Physical Sciences and Mathematics Commons^™

Mixed Fattening Of Steers And Lambs On Improved Grasslands In Uruguay: Ii. Animal Performance And Productivity, D. F. Risso, Fabio Montossi, E. J. Berretta, R. Cuadro, I. De Barbieri, R. San Julián, A. Dighiero, A. Zarza

IGC Proceedings (1997-2023)

In cow-calf operations in Uruguay, mixed cattle and sheep grazing on rangelands is predominant, while fattening is a specialised process. Within certain limits of the lamb/steer ratio and stocking rate, a complementary grazing effect occurs under mixed grazing, improving net results (Nolan & Connolly, 1977; Risso et al., 2002). These trials characterise animal performance under such management.

Farm Performance From Holstein-Friesian Cows Of Three Genetic Strains On Grazed Pasture, K. A. Macdonald, B. S. Thorrold, C. B. Glassey, J. A. S. Lancaster, G. A. Verkerk, J. E. Pryce, C. W. Holmes

IGC Proceedings (1997-2023)

Dairy selection objectives and farm production systems in USA and Europe are different from those in New Zealand (NZ). The use of overseas semen in NZ in the last 20 years has changed the genetics of the former NZ Holstein-Friesian (HF) strain. This trial was designed to demonstrate the genetic progress in the NZ HF dairy herd in the last 25 years and how high production potential North American HF cows perform under pasture-based feeding systems.

Effects Of Rumen Fill On Intake And Milk Production In Dairy Cows Fed Perennial Ryegrass, A. V. Chaves, A. Boudon

IGC Proceedings (1997-2023)

Physical limitation often limits dry matter intake (DMI) of high producing cows or cows fed high forage diets. The extent to which DMI is regulated by distention in the rumen depends upon the cow’s energy requirement and filling effects of the diet offered (Allen, 2000). The objective here was to challenge middle lactation dairy cows with rumen fill (rumen inert bulk – RIB) feeding ryegrass fresh cut (indoors) or grazed to determine whether RIB affects intake and milk production.

Performance Of Meat Goats Grazing Winter Annual Grasses In The Piedmont Of The Southeastern Usa, J-M. Luginbuhl, J. P. Mueller

IGC Proceedings (1997-2023)

In the Southeastern United States, meat goats (Capra hircus hircus) are becoming increasingly important contributors to the income of many small producers. Meat goats perform well in grazing situations if grazing management practices match their grazing behavior. Nevertheless, little research data are available from the region specifically directed toward forage feeding programs for goats reared for meat production. Hart et al. (1993) reported that growing Alpine, Angora and Nubian kids grazed on high quality Triticum aestivum forage gained 50 g/d, whereas Kiesling et al. (1994) reported gains ranging from 65 to 141 g/d in growing Angora …

Quality Of Ammoniated Brachiaria Decumbens Hay, L. O. Fernandes, Ricardo A. Reis, L. R. A. Rodrigues

IGC Proceedings (1997-2023)

The experiment was conducted at UNESP-Jaboticabal to evaluate the quality of Brachiaria decumbens hays harvested after seed ripening. The hays were submitted to the following treatments: control, anhydrous ammonia (3.0% NH₃ in the DM), and urea (5.0% in the DM). The chemical composition, digestibility and the performance of steers were evaluated using a complete randomized block design with three treatments and six replications. The ammoniation either with NH3 or urea increased (P< 0.05) the CP content, and the IVDMD. The NH₃ treatment reduced (P < 0.05) the contents of NDF and ADF, and the urea application reduced (P < 0.05) the contents of hemicellulose and lignin. The ammoniation did not affect (P > 0.05) the neutral detergent insoluble nitrogen, and acid detergent insoluble nitrogen values. Steers receiving Brachiaria hay plus soybean meal (1.08 kg DM.day), hay …

Grazing Practices And Rangeland Conservation: Towards Output‐Based Contracts To Improve Relevance And Enhance Technical Innovation, Cyril Agreil, Jocelyn Haskell, John Haskell, Michel Meuret, Fred Provenza

IGC Proceedings (1997-2023)

No abstract provided.

A Comparative Test Of Melilotoides Ruthenica Experimental Varieties, Zhaolan Wang, Jiancai Du, Lili Zhao, Huifang Hu, Wanguang Shi, Feixue Zhu, Yanyan Zhang, Xiaotao Mao

IGC Proceedings (1997-2023)

No abstract provided.

Comparative Performance Of Friesian‐Sahiwal Crossbreds And Sahiwal Steers On Naivasha Stargrass In Kenya, W. B. Muhuyi, T. Muasya, S. N. Ole Sinkeet

IGC Proceedings (1997-2023)

No abstract provided.

Enhanced Performance Of Dye Sensitized Solar Cells Utilizing Platinum Electrodeposit Counter Electrodes, Attila J. Mozer, George Tsekouras, Gordon G. Wallace

Gordon Wallace

Enhanced performance was observed for dye-sensitized solar cells (DSSCs) utilizing counter electrodes based on Pt electrodeposits compared to counter electrodes based on sputtered Pt. Scanning electron microscopy of Pt electrodeposits revealed that the use of an initial cathodic overpotential pulse followed by steady electrodeposition at a mild cathodic potential yielded ∼40nm particles, compared to ∼600nm particles when no such pulse was used. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) of electrode materials suggested that Pt electrodeposits would give enhanced performance as DSSC counter electrodes compared to sputtered Pt, and this was confirmed by device testing. EIS characterization of DSSCs under …

Broad Vision: The Art & Science Of Looking, Heather Barnett, John R. A. Smith

The STEAM Journal

Undergraduate students and academic staff from diverse disciplines in the arts and sciences investigated questions of mediated vision through a year-long interdisciplinary research project at the University of Westminster, London, United Kingdom. The Broad Vision project explored the perception and interpretation of microscopic worlds, and investigated the benefits and challenges of working across disciplinary divides in a university setting. This article describes the three-phase model for interdisciplinary learning and research developed through the project, providing a valuable case study for inquiry based art/science education.

Agenda: A Low-Carbon Energy Blueprint For The American West, University Of Colorado Boulder. Natural Resources Law Center, University Of Colorado Boulder. Renewable And Sustainable Energy Institute, Western Resource Advocates, Rocky Mountain Research Station (Fort Collins, Colo.)

A Low-Carbon Energy Blueprint for the American West (Martz Summer Conference, June 6-8)

The future of the planet may depend upon our ability to increase energy supplies even as we reduce carbon emissions. This conference will address how a low-carbon energy program might evolve with a particular focus on the American West. It will focus on the future of energy in the West--on a “managed transition” to a different energy mix, on the need to nest this effort in a framework that acknowledges interconnections, and on identifying the most salient opportunities to consider the legal, political, financial, and technical challenges.

A Method To Measure The Detective Quantum Efficiency Of Radiographic Systems In Clinical Setting, Michael C. Mcdonald

Electronic Thesis and Dissertation Repository

The risks associated with exposure to radiation make it critical that digital imaging systems give the best possible images for a given dose to the patient. The DQE is the most widely accepted measure of performance and dose efficiency for digital radiography systems, however it is not commonly measured in a clinical environment as part of routine quality assurance. The primary reason for this is that the data provided to the user by clinical systems has typically undergone image processing and therefore may have a non-linear characteristic response. This is a problem because the Fourier metrics of the DQE require …

Methane Retrievals From Greenhouse Gases Observing Satellite (Gosat) Shortwave Infrared Measurements: Performance Comparison Of Proxy And Physics Retrieval Algorithms, D Schepers, S Guerlet, A Butz, J Landgraf, C Frankenberg, O Hasekamp, J-F Blavier, N M. Deutscher, D W. T Griffith, F Hase, E Kyro, I Morino, V Sherlock, R Sussmann, I Aben

Faculty of Science - Papers (Archive)

We compare two conceptually different methods for determining methane column-averaged mixing ratios (X_CH4) from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared (SWIR) measurements. These methods account differently for light scattering by aerosol and cirrus. The proxy method retrieves a CO₂ column which, in conjunction with prior knowledge on CO₂ acts as a proxy for scattering effects. The physics-based method accounts for scattering by retrieving three effective parameters of a scattering layer. Both retrievals are validated on a 19-month data set using ground-based X_CH4 measurements at 12 stations of the Total Carbon Column Observing Network (TCCON), …

A Novel Bath Lily-Like Graphene Sheet-Wrapped Nano-Si Composite As A High Performance Anode Material For Li-Ion Batteries, Jun Chen, Jun Yang, Zi-Feng Ma, Pengfei Gao, Yu-Shi He, Xiao Zhen Liao, Xiaowei Yang

Faculty of Science - Papers (Archive)

"A novel bath lily-like graphene sheet-wrapped nano-Si composite synthesized via a simple spray drying process exhibits a high reversible capacity of 1525 mAh g(-1) and superior cycling stability, which could be attributed to a synergistic effect between highly conductive graphene sheets and active nanoparticles in the open nano/micro-structure."

Citrate Synthase Activity Does Not Account For Age-Related Differences In Maximum Aerobic Performance In House Sparrows (Passer Domesticus), William A. Buttemer, C Bech, Mark A. Chappell

Faculty of Science - Papers (Archive)

We measured basal (BMR) and peak metabolic rates (PMR) in juvenile and adult House Sparrows. Juvenile birds had significantly higher BMR, but lower PMR than adult birds, despite having statistically indistinguishable body masses. We then evaluated the relation between PMR and masses of central and peripheral organs and found that pectoral muscle mass best correlated with PMR in both groups, accounting for about 35% of the variation in PMR. Because citrate synthase (CS) has such major importance in affecting the first committed step in the tricarboxylic acid cycle, we characterized CS activity levels In extracted muscles to see if this …

Improved Performance Of Porphyrin-Based Dye Sensitised Solar Cells By Phosphinic Acid Surface Treatment, K Sunahara, Alessandra Allegrucci, S Mori, Naomi A. Lewcenko, Leone Spiccia, Attila J. Mozer, Lynn Dennany, Pawel W. Wagner, David L. Officer

Faculty of Science - Papers (Archive)

Chemical surface treatment of porphyrin-sensitised titania films using bis-(4-methoxyphenyl)phosphinic acid after dye adsorption, results in large improvements in DSSC efficiencies which originate primarily from higher short circuit currents. The result was attributed to a positive shift in the TiO2 quasi-Fermi level with simultaneous retardation of charge recombination. High device performances have been achieved even using simplified electrolyte matrices devoid of the common additives, LiI and t-butylpyridine.

Enhanced Performance Of Dye Sensitized Solar Cells Utilizing Platinum Electrodeposit Counter Electrodes, Attila J. Mozer, George Tsekouras, Gordon G. Wallace

Faculty of Science - Papers (Archive)

Enhanced performance was observed for dye-sensitized solar cells (DSSCs) utilizing counter electrodes based on Pt electrodeposits compared to counter electrodes based on sputtered Pt. Scanning electron microscopy of Pt electrodeposits revealed that the use of an initial cathodic overpotential pulse followed by steady electrodeposition at a mild cathodic potential yielded ∼40nm particles, compared to ∼600nm particles when no such pulse was used. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) of electrode materials suggested that Pt electrodeposits would give enhanced performance as DSSC counter electrodes compared to sputtered Pt, and this was confirmed by device testing. EIS characterization of DSSCs under …

Testosterone Effects On Avian Basal Metabolic Rate And Aerobic Performance: Facts And Artefacts, W A. Buttemer, S Warne, C Bech, Lee Astheimer

Faculty of Science - Papers (Archive)

We examined the effects of cage size and testosterone (T) levels on basal and peak metabolic rates (BMR and PMR, respectively) and on pectoral and leg muscle masses of male house sparrows (Passer domesticus). Birds were housed either in small birdcages or in flight aviaries for at least 2 weeks prior to the initial metabolic evaluations. They were then implanted with either empty or T-filled silastic capsules and remeasured 5-6 weeks later. Birds treated with single T implants achieved breeding levels (4-6 ng/mL) and one group given double implants reached 10 ng/mL. There was no effect of T on BMR …

Brine Shrimp Ecology In The Great Salt Lake, Utah, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Hypersaline lakes are noted for their simple communities which facilitate understanding ecological interactions (Williams et al. 1990; Wurtsbaugh 1992; Jellison and Melack 1988). Nevertheless, we still cannot easily predict how environmental changes will effect the population dynamics in these lakes, at least in part because even these simple ecosystems may be more complex than we .realize. Many hypersaline lakes are dominated by the brine shrimp Artemia spp. The production of brine shrimp is often very high because the terminal, saline lakes accumulate nutrients that make them rich, and because the short food chains in them (nutrients-->phytoplankton-->brine shrimp) minim …

Sheep And Wool Industries Need To Improve Their Performance, Rob Kelly, Tim Marshall

Journal of the Department of Agriculture, Western Australia, Series 4

Today in Western Australia, sheep are run at slightly higher stocking rates, are achieving greater lambing percentages (up JO per cent) and higher wool cuts per animal ( up 0. 6 kg greasy) than in the 1960s. When all components of production are considered, the productivity of sheep fanns has increased by 2. 7 per cent per year over the past 35 years.

The challenge of the next decade is to achieve substantially greater rates of improvement than for past years if the sheep and wool industries are to maintain their significant place in Western Australian agriculture.

Producing 20-Month Old Beef Steers Off Annual Pasture, K D. Greathead, D. J. Barker, W. J. Ryan

Journal of the Department of Agriculture, Western Australia, Series 4

A recent Mt Barker experiment compared two systems of fodder conservation with continuous grazing, using two types of steers, at three stocking rates. Year-round performance, carcass composition, and resulting costs and returns per hectare were assessed.

Production per hectare was greatest from crossbred steers at the intermediate stocking rate with either type of fodder conservation.