Certain Phases (certain + phase)

Distribution by Scientific Domains


Selected Abstracts


The intersection of scientific and indigenous ecological knowledge in coastal Melanesia: implications for contemporary marine resource management*

INTERNATIONAL SOCIAL SCIENCE JOURNAL, Issue 187 2006
Simon Foale
Fundamental differences in the worldviews of western marine scientists and coastal Melanesian fishers have resulted in very different conclusions being drawn from similar sets of observations. The same inductive logic may lead both scientists and indigenous fishers to conclude that, say, square-tail trout aggregate at a certain phase of the moon in a certain reef passage, but different assumptions derived from disparate worldviews may lead to very different conclusions about why the fish are there. In some cases these differences have significant implications for the way marine resources are (or are not) exploited and managed. Here I analyse examples of what I call empirical gaps in both scientific and indigenous knowledge concerning the biology and ecology of fished organisms that in some cases have led to the poor management of stocks of these species. I argue that scientific education can complement indigenous knowledge systems and thus lead to improved resource management, despite some claims that scientific and indigenous knowledge systems are incommensurable. [source]


Specification, planning, and execution of QoS-aware Grid workflows within the Amadeus environment

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 4 2008
Ivona Brandic
Abstract Commonly, at a high level of abstraction Grid applications are specified based on the workflow paradigm. However, majority of Grid workflow systems either do not support Quality of Service (QoS), or provide only partial QoS support for certain phases of the workflow lifecycle. In this paper we present Amadeus, which is a holistic service-oriented environment for QoS-aware Grid workflows. Amadeus considers user requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment workflows and the associated QoS constraints are specified at a high level using an intuitive graphical notation. A distinguishing feature of our system is the support of a comprehensive set of QoS requirements, which considers in addition to performance and economical aspects also legal and security aspects. A set of QoS-aware service-oriented components is provided for workflow planning to support automatic constraint-based service negotiation and workflow optimization. For improving the efficiency of workflow planning we introduce a QoS-aware workflow reduction technique. Furthermore, we present our static and dynamic planning strategies for workflow execution in accordance with user-specified requirements. For each phase of the workflow lifecycle we experimentally evaluate the corresponding Amadeus components. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Exploratory Analysis of Similarities in Solar Cycle Magnetic Phases with Southern Oscillation Index Fluctuations in Eastern Australia

GEOGRAPHICAL RESEARCH, Issue 4 2008
ROBERT G.V. BAKER
Abstract There is growing interest in the role that the Sun's magnetic field has on weather and climatic parameters, particularly the ~11 year sunspot (Schwab) cycle, the ~22 yr magnetic field (Hale) cycle and the ~88 yr (Gleissberg) cycle. These cycles and the derivative harmonics are part of the peculiar periodic behaviour of the solar magnetic field. Using data from 1876 to the present, the exploratory analysis suggests that when the Sun's South Pole is positive in the Hale Cycle, the likelihood of strongly positive and negative Southern Oscillation Index (SOI) values increase after certain phases in the cyclic ~22 yr solar magnetic field. The SOI is also shown to track the pairing of sunspot cycles in ~88 yr periods. This coupling of odd cycles, 23,15, 21,13 and 19,11, produces an apparently close charting in positive and negative SOI fluctuations for each grouping. This Gleissberg effect is also apparent for the southern hemisphere rainfall anomaly. Over the last decade, the SOI and rainfall fluctuations have been tracking similar values to that recorded in Cycle 15 (1914,1924). This discovery has important implications for future drought predictions in Australia and in countries in the northern and southern hemispheres which have been shown to be influenced by the sunspot cycle. Further, it provides a benchmark for long-term SOI behaviour. [source]


Petrogenetic modelling of strongly residual metapelitic xenoliths within the southern Platreef, Bushveld Complex, South Africa

JOURNAL OF METAMORPHIC GEOLOGY, Issue 3 2010
T. E. JOHNSON
Abstract Xenoliths of quartz-absent Fe-rich aluminous metapelite are common within the platinum group element-rich mafic/ultramafic magmatic rocks of the Platreef. Relative to well-characterized protoliths, the xenoliths are strongly depleted in K2O and H2O, and have lost a substantial amount of melt (>50 vol.%). Mineral equilibria calculations in the NCKFMASHTO system yield results that are consistent with observations in natural samples. Lower-grade rocks that lack staurolite constrain peak pressures to ,2.5 kbar in the southern Platreef. Smaller xenoliths and the margins of larger xenoliths comprise micro-diatexite rich in coarse acicular corundum and spinel, which record evidence for the metastable persistence of lower-grade hydrous phases and rapid melting consequent on a temperature overstep of several hundred degrees following their incorporation in the mafic/ultramafic magmas. In the cores of larger xenoliths, temperatures increased more slowly enabling progressive metamorphism by continuous prograde equilibration and the loss of H2O by subsolidus dehydration; the H2O migrated to xenolith margins where it may have promoted increased melting. According to variations in the original compositional layering, layers became aluminosilicate- and/or cordierite-rich, commonly with spinel but only rarely with corundum. The differing mineralogical and microstructural evolution of the xenoliths depends on heating rates (governed by their size and, therefore, proximity to the Platreef magmas) and the pre-intrusive metamorphic grade of the protoliths. The presence or absence of certain phases, particularly corundum, is strongly influenced by the degree of metastable retention of lower-grade hydrates in otherwise identical protolith bulk compositions. The preservation of fine-scale compositional layering that is inferred to be relict bedding in xenolith cores implies that melt loss by compaction was extremely efficient. [source]