1,359 research outputs found
Number sense : the underpinning understanding for early quantitative literacy
No full textThe fundamental meaning of Quantitative Literacy (QL) as the application of quantitative knowledge or reasoning in new/unfamiliar contexts is problematic because how we acquire knowledge, and transfer it to new situations, is not straightforward. This article argues that in the early development of QL, there is a specific corpus of numerical knowledge which learners need to integrate into their thinking, and to which teachers should attend. The paper is a rebuttal to historically prevalent (and simplistic) views that the terrain of early numerical understanding is little more than simple counting devoid of cognitive complexity. Rather, the knowledge upon which early QL develops comprises interdependent dimensions: Number Knowledge, Counting Skills and Principles, Nonverbal Calculation, Number Combinations and Story Problems - summarised as Number Sense. In order to derive the findings for this manuscript, a realist synthesis of recent Education and Psychology literature was conducted. The findings are of use not only when teaching very young children, but also when teaching learners who are experiencing learning difficulties through the absence of prerequisite numerical knowledge. As well distilling fundamental quantitative knowledge for teachers to integrate into practice, the review emphasises that improved pedagogy is less a function of literal applications of reported interventions, on the grounds of perceived efficacy elsewhere, but based in refinements of teachers' understandings. Because teachers need to adapt instructional sequences to the actual thinking and learning of learners in their charge, they need knowledge that allows them to develop their own theoretical understanding rather than didactic exhortations
PiCO QL: A software library for runtime interactive queries on program data
No full textAbstractPico ql is an open source c/c++ software whose scientific scope is real-time interactive analysis of in-memory data through sql queries. It exposes a relational view of a system’s or application’s data structures, which is queryable through sql. While the application or system is executing, users can input queries through a web-based interface or issue web service requests. Queries execute on the live data structures through the respective relational views. pico ql makes a good candidate for ad-hoc data analysis in applications and for diagnostics in systems settings. Applications of pico ql include the Linux kernel, the Valgrind instrumentation framework, a gis application, a virtual real-time observatory of stellar objects, and a source code analyser
Crowd Counting via Attention and Multi-Feature Fused Network
No full textWith the rapid development of Internet of Everything and artificial intelligence techniques and massive amounts of video surveillance data, crowd counting has drawn extensive attention in computer vision. Inspired by deep learning methods, convolutional neural networks (CNN) have been dedicated to improving the effectiveness of crowd counting. As CNN is unable to capture the continuous size changes of heads in images, the large-scale variations impede the development of crowd counting. To solve this problem, this paper presents an attention and multi-feature fused network (AMFNet) containing a multi-level feature extractor and four attentional density estimator (ADE) modules. The multi-level extractor is used to extract the features of different sizes and various kinds of context information based on a deep network backbone. The existing ADE modules are built to merge different level features to generate a high-quality density map. A channel attention unit is adopted in the ADE modules to identify the head accurately. Then, four ADE modules are applied to exploit multi-level features and generate a fine-grained density map for coping with various scales. The experiment results show that the proposed AMFNet performs well in dense crowd scenarios, and that it is comparable to mainstream methods in terms of accuracy and robustness
Fabbisogni energetici per edifici caratterizzanti il terziario in Italia: aspetti termici ed illuminotecnici
No full textIl presente lavoro verte sull'individuazione di benchmark di fabbisogno energetico per edifici di riferimento con destinazione d'uso non-residenziale. In particolare, si intende fornire profili tipo di domanda energetica per l'illuminazione artificiale, al fine di valutarne l'effetto sui profili di fabbisogno di energia per la climatizzazione estiva ed invernale, nonché di individuare le variabili che maggiormente incidono sulla loro determinazione. Per giungere a questi risultati, ci si avvale dell'uso di programmi informatici di simulazione dinamica riconosciuti ed impiegati a livello scientifico, in ambito europeo ed extraeuropeo (Energy Plus). La ricerca viene condotta sotto vari aspetti: architettonico, energetico e ambientale. Il primo obiettivo, partendo dalle indicazioni bibliografiche, legislative e normative, è quello di caratterizzare in modo univoco gli edifici di riferimento per le varie destinazioni d'uso oggetto di analisi: edifici per l'istruzione, ed edifici terziari. Gli edifici di riferimento intendono costituire archetipi rappresentativi del patrimonio edilizio italiano. Il secondo obiettivo è di tipo energetico: si intende definire profili tipo di domanda energetica per l'illuminazione artificiale degli ambienti. Si intendono inoltre valutare contestualmente i fabbisogni energetici netti per il riscaldamento e il raffrescamento degli ambienti. L'obiettivo finale è riuscire a determinare le migliori soluzioni progettuali per la minimizzazione del fabbisogno di energia connesso all'illuminazione, in relazione alle destinazioni d'uso dei differenti edifici, nonché le variabili che più incidono per indirizzare al meglio le attenzioni progettuali in caso di nuova realizzazione. Il presente lavoro, dopo un primo inquadramento generale in cui si delinea quello che è lo stato dell'arte della valutazione dei fabbisogni energetici e della ricerca scientifica in materia di illuminazione artificiale di ambienti non residenziali, passa poi ad indagare il significato di archetipo e a definire degli archetipi edilizi per il patrimonio immobiliare costruito a destinazione d'uso scolastica e terziaria. Successivamente vengono descritti i modelli di calcolo impiegati e sono dettagliati i dati di input impiegati per la loro definizione. Sono infine esplicati i risultati ottenuti, con individuazione dei valori di benchmark energetico per gli archetipi edilizi scolastici e terziari, e con l'analisi di quelle che sono le grandezze maggiormente influenti sul fabbisogno energetico per illuminazion
Determining the number of factors in a multivariate error correction--volatility factor model
No full textIn order to describe the co-movements in both conditional mean and conditional variance of high dimensional non-stationary time series by dimension reduction, we introduce the conditional heteroscedasticity with factor structure to the error correction model (ECM). The new model is called the error correction--volatility factor model (EC--VF). Some specification and estimation approaches are developed. In particular, the determination of the number of factors is discussed. Our setting is general in the sense that we impose neither i.i.d. assumption on idiosyncratic components in the factor structure nor independence between factors and idiosyncratic errors. We illustrate the proposed approach with a Monte Carlo simulation and a real data example. Copyright The Author(s). Journal compilation Royal Economic Society 2008
Three angiotensin-converting enzyme inhibitors from Rabdosia coetsa
No full textThe EtOAc extract of Rabdosia coetsa showed angiotensin-converting enzyme (ACE) inhibitory activity. Bioassay-guided isolation of this extract yielded ethyl caffeate (1), rosmarinic acid (2) and methyl rosmarinate (3), which inhibited ACE activity by 32.42%, 55.19% and 39.50% respectively, at the concentration of 10 mu g/ml. (c) 2007 Elsevier GmbH. All rights reserved
Three-dimensional finite element analysis of unilateral and bilateral pedicle screw fixation with intervertebral body fusion for degenerative lumbar instability
No full textThis study aims to establish three-dimensional finite element models of lumbar instability, and compares the biomechanics of unilateral and bilateral pedicle screw fixation with intervertebral body fusion. Simulated physiological loads with axial compression, anterior flexion, posterior extension, left lateral bending, right lateral bending, left-handed rotation, and right-handed rotation were applied in unilateral and bilateral fixation models. The stresses of pedicle screws, intervertebral fusion cages, and adjacent intervertebral discs, and the displacement of the vertebral body in two models were recorded and compared. Under 7 kinds of loads, the stresses of screws in a unilateral fixation model were higher than in a bilateral fixation model, but there were no significant differences (P>0.05). Under loads with left and right lateral bending, and left-and right-handed rotation, the stresses of intervertebral fusion cages in a unilateral fixation model were significantly higher than in a bilateral fixation model (P<0.05). Under 6 kinds of loads except for axial compression, the stresses of adjacent upper and lower intervertebral discs in a bilateral fixation model were clearly greater than in a unilateral fixed model (P<0.05), and the stress of upper intervertebral discs was clearly greater than that of lower intervertebral discs (P<0.05). There was no significant difference in L4 vertebral body displacement between the two models under different loads (P>0.05). Unilateral pedicle screw fixation with intervertebral body fusion can be used for treatment of lumbar instability. It can provide initial stability for spinal fusion, and reduce the effect on adjacent segment degeneration.</span
Four-color DNA sequencing by synthesis on a chip using photocleavable fluorescent nucleotides
No full textWe report four-color DNA sequencing by synthesis (SBS) on a chip, using four photocleavable fluorescent nucleotide analogues (dGTP-PC-Bodipy-FL-510, dUTP-PC-R6G, dATP-PC-ROX, and dCTP-PC-Bodipy-650) (PC, photocleavable; Bodipy, 4,4-difluoro-4-bora3a,4a-diaza-s-indacene; ROX, 6-carboxy-X-rhodamine; R6G, 6-carboxyrhodamine-6G). Each nucleotide analogue consists of a different fluorophore attached to the 5 position of the pyrimidines and the 7 position of the purines through a photocleavable 2-nitrobenzyl linker. After verifying that these nucleotides could be successfully incorporated into a growing DNA strand in a solution-phase polymerase reaction and the fluorophore could be cleaved using laser irradiation (approximate to 355 nm) in 10 sec, we then performed an SBS reaction on a chip that contains a self-priming DNA template covalently immobilized by using 1,3-dipolar azide-alkyne cycloaddition. The DNA template was produced by PCR, using an azido-labeled primer, and the self-priming moiety was attached to the immobilized DNA template by enzymatic ligation. Each cycle of SBS consists of the incorporation of the photocleavable fluorescent nucleotide into the DNA, detection of the fluorescent signal, and photocleavage of the fluorophore. The entire process was repeated to identify 12 continuous bases in the DNA template. These results demonstrate that photocleavable fluorescent nucleotide analogues can be incorporated accurately into a growing DNA strand during a polymerase reaction in solution and on a chip. Moreover, all four fluorophores can be detected and then efficiently cleaved using near-UV irradiation, thereby allowing continuous identification of the DNA template sequence. Optimization of the steps involved in this SBS approach will further increase the read-length.National Insititutes of Health Center of Excellence in Genomic Science Grants P50 HG002806 and R01 HG003582 and the Packard Fellowship for Science and Engineerin
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