98 resultados para Connotative significance


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Ostracoda able to tolerate significant fluctuations in salinity occur as fossils in latest Late Miocene and earliest Late Pliocene strata of the Nepean 1 borehole within the Port Phillip Basin. The main euryhaline species present are Osticythere baragwanathi (Chapman & Crespin), Leptocythere hartmanni (McKenzie), Xestoleberis cedunaensis Hartmann and Tanella gracilis Kingma. Euryhaline ostracods occur in both high diversity, high abundance fossil ostracod assemblages and in low diversity, high abundance  assemblages. These latest Late Miocene and earliest Late Pliocene fossil ostracod assemblages accumulated close to the maximum point of flooding during respective marine transgressions onto the northern Bass Strait hinterland. The presence of euryhaline Ostracoda in these assemblages  is reminiscent of ostracod occurrences associated with modern day SE Australian barrier coastlines. Euryhaline ostracods are not common in earlier Cenozoic sediments of SE Australia and Osticythere baragwanathi makes its first appearance in the latest Late Miocene beds of the Nepean 1 borehole. This latter occurrence is interpreted to reflect the initial phase of development for the modern SE Australian barrier coastline and in particular, the initial formation of Port Phillip Bay as a coastal geomorphological feature.

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The molecular mechanisms underlying thiol-based redox control are poorly defined. Disulfide bonds between Cys residues are commonly thought to confer extra rigidity and stability to their resident protein, forming a type of proteinaceous spot weld. Redox biologists have been redefining the role of disulfides over the last 30–40 years. Disulfides are now known to form in the cytosol under conditions of oxidative stress. Isomerization of extracellular disulfides is also emerging as an important regulator of protein function. The current paradigm is that the disulfide proteome consists of two subproteomes: a structural group and a redox-sensitive group. The redoxsensitive group is less stable and often associated with regions of stress in protein structures. Some characterized redox-active disulfides are the helical CXXC motif, often associated with thioredoxin-fold proteins; and forbidden disulfides, a group of metastable disulfides that disobey elucidated rules of protein stereochemistry. Here we discuss the role of redox-active disulfides as switches in proteins.

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Due to the lack of fossil evidence, the age of Amugang Group, previously referring to the large area of metamorphic formations developed along the south of Longmucuo-Shuanghu suture in southern Qiangtang area, northern Tibet, has been under heated debate. Some geologists were convinced that the age of metamorphic formations was of Pre-Devonian according to the emergence of nonmetamorphic fossil-beating Devonian in Chasang area, north of the suture. Most geologists believed that its age was of Pre-Sinian. From 2003 to 2004, we collected a large amount of Nautiloid and Graptolite fossils in upper metamorphic formations of Mayigangri area and determined the age to be middle and Late Ordovician-Silurian. It is the first time to discover the Early Paleozoic strata based on reliable fossils, which not only provides evidence to its age ascription, classification of the strata and its correlation to adjacent areas but also offers data to lithofacies, palaeogeography and tectonic pattern of studied area.

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There is no any sediments contain fossils which formed earlier than Middle Ordovician in northern Tibet yet. It is very important whether have developed the Cambrian to Early Ordovician sedimentary strata. During geological mapping of Xainza County in 2000, Tetragraptus approximatus, the typical one of graptolite belts which cosmepolitically distributed in the Arenigian of Early Ordovician, was collected from the so-call Pre-Sinian Nianqingtanggula Group. So there is developped the Early Ordovician sediments and we have established Zakang Formation and Taduo Formation which perfected the Plaeozoic sequences in northern Tibet. According to these, we can realize tectonic control, palaeogeographrc pattern as well as palaeobiogeographic distribution of the Qinghai-Tibet Plateau in the early Paleozoic and also provided the materials to the cosmepolitical biostratigraphic contrast.

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During the regional geological mapping of the 1∶250000 Mayigangri Sheet, a very complete ophiolite was discovered in the Jiaomuri area, which consists of radiolarian chert, pillow basalt, gabbro, diabase and metaperidotite. This ophiolite is the most intact and complete one in the central Qiangtang area.

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Background: Birch-pollen allergens are an important cause of early spring hay fever and allergic asthma. Recently, we reported a mechanism for the release of respirable allergenic particles from birch pollen containing the major allergen Bet v 1. In this study, we aimed to assess the immunologic significance of the released Bet v 1-containing starch granules in the environment.

Methods: A two-site monoclonal antibody-based assay (ELISA) was employed to quantitate Bet v 1 in high-volume air sampler filter extracts, and immunogold-labelling was used on sections of these extracts to localize Bet v 1. Immunoblot analyses were performed with pooled sera from patients sensitive to birch pollen.

Results: Atmospheric starch granules contained Bet v 1, and the concentration increased upon light rainfall. Sera from patients allergic to birch allergens recognized extracts from isolated starch granules.

Conclusions: The clinical implications of these findings are that starch granules released from birch pollen are potentially able to trigger allergic asthmatic reactions to Bet v 1, since the allergen occurs in respirable particles. Thus, clinicians can advise asthma patients to remain indoors on days of light rainfall during the birch-pollen season to avoid high levels of allergen exposure.

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Childlessness is an increasing trend, internationally and in Australia. The few studies exploring the lived experiences of childless women have been conducted in America, Canada and the United Kingdom; predominantly during the 1980s and 1990s. The experiences of childless women in contemporary Australia remain under-researched. This hermeneutic phenomenological study sought to enhance understanding of the lived experience of being a childless woman in contemporary Australia. In-depth interviews with five childless women revealed five key themes as significant facets of the experiences of childless women: notions of ‘natural’ and ‘unnatural’; woman = mother; childlessness as a discrediting attribute; feeling undervalued; and the significance of being childless. By privileging the experiences of childless women in a pronatalist society, it is apparent that misconceptions and stereotypes about childlessness continue to pervade. This study contributes to understanding this growing population group; highlighting that while childlessness is increasingly acknowledged, it is still not completely understood.