2,400 research outputs found

    Effects of Aesthetics and Playfulness on Web Usability – An empirical investigation

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    Limited empirical research exists on the explicit relevance of hedonic dimensions (aesthetics and playfulness) of humancomputer interaction design to usability. This research aims to determine the effects of color temperature on the perceptions of websites aesthetics, playfulness, and in turn usability. A Partial Least Squares (PLS) analysis of data collected from 328 participants in a four-group between-subject research design involving the use of a mock hotel website offered support for all nine hypotheses proposed. ‘Cooler’ colors (e.g. blue) were found to favorably impact perceptions of classical aesthetics, which in turn influenced perceptions of efficiency positively, while also correlating with perceptions of expressive aesthetics. The latter, on the other hand, were affected favorably by warmer colors (e.g. red), and had a positive effect on perceptions of playfulness. In line with prior usability studies, positive relationships between efficiency and effectiveness respectively and satisfaction with the Website were supported, and by considering the shown positive relationship between playfulness and satisfaction 60% of the variance in satisfaction was explained. Implications for theory and practice are also discussed

    Developmental plasticity, cell fate specification and morphogenesis in the early mouse embryo

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    A critical point in mammalian development is when the early embryo implants into its mother's uterus. This event has historically been difficult to study due to the fact that it occurs within the maternal tissue and therefore is hidden from view. In this review, we discuss how the mouse embryo is prepared for implantation and the molecular mechanisms involved in directing and coordinating this crucial event. Prior to implantation, the cells of the embryo are specified as precursors of future embryonic and extra-embryonic lineages. These preimplantation cell fate decisions rely on a combination of factors including cell polarity, position and cell–cell signalling and are influenced by the heterogeneity between early embryo cells. At the point of implantation, signalling events between the embryo and mother, and between the embryonic and extraembryonic compartments of the embryo itself, orchestrate a total reorganization of the embryo, coupled with a burst of cell proliferation. New developments in embryo culture and imaging techniques have recently revealed the growth and morphogenesis of the embryo at the time of implantation, leading to a new model for the blastocyst to egg cylinder transition. In this model, pluripotent cells that will give rise to the fetus self-organize into a polarized three-dimensional rosette-like structure that initiates egg cylinder formation

    Transcriptome Sequencing Demonstrates that Human Papillomavirus Is Not Active in Cutaneous Squamous Cell Carcinoma

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    β-Human papillomavirus (β-HPV) DNA is present in some cutaneous squamous cell carcinomas (cuSCCs), but no mechanism of carcinogenesis has been determined. We used ultra-high-throughput sequencing of the cancer transcriptome to assess whether papillomavirus transcripts are present in these cancers. In all, 67 cuSCC samples were assayed for β-HPV DNA by PCR, and viral loads were measured with type-specific quantitative PCR. A total of 31 SCCs were selected for whole transcriptome sequencing. Transcriptome libraries were prepared in parallel from the HPV18-positive HeLa cervical cancer cell line and HPV16-positive primary cervical and periungual SCCs. Of the tumors, 30% (20/67) were positive for β-HPV DNA, but there was no difference in β-HPV viral load between tumor and normal tissue (P=0.310). Immunosuppression and age were significantly associated with higher viral load (P=0.016 for immunosuppression; P=0.0004 for age). Transcriptome sequencing failed to identify papillomavirus expression in any of the skin tumors. In contrast, HPV16 and HPV18 mRNA transcripts were readily identified in primary cervical and periungual cancers and HeLa cells. These data demonstrate that papillomavirus mRNA expression is not a factor in the maintenance of cuSCCs

    No Association of Obesity and Type 2 Diabetes Mellitus Related Genetic Variants With Colon Cancer

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    Background: Obesity and type 2 diabetes mellitus (T2D) are known risk factors for colon cancer. Recent reports from a number of genome wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) associated with obesity and T2D. Here we tested the hypothesis that these SNPs may also be associated with risk of colon cancer. Methods: We genotyped nine SNPs reported in GWAS of obesity and/or T2D, including SNPs in HHEX, KCNJ11, SLC30A8, FTO, CDKN2, CDKAL1, TCF2, and the rs9300039 SNP in an intergenic region, in 561 colon cancer cases and 721 population controls. Results: None of these SNPs were statistically significantly associated with colon cancer in our sample. Conclusions: Overall, these results suggest that these obesity and T2D genetic susceptibility loci are unlikely to influence the risk of colon cancer

    LoCuSS: The Near-Infrared Luminosity and Weak-Lensing Mass Scaling Relation of Galaxy Clusters

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    We present the first scaling relation between weak-lensing galaxy cluster mass, MWLM_{WL}, and near-infrared luminosity, LKL_K. Our results are based on 17 clusters observed with wide-field instruments on Subaru, the United Kingdom Infrared Telescope, the Mayall Telescope, and the MMT. We concentrate on the relation between projected 2D weak-lensing mass and spectroscopically confirmed luminosity within 1Mpc, modelled as MWLLKbM_{WL} \propto L_{K}^b, obtaining a power law slope of b=0.830.24+0.27b=0.83^{+0.27}_{-0.24} and an intrinsic scatter of σlnMWLLK=105+8%\sigma_{lnM_{WL}|L_{K}}=10^{+8}_{-5}\%. Intrinsic scatter of ~10% is a consistent feature of our results regardless of how we modify our approach to measuring the relationship between mass and light. For example, deprojecting the mass and measuring both quantities within r500r_{500}, that is itself obtained from the lensing analysis, yields σlnMWLLK=105+7%\sigma_{lnM_{WL}|L_{K}}=10^{+7}_{-5}\% and b=0.970.17+0.17b=0.97^{+0.17}_{-0.17}. We also find that selecting members based on their (J-K) colours instead of spectroscopic redshifts neither increases the scatter nor modifies the slope. Overall our results indicate that near-infrared luminosity measured on scales comparable with r500r_{500} (typically 1Mpc for our sample) is a low scatter and relatively inexpensive proxy for weak-lensing mass. Near-infrared luminosity may therefore be a useful mass proxy for cluster cosmology experiments.Comment: 9 Pages, 5 Figures, 3 Tables. Submitted to MNRA

    Orbits for the Impatient: A Bayesian Rejection Sampling Method for Quickly Fitting the Orbits of Long-Period Exoplanets

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    We describe a Bayesian rejection sampling algorithm designed to efficiently compute posterior distributions of orbital elements for data covering short fractions of long-period exoplanet orbits. Our implementation of this method, Orbits for the Impatient (OFTI), converges up to several orders of magnitude faster than two implementations of MCMC in this regime. We illustrate the efficiency of our approach by showing that OFTI calculates accurate posteriors for all existing astrometry of the exoplanet 51 Eri b up to 100 times faster than a Metropolis-Hastings MCMC. We demonstrate the accuracy of OFTI by comparing our results for several orbiting systems with those of various MCMC implementations, finding the output posteriors to be identical within shot noise. We also describe how our algorithm was used to successfully predict the location of 51 Eri b six months in the future based on less than three months of astrometry. Finally, we apply OFTI to ten long-period exoplanets and brown dwarfs, all but one of which have been monitored over less than 3% of their orbits, producing fits to their orbits from astrometric records in the literature.Comment: 32 pages, 28 figures, Accepted to A

    Associations of passerine birds, rabbits, and ticks with \u3cem\u3eBorrelia miyamotoi and Borrelia andersonii\u3c/em\u3e in Michigan, U.S.A.

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    Background Wild birds contribute to maintenance and dissemination of vectors and microbes, including those that impact human, domestic animal, and wildlife health. Here we elucidate roles of wild passerine birds, eastern cottontail rabbits (Sylvilagus floridanus), and Ixodes dentatus ticks in enzootic cycles of two spirochetes, Borrelia miyamotoi and B. andersonii in a region of Michigan where the zoonotic pathogen B. burgdorferi co-circulates. Methods Over a four-year period, wild birds (n = 19,631) and rabbits (n = 20) were inspected for tick presence and ear tissue was obtained from rabbits. Samples were tested for Borrelia spirochetes using nested PCR of the 16S-23S rRNA intergenic spacer region (IGS) and bidirectional DNA sequencing. Natural xenodiagnosis was used to implicate wildlife reservoirs. Results Ixodes dentatus, a tick that specializes on birds and rabbits and rarely bites humans, was the most common tick found, comprising 86.5% of the 12,432 ticks collected in the study. The relapsing fever group spirochete B. miyamotoi was documented for the first time in ticks removed from wild birds (0.7% minimum infection prevalence; MIP, in I. dentatus), and included two IGS strains. The majority of B. miyamotoi-positive ticks were removed from Northern Cardinals (Cardinalis cardinalis). Borrelia andersonii infected ticks removed from birds (1.6% MIP), ticks removed from rabbits (5.3% MIP), and rabbit ear biopsies (5%) comprised twelve novel IGS strains. Six species of wild birds were implicated as reservoirs for B. andersonii. Frequency of I. dentatus larval and nymphal co-feeding on birds was ten times greater than expected by chance. The relatively well-studied ecology of I. scapularis and the Lyme disease pathogen provides a context for understanding how the phenology of bird ticks may impact B. miyamotoi and B. andersonii prevalence and host associations. Conclusions Given the current invasion of I. scapularis, a human biting species that serves as a bridge vector for Borrelia spirochetes, human exposure to B. miyamotoi and B. andersonii in this region may increase. The presence of these spirochetes underscores the ecological complexity within which Borrelia organisms are maintained and the need for diagnostic tests to differentiate among these organisms
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