Optical Technologies for Future Global Navigation Satellite Systems

Accurate, robust and reliable positioning and timing has become crucial for a wide spectrum of applications. New technologies will further improve the services offered by Global Navigation Satellite Systems (GNSSs). Optical technologies are promising candidates to achieve significant improvements in terms of accuracy, robustness and reliability of GNSSs in near future. First and foremost, optical inter-satellite links (OISLs) and optical clock technologies show enormous potential for future applications at the core of next generation GNSS architectures. Both technologies can be implemented independently from each other in current GNSS as the development lines may differ, in particular in terms of technology readiness. We will present different tracks on how optical key technologies could potentially be integrated in next generations of GNSS, and assess the corresponding improvements

Coat Polymorphism in Eurasian Lynx: Adaptation to Environment or Phylogeographic Legacy?

We studied the relationship between the variability and contemporary distribution of pelage phenotypes in one of most widely distributed felid species and an array of environmental and demographic conditions. We collected 672 photographic georeferenced records of the Eurasian lynx throughout Eurasia. We assigned each lynx coat to one of five phenotypes. Then we fitted the coat patterns to different environmental and anthropogenic variables, as well as the effective geographic distances from inferred glacial refugia. A majority of lynx were either of the large spotted (41.5%) or unspotted (uniform, 36.2%) phenotype. The remaining patterns (rosettes, small spots and pseudo-rosettes) were represented in 11.0%, 7.4%, and 3.9% of samples, respectively. Although various environmental variables greatly affected lynx distribution and habitat suitability, it was the effect of least-cost distances from locations of the inferred refugia during the Last Glacial Maximum that explained the distribution of lynx coat patterns the best. Whereas the occurrence of lynx phenotypes with large spots was explained by the proximity to refugia located in the Caucasus/Middle East, the uniform phenotype was associated with refugia in the Far East and Central Asia. Despite the widely accepted hypothesis of adaptive functionality of coat patterns in mammals and exceptionally high phenotypic polymorphism in Eurasian lynx, we did not find well-defined signs of habitat matching in the coat pattern of this species. Instead, we showed how the global patterns of morphological variability in this large mammal and its environmental adaptations may have been shaped by past climatic change.publishedVersio

MaGiK Method of T-Cell Receptor Repertoire Analysis

T-cell receptor diversity enables the cellular immune response to recognize a broad range of viral and other pathogenic agents. An increasingly common method of characterizing T-cell receptor diversity and usage in response to antigenic challenges involves the identification of clonal expansions by PCR amplification of the CDR3 region of distinct TCRVβ families. Though clonal expansions often appear evident upon visual inspection of the results, a systematic method is needed for the valid enumeration of these expansions. Here, we describe a novel analysis method, termed the MaGiK method, for systematically identifying and enumerating clonal T-cell expansions and for applying the results to investigations of the T-cell receptor repertoire

A Second Isolate of HTLV-II Associated with Atypical Hairy-Cell Leukemia

THE human T-cell lymphotropic viruses Type I (HTLV-I) and Type II (HTLV-II) and the bovine leukemia virus, which are members of a family of leukemogenic mammalian retroviruses, share some of the same structural and functional characteristics. HTLV-I has been implicated as the causative agent of adult T-cell leukemia, a T-cell lymphoid malignant disease endemic to southern Japan and the Caribbean area. 1 2 3 4 5 6 7 8 Bovine leukemia virus has been recognized as a cause of specific lymphoid malignant diseases of cattle. 9 10 11 The role of HTLV-II in human cancer is unclear. This agent is a human retrovirus with a nucleic acid sequence homology to HTLV-I . . 

Validation of Kepler Time and Frequency Transfer on a Terrestrial Range of 10.45km

A bi-directional optical link is established over 10.45 km to perform Two-Way Frequency and Time Transfer (TWFT, TWTT) to validate the system design for Lower Earth Orbit (LEO) to ground links through the atmospheric channel. Binary phase shift keying with a homodyne reception scheme is used to recover the carrier frequency. The time transfer is enabled by optical correlation and dynamic tracking of a 25.6 Gcps transmission spread-sequence with a locally generated reference sequence. An additional data transmission of 50 Mbps is performed on the same channel. Optical references and frequency combs on both sides enable the frequency measurements. Ultra-stable oscillators generate Radio Frequency (RF) references for the time transfer. The performance of the system is evaluated under different atmospheric conditions. Frequency transfer with a stability of 5 · 10^?15 at 1 s gate time. Simultaneous two-way time transfer with a stability of 1 · 10^?13 at 1 s gate time prove the feasibility of the system even through the atmospheric channel