IDENTIFYING RISK FACTORS ASSOCIATED WITH CARDIOVASCULAR DISEASE RISK IN LESBIANS

Cardiovascular disease (CVD) is the leading cause of female deaths in the United States (1). While women, in general, are at risk for CVD, current research indicates that sexual minority women (i.e. lesbians and bisexual women [SMW]) may be at greater risk for CVD than heterosexual women. This heightened risk potentially stems from an increased prevalence of traditional CVD risk factors in SMW, creating health disparities between SMW and their heterosexual counterparts (2). Further research into this high-risk population is needed, in order to minimize these disparities. The purpose of this study was to establish differences in the prevalence of modifiable CVD risk factors among lesbians and heterosexual women and compare their risks for coronary heart disease. This study also sought to identify best practices for obtaining higher rates of sexual orientation (SO) disclosure in questionnaire settings. Data collected through the Houston HeartReach Registry from 2013-2017 was used for the creation of a lesbian cohort. A cohort of heterosexual women was aggregated from the 2015-2016 National Health and Nutrition Examination Surveys. Both cohorts contained information on sociodemographic data and traditional CVD risk factors. A 10-year risk score for developing coronary heart disease was calculated for all women and compared by SO. Differences in the prevalence of traditional cardiovascular disease risk factors were also examined by SO. Lesbians were more likely to be current or ever smokers, to be depressed or have hypertension, to have an education level past high school, and to earn less income than their heterosexual counterparts. On average, lesbian participants had a 0.60% (95% confidence interval [CI] = -0.25%, 1.44%) greater chance of developing coronary heart disease over the next ten years than their heterosexual counterparts, but this difference was not significant (p = 0.167). Neither income, glucose, family history of cardiovascular disease, or depression accounted for this difference, but education and body mass index (BMI) partially intensified this difference. Lesbians have an increased prevalence of various CVD risk factors compared to their heterosexual counterparts, but future research is needed to fully understand the causes of these increased risk factors and their effect on CVD risk. With lesbians comprising a uniquely high-risk subgroup for CVD, attention must be paid to their CVD risk profile. The identification of CVD risk factors unique to and/or heightened in lesbians will allow for more targeted interventions that can lead to a reduction in disparities of CVD risk for lesbians and reduce the morbidity of CVD in women overall. A literature review of PubMed, conducted as a part of this thesis, indicates that future epidemiologic studies working with SMW should create an LGBT-welcoming environment, use accepting and inclusive language, and demonstrate a knowledge of lesbian-specific health at recruiting events and in questionnaires, in order to facilitate SO disclosure and increase the likelihood of successful recruitment

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations

Extraction of the Muon Signals Recorded with the Surface Detector of the Pierre Auger Observatory Using Recurrent Neural Networks

We present a method based on the use of Recurrent Neural Networks to extract the muon component from the time traces registered with water-Cherenkov detector (WCD) stations of the Surface Detector of the Pierre Auger Observatory. The design of the WCDs does not allow to separate the contribution of muons to the time traces obtained from the WCDs from those of photons, electrons and positrons for all events. Separating the muon and electromagnetic components is crucial for the determination of the nature of the primary cosmic rays and properties of the hadronic interactions at ultra-high energies. We trained a neural network to extract the muon and the electromagnetic components from the WCD traces using a large set of simulated air showers, with around 450 000 simulated events. For training and evaluating the performance of the neural network, simulated events with energies between 1018.5, eV and 1020 eV and zenith angles below 60 degrees were used. We also study the performance of this method on experimental data of the Pierre Auger Observatory and show that our predicted muon lateral distributions agree with the parameterizations obtained by the AGASA collaboration

A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (X$_{max}$) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of X$_{max}$ with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy