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Incorporating novelty and novel ecosystems into restoration planning and practice in the 21st century

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Ecological processes 2013年第1期2卷 175-182页

作者： Michael p perring Rachel J Standish Richard J hobbs Ecosystem Restoration and Intervention Ecology Research Group School of Plant BiologyThe University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

Novelty pervades the *** some cases,potentially irreversible abiotic and/or biotic changes have led to the crossing of thresholds and thus the formation of“novel ecosystems.”Their widespread emergence(particularly on land)and the presence of continued environmental change challenge a traditional restoration goal of restoring an historical ***,we argue that restoration could broaden its frame of reference to consider how novel ecosystems might be used to maintain global biodiversity and provide ecosystem services and,in doing so,save potentially wasted efforts in attempting to fulfil traditional *** we explore this contention in more depth by addressing:Are novel ecosystems innovative planning or lowering the bar?We show that novel ecosystems were not innovative planning in their original *** the contrary,they were recognized as ecosystems that were recalcitrant to traditional restoration approaches,coupled with an awareness that they had arisen inadvertently through deliberate human activity,either on-or *** recalcitrance to traditional restoration suggests that alternative goals may exist for these ecosystems using sometimes innovative *** management may include biodiversity conservation or restoration for ecological *** elucidate the latter aspect with reference to an experiment in the wheatbelt of Western Australia—The Ridgefield Multiple Ecosystem Services Experiment—the design of which has been informed by ecological theory and the acceptance of novelty as an ecosystem *** novel ecosystems do provide opportunities to broaden restoration planning and practice,and ultimately maintain and conserve global biodiversity in this era of environmental change,they necessarily“lower the bar”in restoration if the bar is considered to be the historical ***,in these times of flux,such a bar is increasingly ***,careful and appropriate interventions are required

关键词： No-analogue ecosystem Biodiversity conservation Ecosystem function Ecological restoration Restoration baseline Ridgefield multiple ecosystem services experiment York gum woodland

Effects of porosity heterogeneity on chemical dissolution-front instability in fluid-saturated rocks

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Journal of Central South University 2017年第3期24卷 720-725页

作者： ZHAO Chong-bin peter SCHAUBS Bruce hobbs Computational Geosciences Research Centre Central South University Changsha 410083 China CSIRO Mineral Resource National Research Flagship R O. Box 1130 Bentley WA 6102 Australia School of Earth and Environment The University of Western Australia Crawley WA 6009 Australia

Homogeneity and heterogeneity are two totally different concepts in *** the particle length scale,rocks exhibit strong heterogeneity in their constituents and *** the heterogeneity of porosity obeys the random uniform distribution,both the mean value and the variance of porosities in the heterogeneous porosity field can be used to reflect the overall heterogeneous characteristics of the porosity *** main purpose of this work is to investigate the effects of porosity heterogeneity on chemical dissolution front instability in fluid-saturated rocks by the computational simulation *** related computational simulation results have demonstrated that:1) since the propagation speed of a chemical dissolution front is inversely proportional to the difference between the final porosity and the mean value of porosities in the initial porosity field,an increase in the extent of the porosity heterogeneity can cause an increase in the mean value of porosities in the initial porosity field and an increase in the propagation speed of the chemical dissolution front.2) An increase in the variance of porosities in the initial porosity field can cause an increase in the instability probability of the chemical dissolution front in the fluid-saturated rock.3) The greater the mean value of porosities in the initial porosity field,the quicker the irregular morphology of the chemical dissolution front changes in the supercritical chemical dissolution *** means that the irregular morphology of a chemical dissolution front grows quicker in a porosity field of heterogeneity than it does in that of homogeneity when the chemical dissolution system is at a supercritical stage.

关键词： porosity heterogeneity chemical dissolution front instability computational simulation porous rocks

Investigating dynamic mechanisms of geological phenomena using methodology of computational geosciences:An example of equal-distant mineralization in a fault

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Science China Earth Sciences 2008年第7期51卷 947-954页

作者： B.E.hobbs A.ORD CSIRO Division of Exploration and Mining P. O. Box 1130 Bentley WA 6102 Australia

This paper presents a research methodology associated with approximately a decade old computa- tional geosciences. To demonstrate how it can be used to investigate the dynamic mechanisms of geological phenomenon, we use as an example the equal-distant distribution of gold deposits in a three-dimensional permeable fault within the Yilgarn Craton, Western Australia. The related numerical results demonstrate that: (1) convective pore-fluid flow in fluid-saturated porous media is the control- ling dynamic mechanism leading to the equal-distant distribution of gold deposits along the fault; (2) the main characteristic of the new methodology is to change the traditionally used empirical, descrip- tive and qualitative methodology into the fundamentally scientific principles based predictive and quantitative methodology. Thus, this new methodology provides a modern scientific research tool for investigating the dynamic mechanisms associated with observed geological phenomena in nature.

关键词： computational geosciences research methodology geological phenomena dynamic mechanisms

Biodiversity change in heathland and its relationships with shifting local fire regimes and native species expansion

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Journal of plant Ecology 2015年第1期8卷 17-29页

作者： Nancy Shackelford Michael Renton Michael p.perring Kristine Brooks Richard J.hobbs School of plant Biology The University of Western Australia(M090)35 Stirling HighwayCrawleyWestern Australia 6009Australia Centre of Excellence for Climate Change Forest and Woodland HealthMurdoch UniversityMurdochWestern Australia 6150Australia Department of Environment and Conservation Great Southern District OfficePO Box 100NarroginWestern Australia 6312Australia

Aims Understanding the relationships among disturbance,invasion and species change is essential for effective management of many *** investigated relationships among fire history,invasion by a native tree species,Allocasuarina huegeliana,and diversity change to understand the potential drivers of plant community alteration in a complex and biodiverse *** We used plant species surveys from 1983 and 2011 to quantify spe-cies loss/gain and thence compositional ***,we surveyed population densities of the invasive species and collated long-term fire history data for each *** linear models and non-parametric models were used to assess the strength of relation-ships between the three variables of *** Findings Within the last 30 years,~11%of the plant species richness was lost from the *** an individual site level,we found only a 4%average decrease in overall plant species richness,but large species losses and gains that imply considerable compositional *** such shifts might be expected over 30 years,many of the gained species were common,potentially opportunistic species,while those lost were often locally rare woody *** addi-tion,gained species tended to be expanding their recorded range westward suggesting that they may be responding to the regional drying *** relationship between invasion density and spe-cies loss was strong over all spatial *** identified a poten-tial state change to dominance by the native invasive particularly as high densities prevented species gain at the site *** these extreme cases of high invasive density and high biodiversity loss,we argue that there may be a need to directly address the expanding native population.

关键词： kwongan sandplain heath Allocasuarina huegeliana native invasion woody encroachment

Distortion-stabilized ordered structures in A_(2)BB’O_(7) mixed pyrochlores

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npj Computational Materials 2019年第1期5卷 1076-1084页

作者： Ghanshyam pilania brian puchala Blas p.Uberuaga Materials Science and Technology Division Los Alamos National LaboratoryLos AlamosNM 87545USA Materials Science and Engineering Department University of MichiganAnn ArborMI 48109USA

pyrochlore oxides(A2B2O7)are interesting for a number of technological applications,including radiation damage tolerance and as ionic *** pyrochlores—containing two A and/or two B site cations—provide even more flexibility for tailoring properties owing to the diverse chemical and configurational degrees of freedom accessible within this chemical ***,we examine relative stability of different cation orderings in one model double pyrochlore Gd2(Zr_(x)Ti_(1−x))_(2)O_(7),as a function of Zr content *** results show that,in the presence of some very specific local cation arrangements,certain cation-ordered compositions in this system are highly stabilized as a result of large oxygen relaxation displacements,leading to the formation of an ordered‘double’pyrochlore *** origins of these anomalous oxygen relaxations are traced back to both the local cation symmetry and a strong chemical preference of Zr atoms towards adopting a 7-fold coordination environment,as opposed to a 6-fold coordination available in a regular pyrochlore ***,we examine the stability of this type of ordering in 131 other pyrochlore *** of our findings are discussed in relation to the observed composition-dependent ionic conductivity in these systems and connections with previously reported experimental findings are made.

关键词： structure ordered stabilized

Multilineage Differentiation of Dental pulp Stem Cells from Green Fluorescent protein Transgenic Mice

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International Journal of Oral Science 2010年第1期2卷 21-27页

作者： brian E.Grottkau p.prasad purudappa Department of Orthopaedic Surgery Mass General Hospital for Children and the Pediatric Orthopaedic Laboratory for Tissue EngineeringHarvard Medical School

Aim The aim of this study was to confirm the multilineage differentiation ability of dental pulp stem cells （DpSCs） from green fluorescent protein （GFp） transgenic mice. The expression of GFp in DpSCs was also observed during differentiation. Methodology DpSCs were harvested from the dental pulp tissue of transgenic nude mice, and then transferred to osteogenic, adipogenic, and chondrogenic media. The morphological characterization of induced cells was observed by microscopy and histological staining. The expression of marker genes was measured by RT-pCR. Results The endogenous GFp and multilineage potential of transgenic DpSCs had no influence on each other. Moreover, the results of fluorescence microscopic imaging suggest that there was no significant decline of GFp expression during DpSCs differentiation. Conclusion As the population of GFp labeled DpSCs can be easily identified, this will be a promising method for tracking DpSCs in vivo.

关键词： dental pulp stem cells multilineage differentiation green fluorescent protein

A Flux Based Approximation to Simulate Coupled Hydromechanical problems for Mines with Heterogeneous Rock Types Using the Material point Method

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Computer Modeling in Engineering & Sciences 2022年第4期131卷 379-409页

作者： Gysbert Basson Andrew p.Bassom brian Salmon Institute of Mine Seismology and University of Tasmania Kingston7050Australia School of Natural Sciences-University of Tasmania Sandy BayHobart7001Australia School of Engineering-University of Tasmania Sandy BayHobart7001Australia

Advances in numerical simulation techniques play an important role in helpingmining engineers understand those parts of the rock mass that cannot be readily *** Material point Method(MpM)is an example of such a tool that is gaining popularity for studying geotechnical *** recent years,the original formulation of MpM has been extended to not only account for simulating the mechanical behaviour of rock under different loading conditions,but also to describe the coupled interaction of pore water and solid phases in *** methods assume that the permeability of mediums is homogeneous,and we show that these MpM techniques fail to accurately capture the correct behaviour of the fluid phase if the permeability of the material is *** this work,we propose a novel implementation of the coupled MpM to address this *** employ an approach commonly used in coupled Finite Volume Methods,known as the Two point Flux Approximation(TpFA).Our new method is benchmarked against two well-known analytical expressions(a one-dimensional geostatic consolidation and the so-called Mandel-Cryer effect).Its performance is compared to existing coupled MpM approaches for homogeneous *** order to gauge the possible effectiveness of our technique in the field,we apply ourmethod to a case study relating to a mine known to experience severe problems with pore water.

关键词： Fluid permeability Material point Method mining faults

Leveraging quasi-periodic orbits for trajectory design in cislunar space

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Astrodynamics 2021年第2期5卷 139-165页

作者： brian p.McCarthy Kathleen C.Howell School of Aeronautics and Astronautics Neil Armstrong Hall of EngineeringWest LafayetteIN47907-2045USA

Incorporating quasi-periodic orbits into the preliminary design process offers a wide range of options to meet mission constraints and address the challenges in a complex trade *** this investigation,linear stability and quasi-periodic orbit family continuation schemes are examined to meet various types of *** in eclipse avoidance and transfer design are examined by leveraging quasi-periodic orbits and their associated hyperbolic manifolds in the lunar *** are transitioned to an ephemeris model to validate that geometries are maintained in higher-fidelity *** the natural dynamical structures associated with quasi-periodic orbits are leveraged,novel trajectory solutions can emerge.

关键词： multi-body dynamical systems quasi-periodic orbits trajectory analysis cislunar trajectory design near rectilinear halo orbit ephemeris dynamical model

Effective loading algorithm associated with explicit dynamic relaxation method for simulating static problems

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Journal of Central South University 2009年第1期16卷 125-130页

作者：赵崇斌彭省临刘亮明 hobbs B E ORD A Computational Geosciences Research Centre Central South University CSIRO Division of Exploration and Mining P. O. Box 1130

Based on the fact that a static problem has an equivalent wave speed of infinity and a dynamic problem has a wave speed of finite value, an effective loading algorithm associated with the explicit dynamic relaxation method was presented to produce meaningful numerical solutions for static problems. The central part of the explicit dynamic relaxation method is to turn a time-independent static problem into an artificial time-dependent dynamic problem. The related numerical testing results demonstrate that: (1) the proposed effective loading algorithm is capable of enabling an applied load in a static problem to be propagated throughout the whole system within a given loading increment, so that the time-independent solution of the static problem can be obtained; (2) the proposed effective loading algorithm can be straightforwardly applied to the particle simulation method for solving a wide range of static problems.

关键词： numerical simulation static systems dynamic relaxation loading algorithm