115 research outputs found

    Identification of earthquake precursors in the hydrogeochemical and geoacoustic data for the Kamchatka peninsula by flicker-noise spectroscopy

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    A phenomenological systems approach for identifying potential precursors in multiple signals of different types for the same local seismically active region is proposed based on the assumption that a large earthquake may be preceded by a system reconfiguration (preparation) at different time and space scales. A nonstationarity factor introduced within the framework of flicker-noise spectroscopy, a statistical physics approach to the analysis of time series, is used as the dimensionless criterion for detecting qualitative (precursory) changes within relatively short time intervals in arbitrary signals. Nonstationarity factors for chlorine-ion concentration variations in the underground water of two boreholes on the Kamchatka peninsula and geacoustic emissions in a deep borehole within the same seismic zone are studied together in the time frame around a large earthquake on October 8, 2001. It is shown that nonstationarity factor spikes (potential precursors) take place in the interval from 70 to 50 days before the earthquake for the hydrogeochemical data and at 29 and 6 days in advance for the geoacoustic data.Comment: 8 pages, 4 figures; to be published in Nat. Hazards Earth Syst. Sc

    Scintillation counter with MRS APD light readout

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    START, a high-efficiency and low-noise scintillation detector for ionizing particles, was developed for the purpose of creating a high-granular system for triggering cosmic muons. Scintillation light in START is detected by MRS APDs (Avalanche Photo-Diodes with Metal-Resistance-Semiconductor structure), operated in the Geiger mode, which have 1 mm^2 sensitive areas. START is assembled from a 15 x 15 x 1 cm^3 scintillating plastic plate, two MRS APDs and two pieces of wavelength-shifting optical fiber stacked in circular coils inside the plastic. The front-end electronic card is mounted directly on the detector. Tests with START have confirmed its operational consistency, over 99% efficiency of MIP registration and good homogeneity. START demonstrates a low intrinsic noise of about 10^{-2} Hz. If these detectors are to be mass-produced, the cost of a mosaic array of STARTs is estimated at a moderate level of 2-3 kUSD/m^2.Comment: 6 pages, 5 figure

    START as the detector of choice for large-scale muon triggering systems

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    Further progress in building high-granular large-scale systems based on Scintillation Tiles with MRS APD light readout (START) became possible thanks to the creation of an improved version of MRS APD. The cost of the system may now be significantly reduced by using inexpensive extruded scintillator. More than 160 START samples were assembled based on this design modification and proved to possess 100% MIP detection efficiency and the intrinsic noise rate of less than 0.08 Hz. Long-term stability of START characteristics was confirmed after 3.5 months of operation

    Cross-Correlation Earthquake Precursors in the Hydrogeochemical and Geoacoustic Signals for the Kamchatka Peninsula

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    We propose a new type of earthquake precursor based on the analysis of correlation dynamics between geophysical signals of different nature. The precursor is found using a two-parameter cross-correlation function introduced within the framework of flicker-noise spectroscopy, a general statistical physics approach to the analysis of time series. We consider an example of cross-correlation analysis for water salinity time series, an integral characteristic of the chemical composition of groundwater, and geoacoustic emissions recorded at the G-1 borehole on the Kamchatka peninsula in the time frame from 2001 to 2003, which is characterized by a sequence of three groups of significant seismic events. We found that cross-correlation precursors took place 27, 31, and 35 days ahead of the strongest earthquakes for each group of seismic events, respectively. At the same time, precursory anomalies in the signals themselves were observed only in the geoacoustic emissions for one group of earthquakes.Comment: 21 pages, 5 figures, 1 table; to be published in "Acta Geophysica". arXiv admin note: substantial text overlap with arXiv:1101.147

    К МЕТОДИКЕ ОЦЕНКИ ПЕРФУЗИИ МИОКАРДА ЛЕВОГО ЖЕЛУДОЧКА ПРИ ИНФАРКТЕ МИОКАРДА С ПОМОЩЬЮ ОДНОФОТОННОЙ ЭМИССИОННОЙ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ

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    SUMMARY. On the basis of single photon emission computed tomography of the myocardium (SPECT) with Technetril 99mTc performed in 81 patients with myocardial infarction (MI), we confirmed the proportion of myocardial segments of the left ventricle (LV) with varying degrees of RP inclusion and, therefore, with varying degrees of perfusion impairment. In 75% of patients, reduction of hypoperfusion area in the remote period after myocardial infarction has been revealed compared to the acute period. The relation between slow ECG evolution with the severe impairment of left ventricular myocardial perfusion has been showed. The relation between the degree of impairment of LV myocardial perfusion (by SPECT) and its contraction (according to the two-dimensional echocardiogram) has been revealed. It is shown that one of the leading factors in the restoration of myocardial perfusion is the time of intracoronary intervention. РЕЗЮМЕ. На основании проведения у 81 больного инфарктом миокарда (ИМ) перфузионной однофотонной эмиссионной компьютерной томографии (ОФЭКТ) миокарда с 99mTc-технетрилом уточнено соотношение сегментов миокарда левого желудочка (ЛЖ) с разной степенью включения радиофармпрепарата и, следовательно, с разной степенью нарушения перфузии. У 75% пациентов установлено сокращение площади гипоперфузии в отдаленный период инфаркта по сравнению с острым. Продемонстрирована связь замедленной ЭКГ-эволюции ИМ с глубокими расстройствами перфузии миокарда ЛЖ. Выявлена взаимосвязь степени нарушения перфузии миокарда ЛЖ (по данным ОФЭКТ) и его сократимости (по данным двухмерной Эхо-КГ). Показано, что одним из ведущих факторов восстановления перфузии миокарда является время выполнения внутрико- ронарного вмешательства.

    ЧТО ИЗМЕНЯЕТСЯ В ПЕРФУЗИИ И ФУНКЦИИ МИОКАРДА ПОСЛЕ  ПОЗДНЕЙ РЕВАСКУЛЯРИЗАЦИИ ОСТРОГО ИНФАРКТА МИОКАРДА?

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    Aim. To determine the influence of the time gap between acute myocardial infarction with ST-segment elevation and intracoronary intervention performed later than 2.5 hours on myocardium, we studied indicators of perfusion over time with an aid of SPECT, including intraventricular asynchrony (2–4 days and 6–8 months after stent installation).Materials and method. We observed 22 patients with multivessel coronary lesion. The Russian program with the analysis of perfusion, function and the phase images was used in SPECT synchronized with ECG.Results. Showed that the time gap prior to coronary intervention in the acute phase of myocardial infarction may be directly connected with the increase in impaired perfusion during the end-systole and the severity of pathological intraventricular asynchrony without ECG signs. All patients had significantly decreased wall mobility and intraventricular asynchrony together with increased R-R interval in the late period (after 6–8 months) independently from the coronary intervention time. In patients of group 1 (coronary intervention within 6 hours), focal transmural lesions of myocardium significantly decreased.Conclusion. Late revascularization help decrease intraventricular asynchrony reducing the risk of heart failure in future. С целью определения влияния на миокард сроков от острого инфаркта миокарда с подъемом сегмента ST до внутрикоронарного вмешательства, выполненного позднее 2,5 ч, с помощью однофотонной эмиссионной компьютерной томографии (ОФЭКТ) в динамике (на 2–4-е сут и через 6–8 мес после стентирования) изучены параметры перфузии и функции, в том числе внутрижелудочковая асинхрония.Материал и методы. Обследованы 22 пациента с многососудистым поражением коронарного русла. При ОФЭКТ, синхронизированной с электрокардиографией (ЭКГ), использовали отечественную программу с анализом показателей перфузии, функции и фазовых изображений.Результаты. Показано, что время до внутрикоронарного вмешательства в остром периоде инфаркта миокарда может иметь прямую связь с увеличением размеров нарушенной перфузии в конечную систолу и с выраженностью патологической внутрижелудочковой асинхронии миокарда без признаков асинхронии на ЭКГ. Независимо от времени внутрикоронарного вмешательства у всех больных в отдаленном периоде (через 6–8 мес) зарегистрировано значимое уменьшение движения стенки, показателей внутрижелудочковой асинхронии и увеличение интервала R–R. При сравнении исходных и отсроченных данных ОФЭКТ у больных 1-й группы (время менее 6 ч) статистически значимо уменьшались размеры трансмурального очагового поражения миокарда левого желудочка.Заключение. Поздняя реваскуляризация помогает уменьшить внутрижелудочковую асинхронию, снижая риск развития сердечной недостаточности.

    “I have no clue what I drunk last night” Using Smartphone technology to compare in-vivo and retrospective self-reports of alcohol consumption.

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    This research compared real-time measurements of alcohol consumption with retrospective accounts of alcohol consumption to examine possible discrepancies between, and contextual influences on, the different accounts.Building on previous investigations, a specifically designed Smartphone technology was utilized to measure alcohol consumption and contextual influences in de facto real-time. Real-time data (a total of 10,560 data points relating to type and number of drinks and current social / environmental context) were compared with daily and weekly retrospective accounts of alcohol consumption.Participants reported consuming more alcoholic drinks during real-time assessment than retrospectively. For daily accounts a higher number of drinks consumed in real-time was related to a higher discrepancy between real-time and retrospective accounts. This effect was found across all drink types but was not shaped by social and environmental contexts. Higher in-vivo alcohol consumption appeared to be related to a higher discrepancy in retrospectively reported weekly consumption for alcohol beverage types other than wine. When including contextual factors into the statistical models, being with two or more friends (as opposed to being alone) decreased the discrepancy between real-time and retrospective reports, whilst being in the pub (relative to being at home) was associated with greater discrepancies.Overall, retrospective accounts may underestimate the amount of actual, real-time alcohol consumed. Increased consumption may also exacerbate differences between real-time and retrospective accounts. Nonetheless, this is not a global effect as environmental and social contexts interact with the type of alcohol consumed and the time frame given for reporting (weekly vs. daily retrospective). A degree of caution therefore appears warranted with regards to the use of retrospective self-report methods of recording alcohol consumption. Whilst real-time sampling is unlikely to be completely error free, it may be better able to account for social and environmental influences on self-reported consumption

    EEG Biofeedback as a Treatment for Substance Use Disorders: Review, Rating of Efficacy, and Recommendations for Further Research

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    Electroencephalographic (EEG) biofeedback has been employed in substance use disorder (SUD) over the last three decades. The SUD is a complex series of disorders with frequent comorbidities and EEG abnormalities of several types. EEG biofeedback has been employed in conjunction with other therapies and may be useful in enhancing certain outcomes of therapy. Based on published clinical studies and employing efficacy criteria adapted by the Association for Applied Psychophysiology and Biofeedback and the International Society for Neurofeedback and Research, alpha theta training—either alone for alcoholism or in combination with beta training for stimulant and mixed substance abuse and combined with residential treatment programs, is probably efficacious. Considerations of further research design taking these factors into account are discussed and descriptions of contemporary research are given

    ATLAS detector and physics performance: Technical Design Report, 1

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