613 research outputs found

    COLOPHON 2013

    No full text
    International audienceIn 2010 the Mimar Sinan University of Istanbul started a research project on the Ionian town of Colophon which is conducted in close collaboration with the University of Vienna [1]. It aims at the exploration of the ancient urban area as well as on the distribution of the necropoleis. For the campaign of the year 2013 the Austrian research team concentrated on the following topics [2]. 1. Survey in the area of the ancient city This year, the main focus of the investigations in the area within the fortification walls was laid on the exploration of the urbanistic organisation of the city by magnetic survey and by ground penetrating radar. For this purpose two areas were chosen. The first area consisted of fields in the plain between the brooks Kabaklidere and Kurudere in the north eastern quarters of the ancient city. Here the existence of houses has been proven by excavations by the museum of Izmir about 10–15 years ago. The remains of walls were also visible in several trenches opened by illegal diggers both on the plains and in the forested area near the slopes of the surrounding hills. The geophysical prospection confirmed the assumed existence of several buildings and streets in the area. In addition we conducted an extensive survey in adjacent fields and collected pottery from the holes dug by illegal diggers. The finds included roof tiles and a small amount of pottery with a chronological range from the 6 th to the 4 th c. BC. A detailed documentation of the present land-use and land-division of this area, already begun in 2012, was continued with the aim of a diachronical understanding of the landscape's historical development. This included the description of modern features in the fields as well as interviews with owners and tenants. The second area chosen for a geophysical prospection is situated to the south of the Halil Ağa Tepesi, where W. Höpfner proposed to locate the ancient agora [3]. Both magnetic survey and ground penetrating radar prospections were carried out here. Further examination of the data is currently being carried out. The exemplary geophysical prospection will give important insights into the organisation and layou

    Run Generation Revisited: What Goes Up May or May Not Come Down

    Full text link
    In this paper, we revisit the classic problem of run generation. Run generation is the first phase of external-memory sorting, where the objective is to scan through the data, reorder elements using a small buffer of size M , and output runs (contiguously sorted chunks of elements) that are as long as possible. We develop algorithms for minimizing the total number of runs (or equivalently, maximizing the average run length) when the runs are allowed to be sorted or reverse sorted. We study the problem in the online setting, both with and without resource augmentation, and in the offline setting. (1) We analyze alternating-up-down replacement selection (runs alternate between sorted and reverse sorted), which was studied by Knuth as far back as 1963. We show that this simple policy is asymptotically optimal. Specifically, we show that alternating-up-down replacement selection is 2-competitive and no deterministic online algorithm can perform better. (2) We give online algorithms having smaller competitive ratios with resource augmentation. Specifically, we exhibit a deterministic algorithm that, when given a buffer of size 4M , is able to match or beat any optimal algorithm having a buffer of size M . Furthermore, we present a randomized online algorithm which is 7/4-competitive when given a buffer twice that of the optimal. (3) We demonstrate that performance can also be improved with a small amount of foresight. We give an algorithm, which is 3/2-competitive, with foreknowledge of the next 3M elements of the input stream. For the extreme case where all future elements are known, we design a PTAS for computing the optimal strategy a run generation algorithm must follow. (4) Finally, we present algorithms tailored for nearly sorted inputs which are guaranteed to have optimal solutions with sufficiently long runs

    COLOPHON 2013

    No full text
    International audienceIn 2010 the Mimar Sinan University of Istanbul started a research project on the Ionian town of Colophon which is conducted in close collaboration with the University of Vienna [1]. It aims at the exploration of the ancient urban area as well as on the distribution of the necropoleis. For the campaign of the year 2013 the Austrian research team concentrated on the following topics [2]. 1. Survey in the area of the ancient city This year, the main focus of the investigations in the area within the fortification walls was laid on the exploration of the urbanistic organisation of the city by magnetic survey and by ground penetrating radar. For this purpose two areas were chosen. The first area consisted of fields in the plain between the brooks Kabaklidere and Kurudere in the north eastern quarters of the ancient city. Here the existence of houses has been proven by excavations by the museum of Izmir about 10–15 years ago. The remains of walls were also visible in several trenches opened by illegal diggers both on the plains and in the forested area near the slopes of the surrounding hills. The geophysical prospection confirmed the assumed existence of several buildings and streets in the area. In addition we conducted an extensive survey in adjacent fields and collected pottery from the holes dug by illegal diggers. The finds included roof tiles and a small amount of pottery with a chronological range from the 6 th to the 4 th c. BC. A detailed documentation of the present land-use and land-division of this area, already begun in 2012, was continued with the aim of a diachronical understanding of the landscape's historical development. This included the description of modern features in the fields as well as interviews with owners and tenants. The second area chosen for a geophysical prospection is situated to the south of the Halil Ağa Tepesi, where W. Höpfner proposed to locate the ancient agora [3]. Both magnetic survey and ground penetrating radar prospections were carried out here. Further examination of the data is currently being carried out. The exemplary geophysical prospection will give important insights into the organisation and layou

    Combined Collection and Analysis of Inorganic and Organic Gunshot Residues.

    Get PDF
    Gunshot residue (GSR) analysis and their interpretation provide crucial information on a criminal investigation involving the use of firearms. To date, several approaches have been proposed for the implementation of a combined sampling and analysis of inorganic (IGSR) and organic GSR (OGSR). However, it is not clear at this stage if concurrent analyses of both types of residue might be detrimental to the analysis of IGSR currently applied in forensic laboratories. Thus, this work aims to compare and evaluate three different protocols for the combined collection and analysis of IGSR and OGSR. These methods, respectively, involve the use of a modified stub (with two halves, one for the detection of IGSR and the other for the analysis of OGSR); the sequential recovery of GSR with two stubs mounted with different adhesives (double-sided carbon tape and Tesa® TACK) and the sequential analysis of IGSR and OGSR from a single carbon stub following carbon deposition. The detection of IGSR was carried out using SEM-EDX, while OGSR analysis was performed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Obtained results for experiments performed using Geco Sinoxid <sup>®</sup> ammunition indicated that sequential analysis was the most suitable protocol for the combined collection and analysis of both IGSR and OGSR. A higher number of inorganic (characteristic and consistent) particles and higher concentrations of ethylcentralite, N-nitrosodiphenylamine, diphenylamine, and nitroglycerin were recovered with this method

    Prevalence of Steatosis Hepatis in the Eurotransplant Region: Impact on Graft Acceptance Rates

    Get PDF
    Due to the shortage of liver allografts and the rising prevalence of fatty liver disease in the general population, steatotic liver grafts are considered for transplantation.This condition is an important risk factor for the outcome after transplantation.We here analyze the characteristics of the donor pool offered to the Charité –Universitätsmedizin Berlin from 2010 to 2016 with respect to liver allograft nonacceptance and steatosis hepatis. Of the 2653 organs offered to our center, 19.9% (n=527) were accepted for transplantation, 58.8% (n=1561) were allocated to other centers, and 21.3% (n = 565) were eventually discarded from transplantation. In parallel to an increase of the incidence of steatosis hepatis in the donor pool from 20% in 2010 to 30% in 2016, the acceptance rates for steatotic organs increased in our center from 22.3% to 51.5% in 2016 (p 0.001) having less than 30% macrovesicular steatosis hepatis. However, by 2016, the number of canceled transplantations due to higher grades of steatosis hepatis had significantly increased from 14.7% (n = 15) to 63.6% (42; p < 0.001).The rising prevalence of steatosis hepatis in the donor pool has led to higher acceptance rates of steatotic allografts. Nonetheless, steatosis hepatis remains a predominant phenomenon in discarded organs necessitating future concepts such as organ reconditioning to increase graft utilization

    Early Allograft Dysfunction Increases Hospital Associated Costs After Liver Transplantation—A Propensity Score–Matched Analysis

    Get PDF
    Concepts to ameliorate the continued mismatch between demand for liver allografts and supply include the acceptance of allografts that meet extended donor criteria (ECD). ECD grafts are generally associated with an increased rate of complications such as early allograft dysfunction (EAD). The costs of liver transplantation for the health care system with respect to specific risk factors remain unclear and are subject to change. We analyzed 317 liver transplant recipients from 2013 to 2018 for outcome after liver transplantation and hospital costs in a German transplant center. In our study period, 1-year survival after transplantation was 80.1% (95% confidence interval: 75.8%-84.6%) and median hospital stay was 33 days (interquartile rage: 24), with mean hospital costs of euro115,924 (SD euro113,347). There was a positive correlation between costs and laboratory Model for End-Stage Liver Disease score (r(s) = 0.48, P < 0.001), and the development of EAD increased hospital costs by euro26,229. ECD grafts were not associated with a higher risk of EAD in our cohort. When adjusting for recipient-associated risk factors such as laboratory Model for End-Stage Liver Disease score, recipient age, and split liver transplantation with propensity score matching, only EAD and cold ischemia increased total costs. Conclusion: Our data show that EAD leads to significantly higher hospital costs for liver transplantation, which are primarily attributed to recipient health status. Strategies to reduce the incidence of EAD are needed to control costs in liver transplantation

    Ex vivo machine perfusion: current applications and future directions in liver transplantation

    Get PDF
    Background: Liver transplantation is the only curative treatment option for end-stage liver disease; however, its use remains limited due to a shortage of suitable organs. In recent years, ex vivo liver machine perfusion has been introduced to liver transplantation, as a means to expand the donor organ pool. Purpose: To present a systematic review of prospective clinical studies on ex vivo liver machine perfusion, in order to assess current applications and highlight future directions. Methods: A systematic literature search of both PubMed and ISI web of science databases as well as the ClinicalTrials.gov registry was performed. Results: Twenty-one articles on prospective clinical trials on ex vivo liver machine perfusion were identified. Out of these, eight reported on hypothermic, eleven on normothermic, and two on sequential perfusion. These trials have demonstrated the safety and feasibility of ex vivo liver machine perfusion in both standard and expanded criteria donors. Currently, there are twelve studies enrolled in the clinicaltrials.gov registry, and these focus on use of ex vivo perfusion in extended criteria donors and declined organs. Conclusion: Ex vivo liver machine perfusion seems to be a suitable strategy to expand the donor pool for liver transplantation and holds promise as a platform for reconditioning diseased organs
    corecore