Biomodeling of pancreatic tumor mass.

Pancreatic adenocarcinoma is the fourth leading cause of cancer death in the United States. It is identified by its rapid, invasive progression with a profound resistance to treatments such as chemotherapy. Unfortunately, there is a lack of information on how to effectively inhibit and control the rapid growth of pancreatic tumors, as well as limited information for diagnostics. With current methods, pancreatic cancer will continue to prevail as a leading cause of cancer death. We propose to study the complexity of pancreatic tumors with a systematic and analytical approach. Cancer is an abnormal growth of tissue caused by uncontrolled cell division. Observing the growth of these cells would prove to have a good basis to monitor the growth of a tumor. Here we create a 3-D simulation of tumor growth through mathematical modeling, using data from pancreatic cells grown in vitro. Using 3-D models will help to understand pancreatic tumors at cellular and molecular levels. The project aims to observe realistic growth of the tumor, accomplished from growing tumor cells on a monolayer in order to find parameters for our 3D mathematical model. This method will prove more beneficial than testing only on a monolayer cell line. Although cell death and the toxicity of drug dosage can be tested using a cell monolayer alone, it does not meet the demands of testing drug delivery in a realistic tumor environment that the mathematical model would provide. The monolayer lacks the dimensions that the drug would have to travel if it were delivered to a real in vivo tumor. A possible continuation of this project in the future could be to utilize the mathematical based approach to predict optimal therapy for the pancreatic tumor in order to develop models that can better test patient care for tumors. Computer modeling, another stepping stone through mathematical modeling, will possibly lead to testing the toxic effects of drugs on a 3-D model through computer modeling will aid in understanding the delivery of drugs throughout the tumor in vivo

Motivations of Civil War Soldiers from Western New York

The American Civil War was the bloodiest conflict in the history of the United States. Over 620,000 lives were lost during this war. Yet, what motivated volunteer soldiers to fight so valiantly for so long is the focus of this paper. After reading over 100 individual diaries and letters from volunteer Civil War soldiers from Western New York, who fought on the Union side, I have concluded that certain motivations influenced soldiers more than others to keep fighting. Motivations of the thrill of combat, adventure, and hatred of the enemy served as the initial motivations for Western New York Civil War soldiers to go to war. While the motivations of duty, honor, patriotism, and ideology/religion functioned as both initial and sustaining motivations, the impulses of courage, self-respect and group cohesion were the main sources of combat motivation. This paper focuses on volunteer soldiers specifically from Western New York and looks at their initial motivations, along with their sustaining motivations. I focused my research specifically on Western New York because of its heterogeneous population makeup and the large role it played with the Underground Railroad due to its close proximity to Canada. This paper keeps in mind the time period in which the Civil War took place and society’s values in antebellum America. This paper also looks at the technological innovations which took place during the Civil War and how they changed the battlefield for the volunteer soldier. This paper does not ignore the draft which occurred later in the war, and the draft riots associated with it. Finally, it looks at how the soldiers survived after the war was over

Exploring Infrared Properties of Giant Low Surface Brightness Galaxies

Abridged: We present analysis of Spitzer Space Telescope observations of the three low surface brightness (LSB) optical giant galaxies Malin 1, UGC 6614 and UGC 9024. Mid- and far-infrared morphology, spectral energy distributions, and integrated colors are used to derive the dust mass, dust-to-gas mass ratio, total infrared luminosity, and star formation rate (SFR). The 8 micron images indicate that polycyclic aromatic hydrocarbon molecules are present in the central regions of all three metal-poor LSB galaxies. The diffuse optical disks of Malin 1 and UGC 9024 remain undetected at mid- and far-infrared wavelengths. The dustiest of the three LSB galaxies, UGC 6614, has infrared morphology that varies significantly with wavelength. The 8 and 24 micron emission is co-spatial with H\alpha emission previously observed in the outer ring of UGC 6614. The estimated dust-to-gas ratios, from less than 10^{-3} to 10^{-2}, support previous indications that the LSB galaxies are relatively dust poor compared to the HSB galaxies. The total infrared luminosities are approximately 1/3 to 1/2 the blue band luminosities, suggesting that old stellar populations are the primary source of dust heating in these LSB objects. The SFR estimated from the infrared data ranges ~0.01-0.88 M_sun yr^{-1}, consistent with results from optical studies.Comment: Accepted in ApJ (2007, July 20 issue), 34 pages, 10 postscript figures, 2 table

Power-recycled weak-value-based metrology

We improve the precision of the interferometric weak-value-based beam deflection measurement by introducing a power recycling mirror, creating a resonant cavity. This results in \emph{all} the light exiting to the detector with a large deflection, thus eliminating the inefficiency of the rare postselection. The signal-to-noise ratio of the deflection is itself magnified by the weak value. We discuss ways to realize this proposal, using a transverse beam filter and different cavity designs.Comment: 5 pages, 1 figur

Star Formation Histories of Nearby Elliptical Galaxies. II. Merger Remnant Sample

This work presents high $S/N$ spectroscopic observations of a sample of six suspected merger remnants, selected primarily on the basis of H{\sc i} tidal debris detections. Single stellar population analysis of these galaxies indicates that their ages, metallicities, and $\alpha$-enhancement ratios are consistent with those of a representative sample of nearby elliptical galaxies. The expected stellar population of a recent merger remnant, young age combined with low [$\alpha$/Fe], is not seen in any H{\sc i}-selected galaxy. However, one galaxy (NGC~2534), is found to deviate from the $Z$-plane in the sense expected for a merger remnant. Another galaxy (NGC~7332), selected by other criteria, best matches the merger remnant expectations.Comment: 12 pages, 10 figures, accepted by A

Resolving the Controversy Over the Core Radius of 47 Tucanae (NGC 104)

This paper investigates the discrepancy between recent measurements of the density profile of the globular cluster 47 Tuc that have used HST data sets. Guhathakurta et al. (1992) used pre-refurbishment WFPC1 V-band images to derive r_c = 23" +/- 2". Calzetti et al. (1993) suggested that the density profile is a superposition of two King profiles (r_c = 8" and r_c = 25") based on U-band FOC images. De Marchi et al. (1996) used deep WFPC1 U-band images to derive r_c = 12" +/- 2". Differences in the adopted cluster centers are not the cause of the discrepancy. Our independent analysis of the data used by De Marchi et al. reaches the following conclusions: (1) De Marchi et al.'s r_c ~ 12" value is spuriously low, a result of radially-varying bias in the star counts in a magnitude limited sample -- photometric errors and a steeply rising stellar luminosity function cause more stars to scatter across the limiting magnitude into the sample than out of it, especially near the cluster center where crowding effects are most severe. (2) Changing the limiting magnitude to the main sequence turnoff, away from the steep part of the luminosity function, partially alleviates the problem and results in r_c = 18". (3) Combining such a limiting magnitude with accurate photometry derived from PSF fitting, instead of the less accurate aperture photometry employed by De Marchi et al., results in a reliable measurement of the density profile which is well fit by r_c = 22" +/- 2". Archival WFPC2 data are used to derive a star list with a higher degree of completeness, greater photometric accuracy, and wider areal coverage than the WFPC1 and FOC data sets; the WFPC2-based density profile supports the above conclusions, yielding r_c = 24" +/- 1.9".Comment: 22 pages, 5 figures, 1 table; accepted for publication in PASP; see http://www.ucolick.org/~raja/hgg.tar.gz for full-resolution figure

Evaluation of Operation IceBridge quick-look snow depth estimates on sea ice

We evaluate Operation IceBridge (OIB) ‘quick-look’ (QL) snow depth on sea ice retrievals using in situ measurements taken over immobile first-year ice (FYI) and multi-year ice (MYI) during March of 2014. Good agreement was found over undeformed FYI (-4.5 cm mean bias) with reduced agreement over deformed FYI (-6.6 cm mean bias). Over MYI, the mean bias was -5.7 cm but 54% of retrievals were discarded by the OIB retrieval process as compared to only 10% over FYI. Footprint scale analysis revealed a root mean square error (RMSE) of 6.2 cm over undeformed FYI with RMSE of 10.5 cm and 17.5 cm in the more complex deformed FYI and MYI environments. Correlation analysis was used to demonstrate contrasting retrieval uncertainty associated with spatial aggregation and ice surface roughness

Exclusion of Stellar Companions to Exoplanet Host Stars

Given the frequency of stellar multiplicity in the solar neighborhood, it is important to study the impacts this can have on exoplanet properties and orbital dynamics. There have been numerous imaging survey projects established to detect possible low-mass stellar companions to exoplanet host stars. Here we provide the results from a systematic speckle imaging survey of known exoplanet host stars. In total, 71 stars were observed at 692~nm and 880~nm bands using the Differential Speckle Survey Instrument (DSSI) at the Gemini-North Observatory. Our results show that all but 2 of the stars included in this sample have no evidence of stellar companions with luminosities down to the detection and projected separation limits of our instrumentation. The mass-luminosity relationship is used to estimate the maximum mass a stellar companion can have without being detected. These results are used to discuss the potential for further radial velocity follow-up and interpretation of companion signals.Comment: 11 pages, 4 figures, 3 tables, accepted for publication in A