69,866 research outputs found

    Terrigenous sediment-dominated reef platform infilling: an unexpected precursor to reef island formation and a test of the reef platform size-island age model in the Pacific

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    Low-lying coral reef islands are considered highly vulnerable to climate change, necessitating an improved understanding of when and why they form, and how the timing of formation varies within and among regions. Several testable models have been proposed that explain inter-regional variability as a function of sea-level history and, more recently, a reef platform size model has been proposed from the Maldives (central Indian Ocean) to explain intra-regional (intra-atoll) variability. Here we present chronostratigraphic data from Pipon Island, northern Great Barrier Reef (GBR), enabling us to test the applicability of existing regional island evolution models, and the platform size control hypothesis in a Pacific context. We show that reef platform infilling occurred rapidly (~4–5 mm yr−1) under a “bucket-fill” type scenario. Unusually, this infilling was dominated by terrigenous sedimentation, with platform filling and subsequent reef flat formation complete by ~5000 calibrated years BP (cal BP). Reef flat exposure as sea levels slowly fell post highstand facilitated a shift towards intertidal and subaerial-dominated sedimentation. Our data suggest, however, a lag of ~1500 yr before island initiation (at ~3200 cal BP), i.e. later than that reported from smaller and more evolutionarily mature reef platforms in the region. Our data thus support: (1) the hypothesis that platform size acts to influence the timing of platform filling and subsequent island development at intra-regional scales; and (2) the hypothesis that the low wooded islands of the northern GBR conform to a model of island formation above an elevated reef flat under falling sea levels

    \u3cem\u3ePer Ardua Ad Astra\u3c/em\u3e: A Concicise Guide to Canadian Personnel Records and RCAF Service Information of the Second World War

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    The motto of the Royal Canadian Air Force—per ardua ad astra—through adversity to the stars—might also serve as an apt expression when beginning research on individual Canadian airmen or airwomen of the Second World War. Without a guiding-hand, the first-time researcher is likely to experience some considerable “adversity” before locating their “stars.” This note introduces the key records and published sources for documenting those individuals who served with the Royal Canadian Air Force during the Second World War, as well as directions for locating the records of those Canadians who served in related air elements during the conflict. Many archival records and library sources give some information about these individuals; this note is limited to official records, or to those records compiled from official sources, that are held by the major Canadian and Commonwealth institutions which have the mandate to provide such essential wartime documentation

    Researching characteristics of people moving into and out of the Western Bay of Plenty and Tauranga districts: Some methodological issues

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    The Western Bay of Plenty (WBOP), has one of the fastest growing populations in New Zealand. This Discussion Paper details a methodology that has been used to conduct a survey of people moving into and out of the Western Bay of Plenty between October 2000 and September 2001

    Funding the Future: Resources for Adolescent Reproductive and Sexual Health Programs in Developing Countries

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    Provides a directory of over 90 foundations, agencies, and organizations that support adolescent reproductive and sexual health related programs in developing countries, through direct and/or indirect financing, technical assistance, and information

    Corrosion Damage Analysis and Material Characterization of Sherman and Centaur - The Historic Military Tanks

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    A study of corrosion damage and material characterization of two historic military tanks, the Sherman and Centaur is reported. Experiments were conducted to analyse surface corrosion and corrosion propagation from surface to sub-surface. Significant surface corrosion was found, this phenomenon was further facilitated by delamination failure mechanisms. Corrosion depth for the Sherman was approximately 110 µm, where sulphide inclusions were detected in the sub-surface analysis. The Centaur’s analysis showed corrosion pits at 100 µm depth. These pits possess random geometrical configurations with evidence of sulfur, sodium and calcium

    Analyzing Social and Stylometric Features to Identify Spear phishing Emails

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    Spear phishing is a complex targeted attack in which, an attacker harvests information about the victim prior to the attack. This information is then used to create sophisticated, genuine-looking attack vectors, drawing the victim to compromise confidential information. What makes spear phishing different, and more powerful than normal phishing, is this contextual information about the victim. Online social media services can be one such source for gathering vital information about an individual. In this paper, we characterize and examine a true positive dataset of spear phishing, spam, and normal phishing emails from Symantec's enterprise email scanning service. We then present a model to detect spear phishing emails sent to employees of 14 international organizations, by using social features extracted from LinkedIn. Our dataset consists of 4,742 targeted attack emails sent to 2,434 victims, and 9,353 non targeted attack emails sent to 5,912 non victims; and publicly available information from their LinkedIn profiles. We applied various machine learning algorithms to this labeled data, and achieved an overall maximum accuracy of 97.76% in identifying spear phishing emails. We used a combination of social features from LinkedIn profiles, and stylometric features extracted from email subjects, bodies, and attachments. However, we achieved a slightly better accuracy of 98.28% without the social features. Our analysis revealed that social features extracted from LinkedIn do not help in identifying spear phishing emails. To the best of our knowledge, this is one of the first attempts to make use of a combination of stylometric features extracted from emails, and social features extracted from an online social network to detect targeted spear phishing emails.Comment: Detection of spear phishing using social media feature
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