377 research outputs found
Hermitian modular forms congruent to 1 modulo p
For any natural number and any prime not
dividing there is a Hermitian modular form of arbitrary genus over
L:=\Q [\sqrt{-\ell}] that is congruent to 1 modulo which is a Hermitian
theta series of an -lattice of rank admitting a fixed point free
automorphism of order . It is shown that also for non-free lattices such
theta series are modular forms
Legionella pneumophila: an aquatic microbe goes astray
Legionella pneumophila is naturally found in fresh water were the bacteria parasitize within protozoa. It also survives planctonically in water or biofilms. Upon aerosol formation via man-made water systems, L. pneumophila can enter the human lung and cause a severe form of pneumonia, called Legionnaires’ disease. The pathogenesis of Legionnaires’ disease is largely due to the ability of L. pneumophila to invade and grow within macrophages. An important characteristic of the intracellular survival strategy is the replication within the host vacuole that does not fuse with endosomes or lysosomes. In recent times a great number of bacterial virulence factors which affect growth of L. pneumophila in both macrophages and protozoa have been identified. The ongoing Legionella genome project and the use of genetically tractable surrogate hosts are expected to significantly contribute to the understanding of bacterium–host interactions and the regulation of virulence traits during the infection cycle. Since person-to-person transmission of legionellosis has never been observed, the measures for disease prevention have concentrated on eliminating the pathogen from water supplies. In this respect detection and analysis of Legionella in complex environmental consortia become increasingly important. With the availability of new molecular tools this area of applied research has gained new momentum
Marine sponges as microbial fermenters
The discovery of phylogenetically complex, yet highly sponge-specific microbial communities in marine sponges, including novel lineages and even candidate phyla, came as a surprise. At the same time, unique research opportunities opened up, because the microorganisms of sponges are in many ways more accessible than those of seawater. Accordingly, we consider sponges as microbial fermenters that provide exciting new avenues in marine microbiology and biotechnology. This review covers recent findings regarding diversity, biogeography and population dynamics of sponge-associated microbiota, and the data are discussed within the larger context of the microbiology of the ocean
Three-color Sagnac source of polarization-entangled photon pairs
We demonstrate a compact and stable source of polarization-entangled pairs of
photons, one at 810 nm wavelength for high detection efficiency and the other
at 1550 nm for long-distance fiber communication networks. Due to a novel
Sagnac-based design of the interferometer no active stabilization is needed.
Using only one 30 mm ppKTP bulk crystal the source produces photons with a
spectral brightness of 1.13x10^6 pairs/s/mW/THz with an entanglement fidelity
of 98.2%. Both photons are single-mode fiber coupled and ready to be used in
quantum key distribution (QKD) or transmission of photonic quantum states over
large distances.Comment: 7 pages, 4 figure
Deployment Opportunities for DPS-QKD in the Co-Existence Regime of Lit GPON / NG-PON2 Access Networks
We demonstrate cost-effective QKD integration for GPON and NG-PON2. Operation
at 5.1e-7 secure bits/pulse and a QBER of 3.28% is accomplished for a 13.5-km
reach, 2:16-split PON, with 0.52% co-existence penalty for 19 classical
channels
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