Effects of fade distribution on a mobile satellite downlink and uplink performance in a frequency reuse cellular configuration

In a mobile satellite system with a frequency reuse cellular configuration, significant co-channel interference can be experienced due to the antenna sidelobe level. The signal will be subjected not only to its own fading, but also to the effect of the varying degree of fading on co-channel interferer, and this interference will behave differently in the up and in the down link. This paper presents a quantitative evaluation of the combined effects of fades and co-channel interference on a mobile satellite link

Nimesulide reduces interleukin-1β-induced cyclooxygenase-2 gene expression in human synovial fibroblasts

AbstractObjective To characterize the effects of nimesulide (NIM) on basal and induced cyclo-oxygenase-2 (COX-2) gene expression in human synovial fibroblasts (HSF) and to define the intracellular mechanisms that mediate the changes in COX-2 expression and synthesis in response to the drug.Design HSF were incubated with NIM and NS-398 (0, 0.03, 0.3, 3μg/ml) in the absence or presence of the COX-2 inducers interleukin-1β (IL-1β) or endotoxin (LPS). Treated cells were analysed for COX-2 mRNA and protein by Northern and Western blotting analysis, respectively. Putative transcriptional, post-transcriptional, and signaling effects of NIM on basal and induced-COX-2 expression were investigated by human COX-2 promoter studies, calcium studies, reactive oxygen species (ROS) evaluations, electrophoretic mobility shift analysis (EMSA) and half-life studies of COX-2 mRNA.Results NIM inhibited IL-1β-induced COX-2 expression and protein at sub and therapeutic concentrations (0.03–0.3μg/ml) while the non-specific NSAID, naproxen, did not. Both drugs suppressed PGE2 release by about 95%. NIM had no effect on (1) IL-1β-induced increases in NF-κB or c/EBP signaling, or (2) human COX-2 promoter activity. Stability of induced COX-2 mRNA was unaffected by NIM treatments. Pre-treatment of cells with O2radical scavengers (e.g. PDTC) or with Ca++channel blockers (e.g. verapamil) had a modest effect on IL-1β-induced COX-2 expression. NIM blocked ionomycin+thapsigargin and H2O2-induced increases in COX-2 protein synthesis.Conclusion NIM inhibits cytokine-induced COX-2 expression and protein at sub and therapeutic concentrations. At least part of this activity may be the result of NIM inhibition of calcium and/or free radical generation induced by cytokines

The effect of Bt-transgenic potatoes on the movement of the Colorado potato beetle [Coleoptera : Chrysomelidae]

Une étude de deux saisons au Centre de recherches sur la pomme de terre, Fredericton, Nouveau-Brunswick, a démontré que les adultes du doryphore de la pomme de terre ( Leptinotarsa decemlineata) susceptibles au Bacillus thuringiensis (Bt) avaient un temps de résidence quantifiable dans une parcelle de pomme de terre Bt-transgénique. Cinquante pour cent des doryphores susceptibles au Bt relâchés dans une parcelle de pommes de terre Russet Burbank transgéniques (NewLeaf TM) ont été recapturés de 4 à 7 jours plus tard tandis que la même proportion de recapture des doryphores relâchés dans la parcelle témoin non-transgénique a eu lieu de 7 à 11 jours après le lâcher. En dépit de la toxicité des plantes, les doryphores ont survécu pendant un laps de temps appréciable (jusqu'à 31 jours) dans la parcelle de pommes de terre transgéniques. De 25 à 30 % des doryphores relâchés dans la parcelle de pommes de terre Bt-transgéniques furent recapturés sur des plants-pièges ou dans des pièges-fosse en dehors de cette parcelle, ce qui démontre un niveau élevé de dispersion. La durée du temps de résidence et le haut niveau de dispersion pourraient permettre le développement d'une population de doryphores résistante à la pomme de terre Bt-transgénique. Nos résultats sont utiles pour le développement d'une stratégie de déploiement de la pomme de terre Bt-transgénique qui réduit les risques de résistance au Bt chez le doryphore de la pomme de terre.A two-year field study conducted at the Potato Research Centre in Fredericton, New Brunswick, demonstrated a quantifiable residency time for Bacillus thuringiensis (Bt) susceptible adult Colorado potato beetles (Leptinotarsa decemlineata) in a Bt-transgenic potato field. Fifty percent of Bt-susceptible beetles released in a transgenic Russet Burbank (NewLeafTM) potato plot were recaptured 4 to 7 days after release compared to 7 to 11 days for beetles released in a non-transgenic control plot. Beetles survived for long periods of time (up to 31 days) on transgenic potatoes in spite of the crop's toxicity. A significant number of beetles dispersed from transgenic plots. Twenty-five and 30% of the beetles released in the Bt-transgenic plot were recaptured in border rows or trench traps outside the plot indicating a high level of dispersal activity. The long residency time and the high level of dispersal activity could increase the chances of development of a Bt-resistant beetle population. These findings are important to the development of a deployment strategy that will reduce the risk of build-up of Bt resistance in the beetle population

Fractional Hamiltonian Monodromy from a Gauss-Manin Monodromy

Fractional Hamiltonian Monodromy is a generalization of the notion of Hamiltonian Monodromy, recently introduced by N. N. Nekhoroshev, D. A. Sadovskii and B. I. Zhilinskii for energy-momentum maps whose image has a particular type of non-isolated singularities. In this paper, we analyze the notion of Fractional Hamiltonian Monodromy in terms of the Gauss-Manin Monodromy of a Riemann surface constructed from the energy-momentum map and associated to a loop in complex space which bypasses the line of singularities. We also prove some propositions on Fractional Hamiltonian Monodromy for 1:-n and m:-n resonant systems.Comment: 39 pages, 24 figures. submitted to J. Math. Phy

Post-Eocene extensional tectonics in Southern New Caledonia (SW Pacific): insights from onshore fault analysis and offshore seismic data

Ductile to brittle extensional deformation following thrusting of the peridotites nappe during the Upper Eocene has been shown to play a major role in the Tertiary tectonic evolution of the northern part of the main island of New Caledonia and its eastern and western margins. In this study, we provide new tectonic data from southern New Caledonia that allow to better constrain the tectonic evolution of the southern part of the main island. We present a kinematic analysis of faults and striations obtained mainly from exposures of sedimentary rocks in the region of Noumea with complements from measurements made farther north at Nepoui within post-obduction Middle-Miocene deposits. We also present additional results of an interpretation of seismic lines from the lagoon south of the Noumea Peninsula which provide constraints on the current tectonic regime of southern New Caledonia. Extensional faults in the Noumea region have been studied within terranes of various ages including pre- and syn-obduction deposits and ophiolites. Hence, we demonstrate that important extensional events have affected the southern part of the New Caledonia block after the obduction of the peridotite nappe. The direction of maximum extension is variable at the scale of the region. Both high angle and low angle normal faults are present and block rotation is observed at some localities. This suggests that detachments accommodating significant displacements are cutting through the sedimentary pile. The average final strain pattern of the region can be regarded as the results of a multidirectional flattening, a hypothesis consistent with vertical uplift associated with regional extension. These results are in good agreement with conclusions of earlier workers showing late extensional evolution of the ophiolites alon

Landau levels in the case of two degenerate coupled bands: kagome lattice tight-binding spectrum

The spectrum of charged particles hopping on a kagome lattice in a uniform transverse magnetic field shows an unusual set of Landau levels at low field. They are unusual in two respects: the lowest Landau levels are paramagnetic so their energies decrease linearly with increasing field magnitude, and the spacings between the levels are not equal. These features are shown to follow from the degeneracy of the energy bands in zero magnetic field. We give a general discussion of Landau levels in the case of two degenerate bands, and show how the kagome lattice tight-binding model includes one special case of this more general problem. We also discuss the consequences of this for the behavior of the critical temperature of a kagome grid superconducting wire network, which is the experimental system that originally motivated this work.Comment: 18 pages, 8 figure