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The Denali Ice Cores were collected from the summit of Begguya (Mt. Hunter), Denali National Park, Alaska in the summer of 2013. Sampling permits were granted by Denali National Park for the drilling and removal of the ice cores. Here, we use the Cameca SX100 at the University of Maine to examine tephra particles recovered from the ice cores. 

In 2013, two parallel ice cores (commonly referred to as the Denali Ice Cores) were drilled to bedrock on the summit plateau of Begguya, Alaska (62.93 N 151.083 W, 3912 m asl; also known as Mount Hunter). A robust chronology has been developed using a combination of techniques including annual layer counting, sulfate peaks (volcanics), radiocarbon dating and the 1963 atmospheric nuclear weapons testing horizon. Here, we employed tephrochronology practices to isolate and document the presence of the Lena Ash Layer and White River Ash east (WRAe) volcanic eruptions within the ice. We separated tephra from the meltwater and analyzed them using SEM-EDS and EPMA methodologies. The data are not immediately conclusive, and work is still ongoing to understand the findings. 

The Denali Ice Cores were collected from the summit of Begguya (Mt. Hunter), Denali National Park, Alaska in the summer of 2013. Sampling permits were granted by Denali National Park for the drilling and removal of the ice cores. Here, we use the Tescan II at the University of Maine to examine tephra particles recovered from the ice cores. 

Science instruction in elementary school provides a base for student understanding of the natural world, yet policies prioritizing mathematics and reading have marginalized science. In response, some teachers have enhanced their science instruction by introducing students to participatory science (PS) projects. Using data from a larger study that examines the development of educative support materials for two existing PS projects, this embedded mixed methods study focuses on teachers’ and students’ experiences learning outdoors. We compare teachers’ weekly log data, surveys, interviews, observations, and student focus groups to document teachers’ applications of PS in their science classrooms and outdoors. Teachers report benefits (e.g., purposeful science learning) and challenges (e.g., time constraints, testing pressure) of implementing outdoor PS projects. Teacher and student data document cognitive and affective benefits of students’ participation. Implications support the potential for PS projects that include schoolyard activities to supplement elementary science teaching and learning. 

Abstract Microbes play critical roles in dryland ecosystems, driving nutrient cycling, soil stability, and plant interactions. Despite their ecological importance, few studies have examined how microbial communities respond to vegetation changes in arid landscapes. In the northern extent of the Chihuahuan Desert, the encroachment of woody shrubs into grasslands has been occurring since the 1800s, largely driven by extensive livestock grazing and increased drought levels. In this study, we investigated how microbial communities respond to both biotic (i.e., vegetation) and abiotic (i.e., seasonality) factors, how they assemble in a changing landscape, and which taxa may be particularly responsive to shrub encroachment or even facilitating this transformation. We assessed microbial communities using soil surface samples across five distinct seasonal periods in a grassland-to-shrubland gradient in the Jornada Experimental Range in the Chihuahuan Desert through the use of phospholipid fatty-acid analysis and DNA metabarcoding techniques. Our findings reveal that bacterial and fungal biomass are significantly influenced by seasonal changes, with strong correlations to humidity and temperature fluctuations. We also found that fungal community assembly and diversity were highly impacted by vegetation whereas seasons were more impactful on bacteria. Our results support the idea that microbes may be playing a crucial role in facilitating the grassland-to-shrubland transition. Overall, our study highlights the complex interactions between microbial communities and biotic and abiotic factors in dryland systems. These findings are essential for understanding the future of dryland ecosystems undergoing shrub encroachment and provide a critical foundation for guiding restoration efforts, particularly those looking to incorporate microbial-mediated solutions. 

Maternal trauma influences infant and adult health outcomes and may impact future generations through epigenetic modifications such as DNA methylation (DNAm). Research in humans on the intergenerational epigenetic transmission of trauma effects is limited. In this study, we assessed DNAm signatures of war-related violence by comparing germline, prenatal, and direct exposures to violence across three generations of Syrian refugees. We compared families in which a pregnant grandmother versus a pregnant mother was exposed to violence and included a control group with no exposure to war. We collected buccal swab samples and survey data from mothers and 1-2 children in each of 48 families (n = 131 participants). Based on an epigenome-wide association study (EWAS), we identified differentially methylated regions (DMPs): 14 were associated with germline and 21 with direct exposure to violence. Most DMPs showed the same directionality in DNAm change across germline, prenatal, and direct exposures, suggesting a common epigenetic response to violence. Additionally, we identified epigenetic age acceleration in association with prenatal exposure to violence in children, highlighting the critical period of in utero development. This is the first report of an intergenerational epigenetic signature of violence, which has important implications for understanding the inheritance of trauma. 

The identification of fluorescent dyes in cultural heritage materials is challenging due to analyte fading, as well as sample scarcity and complexity. Here, we demonstrate a blinking-based methodology to identify single dye molecules in ink, relying solely on the dyes’ intrinsic fluorescence intermittency. Using widefield fluorescence microscopy, change point detection, and multinomial logistic regression, we define four quantitative determination factors that provide for positive and exclusive identification among three structurally similar rhodamine dyes. This approach is then applied to wet and dry commercial ballpoint ink samples and demonstrates the presence of rhodamine B, which is validated by bulk surface-enhanced Raman scattering (SERS) measurements. As compared to SERS, blinking-based identification yields exclusive and positive identification of rhodamine dyes with single-molecule sensitivity and without the need for plasmonic substrates. This minimally invasive and ultrasensitive method offers a powerful new tool for characterizing artists’ materials, opening opportunities for conservation and heritage science.