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Ice thickness regulates heat flux in permanently ice-covered lakes
No full textThe permanently ice-covered lakes of Taylor Valley, Antarctica, are rare ecosystems where permanent ice cover and year-round vertically stable water columns provide critical redox zones for cold-adapted microorganisms. Using 30 yr of limnological data from the McMurdo Dry Valleys Long-Term Ecological Research program, we assessed the water column heat flux of four permanently ice-covered lakes in the context of global lake ice decline and lake warming. Our study reveals that heat flux in Taylor Valley lakes is driven by ice cover dynamics, both annual changes in ice thickness as well as overall ice thickness. During periods of ice thinning, like those observed from 2020 to 2023, the lakes accumulate heat. Lake Fryxell, Lake Hoare, and West Lake Bonney have repeatedly cooled and warmed over our record, with only East Lake Bonney cooling due to lake level rise. Ice thickness is largely synchronous among the four lakes, with periods of asynchronicity likely caused by lake-specific changes in surface albedo driven by changes in optical properties of the ice covers and in-ice sediment dynamics
Examining Multi-Level Support-Related Factors Influencing School-Based Mental Health Services Across Various Types of U.S. Public High Schools
No full textYouth mental health is a global and national public health issue, with notable disparities in access to school-based mental health services (SBMHS; Kieling et al., 2024). This highlights the urgent need to identify supportive factors that can enhance service availability within educational settings. This cross-sectional, exploratory-descriptive study aimed to identify multi-level support-related factors (SRFs) at the student, school, and community levels that best predict SBMHS availability across different types of U.S. public high schools. The researcher conducted a secondary data analysis of a sample of 855 respondents who completed the 2017-18 School Survey on Crime and Safety. Various univariate, bivariate, and multivariate statistical analyses were conducted. The analysis characterized schools as low or high performing and examined how SRFs, such as student engagement (SE) activities, staff training (ST) opportunities, and parent/community (PC) involvement, vary across these categories. Binary logistic regression models estimated the associations between SRFs and the likelihood of schools offering comprehensive SBMHS, with separate models for low- and high-performing schools. Results identified several key multi-level SRFs as significant predictors of SBMHS availability, with distinct patterns across school types. These findings highlight the important role of microsystem and mesosystem influences in expanding mental health resources within schools, including behavioral modification, restorative circles, community integration programs, mental health interventions training, and juvenile justice and mental health agency involvement. Interestingly, safety training was negatively associated with SBMHS availability. The study provides implications for future social work research and social work practice in high school settings
An inexact ADMM for separable nonconvex and nonsmooth optimization
No full textAn inexact alternating direction method of multiplies (I-ADMM) with an expansion linesearch step was developed for solving a family of separable minimization problems subject to linear constraints, where the objective function is the sum of a smooth but possibly nonconvex function and a possibly nonsmooth nonconvex function. Global convergence and linear convergence rate of the I-ADMM were established under proper conditions while inexact relative error criterion was used for solving the subproblems. In addition, a unified proximal gradient (UPG) method with momentum acceleration was proposed for solving the smooth but possibly nonconvex subproblem. This UPG method guarantees global convergence and will automatically reduce to an optimal accelerated gradient method when the smooth function in the objective is convex. Our numerical experiments on solving nonconvex quadratic programming problems and sparse optimization problems from statistical learning show that the proposed I-ADMM is very effective compared with other state-of-the-art algorithms in the literature
Cartografía y paisaje en los nodos de producción, distribución y uso en la ruta de la grana cochinilla en la Nueva España a principios del siglo XVII
No full textAbstract
This article analyses the cartography and landscape produced in two nodes belonging to a global chain of grana cochinilla trade in New Spain at the beginning of the 17th century. The sources consulted from the 16th and 17th centuries are unpublished and contain evidence of production, local trade, and possible use of this precious pigment in an area slight studied on this subject, which was located between Izúcar and Acatlán. However, although at a global level there was an increase in the demand and distribution of grana cochinilla, at a local level, indigenous peoples who produced it faced various factors that endangered their production. We focus on studying two of them that are barely mentioned in historiography: the dynamics of land ownership and the introduction of livestock, since they affected their production and reconfigured the territory of the producing nodes through new economic sources. At the same time, the demand for maps or “pinturas” with legal validity before the Real Audiencia could have favored the use of this pigment by indigenous painters specialized in the creation of pictographic documents. The results contribute to understanding the local socio-environmental context of grana cochinilla production in the context of the global panorama.
Resumen
En este artículo se analiza la cartografía y paisaje de dos nodos pertenecientes a una cadena global de comercio de grana cochinilla a principios del siglo XVII en la Nueva España. Las fuentes consultadas de los siglos XVI y XVII son inéditas y contienen indicios de producción, comercio local y posible uso de tan preciado pigmento en un área poco estudiada en este tema, que estaba ubicada entre Izúcar y Acatlán. No obstante, aunque a nivel global existía un aumento en la demanda y distribución de grana, en el ámbito local, pueblos indígenas que la elaboraban se enfrentaban a diversos factores que pusieron en peligro su producción. Nos enfocamos en estudiar dos de ellos apenas mencionados en la historiografía: la dinámica de tenencia de la tierra y la introducción de ganadería, ya que afectaron su producción y reconfiguraron el territorio de los nodos productores a través de nuevas fuentes económicas. Paralelamente, la demanda de mapas o “pinturas” con validez jurídica ante la Real Audiencia pudo favorecer el uso de grana por parte de pintores indígenas especializados en la creación de documentos pictográficos. Los resultados contribuyen a comprender el contexto socioambiental local de la producción de cochinilla frente al panorama global
The Nature of Optical Afterglows without Gamma-Ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling
Full text linkIn the past few years, the improved sensitivity and cadence of wide-field optical surveys have enabled the discovery of several afterglows without associated detected gamma-ray bursts (GRBs). We present the identification, observations, and multiwavelength modeling of a recent such afterglow (AT 2023lcr), and model three literature events (AT 2020blt, AT 2021any, and AT 2021lfa) in a consistent fashion. For each event, we consider the following possibilities as to why a GRB was not observed: (1) the jet was off-axis; (2) the jet had a low initial Lorentz factor; and (3) the afterglow was the result of an on-axis classical GRB (on-axis jet with physical parameters typical of the GRB population), but the emission was undetected by gamma-ray satellites. We estimate all physical parameters using afterglowpy and Markov Chain Monte Carlo methods from emcee. We find that AT 2023lcr, AT 2020blt, and AT 2021any are consistent with on-axis classical GRBs, and AT 2021lfa is consistent with both on-axis low Lorentz factor (Γ0 ≈ 5-13) and off-axis (θobs = 2θjet) high Lorentz factor (Γ0 ≈ 100) jets
Extragalactic Magnetar Giant Flares: Population Implications, Rates, and Prospects for Gamma-Rays, Gravitational Waves, and Neutrinos
Full text linkMagnetar giant flares (MGFs) are the most energetic non-catastrophic transients known to originate from stellar objects. The first discovered events were nearby. In recent years, several extragalactic events have been identified, implying an extremely high volumetric rate. We show that future instruments with a sensitivity ≲5 × 10−9 erg cm−2 at ∼1 MeV will be dominated by extragalactic MGFs over short gamma-ray bursts (sGRBs). Clear discrimination of MGFs requires intrinsic GRB localization capability to identify host galaxies. As MGFs involve a release of a sizable fraction of the neutron star\u27s magnetic free energy reservoir in a single event, they provide us with invaluable tools for better understanding magnetar birth properties and the evolution of their magnetic fields. A major obstacle is to identify a (currently) small subpopulation of MGFs in a larger sample of more energetic and distant sGRBs. We develop the tools to analyze the properties of detected events and their occurrence rate relative to sGRBs. Even with the current (limited) number of events, we can constrain the initial internal magnetic field of a typical magnetar at formation to be B0 ≈ 4 × 1014-2 × 1015 G. Larger samples will constrain the distribution of birth fields. We also estimate the contribution of MGFs to the gravitational-wave (GW) stochastic background. Depending on the acceleration time of baryon-loaded ejecta involved in MGFs, their GW emission may reach beyond 10 kHz and, if so, will likely dominate over other conventional astrophysical sources in that frequency range
LSU General Catalog 2025-2026
Full text linkThe LSU General Catalog describes all undergraduate and graduate departments and programs with degree requirements and courses offered for each one. The LSU General Catalog includes information on registration and financial aid as well as academic services offered to all students
PRESERVATION AND TRANSFORMATION: REUTILIZING DECONSECRATED CHURCHES IN NEW ORLEANS - A CASE STUDY OF STS. PETER & PAUL CATHOLIC CHURCH
No full textThis thesis explores the complex issue of preserving the cultural heritage of Roman Catholic churches in the twenty-first century, with a focus on the transformation of Sts. Peter & Paul Catholic Church in the Marigny Neighborhood of New Orleans. The church, closed in 2001, has since been reimagined as the Hôtel Peter & Paul and The Elysian Bar. This study investigates the challenges and opportunities in the deconsecration and reutilization of sacred spaces, considering their role in the community, architectural preservation, and the broader identity of New Orleans.
This study will begin with the conceptual framework, exploring strategies for cultural preservation of New Orleans churches. Followed by a review of the literature on Catholic material culture focusing on the secular and sacred with a spatial concentration. Next, follows the methodology, the theoretical framework, this includes the historical analysis, which is the tracing of life, death, and rebirth. Then follows a brief history of the Roman Catholic Church architecture and the New Orleans Archdiocese, in modern times, including definitions of preservation objectives in the context of sacred space. Next, a results discussion follows that examines the evolution through preservation. This involves ethnographic insights that investigates the emotional allure after deconsecration. A large section of the thesis will be dedicated to the discussion of the case study of the Hôtel Peter & Paul. The concluding part of the discussion is on architectural space transformation that investigates evolving experiences over time. Ultimately the analysis and observations section reflects on what persists and transforms during the preservation process. The culmination of this study is a truncated speculative handbook, which outlines the crafting of a preservation guide
Ergosterol Peroxide Disrupts Triple-Negative Breast Cancer Mitochondrial Function and Inhibits Tumor Growth and Metastasis
No full textErgosterol peroxide (EP) triggers apoptosis pathways by inducing reactive oxygen species (ROS) in TNBC cell lines. Excess ROS production is associated with major damage to mitochondria. We hypothesized that EP may act through ROS-induced mitochondrial dysfunction. Therefore, we performed a series of assays that assessed mitochondrial membrane potential (MMP), cellular respiration, and glycolysis in TNBC models. Cardiomyocytes derived from human-induced pluripotent stem cells were chosen as a non-cancerous model because of their high mitochondrial content. Two in vivo TNBC models were used to quantify the effect of EP on tumor volume and metastases. EP reduced MMP and disrupted mitochondrial functions exclusively in TNBC cells. In vivo EP was effective in reducing tumor volume without affecting liver function. There was also a significant decrease in metastasis to the lung, liver, and cancer stem cells following treatment. These results suggest EP is a promising therapy for TNBC
Br-Li and stable isotopes to induce groundwater salinity in crystalline and detrital aquifers: Oriental Haouz Morocco
No full textStudy region: Paleozoic, Triassic and Quaternary lateral aquifers have been the subject of detailed geochemistry study, in Oriental Haouz, Morocco. Study method: Interpretations are based on the combination of major elements, Br, Li, and stable isotopes. In order to identify the origin of salinization, hydrochemical analysis were applied on forty groundwater samples, twenty of them are used for stable isotope measurement, three rivers, a sample from the natural spring in the south-western part and one rain water. New hydrochemical insights: High values of Li are considered with regard to micaschists and evaporite formations. This is roughly consistent with Lithium\u27s origin from saline dissolution. Cl/Br ratios show that the initial sedimentary rocks which give the present micaschists were relatively rich in evaporitic minerals and the beginning with of metamorphism during the hercynian orogeny, the major elements originally present in low-grade phases, would preserved in medium-grade phases such as evaporite minerals. Consequently, these minerals were easily liberated via alteration of alterated Paleozoic micaschist strata. NO32- does not only come from agricultural pollution but also from septic waste. Stable isotopes are segregated into two groups: Group1 coexists with high hydraulic parameters and is depleted of δ18O and δ2H; Group2 coexists with low hydraulic parameters, and is enriched with δ18O and δ2H. Thus, during precipitation events, waters infiltrate safely/sparingly, and evaporation did not/or occur following hydraulic parameters