550 research outputs found

    Tribology of particle suspensions in rolling-sliding soft contacts

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    We investigate the lubrication of microsphere suspensions between compliant substrates, and probe the influence of matrix viscosity, particle phase volume, surface roughness and wetting, and slide-to-roll ratio (SRR). In general, the suspensions behave as a continuum in the elastohydrodynamic regime provided the film thickness, which is predicted from the product of speed and viscosity, is greater than the particle diameter. Below this, the frictional response is characteristic of the mixed and boundary regimes. In the boundary regime, friction is independent of phase volume above 5% and it is governed by the rolling friction associated with particles being entrained into the contact that is independent of SRR, which is made possible by substrate deformation. This study provides a benchmark for soft-tribology and biotribology studies involving more complex particle suspensions and particle-containing soft materials

    The impact of brief intensive trauma-focused treatment for PTSD on symptoms of borderline personality disorder

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    Objective: To investigate the effects of a brief, intensive, direct trauma-focused treatment programme for individuals with PTSD on BPD symptom severity. Methods: Individuals (n = 72) with severe PTSD (87.5% had one or more comorbidities; 52.8% fulfilled the criteria for the dissociative subtype of PTSD) due to multiple traumas (e.g. 90.3% sexual abuse) participated in an intensive eight-day trauma-focused treatment programme consisting of eye movement desensitization and reprocessing (EMDR) and prolonged exposure (PE) therapy, physical activity, and psychoeducation. Treatment did not include any form of stabilization (e.g. emotion regulation training) prior to trauma-focused therapy. Assessments took place at pre- and post-treatment (Borderline Symptom List, BSL-23; PTSD symptom severity, Clinician Administered PTSD Scale for DSM-5, CAPS-5), and across the eight treatment days (PTSD Checklist, PCL-5). Results: Treatment resulted in significant decreases of BPD symptoms (Cohen’s d = 0.70). Of the 35 patients with a positive screen for BPD at pre-treatment, 32.7% lost their positive screen at post-treatment. No adverse events nor dropouts occurred during the study time frame, and none of the patients experienced symptom deterioration in response to treatment. Conclusion: The results suggest that an intensive trauma-focused treatment is a feasible and safe treatment for PTSD patients with clinically elevated symptoms of BPD, and that BPD symptoms decrease along with the PTSD symptoms

    Microbiome variation in corals with distinct depth distribution ranges across a shallow-mesophotic gradient (15-85 m)

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    Mesophotic coral ecosystems (MCEs) are generally poorly studied, and our knowledge of lower MCEs (below 60 m depth) is largely limited to visual surveys. Here, we provide a first detailed assessment of the prokaryotic community associated with scleractinian corals over a depth gradient to the lower mesophotic realm (15-85 m). Specimens of three Caribbean coral species exhibiting differences in their depth distribution ranges (Agaricia grahamae, Madracis pharensis and Stephanocoenia intersepta) were collected with a manned submersible on the island of Cura double dagger ao, and their prokaryotic communities assessed using 16S rRNA gene sequencing analysis. Corals with narrower depth distribution ranges (depth-specialists) were associated with a stable prokaryotic community, whereas corals with a broader niche range (depth-generalists) revealed a higher variability in their prokaryotic community. The observed depth effects match previously described patterns in Symbiodinium depth zonation. This highlights the contribution of structured microbial communities over depth to the coral's ability to colonize a broader depth range.Austrian Science Fund (FWF); Catlin Group Limited; Global Change Institute; Eddie Bauer Grant for Expeditions by The Explorers Club; Marie Curie Fellowship [FP7-299320]; Lise Meitner Program of the Austrian Science Fund (FWF) [M1363-B20]info:eu-repo/semantics/publishedVersio

    Genetic Divergence across Habitats in the Widespread Coral Seriatopora hystrix and Its Associated Symbiodinium

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    Background: Coral reefs are hotspots of biodiversity, yet processes of diversification in these ecosystems are poorly understood. The environmental heterogeneity of coral reef environments could be an important contributor to diversification, however, evidence supporting ecological speciation in corals is sparse. Here, we present data from a widespread coral species that reveals a strong association of host and symbiont lineages with specific habitats, consistent with distinct, sympatric gene pools that are maintained through ecologically-based selection.\ud \ud Methodology/Principal Findings: Populations of a common brooding coral, Seriatopora hystrix, were sampled from three adjacent reef habitats (spanning a ~30 m depth range) at three locations on the Great Barrier Reef (n = 336). The populations were assessed for genetic structure using a combination of mitochondrial (putative control region) and nuclear (three microsatellites) markers for the coral host, and the ITS2 region of the ribosomal DNA for the algal symbionts (Symbiodinium). Our results show concordant genetic partitioning of both the coral host and its symbionts across the different habitats, independent of sampling location.\ud \ud Conclusions/Significance: This study demonstrates that coral populations and their associated symbionts can be highly structured across habitats on a single reef. Coral populations from adjacent habitats were found to be genetically isolated from each other, whereas genetic similarity was maintained across similar habitat types at different locations. The most parsimonious explanation for the observed genetic partitioning across habitats is that adaptation to the local environment has caused ecological divergence of distinct genetic groups within S. hystrix

    On X-Ray Waveguiding in Nanochannels: Channeling Formalism

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    The question on X-ray extreme focusing (smallest reachable spot size) brings us to the idea for using the wave features of X-ray propagation in media. As known, wave features are revealed at propagation in ultra-narrow collimators as well as at glancing reflection from smooth flat and/or strongly curved surfaces. All these phenomena can be described within the general formalism of X-ray channeling.Comment: by the invited lecture at ISRP-1

    Mesophotic coral ecosystems of the Great Barrier Reef are understudied and underexplored

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    Mesophotic coral ecosystems (MCEs) are characterized by the presence of photosynthetically active organisms such as corals and algae, and associated communities at depths ranging from 30 to 150 m in tropical and subtropical regions. Due to the increased awareness of the potential importance of these reefs as an integral part of coral reef ecosystems (i.e., deep reef refuge, specialized biodiversity, transition zone between shallow and deep-sea environments, and recreational and intrinsic values), interest from the scientific community has grown around the world over the last two decades. Several nations have already made management declarations and started to extend marine protected areas and fishery management to MCEs. The estimated area of Australian MCEs is likely equivalent to that of shallow reef ecosystems down to 30 m; however, Australian MCEs attract limited research effort compared to other major coral reef regions around the world. In this perspective, we briefly explore the reasons for this scarcity of research on mesophotic ecosystems of the Great Barrier Reef (GBR) of Australia (e.g., strict diving regulations, new researchers’ involvement, and logistics and cost). At present, research efforts on the mesophotic ecosystems of the GBR are in decline and if this trajectory is maintained, the global disparity in knowledge between MCEs near Australia and those from the other main coral reef regions worldwide will sharpen deeply. We call for action from the research community, grant agencies, and decision-makers toward a wider understanding of these important ecosystems in Australia

    Fully remote intensive trauma-focused treatment for PTSD and complex PTSD

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    Background: It is unknown whether remotely delivered intensive trauma-focused therapy not only is an effective treatment for PTSD, but also for Complex PTSD. Objective: Testing the hypothesis that a brief, fully remotely administered intensive trauma-focused treatment programme for individuals with PTSD and Complex PTSD would be safe, and associated with a significant decline of the corresponding symptoms and diagnostic status. Method: The treatment sample consisted of 73 consecutive patients diagnosed with PTSD according to the CAPS-5. According to the ITQ (n = 70) 33 (47.1%) patients also fulfilled the diagnostic criteria of Complex PTSD. The 4-day treatment programme contained a combination of prolonged exposure, EMDR therapy, physical activities and psycho-education. Treatment response was measured using the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), the PTSD Checklist for DSM-5 (PCL-5), and the International Trauma Questionnaire (ITQ) for classifying Complex PTSD and indexing disturbances in self-organization (DSO). Results: Overall CAPS-5, PCL-5, and ITQ-DSO scores decreased significantly from pre- to post-treatment (Cohen’s ds 2.12, 1.59, and 1.18, respectively), while the decrease was maintained to six months follow-up. At post-treatment, 60 patients (82.2%) no longer met the diagnostic criteria of PTSD, while the proportion of patients with Complex PTSD decreased from 47.1% to 10.1%. No drop out, and no personal adverse events occurred. Conclusions: The results support the notion that intensive, trauma-focused treatment is feasible, safe and associated with a large decrease in PTSD and Complex PTSD symptoms, even when it is brief, and applied fully remote

    Native Speaker Perceptions of Accented Speech: The English Pronunciation of Macedonian EFL Learners

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    The paper reports on the results of a study that aimed to describe the vocalic and consonantal features of the English pronunciation of Macedonian EFL learners as perceived by native speakers of English and to find out whether native speakers who speak different standard variants of English perceive the same segments as non-native. A specially designed computer web application was employed to gather two types of data: a) quantitative (frequency of segment variables and global foreign accent ratings on a 5-point scale), and b) qualitative (open-ended questions). The result analysis points out to three most frequent markers of foreign accent in the English speech of Macedonian EFL learners: final obstruent devoicing, vowel shortening and substitution of English dental fricatives with Macedonian dental plosives. It also reflects additional phonetic aspects poorly explained in the available reference literature such as allophonic distributional differences between the two languages and intonational mismatch
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