Syracuse University
Syracuse University Research Facility and Collaborative EnvironmentNot a member yet
20376 research outputs found
Sort by
How Do Gender and Marital Status Impact High-Risk Polysubstance Use?
Get PDFDrug overdose deaths in the United States increasingly include the use of multiple drugs, known as polysubstance use. These include opioids, cocaine, methamphetamine, tranquilizers, and sedatives. Polysubstance use is considered high risk because it can cause dangerous synergistic effects and result in the ingestion of higher amounts of drugs. This brief summarizes findings from a study that used data from the National Survey on Drug Use and Health on U.S. adults from 2002 through 2019 to examine gender and marital status differences in high-risk polysubstance use among U.S. adults ages 18 and older. The authors find that polysubstance use is higher among men and marriage was more protective against polysubstance use for men than women
Two-Way Random Effects Model with Serial Correlation
Get PDFThis paper derives a feasible GLS estimator for a two-way error component model with serial correlation on both the time effects as well as the remainder disturbances. This estimator is based on two methods, one proposed by De Porres and Krishnakumar (2013) for deriving the spectral decomposition of a general error component structure and the other based on an inversion trick for the variance-covariance matrix of this model suggested by Skoglund and Karlsson (2001). While the last paper used maximum likelihood methods under the normality assumption, we use method of moments estimators following Baltagi and Li (1991) for the one-way error component model with serially correlated remainder disturbances and its extension by Brou et al. (2011) for the two-way model with serially correlated time effects as well as remainder disturbances. Monte Carlo simulations are performed to compare the performance of these two estimators as well as a bias correction version based on Nobach (2023). Our results find that the method based on the Skoglund and Karlsson (2001) inverse that is bias corrected a la Nobach (2023) performs the best in root mean square error (RMSE) as well as mean absolute percentage error (MAPE) and is recommended
Evaluating Subduction Zone Processes in Early Paleozoic Rocks of the Northern Appalachian Orogen
Get PDFThe study of rocks presently exposed at the surface in mountain ranges such as the Appalachian Mountains can offer insight into the evolution of orogenic and subduction zone processes over geologic time. To better understand the timing, conditions (i.e., pressure and temperature), and tectonic setting of mineral formation in former subduction settings, geologists conduct geochronology, geochemistry, and thermobarometry analyses on rocks and minerals in paleo-subduction zones. This dissertation contains three chapters that focus on serpentinization, hydrothermal alteration of mafic rocks during serpentinization (rodingitization), and high-pressure metamorphism that occurred in a subduction setting during the first phase of the Appalachian Orogeny. The first chapter uses Sm-Nd garnet geochronology to establish the timing of rodingitization and serpentinization in the northern Appalachian Mountains. The results show that multiple generations of garnet occur in serpentinite-hosted rodingites from Belvidere Mountain, Vermont. The oldest garnets formed in a subduction setting during the Taconic Orogeny (477.3±6.1 Ma) and provide a minimum estimate for the timing of serpentinization. The youngest garnets formed 70 My later in veins from low-temperature metasomatism and fluid circulation during the Salinic Orogeny (410.0±4.0 Ma). The first chapter demonstrates that Sm-Nd geochronology can successfully constrain the petrologic evolution of rodingites despite the effects of polymetamorphism and a ~70 My hiatus between different generations of garnet growth. The second chapter uses mineral and whole-rock geochemical analyses to constrain the fluid source and tectonic setting for serpentinization during the Taconic Orogeny. The serpentinites are enriched in slab-derived, fluid-mobile elements (e.g., As, Cs, and Sb) but depleted in elements such as U and Th, which are commonly enriched in seafloor serpentinites. Relict igneous olivine and spinel have high Cr/Al and Mg/Fe ratios, respectively, indicating mineral formation in a depleted mantle wedge. Together, these data suggest that serpentinization occurred in a mantle-wedge tectonic setting as opposed to an ocean-floor setting and that serpentinization was caused by slab-derived fluids. The results refine tectonic models for serpentinization during the Taconic Orogeny. The third chapter examines garnet-bearing pelitic schists in the northern Appalachian Mountains using trace-element thermobarometry (Ti-in-quartz, Zr-in-rutile) on inclusions in garnet and thermodynamic modelling to determine the conditions of garnet growth during subduction-zone metamorphism. The results show that meta-pelites from three localities in the Worcester Mountains preserve evidence for mineral growth at eclogite facies conditions up to 18 kbar and 695°C. This discovery adds to the growing number of studies suggesting that Taconic eclogite-facies metamorphism may be more widespread than previously recognized
Behavioral Self-regulation in Context: Timing, Types, and Changes of Material Hardship Across Childhood
No full textBehavioral self-regulation in childhood lays the foundation for lifelong adaptive functioning, including academic achievement, social relationships, and psychological well-being. While early poverty is consistently linked to worse behavioral self-regulation, less is known about how the timing, types, and changes in material hardship (i.e., daily experiences of deprivation), shape children’s development of behavioral self-regulation. This dissertation addresses these literature gaps through three interconnected studies that examine the dynamic association between material hardship and behavioral self-regulation across childhood, including (1) how early exposure to distinct patterns of material hardship in infancy shapes children’s behavioral self-regulation developmental trajectory from early to middle childhood; (2) how continuity and change in material hardship domains from infancy to preschool years relate to behavioral self-regulation in middle childhood; and (3) how transient fluctuation and persistent exposure to material hardship influences the development of behavioral self-regulation from early to middle childhood. In Study 1, we identified four distinct patterns of material hardship domains in infancy and found that material hardship class membership was associated with children’s behavioral self-regulation developmental trajectories from early to middle childhood. In Study 2, we uncovered four conjoint trajectories of material hardship across five domains during early childhood, varied by persistence, fluctuation, and intensity, with persistent and pervasive hardship class linked to the lowest levels of behavioral self-regulation in middle childhood. In Study 3, we found that transient fluctuations in hardship predicted contemporaneous declines in behavioral self-regulation, while persistent exposure to hardship affected initial levels of behavioral self-regulation. Together, this dissertation highlights the multifaceted and dynamic nature of material hardship and recognizes the malleability and adaptation of the development of behavioral self-regulation amidst economic adversity. The general discussion chapter of this dissertation offers critical implications for developmental theories, the design of targeted prevention and intervention programs, and future research directions