Measurement results of transmit delay diversity for DVB-T networks

This paper describes work carried out by Brunel University and Broadreach systems (UK) to quantify the advantages that can be achieved if transmit diversity is applied to systems employing the DVB standard. The techniques investigated can be applied to standard receiver equipment without modification. An extensive and carefully planned field trial performed during the winter of 2007/2008 in Uxbridge (UK) is described. The transmissions were performed in the 730 MHz frequency band with a DVB-T transmitter and a mean power of 18.4 dBW. Transmit delay diversity has been observed to deliver significant reception improvement in automotive- non line of sight situations

Potassium channel activators protect the N-methyl-D-aspartate-induced cerebral vascular dilation after combined hypoxia and ischemia in piglets

Background and Purpose-Cerebral arteriolar dilation to N-methyl-D-aspartate (NMDA) is a neuronally mediated multistep process that is sensitive to cerebral hypoxia and ischemia (H/I). We tested the hypothesis that topical pretreatment with the selective potassium channel agonists NS1619 and aprikalim preserves the vascular response to NMDA after consecutive WI. Methods-Pial arteriolar diameters were measured in anesthetized piglets with the use of a closed cranial window and intravital microscopy, Arteriolar responses to NMDA (10(-5), 5 x 10(-5), and 10(-4) mol/L) were recorded before and 1 hour after 10 minutes of hypoxia (8.5% O-2 in N-2) plus; 10 minutes of ischemia (WI), Ischemia was induced by increasing intracranial pressure, Subgroups were topically pretreated with 10(-5) mol/L NS1619, 10(-6) mol/L aprikalim, 10(-6) mol/L calcitonin gene-related peptide (CGRP), or 10(-5) mol/L papaverine. We also examined the effects of H/I on vascular responses to kainate (10(-4) mol/L) to assess specificity of neuronal injury. Results-Arteriolar responses to NMDA were significantly attenuated after WI. Baseline compared with post-WI arteriolar diameters were 9+/-4% versus 3+/-2% at 10(-5) mol/L, 22+/-4% versus 4+/-2% at 5 x 10(-5) mol/L, and 33+/-4% versus 7+/-2% at 10(-4) mol/L (mean+/-SE; all P<.05, n=7), Pretreatment with NS1619 and aprikalim preserved the arteriolar responses to NMDA after WI, For NS1619 (n=6), values were as follows: 9+/-2% versus 6+/-4% at 10(-5) mol/L, 19+/-6% versus 21+/-5% at 5x10(-5) mol/L, and 35+/-3% versus 31+/-5% at 10(-4) mol/L, For aprikalim (n=7), values were as follows: 6+/-2% versus 8+/-2% at 10(-5) mol/L, 22+/-6% versus 15+/-3% at 5x10(-5) mol/L, and 41+/-5% versus 32+/-6% at 10(-4) mol/L. In contrast, piglets pretreated with CGRP (n=6) or papaverine (n=5) showed no preservation of the vascular response to NMDA after WI, although these compounds dilated the arterioles to an extent similar to that with NS1619/aprikalim. Kainate-induced arteriolar dilation (n=6) was largely preserved after H/I compared with preischemic responses, Conclusions-(1) Vascular responses of cerebral arterioles to NMDA after H/I are preserved by pretreatment with NS1619 or aprikalim, indicating a neuroprotective effect, (2) CGRP and papaverine do not preserve the vascular response to NMDA despite causing vasodilation similar to that with NS1619 or aprikalim, This suggests that activation of potassium channels on neurons accounts for the protective effect of potassium channel agonists, (3) Preserved arteriolar dilation to kainate suggests largely intact functioning of neuronal nitric oxide synthase after H/I

Evaluation of diversity gains for DVB-T systems

Copyright @ 2008 Eurescom GmbHThe requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed costeffectively and with minimized environmental impact. The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of transmit and receive diversity gains with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using the Spirent dual channel emulator

Comment on ``Neutrino oscillations in the early universe: how can large lepton asymmetry be generated?"

We comment on the recent paper by A. D. Dolgov, S. H. Hansen, S. Pastor and D. V. Semikoz (DHPS) [Astropart. Phys. {\bf 14}, 79 (2000)] on the generation of neutrino asymmetries from active-sterile neutrino oscillations. We demonstrate that the approximate asymmetry evolution equation obtained therein is an expansion, up to a minor discrepancy, of the well-established static approximation equation, valid only when the supposedly new higher order correction term is small. In the regime where this so-called ``back-reaction'' term is large and artificially terminates the asymmetry growth, their evolution equation ceases to be a faithful approximation to the Quantum Kinetic Equations (QKEs) simply because pure Mikheyev-Smirnov-Wolfenstein (MSW) transitions have been neglected. At low temperatures the MSW effect is the dominant asymmetry amplifier. Neither the static nor the DHPS approach contains this important physics. Therefore we conclude that the DHPS results have sufficient veracity at the onset of explosive asymmetry generation, but are invalid in the ensuing low temperature epoch where MSW conversions are able to enhance the asymmetry to values of order $0.2 - 0.37$. DHPS do claim to find a significant final asymmetry for very large $\delta m^2$ values. However, for this regime the effective potential they employed is not valid.Comment: RevTeX, 32 pages, including 4 embedded figures; this version to appear in Astropart.Phy

Active-sterile neutrino oscillations in the early Universe: asymmetry generation at low |delta m^2| and the Landau-Zener approximation

It is well established that active-sterile neutrino oscillations generate large neutrino asymmetries for very small mixing angles ($\sin^2 2\theta_0\lesssim 10^{-4}$), negative values of $\delta m^2$ and provided that $|\delta m^2|\gtrsim 10^{-4} {\rm eV^2}$. By numerically solving the quantum kinetic equations, we show that the generation still occurs at much lower values of $|\delta m^2|$. We also describe the borders of the generation at small mixing angles and show how our numerical results can be analytically understood within the framework of the Landau-Zener approximation thereby extending previous work based on the adiabatic limit. This approximate approach leads to a fair description of the MSW dominated regime of the neutrino asymmetry evolution and is also able to correctly reproduce its final value. We also briefly discuss the impact that neutrino asymmetry generation could have on big bang nucleosynthesis, CMBR and relic neutrinos.Comment: 29 pages, 8 figures; to appear on Phys. ReV. D; figure 7 added, new curves in figure 5a, new figure

Foreword to When a Woman Campaigns: Emily Sloan\u27s Races to Become Montana\u27s First Female County Attorney

This essay introduces Emily Sloan and her races to become Montana\u27s first female county attorney

Constitutional Initiative 30: What Constitutional Rights Did Montanans Surrender in Hopes of Securing Liability Insurance?

Constitutional Initiative 30: What Constitutional Rights Did Montanans Surrender in Hopes of Securing Liability Insurance

Foreword to When a Woman Campaigns: Emily Sloan\u27s Races to Become Montana\u27s First Female County Attorney

Emily Sloan is a remarkable figure in Montana history—a brave and resolute woman who practiced law for nearly twenty years and ran for public office seven times early in the twentieth century. She practiced law because that was the best of the escape routes open to her, and she obediently ran for office to boost her chances of succeeding at law. Although neither practicing law nor running for public office were her first choices, she committed herself wholeheartedly to those enterprises. She remained true to her calling as well: she never gave up her writing. At her death, she left behind a memoir, a volume of published poetry, a published novel, many short stories, hundreds of unpublished poems, a journal of her last few years, letters, and more. At the risk of dispensing with professorial or professional objectivity, I offer my hope that you enjoy this small chapter in Emily’s life story

Afterword: Pulling for the Shore of Independence

This article traces the story of Emily Mullenger Sloan one of Montana\u27s first women lawyers

Legal Writing (Groups) at the University of Montana: Professional Voice Lessons in a Communal Context

Legal Writing (Groups) at the University of Montana: Professional Voice Lessons in a Communal Contex