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Existing Structures (existing + structure)
Selected AbstractsThe reaction-diffusion system: a mechanism for autonomous pattern formation in the animal skinGENES TO CELLS, Issue 6 2002Shigeru Kondo How do animals acquire their various skin patterns? Although this question may seem easy, in fact it is very difficult to answer. The problem is that most animals have no related structures under the skin; therefore, the skin cells must form the patterns without the support of a prepattern. Recent progress in developmental biology has identified various molecular mechanisms that function in setting the positional information needed for the correct formation of body structure. None of these can explain how skin pattern is formed, however, because all such molecular mechanisms depend on the existing structure of the embryo. Although little is known about the underlying molecular mechanism, many theoretical studies suggest that the skin patterns of animals form through a reaction-diffusion system,a putative ,wave' of chemical reactions that can generate periodic patterns in the field. This idea had remained unaccepted for a long time, but recent findings on the skin patterns of fish have proved that such waves do exist in the animal body. In this review, we explain briefly the principles of the reaction-diffusion mechanism and summarize the recent progress made in this area. [source] COLONIALISM AND LONG-RUN GROWTH IN AUSTRALIA: AN EXAMINATION OF INSTITUTIONAL CHANGE IN VICTORIA'S WATER SECTOR DURING THE NINETEENTH CENTURYAUSTRALIAN ECONOMIC HISTORY REVIEW, Issue 3 2008Edwyna Harris colonialism; democracy; economic growth; institutional efficiency; water rights Institutional change in water rights in the nineteenth century Australian colony of Victoria raised institutional efficiency, which contributed to long-run economic growth. High-quality human capital and the extension of voting rights (franchise) were crucial for efficient institutional change in the water sector. Quality human capital (literacy) appeared to increase the rural population's awareness of the economic impact of the existing structure of water rights that may have constrained growth in the agricultural sector and reduced investment incentives. Extension of the franchise allowed the rural population to exert political pressure for enactment of change in water rights, which resulted in efficiency-enhancing policies and efficient institutions. The findings show these two factors were more important than Victoria's British colonial heritage in determining whether growth-enhancing institutional change took place. [source] Negotiating Islam: Conservatism, Splintered Authority and Empowerment in Urban BangladeshIDS BULLETIN, Issue 2 2010Samia Huq Bangladesh has recently been seeing a rise in religiosity which has been treated as problematic, anti-secular and anti-progressive within the public sphere. Various writers describe this trend as having a disempowering effect on women and negating their self-expression. However, underlying these views is the assumption that the assertion of women's agency is not enough if it does not confront existing structures of relations. This article asks whether it is possible that in seeking changes in certain aspects of one's life, existing gender relations are not necessarily transformed, but indirectly challenged and reconfigured? The conclusion suggests that rather than a polarisation of the secular and religious ways of living most people are in fact in between, negotiating between the two camps, and borrowing ideas and ways from both. [source] Gene Transfer in Human Vestibular Epithelia and the Prospects for Inner Ear Gene Therapy,,THE LARYNGOSCOPE, Issue 5 2008Bradley W. Kesser MD Abstract Transfer of exogenous genetic material into the mammalian inner ear using viral vectors has been characterized over the last decade. A number of different viral vectors have been shown to transfect the varying cell types of the nonprimate mammalian inner ear. Several routes of delivery have been identified for introduction of vectors into the inner ear while minimizing injury to existing structures and at the same time ensuring widespread distribution of the agent throughout the cochlea and the rest of the inner ear. These studies raise the possibility that gene transfer may be developed as a potential strategy for treating inner ear dysfunction in humans. Furthermore, a recent report showing successful transfection of excised human vestibular epithelia offers proof of principle that viralgene transfer is a viable strategy for introduction andexpression of exogenous genetic material to restore function to the inner ear. Human vestibular epithelia were harvested from patients undergoing labyrinthectomy, either for intractable Ménière's disease or vestibular schwannoma resection, and cultured for as long as 5 days. In those experiments, recombinant, multiply-deleted, replication-deficient adenoviral vectors were used to transfect and express a reporter gene as well as the functionally relevant gene, wild-type KCNQ4, a potassium channel gene that when mutated causes the autosomal dominant HL DFNA2. Here, we review the current state of viral-mediated gene transfer in the inner ear and discuss different viral vectors, routes of delivery, and potential applications of gene therapy. Emphasis is placed on experiments demonstrating viral transfection of human inner ear tissue and implications of these findings and for the future of gene therapy in the human inner ear. [source] Francis-Jones Morehen Thorp (FJMT)ARCHITECTURAL DESIGN, Issue 2 2010Fleur Watson Abstract The output of FJMT varies greatly in scale and location. The practice has completed community schemes in Sydney's suburbs as well as accommodation for prestigious institutions in the city centre. It has adapted existing structures on heritage sites as well as producing high-tech newbuilds. As Fleur Watson and Martyn Hook explain, what FJMT's projects have in common is an unwavering commitment to the enhancement of the public realm. The firm embraces the full responsibility of building in the sensitive urban and topographic context of this harbour city with its ridges and coastal inlets. Copyright © 2010 John Wiley & Sons, Ltd. [source] Querkrafttragfähigkeit von Fahrbahnplatten ohne QuerkraftbewehrungBETON- UND STAHLBETONBAU, Issue 10 2009Günter Rombach Prof. Dr.-Ing. Versuche; Berechnungs- und Bemessungsverfahren Abstract Es wird über Versuche zur Querkrafttragfähigkeit von Brückenfahrbahnplatten aus Stahlbeton berichtet. Diese zeigen, dass die bekannten Rechenansätze für Bauteile ohne Querkraftbewehrung nach DIN 1045-1 bzw. DIN-FB 102 für Fahrbahnplatten auf der sicheren Seite liegen, die tatsächliche Tragfähigkeit aber weit unterschätzt wird. Weitere Ansätze zur Berechnung der Querkrafttragfähigkeit von Stahlbetonbauteilen ohne Querkraftbewehrung werden erörtert. Während die Modelle bei der Auswertung einer Datenbank von Balkenversuchen eine gute Übereinstimmung aufweisen, zeigt der Vergleich mit den Modellversuchen, dass die meisten Rechenverfahren die Tragfähigkeit der Platten unterschätzen. Zur Berechnung der Querkrafttragfähigkeit von Platten ohne Querkraftbewehrung unter Punktlasten wird ein Modell vorgeschlagen, welches die Querkrafttragfähigkeit mit der Zugbeanspruchung der Biegezugzone im kritischen Bereich verknüpft. Shear Resistance of Bridge Decks without Transverse Reinforcement The design of concrete bridge deck slabs is of major concern since the introduction of the Eurocodes as the calculated shear capacity of slabs without stirrups and staggered reinforcement according to the new design standards is often considerably smaller compared to the former regulations i.e. DIN 1045:88. This raises the question whether the existing structures are still save. A series of 12 tests on 4 different specimens representing a bridge deck was performed to examine the real load bearing behaviour of a slab with and without shear reinforcement under a wheel (point) load. The evaluation of the test results revealed, that the current design formula with an assumed elastic shear force distribution leads to rather conservative values of shear capacity for bridge deck slabs. Various approaches for shear design are discussed and the accuracy is checked by means of a shear database and the test results. A new model to calculate the shear capacity is proposed which shows a better agreement with test data than the known approaches. [source] | |||||||||||||