434 research outputs found
Defining public discourse : the Fairness Doctrine and Equal Time in American broadcasting
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Bibliography: leaves 301-314.by Hugh Carter Donahue.Ph.D
Quality of service monitoring: Performance metrics across proprietary content domains
We propose a quality of service (QoS) monitoring program for broadband access
to measure the impact of proprietary network spaces. Our paper surveys other
QoS policy initiatives, including those in the airline, and wireless and
wireline telephone industries, to situate broadband in the context of other
markets undergoing regulatory devolution. We illustrate how network
architecture can create impediments to open communications, and how QoS
monitoring can detect such effects. We present data from a field test of
QoS-monitoring software now in development. We suggest QoS metrics to gauge
whether information "walled gardens" represent a real threat for dividing the
Internet into proprietary spaces.
To demonstrate our proposal, we are placing our software on the computers of
a sample of broadband subscribers. The software periodically conducts a battery
of tests that assess the quality of connections from the subscriber's computer
to various content sites. Any systematic differences in connection quality
between affiliated and non-affiliated content sites would warrant research into
the behavioral implications of those differences.
QoS monitoring is timely because the potential for the Internet to break into
a loose network of proprietary content domains appears stronger than ever.
Recent court rulings and policy statements suggest a growing trend towards
relaxed scrutiny of mergers and the easing or elimination of content ownership
rules. This policy environment could lead to a market with a small number of
large, vertically integrated network operators, each pushing its proprietary
content on subscribers.Comment: 29th TPRC Conference, 200
Redox stress shortens lifespan through suppression of respiratory complex I in flies with mitonuclear incompatibilities
Incompatibilities between mitochondrial and nuclear genes can perturb respiration, biosynthesis, signaling and gene expression. Here we investigate whether mild mitonuclear incompatibilities alter the physiological response to redox stress induced by N-acetyl cysteine (NAC). We studied three Drosophila melanogaster lines with mitochondrial genomes that were either coevolved (WT) or mildly mismatched (BAR, COX) to an isogenic nuclear background. Responses to NAC varied substantially with mitonuclear genotype, sex, tissue and dose. NAC caused infertility and high mortality in some groups, but not others. Using tissue-specific high-resolution fluorespirometry, we show that NAC did not alter H2O2 flux but suppressed complex I-linked respiration in female flies, while maintaining a reduced glutathione pool. The high mortality in BAR females was associated with severe (>50 %) suppression of complex I-linked respiration, rising H2O2 flux in the ovaries, and significant oxidation of the glutathione pool. Our results suggest that redox stress is attenuated by the suppression of complex-I linked respiration, to the point of death in some mitonuclear lines. We propose that suppression of complex I-linked respiration is a general mechanism to maintain redox homeostasis in tissues, which could offset oxidative stress in ageing, producing a metabolic phenotype linked with epigenetic changes and age-related decline
High eccentricity planets from the Anglo-Australian Planet Search
We report Doppler measurements of the stars HD187085 and HD20782 which
indicate two high eccentricity low-mass companions to the stars. We find
HD187085 has a Jupiter-mass companion with a ~1000d orbit. Our formal `best
fit' solution suggests an eccentricity of 0.47, however, it does not sample the
periastron passage of the companion and we find that orbital solutions with
eccentricities between 0.1 and 0.8 give only slightly poorer fits (based on RMS
and chi^2) and are thus plausible. Observations made during periastron passage
in 2007 June should allow for the reliable determination of the orbital
eccentricity for the companion to HD187085. Our dataset for HD20782 does sample
periastron and so the orbit for its companion can be more reliably determined.
We find the companion to HD20782 has M sin i=1.77+/-0.22M_JUP, an orbital
period of 595.86+/-0.03d and an orbit with an eccentricity of 0.92+/-0.03. The
detection of such high-eccentricity (and relatively low velocity amplitude)
exoplanets appears to be facilitated by the long-term precision of the
Anglo-Australian Planet Search. Looking at exoplanet detections as a whole, we
find that those with higher eccentricity seem to have relatively higher
velocity amplitudes indicating higher mass planets and/or an observational bias
against the detection of high eccentricity systems.Comment: to appear in MNRA
Observations on Bats from Trinidad, with a Checklist of Species Occurring on the Island
In their comprehensive treatment of the bats of Trinidad, Goodwin and Greenhall (1961) reported 58 species from the island. Subsequent authors (Goodwin and Greenhall, 1962, 1964; Genoways et al., 1973a; LaVal, 1973a, 1973b) have added some species to the list and changed the status of others so that the known chiropteran fauna of Trinidad now comprises 64 species: five emballonurids, one noctilionid, four mormoopids, 36 phyllostomids (see Handley, 1980, for family-group names), one natalid, one furipterid, one thyropterid, seven vespertilionids, and eight molossids. Among the phyllostomids, the subfamilies Phyllostominae (15) and Stenodermatinae (14) are the best represented, whereas only a few species of the other three subfamilies Glossophaginae (four), Carolliinae (one), and Desmodontinae (two)-are present.
In this paper, we report additional data on 55 species. These data add to the available information concerning distribution, reproduction, and molt. Where appropriate, we have included taxonomic comments on the status of Trinidadian populations. Material reported here is the result of three collecting trips to Trinidad led by R.J. Baker
Convicts and coolies : rethinking indentured labour in the nineteenth century
This article seeks to shift the frame of analysis within which discussions of Indian indentured migration take place. It argues that colonial discourses and practices of indenture are best understood not with regard to the common historiographical framework of whether it was 'a new system of slavery', but in the context of colonial innovations in incarceration and confinement. The article shows how Indian experiences of and knowledge about transportation overseas to penal settlements informed in important ways both their own understandings and representations of migration and the colonial practices associated with the recruitment of indentured labour. In detailing the connections between two supposedly different labour regimes, it thus brings a further layer of complexity to debates around their supposed distinctions
Paralic foraminiferal record of seven large Holocene earthquakes in eastern New Zealand
Abstrac
The observed distribution of spectroscopic binaries from the Anglo-Australian Planet Search
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.We report the detection of sixteen binary systems from the Anglo-Australian Planet Search. Solutions to the radial velocity data indicate that the stars have companions orbiting with a wide range of masses, eccentricities and periods. Three of the systems potentially contain brown-dwarf companions while another two have eccentricities that place them in the extreme upper tail of the eccentricity distribution for binaries with periods less than 1000 d. For periods up to 12 years, the distribution of our stellar companion masses is fairly flat, mirroring that seen in other radial velocity surveys, and contrasts sharply with the current distribution of candidate planetary masses, which rises strongly below 10 MJ. When looking at a larger sample of binaries that have FGK star primaries as a function of the primary star metallicity, we find that the distribution maintains a binary fraction of ∼43 ± 4 per cent between −1.0 and +0.6 dex in metallicity. This is in stark contrast to the giant exoplanet distribution. This result is in good agreement with binary formation models that invoke fragmentation of a collapsing giant molecular cloud, suggesting that this is the dominant formation mechanism for close binaries and not fragmentation of the primary star's remnant protoplanetary disc.Peer reviewe
- …