130 research outputs found
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The Cosmos Project: a journey to the stars
There seems to be some agreement that âscience for allâ does not necessarily mean âone size fits allâ (Lynch, 2001). Teaching scientific disciplines in schools has been traditionally concerned with delivering science as a product with a main focus on its conceptual structure. In our research we propose to concentrate on science as a process, putting it in the societal context. We introduce the Cosmos project that aims to explore the use of narrative and performative languages, as well as new media technologies in relation to delivering complex scientific topics to pre-school children aged three to six. We created a theatrical piece and developed a set of new interactive preschool activities that enabled young learners to participate and contribute to their learning through physical engagement enhanced by modern technologies. This paper presents a critical discussion about the recent tendencies in teaching science to young learners; the rationale for the Cosmos project and its main research objectives. It will conclude with evaluation of the pre- and postperformance educational activities
Universal factorized formula for the cross-section of two-particle scattering
We analyze the process of two-particle scattering with unstable particle in
an intermediate state. It was shown that the cross-section can be represented
in the universal factorized form for an arbitrary set of particles.
Phenomenological analysis of factorization effect is fulfilled.Comment: 8 pages, corrected typos. change conten
Factorization effects in a model of unstable particles
The effects of factorization are considered within the framework of the model
of unstable particles with a smeared mass. It is shown that two-particle cross
section and three-particle decay width can be described by the universal
factorized formulae for an unstable particles of an arbitrary spin in an
intermediate state. The exact factorization is caused by the specific structure
of the model unstable-particle propagators. This result is generalized to
complicated scattering and decay-chain processes with unstable particles in
intermediate states. We analyze applicability of the method and evaluate its
accuracy.Comment: 13 pages, 7 figure
Efficient motif finding algorithms for large-alphabet inputs
<p>Abstract</p> <p>Background</p> <p>We consider the problem of identifying motifs, recurring or conserved patterns, in the biological sequence data sets. To solve this task, we present a new deterministic algorithm for finding patterns that are embedded as exact or inexact instances in all or most of the input strings.</p> <p>Results</p> <p>The proposed algorithm (1) improves search efficiency compared to existing algorithms, and (2) scales well with the size of alphabet. On a synthetic planted DNA motif finding problem our algorithm is over 10Ă more efficient than MITRA, PMSPrune, and RISOTTO for long motifs. Improvements are orders of magnitude higher in the same setting with large alphabets. On benchmark TF-binding site problems (FNP, CRP, LexA) we observed reduction in running time of over 12Ă, with high detection accuracy. The algorithm was also successful in rapidly identifying protein motifs in Lipocalin, Zinc metallopeptidase, and supersecondary structure motifs for Cadherin and Immunoglobin families.</p> <p>Conclusions</p> <p>Our algorithm reduces computational complexity of the current motif finding algorithms and demonstrate strong running time improvements over existing exact algorithms, especially in important and difficult cases of large-alphabet sequences.</p
Near-threshold boson pair production in the model of smeared-mass unstable particles
Near-threshold production of boson pairs is considered within the framework
of the model of unstable particles with smeared mass. We describe the principal
aspects of the model and consider the strategy of calculations including the
radiative corrections. The results of calculations are in good agreement with
LEP II data and Monte-Carlo simulations. Suggested approach significantly
simplifies calculations with respect to the standard perturbative one.Comment: 15 pages, 6 figures, minor corrections, references adde
Factorization in the model of unstable particles with continuous masses
We study processes with unstable particles in intermediate time-like states.
It is shown that the amplitudes squared of such processes factor exactly in the
framework of the model of unstable particles with continuous masses. Decay
widths and cross sections can then be represented in a universal factorized
form for an arbitrary set of interacting particles. This exact factorization is
caused by specific structure of propagators in the model. We formulate the
factorization method and perform a phenomenological analysis of the
factorization effects. The factorization method considerably simplifies
calculations while leading to compact and reasonable results.Comment: 20 pages, 6 figure
Chemical Modifications Mark Alternatively Spliced and Uncapped Messenger RNAs in Arabidposis
Posttranscriptional chemical modification of RNA bases is a widespread and physiologically relevant regulator of RNA maturation, stability, and function. While modifications are best characterized in short, noncoding RNAs such as tRNAs, growing evidence indicates that mRNAs and long noncoding RNAs (lncRNAs) are likewise modified. Here, we apply our high-throughput annotation of modified ribonucleotides (HAMR) pipeline to identify and classify modifications that affect Watson-Crick base pairing at three different levels of the Arabidopsis thaliana transcriptome (polyadenylated, small, and degrading RNAs). We find this type of modifications primarily within uncapped, degrading mRNAs and lncRNAs, suggesting they are the cause or consequence of RNA turnover. Additionally, modifications within stable mRNAs tend to occur in alternatively spliced introns, suggesting they regulate splicing. Furthermore, these modifications target mRNAs with coherent functions, including stress responses. Thus, our comprehensive analysis across multiple RNA classes yields insights into the functions of covalent RNA modifications in plant transcriptomes
DASHR: Database of Small Human Noncoding RNAs
Small non-coding RNAs (sncRNAs) are highly abundant RNAs, typically long, that act as key regulators of diverse cellular processes. Although thousands of sncRNA genes are known to exist in the human genome, no single database provides searchable, unified annotation, and expression information for full sncRNA transcripts and mature RNA products derived from these larger RNAs. Here, we present the Database of small human noncoding RNAs (DASHR)
. DASHR contains the most comprehensive information to date on human sncRNA genes and mature sncRNA products. DASHR provides a simple user interface for researchers to view sequence and secondary structure, compare expression levels, and evidence of specific processing across all sncRNA genes and mature sncRNA products in various human tissues. DASHR annotation and expression data covers all major classes of sncRNAs including microRNAs (miRNAs), Piwi-interacting (piRNAs), small nuclear, nucleolar, cytoplasmic (sn-, sno-, scRNAs, respectively), transfer (tRNAs), and ribosomal RNAs (rRNAs). Currently, DASHR (v1.0) integrates 187 smRNA high-throughput sequencing (smRNA-seq) datasets with over 2.5 billion reads and annotation data from multiple public sources. DASHR contains annotations for ~48,000 human sncRNA genes and mature sncRNA products, 82% of which are expressed in one of more of the curated tissues. DASHR is available at http://lisanwanglab.org/DASHR
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