5,182 research outputs found

    Developing a Holistic Fire Risk Assessment Framework for Building Construction Sites in Hong Kong

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    Amongst all types of construction accidents, industrial practitioners tend to pay less attention to the prevention of fires at construction sites.  Although fires may not occur frequently on construction sites, statistics show that when they do, the consequences are very serious; involving fatalities, injuries, serious project delays and financial loss.  There are many reasons why fires occur on sites, but a simple lack of awareness of the risks of fire is a major contributor.  Fire risk assessment is not commonly performed on sites.  Hence, it is believed that an appropriate assessment method for evaluating potential fire risk is required in order to improve the awareness of fire risk on construction sites.  This paper reports on the key findings of a research project which aims to develop a comprehensive, objective, reliable, and practical fire risk assessment framework for building construction sites based in Hong Kong.  A comprehensive list of those factors (or conditions) which may constitute a fire risk was compiled using desktop research and structured face-to-face interviews with experienced site personnel.  This list of factors was then used to develop a questionnaire survey form and the Reliability Interval Method (RIM) was used to analyse the survey results and determine the relative importance and rankings of the various fire risk factors at a broad level and risk sub-factors at a detailed level.  It was found that the fire risk factor of “Fire Services Equipment and Installations” has the greatest impact on construction site fire safety, with “Means of Escape in Case of Fire” being the second, and “Attitude of Main Contractor towards Fire Safety” being the third.  In fact, it is the main contractor who plays the pivotal role in maintaining construction site fire safety, which is in line with the high ranking given to the fire risk factor of “Attitude of Main Contractor towards Fire Safety”.  The proposed fire risk assessment framework can be used to develop a useful checklist for assessing the overall level of fire risk for a construction site, and to identify any areas needing improvement.  Although the fire risk assessment framework was developed locally in Hong Kong, the research methodology could be replicated in other countries to produce similar frameworks for international comparison.  Such an extension would aid the understanding of the management of fire risk on construction sites and help discover differences between countries

    Enabling multiplexed testing of pooled donor cells through whole-genome sequencing

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    We describe a method that enables the multiplex screening of a pool of many different donor cell lines. Our method accurately predicts each donor proportion from the pool without requiring the use of unique DNA barcodes as markers of donor identity. Instead, we take advantage of common single nucleotide polymorphisms, whole-genome sequencing, and an algorithm to calculate the proportions from the sequencing data. By testing using simulated and real data, we showed that our method robustly predicts the individual proportions from a mixed-pool of numerous donors, thus enabling the multiplexed testing of diverse donor cells en masse.National Human Genome Research Institute (U.S.) (Grant RM1HG008525)Robert Wood Johnson Foundation (Grant 74178

    A Free-Form Prediction for the Reappearance of Supernova Refsdal in the Hubble Frontier Fields Cluster MACSJ1149.5+2223

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    The massive cluster MACSJ1149.5+2223(z=0.544) displays five very large lensed images of a well resolved spiral galaxy at zspect=1.491z_{\rm spect}=1.491. It is within one of these images that the first example of a multiply-lensed supernova has been detected recently as part of the Grism Lens-Amplified Survey from Space. The depth of this data also reveals many HII regions within the lensed spiral galaxy which we identify between the five counter-images. Here we expand the capability of our free-form method to incorporate these HII regions locally, with other reliable lensed galaxies added for a global solution. This improved accuracy allows us to estimate when the Refsdal supernova will appear within the other lensed images of the spiral galaxy to an accuracy of ∌\sim 7\%. We predict this supernova will reappear in one of the counter-images (RA=11:49:36.025, DEC=+22:23:48.11, J2000) and on November 1st^{st} 2015 (with an estimated error of ±\pm 25 days) it will be at the same phase as it was when it was originally discovered, offering a unique opportunity to study the early phases of this supernova and to examine the consistency of the mass model and the cosmological model that have an impact on the time delay prediction.Comment: 12 images, 11 pages. Mateches accepted version in MNRAS. MNRAS in pres

    SystÚmes de soutien des réseaux sociaux scientifiques : Une exploration qualitative des catalyseurs et des obstacles aux nouvelles études en médecine universitaire

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    Introduction: As academia begins to incorporate modern communication technologies into its scholarly structures, there are both enablers and barriers which foster academics’ uptake of these innovations. Those who are early adopters of academic social media - whether it be for education, research-related networking, or knowledge translation - may therefore be best positioned to highlight both enablers and barriers within their work environments. Methods: The authors conducted a constructivist grounded theory study to discern what prominent practitioners of academic social media (e.g. Twitter) have encountered in their careers. Participants were recruited via a snowball sampling technique and invited to participate in semi-structured interviews. Three investigators engaged in constant comparative analysis of incoming transcripts. To enhance rigour, we conducted an audit of the analysis and a participant member check. Results: Seventeen emerging influencers in the field of academic social media were recruited. After axial coding, the 30 enablers and 21 barriers to academic social media use were mapped to three spheres of influence: personal, institutional, and virtual. The investigators propose a framework that organizes these enablers and barriers around a tipping point where sustainability becomes possible. Conclusions: Multiple enablers and barriers were described to influence social media users within academic medicine. By organizing these facets into a personal, institutional, and virtual framework along a spectrum, we can begin to understand the underlying structures that potentiate the academic ecosystems in which social media and similar innovations may flourish.Introduction : Alors que le milieu universitaire commence Ă  intĂ©grer les technologies de communication modernes dans ses structures d’enseignement, il existe Ă  la fois des facteurs favorables et des obstacles Ă  l’adoption de ces innovations par les chercheurs. Les premiers adoptants des rĂ©seaux sociaux scientifiques, que ce soit dans un cadre Ă©ducatif, de rĂ©seautage liĂ© Ă  la recherche ou d’application des connaissances, sont sans doute les mieux placĂ©s pour mettre en Ă©vidence aussi bien les facteurs favorables que les facteurs dĂ©favorables prĂ©sents dans leur environnement de travail. MĂ©thodes : Les auteurs ont menĂ© une Ă©tude selon la thĂ©orisatoin ancrĂ©e qui s’inscrit dans un courant constructiviste afin de cibler les Ă©lĂ©ments de l’expĂ©rience d’importants utilisateurs des rĂ©seaux sociaux scientifiques (p. ex. Twitter). Les participants ont Ă©tĂ© recrutĂ©s par Ă©chantillonnage en boule de neige et invitĂ©s Ă  des entretiens semi-structurĂ©s. Trois chercheurs ont analysĂ© les transcriptions reçues selon la mĂ©thode de la comparaison constante. Par souci de rigueur, nous avons procĂ©dĂ© Ă  une vĂ©rification de l’analyse et Ă  un contrĂŽle des participants. RĂ©sultats : Dix-sept influenceurs Ă©mergents dans le domaine des rĂ©seaux sociaux scientifiques ont Ă©tĂ© recrutĂ©s. AprĂšs un codage axial, les 30 catalyseurs et les 21 obstacles Ă  l’utilisation des rĂ©seaux sociaux scientifiques ont Ă©tĂ© mis en correspondance avec trois sphĂšres d’influence : personnelle, institutionnelle et virtuelle. Les chercheurs proposent un cadre qui organise ces catalyseurs et ces obstacles autour d’un point de basculement oĂč la durabilitĂ© devient possible. Conclusions : De multiples facilitateurs et obstacles ont Ă©tĂ© dĂ©crits pour influencer les utilisateurs de rĂ©seaux sociaux dans le domaine de la mĂ©decine universitaire. La classification de ces facteurs sur une Ă©chelle par type de cadre (personnel, institutionnel et virtuel) laisse entrevoir les structures sous-jacentes des Ă©cosystĂšmes universitaires qui sont propices au dĂ©veloppement des rĂ©seaux sociaux et des innovations de ce type

    Using rhythmic nonces for puzzle-based DoS resistance

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    To protect against replay attacks, many Internet proto-cols rely on nonces to guarantee freshness. In practice, the server generates these nonces during the initial hand-shake, but if the server is under attack, resources con-sumed by managing certain protocols can lead to DoS vulnerabilities. To help alleviate this problem, we pro-pose the concept of rhythmic nonces, a cryptographic tool that allows servers to measure request freshness with minimal bookkeeping costs. We explore the impact of this service in the context of a puzzle-based DoS re-sistance scheme we call “SYN puzzles”. Our preliminary results based on mathematical analysis and evaluation of a prototype suggests that our scheme is more resistant than existing techniques. 1

    Soins virtuels dans CanMEDS 2025

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    Novel technique for mode selection in a large-mode-area fiber laser

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    A novel method for selectively exciting a single-spatial-mode (fundamental or higher-order) in a high-power multi-mode fiber laser resonator is presented. Preliminary results for a cladding-pumped Tm-doped silica fiber laser are discussed
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