Sponge alleleochemical induces ascidian settlement but inhibits metamorphosis

Secondary metabolites synthesised by sessile invertebrates appear to play a role in creating and maintaining space on hard substrata by repelling competitors. In this study, we investigated the responses of the larvae of the ascidian Herdmania curvata to haliclonacyclamine A (HA), the major component of a suite of cytotoxic alkaloids extracted from the sponge Haliclona sp. 628. Both Haliclona sp. 628 and Herdmania curvata inhabit the crest and slope of Heron Island Reef. High rates of settlement were induced in competent H. curvata larvae by a range of concentrations of HA, all lower than that naturally occurring in the sponge. HA did not induce precompetent larvae to settle. Although early metamorphosis of HA-induced larvae was normal, larvae exposed to all but the lowest concentration of HA were developmentally arrested after completion of tail resorption, at about 4 h after the initiation of metamorphosis. These postlarvae underwent extensive cellular necrosis within 24 h. We also demonstrate that the addition of a transcriptional inhibitor, actinomycin D, to larvae also causes inhibition of metamorphosis after tail resorption is completed. Analyses of incorporation of radiolabelled nucleotides to measure levels of transcription during normal development and after the addition of the transcriptional inhibitor indicate that there is a significant burst of transcriptional activity just after tail resorption is completed. Despite inhibiting metamorphosis at the same stage as actinomycin D, HA increases initial rates of RNA synthesis after induction of metamorphosis in a manner similar to that observed in normal postlarvae until the onset of cellular necrosis. We conclude that HA initially induces H. curvata larvae to settle and progress through early metamorphosis possibly by engaging the same pathway as other artificial and environmental cues but subsequently inhibits completion of metamorphosis, resulting in death of the postlarvae. Since HA does not affect overall transcription rates, it appears to disrupt another important developmental process during early metamorphosis.

Inscribing the organization:representations in dispute between accounting and production

This paper assumes that a primary function of management accounting is the representation of "accounting facts" for purposes such as organizational control. Accountants are able to offer conventional techniques of control, such as standard costing, as a consequence of their ability to deploy accounting representations within managerial and economic models of organizational processes. Accounting competes, at times, with other 'professional' groups, such as production planning or quality management people, in this role of representing the organization to management. The paper develops its arguments around a case illustration of cost accounting set in a low technology manufacturing environment. The research relates to a case organization in which accountants are attempting to establish the reliability of accounting inscriptions of a simple manufacturing process. The case research focuses on the documents, the inscriptions that vie for managements' attention. It is these sometimes messy and inaccurate representations which enable control of complex and heterogeneous activities at a distance. At the end of our site visits we observe quality management systems in the ascendancy over the accountants' standard costing systems. © 2006 Elsevier Ltd. All rights reserved.

Settlement of fill with particular reference to opencast coal mining sites

A study of information available on the settlement characteristics of backfill in restored opencast coal mining sites and other similar earthworks projects has been undertaken. In addition, the methods of opencast mining, compaction controls, monitoring and test methods have been reviewed. To consider and develop the methods of predicting the settlement of fill, three sites in the West Midlands have been examined; at each, the backfill had been placed in a controlled manner. In addition, use has been made of a finite element computer program to compare a simple two-dimensional linear elastic analysis with field observations of surface settlements in the vicinity of buried highwalls. On controlled backfill sites, settlement predictions have been accurately made, based on a linear relationship between settlement (expressed as a percentage of fill height) against logarithm of time. This `creep' settlement was found to be effectively complete within 18 months of restoration. A decrease of this percentage settlement was observed with increasing fill thickness; this is believed to be related to the speed with which the backfill is placed. A rising water table within the backfill is indicated to cause additional gradual settlement. A prediction method, based on settlement monitoring, has been developed and used to determine the pattern of settlement across highwalls and buried highwalls. The zone of appreciable differential settlement was found to be mainly limited to the highwall area, the magnitude was dictated by the highwall inclination. With a backfill cover of about 15 metres over a buried highwall the magnitude of differential settlement was negligible. Use has been made of the proposed settlement prediction method and monitoring to control the re-development of restored opencase sites. The specifications, tests and monitoring techniques developed in recent years have been used to aid this. Such techniques have been valuable in restoring land previously derelict due to past underground mining.

Settlement policies for small and medium-sized towns in an African context

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The Re-Emergence of Suriname’s Désiré (Desi) Bouterse: Political Acumen and Geopolitical Anxiety

This study examines some concerns that derive from Suriname‘s May-July 2010 elections, which resulted in the re-emergence of erstwhile military ruler and convicted drug trafficker, Désiré (Desi) Bouterse, as President of the Republic. The victory reflects Bouterse‘s political acumen in aggregating disparate political interests and in establishing a viable coalition government. But because of his history and profile, this triumph has generated anxiety in some places internationally. In this respect, the study examines anxieties related to three matters: (a) relations with Guyana, where there is an existing territorial dispute and a recently resolved maritime dispute, (b) illegal drug trafficking operations, and (c) foreign policy engagement with Venezuela. There has been a flurry of bilateral activities—including several presidential summits—with Guyana since President Bouterse‘s inauguration, albeit seemingly more about symbolism than substance. Although the maritime dispute was settled by a Tribunal of the United Nations Convention of the Law of the Sea in 2007, the 15,000 km2 New River Triangle is still unresolved. Indeed, in June 2011 President Bouterse reasserted Suriname‘s claim to the Triangle. Suriname has upped the ante in that dispute by portraying internationally the map of Suriname as inclusive of the disputed area. In all likelihood that self-redefinition slowly will become the country‘s cartographic definition in the eyes of the world if Guyana does not successfully rebuff that move or pursue the definitive settlement of the dispute. A geonarcotics assessment shows Suriname to be still heavily implicated in trafficking, because of geography, law enforcement limitations, corruption, and other factors. But despite Bouterse‘s drug-related history and that of former senior military officers, several reasons suggest the inexpediency of a narco-state being created by Bouterse. As well, as part of Suriname‘s pursuit of increased Caribbean and South American engagement, it has boosted relations with Venezuela, which has included it in PetroCaribe and provided housing and agricultural aid. However, the engagement appears to be driven more by pragmatism and less by any ideological affinity with Hugo Chavez.