4,342 research outputs found
The Work of WM. Loehe in North America
The Work of WM. Loehe in North Americ
Brief Studies
The Function of the Law in Christian Preaching
Ezra’s Bible School
Basic Books for the Exeget
Disk assembly and the MBH–σe relation of supermassive black holes
Recent Hubble Space Telescope observations have revealed that a majority of active galactic nuclei (AGNs) at z ∼ 1–3 are resident in isolated disk galaxies, contrary to the usual expectation that AGNs are triggered by mergers. Here we develop a new test of the cosmic evolution of supermassive black holes (SMBHs) in disk galaxies by considering the local population of SMBHs. We show that substantial SMBH growth in spiral galaxies is required as disks assemble. SMBHs exhibit a tight relation between their mass and the velocity dispersion of the spheroid within which they reside, the M•–σe relation. In disk galaxies the bulge is the spheroid of interest. We explore the evolution of the M•–σe relation when bulges form together with SMBHs on the M•–σe relation and then slowly re-form a disk around them. The formation of the disk compresses the bulge, raising its σe. We present evidence for such compression in the form of larger velocity dispersion of classical bulges compared with elliptical galaxies at the same mass. This compression leads to an offset in the M•–σe relation if it is not accompanied by an increased M•. We quantify the expected offset based on photometric data and show that, on average, SMBHs must grow by ∼50%–65% just to remain on the M•–σe relation. We find no significant offset in the M•–σe relations of classical bulges and of ellipticals, implying that SMBHs have been growing along with disks. Our simulations demonstrate that SMBH growth is necessary for the local population of disk galaxies to have remained on the M•–σe relation.peer-reviewe
An all-Ireland epidemiological study of MND, 2004-2005
Background and methods: We conducted an all-Ireland population-based prospective epidemiological survey of motor neurone disease (MND) using the Northern Ireland and Republic of Ireland MND registers to examine the incidence and prevalence of the disease over the period 2004–2005.Results and conclusions: Incidence of MND was 1.9 per 100 000 person-years and rates were comparable in both the north and south of Ireland. Prevalence of MND was 5.0 per 100 000 population. When compared with previous published surveys of MND performed in the Republic of Ireland over the last 10 years, rates of disease have remained relatively constant. When standardized to the 1990 US population, the incidence of MND in Ireland was found to be consistent with other European prospective surveys of MND
Antiretroviral therapy to prevent HIV acquisition in serodiscordant couples in a hyperendemic community in rural South Africa
Background. Antiretroviral therapy (ART) was highly efficacious in preventing human immunodeficiency virus (HIV) transmission in stable serodiscordant couples in the HPTN-052 study, a resource-intensive randomized controlled trial with near-perfect ART adherence and mutual HIV status disclosure among all participating couples. However, minimal evidence exists of the effectiveness of ART in preventing HIV acquisition in stable serodiscordant couples in "real-life" population-based settings in hyperendemic communities of sub-Saharan Africa, where health systems are typically resource-poor and overburdened, adherence to ART is often low, and partners commonly do not disclose their HIV status to each other.
Methods. Data arose from a population-based open cohort in KwaZulu-Natal, South Africa. A total of 17 016 HIV-uninfected individuals present between January 2005 and December 2013 were included. Interval-censored time-updated proportional hazards regression was used to assess how the ART status affected HIV transmission risk in stable serodiscordant relationships.
Results. We observed 1619 HIV seroconversions in 17 016 individuals, over 60 349 person-years follow-up time. During the follow-up period, 1846 individuals had an HIV-uninfected and 196 had an HIV-infected stable partner HIV incidence was 3.8/100 person-years (PY) among individuals with an HIV-infected partner (95% confidence interval [CI], 2.3-5.6), 1.4/100 PY (.4-3.5) among those with HIV-infected partners receiving ART, and 5.6/100 PY (3.5-8.4) among those with HIV-infected partners not receiving ART. Use of ART was associated with a 77% decrease in HIV acquisition risk among serodiscordant couples (adjusted hazard ratio, 0.23; 95% CI,. 07-.80).
Conclusions. ART initiation was associated with a very large reduction in HIV acquisition in serodiscordant couples in rural KwaZulu-Natal. However, this "real-life" effect was substantially lower than the effect observed in the HPTN-052 trial. To eliminate HIV transmission in serodiscordant couples, additional prevention interventions are probably needed
Compact non-invasive millimeter-wave glucose sensor
The authors describe a compact non-invasive CMOS-circuit-based glucose monitor using millimeter-wave transmission for use on animal and human subjects. Using an earlier device, in vivo measurements were performed through the ear in anesthetized animals and correlated with blood glucose concentration from test strips. In addition, millimeter wave absorption through glucose-containing solutions was measured in specialized liquid transmission cells and is shown to correlate with the animal and separate in vitro data. Design and performance information on the CMOS transceiver are given
Fabricating PFPE Membranes for Microfluidic Valves and Pumps
A process has been developed for fabricating membranes of a perfluoropolyether (PFPE) and integrating them into valves and pumps in laboratory-on-achip microfluidic devices. Membranes of poly(tetrafluoroethylene) [PTFE] and poly(dimethylsilane) [PDMS] have been considered for this purpose and found wanting. By making it possible to use PFPE instead of PTFE or PDMS, the present process expands the array of options for further development of microfluidic devices for diverse applications that could include detection of biochemicals of interest, detection of toxins and biowarfare agents, synthesis and analysis of proteins, medical diagnosis, and synthesis of fuels
Internal alignments of red versus blue discs in dark matter haloes
Large surveys have shown that red galaxies are preferentially aligned with their haloes, while blue galaxies have a more isotropic distribution. Since haloes generally align with their filaments, this introduces a bias in the measurement of the cosmic shear from weak lensing. It is therefore vitally important to understand why this difference arises. We explore the stability of different disc orientations within triaxial haloes. We show that, in the absence of gas, the disc orientation is most stable when its spin is along the minor axis of the halo. Instead when gas cools on to a disc, it is able to form in almost arbitrary orientation, including off the main planes of the halo (but avoiding an orientation perpendicular to the halo's intermediate axis). Substructure helps gasless galaxies reach alignment with the halo faster, but has less effect on galaxies when gas is cooling on to the disc. Our results provide a novel and natural interpretation for why red, gas poor galaxies are preferentially aligned with their halo, while blue, star-forming, galaxies have nearly random orientations, without requiring a connection between galaxies' current star formation rate and their merger histor
Internal alignments of red versus blue discs in dark matter haloes
Large surveys have shown that red galaxies are preferentially aligned with their haloes, while blue galaxies have a more isotropic distribution. Since haloes generally align with their filaments, this introduces a bias in the measurement of the cosmic shear from weak lensing. It is therefore vitally important to understand why this difference arises. We explore the stability of different disc orientations within triaxial haloes. We show that, in the absence of gas, the disc orientation is most stable when its spin is along the minor axis of the halo. Instead when gas cools on to a disc, it is able to form in almost arbitrary orientation, including off the main planes of the halo (but avoiding an orientation perpendicular to the halo's intermediate axis). Substructure helps gasless galaxies reach alignment with the halo faster, but has less effect on galaxies when gas is cooling on to the disc. Our results provide a novel and natural interpretation for why red, gas poor galaxies are preferentially aligned with their halo, while blue, star-forming, galaxies have nearly random orientations, without requiring a connection between galaxies' current star formation rate and their merger history
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