1,796 research outputs found
Traffic Flow: An Approach towards Modeling the Right Lane Rule
We attempted to model and analyze the effect of the right hand rule for the 2014 COMAP Math Modeling Competition. In order to analyze the right hand rule we started with Greenshield’s macroscopic approach and modified it to simulate the effects of the right hand rule. By analyzing the resulting changes in the flow and density of the system we determined the performance of the rule in varying traffic densities. Next we looked at the performance by modeling traffic flow when the rule is strictly adhered to, as compared to an intermediate, where the rule is followed until the critical density is reached. In the intermediate model we show how traffic flow can be maximized if people no longer follow the right hand rule after the critical density
Mid Infrared Spectra of Radio Galaxies and Quasars
Spitzer Infrared Spectrograph (IRS) observations of 3C radio galaxies and
quasars shed new light on the nature of the central engines of AGN. Emission
from silicate dust obscuring the central engine can be used to estimate the
bolometric luminosity of an AGN. Emission lines from ions such as O IV and Ne V
give another indication of the presence or lack of a hidden source of far-UV
photons in the nucleus. Radio-loud AGN with relative-to-Eddington luminosity
ratios of L/L_Edd < 3E-3 do not appear to have broad optical emission lines,
though some do have strong silicate emission. Aromatic emission features from
star formation activity are common in low-luminosity radio galaxies. Strong
molecular hydrogen pure-rotational emission lines are also seen in some mid-IR
weak radio galaxies, caused by either merger shocks or jet shocks in the
interstellar medium.Comment: Conference proceedings to appear in "The Central Engine of Active
Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP
Why Try to Change Me Now? The Basis for the 2016 Indian Child Welfare Act
I. Introduction
II. Background ... A. Passage and Intent of the Indian Child Welfare Act ... B. 1979 Guidelines and Their Effects ... 1. The Bureau of Indian Affairs’s Position Against Binding Regulations ... 2. The Indian Child Welfare Act’s Inconsistent Application Throughout the States ... C. The Bureau of Indian Affairs’s Change in Position and 2016 Promulgated Regulations
III. Analysis ... A. Tenth Amendment and Federalism Concerns ... B. Applicability of Chevron Defense ... C. Mississippi Bank of Choctaw Indians v. Holyfield … D. Timeliness ... 1. Brock and Barnhart ... 2. Legislative History ... 3. Public Policy ... E. Other Consequences of Delayed Action
IV. Conclusio
Alliaria petiolata (M.Bieb.) Cavara & Grande [Brassicaceae], an Invasive Herb in the Southern Ozark Plateaus: A Comparison of Species Composition and Richness, Soil Properties, and Earthworm Composition and Biomass in Invaded Versus Non-Invaded Sites
Invasive species are widely recognized as organisms that severely alter ecosystem processes in the habitats to which they are introduced. Alliaria petiolata is one of the most important invasive plants in forests of the northern United States. This study examined the geographic distribution of the plant in the southern Ozarks, as well as the effect that it may be having on natural processes within forests of the region by comparing plant species richness, plant cover, and soil properties in invaded and non-invaded plots. It was found that A. petiolata is not significantly altering species richness, cover, or soil properties in the region, and this may be due to the fact that infestations were only about 1% as dense as those in forests of the northern United States. Populations of A. petiolata in the Ozarks were sampled to determine survivorship, fecundity, and preferred habitat types of plants in these forests. This study found that overall mortality of A. petiolata was 93.0%, with the highest mortality occurring between seedling and rosette stage (92.3%). Winters in this region are sufficiently mild enough to allow for very low rosette mortality (0.7%) compared with forests in the northern United States, and this may point to future infestations that rival those in northern forests. Adult plants averaged 70.3 ± 20.5 cm tall and produced an average of 2.1 ± 1.7 stems, 33.5 ± 45.6 siliques and 406 ± 670.8 seeds. Populations sampled in floodplain forests had higher densities of plants at each life stage, experienced higher overall survival rates, and were more reproductively successful than populations sampled in upland forests. Plots were also sampled to determine whether or not non-native earthworms were correlated with increased A. petiolata density. Although earthworm biomass and leaf litter cover were not significantly different between invaded and non-invaded plots, overall non-native earthworm biomass comprised 95.5% of the total biomass sampled, which indicates that non-native earthworms may be displacing native earthworms in disturbed floodplain and upland hardwood forests of the southern Ozarks
Collagen Binding Proteins Derived from the Embryonic Fibroblast Cell Surface Recognize Arginine-Glycine-Aspartic Acid
Several cell surface proteins (Mr = 120,000, 90,000, 63,000 and 47,000) apparently integral to embryonic fibroblast plasma membranes were extracted with detergent and isolated by collagen affinity chromatography. Certain of these proteins (Mr = 120,000, 90,000, and 47,000) were specifically eluted from collagen affinity columns by synthetic peptides containing the amino acid sequence arginyl-glycyl-aspartic acid (RGD). These data show that a number of collagen binding proteins exist on the embryonic fibroblast cell surface. Some of the proteins may be collagen receptors binding to RGD sequences in the collagen molecule while at least one of the proteins (Mr = 63,000) recognizes features other than RGD
The Spitzer View of FR I Radio Galaxies: On the Origin of the Nuclear Mid-Infrared Continuum
We present Spitzer mid-infrared (MIR) spectra of 25 FR I radio galaxies and investigate the nature of their MIR continuum emission. MIR spectra of star-forming galaxies and quiescent elliptical galaxies are used to identify host galaxy contributions while radio/optical core data are used to isolate the nuclear nonthermal emission. Out of the 15 sources with detected optical compact cores, four sources are dominated by emission related to the host galaxy. Another four sources show signs of warm, nuclear dust emission: 3C15, 3C84, 3C270, and NGC 6251. It is likely that these warm dust sources result from hidden active galactic nuclei of optical spectral type 1. The MIR spectra of seven sources are dominated by synchrotron emission, with no significant component of nuclear dust emission. In parabolic spectral energy distribution fits of the nonthermal cores FR Is tend to have lower peak frequencies and stronger curvature than blazars. This is roughly consistent with the common picture in which the core emission in FR Is is less strongly beamed than in blazars
A study on the influence of peripheral or central administration of ondansetron on stress-induced gastric ulceration
published_or_final_versio
High-ionization mid-infrared lines as black hole mass and bolometric luminosity indicators in active galactic nuclei
We present relations of the black hole mass and the optical luminosity with
the velocity dispersion and the luminosity of the [Ne V] and the [O IV]
high-ionization lines in the mid-infrared (MIR) for 28 reverberation-mapped
active galactic nuclei. We used high-resolution Spitzer Infrared Spectrograph
and Infrared Space Observatory Short Wavelength Spectrometer data to fit the
profiles of these MIR emission lines that originate from the narrow-line region
of the nucleus. We find that the lines are often resolved and that the velocity
dispersion of [Ne V] and [O IV] follows a relation similar to that between the
black hole mass and the bulge stellar velocity dispersion found for local
galaxies. The luminosity of the [Ne V] and the [O IV] lines in these sources is
correlated with that of the optical 5100A continuum and with the black hole
mass. Our results provide a means to derive black hole properties in various
types of active galactic nuclei, including highly obscured systems.Comment: accepted for publication in ApJ
Laminin Potentiates Differentiation of PCC4uva Embryonal Carcinoma into Neurons
The embryonal carcinoma PCC4uva differentiates into neurons in response to treatment with retinoic acid and dbcAMP. We used this in vitro model system to study the effects of laminin on early neural differentiation. Laminin substrata markedly potentiate neural differentiation of retinoic acid and dbcAMP-treated cultures. Only laminin induced more rapid neural cell body clustering, neurite growth and neurite fasciculation as compared to type IV collagen, type I collagen, and fibronectin substrata. Exogenous laminin substrata promoted greater cell attachment, cellular spreading and growth to confluence than type IV collagen, type I collagen, fibronectin and glass substrata. Laminin-induced effects were inhibited by addition of laminin antibodies or the synthetic laminin-derived peptide Ile-Gly-Ser-Arg-NH2 (YIGSR-NH2). Treatment with YIGSR-NH2 also inhibited neural differentiation in the absence of exogenous laminin substrata, whereas synthetic peptides containing the RGD sequence and a control peptide YIGSK-NH2 showed no inhibitory effects. These results are consistent with the hypothesis that specific interactions between an early differentiating cell population(s) and extracellular laminin are required during neural differentiation
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