7,178 research outputs found
Biosecurity: A 21st Century Challenge
Based on a review of key reports and experts' opinions, summarizes the debate over "dual-use" technologies and the various approaches to controlling biosecurity risk. Outlines proposed preventive measures and steps to build response capacity
Mathematical Foundations of Consciousness
We employ the Zermelo-Fraenkel Axioms that characterize sets as mathematical
primitives. The Anti-foundation Axiom plays a significant role in our
development, since among other of its features, its replacement for the Axiom
of Foundation in the Zermelo-Fraenkel Axioms motivates Platonic
interpretations. These interpretations also depend on such allied notions for
sets as pictures, graphs, decorations, labelings and various mappings that we
use. A syntax and semantics of operators acting on sets is developed. Such
features enable construction of a theory of non-well-founded sets that we use
to frame mathematical foundations of consciousness. To do this we introduce a
supplementary axiomatic system that characterizes experience and consciousness
as primitives. The new axioms proceed through characterization of so- called
consciousness operators. The Russell operator plays a central role and is shown
to be one example of a consciousness operator. Neural networks supply striking
examples of non-well-founded graphs the decorations of which generate
associated sets, each with a Platonic aspect. Employing our foundations, we
show how the supervening of consciousness on its neural correlates in the brain
enables the framing of a theory of consciousness by applying appropriate
consciousness operators to the generated sets in question
Commutative Quantum Operator Algebras
A key notion bridging the gap between {\it quantum operator algebras}
\cite{LZ10} and {\it vertex operator algebras} \cite{Bor}\cite{FLM} is the
definition of the commutativity of a pair of quantum operators (see section 2
below). This is not commutativity in any ordinary sense, but it is clearly the
correct generalization to the quantum context. The main purpose of the current
paper is to begin laying the foundations for a complete mathematical theory of
{\it commutative quantum operator algebras.} We give proofs of most of the
relevant results announced in \cite{LZ10}, and we carry out some calculations
with sufficient detail to enable the interested reader to become proficient
with the algebra of commuting quantum operators.Comment: 22 pages, Late
Externally-polluted white dwarfs with dust disks
We report Spitzer Space Telescope photometry of eleven externally-polluted
white dwarfs. Of the nine stars for which we have IRAC photometry, we find that
GD 40, GD 133 and PG 1015+161 each has an infrared excess that can be
understood as arising from a flat, opaque, dusty disk. GD 56 also has an
infrared excess characteristic of circumstellar dust, but a flat-disk model
cannot reproduce the data unless there are grains as warm as 1700 K and perhaps
not even then. Our data support the previous suggestion that the metals in the
atmosphere of GD 40 are the result of accretion of a tidally-disrupted asteroid
with a chondritic composition.Comment: ApJ, in pres
Ensuring an Impartial Jury in the Age of Social Media
The explosive growth of social networking has placed enormous pressure on one of the most fundamental of American institutions—the impartial jury. Through social networking services like Facebook and Twitter, jurors have committed significant and often high-profile acts of misconduct. Just recently, the Arkansas Supreme Court reversed a death sentence because a juror Tweeted about the case during deliberations. In light of the significant risks to a fair trial that arise when jurors communicate through social media during trial, judges must be vigilant in monitoring for potential outside influences and in deterring misconduct.
In this Article, we present informal survey data from actual jurors on their use of social networking during trial. We discuss the rise of web-based social networks like Facebook and Twitter, and the concerns that arise when jurors communicate about a case through social media before returning a verdict. After surveying how courts have responded to jurors’ social media use, we describe the results of the informal survey. The results support a growing consensus in the legal profession that courts should frequently, as a matter of course, instruct jurors not to use social media to communicate about trial. Although others have stressed the importance of jury instructions in this area, we hope that the informal survey data will further the dialogue by providing an important perspective—that of actual jurors
Spitzer IRAC Observations of White Dwarfs. I. Warm Dust at Metal-Rich Degenerates
This paper presents the results of a Spitzer IRAC 3-8 micron photometric
search for warm dust orbiting 17 nearby, metal-rich white dwarfs, 15 of which
apparently have hydrogen dominated atmospheres (type DAZ). G166-58, G29-38, and
GD 362 manifest excess emission in their IRAC fluxes and the latter two are
known to harbor dust grains warm enough to radiate detectable emission at
near-infrared wavelengths as short as 2 micron. Their IRAC fluxes display
differences compatible with a relatively larger amount of cooler dust at GD
362. G166-58 is presently unique in that it appears to exhibit excess flux only
at wavelengths longer than about 5 micron. Evidence is presented that this
mid-infrared emission is most likely associated with the white dwarf,
indicating that G166-58 bears circumstellar dust no warmer than T~400 K. The
remaining 14 targets reveal no reliable mid-infrared excess, indicating the
majority of DAZ stars do not have warm debris disks sufficiently opaque to be
detected by IRAC.Comment: Accepted to ApJ, 10 figures, 6 table
- …