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Full-Text Articles in Physical Sciences and Mathematics

Sward Characteristics Of A Diploid And Tetraploid Cultivar Of Perennial Ryegrass As Measured By Different Sampling Techniques, J H. Neuteboom, E A. Lantinga, H Schlepers, L 'T Mannetje Aug 2024

Sward Characteristics Of A Diploid And Tetraploid Cultivar Of Perennial Ryegrass As Measured By Different Sampling Techniques, J H. Neuteboom, E A. Lantinga, H Schlepers, L 'T Mannetje

IGC Proceedings (1993-2023)

In a grazing experiment with monocultures of 2 perennial ryegrass (Lolium perenne L.) cultivars it was found that over a 6-year period the tiller density of the tetraploid Condesa was on average 27% lower than that of the diploid Wendy. The lower tiller density of Condesa went along with a more open sward structure and higher weed proportions after 6 years, Sward structure was suitably characterised by means of absence frequency estimations of rooted perennial ryegrass tillers from concentric sampling quadrats.


Defoliation Frequency And Intensity Of Arrhenathherum Elatius, G H. D'Angelo, E B. Postulka, L Ferrari Jun 2024

Defoliation Frequency And Intensity Of Arrhenathherum Elatius, G H. D'Angelo, E B. Postulka, L Ferrari

IGC Proceedings (1993-2023)

This experiment was conducted with the aim of studying whether the frequency and intensity of defoliation of the temperate grass fromental (Arrhenatherum elatius (L.) Presl.) affected its total dry matter (DM)/ha yield as well as the seasonal distribution of forage. Plots were seeded in 1988 and data collected from 1989 to 1991. Two frequencies and two intensities of defoliation were combined in a two factor randomized complete block design with six replications. Treatment plots were cut each year from early autumn to late spring. ANVA, Tukey and Dunnett tests were applied to find out differences between treatments and between …


Factors Associated With Acoustic Bat Presence During Spring Emergence In The Appalachian Mountains Of Western Virginia, Emily Kirk Pody Jan 2024

Factors Associated With Acoustic Bat Presence During Spring Emergence In The Appalachian Mountains Of Western Virginia, Emily Kirk Pody

Theses, Dissertations and Capstones

Studies of threats that bats face during hibernation have increased in response to white-nose syndrome (WNS), a fungal disease that has ravaged North American bat populations. However, impacts of WNS on bat ecology during spring emergence, when bats are potentially recovering from infection and allocating resources for reproduction, is relatively understudied. As more bat species become listed at the federal and state level, the need to understand the factors associated with spring emergence is critical for improving conservation guidelines and habitat management practices. Acoustic monitoring is an efficient method for monitoring bat presence for prolonged periods of time, giving biologists …


The Relationship Between Biofouling Adhesion And Frequency Of Mechanical Cleaning To Control The Recruitment To Clear Coatings, Dylan Thomas Eggers Dec 2023

The Relationship Between Biofouling Adhesion And Frequency Of Mechanical Cleaning To Control The Recruitment To Clear Coatings, Dylan Thomas Eggers

Theses and Dissertations

There is a need to control biofouling on sensors and transparent windows in the marine environment. Clear silicone coatings offer a method to reduce the adhesion strength of marine organisms to the surface, however, these also require mechanical cleaning to maintain the surfaces free of fouling. This research evaluated the performance of eighty seven formulations and took the top two candidates to investigate a) the frequencies of wiping required by a brush to maintain two coatings and uncoated glass surfaces free of fouling and b) the effects of clear silicone coatings fouling release properties on required frequencies. The panels were …


Alternative Perennial Legumes On Acid Soils In Southern New South Wales, Australia, Guangdi Li, Richard C. Hayes, B. S. Dear Sep 2020

Alternative Perennial Legumes On Acid Soils In Southern New South Wales, Australia, Guangdi Li, Richard C. Hayes, B. S. Dear

IGC Proceedings (1993-2023)

No abstract provided.


Defoliation Impact On The Above And Belowground Productivity Of Festuca Arundinaceae Schreb, Hennie A. Snyman, P. J. Malan Apr 2020

Defoliation Impact On The Above And Belowground Productivity Of Festuca Arundinaceae Schreb, Hennie A. Snyman, P. J. Malan

IGC Proceedings (1993-2023)

The main objective of pasture management is to maximize plant productivity and ensure sustainable animal performance, without inducing pasture deterioration. Many researchers indicated that plant survival and sustainable production is a function of seedbed preparation, irrigation and defoliation, with defoliation having the largest impact on plant persistence (Fulkerson and Donaghy, 2001). The net effect of defoliation (degree of intensity and frequency) can therefore either be beneficial or detrimental to survival and productivity of a pasture. The aim of this study was to quantify the impact of different intensities and frequencies of defoliation on above- and belowground phytomass production of the …


Effect Of Supplementation Frequency On Forage Utilization By Heifers Grazing A Tropical Pasture During The Dry Season, José Augusto Imaz, D. Dos Santos, O. Hernández, A. Radrizzani, J. I. Arroquy Mar 2020

Effect Of Supplementation Frequency On Forage Utilization By Heifers Grazing A Tropical Pasture During The Dry Season, José Augusto Imaz, D. Dos Santos, O. Hernández, A. Radrizzani, J. I. Arroquy

IGC Proceedings (1993-2023)

In tropical pasture, low quality and availability forage during the dry season can limit the cattle intake. Energetic and protein supplementation is a viable practice to improve feed intake and animal performance. Previous studies have shown that infrequent protein supplementation decreases feeding cost achieving similar performance compared with every day supplementation (Farmer et al., 2004). Even though infrequent protein supplementation has been widely studied, little research has been carried out on infrequent energetic supplementation, especially its effect on pasture utilization. Some evidence indicates that negative effects on forage use at low levels of infrequent supplementation (Beaty et al., 1994). …


Effect Of Enclosure On Botanical Composition, Forage Biomass And Other Range Productivity Parameters In A Semi-Arid Area Of El-Khuwei Locality, North Kordofan State, Sudan, Mohammed Abdelkreim, Babo Fadlalla Jan 2020

Effect Of Enclosure On Botanical Composition, Forage Biomass And Other Range Productivity Parameters In A Semi-Arid Area Of El-Khuwei Locality, North Kordofan State, Sudan, Mohammed Abdelkreim, Babo Fadlalla

IGC Proceedings (1993-2023)

Animal production in North Kordofan State is mainly traditional depending on natural rangeland (Cook and Fadlalla 1987), (DHP, 1998). The State has an area of about 25 million ha of which 14.5 million ha is rangeland (Africover 2004). It is among the leading Sudanese States in animal and range resources. It contains more than 13 million heads of sheep, goats, camels and cattle (IFAD 2011). This paper deals with the effect of enclosure and stage of maturity on botanical composition, forage biomass production and other range productivity parameters in this semi-arid area.


El Nino Southern Oscillation (Enso) Enhances Co2 Exchange Rates In Freshwater Marsh Ecosystems In The Florida Everglades, Sparkle L. Malone, Christina L. Staudhammer, Steven F. Oberbauer, Paulo Olivas, Michael G. Ryan, Jessica L. Schedlbauer, Henry W. Loescher, Gregory Starr Dec 2014

El Nino Southern Oscillation (Enso) Enhances Co2 Exchange Rates In Freshwater Marsh Ecosystems In The Florida Everglades, Sparkle L. Malone, Christina L. Staudhammer, Steven F. Oberbauer, Paulo Olivas, Michael G. Ryan, Jessica L. Schedlbauer, Henry W. Loescher, Gregory Starr

Biology Faculty Publications

No abstract provided.


Grass And Canada Goldenrod (Solidago Canadensis) Competition And Implications For Management In The Northern Tallgrass Prairie, Alexander J. Smart, Gary E. Larson, Peter J. Bauman Jun 2012

Grass And Canada Goldenrod (Solidago Canadensis) Competition And Implications For Management In The Northern Tallgrass Prairie, Alexander J. Smart, Gary E. Larson, Peter J. Bauman

The Prairie Naturalist

Canada goldenrod (Solidago canadensis L.) is a native perennial forb that can form dense clonal patches and become weedy in pastures of the Northern Tallgrass Prairie Ecoregion. Our objectives were to determine 1) the competitive effects between Canada goldenrod and grass, 2) the relationship between Canada goldenrod stem density and grass biomass, and 3) the distribution of Canada goldenrod stem density at the pasture scale. We used regression analysis to develop a relationship between Canada goldenrod stem density and grass biomass. Additionally, we estimated the frequency distribution of Canada goldenrod stem density categories using three evenly distributed 100 × 100-m …


Direct Imaging Of Lipid-Ion Network Formation Under Physiological Conditions By Frequency Modulation Atomic Force Microscopy, Michael J. Higgins, Suzi P. Jarvis, Takeshi Fukuma Jan 2007

Direct Imaging Of Lipid-Ion Network Formation Under Physiological Conditions By Frequency Modulation Atomic Force Microscopy, Michael J. Higgins, Suzi P. Jarvis, Takeshi Fukuma

Faculty of Science - Papers (Archive)

Various metal cations in physiological solutions interact with lipid headgroups in biological membranes, having an impact on their structure and stability, yet little is known about the molecular-scale dynamics of the lipid-ion interactions. Here we directly investigate the extensive lipid-ion interaction networks and their transient formation between headgroups in a dipalmitoylphosphatidylcholine bilayer under physiological conditions. The spatial distribution of ion occupancy is imaged in real space by frequency modulation atomic force microscopy with sub-Angstrom resolution.


Quantitative Force Measurements In Liquid Using Frequency Modulation Atomic Force Microscopy, Suzi P. Jarvis, S. Akita, Takayuki Uchihashi, John E. Sader, Y. Nakayama, Michael J. Higgins, S Yasuda Jan 2004

Quantitative Force Measurements In Liquid Using Frequency Modulation Atomic Force Microscopy, Suzi P. Jarvis, S. Akita, Takayuki Uchihashi, John E. Sader, Y. Nakayama, Michael J. Higgins, S Yasuda

Faculty of Science - Papers (Archive)

The measurement of short-range forces with the atomic force microscope (AFM) typically requires implementation of dynamic techniques to maintain sensitivity and stability. While frequency modulation atomic force microscopy (FM-AFM) is used widely for high-resolution imaging and quantitative force measurements in vacuum, quantitative force measurements using FM-AFM in liquids have proven elusive. Here we demonstrate that the formalism derived for operation in vacuum can also be used in liquids, provided certain modifications are implemented. To facilitate comparison with previous measurements taken using surface forces apparatus, we choose a model system (octamethylcyclotetrasiloxane) that is known to exhibit short-ranged structural ordering when confined …


Van Der Waals Interactions Of Carbon Monoxide, Gregory A. Parker, Russell T. Pack Mar 1976

Van Der Waals Interactions Of Carbon Monoxide, Gregory A. Parker, Russell T. Pack

Faculty Publications

Pade approximant methods and experimental frequency dependent polarizabilities are used to calculate reliable van der Waals C6 coefficients for the interaction of CO with He, Ne, Ar, Kr, Xe, H, Li, Na, K, Rb, Cs, H2, N2, O2, CO2, and CO. Error bounds are given for the C6 coefficients and for the CO oscillator strength sums.