2,587 research outputs found
Urban Principles for Ecological Landscape Design and Maintenance: Scientific Fundamentals
Urban ecology is a rapidly developing scientific discipline with great relevance to sustainable city design and management. Though several frameworks have been proposed in the last 10 years, urban ecology, as yet, has no complete, mature theory. There are, however, general principles emerging that may facilitate the development of such a theory. In the meantime, these principles can serve as useful guides for ecological landscape design and maintenance. This paper aims to use the principles to conceptually frame a series of papers to follow in this special issue. The main ecological principles concerning cities are that: 1) Cities are ecosystems; 2) Cities are spatially heterogeneous; 3) Cities are dynamic; 4) Human and natural processes interact in cities; and 5) Ecological processes are still at work and are important in cities. The first three principles address the structure of cities and the change in structure through time. The remaining two principles focus on ecological processes in cities. We briefly summarize each of these principles and their roots in the ecological and design fields. Each principle points to ecological functions that can be translated into ecosystem services. Application of these principles to ecological landscape design and maintenance is discussed
Granulocyte-macrophage colony stimulating factor (GM-CSF) after high-dose melphalan in patients with advanced colon cancer.
Nine patients with progressive, metastatic disease from primary carcinoma of the colon were entered into a phase I/II study using continuous intravenous infusions of granulocyte-macrophage colony-stimulating factor (GM-CSF) and high dose melphalan (120 mg m-2). GM-CSF was given alone to six patients during the first part of the study to determine a dose that would produce a peripheral leucocyte count (WCC) greater than or equal to 50 X 10(9) 1(-1) and was initially given at 3 micrograms kg-1 day-1 and escalated to 10 micrograms kg-1 day-1 after 10 days. The infusion was discontinued when the WCC exceeded 50 X 10(9) 1(-1) and after a gap of one week, melphalan was given over 30 min. GM-CSF was recommenced 8 h later and was continued until the neutrophil count had exceeded 0.5 X 10(9) 1(-1) for greater than 1 week. One patient achieved a WCC greater than 50 X 10(9) 1(-1) with GM-CSF 3 micrograms kg-1 day-1, but the other five who entered this phase of the study required dose escalation to 10 micrograms kg-1. No toxicity attributed to GM-CSF was seen. After melphalan, the median times to severe neutropenia (less than 0.5 X 10(9) 1(-1] and thrombocytopenia (greater than 20 X 10(9) 1(-1] were 6 and 9 days respectively. The median durations of neutropenia and thrombocytopenia were 14 and 10 days respectively. All patients required intensive support with a median duration of inpatient stay of 24 days. There was one treatment related death due to renal failure. One complete and two partial remissions (33% response rate) were seen but these were of short duration (median of 10 weeks). This study demonstrates that GM-CSF given by continuous intravenous infusion produces significant increments of peripheral granulocyte counts at 3 and 10 micrograms kg-1 day-1 and is not associated with any toxicity. The duration of neutropenia and thrombocytopenia induced by high-dose melphalan appears to be reduced by the subsequent administration of GM-CSF to times which are at least as short as have been reported in historical series which have used autologous bone marrow rescue
Dynamical Instabilities of the Randall-Sundrum Model
We derive dynamical equations to describe a single 3-brane containing fluid
matter and a scalar field coupling to the dilaton and the gravitational field
in a five dimensional bulk. First, we show that a scalar field or an arbitrary
fluid on the brane cannot evolve to cancel the cosmological constant in the
bulk. Then we show that the Randall-Sundrum model is unstable under small
deviations from the fine-tuning between the brane tension and the bulk
cosmological constant and even under homogeneous gravitational perturbations.
Implications for brane world cosmologies are discussed.Comment: 12 pages, 2 figure
THEORY OF PHASE-LOCKING IN SMALL JOSEPHSON JUNCTION CELLS
Within the RSJ model, we performed a theoretical analysis of phase-locking in
elementary strongly coupled Josephson junction cells. For this purpose, we
developed a systematic method allowing the investigation of phase-locking in
cells with small but non-vanishing loop inductance.The voltages across the
junctions are found to be locked with very small phase difference for almost
all values of external flux. However, the general behavior of phase-locking is
found to be just contrary to that according to weak coupling. In case of strong
coupling there is nearly no influence of external magnetic flux on the phases,
but the locking-frequency becomes flux-dependent. The influence of parameter
splitting is considered as well as the effect of small capacitive shunting of
the junctions. Strongly coupled cells show synchronization even for large
parameter splitting. Finally, a study of the behavior under external microwave
radiation shows that the frequency locking-range becomes strongly
flux-dependent, whereas the locking frequency itself turns out to be
flux-independent.Comment: 26 pages, REVTEX, 9 PS figures appended in uuencoded form at the end,
submitted to Phys. Rev. B
(G)hosting television: Ghostwatch and its medium
This article’s subject is Ghostwatch (BBC, 1992), a drama broadcast on Halloween night of 1992 which adopted the rhetoric of live non-fiction programming, and attracted controversy and ultimately censure from the Broadcasting Standards Council. In what follows, we argue that Ghostwatch must be understood as a televisually-specific artwork and artefact. We discuss the programme’s ludic relationship with some key features of television during what Ellis (2000) has termed its era of ‘availability’, principally liveness, mass simultaneous viewing, and the flow of the television super-text. We trace the programme’s television-specific historicity whilst acknowledging its allusions and debts to other media (most notably film and radio). We explore the sophisticated ways in which Ghostwatch’s visual grammar and vocabulary and deployment of ‘broadcast talk’ (Scannell 1991) variously ape, comment upon and subvert the rhetoric of factual programming, and the ends to which these strategies are put. We hope that these arguments collectively demonstrate the aesthetic and historical significance of Ghostwatch and identify its relationship to its medium and that medium’s history. We offer the programme as an historically-reflexive artefact, and as an exemplary instance of the work of art in television’s age of broadcasting, liveness and co-presence
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