Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 34531 - 34560 of 302419

Full-Text Articles in Physical Sciences and Mathematics

Feasibility Study Of The Metaverse Technology In Coal Mine Emergency Training And Drills, Guo Yangyang Jan 2022

Feasibility Study Of The Metaverse Technology In Coal Mine Emergency Training And Drills, Guo Yangyang

Coal Geology & Exploration

Coal mine safety training and emergency drills are effective measures to prevent disasters and accidents. At this stage, however, there are problems such as the boring training content, drills emphasizing “performance” rather than “practice”, and formalism. Metaverse technology integrates VR, AR, 3D, blockchain, Internet of things, AI, digital twin and other technologies, therefore, it is characterized by intuitiveness, strong interaction and high knowledge conversion rate in coal mine safety training and emergency drills, which can well solve the above problems. Now the metaverse technology is increasingly mature from hardware, software to various supporting facilities, while it is still faced with …

Go to article

Resistivity Detection And Its Application In Underground Coal Mine Directional Boreholes, Li Bofan, Liu Lei, Fan Tao, Jiang Qiping, Wang Jie Jan 2022

Resistivity Detection And Its Application In Underground Coal Mine Directional Boreholes, Li Bofan, Liu Lei, Fan Tao, Jiang Qiping, Wang Jie

Coal Geology & Exploration

The working face threatened by high gas or Ordovician limestone water pressure generally adopts directional drilling technology to carry out fracturing or grouting works at the bottom of the working face before mining to ensure the safety of mining. In-hole probing in directional boreholes in the bottom plate can reveal the hidden structures in the working face in a more detailed way, and can also realize “one hole for multiple uses”. In order to solve the detection problem in the directional drilling, a method of DC resistivity detection in the horizontal directional drilling is proposed. To solve the problem of …

Go to article

Robust Error Estimation Based On Factor-Graph Models For Non-Line-Of-Sight Localization, O. Arda Vanli, Clark N. Taylor Jan 2022

Robust Error Estimation Based On Factor-Graph Models For Non-Line-Of-Sight Localization, O. Arda Vanli, Clark N. Taylor

Faculty Publications

This paper presents a method to estimate the covariances of the inputs in a factor-graph formulation for localization under non-line-of-sight conditions. A general solution based on covariance estimation and M-estimators in linear regression problems, is presented that is shown to give unbiased estimators of multiple variances and are robust against outliers. An iteratively re-weighted least squares algorithm is proposed to jointly compute the proposed variance estimators and the state estimates for the nonlinear factor graph optimization. The efficacy of the method is illustrated in a simulation study using a robot localization problem under various process and measurement models and measurement …

Go to article

Forage Yield Of Oat On The Four Altitude Regions Of The Qinghai-Tibetan Plateau, H. B. Zhang, C. T. Liu, J. Q. Deng, X. L. Yang Jan 2022

Forage Yield Of Oat On The Four Altitude Regions Of The Qinghai-Tibetan Plateau, H. B. Zhang, C. T. Liu, J. Q. Deng, X. L. Yang

IGC Proceedings (1993-2023)

Forage oat (Avena sativa L.) for livestock in Qinghai-Tibet Plateau may be used biomass under widely different altitude conditions. To assess the effect of altitude on the biomass of oats, we conducted an experiment to explore the adaptability of forage oat Jiayan No. 2 in different altitudes for better agronomic traits and higher forage yield. Four regions included Hezheng county (2207 m a.s.l) and Tianzhu county (2407 m a.s.l), Gansu province, Haiyan county (3042 m a.s.l), Qinghai province and Hongyuan county (3460 m a.s.l), Sichuan province were selected, and agronomic data as well as dry matter yield were determined. …

Go to article

Forage Quality Of Cereal–Common Vetch At Different Age And Proportions, J. L. Zaragoza-Ramirez, P. A. Martinez-Hernandez, Ma. De L. Reyes-Medel Jan 2022

Forage Quality Of Cereal–Common Vetch At Different Age And Proportions, J. L. Zaragoza-Ramirez, P. A. Martinez-Hernandez, Ma. De L. Reyes-Medel

IGC Proceedings (1993-2023)

Cereal plant age at harvesting and the proportion of vetch in the harvested forage from cereal-common vetch mixtures might influence total forage quality. The objectives were to determine forage of a forage mixture cereal-vetch, from cereal harvested at two development stages and vetch at different proportion. Cereals were oats and triticale, cultivars: Chihuahua, Bicentenario and Siglo XXI, the last two were triticale; cereal development stages at harvest were: 50% flowering and hard grain. Vetch was harvested at two development stages: 100% flowering and pod formation, while vetch proportions in the forage mix were: 0, 0.25, 0.5, 0.75 and 1.0. Forage …

Go to article

Forage Accumulation And Quality Of Three Contrasting Ecotypes Of Tall Fescue (Schedonorus Arundinaceus) Managed Under Frequent Defoliation, J. Mattera, O. Scheneiter, I. Cattoni, E. Pacente, P. Barletta, O. Bertín Jan 2022

Forage Accumulation And Quality Of Three Contrasting Ecotypes Of Tall Fescue (Schedonorus Arundinaceus) Managed Under Frequent Defoliation, J. Mattera, O. Scheneiter, I. Cattoni, E. Pacente, P. Barletta, O. Bertín

IGC Proceedings (1993-2023)

In the past, tall fescue ecotypes were compared under intermediate management defoliation frequency, but now has station, Argentina (-33 ° 56 'S, -60 ° 33' W) in autumn 2016, on a typical Argiudoll soil. The treatments were cultivars representing three ecotypes of tall fescue: (i) - Mediterranean (cv. Flecha), (ii) - Intermediate (cv. Royal Q 100) and (iii) - Continental (cv. Lujan INTA). Each plot consisted of 7 rows 6.0 m long, 0.2 m apart (8.4m2 plot size) arranged in a randomized complete block design with 4 replicates. The first cut was done at the end of September when …

Go to article

Forage Production And Grazing Behaviour Of Beef Cattle In Agrosilvopastoral Systems In Brazil During The Dry Season, M. Pereira, P. Zawada, J. Werner, M. M. Macedo, R. G. Almeida, U. Dickhoefer Jan 2022

Forage Production And Grazing Behaviour Of Beef Cattle In Agrosilvopastoral Systems In Brazil During The Dry Season, M. Pereira, P. Zawada, J. Werner, M. M. Macedo, R. G. Almeida, U. Dickhoefer

IGC Proceedings (1993-2023)

We aimed at evaluating the microclimate, canopy structure, and grazing behaviour of cattle on Brachiaria sp. pastures within continuous pasture (CON), integrated crop-livestock (ICL), and crop-livestock-forestry (ICLF) systems in Brazilian dry season. Forage accumulation was monthly assessed in four paddocks per system from May to August 2019. To characterize the microclimate, air temperature and relative humidity were measured every hour and temperature-humidity index calculated. Grazing behaviour of 12 Nellore heifers per system (mean bodyweight 355 standard deviation±32.6 kg) was recorded by chewing sensors on nine continuous days (1 d adaptation + 8 d measurement) of three 15-d periods. Four animals …

Go to article

Benefits Of Cover Cropping Systems In Walnut Orchards As Sustainable Agricultural Practice, Ana Medic, Consuelo B. Baez Vega Jan 2022

Benefits Of Cover Cropping Systems In Walnut Orchards As Sustainable Agricultural Practice, Ana Medic, Consuelo B. Baez Vega

CSU Journal of Sustainability and Climate Change

In recent years walnut orchards implemented cover crops in between rows to improve soil’s quality, lessen soil’s erosion, increase organic matter, manage nutrient movement and availability, enhance water retention, and expand microbe, insect, and flora diversity. Commonly selected cover crops in California are from families Poaceae, Brassicaceae, and Fabaceae. Considerations should be made when choosing a particular cover crop mixture to enhance multiple benefits and improve sustainable practices in orchard settings. An experiment was conducted in a walnut orchard to compare functionality and benefits of three systems multi-crop, monocrop, and no vegetation cover crop system. The following components were evaluated: …

Go to article

A Closer Look At Csr Practices In Sustainable Fashion: A Guideline For Apparel Brands, Elline Deogracias, Tracie Tung, Natale Zappia Jan 2022

A Closer Look At Csr Practices In Sustainable Fashion: A Guideline For Apparel Brands, Elline Deogracias, Tracie Tung, Natale Zappia

CSU Journal of Sustainability and Climate Change

While it might be greenwashing that impedes consumers' eco-consumption, the researchers posit that this gap is also due to fashion brands’ weak CSR communication and inconsistent understanding of CSR activities. This study aims to 1) determine the ease with which consumers can navigate sustainable fashion brand websites to find corporate social responsibility (CSR) activities, and 2) construct a framework that clearly identifies CSR activities, CSR dimensions, and the business operation stages at which they occur. Website content analyses were conducted on 27 sustainable fashion brands in the United States to investigate their CSR activities. A framework was proposed to better …

Go to article

Modeling Vapor Transfer In Soil Water And Heat Simulations: A Modularized, Partially-Coupled Approach, Zhuangji Wang, Dennis Timlin, David Fleisher, Wenguang Sun, Sahila Beegum, Sanai Li, Ya Chen, Vandimalla R. Reddy, Katherine Tully, Robert Horton Jan 2022

Modeling Vapor Transfer In Soil Water And Heat Simulations: A Modularized, Partially-Coupled Approach, Zhuangji Wang, Dennis Timlin, David Fleisher, Wenguang Sun, Sahila Beegum, Sanai Li, Ya Chen, Vandimalla R. Reddy, Katherine Tully, Robert Horton

Nebraska Water Center: Faculty Publications

Coupled water and heat transfer models are widely used to analyze soil water content and temperature dynamics, evaluate agricultural management systems, and support crop growth modelling. In relatively dry soils, vapor transfer, rather than liquid water flux, becomes the main pathway for water redistribution. However, in some modularized soil simulators, e.g., 2DSOIL (Timlin et al., 1996), vapor transfer is not included, which may induce errors in soil water and heat modelling. Directly embedding vapor transfer into existing water and heat transfer modules may violate the modularized architecture of those simulators. Therefore, the objectives of this study are to design a …

Go to article

Transformers In Medical Imaging: A Survey, Fahad Shamshad, Salman Khan, Syed Waqas Zamir, Muhammad Haris Khan, Munawar Hayat, Fahad Shahbaz Khan, Huazhu Fu Jan 2022

Transformers In Medical Imaging: A Survey, Fahad Shamshad, Salman Khan, Syed Waqas Zamir, Muhammad Haris Khan, Munawar Hayat, Fahad Shahbaz Khan, Huazhu Fu

Computer Vision Faculty Publications

Following unprecedented success on the natural language tasks, Transformers have been successfully applied to several computer vision problems, achieving state-of-the-art results and prompting researchers to reconsider the supremacy of convolutional neural networks (CNNs) as de facto operators. Capitalizing on these advances in computer vision, the medical imaging field has also witnessed growing interest for Transformers that can capture global context compared to CNNs with local receptive fields. Inspired from this transition, in this survey, we attempt to provide a comprehensive review of the applications of Transformers in medical imaging covering various aspects, ranging from recently proposed architectural designs to unsolved …

Go to article

Connecting Ansatz Expressibility To Gradient Magnitudes And Barren Plateaus, Zoe Holmes, Kunal Sharma, M Cerezo, Patrick Coles Jan 2022

Connecting Ansatz Expressibility To Gradient Magnitudes And Barren Plateaus, Zoe Holmes, Kunal Sharma, M Cerezo, Patrick Coles

Faculty Publications

Parametrized quantum circuits serve as ansatze for solving variational problems and provide a flexible paradigm for the programming of near-term quantum computers. Ideally, such ansatze should be highly expressive, so that a close approximation of the desired solution can be accessed. On the other hand, the ansatz must also have sufficiently large gradients to allow for training. Here, we derive a fundamental relationship between these two essential properties: expressibility and trainability. This is done by extending the well-established barren plateau phenomenon, which holds for ansatze that form exact 2-designs, to arbitrary ansatze. Specifically, we calculate the variance in the cost …

Go to article

Cross-Disciplinary Learning Index: A Quantitative Measure Of Cross-Disciplinary Learning About Energy, Todd Haskell, Emily Borda, Andrew Boudreaux Jan 2022

Cross-Disciplinary Learning Index: A Quantitative Measure Of Cross-Disciplinary Learning About Energy, Todd Haskell, Emily Borda, Andrew Boudreaux

Physics & Astronomy

The structure of many science programs at the college level assumes that students are able to draw on and integrate ideas from multiple disciplinary contexts. However, most assessment tools focus on learning in the context of a single discipline. We describe the development and validation of an instrument to measure how well students are able to combine energy ideas from different disciplines into a coherent understanding of a phenomenon. The final version of the instrument consists of a pair of multiple-choice online assessments, along with a metric calculated from the assessment scores: the cross disciplinary learning index (CDLI). The items …

Go to article

Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew Jan 2022

Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

We report a radially and azimuthally polarized (raPol) microscope for high detection and estimation performance in single-molecule orientation-localization microscopy (SMOLM). With 5000 photons detected from Nile red (NR) transiently bound within supported lipid bilayers (SLBs), raPol SMOLM achieves 2.9 nm localization precision, 1.5° orientation precision, and 0.17 sr precision in estimating rotational wobble. Within DPPC SLBs, SMOLM imaging reveals the existence of randomly oriented binding pockets that prevent NR from freely exploring all orientations. Treating the SLBs with cholesterol-loaded methyl-β-cyclodextrin (MβCD-chol) causes NR’s orientational diffusion to be dramatically reduced, but curiously NR’s median lateral displacements drastically increase from 20.8 to …

Go to article

Future Of Winter In Northeastern North America: Climate Indicators Portray Warming And Snow Loss That Will Impact Ecosystems And Communities, Elizabeth Burakowski, Alix Contosta, Danielle Grogan, Sarah Nelson, Sarah Garlick, Nora Casson Jan 2022

Future Of Winter In Northeastern North America: Climate Indicators Portray Warming And Snow Loss That Will Impact Ecosystems And Communities, Elizabeth Burakowski, Alix Contosta, Danielle Grogan, Sarah Nelson, Sarah Garlick, Nora Casson

Faculty Publications

Winters in northeastern North America have warmed faster than summers, with impacts on ecosystems and society. Global climate models (GCMs) indicate that winters will continue to warm and lose snow in the future, but uncertainty remains regarding the magnitude of warming. Here, we project future trends in winter indicators under lower and higher climate-warming scenarios based on emission levels across northeastern North America at a fine spatial scale (1/16°) relevant to climate-related decision making. Under both climate scenarios, winters continue to warm with coincident increases in days above freezing, decreases in days with snow cover, and fewer nights below freezing. …

Go to article

Editorial: Geospace Observation Of Natural Hazards, Dimitar Ouzounov, Jann-Yenq Liu, Patrick T. Taylor, Katsumi Hattori Jan 2022

Editorial: Geospace Observation Of Natural Hazards, Dimitar Ouzounov, Jann-Yenq Liu, Patrick T. Taylor, Katsumi Hattori

Mathematics, Physics, and Computer Science Faculty Articles and Research

"This collection of technical papers aims to bring recent data from many sources into the study of natural hazards. They represent a multi-instrumental approach using both ground observations: Global Navigation Satellite System (GNSS); and Low Earth Orbiting Electromagnetic (LEO EM) satellites missions together with Earth Observations (EO), which could reveal new information. Results from latest satellite missions, [(NPP/NASA/NOAA(US), CENTINEL, Swarm/ESA (EU), HIMAWARI (JMA, Japan), FORMOSAT-5 (Taiwan, August 2017), CSES1 (China/Italy, Feb 2018), and FORMOSAT-7/COSMIC-2 (Taiwan/United States, May 2019)], are represented in this volume."

Go to article

An Empirical Study On The Efficacy Of Evolutionary Algorithms For Automated Neural Architecture Search, Andrew D. Cuccinello Jan 2022

An Empirical Study On The Efficacy Of Evolutionary Algorithms For Automated Neural Architecture Search, Andrew D. Cuccinello

Theses and Dissertations

The configuration and architecture design of neural networks is a time consuming process that has been shown to provide significant training speed and prediction improvements. Traditionally, this process is done manually, but this requires a large amount of expert knowledge and significant investment of labor. As a result it is beneficial to have automated ways to optimize model architectures. In this thesis, we study the use of evolutionary algorithm for neural architecture search (NAS). Moreover, we investigate the effect of integrating evolutionary NAS into deep reinforcement learning to learn control policy for ATARI game playing. Empirical classification results on the …

Go to article

Farmers’ Perceptions On Different Forage Types In Southern Highlands Of Tanzania, B. Nzogela, S. W. Mwendia, A. J. Mwilawa, J. Kizima, J. Bwire, A. O. Notenbaert Jan 2022

Farmers’ Perceptions On Different Forage Types In Southern Highlands Of Tanzania, B. Nzogela, S. W. Mwendia, A. J. Mwilawa, J. Kizima, J. Bwire, A. O. Notenbaert

IGC Proceedings (1993-2023)

Feed and forages take the bulk of inputs required in livestock production. Inadequate forages in quality and quantity in sub-Saharan Africa is responsible for low livestock productivity. Addressing livestock feed requirements presents quick wins in livestock productivity compared to breeding and health. In a Climate Smart Dairy project implemented in Tanzania, we demontrated several forage options to farmers including, two cultivars of Pennisetum purpureum, two Urochloa hybrids, Chrloris gayana and Tripsacum andersonii (control). Where applicable, the grasses were intercropped with either one of the following forage legume, Desmodium intortum, Lablab purpureus or Stylosanthes guiyanensis. Fourteen forage treaments …

Go to article

Examining The Impact Of Patch Burning On Livestock Grazing Patterns In Edwards Plateau, Texas, W. G. Gao, J. P. A. Angerer, X. B. W. Wu, D. T. Tolleson Jan 2022

Examining The Impact Of Patch Burning On Livestock Grazing Patterns In Edwards Plateau, Texas, W. G. Gao, J. P. A. Angerer, X. B. W. Wu, D. T. Tolleson

IGC Proceedings (1993-2023)

Production of sheep, goat, and cattle are major agricultural enterprises on West Texas rangelands, especially in the Edwards Plateau. In this region, the use of fire as a management tool was suppressed until recently. Although previous studies have been conducted to evaluate cattle use of burned versus unburned patches, there has been a lack of studies where combinations of livestock species grazing together on patch burned areas have been evaluated. The objective of this study is to examine grazing patterns of cattle, sheep and goats, both spatially and temporally, on areas where patch burning has been implemented. The study site …

Go to article

Evaluation Of Morphogenesis And Yield Of Three Pennisetum Purpureum Varieties In South-West, Nigeria, Victoria O. A. Ojo, T. A. Adeyemi, D. K. Oyaniran, G. A. Akinade, Olufemi S. Onifade Jan 2022

Evaluation Of Morphogenesis And Yield Of Three Pennisetum Purpureum Varieties In South-West, Nigeria, Victoria O. A. Ojo, T. A. Adeyemi, D. K. Oyaniran, G. A. Akinade, Olufemi S. Onifade

IGC Proceedings (1993-2023)

This experiment, conducted at the Federal University of Agriculture, Abeokuta, Nigeria evaluated the morphogenesis of three varieties of Pennisetum purpureum used in this study, which were the local, purple, and FI variety at different stages of growth. The plants were established through vegetative plant parts (stems) sourced from a previously established plot and planted using 1 m × 1 m spacing on plots measuring 4 m × 5 m. The plants were fertilized with split doses of poultry manure at 4 t/ha (equivalent to 120 kg N/ha). The experiment was laid out as a Randomized Complete Block Design. Data on …

Go to article

Effects Of Stages Of Growth On Dry Matter Yield And Nutrient Composition Of Red Clover In The Year Of Establishment In Jos, Plateau State, Nigeria, T. T. Akpensuen, J. T. Amodu, O. A. T. Namo, R. J. Tanko Jan 2022

Effects Of Stages Of Growth On Dry Matter Yield And Nutrient Composition Of Red Clover In The Year Of Establishment In Jos, Plateau State, Nigeria, T. T. Akpensuen, J. T. Amodu, O. A. T. Namo, R. J. Tanko

IGC Proceedings (1993-2023)

An experiment was conducted in Jos, Nigeria to evaluate the effects of stages of growth on dry matter yield and nutrient composition of Red clover (Trifolium pratense var. AberClaret) in the year of establishment. The treatments were five (5) stages of growth (5, 9, 13, 17 and 21) weeks after sowing (WAS). The five stages of growth were replicated five times in a Latin Square Design. The land was divided into twenty five plots of 3 m X 3 m each. The spacing between each plot was 1m along the rows and columns. Growth components and DM yield were …

Go to article

Optimal Transport For Causal Discovery, Ruibo Tu, Kun Zhang, Hedvig Kjellström, Cheng Zhang Jan 2022

Optimal Transport For Causal Discovery, Ruibo Tu, Kun Zhang, Hedvig Kjellström, Cheng Zhang

Machine Learning Faculty Publications

To determine causal relationships between two variables, approaches based on Functional Causal Models (FCMs) have been proposed by properly restricting model classes; however, the performance is sensitive to the model assumptions, which makes it difficult to use. In this paper, we provide a novel dynamical-system view of FCMs and propose a new framework for identifying causal direction in the bivariate case. We first show the connection between FCMs and optimal transport, and then study optimal transport under the constraints of FCMs. Furthermore, by exploiting the dynamical interpretation of optimal transport under the FCM constraints, we determine the corresponding underlying dynamical …

Go to article

Quantum Capacitance Investigation Of Different Tas2 Polymorphs For Energy Storage Applications – First Principles Study, Mahmoud Elattar Jan 2022

Quantum Capacitance Investigation Of Different Tas2 Polymorphs For Energy Storage Applications – First Principles Study, Mahmoud Elattar

Theses and Dissertations

Energy is an essential requirement, which has a growing demand due to the growth of population and the world transformation into electronic. More than 70% of energy resources are fossil-fuel based which has an environmental impact due to the CO2 emissions. Energy hubs for Fossil-fuel to electric energy conversion, controlled CO2 emissions processing units, and energy storage system are key factors for a smooth transition to green energy without lack of energy supplies, where electrical energy storage systems (ESS) are key enablers to achieve that. One of the effective components which determines the ESS efficiency is the electrode …

Go to article

Silver Bow Creek Butte Area Npl Site 4th Quarter 2022 Butte Priority Soils Operable Unit Interim Site-Wide Surface Water Monitoring Data Report. Consent Decree- Civil Action No. Cv 89-039-Bu-She, Josh Bryson Jan 2022

Silver Bow Creek Butte Area Npl Site 4th Quarter 2022 Butte Priority Soils Operable Unit Interim Site-Wide Surface Water Monitoring Data Report. Consent Decree- Civil Action No. Cv 89-039-Bu-She, Josh Bryson

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

Go to article

Affect Graphing: Leveraging Graphical Representations In The Study Of Students’ Affect In Mathematics, V. Rani Satyam, Younggon Bae, John P. Smith Iii, Mariana Levin Jan 2022

Affect Graphing: Leveraging Graphical Representations In The Study Of Students’ Affect In Mathematics, V. Rani Satyam, Younggon Bae, John P. Smith Iii, Mariana Levin

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

Affect (e.g., beliefs, attitudes, emotions) plays a crucial role in mathematics learning, but reliance on verbal and written responses (from surveys, interviews, etc.) limits students’ expression of their affective states. As a complement to existing methods that rely on verbal reports, we explore how graphing can be used to study affect during mathematical experiences. We analyze three studies that used graphing to represent, stimulate recall, and reflect on affect. In each, students were asked to draw their perception of an affective construct, such as confidence or intensity of emotion, against time. The studies differed in participant populations, target affect, timescales …

Go to article

Effects Of Maturity And Drying Method On The Nutritive Value Of Tropical Grasses In Nicaragua, Rocky Lemus, R. Van Der Hoek, Y. C. Newman, M. Mena, K. A. Albrecht Jan 2022

Effects Of Maturity And Drying Method On The Nutritive Value Of Tropical Grasses In Nicaragua, Rocky Lemus, R. Van Der Hoek, Y. C. Newman, M. Mena, K. A. Albrecht

IGC Proceedings (1993-2023)

Tropical grasses are key components for both grazing and conserved forages in sustainable livestock systems (beef and dairy) in Central America. The objective of the study was to evaluate grasses used in Nicaragua and their nutritive value contribution as preserved forage during the dry season under different drying methods. Five tropical bunch grasses (Andropogon gayanus, Hyparrheniarufa, Urochloabrizantha, Megathyrsus maximus, and Cenchruspurpureus) were sampled across different farms in Nicaragua in 2014 and 2015 using three replications. Forage samples were collected at 2, 4, 6, and 8-wk maturity as well as season long samples. Samples drying …

Go to article

Effects Of Harvest Frequency On Yield And Self-Thinning In Irrigated Orchardgrass (Dactylis Glomerata L.) In Oregon, Usa, G. Jones Jan 2022

Effects Of Harvest Frequency On Yield And Self-Thinning In Irrigated Orchardgrass (Dactylis Glomerata L.) In Oregon, Usa, G. Jones

IGC Proceedings (1993-2023)

Persistence is an important factor in the economic management of perennial grass swards. Frequent harvest is occasionally attributed to poor stand persistence, but self-thinning theory indicates that infrequent harvest should cause swards to thin as tillers compete for light. This experiment aimed to demonstrate and qualify self-thinning in orchardgrass managed under differing harvest frequencies. Orchardgrass was planted in September 2018 and then clipped, fertilized and divided into experimental units in March 2019. Plots were randomly assigned one of four harvest frequency treatments (n = 5): No harvest, one harvest, two harvests, and four harvests. Irrigation water and fertilizer were …

Go to article

State And Transition Models In Space And Time – Using Stms To Understand Broad Patterns Of Ecosystem Change In Iceland, I. C. Barrio, D. S. Hik, T. A. Mulloy, J. Thorsson, K. Svavarsdóttir, B. Marteinsdóttir, I. S. Jónsdóttir Jan 2022

State And Transition Models In Space And Time – Using Stms To Understand Broad Patterns Of Ecosystem Change In Iceland, I. C. Barrio, D. S. Hik, T. A. Mulloy, J. Thorsson, K. Svavarsdóttir, B. Marteinsdóttir, I. S. Jónsdóttir

IGC Proceedings (1993-2023)

Managing ecological systems sustainably requires a deep understanding of ecosystem structure and the processes driving their dynamics. Conceptual models can lead to improved management, by providing a framework for organizing knowledge about a system and identifying the causal agents of change. We developed state-and-transition models (STMs) to describe landscape changes in Iceland over three historical periods with different human influence, from pre-settlement to present days. Our models identified the set of possible states, transitions and thresholds in these ecosystems and their changes over time. To illustrate the use of these models for predicting and improving management interventions, we applied our …

Go to article

Soil Water Movement In A Watershed In The Chilean Patagonia, J. Ivelic-Sáez, P. Cisternas, J. Dörner, J. Arumí, J. Valenzuela, E. Muñoz, S. Valle, H. Alonso, R. López, H. Uribe Jan 2022

Soil Water Movement In A Watershed In The Chilean Patagonia, J. Ivelic-Sáez, P. Cisternas, J. Dörner, J. Arumí, J. Valenzuela, E. Muñoz, S. Valle, H. Alonso, R. López, H. Uribe

IGC Proceedings (1993-2023)

Magallanes region, located southern Chile, contains about 1.9 million sheep heads, in about 5 million hectares of rangelands. However, forage production is concentrated in small wetlands meadows called locally “Vegas” that only represent about 300.000 hectares. Those ecosystems that sustain patagonian ranches, produce 20 times more forage biomass than the surrounding natural rangelands. Patagonian vegas have concave topography with a hydrophyte (wet) center, and mesic slopes and xeric highlands of Festuca gracillima. Although the moisture content is controled by topography, there is scarce information about the movement of water through this concave topography. Also, the spatial variability of the …

Go to article

Simple Guidelines For Deciding When Soil Variability Does – And Doesn’T – Matter For Rangeland Management And Restoration, Jeff E. Herrick, J. Maynard, B. Bestelmeyer, A. Ganguli, J. Glover, K. Johnson, D. Kimiti, J. Neff, G. Peacock, J. Peters, S. Salley, P. Shaver, K. Shepherd, Z. Stewart, R. Van Den Bosch Jan 2022

Simple Guidelines For Deciding When Soil Variability Does – And Doesn’T – Matter For Rangeland Management And Restoration, Jeff E. Herrick, J. Maynard, B. Bestelmeyer, A. Ganguli, J. Glover, K. Johnson, D. Kimiti, J. Neff, G. Peacock, J. Peters, S. Salley, P. Shaver, K. Shepherd, Z. Stewart, R. Van Den Bosch

IGC Proceedings (1993-2023)

“Rangelands in most parts of the world are relatively homogenous and can be managed uniformly at the landscape scale” or “rangelands are extremely diverse and require different approaches even at the landscape scale.” Both statements are made frequently by rangelands scientists and managers. Both are correct. Whether or not it is worthwhile to consider soil variability when planning management and restoration at the landscape scale depends on objectives, location, and the management or restoration strategies under consideration. Together these factors determine whether outcomes are likely to be different at different locations in the landscape, and whether those outcomes can be …

Go to article

First Prev Next Last