Meanings given to algebraic symbolism in problem-posing     

María C. Cañadas  Marta Molina  Aurora del Río 《Educational Studies in Mathematics》2018,98(1):19-37

Some errors in the learning of algebra suggest that students might have difficulties giving meaning to algebraic symbolism. In this paper, we use problem posing to analyze the students’ capacity to assign meaning to algebraic symbolism and the difficulties that students encounter in this process, depending on the characteristics of the algebraic statements given. We designed a written questionnaire composed of eight closed algebraic statements expressed symbolically, which was administered to 55 students who had finished their compulsory education and who had some previous experience in problem-posing. In our analysis of the data, we examine both syntactic and semantic structures of the problem posed. We note that in most cases students posed problems with syntactic structures different to those given. They did not include computations within variables, and changed the kinds of relationships connecting variables. Students easily posed problems for statements with additive structures. Other differences in the type of problems posed depend on the characteristics of the given statements.  相似文献   

Understanding of graphs in social science undergraduate students: selection and interpretation of graphs     

Mª del Puy Pérez-Echeverría  Cristina Marín 《Irish Educational Studies》2018,37(1):89-111

How do university students understand the graphs that they read in their textbooks? How does their knowledge regarding the content and their statistical training influence this understanding? Does the kind of task demand also influence this understanding? To answer these questions, we asked a group of psychology students and a group of economics students to choose the most suitable graph for presenting the results of different psychological research studies (reports) (selection task) or to explain in words the results of the same reports shown by means of their graphic representations only (interpretation task). The results showed there were very few differences between groups. Most of the students were able to relate textual information to the adequate graph, but also revealed significant shortcomings and mistakes in their understanding of important syntactic aspects of graphs. They also interpreted the graphs correctly but their interpretation had different levels of complexity, which were not always optimal. We also identified significant differences regarding the difficulty of the reports and the kinds of misinterpretations of graphs. The two tasks thus revealed different pictures of students’ skills in reading and interpreting graphs and, consequently, how the characteristics of task demands influence their performance.  相似文献   

A virtual experience to strengthen students' understanding of inference in experimental design          下载免费PDF全文

María Virginia López  María del Carmen Fabrizio  María Cristina Plencovich 《Teaching Statistics》2018,40(3):88-93

Although our students correctly define the terms p‐value, Type I and Type II errors, they sometimes misinterpret results from real data. In this work we present an assignment intended to clear up these misconceptions.  相似文献   

Close, but not the same: Locally headquartered organizations and agglomeration economies in a declining industry     

Pino G. Audia  Christopher I. Rider 《Research Policy》2010,39(3):360-374

Departing from research on expanding, high-technology industries, we study the impact of agglomeration in a declining, low-technology industry. The setting is U.S. footwear manufacturing between 1975 and 1991, when import competition rendered local support critical for survival. We examine how agglomeration-related survival benefits depended upon the presence of locally headquartered manufacturing plants and whether such benefits came at the expense of other local industries. Consistent with ecological arguments, plant failure rates were higher in agglomerations but this effect was attenuated and, in some cases, reversed in agglomerations with more locally headquartered plants. Moreover, only locally headquartered plants experienced such benefits; remotely headquartered plants failed at higher rates in agglomerations. Although more footwear manufacturing jobs were retained in agglomerations with many locally headquartered plants, such locales also exhibited lower manufacturing job growth in other industries. These findings lend greater generalizability to agglomeration theories and also imply trade-offs at the community level.  相似文献   

THE LIBRARIES OF THE UNIVERSITY OF LISBON: CURRENT SITUATION     

Aires A. Nascimento  Maria Margarida Pino 《Higher Education in Europe》1989,14(4):43-52

The reduced budgetary appropriations that have been allocated to higher education are reflected in the management of the Portuguese university libraries. The organization of the libraries of the University of Lisbon is described, and certain deficiencies common to them and to the other Portuguese university libraries are pointed out, such as the lack of adequately trained professional staff members. Reference is made to the current state of computerization of the catalogues of collections and to the problems which have arisen as a result of the need to standardize procedures with regard to participation in the National Bibliographic Database ‐‐ PORBASE. The role of university libraries in their su rounding communities is stressed as well as the urgent need to find ways of overcoming the crisis situation which characterizes the European university libraries.  相似文献   

V + H: Hybrid architecture for DSS and OLTP     

María del Pilar Angeles  Victor González Castro 《International Journal of Information Management》2013,33(6):940-947

Previous research has been done to identify the best pragmatic approach that DBMSs must follow to manage different workloads. Some approaches have followed the “One size fits all” approach, trying to incorporate all features in a row-oriented DBMS (also called horizontal) to manage both OLTP and DSS workloads. Additionally, there have been specialized DBMS, following a columnar approach (also called vertical), that focuses on the growing demand to efficiently manage DSS workloads. This paper proposes a combination of both vertical and horizontal DBMS to best manage OLTP and DSS workloads. We have used mature, commercially available products from a single vendor and developed a custom middleware Decision Query Module that identifies the best option for most efficient execution of a query. This V + H architecture also offers the functionality of a mirrored DB without paying twice for storage.  相似文献   

Content management system incorporated in a virtual museum hosting     

Jos Ignacio Rojas-Sola  Miguel Castro-García  María del Pilar Carranza-Caadas 《Journal of Cultural Heritage》2011,12(1):74-81

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SCHOOL INTEGRATION: A PUERTO RICAN VIEW     

Joseph Monserrat 《Equity & Excellence in Education》2013,46(5):7-12

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Sprint mechanical properties in soccer players according to playing standard,position, age and sex     

Thomas A. Haugen  Felix Breitschädel  Stephen Seiler 《Journal of sports sciences》2020,38(9):1070-1076

ABSTRACT

The purpose of this study was to quantify possible differences in sprint mechanical outputs in soccer according to soccer playing standard, position, age and sex. Sprint tests of 674 male and female players were analysed. Theoretical maximal velocity (v₀), horizontal force (F₀), horizontal power (P_max), force-velocity slope (S_FV), ratio of force (RF_max) and index of force application technique (D_RF) were calculated from anthropometric and spatiotemporal data using an inverse dynamic approach applied to the centre-of-mass movement. Players of higher standard exhibited superior F₀, v₀, P_max, RF_max and D_RF scores (small to large effects) than those of lower standard. Forwards displayed clearly superior values for most outputs, ahead of defenders, midfielders and goalkeepers, respectively. Male >28 y players achieved poorer v₀, P_max and RF_max than <20, 20–24 and 24–28 y players (small to moderate), while female <20 y players showed poorer values than 20–24 and >24 y players for the same measures (small). The sex differences in sprint mechanical properties ranged from small to very large. These results provide a holistic picture of the force-velocity-power profile continuum in sprinting soccer players and serve as useful background information for practitioners when diagnosing individual players and prescribing training programmes.  相似文献   

Reseñas     

Pablo del Río  M.a Puy Pérez Echevarría 《Infancia y Aprendizaje》2013,36(33):137-140

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