7440 research outputs found
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Cuttlefish perform multiple agonistic displays to communicate a hierarchy of threats
No full textMany animals produce multiple displays during agonistic interactions, but the roles of these displays often remain ambiguous. The hierarchical signaling hypothesis has been proposed to explain their occurrence and posits that different displays convey different levels of aggressive intent, allowing signalers to communicate graded series of threats. This hypothesis suggests that low-risk signals, typically performed at the beginning stages of an interaction, are strong predictors of high-risk signals but weak predictors of physical aggression. High-risk signals, typically produced at later stages of an interaction, are strong predictors of physical aggression. We used giant Australian cuttlefish, Sepia apama, to test these predictions. We combined field observations and laboratory video playback experiments to determine whether (i) male cuttlefish produce specific sequences of displays, (ii) displays in early stages of an interaction predict displays in later stages of an interaction, and (iii) displays produced in later stages of an interaction provide reliable predictors of physical aggression. Field observations suggested that males progressed from low-risk to high-risk signals (i.e., visual signaling to physical aggression). Video playback results zrevealed that the low-risk frontal display, produced during early stages of an interaction, conveys reliable information about the cuttlefish’s intent to escalate to later stages of visual signaling. Both the shovel and lateral displays were produced during the later stages of signaling and were reliable predictors of subsequent physical aggression. Our study supports the hierarchical signaling hypothesis and provides new empirical insights into how cuttlefish use progressive visual signaling to convey increasing levels of threat.13 page(s
A Method to enhance the use of interaural time differences for cochlear implants in reverberant environments
No full textThe ability of normal-hearing (NH) listeners to exploit interaural time difference (ITD) cues conveyed in the modulated envelopes of high-frequency sounds is poor compared to ITD cues transmitted in the temporal fine structure at low frequencies. Sensitivity to envelope ITDs is further degraded when envelopes become less steep, when modulation depth is reduced, and when envelopes become less similar between the ears, common factors when listening in reverberant environments. The vulnerability of envelope ITDs is particularly problematic for cochlear implant (CI) users, as they rely on information conveyed by slowly varying amplitude envelopes. Here, an approach to improve access to envelope ITDs for CIs is described in which, rather than attempting to reduce reverberation, the perceptual saliency of cues relating to the source is increased by selectively sharpening peaks in the amplitude envelope judged to contain reliable ITDs. Performance of the algorithm with room reverberation was assessed through simulating listening with bilateral CIs in headphone experiments with NH listeners. Relative to simulated standard CI processing, stimuli processed with the algorithm generated lower ITD discrimination thresholds and increased extents of laterality. Depending on parameterization, intelligibility was unchanged or somewhat reduced. The algorithm has the potential to improve spatial listening with CIs.14 page(s
The Hα surface brightness-radius relation : a robust statistical distance indicator for planetary nebulae
No full textMeasuring the distances to Galactic planetary nebulae (PNe) has been an intractable problem for many decades. We have now established a robust optical statistical distance indicator, the Hα surface brightness–radius or SHα–r relation, which addresses this problem. We developed this relation from a critically evaluated sample of primary calibrating PNe. The robust nature of the method results from our revised calibrating distances with significantly reduced systematic uncertainties, and the recent availability of high-quality data, including updated nebular diameters and integrated Hα fluxes. The SHα–r technique is simple in its application, requiring only an angular size, an integrated Hα flux, and the reddening to the PN. From these quantities, an intrinsic radius is calculated, which when combined with the angular size, yields the distance directly. Furthermore, we have found that optically thick PNe tend to populate the upper bound of the trend, while optically thin PNe fall along the lower boundary in the SHα–r plane. This enables sub-trends to be developed which offer even better precision in the determination of distances, as good as 18 per cent in the case of optically thin, high-excitation PNe. This is significantly better than any previous statistical indicator. We use this technique to create a catalogue of statistical distances for over 1100 Galactic PNe, the largest such compilation in the literature to date. Finally, in an appendix, we investigate both a set of transitional PNe and a range of PN mimics in the SHα–r plane, to demonstrate its use as a diagnostic tool. Interestingly, stellar ejecta around massive stars plot on a tight locus in SHα–r space with the potential to act as a separate distance indicator for these objects.30 page(s
SWATH mass spectrometry performance using extended peptide MS/MS assay libraries
No full textThe use of data-independent acquisition methods such as SWATH for mass spectrometry based proteomics is usually performed with peptide MS/MS assay libraries which enable identification and quantitation of peptide peak areas. Reference assay libraries can be generated locally through information dependent acquisition, or obtained from community data repositories for commonly studied organisms. However, there have been no studies performed to systematically evaluate how locally generated or repository-based assay libraries affect SWATH performance for proteomic studies. To undertake this analysis, we developed a software workflow, SwathXtend, which generates extended peptide assay libraries by integration with a local seed library and delivers statistical analysis of SWATH-quantitative comparisons. We designed test samples using peptides from a yeast extract spiked into peptides from human K562 cell lysates at three different ratios to simulate protein abundance change comparisons. SWATH-MS performance was assessed using local and external assay libraries of varying complexities and proteome compositions. These experiments demonstrated that local seed libraries integrated with external assay libraries achieve better performance than local assay libraries alone, in terms of the number of identified peptides and proteins and the specificity to detect differentially abundant proteins. Our findings show that the performance of extended assay libraries is influenced by the MS/MS feature similarity of the seed and external libraries, while statistical analysis using multiple testing corrections increases the statistical rigor needed when searching against large extended assay libraries.14 page(s
Quantifying the hospitalised morbidity and mortality attributable to traumatic injury using a population-based matched cohort in Australia
No full textObjectives: To quantify the 12-month hospitalised morbidity and mortality attributable to traumatic injury using a population-based matched cohort in Australia. Setting: New South Wales, Queensland and South Australia, Australia. Participants: Individuals ≥18years who had an injury-related hospital admission in 2009 formed the injured cohort. The non-injured comparison cohort was randomly selected from the electoral roll and was matched 1:1 on age, gender and postcode of residence at the date of the index injury admission of their matched counterpart. Primary outcome measures: Using linked emergency department presentation, hospital admission and mortality records from 1 January 2008 to 31 December 2010 for both the injured and non-injured cohorts, 12-month mortality and pre-index and post-index injury hospital service use was examined. Adjusted rate ratios and attributable risk were calculated. Results: There were 167600 individuals injured in 2009 and admitted to hospital in New South Wales, South Australia or Queensland with a matched comparison. The injured cohort had 3 times higher proportion of having ≥1 comorbidity preinjury, higher preinjury hospital service use, and a higher 12-month mortality compared with a non-injured comparison group. The injured cohort had 2.20 (95% CI 2.12 to 2.28) times higher rate of hospital admissions in the 12 months post the index injury admission compared with the non-injured comparison cohort. Injury was a likely contributory factor in at least 55% of hospitalisations within 12 months of the index injury hospitalisation. Conclusions: Individuals who had an injury-related hospitalisation had higher mortality and are hospitalised at increased rates for many months postinjury. While comorbid conditions are significant, they do not account for the differences in outcomes. This study contributes to informing research efforts on better quantifying the attributable burden of hospitalised injury-related disability and mortality in Australia.9 page(s
Internet-delivered treatment for older adults with anxiety and depression : implementation of the Wellbeing Plus Course in routine clinical care and comparison with research trial outcomes
No full textBackground: The Wellbeing Plus Course is an internet-delivered psychological intervention for older adults with anxiety or depression. Aims: To compare the effectiveness of the Wellbeing Plus Course in a public health setting (clinic group) with its efficacy in a randomised controlled trial (research group). METHOD: Participants (n=949) were Australian adults aged 60 and above. Primary outcome measures were the Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder scale (GAD-7). Results: Initial symptom severity was higher in the clinic group and course completion was lower. Both groups showed significant symptom reductions at post-treatment and were satisfied with the treatment. Results were maintained at 3-month follow-up. Within-group symptom changes were comparable between settings; there were no between-group differences on primary outcomes or satisfaction. Conclusions: The Wellbeing Plus Course is as effective and acceptable in routine clinical care, as it is in controlled research trials.7 page(s
Identifying key sedimentary indicators of geomorphic structure and function of upland swamps in the Blue Mountains for use in condition assessment and monitoring
No full textTemperate Highland Peat Swamps on Sandstone (THPSS) are located at the headwaters of streams on low relief plateaus of Eastern Australia. Swamp sediment structure has a direct link to the high water tables, element cycling and carbon sequestration that are the characteristic functions of these systems. By comparing the sediment structure of intact swamps and channelised fills, we can gain an understanding of how changes in swamp geomorphology change both swamp structure and function. We examined the sedimentology of six intact and six channelised fill swamps in the Blue Mountains NSW, Australia. There were significant differences in texture, unit thickness, Carbon: Nitrogen (C:N) ratios and moisture content between intact swamps and channelised fills. The presence and thickness of unmodified contemporary sand layers in almost all channelised fills and its absence in almost all intact swamps was a distinctive structural difference. The two functional swamp layers, in terms of water and carbon storage were almost double the mean thickness in intact swamps than in channelised fills. Moisture content was 30% higher in intact swamps than in channelised fills. Mean C: N ratios for channelised fills were 25% lower than that of intact swamps. Peat forming potential, as defined by C:N ratios > 27, started at a greater depth in the sediment profile (0.9 m lower) in channelised fills than in intact swamps. It is clear from this study that these structural and functional indicators are important for assessing swamp condition and can also be useful in designing monitoring programs for management and rehabilitation that target key structural attributes that produce and maintain swamp function.14 page(s
Efficacy of anorectal biofeedback in scleroderma patients with fecal incontinence : a case-control study
No full textObjective: To determine whether anorectal biofeedback therapy can improve the symptoms of fecal incontinence (FI) in patients with scleroderma when compared to patients with functional FI, and also whether there is any effect on anorectal physiology or quality of life (QOL). FI in patients with scleroderma is highly prevalent and is associated with significant loss of QOL. Biofeedback has been proven to be an effective treatment for functional FI, but there are no data to support its use in scleroderma. Materials and methods: 13 consecutive female patients (median age 59, IQR 47–65 years) with scleroderma, and 26 age- and parity-matched female patients with functional FI (disease controls, 2:1), underwent biofeedback therapy for management of FI. Fecal incontinence severity index (FISI), anorectal physiology, feeling of control and QOL were collected before and after 6 weeks of biofeedback therapy, with additional scoring repeated at 6-month follow-up. Results: After biofeedback treatment FISI, feeling of control and QOL significantly improved in both groups (p < 0.005). There was no difference in the degree in improvement in physiology, FISI or QOL between scleroderma patients and functional FI patients. Long-term improvement in FISI and control were seen in both groups and for QOL only in the scleroderma cohort (p < 0.05). Conclusions: Patients with scleroderma benefit from biofeedback therapy to the same extent as that achieved in patients with functional FI. There are significant improvements in symptoms, physiology and QOL. Biofeedback is an effective, low-risk treatment option in this patient group.6 page(s
Constraint induced aphasia therapy : volunteer-led, unconstrained and less intense delivery can be effective
No full textBackground: Constraint Induced Aphasia Therapy (CIAT) has been shown to be effective in the treatment of aphasia, but clinicians have expressed concern regarding how far CIAT is practical to implement in clinical practice. Objective: To determine whether CIAT delivered in a less-intense, lower dose, reduced constraint and volunteer-led format could produce positive outcomes in people with chronic aphasia. Methods: Two groups were run, each with two people with chronic aphasia. Treatment involved a standard CIAT card-exchange game, supplemented by a home activity. Spoken language was required for responses but alternative modalities of communication were also permitted. Each group was led by a trained volunteer, lasted 90 minutes and was delivered twice a week for four weeks. Results: Three of the four participants showed significant improvements in target word retrieval following treatment. No significant improvements were observed for untreated stimuli or language tasks. Two participants showed increases in the elaboration of their responses, and the same two showed an increase in the frequency with which they engaged in communication activities. Conclusions: Clear gains in performance were observed for the majority of people with aphasia who participated in a less intense format, considerably lower dose and less constrained form of CIAT led by trained volunteers. This suggests that this ‘clinically realistic’ service delivery model for CIAT could be added to the clinical repertoire of speech pathologists.13 page(s
Impact of the representation of stomatal conductance on model projections of heatwave intensity
No full textStomatal conductance links plant water use and carbon uptake, and is a critical process for the land surface component of climate models. However, stomatal conductance schemes commonly assume that all vegetation with the same photosynthetic pathway use identical plant water use strategies whereas observations indicate otherwise. Here, we implement a new stomatal scheme derived from optimal stomatal theory and constrained by a recent global synthesis of stomatal conductance measurements from 314 species, across 56 field sites. Using this new stomatal scheme, within a global climate model, subtantially increases the intensity of future heatwaves across Northern Eurasia. This indicates that our climate model has previously been under-predicting heatwave intensity. Our results have widespread implications for other climate models, many of which do not account for differences in stomatal water-use across different plant functional types, and hence, are also likely under projecting heatwave intensity in the future.7 page(s