Physical Sciences and Mathematics Commons^™

Preparing Cs Honours Students For A Research Career: The Wollongong Experience, John Fulcher, Ian Piper

Dr Ian Piper

No abstract provided.

Editorial: High-Tech Lust, Katina Michael

Professor Katina Michael

Are you in love with your Android or Apple device? Do you have a deep affection and suffer from separation anxiety [1] when your smartphone is not within arm’s length of your bed at night?

Don’t worry, you’re not alone. Rossiter [1] differentiates between “brand love” and “brand liking” which is significant. When it comes to our high-tech gadgetry people are likely to be able to cope better with being separated from a partner or child than being separated from a vital piece of technology which goes with them everywhere.

Automatic Left Ventricle Detection In Echocardiographic Images For Deformable Contour Initialization, Cher Hau Seng, Ramazan Demirli, Moeness G. Amin, Jason L. Seachrist, Abdesselam Bouzerdoum

Cher Hau Seng

The accurate left ventricular boundary detection in echocardiographic images allow cardiologists to study and assess cardiomyopathy in patients. Due to the tedious and time consuming manner of manually tracing the borders, deformable models are generally used for left ventricle segmentations. However, most deformable models require a good initialization, which is usually outlined manually by the user. In this paper, we propose an automated left ventricle detection method for two-dimensional echocardiographic images that could serve as an initialization for deformable models. The proposed approach consists of pre-processing and post-processing stages, coupled with the watershed segmentation. The pre-processing stage enhances the overall …

Seizure Detection In Eeg Signals Using Support Vector Machines, Cher Hau Seng, Ramazan Demirli, Lunal Khuon, Donovan Bolger

Cher Hau Seng

A linear Support Vector Machine (SVM) classifier is designed to detect and classify seizures in EEG signals based on a few simple features such as mean, variance, dominant frequency, and the mean power spectrum. The SVM classifier is tested on a benchmark EEG database. Using a combination of these features, classification rates up to 98% were achieved. The proposed classifier that utilizes a few simple features is computationally efficient to be deployed in a real-time seizure monitoring system.

A Gaussian-Rayleigh Mixture Modeling Approach For Through-The-Wall Radar Image Segmentation, Cher Hau Seng, Abdesselam Bouzerdoum, Moeness Amin, F Ahmad

Cher Hau Seng

In this paper, we propose a Gausssian-Rayleigh mixture modeling approach to segment indoor radar images in urban sensing applications. The performance of the proposed method is evaluated on real 2D polarimetric data. Experimental results show that the proposed method enhances image quality by distinguishing between target and clutter regions. The proposed method is also compared to an existing Neyman-Pearson (NP) target detector that has been recently devised for through-the-wall radar imaging. Performance evaluation of both methods shows that the proposed method outperforms the NP detector in enhancing the input images.

Person-Level And Household-Level Regression Estimation In Household Surveys, David Steel, Robert Clark

Robert Clark

A common class of survey designs involves selecting all people within selected households. Generalized regressionestimators can be calculated at either the person or household level. Implementing the estimator at the household level has the convenience of equal estimation weights for people within households. In this article the two approaches are compared theoretically and empirically for the case of simple random sampling of households and selection of all persons in each selected household. We find that the household level approach is theoretically more efficient in large samples and any empirical inefficiency in small samples is limited.

Comments On Sample Design For Proposed Australian Asthma Survey, Robert Clark

Robert Clark

The proposed design for the Australian Asthma Survey involves: a phone or face-toface screening interview with approximately 20,000 responding adults, followed by an in-depth interview and objective testing of all asthmatics and 1/10th of nonasthmatics in the screen. This report elaborates on sample design options based on the aims and approaches in the Australian Asthma Survey Proposal. The main requirement affecting the sample design is the need for a relatively small number of objective testing centres to be able to service the whole sample. This report considered a number of options where the sample was clustered in only 25 Statistical …

Oxygen Exchange During The Reaction Of Pocl3 And Water, Robert Clark, Robert Morrison, Andrew Thomas, Rebeca Alvarez, Paul Milham

Robert Clark

To investigate O exchange during the reaction of POCl3 and water, natural abundance POCl3 was reacted with water highly enriched in 18O, and the resulting H3PO4 was isolated as KH2PO4. This reaction was conducted with and without tetrahydrofuran (THF) as a solvent, and was controlled in THF and violent in its absence. Approximately 5 x 10-4M aqueous solutions of the KH2PO4 were analyzed using electrospray ionization mass spectrometry, to estimate the proportions of the mass-clumped 16,17,18O isotope analogues of [H2PO4] -. During analysis, ~29% of [H2PO4] - dehydrated to [PO3]-, for which the proportions of the O isotope analogues were …

Robust Resampling Confidence Intervals For Empirical Variograms, Robert Clark, Samuel Allingham

Robert Clark

The variogram function is an important measure of the spatial dependenciesof a geostatistical or other spatial dataset. It plays a central role in kriging, designingspatial studies, and in understanding the spatial properties of geological andenvironmental phenomena. It is therefore important to understand the variability attachedto estimates of the variogram. Existing methods for constructing confidenceintervals around the empirical variogram either rely on strong assumptions, such asnormality or known variogram function, or are based on resampling blocks and subjectto edge effect biases. This paper proposes two new procedures for addressingthese concerns: a quasi-block-bootstrap and a quasi-block-jackknife. The new methodsare based on transforming …

Sampling Within Households In Household Surveys, Robert Clark, David Steel

Robert Clark

The number of people to select within selected households has significant consequences for the conduct and output of household surveys. The operational and data quality implications of this choice are carefully considered in many surveys, but the impact on statistical efficiency is not well understood. The usual approach is to select all people in each selected household, where operational and data quality concerns make this feasible. If not, one person is usually selected from each selected household. We find that this strategy is not always justified, and develop intermediate designs between these two extremes. Current practices were developed when household …

Preliminary Sample Design For The New Zealand Health Survey 2010, Robert Clark

Robert Clark

This report describes the choice of the preliminary design for the New Zealand Health Survey, to be implemented from 2011. The survey will use computer assisted personal interviewing. The sample will be selected using a multi-stage area design. The selected sample size will be around 12,000 people per year. This is envisaged as sufficient to provide adequate precision for estimates of key prevalences for adults and children. The main objectives of the sample design are: • The design should support analysis of the survey by multiple users, which implies avoiding great variation in estimation weights. • Estimates for children and …

Accounting For The Uncertainty Of Information On Clustering In The Design Of A Clustered Sample, David Steel, Robert Clark

Robert Clark

An important decision that has to be made in developing the design of a cluster or multi-stage sampling scheme is the number of units to select at each stage of selection. For a two-stage design we need to decide the number of units to select from each Primary Sampling Unit (PSU) in the sample. A common approach is to estimate the costs and the variance components associated with each stage of selection and determine an optimal design. This is usually done for estimates of the means or totals of one or a small number of variables. In practice the measure …

The Effect Of Using Household As A Sampling Unit, Robert Clark, David Steel

Robert Clark

The effect of sampling people through households is considered. Results on design effects for two stage surveys are reviewed and applied to give design effects of household samples. The main factors that determine the design effect are identified for the designs in which one person, or all people, are selected from each selected household.Within household correlation is one factor.We show that the relationships between household size and the mean and variance within households are also important factors. Census and survey data are used to empirically compare the design effects for a range of estimators, variables and designs.

Conditional And Unconditional Models In Model-Assisted Estimation Of Finite Population Totals, David Steel, Robert Clark

Robert Clark

The well known Godambe-Joshi lower bound for the anticipated variance of design unbiased estimators of population totals treats the auxiliary variables as constants. We extend the result to models where these variables are random and show that the generalized difference estimator using the expected values conditional on all auxiliary values is optimal. This has several implications including the fact that collecting multiple survey variables does not reduce the lower bound.

Adaptive Inference For Multi-Stage Survey Data, Loai Alzoubi, Robert Clark, David Steel

Robert Clark

Multi-level models can be used to account for clustering in data from multi-stage surveys. In some cases, the intraclass correlation may be close to zero, so that it may seem reasonable to ignore clustering and fit a single-level model. This article proposes several adaptive strategies for allowing for clustering in regression analysis of multi-stage survey data. The approach is based on testing whether the PSU-level variance component is zero. If this hypothesis is retained, then variance estimates are calculated ignoring clustering; otherwise, clustering is reflected in variance estimation. A simple simulation study is used to evaluate the various procedures.

Soil Chemistry: Understanding Phosphorus In The Environment, Paul Milham, Warwick Dougherty, Robert Morrison, Robert Clark, Ronald Smernik, Ashlea Doolette, Lucy Burkitt, Damian Collins, Rebeca Alvarez, Andrew Thomas

Robert Clark

It is an essential ingredient in food production, but poor management means bad news downstream. Understanding the way phosphorus behaves in the environment calls for soil and plant biology, and some new soil chemistry.

Design And Analysis Of Clustered, Unmatched Resource Selection Studies, Robert Clark, Tanya Strevens

Robert Clark

Studies which measure animals’ positions over time are a vital tool in understanding the process of resource selection by animals. By comparing a sample of locations that are used by animals with a sample of available points, the types of locations that are preferred by animals can be analysed by using logistic regression. Random-effects logistic regression has been proposed to deal with the repeated measurements that are observed for each animal, but we find that this is not feasible in studies where the sample of available points cannot readily be matched to specific animals. Instead, we investigate the use of …

Sampling Of Subpopulations In Two-Stage Surveys, Robert Clark

Robert Clark

Many health and other surveys aim to produce statistics on small subpopulations, such as specific ethnic groups or the indigenous population of a country. In most countries, there is no reliable sampling frame of the subpopulations of interest, hence it is necessary to sample from the general population, which can be very expensive. A range of issues and strategies for sampling rare subpopulations is reviewed. The most common approaches in practice are the use of a large screening sample, and disproportionate sampling by strata. Optimal sample designs have been derived for the case of one-stage sampling, but most household interview …

Sampling For Subpopulations In Household Surveys With Application To Maori And Pacific Sampling, Robert Clark, Michael Doherty, Angela Forbes, Robert Templeton

Robert Clark

Many NZ national household surveys have a requirement to produce statistics with adequate precision both for the whole of NZ and for important subpopulations, particularly the Maori and Pacific populations. General population surveys which make no special provision for these groups would generally not achieve sufficient precision for Maori and Pacific estimates when these are of particular interest. Kalton and Anderson (1986) described a range of strategies for sampling subpopulations, where the aim is only to produce statistics about the subpopulation and not national statistics. The purpose of this Official Statistics Research fund project is to extend the methods of …

Apolipoprotein J And Leptin Levels In Patients With Coronary Heart Disease, Mark Wilson, Dimitri Mikhailidis, Maria Poulakou, Christos Tsigris, Despina Perrea, Kosmas Paraskevas, Dimitrios Iliopoulos

Mark R Wilson

No abstract provided.

Photoelectron-Photofragment Coincidence Studies Of No-_X Clusters (X = H2o, Cd4), Berwyck Poad, Christopher Johnson, Robert Continetti

Berwyck L. J. Poad

The dissociative photodetachment of NO -(H₂O)and NO -(CD₄) anion clusters was studied at 775 nm (1.60 eV) using photoelectron-photofragment coincidence spectroscopy. The correlation between the photoelectron and photodetached neutral spectra indicates vibrational excitation in the recoiling NO neutral fragments from NO-(H₂O), with a progression consistent with vibrational excitation up to v(NO) = 3 in the products. The correlation remains when D₂O is substituted for H₂O, implying the NO vibrational mode plays a role in the dissociation coordinate of the complex. In contrast, no correlation was observed between photoelectron kinetic …

Ozone-Induced Dissociation On A Modified Tandem Linear Ion-Trap: Observations Of Different Reactivity For Isomeric Lipids, Berwyck Poad, Huong Pham, Michael Thomas, Jessica Hughes, J Campbell, Todd Mitchell, Stephen Blanksby

Berwyck L. J. Poad

Ozone-induced dissociation (OzID) exploits the gas-phase reaction between mass-selected lipid ions and ozone vapor to determine the position(s) of unsaturation. In this contribution, we describe the modification of a tandem linear ion-trap mass spectrometer specifically for OzID analyses wherein ozone vapor is supplied to the collision cell. This instrumental configuration provides spatial separation between mass-selection, the ozonolysis reaction, and mass-analysis steps in the OzID process and thus delivers significant enhancements in speed and sensitivity (ca. 30-fold). These improvements allow spectra revealing the double-bond position(s) within unsaturated lipids to be acquired within 1 s: significantly enhancing the utility of OzID in …

Infrared Spectra Of Mass-Selected Al+_(Ch4)Nn=1-6clusters, B Poad, C Thompson, E Bieske

Berwyck L. J. Poad

Infrared spectra are recorded for Al⁺–(CH₄)_n n = 1–6 clusters in the CH stretch region (2800–3100 cm⁻¹). The spectra, which are obtained by monitoring photofragmentation in a tandem mass spectrometer, are dominated by a single, narrow band corresponding to the totally symmetric C–H stretching mode of the CH₄ subunits (rendered infrared active through the interaction with the Al⁺ cation). This band shifts progressively to higher wavenumber as the clusters becomes larger, concomitant with a weakening of the intermolecular Al⁺⋯CH₄ bonds. Supporting ab initio calculations for the n = …

Mixing Laser Spectroscopy And Mass Spectrometry- Infrared Spectra Of Metal Cation- Hydrogen Complexes, Vikoras Dryza, Berwyck Poad, Evan Bieske

Berwyck L. J. Poad

We describe recent experiments in which mass spectrometry and laser spectroscopy are combined to characterize Li(+)-H(2), Na(+)-H(2), B(+)-H(2), and Al(+)-H(2) complexes in the gas-phase. The infrared spectra, which feature full resolution of rotational sub-structure, are recorded by monitoring M(+) photo fragments as the infrared wavelength is scanned. The spectra deliver detailed information on the way in which a hydrogen molecule is attached to a metal cation including the intermolecular separation, the force constant for the intermolecular bond and the H-H stretching frequency. The complexes all possess T-shaped equilibrium geometries and display a clear correlation between the length and force constant …

Attaching Molecular Hydrogen To Metal Cations: Perspectives From Gas-Phase Infrared Spectroscopy, Viktoras Dryza, Berwyck Poad, Evan Bieske

Berwyck L. J. Poad

In this perspective article we describe recent infrared spectroscopic investigations of mass-selected M⁺–H₂ and M⁺–D₂ complexes in the gas-phase, with targets that include Li⁺–H₂, B⁺–H₂, Na⁺–H₂, Mg⁺–H₂, Al⁺–H₂, Cr⁺–D₂, Mn⁺–H₂, Zn⁺–D₂ and Ag⁺–H₂. Interactions between molecular hydrogen and metal cations play a key role in several contexts, including in the storage of molecular hydrogen in zeolites, metal–organic frameworks, and …

Infrared Spectra Of Cl-_(C6h6)Mm=1, 2, Christopher Thompson, Berwyck Poad, Corinna Emmeluth, Evan Bieske

Berwyck L. J. Poad

The Cl^--(C₆H₆)Ar_n n = 0,1,2 and Cl^--(C₆H₆)₂ complexes are investigated using photodissociation infrared spectroscopy in the CH stretch region and through ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that Cl^--C₆H₆ possesses a planar structure in which the benzene molecule is attached to the Cl^- anion by a double hydrogen bond. The calculations predict that Cl (C₆H₆)₂ has a C₂ symmetry structure in which the two face-to-face benzene molecules are attached to …

A Critical Evaluation Of Retained Acidity (Ar) Estimating Methods In Acid Base Account (Aba) Approach For Acid Sulfate Soils (Ass), Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

No abstract provided.

Understanding The Behaviour Of Schwertmannite And Jarosite In Acid Sulfate Soils, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

No abstract provided.

Readily Available Acidity In Schwertmannite, Chamindra Vithana, Leigh Sullivan, Richard Bush, Edward Burton

Associate Professor Edward D Burton

Schwertmannite and jarosite are considered as less soluble ironhydroxy sulfate minerals which are present in highly acidic environments (pH < 3). These minerals release acidity in the long run as they weather by hydrolysis [1]. However, 1M KCl extraction of soil samples (Clarence and Quartz) spiked with those two minerals showed that schwertmannite has some acidity that may be readily available.

Genesee River Watershed Project. Volume 1.Water Quality Analysis Of The Genesee River Watershed: Nutrient Concentration And Loading, Identification Of Point And Nonpoint Sources Of Pollution, Total Maximum Daily Load, And An Assessment Of Management Practices Using The Soil Water Assessment Tool (Swat) Model. A Report To The Usda., Joseph Makarewicz, Theodore Lewis, Blake Snyder, Mellissa Winslow, Dale Pettenski, Evan Rea, Lindsay Dressel, William Smith

Joseph C Makarewicz

The Genesee River Project, conducted from August 2010 to August 2013, provides a detailed picture of sediment and phosphorus concentrations (e.g., weekly water chemistry sampling), nutrient loading, allocation and identification of phosphorus sources, and the effectiveness of management practices on the four major Genesee River tributaries (Canaseraga, Honeoye, Black, and Oatka Creeks), the Upper Genesee River, and the lower Genesee River. With 60% of the P load (412,505 kg P/yr) from the Genesee River to Lake Ontario being of anthropogenic origin, a managed reduction in P lost from the Genesee watershed is apparent. Models using the Soil and Water Assessment …