2,660 research outputs found
Identification Of Environmental Variables For Use In Monitoring For The Evaluation Of The Rural Environment Protection Scheme
Teagasc wishes to acknowledge the support of the Environmental RTDI Programme 2000â2006 in financing this research project.End of project reportThe aim of this study was to identify and select quantitative environmental attributes for a monitoring programme that may be integrated into an environmental evaluation of Irelandâs agri-environmental scheme. This was achieved primarily by reviewing a range of agri-environmental indicators and suggesting indicators that would be appropriate for monitoring the REPS. The study conducted a desk review to collate information on current best practice in monitoring for environmental quality. A Project Group (comprising representatives from the Environmental Protection Agency [EPA], Department of Agriculture and Food [DAF], Teagasc, and the project supervisors) advised on the ongoing development of the project. There was a consultation process with national experts, and with a selection of stakeholder organisations with an interest in monitoring the environmental impact of the REPS.Environmental Protection Agenc
In vivo microdialysis reveals age-dependent decrease of brain interstitial fluid tau levels in P301S human tau transgenic mice
Although tau is a cytoplasmic protein, it is also found in brain extracellular fluids, e.g., CSF. Recent findings suggest that aggregated tau can be transferred between cells and extracellular tau aggregates might mediate spread of tau pathology. Despite these data, details of whether tau is normally released into the brain interstitial fluid (ISF), its concentration in ISF in relation to CSF, and whether ISF tau is influenced by its aggregation are unknown. To address these issues, we developed a microdialysis technique to analyze monomeric ISF tau levels within the hippocampus of awake, freely moving mice. We detected tau in ISF of wild-type mice, suggesting that tau is released in the absence of neurodegeneration. ISF tau was significantly higher than CSF tau and their concentrations were not significantly correlated. Using P301S human tau transgenic mice (P301S tg mice), we found that ISF tau is fivefold higher than endogenous murine tau, consistent with its elevated levels of expression. However, following the onset of tau aggregation, monomeric ISF tau decreased markedly. Biochemical analysis demonstrated that soluble tau in brain homogenates decreased along with the deposition of insoluble tau. Tau fibrils injected into the hippocampus decreased ISF tau, suggesting that extracellular tau is in equilibrium with extracellular or intracellular tau aggregates. This technique should facilitate further studies of tau secretion, spread of tau pathology, the effects of different disease states on ISF tau, and the efficacy of experimental treatments
Stochastic Background Search Correlating ALLEGRO with LIGO Engineering Data
We describe the role of correlation measurements between the LIGO
interferometer in Livingston, LA, and the ALLEGRO resonant bar detector in
Baton Rouge, LA, in searches for a stochastic background of gravitational
waves. Such measurements provide a valuable complement to correlations between
interferometers at the two LIGO sites, since they are sensitive in a different,
higher, frequency band. Additionally, the variable orientation of the ALLEGRO
detector provides a means to distinguish gravitational wave correlations from
correlated environmental noise. We describe the analysis underway to set a
limit on the strength of a stochastic background at frequencies near 900 Hz
using ALLEGRO data and data from LIGO's E7 Engineering Run.Comment: 8 pages, 2 encapsulated PostScript figures, uses IOP class files,
submitted to the proceedings of the 7th Gravitational Wave Data Analysis
Workshop (which will be published in Classical and Quantum Gravity
NuSTAR Discovery of a Cyclotron Line in the Be/X-ray Binary RX J0520.5-6932 During Outburst
We present spectral and timing analysis of NuSTAR observations of RX
J0520.56932 in the 3-79 keV band collected during its outburst in January
2014. The target was observed on two epochs and we report the detection of a
cyclotron resonant scattering feature with central energies of keV and keV during the two
observations, respectively, corresponding to a magnetic field of G. The 3-79 keV luminosity of the system during the two epochs
assuming a nominal distance of 50 kpc was and
. Both values are much higher
than the critical luminosity of
above which a radiation dominated shock front may be expected. This adds a new
object to the sparse set of three systems that have a cyclotron line observed
at luminosities in excess of . A broad
( keV) Fe emission line is observed in the spectrum at a
central energy of keV in both epochs. The pulse profile
of the pulsar was observed to be highly asymmetric with a sharply rising and
slowly falling profile of the primary peak. We also observed minor variations
in the cyclotron line energy and width as a function of the rotation phase.% As
in observations of other cyclotron absorption line sources, there is a small
() phase difference between the peak of the cyclotron
energy variation and the peak of the flux variation.Comment: 9 pages, 4 figures, 6 tables. Accepted to Ap
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A Contract-Based Methodology for Aircraft Electric Power System Design
In an aircraft electric power system, one or more supervisory control units actuate a set of electromechanical switches to dynamically distribute power from generators to loads, while satisfying safety, reliability, and real-time performance requirements. To reduce expensive redesign steps, this control problem is generally addressed by minor incremental changes on top of consolidated solutions. A more systematic approach is hindered by a lack of rigorous design methodologies that allow estimating the impact of earlier design decisions on the final implementation. To achieve an optimal implementation that satisfies a set of requirements, we propose a platform-based methodology for electric power system design, which enables independent implementation of system topology (i.e., interconnection among elements) and control protocol by using a compositional approach. In our flow, design space exploration is carried out as a sequence of refinement steps from the initial specification toward a final implementation by mapping higher level behavioral and performance models into a set of either existing or virtual library components at the lower level of abstraction. Specifications are first expressed using the formalisms of linear temporal logic, signal temporal logic, and arithmetic constraints on Boolean variables. To reason about different requirements, we use specialized analysis and synthesis frameworks and formulate assume guarantee contracts at the articulation points in the design flow. We show the effectiveness of our approach on a proof-of-concept electric power system design
NuSTAR discovery of an unusually steady long-term spin-up of the Be binary 2RXP J130159.6-635806
We present spectral and timing analysis of NuSTAR observations of the
accreting X-ray pulsar 2RXP J130159.6-635806. The source was serendipitously
observed during a campaign focused on the gamma-ray binary PSR B1259-63 and was
later targeted for a dedicated observation. The spectrum has a typical shape
for accreting X-ray pulsars, consisting of a simple power law with an
exponential cutoff starting at ~7 keV with a folding energy of E_fold=~18 keV.
There is also an indication of the presence of a 6.4 keV iron line in the
spectrum at the ~3 sigma significance level. NuSTAR measurements of the
pulsation period reveal that the pulsar has undergone a strong and steady
spin-up for the last 20 years. The pulsed fraction is estimated to be ~80%, and
is constant with energy up to 40 keV. The power density spectrum shows a break
towards higher frequencies relative to the current spin period. This, together
with steady persistent luminosity, points to a long-term mass accretion rate
high enough to bring the pulsar out of spin equilibrium.Comment: 13 pages, 7 figures, accepted for publication in The Astrophysical
Journa
Observational Limit on Gravitational Waves from Binary Neutron Stars in the Galaxy
Using optimal matched filtering, we search 25 hours of data from the LIGO
40-meter prototype laser interferometric gravitational-wave detector for
gravitational-wave chirps emitted by coalescing binary systems within our
Galaxy. This is the first test of this filtering technique on real
interferometric data. An upper limit on the rate R of neutron star binary
inspirals in our Galaxy is obtained: with 90% confidence, R< 0.5/hour. Similar
experiments with LIGO interferometers will provide constraints on the
population of tight binary neutron star systems in the Universe.Comment: RevTeX, minor revisions, exactly as published in PRL 83 (1999) p1498,
4 pages, 2 figures include
Plans for the LIGO-TAMA Joint Search for Gravitational Wave Bursts
We describe the plans for a joint search for unmodelled gravitational wave
bursts being carried out by the LIGO and TAMA collaborations using data
collected during February-April 2003. We take a conservative approach to
detection, requiring candidate gravitational wave bursts to be seen in
coincidence by all four interferometers. We focus on some of the complications
of performing this coincidence analysis, in particular the effects of the
different alignments and noise spectra of the interferometers.Comment: Proceedings of the 8th Gravitational Wave Data Analysis Workshop,
Milwaukee, WI, USA. 10 pages, 3 figures, documentclass ``iopart'
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