993 resultados para Centers and Museums of Sciences


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Mode of access: Internet.

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"A revision and enlargement of Bulletin 226...was...issued in 1923 as Bulletin 689. The present bulletin is a revision and enlargement of the 1923 edition"--Foreword, p. vii.

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In the present paper, it is presented a general view about who they are and the activities science centers and museums mediators develop. The literature points out to the diverse roles attributed to these actors and that the presence of this type of professional is a consolidated practice in non-formal educational institutions. Data obtained among the mediators of a science center during mediated school visits are also presented and discussed, focusing in the role attributed to these professionals, with the objective of characterizing their actions during these visits. The data obtained and analyzed showed that during school visits, the roles that are attributed to the mediators are: (a) mediation of the knowledge involved in the expositions; (b) explanation of the scientific concepts involved in the expositions; (c) presentation of the thematic spaces; (d) reception and organization of groups of visitors; (e) preservation of the physical and moral integrity of the visitors, and the integrity of the physical spaces and their equipments; (f) complementation of the school knowledge, and (g) diffusion of the scientific knowledge.

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Diamant ist ein Material mit vielen außerordentlichen Eigenschaften, die ihn zu einem äußerst vielversprechenden Kandidaten für Anwendungen in Wissen-schaft und Technik machen. In den letzten Jahren wurde Diamant häufig als einzigartige Plattform für neue Anwendungen beispielsweise in der Quanteninformationstechnologie (QIT) oder in der Magnetometrie im Nanometermaßstab eingesetzt, wobei einer der wichtigsten lumineszierenden Gitterdefekte im Diamantgitter eingesetzt wird. Dabei handelt es sich um die sogenannten Stickstoff/Fehlenstellen-Farbzentren (NV-Zentren), die im sichtbaren Bereich mit einer absoluten Photostabilität bei Raumtemperatur emittieren. In dieser Arbeit wurden NV-Zentren in Diamantnanokristalliten und –nanosäulen untersucht, die während des Wachstumsprozesses erzeugt wurden. Einzelne Diamantnanokristallite und nanokristalline Diamantschichten (NCD), aus denen Nanosäulen geätzt wurden, wurden mithilfe der Hot Filament Chemical Vapour Deposition (HFCVD) abgeschieden. Zu Vergleichszwecken wurden auch ultrananokristalline Diamantschichten (UNCD) mittels Mikrowellen-CVD (MWCVD) hergestellt. Die Filme wurden sorgfältig in Bezug auf ihre Morphologie, kristallinen Eigenschaften und Zusammensetzung untersucht. Um die Möglichkeit einer Integration dieser Diamantschichten mit temperaturempfindlichen Materialien wie III/V-Halbleitern, Metallen mit niedrigem Schmelzpunkt oder Polymeren zu untersuchen, wurde der Einfluss der Substrattemperatur ermittelt. Eindimensionale NCD- und UNCD-Diamantnanostrukturen wurden mithilfe der Elektronenstrahllithographie (EBL) und reaktivem Ionenätzen in einem induktiv gekoppelten O2-Plasma (ICP-RIE) hergestellt. Zur Vorbereitung wurden zunächst die Ätzraten in Abhängigkeit von den vier wichtigsten Parametern ermittelt. Weitere Erkenntnisse über die Ätzmechanismen wurden durch Ätzexperiment mit unstrukturierten NCD- und UNCD-Schichten erhalten Mittels der EBL konnten mithilfe von Gold-Ätzmasken Nanosäulen mit Durchmessern von 50 nm bis zu 1 μm hergestellt werden.Eine optische Charakterisierung der NCD- und UNCD-Nanosäulen erfolgte mithilfe von Fluorenzenz-Mapping und Photomumineszenz-Spektroskopie. Diese Messungen ergaben, dass in beiden Arten von Säulen NV-Zentren vorhanden sind. Allerdings wurden nur in NCD-Säulen die gewünschten NV--Zentren gefunden, in UNCD-Säulen hingegen nur NV0-Zentren.

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The proteasome is responsible for degradation of substrates of the ubiquitin pathway. 20S proteasomes are cylindrical particles with subunits arranged in a stack of four heptameric rings. The outer rings are composed of α subunits, and the inner rings are composed of β subunits. A well-characterized archaeal proteasome has a single type of each subunit, and the N-terminal threonine of the β subunit is the active-site nucleophile. Yeast proteasomes have seven different β subunits and exhibit several distinct peptidase activities, which were proposed to derive from disparate active sites. We show that mutating the N-terminal threonine in the yeast Pup1 β subunit eliminates cleavage after basic residues in peptide substrates, and mutating the corresponding threonine of Pre3 prevents cleavage after acidic residues. Surprisingly, neither mutation has a strong effect on cell growth, and they have at most minor effects on ubiquitin-dependent proteolysis. We show that Pup1 interacts with Pup3 in each β subunit ring. Our data reveal that different proteasome active sites contribute very differently to protein breakdown in vivo, that contacts between particular subunits in each β subunit ring are critical for active-site formation, and that active sites in archaea and different eukaryotes are highly similar.

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Mode of access: Internet.

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Visiting a modern shopping center is becoming vital in our society nowadays. The fast growth of shopping center, transportation system, and modern vehicles has given more choices for consumers in shopping. Although there are many reasons for the consumers in visiting the shopping center, the influence of travel time and size of shopping center are important things to be considered towards the frequencies of visiting customers in shopping centers. A survey to the customers of three major shopping centers in Surabaya has been conducted to evaluate the Ellwood’s model and Huff’s model. A new exponent value N of 0.48 and n of 0.50 has been found from the Ellwood’s model, while a coefficient of 0.267 and an add value of 0.245 have been found from the Huff’s model.

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Educational reforms currently being enacted in Kuwaiti Family and Consumer Sciences (FCS) in response to contemporary demands for increased student-centred teaching and learning are challenging for FCS teachers due to their limited experience with student-centred learning tools such as Graphic Organisers (GOs). To adopt these reforms, Kuwaiti teachers require a better understanding of and competency in promoting cognitive learning processes that will maximise student-centred learning approaches. This study followed the experiences of four Grade 6 FCS Kuwaiti teachers as they undertook a Professional Development (PD) program specifically designed to advance their understanding of the use of GOs and then as they implemented what they had learned in their Grade 6 FCS classroom. The PD program developed for this study was informed by Nasseh.s competency PD model as well as Piaget and Ausubel.s cognitive theories. This model enabled an assessment and evaluation of the development of the teachers. competencies as an outcome of the PD program in terms of the adoption of GOs, in particular, and their capacity to use GOs to engage students in personalised, in-depth, learning through critical thinking and understanding. The research revealed that the PD program was influential in reforming the teachers. learning, understanding of and competency in, cognitive and visual theories of learning, so that they facilitated student-centred teaching and learning processes that enabled students to adopt and adapt GOs in constructivist learning. The implementation of five GOs - Flow Chart, Concept Maps, K-W-L Chart, Fishbone Diagram and Venn Diagram - as learning tools in classrooms was investigated to find if changes in pedagogical approach for supporting conceptual learning through cognitive information processing would reduce the cognitive work load of students and produce better learning approaches. The study as evidenced by the participant teachers. responses and classroom observations, showed a marked increase in student interest, participation, critical thought, problem solving skills, as a result of using GOs, compared to using traditional teaching and learning methods. A theoretical model was developed from the study based on the premise that teachers. knowledge of the subject, pedagogy and student learning precede the implementation of student-centred learning reform, that it plays an important role in the implementation of student-centred learning and that it brings about a change in teaching practice. The model affirmed that observed change in teaching-practice included aspects of teachers. beliefs, as well as confidence and effect on workplace and on student learning, including engagement, understanding, critical thinking and problem solving. The model assumed that change in teaching practice is inseparable from teachers. lifelong PD needs related to knowledge, understanding, skills and competency. These findings produced a set of preliminary guidelines for establishing student-centred constructivist strategies in Kuwaiti education while retaining Kuwait.s cultural uniqueness.

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This paper reports a number of findings from the Interests and Recruitment in Science (IRIS) study carried out in Australia in 2011. The findings concern the perceptions of first year university students in science, technology and engineering courses about the influence of museums/science centres and outreach activities on their choice of course. The study found that STE students in general tended to rate museums/science centres as more important in their decisions than outreach activities. However, a closer examination showed that females in engineering courses were significantly more inclined to rate outreach activities as important than were males in engineering courses or females in other courses. The implications of this finding for strategies to encourage more young women into engineering are discussed.

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We identified, mapped, and characterized a widespread area (gt;1,020 km2) of patterned ground in the Saginaw Lowlands of Michigan, a wet, flat plain composed of waterlain tills, lacustrine deposits, or both. The polygonal patterned ground is interpreted as a possible relict permafrost feature, formed in the Late Wisconsin when this area was proximal to the Laurentide ice sheet. Cold-air drainage off the ice sheet might have pooled in the Saginaw Lowlands, which sloped toward the ice margin, possibly creating widespread but short-lived permafrost on this glacial lake plain. The majority of the polygons occur between the Glacial Lake Warren strandline (~14.8 cal. ka) and the shoreline of Glacial Lake Elkton (~14.3 cal. ka), providing a relative age bracket for the patterned ground. Most of the polygons formed in dense, wet, silt loam soils on flat-lying sites and take the form of reticulate nets with polygon long axes of 150 to 160 m and short axes of 60 to 90 m. Interpolygon swales, often shown as dark curvilinears on aerial photographs, are typically slightly lower than are the polygon centers they bound. Some portions of these interpolygon swales are infilled with gravel-free, sandy loam sediments. The subtle morphology and sedimentological characteristics of the patterned ground in the Saginaw Lowlands suggest that thermokarst erosion, rather than ice-wedge replacement, was the dominant geomorphic process associated with the degradation of the Late-Wisconsin permafrost in the study area and, therefore, was primarily responsible for the soil patterns seen there today.

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The aim of the study was to assess the feasibility and effectiveness of aquatic‐based exercise in the form of deep water running ( DWR ) as part of a multimodal physiotherapy programme ( MMPP ) for breast cancer survivors. A controlled clinical trial was conducted in 42 primary breast cancer survivors recruited from community‐based P rimary C are C entres. Patients in the experimental group received a MMPP incorporating DWR , 3 times a week, for an 8‐week period. The control group received a leaflet containing instructions to continue with normal activities. Statistically significant improvements and intergroup effect size were found for the experimental group for P iper F atigue S cale‐ R evised total score ( d = 0.7, P = 0.001), as well as behavioural/severity ( d = 0.6, P = 0.05), affective/meaning ( d = 1.0, P = 0.001) and sensory ( d = 0.3, P = 0.03) domains. Statistically significant differences between the experimental and control groups were also found for general health ( d = 0.5, P < 0.05) and quality of life ( d = 1.3, P < 0.05). All participants attended over 80% of sessions, with no major adverse events reported. The results of this study suggest MMPP incorporating DWR decreases cancer‐related fatigue and improves general health and quality of life in breast cancer survivors. Further, the high level of adherence and lack of adverse events indicate such a programme is safe and feasible.

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In the last thirty years, ethnic museums have mushroomed in American cities. Although this is certainly a national phenomenon, it has been particularly evident in Los Angeles. In this paper we examine the genesis and evolution of these emerging institutions. We survey the mission, scope, and role of ethnic museums in Los Angeles, and we contrast them with the stated mission and scope of “mainstream” museums in the city. We further present case studies of three Los Angeles ethnic museums. The museums vary considerably in the ways they perceive their role in the community, the city, and the nation and in the preservation and display of ethnic culture. At their best, ethnic museums serve to make new art and histories more accessible and visible and provide a forum in which to debate contemporary issues of politics and identity. The paper highlights some of the tensions faced by ethnic museums as they seek to define their audience and role(s) in multi-ethnic, twenty-first century Los Angeles.

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This paper describes the cost-benefit analysis of digital long-term preservation (LTP) that was carried out in the context of the Finnish National Digital Library Project (NDL) in 2010. The analysis was based on the assumption that as many as 200 archives, libraries, and museums will share an LTP system. The term ‘system’ shall be understood as encompassing not only information technology, but also human resources, organizational structures, policies and funding mechanisms. The cost analysis shows that an LTP system will incur, over the first 12 years, cumulative costs of €42 million, i.e. an average of €3.5 million per annum. Human resources and investments in information technology are the major cost factors. After the initial stages, the analysis predicts annual costs of circa €4 million. The analysis compared scenarios with and without a shared LTP system. The results indicate that a shared system will have remarkable benefits. At the development and implementation stages, a shared system shows an advantage of €30 million against the alternative scenario consisting of five independent LTP solutions. During the later stages, the advantage is estimated at €10 million per annum. The cumulative cost benefit over the first 12 years would amount to circa €100 million.

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The design and preparation of novel M3L2 trigonal cages via the coordination-driven self-assembly of preorganized metalloligands containing octahedral aluminum(III), gallium(III), or ruthenium(II) centers is described. When tritopic or dinuclear linear metalloligands and appropriate complementary subunits are employed, M3L2 trigonal-bipyramidal and trigonal-prismatic cages are self-assembled under mild conditions. These three-dimensional cages were characterized with multinuclear NMR spectroscopy (H-1 and P-31) and high-resolution electrospray ionization mass spectrometry. The structure of one such trigonal-prismatic cage, self-assembled from an arene ruthenium metalloligand, was confirmed via single-crystal X-ray crystallography. The fluorescent nature of these prisms, due to the presence of their electron-rich ethynyl functionalities, prompted photophysical studies, which revealed that electron-deficient nitroaromatics are effective quenchers of the cages' emission. Excited-state charge transfer from the prisms to the nitroaromatic substrates can be used as the basis for the development of selective and discriminatory turn-off fluorescent sensors for nitroaromatics.