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Full-Text Articles in Physical Sciences and Mathematics
Quantifying Fibronectin Adhesion With Nanoscale Spatial Resolution On Glycosaminoglycan Doped Polypyrrole Using Atomic Force Microscopy, Amy Gelmi, Michael J. Higgins, Gordon G. Wallace
Quantifying Fibronectin Adhesion With Nanoscale Spatial Resolution On Glycosaminoglycan Doped Polypyrrole Using Atomic Force Microscopy, Amy Gelmi, Michael J. Higgins, Gordon G. Wallace
Australian Institute for Innovative Materials - Papers
The interaction of ECM proteins is critical in determining the performance of materials used in biomedical applications such as tissue regeneration, implantable bionics and biosensing. Methods: To improve our understanding of ECM protein–conducting polymer interactions, we have used Atomic Force Microscopy (AFM) to elucidate the interactions of fibronectin (FN) on polypyrrole (PPy) doped with different glycosaminoglycans. Results: We were able to classify four main types of FN interactions, including those related to 1) non-specific adhesion, 2) protein unfolding and subsequent unbinding from the surface, 3) desorption and 4) interactions with no adhesion. FN adhesion on PPy/hyaluronic acid showed a significantly …
A Simple Post-Hoc Method To Add Spatial Context To Predictive Species Distribution Models, Michael B. Ashcroft, Kristine O. French, Laurie A. Chisholm
A Simple Post-Hoc Method To Add Spatial Context To Predictive Species Distribution Models, Michael B. Ashcroft, Kristine O. French, Laurie A. Chisholm
Faculty of Science - Papers (Archive)
Methods to incorporate spatial context into species distribution models (SDMs) are underutilised, with predictions usually based only on environmental space and ignoring geographic space. The goals of this study were to demonstrate a relatively simple post-hoc method to include spatial context in SDMs and to quantify the improvement over purely niche-based models. The method involved producing a standard niche-based model using established techniques, such as Maxent, and then calculating the neighbourhood average of the model output in geographic space. In effect, we tested whether the spatially averaged model output was better at predicting species distributions than the raw model output. …
Development Of A Spatial Data Infrastructure For Coastal Management In The Amirante Islands, Seychelles, Sarah M. Hamylton, Justin Prosper
Development Of A Spatial Data Infrastructure For Coastal Management In The Amirante Islands, Seychelles, Sarah M. Hamylton, Justin Prosper
Faculty of Science - Papers (Archive)
Spatial data infrastructures play a key role in coastal management decision making in the Seychelles. This paper describes four components of a web-based spatial data infrastructure that were developed to facilitate coastal management of the Amirante Islands in the Seychelles. The four components include: (i) the institutional arrangement for using spatial data effectively to address local management challenges, (ii) the production of island habitat maps from remotely sensed data, (iii) the tasks undertaken for promoting access to and use of this spatial data, and (iv) an example of how this data is used for a specific coastal management application in …
Spatial Modelling Of Benthic Cover Using Remote Sensing Data In The Aldabra Lagoon, Western Indian Ocean, Sarah Hamylton, Tom Spencer, A Hagan
Spatial Modelling Of Benthic Cover Using Remote Sensing Data In The Aldabra Lagoon, Western Indian Ocean, Sarah Hamylton, Tom Spencer, A Hagan
Faculty of Science - Papers (Archive)
Spatially explicit ecological modelling was used to predict the distribution of 4 benthic components (live coral, carbonate sand, macroalgae and dead coral) inside the Aldabra lagoon, southern Seychelles, western Indian Ocean. Both classic ordinary least-squares and spatial autoregression techniques were carried out on a field data set of 774 spatially referenced records and 3 satellite remote sensing images to define an empirical relationship between local environmental conditions (water depth and water level variation) and benthic cover. This relationship was then used to generate a synoptic model of the spatial cover and distribution of each benthic component at the landscape (i.e. …
A Spatial Analysis Of Multivariate Output From Regional Climate Models, Stephan Sain, Reinhard Furrer, Noel A. Cressie
A Spatial Analysis Of Multivariate Output From Regional Climate Models, Stephan Sain, Reinhard Furrer, Noel A. Cressie
Faculty of Informatics - Papers (Archive)
Climate models have become an important tool in the study of climate and climate change, and ensemble experiments consisting of multiple climate-model runs are used in studying and quantifying the uncertainty in climate-model output. However, there are often only a limited number of model runs available for a particular experiment, and one of the statistical challenges is to characterize the distribution of the model output. To that end, we have developed a multivariate hierarchical approach, at the heart of which is a new representation of a multivariate Markov random field. This approach allows for flexible modeling of the multivariate spatial …
Propagation Of Optical Spatial Solitary Waves In Bias-Free Nematic-Liquid-Crystal Cells, Antonmaria A. Minzoni, Luke W. Sciberras, Noel F. Smyth, Annette L. Worthy
Propagation Of Optical Spatial Solitary Waves In Bias-Free Nematic-Liquid-Crystal Cells, Antonmaria A. Minzoni, Luke W. Sciberras, Noel F. Smyth, Annette L. Worthy
Faculty of Informatics - Papers (Archive)
The propagation of a bulk optical solitary wave in a rectangular cell filled with a nematic liquid crystal—a nematicon—is mathematically modelled. In order to overcome the Freédricksz threshold the cell walls are rubbed to pretilt the nematic. A modulation theory, based on a Lagrangian formulation, is developed for the (2+1)-dimensional propagation of the solitary wave beam down the cell. This modulation theory is based on two different formulations of the director distribution. The relative advantages and disadvantages of these two methods are discussed. A previously unexplored method based on images is found to possess significant advantages. Excellent agreement with full …
A Spatial Agent-Based Model To Explore Scenarios Of Adaptation To Climate Change In An Alpine Tourism Destination, Stefano Balbi, Pascal Perez, Carlo Giupponi
A Spatial Agent-Based Model To Explore Scenarios Of Adaptation To Climate Change In An Alpine Tourism Destination, Stefano Balbi, Pascal Perez, Carlo Giupponi
SMART Infrastructure Facility - Papers
A vast body of literature suggests that the European Alpine region may be one of the most sensitive to climate change impacts. Adaptation to climate change of Alpine socioecosystems is increasingly becoming an issue of interest for the scientific community while the people of the Alps are often unaware of or simply ignore the problem. ClimAlpTour is a European research project of the Alpine Space Programme, bringing together institutions and scholars from all countries of the Alpine arch, in view of dealing with the expected decrease in snow and ice cover, which may lead to a rethinking of tourism development …
Spatial Variability Of Cadmium, Copper, Manganese, Nickel And Zinc In The Port Curtis Estuary, Queensland, Australia, Brad M. Angel, Leigh T. Hales, Stuart L. Simpson, Simon C. Apte, Anthony A. Chariton, Damon A. Shearer, Dianne F. Jolley
Spatial Variability Of Cadmium, Copper, Manganese, Nickel And Zinc In The Port Curtis Estuary, Queensland, Australia, Brad M. Angel, Leigh T. Hales, Stuart L. Simpson, Simon C. Apte, Anthony A. Chariton, Damon A. Shearer, Dianne F. Jolley
Faculty of Science - Papers (Archive)
Port Curtis is a rapidly growing industrialised and urbanised harbour in Central Queensland, Australia. Water sampling surveys were undertaken in late 2003 and 2004, accompanied by additional sediment sampling to investigate the sources and behaviour of trace metals, and the effects of pH on metal partitioning between dissolved and particulate forms. Sampling and analyses of trace metals in waters and suspended particulates were undertaken along axial transects extending away from possible point-sources within the harbour. Additional sampling was undertaken in selected inlets and major freshwater sources to Port Curtis, including the Fitzroy River. Most dissolved metal concentrations were significantly elevated …
Habitat Associations Of The Long-Nosed Potoroo (Potorous Tridactylus) At Multiple Spatial Scales, Melinda A. Norton, Kristine O. French, Andrew W. Claridge
Habitat Associations Of The Long-Nosed Potoroo (Potorous Tridactylus) At Multiple Spatial Scales, Melinda A. Norton, Kristine O. French, Andrew W. Claridge
Faculty of Science - Papers (Archive)
This study examined the coarse- and fine-scale habitat preferences of the long-nosed potoroo (Potorous tridactylus) in the Southern Highlands of New South Wales, in order to inform the management of this threatened species. Live-trapping was conducted in autumn and spring, from 2005 to 2008, at two sites. Macrohabitat preferences were examined by comparing trap success with numerous habitat attributes at each trap site. In spring 2007 and autumn 2008, microhabitat use was also examined, using the spool-and-line technique and forage digging assessments. While potoroos were trapped in a wide range of macrohabitats, they displayed some preference for greater canopy and …
Ranking Habitat Patches By Contribution To Network Connectivity: Tradeoffs Between Processing Time And Spatial Realisation, B Cook, Marjetta L. Puotinen, Rittick Borah
Ranking Habitat Patches By Contribution To Network Connectivity: Tradeoffs Between Processing Time And Spatial Realisation, B Cook, Marjetta L. Puotinen, Rittick Borah
Faculty of Science - Papers (Archive)
No abstract provided.
Spatial Ecology Of Hatchling Water Pythons (Liasis Fuscus) In Tropical Australia, Richard Shine, Thomas R. Madsen, Ligia Pizzatto, Gregory P. Brown
Spatial Ecology Of Hatchling Water Pythons (Liasis Fuscus) In Tropical Australia, Richard Shine, Thomas R. Madsen, Ligia Pizzatto, Gregory P. Brown
Faculty of Science - Papers (Archive)
Young snakes are rarely seen in the field and little is known about their habits. mostly because they are too small for radio-telemetry (the primary method for Studying snake spatial ecology). However, the offspring or some larger species can be fitted with transmitters and we investigated the spatial ecology and habitat use of ten hatchling water pythons (Liasis fuscus: Pythonidae) in the floodplain of the Adelaide River, tropical Australia. Patterns of habitat use in the late wet season and during the dry season were similar to those of adults tracked in the same vicinity in an earlier study. Soon after …
Spectral And Spatial Variation At Leaf And Patch Scale Of Invasive Wetland Weeds, Laurie A. Chisholm, John K. Marthick
Spectral And Spatial Variation At Leaf And Patch Scale Of Invasive Wetland Weeds, Laurie A. Chisholm, John K. Marthick
Faculty of Science - Papers (Archive)
The establishment of invasive weeds in wetland environments is a prominent threat in Australia with adverse impacts on native flora. Current management is hindered by the lack of information available on which to base and justify management interventions, in particular, mapping of weed distributions. Remote sensing is a possible solution to difficulties of this type as illustrated by its successful application to wetland mapping in general. This paper explores the potential of multiscale spectral reflectance to discriminate between two particularly offensive, invasive woody weeds, bitou bush (Chrysanthemoides monilifera ssp rotundata), and lantana (Lantana camara). Spectral reflectance at …
Spatial Ecology Of The Giant Burrowing Frog (Heleioporus Australiacus): Implications For Conservation Prescriptions, Trent D. Penman, F Lemckert, M J Mahony
Spatial Ecology Of The Giant Burrowing Frog (Heleioporus Australiacus): Implications For Conservation Prescriptions, Trent D. Penman, F Lemckert, M J Mahony
Faculty of Science - Papers (Archive)
Management of threatened anurans requires an understanding of a species’ behaviour and habitat requirements in both the breeding and non-breeding environments. The giant burrowing frog (Heleioporus australiacus) is a threatened species in south-eastern Australia. Little is known about its habitat requirements, creating difficulties in developing management strategies for the species.Weradio-tracked 33 individual H. australiacus in order to determine their habitat use and behaviour. Data from 33 frogs followed for between 5 and 599 days show that individuals spend little time near (<15 m) their breeding sites (mean 4.7 days for males and 6.3 days for females annually). Most time is spent in distinct non-breeding activity areas 20–250m from the breeding sites. Activity areas of females were further from the breeding site (mean 143 m) than those of males (mean 99 m), but were not significantly different in size (overall mean 500m2; males 553m2; females 307m2). Within activity areas, each frog used 1–14 burrows repeatedly, which weterm home burrows. Existing prescriptions are inappropriate for this species and we propose protection of key populations in the landscape as a more appropriate means of protecting this species.
Data Mining Of Misr Aerosol Product Using Spatial Statistics, Tao Shi, Noel A. Cressie
Data Mining Of Misr Aerosol Product Using Spatial Statistics, Tao Shi, Noel A. Cressie
Faculty of Informatics - Papers (Archive)
In climate models, aerosol forcing is the major source of uncertainty in climate forcing, over the industrial period. To reduce this uncertainty, instruments on satellites have been put in place to collect global data. However, missing and noisy observations impose considerable difficulties for scientists researching global aerosol distribution, aerosol transportation, and comparisons between satellite observations and global-climate-model outputs. In this paper, we propose a Spatial Mixed Effects (SME) statistical model to predict the missing values, denoise the observed values, and quantify the spatial-prediction uncertainties. The computations associated with the SME model are linear scalable to the number of data points, …
Anisotropic Matern Correlation And Spatial Prediction Using Reml, K A. Haskard, Brian R. Cullis, A P. Verbyla
Anisotropic Matern Correlation And Spatial Prediction Using Reml, K A. Haskard, Brian R. Cullis, A P. Verbyla
Faculty of Informatics - Papers (Archive)
The Mat´ern correlation function provides great flexibility for modeling spatially correlated random processes in two dimensions, in particular via a smoothness parameter, whose estimation allows data to determine the degree of smoothness of a spatial process. The extension to include anisotropy provides a very general and flexible class of spatial covariance functions that can be used in a model-based approach to geostatistics, in which parameter estimation is achieved via REML and prediction is within the E-BLUP framework. In this article we develop a general class of linear mixed models using an anisotropic Mat´ern class with an extended metric. The approach …
Spatial And Temporal Patterns Of Abundance And Recruitment Of Ghost Shrimp Trypaea Australiensis Across Hierarchical Scales In South-Eastern Australia, Douglas Rotherham, R. J. West
Spatial And Temporal Patterns Of Abundance And Recruitment Of Ghost Shrimp Trypaea Australiensis Across Hierarchical Scales In South-Eastern Australia, Douglas Rotherham, R. J. West
Faculty of Science - Papers (Archive)
Spatial and temporal variation in abundance and recruitment of burrowing ghost shrimp Trypaea australiensis was examined across 3 south-eastern Australian estuaries using a hierarchical sampling design, over a 2 yr period. We tested the hypothesis that abundances of shrimp were different between plots (10s to 100s of metres apart), sites within estuaries (kilometres apart), estuaries (100s of kilometres apart) and through time. More frequent sampling at 1 site also examined temporal variation at scales of months, seasons and years. Another aim was to investigate the reliability of using counts of burrow openings to indirectly measure the relative abundance of T, …
Sydney's Creative Economy: Social And Spatial Challenges, Christopher R. Gibson
Sydney's Creative Economy: Social And Spatial Challenges, Christopher R. Gibson
Faculty of Science - Papers (Archive)
The recent popularity of Richard Florida's work on the rise of the 'creative class' invites attention not only on the size and impact of the creative economy in Australia, but on its geography as well." At the core of Florida's approach is the premise that places compete with each other for a new kind of economic development, fuelled not by the availability of raw materials, cheap labour, or state investment in infrastructure, but by the decisions of producers in creative industries such as film, music, design and advertising to live and work in particular localities. Such creative producers constitute a …
Spatial Ecology Of Slatey-Grey Snakes (Stegonotus Cucullatus, Colubridae) On A Tropical Australian Floodplain, Gregory P. Brown, Richard Shine, Thomas Madsen
Spatial Ecology Of Slatey-Grey Snakes (Stegonotus Cucullatus, Colubridae) On A Tropical Australian Floodplain, Gregory P. Brown, Richard Shine, Thomas Madsen
Faculty of Science - Papers (Archive)
The extent, sequence, synchrony and correlates of diel displacements by animals can provide powerful insights into the ecological and social factors that shape an organism's day-to-day activities, but detailed data on spatial ecology are available for very few tropical taxa. Radiotelemetric monitoring of 25 slatey-grey snakes (Stegonotus cucullatus) on a floodplain in the Australian wet-dry tropics for periods of 40 to 355 d (mean=195 d, 136 locations per snake) provided extensive information on habitat use, movement patterns and home range size of these large slender-bodied colubrids. All radio-tracked animals were nocturnal, sheltering by day in soil cracks and …
Flexible Spatial Models For Kriging And Cokriging Using Moving Averages And The Fast Fourier Transform (Fft), Jay M. Ver Hoef, Noel A. Cressie, Ronald P. Barry
Flexible Spatial Models For Kriging And Cokriging Using Moving Averages And The Fast Fourier Transform (Fft), Jay M. Ver Hoef, Noel A. Cressie, Ronald P. Barry
Faculty of Informatics - Papers (Archive)
Models for spatial autocorrelation and cross-correlation depend on the distance and direction separating two locations, and are constrained so that for all possible sets of locations, the covariance matrices implied from the models remain nonnegative-definite. Based on spatial correlation, optimal linear predictors can be constructed that yield complete maps of spatial fields from incomplete and noisy spatial data. This methodology is called kriging if the data are of only one variable type, and it is called cokriging if it is of two or more variable types. Historically, to satisfy the nonnegative-definite condition, cokriging has used coregionalization models for cross-variograms, even …
Plenary: Nonparametric Hypothesis Testing For A Spatial Signal, Noel A. Cressie
Plenary: Nonparametric Hypothesis Testing For A Spatial Signal, Noel A. Cressie
Faculty of Informatics - Papers (Archive)
Summary form only given. Nonparametric hypothesis testing for a spatial signal can involve a large number of hypotheses. For instance, two satellite images of the same scene, taken before and after an event, could be used to test a hypothesis that the event has no environmental impact. This is equivalent to testing that the mean difference of "after-before" is zero at each of the (typically thousands of) pixels that make up the scene. In such a situation, conventional testing procedures that control the overall Type I error deteriorate as the number of hypotheses increase. Powerful testing procedures are needed for …
Spatial Statistics In The Presence Of Location Error With An Application To Remote Sensing Of The Environment, Noel A. Cressie, John Kornak
Spatial Statistics In The Presence Of Location Error With An Application To Remote Sensing Of The Environment, Noel A. Cressie, John Kornak
Faculty of Informatics - Papers (Archive)
Techniques for the analysis of spatial data have, to date, tended to ignore any effect caused by error in specifying the spatial locations at which measurements are recorded. This paper reviews the methods for adjusting spatial inference in the presence of data-location error, particularly for data that. have a continuous spatial index (geostatistical data). New kriging equations are developed and evaluated based on a simulation experiment. They are also applied to remote-sensing data from the Total Ozone Mapping Spectrometer instrument on the Nimbus-7 satellite, where the location error is caused by assignment of the data to their nearest grid-cell centers. …
Asymptotic Inference For Spatial Cdfs Over Time, Jun Zhu, S N. Lahiri, Noel A. Cressie
Asymptotic Inference For Spatial Cdfs Over Time, Jun Zhu, S N. Lahiri, Noel A. Cressie
Faculty of Informatics - Papers (Archive)
A spatial cumulative distribution function (SCDF) is a random function that provides a statistical summary of a random process over a spatial domain of interest. In this paper, we consider a spatio-temporal process and establish statistical methodology to analyze changes in the SCDF over time. We develop hypothesis testing to detect a difference in the spatial random processes at two time points, and we construct a prediction interval to quantify such discrepancy in the corresponding SCDFs. Using a spatial subsampling method, we show that our inferences are valid asymptotically. As an illustration, we apply these inference procedures to test and …
Spatial Mixture Models Based On Exponential Family Conditional Distributions, M Kaiser, Noel A. Cressie, J Lee
Spatial Mixture Models Based On Exponential Family Conditional Distributions, M Kaiser, Noel A. Cressie, J Lee
Faculty of Informatics - Papers (Archive)
Spatial statistical models are applied in many problems for which dependence in observed random variables is not easily explained by a direct scientific mechanism. In such situations there may be a latent spatial process that acts to produce the observed spatial pattern. Scientific interest often centers on the latent process and the degree of spatial dependence that characterizes it. Such latent processes may be thought of as spatial mixing distributions. We present methods for the specification of flexible joint distributions to model spatial processes through multi-parameter exponential family conditional distributions. One approach to the analysis of these models is Monte …
Fast, Resolution-Consistent Spatial Prediction Of Global Processes From Satellite Data, Hsin-Cheng Huang, Noel A. Cressie, John Gabrosek
Fast, Resolution-Consistent Spatial Prediction Of Global Processes From Satellite Data, Hsin-Cheng Huang, Noel A. Cressie, John Gabrosek
Faculty of Informatics - Papers (Archive)
Polar orbiting satellites remotely sense the earth and its atmosphere, producing datasets that give daily global coverage. For any given day, the data are many and measured at spatially irregular locations. Our goal in this article is to predict values that are spatially regular at different resolutions; such values are often used as input to general circulation models (GCMs) and the like. Not only do we wish to predict optimally, but because data acquisition is relentless, our algorithm must also process the data very rapidly. This article applies a multiresolution autoregressive tree-structured model, and presents a new statistical prediction methodology …
A Spatial-Temporal Statistical Approach To Command And Control Problems In Battle-Space Digitization, David A. Wendt, Noel A. Cressie, Gardar Johannesson
A Spatial-Temporal Statistical Approach To Command And Control Problems In Battle-Space Digitization, David A. Wendt, Noel A. Cressie, Gardar Johannesson
Faculty of Informatics - Papers (Archive)
There are considerable difficulties in the integration, visualization, and overall management of battle-space information for the purpose of Command and Control (C2). One problem that we see as being important is the timely combination of digital information from multiple (possibly disparate) sources in a dynamically evolving environment. That is, there is a need to assimilate incoming data rapidly, so as to provide the battle commander with up-to-date knowledge about the battle-space and thereby to facilitate the command-decision process. In this paper, we present a spatial-temporal approach to obtaining accurate estimates of the constantly changing battlefield, based on noisy data from …
A Spatial Analysis Of Variance Applied To Soil-Water Infiltration, C Gotway, Noel A. Cressie
A Spatial Analysis Of Variance Applied To Soil-Water Infiltration, C Gotway, Noel A. Cressie
Faculty of Informatics - Papers (Archive)
A spatial analysis of variance uses the spatial dependence among the observations to modify the usual interference procedures associated with a statistical linear model. When spatial correlation is present, the usual tests for presence of treatment effects may no longer be valid, and erroneous conclusions may result from assuming that the usual F ratios are F distributed. This is demonstrated using a spatial analysis of soil-water infiltration data. Emphasis is placed on modeling the spatial dependence structure with geostatistical techniques, and this spatial dependence structure is then used to test hypotheses about fixed effects using a nested linear model. -Authors
A Robust-Resistant Spatial Analysis Of Soil Water Infiltration., Noel A. Cressie, R Horton
A Robust-Resistant Spatial Analysis Of Soil Water Infiltration., Noel A. Cressie, R Horton
Faculty of Informatics - Papers (Archive)
Concentrates on estimating the spatial correlations between soil water infiltration observations, with special emphasis on resistant methods to remove nonstationarity. After this removal, robust semivariogram estimators are used to examine the spatial dependencies for various tillage treatments. There is some indication that infiltration characteristics inherit different types of spatial dependency, depending on the tillage treatment applied.-from Authors