show that frequency modulation gives rise to additional microwave absorption in
the spectral wings. Although these results are not understood theoretically,
they may provide a useful testing ground for the deeper understanding of
dynamic nuclear polarization.Comment: 10 pages, including the figures coming in uuencoded compressed tar
files in poltar.uu, which also brings cernart.sty and crna12.sty files neede
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