873 resultados para Concept drift


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In this paper, the concept for a radio frequency identification (RFID) enabled student workbook is discussed and a prototype system developed. The workbook is a question-answer notebook in traditional paper format in which hand written solutions to student assignments are written. An embedded RFID tag in the workbook is then used for the student to store his/her solution to the attempted assignment questions at home. On entry to the classroom and once the questions have been attempted, an RFID reader in the classroom will retrieve the answers from the workbook, automatically collate the results and instantly provide a summary of these results for the individual student and the class as a whole. If problems are highlighted, the teacher can then investigate issues with individual students and review the answers provided in the workbook.

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The purpose of this review is to estimate the prevalence of peri-implantitis, as well as to determine possible risk factors associated with its development in patients treated with oral implants. Although implant therapy has been identified as a successful and predictable treatment for partially and fully edentulous patients, complications and failures can occur. Peri-implantitis is considered a biologic complication that results in bone loss around implants and may lead to implant treatment failure. A great variation has been observed in the literature regarding the prevalence of peri-implantitis according to the diagnostic criteria used to define peri-implantitis. The prevalence ranges from 4.7 to 43% at implant level, and from 8.9 to > 56% at patient level. Many risk factors that may lead to the establishment and progression of peri-implantitis have been suggested. There is strong evidence that presence and history of periodontitis are potential risk factors for peri-implantitis. Cigarette smoking has not yet been conclusively established as a risk factor for peri-implantitis, although extra care should be taken with dental implant in smokers. Other risk factors, such as diabetes, genetic traits, implant surface roughness and presence of keratinized mucosa still require further investigation. Peri-implantitis is not an uncommon complication following implant therapy. A higher prevalence of peri-implantitis has been identified for patients with presence or history of periodontal disease and for smokers. Until now, a true risk factor for peri-implantitis has not been established. Supportive maintenance program is essential for the long-term success of treatments with oral implants. The knowledge of the real impact of peri-implantitis on the outcome of treatments with oral implants as well as the identification of risk factors associated to this inflammatory condition are essential for the development of supportive maintenance programs and the establishment of prevention protocols.

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Increase in lower anterior crowding is a general problem among adult Caucasians. The tooth movement responsible for this phenomenon, however, is not fully elucidated. Aim of this study was to describe signs of ongoing tooth movement reflected in the thickness of the bundle bone around mandibular teeth and the distribution of eroding surfaces of the alveolar wall in human autopsy material. The distribution of bundle bone and eroding surfaces was assessed histomorphometrically on 106 mandibular teeth, and the surrounding bone obtained at autopsy from 35 deceased persons ranging from 19 to 55 years of age. By examining the mesio-distal and bucco-lingual aspects at the cervical and apical levels of the roots, a pattern of tooth movements could be established. The distribution of the bundle bone thickness and the vectors of eroding surfaces enabled the direction of tooth movement to be reconstructed. Mesial and lingual displacement was prevalent for the anterior teeth. The signs of ongoing displacement of lower teeth support the concept of crowding occurring in adult individuals and support the maintenance of retainers, even following cessation of growth.

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During the last decade, leaf tatters has been reported in white oak and hackberry across several Midwestern states. Herbicide spray drift studies have shown that chloroacetamides can induce leaf tatters. The objectives of this research were to: 1) identify vulnerable bud developmental stages in hackberry and 2) determine if different commercial chloroacetamides affect severity of leaf tatters. In 2008, a preliminary spray drift experiment was conducted on mature trees from a former hackberry provenance test stand. Acetochlor (Harness), S-metolachlor (Dual II Magnum), and dimethenamid (Outlook) were applied at concentrations approximating 27%, 54%, 81%, or 108% of the recommended field rate. Three developmental stages before bud burst were present on the selected trees. Leaf tatters did not develop on the selected hackberry trees. However, symptoms were observed on neighboring, non-target hackberry trees, which had been in the leaf unfolding and expanding stages at the time of spraying. In 2009, three year old hackberry seedlings were treated with 1%, 10%, and 100% of the recommended field rate of acetochlor (Harness), S-metolachlor (Dual II Magnum), and dimethenamid (Outlook). Folded buds and two unfolding leaf developmental stages were present on seedlings. Another spray study was conducted on 32 mature hackberry trees from the provenance stand. A solution of 5608 mg a.i./L dimethenamid (Outlook) was applied to trees in the unfolding and/or expanding leaf stage. Treated trees represented four provenances. Image analysis was used to calculate seedling and mature tree leaf areas and estimate the seedling percentage of leaf tissue loss. Foliar damage was not significantly different between seedlings treated with water, 1%, or 10% of the field rate. Foliar damage was significantly different between seedlings treated with 1% or 100% of the field rate, and between seedlings treated with 10% or 100% of the field rate. Foliar damage in seedlings was not significantly different between the developmental stages. Additionally, symptoms of leaf tatters were observed on the treated mature hackberry. Future studies should focus on chloroacetamide concentrations above 10% of the recommended field rate.

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ACID-BASE REACTIONS: CONCEPT, REPRESENTATION AND GENERALIZATION FROM THE ENERGY INVOLVED IN TRANSFORMATIONS. Undergraduate students on the first year of Chemistry Courses are unfamiliar with the representation of acid-base reactions using the ionic equation H+ + OH- -> H2O. A chemistry class was proposed about acid-base reactions using theory and experimental evaluation of neutralization heat to discuss the energy involved when water is formed from H+ and OH- ions. The experiment is suggested using different strong acids and strong base pairs. The presentation of the theme within a chemistry class for high school teachers increased the number of individuals that saw the acid-base reaction from this perspective.

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Purpose: This prospective randomized matched-pair controlled trial aimed to evaluate marginal bone levels and soft tissue alterations at implants restored according to the platform-switching concept with a new inward-inclined platform and compare them with external-hexagon implants. Materials and Methods: Traditional external-hexagon (control group) implants and inward-inclined platform implants (test group), all with the same implant body geometry and 13 mm in length, were inserted in a standardized manner in the posterior maxillae of 40 patients. Radiographic bone levels were measured by two independent examiners after 6, 12, and 18 months of prosthetic loading. Buccal soft tissue height was measured at the time of abutment connection and 18 months later. Results: After 18 months of loading, all 80 implants were clinically osseointegrated in the 40 participating patients. Radiographic evaluation showed mean bone losses of 0.5 +/- 0.1 mm (range, 0.3 to 0.7 mm) and 1.6 +/- 0.3 mm (range, 1.1 to 2.2 mm) for test and control implants, respectively. Soft tissue height showed a significant mean decrease of 2.4 mm in the control group, compared to 0.6 mm around the test implants. Conclusions: After 18 months, significantly greater bone loss was observed at implants restored according to the conventional external-hexagon protocol compared to the platform-switching concept. In addition, decreased soft tissue height was associated with the external-hexagon implants versus the platform-switched implants. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:927-934.

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BACKGROUND: Genetically modified MON 87701 X MON 89788 soybean (Glycine max), which expresses the Cry1Ac and EPSP-synthase proteins, has been registered for commercial use in Brazil. To develop an Insect Resistance Management (IRM) program for this event, laboratory and field studies were conducted to assess the high-dose concept and level of control it provides against Anticarsia gemmatalis and Pseudoplusia includens. RESULTS: The purified Cry1Ac protein was more active against A. gemmatalis [LC50 (FL 95%) = 0.23 (0.150.34) mu g Cry1Ac mL-1 diet] than P. includens [LC50 (FL 95%) = 3.72 (2.654.86) mu g Cry1Ac mL-1 diet]. In bioassays with freeze-dried MON 87701X MON 89788 soybean tissue diluted 25 times in an artificial diet, there was 100% mortality of A. gemmatalis and up to 95.79% mortality for P. includens. In leaf-disc bioassays and under conditions of high artificial infestation in the greenhouse and natural infestation in the field, MON 87701X MON 89788 soybean showed a high level of efficacy against both target pests. CONCLUSIONS: The MON 87701X MON 89788 soybean provides a high level of control against A. gemmatalis and P. includes, but a high-dose event only to A. gemmatalis. Copyright (c) 2012 Society of Chemical Industry

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The layer-by-layer (LbL) technique combined with field-effect transistor (FET) based sensors has enabled the production of pH-sensitive platforms with potential application in biosensors. A variation of the FET architecture, so called separative extended gate FET (SEGFET) devices, are promise as an alternative to conventional ion sensitive FET (ISFET). SEGFET configuration exhibits the advantage of combining the field-effect concept with organic and inorganic materials directly adsorbed on the extended gate, allowing the test of new pH-sensitive materials in a simple and low cost way. In this communication, poly(propylene imine) dendrimer (PPI) and TiO2 nanoparticles (TiO2-np) were assembled onto gold-covered substrates via layer-by-layer technique to produce a low cost SEGFET pH sensor. The sensor presented good pH sensitivity, ca. 57 mV pH(-1), showing that our strategy has potential advantages to fabricate low cost pH-sensing membranes. (C) 2012 Elsevier B.V. All rights reserved.

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We consider modifications of the nonlinear Schrodinger model (NLS) to look at the recently introduced concept of quasi-integrability. We show that such models possess an in finite number of quasi-conserved charges which present intriguing properties in relation to very specific space-time parity transformations. For the case of two-soliton solutions where the fields are eigenstates of this parity, those charges are asymptotically conserved in the scattering process of the solitons. Even though the charges vary in time their values in the far past and the far future are the same. Such results are obtained through analytical and numerical methods, and employ adaptations of algebraic techniques used in integrable field theories. Our findings may have important consequences on the applications of these models in several areas of non-linear science. We make a detailed numerical study of the modified NLS potential of the form V similar to (vertical bar psi vertical bar(2))(2+epsilon), with epsilon being a perturbation parameter. We perform numerical simulations of the scattering of solitons for this model and find a good agreement with the results predicted by the analytical considerations. Our paper shows that the quasi-integrability concepts recently proposed in the context of modifications of the sine-Gordon model remain valid for perturbations of the NLS model.

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Supply chain starts with a demand arisen and ends with material transport and delivery at its final destination. With this in mind, most of manufacturing, processors or distribution companies of consumer goods, spare parts and components for production, processing and finished goods, within national or international markets, may not have information and control over its supply chain performance. This article presents concept and logistics models evolution, purchase order and international supplier management, control tower and its logistics information systems. This also presents a real process implementation for a global high tech manufacturer company.

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The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project.