522 research outputs found

    Complexity Bounds for Ordinal-Based Termination

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    `What more than its truth do we know if we have a proof of a theorem in a given formal system?' We examine Kreisel's question in the particular context of program termination proofs, with an eye to deriving complexity bounds on program running times. Our main tool for this are length function theorems, which provide complexity bounds on the use of well quasi orders. We illustrate how to prove such theorems in the simple yet until now untreated case of ordinals. We show how to apply this new theorem to derive complexity bounds on programs when they are proven to terminate thanks to a ranking function into some ordinal.Comment: Invited talk at the 8th International Workshop on Reachability Problems (RP 2014, 22-24 September 2014, Oxford

    Up and down the number line: modelling collaboration in contrasting school and home environments

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    This paper is concerned with user modelling issues such as adaptive educational environments, adaptive information retrieval, and support for collaboration. The HomeWork project is examining the use of learner modelling strategies within both school and home environments for young children aged 5 – 7 years. The learning experience within the home context can vary considerably from school especially for very young learners, and this project focuses on the use of modelling which can take into account the informality and potentially contrasting learning styles experienced within the home and school

    Location, Location, Location: Is Membrane Partitioning Everything When It Comes to Innate Immune Activation?

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    In the last twenty years, the general view of the plasma membrane has changed from a homogeneous arrangement of lipids to a mosaic of microdomains. It is currently thought that islands of highly ordered saturated lipids and cholesterol, which are laterally mobile, exist in the plane of the plasma membrane. Lipid rafts are thought to provide a means to explain the spatial segregation of certain signalling pathways emanating from the cell surface. They seem to provide the necessary microenvironment in order for certain specialised signalling events to take place, such as the innate immune recognition. The innate immune system seems to employ germ-lined encoded receptors, called pattern recognition receptors (PRRs), in order to detect pathogens. One family of such receptors are the Toll-like receptors (TLRs), which are the central “sensing” apparatus of the innate immune system. In recent years, it has become apparent that TLRs are recruited into membrane microdomains in response to ligands. These nanoscale assemblies of sphingolipid, cholesterol, and TLRs stabilize and coalesce, forming signalling platforms, which transduce signals that lead to innate immune activation. In the current paper, we will investigate all past and current literature concerning recruitment of extracellular and intracellular TLRs into lipid rafts and how this membrane organization modulates innate immune responses

    What is the source level of pile-driving noise in water?

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    To meet the growing demand for carbon-free energy sources, the European Union (EU) has ambitious plans to increase its capacity for generation of offshore wind power. The United Kingdom and The Netherlands, for example, plan to increase their offshore power-generating capacity to 33 and 6 GW, respectively, by the year 2020. Assuming that this power is generated entirely by wind and that a single wind turbine can generate up to 10 MW, at least 3,900 offshore turbines would be required by these two states alone to achieve this goal. A popular turbine construction method known as “pile driving” involves the use of hammering a steel cylinder (a “monopile”) into the seabed. A concern has arisen for the possible effect on mammals (Southall et al. 2007) and fish (Popper and Hastings 2009) of the sound produced by the succession of hammer impacts required to sink the pile to its required depth (tens of meters)

    Generating socially appropriate tutorial dialog

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    Analysis of student-tutor coaching dialogs suggest that good human tutors attend to and attempt to influence the motivational state of learners. Moreover, they are sensitive to the social face of the learner, and seek to mitigate the potential face threat of their comments. This paper describes a dialog generator for pedagogical agents that takes motivation and face threat factors into account. This enables the agent to interact with learners in a socially appropriate fashion, and foster intrinsic motivation on the part of the learner, which in turn may lead to more positive learner affective states

    Caregiver strain on informal caregivers when providing care for older patients undergoing major abdominal surgery:A longitudinal prospective cohort study

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    Background:  Health-care systems nowadays rely on complementary patient care by informal caregivers. The need for, and burden on, informal caregivers will likely increase in the upcoming years. This study aimed to examine the burden on caregivers when providing care for elderly patients undergoing major abdominal surgery. Methods:  A single-centre longitudinal cohort study was conducted between November 2015 and June 2018 in the Amphia hospital in Breda, the Netherlands. Patients aged 70+ undergoing elective surgery for colorectal carcinoma (CRC) or an abdominal aortic aneurysm (AAA) were included in this study. Informal caregiver burden was assessed and compared over time using the Caregiver Strain Index (CSI) at the outpatient clinic visit, at discharge, 2 weeks post-discharge and after 6 and 12 months. The effects of patient- and caregiver-related factors on the experienced caregiver strain were examined. Results: CSI scores of 248 caregivers were significantly increased at discharge (3.5 vs 2.6; p < 0.001) and 2 weeks post-discharge (3.3 vs 2.6; p < 0.001). After 12 months, scores dropped below baseline scores (1.8 vs 2.6; p = 0.012). The highest strain was observed 2 weeks post-discharge for AAA patients and at discharge for CRC patients. Older age, physical or cognitive impairment and burden of comorbidity were associated with an increased caregiver strain at baseline. Type of surgery was independently associated with the change in mean CSI scores over time; a bigger change in caregiver burden is observed after open surgery. Conclusion:  In the early postoperative period, perceived caregiver strain was significantly increased. Psychological support for caregivers may be advisable, with timing of this support depending on diagnosis and patient-related factors. Trial registration: This manuscript was retrospectively registered on 05-04-2016 in the Netherlands Trial Register (NTR5932). http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=593

    Loss of Ptpn11 (Shp2) drives satellite cells into quiescence

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    The equilibrium between proliferation and quiescence of myogenic progenitor and stem cells is tightly regulated to ensure appropriate skeletal muscle growth and repair. The non-receptor tyrosine phosphatase Ptpn11 (Shp2) is an important transducer of growth factor and cytokine signals. Here we combined complex genetic analyses, biochemical studies and pharmacological interference to demonstrate a central role of Ptpn11 in postnatal myogenesis of mice. Loss of Ptpn11 drove muscle stem cells out of the proliferative and into a resting state during muscle growth. This Ptpn11 function was observed in postnatal but not fetal myogenic stem cells. Furthermore, muscle repair was severely perturbed when Ptpn11 was ablated in stem cells due to a deficit in stem cell proliferation and survival. Our data demonstrate a molecular difference in the control of cell cycle withdrawal in fetal and postnatal myogenic stem cells, and assign to Ptpn11 signaling a key function in satellite cell activity

    An internet of things system for urban flood monitoring and short-term flood forecasting in Colima, Mexico

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    Urban flooding is one of the major issues in many parts of the world and its management often challenging. Here we present Internet of Things (IoT) approach for monitoring urban flooding in the City of Colima, Mexico. A network of water level and weather sensors have been developed along with a web-based data platform integrated with IoT techniques to retrieve data using 3G/4G and Wi-Fi networks. The developed architecture uses the Message Queuing Telemetry Transport protocol to send real-time data packages from fixed nodes to a server that stores retrieved data in a non-relational database. Data can be accessed and displayed through different queries and graphical representations, allowing future use in flood analysis and prediction. Additionally, machine learning algorithms are integrated into the system for short-range water level predictions at different nodes of the network
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