Bidirectional link mock-up for avionics applications

Copper-based networks have been extensively employed on aircraft to ensure the avionics data-communications. Since the Airbus A380 development, Avionic Data Communication Network (ADCN) has been implemented to ensure transmissions between avionic equipment. This system is based on the Avionic Full Duplex Ethernet (AFDX), and transfers data at rates up to 100 Mb/s. The need of faster communications systems, up to 1Gb/s, has led to great interest in fiber optic based networks. Beyond higher data rates capabilities, the fiber optics have additional benefits, compared to electrical cables, in terms of weight saving and electromagnetic interference immunity which is strongly needed at gigahertz bandwidths. Multimode fibers (MMF) are becoming increasingly attractive for short-haul (<300m) high-speed interconnections. Besides, Vertical Cavity Surface Emitting Lasers (VCSELs) present interesting performances in comparison to edge-emitting lasers, cost effective and are widely chosen in this type of applications. We aim at achieving an entirely optical fiber Gigabit Ethernet (GbE) link based on 850nm VCSELs to interconnect avionic equipments. To meet IEEE 802.3 standards [1] and ADCN requirements [2], the fiber optic link must be full-duplex, bi-directional, on a single wavelength, and on the same fiber on up to 100m-distance. We have used, at each side of the link, a transceiver module developed for harsh environment applications. Also, there are multiple connections due to production breaks. These connections give birth to return loss (RL) and consequently crosstalk. One might pay attention to the impact of the RL on the link. We present the characterization of a mock-up and the comparison of experimental results with the GbE requirements

Ambient halocarbon mixing ratios in 45 Chinese cities

During this study 158 whole air samples were collected in 45 Chinese cities in January and February 2001. The spatial distribution of different classes of halocarbons in the Chinese urban atmosphere, including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), Halon-1211, and other chlorinated compounds is presented and discussed. Most of these compounds were enhanced compared to background levels. However, the mean enhancement of CFCs was relatively small, with CFC-12 and CFC-11 increases of 6% (range 1-31%) and 10% (range 2-89%), respectively, with respect to the global background. On the contrary, strongly enhanced levels of CFC replacement compounds and halogenated compounds used as solvents were measured. The average Halon-1211 concentration exceeded the background of 4.3 pptv by 75% and was higher than 10 pptv in several cities. Methyl chloride mixing ratios were also strongly elevated (78% higher than background levels), which is likely related to the widespread use of coal and biofuel in China. © 2006 Elsevier Ltd. All rights reserved

The Discovery of Extended Thermal X-ray Emission from PKS 2152-699: Evidence for a `Jet-cloud' Interaction

A Chandra ACIS-S observation of PKS 2152-699 reveals thermal emission from a diffuse region around the core and a hotspot located 10" northeast from the core. This is the first detection of thermal X-ray radiation on kiloparsec scales from an extragalactic radio source. Two other hotspots located 47" north-northeast and 26" southwest from the core were also detected. Using a Raymond-Smith model, the first hotspot can be characterized with a thermal plasma temperature of 2.6$\times10^6$ K and an electron number density of 0.17 cm$^{-3}$. These values correspond to a cooling time of about 1.6$\times10^7$ yr. In addition, an emission line from the hotspot, possibly Fe xxv, was detected at rest wavelength 10.04\AA. The thermal X-ray emission from the first hotspot is offset from the radio emission but is coincident with optical filaments detected with broadband filters of HST/WFPC2. The best explanation for the X-ray, radio, and optical emission is that of a `jet-cloud' interaction. The diffuse emission around the nucleus of PKS 2152-699 can be modeled as a thermal plasma with a temperature of 1.2$\times10^7$ K and a luminosity of 1.8$\times10^{41}$ erg s$^{-1}$. This emission appears to be asymmetric with a small extension toward Hotspot A, similar to a jet. An optical hotspot (EELR) is seen less than an arcsecond away from this extension in the direction of the core. This indicates that the extension may be caused by the jet interacting with an inner ISM cloud, but entrainment of hot gas is unavoidable. Future observations are discussed.Comment: To appear in the Astrophysical Journal 21 pages, 5 Postscript figures, 1 table, AASTeX v. 5.

Closing the Loophole: A Case Study of Organizing for More Equitable and Affordable Access to Health Care in San Francisco

This paper presents in-depth case study of a successful hybrid political and community organizing campaign to ensure equitable access to health care through the perspective of a grassroots San Francisco community-based organization, the Chinese Progressive Association (CPA), which has been organizing low-income Chinese immigrants for over four decades. First, it outlines the Health Care Security Ordinance (HCSO), which, since its passage in 2006, has established a near-universal health care access program, helping to make health care accessible and affordable to individuals living and working in San Francisco. Then it presents the campaign to save the HCSO, focusing on CPA’s participation in the HCSO coalition. Finally, it discusses health care as it relates to the San Francisco’s affordability crisis and the political economic context in which it is taking place. Despite the limitations inherent in small case studies like this one, it nevertheless provides a valuable opportunity to better understand how one politically progressive city attempted to address the problem of grossly inequitable health care access through the lens of community organizing, advocacy, and coalition building. San Francisco, like many major American cities today, is being confronted with rapid gentrification and growing economic inequality—the backdrop to the HCSO. Through innovative experiments in social responsibility like the HCSO, however, the city has made leaps in health care access. It concludes with lessons learned from local organizing and advocacy to save the HCSO as these may inform other local efforts to promote health care for all

Review of Higher Education Access and Outcomes for Aboriginal and Torres Strait Islander People: Final Report

National review into Indigenous higher education issue

Inhibition by small-molecule ligands of formation of amyloid fibrils of an immunoglobulin light chain variable domain.

Overproduction of immunoglobulin light chains leads to systemic amyloidosis, a lethal disease characterized by the formation of amyloid fibrils in patients' tissues. Excess light chains are in equilibrium between dimers and less stable monomers which can undergo irreversible aggregation to the amyloid state. The dimers therefore must disassociate into monomers prior to forming amyloid fibrils. Here we identify ligands that inhibit amyloid formation by stabilizing the Mcg light chain variable domain dimer and shifting the equilibrium away from the amyloid-prone monomer