Locoregional hyperthermia of deep-seated tumours applied with capacitive and radiative systems. A simulation study

Background: Locoregional hyperthermia is applied to deep-seated tumours in the pelvic region. Two very different heating techniques are often applied: capacitive and radiative heating. In this paper, numerical simulations are applied to compare the performance of both techniques in heating of deep-seated tumours. Methods: Phantom simulations were performed for small (30 × 20 × 50 cm 3 ) and large (45 × 30 × 50 cm 3 ), homogeneous fatless and inhomogeneous fat-muscle, tissue-equivalent phantoms with a central or eccentric target region. Radiative heating was simulated with the 70 MHz AMC-4 system and capacitive heating was simulated at 13.56 MHz. Simulations were performed for small fatless, small (i.e. fat layer typically 3 cm) patients with cervix, prostate, bladder and rectum cancer. Temperature distributions were simulated using constant hyperthermic-level perfusion values with tissue constraints of 44 °C and compared for both heating techniques. Results: For the small homogeneous phantom, similar target heating was predicted with radiative and capacitive heating. For the large homogeneous phantom, most effective target heating was predicted with capacitive heating. For inhomogeneous phantoms, hot spots in the fat layer limit adequate capacitive heating, and simulated target temperatures with radiative heating were 2–4 °C higher. Patient simulations predicted therapeutic target temperatures with capacitive heating for fatless patients, but radiative heating was more robust for all tumour sites and patient sizes, yielding target temperatures 1–3 °C higher than those predicted for capacitive heating. Conclusion: Generally, radiative locoregional heating yields more favourable simulated temperature distributions for deep-seated pelvic tumours, compared with capacitive heating. Therapeutic temperatures are predicted for capacitive heating in patients with (almost) no fat

Detection of hearing losses (HL) via transient-evoked otoacoustic emissions: towards an automatic classification

Transiently evoked otoacoustic emissions (TEOAEs) are routinely used in the hearing assessment of the auditory periphery. The major contribution of TEOAEs is the early detection of hearing losses in neonates, children, and adults. The evaluation of TEOAE responses by specific signal decomposition techniques offers numerous advantages for current and future research. One methodology, based on recurrence quantification analysis (RQA), can identify adult subjects presenting sensorineural hearing impairments. In two previous papers, the RQA-based approach was successfully applied in identifying and classifying cases presenting noise and age related hearing losses. The current work investigates further two aspects of the previously proposed RQA-based analysis for hearing loss detection: (i) the reliability of a Training set built from different numbers of ears with normal hearing, and (ii) the threshold set of values of the key hearing loss detecting parameter RAD2D.Results:The Training set built from 158 healthy ears was found to be quite reliable and a similar but slightly minor performance was observed for the training set of 118 normal subjects, used in the past; the proposed ROC-curve method, optimizing the values of RAD2D, shows improved sensibility and specificity in one class discrimination.Conclusions.A complete and simplified procedure, based on the combined use of the traditional TEOAE reproducibility value and on values from the RQA-based RAD2D parameter, is proposed as an improved automatic classifier, in terms of sensitivity and specificity, for different types of hearing losses

Who participates in conservation incentive programs? Absentee and group landholders are in the mix

Voluntary incentive programs are widely used to generate conservation actions on private land. Although there is a growing body of research about factors that influence landholder participation in incentive programs, studies generally conceptualise landholders in agricultural landscapes as owner-occupier, farming individuals or families. Few studies have considered participation by absentee landholders and fewer still have recognised group landholders (e.g. non-government organisations or community groups) as potential incentive program participants. We examined participation in a conservation stewardship tender (reverse auction) in South Australia to identify the diversity within participants, and particularly to evaluate the extent of participation by absentee landholders and groups. A diverse set of landholders participated, where nearly a quarter of participants were absentee landholders, and a small component were groups. Although small in number, groups were shown to be important because they were likely to offer larger land areas in the stewardship tender. With very little known about how absentee and group landholders may differ from their counterparts, further research is recommended to inform incentive program design. We recommend that incentive programs consider landholder diversity in order to achieve effective conservation in agricultural landscapes.Anthelia J. Bond, Patrick J. O’Connor, Timothy R. Cavagnar

Detection of age-related hearing losses (Arhl) via transient-evoked otoacoustic emissions

Purpose: The objective of the study was to identify subjects presenting hearing deficits, specifically age-related hearing losses (ARHL), via objective assessment methodologies. Materials and Methods: Initially, 259 subjects (165 men, 94 women) were enrolled in the study. After the application of inclusion criteria, the final number was reduced to 88 subjects (49.8 ± 19.1 ys) subdivided into 64 normal and 83 ARHL cases. The subjects were assessed with traditional audiometry tests and with transiently evoked otoacoustic emissions (TEOAEs). Since each ear has its own acoustic signature, the TEOAE analyses were conducted in terms of ears and not subjects. The TEOAE data were processed by traditional and recurrence quantification analyses, leading to the estimation of the WWR (whole waveform reproducibility) and the new RAD2D (2-dimensional radius) parameters. A plot of WWR vs RAD2D was used to optimize the classification of the cases presenting ARHL. Results: By using a WWR value of 70% as a classifier, the sensitivity of TEOAEs was estimated as 75.9% and the specificity as 89.1%. By using the RAD2D parameter (with a cutoff value of 1.78), a sensitivity value of 80.7% and a specificity value of 71.9% were obtained. When both parameters were used, a sensitivity value of 85.5% and a specificity value of 92.2% were estimated. In the latter classification paradigm, the number of false negatives decreased from 20 to 12 out of 83 ears (14%). Conclusion: In adult hearing screening assessments, the proposed method optimizes the identification of subjects with a hearing impairment correlated to the presence of age-related hearing loss

Challenges in applying scientific evidence to width recommendations for riparian management in agricultural Australia

Intact riparian zones maintain aquatic-terrestrial ecosystem function and ultimately, waterway health. Effective riparian management is a major step towards improving the condition of waterways and usually involves the creation of a 'buffer' by fencing off the stream and planting vegetation. Determination of buffer widths often reflects logistical constraints (e.g. private land ownership, existing infrastructure) of riparian and adjacent areas, rather than relying on rigorous science. We used published information to support riparian width recommendations for waterways in agricultural Victoria, Australia. We focused on different ecological management objectives (e.g. nutrient reduction or erosion control) and scrutinised the applicability of data across different environmental contexts (e.g. adjacent land use or geomorphology). Not surprisingly, the evidence supported variable 'effective' riparian widths, depending on the objective and environmental context. We used this information to develop a framework for determining riparian buffer widths to meet a variety of ecological objectives in south-east Australia. Widths for reducing nutrient inputs to waterways were most strongly supported with quantitative evidence and varied between 20 and 38 m depending on environmental context. The environmental context was inconsistently reported, making it difficult to recommend appropriate widths, under different land-use and physiographic scenarios. The evidence to guide width determination generally had high levels of uncertainty. Despite the considerable amount of published riparian research, there was insufficient evidence to demonstrate that implemented widths achieved ecological objectives. We emphasise the need for managers to clearly articulate the objectives of proposed riparian management and carefully consider the environmental context. Monitoring ecological responses associated with different riparian buffer widths is essential to support future management decisions.Birgita D. Hansen, Paul Reich, Timothy R. Cavagnaro and P. S. Lak

Diversity, genetic mapping, and signatures of domestication in the carrot (Daucus carota L.) genome, as revealed by Diversity Arrays Technology (DArT) markers

Carrot is one of the most economically important vegetables worldwide, but genetic and genomic resources supporting carrot breeding remain limited. We developed a Diversity Arrays Technology (DArT) platform for wild and cultivated carrot and used it to investigate genetic diversity and to develop a saturated genetic linkage map of carrot. We analyzed a set of 900 DArT markers in a collection of plant materials comprising 94 cultivated and 65 wild carrot accessions. The accessions were attributed to three separate groups: wild, Eastern cultivated and Western cultivated. Twenty-seven markers showing signatures for selection were identified. They showed a directional shift in frequency from the wild to the cultivated, likely reflecting diversifying selection imposed in the course of domestication. A genetic linkage map constructed using 188 F2 plants comprised 431 markers with an average distance of 1.1 cM, divided into nine linkage groups. Using previously anchored single nucleotide polymorphisms, the linkage groups were physically attributed to the nine carrot chromosomes. A cluster of markers mapping to chromosome 8 showed significant segregation distortion. Two of the 27 DArT markers with signatures for selection were segregating in the mapping population and were localized on chromosomes 2 and 6. Chromosome 2 was previously shown to carry the Vrn1 gene governing the biennial growth habit essential for cultivated carrot. The results reported here provide background for further research on the history of carrot domestication and identify genomic regions potentially important for modern carrot breeding

Assessing changes in structural vegetation and soil properties following riparian restoration

Efforts are underway in many areas to restore riparian zones to arrest and/or reverse their degradation and the subsequent loss of the ecosystem services they provide. Despite strong links between edaphic conditions and riparian zone function, limited research has tested how soil properties respond to restoration, especially in an experimental context. With this important knowledge gap in mind, we established a field experiment to asssess structural vegetation and soil responses in the eight years following livestock exclusion and replanting in lowland streams in south-eastern Australia. On three streams, paired restored and control sites were experimentally established and we monitored vegetation (stem density, cover of bare ground and tree canopy, and loadings of organic matter), once beforehand, and then biennually after restoration. Selected soil properties (total carbon, total nitrogen, plant-available phosphorus) were sampled once shortly after restoration, then after another five years. Significant changes in structural vegetation occurred (e.g. decreased bare ground, increased plant stem density, organic matter, and canopy cover). In contrast, those soil properties did not respond. A mega-drought occurred throughout much of the study which was immediately followed by severe flooding. The floods redistributed organic matter at our study sites, with this effect mediated by vegetation structure: the probability of organic matter retention was positively correlated with groundcover and stem density of plants. The timing of flooding was also correlated with increased soil carbon and nitrogen, which could be due to increased productivity in these systems (for the former), or potentially due to increased fertiliser inputs or increased fixation (for the latter). Our study is the first to comprehensively and experimentally test how vegetation, litter layer and surface soil properties respond following riparian restoration, and will help guide the development and implementation of other monitoring programmes.Robin Hale, Paul Reich, Tom Daniel, Philip S. Lake, Timothy R. Cavagnar

Arbustos de la estepa patagónica : ¿adaptados a tolerar la sequía o el pastoreo?

61-70Features that confer plants tolerance to drought also provide tolerance to herbivory. Therefore, even the plants of arid zones with a short grazing history would be tolerant to herbivory. Evolutionary history of grazing in central and northwest Patagonian steppes has been considered brief and dominant spiny shrubs have been considered adapted to tolerate drought. Here, we present experimental evidences that question that conceptual model. (1) The three most conspicuous shrubs in the dominant community at south-western Chubut (Mulinum spinosum, Adesmia volckmanni and Senecio filaginoides) are not subjected to severe water stress conditions because their roots explore deep soil layers with relatively high water potentials almost all year. That is reflected in high leaf water potential, high isotopic discrimination against heavy carbon isotope and low response to rainfall. (2) Instead, the three shrubs show evasion herbivory strategies. M. spinosum and A. volckmanni have very aggressive thorns, while S. filaginoides has a high content of carbon-based secondary metabolites. These chemical compounds are believed to have an anti-herbivory role. Besides that, in two of these three species, levels of physical or chemical defences were increased under grazing conditions. (3) Finally, as defensive strategies do not preclude herbivore consumption in absolute terms, shrubs are important components of sheep diet. Sheeps eat leaves of non-chemically defended species and flowers of all of them. These evidences suggest that grazing pressure of native herbivores would have been high and persistent enough to promote natural selection processes that conducted to dominance of grazing resistant shrub genotypes

Scales that matter: guiding effective monitoring of soil properties in restored riparian zones

Considerable effort has been directed at restoring riparian zones to ensure they continue to provide ecosystem services and one of the most common aims of these activities is to reduce nutrients (in either water or soil) entering waterways. Vegetation plays a major role in nutrient interception, but nutrients in terrestrial ecosystems are strongly influenced by edaphic factors. Therefore understanding the effectiveness of riparian restoration efforts is dependent on knowledge of the complex and highly dynamic nature of nutrient cycling processes in riparian soils and their adjacent landscapes. Our primary aim was to assess the potential utility of a range of common soil indicators for monitoring responses to riparian restoration, and to use this information to provide guidance for more effective monitoring. A range of soil physiochemical properties in riparian zones and adjacent paddocks as a comparison were measured, incorporating both structural (e.g., bulk density) and functional (e.g., nitrogen) variables likely to differ in terms of both their responsiveness to restoration, and degree of natural spatial and temporal variation. Soil properties across the three spatial scales considered here (among creeks, among sites and within sites) varied considerably, particularly levels of phosphorus, ammonium and nitrate. Total organic carbon and total nitrogen were less variable and more uniform across all scales. Potential explanations for these patterns were explored by examining relationships between soil properties and vegetation measures, and between a subset of the most promising indicators (carbon, total nitrogen and bulk density, based on inherently low spatial variability) and adjacent land-use. Fertiliser inputs appear to be a strong determinant of soil phosphorus but otherwise soil properties were not strongly related to vegetation or adjacent land-use. For mineral N this is likely a reflection of the highly spatiotemporally dynamic nature of nutrient cycling in riparian zone soils. A better understanding of natural variability in soil properties will greatly aid in developing more effective monitoring programmes to assess potential changes in riparian soil properties. Management of riparian systems to recover soil ecosystem services will depend upon identifying effective ecological indicators that can be used as measures of progress towards restoration goals. This study represents a necessary first step towards guiding meaningful monitoring of soil properties at riparian zones subject to restoration efforts.Robin Hale, Paul Reicha, Tom Daniel, Philip S. Lake, Timothy R. Cavagnar

Robust Online Hamiltonian Learning

In this work we combine two distinct machine learning methodologies, sequential Monte Carlo and Bayesian experimental design, and apply them to the problem of inferring the dynamical parameters of a quantum system. We design the algorithm with practicality in mind by including parameters that control trade-offs between the requirements on computational and experimental resources. The algorithm can be implemented online (during experimental data collection), avoiding the need for storage and post-processing. Most importantly, our algorithm is capable of learning Hamiltonian parameters even when the parameters change from experiment-to-experiment, and also when additional noise processes are present and unknown. The algorithm also numerically estimates the Cramer-Rao lower bound, certifying its own performance.Comment: 24 pages, 12 figures; to appear in New Journal of Physic