Investigation of compounds causing water repellency in the rhizosphere of sandy soils from a wide range of locations.

Although soils are generally considered to wet readily, some are actually water repellent at the surface and in the rhizosphere. This phenomenon occurs at low to moderate moisture contents and has been reported from soils under a range of vegetation types and from many regions around the globe. Water repellency in soils can have serious environmental implications including reduced seed germination and plant growth as well as irrigation efficiency, accelerated soil erosion, and enhanced leaching of agrochemicals through preferential flow. it has been proposed that water repellency is caused by the accumulation of hydrophobic organic compounds released as root exudates, microbial byproducts or from decomposing organic matter, which are deposited on mineral or aggregate surfaces, or are present as interstitial matter, Few studies to date have attempted to isolate and characterize these compounds and their structure is therefore only poorly understood, These studies have generally focussed on only a single soil or a small range of samples, have not included non-repellent soils as a control and have not always been able to demonstrate that the substances isolated are indeed responsible for repellency formation.

This study reports on the first part (extraction procedures) of a research programme addressing these gaps in current knowledge by investigating a wide range of severely repellent and wettable ‘control’ samples from different countries, and by including assessments of extraction efficiency and ability of extracts to cause repellency. Analytical methods include DRIFT (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) of soils and IR (Infrared) analysis of extracts.

Key findings are that (i) soil sample heating after extraction is valuable in assessing the effectiveness of the extraction procedure, (ii) Soxhlet extraction using isopropanol/ ammonia (70/30 v/v) was the most effective method in extracting hydrophobic compounds, while leaving the ability of extracted compounds to induce water repellency virtually unaffected, (iii) wettable control soils also contain hydrophobic substances capable of inducing water repellency, (iv) the amount of organic compounds extracted was poorly related to sample repellency, indicating that compounds responsible for repellency may only represent a small fraction of the extract, (v) differences in extraction efficiency between different samples indicate that the compounds responsible may differ generically and/or in terms of their bonding to minerals, and (vi) the combination of repellency assessments with DRIFT on soils and JR on extracts used with internal standards has considerable potential to allow quantification of CH bearing organic matter in the soil, the efficiency of extraction processes for its removal, and its significance in causing water repellency in soils.

Range extension of the Millewa Skink Hemiergis millewae in the Murray-Sunset National Park, Victoria

This article reports a range extension for the critically endangered Millewa Skink Hemiergis millewae in Victoria. An individual H. millewae was found approximately 85 km east of its former known range in mature mallee vegetation, near the eastern edge of the Murray-Sunset National Park on 27 March 2007. Site characteristics are described, and a list of other reptile species found at the same site is provided. Further research into the habitat associations and distribution of H. millewae is recommended in order to guide the management of this species.

Multifractality and long-range dependence of asset returns: the scaling behavior of the Markov-switching multifractal model with lognormal volatility components

In this paper, we consider daily financial data from various sources (stock market indices, foreign exchange rates and bonds) and analyze their multiscaling properties by estimating the parameters of a Markov-switching multifractal (MSM) model with Lognormal volatility components. In order to see how well estimated models capture the temporal dependency of the empirical data, we estimate and compare (generalized) Hurst exponents for both empirical data and simulated MSM models. In general, the Lognormal MSM models generate "apparent" long memory in good agreement with empirical scaling provided that one uses sufficiently many volatility components. In comparison with a Binomial MSM specification [11], results are almost identical. This suggests that a parsimonious discrete specification is flexible enough and the gain from adopting the continuous Lognormal distribution is very limited.

Optimal range-difference-based localization considering geometrical constraints

This paper proposes a new type of algorithm aimed at finding the traditional maximum-likelihood (TML) estimate of the position of a target given time-difference-of-arrival (TDOA) information, contaminated by noise. The novelty lies in the fact that a performance index, akin to but not identical with that in maximum likelihood (ML), is a minimized subject to a number of constraints, which flow from geometric constraints inherent in the underlying problem. The minimization is in a higher dimensional space than for TML, and has the advantage that the algorithm can be very straightforwardly and systematically initialized. Simulation evidence shows that failure to converge to a solution of the localization problem near the true value is less likely to occur with this new algorithm than with TML. This makes it attractive to use in adverse geometric situations.

Afternoon T : Testosterone level is higher in red than yellow male polychromatic lizards

Recent work on within-species polymorphism across a broad range of taxa has renewed and considerably increased the attention to this classic evolutionary area, notably in lizard species where colors covary with reproductive strategies. We demonstrate elsewhere that red-headed males beat yellow-headed males in staged contests for females in the Australian painted dragon lizard Ctenophorus pictus. This morph difference in behaviour is linked to what appears to be a convention of red dominance in male–male interactions set very early in ontogeny, long before coloration has developed. In the current note, we investigate the relationship between time of day, which is directly linked to vigilance time in territorial males, and plasma levels of testosterone and corticosterone. We show that red males have higher testosterone levels in late afternoon following a day of territory patrolling and a non-significant trend in plasma corticosterone levels that decline with time of day. In conclusion, there are significant differences in testosterone profile between the two color morphs, providing a potential proximate link to the behavioural differences between them.

Forecasting stock index volatility : comparing implied volatility and the intraday high-low price range

The intraday high–low price range offers volatility forecasts similarly efficient to high-quality implied volatility indexes published by the Chicago Board Options Exchange (CBOE) for four stock market indexes: S&P 500, S&P 100, NASDAQ 100, and Dow Jones Industrials. Examination of in-sample and out-of-sample volatility forecasts reveals that neither implied volatility nor intraday high–low range volatility consistently outperforms the other.

True and apparent scaling : the proximity of the Markov-switching multifractal model to long-range dependence

In this paper, we consider daily financial data of a collection of different stock market indices, exchange rates, and interest rates, and we analyze their multi-scaling properties by estimating a simple specification of the Markov-switching multifractal (MSM) model. In order to see how well the estimated model captures the temporal dependence of the data, we estimate and compare the scaling exponents H(q) (for q=1,2) for both empirical data and simulated data of the MSM model. In most cases the multifractal model appears to generate ‘apparent’ long memory in agreement with the empirical scaling laws.

Influence of posture on the range of axial rotation and coupled lateral flexion of the thoracic spine

Objective
This study examines the influence of posture on the range of axial rotation of the thorax and the range and direction of the coupled lateral flexion.

Methods
The ranges of mid thoracic axial rotation and coupled lateral flexion were measured in 52 asymptomatic subjects (aged 18-43 years) using an optical motion analysis system. To examine the influence of posture on primary and coupled motion, we initiated axial rotation from a neutral sitting posture and from end-range thoracic flexion and extension.

Results
There was a significant decrease in the range of thoracic rotation in flexion compared with the neutral and extended postures (P < .001). The mean range of coupled lateral flexion was 8.9% of the axial rotation range in the neutral posture and increased to 14.3% and 23.2% in the extended and flexed postures, respectively. Patterns of coupled motion varied between subjects, but an ipsilateral pattern was more common in the flexed posture, whereas a contralateral pattern was more common in the neutral and extended postures.

Conclusions
The ranges and patterns of coupled motion of the thorax appear to be strongly influenced by the posture from which the movement is initiated. This has important implications in relation to the interpretation of clinical tests of thoracic motion and in consideration of mechanisms of development of thoracic pain disorders.

Range-wide phylogeography of the Little Penguin (Eudyptula minor): evidence of long-distance dispersal

The Little Penguin (Eudyptula minor), a colonial-nesting seabird that is widespread in New Zealand and southern Australia, has high dispersal potential but exhibits regional variation in morphology, coloration, and breeding phenology. We present a distribution-wide survey of mitochondrial DNA variation in the Little Penguin to document phylogeographic relationships and genetic structuring and to test for concordance with intraspecific taxonomy. Phylogeographic structuring was absent among Australian colonies (27 localities, 94 individuals), but the distribution of haplotypes among colonies was significantly nonrandom (ϕST = 0.110, P < 0.01). The Australian individuals exhibited close phylogenetic relationships with a subset of New Zealand birds (4 localities, 22 individuals), whereas the remaining New Zealand birds (20 localities, 106 individuals) were phylogenetically distinct, with ≥7% sequence divergence, and exhibited greater levels of genetic variation and geographic structuring (ϕST = 0.774, P < 0.05). These patterns are consistent with earlier suggestions of an origin in New Zealand followed by recent colonization of Australia and back-dispersal to New Zealand. Extinction and re-establishment processes may have been important factors in the development of genetic structuring across a range of spatiotemporal scales. The genetic data are consistent with suggestions that a single subspecies exists in Australia, but not with the subspecies distributions within New Zealand that have been suggested on the basis of morphology and coloration.

Population structure in the highly fragmented range of Tor douronensis (Cyprinidae) in Sarawak, Malaysia revealed by microsatellite DNA markers

1. Understanding the structure of threatened populations, particularly those that exist in degraded or fragmented habitats is crucial for their effective management and conservation. Recently developed methods of individual-based analysis of genetic data provide an unprecedented opportunity to understand the relationships amongst fragmented populations.

2. In the present study, population structure of an important cyprinid species (Tor douronensis), which is indigenous to Sarawak, Malaysia, is investigated as part of an ongoing conservation effort to restore threatened wild populations of the species. The population structure inferred using data from seven autosomal microsatellite loci was generally consistent with geography and habitat fragmentation.

3. The results indicate that there are two well-defined clusters of T. douronensis in Sarawak, namely the 'northeastern' and the 'southwestern' clusters. In addition, a further subdivision was observed in each of the clusters distributed between river systems. Low levels of gene flow were also observed and migrants between habitat fragments were identified, possibly resulting from human-mediated translocations.

4. Implications of the findings for management and conservation of T. douronensis are discussed.

Modelling and testing of long range battery electric vehicle performance

There are two significant issues facing road transport in the medium to long term: the depletion of cheap oil reserves and the need to reduce carbon emissions. A long term solution for passenger cars could be the introduction of battery electric vehicles (BEVs). However, one of the main problems associated with the current generation of BEVs is their short range relative to conventional internal combustion engine (ICE) cars.

To investigate this issue, a long range battery electric vehicle, the UltraCommuter (UC), was constructed by the University of Waikato in partnership with HybridAuto Ltd. This paper describes the development, modelling and testing of the UC and its performance in the 2007 World Solar Challenge.