1,873,112 research outputs found
Giant Magnons and Giant Gravitons
Get PDFIn this thesis we shall present work concerning the description of the emergence of solitonic fundamental strings from stable, finite energy, compact D3-branes in a subspace of and their subsequent interaction. We work in the planar limit and focus on states of large angular momentum corresponding to large R-charge in the dual gauge theory.
We begin by constructing the full set of boundary giant magnons on attached to the maximal giant graviton by mapping from the general solution to static sine-Gordon theory on the interval. We then compute the values of the anomalous dimension, , of the dual gauge theory operators at finite , examining the behaviour of the leading order corrections when is large.
We then consider the Born-Infeld theory of the giant graviton itself coupled to the background 5-form flux. Constructing BIon spike solutions that correspond to the world volume description of the boundary giant magnons we find a limit amenable to analysis which returns the full range of behaviour exhibited at finite .
Finally we produce the open strings on that correspond to the solutions of integrable boundary sine-Gordon theory. Relating the boundary parameters in a way that ensures a given set of string boundary conditions we describe the scattering of giant magnons with non-maximal giant gravitons and calculate the leading contribution to the associated magnon scattering phase. Our method necessarily describes all integrable scatterings of giant magnons with giant gravitons
Observing giant panda habitat and forage abundance from space
No full textGiant pandas are obligate bamboo grazers. The bamboos favoured by giant pandas are typical forest understorey plants. Therefore, the availability and abundance of understorey bamboo is a key factor in determining the quantity and quality of giant panda food resources. However, there is little or no information about the spatial distribution or abundance of bamboo underneath the forest canopy, due to the limitations of traditional ground survey and remote sensing classification techniques. In this regard, the development of methods that can predict the understorey bamboo spatial distribution and cover abundance is critical for an improved understanding of the habitat, foraging behaviour and distribution of giant pandas, as well as facilitating an optimal conservation strategy for this endangered species. The objectives of this study were to develop innovative methods in remote sensing and GIS for estimating the giant panda habitat and forage abundance, and to explain the altitudinal migration and the spatial distribution of giant pandas in the fragmented forest landscape. It was concluded that 1) the vegetation indices derived from winter (leaf-off) satellite images can be successfully used to predict the distribution of evergreen understorey bamboo in a deciduous-dominated forest, 2) winter is the optimal season for quantifying the coverage of evergreen understorey bamboo in a mixed temperate forest, regardless of the classification methods used, 3) a higher mapping accuracy for understorey bamboo in a coniferous-dominated forest can be achieved by using an integrated neural network and expert system algorithm, 4) the altitudinal migration patterns of sympatric giant pandas and golden takins are related to satellite-derived plant phenology (a surrogate of food quality) and bamboo abundance (a surrogate of food quantity), 5) the driving force behind the seasonal vertical migration of giant pandas is the occurrence of bamboo shoots and the temperature variation along an altitudinal gradient, 6) the satellite-derived forest patches occupied by giant pandas were significantly larger and more contiguous than patches where giant pandas were not recorded, indicating that giant pandas appear sensitive to patch size and isolation effects associated with forest fragmentation. Overall, the study has been shown the potential of satellite remote sensing to map giant panda habitat and forage (i.e., understorey bamboo) abundance. The results are important for understanding the foraging behaviour and the spatial distribution of giant pandas, as well as the evaluation and modelling of giant panda habitat in order to guide decision-making on giant panda conservation. <br/
Improving Survivorship of Giant Clams Larvae
Get PDFOne of the problems faced in giant clams culture is high mortality rate during larvae stages.
These series of research attempt to improve survivorship of giant clams larvae by several
different treatments, such as applying antibiotics, nutrient addition, feeding with different
microalgae, and introduction of zooxanthellae at different time. The results show that
survivorship was significantly improved by applying Streptomycin (10 ppm) before
fertilization and when it is combined with Chloramphenicol (5 ppm). Ammonium addition
was also increased survivorship of giant clams larvae. On the other hand, feeding with
different microalgae was not significantly improved the larvae survivorship. Introducing
zooxanthellae at early stage before metamorphosis (day 3 – 4) was also improving
survivorship of the larvae
Do Giant Oilfield Discoveries Fuel Internal Armed Conflicts?
Get PDFWe use new data to examine the effects of giant oilfield discoveries around the world since 1946. On average, these discoveries increase per capita oil production and oil exports by up to 50 percent. But these giant oilfield discoveries also have a dark side: they increase the incidence of internal armed conflict by about 5-8 percentage points. This increased incidence of conflict due to giant oilfield discoveries is especially high for countries that had already experienced armed conflicts or coups in the decade prior to discovery.Natural resources, resource curse, petroleum, armed conflict, civil war
OPTIMAL MANAGEMENT OF GIANT-CLAM FARMING IN SOLOMON ISLANDS
Get PDFGiant-clam farming is undertaken by coastal villagers in Solomon Islands as part of a research and development project of the International Center for Living Aquatic Resources Management (ICLARM). The production technology is simple and does not require a large capital investment. The main inputs are clam seed, labour and time. Labour is used for activities such as seeding, cleaning, thinning and harvesting. In this paper, a bioeconomic model is used to explore optimal farm management. The theoretical basis for this analysis is found in the economic theory of optimal forestry exploitation. The management variables considered are husbandry applied to cleaning and the frequency with which thinning is undertaken. The optimal cycle-length is determined for both a single clam harvest and multiple harvests. The labour requirements of various management scenarios are identified for the multiple-cycle case.bioeconomics, giant clams, subsistence mariculture, Farm Management,
ESTIMATING CONTRIBUTION OF ZOOXANTHELLAE TO ANIMAL RESPIRATION (CZAR) AND TO ANIMAL GROWTH (CZAG) OF GIANT CLAM Tridacna maxima
Get PDFZooxanthellae are symbiotic dinoflagellate algae which live in association with marine invertebrates including giant clams. These algae are capable of translocating part of their photosynthetic products to the host. This translocation is one of the nutrition sources of the host. The present study aims to calculate the contribution of zooxanthellae on the energy requirements of adult giant clam (Tridacna maxima) during their respiration and growth processes. The result showed that zooxanthellae are capable of contributing 260.67% and 452.54% energy required by giant clams for respiration and growth during summer and 171.51% and 273.51 % during winter, respectively. It suggests that all the energy required for these two processes can be supplied by zooxanthellae
Jolly Green Giant (full front view)
No full textFull front view of Jolly Green Giant advertising icon. Plastic figure.https://scholarscompass.vcu.edu/brandcenter_icons/1182/thumbnail.jp
Jolly Green Giant (full rear view)
No full textFull back view of Jolly Green Giant advertising icon. Plastic figure.https://scholarscompass.vcu.edu/brandcenter_icons/1183/thumbnail.jp
The rural context of giant clam mariculture in Solomon Islands: an anthropological study
Get PDFHighlights the traditional importance of giant clams, and how participatory farming research can best be carried out within the islands' culture.Clam culture, Marine aquaculture, Small scale aquaculture, Rural development, Sociological aspects, Aquaculture development, Popular participation, Tenure, Solomon Islands, Tridacna, Hippopus
Restoring giant kokopu (Galaxias argenteus) populations in Hamilton's urban streams
No full textIn this study, options for restoring fish populations in Hamilton City (37.47'S, 175.19'E) were explored. Habitat and fish populations in Hamilton urban streams were manipulated using a two-fold experimental design. Firstly, habitat was enhanced in ten urban streams with three continuous treatments in a 60-m reach at each site (20 m with 10 ponga logs, 20 m with 20 hollow clay pipes, and 20 m with no added structure). Secondly, juvenile farm-reared giant kokopu (Galaxias argenteus), were stocked into five of the enhanced stream sections. Giant kokopu are threatened and occur naturally in Hamilton urban streams in sparse populations. The abundance of wild fish was monitored before and after enhancement and fish release from November 2006 to November 2007. Stocked fish were monitored for eight months, from April to November 2007. Over this time electric fishing was conducted three times, trap nets (Gee minnow and fyke nets) were set monthly and spotlighting was conducted monthly at three release sites where water clarity allowed.
Anticipated outcomes of this research were; to determine whether giant kokopu abundance in Hamilton urban streams is limited by recruitment or by habitat, and to assist with the development of methods to restore fish populations in Hamilton City urban streams.
Logs used as enhancement structures in Hamilton urban streams provided more stable habitat for fish and created more suitable microhabitat than pipe structures. Pipes moved considerably during high flows, and their instability made them less effective at providing habitat. Within the study sites there appeared to be complex interactions with turbidity, stream width and depth, which complicated the effect of the habitat structures. The limited replication and variability among sites contributed to statistically insignificant results using analysis of variance.
Retention and recapture rates of stocked juvenile giant kokopu were greatest at Site M11, where the stream was narrow, shallow, clear and had lower numbers and biomass of shortfin eels, compared to other survey sites. Marked and released giant kokopu were retained in the release reaches at four of the five sites, for a minimum of four months, and exhibited substantial growth. Daily growth of juvenile giant kokopu ranged from 0.19 to 0.33 mm day-1 and from 0.03 to 0.11 g day-1, exhibiting substantial growth over winter. Giant kokopu appeared to have a slight bias to the log section of enhanced habitat, but habitat selection appeared to be overwhelmingly controlled by initial habitat selection.
The stocking of farm-reared fish into urban streams was largely successful, but the success of the habitat enhancement was variable and further work is required to determine better techniques for habitat enhancement in these urban environments. It is concluded that releasing farm-reared giant kokopu can be used to restore populations especially where recruitment limitations control fish abundance and diversity
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