1,038 research outputs found

    Die approximative Inverse als Rekonstruktionsmethode in der Röntgen-Computertomographie

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    Применение метода аналитических сетей для оптимизации процесса выбора стратегии развития пассажирского автотранспортного предприятия

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    В статье обозначена проблема снижения рентабельности пассажирских автотранспортных предприятий и связанные с этим сложности по реализации процедуры стратегического прогнозирования и управления предприятием. Обосновано использование метода аналитических сетей в модели поддержки принятия решений при управлении стратегией автотранспортного предприятия, представленной в работе [1], в качестве инструмента, позволяющего формализовать экспертные знания на основных этапах оценки и выбора проектов стратегического развития. Описаны основные шаги и приведены результаты расчета алгоритма метода аналитических сетей в рамках данной модели.The article outlines the problem of reducing the profitability of passenger motor transport enterprises and the associated difficulties in implementing the procedure of strategic forecasting and enterprise management. The use of the method of analytical networks in the model of decision support in managing the strategy of a trucking enterprise presented in [1] is substantiated as a tool that allows to formalize expert knowledge at the main stages of evaluation and selection of projects for strategic development. The main steps and calculations of the algorithm algorithm for analytical networks within the framework of this model are described

    Исследование загрязненности водных объектов техногенными радионуклидами

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    Работа посвящена исследованию водных объектов, которые подвергаются негативному воздействию со стороны химического комбината. В ходе работы выявлены радионуклиды, содержащиеся в воде, а также сделан вывод о вкладе этих радионуклидов в загрязнение р.Томи.The work is devoted to the study of water objects, which are exposed to negative effects from the chemical plant. The research identified radionuclides contained in water, and also concluded the contribution of these radionuclides to the pollution of the Tom river

    Approximate inverse meets local tomography

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    Noninvasive Detection of Fibrosis Applying Contrast-Enhanced Cardiac Magnetic Resonance in Different Forms of Left Ventricular Hypertrophy Relation to Remodeling

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    ObjectivesWe aimed to evaluate the incidence and patterns of late gadolinium enhancement (LGE) in different forms of left ventricular hypertrophy (LVH) and to determine their relation to severity of left ventricular (LV) remodeling.BackgroundLeft ventricular hypertrophy is an independent predictor of cardiac mortality. The relationship between LVH and myocardial fibrosis as defined by LGE cardiovascular magnetic resonance (CMR) is not well understood.MethodsA total of 440 patients with aortic stenosis (AS), arterial hypertension (AH), or hypertrophic cardiomyopathy (HCM) fulfilling echo criteria of LVH underwent CMR with assessment of LV size, weight, function, and LGE. Patients with increased left ventricular mass index (LVMI) resulting in global LVH in CMR were included in the study.ResultsCriteria were fulfilled by 83 patients (56 men, age 57 ± 14 years; AS, n = 21; AH, n = 26; HCM, n = 36). Late gadolinium enhancement was present in all forms of LVH (AS: 62%, AH: 50%; HCM: 72%, p = NS) and was correlated with LVMI (r = 0.237, p = 0.045). There was no significant relationship between morphological obstruction and LGE. The AS subjects with LGE showed higher LV end-diastolic volumes than those without (1.0 ± 0.2 ml/cm vs. 0.8 ± 0.2 ml/cm, p < 0.015). Typical patterns of LGE were observed in HCM but not in AS and AH.ConclusionsFibrosis as detected by CMR is a frequent feature of LVH, regardless of its cause, and depends on the severity of LV remodeling. As LGE emerges as a useful tool for risk stratification also in nonischemic heart diseases, our findings have the potential to individualize treatment strategies

    An open-source software tool for the generation of relaxation time maps in magnetic resonance imaging

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    BACKGROUND: In magnetic resonance (MR) imaging, T1, T2 and T2* relaxation times represent characteristic tissue properties that can be quantified with the help of specific imaging strategies. While there are basic software tools for specific pulse sequences, until now there is no universal software program available to automate pixel-wise mapping of relaxation times from various types of images or MR systems. Such a software program would allow researchers to test and compare new imaging strategies and thus would significantly facilitate research in the area of quantitative tissue characterization. RESULTS: After defining requirements for a universal MR mapping tool, a software program named MRmap was created using a high-level graphics language. Additional features include a manual registration tool for source images with motion artifacts and a tabular DICOM viewer to examine pulse sequence parameters. MRmap was successfully tested on three different computer platforms with image data from three different MR system manufacturers and five different sorts of pulse sequences: multi-image inversion recovery T1; Look-Locker/ TOMROP T1; modified Look-Locker inversion recovery (MOLLI) T1; single-echo T2/ T2*; and multi-echo T2/ T2*. Computing times varied between 2 and 113 seconds. Estimates of relaxation times compared favorably to those obtained from non-automated curve fitting. Completed maps were exported in DICOM format and could be read in standard software packages used for analysis of clinical and research MR data. CONCLUSIONS: MRmap is a flexible cross-platform research tool that enables accurate mapping of relaxation times from various pulse sequences. The software allows researchers to optimize quantitative MR strategies in a manufacturer-independent fashion. The program and its source code were made available as open-source software on the internet
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