996 resultados para Antarctica


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The synthesis of isosorbide aliphatic polyesters is demonstrated by the use of Novozym 435, a catalyst consisting of Candida antarctica lipase B immobilized on a macroporous support Several experimental procedures were tested and azeotropic distillation was most effective in removing low mass byproduct Furthermore, the use of diethyl ester derivatives of diacid comonomers gave isosorbide copolyesters with highest Isolated yield and molecular weights The length of the diacid aliphatic chain was less restrictive, but with a clear preference for longer aliphatic chains The molecular mass values of the obtained products were equivalent or higher than those obtained by nonenzymatic polymerizations, a clear illustration of the potential of enzymatic over conventional catalysis The ability of Novozym 435 to catalyze the synthesis of isosorbide polyester with weight-average molecular weights in excess of 40000 Da was unexpected given that isosorbide has two chemically distinct secondary hydroxyl groups This is the first example in which isosorbide polyesters were synthesized by enzyme catalysis, opening a large array of possibilities for this important class of biomass-derived building blocks Because these polymers are potential biomaterials the total absence of conventional Lewis acid catalyst residues represents a major Improvement in the toxicity of the material

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The current paper presents a study conducted at The National Museum of Science and Technology in Stockholm to investigate the exhibition “Antarctica – that’s cool” from its first concept to the first workshop that is held in the exhibition. The focus is on the influence of floor staff on an exhibition and workshops as learning facilities in museums. Findings, based on visitor observation and the exhibition building process, go into the characteristics of low-budget productions and discuss the importance of staff on the exhibition floor for museums as life-long learning facilities. The holistic approach of the study provides deep insights into the complex interplay of visitors, staff and exhibitions. The results can be used for future exhibition building processes and educational programs in museums and should strengthen the museum’s position as life-long learning facility in nowadays society.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Arctic is affected by global environmental change and also by diverse interests from many economic sectors and industries. Over the last decade, various actors have attempted to explore the options for setting up integrated and comprehensive trans-boundary systems for monitoring and observing these impacts. These Arctic Observation Systems (AOS) contribute to the planning, implementation, monitoring and evaluation of environmental change and responsible social and economic development in the Arctic. The aim of this article is to identify the two-way relationship between AOS and tourism. On the one hand, tourism activities account for diverse changes across a broad spectrum of impact fields. On the other hand, due to its multiple and diverse agents and far-reaching activities, tourism is also well-positioned to collect observational data and participate as an actor in monitoring activities. To accomplish our goals, we provide an inventory of tourism-embedded issues and concerns of interest to AOS from a range of destinations in the circumpolar Arctic region, including Alaska, Arctic Canada, Iceland, Svalbard, the mainland European Arctic and Russia. The article also draws comparisons with the situation in Antarctica. On the basis of a collective analysis provided by members of the International Polar Tourism Research Network from across the polar regions, we conclude that the potential role for tourism in the development and implementation of AOS is significant and has been overlooked.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present Australian continent was a major component of the north eastern peninsula of Gondwana, itself the southern region of Pangaea, during the Permian period. Surrounding what is now Australia, were additional elements of north eastern Gondwana that are now incorporated into the tectonically complex regions of New Zealand, New Caledonia, the island of New Guinea, Timor, south east Asia, the Himalaya and southern Tibet. India was to the west and south west and Antarctica to the south. Marine water temperatures ranged from cold to temperate and tropical as Permian global climates ameliorated, global surface ocean circulation systems warmed, and due to rifting and northward drifting of some terranes.

Provincialism of global marine faunas was pronounced during the Permian and hence refined biostratigraphical correlations are often fraught with difficulty. The 'middle' Permian stratotypes approved by the International Subcommission on the Permian System have little direct relevance to correlations within the Gondwanan Region at the level of operational biostratigraphical zonal schemes. Brachiopoda are a dominant marine benthonic faunal element of Permian Gondwanan faunas and they provide refined correlations between marine basins within a specific faunal province. Modem faunal provinces are recognised by the distribution patterns of species and genera belonging to a single family or superfamily such as the Papilionoidea within the Insecta. This review provides an example from Permian Brachiopoda, using the distribution data of genera and subgenera of the superfamily Ingelarelloidea, in order to demonstrate the ability to define provinces and their 'Wallace lines' of demarcation between provinces in the geological past.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Emphanisporites rotatus McGregor emend. McGregor 1973 is a distinctive Devonian spore with a known primary source age range in Australia spanning the upper Givetian to early Frasnian (Middle to Late Devonian). This is the first record of the species from Victoria. It occurs as a reworked element in an Early Permian assemblage belonging to the Granularisporites confluens Zone derived from glacigene diamictite in the Bacchus Marsh area. As the predominant direction of Permian ice movement recorded in the Bacchus Marsh district was south-west to north-east, it is possible that the reworked spores were transported from Antarctica.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Loxocythere (Novoloxocythere) pelius subgen. et sp. nov. is described from Upper Miocene strata of the Port Phillip and Western Port Basins. Victoria. It has its acme in shallow open marine facies of latest Miocene (Cheltenhamian) age. This species, along with Loxocythere (Novoloxocythere) kerryswansoni Yassini and Jones, 1995, forms a discrete group of rotund Australian Loxocythere species that possess posterior extremities in both valves that are positioned well above mid carapace height (i.e. adjacent to dorsal margin). This feature along with a sub-triangular inner margin outline, defines a carapace shape that is distinct from that of rotund species of Loxocythere (loxocythere) Hornibrook, 1952 and Antarctiloxoconcha Hartmann, 1986. The type species of Antarctiloxoconcha – A.frigida (Neale. 1967), possesses internal carapace features that are very similar to the type species of Loxocythere - L. crassa Hornibrook, 1952. Both have relatively short carapaces and sub-quadrate inner margin outlines with posterior extremities in both valves positioned below mid carapace height. Species of Loxocythere (Novoloxocythere), in particular L. (N.) kerryswansoni, have a carapace shape that is transitional between Loxocythere and Loxoreticulatum Benson, 1964. Species of Loxoreticulatum generally possess a sub-parallelogram shaped carapace/inner margin and arched median hinge element. The latter feature is distinct from the mostly straight median hinge elements of Loxocythere (Loxocythere) and Loxocythere (Novoloxocythere) species. Species of Loxocythere (Novoloxocythere) are also readily distinguishable from relatively elongate species of Loxocythere, such as L. (L.) hornibrooki McKenzie, 1967, as the latter possess long (for genus), sub-rectangular shaped carapaces/inner margin outlines and posterior extremities below mid height.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Western Antarctic Peninsula (WAP) is a biologically rich area supporting large standing stocks of krill and top predators (including whales, seals and seabirds). Physical forcing greatly affects productivity, recruitment, survival and distribution of krill in this area. In turn, such interactions are likely to affect the distribution of baleen whales. The Southern Ocean GLOBEC research program aims to explore the relationships and interactions between the environment, krill and predators around Marguerite Bay (WAP) in autumn 2001 and 2002. Bathymetric and environmental variables including acoustic backscattering as an indicator of prey abundance were used to model whale distribution patterns. We used an iterative approach employing (1) classification and regression tree (CART) models to identify oceanographic and ecological variables contributing to variability in humpback Megaptera novaeangliae and minke Balaenoptera acutorstrata whale distribution, and (2) generalized additive models (GAMs) to elucidate functional ecological relationships between these variables and whale distribution. The CART models indicated that the cetacean distribution was tightly coupled with zooplankton acoustic volume backscatter in the upper (25 to 100 m), and middle (100 to 300 m) portions of the water column. Whale distribution was also related to distance from the ice edge and bathymetric slope. The GAMs indicated a persistent, strong, positive relationship between increasing zooplankton volume and whale relative abundance. Furthermore, there was a lower limit for averaged acoustic volume backscatter of zooplankton below which the relationship between whales and prey was not significant. The GAMs also supported an annual relationship between whale distribution, distance from the ice edge and bathymetric slope, suggesting that these are important features for aggregating prey. Our results demonstrate that during the 2 yr study, whales were consistently and predictably associated with the distribution of zooplankton. Thus, humpback and minke whales may be able to locate physical features and oceanographic processes that enhance prey aggregation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Books
Medievalism and the Gothic in Australian Culture. Edited by Stephanie Trigg.

What If? Australian History as It Might Have Been. Edited by Stuart Macintyre and Sean Scalmer.

Disputed Histories: Imagining New Zealand's Pasts. Edited by Tony Ballantyne and Brian Moloughney.

The Myth of the Great Depression. By David Potts.

Memory, Monuments and Museums: The Past in the Present. Edited by Marilyn Lake.

Connected Worlds: History in Transnational Perspective. Edited by Marilyn Lake and Ann Curthoys.

Island Ministers: Indigenous Leadership in Nineteenth Century Pacific Islands Christianity. By Raeburn Lange.

Texts and Contexts: Reflections in Pacific Islands Historiography. Edited by Doug Munro and Brij V. Lai.

Day of Reckoning. By Lachlan Strahan.

Appropriated Pasts: Indigenous Peoples and the Colonial Culture of Archaeology. By Ian J. McNiven and Lynette Russell.

Recognising Aboriginal Title: The Mabo Case and Indigenous Resistance to English-Settler Colonialism. By Peter H. Russell.

Black Glass: Western Australian Courts of Native Affairs 1936-54. By Kate Auty.

Edward Eyre, Race and Colonial Governance. By Julie Evans.

Gender and Empire. By Angela Woollacott.

Uncommon Ground: White Women in Aboriginal History. Edited by Anna Cole, Victoria Haskins and Fiona Paisley.

Mixed Relations: Asian-Aboriginal Contact in North Australia. By Regina Ganter, with contributions from Julia Martinez and Gary Lee.

Botany Bay: Where Histories Meet. By Maria Nugent.

A Man of All Tribes: The Life of Alick Jackomos. By Richard Broome and Corinne Manning.

Black Founders: The Unknown Story of Australia's First Black Settlers. By Cassandra Pybus.

Over the Mountains of the Sea: Life on the Migrant Ships 1870-1885. By David Hastings.

Ulster-New Zealand Migration and Cultural Transfers. Edited by Brad Patterson.

From Paesani to Global Italians: Veneto Migrants in Australia. By Loretta Baldassar and Ros Pesman.

Ways of Seeing China: From Yellow Peril to Shangrila. By Timothy Kendall.

East by South: China in the Australasian Imagination. Edited by Charles Ferrall, Paul Millar and Keren Smith.

Arthur Tange: Last of the Mandarins. By Peter Edwards.

Kin: A Collective Biography of a Working-Class New Zealand Family. By Melanie Nolan.

Ida Leeson A Life: Not a Blue-Stocking Lady. By Sylvia Martin.

Will Dyson: Australia's Radical Genius. By Ross McMullin.

Francis De Groot: Irish Fascist Australian Legend. By Andrew Moore.

South by Northwest: The Magnetic Crusade and the Contest for Antarctica. By Granville Allen Mawer.

From Woolloomooloo to 'Eternity': A History of Australian Baptists. 2 vols. Volume 1: Crowing and Australian Church (1831-1914), Volume 2: A National Church in a Global Community (1914-2005). By Ken R. Manley.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An important Athecate genus, Eudendrium, and a group of species of the Thecata, the latter ecologically related by life on a common substrate, are reviewed. Eudendrium, hitherto poorly known in Australia, comprises 17 species, including 10 undescribed species with 71% Australian, and high provincial endemicity. Eudendrium may be a shelf genus avoiding turbulent oceanic waters. Species of Eudendrium are predominantly epizoic and some gregariously settling colonies may live for five years. Identification of sterile material is refined by using the cnidome in a key to classification. The species and population dynamics of hydroid epiphytes of the endemic southern Australian marine angiosperm Amphibolis were investigated with revision of historically vexatious taxa. In contrast with the northern hemisphere, no Athecata are associated with southern Australian seagrasses. Seventeen species from eight thecate families are associated with the two species of Amphibolis, including one undescribed species, H&lecium amphibolum, and one new record for Australia, Aglaophenia postdentata. The Lineolariidae is revised and a new genus, Millardaria, erected for a species from seagrass in Madagascar. The high endemicity (58%) and host-specificity of hydroids to Amphibolis is an evolutionary consequence of isolation of the seagrass dating from break-up of the Tethyan Sea. Hydroids occur throughout the year in the Amphibolis leaf canopy with a mean annual epiphytism of 44% on A. antarctica in the eastern continent and 86% in the western continent; epiphytism is 52% on A. griffithii in the western continent. Half of the eight important species are dominant epiphytes across the southern continent but the species and order of abundance varies regionally. Most are pioneer colonists with short, repetetive life-cycles lasting from weeks to a few months. Three species epiphytise the seagrass stems but only one is a leaf-canopy dominant. The canopy community comprises small, fast-growing species or dwarfed variants of species larger in other habitats: these ecomorphically constant forms are associated only with seagrass. Strategies for survival in the harsh Amphibolis environment include adnate colonies and gonothecae adnate or recumbent to the substrate, marked strengthening of the hydrorhiza, various hydrodynamic adaptations of the hydrotheca, early maturation and production of numerous small ova.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Between 1884 and 1920 the Society was part of an intense period of international geographical interest, imperialism and nationalism. This empirical history shows that the Society sought to explore New Guinea, Northern and Central Australia, and Antarctica, pursuing issues of land use, labour and commercial development of these regions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis · Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An understanding of pinniped haulout behaviour can provide information on how animals interact with their environment, their foraging strategies and the behaviour of their prey. For Weddell seals Leptonychotes weddelli, knowledge of haulout patterns and the environmental drivers of haulout is comprehensive for the austral spring and summer, but is poorly described outside this period. Pinniped behaviour is commonly examined using satellite telemetry; however, it is unclear whether the behavioural state of the seal can itself influence data acquisition. We examined haulout behaviour of female Weddell seals in eastern Antarctica over 3 winters (March to August, 2006–2008) using satellite-linked data loggers. Haulout behaviour followed a diel cycle with predominantly nocturnal haulouts. The environmental variables wind speed and temperature were influential on haulout, with seals tending to haul out more in lower winds and at higher temperatures. Haulout duration decreased across the winter, as did the number of satellite uplinks, suggesting that haulout duration played a role in data acquisition. There was no evidence of a decline in tag condition over this period, indicating that the decrease in uplinks was primarily the result of the winter behaviour of the seals. Overall, the number of haulout locations in the data set was over-represented, with more uplinks per hour occurring when the seals were hauled out than when they were at sea. For Weddell seals and other ice seals, tracking data that include haulout locations can bias spatial representations of foraging behaviour (e.g. haulout sites may be mistaken for regions of area-restricted search).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Vocal recognition may function as a critical factor in maintaining the phocid mother-pup bond during lactation. For vocal recognition to function, the caller must produce individually distinct calls that are recognised by their intended recipient. Mother-pup vocal recognition has been studied extensively in colonial otariids and appears to be characteristic of this family. Although less numerous, empirical studies of phocid species have revealed a range of recognition abilities. This study investigated whether Weddell seal (Leptonychotes weddellii) females produce individually distinct 'pup contact' calls that function during natural pair reunions. Fifteen calls from each of nine females recorded in the Vestfold Hills, Antarctica were analysed. One temporal, nine fundamental frequency and five spectral characteristics were measured. Results of the cross-validated Discriminant Function Analysis revealed that mothers produce individually distinct calls with 56% of calls assigned to the correct individual. The probability of achieving this level of discrimination on novel data by chance alone is highly improbable. Analysis of eight mother-pup reunions recorded near McMurdo Sound, Antarctica further demonstrated that these 'pup contact' calls function during natural pair reunions. Behavioural analysis also revealed that pups were chiefly responsible for establishing and maintaining close contact throughout the reunion process. Our study therefore demonstrates that Weddell seal females produce calls with sufficient stereotypy to allow pups to identify them during pair reunions, providing evidence of a functioning mother-pup vocal recognition system.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study presents morphological and molecular data on hookworms from the Australian fur seal Arctocephalus pusillus doriferus (Schreber) currently identified in Australian waters as Uncinaria hamiltoni Baylis, 1933. Additional specimens from the Australian sea lion Neophoca cinerea (Péron) and the New Zealand fur seal Arctocephalus forsteri (Lesson) from Australia, and the Southern elephant seal Mirounga leonina (Linnaeus) from Antarctica, were included. Using the internal transcribed spacer (ITS), hookworms from A. p. doriferus, N. cinerea and A. forsteri were found to be genetically similar but distinct from Uncinaria spp. found in M. leonina from Antarctica, as well as from Zalophus californianus (Lesson) and Callorhinus ursinus (Linnaeus) from California. Few morphological differences were detected between these taxa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

 Lipases have applications for the industrial processing of lipids, including concentrating and/or modifying fish oil derived omega-3 fatty acids, widely used as nutritional supplement and functional food ingredients. A range of para-nitrophenol (pNP) acyl esters were synthesised as a means to rapidly screen lipases for fatty acid selectivity using spectrophotometric detection. The chosen esters were based primarily on the most abundant fatty acids present in anchovy and tuna oils. pNP derivatives of C16:1 n-7, C18:1 n-9 (OA), C18:2 n-6 (LA), C18:3 n-3 (ALA), C20:5 n-3 (EPA) and C22:6 n-3 (DHA) were synthesised. Storage stability of these pNP derivatives was shown to be at least 6 months and all pNP derivatives, including those of EPA and DHA, were shown to be stable throughout the conditions of the assay. We applied the new assay substrates for the determination of fatty acid selectivity of five widely utilised lipases. Results showed that the lipase from Candida rugosa was the most selective in terms of omega-3 specificity, preferentially hydrolysing all other medium– long chain substrates. Lipases from Rhizomucor miehei and Thermomyces lanuginosa also showed selectivity, with a significant preference for saturated fatty acids. Candida Antarctica lipase B and Aspergillus niger lipase were the least selective.