Scaling from single-point sap velocity measurements to stand transpiration in a multi-species deciduous forest: uncertainty sources, stand structure effect, and future scenarios impacts

ABSTRACT A major challenge in studies estimating stand water use in mixed-species forests is how to effectively scale data from individual trees to the stand. This is the case for forest ecosystems in the northeastern USA where differences in water use among species and across different size classes have not been extensively studied, despite their relevance for a wide range of ecosystem services. Our objectives were to assess the importance of different sources of variability ontranspiration upscaling and explore the potential impacts of future shifts in species composition on forest water budget. We measured sap velocity in five tree species (Fagus grandiflora, Acer rubrum, A. saccharum, Betula alleghaniensis, B. papyrifera) in a mature and young stand in NH (USA). Our results showed that the greatest potential source of error was radial variability and that tree size was more important than species in determining sap velocity. Total sapwood area was demonstrated to exert a strong controlling influence on transpiration, varying depending on tree size and species. We conclude that the effect of potential species shifts on transpirationwill depend on the sap velocity, determined mainly by radial variation and tree size, but also on the sapwood area distribution in the stand

Scaling from single-point sap velocity measurements to stand transpiration in a multi-species deciduous forest: uncertainty sources, stand structure effect, and future scenarios impacts

ABSTRACT A major challenge in studies estimating stand water use in mixed-species forests is how to effectively scale data from individual trees to the stand. This is the case for forest ecosystems in the northeastern USA where differences in water use among species and across different size classes have not been extensively studied, despite their relevance for a wide range of ecosystem services. Our objectives were to assess the importance of different sources of variability ontranspiration upscaling and explore the potential impacts of future shifts in species composition on forest water budget. We measured sap velocity in five tree species (Fagus grandiflora, Acer rubrum, A. saccharum, Betula alleghaniensis, B. papyrifera) in a mature and young stand in NH (USA). Our results showed that the greatest potential source of error was radial variability and that tree size was more important than species in determining sap velocity. Total sapwood area was demonstrated to exert a strong controlling influence on transpiration, varying depending on tree size and species. We conclude that the effect of potential species shifts on transpirationwill depend on the sap velocity, determined mainly by radial variation and tree size, but also on the sapwood area distribution in the stand

Towards a Humean Solution of Vagueness in Language and Ontology

This paper explores how a Humean may respond to issues of vagueness in philosophy of language—and in extension—ontology. It begins with an examination of the sorites paradox and two common responses: epistemicism, and eliminativism. I then turn to David Hume’s conception of abstract ideas as a way to determine how vague terms refer and then compare this view to both epistemicism and eliminativism. The paper ends with a defense of the Humean view as a synthesis of the two, which ultimately questions the formulation of the sorites paradox as a proper use of language

Empowering Futures: Matthew\u27s Knights of Distinction Leadership E-Portfolio in Academic Excellence

My presentation centers on my E-Portfolio, seamlessly incorporating three key milestones from the Knights of Distinction program into significant events. Beginning with a brief personal introduction, I shared why I became a physics major, and explored the roots of my passion for space. Utilizing a visual aid, my poster board, I elucidated each focus area and its relevance to my aspirations and societal contributions. The first focus area was Citizenship and how I attended an “Industry BBQ” with the hopes of gaining valuable information to share it with other engineers. The second focus area was about leadership and my role as leader for a complex Java project. My third focus area was about my high-impact learning in my time in NASA’s L’SPACE academy where I gained many valuable skills and experiences through teamwork and the provided resources. To conclude, I reflected on the course\u27s impact while talking about creating reflective essays and a professional E-Portfolio, underscoring the pivotal role my E-Portfolio plays in shaping my future—an emblem of personal growth and professional significance.https://stars.library.ucf.edu/hip-2023fall/1033/thumbnail.jp

Ecological Niche Modeling of Pteronotropis Hubbsi, the Bluehead Shiner: Evaluating the Effects of Spatial Filtering and Maxent Features Across Various Spacial Extents

Ecological niche modeling (ENM) has been extensively applied as a reliable tool in conservation biology. Still, challenges abound in generating optimal models, especially when using limited occurrence data. The bluehead shiner, Pteronotropis hubbsi, a threatened species of concern, was modeled throughout its range within the U.S. South Central Plains Ecoregion. The portions of states that overlap this region include Texas, Oklahoma, Arkansas, and Louisiana. I used the Maxent software package (Phillips et al., 2006), as the ENM algorithm for this project. A maximum of 14 geospatial environmental layers (climatic, hydrologic, and geologic) were chosen to determine the species\u27 association with its environment. Numerous sources suggest Maxent\u27s default settings do not generate optimal model performance. Because of this, I compared models by first examining the effects of spatial filtering. Then, I tuned Maxent\u27s features (linear and hinge) and regularization multipliers across seven extents. All unfiltered datasets exhibited heavy overfitting and did not produce a model with an acceptable omission rate. For the tuning experiments using filtered datasets, all default settings experienced model overfitting, which constrains the algorithm\u27s predictive performance. Generally, models with regularization multipliers greater than three lose their discriminative ability where maps predict unrealistic habitat suitability within a majority of the study\u27s extent. The majority of optimal models with limited sample sizes required the following applications: spatial filtering of occurrence data, use of linear features, and a Regularization multiplier greater than the default. A jackknife test of variable importance determined that each extent relied on a unique combination of variables to predict habitat suitability, but Geology, Strahler Stream Order, River Basin, and Soils were the most consistent top four predictors throughout the various extents. This project demonstrates that tuning the Maxent algorithm, spatial filtering, and data reduction are required to generate optimal models. This information can be used in the effort to evaluate the conservation status of a rare, aquatic species by efficiently planning surveys to discover unknown populations

Biologics May Prevent Cardiovascular Events in Rheumatoid Arthritis by Inhibiting Coronary Plaque Formation and Stabilizing High-Risk Lesions.

ObjectiveTo evaluate whether biologic disease-modifying antirheumatic drugs (DMARDs) decrease cardiovascular disease (CVD) risk in rheumatoid arthritis (RA) and whether biologic DMARDs might have a beneficial effect on coronary plaque formation or progression.MethodsIn this single-center observational cohort study, 150 patients underwent computed tomographic angiography for evaluation of coronary atherosclerosis (total, noncalcified, mixed/calcified, and low-attenuation plaque); 101 had repeat assessments within a mean ± SD of 6.9 ± 0.3 years to evaluate plaque progression. All CVD events were prospectively recorded, including cardiac death, myocardial infarction, unstable angina, revascularization, stroke, claudication, and hospitalization for heart failure. The Framingham-D'Agostino score was used to assess cardiovascular risk. The segment stenosis score was used to measure plaque burden. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated.ResultsAfter adjustment for the segment stenosis score, the Framingham-D'Agostino score, and time-varying Disease Activity Score in 28 joints using the C-reactive protein level using marginal structural models, current biologic DMARD use was associated with lower long-term CVD risk (OR 0.15 [95% CI 0.04-0.60]). Noncalcified and low-attenuation plaque presence moderated the effect of biologic DMARDs on CVD risk; specifically, biologic DMARD use was associated with lower CVD risk in patients with noncalcified or low-attenuation plaque at baseline (OR 0.21 [95% CI 0.04-0.99] and OR 0.08 [95% CI 0.01-0.70], respectively), but not in those without noncalcified or low-attenuation plaque. Per-segment plaque progression analyses showed that biologic DMARD exposure was associated with transition of noncalcified to mixed/calcified plaque (OR 4.00 [95% CI 1.05-15.32]). Biologic DMARD exposure predicted a lower likelihood of new plaque forming in segments without plaque among patients without mixed/calcified plaque in other coronary segments (OR 0.40 [95% CI 0.17-0.93]), but not among those with calcification. Biologic DMARD treatment also predicted low-attenuation plaque loss (P = 0.042).ConclusionOur findings indicate that in RA, biologic DMARD use is associated with reduced CVD risk, protective calcification of noncalcified lesions, and lower likelihood of new plaque formation in patients with early atherosclerosis