13,979 research outputs found
Improving technology transfer through national systems of innovation: climate relevant innovation-system builders (CRIBs)
The Technology Executive Committee (TEC) of the United Nations Framework Convention on Climate Change (UNFCCC) recently convened a workshop seeking to understand how strengthening national systems of innovation (NSIs) might help to foster the transfer of climate technologies to developing countries. This article reviews insights from the literatures on Innovation Studies and Socio-Technical Transitions to demonstrate why this focus on fostering innovation systems has potential to be more transformative as an international policy mechanism for climate technology transfer than anything the UNFCCC has considered to date. Based on insights from empirical research, the article also articulates how the existing architecture of the UNFCCC Technology Mechanism could be usefully extended by supporting the establishment of CRIBs (climate relevant innovation-system builders) in developing countries – key institutions focused on nurturing the climate-relevant innovation systems and building technological capabilities that form the bedrock of transformative, climate-compatible technological change and development
Wound healing angiogenesis the clinical implications of a simple mathematical model
Nonhealing wounds are a major burden for health care systems worldwide. In addition, a patient who suffers from this type of wound usually has a reduced quality of life. While the wound healing process is undoubtedly complex, in this paper we develop a deterministic mathematical model, formulated as a system of partial differential equations, that focusses on an important aspect of successful healing: oxygen supply to the wound bed by a combination of diffusion from the surrounding unwounded tissue and delivery from newly-formed blood vessels. While the model equations can be solved numerically, the emphasis here is on the use of asymptotic methods to establish conditions under which new blood vessel growth can be initiated and wound-bed angiogenesis can progress. These conditions are given in terms of key model parameters including the rate of oxygen supply and its rate of consumption in the wound. We use our model to discuss the clinical use of treatments such as hyperbaric oxygen therapy, wound bed debridement, and revascularisation therapy that have the potential to initiate healing in chronic, stalled wounds
The reduced cost of providing a nationally recognised service for familial hypercholesterolaemia
OBJECTIVE: Familial hypercholesterolaemia (FH) affects 1 in 500 people in the UK population and is associated with premature morbidity and mortality from coronary heart disease. In 2008, National Institute for Health and Care Excellence (NICE) recommended genetic testing of potential FH index cases and cascade testing of their relatives. Commissioners have been slow to respond although there is strong evidence of cost and clinical effectiveness. Our study quantifies the recent reduced cost of providing a FH service using generic atorvastatin and compares NICE costing estimates with three suggested alternative models of care (a specialist-led service, a dual model service where general practitioners (GPs) can access specialist advice, and a GP-led service).METHODS: Revision of existing 3?year costing template provided by NICE for FH services, and prediction of costs for running a programme over 10?years. Costs were modelled for the first population-based FH service in England which covers Southampton, Hampshire, Isle of Wight and Portsmouth (SHIP). Population 1.95 million.RESULTS: With expiry of the Lipitor (Pfizer atorvastatin) patent the cost of providing a 10-year FH service in SHIP reduces by 42.5% (£4.88 million on patent vs £2.80 million off patent). Further cost reductions are possible as a result of the reduced cost of DNA testing, more management in general practice, and lower referral rates to specialists. For instance a dual-care model with GP management of patients supported by specialist advice when required, costs £1.89 million.CONCLUSIONS: The three alternative models of care are now <50% of the cost of the original estimates undertaken by NICE
The Chromospheric Activity and Ages of M Dwarf Stars in Wide Binary Systems
We investigate the relationship between age and chromospheric activity for
139 M dwarf stars in wide binary systems with white dwarf companions. The age
of each system is determined from the cooling age of its white dwarf component.
The current limit for activity-age relations found for M dwarfs in open
clusters is 4 Gyr. Our unique approach to finding ages for M stars allows for
the exploration of this relationship at ages older than 4 Gyr. The general
trend of stars remaining active for a longer time at later spectral type is
confirmed. However, our larger sample and greater age range reveals additional
complexity in assigning age based on activity alone. We find that M dwarfs in
wide binaries older than 4 Gyr depart from the log-linear relation for clusters
and are found to have activity at magnitudes, colors and masses which are
brighter, bluer and more massive than predicted by the cluster relation. In
addition to our activity-age results, we present the measured radial velocities
and complete space motions for 161 white dwarf stars in wide binaries.Comment: 22 pages including 9 figures and 5 tables. Accepted for publication
in The Astronomical Journa
Randomized trial of polychromatic blue-enriched light for circadian phase shifting, melatonin suppression, and alerting responses.
Wavelength comparisons have indicated that circadian phase-shifting and enhancement of subjective and EEG-correlates of alertness have a higher sensitivity to short wavelength visible light. The aim of the current study was to test whether polychromatic light enriched in the blue portion of the spectrum (17,000 K) has increased efficacy for melatonin suppression, circadian phase-shifting, and alertness as compared to an equal photon density exposure to a standard white polychromatic light (4000 K). Twenty healthy participants were studied in a time-free environment for 7 days. The protocol included two baseline days followed by a 26-h constant routine (CR1) to assess initial circadian phase. Following CR1, participants were exposed to a full-field fluorescent light (1 × 10 14 photons/cm 2 /s, 4000 K or 17,000 K, n = 10/condition) for 6.5 h during the biological night. Following an 8 h recovery sleep, a second 30-h CR was performed. Melatonin suppression was assessed from the difference during the light exposure and the corresponding clock time 24 h earlier during CR1. Phase-shifts were calculated from the clock time difference in dim light melatonin onset time (DLMO) between CR1 and CR2. Blue-enriched light caused significantly greater suppression of melatonin than standard light ((mean ± SD) 70.9 ± 19.6% and 42.8 ± 29.1%, respectively, p \u3c 0.05). There was no significant difference in the magnitude of phase delay shifts. Blue-enriched light significantly improved subjective alertness (p \u3c 0.05) but no differences were found for objective alertness. These data contribute to the optimization of the short wavelength-enriched spectra and intensities needed for circadian, neuroendocrine and neurobehavioral regulation
The FHD/ppsilon Epoch of Reionization Power Spectrum Pipeline
Epoch of Reionization data analysis requires unprecedented levels of accuracy
in radio interferometer pipelines. We have developed an imaging power spectrum
analysis to meet these requirements and generate robust 21 cm EoR measurements.
In this work, we build a signal path framework to mathematically describe each
step in the analysis, from data reduction in the FHD package to power spectrum
generation in the ppsilon package. In particular, we focus on the
distinguishing characteristics of FHD/ppsilon: highly accurate
spectral calibration, extensive data verification products, and end-to-end
error propagation. We present our key data analysis products in detail to
facilitate understanding of the prominent systematics in image-based power
spectrum analyses. As a verification to our analysis, we also highlight a
full-pipeline analysis simulation to demonstrate signal preservation and lack
of signal loss. This careful treatment ensures that the
FHD/ppsilon power spectrum pipeline can reduce radio
interferometric data to produce credible 21 cm EoR measurements.Comment: 21 pages, 10 figures, accepted by PAS
Measurements and Predictions on the Elkhart Greek Culvert
This paper describes field measurements and analysis carried out on the Elkhart Creek soil arch culvert structure in British Columbia, Canada. The structure has a span of 13.4 m, a rise of 7.3 m, and a soil cover of 9.6 m. The original structure collapsed during backfilling in October 1987. A new structure of the same design was built in the Fall of 1989, and because of controversy regarding the design thrust value, it was instrumented to measure thrust, moment, and displacements in the arch. Displacements and stresses in the soil were also measured. The measured thrust values were much lower than expected and indicated that significant positive soil-arching occurred. A nonlinear finite element analysis of the soil-structure system was carried out simulating the construction procedures used, and the computed response compared with the measurements. The computed and observed responses were in reasonable agreement in terms of thrust, moment, displacements and soil stresses provided an allowance was made for slip at the bolted connections
Evidence for Accretion in the High-resolution X-ray Spectrum of the T Tauri Star System Hen 3-600
We present high-resolution X-ray spectra of the multiple T Tauri star system
Hen 3-600, obtained with the High Energy Transmission Grating Spectrograph on
the Chandra X-ray Observatory. Two binary components were detected in the
zeroth-order image. Hen 3-600-A, which has a large mid-infrared excess, is a
2-3 times fainter in X-rays than Hen 3-600-B, due to a large flare on B. The
dispersed X-ray spectra of the two primary components overlap spatially;
spectral analysis was performed on the combined system. Analysis of the
individual spectra was limited to regions where the contributions of A and B
can be disentangled. This analysis results in two lines of evidence indicating
that the X-ray emission from Hen 3-600 is derived from accretion processes:
line ratios of O VII indicate that the characteristic density of its
X-ray-emitting plasma is large; a significant component of low-temperature
plasma is present and is stronger in component A. These results are consistent
with results obtained from X-ray gratings spectroscopy of more rapidly
accreting systems. All of the signatures of Hen 3-600 that are potential
diagnostics of accretion activity -- X-ray emission, UV excess, H-alpha
emission, and weak infrared excess -- suggest that its components represent a
transition phase between rapidly accreting, classical T Tauri stars and
non-accreting, weak-lined T Tauri stars.Comment: latex, 27 pages, 12 figures, 6 tables; accepted by Ap
CORE CHARACTERISTICS OF FOUR ARMY PACKAGE POWER REACTORS
A brief discussion of the core charteristics of four uranium fuel, pressurized-water type: Army Package Power Reactors, the SM-1, SM-1A, PM-2A, and SW-2, is presented. The characteristics discussed are cell geometry, fuel plates, core geometry, flux distributions, core loading, core burnout, and control reds. Tables and illustrations are included. (auth
Spatial Regulation of Membrane Fusion Controlled by Modification of Phosphoinositides
Membrane fusion plays a central role in many cell processes from vesicular
transport to nuclear envelope reconstitution at mitosis but the mechanisms that
underlie fusion of natural membranes are not well understood. Studies with
synthetic membranes and theoretical considerations indicate that accumulation of
lipids characterised by negative curvature such as diacylglycerol (DAG)
facilitate fusion. However, the specific role of lipids in membrane fusion of
natural membranes is not well established. Nuclear envelope (NE) assembly was
used as a model for membrane fusion. A natural membrane population highly
enriched in the enzyme and substrate needed to produce DAG has been isolated and
is required for fusions leading to nuclear envelope formation, although it
contributes only a small amount of the membrane eventually incorporated into the
NE. It was postulated to initiate and regulate membrane fusion. Here we use a
multidisciplinary approach including subcellular membrane purification,
fluorescence spectroscopy and Förster resonance energy transfer
(FRET)/two-photon fluorescence lifetime imaging microscopy (FLIM) to demonstrate
that initiation of vesicle fusion arises from two unique sites where these
vesicles bind to chromatin. Fusion is subsequently propagated to the endoplasmic
reticulum-derived membranes that make up the bulk of the NE to ultimately
enclose the chromatin. We show how initiation of multiple vesicle fusions can be
controlled by localised production of DAG and propagated bidirectionally.
Phospholipase C (PLCγ), GTP hydrolysis and
(phosphatidylinsositol-(4,5)-bisphosphate (PtdIns(4,5)P2) are
required for the latter process. We discuss the general implications of membrane
fusion regulation and spatial control utilising such a mechanism
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