2,826 research outputs found
Quantum fingerprinting
Classical fingerprinting associates with each string a shorter string (its
fingerprint), such that, with high probability, any two distinct strings can be
distinguished by comparing their fingerprints alone. The fingerprints can be
exponentially smaller than the original strings if the parties preparing the
fingerprints share a random key, but not if they only have access to
uncorrelated random sources. In this paper we show that fingerprints consisting
of quantum information can be made exponentially smaller than the original
strings without any correlations or entanglement between the parties: we give a
scheme where the quantum fingerprints are exponentially shorter than the
original strings and we give a test that distinguishes any two unknown quantum
fingerprints with high probability. Our scheme implies an exponential
quantum/classical gap for the equality problem in the simultaneous message
passing model of communication complexity. We optimize several aspects of our
scheme.Comment: 8 pages, LaTeX, one figur
One-loop Quantum Gravity in Schwarzschild Spacetime
The quantum theory of linearized perturbations of the gravitational field of
a Schwarzschild black hole is presented. The fundamental operators are seen to
be the perturbed Weyl scalars and associated with the
Newman-Penrose description of the classical theory. Formulae are obtained for
the expectation values of the modulus squared of these operators in the
Boulware, Unruh and Hartle-Hawking quantum states. Differences between the
renormalized expectation values of both and
in the three quantum states are evaluated
numerically.Comment: 39 pages, 11 Postscript figures, using revte
Effect of Behavioral and Pelvic Floor Muscle Therapy Combined With Surgery Versus Surgery Alone on Incontinence Symptoms Among Women With Mixed Urinary Incontinence: The ESTEEM Randomized Clinical Trial
Public crises, public futures
This article begins to map out a novel approach to analyzing contemporary contexts of public crisis, relationships between them and possibilities that these scenes hold out for politics. The article illustrates and analyses a small selection of examples of these kinds of contemporary scenes and calls for greater attention to be given to the conditions and consequences of different forms and practices of public and political mediation. In offering a three-fold typology to delineate differences between ‘abject’, ‘audience’ and ‘agentic’ publics the article begins to draw out how political and public futures may be seen as being bound up with how the potentialities, capacities and qualities that publics are imagined to have and resourced to perform. Public action and future publics are therefore analysed here in relation to different versions of contemporary crisis and the political concerns and publics these crises work to articulate, foreground and imaginatively and practically support
Diverse capacity for 2-methylhopanoid production correlates with a specific ecological niche
Molecular fossils of 2-methylhopanoids are prominent biomarkers in modern and ancient sediments that have been used as proxies for cyanobacteria and their main metabolism, oxygenic photosynthesis. However, substantial culture and genomic-based evidence now indicates that organisms other than cyanobacteria can make 2-methylhopanoids. Because few data directly address which organisms produce 2-methylhopanoids in the environment, we used metagenomic and clone library methods to determine the environmental diversity of hpnP, the gene encoding the C-2 hopanoid methylase. Here we show that hpnP copies from alphaproteobacteria and as yet uncultured organisms are found in diverse modern environments, including some modern habitats representative of those preserved in the rock record. In contrast, cyanobacterial hpnP genes are rarer and tend to be localized to specific habitats. To move beyond understanding the taxonomic distribution of environmental 2-methylhopanoid producers, we asked whether hpnP presence might track with particular variables. We found hpnP to be significantly correlated with organisms, metabolisms and environments known to support plant–microbe interactions (P-value<10^−6); in addition, we observed diverse hpnP types in closely packed microbial communities from other environments, including stromatolites, hot springs and hypersaline microbial mats. The common features of these niches indicate that 2-methylhopanoids are enriched in sessile microbial communities inhabiting environments low in oxygen and fixed nitrogen with high osmolarity. Our results support the earlier conclusion that 2-methylhopanoids are not reliable biomarkers for cyanobacteria or any other taxonomic group, and raise the new hypothesis that, instead, they are indicators of a specific environmental niche
Electron Beam Freeform Fabrication of Titanium Alloy Gradient Structures
Historically, the structural optimization of aerospace components has been done through geometric methods. A monolithic material is chosen based on the best compromise between the competing design limiting criteria. Then the structure is geometrically optimized to give the best overall performance using the single material chosen. Functionally graded materials offer the potential to further improve structural efficiency by allowing the material composition and/or microstructural features to spatially vary within a single structure. Thus, local properties could be tailored to the local design limiting criteria. Additive manufacturing techniques enable the fabrication of such graded materials and structures. This paper presents the results of a graded material study using two titanium alloys processed using electron beam freeform fabrication, an additive manufacturing process. The results show that the two alloys uniformly mix at various ratios and the resultant static tensile properties of the mixed alloys behave according to rule-of-mixtures. Additionally, the crack growth behavior across an abrupt change from one alloy to the other shows no discontinuity and the crack smoothly transitions from one crack growth regime into another
Stellar Mass--Gas-phase Metallicity Relation at : A Power Law with Increasing Scatter toward the Low-mass Regime
We present the stellar mass ()--gas-phase metallicity relation (MZR)
and its scatter at intermediate redshifts () for 1381 field
galaxies collected from deep spectroscopic surveys. The star formation rate
(SFR) and color at a given of this magnitude-limited ( AB)
sample are representative of normal star-forming galaxies. For masses below
, our sample of 237 galaxies is 10 times larger than those
in previous studies beyond the local universe. This huge gain in sample size
enables superior constraints on the MZR and its scatter in the low-mass regime.
We find a power-law MZR at :
. Our MZR
shows good agreement with others measured at similar redshifts in the
literature in the intermediate and massive regimes, but is shallower than the
extrapolation of the MZRs of others to masses below . The SFR
dependence of the MZR in our sample is weaker than that found for local
galaxies (known as the Fundamental Metallicity Relation). Compared to a variety
of theoretical models, the slope of our MZR for low-mass galaxies agrees well
with predictions incorporating supernova energy-driven winds. Being robust
against currently uncertain metallicity calibrations, the scatter of the MZR
serves as a powerful diagnostic of the stochastic history of gas accretion, gas
recycling, and star formation of low-mass galaxies. Our major result is that
the scatter of our MZR increases as decreases. Our result implies that
either the scatter of the baryonic accretion rate or the scatter of the
-- relation increases as decreases. Moreover, our
measures of scatter at appears consistent with that found for local
galaxies.Comment: 18 pages, 10 figures. Accepted by ApJ. Typos correcte
Campus Vol IX N 1
Howard Studio. Miss Barbara Rasor . Picture. 2.
Shaw, Ted. Cover. Picture. 1.
McIntosh, Bruce. Untitled. Cartoon. 4.
Hostetler, Diane. Adamant Evening . Prose. 5.
Meese, Dorothy. Adamant Evening . Picture. 5.
Anonymous. Whom Not to Invite . Prose. 7.
Ladd, Clyde and Don Duck Shackelford. What Are These People Saying? . Picture. 8.
Umphrey, Shirley. A Year In France . Prose. 10.
Sparian. Untitled. Cartoon. 11.; Anonymous. Untitled. Prose. 11.
Martin, Lyn. The Birth of a Broadcasting Station .
Shaw, Ted. Freud . Cartoon. 12.
Bowman, Jim. A Clear Conscience . Prose. 13.
Freer, Tom and Buzz Peek. The Pigskin Parade . Prose. 15.
Anonymous. Untitled. Cartoon. 16.
Aabye, Nancy. Resentment . Poem. 17.
Hunting, John. Another Tree, Another Hill . Poem. 17.
Miller, John N. Advice From the Mermaid . Poem. 17.
Newman, Brian. Untitled. Cartoon. 17.
Aabye, Nancy. The Poem . Poem. 17.
McIntosh, Bruce. Untitled. Cartoon. 17.
Anonymous. Untitled. Prose. 18.
Wampus. Untitled. Cartoon. 18.
Anonymous. Untitled. Prose. 19.
Schackelford, Don Duck and Ted Shaw. Untitled. Cartoon. 19.
Shaw, Ted. Untitled. Cartoon. 19
Multi-Channel SQUID System for MEG and Ultra-Low-Field MRI
A seven-channel system capable of performing both magnetoencephalography
(MEG) and ultra-low-field magnetic resonance imaging (ULF MRI) is described.
The system consists of seven second-order SQUID gradiometers with 37 mm
diameter and 60 mm baseline, having magnetic field resolution of 1.2-2.8
fT/rtHz. It also includes four sets of coils for 2-D Fourier imaging with
pre-polarization. The system's MEG performance was demonstrated by measurements
of auditory evoked response. The system was also used to obtain a multi-channel
2-D image of a whole human hand at the measurement field of 46 microtesla with
3 by 3 mm resolution.Comment: To appear in Proceedings of 2006 Applied Superconductivity Conferenc
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