3,411 research outputs found
Exploring information literacy in secondary schools in Hong Kong: A case study
Current curriculum reforms in Hong Kong emphasize learning how to learn and project-based learning. The most recent reform introduces "Liberal Studies" as a mandatory school subject in senior secondary school. This article reports on an exploratory case study of the information searching process (ISP) among Form 6 (Grade 12) students in a Liberal Studies course. Researchers examined sources of information used by students, students' cognitive and emotional experience during the ISP, and communication within the collaborative groups. Findings indicated that Internet-based sources were predominant but that most students had difficulty completing the ISP. Work is needed to help students develop a theory of knowledge in which the meaning of information is contextual and the process of interpreting information requires effort. Such work is important if collaborative inquiry projects in Liberal Studies courses are to lead to deep learning. © 2007 Elsevier Inc. All rights reserved.postprin
The Local Stability of Solutions for a Nonlinear Equation
The approach of Kruzkov’s device of doubling the variables is applied to establish the local stability of strong solutions for a nonlinear partial differential equation in the space L1(R) by assuming that the initial value only lies in the space L1(R)∩L∞(R)
On the Study of Global Solutions for a Nonlinear Equation
The well-posedness of global strong solutions for a nonlinear partial differential equation including the Novikov equation is established provided that its initial value v0(x) satisfies a sign condition and v0(x)∈Hs(R) with s>3/2. If the initial value v0(x)∈Hs(R) (1≤s≤3/2) and the mean function of (1-∂x2)v0(x) satisfies the sign condition, it is proved that there exists at least one global weak solution to the equation in the space v(t,x)∈L2([0,+∞),Hs(R)) in the sense of distribution and vx∈L∞([0,+∞)×R)
On the Study of Global Solutions for a Nonlinear Equation
The well-posedness of global strong solutions for a nonlinear partial differential equation including the Novikov equation is established provided that its initial value V 0 ( ) satisfies a sign condition and V 0 ( ) ∈ ( ) with > 3/2. If the initial value V 0 ( ) ∈ ( ) (1 ≤ ≤ 3/2) and the mean function of (1 − 2 )V 0 ( ) satisfies the sign condition, it is proved that there exists at least one global weak solution to the equation in the space V( , ) ∈ 2 ([0, +∞), ( )) in the sense of distribution and V ∈ ∞ ([0, +∞) × )
On the L
A nonlinear generalized Degasperis-Procesi equation is investigated.
Assuming that the strong solution of the equation is bounded in the
sense of L∞R-norm and the initial data belong to the space L1(R)∩L2(R),
we prove that the solutions are stable in the space L1(R)
On the Existence of Global Weak Solutions for a Weakly Dissipative Hyperelastic Rod Wave Equation
Assuming that the initial value v0(x) belongs to the space H1(R), we prove the existence of global weak solutions for a weakly dissipative hyperelastic rod wave equation in the space C([0,∞)×R)⋂L∞([0,∞);H1(R)). The limit of the viscous approximation for the equation is used to establish the existence
Helical Chirality: a Link between Local Interactions and Global Topology in DNA
DNA supercoiling plays a major role in many cellular functions. The global DNA conformation is however intimately linked to local DNA-DNA interactions influencing both the physical properties and the biological functions of the supercoiled molecule. Juxtaposition of DNA double helices in ubiquitous crossover arrangements participates in multiple functions such as recombination, gene regulation and DNA packaging. However, little is currently known about how the structure and stability of direct DNA-DNA interactions influence the topological state of DNA. Here, a crystallographic analysis shows that due to the intrinsic helical chirality of DNA, crossovers of opposite handedness exhibit markedly different geometries. While right-handed crossovers are self-fitted by sequence-specific groove-backbone interaction and bridging Mg2+ sites, left-handed crossovers are juxtaposed by groove-groove interaction. Our previous calculations have shown that the different geometries result in differential stabilisation in solution, in the presence of divalent cations. The present study reveals that the various topological states of the cell are associated with different inter-segmental interactions. While the unstable left-handed crossovers are exclusively formed in negatively supercoiled DNA, stable right-handed crossovers constitute the local signature of an unusual topological state in the cell, such as the positively supercoiled or relaxed DNA. These findings not only provide a simple mechanism for locally sensing the DNA topology but also lead to the prediction that, due to their different tertiary intra-molecular interactions, supercoiled molecules of opposite signs must display markedly different physical properties. Sticky inter-segmental interactions in positively supercoiled or relaxed DNA are expected to greatly slow down the slithering dynamics of DNA. We therefore suggest that the intrinsic helical chirality of DNA may have oriented the early evolutionary choices for DNA topology
Plasminogen Activator Inhibitor-1 4G/5G Gene Polymorphism and Coronary Artery Disease in the Chinese Han Population: A Meta-Analysis
Background: The polymorphism of plasminogen activator inhibitor-1 (PAI-1) 4G/5G gene has been indicated to be correlated with coronary artery disease (CAD) susceptibility, but study results are still debatable. Objective and Methods: The present meta-analysis was performed to investigate the association between PAI-1 4G/5G gene polymorphism and CAD in the Chinese Han population. A total of 879 CAD patients and 628 controls from eight separate studies were involved. The pooled odds ratio (OR) for the distribution of the 4G allele frequency of PAI-1 4G/5G gene and its corresponding 95 % confidence interval (CI) was assessed by the random effect model. Results: The distribution of the 4 G allele frequency was 0.61 for the CAD group and 0.51 for the control group. The association between PAI-1 4G/5G gene polymorphism and CAD in the Chinese Han population was significant under an allelic genetic model (OR = 1.70, 95 % CI = 1.18 to 2.44, P = 0.004). The heterogeneity test was also significant (P,0.0001). Meta-regression was performed to explore the heterogeneity source. Among the confounding factors, the heterogeneity could be explained by the publication year (P = 0.017), study region (P = 0.014), control group sample size (P = 0.011), total sample size (P = 0.011), and ratio of the case to the control group sample size (RR) (P = 0.019). In a stratified analysis by the total sample size, significantly increased risk was only detected in subgroup 2 under an allelic genetic model (OR = 1.93, 95% CI = 1.09 to 3.35, P = 0.02)
Potential conservation of circadian clock proteins in the phylum Nematoda as revealed by bioinformatic searches
Although several circadian rhythms have been described in C. elegans, its molecular clock remains elusive. In this work we employed a novel bioinformatic approach, applying probabilistic methodologies, to search for circadian clock proteins of several of the best studied circadian model organisms of different taxa (Mus musculus, Drosophila melanogaster, Neurospora crassa, Arabidopsis thaliana and Synechoccocus elongatus) in the proteomes of C. elegans and other members of the phylum Nematoda. With this approach we found that the Nematoda contain proteins most related to the core and accessory proteins of the insect and mammalian clocks, which provide new insights into the nematode clock and the evolution of the circadian system.Fil: Romanowski, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; ArgentinaFil: Garavaglia, Matías Javier. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Ing.genética y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goya, María Eugenia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ghiringhelli, Pablo Daniel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Ing.genética y Biolog.molecular y Celular. Area Virus de Insectos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andres. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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