1,355 research outputs found
Optical constants of solid methane
Methane is the most abundant simple organic molecule in the outer solar system bodies. In addition to being a gaseous constituent of the atmospheres of the Jovian planets and Titan, it is present in the solid form as a constituent of icy surfaces such as those of Triton and Pluto, and as cloud condensate in the atmospheres of Titan, Uranus, and Neptune. It is expected in the liquid form as a constituent of the ocean of Titan. Cometary ices also contain solid methane. The optical constants for both solid and liquid phases of CH4 for a wide temperature range are needed for radiative transfer calculations, for studies of reflection from surfaces, and for modeling of emission in the far infrared and microwave regions. The astronomically important visual to near infrared measurements of solid methane optical constants are conspicuously absent from the literature. Preliminary results are presented on the optical constants of solid methane for the 0.4 to 2.6 micrometer region. Deposition onto a substrate at 10 K produces glassy (semi-amorphous) material. Annealing this material at approximately 33 K for approximately 1 hour results in a crystalline material as seen by sharper, more structured bands and negligible background extinction due to scattering. The constant k is reported for both the amorphous and the crystalline (annealed) states. Typical values (at absorption maxima) are in the .001 to .0001 range. Below lambda = 1.1 micrometers the bands are too weak to be detected by transmission through the films less than or equal to 215 micrometers in thickness, employed in the studies to date. Using previously measured values of the real part of the refractive index, n, of liquid methane at 110 K, n is computed for solid methane using the Lorentz-Lorenz relationship. Work is in progress to extend the measurements of optical constants n and k for liquid and solid to both shorter and longer wavelengths, eventually providing a complete optical constants database for condensed CH4
Hands-free, precision control for small hovering vehicles - A flying qualities study Final report
Flight simulator determination of human balancing reflex for control of small hovering vehicle
Should all acutely ill children in primary care be tested with point-of-care CRP: A cluster randomised trial
Background: Point-of-care blood C-reactive protein (CRP) testing has diagnostic value in helping clinicians rule out the possibility of serious infection. We investigated whether it should be offered to all acutely ill children in primary care or restricted to those identified as at risk on clinical assessment. Methods: Cluster randomised controlled trial involving acutely ill children presenting to 133 general practitioners (GPs) at 78 GP practices in Belgium. Practices were randomised to undertake point-of-care CRP testing in all children (1730 episodes) or restricted to children identified as at clinical risk (1417 episodes). Clinical risk was assessed by a validated clinical decision rule (presence of one of breathlessness, temperature ℠40 °C, diarrhoea and age 12-30 months, or clinician concern). The main trial outcome was hospital admission with serious infection within 5 days. No specific guidance was given to GPs on interpreting CRP levels but diagnostic performance is reported at 5, 20, 80 and 200 mg/L. Results: Restricting CRP testing to those identified as at clinical risk substantially reduced the number of children tested by 79.9 % (95 % CI, 77.8-82.0 %). There was no significant difference between arms in the number of children with serious infection who were referred to hospital immediately (0.16 % vs. 0.14 %, P = 0.88). Only one child with a CRP < 5 mg/L had an illness requiring admission (a child with viral gastroenteritis admitted for rehydration). However, of the 80 children referred to hospital to rule out serious infection, 24 (30.7 %, 95 % CI, 19.6-45.6 %) had a CRP < 5 mg/L. Conclusions: CRP testing should be restricted to children at higher risk after clinical assessment. A CRP < 5 mg/L rules out serious infection and could be used by GPs to avoid unnecessary hospital referrals
The effects of graded levels of calorie restriction : I. impact of short term calorie and protein restriction on body composition in the C57BL/6 mouse
We acknowledge the BSU staff for their invaluable help with caring for the animals and anonymous referees for their inputs. The work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC) of the UK (Standard grant BB/G009953/1 and China partnering award BB/JO20028/1). The authors declare no competing interests.Peer reviewedPublisher PD
C-reactive protein and neutrophil count laboratory test requests from primary care:what is the demand and would substitution by point of care technology be viable?
Aims: C-reactive protein (CRP) and neutrophil count (NC) are important diagnostic indicators of inflammation. Point-of-care (POC) technologies for these markers are available but rarely used in community settings in the UK. To inform the potential for POC tests, it is necessary to understand the demand for testing. We aimed to describe the frequency of CRP and NC test requests from primary care to central laboratory services, describe variability between practices and assess the relationship between the tests.Methods: We described the number of patients with either or both laboratory tests, and the volume of testing per individual and per practice, in a retrospective cohort of all adults in general practices in Oxfordshire, 2014â2016.Results: 372 017 CRP and 776 581 NC tests in 160 883 and 275 093 patients, respectively, were requested from 69 practices. CRP was tested mainly in combination with NC, while the latter was more often tested alone. The median (IQR) of CRP and NC tests/person tested was 1 (1â2) and 2 (1â3), respectively. The median (IQR) tests/ practice/week was 36 (22â52) and 72 (50â108), and per 1000 persons registered/practice/week was 4 (3â5) and 8 (7â9), respectively. The median (IQR) CRP and NC concentrations were 2.7 (0.9â7.9)mg/dL and 4.1 (3.1â5.5)Ă109/L, respectively.Conclusions: The high demand for CRP and NC testing in the community, and the range of results falling within the reportable range for current POC technologies highlight the opportunity for laboratory testing to be supplemented by POC testing in general practice
Report of the GDR working group on the R-parity violation
This report summarizes the work of the "R-parity violation group" of the
French Research Network (GDR) in Supersymmetry, concerning the physics of
supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron
and LHC and limits on R-parity violating couplings from various processes. The
report includes a discussion of the recent searches at the HERA experiment,
prospects for new experiments, a review of the existing limits, and also
theoretically motivated alternatives to R-parity and a brief discussion on the
implications of R-parity violation on the neutrino masses.Comment: 60 pages, LaTeX, 22 figures, 2 table
Mrk 421, Mrk 501, and 1ES 1426+428 at 100 GeV with the CELESTE Cherenkov Telescope
We have measured the gamma-ray fluxes of the blazars Mrk 421 and Mrk 501 in
the energy range between 50 and 350 GeV (1.2 to 8.3 x 10^25 Hz). The detector,
called CELESTE, used first 40, then 53 heliostats of the former solar facility
"Themis" in the French Pyrenees to collect Cherenkov light generated in
atmospheric particle cascades. The signal from Mrk 421 is often strong. We
compare its flux with previously published multi-wavelength studies and infer
that we are straddling the high energy peak of the spectral energy
distribution. The signal from Mrk 501 in 2000 was weak (3.4 sigma). We obtain
an upper limit on the flux from 1ES 1426+428 of less than half that of the Crab
flux near 100 GeV. The data analysis and understanding of systematic biases
have improved compared to previous work, increasing the detector's sensitivity.Comment: 15 pages, 14 figures, accepted to A&A (July 2006) August 19 --
corrected error in author lis
Inference of proto-neutron star properties in core-collapse supernovae from a gravitational-wave detector network
The next Galactic core-collapse supernova (CCSN) will be a unique opportunity
to study within a fully multi-messenger approach the explosion mechanism
responsible for the formation of neutron stars and stellar-mass black holes.
State-of-the-art numerical simulations of those events reveal the complexity of
the gravitational-wave emission which is highly stochastic. This challenges the
possibility to infer the properties of the compact remnant and of its
progenitor using the information encoded in the waveforms. In this paper we
take further steps in a program we recently initiated to overcome those
difficulties. In particular we show how oscillation modes of the proto-neutron
star, highly visible in the gravitational-wave signal, can be used to
reconstruct the time evolution of their physical properties. Extending our
previous work where only the information from a single detector was used we
here describe a new data-analysis pipeline that coherently combines
gravitational-wave detectors' data and infers the time evolution of a
combination of the mass and radius of the compact remnant. The performance of
the method is estimated employing waveforms from 2D and 3D CCSN simulations
covering a progenitor mass range between 11\, and
40\, and different equations of state for both a network of
up to five second-generation detectors and the proposed third-generation
detectors Einstein Telescope and Cosmic Explorer. Our study shows that it will
be possible to infer PNS properties for CCSN events occurring in the vicinity
of the Milky Way, up to the Large Magellanic Cloud, with the current generation
of gravitational-wave detectors
A global dataset on weather, lake physics, and phytoplankton dynamics
We compiled data from over 30 lakes across the globe to address how storms influence thermal structure
and phytoplankton community dynamics mediated by lake conditions and functional traits. In addition to
(generally) fortnightly phytoplankton samples (mean ± SD temporal coverage across all lakes = 20 ± 13 years),
the dataset includes limnological variables from standard long-term monitoring programs (24 ± 15 years
coverage), daily weather observations (16 ± 10 years coverage) and, when available, high-frequency lake
water temperature and water chemistry profiles (12 ± 7 years coverage). All data have been standardized to
similar formats and include complete metadata. We used the dataset to develop an R-package
(âalgaeClassifyâ), which assigns phytoplankton genus/species information to multiple functional trait groups,
and here we provide a summary of ongoing research using the dataset to investigate: 1) the influence of storm
events on seasonal phytoplankton succession, 2) the impact of storms on lake thermal structure, and 3)
whether lake phytoplankton communities are shaped by long-term patterns in disturbance frequency and
intensity. We give an overview on how to access these data, and we further highlight the opportunities the
dataset provides for asking both basic and applied questions in limnology, ecology, climate change, and lake
management
Impact of extreme weather events frequency and intensity in shaping phytoplankton communities
Lake habitats and communities can often be correlated with general morphometric and geographic
characteristics such as depth, latitude, altitude, or watershed area. Further, communities are typically
correlated with average environmental conditions such as seasonal temperature and nutrient levels. The
frequency and intensity of extreme weather events (rain and wind) are typically not encompassed by average
environmental descriptors, yet, can modify the physical habitats of lakes, significantly influencing
phytoplankton growth and survival. We tested the hypothesis that lakes with a higher frequency and intensity
of extreme weather events have a functionally different phytoplankton assemblage from lakes with a lower
frequency of extreme weather events. We compiled long-term (mean = 20±13 years, range 0.6-44 years)
phytoplankton datasets for 22 lakes across a wide gradient of altitude, latitude, depth, and trophic state. We
classified the phytoplankton genera into morpho-functional groups and C-S-R strategists, and compared
among lake phytoplankton assemblagesâ characteristics across the gradient of wind and rain conditions
experienced by the lakes. We discuss how the frequency of extreme weather events can affect phytoplankton
functional groups, the dominance of differing life history strategies and ultimately community structure. The
frequency and intensity of extreme events is expected to increase with climate change, with the potential to
drive shifts in phytoplankton composition
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