2,371 research outputs found

    Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

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    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures

    Risk and Protective Factors of Dementia Among Adults With Post-Traumatic Stress Disorder: A Systematic Review Protocol

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    INTRODUCTION: Post-traumatic stress disorder (PTSD) is associated with an increased risk of dementia. Individual epidemiological studies have controlled for several confounders of the relationship between PTSD and increased dementia risk, yet particular risk factors underlying this relationship have not been determined. This systematic review protocol aims to identify risk and protective factors of dementia among adults with PTSD. METHODS AND ANALYSIS: We will conduct an electronic search of the databases: PubMed, CINAHL, PsychINFO, The Cochrane Library, Scopus and ProQuest Dissertation and Theses Global. After screening the studies, quantitative synthesis will be performed, if possible. Otherwise, a narrative synthesis will be performed. We will include randomised controlled trials and other types of research evidence including longitudinal cohort studies. Strength of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations method. Examples of variables that will be extracted are: year of PTSD diagnosis, comorbid conditions, health behaviours, pharmacological treatments and year of mild cognitive impairment or dementia diagnosis. We developed this systematic review protocol according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 statement. ETHICS AND DISSEMINATION: The proposed study will not collect individual-level data and, therefore, does not require ethical approval. Results of this study will provide current evidence on risk and protective factors of dementia in adults with PTSD. Findings will be disseminated in peer-reviewed publications and conference presentations. PROSPERO REGISTRATION NUMBER: CRD42019128553

    Climate change influences foliar nutrition and metabolism of red maple (Acer rubrum) trees in a northern hardwood forest

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Blagden, M., Harrison, J. L., Minocha, R., Sanders-DeMott, R., Long, S., & Templer, P. H. Climate change influences foliar nutrition and metabolism of red maple (Acer rubrum) trees in a northern hardwood forest. Ecosphere, 13(2), (2022): e03859. https://doi.org/10.1002/ecs2.3859.Mean annual air temperatures are projected to increase, while the winter snowpack is expected to shrink in depth and duration for many mid- and high-latitude temperate forest ecosystems over the next several decades. Together, these changes will lead to warmer growing season soil temperatures and an increased frequency of soil freeze–thaw cycles (FTCs) in winter. We took advantage of the Climate Change Across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA, to determine how these changes in soil temperature affect foliar nitrogen (N) and carbon metabolism of red maple (Acer rubrum) trees in 2015 and 2017. Earlier work from this study revealed a similar increase in foliar N concentrations with growing season soil warming, with or without the occurrence of soil FTCs in winter. However, these changes in soil warming could differentially affect the availability of cellular nutrients, concentrations of primary and secondary metabolites, and the rates of photosynthesis that are all responsive to climate change. We found that foliar concentrations of phosphorus (P), potassium (K), N, spermine (a polyamine), amino acids (alanine, histidine, and phenylalanine), chlorophyll, carotenoids, sucrose, and rates of photosynthesis increased with growing season soil warming. Despite similar concentrations of foliar N with soil warming with and without soil FTCs in winter, winter soil FTCs affected other foliar metabolic responses. The combination of growing season soil warming and winter soil FTCs led to increased concentrations of two polyamines (putrescine and spermine) and amino acids (alanine, proline, aspartic acid, γ-aminobutyric acid, valine, leucine, and isoleucine). Treatment-specific metabolic changes indicated that while responses to growing season warming were more connected to their role as growth modulators, soil warming + FTC treatment-related effects revealed their dual role in growth and stress tolerance. Together, the results of this study demonstrate that growing season soil warming has multiple positive effects on foliar N and cellular metabolism in trees and that some of these foliar responses are further modified by the addition of stress from winter soil FTCs.This research was supported by an NSF Long Term Ecological Research (LTER) Grant to Hubbard Brook (NSF 1114804 and 1637685) and an NSF CAREER grant to PHT (NSF DEB1149929). RSD was supported by NSF DGE0947950, a Boston University (BU) Dean's Fellowship, and the BU Program in Biogeoscience. Jamie Harrison was supported by a BU Dean's Fellowship. Megan Blagden was supported by a BU Undergraduate Research Opportunity Program fellowship. This manuscript is a contribution to the Hubbard Brook Ecosystem Study. Hubbard Brook is part of the LTER network, which is supported by the NSF

    The Merging of a Coronal Dimming and the Southern Polar Coronal Hole

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    We report on the merging between the southern polar coronal hole and an adjacent coronal dimming induced by a coronal mass ejection on 2022 March 18, resulting in the merged region persisting for at least 72 hr. We use remote sensing data from multiple co-observing spacecraft to understand the physical processes during this merging event. The evolution of the merger is examined using Extreme-UltraViolet (EUV) images obtained from the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory and Extreme Ultraviolet Imager, which is on board the Solar Orbiter spacecraft. The plasma dynamics are quantified using spectroscopic data obtained from the EUV Imaging Spectrometer on board Hinode. The photospheric magnetograms from the Helioseismic and Magnetic Imager are used to derive the magnetic field properties. To our knowledge, this work is the first spectroscopical analysis of the merging of two open-field structures. We find that the coronal hole and the coronal dimming become indistinguishable after the merging. The upflow speeds inside the coronal dimming become more similar to that of a coronal hole, with a mixture of plasma upflows and downflows observable after the merging. The brightening of the bright points and the appearance of coronal jets inside the merged region further imply ongoing reconnection processes. We propose that component reconnection between the coronal hole and coronal dimming fields plays an important role during this merging event because the footpoint switching resulting from the reconnection allows the coronal dimming to intrude onto the boundary of the southern polar coronal hole

    Community Science’s Contributions to Fostering Relational Values to Overcome Coastal Ecosystems Challenges

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    This paper applies the emerging concept of ‘relational values’ – values people hold toward their relationships with nature and with each other – and brings attention to the role of community science in enhancing relational ecosystem values. We feature Gouldsboro Shore, Gulf of Maine Research Institute’s (GMRI) coastal flood monitoring, and river herring monitoring and restoration efforts as focal examples. Gouldsboro Shore activates community volunteers and high school students to support the management and resilience of their clam fishery in Gouldsboro, ME. GMRI’s flood monitoring provides a platform for coastal residents to report, monitor, and map coastal flooding in participating municipalities. In multiple towns, biologists and community members have worked together to restore aquatic habitat and connectivity to support river herring populations while also deepening their connection to their local ecosystems. In each case, community science contributed to enhancing both people-nature and people-people relationships in the community to overcome coastal ecosystem challenges. Coastal decision-makers need to move beyond the antiquated Millennium Ecosystem Assessment framework to recognize a wider set of values that people hold towards coastal and marine natural environments. Community science programs have the potential to foster relational values and activate sustainability-aligned values into action to overcome ecosystem and other societal challenges

    Novel Space Alters Theta and Gamma Synchrony Across the Longitudinal Axis of the Hippocampus.

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    Hippocampal theta (6–10 Hz) and gamma (25–50 Hz and 65–100 Hz) local field potentials (LFPs) reflect the dynamic synchronization evoked by inputs impinging upon hippocampal neurons. Novel experience is known to engage hippocampal physiology and promote successful encoding. Does novelty synchronize or desynchronize theta and/or gamma frequency inputs across the septotemporal (long) axis of the hippocampus (HPC)? The present study tested the hypothesis that a novel spatial environment would alter theta power and coherence across the long axis. We compared theta and gamma LFP signals at individual (power) and millimeter distant electrode pairs (coherence) within the dentate gyrus (DG) and CA1 region while rats navigated a runway (1) in a familiar environment, (2) with a modified path in the same environment and (3) in a novel space. Locomotion in novel space was related to increases in theta and gamma power at most CA1 and DG sites. The increase in theta and gamma power was concurrent with an increase in theta and gamma coherence across the long axis of CA1; however, there was a significant decrease in theta coherence across the long axis of the DG. These findings illustrate significant shifts in the synchrony of entorhinal, CA3 and/or neuromodulatory afferents conveying novel spatial information to the dendritic fields of CA1 and DG targets across the long axis of the HPC. This shift suggests that the entire theta/gamma-related input to the CA1 network, and likely output, receives and conveys a more coherent message in response to novel sensory experience. Such may contribute to the successful encoding of novel sensory experience

    Injury Risk and Noise Exposure in Firefighter Training Operations

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    Introduction: Firefighters have high rate of injuries and illnesses, as well as exposures to high levels of noise. This study explored the relationship between noise exposure and injury among firefighters. Methods: We recruited firefighters undergoing vehicle extrication and structural collapse emergency response training at a highly realistic training facility. Demographics, health status, body mass index (BMI), and history of serious injuries (i.e. injuries requiring first aid treatment, treatment in a medical clinic or office, or treatment at a hospital) were assessed at baseline, and daily activities, injury events, and near misses were assessed daily via surveys. Participants’ noise exposures were monitored for one 24-h period using noise dosimeters. We used a mixed-effects logistic regression model to estimate the odds of injury events and near misses associated with noise exposure as an independent variable. Results: Of 56 subjects, 20 (36%) reported that they had ever suffered a serious injury during firefighting activities, and 9 (16%) reported a serious injury within the past year. We estimated rates of 6.6 lifetime serious injuries per 100 FTE 16.1 serious injuries per 100 FTE within the past year. Our models indicated a significant increase in injury events and near misses among those with higher BMI, and as well as a dose–response relationship between near misses/injuries and increasing noise levels. Noise levels >90 dBA in the 30 min prior to time of injury or near miss were associated with substantially increased odds ratios for injury or near miss. Our models further indicated that perceived job demands were significantly associated with increased risk of injury or near miss. Conclusion: Our results suggest that noise exposures may need to be incorporated into injury prevention programs for firefighters to reduce injuries among this high-risk occupational group.This research was supported by a pilot project research training grant from the Center for Occupational Health and Safety Engineering (COHSE) at the University of Michigan, an Education and Research Center supported by training grant No. 2T42OH008455 from the Centers for Disease Control and Prevention/National Institute for Occupational Safety and Health.Ope

    Incorporating African American Veterans\u27 Success Stories for Hypertension Management: Developing a Behavioral Support Texting Protocol

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    BACKGROUND: Peer narratives engage listeners through personally relevant content and have been shown to promote lifestyle change and effective self-management among patients with hypertension. Incorporating key quotations from these stories into follow-up text messages is a novel way to continue the conversation, providing reinforcement of health behaviors in the patients\u27 daily lives. OBJECTIVE: In our previous work, we developed and tested videos in which African American Veterans shared stories of challenges and success strategies related to hypertension self-management. This study aims to describe our process for developing a text-messaging protocol intended for use after viewing videos that incorporate the voices of these Veterans. METHODS: We used a multistep process, transforming video-recorded story excerpts from 5 Veterans into 160-character texts. We then integrated these into comprehensive 6-month texting protocols. We began with an iterative review of story transcripts to identify vernacular features and key self-management concepts emphasized by each storyteller. We worked with 2 Veteran consultants who guided our narrative text message development in substantive ways, as we sought to craft culturally sensitive content for texts. Informed by Veteran input on timing and integration, supplementary educational and 2-way interactive assessment text messages were also developed. RESULTS: Within the Veterans Affairs texting system Annie, we programmed five 6-month text-messaging protocols that included cycles of 3 text message types: narrative messages, nonnarrative educational messages, and 2-way interactive messages assessing self-efficacy and behavior related to hypertension self-management. Each protocol corresponds to a single Veteran storyteller, allowing Veterans to choose the story that most resonates with their own life experiences. CONCLUSIONS: We crafted a culturally sensitive text-messaging protocol using narrative content referenced in Veteran stories to support effective hypertension self-management. Integrating narrative content into a mobile health texting intervention provides a low-cost way to support longitudinal behavior change. A randomized trial is underway to test its impact on the lifestyle changes and blood pressure of African American Veterans. TRIAL REGISTRATION: ClinicalTrials.gov NCT03970590; https://clinicaltrials.gov/ct2/show/NCT03970590. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/29423
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