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Fine root respiration in Quercus rubra (L.) aligns with the economics trade-offs in bi-dimensional root trait space
No full textPlant economic theory argues that growth strategies maximize either the rate or longevity of return per resource investment in a unidimensional trade-off. Belowground trade-offs may not mimic those aboveground due to soil resource heterogeneity, different physical constraints imposed by the shape of roots compared to leaves, and fungal symbioses, and often multiple dimensions of variation are found. Root respiration represents a substantial carbon flux out of forest ecosystems, but its placement in these trade-offs is unclear, and its incorporation into carbon cycle models is limited by available data. Most research on root traits has focused on interspecific variability, but here, we investigated whether trade-offs among one species\u27 populations align with those between species by sampling Quercus rubra populations along a Midwest, USA latitudinal gradient. Across populations, we assessed whether fine root traits follow uni- or multidimensional trade-offs, and how these axes relate to root respiration. Respiration rates, morphological traits, and root nitrogen were measured on excised fine roots at 14 sites, spanning a wide variety of environmental conditions, and then analyzed for trade-off axes. We uncovered substantial root trait variation among Q. rubra populations that aligned with two distinct trade-offs, one between branching intensity and average diameter, and a second with root tissue density on one end and specific root length, root nitrogen concentration, and root specific respiration on the other. Reliance on ectomycorrhizal fungi, which colonize root tips, may be a possible explanation for the first axis, with higher branching intensity representing more collaboration. Along the latter axis, root specific respiration increased with root nitrogen concentration and decreased with root tissue density. These results support a similar bi-dimensional trait space between Q. rubra populations to that between species, with an economics trade-off that might be a useful predictor of the fine root respiration carbon flux
Insights on avian life history and physiological traits in Central Africa: ant-following species have young-dominated age ratios in secondary forest
Get PDFThe Congo Basin rainforest and adjacent Lower Guinea Forest constitute the second largest tract of lowland tropical rainforest in the world. As with the rest of the continent, human population is increasing rapidly and forest degradation is ubiquitous. Forest degradation through logging has pervasive negative effects on ecosystems, but selective logging is considered less impactful than clearcutting. Recent research in Afrotropical forest shows that certain avian species and guilds are more affected by selective logging than others (e.g., specialist insectivores such as followers of Dorylus driver ants); however, the mechanisms behind these patterns are poorly known. In an eight-year mist-netting effort in Equatorial Guinea, we caught 1193 birds in primary forest and high-grade selectively logged forest to determine the effect of disturbance on six demographic and physiological measures on birds. We compared five life history and population traits for ten insectivorous species: proportion of breeding and molting birds, molt-breeding overlap, bird age, and a body mass index. We also analyzed the concentrations of the stress hormone feather corticosterone (fCORT) in five species. All three strict ant-following species (Alethe castanea, Chamaetylas poliocephala, Neocossyphus poensis), and the Muscicapid robin Sheppardia cyornithopsis had a higher proportion of first year birds in secondary forest. Furthermore, two ant-followers, A. castanea and C. poliocephala, had a higher proportion of individuals molting in primary forest. Finally, only Illadopsis cleaveri had higher body condition in secondary forest. We found no differences in breeding status, molt-breeding overlap or fCORT between forest types. Using a long-term mist-netting effort, we use measures taken from birds in-the-hand to go beyond insights from point counts alone; we gain valuable insights into the demography and physiology of Afrotropical birds occupying variably degraded lowland tropical rainforest
Quantifying the impact of workshops promoting microbiome data standards and data stewardship
Get PDFThe field of microbiome research continues to grow at a rapid pace, with multi-omics approaches becoming widely used to interrogate diverse microbiome samples. However, due to lagging awareness and implementation of standards and data stewardship, many datasets are produced that are not comparable, reproducible, or reusable. In 2021, the National Microbiome Data Collaborative launched its Ambassador Program, which utilizes a community-learning model to annually train a cohort of early-career researchers in microbiome data stewardship best practices. These Ambassadors then host workshops and other events to communicate these themes to their respective microbiome research communities. To quantify the impact of this learning model for promoting awareness of and experience with microbiome data, we conducted a survey of workshop participants from events hosted by the 2023 Ambassador cohort. The 2023 cohort of 13 National Microbiome Data Collaborative Ambassadors collectively hosted 21 events, reaching over 550 researchers. The Ambassadors distributed an anonymous post-workshop survey to their event participants to quantify the effectiveness of the training materials, the workshop format, and the thematic content. From the 21 events, survey results were successfully collected for 15 of those events from a total of 122 researchers. Overall, 122 participants working with a range of microbiome types and from a variety of institutions responded to the survey and reported overwhelmingly positive experiences with the workshop content and materials, with 98% of respondents reporting that they gained knowledge from the event. Participants across the events also reported an increase in their post-workshop understanding of metadata standards, principles for microbiome data management and reporting, and the importance of standardization in microbiome data processing. Participants also expressed a willingness to apply what they learned about microbiome data stewardship to their own research. The results of this study demonstrate the effectiveness of hands-on workshops and community-learning for communicating data stewardship best practices to microbiome researchers. The lessons learned and details about the implementation of this cohort-based learning model contained herein are intended to assist other groups in their efforts to create or improve similar learning strategies
The associations of negative and disorganization symptoms with verbal fluency in schizophrenia: the mediation effect of processing speed and cognitive flexibility
Get PDFBackground: Psychopathological symptoms appear important for cognitive functions in schizophrenia. Nevertheless, the factors and their impact on relationships between negative or disorganization symptoms and verbal fluency are still debatable. The preliminary objective of the study was to compare verbal fluency, including clustering and switching as cognitive strategies, executive functions, and processing speed between individuals with schizophrenia (SZ) and healthy controls (HC). The main aim of the study was to investigate mediation models and identify whether relationships between negative and disorganization symptoms and verbal fluency in schizophrenia are mediated by cognitive flexibility and processing speed. Methods: Semantic (animal and fruit) and phonemic (letter k and letter f) fluency tasks, the Berg Card Sorting Test (BCST), and the Color Trails Test (CTT) were administered in the SZ group (n = 108) and a matched HC group (n = 108). The Positive and Negative Syndrome Scale (PANSS) was applied to measure psychopathological symptoms in schizophrenia patients. Results: SZ produced fewer words, had larger cluster size, and fewer switches in semantic fluency than HC. Moreover, the SZ group had longer completion time in CTT 1 and CTT 2 and higher percent of perseverative and non-perseverative errors in BCST than HC. Three mediation models demonstrated good fit indices, suggesting that processing speed and cognitive flexibility were significant mediators for relationships between: (1) psychopathological symptoms and productivity or semantic clustering in animal fluency; (2) negative symptoms and productivity in semantic or phonemic fluency; and (3) disorganization symptoms and productivity in semantic fluency. Conclusions: Individuals with schizophrenia are characterized by a specific performance profile on verbal fluency tasks. They manifest poor productivity and problems using cognitive strategies for semantic fluency. Referring to executive functioning, schizophrenia patients exhibit decreased cognitive flexibility, problem-solving, and formulating concepts, as well as slow processing speed. It was found that processing speed and cognitive flexibility may be understood as the neuropsychological mechanisms modifying the relationships between negative symptoms, disorganization symptoms, and semantic and phonemic fluency. Therefore, these results provide a foundation for including cognitive flexibility and processing speed in cognitive remediation for schizophrenia patients
A reinterpreted discrete fracture model for wormhole propagation in fractured porous media
No full textWormholes are high-permeability, deep-penetrating, narrow channels formed during the acidizing process, which serves as a popular stimulation treatment. For the study of wormhole formation in naturally fractured porous media, we develop a novel hybrid-dimensional two-scale continuum wormhole model, with fractures represented as Dirac-δ functions. As an extension of the reinterpreted discrete fracture model (RDFM) [50], the model is applicable to nonconforming meshes and adaptive to intersecting fractures in reservoirs without introducing additional computational complexity. A numerical scheme based on the local discontinuous Galerkin (LDG) method is constructed for the corresponding dimensionless model to accommodate the presence of Dirac-δ functions and the property of flux discontinuity. Moreover, a bound-preserving technique is introduced to theoretically ensure the boundedness of acid concentration and porosity between 0 and 1, as well as the monotone increase in porosity during simulation. The performance of the model and algorithms is validated, and the effects of various parameters on wormhole propagation are analyzed through several numerical experiments, contributing to the acidizing design in fractured reservoirs
Development of a Sustainable Slow-release De-icing Additive for Asphalt Pavements Using Lignin Fiber
No full textIn cold weather, ice on asphalt pavements can lead to slippery surfaces, increasing the risk of vehicle accidents and posing threats to human safety. This study selects lignin fiber (LF) as a carrier to prepare a new de-icing additive. A slow-release de-icing emulsified asphalt fog seal (SDFS) was formulated with this additive and emulsified asphalt. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed that LF effectively adsorbed HCOONa, with the sodium content on the fiber surface increasing from 0.91% to 5.64% after adsorption. The experiments demonstrated that SDFS can delay the freezing time of water by approximately 50% and lower the freezing point of water on the road surface. De-icing experiments showed that after 8 impacts, the de-icing rate of the Marshall specimen coated with SDFS reached 91.52%, whereas the common Marshall specimen had a de-icing rate of only 38.35% after the same number of impacts. The abrasion experiments showed that SDFS meets the requirements for road surface applications and retains its de-icing capability even after abrasion. Furthermore, molecular dynamics simulations were employed in this study to demonstrate that salt ions delay freezing by inhibiting the formation and growth of ice nuclei in the solution. In conclusion, SDFS can effectively prevent icing on asphalt pavements and offers good performance for road use
From Theory to Practice: Validating a High-Voltage Direct Current (HVDC) Experimental Setup for Traveling Wave Analysis
No full textThis paper presents an experimental investigation of traveling wave phenomena in high voltage direct current (HVDC) systems, aiming to advance the understanding and application of traveling wave-based fault detection and protection technologies. A low-scale HVDC experimental setup was developed, incorporating a 3 km DC cable connected to diode-based rectifiers and IGBT-based inverters, along with associated control and measurement systems. The setup enables the controlled application of faults, allowing for the detailed observation of traveling wave propagation under various fault conditions. Experimental results validate the effectiveness of the setup in replicating real-world conditions and demonstrate the potential of traveling wave analysis for improving fault location accuracy and the speed of response in HVDC systems. The findings will contribute to the development of more reliable and efficient protective devices for HVDC networks, ensuring stable power transmission
Trends in tree improvement methods: from classical breeding to genomic technologies
No full textGenetic improvement of trees is a key avenue for enhancing the productivity and quality of forest products. There is a need to improve the trees’ ability to adapt to changes in the environment including increases in frequency and intensity of biotic and abiotic stress, as well as to produce more forest products such as pulp, timber and other bioproducts. For efficient tree improvement, selecting a suitable breeding or improvement method is essential. Here, we reviewed the existing literature and conducted a meta-analysis using more than 1,500 scholarly articles published between 1990–2021. We categorized the articles into three broad tree improvement categories, 1) conventional or classical breeding, 2) marker-assisted- or genomic-selection, and 3) genetic modification or editing. The results of our meta-analysis indicated that higher adaptability, productivity, and quality are the main objectives of tree improvement approaches throughout time. Growth, quality, and biotic and abiotic stress tolerance-related traits are considered the most important. In the 1990s to early 2000s, conventional breeding methods were the most used category, but with the advent and development of state-of-the-art genetics, genomics, bioinformatics, and artificial intelligence tools, we can improve trees more efficiently and affordably. Genomic selection and genetic modification of non-model tree species are becoming more popular. Our analysis provides future directions and trends for selecting more efficient tree improvement techniques in a system dependent manner
SUGAR MAPLE (ACER SACCHARUM MARSH.) TREE-RING GROWTH AND CARBON STABLE ISOTOPE RESPONSES TO NITROGEN AND CLIMATE
Get PDFThis dendrochronological and stable carbon isotope study used tree rings from sugar maple (Acer Saccharum Marsh.) collected at long-term nitrogen (N) amended sites throughout Michigan to understand N amendment and deposition, climate, and growth relationships. Climate responses varied by site, however, we found importance in grouping sites by “productivity” which is related to inherent N and soil nutrients. Our results did not detect an overall effect of N amendments on growth during the treatment period. However, data shows N amendments benefiting larger diameter trees, while smaller diameter trees responded more positively without amendments, especially on more productive sites. Results from the stable carbon isotope analysis imply that leaf gas exchange at less productive sites is more influenced by moisture whereas more productive sites are more influenced by light conditions. Our findings suggest that soil characteristics and tree size are important factors to site specific responses to climate for sugar maple
NEAR-INFRARED HEMICYANINE AND BODIPY SENSORS FOR MONITORING MITOCHONDRIAL VISCOSITY IN LIVE CANCER CELLS, DROSOPHILA MELANOGASTER LARVAE, AND ADPKD KIDNEY TISSUE
No full textTwo near-infrared fluorescent sensors, sensor A and sensor B, were synthesized and characterized. Sensor A was a hemicyanine derived structure, and sensor B was a BODIPY derived sensor. The sensors were tested to measure their ability to monitor viscosity, and sensor A was used to monitor viscosity in live cells. Both sensors were found to be effective in monitoring the viscosity level through optical measurements with glycerol. Sensor A was found to be successful in monitoring mitochondrial viscosity in HeLa MBA-MD-453 and MDA-MB-231 cell lines. It was also successful in monitoring viscosity in Drosophila melanogaster larvae as well as in ADPKD affected mice kidney tissue. In all of these scenarios, the fluorescent intensity increased with viscosity. Sensor A has provided significant evidence that it would be a useful tool in monitoring mitochondrial viscosity in a variety of cellular conditions