804 research outputs found

    Post-depositional subsidence of the Avellino tephra marker bed in the Pontine plain (Lazio, Italy):Implications for Early Bronze Age palaeogeographical, water level and relative sea level reconstruction

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    Land subsidence has played and is still playing a significant role in coastal wetlands worldwide and in palaeogeographical reconstructions of such wetlands. The varying thickness of compaction-prone sediments over a stable subsurface is a key factor in determining its magnitude and in locating the most affected areas. In the coastal low-lying Agro Pontino (Lazio, Italy), subsidence of the past 90 years has been mapped using historical elevation data. Due to the fortunate preservation of distal Avellino tephra (AV-tephra, ca. 1900 cal. BCE) within its marshy strata, discovered a decade ago, detailed palaeogeographical reconstruction of the landscape in preparation for an assessment of its land use suitability in the Early Bronze Age (EBA) was possible. Current altitude variations of water-lain tephra in lake areas assumed to be connected necessitated a closer look at its original deposition altitude and the role of post-depositional subsidence. Recent subsidence patterns proved very useful for distinguishing stable from subsidence-prone areas. Two different EBA palaeo lake environments are distinguished: an inland and a near-coastal lake. The AV-tephra altitude variation within these lakes partly marks differential post-depositional subsidence within these lakes. Calculation of initial ripening of tephra-bearing lake deposits on top of shallowly buried Pleistocene ridges allowed for an estimation of original tephra deposition altitudes and associated lake levels. For the inland lake, a wide lake edge zone between 0.5 and 2 m above current sea level (m asl) was reconstructed, where EBA habitation or land use was possible. At the near-coastal lake, a water level of −1.5 to −1.3 m asl at the time of AV-tephra deposition was constrained. Because tephra deposition occurred here just after marine influence ceased, this altitude range is proposed to be a Relative Sea Level (RSL) index point at the time of AV-tephra deposition. The altitude range is in agreement with RSL models for tectonically stable areas in this region. The importance of subsidence in palaeogeographical, water level and RSL reconstructions in the region is stressed

    Evaluation of Model Transformation Approaches for Model Refactoring

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    This paper provides a systematic evaluation framework for comparing model transformation approaches, based upon the ISO/IEC 9126-1 quality characteristics for software systems. We apply this framework to compare five transformation approaches (QVT-R, ATL, Kermeta, UMLRSDS and GrGen.NET) on a complex model refactoring case study: the amalgamation of apparent attribute clones in a class diagram. The case study highlights the problems with the specification and design of the refactoring category of model transformations, and provides a challenging example by which model transformation languages and approaches can be compared. We take into account a wide range of evaluation criteria aspects such as correctness, efficiency, flexibility, interoperability, reusability and robustness, which have not been comprehensively covered by other comparative surveys of transformation approaches. The results show clear distinctions between the capabilities and suitabilities of different approaches to address the refactoring form of transformation problem

    First detection and energy measurement of recoil ions following beta decay in a Penning trap with the WITCH experiment

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    The WITCH experiment (Weak Interaction Trap for CHarged particles) will search for exotic interactions by investigating the beta-neutrino angular correlation via the measurement of the recoil energy spectrum after beta decay. As a first step the recoil ions from the beta-minus decay of 124In stored in a Penning trap have been detected. The evidence for the detection of recoil ions is shown and the properties of the ion cloud that forms the radioactive source for the experiment in the Penning trap are presented.Comment: 9 pages, 6 figures (9 figure files), submitted to European Physical Journal

    Promoting occupational health through gamification and e-coaching: A 5-month user engagement study

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    Social gamification systems have shown potential for promoting healthy lifestyles, but applying them to occupational settings faces unique design challenges. While occupational settings offer natural communities for social interaction, fairness issues due to heterogeneous personal goals and privacy concerns increase the difficulty of designing engaging games. We explored a two-level game-design, where the first level related to achieving personal goals and the second level was a privacy-protected social competition to maximize goal compliance among colleagues. The solution was strengthened by employing occupational physicians who personalized users’ goals and coached them remotely. The design was evaluated in a 5-month study with 53 employees from a Dutch university. Results suggested that the application helped half of the participants to improve their lifestyles, and most appreciated the role of the physician in goal-setting. However, long-term user engagement was undermined by the scalability-motivated design choice of one-way communication between employees and their physician. Implications for social gamification design in occupational health are discussed

    Higher diagnostic accuracy and cost-effectiveness using procalcitonin in the treatment of emergency medicine patients with fever (The HiTEMP study)

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    __Background:__ Fever is a common symptom in the emergency department(ED). Fever can be caused by bacterial infections, which are treated with antibiotics. Often, bacterial infections cannot be ruled out in the ED using standard diagnostics, and empiric antibiotic treatment is started. Procalcitonin(PCT) is a biomarker for bacterial infections, but its role in an undifferentiated ED population remains unclear. We hypothesize that PCT-guided therapy may reduce antibiotics prescription in undifferentiated febrile ED patients. The primary objectives of this study are to determine a) the efficacy, b) the safety of PCT-guided therapy, and c) the accuracy of the biomarker PCT for bacterial infections. The secondary objective is to study the cost-effectiveness of PCT-guided therapy. __Methods/design:__ This is a multicenter noninferiority randomized controlled trial. All adult ED patients with fever(≥38.2 °C) are randomized between standard care with and without the addition of a PCT level, after written informed consent. a) For efficacy, the reduction of patients receiving antibiotics is calculated, using a superiority analysis: differences between the PCT-guided group and control group are assessed using a Fisher's exact test, and a multivariable logistic regression analysis to account for the effects of demographic and medical variables on the percentage of febrile patients receiving antibiotics. b) Safety consists of a composite endpoint, defined as mortality, intensive care admission and ED return visit within 14 days. Noninferiority of PCT will be tested using a one-sided 95 % confidence interval for the difference in the composite safety endpoint between the PCT-guided and control groups using a noninferiority margin of 7.5 %. c) Accuracy of PCT and CRP for the diagnosis of bacterial infections will be reported, using the sensitivity, specificity, and the area under the receiver-operating-characteristic curve in the definitive diagnosis of bacterial infections. The sample size is 550 patients, which was calculated using a power analysis for all primary objectives. Enrollment of patients started in August 2014 and will last 2 years. __Discussion:__ PCT may offer a more tailor-made treatment to the individual ED patient with fever. Prospective costs analyses will reveal the economic consequences of implementing PCT-guided therapy in the ED. This trial is registered in the Dutch trial register:NTR4949
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