16 research outputs found
Age Analysis of NGC 2168 Cluster using BASE-9 Software
No full textThis research is an investigation into precision and accuracy of age determination in the open star cluster NGC 2168 using BASE-9 software. The project is divided into two parts with the first being the determination of the age of the entire cluster and the second being age determination of the individual stars within the cluster. Part one involves analyzing the collective properties of the cluster to derive its age. Part two involves assessing the age of individual stars within the selected star clusters using BASE-9 software. Through analysis of individual stars within the chosen clusters, we evaluated the reliability and validity of the age determinations obtained. This research project aims to contribute to the understanding of precision in age determination for both open star clusters and for individual stars by utilizing BASE-9 software by studying collective and individual age determinations of one open star cluster. This research will additionally contribute to advancing the knowledge of stellar evolution and star cluster properties
Core-collapse Supernovae Particle Physics Interactions within Simulations
No full textThis study investigates the role of specific particle physics interactions in simulations of core collapse supernovae, with a focus on understanding how varying levels of inclusion impact the accuracy of gravitational wave predictions and results of simulations. Different research groups often approach these simulations with varying degrees of complexity, cutting corners by omitting certain reactions or simplifying others. This project systematically evaluates the implications of these choices, comparing the particle physics interactions included, the dimensionality of the simulations, and the governing equations used. Our goal is to identify how these factors influence the precision of numerical simulations. By providing a comprehensive analysis of the advantages and drawbacks of including different particle interactions, we aim to improve the development of simulations used by instruments like LIGO (Laser Interferometer Gravitational Wave Observatory)
Asteroid Disruptions of the Datura Family
No full textTo research the Datura Family of asteroids, a prewritten dynamical IDL code was run to track the orbital decay of asteroid fragments released in an asteroid disruption. Different particle sizes were used to analyze the outputs of each size including the semi-major axis, eccentricity, and inclination in order to observe how certain particle sizes’ orbital elements evolve. Using a young asteroid family like the Datura family gives more insight into their original structure and formation because the time is closer to before the asteroid’s breakup. We use these models to constrain the parameters of the dust by comparing the conditions to infrared satellite data sets. The semi-major axis utilizes Poynting-Robertson drag while the eccentricity and inclination are related to the effects of Jupiter. But all of these orbital elements relate to the role of the radiative forces. This research is important to understand potential Earth hazards from space
The Core-Collapse Supernovae Particle Physics Interactions
No full textThis study investigates the role of specific particle physics interactions in simulations of core collapse supernovae, with a focus on understanding how varying levels of inclusion impact the accuracy of gravitational wave predictions and results of simulations. Different research groups often approach these simulations with varying degrees of complexity, cutting corners by omitting certain reactions or simplifying others. This project systematically evaluates the implications of these choices, comparing the particle physics interactions included, the dimensionality of the simulations, and the governing equations used. Our goal is to identify how these factors influence the precision of numerical simulations. By providing a comprehensive analysis of the advantages and drawbacks of including different particle interactions, we aim to improve the development of simulations used by instruments like LIGO (Laser Interferometer Gravitational Wave Observatory)
Orbital Evolution of the Datura Asteroid Family
No full textTo research the Datura Family of asteroids, we used an orbital evolution code to track the orbital decay of asteroid fragments released in an asteroid disruption. Different particle sizes of 10, 100, 500, 750, and 100 micrometers were tracked including the semi-major axis, eccentricity, and inclination in order to observe how certain particle sizes’ orbital elements evolve. Using a young asteroid family like the Datura family gives more insight into the parent asteroid structure and formation because the time is closer to before the asteroid’s breakup. We use these models to constrain the parameters of the dust by comparing the conditions to infrared satellite data sets. The particles evolve by the radiative forces like the Poynting-Robertson drag or solar wind. This research is important to understand potential Earth hazards of fast moving bodies while near Earth and cislunar space
Determining the Light Curve and 3D Shape of Asteroid Eunomia and Egeria Using Relative Photometry
No full textAsteroids are relics of our solar system’s early formation, preserving valuable information about planetary evolution. Understanding their rotational properties and surface features provides deeper insights into the dynamical and thermophysical processes that shape their evolution. This study aims to conduct photometric observations of two main-belt asteroids, Egeria and Eunomia, using the Embry-Riddle Aeronautical University 1-meter telescope. Observations will be conducted in the red band on February 28 and March 14, 2025, over five-hour sessions, capturing full rotational light curves for each asteroid. These data will be analyzed using MPO Canopus to generate 3D surface models through photometric inversion techniques. The results will provide insights into the effects of the Yarkovsky and YORP mechanisms on asteroid evolution and contribute to discussions on asteroid topography in public outreach initiatives. By improving our understanding of these celestial bodies, this research enhances broader studies on planetary formation and the evolution of small bodies in the solar system
Modeling Recent Asteroid Disruptions in the Solar System
No full textWe study the dynamical evolutions of the byproducts of recent asteroid disruptions to understand the population of small particles in near-Earth and cislunar space, which can post threats to spacecraft, satellites, and long-term lunar missions like Artemis. To assess this population, we track the dynamical evolution of dust particles created in a catastrophic asteroid disruption. Particle sizes ranging from a few microns to a few cm are modeled using a code that accounts for both the gravitational and radiative forces to accurately predict the orbital elementals of the dust particles in the Datura and Emilkowalski asteroid clusters. The resulting models show that the smaller particles decay into the inner solar system at a faster rate than their larger counterparts, meaning they are more likely to be dispersed throughout the solar system. Comparison of these models with infrared satellite observations allows us to put constraints on the size-distribution and amount of dust present which not only helps us contain the treat these particles may pose, but also understand the amount of surface regolith that was on the parent body asteroids
Detecting the influence of initial pioneers on succession at deep-sea vents
No full text© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 7 (2012): e50015, doi:10.1371/journal.pone.0050015.Deep-sea hydrothermal vents are subject to major disturbances that alter the physical and chemical environment and eradicate the resident faunal communities. Vent fields are isolated by uninhabitable deep seafloor, so recolonization via dispersal of planktonic larvae is critical for persistence of populations. We monitored colonization near 9°50′N on the East Pacific Rise following a catastrophic eruption in order to address questions of the relative contributions of pioneer colonists and environmental change to variation in species composition, and the role of pioneers at the disturbed site in altering community structure elsewhere in the region. Pioneer colonists included two gastropod species: Ctenopelta porifera, which was new to the vent field, and Lepetodrilus tevnianus, which had been rare before the eruption but persisted in high abundance afterward, delaying and possibly out-competing the ubiquitous pre-eruption congener L. elevatus. A decrease in abundance of C. porifera over time, and the arrival of later species, corresponded to a decrease in vent fluid flow and in the sulfide to temperature ratio. For some species these successional changes were likely due to habitat requirements, but other species persisted (L. tevnianus) or arrived (L. elevatus) in patterns unrelated to their habitat preferences. After two years, disturbed communities had started to resemble pre-eruption ones, but were lower in diversity. When compared to a prior (1991) eruption, the succession of foundation species (tubeworms and mussels) appeared to be delayed, even though habitat chemistry became similar to the pre-eruption state more quickly. Surprisingly, a nearby community that had not been disturbed by the eruption was invaded by the pioneers, possibly after they became established in the disturbed vents. These results indicate that the post-eruption arrival of species from remote locales had a strong and persistent effect on communities at both disturbed and undisturbed vents.The authors received funding from National Science Foundation grant OCE-0424953, WHOI Deep Ocean Exploration Institute, WHOI Summer Student Fellow program, Woods Hole Partnership in Education Program, IFREMER and CNRS, Fondation TOTAL Chair Extreme Marine Environment, Biodiversity and Global change
Comparative effectiveness of sodium-glucose cotransporter-2 inhibitors for new-onset gastric cancer and gastric diseases in patients with type 2 diabetes mellitus: a population-based cohort study
No full textTo compare the risks of gastric cancer and other gastric diseases in patients with type-2 diabetes mellitus (T2DM) exposed to sodium-glucose cotransporter 2 inhibitors (SGLT2I), dipeptidyl peptidase-4 inhibitors (DPP4I) or glucagon-like peptide-1 receptor agonists (GLP1a). This was a population-based cohort study of prospectively collected data on patients with T2DM prescribed SGLT2I, DPP4I or GLP1a between January 1st 2015 and December 31st 2020 from Hong Kong. The outcomes were new-onset gastric cancer, peptic ulcer (PU), acute gastritis, non-acute gastritis, and gastroesophageal reflux disease (GERD). Propensity score matching (1:1) using the nearest neighbour search was performed, and multivariable Cox regression was applied. A three-arm comparison between SGLT2I, DPP4I and GLP1a was conducted using propensity scores with inverse probability of treatment weighting. A total of 62,858 patients (median age: 62.2 years old [SD: 12.8]; 55.93% males; SGLT2I: n = 23,442; DPP4I: n = 39,416) were included. In the matched cohort, the incidence of gastric cancer was lower in SGLT2I (Incidence rate per 1000 person-year, IR: 0.32; 95% confidence interval, CI 0.23-0.43) than in DPP4I (IR per 1000 person-year: 1.22; CI 1.03-1.42) users. Multivariable Cox regression found that SGLT2I use was associated with lower risks of gastric cancer (HR 0.30; 95% CI 0.19-0.48), PU, acute gastritis, non-acute gastritis, and GERD (p < 0.05) compared to DPP4I use. In the three-arm analysis, GLP1a use was associated with higher risks of gastric cancer and GERD compared to SGLT2I use. The use of SGLT2I was associated with lower risks of new-onset gastric cancer, PU, acute gastritis, non-acute gastritis, and GERD after matching and adjustments compared to DPP4I use. SGLT2I use was associated with lower risks of GERD and gastric cancer compared to GLP1a use. [Abstract copyright: © 2024. The Author(s).
