The Distribution of Atomic Hydrogen Around Two Irregular Galaxies

We present radio interferometric observations of two irregular galaxies that were candidates for having unusually extended HI emission. The galaxies, UGC 199 and DDO 26, otherwise appeared to be normal, low-luminosity systems with modest star-formation rates. To a detection limit of 2--3E19 /cm^2 at a resolution of about 50", however, the HI around neither galaxy is unusually extended compared to other irregulars. The HI around UGC 199 appears as a regular, symmetric distribution with regular rotation and a maximum rotation speed of about 80 km/s. By contrast, the HI around DDO 26 shows a concentration into two blobs with an arm in the outer parts to the northwest and some additional emission to the northwest of that. The kinematical major axis is approximately 75 deg from the HI and optical morphological axis which is unusual for Im galaxies. In addition the velocity field in the outer parts of the galaxy is messy and the velocity profiles at the two HI peaks are broad. We suggest that DDO 26 has been perturbed externally or may be two dwarfs in the process of merging.Comment: To be published in AJ, May 200

High Resolution H I Distributions and Multi-Wavelength Analyses of Magellanic Spirals NGC 4618 and NGC 4625

We present a detailed analysis of high resolution H I observations of the Magellanic spiral galaxies NGC 4618 and NGC 4625. While the H I disk of NGC 4625 is remarkably quiescent with a nearly uniform velocity dispersion and no evidence of H I holes, there is a dynamic interplay between star formation and the distribution of neutral hydrogen in NGC 4618. We calculate the critical density for widespread star formation in each galaxy and find that star formation proceeds even where the surface density of the atomic gas is well below the critical density necessary for global star formation. There are strong spatial correlations in NGC 4618 between UV emission, 1.4 GHz radio continuum emission, and peaks in the H I column density. Despite the apparent overlap of the outer disks of the two galaxies, we find that they are kinematically distinct, indicating that NGC 4618 and NGC 4625 are not interacting. The structure of NGC 4618 and, in particular, the nature of its outer ring, are highly suggestive of an interaction, but the timing and nature of such an interaction remain unclear

Determination of induction of Nur77 (NR4A1), Nor1 (NR4A3), and Nurr1 (NR4A2)

Previous data have implicated both neuronal activity and dopamine (DA) autoreceptor activation in the modulation of Nur receptor expression in dopamine neurons. Since dopamine receptor antagonists block the autoreceptors but also alter dopamine release and dopamine neuron activity, the mechanism responsible for gene expression is unclear. We hypothesized that blocking the stimulation of dopamine autoreceptors will be the mechanism that causes the induction of the nuclear receptor genes. To test this hypothesis, we treated 78 mice (1hr or 4hr incubation periods) with either a dopamine D2 receptor agonist (quinpirole), a D2 receptor antagonist (sulpiride or haloperidol) or γ-butyrolactone (GBL), a drug that inhibits dopamine neuron activity. HPLC and real time pCR was performed on each mouse to measure gene expression and neurochemical levels. We found that D2 receptor treatments induced Nur receptor expression levels and caused significant differences among neurochemical levels in the striatum and nucleus accumbens

CIOB Global Student Challenge – Evaluation of Virtual and International Competitions Aimed at the Construction Management Curriculum

Each year the Chartered Institute of Building hosts a six-week virtual competition called the Global Student Challenge. Three Cal Poly Construction Management students and myself competed in this competition. This challenge was an international competition that gave students the ability to manage their own construction company. This competition is the gateway to enhancing higher-level education through academic competitions. Students competitions, such as the ASC competitions, have been shown to improve academic success as Cal Poly’s Learn by Doing methodology is utilized. However, the largest flaw with academic competitions is the negative impact on classes outside of construction management. The purpose of this project is to incorporate more international and more virtual academic competitions into the Construction Management curriculum. A literary review as well as a survey was conducted to analyze student interest and assess the pros and cons of academic competitions, as well as the virtual and international applications. After a through investigation it is shown that students and professionals believe a virtual competition and an international competition will be beneficial not only to a student’s education but to their career paths as well

Tidally Induced Offset Disks in Magellanic Spiral Galaxies

Magellanic spiral galaxies are a class of one-armed systems that often exhibit an offset stellar bar, and are rarely found around massive spiral galaxies. Using a set of N-body and hydrodynamic simulations we consider a dwarf-dwarf galaxy interaction as the driving mechanism for the formation of this peculiar class of systems. We investigate here the relation between the dynamical, stellar and gaseous disk center and the bar. In all our simulations the bar center always coincides with the dynamical center, while the stellar disk becomes highly asymmetric during the encounter causing the photometric center of the Magellanic galaxy disk to become mismatched with both the bar and the dynamical center. The disk asymmetries persist for almost 2 Gyrs, the time that it takes for the disk to be re-centered with the bar, and well after the companion has passed. This explains the nature of the offset bar found in many Magellanic-type galaxies, including the Large Magellanic Cloud (LMC) and NGC 3906. In particular, these results, once applied to the LMC, suggest that the dynamical center should reside in the bar center instead of the HI center as previously assumed, pointing to a variation in the current estimate of the north component of the LMC proper motion.Comment: 12 pages, 8 figures, corrected for referee comment