652 research outputs found
Downstream benefits vs upstream costs of land use change for water-yield and salt-load targets in the Macquarie Catchment, NSW
The net present value (NPV) of downstream economic benefits of changes in water-yield (W) and salt-load (S) of mean annual river flow received by a lower catchment from an upper catchment are described as a 3-dimensional (NPV,W, S) surface, where dNPV/dW > 0 and dNPV/d(S/W) < 0. Upstream changes in land use (i.e. forest clearing or forest establishment, which result in higher or lower water-yields, respectively) are driven by economic consequences for land owners. This paper defines conditions under which costs of strategic upstream land use changes could be exceeded by compensations afforded by downstream benefits from altered water-yields and/or lower salt loads. The paper presents methods, and preliminary calculations for an example river, quantifying the scope for such combinations, and raising the question of institutional designs to achieve mutually beneficial upstream and downstream outcomes. Examples refer to the Macquarie River downstream of Dubbo, NSW, and Little River, an upstream tributary.policy, markets, upstream, downstream, water, salinity, Land Economics/Use,
Sulfatides Partition Disabled-2 in Response to Platelet Activation
Background: Platelets contact each other at the site of vascular injury to stop bleeding. One negative regulator of platelet aggregation is Disabled-2 (Dab2), which is released to the extracellular surface upon platelet activation. Dab2 inhibits platelet aggregation through its phosphotyrosine-binding (PTB) domain by competing with fibrinogen for aIIbb3 integrin receptor binding by an unknown mechanism. Methodology/Principal Findings: Using protein-lipid overlay and liposome-binding assays, we identified that the N-terminal region of Dab2, including its PTB domain (N-PTB), specifically interacts with sulfatides. Moreover, we determined that such interaction is mediated by two conserved basic motifs with a dissociation constant (K d) of 0.6 mM as estimated by surface plasmon resonance (SPR) analysis. In addition, liposome-binding assays combined with mass spectroscopy studies revealed that thrombin, a strong platelet agonist, cleaved N-PTB at a site located between the basic motifs, a region that becomes protected from thrombin cleavage when bound to sulfatides. Sulfatides on the platelet surface interact with coagulation proteins, playing a major role in haemostasis. Our results show that sulfatides recruit N-PTB to the platelet surface, sequestering it from integrin receptor binding during platelet activation. This is a transient recruitment that follows N-PTB internalization by an actin-dependent process. Conclusions/Significance: Our experimental data support a model where two pools of Dab2 co-exist at the platelet surface
High Stability Engine Control (HISTEC) Flight Test Results
The High Stability Engine Control (HISTEC) Program, managed and funded by the NASA Lewis Research Center, is a cooperative effort between NASA and Pratt & Whitney (P&W). The program objective is to develop and flight demonstrate an advanced high stability integrated engine control system that uses real-time, measurement-based estimation of inlet pressure distortion to enhance engine stability. Flight testing was performed using the NASA Advanced Controls Technologies for Integrated Vehicles (ACTIVE) F-15 aircraft at the NASA Dryden Flight Research Center. The flight test configuration, details of the research objectives, and the flight test matrix to achieve those objectives are presented. Flight test results are discussed that show the design approach can accurately estimate distortion and perform real-time control actions for engine accommodation
The Prograde Orbit of Exoplanet TrES-2b
We monitored the Doppler shift of the G0V star TrES-2 throughout a transit of
its giant planet. The anomalous Doppler shift due to stellar rotation (the
Rossiter-McLaughlin effect) is discernible in the data, with a signal-to-noise
ratio of 2.9, even though the star is a slow rotator. By modeling this effect
we find that the planet's trajectory across the face of the star is tilted by
-9 +/- 12 degrees relative to the projected stellar equator. With 98%
confidence, the orbit is prograde.Comment: ApJ, in press [15 pages
Maximum Entropy Reconstruction of the Interstellar Medium: I. Theory
We have developed a technique to map the three-dimensional structure of the
local interstellar medium using a maximum entropy reconstruction technique. A
set of column densities N to stars of known distance can in principle be used
to recover a three-dimensional density field n, since the two quantities are
related by simple geometry through the equation N = C n, where C is a matrix
characterizing the stellar spatial distribution. In practice, however, there is
an infinte number of solutions to this equation. We use a maximum entropy
reconstruction algorithm to find the density field containing the least
information which is consistent with the observations. The solution obtained
with this technique is, in some sense, the model containing the minimum
structure. We apply the algorithm to several simulated data sets to demonstrate
its feasibility and success at recovering ``real'' density contrasts.
This technique can be applied to any set of column densities whose end points
are specified. In a subsequent paper we shall describe the application of this
method to a set of stellar color excesses to derive a map of the dust
distribution, and to soft X-ray absorption columns to hot stars to derive a map
of the total density of the interstellar medium.Comment: 23 pages, 7 fig.; accepted for publication in the Ap.
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Monitoring Motor Fluctuations in Patients With Parkinson’s Disease Using Wearable Sensors
This paper presents the results of a pilot study to
assess the feasibility of using accelerometer data to estimate the
severity of symptoms and motor complications in patients with
Parkinson’s disease. A support vector machine (SVM) classifier
was implemented to estimate the severity of tremor, bradykinesia
and dyskinesia from accelerometer data features. SVM-based
estimates were compared with clinical scores derived via visual inspection
of video recordings taken while patients performed a series
of standardized motor tasks. The analysis of the video recordings
was performed by clinicians trained in the use of scales for the
assessment of the severity of Parkinsonian symptoms and motor
complications. Results derived from the accelerometer time series
were analyzed to assess the effect on the estimation of clinical scores
of the duration of the window utilized to derive segments (to eventually
compute data features) from the accelerometer data, the use
of different SVM kernels and misclassification cost values, and the
use of data features derived from different motor tasks. Results
were also analyzed to assess which combinations of data features
carried enough information to reliably assess the severity of symptoms
andmotor complications.Combinations of data features were
compared taking into consideration the computational cost associated
with estimating each data feature on the nodes of a body
sensor network and the effect of using such data features on the
reliability of SVM-based estimates of the severity of Parkinsonian
symptoms and motor complications.Engineering and Applied Science
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