79 resultados para Central fiber tracker (CFT)


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The Polynesia Mana Node of the southeast and central Pacific contains 7 independent or autonomous countries or territories with only 6,000 km2 of land on 347 islands, but surrounded by 12 million km2 of EEZ. These seas contain 13,000 km2 of coral reefs as the main natural ecosystem providing food resources and opportunities for development, especially for tourism and pearl culture for 500,000 inhabitants. During the 19th and first half of the 20th centuries, there was major exploitation by the colonial powers of mother-of-pearl oysters for the button industry, as well as guano, sandalwood and trepang. The Polynesian people were largely involved in a subsistence economy and all coral reefs and lagoons were healthy. During the last two decades of the 20th, all countries experienced rapid development and urbanization, rising populations, and some increased agriculture. These developments were limited to a few islands of each country (i.e. 15 islands amongst the 347) with resulting degradation of the coral reefs around these sites. The other islands remained mostly uninhabited and pristine, and continued with a subsistence economy. Generally, there was more damage to the coral reefs through natural events such as cyclones and coral bleaching, than by human activities. There is however, an urgent need to combat the threats on some islands from increased sedimentation, over-fishing, dredging and nutrient pollution.

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The Upper Newlands Seam in the northern Bowen Basin, Queensland, Australia consists of six benches (A-F) that have different petrographic assemblages. Benches C and E contain relatively abundant inertodetrinite and mineral matter, as well as anomalously high reflectance values; these characteristics support a largely allochthonous, detrital origin for the C and E benches. Fractures and cleats in the seam show a consistent orientation of northeast- southwest for face cleats, and a wide range of orientations for fractures. Cleat systems are well developed in bright bands, with poor continuity in the dull coal. Both maceral content and cleat character are suggested to influence gas drainage in the Upper Newlands Seam. A pronounced positive correlation between vitrinite abundance and gas desorption data suggests more efficient drainage from benches with abundant vitrinite. Conversely, inertinite-rich benches are suggested to have less efficient drainage, and possibly retain gas within pore spaces, which could increase the outburst potential of the coal. (C) 2001 Elsevier Science BN. All rights reserved.

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This study examined if brain pathways in morphine-dependent rats are activated by opioid withdrawal precipitated outside the central nervous system. Withdrawal precipitated with a peripherally acting quaternary opioid antagonist (naloxone methiodide) increased Fos expression but caused a more restricted pattern of neuronal activation than systemic withdrawal (precipitated with naloxone which enters the brain). There was no effect on locus coeruleus and significantly smaller increases in Fos neurons were produced in most other areas. However in the ventrolateral medulla (A1/C1 catecholamine neurons), nucleus of the solitary tract (A2/C2 catecholamine neurons), lateral parabrachial nucleus, supramamillary nucleus, bed nucleus of the stria terminalis. accumbens core and medial prefrontal cortex no differences in the withdrawal treatments were detected. We have shown that peripheral opioid withdrawal can affect central nervous system pathways. Crown Copyright (C) 2001 Published by Elsevier Science Ltd. All rights reserved.

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Pretestis laticaecum is described from the small intestine of the freshwater turtle Emydura krefftil. The new species can be distinguished from its congener P. australianus by the following characters; significantly smaller ovary, main lymph vessels reach anterior to posterior testis, genital atrium in mid-oesophageal region, small vitelline follicles clumped around the ovary and significantly larger caeca overlapping. The, position of this species and related genera in fish, the life cycle of P. australianus and the presence of P. laticaecum in turtles suggest that it is a relatively recent host capture.

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Objective: To study the clinical, endocrine and radiological features and progress of children presenting with acquired diabetes insipidus (CDI). Methodology: Chart review of children presenting because of CDI to Brisbane paediatric endocrine clinics between 1987 and 1999. Results: Thirty-nine children (female/male ratio 21/18) aged 0.1-15.4 years (mean age 6.7 years) were identified. Aetiologies were head trauma or familial in eight cases (20.5%) each, central nervous system (CNS) tumours in five cases (12.8%), CNS malformations in four cases (10.2%), histiocytosis in three cases (7%) and hypoxia and infection in two cases (5.1%) each. Seven cases (17.9%) remain undiagnosed. Of the 32 (82%) cases with isolated anti-diuretic hormone deficiency at presentation, 24 cases (61.5%) experienced no further endocrine deficit. Additional endocrine deficits occurred mainly in the tumour or undiagnosed groups. On follow-up brain magnetic resonance imaging (MRI) scans in the seven undiagnosed cases, six patients bad mild or no change and one patient had marked improvement of MRI findings. These changes occurred 10-48 months (mean 18 months) after presentation. Conclusions: Children without an aetiological diagnosis for the uncommon condition of acquired CDI require careful follow-up. More intensive investigation at presentation (e.g. estimation of cerebrospinal fluid human chorionic gonadotrophin) promises to lessen the number of such cases. Pituitary stalk biopsies should be reserved for those patients with progressive MRI changes. If these changes do not occur early, our experience suggests that follow-up MRI scans may need to be performed only yearly.

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We report on an experimental observation of bound states of solitons in a passively mode-locked fiber soliton ring laser. The observed bound solitons are stable and have discrete, fixed soliton separations that are independent of the experimental conditions.