69 research outputs found

    The Evolution of Bat Vestibular Systems in the Face of Potential Antagonistic Selection Pressures for Flight and Echolocation

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    PMCID: PMC3634842This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Conceptualizing Quality in Software Industry

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    This paper investigates the different software quality perceptions from the different stakeholders’ perspectives and presents a critique to previously developed quality models and measurement theory frameworks associated. It emphasizes the rationale beyond the selection of the Goal Question Metric (GQM) as an evaluation method for the development of the software project with the desired quality needs satisfying the software system. Then it ends up with several concluding remarks that pinpoint the main discussion points and offers guidance for further research

    The Glial Regenerative Response to Central Nervous System Injury Is Enabled by Pros-Notch and Pros-NFκB Feedback

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    Organisms are structurally robust, as cells accommodate changes preserving structural integrity and function. The molecular mechanisms underlying structural robustness and plasticity are poorly understood, but can be investigated by probing how cells respond to injury. Injury to the CNS induces proliferation of enwrapping glia, leading to axonal re-enwrapment and partial functional recovery. This glial regenerative response is found across species, and may reflect a common underlying genetic mechanism. Here, we show that injury to the Drosophila larval CNS induces glial proliferation, and we uncover a gene network controlling this response. It consists of the mutual maintenance between the cell cycle inhibitor Prospero (Pros) and the cell cycle activators Notch and NFκB. Together they maintain glia in the brink of dividing, they enable glial proliferation following injury, and subsequently they exert negative feedback on cell division restoring cell cycle arrest. Pros also promotes glial differentiation, resolving vacuolization, enabling debris clearance and axonal enwrapment. Disruption of this gene network prevents repair and induces tumourigenesis. Using wound area measurements across genotypes and time-lapse recordings we show that when glial proliferation and glial differentiation are abolished, both the size of the glial wound and neuropile vacuolization increase. When glial proliferation and differentiation are enabled, glial wound size decreases and injury-induced apoptosis and vacuolization are prevented. The uncovered gene network promotes regeneration of the glial lesion and neuropile repair. In the unharmed animal, it is most likely a homeostatic mechanism for structural robustness. This gene network may be of relevance to mammalian glia to promote repair upon CNS injury or disease

    Financial incentives to improve adherence to antipsychotic maintenance medication in non-adherent patients: a cluster randomised controlled trial

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    Background: Poor adherence to long-term antipsychotic injectable (LAI) medication in patients with psychotic disorders is associated with a range of negative outcomes. No psychosocial intervention has been found to be consistently effective in improving adherence. Objectives: To test whether or not offering financial incentives is effective and cost-effective in improving adherence and to explore patient and clinician experiences with such incentives. Design: A cluster randomised controlled trial with economic and nested qualitative evaluation. The intervention period lasted for 12 months with 24 months’ follow-up. The unit of randomisation was mental health teams in the community. Setting: Community teams in secondary mental health care. Participants: Patients with a diagnosis of schizophrenia, schizoaffective psychosis or bipolar illness, receiving ≤ 75% of their prescribed LAI medication. In total, 73 teams with 141 patients (intervention n = 78 and control n = 63) were included. Interventions: Participants in the intervention group received £15 for each LAI medication. Patients in the control group received treatment as usual. Main outcome measures: Primary outcome: adherence to LAI medication (the percentage of received out of those prescribed). Secondary outcomes: percentage of patients with at least 95% adherence; clinical global improvement; subjective quality of life; satisfaction with medication; hospitalisation; adverse events; and costs. Qualitative evaluation: semistructured interviews with patients in the intervention group and their clinicians. Results: Primary outcome: outcome data were available for 131 patients. Baseline adherence was 69% in the intervention group and 67% in the control group. During the intervention period, adherence was significantly higher in the intervention group than in the control group (85% vs. 71%) [adjusted mean difference 11.5%, 95% confidence interval (CI) 3.9% to 19.0%; p = 0.003]. Secondary outcome: patients in the intervention group showed statistically significant improvement in adherence of at least 95% (adjusted odds ratio 8.21, 95% CI 2.00 to 33.67; p = 0.003) and subjective quality of life (difference in means 0.71, 95% CI 0.26 to 1.15; p = 0.002). Follow-ups: after incentives stopped, adherence did not differ significantly between groups, neither during the first 6 months (adjusted difference in means –7.4%, 95% CI –17.0% to 2.1%; p = 0.175) nor during the period from month 7 to month 24 (difference in means –5.7%, 95% CI –13.1% to 1.7%; p = 0.130). Cost-effectiveness: the average costs of the financial incentives was £303. Overall costs per patient were somewhat higher in the intervention group, but the difference was not significant. Semistructured interviews: the majority of patients and clinicians reported positive experiences with the incentives beyond their monetary value. These included improvement in the therapeutic relationship. The majority of both patients and clinicians perceived no negative impact after the intervention was stopped after 1 year. Conclusions: Financial incentives are effective in improving adherence to LAI medication. Health-care costs (including costs of the financial incentive) are unlikely to be increased substantially by this intervention. Once the incentives stop, the advantage is not maintained. The experiences of both patients and clinicians are largely, but not exclusively, positive. Whether or not financial incentives are effective for patients with more favourable background, those on oral mediation or for shorter or longer time periods remains unknown. Trial registration: Current Controlled Trials ISRCTN77769281. Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 70. See the NIHR Journals Library website for further project information

    Grid Cells, Place Cells, and Geodesic Generalization for Spatial Reinforcement Learning

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    Reinforcement learning (RL) provides an influential characterization of the brain's mechanisms for learning to make advantageous choices. An important problem, though, is how complex tasks can be represented in a way that enables efficient learning. We consider this problem through the lens of spatial navigation, examining how two of the brain's location representations—hippocampal place cells and entorhinal grid cells—are adapted to serve as basis functions for approximating value over space for RL. Although much previous work has focused on these systems' roles in combining upstream sensory cues to track location, revisiting these representations with a focus on how they support this downstream decision function offers complementary insights into their characteristics. Rather than localization, the key problem in learning is generalization between past and present situations, which may not match perfectly. Accordingly, although neural populations collectively offer a precise representation of position, our simulations of navigational tasks verify the suggestion that RL gains efficiency from the more diffuse tuning of individual neurons, which allows learning about rewards to generalize over longer distances given fewer training experiences. However, work on generalization in RL suggests the underlying representation should respect the environment's layout. In particular, although it is often assumed that neurons track location in Euclidean coordinates (that a place cell's activity declines “as the crow flies” away from its peak), the relevant metric for value is geodesic: the distance along a path, around any obstacles. We formalize this intuition and present simulations showing how Euclidean, but not geodesic, representations can interfere with RL by generalizing inappropriately across barriers. Our proposal that place and grid responses should be modulated by geodesic distances suggests novel predictions about how obstacles should affect spatial firing fields, which provides a new viewpoint on data concerning both spatial codes

    Restoration of soil quality using biochar and brown coal waste: A review

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    Soils in intensively farmed areas of the world are prone to degradation. Amendment of such soils with organic waste materials attempts to restore soil quality. Organic amendments are heterogeneous media, which are a source of soil organic matter (SOM) and maintain or restore chemical, physical, biological and ecological functionality. More specifically, an increase in SOM can influence the soil microclimate, microbial community structure, biomass turnover and mineralisation of nutrients. The search is on-going for locally sourced alternatives as many forms may be costly or geographically limiting. The present review focuses on a heterogeneous group of amendments i.e. biochar and brown coal waste (BCW). Both biochar (made from a variety of feedstocks at various temperatures) and BCW (mined extensively) are options that have worldwide applicability. These materials have very high C contents and soil stability, therefore can be used for long-term C sequestration to abate greenhouse gas emissions and as conditioners to improve soil quality. However, biochar is costly for large-scale applications and BCW may have inherently high moisture and pollutant contents. Future studies should focus on the long-term application of these amendments and determine the physicochemical properties of the soil, bioavailability of soil contaminants, diversity of soil communities and productivity of selected crops. Furthermore, the development of in situ technologies to lower production and processing costs of biochar and BCW would improve their economic feasibility for large-scale application

    Versailles Project on Advanced Materials and Standards interlaboratory study on intensity calibration for x-ray photoelectron spectroscopy instruments using low-density polyethylene

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    We report the results of a Versailles Project on Advanced Materials and Standards interlaboratory study on the intensity scale calibration of x-ray photoelectron spectrometers using low-density polyethylene (LDPE) as an alternative material to gold, silver, and copper. An improved set of LDPE reference spectra, corrected for different instrument geometries using a quartz-monochromated Al Kα x-ray source, was developed using data provided by participants in this study. Using these new reference spectra, a transmission function was calculated for each dataset that participants provided. When compared to a similar calibration procedure using the NPL reference spectra for gold, the LDPE intensity calibration method achieves an absolute offset of ∼3.0% and a systematic deviation of ±6.5% on average across all participants. For spectra recorded at high pass energies (≥90 eV), values of absolute offset and systematic deviation are ∼5.8% and ±5.7%, respectively, whereas for spectra collected at lower pass energies (<90 eV), values of absolute offset and systematic deviation are ∼4.9% and ±8.8%, respectively; low pass energy spectra perform worse than the global average, in terms of systematic deviations, due to diminished count rates and signal-to-noise ratio. Differences in absolute offset are attributed to the surface roughness of the LDPE induced by sample preparation. We further assess the usability of LDPE as a secondary reference material and comment on its performance in the presence of issues such as variable dark noise, x-ray warm up times, inaccuracy at low count rates, and underlying spectrometer problems. In response to participant feedback and the results of the study, we provide an updated LDPE intensity calibration protocol to address the issues highlighted in the interlaboratory study. We also comment on the lack of implementation of a consistent and traceable intensity calibration method across the community of x-ray photoelectron spectroscopy (XPS) users and, therefore, propose a route to achieving this with the assistance of instrument manufacturers, metrology laboratories, and experts leading to an international standard for XPS intensity scale calibration

    Brazilian cave heritage under siege

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