Of course we share! Testing Assumptions about Social Tagging Systems

Social tagging systems have established themselves as an important part in today's web and have attracted the interest from our research community in a variety of investigations. The overall vision of our community is that simply through interactions with the system, i.e., through tagging and sharing of resources, users would contribute to building useful semantic structures as well as resource indexes using uncontrolled vocabulary not only due to the easy-to-use mechanics. Henceforth, a variety of assumptions about social tagging systems have emerged, yet testing them has been difficult due to the absence of suitable data. In this work we thoroughly investigate three available assumptions - e.g., is a tagging system really social? - by examining live log data gathered from the real-world public social tagging system BibSonomy. Our empirical results indicate that while some of these assumptions hold to a certain extent, other assumptions need to be reflected and viewed in a very critical light. Our observations have implications for the design of future search and other algorithms to better reflect the actual user behavior

Spatiotemporal variation of mammalian protein complex stoichiometries

Table reporting the summary of quantified complex members and their regulation. (XLSX 179 kb

Efficient Bayesian-based Multi-View Deconvolution

Light sheet fluorescence microscopy is able to image large specimen with high resolution by imaging the sam- ples from multiple angles. Multi-view deconvolution can significantly improve the resolution and contrast of the images, but its application has been limited due to the large size of the datasets. Here we present a Bayesian- based derivation of multi-view deconvolution that drastically improves the convergence time and provide a fast implementation utilizing graphics hardware.Comment: 48 pages, 20 figures, 1 table, under review at Nature Method

Nuclear pore component Nup98 is a potential tumor suppressor and regulates posttranscriptional expression of select p53 target genes

The p53 tumor suppressor utilizes multiple mechanisms to selectively regulate its myriad target genes, which in turn mediate diverse cellular processes. Here, using conventional and single-molecule mRNA analyses, we demonstrate that the nucleoporin Nup98 is required for full expression of p21, a key effector of the p53 pathway, but not several other p53 target genes. Nup98 regulates p21 mRNA levels by a posttranscriptional mechanism in which a complex containing Nup98 and the p21 mRNA 3\u27UTR protects p21 mRNA from degradation by the exosome. An in silico approach revealed another p53 target (14-3-3sigma) to be similarly regulated by Nup98. The expression of Nup98 is reduced in murine and human hepatocellular carcinomas (HCCs) and correlates with p21 expression in HCC patients. Our study elucidates a previously unrecognized function of wild-type Nup98 in regulating select p53 target genes that is distinct from the well-characterized oncogenic properties of Nup98 fusion proteins

Internal and external threat in relationship with right-wing attitudes

Objective Previous studies on the relationship between threat and right-wing attitudes have tended to focus on either internal threat, emanating from one's private life, or external threat, originating from society. However, these studies failed to examine whether these types of threats constitute two distinctive dimensions and which of these threats is most closely related to right-wing attitudes. Method In order to explore the dimensions underlying threat, a factor analysis on a variety of threat scales was conducted (Study 1; N?=?300). Furthermore, in a meta-analysis (Study 2; total N?=?22,086) and a questionnaire study in a large representative sample (Study 3, N?=?800) the strength of the relationships of internal and external threat with right-wing attitudes were investigated. Results The present studies revealed that internal and external threat can be considered as two distinct dimensions underlying threat. Moreover, whereas external threat yielded strong relationships with right-wing attitudes, internal threat only explained a minor part of the variance in these attitudes. Conclusions External rather than internal threat underlies the relationship between threat and right-wing attitudes

Validation of the Voluntary Participation in Online Surveys Scale

A comprehensive understanding of participants' motives to complete web-based surveys has the potential to improve dataquality. In this study we tested the construct validity of a scale developed to measure motivation to participate in webbasedsurveys. We expected that 7 different motivations observed in our previous study will form a 3-factor structure, aspredicted by Self-Determination Theory. This web-based questionnaire study comprised 257 participants completing theVoluntary Participation in Online Studies Scale. Their responses to 21 items underwent a principal component analysisand confi rmatory factor analysis. As we expected, three factors were identifi ed: intrinsic motivation, extrinsic motivationand amotivation. In line with Self-Determination Theory there are three distinct groups of motives among web-surveysparticipants with amotivation as an understudied motivational state. We discuss the results suggesting which types ofmotivation might lead to higher quality of data with an emphasis on possible negative effects of amotivation

A new shock tube configuration for studying dust-lifting during the initiation of a coal dust explosion

The traditional defence against propagating coal dust explosions is the application of dry stone dust. This proven and effective safety measure is strictly regulated based on extensive international experience. While new products, such as foamed stone dust, offer significant practical benefits, no benchmark tests currently exist to certify their dust lifting performance in comparison to dry stone dust. This paper reviews the coal dust explosion mechanism, and argues that benchmark testing should focus on dust lifting during the initial development of the explosion, prior to arrival of the flame. In a practical context, this requires the generation of shock waves with Mach numbers ranging from 1.05 to 1.4, and test times of the order of 10’s to 100’s of milliseconds. These proposed test times are significantly longer than previous laboratory studies, however, for certification purposes, it is argued that the dust lifting behaviour should be examined over the full timescales of an actual explosion scenario. These conditions can be accurately targeted using a shock tube at length scales of approximately 50 m. It is further proposed that useful test time can be maximised if an appropriately sized orifice plate is fitted to the tube exit, an arrangement which also offers practical advantages for testing. The paper demonstrates this operating capability with proof-of-concept experiments using The University of Queensland’s X3 impulse facility