198 research outputs found

    Development and Performance of the PHOT (Portable High-Speed Occultation Telescope) Systems

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    The PHOT (Portable High-Speed Occultation Telescope) systems were developed for the specific purpose of observing stellar occultations by solar system objects. Stellar occultations have unique observing constraints: they may only be observable from certain parts of the globe; they often require a rapid observing cadence; and they require accurate timestamp information for each exposure. The PHOT systems consist of 14" telescopes, CCD cameras, camera mounting plates, GPS-based time standards, and data acquisition computers. The PHOT systems are similar in principle to the POETS systems (Portable Occultation, Eclipse and Transit Systems, described by Souza et al. 2006 and reported on by Gulbis et al. 2008), with the main differences being (a) different CCD/Cameras with slightly different specifications and (b) a stand-alone custom-built time standard used by PHOT, whereas POETS uses a commercial time-standard that is controlled from a computer. Since 2005, PHOT systems have been deployed on over two dozen occasions to sites in the US, Mexico, Chile, Namibia, South Africa, France, Austria, Switzerland, Australia and New Zealand, mounted on portable 14" telescopes or on larger stationary telescopes. Occultation light curves acquired from the 3.9-m AAT (Anglo-Australian Telescope) have produced photometric signal-to-noise ratios (SNR) of 333 per scale height for a stellar occultation by Pluto (Young et al. 2008). In this paper we describe the seven PHOT subsystems in detail (telescopes, cameras, timers and data stations) and present SNR estimates for actual and predicted occultations as functions of star brightness, telescope aperture and frame rate

    International Journal of Human Resource Management (IJHRM) Special Issue on:International human resource management in contexts of high uncertainties

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    The aim of this special issue is to examine more closely of the implementations of international human resource management (IHRM) practices in the contexts of high uncertainties. It seeks contexts of relevance, encompassing those experiencing financial crisis, economic sanctions, political and civil uncertainty, environmental collapse and/or deep recession. It aims to supplement the Danger and Risk as Challenges for HRM in the IJHRM special issue which encompasses terrorism, violent disorder, crime and other physical risks, by focusing on initially seemingly peaceful forms of uncertainty, even if their consequences might lead to societal collapse. While appreciating that these contexts are very different, the key theme that cuts across all of these contexts are the unexpected changes that they brought, creating considerable ambiguity for businesses, and how they manage their people. Businesses will face the challenges of coping in such contexts, with unpredictability in demand, and in supplier relations, in adding greater time pressure to the decision-making process, and in terms of work and employment relations (Pearson & Clair, 1998). Through operating in different settings, multinational enterprises (MNEs) may be able to hedge risk, but at the same time protecting their own interest from a distance can be extremely difficult (Cantwell, Dunning, & Lundan, 2010). They will also impact on MNE decisions to invest and reinvest in particular settings (Oh & Oetzel, 2011). However, reducing or eliminating their presence in the host location is not always possible. MNEs may have substantial resources and infrastructural interests in the host location that need to be protected. Again, there is often a pressing need of MNEs to use expatriates on international assignments to complete strategically critical tasks, but the same time managing expatriate staff becomes much more difficult when countries of domicile become less certain. However, these situations often present golden opportunity for businesses. Studies have found that the option value of MNEs in entering a country under the uncertain conditions can be high (Miller, 1998). This is because government and international bodies often inject considerable amount of investments into the affected countries in aiding the recovery and rebuilding process and, in turn, pumped up the local aggregate demands, opening new opportunities for MNEs in relevant industries (Vigdor, 2008). At the same time, consumers’ demand for products and services may change; demand may not necessarily decline, but what consumers may want may be different, and this will impact on the demands placed on a firm’s human resources. These MNEs may therefore experience expansion of workforce under these situations.Full Tex

    Harnessing collective intelligence for the future of learning – a co-constructed research and development agenda

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    Learning, defined as the process of constructing meaning and developing competencies to act on it, is instrumental in helping individuals, communities, and organizations tackle challenges. When these challenges increase in complexity and require domain knowledge from diverse areas of expertise, it becomes difficult for single individuals to address them. In this context, collective intelligence, a capacity of groups of people to act together and solve problems using their collective knowledge, becomes of great importance. Technologies are instrumental both to support and understand learning and collective intelligence, hence the need for innovations in the area of technologies that can support user needs to learn and tackle collective challenges. Use-inspired research is a fitting paradigm that spans applied solutions and scientific explanations of the processes of learning and collective intelligence, and that can improve the technologies that may support them. Although some conceptual and theoretical work explaining and linking learning with collective intelligence is emerging, technological infrastructures as well as methodologies that employ and evidence that support them are nascent. We convened a group of experts to create a middleground and engage with the priorities for use-inspired research. Here we detail directions and methods they put forward as most promising for advancing a scientific agenda around learning and collective intelligence

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

    Sex differences in oncogenic mutational processes.

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    Sex differences have been observed in multiple facets of cancer epidemiology, treatment and biology, and in most cancers outside the sex organs. Efforts to link these clinical differences to specific molecular features have focused on somatic mutations within the coding regions of the genome. Here we report a pan-cancer analysis of sex differences in whole genomes of 1983 tumours of 28 subtypes as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We both confirm the results of exome studies, and also uncover previously undescribed sex differences. These include sex-biases in coding and non-coding cancer drivers, mutation prevalence and strikingly, in mutational signatures related to underlying mutational processes. These results underline the pervasiveness of molecular sex differences and strengthen the call for increased consideration of sex in molecular cancer research

    Whole-genome landscapes of major melanoma subtypes

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    Melanoma of the skin is a common cancer only in Europeans, whereas it arises in internal body surfaces (mucosal sites) and on the hands and feet (acral sites) in people throughout the world. Here we report analysis of whole-genome sequences from cutaneous, acral and mucosal subtypes of melanoma. The heavily mutated landscape of coding and non-coding mutations in cutaneous melanoma resolved novel signatures of mutagenesis attributable to ultraviolet radiation. However, acral and mucosal melanomas were dominated by structural changes and mutation signatures of unknown aetiology, not previously identified in melanoma. The number of genes affected by recurrent mutations disrupting non-coding sequences was similar to that affected by recurrent mutations to coding sequences. Significantly mutated genes included BRAF, CDKN2A, NRAS and TP53 in cutaneous melanoma, BRAF, NRAS and NF1 in acral melanoma and SF3B1 in mucosal melanoma. Mutations affecting the TERT promoter were the most frequent of all; however, neither they nor ATRX mutations, which correlate with alternative telomere lengthening, were associated with greater telomere length. Most melanomas had potentially actionable mutations, most in components of the mitogen-activated protein kinase and phosphoinositol kinase pathways. The whole-genome mutation landscape of melanoma reveals diverse carcinogenic processes across its subtypes, some unrelated to sun exposure, and extends potential involvement of the non-coding genome in its pathogenesis
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