5,183 research outputs found

    Revisiting the holographic dark energy in a non-flat universe: alternative model and cosmological parameter constraints

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    We propose an alternative model for the holographic dark energy in a non-flat universe. This new model differs from the previous one in that the IR length cutoff LL is taken to be exactly the event horizon size in a non-flat universe, which is more natural and theoretically/conceptually concordant with the model of holographic dark energy in a flat universe. We constrain the model using the recent observational data including the type Ia supernova data from SNLS3, the baryon acoustic oscillation data from 6dF, SDSS-DR7, BOSS-DR11, and WiggleZ, the cosmic microwave background data from Planck, and the Hubble constant measurement from HST. In particular, since some previous studies have shown that the color-luminosity parameter β\beta of supernovae is likely to vary during the cosmic evolution, we also consider such a case that β\beta in SNLS3 is time-varying in our data fitting. Compared to the constant β\beta case, the time-varying β\beta case reduces the value of χ2\chi^2 by about 35 and results in that β\beta deviates from a constant at about 5σ\sigma level, well consistent with the previous studies. For the parameter cc of the holographic dark energy, the constant β\beta fit gives c=0.65±0.05c=0.65\pm 0.05 and the time-varying β\beta fit yields c=0.72±0.06c=0.72\pm 0.06. In addition, an open universe is favored (at about 2σ\sigma) for the model by the current data.Comment: 8 pages, 4 figure

    The impact of marital conflict on adolescent adjustment

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    The present study examines the impact of marital conflict on adolescent adjustment problems. Based on this general interest, the study further explores several related research questions, such as what specific aspects of marital conflict lead to adolescent adjustment problems, whether changes in marital conflict predict changes in adolescent problems, what kinds of adolescent problems are exhibited, and by what processes the relation between marital conflict and adolescent adjustment problems operates. While focusing on these research issues, this study also tries to overcome some of the methodological limitations in previous studies. The study used data from the Iowa Youth and Families Project. The results from structural equation modeling and latent growth curve analyses demonstrated that (1) two specific aspects of marital conflict, overt marital conflict and conflict over child-rearing, as well as general marital distress, had negative influences on adolescent adjustment; (2) increases in general marital distress and overt marital conflict predicted increases in adolescent problems over time; (3) poor parenting behavior mediated the relation between marital problems and adolescent poor well-being, externalizing problems, and internalizing problems, whereas adolescent feelings of insecurity mediated the relation between marital problems and adolescent poor emotional well-being and internalizing problems; (4) no moderating effect by poor parenting behavior or adolescent feelings of insecurity was found; and (5) the findings did not differ by adolescent gender

    SNP analysis reveals an evolutionary acceleration of the human-specific microRNAs

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    MicroRNAs are one class of important gene regulators at the post-transcriptional level by binding to the 3’UTRs of target mRNAs. It has been reported that human microRNAs are evolutionary conserved and show lower single nucleotide polymorphisms (SNPs) than their flanking regions. However, in this study, we report that the human-specific microRNAs show a higher SNP density than both the conserved microRNAs and other control regions, suggesting rapid evolution and positive selection has occurred in these regions. Furthermore, we observe that the human-specific microRNAs show greater SNPs minor allele frequency and the SNPs in the human-specific microRNAs show fewer effects on the stability of the microRNA secondary structure, indicating that the SNPs in the human-specific microRNAs tend to be less deleterious. Finally, two microRNAs hsa-mir-423 (SNP: rs6505162), hsa-mir-608 (SNP: rs4919510) and 288 target genes that have apparently been under recent positive selection are identified. These findings will improve our understanding of the functions, evolution, and population disease susceptibility of human microRNAs

    A Colour Design Tool Based on Empirical Studies

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    A colour design tool targeted at both unskilled consumers and professional designers is currently under development, on the basis of psychophysical studies into semantic associations of colour, the cultural influences and colour harmony. From experimental results for single-colour associations, 3 underlying factors were identified: “warm-cool”, “heavy-light” and “active-passive”, which were found to agree well with those identified by earlier research. For colour-combination associations, an “additive property” of colour association was discovered: the semantic score of a colour combination can be determined by averaging semantic scores of each constituent colour in that combination. According to the experimental results, there were 4 general patterns of colour harmony: similarity in hue and chroma, difference in lightness, high lightness and the hue effects. While the proposed colour design tool is still in its development stage and has a number of shortcomings, the system is believed to provide practical assistance and support not only for unskilled users but also for designers. Keywords: colour design; colour harmony; colour association; cross-cultural study; e-shopping; colour decision-making; design process; psychophysical method</p
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