1,782 research outputs found
Increased Salinity and Water Depth as Constraints on Growth of Freshwater Marsh Plants.
Three experiments were conducted to evaluate the response of freshwater-oligohaline marsh macrophytes to increased water depth and salinity. In the first experiment, marsh sods containing Sagittaria lancifolia were manipulated in the field to decrease elevation (i.e., increase water depth) by 7.5 and 15 cm. Marsh sods at 15 cm below the marsh surface had the lowest redox potential and highest interstitial water sulfide concentration. Plants in the 15-cm water depth treatment had higher mean and maximum leaf heights than disturbed control plants, but aboveground biomass was not affected. In the second study, the effects of salinity pulses on plant growth and ability to recover following stress alleviation were examined in a greenhouse experiment that included monocultures of four species: Eleocharis palustris, Panicum hemitomon, Sagittaria lancifolia, and Scirpus americanus. Effects of final salinity reached, salinity influx rate, and duration of exposure were investigated. All species responded to final salinity level to a greater degree than salinity influx rate. The magnitude of growth suppression increased for all species with exposure duration. The species were ranked as follows in order from least to most salt tolerant: Panicum hemitomon Sagittaria lancifolia Eleocharis palustris Scirpus americanus. Within a species, ability to recover under freshwater conditions varied with final salinity level and duration of exposure, and to a lesser extent with salinity influx rate. Scirpus americanus was the only species able to recover under all experimental conditions. In the final greenhouse experiment, two common oligohaline marsh communities were subjected to salinity pulses; influx rate, duration of exposure, and water depth were manipulated. The two communities included one species in common, Sagittaria lancifolia; the sub-dominants were Eleocharis palustris and Scirpus americanus in community 1 and community 2, respectively. Species richness in both communities was reduced in the most extreme treatment. Community 1 total biomass and stem density were reduced, as were biomass and stem density for both dominant species. Community 2 had reduced biomass and stem density overall and for Sagittaria lancifolia; Scirpus americanus was not affected. Considered together, the three experiments indicate that different responses of existing plant species to environmental stressors can ultimately influence community structure and composition
Building Civic Capacity for College Students: Flexible Thinking and Communicating as Puppeteers, Community Partners, and Citizen-Leaders
College students face a complex world filled with pervasive social problems that require strong
knowledge bases, critical thinking abilities, and sustained engagement in civic life. This article details
key pedagogical practices for our innovative health puppetry program, in which undergraduate honors
students use puppets to share information about healthy eating, diabetes prevention, and active lifestyles with children and their families in community settings. We articulate a notion of “flexible thinking� as the ability to take on and perform new roles within the public/civic arena by seeing complex social problems from multiple perspectives and responding with creative solutions and engaged action. We look to the written reflections of our student puppeteers to share, in their own words, multiple ways their thinking and communication changed as they grew as puppeteers, community partners, and citizen-leaders. We also offer insights about promoting flexible thinking through in-depth service-learning
Structural Insight into KCNQ (Kv7) Channel Assembly and Channelopathy
SummaryKv7.x (KCNQ) voltage-gated potassium channels form the cardiac and auditory IKs current and the neuronal M-current. The five Kv7 subtypes have distinct assembly preferences encoded by a C-terminal cytoplasmic assembly domain, the A-domain Tail. Here, we present the high-resolution structure of the Kv7.4 A-domain Tail together with biochemical experiments that show that the domain is a self-assembling, parallel, four-stranded coiled coil. Structural analysis and biochemical studies indicate conservation of the coiled coil in all Kv7 subtypes and that a limited set of interactions encode assembly specificity determinants. Kv7 mutations have prominent roles in arrhythmias, deafness, and epilepsy. The structure together with biochemical data indicate that A-domain Tail arrhythmia mutations cluster on the solvent-accessible surface of the subunit interface at a likely site of action for modulatory proteins. Together, the data provide a framework for understanding Kv7 assembly specificity and the molecular basis of a distinct set of Kv7 channelopathies
Cost-effectiveness and value of information analysis of a low-friction environment following skin graft in patients with burn injury
Background
Patients with burn injuries may receive a skin graft to achieve healing in a timely manner. However, in around 7% of cases, the skin graft is lost (fails to attach to the wound site) and a re-grafting procedure is necessary. It has been hypothesised that low-friction (smooth, more slippery) bedding may reduce the risk of skin-graft loss. A before and after feasibility study comparing low-friction with standard bedding in skin-grafted patients was conducted in order to collect proof of concept data. The resulting relative risk on the primary outcome (number of patients with skin graft failure) for the non-randomised study provided no evidence of effect but had a large standard error. The aim of this study is to see if an appropriately powered randomised control trial would be worthwhile.
Methods
A probabilistic decision-analytic model was constructed to compare low-friction bedding to standard care in a population of burn patients who have undergone skin grafting. Results from the before and after study were used as model inputs. The sensitivity of results to bias in the relative risk of graft loss was conducted. Low-friction bedding is considered optimal if expected incremental net benefit (INB) is positive. Uncertainty is assessed using cost-effectiveness acceptability curves. Expected Value of Perfect Partial Information (EVPPI) provides an upper bound for the potential net health benefits of new research for given model input.
Results
At a willingness to pay threshold of £20,000 per QALY, INB = £151 (95% Credible Interval (CrI) −142 to 814), marginally favouring low-friction bedding but with high uncertainty (probability of being cost-effective 70.5%). Expected value of perfect information (EVPI) per patient was £20.29, which results in a population EVPI of £174,765 over a 10-year lifetime for the technology (based on 1000 patients per year who would benefit from the intervention). The parameter contributing most to the uncertainty was the inpatient care cost, i.e. information that could be obtained from the audit of practice and without an expensive trial. These findings were robust to a wide-range of assumptions about the potential bias due to the observational nature of the comparative evidence.
Conclusions
Our study results suggest that an RCT (randomised controlled trial) is unlikely to be worthwhile, but there may be value in a study to estimate the re-graft rates and associated costs in this population
Tests of pattern separation and pattern completion in humans - a systematic review
OBJECTIVE:
To systematically review the characteristics, validity and outcome measures of tasks that have been described in the literature as assessing pattern separation and pattern completion in humans.
METHODS:
Electronic databases were searched for articles. Parameters for task validity were obtained from two reviews that described optimal task design factors to evaluate pattern separation and pattern completion processes. These were that pattern separation should be tested during an encoding task using abstract, never-before-seen visual stimuli, and pattern completion during a retrieval task using partial cues; parametric alteration of the degree of interference of stimuli or degradation of cues should be used to generate a corresponding gradient in behavioral output; studies should explicitly identify the specific memory domain under investigation (sensory/perceptual, temporal, spatial, affect, response, or language) and account for the contribution of other potential attributes involved in performance of the task. A systematic, qualitative assessment of validity in relation to these parameters was performed, along with a review of general validity and task outcome measures.
RESULTS:
Sixty-two studies were included. The majority of studies investigated pattern separation and most tasks were performed on young, healthy adults. Pattern separation and pattern completion were most frequently tested during a retrieval task using familiar or recognizable visual stimuli and cues. Not all studies parametrically altered the degree of stimulus interference or cue degradation, or controlled for potential confounding factors.
CONCLUSION:
This review found evidence that some of the parameters for task validity have been followed in some human studies of pattern separation and pattern completion, but no study was judged to have adequately met all the parameters for task validity. The contribution of these parameters and other task design factors towards an optimal behavioral paradigm is discussed and recommendations for future research are made. This article is protected by copyright. All rights reserved
Emphasizing responder speed or accuracy modulates but does not abolish the distractor-induced quitting effect in visual search
Acknowledgements This research project was initially presented at the 2023 Australasian Experimental Psychology Conference (Lawrence et al., 2023c April 12–14). The authors would like to acknowledge the feedback and insights provided by Professor Allison Waters throughout the conceptualization and execution of this project. Funding This research was supported by a Griffith University New Researcher Grant awarded to RKL.Peer reviewedPublisher PD
Post-discharge care following acute kidney injury: quality improvement in primary care
BACKGROUND: Over the past decade, targeting acute kidney injury (AKI) has become a priority to improve patient safety and health outcomes. Illness complicated by AKI is common and is associated with adverse outcomes including high rates of unplanned hospital readmission. Through national patient safety directives, NHS England has mandated the implementation of an AKI clinical decision support system in hospitals. In order to improve care following AKI, hospitals have also been incentivised to improve discharge summaries and general practices are recommended to establish registers of people who have had an episode of illness complicated by AKI. However, to date, there is limited evidence surrounding the development and impact of interventions following AKI. DESIGN: We conducted a quality improvement project in primary care aiming to improve the management of patients following an episode of hospital care complicated by AKI. All 31 general practices within a single NHS Clinical Commissioning Group were incentivised by a locally commissioned service to engage in audit and feedback, education training and to develop an action plan at each practice to improve management of AKI. RESULTS: AKI coding in general practice increased from 28% of cases in 2015/2016 to 50% in 2017/2018. Coding of AKI was associated with significant improvements in downstream patient management in terms of conducting a medication review within 1 month of hospital discharge, monitoring kidney function within 3 months and providing written information about AKI to patients. However, there was no effect on unplanned hospitalisation and mortality. CONCLUSION: The findings suggest that the quality improvement intervention successfully engaged a primary care workforce in AKI-related care, but that a higher intensity intervention is likely to be required to improve health outcomes. Development of a real-time audit tool is necessary to better understand and minimise the impact of the high mortality rate following AKI
Black Phosphorus Degradation during Intercalation and Alloying in Batteries
Numerous layered materials are being recognized as promising candidates for high-performance alkali-ion battery anodes, but black phosphorus (BP) has received particular attention. This is due to its high specific capacity, due to a mixed alkali-ion storage mechanism (intercalation-alloying), and fast alkali-ion transport within its layers. Unfortunately, BP based batteries are also commonly associated with serious irreversible losses and poor cycling stability. This is known to be linked to alloying, but there is little experimental evidence of the morphological, mechanical, or chemical changes that BP undergoes in operational cells and thus little understanding of the factors that must be mitigated to optimize performance. Here the degradation mechanisms of BP alkali-ion battery anodes are revealed through operando electrochemical atomic force microscopy (EC-AFM) and ex situ spectroscopy. Among other phenomena, BP is observed to wrinkle and deform during intercalation but suffers from complete structural breakdown upon alloying. The solid electrolyte interphase (SEI) is also found to be unstable, nucleating at defects before spreading across the basal planes but then disintegrating upon desodiation, even above alloying potentials. By directly linking these localized phenomena with the whole-cell performance, we can now engineer stabilizing protocols for next-generation high-capacity alkali-ion batteries
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