365 research outputs found

    Spectroscopy of the variable K-dwarf UNSW-V-760: is it a pre-main-sequence pulsator?

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    The star UNSW-V-760 is a known variable, showing both flares and two non-sinusoidal periodicities. Availability of high signal-to-noise spectra reported in this paper has enabled a revision of the spectral type of this star to K3 IV-Vk. The star is a very rapid rotator (v sin i ∼ 140 km s−1), and the abundance of lithium appears to be enhanced. 48 radial velocity measurements were obtained over the course of three successive nights. These may show the same two frequencies detected photometrically, but there is some uncertainty in the interpretation. Application of pulsation theory suggests that photometric frequencies could be explained as low pulsation modes, but an excitation mechanism remains to be found.Department of HE and Training approved lis

    The Chandrayaan-1 X-ray spectrometer

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    The Chandrayaan-1 X-ray Spectrometer (C1XS) is a compact X-ray spectrometer for the Chandrayaan-1 lunar mission. It exploits heritage from the D-C1XS instrument on ESA’s SMART-1 mission. C1XS is designed to measure absolute and relative abundances of major rock-forming elements (principally Mg, Al, Si, Ti, Ca and Fe) over the lunar surface. The baseline design consists of 24 nadir pointing Swept Charge Device detectors, which provide high detection efficiency in the 1–7 keV range, which contains the X-ray fluorescence lines of the above elements of interest. Micromachined collimators provide a 14 degree FWHM FOV, equivalent to 25 km from 100 km altitude. A deployable door protects the instrument during launch and cruise, and also provides a 55Fe calibration X-ray source for detector calibration. Additional refinements compared to D-C1XS will result in a significantly improved energy resolution. To record the incident solar X-ray flux at the Moon, C1XS carries an X-ray Solar Monitor (XSM). C1XS will arrive at the Moon in the run up to the maximum of the solar cycle 24, and the expected high incident X-ray flux coupled to a 100 km circular polar orbit, will provide composition data accurate to better than 10% of major elemental abundances over the lunar surface

    From polyps to pixels: understanding coral reef resilience to local and global change across scales

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    Abstract Context Coral reef resilience is the product of multiple interacting processes that occur across various interacting scales. This complexity presents challenges for identifying solutions to the ongoing worldwide decline of coral reef ecosystems that are threatened by both local and global human stressors. Objectives We highlight how coral reef resilience is studied at spatial, temporal, and functional scales, and explore emerging technologies that are bringing new insights to our understanding of reef resilience. We then provide a framework for integrating insights across scales by using new and existing technological and analytical tools. We also discuss the implications of scale on both the ecological processes that lead to declines of reefs, and how we study those mechanisms. Methods To illustrate, we present a case study from Kāneʻohe Bay, Hawaiʻi, USA, linking remotely sensed hyperspectral imagery to within-colony symbiont communities that show differential responses to stress. Results In doing so, we transform the scale at which we can study coral resilience from a few individuals to entire ecosystems. Conclusions Together, these perspectives guide best practices for designing management solutions that scale from individuals to ecosystems by integrating multiple levels of biological organization from cellular processes to global patterns of coral degradation and resilience

    Behavioural activation for depressive symptoms in adults with severe to profound intellectual disabilities: modelling and initial feasibility study

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    Background Almost no research has been published reporting on evaluations of the effectiveness of psychological interventions for people with severe to profound intellectual disabilities and depression. This paper describes the development and initial feasibility testing of an adapted Behavioural Activation therapy (BeatIt2) for this population. Method Phase 1 of the study examined participant recruitment and willingness to be randomised in the context of a planned Randomised Controlled Trial (RCT). Phase 2 examined the feasibility of delivering the intervention. Results Twenty adults with a severe or profound intellectual disability and clinically significant depression were recruited to Phase 1 of the study. In Phase 2, there was 100% participant retention for those recruited to the study at 6-month follow-up. The BeatIt2 therapy was reported to be acceptable for participants. Conclusion COVID disruption meant that it was not possible to complete the planned feasibility RCT. The positive findings suggest that additional evaluation of BeatIt2 is warranted

    Self-regulation and self-control in exercise: The strength-energy model

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    Self-regulation is an important component of psychosocial theories of exercise behaviour and lack of self-regulatory skills are associated with low adherence to health-related exercise. This review presents a strength-energy model of self-control as an explanation of self-regulation in exercise contexts. The review will provide impetus for original research aimed at understanding exercise behaviour and help develop recommendations for exercise promotion. In the model, self-control is conceptualized as a global but limited resource. Engaging in actions requiring self-control depletes resources leading to self-regulatory failure. Self-control resource depletion is reduced through rest and frequent training on self-control. The expectation of the need to exert self-control in future leads to a conservation of self-control resources. Proposed mechanisms for self-control resource depletion include changes in physiological markers and blood glucose levels. Based on our review, we propose an integrated model of self-regulation incorporating hypotheses from the strength-energy model with those from traditional psychosocial models of exercise behaviour. Recommendations for future research include incorporating hypotheses from the strength-energy model into theories of self-presentation and interpersonal relations in exercise. Practical recommendations aimed at minimising self-control depletion in exercise include the provision of advice on nutrition and recovery, self-control training and motivational and implementation intention strategies

    Organizing Engineering Work - A Comparative-Analysis

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    This article analyzes the organization of engineering work in six industrial capitalist countries. It identifies four major models for the organization of engineering work; the engineering profession did not succeed in achieving professional “closure” in any of the six countries under review. A review of the historical evolution of the organization of engineering work in each of the six countries reveals that engineering has been shaped by a complex interaction among the profession itself, employers, the state, labor, and preindustrial forces. However, none of the national variations on the four models for organizing engineering labor is stable or without internal contradiction because of the ambiguous “intermediate” position of engineers

    Genetic modifiers in rare disorders: the case of fragile X syndrome.

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    Methods employed in genome-wide association studies are not feasible ways to explore genotype-phenotype associations in rare disorders due to limited statistical power. An alternative approach is to examine relationships among specific single nucleotide polymorphisms (SNPs), selected a priori, and behavioural characteristics. Here, we adopt this strategy to examine relationships between three SNPs (5-HTTLPR, MAOA, COMT) and specific clinically-relevant behaviours that are phenotypic of fragile X syndrome (FXS) but vary in severity and frequency across individuals. Sixty-four males with FXS participated in the current study. Data from standardised informant measures of challenging behaviour (defined as physical aggression, property destruction, stereotyped behaviour, and self-injury), autism symptomatology, attention-deficit-hyperactivity-disorder characteristics, repetitive behaviour and mood/interest and pleasure were compared between each SNP genotype. No association was observed between behavioural characteristics and either 5-HTTLPR (serotonin) or MAOA (monoamine oxidase) genotypes. However, compared to the COMT (dopamine) AG and GG genotypes, the AA genotype was associated with greater interest and pleasure in the environment, and with reduced risk for property destruction, stereotyped behaviour and compulsive behaviour. The results suggest that common genetic variation in the COMT genotype affecting dopamine levels in the brain may contribute to the variability of challenging and repetitive behaviours and interest and pleasure in this population. This study identifies a role for additional genetic risk in understanding the neural and genetic mechanisms contributing to phenotypic variability in neurodevelopmental disorders, and highlights the merit of investigating SNPs that are selected a priori on a theoretical basis in rare populations
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