Showing papers by "University of Wollongong published in 1996"
TL;DR: Anabranching rivers as mentioned in this paper consist of multiple channels separated by vegetated semi-permanent alluvial islands excised from existing floodplain or formed by within-channel or deltaic accretion.
Abstract: Anabranching rivers consist of multiple channels separated by vegetated semi-permanent alluvial islands excised from existing floodplain or formed by within-channel or deltaic accretion. These rivers occupy a wide range of environments from low to high energy, however, their existence has never been adequately explained. They occur concurrently with other types of channel pattern, although specific requirements include a flood-dominated flow regime and banks that are resistant to erosion, with some systems characterized by mechanisms to block or constrict channels, thereby triggering avulsion. The fundamental advantage of an anabranching river is that, by constructing a semi-permanent system of multiple channels, it can concentrate stream flow and maximize bed-sediment transport (work per unit area of the bed) under conditions where there is little or no opportunity to increase gradient. On the basis of stream energy, sediment size and morphological characteristics, six types of anabranching river are recognized; types 1–3 are lower energy and types 4–6 are higher energy systems. Type 1 are cohesive sediment rivers (commonly termed anastomosing) with low w/d ratio channels that exhibit little or no lateral migration. They are divisible into three subtypes based on vegetative and sedimentary environment. Type 2 are sand-dominated, island-forming rivers, and type 3 are mixed-load laterally active meandering rivers. Type 4 are sand-dominated, ridge-forming rivers characterized by long, parallel, channel-dividing ridges. Type 5 are gravel-dominated, laterally active systems that interface between meandering and braiding in mountainous regions. Type 6 are gravel-dominated, stable systems that occur as non-migrating channels in small, relatively steep basins. Anabranching rivers represent a relatively uncommon but widespread and distinctive group that, because of particular sedimentary, energy-gradient and other hydraulic conditions, operate most effectively as a system of multiple channels separated by vegetated floodplain islands or alluvial ridges.
630 citations
TL;DR: It was really not until the 1980 s that the development of acceptable techniques for the measurement of insulin action in vivo allowed the relationship between dietary fat intake and insulin action to be accurately assessed.
Abstract: The history of research into the relationship between dietary fat intake and impaired insulin action has its origin in the work of Himsworth approximately 60 years ago [1, 2]. In a series of pioneering studies using crude indices of insulin action and limited subject numbers (only one in an often quoted paper!), Himsworth linked high levels of fat intake with insulin resistance, and conversely, improved insulin action with predominantly carbohydrate diet. However, the link was tenuous and really apparent only at the extreme ends of the dietary spectrum (<20 or > 80 % of calories as fat). These studies, flawed as they were, influenced the field enormously in the absence of any significant work in the area for a remarkable period of time. The conclusions reached by Himsworth were reinforced to some extent by misuse of glucose tolerance data that showed deteriorations following periods on diets extremely low in carbohydrate (< 50 g/day) and improvement on liquid formula diets providing a remarkably high percentage (75-85 %) of calories from carbohydrate [3-5]. It was really not until the 1980 s that the development of acceptable techniques for the measurement of insulin action in vivo allowed the relationship between dietary fat intake and insulin action to be accurately assessed. These studies have essentially been confined to investigations in rodents and humans.
356 citations
TL;DR: Direct evidence of in vivo oxidant injury in CEC from inflamed mucosa of IBD patients is provided and supports the exploration of compounds with antioxidant activity as new therapies for IBD.
Abstract: Evidence of in vivo oxidant-induced injury in inflammatory bowel disease (IBD) is largely indirect. Colon epithelial crypt cells (CEC) from paired specimens of histologically normal and inflamed bowel from IBD patients with active disease were examined for altered protein thiol redox status as an indicator of oxidative damage. When CEC preparations from 22 IBD patients were labeled with the reduced-thiol-specific probe [14C]-iodoacetamide (IAM), there was decreased labeling of a number of proteins indicating oxidation of thiol groups in CEC from inflamed mucosa compared to paired normal mucosa, especially the loss of thiol labeling of a 37-kD protein which was almost completely lost. The loss of reduced protein thiol status for the 37-kD band was paralleled by loss of epithelial cell glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) enzyme activity, an enzyme known to contain an essential reduced cysteine (Cys149) at the active site. The identity of the 37-kD protein as GADPH monomer was confirmed by NH2-terminal amino acid sequence analysis. To examine whether this type of in vivo injury could be attributed to biologically relevant oxidants produced by inflammatory cells, CEC prepared from normal mucosa were exposed to H2O2, OCl-, nitric oxide (NO), and a model chloramine molecule chloramine T (ChT) in vitro. Dose-dependent loss of IAM labeling and GAPDH enzyme activity was observed. The efficacy (IC50) against IAM labeling was OCl- >> ChT > H2O2 > NO (52 +/- 3, 250 +/- 17, 420 +/- 12, 779 +/- 120 microM oxidant) and OCl- >> ChT > NO > H2O2 (89 +/- 17, 256 +/- 11, 407 +/- 105, 457 +/- 75 microM oxidant), respectively, for GAPDH enzyme activity. This study provides direct evidence of in vivo oxidant injury in CEC from inflamed mucosa of IBD patients. Oxidation and inhibition of essential protein function by inflammatory cells is a potential mechanism of tissue injury that may contribute to the pathogenesis of the disease and supports the exploration of compounds with antioxidant activity as new therapies for IBD.
345 citations
TL;DR: In this article, a method for the quantitative analysis of gas-phase infrared spectra is described in which calibration spectra are calculated from a database of absorption line parameters rather than measured in a real spectrometer.
Abstract: A method for the quantitative analysis of gas-phase infrared spectra is described in which calibration spectra are calculated from a database of absorption line parameters rather than measured in a real spectrometer. The synthetic calibration spectra are computed with the use of the program MALT (Multiple Atmospheric Layer Transmission), including environmental (pressure, temperature, pathlength, etc.) and instrumental (resolution, line shape, wavenumber shift) effects in the calculation, so that the calculated spectra closely approximate real measured spectra. The synthetic calibration spectra are then used in quantitative analysis as if they were real spectra. In conventional laboratory studies, the method circumvents the need for time-consuming collection of large sets of laboratory calibration spectra often required when many absorbing gases must be analyzed. It is particularly useful in long open-path and solar FT-IR spectroscopy when no sample cell is available for recording calibration spectra. Examples are presented from conventional laboratory spectra in a closed-cell, open-path FT-IR spectra used to determine trace gas fluxes in an open field, and solar absorption spectroscopy using ground-based FT-IR spectrometers.
336 citations
TL;DR: A sliding Goertzel algorithm to accurately estimate the Fourier coefficients of multifrequency (MF) sinusoidal signals buried in noise is presented, based on second-order digital resonators that are tuned at the desired frequencies.
312 citations
TL;DR: The results showed that the ability to stabilize the pelvis against resistance is decreased during pregnancy and at least 8 weeks postbirth, abdominal muscle exercises should be chosen with care.
Abstract: Background and Purpose. The purpose of this study was to investigate the abdominal muscle structural adaptations and functional capabilities during pregnancy and the postbirth period. Subjects. Six primigravid subjects, aged 28 to 33 years, participated in nine test sessions from 14 weeks of gestation to 8 weeks postbirth. Methods. At each test session, three-dimensional photography of abdominal skin markers was used to determine the gross morphology of a representative abdominal muscle, the rectus abdominis muscle. The functional capability of the abdominal muscle group was assessed on the ability of the muscle group to stabilize the pelvis against resistance. Results. Increases were found in rectus abdominis muscle separation width, length, and angles of insertion as pregnancy progressed. Reversal in rectus abdominis muscle separation was found by 4 weeks postbirth. The ability to stabilize the pelvis against resistance was shown to be decreased as pregnancy progressed and remained compromised postbirth. Decrements in abdominal muscle function paralleled in time the structural adaptations, as pregnancy progressed. Continued functional deficits were found in parallel with incomplete resolution of structural adaptations postbirth. Conclusion and Discussion. Abdominal muscle function is affected by structural adaptations that occur during pregnancy. Because our results showed that the ability to stabilize the pelvis against resistance is decreased during pregnancy and at least 8 weeks postbirth, abdominal muscle exercises should be chosen with care.
200 citations
TL;DR: Based on the similarity analysis between the spherical and nonspherical particle packings, a mathematical model, modified from the previous linear packing model for spherical particles, is proposed for predicting the porosity of non-pregnant particle mixtures.
Abstract: Based on the similarity analysis between the spherical and nonspherical particle packings, a mathematical model, modified from the previous linear packing model for spherical particles, is proposed for predicting the porosity of nonspherical particle mixtures. The background for this development is discussed in detail. The applicability of the proposed model is validated by the good agreement between the measured and calculated results for various packing systems including binary, ternary, and multicomponent packing of spherical and/or nonspherical particles.
198 citations
TL;DR: It is shown that some widely accepted criteria for cryptographic functions, including the strict avalanche criterion (SAC) and the propagation criterion, have various limitations in capturing properties of vital importance to cryptographic algorithms, and a new criterion called GAC is proposed to measure the global avalanche characteristics of cryptographic functions.
Abstract: We show that some widely accepted criteria for cryptographic functions, including the strict avalanche criterion (SAC) and the propagation criterion, have various limitations in capturing properties of vital importance to cryptographic algorithms, and propose a new criterion called GAC to measure the global avalanche characteristics of cryptographic functions. We also introduce two indicators related to the new criterion, one forecasts the sum-of-squares while the other the absolute avalanche characteristics of a function. Lower and upper bounds on the two indicators are derived, and two methods are presented to construct cryptographic functions that achieve nearly optimal global avalanche characteristics.
179 citations
TL;DR: Age-related changes in the morphology of the ERP elicited by standard tones (especially the N2 and P2 components), as well as concurrent morphological changes in standard and target tones, are discussed.
175 citations
TL;DR: The range of evidence in humans and experimental animals demonstrating close associations between insulin action and two major aspects of muscle morphology: fatty acid composition of the major structural lipid (phospholipid) in muscle cell membranes and relative proportions of major muscle fiber types is reviewed.
Abstract: Skeletal muscle plays a major role in insulin-stimulated glucose disposal. This paper reviews the range of evidence in humans and experimental animals demonstrating close associations between insulin action and two major aspects of muscle morphology: fatty acid composition of the major structural lipid (phospholipid) in muscle cell membranes and relative proportions of major muscle fiber types. Work in vitro and in vivo in both rats and humans has shown that incorporation of more unsaturated fatty acids into muscle membrane phospholipid is associated with improved insulin action. As the corollary, a higher proportion of saturated fats is linked to impairment of insulin action (insulin resistance). Studies in vitro suggest a causal relationship. Among polyunsaturated fatty acids (PUFA) there is some, but not conclusive, evidence that omega-3 (n-3) PUFA may play a particular role in improving insulin action; certainly a high n-6/n-3 ratio appears deleterious. In relation to fiber type, the more highly oxidative, insulin-sensitive type 1 and type 2a fibers have a higher percentage of unsaturated fatty acids, particularly n-3, in their membrane phospholipid, compared to the insulin-resistant, glycolytic, type 2b fibers. These variables, however, can be separated and may act in synergy to modulate insulin action. It remains to establish whether lifestyle (e.g., dietary fatty acid profile and physical activity), genetic predisposition, or a combination are the prime determinants of muscle morphology (particularly membrane lipid profile) and hence insulin action.
170 citations
TL;DR: In this paper, a finite strip model for elastic local buckling is used to study the behavior of steel plates in composite steel-concrete members, and the accuracy of the numerical method is demonstrated by a comparison with solutions in the literature.
TL;DR: In this paper, measurements of the 13C and 14C signatures of particulate organic carbon from surface soils of C3 biomes from a global distribution of low-altitude, non-water-stressed locations are reported.
Abstract: ATTEMPTS to model the global carbon cycle, and anthropogenic modifications to carbon flow between the atmospheric, oceanic and terrestrial carbon reservoirs, commonly rely on values assumed for the 13C/12C ratio and 'bomb-spike' 14C signature of carbon in each reservoir1,2. A large proportion of the carbon in the terrestrial biosphere resides in the soil organic carbon (SOC) pool3, most of which is derived from plants that assimilate carbon via the C3 photosynthetic pathway4. Here we report measurements of the 13C and 14C signatures of particulate organic carbon from surface soils of C3 biomes from a global distribution of low-altitude, non-water-stressed locations. We find that there is currently a latitudinal gradient in the signature, with low-latitude soils being relatively depleted in 13C. The 14C signatures indicate that today's gradient is due to a latitudinal gradient in the residence time of the soil organic carbon, coupled with anthropogenic modifications to the 13C/12C ratio of atmospheric CO2 (for example by fossil-fuel burning5). The long residence times (tens of years) of particulate organic carbon from high-latitude soils provide empirical evidence that if fluxes of carbon from vegetation to the soil increase, these soils have the capacity to act as a carbon sink on decadal timescales.
TL;DR: The distribution of the leptin receptor in the brain of C57 mice was investigated using a non-radioactive in situ hybridization method and the localization of leptin receptor-containing neurones in the present study indicates the possibility that the leptin receptors are expressed on neuropeptide Y-containing neurons.
Abstract: The distribution of the leptin receptor in the brain of C57 mice was investigated using a non-radioactive in situ hybridization method. Leptin receptor mRNA expression was highest in the arcuate nucleus and median eminence of the hypothalamus, but it was also abundant in hippocampus, primarily in the dentate gyrus and CA1, and was detected at low levels in piriform cortex and the medial margin of the medial habenular nucleus. The localization of leptin receptor-containing neurones in the present study indicates the possibility that the leptin receptor is expressed on neuropeptide Y-containing neurones.
TL;DR: Factors such as its small size, immediate retrieval of results, high accuracy attainable from low applied doses, and as the MOSFET records its dose history make it a suitable in vivo dosimeter where surface and skin doses need to be determined.
Abstract: Radiotherapy x-ray and electron beam surface doses are accurately measurable by use of a MOS-FET detector system. The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is approximately 200-microns in diameter and consists of a 0.5-microns Al electrode on top of a 1-microns SiO2 and 300-microns Si substrate. Results for % surface dose were within +/- 2% compared to the Attix chamber and within +/- 3% of TLD extrapolation results for normally incident beams. Detectors were compared using different energies, field size, and beam modifying devices such as block trays and wedges. Percentage surface dose for 10 x 10-cm and 40 x 40-cm field size for 6-MV x rays at 100-cm SSD using the MOSFET were 16% and 42% of maximum, respectively. Factors such as its small size, immediate retrieval of results, high accuracy attainable from low applied doses, and as the MOSFET records its dose history make it a suitable in vivo dosimeter where surface and skin doses need to be determined. This can be achieved within part of the first fraction of dose (i.e., only 10 cGy is required.)
TL;DR: The results of two studies into the "Big Five" personality factors associated with interpersonal violence and vandalism/theft are reported in this paper, and the results are discussed with reference to previous research into the personality correlates to delinquency.
TL;DR: In this paper, the ages of four major periods of palaeochannel activity have been identified on the Murrumbidgee sector of the Riverine Plain of southeastern Australia.
Abstract: Four major periods of palaeochannel activity have been identified on the Murrumbidgee sector of the Riverine Plain of southeastern Australia. On the basis of stratigraphic information the channels reveal a picture of changing flow conditions during the last full glacial cycle. The ages of the periods were determined from nearly 40 thermoluminescence dates on surficial fluvial and aeolian sediments. These are named the Coleambally phase, which occurred from 105 to 80 ka (the mid- to latter part of Oxygen Isotope Stage 5), the Kerarbury phase from 55 to 35 ka (Stage 3), the Gum Creek phase from 35 to 25 ka (late Stage 3 to early Stage 2) and the Yanco phase from 20 to 13 ka (late Stage 2). The present flow regime was established by about 12 ka (Stage 1). The first two phases correlate with episodes of enhanced fluvial activity in northern and central Australia and with reduced dust activity globally. The phases in Stage 2 appear to be associated with seasonal snow melt and increased peak flows in periods flanking the Last Glacial Maximum. Source-bordering aeolian dunes associated with the Coleambally, Kerarbury and Yanco phases were found, however, the TL dates show that some have undergone aeolian reworking. Thermoluminescence dating and fluvial stratigraphy have revealed a detailed picture of Late Quaternary climate and flow regime changes that has the potential to extend to identified deposits stratigraphically older than those described here.
TL;DR: It is concluded that changing the polarity of the C-terminal extension of αA-crystallin by insertion of a highly hydrophobic residue can seriously disturb structural and functional integrity.
TL;DR: Those women who had a recurrence of their GDM were older, more parous, and also had an increase in weight between the pregnancies, which was associated with a higher glucose level, insulin use, or fetal birth weight in the index pregnancy.
Abstract: OBJECTIVE To define the recurrence rate of gestational diabetes mellitus (GDM) in a subsequent pregnancy and to determine what factors could be predictive. RESEARCH DESIGN AND METHODS The subjects of the index pregnancy were 480 personally cared for women with GDM. One hundred women had had a subsequent pregnancy and had been tested for GDM. RESULTS The recurrence rate of GDM was 35% (95% CI, 25.5–44.5). An increase in weight between the two pregnancies and a higher maternal age and parity were risk associates for a recurrence. A recurrence of GDM was not associated with a higher glucose level, insulin use, or fetal birth weight in the index pregnancy. CONCLUSIONS GDM occurs in only one-third of subsequent pregnancies. Those women who had a recurrence of their GDM were older, more parous, and also had an increase in weight between the pregnancies.
TL;DR: Rehabilitation units are not functioning as learning environments and subjects in both units spent more than 70% of their day in activities largely unrelated to physical outcome and less than 20% of the day in Activities that could potentially contribute to their recovery.
TL;DR: The nature and date of the human colonization of Australia remains a key issue in prehistory at the world scale, for a sufficiently early presence there indicates either Homo sapiens sapiens arriving precociously in a place remote from a supposed African origin, or a greater competence in sea-crossing than has been expected of archaic humans.
Abstract: The nature and date of the human colonization of Australia remains a key issue in prehistory at the world scale, for a sufficiently early presence there indicates either Homo sapiens sapiens arriving precociously in a place remote from a supposed African origin, or a greater competence in sea-crossing than has been expected of archaic humans. Stratigraphic integrity, the new science of luminescent dating and the recognition of worked stone and of rock-engraving are immediate issues in this report from far northwestern Australia.
TL;DR: In this article, the authors review some of the recent developments in the mathematical modelling of microwave heating, including models that consider in isolation the heat equation with a nonlinear source term, in which case the electric-field amplitude is assumed constant, models involving the coupling between the electric field amplitude and temperature, and also models that control the process of thermal runaway.
TL;DR: Gambusia holbrooki, the “Mosquito Fish” introduced to Australian waterways from North America to control mosquito larvae, is widely distributed and abundant in both disturbed and undisturbed aquatic environments.
Abstract: Gambusia holbrooki, the “Mosquito Fish” introduced to Australian waterways from North America to control mosquito larvae, is widely distributed and abundant in both disturbed and undisturbed aquatic environments. Because it has become established in areas where Litoria aurea was once abundant, there is some suspicion that G. holbrooki's non-specific predatory behaviour may be instrumental in the decline of L. aurea.Laboratory and field experiments were conducted to assess the impact of G. holbrooki predation on L. aurea tadpole survivorship. Laboratory trials involved placing 30 L. aurea tadpoles per 46-litre aquarium in each of the following four treatments: control treatments (two aquaria with just tadpoles and two aquaria with tadpoles and the pondweed, Egeria densa) and two predator treatments (two aquaria with fish and tadpoles and two aquaria with tadpoles, fish and pondweed). A daily census of the tadpoles was taken over four days. Based on ANOVA of six aquaria for each treatment, G. holbrooki sign...
TL;DR: It is observed that age-dependent silencing is most severe in high copy number animals, and it is speculated that it reflects a general mechanism of epigenetic regulation.
Abstract: Variegation of transgene expression, a heterocellular or mosaic pattern of expression seen in all mice in a given transgenic line, is a frequently observed but unexplained phenomenon. We have encountered variegation with globin transgenes; when lacZ expression is driven by globin control elements a proportion of erythrocytes express β-galactosidase (β-gal), while the remaining erythrocytes express none. The percentage of expressing cells is constant within each line (at any particular developmental stage), but varies between lines. Such variation may account for much of the line-to-line variability which has been reported in the expression of a transgene construct. We have now extended these observations by studying expression of several globin/lacZ transgenes with increasing age. Expression of β-gal is variegated in all lines in adult mice, including those made with a β-globin promoter and locus control region driving lacZ. The extent of variegation differs widely between lines, but in all lines there is a marked decline in the number of erythrocytes expressing β-gal with increasing age. Progression of silencing continues long past the point at which globin switching is complete, suggesting that it is not related to this process. We observe that age-dependent silencing is most severe in high copy number animals. Increasing variegation of transgene expression with ageing of mice is likely to complicate interpretation of the developmental regulation of transgenes. We speculate that it reflects a general mechanism of epigenetic regulation.
TL;DR: A novel flow injection amperometric urea biosensor, based on the incorporation of urease into a conductive polypyrrole film, confirms that the biocatalytic reaction product contained either ammonia or ammonium ions.
TL;DR: Although reproductive development appears to be resistant to naturally relevant temperature extremes in both sexes, low environmental temperature impaired preparations for migration in females but not males.
TL;DR: It is demonstrated that in rats, the fatty acid profile of skeletal muscle phospholipids is strongly influenced by dietary changes, with most effects being reversible after short periods of adequate dietary intake.
Abstract: Changes in dietary fatty acid composition alter phospholipid fatty acid composition in a variety of tissues, but little attention has been paid to skeletal muscle. In this study, rats were fed for 9 wk one of three isoenergetic diets: an essential fatty acid-deficient diet, a diet high in (n-6) fatty acids, and a diet enriched with (n-3) fatty acids. Some rats from each group were fed a nonpurified diet for a further 2 or 6 wk. Neither body mass nor food consumption varied among the dietary groups at any stage. Analyses of total phospholipids in soleus (a "slow" twitch muscle) and extensor digitorum longus (a "fast" twitch muscle) revealed that after 9 wk of test diet consumption, muscle phospholipids from rats fed the essential fatty acid-deficient diet were deficient in essential polyunsaturated fatty acids (triene:tetraene ratio >0.5), whereas the polyunsaturated fatty acids in muscle phospholipids from rats fed the high (n-6) fatty acid and high (n-3) fatty acid diets reflected the composition of their respective diets. Nevertheless, phospholipid fatty acid compositions of seemed to be selectively dynamic. After recovery, although the phospholipid fatty acid compositions of all groups were similar, they all contained a much higher proportion of (n-3) fatty acid than provided in the diets. Overall, these results demonstrate that in rats, the fatty acid profile of skeletal muscle phospholipids is strongly influenced by dietary changes, with most effects being reversible after short periods of adequate dietary intake.
TL;DR: The use of approach and avoidance coping styles and task-focused and emotion-focused coping strategies in competitive sport was explored, providing support for the transactional model.
Abstract: The use of approach and avoidance coping styles and task-focused and emotion-focused coping strategies in competitive sport was explored. Four hundred twenty-one adolescent males from New South Wales, Australia, who were currently competing in team sports indicated their usual responses to each of 8 acute stressors commonly experienced in sport, using a 128-item inventory. The reliability coefficient (Cronbach's alpha) for each stressor ranged from .81 to .92. Twenty-six of the original 128 items on the inventory were retained, on the basis of factor analysis. Correlations between stressors indicated that coping styles were a function of type of stressor, providing support for the transactional model. Goodness of fit was high (.87). The present results partially support the construct of coping style among adolescent-aged sports competitors.
TL;DR: It is proposed that the ADHD group, relative to controls, utilizes an additional cognitive process when processing task-relevant stimuli that is more frontally distributed and may reflect an attentional compensation mechanism in the ADHDgroup.
Abstract: Auditory event-related potentials (ERPs) were recorded from 10 children diagnosed with attention deficit hyperactivity disorder (ADHD) and 10 age-, sex-, and IQ-matched control children. ERPs were recorded from 17 electrodes during an auditory two-tone discrimination (‘oddball') paradigm. Subjects were instructed to press a hand-held response button to infrequently presented target tones. ERP components elicited to target and non-target stimuli were analyzed for between-group differences. Results indicated that for the children with ADHD relative to control children, an N 2 component to non-target stimuli was larger in the posterior region and smaller in the frontal region. The P 3b component to target stimuli was smaller in the posterior region and larger in the frontal region for the ADHD group compared with the control group. The between-group differences in P 3b scalp distribution are indicative of a between-group difference in the neural generators of P 3b . It is proposed that the ADHD group, relative to controls, utilizes an additional cognitive process when processing task-relevant stimuli. This process is more frontally distributed and may reflect an attentional compensation mechanism in the ADHD group.
TL;DR: In this paper, it is shown that the higher-order solitary-wave collisions are elastic, to the order of approximation of the extended KdV equation, and the higherorder corrections to the phase shifts are found.
Abstract: Soliton interactions for the extended Korteweg-de Vries (KdV) equation are examined. It is shown that the extended KdV equation can be transformed (to its order of approximation) to a higher-order member of the KdV hierarchy of integrable equations. This transformation is used to derive the higher-order, two-soliton solution for the extended KdV equation. Hence it follows that the higher-order solitary-wave collisions are elastic, to the order of approximation of the extended KdV equation. In addition, the higher-order corrections to the phase shifts are found. To examine the exact nature of higher-order, solitary-wave collisions, numerical results for various special cases (including surface waves on shallow water) of the extended KdV equation are presented. The numerical results show evidence of inelastic behaviour well beyond the order of approximation of the extended KdV equation; after collision, a dispersive wavetrain of extremely small amplitude is found behind the smaller, higher-order solitary wave.