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  • 1158101.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Optimal ball pitchingArticle in journal (Other academic)
  • 1158102.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Optimal control of a ball pitching robot2012In: 2012 17TH INTERNATIONAL CONFERENCE ON METHODS AND MODELS IN AUTOMATION AND ROBOTICS (MMAR), 2012, p. 456-456Conference paper (Refereed)
    Abstract [en]

    We study a two-link pitching robot, with an active gripping mechanism and aim to make it throw a ball as far as possible. The two links are connected at the elbow joint by a linear torsional spring. The gripping mechanism is able to hold a ball and release it at any specified time. The two-link pitching robot is connected to a motor shaft at the shoulder joint by a non-linear torsional spring. The shoulder joint is held fixed at the origin of the coordinate system. The configuration of the arm and the motor shaft is illustrated in Figure 1 and described by the angels q1 and qm, measured with respect to the horizontal axis, respectively, whereas q2 denote the angle change between the arm and forearm at the elbow joint.

  • 1158103.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    State constrained optimal control of a ball pitching robot2013In: Mechanism and machine theory, ISSN 0094-114X, E-ISSN 1873-3999, Vol. 69, p. 337-349Article in journal (Refereed)
    Abstract [en]

    We present a method for offline optimal control of a two-link ball pitching robot with the aim of throwing a ball as far as possible. The pitching robot is connected to a motor via a non-linear torsional spring at the shoulder joint. The elbow joint is passive and loaded with a linear torsional spring. We model the system based on an Euler–Lagrange formulation. Constraints on the motor torque and power as well as the angular velocity of the motor shaft are included in the model. By using an interior point method with gradients supplied by a discrete adjoint method, we numerically solve the resulting constrained control problem of finding the optimal piecewise constant motor torque profile and release position. Numerical experiments illustrate the effectiveness of our strategy as well as the effect of the constraints on the objective. In our experiments, the optimal motor torque gives rise to motions comprising an initial backswing; a transition, where the elbow spring accumulates potential energy; and finally a fast acceleration phase leading up the ball release.

  • 1158104.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Anisotropic Topology Optimization of a Reactive Muffler with a Perforated PipeArticle in journal (Other academic)
  • 1158105.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Interior layout topology optimization of a reactive muffler2016In: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 53, no 4, p. 645-656Article in journal (Refereed)
    Abstract [en]

    This article presents a material distribution method that is tailored to the interior design of reactive mufflers. Such devices are typically acoustically small, except in the length direction, and their interior consists of a combination of pipes, expansions, contractions, and Helmholtz resonators. In order to design the interior layout using material distribution optimization, it is necessary to be able to resolve thin sound-hard materials as well as thin sheets with a given acoustic impedance, such as perforated plates, and manage small channels to Helmholtz resonators. We develop a method that uses an anisotropic design filter in combination with a fine mesh in order to control the minimum thickness separately in different directions. A two-stage post processing procedure is used to control openings to resonators, and embedded thin impedance surfaces are modeled by a mortar-element method. Numerical results demonstrate that the approach can produce mufflers with high transmission loss for a broad range of frequencies. The optimized mufflers include components that resemble combinations of expansion chambers, cylindrical pipes, and Helmholtz resonators.

  • 1158106.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Layout optimization of thin sound-hard material to improve the far-field directivity properties of an acoustic horn2017In: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 55, no 3, p. 795-808Article in journal (Refereed)
    Abstract [en]

    To improve the far-field directivity properties of a given mid-range acoustic horn, previously designed by shape optimization to exhibit almost ideal transmission properties in the frequency range 1.6–9.05 kHz, we apply layout optimization of thin sound-hard material in the interior of the horn. The purpose of the optimization is to place scattering material to prevent the sound intensity to increasingly be concentrated, with increasing frequency, along the horn axis. Absence or presence of thin sound-hard material is modeled by an equivalent surface transmission impedance, and the optimization algorithm determines the distribution of air or sound-hard material along a “ground structure” in the form of a grid inside the horn. The surface impedance is numerically handled using a newly developed finite-element formulation that allows exact enforcement of a vanishing impedance, corresponding to air, which would not be possible using a standard formulation. Horns provided with the optimized scatterers show a much improved angular coverage, compared to the initial configuration, with beam widths that exceed 60 ∘ uniformly over the operational frequency range, without destroying the good transmission properties of the initial horn.

  • 1158107.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hansbo, Peter
    Larson, Mats G.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    A Nitsche-type Method for Helmholtz Equation with an Embedded Acoustically Permeable Interface2016In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 304, p. 479-500Article in journal (Refereed)
    Abstract [en]

    We propose a new finite element method for Helmholtz equation in the situation where an acoustically permeable interface is embedded in the computational domain. A variant of Nitsche's method, different from the standard one, weakly enforces the impedance conditions for transmission through the interface. As opposed to a standard finite-element discretization of the problem, our method seamlessly handles a complex-valued impedance function Z that is allowed to vanish. In the case of a vanishing impedance, the proposed method reduces to the classic Nitsche method to weakly enforce continuity over the interface. We show stability of the method, in terms of a discrete Gårding inequality, for a quite general class of surface impedance functions, provided that possible surface waves are sufficiently resolved by the mesh. Moreover, we prove an a priori error estimate under the assumption that the absolute value of the impedance is bounded away from zero almost everywhere. Numerical experiments illustrate the performance of the method for a number of test cases in 2D and 3D with different interface conditions. 

  • 1158108.
    Yedeg, Esubalewe Lakie
    et al.
    Umeå University.
    Wadbro, Eddie
    Umeå University.
    Hansbo, Peter
    Jönköping University, School of Engineering, JTH, Product Development. Jönköping University, School of Engineering, JTH. Research area Product Development - Simulation and Optimization.
    Larson, Mats G.
    Umeå University.
    Berggren, Martin
    Umeå University.
    A Nitsche-type method for Helmholtz equation with an embedded acoustically permeable interface2016In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 304, p. 479-500Article in journal (Refereed)
    Abstract [en]

    We propose a new finite element method for Helmholtz equation in the situation where an acoustically permeable interface is embedded in the computational domain. A variant of Nitsche’s method, different from the standard one, weakly enforces the impedance conditions for transmission through the interface. As opposed to a standard finite-element discretization of the problem, our method seamlessly handles a complex-valued impedance function Z that is allowed to vanish. In the case of a vanishing impedance, the proposed method reduces to the classic Nitsche method to weakly enforce continuity over the interface. We show stability of the method, in terms of a discrete Gårding inequality, for a quite general class of surface impedance functions, provided that possible surface waves are sufficiently resolved by the mesh. Moreover, we prove an a priori error estimate under the assumption that the absolute value of the impedance is bounded away from zero almost everywhere. Numerical experiments illustrate the performance of the method for a number of test cases in 2D and 3D with different interface conditions.

  • 1158109.
    Yederulh, Hulumtaye Kefyalew
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Settlement calculation for lime/cement column improved clay: Analytical and numerical analyses related to a case study2018Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The dry deep mixing method is widely used to improve a soft clay soil to increase the shear strength as well as to reduce the time for consolidation. It is a mechanical mixing process that makes parts of the soil stiffer than its original strength. It is mainly applicable to soft clay or peat soil.

     

    In this master thesis, the objective was set to perform a comparative analysis on the prediction of the settlements of a clay soil improved by lime/cement columns (LCC). The theoretical settlement predictions were made using two analytical and numerical modeling. A case study was carried out on a part of Stockholm bypass project where LCC was applied to improve soft clay for a foundation of a concrete trough. Field measurements of the vertical deformation of the improved soil were performed using settlement plates to compare the analytical and numerical results.

    The first analytical method was performed based on the recommendation of TK Geo 13 (2013) while the second method was performed based on the concept of a composite ground. In the case of the numerical method, FEA was performed using 2D plane strain model in Plaxis simulation. The performance of the geometry and combined matching models were investigated to convert the axisymmetric to plane strain model. The variation in stiffness of the columns were taken into consideration by applying two stiffness values 30 and 33 MPa for the upper and lower half of the column respectively. A preload of 58 kPa was applied on the improved clay soil to simulate the time-dependent consolidation settlement due to the stress addition.

    A comparison was carried out between the results obtained from the analysis and a field measurement. The two analytical methods produced a better agreement with the field measurement regarding long-term consolidation settlement and a reasonable agreement concerning the rate of consolidation. The numerical analysis showed a good agreement with the benchmark concerning both the long-term consolidation settlement as well as the rate of consolidation. The geometry matching model gave a reasonable result regarding correctness of the result compared with the combined matching. Based on the results obtained in this study, the numerical methods had a better agreement with the measurements.

  • 1158110.
    Yedollahi, Ellham
    et al.
    Mälardalen University, School of Education, Culture and Communication.
    Bertilsson, Ann-Christine
    Mälardalen University, School of Education, Culture and Communication.
    Nyutbildade lärares reflektioner och upplevelser av sina första år i yrkeslivet2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Vårt syfte med studien är att undersöka och jämföra nyutbildade lärares reflektioneroch upplevelser under deras första tid i yrket. Studien är kvalitativ och inspirerad av fenomenografisk forskning där vi har intervjuat åtta lärare iförskolan och skolan.Resultatet visar att flertalet av lärarna upplevde att de fick en bra yrkesstart och ett bra bemötande av personalen på arbetsplatsen, och att de hade ett bra samarbete med mentorn. Det framkom också hur lärarna socialiserades in i yrket beträffande allt från lärarkontakt till föräldrakontakt och att lärarna hade olika förväntningar gällande läraryrket och lärarrollen. Det som framkom tydligast i vår studie var VFU­praktikens starka betydelse och besvikelsen över utbildningens brister.

  • 1158111.
    Yedugundla, Kiran
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Evaluating and Reducing Multipath Transport Latency2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Access to the Internet is a very significant part of everyday life with increasing online services such as news delivery, banking, gaming, audio and high quality movies. Applications require different transport guarantees with some requiring higher bandwidth and others low latency. Upgrading access link capacity does not guarantee faster access to the Internet as it offers higher bandwidth but may not offer low latency. With increasing number of mobile devices supporting more than one access technologies (e.g., WLAN, 3G, 4G,..), there is a need to analyse the impact of using multiple such technologies at the same time. Legacy transport protocols such as TCP or SCTP are only able to connect to one access network at a time to create an end-to-end connection. When more than one access technology is used, there may be a large difference in the data rate offered by each technology. This asymmetry might impact latency sensitive applications by creating out of order delivery. In this thesis, we focus on the latency aspect of multipath transport protocol performance. We consider CMT-SCTP and Multipath TCP as available multipath protocols that were designed for exploiting multiple paths for better throughput and reliability. We consider various real world traffic scenarios such as Video, Gaming and Web traffic to measure end-to-end latency. We perform simulations, emulations and experiments using heterogeneous network settings involving access networks with different bandwidth, delay and loss characteristics. MPTCP performs better in terms of latency than CMT-SCTP and TCP in certain scenarios where available paths are symmetric. However, MPTCP does not perform well in asymmetric scenarios with latency sensitive traffic. This analysis provides insights in to various areas of improvement in MPTCP such as scheduling and loss recovery to achieve low latency. We further focus on packet loss recovery in MPTCP for specific cases of tail losses to reduce latency. Tail losses are the losses that occur at the end of a packet stream. Recovering such losses is of higher significance to latency sensitive applications. We propose a modification to the use of TLP, a mechanism in TCP for tail loss recovery. We evaluate the performance of proposed TLP modification, first using emulations and with real world network experiments. Our results show significant improvements in latency for specific loss scenarios in emulations and up to 50% improvement in experiments.

  • 1158112.
    Yedugundla, Kiran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Handling Packet Losses in Cloud-Based Application Traffic2019In: Proceedings of the 9th International Conference on Cloud Computing and Services Science - Volume 1: CLOSER, SciTePress, 2019, p. 111-119Conference paper (Refereed)
    Abstract [en]

    Internet traffic is comprised of data flows from various applications with unique traffic characteristics. For many cloud applications, end-to-end latency is a primary factor affecting the perceived user experience. As packet losses cause delays in the communication they impact user experience, making efficient handling of packet losses an important function of transport layer protocols. Multipath TCP (MPTCP) is a modification to TCP that enables simultaneous use of several paths for a TCP flow. MPTCP is known to improve throughput. However, the performance of MPTCP is not optimal when handling certain loss scenarios. Efficient packet loss recovery is thus important to achieve desirable flow completion times for interactive cloud-based applications. In this paper we evaluate the performance of MPTCP in handling tail losses using traffic traces from various cloud-based applications. Tail losses, losses that occur at the end of a flow or traffic burst, are particularly challenging from a latency perspective as they are difficult to detect and recover in a timely manner. Tail losses in TCP are handled by using a tail loss probe (TLP) mechanism which was adapted to MPTCP from TCP. We investigate the performance of TLP in MPTCP, comparing the standard implementation to a recently proposed, less conservative approach. Our experimental results show that a less conservative implementation of TLP performs significantly better than the standard implementation in handling tail losses, reducing the average burst completion time of cloud based applications when tail loss occurs by up to 50% in certain cases.

  • 1158113.
    Yedugundla, Kiran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Multipath TCP: Can it Reduce Transport Latency for Web Traffic?2015Conference paper (Refereed)
  • 1158114.
    Yedugundla, Kiran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Probe or Wait: Handling tail losses using Multipath TCP2017In: 2017 IFIP Networking Conference (IFIP Networking) and Workshops, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    Packet losses are known to affect the performance of latency sensitive Internet applications such as media streaming and gaming. Transport protocols recover from packet loss in order to provide reliable end-to-end communication and improve user experience. The efficiency of loss recovery mechanisms influences the completion time of flows, and thus also the application performance as perceived by the end user. In this paper we focus on state-of-the-art loss recovery mechanisms for TCP and Multipath TCP. We use controlled tail loss scenarios to evaluate the performance of loss recovery mechanisms and, based on the observations, we propose an enhanced tail loss recovery mechanism for Multipath TCP, to improve the loss recovery time. Our experiment results, using the Linux Multipath TCP implementation, show consistent end-to-end latency performance improvement in considered scenarios.

  • 1158115.
    Yedugundla, Venkata Kiran
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Ferlin, Simone
    Simula Research Laboratory, Oslo, Norway.
    Dreibholz, Thomas
    Simula Research Laboratory, Oslo, Norway.
    Alay, Özgü
    Simula Research Laboratory, Oslo, Norway.
    Kuhn, Nicolas
    IMT Télécom Bretagne, IRISA, Cesson-Sévigné, France.
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunstrom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Is Multi-Path Transport Suitable for Latency Sensitive Traffic?2016In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 105, p. 1-21Article in journal (Refereed)
    Abstract [en]

    This paper assesses whether multi-path communication can help latency-sensitive applications to satisfy the requirements of their users. We consider Concurrent Multi-path Transfer for SCTP (CMT-SCTP) and Multi-path TCP (MPTCP) and evaluate their proficiency in transporting video, gaming, and web traffic over combinations of WLAN and 3G interfaces. To ensure the validity of our evaluation, several experimental approaches were used including simulation, emulation and live experiments. When paths are symmetric in terms of capacity, delay and loss rate, we find that the experienced latency is significantly reduced, compared to using a single path. Using multiple asymmetric paths does not affect latency - applications do not experience any increase or decrease, but might benefit from other advantages of multi-path communication. In the light of our conclusions, multi-path transport is suitable for latency-sensitive traffic and mature enough to be widely deployed. 

  • 1158116.
    Yedur, Sanjay K
    et al.
    Michigan State University.
    Berglund, Kris
    Use of fluorescence spectroscopy in concentration and supersaturation measurements in citric acid solutions1996In: Applied Spectroscopy, ISSN 0003-7028, E-ISSN 1943-3530, Vol. 50, no 7, p. 866-870Article in journal (Refereed)
    Abstract [en]

    Measurement of supersaturation is of critical importance in the operation and control of crystallizers. In this work, we report a novel spectroscopic technique to achieve the measurement of concentration and supersaturation in crystallizing solutions. In order to develop a sensor for this measurement, citric acid is chosen as the model solute, and the analytical technique involves fluorescence spectroscopy. Citric acid is a common food-grade compound with a wide range of applications that is exclusively produced by crystallization. The fluorescent properties of a probe, 8-hydroxy-1,3,6-pyrenetrisulfonate (pyranine), are used to provide concentration measurements in aqueous citric acid solutions, thereby providing for supersaturation estimation. The change in the relative emission peak intensities of the probe in different solute concentrations gives an excellent calibration curve for concentration measurements. It is also shown that, although pyranine responds to both its solvent microenvironment and the pH of the solution, it is still possible to measure concentration and supersaturation by using this fluorescence technique.

  • 1158117.
    Yedur, Sanjay K.
    et al.
    Michigan State University.
    Dulebohn, Joel
    Grand River Technologies, Lansing, MI.
    Werpy, Todd
    Michigan Biotechnology Institute, Lansing.
    Berglund, Kris
    Synthesis and testing of catalysts for the production of maleic anhydride from a fermentation feedstock1996In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 35, no 3, p. 663-671Article in journal (Refereed)
    Abstract [en]

    It is necessary to develop alternate pathways for the production of chemicals that are traditionally produced from fossil fuels to reduce our dependency on nonrenewable energy sources. In this paper, an alternate technology is presented for producing maleic anhydride from a fermentation feedstock. The process involves the catalytic oxydehydrogenation of fermentation-derived succinic anhydride to produce maleic anhydride. Various catalysts have been synthesized and tested for the oxydehydrogenation reaction. Iron phosphate based catalysts are found to be the best on the basis of high conversions and selectivities obtained. The effects of temperature, oxygen concentration, contact time, and the total time on stream on the performance of the catalyst are investigated, and an optimum set of conditions for the operation of the bench-scale reactor is presented. The bulk and surface compositions, the surface areas, and the bulk crystallographic structure of the catalysts are also reported.

  • 1158118.
    Yedurupak, Aruna Kumari
    KTH, School of Information and Communication Technology (ICT).
    Multitenant PrestoDB as a service2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, there has been tremendous growth in both the volumes of data that is produced, stored, and queried by organizations. Organizations spend more money to investigate and obtain useful information or knowledge against terabytes and even petabytes of data. Large-scale data analysis is the key functionality provided by Big Data platforms. Previously, data platforms would get the information from unstructured data in the form of files, text, and videos. In recent times, the Hadoop stack has played a vital role in Big Data, becoming the defector open source software used to process and analyze Big Data.

    Hops is a Hadoop distribution developed by KTH and RISE SICS. Hops modifies the Hadoop stack by moving the meta-data for YARN and HDFS to NDB, an open-source in-memory distributed database. HopsWorks is the User Interface for Hops and provides support for multi-tenant users, as well as self-service, graphical access to frameworks such as Hadoop, Flink, Spark, Kafka, and Kibana. HopsWorks currently does not provide a SQL-on-Hadoop service, although work is ongoing for supporting Hive. Presto is one of the main SQL-on-Hadoop platform, but, currently, Presto does not provide multi-tenancy support for users. This thesis investigates providing multitenancy support to Presto with the help of HopsWorks, including both the security problem and the self-service UI requirements of HopsWorks.

    Presto is a distributed SQL query Engine which can run SQL queries against up to petabytes of data. As HopsWorks provides UI access to services, we decided to build our UI for Presto on an existing open-source UI for Presto, called Airpal, developed by Airbnb. This provided solution of the thesis divided into two functionalities. First one, maintain two separate Applications (HopsWorks and Airpal Applications) run by the help of two JVMs and maintain ProxyServlet to control traffic between them. Second one HopsWorks-Presto-service leverages HopsWorks access-control (Data owner and Data-scientist) and self-service security model. The evaluation of the thesis used qualitative approach by comparing HopsWorks-PrestoService with standalone PrestoDB and comparing HopsWorks-PrestoService with HopsWorks without Presto-Service.

  • 1158119. Yee, B K
    et al.
    Zhu, S-W
    Mohammed, A H
    Växjö University, Faculty of Humanities and Social Sciences, School of Social Sciences.
    Feldon, J
    Levels of neurotrophic factors in the hippocampus and amygdala correlate with anxiety- and fear-related behaviour in C57BL6 mice.2007In: J Neural Transm, ISSN 0300-9564, Vol. 114, no 4, p. 431-44Article in journal (Other academic)
  • 1158120. Yee, B.
    et al.
    Mahajan, M.
    Seeger, C.
    Hägglund, E.
    Lind, S.
    Andersson, S.G.E.
    Natural competence in the Planctomycetes and its use in transforming the Gemmata-related species Tuwongella immobilis2019Manuscript (preprint) (Other (popular science, discussion, etc.))
  • 1158121.
    Yee Fan, Hiu
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Economics.
    The parental leave insurance in Sweden: A study of the causal effects on average parental leave use by the gender equality bonus reforms in 2008 and 20122015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper analyses if the gender equality bonus have any causal effects on average parental leave use. There are two reforms concerning the gender equality bonus. The first is the introduction of the bonus in 2008 and the second is the simplification of the bonus in 2012. Medium-term effects is studied on the first reform and short-term effects on the second. Further, this paper also investigates if there are any indirect differences between high income earners and non-high income earners in their average distribution of parental leave. In this thesis a difference-in-differences approach is used with control and treatment groups right before and after the policy changes. The results indicate that the 2008-reform does not have statistical significant causal effects on average parental leave, even on medium-term. The results are persistent when the studied population is divided into high- and non-high income earners. The reform in 2012 consists of the simplification of the bonus and in addition also the double days, therefore only a net effect of the reform could be estimated. The analysis made for the second reform does indicate significant causal effects on average parental leave use. The result shows that mothers and fathers have statistically increased and decreased their average parental leave on 5 and 10 percent significant level, respectively. This result contradicts to the expectations. If the gender equality bonus would have a causal effect on encouraging parents to share the leave more equally, the opposite results is expected. Analyzing the parents separately, conditioned on their income levels, the non-high income group suggests no statistical significant causal effects on average leave for neither mothers nor fathers. For the high income group, there is a significant increase of mothers’ average use of parental leave by around four percentage points. The significant increase for mothers average parental leave use due to the reform in 2012 is more likely to be explained by the double days rather than the gender equality bonus.

  • 1158122.
    Yee, H. C.
    et al.
    NASA, Ames Res Ctr, Moffett Field, CA 94035 USA..
    Sjogreen, B.
    KTH.
    Adaptive numerical dissipation control in high order schemes for multi-D non-ideal MHD2006In: COMPUTATIONAL FLUID DYNAMICS 2004, PROCEEDINGS / [ed] Groth, C Zingg, DW, SPRINGER-VERLAG BERLIN , 2006, p. 407-+Conference paper (Refereed)
  • 1158123. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Adaptive filtering and limiting in compact high order methods for multiscale gas dynamics and MHD systems2008In: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 37, no 5, p. 593-619Article in journal (Refereed)
    Abstract [en]

    The adaptive multistep linear and nonlinear filters for multiscale shock/turbulence gas dynamics and magnetohydrodynamics (MHD) flows of the authors are extended to include compact high order central differencing as the spatial base scheme. The adaptive mechanism makes used of multiresolution wavelet decomposition of the computed flow data as sensors for numerical dissipative control. The objective is to expand the work initiated in [Yee HC, Sjogreen B. Nonlinear filtering in compact high order schemes. In: Proceedings of the 19th ICNSP and 7th APPTC conference; 2005; J Plasma Phys 2006;72:833-36] and compare the performance of adaptive multistep filtering in compact high order schemes with adaptive filtering in standard central (non-compact) schemes for multiscale problems containing shock waves.

  • 1158124. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
    Designing adaptive low-dissipative high order schemes for long-time integrations2004In: Turbulent flow computation, Kluwer Academic Publishers, 2004, p. 141-198Chapter in book (Refereed)
    Abstract [en]

    A general framework for the design of adaptive low-dissipative high order schmes is presented. It encompasses a rather complete treatment of the numerical approach based on four integrated design criteria: (1) For stability considerations, condition the governing equations before the application of the appropriate numerical scheme whenever it is possible. (2) For consistency, compatible schemes that possess stability properties, including physical and numerical boundary condition treatments, similar to those of the discrete analogue of the continuum are preferred. (3) For the minimization of numerical dissipation contamination, efficient and adaptive numerical dissipation control to further improve nonlinear stability and accuracy should be used. (4) For practical considerations, the numerical approach should be efficient and applicable to general geometries, and an efficient and reliable dynamic grid adaptation should be used if necessary. These design criteria are, in general, very useful to a wide spectrum of flow simulations. However, the demand on the overall numerical approach for nonlinear stability and accuracy is much more stringent for long-time integration of complex multiscale viscous shock/shear/turbulence/acoustics interactions and numerical combustion. Robust classical numerical methods for less complex flow physics are not suitable or practical for such applications. The present approach is designed expressly to address such flow problems, especially unsteady flows. The minimization of employing very fine grids to overcome the production of spurious numerical solutions and/or instability due to under-resolved grids is also sought [79, 17]. The incremental studies to illustrate the performance of the approach are summarized. Extensive testing and full implementation of the approach is forthcoming. The results shown so far are very encouraging.

  • 1158125. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Development of low dissipative high order filter schemes for multiscale Navier-Stokes/MHD systems2006In: Numerical Modeling of Space Plasma Flows: Astronum-2006 / [ed] Pogorelov, N; Zank, GP, SAN FRANCISCO: ASTRONOMICAL SOC PACIFIC , 2006, Vol. 359, p. 47-61Conference paper (Refereed)
    Abstract [en]

    Recent progress in the development of a class of low dissipative high order filter schemes for multiscale Navier-Stokes, and ideal and non-ideal magnetohydrodynamics (MHD) systems is described. The four main features of this schemes are: (a) multiresolution wavelet decomposition of the computed flow data as sensors for adaptive numerical dissipative control, (b) multistep filter to accommodate efficient application of different numerical dissipation models and different spatial high order base schemes, (c) solving the ideal conservative MHD system without having to deal with an incomplete eigensystern set while at the same time ensuring that correct shock speeds and locations are computed, and (d) minimization of the divergence of the magnetic field (del(.) B) numerical error. By design, the flow sensors, different choice of high order base schemes and numerical dissipation models are stand-alone modules. A whole class of low dissipative high order schemes can be derived at ease, making the resulting computer software very flexible with widely applicable.

  • 1158126. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Development of low dissipative high order filter schemes for multiscale Navier-Stokes/MHD systems2007In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 225, no 1, p. 910-934Article in journal (Refereed)
    Abstract [en]

    Recent progress in the development of a class of low dissipative high order (fourth-order or higher) filter schemes for multiscale Navier-Stokes, and ideal and non-ideal magnetohydrodynamics (MHD) systems is described. The four main features of this class of schemes are: (a) multiresolution wavelet decomposition of the computed flow data as sensors for adaptive numerical dissipative control, (b) multistep filter to accommodate efficient application of different numerical dissipation models and different spatial high order base schemes, (c) a unique idea in solving the ideal conservative MHD system (a non-strictly hyperbolic conservation law) without having to deal with an incomplete eigensystem set while at the same time ensuring that correct shock speeds and locations are computed, and (d) minimization of the divergence of the magnetic field (del center dot B) numerical error. By design, the flow sensors, different choice of high order base schemes and numerical dissipation models are stand-alone modules. A whole class of low dissipative high order schemes can be derived at ease, making the resulting computer software very flexible with widely applicable. Performance of multiscale and multiphysics test cases are illustrated with many levels of grid refinement and comparison with commonly used schemes in the literature.

  • 1158127. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Efficient low dissipative high order schemes for multiscale MHD flows, II: Minimization of del center dot B numerical error2006In: Journal of Scientific Computing, ISSN 0885-7474, E-ISSN 1573-7691, Vol. 29, no 1, p. 115-164Article in journal (Refereed)
    Abstract [en]

    An adaptive numerical dissipation control in a class of high order filter methods for compressible MHD equations is systematically discussed. The filter schemes consist of a divergence-free preserving high order spatial base scheme with a filter approach which can be divergence-free preserving depending on the type of filter operator being used, the method of applying the filter step, and the type of flow problem to be considered. Some of these filter variants provide a natural and efficient way for the minimization of the divergence of the magnetic field (del center dot B) numerical error in the sense that commonly used divergence cleaning is not required. Numerical experiments presented emphasize the performance of the del center dot B numerical error. Many levels of grid refinement and detailed comparison of the filter methods with several commonly used compressible MHD shock-capturing schemes will be illustrated.

  • 1158128. Yee, H C
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Non-linear filtering and limiting in high order methods for ideal and non-ideal MHD2006In: Journal of Scientific Computing, ISSN 0885-7474, E-ISSN 1573-7691, Vol. 27, no 1-3, p. 507-521Article in journal (Refereed)
    Abstract [en]

    The adaptive nonlinear filtering and limiting in spatially high order schemes (Yee et al. J. Comput. Phys. 150, 199 - 238, ( 1999), Sjogreen and Yee, J. Scient. Comput. 20, 211 - 255, ( 2004)) for the compressible Euler and Navier - Stokes equations have been recently extended to the ideal and non-ideal magnetohydrodynamics (MHD) equations, (Sjogreen and Yee, ( 2003), Proceedings of the 16th AIAA/CFD conference, June 23 - 26, Orlando F1; Yee and Sjogreen ( 2003), Proceedings of the International Conference on High Performance Scientific Computing, March, 10 - 14, Honai, Vietnam; Yee and Sjogreen ( 2003), RIACS Technical Report TR03. 10, July, NASA Ames Research Center; Yee and Sjogreen ( 2004), Proceedings of the ICCF03, July 12 - 16, Toronto, Canada). The numerical dissipation control in these adaptive filter schemes consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. The numerical dissipation considered consists of high order linear dissipation for the suppression of high frequency oscillation and the nonlinear dissipative portion of high-resolution shock-capturing methods for discontinuity capturing. The applicable nonlinear dissipative portion of high-resolution shock-capturing methods is very general. The objective of this paper is to investigate the performance of three commonly used types of discontinuity capturing nonlinear numerical dissipation for both the ideal and non-ideal MHD.

  • 1158129. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis, NA.
    Nonlinear filtering in compact high-order schemes2006In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 72, p. 833-836Article in journal (Refereed)
    Abstract [en]

    The adaptive nonlinear filtering approach for shock/turbulence gas dynamics and magnetohydrodynamics (MHD) flows adopted in our previous world is employed in conjunction with compact high-order methods as the spatial base scheme. The objective is to compare the performance of nonlinear filtering in compact high-order schemes with nonlinear filtering in standard central (non-compact) schemes for multiseale problems containing shock waves.

  • 1158130. Yee, H. C.
    et al.
    Sjögreen, Björn
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Simulation of Richtmyer-Meshkov instability by sixth-order filter methods2007In: Shock Waves, ISSN 0938-1287, E-ISSN 1432-2153, Vol. 17, no 3, p. 185-193Article in journal (Refereed)
    Abstract [en]

    Simulation of a 2-D Richtmyer-Meshkov instability (RMI), including inviscid, viscous and magnetic field effects was conducted comparing recently developed sixth-order filter schemes with various standard shock-capturing methods. The suppression of the inviscid gas dynamics RMI in the presence of a magnetic field was investigated by Samtaney and Wheatley et al. Numerical results illustrated here exhibit behavior similar to the work of Samtaney. Due to the different amounts and different types of numerical dissipation contained in each scheme, the structures and the growth of eddies for the chaotic-like inviscid gas dynamics RMI case are highly grid size and scheme dependent, even with many levels of refinement. The failure of grid refinement for all studied numerical methods extends to the viscous gas dynamics case for high Reynolds number. For lower Reynolds number, grid convergence has been achieved by all studied methods. To achieve similar resolution, standard shock-capturing methods require more grid points than filter schemes and yet the CPU times using the same grid for all studied methods are comparable.

  • 1158131. Yee, Winston K. W.
    et al.
    Rogell, Björn
    Stockholm University, Faculty of Science, Department of Zoology. Monash University, Australia.
    Lemos, Bernardo
    Dowling, Damian K.
    Intergenomic interactions between mitochondrial and Y-linked genes shape male mating patterns and fertility in Drosophila melanogaster2015In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, no 11, p. 2876-2890Article in journal (Refereed)
    Abstract [en]

    Under maternal inheritance, mitochondrial genomes are prone to accumulate mutations that exhibit male-biased effects. Such mutations should, however, place selection on the nuclear genome for modifier adaptations that mitigate mitochondrial-incurred male harm. One gene region that might harbor such modifiers is the Y-chromosome, given the abundance of Y-linked variation for male fertility, and because Y-linked modifiers would not exert antagonistic effects in females because they would be found only in males. Recent studies in Drosophila revealed a set of nuclear genes whose expression is sensitive to allelic variation among mtDNA-and Y-haplotypes, suggesting these genes might be entwined in evolutionary conflict between mtDNA and Y. Here, we test whether genetic variation across mtDNA and Y haplotypes, sourced from three disjunct populations, interacts to affect male mating patterns and fertility across 10 days of early life in D. melanogaster. We also investigate whether coevolved mito-Y combinations outperform their evolutionarily novel counterparts, as predicted if the interacting Y-linked variance is comprised of modifier adaptations. Although we found no evidence that coevolved mito-Y combinations outperformed their novel counterparts, interactions between mtDNA and Y-chromosomes affected male mating patterns. These interactions were dependent on male age; thus male reproductive success was shaped by G x G x E interactions.

  • 1158132.
    Yefanova, Iryna
    Linnaeus University, Faculty of Social Sciences, Department of Social Studies.
    Examining framing effects on the decision-making processes of households in energy investments: An online experiment2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the increased energy demands which are needed to fuel the human development and economic growth we also observe a trend for global environmental problems caused by burning fossil fuels. Tackling problems like global warming would mean either tapping into the large CO2 emitters and having them shift to renewable energy alternatives or motivating change on the level of individuals which would lead to a general reduction in energy consumption.

    This thesis features an online experiment with 320 participants, recruited through Amazon Mechanical Turk, who were randomly assigned to either an environmental or an economic frame, and performed tasks on energy-related investments, risk elicitation and environmental preferences (by framing we mean controlling the formulation of the decision problem). The main purpose of the experiment was to examine the effects of framing on the decision-making processes of households in regards to energy investments.

    The results we obtained with 90 and 99% confidence provide evidence that framing does have an effect on investment choices, moreover we have also observed that environmental concern is an important predictor of households’ investments. Going beyond our main hypothesis, we have conducted some exploratory analysis of the data which highlighted a great potential for the scientific method within the domain of energy-related investments.

    Finally, the results from our experiment suggest that framing could be a successful instrument in the hands of those working with policy-making and communication.

  • 1158133. Yefenof, E
    et al.
    Ramos, O F
    Nilsson, B
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Klein, E
    Ligands of CR2 do not interfere with C3 fragment fixation or enhanced NK sensitivity of Raji cells treated with human serum.1989In: Immunology Letters, ISSN 0165-2478, E-ISSN 1879-0542, Vol. 21, no 4, p. 303-306Article in journal (Refereed)
    Abstract [en]

    Raji cells activate the alternative complement pathway (ACP) and fix C3 fragments when incubated in human serum (HS). Earlier experiments have shown that CR2 molecules are involved in this phenomenon and the opsonized cells have elevated sensitivity to the lytic effect of CR3-bearing NK cells. We show here that Raji cells treated with CR2 site-specific ligands, (C3d, OKB-7 and HB-5 mAbs, and a synthetic peptide which binds to CR2) generated and bound C3 fragments after exposure to HS. The elevated lytic sensitivity of HS-treated cells was not altered by the presence of the various CR2 ligands. Thus, the membrane-bound C3 fragments are not fixed at the C3dg receptor binding site.

  • 1158134.
    Yeganeh, Behzad
    et al.
    Department of Physiology, University of Manitoba, Winnipeg, Canada.
    Hashemi, Mohammad
    Cellular and Molecular Research Center, Zahedan University of Medical Sciences, Iran.
    de Serres, Fredrick J.
    Center for Evaluation of Risks to Human Reproduction, National Institute of Environmental Health Sciences, Research Triangle Park, Iran.
    Los, Marek Jan
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Ghavami, Saeid
    University of Manitoba, Winnipeg, Canada.
    Different Faces of Hepatocellular Carcinoma as a Health Threat in 21st Century2013In: Hepatitis Monthly, ISSN 1735-143X, E-ISSN 1735-3408, Vol. 13, no 2Article in journal (Other academic)
  • 1158135.
    Yeganeh, Behzad
    et al.
    University of Toronto, Toronto, Canada.
    Moghadam, Adel R
    Islamic Azad University, Ardabil, Iran.
    Alizadeh, Javad
    University of Manitoba, Winnipeg Canada.
    Wiechec, Emilia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Alavian, Seyed M
    Baqiyatallah Research Center for Gastroenterology and Liver Disease, Tehran, Iran.
    Hashemi, Mohammad
    Zahedan University of Medical Sciences, Zahedan, Iran.
    Geramizadeh, Bita
    Shiraz University of Medical Sciences, Shiraz, Iran.
    Samali, Afshin
    National University of Ireland Galway, Galway, Ireland.
    Lankarani, Kamran B
    Shiraz University of Medical Sciences, Shiraz, Iran.
    Post, Martin
    University of Toronto, Toronto, Canada.
    Peymani, Payam
    Shiraz University of Medical Sciences, Shiraz, Iran.
    Coombs, Kevin M
    University of Manitoba, Winnipeg, Canada.
    Ghavami, Saeid
    University of Manitoba, Winnipeg, Canada.
    Hepatitis B and C virus-induced hepatitis: apoptosis, autophagy and unfolded protein response.2015In: World Journal of Gastroenterology, ISSN 1007-9327, E-ISSN 2219-2840, Vol. 21, no 47, p. 13225-13239Article in journal (Refereed)
    Abstract [en]

    AIM: To investigate the co-incidence of apoptosis, autophagy, and unfolded protein response (UPR) in hepatitis B (HBV) and C (HCV) infected hepatocytes.

    METHODS: We performed immunofluorescence confocal microscopy on 10 liver biopsies from HBV and HCV patients and tissue microarrays of HBV positive liver samples. We used specific antibodies for LC3β, cleaved caspase-3, BIP (GRP78), and XBP1 to detect autophagy, apoptosis and UPR, respectively. Anti-HCV NS3 and anti-HBs antibodies were also used to confirm infection. We performed triple blind counting of events to determine the co-incidence of autophagy (LC3β punctuate), apoptosis (cleaved caspase-3), and unfolded protein response (GRP78) with HBV and HCV infection in hepatocytes. All statistical analyses were performed using SPSS software for Windows (Version 16 SPSS Inc, Chicago, IL, United States). P-values < 0.05 were considered statistically significant. Statistical analyses were performed with Mann-Whitney test to compare incidence rates for autophagy, apoptosis, and UPR in HBV- and HCV-infected cells and adjacent non-infected cells.

    RESULTS: Our results showed that infection of hepatocytes with either HBV and HCV induces significant increase (P < 0.001) in apoptosis (cleavage of caspase-3), autophagy (LC3β punctate), and UPR (increase in GRP78 expression) in the HCV- and HBV-infected cells, as compared to non-infected cells of the same biopsy sections. Our tissue microarray immunohistochemical expression analysis of LC3β in HBVNeg and HBVPos revealed that majority of HBV-infected hepatocytes display strong positive staining for LC3β. Interestingly, although XBP splicing in HBV-infected cells was significantly higher (P < 0.05), our analyses show a slight increase of XBP splicing was in HCV-infected cells (P > 0.05). Furthermore, our evaluation of patients with HBV and HCV infection based on stage and grade of the liver diseases revealed no correlation between these pathological findings and induction of apoptosis, autophagy, and UPR.

    CONCLUSION: The results of this study indicate that HCV and HBV infection activates apoptosis, autophagy and UPR, but slightly differently by each virus. Further studies are warranted to elucidate the interconnections between these pathways in relation to pathology of HCV and HBV in the liver tissue.

  • 1158136.
    Yeganeh, Behzad
    et al.
    University of Toronto, Canada.
    Wiechec, Emilia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Ande, Sudharsana R.
    University of Manitoba, Winnipeg, Canada.
    Sharma, Pawan
    University of Calgary, Alberta, Canada.
    Moghadam, Adel Rezaei
    Islamic Azad University, Tabriz, Iran.
    Post, Martin
    University of Toronto, Canada.
    Freed, Darren H.
    University of Manitoba, Winnipeg, Canada.
    Hashemi, Mohammad
    Zahedan University of Medical Sceinces, Iran.
    Shojaei, Shahla
    Shiraz University of Medical Sciences, Iran.
    Zeki, Amir A.
    U.C. Davis, School of Medicine, CA, USA.
    Ghavami, Saeid
    University of Manitoba, Winnipeg, Canada.
    Targeting the mevalonate cascade as a new therapeutic approach in heart disease, cancer and pulmonary disease2014In: Pharmacology and Therapeutics, ISSN 0163-7258, E-ISSN 1879-016X, Vol. 143, no 1, p. 87-110Article, review/survey (Refereed)
    Abstract [en]

    The cholesterol biosynthesis pathway, also known as the mevalonate (MVA) pathway, is an essential cellular pathway that is involved in diverse cell functions. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) is the rate-limiting step in cholesterol biosynthesis and catalyzes the conversion of HMG-CoA to MVA.

    Given its role in cholesterol and isoprenoid biosynthesis, the regulation of HMGCR has been intensely investigated. Because all cells require a steady supply of MVA, both the sterol (i.e. cholesterol) and non-sterol (i.e. isoprenoid) products of MVA metabolism exert coordinated feedback regulation on HMGCR through different mechanisms. The proper functioning of HMGCR as the proximal enzyme in the MVA pathway is essential under both normal physiologic conditions and in many diseases given its role in cell cycle pathways and cell proliferation, cholesterol biosynthesis and metabolism, cell cytoskeletal dynamics and stability, cell membrane structure and fluidity, mitochondrial function, proliferation, and cell fate.

    The blockbuster statin drugs (‘statins’) directly bind to and inhibit HMGCR, and their use for the past thirty years has revolutionized the treatment of hypercholesterolemia and cardiovascular diseases, in particular coronary heart disease. Initially thought to exert their effects through cholesterol reduction, recent evidence indicates that statins also have pleiotropic immunomodulatory properties independent of cholesterol lowering.

    In this review we will focus on the therapeutic applications and mechanisms involved in the MVA cascade including Rho GTPase and Rho kinase (ROCK) signaling, statin inhibition of HMGCR, geranylgeranyltransferase (GGTase) inhibition, and farnesyltransferase (FTase) inhibition in cardiovascular disease, pulmonary diseases (e.g. asthma and chronic obstructive pulmonary disease (COPD)), and cancer.

  • 1158137.
    Yeganeh, Elaheh
    Stockholm University, The Stockholm Institute of Education.
    Lönar sig laborativt material för problemlösning?2007Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Under lärarutbildningen utvecklades mina idéer om varierande undervisningsmetoder för problemlösning. Då jag utförde min praktik fick jag uppleva hur arbete i en matematikverkstad kunde stimulera högstadieelevernas intresse för problemlösning samt stödja deras förmåga att lösa problem. Trots utveckling av varierande undervisning i matematik visar utvärderingar att ”enskild tyst räkning” fortfarande är dominerande på matematiklektionerna. Enligt rapporter från bland annat skolverket skapar sådan tyst räkning ointresse för ämnet och misslyckande för många elever. Avsikten med detta arbete var att undersöka hur användning av laborativa material vid matematisk problemlösning påverkar högstadieelevers förmåga att lösa problem och intresse för problemlösning. För undersökningen valdes en klass i årskurs 9 med 23 elever. Elevernas resultat jämfördes när de arbetade med likadana uppgifter i klassrummet och i matematikverkstaden. Enkätfrågor användes också för att veta hur skillnaden mellan sätten att arbeta upplevdes av eleverna. Denna studie visar att användning av laborativa material påverkar elevernas förmåga att lösa problem och intresse för problemlösning positivt.

  • 1158138.
    Yegezu, Mattias
    Jönköping University, Jönköping International Business School.
    Capital Structure Decisions Influence on Firm Performance: A Quantitative study on Large Manufacturers Operating in Sweden2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background & Problem: Financing is an integral part of any business and during recent years, financing decisions has been a widely debated topic. Theories takes different stances on how firms should finance their businesses based on the implication debt and equity have, while research shows inconsistent evidence. This have resulted in a field of uncertainty and gaps for researchers to exploit.

     

    Purpose: The purpose of the study is to investigate the relationship between capital structure and performance

     

    Method: A purely quantitative panel-data regression study investigating 314 of the largest public and private Sweden operating manufacturers during the years 2013-2017. With ROA as a performance measurement and dependent variable, Total Debt/Total Assets as measurement for capital structure. Size, Growth and Asset Structure as control variables.

     

    Conclusion: The results show that leverage have a significant negative relationship with ROA, during the years 2013-2017 and is consistent with the assumptions of the pecking-order theory.

  • 1158139.
    Yeghiazaryan, Sergey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Arroyo, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Kvalitetssäkring av servicelämnare för skogsbrukets arbetsmaskiner: Intervjuer och förslag till utveckling2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this study we have examined the possible quality standards and methods for applications with service workshops in the forest industry. The purpose of the methods presented here was to start the work of standarardising the maintenance service in the industry and be of use for service providers in their quality effort.

    The methods we used to accomplish the study were interviews and field visits together with a comprehensive literature research. Our results are presented in the form of four solution proposals: a standard based on existing SIS standards for terminology and key indicators, checklists that are filled in by mechanics with customer participation, the construction of a instructions database, and the implementation of the method 5s.

    We believe our suggestions can help the service providers in the four problem areas that we have identified: long term strategy, documentation, recruitment of competent technicians, and standard procedures in their operations. These improvements will be beneficial for both the service provider and the customer.

  • 1158140.
    Yeghsanian, Rima-Rita
    University College of Arts, Crafts and Design, Institutionen för Bildpedagogik (BI).
    Negern finns inte. Inte mer än den vite: ett arbete om invandrare, identitet och språk1996Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 1158141. Yego, Faith
    et al.
    D'Este, Catherine
    Byles, Julie
    Stewart Williams, Jennifer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Nyongesa, Paul
    Risk factors for maternal mortality in a Tertiary Hospital in Kenya: a case control study2014In: BMC Pregnancy and Childbirth, ISSN 1471-2393, E-ISSN 1471-2393, Vol. 14, article id 38Article in journal (Refereed)
    Abstract [en]

    Background: Maternal mortality is high in Africa, especially in Kenya where there is evidence of insufficient progress towards Millennium Development Goal (MDG) Five, which is to reduce the global maternal mortality rate by three quarters and provide universal access to reproductive health by 2015. This study aims to identify risk factors associated with maternal mortality in a tertiary level hospital in Kenya. Methods: A manual review of records for 150 maternal deaths (cases) and 300 controls was undertaken using a standard audit form. The sample included pregnant women aged 15-49 years admitted to the Obstetric and Gynaecological wards at the Moi Teaching and Referral Hospital (MTRH) in Kenya from January 2004 and March 2011. Logistic regression analysis was used to assess risk factors for maternal mortality. Results: Factors significantly associated with maternal mortality included: having no education relative to secondary education (OR 3.3, 95% CI 1.1-10.4, p = 0.0284), history of underlying medical conditions (OR 3.9, 95% CI 1.7-9.2, p = 0.0016), doctor attendance at birth (OR 4.6, 95% CI 2.1-10.1, p = 0.0001), having no antenatal visits (OR 4.1, 95% CI 1.6-10.4, p = 0.0007), being admitted with eclampsia (OR 10.9, 95% CI 3.7-31.9, p < 0.0001), being admitted with comorbidities (OR 9.0, 95% CI 4.2-19.3, p < 0.0001), having an elevated pulse on admission (OR 10.7, 95% CI 2.7-43.4, p = 0.0002), and being referred to MTRH (OR 2.1, 95% CI 1.0-4.3, p = 0.0459). Conclusions: Antenatal care and maternal education are important risk factors for maternal mortality, even after adjusting for comorbidities and complications. Antenatal visits can provide opportunities for detecting risk factors for eclampsia, and other underlying illnesses but the visits need to be frequent and timely. Education enables access to information and helps empower women and their spouses to make appropriate decisions during pregnancy.

  • 1158142. Yego, Faith H
    et al.
    D Este, Catherine
    Byles, Julie
    Nyongesa, Paul
    Williams, Jennifer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Research Centre for Gender, Health and Ageing, University of Newcastle, Newcastle, Australia.
    A case-control study of risk factors for fetal and early neonatal deaths in a tertiary hospital in Kenya2014In: BMC Pregnancy and Childbirth, ISSN 1471-2393, E-ISSN 1471-2393, Vol. 14, p. 389-Article in journal (Refereed)
    Abstract [en]

    BackgroundIt is important to understand the risk factors for fetal and neonatal mortality which is a major contributor to high under five deaths globally. Fetal and neonatal mortality is a sensitive indicator of maternal health in society. This study aimed to examine the risk factors for fetal and early neonatal mortality at the Moi Teaching and Referral Hospital in Kenya.MethodsThis was a case-control study. Cases were fetal and early neonatal deaths (n¿=¿200). The controls were infants born alive immediately preceding and following the cases (n¿=¿400). Bivariate comparisons and multiple logistic regression analyses were undertaken.ResultsThe odds of having 0-1 antenatal visits relative to 2-3 visits were higher for cases than controls (AOR=4.5; 95% CI: 1.2-16.7; p=0.03). There were lower odds among cases of having a doctor rather than a midwife as a birth attendant (OR¿=¿0.2; 95% CI: 0.1-0.6; p¿<¿0.01). The odds of mothers having Premature Rupture of Membranes (OR¿=¿4.1; 95% CI: 1.4-12.1; p¿=¿0.01), haemorrhage (OR¿=¿4.8; 95% CI: 1.1-21.9; p¿=¿0.04) and dystocia (OR¿=¿3.6; 95% CI: 1.2-10.9; p¿=¿0.02) were higher for the cases compared with the controls. The odds of gestational age less than 37 weeks (OR¿=¿7.0; 95% CI 2.4-20.4) and above 42 weeks (OR¿=¿16.2; 95% CI 2.8-92.3) compared to 37-42 weeks, were higher for cases relative to controls (p¿<¿0.01). Cases had higher odds of being born with congenital malformations (OR¿=¿6.3; 95% CI: 1.2-31.6; p¿=¿0.04) and with Apgar scores of below six at five minutes (OR¿=¿26.4; 95% CI: 6.1-113.8; p¿<¿0.001).ConclusionInterventions that focus on educating mothers on antenatal attendance, screening, monitoring and management of maternal conditions during the antenatal period should be strengthened. Doctor attendance at each birth and for emergency admissions is important to ensure early neonatal survival and avert potential risk factors for mortality.

  • 1158143. Yego, Faith
    et al.
    Stewart Williams, Jennifer
    Research Centre for Gender, Health and Ageing, HMRI Building, University of Newcastle, University Drive, 2308, Callaghan, NSW, Australia.
    Byles, Julie
    Nyongesa, Paul
    Aruasa, Wilson
    D'Este, Catherine
    A retrospective analysis of maternal and neonatal mortality at a teaching and referral hospital in Kenya2013In: Reproductive health, ISSN 1742-4755, Vol. 10, p. 13-Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To measure the incidence of maternal and early neonatal mortality in women who gave birth at Moi Teaching and Referral Hospital (MTRH) in Kenya and describe clinical and other characteristics and circumstances associated with maternal and neonatal deaths following deliveries at MTRH.

    METHODS: A retrospective audit of maternal and neonatal records was conducted with detailed analysis of the most recent 150 maternal deaths and 200 neonatal deaths. Maternal mortality ratios and early neonatal mortality rates were calculated for each year from January 2004 to December 2011.

    RESULTS: Between 2004 and 2011, the overall maternal mortality ratio was 426 per 100,000 live births and the early neonatal mortality rate (<7 days) was 68 per 1000 live births. The Hospital record audit showed that half (51%) of the neonatal mortalities were for young mothers (15-24 years) and 64% of maternal deaths were in women between 25 and 45 years. Most maternal and early neonatal deaths occurred in multiparous women, in referred admissions, when the gestational age was under 37 weeks and in latent stage of labour. Indirect complications accounted for the majority of deaths. Where there were direct obstetric complications associated with the delivery, the leading cause of maternal death was eclampsia and the leading cause of early neonatal death was pre-mature rupture of membranes. Pre-term birth and asphyxia were leading causes of early neonatal deaths. In both sets of records the majority of deliveries were vaginal and performed by midwives.

    CONCLUSION: This study provides important information about maternal and early neonatal mortality in Kenya's second largest tertiary hospital. A range of socio demographic, clinical and health system factors are identified as possible contributors to Kenya's poor progress towards reducing maternal and early neonatal mortality.

  • 1158144.
    Yegorova, Olga
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Informatics and Media.
    #NiUnaMenosBolivia fights back: A discourse theoretical analysis on the struggle against gender-based violence in Bolivia2017Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Femicides are not a new phenomenon. Marches involving thousands of people all around the Latin American continent to fight them, however, is. Ni Una Menos - Not one woman less - is the slogan that also mobilized Bolivians to mass-based protests in November 2016.This thesis investigates the counterpublic of #NiUnaMenosBolivia for the purpose of understanding its discursively articulated identities. A multidisciplinary discourse theoretical analysis combines Ernesto Laclau and Chantal Mouffe’s discourse theory with Nancy Fraser’s contributions to the struggle over needs of counterpublics to examine textual, photographic and ethnographic data.Two levels of identities of #NiUnaMenos are extracted from the investigation: Internal agonistic identities pinpoint at the friction between the representors and the represented identities of the counterpublic. A collective identity evolves in the context of the struggle for justice, freedom and dignity through the construction of an antagonistic “Others” who are held responsible for femicidal violence.This study builds a bridge between feminist activism and academic discourse for feminist studies of the region. It further develops and exemplifies a methodological toolkit for a theoretically based discourse analysis on contemporary women’s movements.

  • 1158145.
    Yeh, Alexander
    et al.
    Chalmers University of Technology, Gothenburg, Sweden.
    Ratsamee, Photchara
    Osaka University, Osaka, Japan.
    Kiyokawa, Kiyoshi
    Nara Institute of Science and Technology (NAIST), Nara, Japan.
    Uranishi, Yuki
    Osaka University, Osaka, Japan.
    Mashita, Tomohiro
    Osaka University, Osaka, Japan.
    Takemura, Haruo
    Osaka University, Osaka, Japan.
    Fjeld, Morten
    Chalmers University of Technology, Gothenburg, Sweden.
    Obaid, Mohammad
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Exploring proxemics for human-drone interaction2017In: Proc. 5th International Conference on Human Agent Interaction, New York: ACM Press, 2017, p. 81-88Conference paper (Refereed)
    Abstract [en]

    We present a human-centered designed social drone aiming to be used in a human crowd environment. Based on design studies and focus groups, we created a prototype of a social drone with a social shape, face and voice for human interaction. We used the prototype for a proxemic study, comparing the required distance from the drone humans could comfortably accept compared with what they would require for a nonsocial drone. The social shaped design with greeting voice added decreased the acceptable distance markedly, as did present or previous pet ownership, and maleness. We also explored the proximity sphere around humans with a social shaped drone based on a validation study with variation of lateral distance and heights. Both lateral distance and the higher height of 1.8 m compared to the lower height of 1.2 m decreased the required comfortable distance as it approached.

  • 1158146. Yeh, Johannes T. -H.
    et al.
    Nam, Kwangho
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, USA.
    Yeh, Joshua T. -H.
    Perrimon, Norbert
    eUnaG: a new ligand-inducible fluorescent reporter to detect drug transporter activity in live cells2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 41619Article in journal (Refereed)
    Abstract [en]

    The absorption, distribution, metabolism and excretion (ADME) of metabolites and toxic organic solutes are orchestrated by the ATP-binding cassette (ABC) transporters and the organic solute carrier family (SLC) proteins. A large number of ABC and SLC transpoters exist; however, only a small number have been well characterized. To facilitate the analysis of these transporters, which is important for drug safety and physiological studies, we developed a sensitive genetically encoded bilirubin (BR)-inducible fluorescence sensor (eUnaG) to detect transporter-coupled influx/efflux of organic compounds. This sensor can be used in live cells to measure transporter activity, as excretion of BR depends on ABC and SLC transporters. Applying eUnaG in functional RNAi screens, we characterize l(2) 03659 as a Drosophila multidrug resistant-associated ABC transporter.

  • 1158147. Yeh, S.
    et al.
    Berndes, G.
    Mishra, G.S
    Karlberg, Louise
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Evaluation of water use for bioenergy at different scales2011In: Biofuels, Bioproducts and Biorefining, ISSN 1932-104X, E-ISSN 1932-1031, Vol. 5, no 4, p. 361-374Article in journal (Refereed)
  • 1158148. Yeh, T.
    et al.
    Tollmar, Konrad
    MIT CSAIL, Cambridge.
    Darrell, T.
    Searching the Web with mobile images for location recognition2004In: PROCEEDINGS OF THE 2004 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, VOL 2, 2004, Vol. 2, p. 76-81Conference paper (Refereed)
    Abstract [en]

    We describe an approach to recognizing location from mobile devices using image-based Web search. We demonstrate the usefulness of common image search metrics applied on images captured with a camera-equipped mobile device to find matching images on the World Wide Web or other general-purpose databases. Searching the entire Web can be computationally overwhelming, so we devise a hybrid image-and-keyword searching technique. First, image-search is performed over images and links to their source Web pages in a database that indexes only a small fraction of the Web. Then, relevant keywords on these Web pages are automatically identified and submitted to an existing text-based search engine (e.g. Google) that indexes a much larger portion of the Web. Finally, the resulting image set is filtered to retain images close to the original query. It is thus possible to efficiently search hundreds of millions of images that are not only textually related but also visually relevant. We demonstrate our approach on an application allowing users to browse Web pages matching the image of a nearby location.

  • 1158149. Yeh, Tom
    et al.
    Grauman, Kristen
    Tollmar, Konrad
    Darrell, Trevor
    A picture is worth a thousand keywords: image-based object search on a mobile platform2005In: CHI ’05 extended abstracts on Human factors in computing systems, 2005, p. 2025-2028Conference paper (Refereed)
    Abstract [en]

    Finding information based on an object’s visual appearance is useful when specific keywords for the object are not known. We have developed a mobile image-based search system that takes images of objects as queries and finds relevant web pages by matching them to similar images on the web. Image-based search works well when matching full scenes, such as images of buildings or landmarks, and for matching objects when the boundary of the object in the image is available. We demonstrate the effectiveness of a simple interactive paradigm for obtaining a segmented object boundary, and show how a shape-based image matching algorithm can use the object outline to find similar images on the web.

  • 1158150. Yeh, Tom
    et al.
    Tollmar, Konrad
    Darrell, Trevor
    IDeixis: image-based Deixis for finding location-based information2004In: CHI ’04 extended abstracts on Human factors in computing systems, 2004, p. 781-782Conference paper (Refereed)
    Abstract [en]

    We demonstrate an image-based approach to specifying location and finding location-based information from camera-equipped mobile devices. We introduce a point-by-photograph paradigm, where users can specify a location simply by taking pictures. Our technique uses content-based image retrieval methods to search the web or other databases for matching images and their source pages to find relevant location-based information. In contrast to conventional approaches to location detection, our method can refer to distant locations and does not require any physical infrastructure beyond mobile internet service. We have developed a prototype on a camera phone and conducted user studies to demonstrate the efficacy of our approach compared to other alternatives.

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