1,299 research outputs found

    Heuristic algorithm for determination of local properties of scale-free networks

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    Complex networks are everywhere. Many phenomena in nature can be modeled as networks: - brain structures - protein-protein interaction networks - social interactions - the Internet and WWW. They can be represented in terms of nodes and edges connecting them. Important characteristics: - these networks are not random; they have a structured architecture. Structure of different networks are similar: - all have power law degree distribution (scale-free property) - despite large size there is usually relatively short path between any two nodes (small world property). Global characteristics: - degree distribution, clustering coefficient and the diameter. Local structure: - frequency of subgraphs of given type (subgraph of order k is a part of the network consisting of k nodes and edges between them). There are different types of subgraphs of the same order

    Three-dimensional dispersion induced by extreme tensile strain in La_(2–x)Sr_xCuO_4 films

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    The electronic band structure probed by angle-resolved photoemission spectroscopy on thin epitaxial La2–xSrxCuO4 films under extreme tensile strain shows anomalous features compatible with c-axis dispersion. This result is in striking contrast with the usual quasi-two-dimensional (2D) dispersion observed up to now in most superconducting cuprates, including relaxed and compressively strained La2–xSrxCuO4 films grown under the same conditions. The data were analyzed using a 3D tight-binding dispersion for a body-centered-tetragonal lattice. We relate the enhancement of the c-axis dispersion to the significant displacement of the apical oxygen induced by epitaxial strain

    Concept tagging in Moodle

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    The Moodle learning management system (LMS) is becoming increasingly widespread due to its adoption by education providers at all levels. The system however does not provide educators with the ability to create connections between online course material and domain concepts easily and visibly. We chose concept tagging as the method for allowing teachers to provide these links in a new concept tags plug-in for Moodle. Our concept tagging plug-in allows the creation, management and application of concept tags to course content. Students and teachers will mutually benefit from the use of such a mechanism, as it would aid information location in and retrieval from course content. An initial evaluation of the plug-in showed that teachers find the concept tagging of course modules to be a desirable and usable functionality that Moodle lacks. The work in this paper describes the first prototype of the plug-in, the aim of which is provide the first step in contributing to the addition of basic student modelling functionality to Moodle as part of a wider project. By continually keeping track of a student’s progress on each concept tag, Moodle will be able to suggest appropriate course modules for further study based on this progress

    Data-driven misconception discovery in constraint-based intelligent tutoring systems

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    Students often have misconceptions in the domain they are studying. Misconception identification is a difficult task but allows teachers to create strategies to appropriately address misconceptions held by students. This project investigates a data-driven technique to discover students' misconceptions in interactions with constraint-based Intelligent Tutoring Systems(ITSs). This analysis has not previously been done. EER-Tutor is one such constraint-based ITS, which teaches conceptual database design using Enhanced Entity-Relationship (EER) data modelling. As with any ITS, a lot of data about each student's interaction within EER-Tutor are available: as individual student models, containing constraint histories, and logs, containing detailed information about each student action. This work can be extended to other ITSs and their relevant domains

    Implementation of triticale in nutrition of non-ruminant animals

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    Cognition of chemical composition and nutritive values of triticale grain as well as the effect of its application in non-ruminant animal nutrition were pointed out in this paper. There is a high level of proteins in the grain of triticale (2 to 3% more than wheat and 4% more than rye), with very beneficial amino acid composition, and is the reason for its usage in domestic animals nutrition. Nowadays, people are of the opinion that triticale is one of potential plant species with the brightest perspective in the production of food for domestic animals. Considering the increased production of triticale, some detail researching of its nutritional value is necessary due to the required evaluation of the role and significance in domestic animal nutrition based on triticale. Due to intensive plant breeding programs, there are new varieties of triticale in the market, distinctive by the higher yield and wide range of desired traits. As a result of this, triticale is becoming very attractive and is occupying larger portions of arable land. These review will show if there are some advantages of triticale compared to other cereals and how large the frame of these advantages is, as well as how it will affect the further spreading of triticale on arable land.Key words: Triticale, chemical composition, nutritive capacity, nutrition

    Interpretation of the Friction Coefficient During Reciprocating Sliding of Ti6Al4V Alloy Against Al2O3

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    Tribological behaviour of Ti6Al4V alloy, during linear reciprocating sliding against alumina, at nanotribometer (ball-on-flat type of contact) was investigated. Experiments were carried out for sliding in Ringer's solution, over a range of loads (100 - 1000 mN) and speeds (4 - 12 mm/s). Friction behaviour of the contact pairs was investigated by analysis of the dynamic friction coefficient plots and effective root mean square (rms) coefficient of friction, COFrms. Presented mathematical envelopes of dynamic coefficient of friction curves and averaged envelope signals provided additional explanation of one calculated COFrms value. Envelopes of dynamic coefficient of friction enabled easier determination of different periods during sliding, which were further related to wear mechanisms

    The e!ects of a non-intervention HACCP implementation on process hygiene indicators on bovine and porcine carcasses

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    Four sites on each of 720 dressed carcasses (360 bovine and 360 porcine) were sampled (2,880 samples in total) in a single commercial abattoir slaughtering cattle and pigs using two separate slaughterlines. The carcasses were sampled before HACCP (pre-HACCP; 960 samples) and after HACCP implementation (post-HACCP; 1,920 samples) and Total Viable Count (TVC), Enterobacteriaceae count (EC) and Salmonella spp. prevalence were determined. During the pre-HACCP period, mean TVC levels on four tested sites varied on bovine carcasses between 3.03 and 4.19 log10 cfu/cm2 and on porcine carcasses between 3.73 and 3.99 log10 cfu/cm2. During the post-HACCP period, TVC levels on all tested sites on carcasses were further signicantly reduced, by 0.33-1.64 log and 1.13-2.04 log on bovine and porcine carcasses, respectively, compared to the pre-HACCP period. Both the EC occurrence in samples and EC levels in EC-positive samples somewhat decreased during post-HACCP as compared to pre-HACCP period, but the reductions were not statistically signicant due to large proportion of EC-negative samples and very low counts in EC-positive samples. Salmonella spp. was not detected in any of bovine or porcine carcass samples, regardless of whether they were taken pre- or post-HACCP. Overall, the processhygiene- improving eects of non-intervention HACCP have been proven through reduction of TVC on carcasses, but could not be veried in the present study through similar reductions in EC and/or Salmonella, because of their low levels and/or absence

    Graft-take Success in Walnut Under Controlled Conditions and Plant Development in the Nursery

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    The production of walnut nursery plants is a complex process, being dependent upon a range of factors that affect graft-take success and behaviour of walnut plants in the nursery. The experiment included two parts. Three different treatments were used in the heated room under controlled air temperature and humidity conditions: Treatment 1-grafting without paraffin treatment of the scion and graft union, coupled with covering the graft with sawdust up to the top of the scion; Treatment 2-grafting involving paraffin treatment of the scion and graft union, coupled with covering the graft with sawdust up to the top of the scion; and Treatment 3-grafting involving paraffin treatment of the scion and graft union, coupled with covering the graft with both sawdust up to the top of the scion and polyethylene foil. The treatments were evaluated for their effect on graft-take success. Graft planting in the nursery was followed by two treatments: treatment without foliar fertilisation and treatment with foliar fertilisation. Under controlled conditions, treatment 3 induced a higher graft-take success as compared to the other two treatments, whereas foliar fertilisation in the nursery had a positive effect on the survival, production of class 1 plants and vegetative growth of walnut plants

    Microindentation of Polymethyl Methacrylate (PMMA) Based Bone Cement

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    Characterization of polymethyl methacrylate (PMMA) based bone cement subjected to cyclical loading using microindentation technique is presented in this paper. Indentation technique represents flexible mechanical testing due to its simplicity, minimal specimen preparation and short time needed for tests. The mechanical response of bone cement samples was studied. Realised microindentation enabled determination of the indentation testing hardness HIT and indentation modulus EIT of the observed bone cement. Analysis of optical photographs of the imprints showed that this technique can be effectively used for characterization of bone cements
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