62 research outputs found
Numerical simulations on the relative importance of starbursts and AGN in ultra-luminous infrared galaxies
We investigate the relative importance of starbursts and AGN in nuclear
activities of ultra-luminous infrared galaxies (ULIRGs) based on chemodynamical
simulations combined with spectrophotometric synthesis codes. We numerically
investigate both the gas accretion rates (m_acc) onto super massive black holes
(SMBHs) and the star formation rates (m_sf) in ULIRGs formed by gas-rich galaxy
mergers and thereby discuss what powers ULIRGs. Our principal results, which
can be tested against observations, are as follows. (1) ULIRGs powered by AGN
can be formed by major merging between luminous, gas-rich disk galaxies with
prominent bulges containing SMBHs, owing to the efficient gas fuelling m_acc >
1 M_sun/yr of the SMBH. AGN in these ULIRGs can be surrounded by compact
poststarburst stellar populations (e.g., A-type stars). (2) ULIRGs powered by
starbursts with m_sf ~ 100 M_sun/yr can be formed by merging between gas-rich
disk galaxies with small bulges having the bulge-to-disk-ratio (f_b) as small
as 0.1. (3) The relative importance of starbursts and AGN can depend on
physical properties of merger progenitor disks, such as f_b, gas mass fraction,
and total masses. For example, more massive galaxy mergers are more likely to
become AGN-dominated ULIRGs. (4) For most models, major mergers can become
ULIRGs, powered either by starbursts or by AGN, only when the two bulges
finally merge. Interacting disk galaxies can become ULIRGs with well separated
two cores (> 20kpc) at their pericenter when they are very massive and have
small bulges. (5) Irrespective of the choice of model, interacting/merging
galaxies show the highest accretion rates onto the central SMBHs, and the
resultant rapid growth of the SMBHs occur when their star formation rates are
very high.Comment: 18 pages, 15 figures (f1.jpg for color figure of figure 1), accepted
in MNRA
GABAA receptor subtype involvement in addictive behaviour
GABAA receptors form the major class of inhibitory neurotransmitter receptors in the mammalian brain. This review sets out to summarise the evidence that variations in genes encoding GABAA receptor isoforms are associated with aspects of addictive behaviour in humans, while animal models of addictive behaviour also implicate certain subtypes of GABAA receptor. In addition to outlining the evidence for the involvement of specific subtypes in addiction, we summarise the particular contributions of these isoforms in control over the functioning of brain circuits, especially the mesolimbic system, and make a first attempt to bring together evidence from several fields to understanding potential involvement of GABAA Receptor Subtypes in addictive behaviour. While the weight of the published literature is on alcohol dependency, the underlying principles outlined are relevant across a number of different aspects of addictive behaviour
The Application of Reasoning to the Evaluation of Fundamental Differences in Handwriting Comparisons
CYP26A1 gene promoter is a useful tool for reporting RAR-mediated retinoid activity
Of numerous genes regulated by retinoic acid (RA), CYP26A1 is the most inducible gene by RA. In this study, we have used a shortened construct form, E4, of the CYP26A1 gene promoter, in a promoter-less vector with either luciferase or red fluorescent protein (RFP) as the reporter gene and have tested its responses to retinoids in transfected HepG2 and HEK293T cells. The promoter responded linearly to a wide concentration range of RA in cells cotransfected with retinoic acid receptors. It also responded quantitatively to retinol and other retinoids. An isolated clonal line of HEK293T cells permanently transfected with the promoter driving the expression of RFP responded to both RA and retinol, and the responses could be measured by fluorescence microscopy and flow cytometry. The promoter was used to assess the retinoid activity of 3 novel synthetic retinoid analogues, as well as of the intact serum samples of rats. Among the synthetic retinoid analogues tested, EC23 is more potent than RA at lower concentrations and was more stable than RA. The retinoid activities could be measured in control rat serum samples and were increased in the serum of RA-treated rats. This system offers a biologically-based alternative to mass-based retinoid analysis
Evaluating the accuracy of morphological identification of insect pests of rice crops using DNA barcoding
Park characteristics, use, and physical activity: A review of studies using SOPARC (System for Observing Play and Recreation in Communities)
The System for Observing Play and Recreation in Communities (SOPARC) can obtain information on park users and their physical activity using momentary time sampling. We conducted a literature review of studies using the SOPARC tool to describe the observational methods of each study, and to extract public park use overall and by demographics and physical activity levels. We searched PubMed, Embase, and SPORTDiscus for full-length observational studies published in English in peer-reviewed journals through 2014. Twenty-four studies from 34 articles were included. The number of parks observed per study ranged from 3 to 50. Most studies observed parks during one season. The number of days parks were observed ranged from 1 to 16, with 16 studies observing 5 or more days. All studies included at least one weekday and all but two included at least one weekend day. Parks were observed from 1 to 14 times/day, with most studies observing at least 4 times/day. All studies included both morning and afternoon observations, with one exception. There was a wide range of park users (mean 1.0 to 152.6 people/park/observation period), with typically more males than females visiting parks and older adults less than other age groups. Park user physical activity levels varied greatly across studies, with youths generally more active than adults and younger children more active than adolescents. SOPARC was adapted to numerous settings and these review results can be used to improve future studies using the tool, demonstrate ways to compare park data, and inform park promotions and programming
Chromosome aberrations in mammalian cells exposed to vitamin C and multiple vitamin pills
“Strange What Cosmopolites Music Makes of Us”: Classical Music, the Black Press, and Nora Douglas Holt's Black Feminist Audiotopia
Nicotine decreases agrin signaling and acetylcholine receptor clustering in C2C12 myotube culture
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