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 69391 - 69420 of 294582

Full-Text Articles in Physical Sciences and Mathematics

Treatment Selection Using Prototyping In Latent-Space With Application To Depression Treatment, Akiva Kleinerman, Ariel Rosenfeld, David Benrimoh, Robert Fratila, Caitrin Armstrong, Joseph Mehltretter, Eliyahu Shneider, Amit Yaniv-Rosenfeld, Jordan Karp, Charles F. Reynolds, Gustavo Turecki, Adam Kapelner Nov 2021

Treatment Selection Using Prototyping In Latent-Space With Application To Depression Treatment, Akiva Kleinerman, Ariel Rosenfeld, David Benrimoh, Robert Fratila, Caitrin Armstrong, Joseph Mehltretter, Eliyahu Shneider, Amit Yaniv-Rosenfeld, Jordan Karp, Charles F. Reynolds, Gustavo Turecki, Adam Kapelner

Publications and Research

Machine-assisted treatment selection commonly follows one of two paradigms: a fully personalized paradigm which ignores any possible clustering of patients; or a sub-grouping paradigm which ignores personal differences within the identified groups. While both paradigms have shown promising results, each of them suffers from important limitations. In this article, we propose a novel deep learning-based treatment selection approach that is shown to strike a balance between the two paradigms using latent-space prototyping. Our approach is specifically tailored for domains in which effective prototypes and sub-groups of patients are assumed to exist, but groupings relevant to the training objective are not …


Soil Accretion And Mass Accumulation In A Scrub And Fringe Mangrove Forest In Biscayne Bay, Florida, Jessica A. Jacobs Nov 2021

Soil Accretion And Mass Accumulation In A Scrub And Fringe Mangrove Forest In Biscayne Bay, Florida, Jessica A. Jacobs

USF Tampa Graduate Theses and Dissertations

This study estimated soil accretion and mass (organic carbon (OC), total nitrogen (TN), and total soil) accumulation in a scrub and fringe mangrove forest in Biscayne Bay, FL, to assess how forests of different morphologies (scrub vs. fringe) have kept pace with recently accelerating rates of sea-level rise. Accretion rates (AR) were estimated using the Constant Initial Concentration (CIC) model of lead-210 deposition and it was determined that the scrub forest has accreted at 1.3 ± 0.2 mm yr-1 over 75 years and the fringe forest at 2.8 ± 0.4 mm yr-1 over 92 years. The fringe forest estimate met …


Managing Incomplete Data In The Patient Discharge Summary To Support Correct Hospital Reimbursements, Fadi Naser Eddin Nov 2021

Managing Incomplete Data In The Patient Discharge Summary To Support Correct Hospital Reimbursements, Fadi Naser Eddin

USF Tampa Graduate Theses and Dissertations

The patient discharge summary is a document that conveys the patient's story to other healthcare practitioners, external users, and, most importantly from a financial perspective, health insurers. A defect or incompleteness in the patient's discharge summary will result in delays in the collection process through denial of the entire or partial reimbursement claim or, in the best-case scenario, delay until the discharge summary issue is resolved. The purpose of this project is to address the issue of the incompleteness of discharge summary from the perspective of healthcare providers, with the goal of understanding, diagnosing, and intervening in the research problem. …


Single-Molecule Localization Microscopy Of 3d Orientation And Anisotropic Wobble Using A Polarized Vortex Point Spread Function, Tianben Ding, Matthew D. Lew Nov 2021

Single-Molecule Localization Microscopy Of 3d Orientation And Anisotropic Wobble Using A Polarized Vortex Point Spread Function, Tianben Ding, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Within condensed matter, single fluorophores are sensitive probes of their chemical environments, but it is difficult to use their limited photon budget to image precisely their positions, 3D orientations, and rotational diffusion simultaneously. We demonstrate the polarized vortex point spread function (PSF) for measuring these parameters, including characterizing the anisotropy of a molecule’s wobble, simultaneously from a single image. Even when imaging dim emitters (∼500 photons detected), the polarized vortex PSF can obtain 12 nm localization precision, 4°–8° orientation precision, and 26° wobble precision. We use the vortex PSF to measure the emission anisotropy of fluorescent beads, the wobble dynamics …


Experimental Analysis Of Gbm To Expand The Time Horizon Of Irish Electricity Price Forecasts, Conor Lynch, Christian O'Leary, Preetham Goving Kolar Sundareshan, Yavuz Akin Nov 2021

Experimental Analysis Of Gbm To Expand The Time Horizon Of Irish Electricity Price Forecasts, Conor Lynch, Christian O'Leary, Preetham Goving Kolar Sundareshan, Yavuz Akin

NIMBUS Articles

In response to the inherent challenges of generating cost-effective electricity consumption schedules for dynamic systems, this paper espouses the use of GBM or Gradient Boosting Machine-based models for electricity price forecasting. These models are applied to data streams from the Irish electricity market and achieve favorable results, relative to the current state-of-the-art. Presently, electricity prices are published 10 h in advance of the trade day of interest. Using the forecasting methodology outlined in this paper, an estimation of these prices can be made available one day in advance of the official price publication, thus extending the time available to plan …


Non-Adiabatic Excited State Molecular Dynamics Using Ehrenfest And Modulated X-Ray Absorption In Titania, Alexander Matthew Meyer Nov 2021

Non-Adiabatic Excited State Molecular Dynamics Using Ehrenfest And Modulated X-Ray Absorption In Titania, Alexander Matthew Meyer

LSU Doctoral Dissertations

This dissertation contains two separate sections aside from an introduction (Chapter 1): theory and methods (Chapter 2), time dependent density functional theory with Ehrenfest for excited state lifetimes in materials (Chapter 3), and simulated field modulated X-ray absorption in titania (Chapter 4).

Excited state lifetime in insulators and semiconductors can be difficult to compute using quantum chemistry due to their dense excited states. Non-radiative decay in these materials requires the use of non-adiabatic effects to dissipate energy through the means of electron-nuclear coupling such as coherent phonon generation. One method of approaching this challenge in these materials is using Ehrenfest …


California Drought Outlooks Based On Climate Change Models’ Effects On Water Availability, Lauren Lynam, Thomas Piechota Nov 2021

California Drought Outlooks Based On Climate Change Models’ Effects On Water Availability, Lauren Lynam, Thomas Piechota

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Future streamflow in California is evaluated based on eight climate projections models and the effects on water availability. The unimpaired projected streamflow for eleven California rivers, collected from Cal-Adapt, are compared with unimpaired historical flows (1950–2015) using eight climate model projections (2020–2099) identified as representative as possible future scenarios; Warm Dry RCP 4.5, Average RCP 4.5, Cool Wet RCP 4.5, Other RCP 4.5, Warm Dry RCP 8.5, Average RCP 8.5, Cool Wet RCP 8.5, and Other RCP 8.5. Projected drought deficits (or magnitudes), durations, and intensities are statistically tested against historical values to determine significance of differences between past streamflow …


Covariant Ergodic Quantum Markov Semigroups Via Systems Of Imprimitivity, Radhakrishnan Balu Nov 2021

Covariant Ergodic Quantum Markov Semigroups Via Systems Of Imprimitivity, Radhakrishnan Balu

Journal of Stochastic Analysis

No abstract provided.


Regional Expansion And Evaluation Of Potential Chemical Control For Invasive Apple Snails (Pomacea Maculata) In Southwest Louisiana, Julian M. Lucero Nov 2021

Regional Expansion And Evaluation Of Potential Chemical Control For Invasive Apple Snails (Pomacea Maculata) In Southwest Louisiana, Julian M. Lucero

LSU Master's Theses

The integration of monitoring and chemical control is an efficient strategy for managing invasive apple snails, Pomacea maculata, in the rice (Oryza sativa L.) and crawfish systems of southwest Louisiana. However, their current distribution, expansion rates, and susceptibility to chemical control methods in this area are not well known. This study evaluated the expansion of P. maculata in southwest Louisiana and assessed potential chemical control for P. maculata among toxicity assays using various application rates. The effects of potential chemical control were also assessed on a non-target species, the red swamp crawfish (Procambarus clarkii). P. maculata …


Learning From Mistakes - A Framework For Neural Architecture Search, Bhanu Garg, Li Zhang, Pradyumna Sridhara, Ramtin Hosseini, Eric P. Xing, Pengtao Xie Nov 2021

Learning From Mistakes - A Framework For Neural Architecture Search, Bhanu Garg, Li Zhang, Pradyumna Sridhara, Ramtin Hosseini, Eric P. Xing, Pengtao Xie

Machine Learning Faculty Publications

Learning from one's mistakes is an effective human learning technique where the learners focus more on the topics where mistakes were made, so as to deepen their understanding. In this paper, we investigate if this human learning strategy can be applied in machine learning. We propose a novel machine learning method called Learning From Mistakes (LFM), wherein the learner improves its ability to learn by focusing more on the mistakes during revision. We formulate LFM as a three-stage optimization problem: 1) learner learns; 2) learner re-learns focusing on the mistakes, and; 3) learner validates its learning. We develop an efficient …


Mgrre_Pureoilscouttickets_Bowen, George W._1_21127120500000, Mgrre Nov 2021

Mgrre_Pureoilscouttickets_Bowen, George W._1_21127120500000, Mgrre

Legacy Scout Tickets from Pure Oil Company

No abstract provided.


Spatial Variations Of Stochastic Noise Properties In Gps Time Series, Xiaoxing He, Michael Simon Bos, Jean-Philippe Montillet, Rui Fernandes, Timothy I. Melbourne, Weiping Jiang, Wudong Li Nov 2021

Spatial Variations Of Stochastic Noise Properties In Gps Time Series, Xiaoxing He, Michael Simon Bos, Jean-Philippe Montillet, Rui Fernandes, Timothy I. Melbourne, Weiping Jiang, Wudong Li

Geological Sciences Faculty Scholarship

The noise in position time series of 568 GPS (Global Position System) stations across North America with an observation span of ten years has been investigated using solutions from two processing centers, namely, the Pacific Northwest Geodetic Array (PANGA) and New Mexico Tech (NMT). It is well known that in the frequency domain, the noise exhibits a power-law behavior with a spectral index of around −1. By fitting various noise models to the observations and selecting the most likely one, we demonstrate that the spectral index in some regions flattens to zero at long periods while in other regions it …


Search For Active-Sterile Antineutrino Mixing Using Neutral-Current Interactions With The Nova Experiment, M. A. Acero, P. Adamson, L. Aliaga, N. Anfimov, A. Antoshkin, E. Arrieta-Diaz, L. Asquith, A. Aurisano, A. Back, C. Backhouse, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, R. Bernstein, B. Bhatnagar, B. Bhuyan, J. Bian, Roberto Petti, Et. Al. Nov 2021

Search For Active-Sterile Antineutrino Mixing Using Neutral-Current Interactions With The Nova Experiment, M. A. Acero, P. Adamson, L. Aliaga, N. Anfimov, A. Antoshkin, E. Arrieta-Diaz, L. Asquith, A. Aurisano, A. Back, C. Backhouse, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, R. Bernstein, B. Bhatnagar, B. Bhuyan, J. Bian, Roberto Petti, Et. Al.

Faculty Publications

This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51×1020 protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122±11(stat.)±15(syst.) assuming mixing only between three active flavors. No evidence for ⊽ μ → ⊽ s oscillation is observed. Interpreting this result within a …


Silver Bow Creek/Butte Area Npl Site Butte Priority Soils Operable Unit, Pioneer Technical Services, Inc. Nov 2021

Silver Bow Creek/Butte Area Npl Site Butte Priority Soils Operable Unit, Pioneer Technical Services, Inc.

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


Revisiting Darwin’S Little Pond As A Method To Liberate Phosphorus From Apatite Under Prebiotic Hadean Earth Conditions, Jennifer Lago Nov 2021

Revisiting Darwin’S Little Pond As A Method To Liberate Phosphorus From Apatite Under Prebiotic Hadean Earth Conditions, Jennifer Lago

USF Tampa Graduate Theses and Dissertations

Phosphorus is an essential element for life as we know it. Phosphorus, mainly in the form of phosphate, is key to biologic functions such as genetic material, energy production, and cellular framework. As phosphorus is key to so many important biological functions it is of no wonder the question of how phosphorus was incorporated into life initially is a fundamental question in how life began.

During this time a prebiotic phosphorus source would need to have originated in rock, as phosphorus has not volatile source on Earth. The most prevalent mineral source on a prebiotic Earth would likely have been …


Efficient Management Of Nitrogen And Phosphorus At Centralized Water Reclamation Facilities, Helene Kassouf Nov 2021

Efficient Management Of Nitrogen And Phosphorus At Centralized Water Reclamation Facilities, Helene Kassouf

USF Tampa Graduate Theses and Dissertations

A variety of process configurations are employed at municipal water reclamation facilities (WRFs), such as 5-stage Bardenpho, oxidation ditch, modified Ludzack-Ettinger (MLE) process, and sidestream recycle. However, all of these configurations face certain challenges in achieving optimum treatment of nitrogen and phosphorus. In this dissertation, the driving objectives were to: (1) quantitatively assess the fate of nitrogen and phosphorus (mass fluxes) at a treatment facility that employs biological nutrient removal, aerobic digestion, and sidestream recycle, (2) evaluate the performance of a microbial fuel cell (MFC) as a technology to remove nitrogen from sidestreams at a treatment plant that employs that …


Fighting Mass Diffusion Of Fake News On Social Media, Abdallah Musmar Nov 2021

Fighting Mass Diffusion Of Fake News On Social Media, Abdallah Musmar

USF Tampa Graduate Theses and Dissertations

Fake news has been considered one of the most challenging problems in the last few years. The effects of spreading fake news over social media platforms are widely observed across the globe as the depth and velocity of fake news reach far more than real news (Vosoughi et al., 2018). The plan for the following dissertation is to investigate the mass spread of fake news across social media and propose a framework to fight the spread of fake news by mixing preventive methods that could hinder the overall percentage of fake news sharing. We plan to create a study on …


Exploring Dft+U Parameter Space With A Bayesian Calibration Assisted By Markov Chain Monte Carlo Sampling, Pedram Tavadze, Reese Boucher, Guillermo Avendaño-Franco, Keenan X. Kocan, Sobhit Singh, Viviana Dovale-Farelo, Wilfredo Ibarra-Hernández, Matthew B. Johnson, David S. Mebane, Aldo H. Romero Nov 2021

Exploring Dft+U Parameter Space With A Bayesian Calibration Assisted By Markov Chain Monte Carlo Sampling, Pedram Tavadze, Reese Boucher, Guillermo Avendaño-Franco, Keenan X. Kocan, Sobhit Singh, Viviana Dovale-Farelo, Wilfredo Ibarra-Hernández, Matthew B. Johnson, David S. Mebane, Aldo H. Romero

Faculty & Staff Scholarship

The density-functional theory is widely used to predict the physical properties of materials. However, it usually fails for strongly correlated materials. A popular solution is to use the Hubbard correction to treat strongly correlated electronic states. Unfortunately, the values of the Hubbard U and J parameters are initially unknown, and they can vary from one material to another. In this semi-empirical study, we explore the U and J parameter space of a group of iron-based compounds to simultaneously improve the prediction of physical properties (volume, magnetic moment, and bandgap). We used a Bayesian calibration assisted by Markov chain Monte Carlo …


Athena: A Unique Radiation Environment Platform At The National Ignition Facility, Nicholas J. Quartemont, George Peterson, Colton Moran, Adib J. Samin, Buguo Wang, Charles Yeamans, Brandon Woodworth, Darren Holland, James C. Petrosky, James E. Bevins Nov 2021

Athena: A Unique Radiation Environment Platform At The National Ignition Facility, Nicholas J. Quartemont, George Peterson, Colton Moran, Adib J. Samin, Buguo Wang, Charles Yeamans, Brandon Woodworth, Darren Holland, James C. Petrosky, James E. Bevins

Faculty Publications

This paper describes the ATHENA platform, an energy tuning assembly, which was developed to spectrally shape the National Ignition Facility (NIF) deuterium–tritium fusion neutron source to a thermonuclear (fusion) plus prompt fission neutron spectrum with a capability to act as a short-pulse neutron source. This unique, otherwise inaccessible radiation environment complements existing experimental facilities and capabilities. The flexible ATHENA irradiation positions were modeled using an ensemble of Monte Carlo simulations with stochastic sampling of the nuclear cross-sections to characterize the radiation environments and uncertainty for the platform. Validation of the internal neutron spectrum produced from fielding ATHENA at NIF occurred …


Interspecific And Local Variation In Tern Chick Diets Across Nesting Colonies In The Gulf Of Maine, Keenan Yakola, Adrian Jordaan, Stephen Kress, Paula Shannon, Michelle D. Staudinger Nov 2021

Interspecific And Local Variation In Tern Chick Diets Across Nesting Colonies In The Gulf Of Maine, Keenan Yakola, Adrian Jordaan, Stephen Kress, Paula Shannon, Michelle D. Staudinger

United States Geological Survey: Staff Publications

The Gulf of Maine, USA is home to four colonial co-nesting tern species: Least Tern (Sternula antillarum), Common Tern (Sterna hirundo), Arctic Tern (Sterna paradisaea), and the federally endangered Roseate Tern (Sterna dougallii). Over three decades of visual observations of chick provisioning were compiled for a comparative dietary study in the region, including the first detailed descriptions of Least and Roseate Tern chick diets. Three prey groups comprised the majority of chick diets among tern species between 1986–2017: hake (Urophycis spp. or Enchelyopus cimbrius) 28–37% frequency of occurrence (FO), sand lance …


Association Between Neighborhood Social Deprivation And Stage At Diagnosis Among Breast Cancer Patients In South Carolina, Oluwole Adeyemi Babatunde, Whitney Zahnd Ph.D., Jan Eberth Ph.D., Andrew B. Lawson, Swann Arp Adams, Eric Adjei Boakye, Melanie S. Jefferson, Caitlin G. Allen, John L. Pearce, Hong Li, Chanita Hughes Halbert Nov 2021

Association Between Neighborhood Social Deprivation And Stage At Diagnosis Among Breast Cancer Patients In South Carolina, Oluwole Adeyemi Babatunde, Whitney Zahnd Ph.D., Jan Eberth Ph.D., Andrew B. Lawson, Swann Arp Adams, Eric Adjei Boakye, Melanie S. Jefferson, Caitlin G. Allen, John L. Pearce, Hong Li, Chanita Hughes Halbert

Faculty Publications

The purpose of this study was to examine the association between neighborhood social deprivation and individual-level characteristics on breast cancer staging in African American and white breast cancer patients. We established a retrospective cohort of patients with breast cancer diagnosed from 1996 to 2015 using the South Carolina Central Cancer Registry. We abstracted sociodemographic and clinical variables from the registry and linked these data to a county-level composite that captured neighborhood social conditions—the social deprivation index (SDI). Data were analyzed using chi-square tests, Student’s t-test, and multivariable ordinal regression analysis to evaluate associations. The study sample included 52,803 female patients …


Detecting And Reconstructing Gravitational Waves From The Next Galactic Core-Collapse Supernova In The Advanced Detector Era, Marek J. Szczepańczyk, Javier M. Antelis, Michael Benjamin, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Nov 2021

Detecting And Reconstructing Gravitational Waves From The Next Galactic Core-Collapse Supernova In The Advanced Detector Era, Marek J. Szczepańczyk, Javier M. Antelis, Michael Benjamin, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We performed a detailed analysis of the detectability of a wide range of gravitational waves derived from core-collapse supernova simulations using gravitational-wave detector noise scaled to the sensitivity of the upcoming fourth and fifth observing runs of the Advanced LIGO, Advanced Virgo, and KAGRA. We use the coherent WaveBurst algorithm, which was used in the previous observing runs to search for gravitational waves from core-collapse supernovae. As coherent WaveBurst makes minimal assumptions on the morphology of a gravitational-wave signal, it can play an important role in the first detection of gravitational waves from an event in the Milky Way. We …


10587273 Edd, Pioneer Technical Services, Inc. Nov 2021

10587273 Edd, Pioneer Technical Services, Inc.

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


The Maritime Domain Awareness Center– A Human-Centered Design Approach, Gary Gomez Nov 2021

The Maritime Domain Awareness Center– A Human-Centered Design Approach, Gary Gomez

Political Science & Geography Faculty Publications

This paper contends that Maritime Domain Awareness Center (MDAC) design should be a holistic approach integrating established knowledge about human factors, decision making, cognitive tasks, complexity science, and human information interaction. The design effort should not be primarily a technology effort that focuses on computer screens, information feeds, display technologies, or user interfaces. The existence of a room with access to vast amounts of information and wall-to-wall video screens of ships, aircraft, weather data, and other regional information does not necessarily correlate to possessing situation awareness. Fundamental principles of human-centered information design should guide MDAC design and technology selection, and …


All-Sky Search For Long-Duration Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, Richard Abbott, Thomas D. Abbott, Fausto Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Nov 2021

All-Sky Search For Long-Duration Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, Richard Abbott, Thomas D. Abbott, Fausto Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

After the detection of gravitational waves from compact binary coalescences, the search for transient gravitational-wave signals with less well-defined waveforms for which matched filtering is not well suited is one of the frontiers for gravitational-wave astronomy. Broadly classified into "short" less than or similar to 1 s and "long" greater than or similar to 1 s duration signals, these signals are expected from a variety of astrophysical processes, including non-axisymmetric deformations in magnetars or eccentric binary black hole coalescences. In this work, we present a search for long-duration gravitational-wave transients from Advanced LIGO and Advanced Virgo's third observing run from …


Detecting And Reconstructing Gravitational Waves From The Next Galactic Core-Collapse Supernova In The Advanced Detector Era, Marek J. Szczepańczyk, Javier M. Antelis, Michael Benjamin, Marco Cavaglia, Dorota Gondek-Rosińska, Travis Hansen, Soma Mukherjee, Gaukhar Nurbek, Satzhan Sitmukhambetov, Oscar Valdez Nov 2021

Detecting And Reconstructing Gravitational Waves From The Next Galactic Core-Collapse Supernova In The Advanced Detector Era, Marek J. Szczepańczyk, Javier M. Antelis, Michael Benjamin, Marco Cavaglia, Dorota Gondek-Rosińska, Travis Hansen, Soma Mukherjee, Gaukhar Nurbek, Satzhan Sitmukhambetov, Oscar Valdez

Physics & Astronomy Faculty Publications

We performed a detailed analysis of the detectability of a wide range of gravitational waves derived from core-collapse supernova simulations using gravitational-wave detector noise scaled to the sensitivity of the upcoming fourth and fifth observing runs of the Advanced LIGO, Advanced Virgo, and KAGRA. We use the coherent WaveBurst algorithm, which was used in the previous observing runs to search for gravitational waves from core-collapse supernovae. As coherent WaveBurst makes minimal assumptions on the morphology of a gravitational-wave signal, it can play an important role in the first detection of gravitational waves from an event in the Milky Way. We …


Evaluation Of Paspalum Spp. With Adaptation To Poorly Drained Soils In The Tropical Americas, Michael Peters, B. Hincapié, P. Avila, C. E. Lascano Nov 2021

Evaluation Of Paspalum Spp. With Adaptation To Poorly Drained Soils In The Tropical Americas, Michael Peters, B. Hincapié, P. Avila, C. E. Lascano

IGC Proceedings (1977-2023)

A collection of Paspalum accessions obtained from Brazil was tested for their adaptation to poorly drained soils. Three accessions were selected based on their DM production and nutritive value. Productivity and quality of these three accessions was stable over the periods of maximum and minimum rainfall, giving potential for continuous forage supply throughout the year in the tropical Americas. Grazing trials for the selected accessions are underway.


Intake Characteristics And Performance Of Contrasting Grass Varieties Continuously Stocked With Sheep, R. J. Orr, J. E. Cook, R. A. Champion, A. J. Rook Nov 2021

Intake Characteristics And Performance Of Contrasting Grass Varieties Continuously Stocked With Sheep, R. J. Orr, J. E. Cook, R. A. Champion, A. J. Rook

IGC Proceedings (1977-2023)

Fifteen intermediate-heading perennial ryegrass (Lolium perenne) varieties were grazed by sheep under continuous variable stocking management. Mean daily grass dry matter intake per ewe was positively correlated with liveweight gain per ewe (r = 0.63) and per ha (r = 0.58) over an 8-month grazing season. Daily intake was not correlated with grazing time (r = 0.12) but was positively correlated with instantaneous dry matter intake rate (r = 0.75). Breeding varieties with high intake rate characteristics should allow increases in the contribution of grazed grass to grassland-based livestock farming. There is now a …


Drought Tolerance Of Interspecific Hybrids Between Trifolium Repens And Trifolium Ambiguum, A. H. Marshall, M. T. Abberton, T. P. T. Michaelson-Yeates, I. Rhodes, A. Williams Nov 2021

Drought Tolerance Of Interspecific Hybrids Between Trifolium Repens And Trifolium Ambiguum, A. H. Marshall, M. T. Abberton, T. P. T. Michaelson-Yeates, I. Rhodes, A. Williams

IGC Proceedings (1977-2023)

Hybrids between the stolonifeous white clover (Trifolium repens L., 2n=4x=32) and rhizomatous Caucasian clover (T. ambiguum M.Bieb, 2n=4x=32) have been produced. A backcross 2 (BC2) generation with white clover as the recurrent parent combines the growth habit of both parent species with the objective of increasing the persistency of large leaved T. repens varieties under grazing. T. ambiguum is more drought tolerant than T. repens. The drought tolerance of the hybrids in comparison with the parental species was compared in deep soil bins over a four week drought cycle. Soil moisture content, leaf relative water content …


Variability For Nitrogen And Phosphorus Uptake Among Timothy Genotypes, Réal Michaud, Gilles Bélanger, A. Brégard Nov 2021

Variability For Nitrogen And Phosphorus Uptake Among Timothy Genotypes, Réal Michaud, Gilles Bélanger, A. Brégard

IGC Proceedings (1977-2023)

Cultivars of timothy (Phleum pratense L.) with high N and P use efficiencies are required to reduce costs of production and risks of N and P pollution, and to meet the nutrition requirements of high producing animals. This field study aimed at comparing, (under three N rates) the relationship between DM yield, N uptake, and P uptake of 27 timothy half-sib families, plus the cultivar Champ as a control (Dry matter yield), N and P uptake increased with increasing N rates. Genotypes also differed for DM yield, N and P uptake. For a given DM yield, the genotypes had …