344 research outputs found

    Article Students' Understanding of External Representations of the Potassium Ion Channel Protein Part II: Structure-Function Relationships and Fragmented Knowledge*

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    Research that has focused on external representations in biochemistry has uncovered student difficulties in comprehending and interpreting external representations. This study focuses on students' understanding of three external representations (ribbon diagram, wireframe, and hydrophobic/hydrophilic) of the potassium ion channel protein. Analysis of the interview data demonstrates that students were able to use the ribbon structures and polarity of the cell membrane to help support claims about the protein's orientation and interactions within the cell membrane. Students expressed fragmented understandings of the interactions between the potassium ion and the aqueous solution outside/inside of the cell membrane. Suggestions for instruction are to probe student understanding to help students activate prior knowledge and to help them build a more connected set of concepts pertaining to protein structure and function. Keywords: Visual literacy, tertiary education, scholarship of teaching and learning. Biochemistry students must interpret and use external representations to understand large, complex biochemical macromolecules. Whereas our first article in this two-part series focused on how students interpret three types of external representations of the potassium ion channel, this article describes how students use external representations to support their claims about channel's structure and function. Schö nborn and Anderson [1] have identified factors that affect students' ability to interpret and use external representations in biochemistry, including: • Ability to make sense of and read the external representation • Ability to select and retrieve conceptual knowledge of relevance to the external representation • Understanding of the concepts of relevance to the external representation Schö nborn and Anderson Sampling and Participants Maximum variation sampling methods were used to capture the central themes that cut across study participants from a variety of biochemistry courses in the chemistry and biochemis

    Honesty mediates the relationship between serotonin and reaction to unfairness

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    How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness

    An Effective Capacity Estimation Scheme in IEEE802.11-based Ad Hoc Networks

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    ABSTRACT Capacity estimation is a key component of any admission control scheme required to support quality of service provision in mobile ad hoc networks. A range of schemes have been previously proposed to estimate residual capacity that is derived from window-based measurements of channel estimation. In this paper a simple and improved mechanism to estimate residual capacity in IEEE802.11-based ad hoc networks is presented. The scheme proposes the use of a 'forgiveness' factor to weight these previous measurements and is shown through simulation-based evaluation to provide accurate utilizations estimation and improved residual capacity based admission control

    Does an interactive trust-enhanced electronic consent improve patient experiences when asked to share their health records for research? A randomized trial

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    Objective In the context of patient broad consent for future research uses of their identifiable health record data, we compare the effectiveness of interactive trust-enhanced e-consent, interactive-only e-consent, and standard e-consent (no interactivity, no trust enhancement). Materials and Methods A randomized trial was conducted involving adult participants making a scheduled primary care visit. Participants were randomized into 1 of the 3 e-consent conditions. Primary outcomes were patient-reported satisfaction with and subjective understanding of the e-consent. Secondary outcomes were objective knowledge, perceived voluntariness, trust in medical researchers, consent decision, and time spent using the application. Outcomes were assessed immediately after use of the e-consent and at 1-week follow-up. Results Across all conditions, participants (N = 734) reported moderate-to-high satisfaction with consent (mean 4.3 of 5) and subjective understanding (79.1 of 100). Over 94% agreed to share their health record data. No statistically significant differences in outcomes were observed between conditions. Irrespective of condition, black participants and those with lower education reported lower satisfaction, subjective understanding, knowledge, perceived voluntariness, and trust in medical researchers, as well as spent more time consenting. Conclusions A large majority of patients were willing to share their identifiable health records for research, and they reported positive consent experiences. However, incorporating optional additional information and messages designed to enhance trust in the research process did not improve consent experiences. To improve poorer consent experiences of racial and ethnic minority participants and those with lower education, other novel consent technologies and processes may be valuable

    Prospects for improving the representation of coastal and shelf seas in global ocean models

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    Accurately representing coastal and shelf seas in global ocean models represents one of the grand challenges of Earth system science. They are regions of immense societal importance through the goods and services they provide, hazards they pose and their role in global-scale processes and cycles, e.g. carbon fluxes and dense water formation. However, they are poorly represented in the current generation of global ocean models. In this contribution, we aim to briefly characterise the problem, and then to identify the important physical processes, and their scales, needed to address this issue in the context of the options available to resolve these scales globally and the evolving computational landscape. We find barotropic and topographic scales are well resolved by the current state-of-the-art model resolutions, e.g. nominal 1∕12°, and still reasonably well resolved at 1∕4°; here, the focus is on process representation. We identify tides, vertical coordinates, river inflows and mixing schemes as four areas where modelling approaches can readily be transferred from regional to global modelling with substantial benefit. In terms of finer-scale processes, we find that a 1∕12° global model resolves the first baroclinic Rossby radius for only  ∼ 8% of regions  < 500m deep, but this increases to  ∼ 70% for a 1∕72° model, so resolving scales globally requires substantially finer resolution than the current state of the art. We quantify the benefit of improved resolution and process representation using 1∕12° global- and basin-scale northern North Atlantic nucleus for a European model of the ocean (NEMO) simulations; the latter includes tides and a k-ε vertical mixing scheme. These are compared with global stratification observations and 19 models from CMIP5. In terms of correlation and basin-wide rms error, the high-resolution models outperform all these CMIP5 models. The model with tides shows improved seasonal cycles compared to the high-resolution model without tides. The benefits of resolution are particularly apparent in eastern boundary upwelling zones. To explore the balance between the size of a globally refined model and that of multiscale modelling options (e.g. finite element, finite volume or a two-way nesting approach), we consider a simple scale analysis and a conceptual grid refining approach. We put this analysis in the context of evolving computer systems, discussing model turnaround time, scalability and resource costs. Using a simple cost model compared to a reference configuration (taken to be a 1∕4° global model in 2011) and the increasing performance of the UK Research Councils' computer facility, we estimate an unstructured mesh multiscale approach, resolving process scales down to 1.5km, would use a comparable share of the computer resource by 2021, the two-way nested multiscale approach by 2022, and a 1∕72° global model by 2026. However, we also note that a 1∕12° global model would not have a comparable computational cost to a 1° global model in 2017 until 2027. Hence, we conclude that for computationally expensive models (e.g. for oceanographic research or operational oceanography), resolving scales to  ∼ 1.5km would be routinely practical in about a decade given substantial effort on numerical and computational development. For complex Earth system models, this extends to about 2 decades, suggesting the focus here needs to be on improved process parameterisation to meet these challenges

    Projected sea level rise and changes in extreme storm surge and wave events during the 21st century in the region of Singapore

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    Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea-level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time mean sea level were evaluated using the process-based climate model data and methods presented in the IPCC AR5. Regional surge and wave solutions extending from 1980 to 2100 were generated using ~ 12 km resolution surge (Nucleus for European Modelling of the Ocean – NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled (~ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980–2010, enabling a quantitative assessment of model skill. Simulated historical sea surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the RCP 4.5 (8.5) scenarios respectively. Trends in surge and significant wave height 2 year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the dominant signal of change to the projected inundation risk for Singapore during the 21st century. We note that the largest recorded surge residual in the Singapore Strait of ~ 84 cm lies between the central and upper estimates of sea level rise by 2100, highlighting the vulnerability of the region

    Clinical expert guidelines for the management of cough in lung cancer: report of a UK task group on cough

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    Background Cough is a common and distressing symptom in lung cancer patients. The clinical management of cough in lung cancer patients is suboptimal with limited high quality research evidence available. The aim of the present paper is to present a clinical guideline developed in the UK through scrutiny of the literature and expert opinion, in order to aid decision making in clinicians and highlight good practice. Methods Two systematic reviews, one focusing on the management of cough in respiratory illness and one Cochrane review specifically on cancer, were conducted. Also, data from reviews, phase II trials and case studies were synthesized. A panel of experts in the field was also convened in an expert consensus meeting to make sense of the data and make clinical propositions. Results A pyramid of cough management was developed, starting with the treatment of reversible causes of cough/specific pathology. Initial cough management should focus on peripherally acting and intermittent treatment; more resistant symptoms require the addition of (or replacement by) centrally acting and continuous treatment. The pyramid for the symptomatic management starts from the simpler and most practical regimens (demulcents, simple linctus) to weak opioids to morphine and methadone before considering less well-researched and experimental approaches. Conclusion The clinical guidelines presented aim to provide a sensible clinical approach to the management of cough in lung cancer. High quality research in this field is urgently required to provide more evidence-based recommendations

    Human activity and climate variability project: annual report 2002.

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    This project aims to utilise nuclear techniques to investigate evidence of human activity and climate variability in the Asia Australasian regions. It was originally designed to run over three years, commencing July 1999, with three parallel research tasks: Task 1: Past -- Natural archives of human activity and climate variability; Task 2: Present -- Characterisation of the global atmosphere using radon and fine particles; Task 3: Future -- Climate modelling: evaluation and improvement; Main project objectives -- To determine what proportions of changes in natural archives are due to human activity and climate variability; -- To contribute to the understanding of the impact of human induced and natural aerosols in the East Asian region on climate through analysis and sourcing of fine particles and characterisation of air samples using radon concentrations; -- To contribute to the improvement of land surface parameterisation schemes and investigate the potential to use isotopes to improve global climate models and thus improve our understanding of future climate. Significant project outcomes -- An improved understanding of natural and anthropogenic factors influencing change in our environment; -- A better understanding of the role of aerosols in climate forcing in the Asian region, leading to improved ability to predict climate change; -- An improved understanding of long term changes in the concentrations of trace species in the atmosphere on a regional and a global basis and their use in model evaluation; -- Improved understanding of the impact of different land-surface schemes on simulations by atmospheric models. The next two years of the project Our new and extended projects efforts include: 1) Aligning ourselves with the recently developed mission of the IGBP/PAGES research program 'Human Interactions on Terrestrial Ecosystems' and co-ordinating the Australasian research effort. Further research will focus on: (1) How widespread and reliable are evidence of major climatic events, such as storms and El Nino/La Nina cycles, in natural archives? This would require more natural archives to be examined from northern Australia and also records to be obtained from southern Australia. (2) The spatial extent of mining related pollutants, in the form of aerosol particles, which is of importance to managing the waste in the future. A combination of aerosol and archival studies will address this issue. In Summary: To achieve these extended goals we successfully gained another two years of further support for our project
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