748 research outputs found
Independent individual addressing of multiple neutral atom qubits with a MEMS beam steering system
We demonstrate a scalable approach to addressing multiple atomic qubits for
use in quantum information processing. Individually trapped 87Rb atoms in a
linear array are selectively manipulated with a single laser guided by a MEMS
beam steering system. Single qubit oscillations are shown on multiple sites at
frequencies of ~3.5 MHz with negligible crosstalk to neighboring sites.
Switching times between the central atom and its closest neighbor were measured
to be 6-7 us while moving between the central atom and an atom two trap sites
away took 10-14 us.Comment: 9 pages, 3 figure
Porcine and Human intestinal cells for profiling the capacity of colonization and infection of the foodborne pathogen Yersinia enterocolitica
Y. enterocolitica is the third bacterial cause of human enteritis in Europe. The species is divided into six biotypes (BT), BT1A regarded as nonpathogenic and pathogenic biotypes 1B, 2, 3, 4 and 5. Pigs, the principal reservoir for human pathogenic strains, do not develop clinical signs. The BT4 is the most frequently biotype isolated from pig and encountered in human yersiniosis. This study investigated the use of in vitro cultured cells to assess the ability of Y. enterocolitica to adhere and invade pig and human cells. We tested in vitro the adhesion and invasion abilities of a collection of 23 Y. enterocolitica on intestinal pork cells IPEC-J2 and on human intestinal cells Caco-2. The overall profile of adhesion / invasion was different in the both tests. Nevertheless, in the two tests, the BT1A and the BT5 strains, which are rarely isolated from pigs, show a low capacity to adhere and to invade. These strains were clustered in the class 1. The class 2, forming by strains having a greater efficiency of adhesion and/or a greater efficiency of invasion, contained predominantly strains of BT4. The results obtained in this study reflect the ability of BT4 to colonize pigs and the low capacity to BT1A and BT5 to colonize pigs and humans
On Nori's Fundamental Group Scheme
We determine the quotient category which is the representation category of
the kernel of the homomorphism from Nori's fundamental group scheme to its
\'etale and local parts. Pierre Deligne pointed out an error in the first
version of this article. We profoundly thank him, in particular for sending us
his enlightning example reproduced in Remark 2.4 2).Comment: 29 page
Complete Genome Sequence of Mannheimia varigena Isolated from Bovine Milk
peer-reviewedMannheimia varigena is a pathogen of cattle that has been isolated from diseased lung and udder. There are currently complete genome sequences for 4 M. varigena isolates, all from lungs of cattle in the United States. We report a complete genome sequence of M. varigena isolated from bovine milk in Ireland
The Neron-Severi group of a proper seminormal complex variety
We prove a Lefschetz (1,1)-Theorem for proper seminormal varieties over the
complex numbers. The proof is a non-trivial geometric argument applied to the
isogeny class of the Lefschetz 1-motive associated to the mixed Hodge structure
on H^2.Comment: 16 pages; Mathematische Zeitschrift (2008
Simply connected projective manifolds in characteristic have no nontrivial stratified bundles
We show that simply connected projective manifolds in characteristic
have no nontrivial stratified bundles. This gives a positive answer to a
conjecture by D. Gieseker. The proof uses Hrushovski's theorem on periodic
points.Comment: 16 pages. Revised version contains a more general theorem on torsion
points on moduli, together with an illustration in rank 2 due to M. Raynaud.
Reference added. Last version has some typos corrected. Appears in
Invent.math
PHARAO Laser Source Flight Model: Design and Performances
In this paper, we describe the design and the main performances of the PHARAO
laser source flight model. PHARAO is a laser cooled cesium clock specially
designed for operation in space and the laser source is one of the main
sub-systems. The flight model presented in this work is the first
remote-controlled laser system designed for spaceborne cold atom manipulation.
The main challenges arise from mechanical compatibility with space constraints,
which impose a high level of compactness, a low electric power consumption, a
wide range of operating temperature and a vacuum environment. We describe the
main functions of the laser source and give an overview of the main
technologies developed for this instrument. We present some results of the
qualification process. The characteristics of the laser source flight model,
and their impact on the clock performances, have been verified in operational
conditions.Comment: Accepted for publication in Review of Scientific Instrument
Chamber basis of the Orlik-Solomon algebra and Aomoto complex
We introduce a basis of the Orlik-Solomon algebra labeled by chambers, so
called chamber basis. We consider structure constants of the Orlik-Solomon
algebra with respect to the chamber basis and prove that these structure
constants recover D. Cohen's minimal complex from the Aomoto complex.Comment: 16 page
Differential Forms on Log Canonical Spaces
The present paper is concerned with differential forms on log canonical
varieties. It is shown that any p-form defined on the smooth locus of a variety
with canonical or klt singularities extends regularly to any resolution of
singularities. In fact, a much more general theorem for log canonical pairs is
established. The proof relies on vanishing theorems for log canonical varieties
and on methods of the minimal model program. In addition, a theory of
differential forms on dlt pairs is developed. It is shown that many of the
fundamental theorems and techniques known for sheaves of logarithmic
differentials on smooth varieties also hold in the dlt setting.
Immediate applications include the existence of a pull-back map for reflexive
differentials, generalisations of Bogomolov-Sommese type vanishing results, and
a positive answer to the Lipman-Zariski conjecture for klt spaces.Comment: 72 pages, 6 figures. A shortened version of this paper has appeared
in Publications math\'ematiques de l'IH\'ES. The final publication is
available at http://www.springerlink.co
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