1,478 research outputs found
Measurement of the Flux of Ultrahigh Energy Cosmic Rays from Monocular Observations by the High Resolution Fly's Eye Experiment
We have measured the cosmic ray spectrum above 10^17.2 eV using the two air
fluorescence detectors of the High Resolution Fly's Eye observatory operating
in monocular mode. We describe the detector, photo-tube and atmospheric
calibrations, as well as the analysis techniques for the two detectors. We fit
the spectrum to a model consisting of galactic and extra-galactic sources.Comment: 4 pages, 4 figures. Uses 10pt.rtx, amsmath.sty, aps.rtx, revsymb.sty,
revtex4.cl
High-frequency ultrasonic speckle velocimetry in sheared complex fluids
High-frequency ultrasonic pulses at 36 MHz are used to measure velocity
profiles in a complex fluid sheared in the Couette geometry. Our technique is
based on time-domain cross-correlation of ultrasonic speckle signals
backscattered by the moving medium. Post-processing of acoustic data allows us
to record a velocity profile in 0.02--2 s with a spatial resolution of 40
m over 1 mm. After a careful calibration using a Newtonian suspension, the
technique is applied to a sheared lyotropic lamellar phase seeded with
polystyrene spheres of diameter 3--10 m. Time-averaged velocity profiles
reveal the existence of inhomogeneous flows, with both wall slip and shear
bands, in the vicinity of a shear-induced ``layering'' transition. Slow
transient regimes and/or temporal fluctuations can also be resolved and exhibit
complex spatio-temporal flow behaviors with sometimes more than two shear
bands.Comment: 15 pages, 18 figures, submitted to Eur. Phys. J. A
A study of urgent and emergency referrals from NHS Direct within England
Objectives: The presented study aimed to explore referral patterns of National Health Service (NHS) Direct to determine how patients engage with telephone-based healthcare and how telephone-healthcare can manage urgent and emergency care.
Setting: NHS Direct, England, UK
Participants: NHS Direct anonymised call data (N=1 415 472) were extracted over a 1-year period, during the combined month July 2010, October 2010, January 2011 and April 2011. Urgent and emergency calls (N=269 558;
19.0%) were analysed by call factors and patient characteristics alongside symptom classification.
Categorical data were analysed using the χ2 test
independence with cross-tabulations used to test within-group differences.
Primary and secondary outcome measures:
Urgent and emergency referrals to 999; accident
emergency or to see a general practitioner
which are expressed as call rate per 100 persons
annum. Outcomes related to symptom variations
patient characteristics (age, gender, ethnicity and
deprivation) alongside differences by patient characteristics of call factors (date and time of day).
Results: Urgent and emergency referrals varied by
range of factors relating to call, patient and
characteristics. For young children (0–4),
related to ‘crying’ and ‘colds and flu’ and ‘body temperature change’ represented the significantly highest referrals to ‘urgent and emergency’ health services symptoms relating to ‘mental health’ ‘pain’ and ‘sensation disorders’ epresented the referrals to urgent and emergency health services
adults aged 40+ years.
Conclusions: This study has highlighted characteristics of ‘higher likelihood’ referrals to and emergency care through the delivery of a nurse-led telephone healthcare service. This
can help facilitate an understanding of how engage with both in and out of hours care and the of telephone-based healthcare within the care pathway
A Search for Arrival Direction Clustering in the HiRes-I Monocular Data above 10^(19.5) eV
In the past few years, small scale anisotropy has become a primary focus in
the search for source of Ultra-High Energy Cosmic Rays (UHECRs). The Akeno
Giant Air Shower Array (AGASA) has reported the presence of clusters of event
arrival directions in their highest energy data set. The High Resolution Fly's
Eye (HiRes) has accumulated an exposure in one of its monocular eyes at
energies above 10^(19.5) eV comparable to that of AGASA. However, monocular
events observed with an air fluorescence detector are characterized by highly
asymmetric angular resolution. A method is developed for measuring
autocorrelation with asymmetric angular resolution. It is concluded that
HiRes-I observations are consistent with no autocorrelation and that the
sensitivity to clustering of the HiRes-I detector is comparable to that of the
reported AGASA data set. Furthermore, we state with a 90% confidence level that
no more than 13% of the observed HiRes-I events above 10^(19.5) eV could be
sharing common arrival directions. However, because a measure of
autocorrelation makes no assumption of the underlying astrophysical mechanism
that results in clustering phenomena, we cannot claim that the HiRes monocular
analysis and the AGASA analysis are inconsistent beyond a specified confidence
level.Comment: 16 pages, 23 figure
Self-medication with over-the-counter drugs and complementary medications in South Australia's elderly population
A number of surveys have examined use of complementary and alternative
medicines (CAM) in Australia. However, there are limited Australian data on use of CAM and over-the-counter (OTC) medicines in the elderly population. The main aims of this study were to
examine self-medication practices with CAM and OTC medicines among older Australians and
variables associated with their use. Participants seemed to self-medicate in accordance with approved indications,
suggesting they were informed consumers, actively looking after their own health. However, use
of analgesics and aspirin are associated with an increased risk of adverse drug events in the elderly.
Future work should examine how self-medication contributes to polypharmacy and increases the
risk of adverse drug reactions
MAPping out distribution routes for kinesin couriers
In the crowded environment of eukaryotic cells, diffusion is an inefficient distribution mechanism for cellular components. Long-distance active transport is required and is performed by molecular motors including kinesins. Furthermore, in highly polarized, compartmentalized and plastic cells such as neurons, regulatory mechanisms are required to ensure appropriate spatio-temporal delivery of neuronal components. The kinesin machinery has diversified into a large number of kinesin motor proteins as well as adaptor proteins that are associated with subsets of cargo. However, many mechanisms contribute to the correct delivery of these cargos to their target domains. One mechanism is through motor recognition of subdomain-specific microtubule (MT) tracks, sign-posted by different tubulin isoforms, tubulin post-translational modifications (PTMs), tubulin GTPase activity and MT associated proteins (MAPs). With neurons as a model system, a critical review of these regulatory mechanisms is presented here, with particular focus on the emerging contribution of compartmentalised MAPs. Overall, we conclude that – especially for axonal cargo – alterations to the MT track can influence transport, although in vivo, it is likely that multiple track-based effects act synergistically to ensure accurate cargo distribution
How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRR’s Rehabilitation Engineering Research Centers
Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a “total approach to rehabilitation”, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970’s, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program
Mammalian Kinesin-3 Motors Are Dimeric In Vivo and Move by Processive Motility upon Release of Autoinhibition
Kinesin-3 motors drive the transport of synaptic vesicles and other membrane-bound organelles in neuronal cells. In the absence of cargo, kinesin motors are kept inactive to prevent motility and ATP hydrolysis. Current models state that the Kinesin-3 motor KIF1A is monomeric in the inactive state and that activation results from concentration-driven dimerization on the cargo membrane. To test this model, we have examined the activity and dimerization state of KIF1A. Unexpectedly, we found that both native and expressed proteins are dimeric in the inactive state. Thus, KIF1A motors are not activated by cargo-induced dimerization. Rather, we show that KIF1A motors are autoinhibited by two distinct inhibitory mechanisms, suggesting a simple model for activation of dimeric KIF1A motors by cargo binding. Successive truncations result in monomeric and dimeric motors that can undergo one-dimensional diffusion along the microtubule lattice. However, only dimeric motors undergo ATP-dependent processive motility. Thus, KIF1A may be uniquely suited to use both diffuse and processive motility to drive long-distance transport in neuronal cells
Genomic investigations of unexplained acute hepatitis in children
Since its first identification in Scotland, over 1000 cases of unexplained pediatric hepatitis in children have been reported worldwide, including 278 cases in the UK. Here we report investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator subjects, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in liver, blood, plasma or stool from 27/28 cases. We found low levels of Adenovirus (HAdV) and Human Herpesvirus 6B (HHV-6B), in 23/31 and 16/23 respectively of the cases tested. In contrast, AAV2 was infrequently detected at low titre in blood or liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T-cells and B-lineage cells. Proteomic comparison of liver tissue from cases and healthy controls, identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and in severe cases HHV-6B, may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children
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