1,166 research outputs found

    Asteroids and Comets: U.S. and International Law and the Lowest-Probability, Highest Consequence Risk

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    Asteroids and comets pose unique policy problems. They are the ultimate example of a low probability, high consequence event: no one in recorded human history is confirmed to have ever died from an asteroid or a comet, but the odds are that at some time in the next several centuries (and conceivably next year) an asteroid or a comet will cause mass localized destruction and that at some time in the coming half million years (and conceivably next year), an asteroid or a comet will kill several billion people. The sudden extinction of the dinosaurs, and most other species 65 million years ago, is now generally attributed to the impact of a 10-kilometer-wide comet or asteroid at Chicxulub in Mexico\u27s Yucatan Peninsula that left a 110-mile-wide crater. Even our own century has seen smaller-scale impacts. On June 30, 1908, hundreds of square miles of trees were burned and herds of reindeer may have been incinerated in the Tunguska region of Siberia by an explosion with the force of 1,000 Hiroshima bombs, apparently caused by a 60-meter asteroid. Airborne blasts in the kiloton to megaton range were observed in 1930 at the Curuca River in Brazil; in 1947 at Sikhote-Alin, Siberia; in 1965 over Revelstoke, Canada; and over Ontario in 1966 and Alaska in 1969. Most recently, on November 22, 1996, a meteorite crashed into a coffee field in Honduras, leaving a 165-footwide crater

    The triggering of MHD instabilities through photospheric footpoint motions

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    The results of 3D numerical simulations modelling the twisting of a coronal loop due to photospheric vortex motions are presented. The simulations are carried out using an initial purely axial field and an initial equilibrium configuration with twist, . The non-linear and resistive evolutions of the instability are followed. The magnetic field is twisted by the boundary motions into a loop which initially has boundary layers near the photospheric boundaries as has been suggested by previous work. The boundary motions increase the twist in the loop until it becomes unstable. For both cases the boundary twisting triggers the kink instability. In both cases a helical current structure wraps itself around the kinked central current. This current scales linearly with grid resolution indicating current sheet formation. For the cases studied 35-40% of the free magnetic energy is released. This is sufficient to explain the energy released in a compact loop flare

    Intellectual capital and performance in temporary teams

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    Purpose: The purpose of this paper is to deepen resource-based view theory by analyzing how intellectual capital (IC) affects performance in temporary teams and by showing the moderating role of integrative mechanisms. Design/methodology/approach: The research context focuses on 153 national teams of football (NTF), also referred to as national soccer teams, as an example of temporary groups. A partial least squares (PLS) methodology was utilized on a data set built from transfermarkt.com and FIFA world rankings. Three main hypotheses were developed and tested using first a PLS and then an OLS approach. Findings: The results show how IC contributes to performance, extending the findings of previous studies to the context of temporary teams. Additionally, the results show how some integrative mechanisms such as assembly decisions and team leader experience influence temporary team performance by creating an interaction effect with existing IC. Originality/value: This study contributes to IC theories for three reasons. First, it applies IC research to a specific research context: temporary teams, where specific organizational capabilities are required to coordinate resources. Second, the study analyzes the role of integrative mechanisms as moderators of the relationship between IC and performance in temporary teams. Third, the study focuses on NTF as an example of temporary teams

    Developmental Strategies of Proliferating Cryptocurrencies – A Case Study on Solana

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    Cryptocurrencies have disrupted the financial world and created opportunities for businesses to raise capital. However, not all cryptocurrencies have been successful, and identifying the critical factors for success is essential. Many successful cryptocurrencies have established ecosystems and partnerships with leading companies. The purpose of this article is to explore the strategies for building an ecosystem of cryptocurrencies to promote their development and adoption. By examining successful cases and identifying the associated technological innovations and external partnerships, this study aims to provide empirical evidence and insights into the proliferation of cryptocurrencies

    The continental shelf between Cape Town and Cape Agulhas

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    Growth-promoting activity of desmopressin in murine leukemia cells treated in vitro

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    The synthetic vasopressin analogue, desmopressin (dDAVP), has been shown to influence membrane transport of melphalan in murine L5178Y lymphoblasts. Accordingly, the effect of dDAVP on the cytocidal activity of melphalan in L5178Y cells was evaluated. dDAVP did not affect the cytocidal activity of melphalan in these cells, but significantly affected the cloning efficiency of stationary phase or slowly dividing L5178Y cells over a range of concentrations. In particular, stationary phase cells showed an increase in cloning efficiency from 4.3 ± 0.5% in control cells to 7.0 ± 0.3% in cells treated with 25 nM dDAVP (P < 0.001), whereas cells doubling every 26 h showed an increase from 10.8 ± 1.2% in control cells to 21.0 ± 2.0% in cells treated with 150 nM dDAVP (P < 0.001). This phenomenon was associated with significant elevations of 1,2[3H] diacylglycerol after incubation with dDAVP for 9 min (P < 0.01) and total [3H]diacylglycerols after incubation for both 3 min (P < 0.05) and 9 min (P < 0.02). Within 10 s of treatment with 100 nM dDAVP, there was a marked decrease in the levels of inositol 1,4,5-trisphosphate and inositol 1-phosphate, but subsequently no change was observed for up to 9 min after treatment. We postulate that the increase of diacylglycerol content produced by dDAVP might be primarily from a phosphatidylcholine source and that the growth-promoting activity of desmopressin may be a consequence of activation of protein kinase C

    The Role of Celebrities’ Personality Traits & Endorsement on Consumers’ Online Brand Defending and Purchase Behaviour

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    Celebrity endorsements are widely adopted as part of the marketing strategies for many brands, given celebrities can engage their fans to patronize the brand and to distribute celebrity-featuring promotion messages online. With the proliferation of the Internet, these fans may also defend their beloved celebrities when they are being attacked. However, whether a consumer’s positive attitude to the endorser would impact their behaviour toward the endorsed brand remains unclear. Qualitatively studying based on a few leading online communities, we explored the impact of attitude towards brand-endorsing celebrities on online consumers’ behaviour (likelihood of brand defending and purchase intention), which would foster the brand’s electronic word-of-mouth (eWOM). We also identified several endorsers’ traits that drive consumers’ attitudes towards brand-endorsing celebrities and the role of exposure frequency of celebrity-featured advertisements on consumers’ attitudes towards the endorsed brand

    Characterization of the Response of Primary Cells Relevant to Dialysis-Related Amyloidosis to β2-Microglobulin Monomer and Fibrils

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    The formation of insoluble amyloid fibrils is associated with an array of devastating human diseases. Dialysis-related amyloidosis (DRA) is a severe complication of hemodialysis that results in the progressive destruction of the bones and joints. Elevated concentrations of β2-microglobulin (β2m) in the serum of subjects on hemodialysis promote the formation of amyloid fibrils in the osteoarticular tissues, but the cellular basis for the destruction of these tissues in DRA is poorly understood. In this study we performed a systematic analysis of the interaction of monomeric and fibrillar β2m with primary human cells of the types present in the synovial joints of subjects with DRA. Building upon observations that macrophages infiltrate β2m amyloid deposits in vivo we demonstrate that monocytes, the precursors of macrophages, cannot degrade β2m fibrils, and that both monomeric β2m and fibrillar β2m are cytotoxic to these cells. β2m fibrils also impair the formation of bone resorbing osteoclasts from monocytes and reduce the viability of osteoblasts, the cell type that produces bone. As a consequence, we predict that β2m amyloid will disrupt the remodelling of the bone, which is critical for the maintenance of this tissue. Moreover, we show that β2m fibrils reduce the viability of chondrocytes, rationalizing the loss of cartilage in DRA. Together, our observations demonstrate that β2m cytotoxicity has multiple cellular targets in the osteoarticular tissues and is likely to be a key factor in the bone and joint destruction characteristic of DRA

    What’s in a (pseudo)name?: Ethical conundrums for the principles of anonymisation in social media research

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    Scholars from wide-ranging disciplines are turning to social media platforms as research sites, and as platforms expand their communicative possibilities, they create more spaces for users to enact a multitude of identities. Most platforms allow users to have ‘pseudonymous’ identities; that is, they can engage in practices intended to facilitate nonidentifiable content. But pseudonymity presents a series of unique challenges to the principles of anonymisation in qualitative research. This article explores the slippery nature of dealing with pseudonymous social media users’ personally identifiable data during research, framed around my responses to four questions I was asked when I applied for ethical approval to conduct research with pseudonymous fan communities on social media. The four questions concern: (Q1) changing notions of ‘public’ and ‘private’ forms of data; (Q2) identifying underage and therefore vulnerable participants online; (Q3) changes to the processes of obtaining informed consent from social media users; and (Q4) the risks social media research might bring to those conducting it. This article concludes by calling for qualitative researchers and Ethics Review Boards (ERBs) to engage with institutional ethics review across the duration of a project, or at the very least to advocate for ongoing consent as research progresses, especially for (but certainly not limited to) research involving pseudonymous social media users. The article aims to be useful to other researchers facing similar dilemmas. Indeed, given the popularity of pseudonymity on social media and the growing penetration of platforms across global demographics, a need for ethical discussions of this kind is surely set to increase

    Large Scale Proactive Power-Quality Monitoring: An Example from Australia

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    In Australia and many other countries, distribution network service providers (DNSPs) have an obligation to their customers to provide electrical power that is reliable and of high quality. Failure to do so may have significant implications ranging from financial penalties theoretically through to the loss of a license to distribute electricity. In order to ensure the reliability and quality of supply are met, DNSPs engage in monitoring and reporting practice. This paper provides an overview of a large long-running power-quality monitoring project that has involved most of Australia\u27s DNSPs at one time or another. This paper describes the challenges associated with conducting the project as well as some of the important outcomes and lessons learned. A number of novel reporting techniques that have been developed as part of the monitoring project are also presented. A discussion about large-volume data management, and issues related to reporting requirements in future distribution networks is included
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