296 research outputs found

    Nano-scale reservoir computing

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    This work describes preliminary steps towards nano-scale reservoir computing using quantum dots. Our research has focused on the development of an accumulator-based sensing system that reacts to changes in the environment, as well as the development of a software simulation. The investigated systems generate nonlinear responses to inputs that make them suitable for a physical implementation of a neural network. This development will enable miniaturisation of the neurons to the molecular level, leading to a range of applications including monitoring of changes in materials or structures. The system is based around the optical properties of quantum dots. The paper will report on experimental work on systems using Cadmium Selenide (CdSe) quantum dots and on the various methods to render the systems sensitive to pH, redox potential or specific ion concentration. Once the quantum dot-based systems are rendered sensitive to these triggers they can provide a distributed array that can monitor and transmit information on changes within the material.Comment: 8 pages, 9 figures, accepted for publication in Nano Communication Networks, http://www.journals.elsevier.com/nano-communication-networks/. An earlier version was presented at the 3rd IEEE International Workshop on Molecular and Nanoscale Communications (IEEE MoNaCom 2013

    Designing an Articulation-Agreement Database for the College of Science and Engineering and Technology Advising Center

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    During their academic careers, some college students transfer to different universities. To allow students to transfer seamlessly to other colleges, advisors at Minnesota universities create articulation agreements that list the classes that transfer between two universities. To use these documents, students and advisors must search through binders to find the correct articulation agreement and then manually review it. This is a time-consuming process for both students and advisors. To make this information more accessible, we created a web-based database that instantly produces a list of equivalent classes for majors offered at Minnesota St ate University, Mankato (MSU) and other Minnesota universities. We designed the system for majors in the College of Science and Engineering and Technology (CSET); however, the system can be expanded to include all MSU majors. To design this system, we used a rapid application development strategy that emphasized using prototypes to develop and to refine the system’s functions and user interfaces. The primary users include CSET advisors, MSU faculty advisors, and transfer students. For advisors, the database provides fast access to data, and a reliable, centralized location to store the articulation agreements. These features allow advisors to spend less time searching for information, and more time working with students. Transfer students also benefit because they can access up-to-date articulation agreements at their convenience

    Modelling the Raft Distributed Consensus Protocol in mCRL2

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    The consensus problem is a fundamental problem in distributed systems. It involves a set of actors, or entities, that need to agree on some values or decisions. The Raft algorithm is a solution to the consensus problem that has gained widespread popularity as an easy-to-understand and implement alternative to Lamport's Paxos algorithm. In this paper we discuss a formalisation of the Raft algorithm and its associated correctness properties in the mCRL2 specification language.Comment: In Proceedings MARS 2024, arXiv:2403.1786

    Tracking Residual-Yolk Energy in Dormant Hatchling Turtles

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    Hatchling painted turtles (Chrysemys picta) spend their first winter inside natal nests without food and must rely on maternally derived energy in the form of residual yolk for up to nine months. In this study, we take a closer look at the use and movement of residual-yolk energy during the first 33 weeks (~8 mo.) after hatching by measuring changes in mass, lipid content, & protein content of yolk, liver, small intestine, and carcass. Our data showed a significant decrease in yolk mass by 64% and significant increases in carcass & liver masses of 9% & 16%, respectively, during the first 2 weeks after hatching. Yolk mass was further depleted to 17% at week 4, and did not significantly decrease further for the remaining 29 weeks. These results suggest that energy is transferred from residual yolk to somatic storage soon after hatching, and well before hibernation begins. We suggest that a low-temperature-induced down regulation of gut function that renders residual-yolk energy inaccessible during hibernation necessitates digestion and storage of residual-yolk energy soon after hatching when temperatures inside the nest are still high. That strategy may be used despite the net energy cost of digesting, storing, and later mobilizing that residual-yolk-derived energy. We are currently measuring triglyceride & protein contents of the aforementioned body parts to better track the use and movement of energy in the hatchlings

    How to check a simulation study

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    Simulation studies are powerful tools in epidemiology and biostatistics, but they can be hard to conduct successfully. Sometimes unexpected results are obtained. We offer advice on how to check a simulation study when this occurs, and how to design and conduct the study to give results that are easier to check. Simulation studies should be designed to include some settings in which answers are already known. They should be coded in stages, with data-generating mechanisms checked before simulated data are analysed. Results should be explored carefully, with scatterplots of standard error estimates against point estimates surprisingly powerful tools. Failed estimation and outlying estimates should be identified and dealt with by changing data-generating mechanisms or coding realistic hybrid analysis procedures. Finally, we give a series of ideas that have been useful to us in the past for checking unexpected results. Following our advice may help to prevent errors and to improve the quality of published simulation studies

    Ethnic Differences in the Prevalence of Type 2 Diabetes Diagnoses in the UK: Cross-Sectional Analysis of the Health Improvement Network Primary Care Database.

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    AIMS/HYPOTHESIS: Type 2 diabetes mellitus is associated with high levels of disease burden, including increased mortality risk and significant long-term morbidity. The prevalence of diabetes differs substantially among ethnic groups. We examined the prevalence of type 2 diabetes diagnoses in the UK primary care setting. METHODS: We analysed data from 404,318 individuals in The Health Improvement Network database, aged 0-99 years and permanently registered with general practices in London. The association between ethnicity and the prevalence of type 2 diabetes diagnoses in 2013 was estimated using a logistic regression model, adjusting for effect of age group, sex, and social deprivation. A multiple imputation approach utilising population-level information about ethnicity from the UK census was used for imputing missing data. RESULTS: Compared with those of White ethnicity (5.04%, 95% CI 4.95 to 5.13), the crude percentage prevalence of type 2 diabetes was higher in the Asian (7.69%, 95% CI 7.46 to 7.92) and Black (5.58%, 95% CI 5.35 to 5.81) ethnic groups, while lower in the Mixed/Other group (3.42%, 95% CI 3.19 to 3.66). After adjusting for differences in age group, sex, and social deprivation, all minority ethnic groups were more likely to have a diagnosis of type 2 diabetes compared with the White group (OR Asian versus White 2.36, 95% CI 2.26 to 2.47; OR Black versus White 1.65, 95% CI 1.56 to 1.73; OR Mixed/Other versus White 1.17, 95% CI 1.08 to 1.27). CONCLUSION: The prevalence of type 2 diabetes was higher in the Asian and Black ethnic groups, compared with the White group. Accurate estimates of ethnic prevalence of type 2 diabetes based on large datasets are important for facilitating appropriate allocation of public health resources, and for allowing population-level research to be undertaken examining disease trajectories among minority ethnic groups, that might help reduce inequalities

    Cost-Effectiveness of Propofol (Diprivan) Versus Inhalational Anesthetics to Maintain General Anesthesia in Noncardiac Surgery in the United States.

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    Abstract Objectives It is not known whether using propofol total intravenous anaesthesia (TIVA) to reduce incidence of postoperative nausea and vomiting (PONV) is cost-effective. We assessed the economic impact of propofol TIVA versus inhalational anesthesia in adult patients for ambulatory and inpatient procedures relevant to the US healthcare system. Methods Two models simulate individual patient pathways through inpatient and ambulatory surgery with propofol TIVA or inhalational anesthesia with economic inputs from studies on adult surgical US patients. Efficacy inputs were obtained from a meta-analysis of randomized controlled trials. Probabilistic and deterministic sensitivity analyses assessed the robustness of the model estimates. Results Lower PONV rate, shorter stay in the post-anesthesia care unit, and reduced need for rescue antiemetics offset the higher costs for anesthetics, analgesics, and muscle relaxants with propofol TIVA and reduced cost by 11.41 ± 10.73 USD per patient in the inpatient model and 11.25 ± 9.81 USD in the ambulatory patient model. Sensitivity analyses demonstrated strong robustness of the results. Conclusions Maintenance of general anesthesia with propofol was cost-saving compared to inhalational anesthesia in both inpatient and ambulatory surgical settings in the United States. These economic results support current guideline recommendations, which endorse propofol TIVA to reduce PONV risk and enhance postoperative recovery

    Agroforestry - The Most Resilient Farming System for the Hilly Northwest of Vietnam

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    Over 94% of the land of northwestern Vietnam is classified as sloping. Population growth has exerted pressure on local natural resources, with agricultural expansion on steep slopes resulting in forest degradation, landscape fragmentation and severe environmental consequences. Efforts to restore forest ecosystems have been made by the government, however, as the livelihoods of 80% of the population depend on agriculture, the reconversion of land to forest has proven to be an inappropriate solution. Agroforestry offers a potentially sustainable land-use solution, which could re-establish forests, restore ecosystem services, and stabilize local livelihoods. In this paper, we assess the potential of agroforestry development in the region based on the results of two interrelated surveys conducted in 21 representative villages in six districts of three northwestern provinces: 1) a farming system diagnosis implemented in 17 representative villages; and 2) an agroforestry adoption survey with 210 households practising agroforestry in 14 villages. The analysis was strengthened by four years’ experience in implementing an extensive agroforestry project in the region. The studies focussed on assessing key benefits and constraints of existing farming systems, including agroforestry practices, adopted by farmers and identifying the potential for agroforestry development in the region. The results showed that the dominant farming system in the north-western provinces was monoculture of staple crops on slopes, which provided relatively low economic returns. Soil erosion, land degradation, and water shortages resultant from intensive farming practices were the most significant environmental issues in the area. Tree-based farming systems were rare and mostly a result of spontaneous adoption by farmers. Given the mountainous landscape and the need for soil stabilization, agroforestry was seen by farmers as a viable approach. Improving the existing and adopting new, integrated agroforestry systems were identified as viable ways toward sustainable livelihoods in Northwestern Vietnam

    The marginality principle revisited: Should “higher-order” terms always be accompanied by “lower-order” terms in regression analyses?

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    The marginality principle guides analysts to avoid omitting lower-order terms from models in which higher-order terms are included as covariates. Lower-order terms are viewed as “marginal” to higher-order terms. We consider how this principle applies to three cases: regression models that may include the ratio of two measured variables; polynomial transformations of a measured variable; and factorial arrangements of defined interventions. For each case, we show that which terms or transformations are considered to be lower-order, and therefore marginal, depends on the scale of measurement, which is frequently arbitrary. Understanding the implications of this point leads to an intuitive understanding of the curse of dimensionality. We conclude that the marginality principle may be useful to analysts in some specific cases but caution against invoking it as a context-free recipe

    Identifying factors for job motivation of rural health workers in North Viet Nam

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    BACKGROUND: In Viet Nam, most of the public health staff (84%) currently works in rural areas, where 80% of the people live. To provide good quality health care services, it is important to develop strategies influencing staff motivation for better performance. METHOD: An exploratory qualitative research was carried out among health workers in two provinces in North Viet Nam so as to identify entry points for developing strategies that improve staff performance in rural areas. The study aimed to determine the major motivating factors and it is the first in Viet Nam that looks at health workers' job perception and motivation. Apart from health workers, managers at national and at provincial level were interviewed as well as some community representatives. RESULTS: The study showed that motivation is influenced by both financial and non-financial incentives. The main motivating factors for health workers were appreciation by managers, colleagues and the community, a stable job and income and training. The main discouraging factors were related to low salaries and difficult working conditions. CONCLUSION: Activities associated with appreciation such as performance management are currently not optimally implemented, as health workers perceive supervision as control, selection for training as unclear and unequal, and performance appraisal as not useful. The kind of non-financial incentives identified should be taken into consideration when developing HRM strategies. Areas for further studies are identified
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