IGC Antarctic Glaciological Data Field Work 1959-60

"Submitted by RIchard P. Goldthwait to the National Science Foundation, in partial fulfillment of Grant No. NSF-G8992."At head of title: "IGC Antarctic Glaciological Data Field Work 1959-60."The interpretation of 19 snow pits dug by the 1959-60 Victoria Land Traverse gives a mean annual accumulation of 16 cm of water equivalent for the area studied. Deposition is thought to occur in the form of sastrugi instead of in blanket form and this introduces a serious error in the interpretation. Approximate mean annual air temperatures ranged between -38.4°c and -47.4°c. A map of the traverse route shows contoured elevations and sastrugi observations. The highest elevation was 2591 meters. A compilation of accumulation stakes emplaced by this traverse is made available. The Rennick Glacier which empties into Rennick Bay and extends southward for about 300 kilometers was reconnoitered by the traverse party; a sketch map is included. Accumulation stakes were measured on the Ross Ice Shelf, Skelton Glacier, and the Victoria Land Plateau near the coast of the Ross Sea. Annual values ranged from 23.5 cm to 1.7 cm of water equivalent; the higher accumulation is on the Ross Ice Shelf.National Science Foundation Grant No. NSF-G899

Bioactive factors in microbial biomass have the capacity to offset reductions in the level of protein in the diet of black tiger shrimp, Penaeus monodon

A factorial experiment was conducted with black tiger shrimp (Penaeus monodon) juveniles to determine the effects of varying protein inclusion in the diet and also varying inclusion of a microbial biomass on growth, feed and nutrient utilization when fed in indoor laboratory conditions. The growth performance of the shrimp improved with increasing diet protein level. However, in the absence of the added microbial biomass, this growth performance plateaued at the 480. g/kg protein level. The addition of the microbial biomass improved growth at each inclusion level of both protein and microbial biomass. No plateau in growth was observed with the addition of the microbial biomass. Improvements in feed conversion were seen with increasing dietary protein levels and also the inclusion of the microbial biomass. Examination of the feed intake of each treatment supports that there was a combined effect of an increase in feed intake and improvements in feed conversion that contributed to the improvements in growth performance with the use of the microbial biomass, but the increases in dietary protein level largely influenced growth through improvements in feed conversion

Photometric Variability in Earthshine Observations

The identification of an extrasolar planet as Earth-like will depend on the detection of atmospheric signatures or surface non-uniformities. In this paper we present spatially unresolved flux light curves of Earth for the purpose of studying a prototype extrasolar terrestrial planet. Our monitoring of the photometric variability of earthshine revealed changes of up to 23 % per hour in the brightness of Earth's scattered light at around 600 nm, due to the removal of specular reflection from the view of the Moon. This variability is accompanied by reddening of the spectrum, and results from a change in surface properties across the continental boundary between the Indian Ocean and Africa's east coast. Our results based on earthshine monitoring indicate that specular reflection should provide a useful tool in determining the presence of liquid water on extrasolar planets via photometric observations.Comment: To appear in Astrobiology 9(3). 17 pages, 3 figures, 1 tabl

Destruction of chemical warfare agent simulants by air and moisture stable metal NHC complexes

The cooperative effect of both NHC and metal centre has been found to destroy chemical warfare agent (CWA) simulants. Choice of both the metal and NHC is key to these transformations as simple, monodentate N-heterocyclic carbenes in combination with silver or vanadium can promote stoichiometric destruction, whilst bidentate, aryloxide-tethered NHC complexes of silver and alkali metals promote breakdown under mild heating. Iron–NHC complexes generated in situ are competent catalysts for the destruction of each of the three targetted CWA simulants

Critical variability exists in the digestible value of raw materials fed to black tiger shrimp, Penaeus monodon: The characterisation and digestibility assessment of a series of research and commercial raw materials

The digestibility of a suite of raw materials was determined when fed to black tiger shrimp (Penaeus monodon) in a series of three experiments. A total of 29 commercial and research raw materials were evaluated using the diet replacement digestibility method. Each of the reference and test diets were fed to tanks of shrimp for one-week prior to commencing faecal collection. The collected faecal samples were kept separate from any feed residue through using a discrete feeding period, after which uneaten feed was removed before a separate faecal collecting period. The same reference diet and soy protein concentrate diet were used across each of the three experiments and demonstrated consistent digestibility using this method. Most raw materials demonstrated some utility for use in diets for shrimp, with digestible protein or energy values >0.800. However, there were some raw materials (e.G. camelina meal) that provided very little nutritive value for shrimp. This study presents data on the digestibility and digestible nutrient content of a wide variety of raw materials, providing a clear basis for progressing to formulating shrimp diets on a digestible protein and energy basis, thereby optimising dietary formulation, maximising ingredient utilisation and reducing impacts of uneaten feed

Soil capability assessment for expanding irrigated agriculture in the Irwin focus area and surrounding lands

The Midlands groundwater and land assessment is a $4.7 million Water for Food project using Royalties for Regions funding. It is seeking to confirm groundwater availability in focus areas that may form precincts of 2000–3000ha suitable for intensive irrigated horticulture. Irwin is one of these. The Department of Water identified the Irwin focus area for investigation for irrigated agriculture potential. It covers almost 7000ha to the east of Dongara in the Mid West region of Western Australia. This report provides the land assessment for the Irwin area. We expanded the investigation to include land outside of the focus area because our review of the regional soil-landscape mapping indicated that this land had potential for irrigated agriculture. This ‘survey area’ covers about 34000ha. This report details the soil-landscapes in the Irwin survey area and provides related information, including descriptions of geology, geomorphology and the soils, and an outline of the capability of the soil and land for irrigated horticulture. To provide a better assessment for irrigated agriculture, we remapped the previous 1:250000 soil-landscapes of the survey area at the more-detailed scale of 1:100000. We described 117 soil sites and 15 of these received a significant amount of laboratory analyses. Our assessment found that over half of the soils in the survey area have moderate to good capability for horticulture, with the following limitations: • The available water is unsuitable for irrigation. • The fertile Yardarino Flats have moderate amounts of salt at depth in some areas. While this is not a risk for broadacre agriculture, irrigating these soils may cause the watertable to rise and bring salt closer to the rooting zone. High evaporation may also lead to salt concentrating at the soil surface. • The alluvial soils have highly sodic subsoils, indicating poor drainage and a risk of waterlogging. The boron levels of some subsoils are high enough to limit root growth of some crops. • The wind erosion risk is high for most sandy-surfaced soils, so investment in soil management would be required, especially for annual horticulture. • With the high evaporation and the need to control wind erosion, irrigation in this area has a high water-use requirement. • The use of poorer quality water for irrigation can also be problematic on the sandy slopes surrounding the clayey alluvial flats, potentially leading to a build-up of salt in the subsoil. Apart from small, niche opportunities, water of a suitable quality in the quantities required for extensive irrigated agriculture development is not generally available in the Irwin area. Dryland cropping and grazing would be the preferred land uses on the highly productive alluvial flats, and irrigation on the surrounding sandplain would require careful management

Load transfer across cracks and joints in concrete slabs on grade

This research has investigated the behaviour of joints and cracks under single and multiple cycles of load. This provides an increased understanding of concrete slab on grade performance, enabling more effective design and monitoring procedures. Examination of the geometry of cracks and joints within concrete slabs on grade has demonstrated that the commonly assumed parallel formation is erroneous. Measurements using embedded strain gauges, coring and surface profile levelling have uncovered that a high percentage of joints will contain larger crack widths at the surface than at the base, caused by differential shrinkage. The opening itself is relatively linear; however, the top 50mm of the slab is prone to a higher gradient of movement due to the increased drying effect towards the surface. A series of deflection tests using a Falling Weight Deflectometer and Prima dynamic plate enabled slab response under load to be evaluated. Four sites were examined in total and correlations found between: load transfer, load step, edge cantilever and crack geometry. This produced valuable information regarding the influence of load transfer and crack width on the overall slab behaviour. Foundation voiding and crack face free slip was also shown to influence deflection magnitude. A small-scale test facility was developed for the assessment of deterioration in various 'V' shaped and parallel crack widths under high cycle loading. The data demonstrated that joint/crack failure contains four distinct phases of deterioration, each of which is controlled by a different mechanism. 'V' shaped cracks produced a much greater load transfer than that of a parallel crack with the incorporation of A142 mesh and steel fibres reducing differential displacement. Load magnitude and aggregate size were also shown to have significant effects. The value of reinforcement was found to assist with serviceability requirements, keeping displacement within acceptable levels and preventing the onset of serious degradation A finite element model was developed to enable the load transfer mechanism results from the laboratory test to be used in the assessment of full slab response. Simulations of field testing produced a series of lower bounds in respect to deflections and the associated response calculations. Theoretical behaviour of a typical slab was assessed with subbase support, joint stiffness, slab thickness and the incorporation of a subbase, found to be highly influential in reducing slab deflections. The three main sections of work comprising site data collection, laboratory testing and Finite Element modelling have been used together to provide a much greater understanding of the influence of cracks and joints. This has included the deterioration of cracks over time and an examination of how this and other site-based factors affect overall slab behaviour.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The combined effect of feed frequency and ration size of diets with and without microbial biomass on the growth and feed conversion of juvenile Penaeus monodon

Feed management strategies that maximize shrimp growth and optimize feed utilization are critical to the cost-effectiveness of production. In this study, juvenile Penaeus monodon (~3 g) were cultured for 6 weeks in a laboratory-based clear-water tank system. The experiment design was a three-way factorial with two diets (Diet A - standard industry formulation or Diet B - the same diet with 10% microbial biomass), two feed frequencies (twice or six times daily) and three rations (60%, 80% and 100% of satiation). The results demonstrated clear growth benefits of feeding more than two times per day and feed efficiency benefits of a restricted ration. There was also a significant interaction between frequency and ration, which demonstrated that growth improved using six feeds compared with two feeds as ration amount decreased. The effects of frequency and ration were consistent for both diets; however, the addition of a microbial biomass provided significant growth improvements across all treatments. These outcomes define the gains produced by the combined effect of frequency and ration and suggest a compromise between feed utilization and feeding effort for adoption in feed management strategies