3,344 research outputs found
Cost effectiveness analysis of different approaches of screening for familial hypercholesterolaemia
Objectives To assess the cost effectiveness of
strategies to screen for and treat familial
hypercholesterolaemia.
Design Cost effectiveness analysis. A care pathway for
each patient was delineated and the associated
probabilities, benefits, and costs were calculated.
Participants Simulated population aged 16Â54 years
in England and Wales.
Interventions Identification and treatment of patients
with familial hypercholesterolaemia by universal
screening, opportunistic screening in primary care,
screening of people admitted to hospital with
premature myocardial infarction, or tracing family
members of affected patients.
Main outcome measure Cost effectiveness calculated
as cost per life year gained (extension of life
expectancy resulting from intervention) including
estimated costs of screening and treatment.
Results Tracing of family members was the most cost
effective strategy (ÂŁ3097 (&5066, $4479) per life year
gained) as 2.6 individuals need to be screened to
identify one case at a cost of ÂŁ133 per case detected. If
the genetic mutation was known within the family
then the cost per life year gained (ÂŁ4914) was only
slightly increased by genetic confirmation of the
diagnosis. Universal population screening was least
cost effective (ÂŁ13 029 per life year gained) as 1365
individuals need to be screened at a cost of ÂŁ9754 per
case detected. For each strategy it was more cost
effective to screen younger people and women.
Targeted strategies were more expensive per person
screened, but the cost per case detected was lower.
Population screening of 16 year olds only was as cost
effective as family tracing (ÂŁ2777 with a clinical
confirmation).
Conclusions Screening family members of people
with familial hypercholesterolaemia is the most cost
effective option for detecting cases across the whole
population
Achieving greater resilience to major events:Organisational learning for safety risk management in complex environments
“Girls Go Green”- A Pre-College Summer Experience Focusing on Energy and the Environment [abstract]
Only abstract of poster available.Track III: Energy InfrastructureResearch has shown that female high school students are concerned about the environment and the impact they will have on it in the future. In the summer of 2008, the Missouri S&T Women's Leadership Institute and the Geological Engineering program co-sponsored a new pilot pre-college summer program for rising junior and senior girls interested in learning more about careers in engineering and science that specifically address these energy conservation and environmental issues. Twenty female high school students (12 seniors and 8 juniors), participated in a week-long residential camp featuring hands-on demonstrations from the Geological Engineering, Electrical Engineering, Materials Engineering, and Nuclear Engineering programs. Several field trips were conducted including one to a hydroelectric dam and another to a renewable energy research site which featured a wind turbine and a photovoltaic array. At the end of the week, students gave presentations about energy- or environment-related topics that they had developed during the week. All 12 seniors have applied for admission to Missouri S&T beginning in Fall 2009, and 8 of the 12 have expressed interest in enrolling in energy and environmental degree programs. The inaugural experience of this program has led to plans for recruiting a larger number of participants in the summer of 2009. The pre-college program may be a small step to addressing two important national goals: 1) attracting more high school students, especially girls, to study engineering and science; and 2) providing formal studies in green issues for future professionals
Topological phases of a dimerized Fermi-Hubbard model for semiconductor nano-lattices
Motivated by recent advances in fabricating artificial lattices in
semiconductors and their promise for quantum simulation of topological
materials, we study the one-dimensional dimerized Fermi-Hubbard model. We show
how the topological phases at half-filling can be characterized by a reduced
Zak phase defined based on the reduced density matrix of each spin subsystem.
Signatures of bulk-boundary correspondence are observed in the triplon
excitation of the bulk and the edge states of uncoupled spins at the
boundaries. At quarter-filling we show that owing to the presence of the
Hubbard interaction the system can undergo a transition to the topological
ground state of the non-interacting Su-Schrieffer-Heeger model with the
application of a moderate-strength external magnetic field. We propose a robust
experimental realization with a chain of dopant atoms in silicon or
gate-defined quantum dots in GaAs where the transition can be probed by
measuring the tunneling current through the many-body state of the chain.Comment: 11 pages, 7 figure
Spin coherent quantum transport of electrons between defects in diamond
The nitrogen-vacancy color center in diamond has rapidly emerged as an
important solid-state system for quantum information processing. While
individual spin registers have been used to implement small-scale diamond
quantum computing, the realization of a large-scale device requires development
of an on-chip quantum bus for transporting information between distant qubits.
Here we propose a method for coherent quantum transport of an electron and its
spin state between distant NV centers. Transport is achieved by the
implementation of spatial stimulated adiabatic Raman passage through the
optical control of the NV center charge states and the confined conduction
states of a diamond nanostructure. Our models show that for two NV centers in a
diamond nanowire, high fidelity transport can be achieved over distances of
order hundreds of nanometres in timescales of order hundreds of nanoseconds.
Spatial adiabatic passage is therefore a promising option for realizing an
on-chip spin quantum bus
The proposed Caroline ESA M3 mission to a Main Belt Comet
We describe Caroline, a mission proposal submitted to the European Space Agency in 2010 in response to the Cosmic Visions M3 call for medium-sized missions. Caroline would have travelled to a Main Belt Comet (MBC), characterizing the object during a flyby, and capturing dust from its tenuous coma for return to Earth. MBCs are suspected to be transition objects straddling the traditional boundary between volatile–poor rocky asteroids and volatile–rich comets. The weak cometary activity exhibited by these objects indicates the presence of water ice, and may represent the primary type of object that delivered water to the early Earth. The Caroline mission would have employed aerogel as a medium for the capture of dust grains, as successfully used by the NASA Stardust mission to Comet 81P/Wild 2. We describe the proposed mission design, primary elements of the spacecraft, and provide an overview of the science instruments and their measurement goals. Caroline was ultimately not selected by the European Space Agency during the M3 call; we briefly reflect on the pros and cons of the mission as proposed, and how current and future mission MBC mission proposals such as Castalia could best be approached
RNAseq reveals hydrophobins that are involved in the adaptation of aspergillus nidulans to lignocellulose
Background
Sugarcane is one of the world’s most profitable crops. Waste steam-exploded sugarcane bagasse (SEB) is a cheap, abundant, and renewable lignocellulosic feedstock for the next-generation biofuels. In nature, fungi seldom exist as planktonic cells, similar to those found in the nutrient-rich environment created within an industrial fermenter. Instead, fungi predominantly form biofilms that allow them to thrive in hostile environments.
Results
In turn, we adopted an RNA-sequencing approach to interrogate how the model fungus, Aspergillus nidulans, adapts to SEB, revealing the induction of carbon starvation responses and the lignocellulolytic machinery, in addition to morphological adaptations. Genetic analyses showed the importance of hydrophobins for growth on SEB. The major hydrophobin, RodA, was retained within the fungal biofilm on SEB fibres. The StuA transcription factor that regulates fungal morphology was up-regulated during growth on SEB and controlled hydrophobin gene induction. The absence of the RodA or DewC hydrophobins reduced biofilm formation. The loss of a RodA or a functional StuA reduced the retention of the hydrolytic enzymes within the vicinity of the fungus. Hence, hydrophobins promote biofilm formation on SEB, and may enhance lignocellulose utilisation via promoting a compact substrate-enzyme-fungus structure.
Conclusion
This novel study highlights the importance of hydrophobins to the formation of biofilms and the efficient deconstruction of lignocellulose
The Murmur of the Sleeping Black Hole: Detection of Nuclear Ultraviolet Variability in LINER Galaxies
LINER nuclei, which are present in many nearby galactic bulges, may be the
manifestation of low-rate or low-radiative-efficiency accretion onto
supermassive central black holes. However, it has been unclear whether the
compact UV nuclear sources present in many LINERs are clusters of massive
stars, rather than being directly related to the accretion process. We have
used HST to monitor the UV variability of a sample of 17 galaxies with LINER
nuclei and compact nuclear UV sources. Fifteen of the 17 galaxies were observed
more than once, with two to five epochs per galaxy, spanning up to a year. We
detect significant variability in most of the sample, with peak-to-peak
amplitudes from a few percent to 50%. In most cases, correlated variations are
seen in two independent bands (F250W and F330W). Comparison to previous UV
measurements indicates, for many objects, long-term variations by factors of a
few over decade timescales. Variability is detected in LINERs with and without
detected compact radio cores, in LINERs that have broad H-alpha wings detected
in their optical spectra (``LINER 1's''), and in those that do not (``LINER
2s''). This variability demonstrates the existence of a non-stellar component
in the UV continuum of all types, and sets a lower limit to the luminosity of
this component. We note a trend in the UV color (F250W/F330W) with spectral
type - LINER 1s tend to be bluer than LINER 2s. This trend may indicate a link
between the shape of the nonstellar continuum and the presence or the
visibility of a broad-line region. In one target, the post-starburst galaxy NGC
4736, we detect variability in a previously noted UV source that is offset by
2.5" (60 pc in projection) from the nucleus. This may be the nearest example of
a binary active nucleus, and of the process leading to black hole merging.Comment: accepted to Ap
Developing a high-resolution x-ray imager using electron-multiplying (EM) CCDs
Applications at synchrotron facilities such as macromolecular crystallography and high energy X-ray diffraction require high resolution imaging detectors with high dynamic range and large surface area. Current systems can be split into two main categories: hybrid pixel detectors and scintillator-coupled Charge-Coupled Devices (CCDs). Whilst both have limitations, CCD-based systems (coupled to fibre-optics to increase imaging area) are often used in these applications due to their small pixels and the high resolution. Electron-Multiplication CCDs (EM-CCDs) are able to suppress the readout noise associated with increased readout speed offering a low noise, high speed detector solution. A previous pilot study using a small-area (8 mm × 8 mm) scintillator-coupled EM-CCD found that through high frame-rates, low noise and novel uses of photon-counting, resolution could be improved from over 80 μm to 25 μm at 2 fps. To further improve this detector system, high speed readout electronics can be used alongside a fibre-optic taper and EM-CCD to create a “best of both worlds” solution consisting of the high resolution of a CCD, along with the low noise, high speed (high dynamic range) and large effective area of pixel detectors. This paper details the developments in the study and discusses the latest results and their implication on the system design
- …