9,606 research outputs found
Pipes and Connections
This document describes the low-level Pipe and ConnectionManager objects of the Mesh-
Router system. The overall MeshRouter framework provides a general scheme for interest-
limited communications among a number of client processes. This generality is achieved by
a carefully factorized, object-oriented software implementation. Within this framework, the
Pipe and ConnectionManager (base) classes dened in this note specify the interfaces for i) ac-
tual `bits on the wire' communications and ii) dynamic client insertions during overall system
execution. Two specic implementations of the Pipe class are described in detail: a `Memo-
ryPipe' linking objects instanced on a single processor and a more general 'rtisPipe' providing
inter-processor communications built entirely from the standard RTI-s library used in current
JSAF applications. Initialization procedures within the overall MeshRouter system are dis-
cussed, with particular attention given to dynamic management of inter-processor connections.
Prototype RTI-s router processes are discussed, and simple extensions of the standard system
conguration data les are presented
Does nitrate deposition following astrophysical ionizing radiation events pose an additional threat to amphibians?
It is known that amphibians are especially susceptible to the combination of
heightened UVB radiation and increased nitrate concentrations. Various
astrophysical events have been suggested as sources of ionizing radiation that
could pose a threat to life on Earth, through destruction of the ozone layer
and subsequent increase in UVB, followed by deposition of nitrate. In this
study, we investigate whether the nitrate deposition following an ionizing
event is sufficiently large to cause an additional stress beyond that of the
heightened UVB previously considered. We have converted predicted nitrate
depositions to concentration values, utilizing data from the New York State
Department of Environmental Conservation Acid Rain Monitoring Network web site.
Our results show that the increase in nitrate concentration in bodies of water
following the most intense ionization event likely in the last billion years
would not be sufficient to cause a serious additional stress on amphibian
populations and may actually provide some benefit by acting as fertilizer.Comment: This version is a longer, more detailed draft of an article submitted
to the journal Astrobiolog
Moral Neuroenhancement
In this chapter, we introduce the notion of “moral neuroenhancement,” offering a
novel definition as well as spelling out three conditions under which we expect that
such neuroenhancement would be most likely to be permissible (or even desirable).
Furthermore, we draw a distinction between first-order moral capacities, which we
suggest are less promising targets for neurointervention, and second-order moral
capacities, which we suggest are more promising. We conclude by discussing
concerns that moral neuroenhancement might restrict freedom or otherwise “misfire,”
and argue that these concerns are not as damning as they may seem at first
Space acceleration measurement system triaxial sensor head error budget
The objective of the Space Acceleration Measurement System (SAMS) is to measure and record the microgravity environment for a given experiment aboard the Space Shuttle. To accomplish this, SAMS uses remote triaxial sensor heads (TSH) that can be mounted directly on or near an experiment. The errors of the TSH are reduced by calibrating it before and after each flight. The associated error budget for the calibration procedure is discussed here
Superluminous supernovae: No threat from Eta Carinae
Recently Supernova 2006gy was noted as the most luminous ever recorded, with
a total radiated energy of ~10^44 Joules. It was proposed that the progenitor
may have been a massive evolved star similar to eta Carinae, which resides in
our own galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to
detonate. Although it is too distant to pose a serious threat as a normal
supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst
oriented toward the Earth, eta Carinae is about 30,000 times nearer than
2006gy, and we re-evaluate it as a potential superluminous supernova. We find
that given the large ratio of emission in the optical to the X-ray, atmospheric
effects are negligible. Ionization of the atmosphere and concomitant ozone
depletion are unlikely to be important. Any cosmic ray effects should be spread
out over ~10^4 y, and similarly unlikely to produce any serious perturbation to
the biosphere. We also discuss a new possible effect of supernovae, endocrine
disruption induced by blue light near the peak of the optical spectrum. This is
a possibility for nearby supernovae at distances too large to be considered
"dangerous" for other reasons. However, due to reddening and extinction by the
interstellar medium, eta Carinae is unlikely to trigger such effects to any
significant degree.Comment: 19 pages, 2 figures; Revised version as accepted for publication in
Astrobiolog
Picosecond time-resolved pure-rotational coherent anti-Stokes Raman spectroscopy for N-2 thermometry
This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-34-23-3755. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Peer reviewedPublisher PD
Primordial Nucleosynthesis and the Abundances of Beryllium and Boron
The ability to now make measurements of Be and B as well as put constraints
on \lisix\ abundances in metal-poor stars has led to a detailed reexamination
of Big Bang Nucleosynthesis in the A\groughly6 regime. The nuclear reaction
network has been significantly expanded with many new rates added. It is
demonstrated that although a number of reaction rates are poorly
determined, even with extreme values chosen, the standard homogeneous model is
unable to produce significant yields (Be/H and B/H when
abundances fit) above and the \liseven/\lisix\ ratio always exceeds 500.
We also preliminarily explore inhomogeneous models, such as those inspired by a
first order quark-hadron phase transition, where regions with high
neutron/proton ratios can allow some leakage up to . However models that
fit the abundances still seem to have difficulty in obtaining
significant yields.Comment: Plain TeX, 28 pages, 8 figures (not included, but available from
authors). UMN-TH-1020/9
Seafloor Characterization for Trawlability Using the Simrad ME70 Multibeam Echosounder in the Gulf of Alaska
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