EzGal: A Flexible Interface for Stellar Population Synthesis Models

We present EzGal, a flexible python program designed to easily generate observable parameters (magnitudes, colors, mass-to-light ratios) for any stellar population synthesis (SPS) model. As has been demonstrated by various authors, the choice of input SPS models can be a significant source of systematic uncertainty. A key strength of EzGal is that it enables simple, direct comparison of different models sets. EzGal is also capable of generating composite stellar population models (CSPs) and can interpolate between metallicities for a given model set. We have created a web interface to run EzGal and generate observables for a variety of star formation histories and model sets. We make many commonly used SPS models available from this interface; the BC03 models, an updated version of these models, the Maraston models, the BaSTI models, and finally the FSPS models. We use EzGal to compare magnitude predictions for the model sets as a function of wavelength, age, metallicity, and star formation history. We recover the well-known result that the models agree best in the optical for old, solar metallicity models, with differences at the ~0.1 magnitude level. The most problematic regime for SPS modeling is for young ages (7500 Angstroms) where scatter between models can vary from 0.3 mags (Sloan i) to 0.7 mags (Ks). We find that these differences are best understood as general uncertainties in SPS modeling. Finally we explore a more physically motivated example by generating CSPs with a star formation history matching the global star formation history of the universe. We demonstrate that the wavelength and age dependence of SPS model uncertainty translates into a redshift dependent model uncertainty, highlighting the importance of a quantitative understanding of model differences when comparing observations to models as a function of redshift.Comment: 10 pages, 5 figures, accepted for publication in PAS

Beyond Shelby County

In the aftermath of the 2016 elections there is ample data to examine trends in voter turnout across the states. This election cycle also provided the first national election in fifty years without the full protections of the Voting Rights Act (VRA). Previously covered states and jurisdictions were no longer required to obtain preclearance in the enactment of voting legislation. This thesis will seek to answer which interest was being served by the new voting laws in several states and whether the gutting of the Voting Rights Act by the U.S. Supreme Court had an impact on voter turnout. It begins with an examination of the Supreme Court\u27s decision in Shelby County v. Holder (2013) and the restrictive voting legislation enforced for the first time in the 2016 elections. Next, voter identification laws will be discussed as a restrictive form of legislation that has had some impact on voter turnout in states. Subsequently, popular vote totals from the 2012 elections will be compared with the 2016 elections to determine whether turnout increased or decreased in certain states. This will be followed by a legal analysis of the Court\u27s decisions to examine how the Court reached its result. Finally, legislative alternatives to the VRA will be examined as this thesis seeks to answer what effect the weakening of the VRA by the U.S. Supreme Court had on turnout

A Test of Photometric Redshifts for X-ray Selected Sources

We test the effectiveness of photometric redshifts based upon galaxy spectral template fitting for X-ray luminous objects, using a sample of 65 sources detected by Chandra in the field of the Caltech Faint Galaxy Redshift Survey (CFGRS). We find that sources with quasar-dominated spectra (for which galaxy spectral templates are not appropriate) are easily identified, and that photometric redshifts are robust for the rest of the sources in our sample. Specifically, for the 59 sources that are not quasar-dominated at optical wavelengths, we find that the photometric redshift estimates have scatter comparable to the field galaxy population in this region. There is no evidence for a trend of increasing dispersion with X-ray luminosity over the range L_X = 10^39 - 5x10^43 erg/s, nor is there a trend with the ratio of X-ray to optical flux, f_X/f_R. The practical implication of this work is that photometric redshifts should be robust for the majority (~90%) of the X-ray sources down to f_X ~ 10^-16 erg/s/cm^2 that have optical counterparts brighter than R ~ 24. Furthermore, the same photometry can be easily used to identify the sources for which the photometric redshifts are likely to fail. Photometric redshift estimation can thus be utilized as an efficient tool in analyzing the statistical properties of upcoming large Chandra and XMM-Newton data sets and identifying interesting subsamples for further study.Comment: To appear in ApJ (6 pages, 6 figures). Replaced with accepted versio

An Educational Module on the Benefits of Telehealth Assisted Preanesthetic Evaluations

Title An Educational Module on the Benefits of Telehealth Assisted Preanesthetic Evaluations Impact Statement Healthcare systems are always seeking new ways to increase efficiency, save on costs, and provide quality care for their patients. The use of telehealth in the preanesthesia setting is a tool that can help to further improve a healthcare system’s ability to achieve these goals. This project will be a step towards determining the support for and viability of telehealth utilization in the preanesthesia setting. Background/Purpose/Question Surgery cancellations are a significant problem with the potential for far-reaching consequences. Unexpected day-of-surgery cancellations can be costly to both the patient and the health care team. Telemedicine and telehealth are readily available tools for overcoming obstacles to accessing health care. Their use can improve patient outcomes, primarily by reducing the transportation time and costs and increasing the access to physicians. However, there is relatively little data on provider attitudes on the use of telemedicine to reduce cancellations and surgical delays. This project aims to answer: Among anesthesia providers (P), is an educational module designed to improve knowledge of the effectiveness of telehealth-assisted PAE (I), when compared to face-to-face preoperative assessment (C), effective in increasing provider knowledge (O) that leads to an improvement in the quality of patient care, the experience of the patient, its effect on staff, productivity, and cost-savings potential? Methods/Evidence Search Using the keywords listed under “Eligibility Criteria,” a search was conducted on CINAHL. Non-English, non-peer-reviewed articles were eliminated from the search, as well as articles older than 10 years. The same steps were taken with PubMed and Google Scholar. A total of 152 articles were found as potential evidence sources. Sources meeting criteria based on title were 44. Sources meeting criteria based on abstract were 13. Finally, sources meeting criteria based on full text were 8: a systematic literature review, a prospective randomized trial, a case-controlled study, a quasi-experimental study, a retrospective study, 2 descriptive studies, and a mixed methods approach. A total of 7 of the studies were performed in the United Sates while 1 was done in Australia. Synthesis of Literature/Results/Discussion A systematic literature review was conducted by Schoen and Prater. The results of their systematic review found that PAE can be successfully performed using telehealth and that patients also reported satisfaction with utilization of telehealth when performing PAE. For this project, the pre-test and post-test assessed if the educational module enhanced the participants attitude and perception of the use of telehealth during the PAE. The results show that after an educational module was shown, perception of the technology improved. Future research should focus on creating experiments with larger sample sizes and implementing the technology to see what real-world benefits the technology can offer. Conclusions/Recommendations for Practice 4 Telehealth is an increasingly relevant topic in the healthcare industry. It can provide many benefits to both the provider and the consumer. The project shows that presenting the topic and educating providers about the topic can make them more open to using the technology in their practice. Information gained from this project can be used to determine the feasibility of implementing this technology at health care facility where anesthesia providers practice

Distant Galaxy Clusters Identified From Optical Background Fluctuations

We present the first high redshift (0.3 < z < 1.1) galaxy clusters found by systematically identifying optical low surface brightness fluctuations in the background sky. Using spectra obtained with the Keck telescope and I-band images from the Palomar 1.5m telescope, we conclude that at least eight of the ten candidates examined are high redshift galaxy clusters. The identification of such clusters from low surface brightness fluctuations provides a complementary alternative to classic selection methods based on overdensities of resolved galaxies, and enables us to search efficiently for rich high redshift clusters over large areas of the sky. The detections described here are the first in a survey that covers a total of nearly 140 sq. degrees of the sky and should yield, if these preliminary results are representative, over 300 such clusters.Comment: Submitted to ApJ