David M. Merritt results 19
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The Toxicology Investigators Consortium 2024 Annual ReportNARA Subscribed
Your brain doesn’t look a day past 70! Cross-sectional associations with brain-predicted age in the cognitively-intact oldest-oldNARA Subscribed
The cognitively-intact oldest-old (85 +) may be the most-resilient members of their birth cohort; due to survivorship effects (e.g., depletion of susceptibles), risk factors associated with brain aging biomarkers in younger samples may not generalize to the cognitively-intact oldest-old. We evaluated associations between established aging-related risk factors and brain-predicted age difference (brainPAD) in a cross-sectional c...
A Review of Abrupt Permafrost Thaw: Definitions, Usage, and a Proposed Conceptual FrameworkNARA Subscribed
Purpose of Review We review how ‘abrupt thaw’ has been used in published studies, compare these definitions to abrupt processes in other Earth science disciplines, and provide a definitive framework for how abrupt thaw should be used in the context of permafrost science. Recent Findings We address several aspects of permafrost systems necessary for abrupt thaw to occur and propose a framework for classifying permafrost process...
Variable seed bed microsite conditions and light influence germination in Australian winter annualsNARA Subscribed
Environmentally cued germination may play an important role in promoting coexistence in Mediterranean annual plant systems if it causes niche differentiation across heterogeneous microsite conditions. In this study, we tested how microsite conditions experienced by seeds in the field and light conditions in the laboratory influenced germination in 12 common annual plant species occurring in the understorey of the York gum-jam...
Ecosystems are defined, studied, and managed according to boundaries constructed to conceptualize patterns of interest at a certain scale and scope. The distinction between ecosystems becomes obscured when resources from multiple origins cross porous boundaries and are assimilated into food webs through repeated trophic transfers. Ecosystem compartments can define bounded localities in a heterogeneous landscape that simultaneo...
Permafrost thaw can alter the soil environment through changes in soil moisture, frequently resulting in soil saturation, a shift to anaerobic decomposition, and changes in the plant community. These changes, along with thawing of previously frozen organic material, can alter the form and magnitude of greenhouse gas production from permafrost ecosystems. We synthesized existing methane (CH 4 ) and carbon dioxide (CO 2 ) produc...
Environmental and physical controls on northern terrestrial methane emissions across permafrost zonesNARA Subscribed
Methane ( CH 4 ) emissions from the northern high‐latitude region represent potentially significant biogeochemical feedbacks to the climate system. We compiled a database of growing‐season CH 4 emissions from terrestrial ecosystems located across permafrost zones, including 303 sites described in 65 studies. Data on environmental and physical variables, including permafrost conditions, were used to assess controls on CH 4 emis...
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