14,827 research outputs found
Co-Operation in Agriculture, Marketing and Rural Credit
Bibliography: p. [96]-100.Mode of access: Internet
Expanding the Realm of Microlensing Surveys with Difference Image Photometry
We present a new technique for monitoring microlensing activity even in
highly crowded fields, and use this technique to place limits on low-mass
MACHOs in the haloes of M31 and the Galaxy. Unlike present Galactic
microlensing surveys, we employ a technique in which a large fraction of the
stellar sample is compressed into a single CCD field, rather than spread out in
a way requiring many different telescope pointings. We implement the suggestion
by Crotts (1992) that crowded fields can be monitored by searching for changes
in flux of variable objects by subtracting images of the same field, taken in
time sequence, positionally registered, photometrically normalized, then
subtracted from one another (or a sequence average). The present work tackles
the most difficult part of this task, the adjustment of the point spread
function among images in the sequence so that seeing variations play an
insignificant role in determining the residual after subtraction. The
interesting signal following this process consists of positive and negative
point sources due to variable sources. The measurement of changes in flux
determined in this way we dub "difference image photometry" (also called "pixel
lensing" [Gould 1996]). - The matching of the image point spread function (PSF)
is accomplished by a division of PSFs in Fourier space to produce a convolution
kernel, in a manner explored for other reasons by Phillips & Davis (1995). In
practice, we find the application of this method is difficult in a typical
telescope and wide field imaging camera due to a subtle interplay between the
spatial variation of the PSF associated with the optical design and the
inevitable time variability of the telescope focus. Such effects lead to
complexities...(abstract continues)Comment: Astronomical Journal, in press (accepted 10 Jul 1996), 49 pages,
Latex 4 requires .sty files, 12 figure
Towards practical classical processing for the surface code
The surface code is unarguably the leading quantum error correction code for
2-D nearest neighbor architectures, featuring a high threshold error rate of
approximately 1%, low overhead implementations of the entire Clifford group,
and flexible, arbitrarily long-range logical gates. These highly desirable
features come at the cost of significant classical processing complexity. We
show how to perform the processing associated with an nxn lattice of qubits,
each being manipulated in a realistic, fault-tolerant manner, in O(n^2) average
time per round of error correction. We also describe how to parallelize the
algorithm to achieve O(1) average processing per round, using only constant
computing resources per unit area and local communication. Both of these
complexities are optimal.Comment: 5 pages, 6 figures, published version with some additional tex
Nudges and other moral technologies in the context of power: Assigning and accepting responsibility
Strawson argues that we should understand moral responsibility in terms of our practices of holding responsible and taking responsibility. The former covers what is commonly referred to as backward-looking responsibility , while the latter covers what is commonly referred to as forward-looking responsibility . We consider new technologies and interventions that facilitate assignment of responsibility. Assigning responsibility is best understood as the second- or third-personal analogue of taking responsibility. It establishes forward-looking responsibility. But unlike taking responsibility, it establishes forward-looking responsibility in someone else. When such assignments are accepted, they function in such a way that those to whom responsibility has been assigned face the same obligations and are susceptible to the same reactive attitudes as someone who takes responsibility. One family of interventions interests us in particular: nudges. We contend that many instances of nudging tacitly assign responsibility to nudgees for actions, values, and relationships that they might not otherwise have taken responsibility for. To the extent that nudgees tacitly accept such assignments, they become responsible for upholding norms that would otherwise have fallen under the purview of other actors. While this may be empowering in some cases, it can also function in such a way that it burdens people with more responsibility that they can (reasonably be expected to) manage
Effects of Dietary Sodium Intake on Blood Flow Regulation During Exercise in Salt Resistant Individuals
PURPOSE: Dietary sodium intake guidelines is ≤2,300 mg/day, yet is exceeded by 90% of Americans. This study examined the impact of a high sodium diet on blood flow regulation during exercise. METHODS: Six males (25 ± 2 years) consumed dietary sodium intake guidelines for two weeks, with one week salt-capsule supplemented (HS: 6,900 mg/day of sodium) and the other week placebo-capsule supplemented (LS: 2,300 mg/day of sodium). At the end of each week, peripheral hemodynamic measurements [blood flow (BF), shear rate (SR), and flow mediated dilation (FMD)/SR)] of the brachial and superficial femoral artery were taken during handgrip (HG) and plantar flexion (PF) exercise, respectively. Each exercise workload was 3 minutes and progressed by 8 kilograms until exhaustion. RESULTS: There were no differences between LS and HS in blood pressure (82 ± 4 v 80 ± 5 mmHg; p = 0.3) or heart rate (56 ± 6 v 59 ± 10 bpm; p = 0.4). HG and PF exercise increased BF, SR, and FMD/SR across workload (p \u3c 0.03 for all), but no difference between diets (p \u3e 0.05 for all). CONCLUSION: Despite previous reports that HS impairs resting vascular function, this study revealed that peripheral vascular function and blood flow regulation during exercise is not impacted by a HS diet.https://scholarscompass.vcu.edu/gradposters/1082/thumbnail.jp
SSL: A software specification language
SSL (Software Specification Language) is a new formalism for the definition of specifications for software systems. The language provides a linear format for the representation of the information normally displayed in a two-dimensional module inter-dependency diagram. In comparing SSL to FORTRAN or ALGOL, it is found to be largely complementary to the algorithmic (procedural) languages. SSL is capable of representing explicitly module interconnections and global data flow, information which is deeply imbedded in the algorithmic languages. On the other hand, SSL is not designed to depict the control flow within modules. The SSL level of software design explicitly depicts intermodule data flow as a functional specification
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