1,395 research outputs found

    Stability analysis of coupled map lattices at locally unstable fixed points

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    Numerical simulations of coupled map lattices (CMLs) and other complex model systems show an enormous phenomenological variety that is difficult to classify and understand. It is therefore desirable to establish analytical tools for exploring fundamental features of CMLs, such as their stability properties. Since CMLs can be considered as graphs, we apply methods of spectral graph theory to analyze their stability at locally unstable fixed points for different updating rules, different coupling scenarios, and different types of neighborhoods. Numerical studies are found to be in excellent agreement with our theoretical results.Comment: 22 pages, 6 figures, accepted for publication in European Physical Journal

    XML Reconstruction View Selection in XML Databases: Complexity Analysis and Approximation Scheme

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    Query evaluation in an XML database requires reconstructing XML subtrees rooted at nodes found by an XML query. Since XML subtree reconstruction can be expensive, one approach to improve query response time is to use reconstruction views - materialized XML subtrees of an XML document, whose nodes are frequently accessed by XML queries. For this approach to be efficient, the principal requirement is a framework for view selection. In this work, we are the first to formalize and study the problem of XML reconstruction view selection. The input is a tree TT, in which every node ii has a size cic_i and profit pip_i, and the size limitation CC. The target is to find a subset of subtrees rooted at nodes i1,,iki_1,\cdots, i_k respectively such that ci1++cikCc_{i_1}+\cdots +c_{i_k}\le C, and pi1++pikp_{i_1}+\cdots +p_{i_k} is maximal. Furthermore, there is no overlap between any two subtrees selected in the solution. We prove that this problem is NP-hard and present a fully polynomial-time approximation scheme (FPTAS) as a solution

    Countering the Service-Learning Privilege Problem Through Critical Communication Pedagogy and Critical Assessment

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    Because the communication discipline values action, civility, and service, it has placed emphasis on the integration of service-learning in its courses. Service-learning has the potential to bridge the gap between the classroom and the community by employing social justice pedagogy–activism that takes critical learning to sites of hegemony. However, service-learning can also promote the unintended side effect of entrenching beliefs about privilege. Therefore, we advocate for a critical service-learning to be facilitated through a critical communication pedagogy (CCP) framework, which emphasizes the recognition and response to hegemony that students encounter. Such an approach employs critical assessment, a means by which to reframe traditional assessment procedures to focus on both content knowledge and its application to ameliorate hegemony in society

    "Playstation eyetoy games" improve upper extremity-related motor functioning in subacute stroke:a randomized controlled clinical trial

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    Aim. To evaluate the effects of "Playstation EyeToy Games" on upper extremity motor recovery and upper extremity-related motor functioning of patients with subacute stroke. Methods. The authors designed a randomized, controlled, assessor-blinded, 4-week trial, with follow-up at 3 months. A total of 20 hemiparetic inpatients (mean age 61.1 years), all within 12 months post-stroke, received 30 minutes of treatment with "Playstation EyeToy Games" per day, consisting of flexion and extension of the paretic shoulder, elbow and wrist as well as abduction of the paretic shoulder or placebo therapy (watching the games for the same duration without physical involvement into the games) in addition to conventional program, 5 days a week, 2-5 hours/day for 4 weeks. Brunnstrom's staging and self-care subitems of the functional independence measure (FIM) were performed at 0 month (baseline), 4 weeks (post-treatment), and 3 months (follow-up) after the treatment. Results. The mean change score (95% confidence interval) of the FIM self-care score (5.5 [2.9-8.0] vs 1.8 [0.1-3.7], P=0.018) showed significantly more improvement in the EyeToy group compared to the control group. No significant differences were found between the groups for the Brunnstrom stages for hand and upper extremity. Conclusion. "Playstation EyeToy Games" combined with a conventional stroke rehabilitation program have a potential to enhance upper extremity-related motor functioning in subacute stroke patients.</div

    Sodium Glucose Cotransporter-2 (SGLT-2) Inhibitor Related Diabetic Ketoacidosis

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    Diabetic ketoacidosis is a rare but serious and life-threatening acute complication of diabetes mellitus. It is characterized by ketoacidosis with other findings and should be treated immediately. In this case, a 33-year-old diabetic patient who admitted to the emergency department with diabetic ketoacidosis is presented. The patient was prescribed empagliflozin (sodium glucose cotransporter inhibitor-2) a month ago. The SGLT-2 inhibitors have been approved for use in the treatment of type 2 DM and are still not used in the treatment of type 1 DM. There are such reports of unusual side effects related SGLT-2 inhibitors, in the literature and among them, ketoacidosis is a rare and important side effect

    Дослідження мотиваційних чинників професійного становлення вчителя

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    This paper studies two-hop cooperative demodulate-and-forward relaying using multiple relays in wireless networks. A threshold based relay selection scheme is considered, in which the reliable relays are determined by comparing source-relay SNR to a threshold, and one of the reliable relays is selected by the destination based on relay-destination SNR. The exact bit error rate of this scheme is derived, and a simple threshold function is proposed. It is shown that the network achieves full diversity order (N +1) under the proposed threshold, where N is the number of relays in the network. Unlike some other full diversity achieving protocols in the literature, the requirement that the instantaneous/average SNRs of the source-relay links be known at the destination is eliminated using the appropriate SNR threshold

    Spectral plots and the representation and interpretation of biological data

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    It is basic question in biology and other fields to identify the char- acteristic properties that on one hand are shared by structures from a particular realm, like gene regulation, protein-protein interaction or neu- ral networks or foodwebs, and that on the other hand distinguish them from other structures. We introduce and apply a general method, based on the spectrum of the normalized graph Laplacian, that yields repre- sentations, the spectral plots, that allow us to find and visualize such properties systematically. We present such visualizations for a wide range of biological networks and compare them with those for networks derived from theoretical schemes. The differences that we find are quite striking and suggest that the search for universal properties of biological networks should be complemented by an understanding of more specific features of biological organization principles at different scales.Comment: 15 pages, 7 figure

    Concave Plasmonic Particles: Broad-Band Geometrical Tunability in the Near Infra-Red

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    Optical resonances spanning the Near and Short Infra-Red spectral regime were exhibited experimentally by arrays of plasmonic nano-particles with concave cross-section. The concavity of the particle was shown to be the key ingredient for enabling the broad band tunability of the resonance frequency, even for particles with dimensional aspect ratios of order unity. The atypical flexibility of setting the resonance wavelength is shown to stem from a unique interplay of local geometry with surface charge distributions

    Validity and reliability of the Clinical Learning Environment, Supervision and Nurse Teacher (CLES plus T), Turkish version

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    Aim: A methodological type of study was conducted for the purpose of investigating the validity and reliability of the Turkish version of the Clinical Learning Environment, Supervision and Nurse Teacher (CLES+T) evaluation scale of the clinical learning environment of students, clinical nurses, and educators. Methods: Sample was comprised of 602 Turkish nursing students with clinical practice experience at the hospital. The CLES+T, developed by Saarikoski, was used for data collection. Language equivalency, internal consistency, item-total correlation, and structure validity were conducted within the scope of the validity and reliability study on the CLES +T scale. Results: It was determined that item-total correlations of four items were lower than 0.30, and those items were removed from the scale as a result of item analysis. The Cronbach's alpha value of the scale was 0.93-0.99; item total point correlations of the scale varied between 0.45 and 0.66; six factors were identified in the CLES+T factor analysis study, with a total variance explained by these six factors of 64%. Conclusion: According to the findings of the research, the CLES+T Turkish version was found to be a valid and reliable scale, which can be used to evaluate satisfaction of nursing students with their clinical education in Turkey

    Investigations of Ti Binary Alloys Manufactured by Powder Metallurgy for Biomaterial Applications

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    [EN] Biomaterials encompass synthetic alternatives to the native materials found in our body. They have shown rapid growth in the field of elderly population demands with the prolongation of human life. Titanium is one of the biomaterials with excellent properties and biocompatibility. However, its high stiffness may cause weakening in the structures. To sort out this problem, Ti-Cr, Ti-Mo, and Ti-Cu alloys were produced by powder metallurgy. Metal powders were mixed by mechanical alloying. After pressing and sintering, characterizations were carried out by scanning electron microscopy, X-ray diffraction, electron backscattering diffraction, and three points bending test.The authors thank the Ministerio de Economia y Competitividad of Spain for the research project MAT2014-53764-C3-1-R, An European Commission by FEDER funds for the purchase of equipment, the Generalitat Valenciana by the PROMETEO/2016/040 project.Atay, HY.; Rodríguez, M.; Amigó Mata, A.; Vicente-Escuder, Á.; Amigó, V. (2018). Investigations of Ti Binary Alloys Manufactured by Powder Metallurgy for Biomaterial Applications. Acta Physica Polonica A. 134(1):415-418. https://doi.org/10.12693/APhysPolA.134.415S415418134
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