Physical Sciences and Mathematics Commons^™

Patterns And Trends Of Organic Matter Processing And Transport: Insights From The Us Long-Term Ecological Research Network, Tamara K. Harms, Peter M. Groffman, Lihini Aluwihare, Christopher Craft, William R. Wieder, Sarah E. Hobbie, Sara G. Baer, John M. Blair, Serita D. Frey, Christina K. Remucal, Jennifer A. Rudgers, Scott L. Collins, John S. Kominoski, Becky A. Ball, Lter Om Working Group

Faculty Publications

Organic matter (OM) dynamics determine how much carbon is stored in ecosystems, a service that modulates climate. We synthesized research from across the US Long-Term Ecological Research (LTER) Network to assemble a conceptual model of OM dynamics that is consistent with inter-disciplinary perspectives and emphasizes vulnerability of OM pools to disturbance. Guided by this conceptual model, we identified unanticipated patterns and long-term trends in processing and transport of OM emerging from terrestrial, freshwater, wetland, and marine ecosystems. Cross-ecosystem synthesis combined with a survey of researchers revealed several themes: 1) strong effects of climate change on OM dynamics, 2) surprising patterns …

Does A Bottom-Up Mechanism Promote Hypoxia In The Mississippi Bight?, Virginie Sanial, Willard S. Moore, Alan M. Shiller

Faculty Publications

The Mississippi Bight, east of the Mississippi River, is a complex coastal ecosystem that, like the better-known Louisiana Shelf to the west, experiences seasonal bottom water hypoxia. However, input of allochthonous nutrients from the Mississippi River to the Mississippi Bight appears to be limited, begging the question of what drives seasonal hypoxia in this system. Prior research has suggested submarine groundwater discharge (SGD) could be an overlooked component of the Mississippi Bight biogeochemical system. We thus examined the hypothesis that SGD provides a “bottom up” driver for seasonal hypoxia in this area. We used a multi-tracer approach based on known …

Following The Lithium: Tracing Li-Bearing Molecules Across Age, Mass, And Gravity In Brown Dwarfs, Ehsan Gharib-Nezhad, Mark S. Marley, Natasha E. Batalha, Channon Visscher, Richard S. Freedman, Roxana E. Lupu

Faculty Work Comprehensive List

Lithium is an important element for the understanding of ultracool dwarfs because it is lost to fusion at masses above ∼68 MJ. Hence, the presence of atomic Li has served as an indicator of the nearby H-burning boundary at about 75 MJ between brown dwarfs and very low mass stars. Historically, the “lithium test,” a search for the presence of the Li line at 670.8 nm, has been a marker if an object has a substellar mass. While the Li test could, in principle, be used to distinguish masses of later-type L–T dwarfs, Li is predominantly no longer found as …

Perron Theorem For Delay Differential Equations, William Barker

Theses and Dissertations

This note discusses results furthering the study of bounded solutions of non-homogeneous second-order differential equations with delay. The equation of interest has already been shown to possess unique bounded solutions in accordance to Perron's Theorem. We will determine the negativity of the solutions given a positive forcing term by establishing a uniform bound regarding small time delay.

Heat Exposure Effect On Ghanaian Mining Workers: A Mediated-Moderation Approach, Victor Fannam Nunfam, Ebenezer Afrifa-Yamoah

Research outputs 2014 to 2021

The lack of empirical evidence on the effect of heat exposure on the health and safety, productivity, psychological behaviour and social well-being outcomes of small- and large-scale mining workers in Africa has derailed concrete policy directions and interventions. An explanatory cross-sectional survey involving 320 small- and large-scale mining workers was used to assess this research gap. A path analysis was used to model health and safety, productivity, psychological behaviour and social well-being as a function of heat exposure, mediated and moderated by adaptation strategies and barriers, while controlling for age, gender, level of education, years of working experience and workplace …

Generalized Grassmann Algebras And Applications To Stochastic Processes, Daniel Alpay, Paula Cerejeiras, Uwe Kaehler

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper, we present the groundwork for an Itô/Malliavin stochastic calculus and Hida's white noise analysis in the context of a supersymmetry with Z₃-graded algebras. To this end, we establish a ternary Fock space and the corresponding strong algebra of stochastic distributions and present its application in the study of stochastic processes in this context.

Energy Revolution Under Vision Of Carbon Neutrality, Zhen Huang, Xiaomin Xie

Bulletin of Chinese Academy of Sciences (Chinese Version)

Climate change has emerged as one of the major challenges faced by mankind. It has become a non-traditional global security issue, which causes a serious threat to the survival of human being and sustainable development. China's commitment to peak carbon emissions by 2030 and achieve carbon neutrality by 2060 has important strategic significance for building a modern socialist country with harmonious coexistence between human and nature. Facing the challenge of China's carbon peak and carbon neutrality, this study proposes, through energy revolution, to promote electric decarbonization and zero carbonization power and zero carbonization fuel on the energy supply side, and …

Path Of Digital Technology Promoting Realization Of Carbon Neutrality Goal In China’S Energy Industry, Xiaohong Chen, Dongbin Hu, Wenzhi Cao, Wei Liang, Xuesong Xu, Xiangbo Tang, Yangjie Wang

Bulletin of Chinese Academy of Sciences (Chinese Version)

In the era of digital economy, digital technology is the best tool to achieve China's goal of carbon neutrality. The energy industry is the largest source of carbon emissions in China, and how to use digital technology to peak the carbon dioxide emissions and achieve carbon neutrality goal in energy industry has attracted widespread attention. The article first explains the important strategic role of digital technology in carbon neutrality, and then analyzes the related theoretical research and application progress of digital technology and carbon emission reduction in the literature, revealing the problems of current digital technology applied to carbon neutrality …

Toward Carbon Neutrality: Circular Economy Approach And Policy Implications, Wendong Wei, Zhujun Chen, Yong Geng, Wenqiu Cai, Hanbin Liu

Bulletin of Chinese Academy of Sciences (Chinese Version)

It is challenging to promote global climate change governance under the current complicated international contexts. As a country with the largest carbon emission, China has committed to achieve carbon peak by 2030 and carbon neutrality by 2060. However, carbon neutrality is a complex system engineering and relies on the implementation of circular economy. Based upon “3R” principles of reduce, reuse, and recycle, this study investigates the internal relations between circular economy and carbon neutrality and identifies the key position of circular economy in achieving carbon neutrality targets. Several policy implications are raised to help promote the development of circular economy …

Analysis On Transformation And Characteristics Of American Hydrogen Energy Strategy Under Carbon Neutralization Goal, Feng Wei, Xiaobo Ren, Lin Gao, Guoqing Gao, Chaofeng Zhou

Bulletin of Chinese Academy of Sciences (Chinese Version)

As an important means to achieve the goal of carbon neutralization, hydrogen energy has attracted global attention. As the United States has more than 30 years of practical experience in hydrogen energy R&D and application, this study conducts a detailed investigation on the hydrogen energy development plan and strategy formulated by the U.S. government, analyzes the U.S. hydrogen energy strategy and development objectives, direction and achievements since 1990, and focuses on the latest U.S. hydrogen energy development strategy in 2020 and the hydrogen energy breakthrough plan in 2021. It is concluded that the current US government has moved from initially …

Building Substrate For National Strategy Of New Infrastructure Construction—Practice And Thought Of Information Superbahn Testbed, Xiaohong Wang, Sa Wang, Hongwei Tang, Xiaohui Peng

Bulletin of Chinese Academy of Sciences (Chinese Version)

This study first introduces the background and status quo of the national strategy of New Infrastructure Construction. Next, the study systematically reviews the development and impact of information infrastructure testbed in USA, as well as the new challenge for information infrastructure in the intelligent era of the ternary integration of man-machine-things. Then, we propose the Information Superbahn technology innovation program and the OneComputer project, which is a large-scale testbed for the next generation information infrastructure. Furthermore, we present the latest progress and some thoughts about methodology of this large project. Finally, this study looks into the project's future development under …

Research On China’S Energy Development Strategy Under Carbon Neutrality, Jian Su, Yingbo Liang, Lin Ding, Guosheng Zhang, He Liu

Bulletin of Chinese Academy of Sciences (Chinese Version)

China has pledged to reach peak carbon dioxide emission by 2030, and carbon neutrality by 2060 at the Seventy-Fifth Session of the United Nations General Assembly in 2020. As the largest energy consumer and emitter of greenhouse gases, carbon peak and carbon neutrality targets have posed a high requirement for China's sustainable development of energy and economy. In recent years, even though the growth rate of China's energy consumption has decreased, and carbon dioxide emissions gradually enter the plateau, fossil fuels still supply more than 80% of the energy consumption in China. Besides learning from the adjustment of energy consumption …

Evaluating Economic And Social Benefits Of Accelerated Energy Transition, Hongyu Zhang, Xiaodan Huang, Da Zhang, Xiliang Zhang

Bulletin of Chinese Academy of Sciences (Chinese Version)

To achieve carbon neutrality, China's energy system needs a radical transition, and the development of new energy is of central importance. Based on the integrated assessment modeling framework, this study compares economic and social costs and benefits between a scenario reflecting the current energy transition momentum and a scenario of accelerated energy transition. We show that the accelerated energy transition dominated by new energy is essential to achieve carbon neutrality before 2060 and the air quality target required by Beautiful China. The large development of wind and solar power will further reduce their technology costs and the overall energy costs, …

Selenium Probes For The Detection Of Thioredoxin Reductase Activity, Tendai Joseph Mafireyi

Dissertations and Theses

The identification and quantification of proteins and enzymatic activity in living tissues frequently requires the use of invasive procedures such as biopsy. These techniques can inhibit measurements of protein levels in real-time, and the disruption of tissue can lead to the loss of important information concerning the spatial distribution and differential activities in various cell types. The use of small organic fluorescent probes that rely on activation or accumulation within a tissue embody robust methods of detection that address these issues. This dissertation describes the design, synthesis and evaluation of fluorescent probes that can detect the enzyme thioredoxin reductase (TrxR). …

Adapting Tropical Forages To Low-Fertility Soils, Idupulapati M. Rao

IGC Proceedings (1977-2023)

Tropical forages growing in low-fertility acid soils usually increase the amount of dry matter partitioned to roots at the expense of shoot growth, but substantially different adaptive attributes to such soils have been found, both between and within species. By possessing the C₄ pathway of photosynthesis, grasses are more efficient than legumes in using N, Ca, and P, whereas legume roots are more efficient in extracting nutrients from low-fertility soils. Phosphorus uptake efficiency (mg of P uptake in shoot biomass per unit root length) of the legume Arachis pintoi is several times higher than that of the grass Brachiaria …

Adaptation Of Forage Species To Drought, D. J. Barker, J. R. Caradus

IGC Proceedings (1977-2023)

Variability in rainfall is the single greatest cause of variation in forage production for a given site. Current climate scenarios predict future annual rainfall to decrease at some geographic regions. The intensity of future rainfall is also predicted to increase at other regions, with the expectation of greater variability in soil moisture. The adaptation of forage species to drought is an issue that is likely to remain with us into the future.

Precise definitions are critical to water relations work, and imprecise use of terms has complicated comparisons of some studies on plant response to drought. Drought is a purely …

Spittlebugs: Bioecology, Host Plant Resistance And Advances In Ipm, José R. Valério, C. Cardona, D. C. Peck, G. Sotelo

IGC Proceedings (1977-2023)

Several species and genera of spittlebugs (Homoptera: Cercopidae) are economic pests of grasses in tropical America. These insects compete with grazing animals by reducing forage availability and quality. They may cause serious losses on millions of hectares of improved pastures based on cultivars of several species of Brachiaria (signal grasses). Except for the cultivar Marandu, most of the available commercial cultivars of Brachiaria are susceptible to spittlebugs. In spite of their economic importance, much research need to be done yet. Such insect-plant system encompasses a diverse group of spittlebug species, a diverse group of forage grass species, which are under …

Grassland Plant Diseases: Management And Control, S. Chakraborty

IGC Proceedings (1977-2023)

Grasslands cover 40% of the earth’s surface and support animal-based industries; maintain soil cover, watersheds and biodiversity; sequester atmospheric carbon for storage in the soil; and provide tourism and leisure income. Diseases continue to decrease herbage and seed yield and reduce nutritive value and palatability of grasslands to impact on animal health and productivity but realistic data on loss are hard to find. Although principles of disease management remain the same, strategies used in crop protection can not be directly applied to grasslands due to differences in heterogeneity, population size, density and spatial distribution and population continuity. Low per hectare …

Soil Carbon And Nitrogen Dynamics After Pasture Installation In The Amazon Region, C. C. Cerri, M. Bernoux, C. E. P. Cerri

IGC Proceedings (1977-2023)

The objective of this paper is to present the soil carbon (C) and nitrogen (N) dynamics in a chronosequence made of a forest and pastures of different ages established in a Oxisol in the Western Brazilian Amazon Basin. The results of soil Carbon and Nitrogen stocks and gases fluxes were discussed. Stable ¹³C isotopic technique was used to calculate for a determinate age of pasture installation, the proportion of soil C remaining from the forest system and the proportion of soil C introduced by the grasses of the pasture system. The C lost from the original pool under the …

Micronutrients In Grassland Production, U. C. Gupta, F. A. Monteiro, J. C. Werner

IGC Proceedings (1977-2023)

Micronutrients, also known as trace minerals, which chiefly include boron (B), molybdenum (Mo), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe), are required in extremely small quantities by crops and livestock. Their name, however, is not meant to imply their role is minor. Their lack, e.g., can cause serious crop production problems in forages and health disorders in livestock. This presentation includes the response of forage legumes and grasses to micronutrients, their deficiency and sufficiency levels in forages and their sufficiency levels in livestock. Forage legumes are more responsive to micronutrients, particularly B and Mo, than grasses. There are …

Pasture Seed Production Technology In Brazil, Ronaldo Pereira De Andrade

IGC Proceedings (1977-2023)

Efficient and low cost production systems, which rely on the use of cultivated pastures, are the basis of beef and milk production in Brazil. The success of these pasture-based systems would not be possible without the support of an aggressive and dynamic pasture seed production sector to supply the internal demand, which is estimated to be around 90000 tons per year. The market is dominated by grass species and among them, Brachiaria. brizantha cv. Marandu accounts for more than 80% of the total seed volume in the market. Seed production systems in Brazil vary from highly specialized to opportunistic accordingly …

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Shallow Rupture Propagation Of Pleistocene Earthquakes Along The Hurricane Fault, Ut, Revealed By Hematite (U-Th)/He Thermochronometry And Textures, Madison P. Taylor, Alexis K. Ault, Margaret L. Odlum, Dennis L. Newell

Geoscience Faculty Research

The material properties and distribution of faults above the seismogenic zone promote or inhibit earthquake rupture propagation. We document the depths and mechanics of fault slip along the seismically active Hurricane fault, UT, with scanning and transmission electron microscopy and hematite (U-Th)/He thermochronometry. Hematite occurs as mm-scale, striated patches on a >10 m2 thin, mirror-like silica fault surface. Hematite textures include bulbous aggregates and cataclasite, overlain by crystalline Fe-oxide nanorods and an amorphous silica layer at the slip interface. Textures reflect mechanical, fluid, and heat-assisted amorphization of hematite and silica-rich host rock that weaken the fault and promote rupture propagation. …

Meeting The Changing Need For Herbage Seed Quality Assurance In The 21st Century, D. S. Loch, K. G. Boyce

IGC Proceedings (1977-2023)

Quality assurance is a key element in the herbage seed supply chain. The measurement and management of seed quality is discussed in terms of its four main parameters - genetic, physical, vital, and phytosanitary quality - which provide information on the expected performance of herbage seed when sown in the field. During the past century, seed quality management systems have evolved in response to national and regional differences in economic development, crop characteristics, merit testing, and the demands of international trade. The pace of change in the management of seed quality assurance has intensified in developed countries over the past …

Novel Grasses And Legumes Germplam: Advances And Perspectives For Tropical Zones, E. A. Pizarro

IGC Proceedings (1977-2023)

It has been the aim, in the present article, to bring together as much as possible scientific evidence and experience in new available germplasm for tropical zones.

The economic importance of the Brachiaria, Paspalum and Pennisetum grasses is well established. New germplasm has become available since 1980. This paper reviews evaluations of Brachiaria accessions in humid lowlands and savannas of tropical America. The selection criteria need to be revised. Also, it is necessary to expose the new material as early as possible to farmers in order to select new germplasm with high chances of adoption.

Within the genus Paspalum …

Temperate Forage Grass-Legume Mixtures: Advances And Perspectives, A. S. Laidlaw, N. Teuber

IGC Proceedings (1977-2023)

The paper summarises some of the advances which have been made a) in increasing understanding of the grass-legume association, especially grass-white clover, so that the association can be more predictably exploited and b) in overcoming limitations in the use of such mixtures. The contribution which forage legumes make to the N economy of mixtures is reviewed with estimates approaching 400 kg N ha^-1 for some. Uptake by grass of legume- derived N (N transfer) reduces soil mineral N levels and increases the proportion of fixed N in the total legume N relative to legume monoculture. Although N transfer also …

An Accelerated Variance-Reduced Conditional Gradient Sliding Algorithm For First-Order And Zeroth-Order Optimization, Xiyuan Wei, Bin Gu, Heng Huang

Machine Learning Faculty Publications

The conditional gradient algorithm (also known as the Frank-Wolfe algorithm) has recently regained popularity in the machine learning community due to its projection-free property to solve constrained problems. Although many variants of the conditional gradient algorithm have been proposed to improve performance, they depend on first-order information (gradient) to optimize. Naturally, these algorithms are unable to function properly in the field of increasingly popular zeroth-order optimization, where only zeroth-order information (function value) is available. To fill in this gap, we propose a novel Accelerated variance-Reduced Conditional gradient Sliding (ARCS) algorithm for finite-sum problems, which can use either first-order or zeroth-order …

Ensemble Learning Using Error Correcting Output Codes: New Classification Error Bounds, Hieu Nguyen, Mohammed Sarosh Khan, Nicholas Kaegi, Shen-Shyang Ho, Jonathan Moore, Logan Borys, Lucas Lavalva

College of Science & Mathematics Departmental Research

New bounds on classification error rates for the error-correcting output code (ECOC) approach in machine learning are presented. These bounds have exponential decay complexity with respect to codeword length and theoretically validate the effectiveness of the ECOC approach. Bounds are derived for two different models: the first under the assumption that all base classifiers are independent and the second under the assumption that all base classifiers are mutually correlated up to first-order. Moreover, we perform ECOC classification on six datasets and compare their error rates with our bounds to experimentally validate our work and show the effect of correlation on …

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Novel Theorems And Algorithms Relating To The Collatz Conjecture, Michael R. Schwob, Peter Shiue, Rama Venkat

Mathematical Sciences Faculty Research

Proposed in 1937, the Collatz conjecture has remained in the spotlight for mathematicians and computer scientists alike due to its simple proposal, yet intractable proof. In this paper, we propose several novel theorems, corollaries, and algorithms that explore relationships and properties between the natural numbers, their peak values, and the conjecture. These contributions primarily analyze the number of Collatz iterations it takes for a given integer to reach 1 or a number less than itself, or the relationship between a starting number and its peak value.