Macquarie University

About: Macquarie University is a education organization based out in Sydney, New South Wales, Australia. It is known for research contribution in the topics: Population & Context (language use). The organization has 14075 authors who have published 47673 publications receiving 1416184 citations. The organization is also known as: Macquarie uni.

Bursting the bubble of ballooning plutons: A return to nested diapirs emplaced by multiple processes

Abstract: A popular model for the emplacement of roughly spherical plutons is that of “ballooning” or in situ inflation of a magma chamber. In a common version of this model magma ascends until loss of heat or buoyancy causes the outermost magma to crystallize and cease ascent, while the hotter “tail” of magma continues to rise and expand the already crystallized outer margin. This expansion forms a concentric, gneissic to mylonitic foliation and flattening-type strain in the outer margin of the pluton by means of subsolidus deformation and pushes aside the surrounding country rock to form a dynamothermal aureole that postdates regional structures. Our reexamination of three supposedly ballooned plutons (Ardara, Ireland; Cannibal Creek, Australia; Papoose Flat, California) and evaluation of published descriptions of many others indicate that this model is largely incorrect. Deflections of country-rock structures, strains, and porphyroblast-matrix relationships indicate that only minor to moderate expansion (usually 30% or less) occurred during emplacement, that other emplacement mechanisms must have occurred, and that regional deformation continued during and after emplacement. Internal structures indicate that when magma chamber expansion did occur, it did so by flow of magma, that magmatic foliations and lineations formed late in the magma chamber evolution, that enclave shapes are neither good strain markers nor indicators of the magnitude of expansion, and that only minor internal subsolidus deformation results from emplacement. This study indicates that many plutons previously interpreted as post-tectonic ballooning plutons are better viewed as syntectonic, nested diapirs emplaced by a variety of country-rock material-transfer processes. This nested diapir model implies that magma ascent may occur by rise of large magma batches (instead of transport in dikes followed by ballooning), that magma chamber dynamics differ from that in the ballooning model, and that normally zoned plutons may form by intrusion of several pulses of magma rather than by in situ crystal fractionation from a single parent melt.

Public sector knowledge management : a structured literature review

Abstract: Purpose – This paper aims to review and critique the public sector knowledge management (KM) literature, offers an overview of the state of public sector KM research and outlines a future research agenda. Design/methodology/approach – Articles published in KM journals are analyzed using a structured literature review methodology. The paper analyzes 180 papers published within ten journals specializing in the field of KM. Findings – Public sector KM is a research area of growing importance. Findings show that few authors specialize in the field and there are several obstacles to developing a cohesive body of literature. Low levels of international cooperation among authors and international comparisons mean that the literature is fragmented. Some research topics and some geographical areas within the public sector theme are over-analyzed, while others are under-investigated. Additionally, academic researchers should re-think their methodological approach if they wish to make significant contributions to th...

A biopsy system for small cetaceans: darting success and wound healing in tursiops spp.

Abstract: Together with PAXARMS (NZ), we developed a biopsy system for small cetaceans and tested it on four populations of bottlenose dolphins (Tursiops spp.). The system consists of a modified 0.22 caliber rifle, and biopsy darts made out of polycarbonate with stainless steel biopsy tips. Animals were darted at a range of 2-15 m while travelling parallel to the vessel. Overall sampling success for obtaining biopsy samples when an animal was struck ranged from 96.6% to 100% in the four populations. However, hit rate varied for the four different populations. We did not observe a significant difference in strength of the reaction to the darting procedure when an animal was hit or missed, both among and within populations. Data from one population showed no significant difference in the reaction to biopsy sampling by four different age-sex classes. The only factor that had a significant influence on darting success was the hit location. Furthermore, we observed a significant positive correlation between the size of the sample obtained and the reaction to biopsy sampling. Biopsy samples were sufficient for microsatellite and d-loop analysis in 95.8% and for genetic sexing in 99% of all cases. In animals that we observed on a daily basis, wounds were healed after approximately 23 d.

Testing for Multiple Bubbles: Limit Theory of Real Time Detectors

Abstract: This paper provides the limit theory of real time dating algorithms for bubble detection that were suggested in Phillips, Wu and Yu (2011, PWY) and Phillips, Shi and Yu (2013b, PSY). Bubbles are modeled using mildly explosive bubble episodes that are embedded within longer periods where the data evolves as a stochastic trend, thereby capturing normal market behavior as well as exuberance and collapse. Both the PWY and PSY estimates rely on recursive right tailed unit root tests (each with a different recursive algorithm) that may be used in real time to locate the origination and collapse dates of bubbles. Under certain explicit conditions, the moving window detector of PSY is shown to be a consistent dating algorithm even in the presence of multiple bubbles. The other algorithms are consistent detectors for bubbles early in the sample and, under stronger conditions, for subsequent bubbles in some cases. These asymptotic results and accompanying simulations guide the practical implementation of the procedures. They indicate that the PSY moving window detector is more reliable than the PWY strategy, sequential application of the PWY procedure and the CUSUM procedure.

The determination of view-factors in urban canyons

Abstract: An important aspect of longwave radiation exchange within urban canopies is the degree to which the sky is obscured by surrounding buildings, a concept which may be described by the sky view-factor (ψs). Hitherto, expressions for sky view-factors in the urban context have been derived for symmetrical urban canyons of infinite length. In this paper an analytical expression is presented which permits the determination of sky view-factors for the more realistic case of urban canyons in which buildings are irregularly aligned and of finite length.