2016-03-01
each IDF curve and subsequently used to force a calibrated and validated precipitation - runoff model. Probability-based, risk-informed hydrologic...ERDC/CHL CHETN-X-2 March 2016 Approved for public release; distribution is unlimited. Bayesian Inference of Nonstationary Precipitation Intensity...based means by which to develop local precipitation Intensity-Duration-Frequency (IDF) curves using historical rainfall time series data collected for
Liew, San Chuin; Raghavan, Srivatsan V.; Liong, Shie-Yui
2014-12-01
The impact of a changing climate is already being felt on several hydrological systems both on a regional and sub-regional scale of the globe. Southeast Asia is one of the regions strongly affected by climate change. With climate change, one of the anticipated impacts is an increase in the intensity and frequency of extreme rainfall which further increase the region's flood catastrophes, human casualties and economic loss. Optimal mitigation measures can be undertaken only when stormwater systems are designed using rainfall Intensity-Duration-Frequency (IDF) curves derived from a long and good quality rainfall data. Developing IDF curves for the future climate can be even more challenging especially for ungauged sites. The current practice to derive current climate's IDF curves for ungauged sites is, for example, to `borrow' or `interpolate' data from regions of climatologically similar characteristics. Recent measures to derive IDF curves for present climate was performed by extracting rainfall data from a high spatial resolution Regional Climate Model driven by ERA-40 reanalysis dataset. This approach has been demonstrated on an ungauged site (Java, Indonesia) and the results were quite promising. In this paper, the authors extend the application of the approach to other ungauged sites particularly in Peninsular Malaysia. The results of the study undoubtedly have significance contribution in terms of local and regional hydrology (Malaysia and Southeast Asian countries). The anticipated impacts of climate change especially increase in rainfall intensity and its frequency appreciates the derivation of future IDF curves in this study. It also provides policy makers better information on the adequacy of storm drainage design, for the current climate at the ungauged sites, and the adequacy of the existing storm drainage to cope with the impacts of climate change.
Ragno, Elisa; AghaKouchak, Amir; Love, Charlotte A.; Cheng, Linyin; Vahedifard, Farshid; Lima, Carlos H. R.
2018-03-01
During the last century, we have observed a warming climate with more intense precipitation extremes in some regions, likely due to increases in the atmosphere's water holding capacity. Traditionally, infrastructure design and rainfall-triggered landslide models rely on the notion of stationarity, which assumes that the statistics of extremes do not change significantly over time. However, in a warming climate, infrastructures and natural slopes will likely face more severe climatic conditions, with potential human and socioeconomical consequences. Here we outline a framework for quantifying climate change impacts based on the magnitude and frequency of extreme rainfall events using bias corrected historical and multimodel projected precipitation extremes. The approach evaluates changes in rainfall Intensity-Duration-Frequency (IDF) curves and their uncertainty bounds using a nonstationary model based on Bayesian inference. We show that highly populated areas across the United States may experience extreme precipitation events up to 20% more intense and twice as frequent, relative to historical records, despite the expectation of unchanged annual mean precipitation. Since IDF curves are widely used for infrastructure design and risk assessment, the proposed framework offers an avenue for assessing resilience of infrastructure and landslide hazard in a warming climate.
Directory of Open Access Journals (Sweden)
Célio Orli Cardoso
2014-04-01
Full Text Available The objective of this work was to analyze the frequency distribution and intensity temporal variability of intense rainfall for Lages/SC from diary pluviograph data. Data on annual series of maximum rainfalls from rain gauges of the CAV-UDESC Weather Station in Lages/SC were used from 2000 to 2009. Gumbel statistic distribution was applied in order to obtain the rainfall height and intensity in the following return periods: 2, 5, 10, 15 and 20 years. Results showed intensity-duration-frequency curves (I-D-F for those return periods, as well as I-D-F equations: i=2050.Tr0,20.(t+30-0,89, where i was the intensity, Tr was the rainfall return periods and t was the rainfall duration. For the intensity of temporal variability pattern along of the rainfall duration time, the convective, or advanced pattern was the predominant, with larger precipitate rainfalls in the first half of the duration. The same pattern presented larger occurrences in the spring and summer stations.
Precipitation intensity-duration-frequency curves and their uncertainties for Ghaap plateau
Directory of Open Access Journals (Sweden)
C.M. Tfwala
2017-01-01
Full Text Available Engineering infrastructures such as stormwater drains and bridges are commonly designed using the concept of Intensity-Duration-Frequency (IDF curves, which assume that the occurrence of precipitation patterns and distributions are spatially similar within the drainage area and remain unchanged throughout the lifespan of the infrastructures (stationary. Based on the premise that climate change will alter the spatial and temporal variability of precipitation patterns, inaccuracy in the estimation of IDF curves may occur. As such, prior to developing IDF curves, it is crucial to analyse trends of annual precipitation maxima. The objective of this study was to estimate the precipitation intensities and their uncertainties (lower and upper limits for durations of 0.125, 0.25, 0.5, 1, 2, 4, and 6 h and return periods of 2, 10, 25, 50 and 100 years in the Ghaap plateau, Northern Cape Province, South Africa using the Generalized Extreme Value (GEV distribution. The annual precipitation maxima were extracted from long-term (1918–2014 precipitation data for four meteorological stations (Postmasburg, Douglas, Kuruman and Groblershoop sourced from the South African Weather Services (SAWS. On average, the estimated extreme precipitation intensities for the plateau ranged from 4.2 mm/h for 6 h storm duration to 55.8 mm/h for 0.125 h at 2 years return period. At 100 year return period, the intensity ranged from 13.3 mm/h for 6 h duration to 175.5 mm/h for the duration of 0.125 h. The lower limit of uncertainty ranged from 11.7% at 2 years return period to 26% at 100 year return period, and from 12.8% to 58.4% for the upper limit for the respective return periods. This methodology can be integrated into policy formulation for the design of stormwater and flood management infrastructures in the Ghaap plateau, where mining is the main economic activity.
Phillips, R.; Samadi, S. Z.; Meadows, M.
2017-12-01
The potential for the intensity of extreme rainfall to increase with climate change nonstationarity has emerged as a prevailing issue for the design of engineering infrastructure, underscoring the need to better characterize the statistical assumptions underlying hydrological frequency analysis. The focus of this study is on developing probabilistic rainfall intensity-duration-frequency (IDF) curves for the major catchments in South Carolina (SC) where the October 02-05, 2015 floods caused infrastructure damages and several lives to be lost. Continuous to discrete probability distributions including Weibull, the generalized extreme value (GEV), the Generalized Pareto (GP), the Gumbel, the Fréchet, the normal, and the log-normal functions were fitted to the short duration (i.e., 24-hr) intense rainfall. Analysis suggests that the GEV probability distribution provided the most adequate fit to rainfall records. Rainfall frequency analysis indicated return periods above 500 years for urban drainage systems with a maximum return level of approximately 2,744 years, whereas rainfall magnitude was much lower in rural catchments. Further, the return levels (i.e., 2, 20, 50,100, 500, and 1000 years) computed by Monte Carlo method were consistently higher than the NOAA design IDF curves. Given the potential increase in the magnitude of intense rainfall, current IDF curves can substantially underestimate the frequency of extremes, indicating the susceptibility of the storm drainage and flood control structures in SC that were designed under assumptions of a stationary climate.
Yan, Hongxiang; Sun, Ning; Wigmosta, Mark; Skaggs, Richard; Hou, Zhangshuan; Leung, Ruby
2018-02-01
There is a renewed focus on the design of infrastructure resilient to extreme hydrometeorological events. While precipitation-based intensity-duration-frequency (IDF) curves are commonly used as part of infrastructure design, a large percentage of peak runoff events in snow-dominated regions are caused by snowmelt, particularly during rain-on-snow (ROS) events. In these regions, precipitation-based IDF curves may lead to substantial overestimation/underestimation of design basis events and subsequent overdesign/underdesign of infrastructure. To overcome this deficiency, we proposed next-generation IDF (NG-IDF) curves, which characterize the actual water reaching the land surface. We compared NG-IDF curves to standard precipitation-based IDF curves for estimates of extreme events at 376 Snowpack Telemetry (SNOTEL) stations across the western United States that each had at least 30 years of high-quality records. We found standard precipitation-based IDF curves at 45% of the stations were subject to underdesign, many with significant underestimation of 100 year extreme events, for which the precipitation-based IDF curves can underestimate water potentially available for runoff by as much as 125% due to snowmelt and ROS events. The regions with the greatest potential for underdesign were in the Pacific Northwest, the Sierra Nevada Mountains, and the Middle and Southern Rockies. We also found the potential for overdesign at 20% of the stations, primarily in the Middle Rockies and Arizona mountains. These results demonstrate the need to consider snow processes in the development of IDF curves, and they suggest use of the more robust NG-IDF curves for hydrologic design in snow-dominated environments.
Energy Technology Data Exchange (ETDEWEB)
Yan, Hongxiang [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington United States; Sun, Ning [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington United States; Wigmosta, Mark [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington United States; Distinguished Faculty Fellow, Department of Civil and Environmental Engineering, University of Washington, Seattle Washington United States; Skaggs, Richard [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington United States; Hou, Zhangshuan [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington United States; Leung, Ruby [Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland Washington United States
2018-02-01
There is a renewed focus on the design of infrastructure resilient to extreme hydrometeorological events. While precipitation-based intensity-duration-frequency (IDF) curves are commonly used as part of infrastructure design, a large percentage of peak runoff events in snow-dominated regions are caused by snowmelt, particularly during rain-on-snow (ROS) events. In these regions, precipitation-based IDF curves may lead to substantial over-/under-estimation of design basis events and subsequent over-/under-design of infrastructure. To overcome this deficiency, we proposed next-generation IDF (NG-IDF) curves, which characterize the actual water reaching the land surface. We compared NG-IDF curves to standard precipitation-based IDF curves for estimates of extreme events at 376 Snowpack Telemetry (SNOTEL) stations across the western United States that each had at least 30 years of high-quality records. We found standard precipitation-based IDF curves at 45% of the stations were subject to under-design, many with significant under-estimation of 100-year extreme events, for which the precipitation-based IDF curves can underestimate water potentially available for runoff by as much as 125% due to snowmelt and ROS events. The regions with the greatest potential for under-design were in the Pacific Northwest, the Sierra Nevada Mountains, and the Middle and Southern Rockies. We also found the potential for over-design at 20% of the stations, primarily in the Middle Rockies and Arizona mountains. These results demonstrate the need to consider snow processes in the development of IDF curves, and they suggest use of the more robust NG-IDF curves for hydrologic design in snow-dominated environments.
Regional flow duration curves for ungauged sites in Sicily
Directory of Open Access Journals (Sweden)
F. Viola
2011-01-01
Full Text Available Flow duration curves are simple and powerful tools to deal with many hydrological and environmental problems related to water quality assessment, water-use assessment and water allocation. Unfortunately the scarcity of streamflow data enables the use of these instruments only for gauged basins. A regional model is developed here for estimating flow duration curves at ungauged basins in Sicily, Italy. Due to the complex ephemeral behavior of the examined region, this study distinguishes dry periods, when flows are zero, from wet periods using a three parameters power law to describe the frequency distribution of flows. A large dataset of streamflows has been analyzed and the parameters of flow duration curves have been derived for about fifty basins. Regional regression equations have been developed to derive flow duration curves starting from morphological basin characteristics.
Ritschel, Christoph; Ulbrich, Uwe; Névir, Peter; Rust, Henning W.
2017-12-01
For several hydrological modelling tasks, precipitation time series with a high (i.e. sub-daily) resolution are indispensable. The data are, however, not always available, and thus model simulations are used to compensate. A canonical class of stochastic models for sub-daily precipitation are Poisson cluster processes, with the original Bartlett-Lewis (OBL) model as a prominent representative. The OBL model has been shown to well reproduce certain characteristics found in observations. Our focus is on intensity-duration-frequency (IDF) relationships, which are of particular interest in risk assessment. Based on a high-resolution precipitation time series (5 min) from Berlin-Dahlem, OBL model parameters are estimated and IDF curves are obtained on the one hand directly from the observations and on the other hand from OBL model simulations. Comparing the resulting IDF curves suggests that the OBL model is able to reproduce the main features of IDF statistics across several durations but cannot capture rare events (here an event with a return period larger than 1000 years on the hourly timescale). In this paper, IDF curves are estimated based on a parametric model for the duration dependence of the scale parameter in the generalized extreme value distribution; this allows us to obtain a consistent set of curves over all durations. We use the OBL model to investigate the validity of this approach based on simulated long time series.
Marra, Francesco; Morin, Efrat
2015-12-01
Intensity-Duration-Frequency (IDF) curves are widely used in flood risk management because they provide an easy link between the characteristics of a rainfall event and the probability of its occurrence. Weather radars provide distributed rainfall estimates with high spatial and temporal resolutions and overcome the scarce representativeness of point-based rainfall for regions characterized by large gradients in rainfall climatology. This work explores the use of radar quantitative precipitation estimation (QPE) for the identification of IDF curves over a region with steep climatic transitions (Israel) using a unique radar data record (23 yr) and combined physical and empirical adjustment of the radar data. IDF relationships were derived by fitting a generalized extreme value distribution to the annual maximum series for durations of 20 min, 1 h and 4 h. Arid, semi-arid and Mediterranean climates were explored using 14 study cases. IDF curves derived from the study rain gauges were compared to those derived from radar and from nearby rain gauges characterized by similar climatology, taking into account the uncertainty linked with the fitting technique. Radar annual maxima and IDF curves were generally overestimated but in 70% of the cases (60% for a 100 yr return period), they lay within the rain gauge IDF confidence intervals. Overestimation tended to increase with return period, and this effect was enhanced in arid climates. This was mainly associated with radar estimation uncertainty, even if other effects, such as rain gauge temporal resolution, cannot be neglected. Climatological classification remained meaningful for the analysis of rainfall extremes and radar was able to discern climatology from rainfall frequency analysis.
DEFF Research Database (Denmark)
Madsen, H.; Arnbjerg-Nielsen, Karsten; Mikkelsen, Peter Steen
2009-01-01
The regional model for estimation of extreme rainfall characteristics in Denmark has been updated with data from the augmented rain database 1 January 1997-1 August 2005, corresponding to almost twice the amount of data used in the previous study (1 January 1979-1 January 1997). In general...... patterns and a sub-regional division of the country in a western and eastern part. Comparison with the previous regional analysis shows a general increase in extreme rainfall characteristics. For the durations (30 min-3 h) and return periods (similar to 10 years) typical for most urban drainage designs...
Kim, Nam Won; Shin, Mun-Ju; Lee, Jeong Eun
2016-04-01
The analysis of storm effects on floods is essential step for designing hydraulic structure and flood plain. There are previous studies for analyzing the relationship between the storm patterns and peak flow, flood volume and durations for various sizes of the catchments, but they are not enough to analyze the natural storm effects on flood responses quantitatively. This study suggests a novel method of quantitative analysis using unique factors extracted from the time series of storms and floods to investigate the relationship between natural storms and their corresponding flood responses. We used a distributed rainfall-runoff model of Grid based Rainfall-runoff Model (GRM) to generate the simulated flow and areal rainfall for 50 catchments in Republic of Korea size from 5.6 km2 to 1584.2 km2, which are including overlapped dependent catchments and non-overlapped independent catchments. The parameters of the GRM model were calibrated to get the good model performances of Nash-Sutcliffe efficiency. Then Flood-Intensity-Duration Curve (FIDC) and Rainfall-Intensity-Duration Curve (RIDC) were generated by Flood-Duration-Frequency and Intensity-Duration-Frequency methods respectively using the time series of hydrographs and hyetographs. Time of concentration developed for the Korea catchments was used as a consistent measure to extract the unique factors from the FIDC and RIDC over the different size of catchments. These unique factors for the storms and floods were analyzed against the different size of catchments to investigate the natural storm effects on floods. This method can be easily used to get the intuition of the natural storm effects with various patterns on flood responses. Acknowledgement This research was supported by a grant (11-TI-C06) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.
Demissie, Y. K.; Mortuza, M. R.; Li, H. Y.
2015-12-01
The observed and anticipated increasing trends in extreme storm magnitude and frequency, as well as the associated flooding risk in the Pacific Northwest highlighted the need for revising and updating the local intensity-duration-frequency (IDF) curves, which are commonly used for designing critical water infrastructure. In Washington State, much of the drainage system installed in the last several decades uses IDF curves that are outdated by as much as half a century, making the system inadequate and vulnerable for flooding as seen more frequently in recent years. In this study, we have developed new and forward looking rainfall and runoff IDF curves for each county in Washington State using recently observed and projected precipitation data. Regional frequency analysis coupled with Bayesian uncertainty quantification and model averaging methods were used to developed and update the rainfall IDF curves, which were then used in watershed and snow models to develop the runoff IDF curves that explicitly account for effects of snow and drainage characteristic into the IDF curves and related designs. The resulted rainfall and runoff IDF curves provide more reliable, forward looking, and spatially resolved characteristics of storm events that can assist local decision makers and engineers to thoroughly review and/or update the current design standards for urban and rural storm water management infrastructure in order to reduce the potential ramifications of increasing severe storms and resulting floods on existing and planned storm drainage and flood management systems in the state.
Ghazavi, Reza; Moafi Rabori, Ali; Ahadnejad Reveshty, Mohsen
2016-01-01
Estimate design storm based on rainfall intensity–duration–frequency (IDF) curves is an important parameter for hydrologic planning of urban areas. The main aim of this study was to estimate rainfall intensities of Zanjan city watershed based on overall relationship of rainfall IDF curves and appropriate model of hourly rainfall estimation (Sherman method, Ghahreman and Abkhezr method). Hydrologic and hydraulic impacts of rainfall IDF curves change in flood properties was evaluated via Stormw...
Development of Sub-Daily Intensity Duration Frequency (IDF) Curves for Major Urban Areas in India
Ali, H.; Mishra, V.
2014-12-01
Extreme precipitation events disrupt urban transportation and cause enormous damage to infrastructure. Urban areas are fast responding catchments due to significant impervious surface. Stormwater designs based on daily rainfall data provide inadequate information. We, therefore, develop intensity-duration-frequency curves using sub-daily (1 hour to 12 hour) rainfall data for 57 major urban areas in India. While rain gage stations data from urban areas are most suitable, but stations are unevenly distributed and their data have gaps and inconsistencies. Therefore, we used hourly rainfall data from the Modern Era Retrospective-analysis for Research and Applications (MERRA), which provides a long term data (1979 onwards). Since reanalysis products have uncertainty associated with them we need to enhance their accuracy before their application. We compared daily rain gage station data obtained from Global Surface Summary of Day Data (GSOD) available for 65 stations for the period of 2000-2010 with gridded daily rainfall data provided by Indian Meteorological Department (IMD). 3-hourly data from NOAA/Climate Prediction Center morphing technique (CMORPH), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), and the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) were aggregated to daily for comparison with GSOD station data . TMPA is found to be best correlated with GSOD data. We used TMPA data to correct MERRA's hourly precipitation, which were applied to develop IDF curves. We compared results with IDF curves from empirical methods and found substantial disparities in the existing stormwater designs in India.
Ghiaei, Farhad; Kankal, Murat; Anilan, Tugce; Yuksek, Omer
2018-01-01
The analysis of rainfall frequency is an important step in hydrology and water resources engineering. However, a lack of measuring stations, short duration of statistical periods, and unreliable outliers are among the most important problems when designing hydrology projects. In this study, regional rainfall analysis based on L-moments was used to overcome these problems in the Eastern Black Sea Basin (EBSB) of Turkey. The L-moments technique was applied at all stages of the regional analysis, including determining homogeneous regions, in addition to fitting and estimating parameters from appropriate distribution functions in each homogeneous region. We studied annual maximum rainfall height values of various durations (5 min to 24 h) from seven rain gauge stations located in the EBSB in Turkey, which have gauging periods of 39 to 70 years. Homogeneity of the region was evaluated by using L-moments. The goodness-of-fit criterion for each distribution was defined as the ZDIST statistics, depending on various distributions, including generalized logistic (GLO), generalized extreme value (GEV), generalized normal (GNO), Pearson type 3 (PE3), and generalized Pareto (GPA). GLO and GEV determined the best distributions for short (5 to 30 min) and long (1 to 24 h) period data, respectively. Based on the distribution functions, the governing equations were extracted for calculation of intensities of 2, 5, 25, 50, 100, 250, and 500 years return periods (T). Subsequently, the T values for different rainfall intensities were estimated using data quantifying maximum amount of rainfall at different times. Using these T values, duration, altitude, latitude, and longitude values were used as independent variables in a regression model of the data. The determination coefficient ( R 2) value indicated that the model yields suitable results for the regional relationship of intensity-duration-frequency (IDF), which is necessary for the design of hydraulic structures in small and
DEFF Research Database (Denmark)
Madsen, H.; Mikkelsen, Peter Steen; Rosbjerg, Dan
2002-01-01
A general framework for regional analysis and modeling of extreme rainfall characteristics is presented. The model is based on the partial duration series (PDS) method that includes in the analysis all events above a threshold level. In the PDS model the average annual number of exceedances...
Estimation of regional intensity-duration-frequency curves for extreme precipitation
DEFF Research Database (Denmark)
Madsen, Henrik; Mikkelsen, Peter Steen; Rosbjerg, Dan
1998-01-01
of regional homogeneity and identification of a proper regional distribution L-moment analysis is applied. To analyse the regional variability in more detail, a generalised least squares regression analysis is carried out that relates the PDS model parameters to climatic and physiographic characteristics...
intensity, duration and frequency of rainstorms in lokoja
African Journals Online (AJOL)
Shuaibu et al.
This study analyzed the Intensity, duration and frequency (IDF) of rainstorms in Lokoja. ... INTRODUCTION. Rainfall worldwide has certain characteristics where it occurs. ..... State University of Science and Technology, Port. Harcourt, Nigeria.
Ziegeweid, Jeffrey R.; Lorenz, David L.; Sanocki, Chris A.; Czuba, Christiana R.
2015-12-24
Knowledge of the magnitude and frequency of low flows in streams, which are flows in a stream during prolonged dry weather, is fundamental for water-supply planning and design; waste-load allocation; reservoir storage design; and maintenance of water quality and quantity for irrigation, recreation, and wildlife conservation. This report presents the results of a statewide study for which regional regression equations were developed for estimating 13 flow-duration curve statistics and 10 low-flow frequency statistics at ungaged stream locations in Minnesota. The 13 flow-duration curve statistics estimated by regression equations include the 0.0001, 0.001, 0.02, 0.05, 0.1, 0.25, 0.50, 0.75, 0.9, 0.95, 0.99, 0.999, and 0.9999 exceedance-probability quantiles. The low-flow frequency statistics include annual and seasonal (spring, summer, fall, winter) 7-day mean low flows, seasonal 30-day mean low flows, and summer 122-day mean low flows for a recurrence interval of 10 years. Estimates of the 13 flow-duration curve statistics and the 10 low-flow frequency statistics are provided for 196 U.S. Geological Survey continuous-record streamgages using streamflow data collected through September 30, 2012.
Hosseinzadehtalaei, Parisa; Tabari, Hossein; Willems, Patrick
2018-02-01
An ensemble of 88 regional climate model (RCM) simulations at 0.11° and 0.44° spatial resolutions from the EURO-CORDEX project is analyzed for central Belgium to investigate the projected impact of climate change on precipitation intensity-duration-frequency (IDF) relationships and extreme precipitation quantiles typically used in water engineering designs. The rate of uncertainty arising from the choice of RCM, driving GCM, and radiative concentration pathway (RCP4.5 & RCP8.5) is quantified using a variance decomposition technique after reconstruction of missing data in GCM × RCM combinations. A comparative analysis between the historical simulations of the EURO-CORDEX 0.11° and 0.44° RCMs shows higher precipitation intensities by the finer resolution runs, leading to a larger overestimation of the observations-based IDFs by the 0.11° runs. The results reveal that making a temporal stationarity assumption for the climate system may lead to underestimation of precipitation quantiles up to 70% by the end of this century. This projected increase is generally larger for the 0.11° RCMs compared with the 0.44° RCMs. The relative changes in extreme precipitation do depend on return period and duration, indicating an amplification for larger return periods and for smaller durations. The variance decomposition approach generally identifies RCM as the most dominant component of uncertainty in changes of more extreme precipitation (return period of 10 years) for both 0.11° and 0.44° resolutions, followed by GCM and RCP scenario. The uncertainties associated with cross-contributions of RCMs, GCMs, and RCPs play a non-negligible role in the associated uncertainties of the changes.
Morin, Efrat; Marra, Francesco; Peleg, Nadav; Mei, Yiwen; Anagnostou, Emmanouil N.
2017-04-01
Rainfall frequency analysis is used to quantify the probability of occurrence of extreme rainfall and is traditionally based on rain gauge records. The limited spatial coverage of rain gauges is insufficient to sample the spatiotemporal variability of extreme rainfall and to provide the areal information required by management and design applications. Conversely, remote sensing instruments, even if quantitative uncertain, offer coverage and spatiotemporal detail that allow overcoming these issues. In recent years, remote sensing datasets began to be used for frequency analyses, taking advantage of increased record lengths and quantitative adjustments of the data. However, the studies so far made use of concepts and techniques developed for rain gauge (i.e. point or multiple-point) data and have been validated by comparison with gauge-derived analyses. These procedures add further sources of uncertainty and prevent from isolating between data and methodological uncertainties and from fully exploiting the available information. In this study, we step out of the gauge-centered concept presenting a direct comparison between at-site Intensity-Duration-Frequency (IDF) curves derived from different remote sensing datasets on corresponding spatial scales, temporal resolutions and records. We analyzed 16 years of homogeneously corrected and gauge-adjusted C-Band weather radar estimates, high-resolution CMORPH and gauge-adjusted high-resolution CMORPH over the Eastern Mediterranean. Results of this study include: (a) good spatial correlation between radar and satellite IDFs ( 0.7 for 2-5 years return period); (b) consistent correlation and dispersion in the raw and gauge adjusted CMORPH; (c) bias is almost uniform with return period for 12-24 h durations; (d) radar identifies thicker tail distributions than CMORPH and the tail of the distributions depends on the spatial and temporal scales. These results demonstrate the potential of remote sensing datasets for rainfall
Dealing with Non-stationarity in Intensity-Frequency-Duration Curve
Rengaraju, S.; Rajendran, V.; C T, D.
2017-12-01
Extremes like flood and drought are becoming frequent and more vulnerable in recent times, generally attributed to the recent revelation of climate change. One of the main concerns is that whether the present infrastructures like dams, storm water drainage networks, etc., which were designed following the so called `stationary' assumption, are capable of withstanding the expected severe extremes. Stationary assumption considers that extremes are not changing with respect to time. However, recent studies proved that climate change has altered the climate extremes both temporally and spatially. Traditionally, the observed non-stationary in the extreme precipitation is incorporated in the extreme value distributions in terms of changing parameters. Nevertheless, this raises a question which parameter needs to be changed, i.e. location or scale or shape, since either one or more of these parameters vary at a given location. Hence, this study aims to detect the changing parameters to reduce the complexity involved in the development of non-stationary IDF curve and to provide the uncertainty bound of estimated return level using Bayesian Differential Evolutionary Monte Carlo (DE-MC) algorithm. Firstly, the extreme precipitation series is extracted using Peak Over Threshold. Then, the time varying parameter(s) is(are) detected for the extracted series using Generalized Additive Models for Location Scale and Shape (GAMLSS). Then, the IDF curve is constructed using Generalized Pareto Distribution incorporating non-stationarity only if the parameter(s) is(are) changing with respect to time, otherwise IDF curve will follow stationary assumption. Finally, the posterior probability intervals of estimated return revel are computed through Bayesian DE-MC approach and the non-stationary based IDF curve is compared with the stationary based IDF curve. The results of this study emphasize that the time varying parameters also change spatially and the IDF curves should incorporate non
Yang, Z.; Burn, D. H.
2017-12-01
Extreme rainfall events can have devastating impacts on society. To quantify the associated risk, the IDF curve has been used to provide the essential rainfall-related information for urban planning. However, the recent changes in the rainfall climatology caused by climate change and urbanization have made the estimates provided by the traditional regional IDF approach increasingly inaccurate. This inaccuracy is mainly caused by two problems: 1) The ineffective choice of similarity indicators for the formation of a homogeneous group at different regions; and 2) An inadequate number of stations in the pooling group that does not adequately reflect the optimal balance between group size and group homogeneity or achieve the lowest uncertainty in the rainfall quantiles estimates. For the first issue, to consider the temporal difference among different meteorological and topographic indicators, a three-layer design is proposed based on three stages in the extreme rainfall formation: cloud formation, rainfall generation and change of rainfall intensity above urban surface. During the process, the impacts from climate change and urbanization are considered through the inclusion of potential relevant features at each layer. Then to consider spatial difference of similarity indicators for the homogeneous group formation at various regions, an automatic feature selection and weighting algorithm, specifically the hybrid searching algorithm of Tabu search, Lagrange Multiplier and Fuzzy C-means Clustering, is used to select the optimal combination of features for the potential optimal homogenous groups formation at a specific region. For the second issue, to compare the uncertainty of rainfall quantile estimates among potential groups, the two sample Kolmogorov-Smirnov test-based sample ranking process is used. During the process, linear programming is used to rank these groups based on the confidence intervals of the quantile estimates. The proposed methodology fills the gap
Jun, Changhyun; Qin, Xiaosheng; Gan, Thian Yew; Tung, Yeou-Koung; De Michele, Carlo
2017-10-01
This study presents a storm-event based bivariate frequency analysis approach to determine design rainfalls in which, the number, intensity and duration of actual rainstorm events were considered. To derive more realistic design storms, the occurrence probability of an individual rainstorm event was determined from the joint distribution of storm intensity and duration through a copula model. Hourly rainfall data were used at three climate stations respectively located in Singapore, South Korea and Canada. It was found that the proposed approach could give a more realistic description of rainfall characteristics of rainstorm events and design rainfalls. As results, the design rainfall quantities from actual rainstorm events at the three studied sites are consistently lower than those obtained from the conventional rainfall depth-duration-frequency (DDF) method, especially for short-duration storms (such as 1-h). It results from occurrence probabilities of each rainstorm event and a different angle for rainfall frequency analysis, and could offer an alternative way of describing extreme rainfall properties and potentially help improve the hydrologic design of stormwater management facilities in urban areas.
Hou, Z.; Ren, H.; Sun, N.; Leung, L. R.; Liu, Y.; Coleman, A. M.; Skaggs, R.; Wigmosta, M. S.
2017-12-01
Hydrologic engineering design usually involves intensity-duration-frequency (IDF) analysis for calculating runoff from a design storm of specified precipitation frequency and duration using event-based hydrologic rainfall-runoff models. Traditionally, the procedure assumes climate stationarity and neglects snowmelt-driven runoff contribution to floods. In this study, we used high resolution climate simulations to provide inputs to the physics-based Distributed Hydrology Soil and Vegetation Model (DHSVM) to determine the spatially distributed precipitation and snowmelt available for runoff. Climate model outputs were extracted around different mountainous field sites in Colorado and California. IDF curves were generated at each numerical grid of DHSVM based on the simulated precipitation, temperature, and available water for runoff. Quantitative evaluation of trending and stationarity tests were conducted to identify (quasi-)stationary time periods for reliable IDF analysis. The impact of stationarity was evaluated by comparing the derived IDF attributes with respect to time windows of different length and level of stationarity. Spatial mapping of event return-period was performed for various design storms, and spatial mapping of event intensity was performed for given duration and return periods. IDF characteristics were systematically compared (historical vs RCP4.5 vs RCP8.5) using annual maximum series vs partial duration series data with the goal of providing reliable IDF analyses to support hydrologic engineering design.
Development and comparison of different intensity duration ...
African Journals Online (AJOL)
Nigerian Journal of Technology ... Microsoft Excel software was used to develop exponential, logarithmic and power intensity-duration-frequency models for return period (T) of duration-frequency models for return period (T) of between 2 years and 100 years using rainfall intensity data for durations of 2, 5, 10, 15, 30, 60, ...
An approach toward incorporation of global warming effects into Intensity-Duration-Frequency values
Kunkel, K.; Easterling, D. R.
2017-12-01
Rising global temperatures from increasing greenhouse gas concentrations will increase overall atmospheric water vapor concentrations. There is a high level of scientific confidence that this will increase the future intensity and frequency of extreme precipitation events, even in regions where overall precipitation may decrease. For control of runoff from extreme rainfall, infrastructure engineering utilizes design values of rainfall known as Intensity-Duration-Frequency (IDF) values. Use of the existing IDF values, which are based solely on historical climate records, is likely to lead to under-design of runoff control structures, and associated increased flood damages. However, future changes in IDF values are uncertain and probably regionally variable. Our paradigm is that changes in IDF values will result from changes in atmospheric capacity (water vapor concentrations) and opportunity (the number and intensity of heavy precipitation-producing storm systems). Relevant storm systems being investigated include extratropical cyclones and their associated fronts, tropical cyclones, and the North American Monsoon system. The overall approach involves developing IDF adjustment factors for changes in these components of the climate system. The adjustment factors have associated uncertainties, primarily from (1) uncertainties in the future pathway of greenhouse gas emissions and (2) variations among climate models in the sensitivity of the climate system to greenhouse gas concentration changes. In addition to meteorological considerations, the lifetime of projects designed using IDF values is an essential consideration because the IDF values may change substantially during that time. The initial results of this project will be discussed.
DEFF Research Database (Denmark)
Madsen, H.; Gregersen, Ida Bülow; Rosbjerg, Dan
2017-01-01
with daily measurements. The Poisson rate is positively correlated to the mean annual precipitation for all durations considered (1 min to 48 hours). The mean intensity can be assumed constant over Denmark for durations up to 1 hour. For durations larger than 1 hour the mean intensity is significantly...... correlated to the mean extreme daily precipitation. A Generalised Pareto distribution with a regional constant shape parameter is adopted. Compared to previous regional studies in Denmark a general increase in extreme rainfall intensity for durations up to 1 hour is found, whereas for larger durations both...
Regionalisation of low flow frequency curves for the Peninsular Malaysia
Mamun, Abdullah A.; Hashim, Alias; Daoud, Jamal I.
2010-02-01
SUMMARYRegional maps and equations for the magnitude and frequency of 1, 7 and 30-day low flows were derived and are presented in this paper. The river gauging stations of neighbouring catchments that produced similar low flow frequency curves were grouped together. As such, the Peninsular Malaysia was divided into seven low flow regions. Regional equations were developed using the multivariate regression technique. An empirical relationship was developed for mean annual minimum flow as a function of catchment area, mean annual rainfall and mean annual evaporation. The regional equations exhibited good coefficient of determination ( R2 > 0.90). Three low flow frequency curves showing the low, mean and high limits for each region were proposed based on a graphical best-fit technique. Knowing the catchment area, mean annual rainfall and evaporation in the region, design low flows of different durations can be easily estimated for the ungauged catchments. This procedure is expected to overcome the problem of data unavailability in estimating low flows in the Peninsular Malaysia.
Obtaining DDF Curves of Extreme Rainfall Data Using Bivariate Copula and Frequency Analysis
DEFF Research Database (Denmark)
Sadri, Sara; Madsen, Henrik; Mikkelsen, Peter Steen
2009-01-01
, situated near Copenhagen in Denmark. For rainfall extracted using method 2, the marginal distribution of depth was found to fit the Generalized Pareto distribution while duration was found to fit the Gamma distribution, using the method of L-moments. The volume was fit with a generalized Pareto...... with duration for a given return period and name them DDF (depth-duration-frequency) curves. The copula approach does not assume the rainfall variables are independent or jointly normally distributed. Rainfall series are extracted in three ways: (1) by maximum mean intensity; (2) by depth and duration...... distribution and the duration was fit with a Pearson type III distribution for rainfall extracted using method 3. The Clayton copula was found to be appropriate for bivariate analysis of rainfall depth and duration for both methods 2 and 3. DDF curves derived using the Clayton copula for depth and duration...
Delgado, Oihane; Campo-Bescós, Miguel A.; López, J. Javier
2017-04-01
Frequently, when we are trying to solve certain hydrological engineering problems, it is often necessary to know rain intensity values related to a specific probability or return period, T. Based on analyses of extreme rainfall events at different time scale aggregation, we can deduce the relationships among Intensity-Duration-Frequency (IDF), that are widely used in hydraulic infrastructure design. However, the lack of long time series of rainfall intensities for smaller time periods, minutes or hours, leads to use mathematical expressions to characterize and extend these curves. One way to deduce them is through the development of synthetic rainfall time series generated from stochastic models, which is evaluated in this work. From recorded accumulated rainfall time series every 10 min in the pluviograph of Igueldo (San Sebastian, Spain) for the time period between 1927-2005, their homogeneity has been checked and possible statistically significant increasing or decreasing trends have also been shown. Subsequently, two models have been calibrated: Bartlett-Lewis and Markov chains models, which are based on the successions of storms, composed for a series of rainfall events, separated by a short interval of time each. Finally, synthetic ten-minute rainfall time series are generated, which allow to estimate detailed IDF curves and compare them with the estimated IDF based on the recorded data.
Uncertainty estimation of Intensity-Duration-Frequency relationships: A regional analysis
Mélèse, Victor; Blanchet, Juliette; Molinié, Gilles
2018-03-01
We propose in this article a regional study of uncertainties in IDF curves derived from point-rainfall maxima. We develop two generalized extreme value models based on the simple scaling assumption, first in the frequentist framework and second in the Bayesian framework. Within the frequentist framework, uncertainties are obtained i) from the Gaussian density stemming from the asymptotic normality theorem of the maximum likelihood and ii) with a bootstrap procedure. Within the Bayesian framework, uncertainties are obtained from the posterior densities. We confront these two frameworks on the same database covering a large region of 100, 000 km2 in southern France with contrasted rainfall regime, in order to be able to draw conclusion that are not specific to the data. The two frameworks are applied to 405 hourly stations with data back to the 1980's, accumulated in the range 3 h-120 h. We show that i) the Bayesian framework is more robust than the frequentist one to the starting point of the estimation procedure, ii) the posterior and the bootstrap densities are able to better adjust uncertainty estimation to the data than the Gaussian density, and iii) the bootstrap density give unreasonable confidence intervals, in particular for return levels associated to large return period. Therefore our recommendation goes towards the use of the Bayesian framework to compute uncertainty.
Directory of Open Access Journals (Sweden)
Wilson Philip M
2010-01-01
Full Text Available Abstract Background It is important to engage in regular physical activity in order to maintain a healthy lifestyle however a large portion of the population is insufficiently active. Understanding how different types of motivation contribute to exercise behavior is an important first step in identifying ways to increase exercise among individuals. The current study employs self-determination theory as a framework from which to examine how motivation contributes to various characteristics of exercise behavior. Methods Regular exercisers (N = 1079; n = 468 males; n = 612 females completed inventories which assessed the frequency, intensity, and duration with which they exercise, as well as the Behavioral Regulation in Exercise Questionnaire including four additional items assessing integrated regulation. Results Bivariate correlations revealed that all three behavioral indices (frequency, intensity, and duration of exercise were more highly correlated with more autonomous than controlling regulations. Regression analyses revealed that integrated and identified regulations predicted exercise frequency for males and females. Integrated regulation was found to be the only predictor of exercise duration across both genders. Finally, introjected regulation predicted exercise intensity for females only. Conclusions These findings suggest that exercise regulations that vary in their degree of internalization can differentially predict characteristics of exercise behavior. Furthermore, in the motivational profile of a regular exerciser, integrated regulation appears to be an important determinant of exercise behavior. These results highlight the importance of assessing integrated regulation in exercise settings where the goal of understanding motivated behavior has important health implications.
Use of Gene Expression Programming in regionalization of flow duration curve
Hashmi, Muhammad Z.; Shamseldin, Asaad Y.
2014-06-01
In this paper, a recently introduced artificial intelligence technique known as Gene Expression Programming (GEP) has been employed to perform symbolic regression for developing a parametric scheme of flow duration curve (FDC) regionalization, to relate selected FDC characteristics to catchment characteristics. Stream flow records of selected catchments located in the Auckland Region of New Zealand were used. FDCs of the selected catchments were normalised by dividing the ordinates by their median value. Input for the symbolic regression analysis using GEP was (a) selected characteristics of normalised FDCs; and (b) 26 catchment characteristics related to climate, morphology, soil properties and land cover properties obtained using the observed data and GIS analysis. Our study showed that application of this artificial intelligence technique expedites the selection of a set of the most relevant independent variables out of a large set, because these are automatically selected through the GEP process. Values of the FDC characteristics obtained from the developed relationships have high correlations with the observed values.
Regional Frequency and Uncertainty Analysis of Extreme Precipitation in Bangladesh
Mortuza, M. R.; Demissie, Y.; Li, H. Y.
2014-12-01
Increased frequency of extreme precipitations, especially those with multiday durations, are responsible for recent urban floods and associated significant losses of lives and infrastructures in Bangladesh. Reliable and routinely updated estimation of the frequency of occurrence of such extreme precipitation events are thus important for developing up-to-date hydraulic structures and stormwater drainage system that can effectively minimize future risk from similar events. In this study, we have updated the intensity-duration-frequency (IDF) curves for Bangladesh using daily precipitation data from 1961 to 2010 and quantified associated uncertainties. Regional frequency analysis based on L-moments is applied on 1-day, 2-day and 5-day annual maximum precipitation series due to its advantages over at-site estimation. The regional frequency approach pools the information from climatologically similar sites to make reliable estimates of quantiles given that the pooling group is homogeneous and of reasonable size. We have used Region of influence (ROI) approach along with homogeneity measure based on L-moments to identify the homogenous pooling groups for each site. Five 3-parameter distributions (i.e., Generalized Logistic, Generalized Extreme value, Generalized Normal, Pearson Type Three, and Generalized Pareto) are used for a thorough selection of appropriate models that fit the sample data. Uncertainties related to the selection of the distributions and historical data are quantified using the Bayesian Model Averaging and Balanced Bootstrap approaches respectively. The results from this study can be used to update the current design and management of hydraulic structures as well as in exploring spatio-temporal variations of extreme precipitation and associated risk.
IDF-curves for precipitation In Belgium
International Nuclear Information System (INIS)
Mohymont, Bernard; Demarde, Gaston R.
2004-01-01
The Intensity-Duration-Frequency (IDF) curves for precipitation constitute a relationship between the intensity, the duration and the frequency of rainfall amounts. The intensity of precipitation is expressed in mm/h, the duration or aggregation time is the length of the interval considered while the frequency stands for the probability of occurrence of the event. IDF-curves constitute a classical and useful tool that is primarily used to dimension hydraulic structures in general, as e.g., sewer systems and which are consequently used to assess the risk of inundation. In this presentation, the IDF relation for precipitation is studied for different locations in Belgium. These locations correspond to two long-term, high-quality precipitation networks of the RMIB: (a) the daily precipitation depths of the climatological network (more than 200 stations, 1951-2001 baseline period); (b) the high-frequency 10-minutes precipitation depths of the hydro meteorological network (more than 30 stations, 15 to 33 years baseline period). For the station of Uccle, an uninterrupted time-series of more than one hundred years of 10-minutes rainfall data is available. The proposed technique for assessing the curves is based on maximum annual values of precipitation. A new analytical formula for the IDF-curves was developed such that these curves stay valid for aggregation times ranging from 10 minutes to 30 days (when fitted with appropriate data). Moreover, all parameters of this formula have physical dimensions. Finally, adequate spatial interpolation techniques are used to provide nationwide extreme values precipitation depths for short- to long-term durations With a given return period. These values are estimated on the grid points of the Belgian ALADIN-domain used in the operational weather forecasts at the RMIB.(Author)
Directory of Open Access Journals (Sweden)
A. Chebbi
2013-10-01
Full Text Available Based on rainfall intensity-duration-frequency (IDF curves, fitted in several locations of a given area, a robust optimization approach is proposed to identify the best locations to install new rain gauges. The advantage of robust optimization is that the resulting design solutions yield networks which behave acceptably under hydrological variability. Robust optimization can overcome the problem of selecting representative rainfall events when building the optimization process. This paper reports an original approach based on Montana IDF model parameters. The latter are assumed to be geostatistical variables, and their spatial interdependence is taken into account through the adoption of cross-variograms in the kriging process. The problem of optimally locating a fixed number of new monitoring stations based on an existing rain gauge network is addressed. The objective function is based on the mean spatial kriging variance and rainfall variogram structure using a variance-reduction method. Hydrological variability was taken into account by considering and implementing several return periods to define the robust objective function. Variance minimization is performed using a simulated annealing algorithm. In addition, knowledge of the time horizon is needed for the computation of the robust objective function. A short- and a long-term horizon were studied, and optimal networks are identified for each. The method developed is applied to north Tunisia (area = 21 000 km2. Data inputs for the variogram analysis were IDF curves provided by the hydrological bureau and available for 14 tipping bucket type rain gauges. The recording period was from 1962 to 2001, depending on the station. The study concerns an imaginary network augmentation based on the network configuration in 1973, which is a very significant year in Tunisia because there was an exceptional regional flood event in March 1973. This network consisted of 13 stations and did not meet World
Continuous rainfall simulation for regional flood risk assessment - application in the Austrian Alps
Salinas, Jose Luis; Nester, Thomas; Komma, Jürgen; Blöschl, Günter
2017-04-01
Generation of realistic synthetic spatial rainfall is of pivotal importance for assessing regional hydroclimatic hazard as the input for long term rainfall-runoff simulations. The correct reproduction of the observed rainfall characteristics, such as regional intensity-duration-frequency curves, is necessary to adequately model the magnitude and frequency of the flood peaks. Furthermore, the replication of the observed rainfall spatial and temporal correlations allows to model important other hydrological features like antecedent soil moisture conditions before extreme rainfall events. In this work, we present an application in the Tirol region (Austrian alps) of a modification of the model presented by Bardossy and Platte (1992), where precipitation is modeled on a station basis as a mutivariate autoregressive model (mAr) in a Normal space, and then transformed to a Gamma-distributed space. For the sake of simplicity, the parameters of the Gamma distributions are assumed to vary monthly according to a sinusoidal function, and are calibrated trying to simultaneously reproduce i) mean annual rainfall, ii) mean daily rainfall amounts, iii) standard deviations of daily rainfall amounts, and iv) 24-hours intensity duration frequency curve. The calibration of the spatial and temporal correlation parameters is performed in a way that the intensity-duration-frequency curves aggregated at different spatial and temporal scales reproduce the measured ones. Bardossy, A., and E. J. Plate (1992), Space-time model for daily rainfall using atmospheric circulation patterns, Water Resour. Res., 28(5), 1247-1259, doi:10.1029/91WR02589.
Giard, M H; Lavikahen, J; Reinikainen, K; Perrin, F; Bertrand, O; Pernier, J; Näätänen, R
1995-01-01
Abstract The present study analyzed the neural correlates of acoustic stimulus representation in echoic sensory memory. The neural traces of auditory sensory memory were indirectly studied by using the mismatch negativity (MMN), an event-related potential component elicited by a change in a repetitive sound. The MMN is assumed to reflect change detection in a comparison process between the sensory input from a deviant stimulus and the neural representation of repetitive stimuli in echoic memory. The scalp topographies of the MMNs elicited by pure tones deviating from standard tones by either frequency, intensity, or duration varied according to the type of stimulus deviance, indicating that the MMNs for different attributes originate, at least in part, from distinct neural populations in the auditory cortex. This result was supported by dipole-model analysis. If the MMN generator process occurs where the stimulus information is stored, these findings strongly suggest that the frequency, intensity, and duration of acoustic stimuli have a separate neural representation in sensory memory.
Spatially-smooth regionalization of flow duration curves in non-pristine basins
Directory of Open Access Journals (Sweden)
D. Ganora
2016-05-01
Full Text Available The flow duration curve (FDC is a fundamental signature of the hydrological cycle to support water management strategies. Despite many studies on this topic, its estimation in ungauged basins is still a relevant issue as the FDC is controlled by different types of processes at different time-space scales, thus resulting quite sensitive to the specific case study. In this work, a regional spatially-smooth procedure to evaluate the annual FDC in ungauged basins is proposed, based on the estimation of the L-moments (mean, L-CV and L-skewness through regression models valid for the whole case study area. In this approach, homogeneous regions are no longer required and the L-moments are allowed to continuously vary along the river network, thus providing a final FDC smoothly evolving for different locations on the river. Regressions are based on a set of topographic, climatic, land use and vegetation descriptors at the basin scale. Moreover, the model ensures that the mean annual runoff is preserved at the river confluences, i.e. the sum of annual flows of the upstream reaches is equal to the predicted annual downstream flow. The proposed model is adapted to incorporate different "sub-models" to account for local information within the regional framework, where man-induced alterations are known, as common in non-pristine catchments. In particular, we propose a module to consider the impact of existing/designed water withdrawals on the L-moments of the FDC. The procedure has been applied to a dataset of daily observation of about 120 gauged basins on the upper Po river basin in North-Western Italy.
Climate change impacts on the duration and frequency of combined sewer overflows
Fortier, C.; Mailhot, A.
2012-12-01
Combined sewer overflows (CSO) occur when large rainwater inflow from heavy precipitation exceeds the capacity of urban combined sewage systems. Many American and European cities with old sewage systems see their water quality significantly deteriorate during such events. In the long term, changes in the rainfall regime due to climate change may lead to more severe and more frequent CSO episodes and thus compel cities to review their global water management. The overall objective of this study is to investigate how climate change will impact CSO frequency and duration. Data from rain gauges located nearby 30 overflow outfalls, in southern Quebec, Canada, were used to identify rain events leading to overflows, using CSO monitored data from May to October during the period 2007-2009. For each site, occurrence and duration of CSO events were recorded and linked to a rainfall event. Many rain events features can be used to predict CSO events, such as total depth, duration, average intensity and peak intensity. Results based on Pearson product-moment correlation coefficients and multiple regression analysis show that CSO occurrence is best predicted by total rainfall. A methodology is proposed to calculate the CSO probability of occurrence and duration for each site of interest using rainfall series as input data. Monte Carlo method is then used to estimate CSO frequency. To evaluate the climate change impact on CSO, these relationships are used with simulated data from the Canadian Regional Climate Model to compare the distribution of annual number of CSO events over the 1960-1990 period and the 2070-2100 period.
Wafa Chouaib; Peter V. Caldwell; Younes Alila
2018-01-01
This paper advances the physical understanding of the flow duration curve (FDC) regional variation. It provides a process-based analysis of the interaction between climate and landscape properties to explain disparities in FDC shapes. We used (i) long term measured flow and precipitation data over 73 catchments from the eastern US. (ii) We calibrated the...
Energy Technology Data Exchange (ETDEWEB)
Wang, Wei; Li, Hong-Yi; Leung, Lai-Yung; Yigzaw, Wondmagegn Y.; Zhao, Jianshi; Lu, Hui; Deng, Zhiqun; Demissie, Yonas; Bloschl, Gunter
2017-10-01
Anthropogenic activities, e.g., reservoir operation, may alter the characteristics of Flood Frequency Curve (FFC) and challenge the basic assumption of stationarity used in flood frequency analysis. This paper presents a combined data-modeling analysis of the nonlinear filtering effects of reservoirs on the FFCs over the contiguous United States. A dimensionless Reservoir Impact Index (RII), defined as the total upstream reservoir storage capacity normalized by the annual streamflow volume, is used to quantify reservoir regulation effects. Analyses are performed for 388 river stations with an average record length of 50 years. The first two moments of the FFC, mean annual maximum flood (MAF) and coefficient of variations (CV), are calculated for the pre- and post-dam periods and compared to elucidate the reservoir regulation effects as a function of RII. It is found that MAF generally decreases with increasing RII but stabilizes when RII exceeds a threshold value, and CV increases with RII until a threshold value beyond which CV decreases with RII. The processes underlying the nonlinear threshold behavior of MAF and CV are investigated using three reservoir models with different levels of complexity. All models capture the non-linear relationships of MAF and CV with RII, suggesting that the basic flood control function of reservoirs is key to the non-linear relationships. The relative roles of reservoir storage capacity, operation objectives, available storage prior to a flood event, and reservoir inflow pattern are systematically investigated. Our findings may help improve flood-risk assessment and mitigation in regulated river systems at the regional scale.
Fouad, Geoffrey; Skupin, André; Hope, Allen
2016-04-01
The flow duration curve (FDC) is one of the most widely used tools to quantify streamflow. Its percentile flows are often required for water resource applications, but these values must be predicted for ungauged basins with insufficient or no streamflow data. Regional regression is a commonly used approach for predicting percentile flows that involves identifying hydrologic regions and calibrating regression models to each region. The independent variables used to describe the physiographic and climatic setting of the basins are a critical component of regional regression, yet few studies have investigated their effect on resulting predictions. In this study, the complexity of the independent variables needed for regional regression is investigated. Different levels of variable complexity are applied for a regional regression consisting of 918 basins in the US. Both the hydrologic regions and regression models are determined according to the different sets of variables, and the accuracy of resulting predictions is assessed. The different sets of variables include (1) a simple set of three variables strongly tied to the FDC (mean annual precipitation, potential evapotranspiration, and baseflow index), (2) a traditional set of variables describing the average physiographic and climatic conditions of the basins, and (3) a more complex set of variables extending the traditional variables to include statistics describing the distribution of physiographic data and temporal components of climatic data. The latter set of variables is not typically used in regional regression, and is evaluated for its potential to predict percentile flows. The simplest set of only three variables performed similarly to the other more complex sets of variables. Traditional variables used to describe climate, topography, and soil offered little more to the predictions, and the experimental set of variables describing the distribution of basin data in more detail did not improve predictions
Rupa, Chandra; Mujumdar, Pradeep
2016-04-01
In urban areas, quantification of extreme precipitation is important in the design of storm water drains and other infrastructure. Intensity Duration Frequency (IDF) relationships are generally used to obtain design return level for a given duration and return period. Due to lack of availability of extreme precipitation data for sufficiently large number of years, estimating the probability of extreme events is difficult. Typically, a single station data is used to obtain the design return levels for various durations and return periods, which are used in the design of urban infrastructure for the entire city. In an urban setting, the spatial variation of precipitation can be high; the precipitation amounts and patterns often vary within short distances of less than 5 km. Therefore it is crucial to study the uncertainties in the spatial variation of return levels for various durations. In this work, the extreme precipitation is modeled spatially using the Bayesian hierarchical analysis and the spatial variation of return levels is studied. The analysis is carried out with Block Maxima approach for defining the extreme precipitation, using Generalized Extreme Value (GEV) distribution for Bangalore city, Karnataka state, India. Daily data for nineteen stations in and around Bangalore city is considered in the study. The analysis is carried out for summer maxima (March - May), monsoon maxima (June - September) and the annual maxima rainfall. In the hierarchical analysis, the statistical model is specified in three layers. The data layer models the block maxima, pooling the extreme precipitation from all the stations. In the process layer, the latent spatial process characterized by geographical and climatological covariates (lat-lon, elevation, mean temperature etc.) which drives the extreme precipitation is modeled and in the prior level, the prior distributions that govern the latent process are modeled. Markov Chain Monte Carlo (MCMC) algorithm (Metropolis Hastings
Aronica, G. T.; Candela, A.
2007-12-01
SummaryIn this paper a Monte Carlo procedure for deriving frequency distributions of peak flows using a semi-distributed stochastic rainfall-runoff model is presented. The rainfall-runoff model here used is very simple one, with a limited number of parameters and practically does not require any calibration, resulting in a robust tool for those catchments which are partially or poorly gauged. The procedure is based on three modules: a stochastic rainfall generator module, a hydrologic loss module and a flood routing module. In the rainfall generator module the rainfall storm, i.e. the maximum rainfall depth for a fixed duration, is assumed to follow the two components extreme value (TCEV) distribution whose parameters have been estimated at regional scale for Sicily. The catchment response has been modelled by using the Soil Conservation Service-Curve Number (SCS-CN) method, in a semi-distributed form, for the transformation of total rainfall to effective rainfall and simple form of IUH for the flood routing. Here, SCS-CN method is implemented in probabilistic form with respect to prior-to-storm conditions, allowing to relax the classical iso-frequency assumption between rainfall and peak flow. The procedure is tested on six practical case studies where synthetic FFC (flood frequency curve) were obtained starting from model variables distributions by simulating 5000 flood events combining 5000 values of total rainfall depth for the storm duration and AMC (antecedent moisture conditions) conditions. The application of this procedure showed how Monte Carlo simulation technique can reproduce the observed flood frequency curves with reasonable accuracy over a wide range of return periods using a simple and parsimonious approach, limited data input and without any calibration of the rainfall-runoff model.
Intensity versus duration of cycling, impact on all-cause and coronary heart disease mortality
DEFF Research Database (Denmark)
Schnohr, Peter; Marott, Jacob L; Jensen, Jan S
2012-01-01
Background: Current recommendations prescribe that every adult should accumulate 30¿minutes or more of moderate physical activity in leisure time, preferably every day of the week. The optimal intensity, duration, and frequency still have to be established. The aim of this study was to examine......: Our findings indicate that the relative intensity, and not the duration of cycling, is of more importance in relation to all-cause and coronary heart disease mortality. Thus our general recommendations to all adults would be that brisk cycling is preferable to slow....
Use of regionalisation approach to develop fire frequency curves for Victoria, Australia
Khastagir, Anirban; Jayasuriya, Niranjali; Bhuyian, Muhammed A.
2017-11-01
It is important to perform fire frequency analysis to obtain fire frequency curves (FFC) based on fire intensity at different parts of Victoria. In this paper fire frequency curves (FFCs) were derived based on forest fire danger index (FFDI). FFDI is a measure related to fire initiation, spreading speed and containment difficulty. The mean temperature (T), relative humidity (RH) and areal extent of open water (LC2) during summer months (Dec-Feb) were identified as the most important parameters for assessing the risk of occurrence of bushfire. Based on these parameters, Andrews' curve equation was applied to 40 selected meteorological stations to identify homogenous stations to form unique clusters. A methodology using peak FFDI from cluster averaged FFDIs was developed by applying Log Pearson Type III (LPIII) distribution to generate FFCs. A total of nine homogeneous clusters across Victoria were identified, and subsequently their FFC's were developed in order to estimate the regionalised fire occurrence characteristics.
Directory of Open Access Journals (Sweden)
S. Ye
2012-11-01
Full Text Available The flow duration curve (FDC is a classical method used to graphically represent the relationship between the frequency and magnitude of streamflow. In this sense it represents a compact signature of temporal runoff variability that can also be used to diagnose catchment rainfall-runoff responses, including similarity and differences between catchments. This paper is aimed at extracting regional patterns of the FDCs from observed daily flow data and elucidating the physical controls underlying these patterns, as a way to aid towards their regionalization and predictions in ungauged basins. The FDCs of total runoff (TFDC using multi-decadal streamflow records for 197 catchments across the continental United States are separated into the FDCs of two runoff components, i.e., fast flow (FFDC and slow flow (SFDC. In order to compactly display these regional patterns, the 3-parameter mixed gamma distribution is employed to characterize the shapes of the normalized FDCs (i.e., TFDC, FFDC and SFDC over the entire data record. This is repeated to also characterize the between-year variability of "annual" FDCs for 8 representative catchments chosen across a climate gradient. Results show that the mixed gamma distribution can adequately capture the shapes of the FDCs and their variation between catchments and also between years. Comparison between the between-catchment and between-year variability of the FDCs revealed significant space-time symmetry. Possible relationships between the parameters of the fitted mixed gamma distribution and catchment climatic and physiographic characteristics are explored in order to decipher and point to the underlying physical controls. The baseflow index (a surrogate for the collective impact of geology, soils, topography and vegetation, as well as climate is found to be the dominant control on the shapes of the normalized TFDC and SFDC, whereas the product of maximum daily precipitation and the fraction of non-rainy days
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Rita de C. F. Damé
2008-06-01
Full Text Available Nos projetos agrícolas de obras hidráulicas, onde não se dispõe de dados observados de vazão, é necessário explorar ao máximo as informações relativas às curvas Intensidade-Duração-Freqüência (IDF. Diante disso, é preciso obter maneira de desenvolver metodologias de estimativas de curvas IDF, em locais que possuam pouco ou nenhum dado pluviográfico. O objetivo do trabalho foi comparar as metodologias de desagregação de precipitações diárias para verificar o ganho de informação em termos de curvas IDF, comparadas àquela obtida a partir de dados observados (histórica. Os métodos utilizados foram: (a Método das Relações (CETESB, 1979; (b BELTRAME et al. (1991; (c ROBAINA & PEITER (1992; (d Modelo Bartlett-Lewis do Pulso Retangular Modificado (DAMÉ, 2001. Utilizou-se de série de dados de precipitação diária de Pelotas - RS, referente ao período de 1982-1998. Para estimar as curvas IDF, a partir dos registros históricos, foram estabelecidas as durações de 15; 30; 60; 360; 720 e 1.440 minutos, e os períodos de retorno de 2; 5 e 10 anos. Os valores de intensidades máximas foram comparados entre si, pelo teste "t" de Student, para os coeficientes linear e angular, e pelo Erro Relativo Médio Quadrático. O método que melhor representou as intensidades máximas de precipitação, nos períodos de retorno de 2 e 10 anos, foi o Método das Relações (CETESB, 1979.Agricultural projects which deal with hydraulic projects and do not possess observed data on outflow need to explore at the most, information about the Intensity-Duration-Frequency (IDF curves. Thus, it is necessary to create ways to develop methodologies that estimate IDF curves for locations that have little or no pluviometric data. The aim of this work was to compare disaggregation methodologies for daily precipitation, to verify the increase in quality information considering the IDF curves, as compared to those originated from observed data
Reliabilty worth: Development of a relationship with outage magnitude, duration and frequency
International Nuclear Information System (INIS)
Turner, F.P.P.; Katrichak, A.M.; Dwyer, A.; Edwards, D.; Ibrahim, A.
1994-01-01
British Columbia Hydro's Worth Project Team was founded to determine values for reliability for reference in evaluation of investment and operating decisions. Work to date has produced key preliminary values for specific outages and concepts for the shape of the relationship between value and these determinates of reliability worth, frequency, magnitude and duration. These values and concepts are described. The values are developed through an iterative, trial and refinement approach. The approach incorporates direct input from customers, common sense and judgement, and micro- and macro-economic concepts. Reliability worth values for reduced or prevented outages are presented for residential, commercial, small industrial and mixed sectors and various outage durations. Reliability worth values were obtained through customer surveys. Limitations of the reliability worth value are numerous and are listed. Study of cost vs magnitude of interruption using microeconomic models has shown that costly system improvements to reduce the possibility of widespread outages may not be justified. The case of exceptionally large area outages (blackouts) is examined. The cost vs frequency relationship was examined in terms of the economic concept of utility or satisfaction. Different loss/frequency characteristics are demonstrated for different customer classes. Customer value for reduced outage duration is expressed in a curve with flatter slope than that for eliminated outages. 2 refs., 6 figs
The impact of attention on judgments of frequency and duration.
Directory of Open Access Journals (Sweden)
Isabell Winkler
Full Text Available Previous studies that examined human judgments of frequency and duration found an asymmetrical relationship: While frequency judgments were quite accurate and independent of stimulus duration, duration judgments were highly dependent upon stimulus frequency. A potential explanation for these findings is that the asymmetry is moderated by the amount of attention directed to the stimuli. In the current experiment, participants' attention was manipulated in two ways: (a intrinsically, by varying the type and arousal potential of the stimuli (names, low-arousal and high-arousal pictures, and (b extrinsically, by varying the physical effort participants expended during the stimulus presentation (by lifting a dumbbell vs. relaxing the arm. Participants processed stimuli with varying presentation frequencies and durations and were subsequently asked to estimate the frequency and duration of each stimulus. Sensitivity to duration increased for pictures in general, especially when processed under physical effort. A large effect of stimulus frequency on duration judgments was obtained for all experimental conditions, but a similar large effect of presentation duration on frequency judgments emerged only in the conditions that could be expected to draw high amounts of attention to the stimuli: when pictures were judged under high physical effort. Almost no difference in the mutual impact of frequency and duration was obtained for low-arousal or high-arousal pictures. The mechanisms underlying the simultaneous processing of frequency and duration are discussed with respect to existing models derived from animal research. Options for the extension of such models to human processing of frequency and duration are suggested.
The impact of attention on judgments of frequency and duration.
Winkler, Isabell; Glauer, Madlen; Betsch, Tilmann; Sedlmeier, Peter
2015-01-01
Previous studies that examined human judgments of frequency and duration found an asymmetrical relationship: While frequency judgments were quite accurate and independent of stimulus duration, duration judgments were highly dependent upon stimulus frequency. A potential explanation for these findings is that the asymmetry is moderated by the amount of attention directed to the stimuli. In the current experiment, participants' attention was manipulated in two ways: (a) intrinsically, by varying the type and arousal potential of the stimuli (names, low-arousal and high-arousal pictures), and (b) extrinsically, by varying the physical effort participants expended during the stimulus presentation (by lifting a dumbbell vs. relaxing the arm). Participants processed stimuli with varying presentation frequencies and durations and were subsequently asked to estimate the frequency and duration of each stimulus. Sensitivity to duration increased for pictures in general, especially when processed under physical effort. A large effect of stimulus frequency on duration judgments was obtained for all experimental conditions, but a similar large effect of presentation duration on frequency judgments emerged only in the conditions that could be expected to draw high amounts of attention to the stimuli: when pictures were judged under high physical effort. Almost no difference in the mutual impact of frequency and duration was obtained for low-arousal or high-arousal pictures. The mechanisms underlying the simultaneous processing of frequency and duration are discussed with respect to existing models derived from animal research. Options for the extension of such models to human processing of frequency and duration are suggested.
Price duration versus trading volume in high-frequency data for selected DAX companies
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Christoph Mitterer
2016-12-01
Full Text Available The properties of the time series of durations between consecutive trades of a particular stock have been studied by many contributors in the literature of financial econometrics. Among them are highly prominent scientists like Engle (2000 and Gourieroux and Jasiak (2001. The importance of this topic, accompanied by the growing availability of (ultra-high-frequency data, has prompted an increase of contributions in recent years. Intensive research based on high-frequency data has several financial motivations. First of all, it is linked with microstructure theory. Secondly, it contributes to the literature on stochastic time deformation. But the most important need for research on the dynamics of trade durations is the necessity to manage liquidity risk. The reason is that durations between the following trades are a widely accepted measures of market liquidity. In addition, their volatility reflects the liquidity risk.
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Pudak Juni Laksana
2015-05-01
Full Text Available Debris flow on the slopes of Mount Merapi area became a serious natural disasters because it has great destructive force and velocity. Rainfall with a certain intensity and duration is one component triggering debris flow. Rainfall has variability of the temporal and spatial characteristics influenced by various factors, such as topography and climate. Dharma (2012 suggested to define the characteristics of the intensity of rainfall using rainfall data with a shorter duration with statistical tests to establish the best empirical IDF formula. This research was using of 30 minutes rainfall data for short duration (<3 hours and a spreadsheet software representing duration and distribution of the rainfall. The most appropriate rainfall intensity formula was done by the empirical IDF formula, i.e. Sherman, Kimijima, Hasper and Mononobe. Rainfall intensity analysis applied Frequency Analysis Software (based on Microsoft Excel. Debris flow occurrence was analyzed using MLIT for method A to establish standard rainfall index. Sherman formula performed the best fit to the IDF characteristics of rainfall in the region of the slopes of Mount Merapi. Rainfall distribution pattern showed high intensity rainfall in the first hour and then decreased in the next hour which means distribution for the duration of 3 hours, 12%, 28%, 25%, 16%, 12%, and 7%, respectively with an interval of 30 minutes. Based on critical line, 5 mm of standard rainfall index was gained in the case of warning (R1 and 28 mm in the case of evacuation (R2.
Directory of Open Access Journals (Sweden)
M. Sivapalan
2012-11-01
Full Text Available The goal of this paper is to explore the process controls underpinning regional patterns of variations of streamflow regime behavior, i.e., the mean seasonal variation of streamflow within the year, across the continental United States. The ultimate motivation is to use the resulting process understanding to generate insights into the physical controls of another signature of streamflow variability, namely the flow duration curve (FDC. The construction of the FDC removes the time dependence of flows. Thus in order to better understand the physical controls in regions that exhibit strong seasonal dependence, the regime curve (RC, which is closely connected to the FDC, is studied in this paper and later linked back to the FDC. To achieve these aims a top-down modeling approach is adopted; we start with a simple two-stage bucket model, which is systematically enhanced through addition of new processes on the basis of model performance assessment in relation to observations, using rainfall-runoff data from 197 United States catchments belonging to the MOPEX dataset. Exploration of dominant processes and the determination of required model complexity are carried out through model-based sensitivity analyses, guided by a performance metric. Results indicated systematic regional trends in dominant processes: snowmelt was a key process control in cold mountainous catchments in the north and north-west, whereas snowmelt and vegetation cover dynamics were key controls in the north-east; seasonal vegetation cover dynamics (phenology and interception were important along the Appalachian mountain range in the east. A simple two-bucket model (with no other additions was found to be adequate in warm humid catchments along the west coast and in the south-east, with both regions exhibiting strong seasonality, whereas much more complex models are needed in the dry south and south-west. Agricultural catchments in the mid-west were found to be difficult to predict
Encoding, storage and judgment of experienced frequency and duration
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Tilmann Betsch
2010-08-01
Full Text Available This paper examines conditions that do or do not lead to accurate judgments of frequency (JOF and judgments of duration (JOD. In three experiments, duration and frequency of visually presented stimuli are varied orthogonally in a within-subjects design. Experiment 1 reveals an asymmetric judgment pattern. JOFs reflected actual presentation frequency quite accurately and were unbiased by exposure duration. Conversely, JODs were almost insensitive to actual exposure duration and were systematically biased by presentation frequency. We show, however, that a tendency towards a symmetric judgment pattern can be obtained by manipulating encoding conditions. Sustaining attention during encoding (Experiment 2 or enhancing richness of the encoded stimuli (Experiment 3 increases judgment sensitivity in JOD and yields biases in both directions (JOF biased by exposure duration, JOD biased by presentation frequency. The implications of these findings for underlying memory mechanisms are discussed.
Estimating daily flow duration curves from monthly streamflow data
CSIR Research Space (South Africa)
Smakhtin, VU
2000-01-01
Full Text Available The paper describes two techniques by which to establish 1-day (1d) flow duration curves at an ungauged site where only a simulated or calculated monthly flow time series is available. Both methods employ the straightforward relationships between...
Incorporating Nonstationarity into IDF Curves across CONUS from Station Records and Implications
Wang, K.; Lettenmaier, D. P.
2017-12-01
Intensity-duration-frequency (IDF) curves are widely used for engineering design of storm-affected structures. Current practice is that IDF-curves are based on observed precipitation extremes fit to a stationary probability distribution (e.g., the extreme value family). However, there is increasing evidence of nonstationarity in station records. We apply the Mann-Kendall trend test to over 1000 stations across the CONUS at a 0.05 significance level, and find that about 30% of stations test have significant nonstationarity for at least one duration (1-, 2-, 3-, 6-, 12-, 24-, and 48-hours). We fit the stations to a GEV distribution with time-varying location and scale parameters using a Bayesian- methodology and compare the fit of stationary versus nonstationary GEV distributions to observed precipitation extremes. Within our fitted nonstationary GEV distributions, we compare distributions with a time-varying location parameter versus distributions with both time-varying location and scale parameters. For distributions with two time-varying parameters, we pay particular attention to instances where location and scale trends have opposing directions. Finally, we use the mathematical framework based on work of Koutsoyiannis to generate IDF curves based on the fitted GEV distributions and discuss the implications that using time-varying parameters may have on simple scaling relationships. We apply the above methods to evaluate how frequency statistics based on a stationary assumption compare to those that incorporate nonstationarity for both short and long term projects. Overall, we find that neglecting nonstationarity can lead to under- or over-estimates (depending on the trend for the given duration and region) of important statistics such as the design storm.
Ignee, Andre; Jedrejczyk, Maciej; Schuessler, Gudrun; Jakubowski, Wieslaw; Dietrich, Christoph F
2010-01-01
Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Videos sequences of 31 consecutive patients for at least 60s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10cm depths, whereas all other parameters showed only satisfying results at 4-6cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Ignee, Andre [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: andre.ignee@gmx.de; Jedrejczyk, Maciej [Department of Diagnostic Imaging, 2nd Division of Medical Faculty, Medical University, Ul. Kondratowicza 8, 03-242 Warsaw (Poland)], E-mail: mjedrzejczyk@interia.pl; Schuessler, Gudrun [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: gudrunschuessler@gmx.de; Jakubowski, Wieslaw [Department of Diagnostic Imaging, 2nd Division of Medical Faculty, Medical University, Ul. Kondratowicza 8, 03-242 Warsaw (Poland)], E-mail: ewajbmd@go2.pl; Dietrich, Christoph F. [Department of Internal Medicine and Diagnostic Imaging, Caritas Hospital, Uhlandstr. 7, 97990 Bad Mergentheim (Germany)], E-mail: christoph.dietrich@ckbm.de
2010-01-15
Introduction: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Patients and methods: Videos sequences of 31 consecutive patients for at least 60 s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. Results: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10 cm depths, whereas all other parameters showed only satisfying results at 4-6 cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. Discussion: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4 cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6 cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.
International Nuclear Information System (INIS)
Ignee, Andre; Jedrejczyk, Maciej; Schuessler, Gudrun; Jakubowski, Wieslaw; Dietrich, Christoph F.
2010-01-01
Introduction: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. Patients and methods: Videos sequences of 31 consecutive patients for at least 60 s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. Results: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10 cm depths, whereas all other parameters showed only satisfying results at 4-6 cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. Discussion: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4 cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6 cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.
LEARNING CURVE IN ENDOSCOPIC TRANSNASAL SELLAR REGION SURGERY
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Ananth G
2016-07-01
Full Text Available BACKGROUND The endoscopic endonasal approach for the sellar region lesions is a novel technique and an effective surgical option. The evidence thus far has been conflicting with reports in favour and against a learning curve. We attempt to determine the learning curve associated with this approach. METHODS Retrospective and prospective data of the patients who were surgically treated for sellar region lesions between the year 2013 and 2016 was collected, 32 patients were operated by the endoscopic endonasal approach at Vydehi Institute of Medical Sciences and Research Centre, Bangalore. Age, sex, presenting symptoms, length of hospital stay, surgical approach, type of dissection, duration of surgery, sellar floor repair, intraoperative and postoperative complications were noted. All the procedures were performed by a single neurosurgeon. RESULTS A total of 32 patients were operated amongst which 21 patients were non-functioning pituitary adenomas, 2 were growth hormone secreting functional adenomas, 1 was an invasive pituitary adenoma, 4 were craniopharyngiomas, 2 were meningiomas, 1 was Rathke’s cleft cyst and 1 was a clival chordoma. Headache was the mode of presentation in 12 patients, 12 patients had visual deficits, 6 patients presented with hormonal disturbances amongst which 4 patients presented with features of panhypopituitarism and 2 with acromegaly. Amongst the 4 patients with panhypopituitarism, 2 also had DI, two patients presented with CSF rhinorrhoea. There was a 100% improvement in the patients who presented with visual symptoms. Gross total resection was achieved in all 4 cases of craniopharyngiomas and 13 cases of pituitary adenomas. Postoperative CSF leak was seen in 4 patients who underwent re-exploration and sellar floor repair, 9 patients had postoperative Diabetes Insipidus (DI which was transient, the incidence of DI reduced towards the end of the study. There was a 25% decrease in the operating time towards the end of
Natural frequencies of the frames having curved member
International Nuclear Information System (INIS)
Tekelioglu, M.; Ozyigit, H.A.; Ridvan, H.
2001-01-01
In-plane and out-of-plane vibrations of a frame having a curved member are studied. Although the analysis is carried out on a frame having a straight and a curve beam, it can be applicable for all the frame type structures. Different end conditions are considered for the system. Rotary inertia and extensional effects are included for the curved member. Finite element method is used as analysis tool. Natural frequencies of the curved beams for different end conditions are calculated first, and then the frequencies of the frames are investigated. The transformation from local coordinates to global coordinates for curved beams needs special attention in the analysis. The results are compared with other methods. (author)
Analytical flow duration curves for summer streamflow in Switzerland
Santos, Ana Clara; Portela, Maria Manuela; Rinaldo, Andrea; Schaefli, Bettina
2018-04-01
This paper proposes a systematic assessment of the performance of an analytical modeling framework for streamflow probability distributions for a set of 25 Swiss catchments. These catchments show a wide range of hydroclimatic regimes, including namely snow-influenced streamflows. The model parameters are calculated from a spatially averaged gridded daily precipitation data set and from observed daily discharge time series, both in a forward estimation mode (direct parameter calculation from observed data) and in an inverse estimation mode (maximum likelihood estimation). The performance of the linear and the nonlinear model versions is assessed in terms of reproducing observed flow duration curves and their natural variability. Overall, the nonlinear model version outperforms the linear model for all regimes, but the linear model shows a notable performance increase with catchment elevation. More importantly, the obtained results demonstrate that the analytical model performs well for summer discharge for all analyzed streamflow regimes, ranging from rainfall-driven regimes with summer low flow to snow and glacier regimes with summer high flow. These results suggest that the model's encoding of discharge-generating events based on stochastic soil moisture dynamics is more flexible than previously thought. As shown in this paper, the presence of snowmelt or ice melt is accommodated by a relative increase in the discharge-generating frequency, a key parameter of the model. Explicit quantification of this frequency increase as a function of mean catchment meteorological conditions is left for future research.
Directory of Open Access Journals (Sweden)
M. Sivapalan
2012-11-01
Full Text Available Predictions of hydrological responses in ungauged catchments can benefit from a classification scheme that can organize and pool together catchments that exhibit a level of hydrologic similarity, especially similarity in some key variable or signature of interest. Since catchments are complex systems with a level of self-organization arising from co-evolution of climate and landscape properties, including vegetation, there is much to be gained from developing a classification system based on a comparative study of a population of catchments across climatic and landscape gradients. The focus of this paper is on climate seasonality and seasonal runoff regime, as characterized by the ensemble mean of within-year variation of climate and runoff. The work on regime behavior is part of an overall study of the physical controls on regional patterns of flow duration curves (FDCs, motivated by the fact that regime behavior leaves a major imprint upon the shape of FDCs, especially the slope of the FDCs. As an exercise in comparative hydrology, the paper seeks to assess the regime behavior of 428 catchments from the MOPEX database simultaneously, classifying and regionalizing them into homogeneous or hydrologically similar groups. A decision tree is developed on the basis of a metric chosen to characterize similarity of regime behavior, using a variant of the Iterative Dichotomiser 3 (ID3 algorithm to form a classification tree and associated catchment classes. In this way, several classes of catchments are distinguished, in which the connection between the five catchments' regime behavior and climate and catchment properties becomes clearer. Only four similarity indices are entered into the algorithm, all of which are obtained from smoothed daily regime curves of climatic variables and runoff. Results demonstrate that climate seasonality plays the most significant role in the classification of US catchments, with rainfall timing and climatic aridity index
Flow-duration-frequency behaviour of British rivers based on annual minima data
Zaidman, Maxine D.; Keller, Virginie; Young, Andrew R.; Cadman, Daniel
2003-06-01
A comparison of different probability distribution models for describing the flow-duration-frequency behaviour of annual minima flow events in British rivers is reported. Twenty-five catchments were included in the study, each having stable and natural flow records of at least 30 years in length. Time series of annual minima D-day average flows were derived for each record using durations ( D) of 1, 7, 30, 60, 90, and 365 days and used to construct low flow frequency curves. In each case the Gringorten plotting position formula was used to determine probabilities (of non-exceedance). Four distribution types—Generalised Extreme Value (GEV), Generalised Logistic (GL), Pearson Type-3 (PE3) and Generalised Pareto (GP)—were used to model the probability distribution function for each site. L-moments were used to parameterise individual models, whilst goodness-of-fit tests were used to assess their match to the sample data. The study showed that where short durations (i.e. 60 days or less) were considered, high storage catchments tended to be best represented by GL and GEV distribution models whilst low storage catchments were best described by PE3 or GEV models. However, these models produced reasonable results only within a limited range (e.g. models for high storage catchments did not produce sensible estimates of return periods where the prescribed flow was less than 10% of the mean flow). For annual minima series derived using long duration flow averages (e.g. more than 90 days), GP and GEV models were generally more applicable. The study suggests that longer duration minima do not conform to the same distribution types as short durations, and that catchment properties can influence the type of distribution selected.
[Duration of work absence attributable to non work-related diseases by health regions in catalonia].
Torá Rocamora, Isabel; Martínez Martínez, José Miguel; Delclos Clanchet, Jordi; Jardí Lliberia, Josefina; Alberti Casas, Constança; Serra Pujadas, Consol; Manzanera López, Rafael; Benavides, Fernando G
2010-01-01
This study analyze the duration of episodes of work absence due to non work-related diseases in Catalonia by health regions, assuming a homogeneous distribution of durations between health regions. A retrospective cohort study of 811.790 episodes in 2005 and followed to episode closure through July 2007 provided by the Institut Català d'Avaluacions Mèdiques, describing their median duration (MD) in days for each of the seven health regions of Catalonia. The probability of returning to work was plotted according to Wang_Chang survival curves and median durations were then compared using the Barcelona health region as the referent group. Results were extended through stratification by sex. The Camp de Tarragona health region had the shortest MD (5 days), while the episodes in the Alt Pirineu i Aran region had the longest (MD, 13 days). The Barcelona health region had a MD of 7 days as was the case for Cataluña Central. MD in Girona was 8 days, and in Lleida and Terres de l'Ebre it was 9 days. This latter region also had the highest median duration 13 days. The are significant differences in the duration of work absence between the health regions of Catalonia. These differences persisted after adjusting for age, management of episodes and social security system status, in both men and women.
Historical and future drought in Bangladesh using copula-based bivariate regional frequency analysis
Mortuza, Md Rubayet; Moges, Edom; Demissie, Yonas; Li, Hong-Yi
2018-02-01
The study aims at regional and probabilistic evaluation of bivariate drought characteristics to assess both the past and future drought duration and severity in Bangladesh. The procedures involve applying (1) standardized precipitation index to identify drought duration and severity, (2) regional frequency analysis to determine the appropriate marginal distributions for both duration and severity, (3) copula model to estimate the joint probability distribution of drought duration and severity, and (4) precipitation projections from multiple climate models to assess future drought trends. Since drought duration and severity in Bangladesh are often strongly correlated and do not follow same marginal distributions, the joint and conditional return periods of droughts are characterized using the copula-based joint distribution. The country is divided into three homogeneous regions using Fuzzy clustering and multivariate discordancy and homogeneity measures. For given severity and duration values, the joint return periods for a drought to exceed both values are on average 45% larger, while to exceed either value are 40% less than the return periods from the univariate frequency analysis, which treats drought duration and severity independently. These suggest that compared to the bivariate drought frequency analysis, the standard univariate frequency analysis under/overestimate the frequency and severity of droughts depending on how their duration and severity are related. Overall, more frequent and severe droughts are observed in the west side of the country. Future drought trend based on four climate models and two scenarios showed the possibility of less frequent drought in the future (2020-2100) than in the past (1961-2010).
Directory of Open Access Journals (Sweden)
Luca Falsiroli Maistrello
2018-04-01
Full Text Available BackgroundA variety of interventions has been proposed for symptomatology relief in primary headaches. Among these, manual trigger points (TrPs treatment gains popularity, but its effects have not been investigated yet.ObjectiveThe aim was to establish the effectiveness of manual TrP compared to minimal active or no active interventions in terms of frequency, intensity, and duration of attacks in adult people with primary headaches.MethodsWe searched MEDLINE, COCHRANE, Web Of Science, and PEDro databases up to November 2017 for randomized controlled trials (RCTs. Two independent reviewers appraised the risk-of-bias (RoB and the grading of recommendations, assessment, development, and evaluation (GRADE to evaluate the overall quality of evidence.ResultsSeven RCTs that compared manual treatment vs minimal active intervention were included: 5 focused on tension-type headache (TTH and 2 on Migraine (MH; 3 out of 7 RCTs had high RoB. Combined TTH and MH results show statistically significant reduction for all outcomes after treatment compared to controls, but the level of evidence was very low. Subgroup analysis showed a statistically significant reduction in attack frequency (no. of attacks per month after treatment in TTH (MD −3.50; 95% CI from −4.91 to −2.09; 4 RCTs and in MH (MD −1.92; 95% CI from −3.03 to −0.80; 2 RCTs. Pain intensity (0–100 scale was reduced in TTH (MD −12.83; 95% CI from −19.49 to −6.17; 4 RCTs and in MH (MD −13.60; 95% CI from −19.54 to −7.66; 2RCTs. Duration of attacks (hours was reduced in TTH (MD −0.51; 95% CI from −0.97 to −0.04; 2 RCTs and in MH (MD −10.68; 95% CI from −14.41 to −6.95; 1 RCT.ConclusionManual TrPs treatment of head and neck muscles may reduce frequency, intensity, and duration of attacks in TTH and MH, but the quality of evidence according to GRADE approach was very low for the presence of few studies, high RoB, and imprecision of results.
Low frequency oscillatory flow in a rotating curved pipe
Institute of Scientific and Technical Information of China (English)
陈华军; 章本照; 苏霄燕
2003-01-01
The low frequency oscillatory flow in a rotating curved pipe was studied by using the method of bi-parameter perturbation. Perturbation solutions up to the second order were obtained and the effects of rotationon the low frequency oscillatory flow were examined in detail, The results indicated that there exists evident difference between the low frequency oscillatory flow in a rotating curved pipe and in a curved pipe without ro-tation. During a period, four secondary vortexes may exist on the circular cross-section and the distribution of axial velocity and wall shear stress are related to the ratio of the Coriolis foree to centrifugal foree and the axial pressure gradient.
Low frequency oscillatory flow in a rotating curved pipe
Institute of Scientific and Technical Information of China (English)
陈华军; 章本照; 苏霄燕
2003-01-01
The low frequency oscillatory flow in a rotating curved pipe was studied by using the method of bi-parameter perturbation. Perturbation solutions up to the second order were obtained and the effects of rotation on the low frequency oscillatory flow were examined in detail. The results indicated that there exists evident difference between the low frequency oscillatory flow in a rotating curved pipe and in a curved pipe without rotation. During a period, four secondary vortexes may exist on the circular cross-section and the distribution of axial velocity and wall shear stress are related to the ratio of the Coriolis force to centrifugal force and the axial pressure gradient.
Wind Turbine Power Curves Incorporating Turbulence Intensity
DEFF Research Database (Denmark)
Sørensen, Emil Hedevang Lohse
2014-01-01
. The model and method are parsimonious in the sense that only a single function (the zero-turbulence power curve) and a single auxiliary parameter (the equivalent turbulence factor) are needed to predict the mean power at any desired turbulence intensity. The method requires only ten minute statistics......The performance of a wind turbine in terms of power production (the power curve) is important to the wind energy industry. The current IEC-61400-12-1 standard for power curve evaluation recognizes only the mean wind speed at hub height and the air density as relevant to the power production...
Watson, Kara M.; McHugh, Amy R.
2014-01-01
Regional regression equations were developed for estimating monthly flow-duration and monthly low-flow frequency statistics for ungaged streams in Coastal Plain and non-coastal regions of New Jersey for baseline and current land- and water-use conditions. The equations were developed to estimate 87 different streamflow statistics, which include the monthly 99-, 90-, 85-, 75-, 50-, and 25-percentile flow-durations of the minimum 1-day daily flow; the August–September 99-, 90-, and 75-percentile minimum 1-day daily flow; and the monthly 7-day, 10-year (M7D10Y) low-flow frequency. These 87 streamflow statistics were computed for 41 continuous-record streamflow-gaging stations (streamgages) with 20 or more years of record and 167 low-flow partial-record stations in New Jersey with 10 or more streamflow measurements. The regression analyses used to develop equations to estimate selected streamflow statistics were performed by testing the relation between flow-duration statistics and low-flow frequency statistics for 32 basin characteristics (physical characteristics, land use, surficial geology, and climate) at the 41 streamgages and 167 low-flow partial-record stations. The regression analyses determined drainage area, soil permeability, average April precipitation, average June precipitation, and percent storage (water bodies and wetlands) were the significant explanatory variables for estimating the selected flow-duration and low-flow frequency statistics. Streamflow estimates were computed for two land- and water-use conditions in New Jersey—land- and water-use during the baseline period of record (defined as the years a streamgage had little to no change in development and water use) and current land- and water-use conditions (1989–2008)—for each selected station using data collected through water year 2008. The baseline period of record is representative of a period when the basin was unaffected by change in development. The current period is
Chouaib, Wafa; Caldwell, Peter V.; Alila, Younes
2018-04-01
This paper advances the physical understanding of the flow duration curve (FDC) regional variation. It provides a process-based analysis of the interaction between climate and landscape properties to explain disparities in FDC shapes. We used (i) long term measured flow and precipitation data over 73 catchments from the eastern US. (ii) We calibrated the Sacramento model (SAC-SMA) to simulate soil moisture and flow components FDCs. The catchments classification based on storm characteristics pointed to the effect of catchments landscape properties on the precipitation variability and consequently on the FDC shapes. The landscape properties effect was pronounce such that low value of the slope of FDC (SFDC)-hinting at limited flow variability-were present in regions of high precipitation variability. Whereas, in regions with low precipitation variability the SFDCs were of larger values. The topographic index distribution, at the catchment scale, indicated that saturation excess overland flow mitigated the flow variability under conditions of low elevations with large soil moisture storage capacity and high infiltration rates. The SFDCs increased due to the predominant subsurface stormflow in catchments at high elevations with limited soil moisture storage capacity and low infiltration rates. Our analyses also highlighted the major role of soil infiltration rates on the FDC despite the impact of the predominant runoff generation mechanism and catchment elevation. In conditions of slow infiltration rates in soils of large moisture storage capacity (at low elevations) and predominant saturation excess, the SFDCs were of larger values. On the other hand, the SFDCs decreased in catchments of prevalent subsurface stormflow and poorly drained soils of small soil moisture storage capacity. The analysis of the flow components FDCs demonstrated that the interflow contribution to the response was the higher in catchments with large value of slope of the FDC. The surface flow
Analysis of Rainfall Intensity in Madiun Watershed, East Java
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Muttaqin Muttaqin
2004-01-01
Full Text Available The aim of the reasearch in the area of Madiun River Basin is to make and to analyze the Intensity Duration Curve (IDC i.e. the curve describing graphically the relation between rainfall intensity and rainfall duration in a certain frequent period. Formulation used in the research was Talbot Formula and Ishiguro’s. In the drafting of Intensity Duration Curve it was used specific coefficient i.e by using the rainfall data of fifteen and sixty duration for both applied formulations. The IDC recorded has not mean difference because in both formulation was used coefficient of the same value. The pattern of the rainfall intensity occured directed toward Nort East. It was happened because of the moving clouds directed toward that course. Depression occured at the backward of Mount Lawu, exactly toward East.
Frequency of candidemias in a tertiary care intensive care unit
International Nuclear Information System (INIS)
Yaqub, K.M.; Usman, J.; Zaidi, S.B.H.; Khalil, A.; Noor, N.; Gill, M.M.
2013-01-01
Objective: To determine the frequency of fungal infections in intensive care unit (ICU) of Military Hospital, Rawalpindi, a tertiary care health facility. Study Design: Cross sectional study. Place and Duration of Study: Intensive Care Department of Military Hospital Rawalpindi from 01 Jan 2012 to 30 Jun 2012. Methodology: A total of 89 patients were screened with stay of more than 5 days in intensive care unit. Thirty cases were enrolled in the study for investigation of fungal infections that had fever even after 05 days of being on broad spectrum antibiotics. Culture was done on blood, urine and catheter tip samples as per clinical condition of a patient. Results: Candida infection was found in 23.4% of study cases. The mean age of study patients was 41.2 +- 20.0 years while 63.4% were female patients as compared to 36.7% males. Conclusion: Fungal infections especially candidemias are quite frequent in the intensive care units. (author)
Borucki, Ewa; Berg, Bruce G
2017-05-01
This study investigated the psychophysical effects of distortion products in a listening task traditionally used to estimate the bandwidth of phase sensitivity. For a 2000 Hz carrier, estimates of modulation depth necessary to discriminate amplitude modulated (AM) tones and quasi-frequency modulated (QFM) were measured in a two interval forced choice task as a function modulation frequency. Temporal modulation transfer functions were often non-monotonic at modulation frequencies above 300 Hz. This was likely to be due to a spectral cue arising from the interaction of auditory distortion products and the lower sideband of the stimulus complex. When the stimulus duration was decreased from 200 ms to 20 ms, thresholds for low-frequency modulators rose to near-chance levels, whereas thresholds in the region of non-monotonicities were less affected. The decrease in stimulus duration appears to hinder the listener's ability to use temporal cues in order to discriminate between AM and QFM, whereas spectral information derived from distortion product cues appears more resilient. Copyright © 2017. Published by Elsevier B.V.
Investigation into increasing short-duration rainfall intensities in ...
African Journals Online (AJOL)
2015-04-03
Apr 3, 2015 ... This study explores this expectation by using historical short-duration ... weather station 5-min rainfall data were combined to extend the effective ... evidence was found of trends or indications of changes in rainfall intensities.
Unthank, Michael D.; Newson, Jeremy K.; Williamson, Tanja N.; Nelson, Hugh L.
2012-01-01
Flow- and load-duration curves were constructed from the model outputs of the U.S. Geological Survey's Water Availability Tool for Environmental Resources (WATER) application for streams in Kentucky. The WATER application was designed to access multiple geospatial datasets to generate more than 60 years of statistically based streamflow data for Kentucky. The WATER application enables a user to graphically select a site on a stream and generate an estimated hydrograph and flow-duration curve for the watershed upstream of that point. The flow-duration curves are constructed by calculating the exceedance probability of the modeled daily streamflows. User-defined water-quality criteria and (or) sampling results can be loaded into the WATER application to construct load-duration curves that are based on the modeled streamflow results. Estimates of flow and streamflow statistics were derived from TOPographically Based Hydrological MODEL (TOPMODEL) simulations in the WATER application. A modified TOPMODEL code, SDP-TOPMODEL (Sinkhole Drainage Process-TOPMODEL) was used to simulate daily mean discharges over the period of record for 5 karst and 5 non-karst watersheds in Kentucky in order to verify the calibrated model. A statistical evaluation of the model's verification simulations show that calibration criteria, established by previous WATER application reports, were met thus insuring the model's ability to provide acceptably accurate estimates of discharge at gaged and ungaged sites throughout Kentucky. Flow-duration curves are constructed in the WATER application by calculating the exceedence probability of the modeled daily flow values. The flow-duration intervals are expressed as a percentage, with zero corresponding to the highest stream discharge in the streamflow record. Load-duration curves are constructed by applying the loading equation (Load = Flow*Water-quality criterion) at each flow interval.
Calibration of hydrological models using flow-duration curves
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I. K. Westerberg
2011-07-01
Full Text Available The degree of belief we have in predictions from hydrologic models will normally depend on how well they can reproduce observations. Calibrations with traditional performance measures, such as the Nash-Sutcliffe model efficiency, are challenged by problems including: (1 uncertain discharge data, (2 variable sensitivity of different performance measures to different flow magnitudes, (3 influence of unknown input/output errors and (4 inability to evaluate model performance when observation time periods for discharge and model input data do not overlap. This paper explores a calibration method using flow-duration curves (FDCs to address these problems. The method focuses on reproducing the observed discharge frequency distribution rather than the exact hydrograph. It consists of applying limits of acceptability for selected evaluation points (EPs on the observed uncertain FDC in the extended GLUE approach. Two ways of selecting the EPs were tested – based on equal intervals of discharge and of volume of water. The method was tested and compared to a calibration using the traditional model efficiency for the daily four-parameter WASMOD model in the Paso La Ceiba catchment in Honduras and for Dynamic TOPMODEL evaluated at an hourly time scale for the Brue catchment in Great Britain. The volume method of selecting EPs gave the best results in both catchments with better calibrated slow flow, recession and evaporation than the other criteria. Observed and simulated time series of uncertain discharges agreed better for this method both in calibration and prediction in both catchments. An advantage with the method is that the rejection criterion is based on an estimation of the uncertainty in discharge data and that the EPs of the FDC can be chosen to reflect the aims of the modelling application, e.g. using more/less EPs at high/low flows. While the method appears less sensitive to epistemic input/output errors than previous use of limits of
Gabauer, Douglas J; Li, Xiaolong
2015-04-01
The purpose of this study was to investigate motorcycle-to-barrier crash frequency on horizontally curved roadway sections in Washington State using police-reported crash data linked with roadway data and augmented with barrier presence information. Data included 4915 horizontal curved roadway sections with 252 of these sections experiencing 329 motorcycle-to-barrier crashes between 2002 and 2011. Negative binomial regression was used to predict motorcycle-to-barrier crash frequency using horizontal curvature and other roadway characteristics. Based on the model results, the strongest predictor of crash frequency was found to be curve radius. This supports a motorcycle-to-barrier crash countermeasure placement criterion based, at the very least, on horizontal curve radius. With respect to the existing horizontal curve criterion of 820 feet or less, curves meeting this criterion were found to increase motorcycle-to-barrier crash frequency rate by a factor of 10 compared to curves not meeting this criterion. Other statistically significant predictors were curve length, traffic volume and the location of adjacent curves. Assuming curves of identical radius, the model results suggest that longer curves, those with higher traffic volume, and those that have no adjacent curved sections within 300 feet of either curve end would likely be better candidates for a motorcycle-to-barrier crash countermeasure. Copyright © 2015 Elsevier Ltd. All rights reserved.
Peculiarities of frequency dependence of type 3 solar radio bursts duration
International Nuclear Information System (INIS)
Tsybko, Ya.G.
1989-01-01
From the averaged data of type 3 bursts at the fixed frequencies in the range 12.5-25 MHz and out of this limit it is concluded that there exist two branges of the burst duration dependence on the frequency. This splitting allows to distinguish bursts occurring at the fundamental and the second harmonics of the plasma frequency decreasing with height in the solar corona. The type 3b radiation is characterized by a separate diagram of the mean duration versus frequency of the stria-bursts at the fundamental harmonic
Curved-straight neutron guide system with uniform spatial intensity distribution
International Nuclear Information System (INIS)
Mildner, D.F.R.; Cook, J.C.
2008-01-01
The spatial intensity distribution of neutrons emerging from a curved guide is asymmetric, and straight guide sections are sometimes appended to curved guides to make the intensity distribution more nearly uniform. For idealized uniform illumination and in the perfect reflectivity approximation, the spatial-angular acceptance at the exit of the combination can be made exactly uniform for a range of long wavelengths by using a sufficiently long straight section, together with a curved guide whose outer wall coating has a critical angle slightly greater than those of the other guide walls. We refer to this as a 'phase space tailoring guide' where the coatings on the inner wall and straight section are used to define the required divergence at the end of the guide. Increasing the critical angle of the outer wall of the curved section reduces the characteristic wavelength of the curved guide as well as the wavelength at which ideal uniformity can be obtained. The outer wall coating need only be of sufficiently high critical angle to fill the transmittable phase space area of the straight guide uniformly to adequately short wavelength
Poncelet, L C; Coppens, A G; Meuris, S I; Deltenre, P F
2000-11-01
To evaluate auditory maturation in puppies. Ten clinically normal Beagle puppies. Puppies were examined repeatedly from days 11 to 36 after birth (8 measurements). Click-evoked brain stem auditory-evoked potentials (BAEP) were obtained in response to rarefaction and condensation click stimuli from 90 dB normal hearing level to wave V threshold, using steps of 10 dB. Responses were added, providing an equivalent to alternate polarity clicks, and subtracted, providing the rarefaction-condensation differential potential (RCDP). Steps of 5 dB were used to determine thresholds of RCDP and wave V. Slope of the low-intensity segment of the wave V latency-intensity curve was calculated. The intensity range at which RCDP could not be recorded (ie, pre-RCDP range) was calculated by subtracting the threshold of wave V from threshold of RCDP RESULTS: Slope of the wave V latency-intensity curve low-intensity segment evolved with age, changing from (mean +/- SD) -90.8 +/- 41.6 to -27.8 +/- 4.1 micros/dB. Similar results were obtained from days 23 through 36. The pre-RCDP range diminished as puppies became older, decreasing from 40.0 +/- 7.5 to 20.5 +/- 6.4 dB. Changes in slope of the latency-intensity curve with age suggest enlargement of the audible range of frequencies toward high frequencies up to the third week after birth. Decrease in the pre-RCDP range may indicate an increase of the audible range of frequencies toward low frequencies. Age-related reference values will assist clinicians in detecting hearing loss in puppies.
The use of historical information for regional frequency analysis of extreme skew surge
Frau, Roberto; Andreewsky, Marc; Bernardara, Pietro
2018-03-01
The design of effective coastal protections requires an adequate estimation of the annual occurrence probability of rare events associated with a return period up to 103 years. Regional frequency analysis (RFA) has been proven to be an applicable way to estimate extreme events by sorting regional data into large and spatially distributed datasets. Nowadays, historical data are available to provide new insight on past event estimation. The utilisation of historical information would increase the precision and the reliability of regional extreme's quantile estimation. However, historical data are from significant extreme events that are not recorded by tide gauge. They usually look like isolated data and they are different from continuous data from systematic measurements of tide gauges. This makes the definition of the duration of our observations period complicated. However, the duration of the observation period is crucial for the frequency estimation of extreme occurrences. For this reason, we introduced here the concept of credible duration. The proposed RFA method (hereinafter referenced as FAB, from the name of the authors) allows the use of historical data together with systematic data, which is a result of the use of the credible duration concept.
Atlas of depth-duration frequency of precipitation annual maxima for Texas
Asquith, William H.; Roussel, Meghan C.
2004-01-01
The objective of this Texas Department of Transportation (TxDOT) and U.S. Geological Survey (USGS) cooperatively funded project was to develop a simple-to-use atlas of precipitation depths in Texas for selected storm durations and frequencies on the basis of the research results and unpublished digital archives of Asquith (1998). The selected storm durations are 15 and 30 minutes; 1, 2, 3, 6, and 12 hours; and 1, 2, 3, 5, and 7 days. The selected storm frequencies or annual recurrence intervals are 2, 5, 10, 25, 50, 100, 250, and 500 years. Depth-duration frequency (DDF) of annual precipitation maxima is important for cost-effective, risk-mitigated hydrologic design. DDF values are in common and wide-spread use by public and private entities throughout Texas.
International Nuclear Information System (INIS)
Thatcher, Marcus J.
2007-01-01
In this paper, we describe a method for constructing regional electricity demand data sets at 30 min intervals, which are consistent with climate change scenarios. Specifically, we modify a commonly used linear regression model between regional electricity demand and climate to also describe intraday variability in demand so that regional load duration curves (LDCs) can be predicted. The model is evaluated for four different Australian states that are participants in the Australian National Electricity Market (NEM) and the resultant data sets are found to reproduce each state's LDCs with reasonable accuracy. We also apply the demand model to CSIRO's Mk 3 global climate model data sets that have been downscaled to 60 km resolution using CSIRO's conformal-cubic atmospheric model to estimate how LDCs change as a consequence of a 1 C increase in the average temperature of Australian state capital cities. These regional electricity demand data sets are then useful for economic modelling of electricity markets such as the NEM. (author)
Duration estimates within a modality are integrated sub-optimally
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Ming Bo eCai
2015-08-01
Full Text Available Perceived duration can be influenced by various properties of sensory stimuli. For example, visual stimuli of higher temporal frequency are perceived to last longer than those of lower temporal frequency. How does the brain form a representation of duration when each of two simultaneously presented stimuli influences perceived duration in different way? To answer this question, we investigated the perceived duration of a pair of dynamic visual stimuli of different temporal frequencies in comparison to that of a single visual stimulus of either low or high temporal frequency. We found that the duration representation of simultaneously occurring visual stimuli is best described by weighting the estimates of duration based on each individual stimulus. However, the weighting performance deviates from the prediction of statistically optimal integration. In addition, we provided a Bayesian account to explain a difference in the apparent sensitivity of the psychometric curves introduced by the order in which the two stimuli are displayed in a two-alternative forced-choice task.
Progress toward a microsecond duration, repetitively pulsed, intense- ion beam
International Nuclear Information System (INIS)
Davis, H.A.; Olson, J.C.; Reass, W.A.; Coates, D.M.; Hunt, J.W.; Schleinitz, H.M.; Greenly, J.B.
1996-01-01
A number of intense ion beams applications are emerging requiring repetitive high-average-power beams. These applications include ablative deposition of thin films, rapid melt and resolidification for surface property enhancement, advanced diagnostic neutral beams for the next generation of Tokamaks, and intense pulsed-neutron sources. We are developing a 200-250 keV, 15 kA, 1 μs duration, 1-30 Hz intense ion beam accelerator to address these applications
Directory of Open Access Journals (Sweden)
Ana Letícia Pilz de Castro
2011-08-01
Full Text Available Para a elaboração de projetos na área de drenagem urbana, o conhecimento adequado das precipitações máximas, que são normalmente determinadas a partir de relações Intensidade-Duração-Frequência, é muito importante. O presente trabalho apresenta um estudo para a obtenção da equação IDF para o município de Cuiabá, capital do Estado de Mato Grosso. Os dados utilizados no trabalho foram registrados por estação climatológica localizada em Várzea Grande (MT, com série histórica de 25 anos.AbstractIn order to develop projects in the urban drainage area, it is very important to be aware of adequate maximum rainfall, which is usually determined from relations among Intensity-Duration-Frequency. This paper presents a study to obtain the IDF equation for the Cuiaba city located in Mato Grosso State. The data used in the study were recorded by climatological station, located in Varzea Grande (MT with historical series during 25 years.
International Nuclear Information System (INIS)
Yu, Shiwei; Zhang, Junjie; Zheng, Shuhong; Sun, Han
2015-01-01
This study aims to estimate carbon intensity abatement potential in China at the regional level by proposing a particle swarm optimization–genetic algorithm (PSO–GA) multivariate environmental learning curve estimation method. The model uses two independent variables, namely, per capita gross domestic product (GDP) and the proportion of the tertiary industry in GDP, to construct carbon intensity learning curves (CILCs), i.e., CO 2 emissions per unit of GDP, of 30 provinces in China. Instead of the traditional ordinary least squares (OLS) method, a PSO–GA intelligent optimization algorithm is used to optimize the coefficients of a learning curve. The carbon intensity abatement potentials of the 30 Chinese provinces are estimated via PSO–GA under the business-as-usual scenario. The estimation reveals the following results. (1) For most provinces, the abatement potentials from improving a unit of the proportion of the tertiary industry in GDP are higher than the potentials from raising a unit of per capita GDP. (2) The average potential of the 30 provinces in 2020 will be 37.6% based on the emission's level of 2005. The potentials of Jiangsu, Tianjin, Shandong, Beijing, and Heilongjiang are over 60%. Ningxia is the only province without intensity abatement potential. (3) The total carbon intensity in China weighted by the GDP shares of the 30 provinces will decline by 39.4% in 2020 compared with that in 2005. This intensity cannot achieve the 40%–45% carbon intensity reduction target set by the Chinese government. Additional mitigation policies should be developed to uncover the potentials of Ningxia and Inner Mongolia. In addition, the simulation accuracy of the CILCs optimized by PSO–GA is higher than that of the CILCs optimized by the traditional OLS method. - Highlights: • A PSO–GA-optimized multi-factor environmental learning curve method is proposed. • The carbon intensity abatement potentials of the 30 Chinese provinces are estimated by
International Nuclear Information System (INIS)
Borcherdt, R.D.; Gibbs, J.F.
1976-01-01
Measurements of ground motion generated by nuclear explosions in Nevada have been completed for 99 locations in the San Francisco Bay region, California. The recordings show marked amplitude variations in the frequency band 0.25 to 3.0 Hz that are consistently related to the local geological conditions of the recording site. The average spectral amplifications observed for vertical and horizontal ground motions are, respectively: (1,1) for granite, (1.5, 1.6) for the Franciscan Formation, (3.0, 2.7) for the Santa Clara Formation, (3.3, 4.4) for alluvium, and (3.7, 11.3) for bay mud. Spectral amplification curves define predominant ground frequencies in the band 0.25 to 3.0 H for bay mud sites and for some alluvial sites. Amplitude spectra computed from recordings of seismic background noise at 50 sites do not generally define predominant ground frequencies. The intensities ascribed to various sites in the San Francisco Bay region for the California earthquake of April 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the intensities for 917 sites on Franciscan rocks generally decrease with the logarithm of distance as Intensity = 2.69 -- 1.90 log (Distance in kilometers). For sites on other geological units, intensity increments, derived from this empirical relation, correlate strongly with the Average Horizontal Spectral Amplifications (AHSA) according to the empirical relation Intensity Increment = 0.27 + 2.70 log (AHSA). Average intensity increments predicted for the various geological units are --0.3 for granite, 0.2 for the Franciscan Formation, 0.6 for the Great Valley sequence, 0.8 for the Santa Clara Formation, 1.3 for alluvium, and 2.4 for bay mud
Energy Technology Data Exchange (ETDEWEB)
Borcherdt, R.D.; Gibbs, J.F.
1976-04-01
Measurements of ground motion generated by nuclear explosions in Nevada have been completed for 99 locations in the San Francisco Bay region, California. The recordings show marked amplitude variations in the frequency band 0.25 to 3.0 Hz that are consistently related to the local geological conditions of the recording site. The average spectral amplifications observed for vertical and horizontal ground motions are, respectively: (1,1) for granite, (1.5, 1.6) for the Franciscan Formation, (3.0, 2.7) for the Santa Clara Formation, (3.3, 4.4) for alluvium, and (3.7, 11.3) for bay mud. Spectral amplification curves define predominant ground frequencies in the band 0.25 to 3.0 H for bay mud sites and for some alluvial sites. Amplitude spectra computed from recordings of seismic background noise at 50 sites do not generally define predominant ground frequencies. The intensities ascribed to various sites in the San Francisco Bay region for the California earthquake of April 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the intensities for 917 sites on Franciscan rocks generally decrease with the logarithm of distance as Intensity = 2.69 -- 1.90 log (Distance in kilometers). For sites on other geological units, intensity increments, derived from this empirical relation, correlate strongly with the Average Horizontal Spectral Amplifications (AHSA) according to the empirical relation Intensity Increment = 0.27 + 2.70 log (AHSA). Average intensity increments predicted for the various geological units are --0.3 for granite, 0.2 for the Franciscan Formation, 0.6 for the Great Valley sequence, 0.8 for the Santa Clara Formation, 1.3 for alluvium, and 2.4 for bay mud.
The relationship between intensity and duration of physical activity and subjective well-being.
Wicker, Pamela; Frick, Bernd
2015-10-01
Previous research documented a positive effect of physical activity on subjective well-being (SWB). Yet, mainly broad activity measures (e.g. resulting from yes-no questions) were used and the effect of different participation intensities and durations has been largely neglected. The aim of this study is to examine the effect of physical activity on SWB by focusing on participation intensity and duration. Survey data from 28 European countries are used for the analysis (n = 22 971). Two regression models (Generalized Method of Moments) are estimated which analyze the effect of participation intensity and duration on SWB (measured by life satisfaction). Given the endogeneity of the participation measures, instrumental variables are used (sport opportunities, club membership, time spent sitting). The models also control for other factors that could affect SWB (e.g. age, occupation). The results for participation intensity show that the number of days people practised at moderate intensity in the week prior to the interview have a significant and positive effect on SWB, while the number of days with vigorous-intensity activity has a significant and negative impact. Similarly, the models for duration indicate that the minutes spent on moderate-intensity activity significantly add to SWB, while the minutes spent on vigorous-intensity activity significantly reduce the level of SWB. The findings challenge the World Health Organization's recommendation in the sense that activity at moderate and vigorous intensity is not interchangeable if the aim is to also improve SWB (and not only physical health). © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.
Progress toward a microsecond duration, repetitively pulsed, intense-ion beam
Energy Technology Data Exchange (ETDEWEB)
Davis, H A; Olson, J C; Reass, W A [Los Alamos National Lab., NM (United States); Coates, D M; Hunt, J W; Schleinitz, H M [DuPont Central Research and Development, Wilmington, DE (United States); Lovberg, R H [Univ. of California, San Diego, CA (United States); Greenly, J B [Cornell Univ., Ithaca, NY (United States). Lab. of Plasma Studies
1997-12-31
A number of intense ion beams applications are emerging requiring repetitive high-average-power beams. These applications include ablative deposition of thin films, rapid melt and resolidification for surface property enhancement, advanced diagnostic neutral beams for the next generation of Tokamaks, and intense pulsed-neutron sources. A 200-250 keV, 15 kA, 1 {mu}s duration, 1-30 Hz intense ion beam accelerator is being developed to address these applications. (author). 4 figs., 7 refs.
Carbon Intensities of Economies from the Perspective of Learning Curves
Directory of Open Access Journals (Sweden)
Henrique Pacini
2014-03-01
Full Text Available While some countries have achieved considerable development, many others still lack accessto the goods and services considered standard in the modern society. As CO2 emissions and development are often correlated, this paper employs the theoretical background of the Environmental Kuznets Curve (EKC and the learning curves toolkit to analyze how carbon intensities have changed as countries move towards higher development (and cumulative wealth levels. The EKC concept is then tested with the methodology of learning curves for the period between 1971 and 2010, so as to capture a dynamic picture of emissions trends and development. Results of both analyses reveal that empirical data fails to provide direct evidence of an EKC for emissions and development. The data does show, however, an interesting pattern in the dispersion of emissions levels for countries within the same HDI categories. While data does not show that countries grow more polluting during intermediary development stages, it does provide evidence that countries become more heterogeneous in their emission intensities as they develop, later re-converging to lower emission intensities at higher HDI levels. Learning rates also indicate heterogeneity among developing countries and relative convergence among developed countries. Given the heterogeneity of development paths among countries, the experiences of those which are managing to develop at low carbon intensities can prove valuable examples for ongoing efforts in climate change mitigation, especially in the developing world.
Directory of Open Access Journals (Sweden)
Glenio G. Santos
2009-12-01
in the central and northern regions and lower intensities in the southeastern and southwestern regions of the State. These results demonstrated the importance of intensity-duration-frequency relationship and its use for studies and hydraulic projects based on data from each place.
Effects of mistuning and matrix structure on the topology of frequency response curves
Afolabi, Dare
1989-01-01
The stability of a frequency response curve under mild perturbations of the system's matrix is investigated. Using recent developments in the theory of singularities of differentiable maps, it is shown that the stability of a response curve depends on the structure of the system's matrix. In particular, the frequency response curves of a cylic system are shown to be unstable. Consequently, slight parameter variations engendered by mistuning will induce a significant difference in the topology of the forced response curves, if the mistuning transformation crosses the bifurcation set.
Multifractal rainfall extremes: Theoretical analysis and practical estimation
International Nuclear Information System (INIS)
Langousis, Andreas; Veneziano, Daniele; Furcolo, Pierluigi; Lepore, Chiara
2009-01-01
We study the extremes generated by a multifractal model of temporal rainfall and propose a practical method to estimate the Intensity-Duration-Frequency (IDF) curves. The model assumes that rainfall is a sequence of independent and identically distributed multiplicative cascades of the beta-lognormal type, with common duration D. When properly fitted to data, this simple model was found to produce accurate IDF results [Langousis A, Veneziano D. Intensity-duration-frequency curves from scaling representations of rainfall. Water Resour Res 2007;43. (doi:10.1029/2006WR005245)]. Previous studies also showed that the IDF values from multifractal representations of rainfall scale with duration d and return period T under either d → 0 or T → ∞, with different scaling exponents in the two cases. We determine the regions of the (d, T)-plane in which each asymptotic scaling behavior applies in good approximation, find expressions for the IDF values in the scaling and non-scaling regimes, and quantify the bias when estimating the asymptotic power-law tail of rainfall intensity from finite-duration records, as was often done in the past. Numerically calculated exact IDF curves are compared to several analytic approximations. The approximations are found to be accurate and are used to propose a practical IDF estimation procedure.
Salinas, J. L.; Nester, T.; Komma, J.; Bloeschl, G.
2017-12-01
Generation of realistic synthetic spatial rainfall is of pivotal importance for assessing regional hydroclimatic hazard as the input for long term rainfall-runoff simulations. The correct reproduction of observed rainfall characteristics, such as regional intensity-duration-frequency curves, and spatial and temporal correlations is necessary to adequately model the magnitude and frequency of the flood peaks, by reproducing antecedent soil moisture conditions before extreme rainfall events, and joint probability of flood waves at confluences. In this work, a modification of the model presented by Bardossy and Platte (1992), where precipitation is first modeled on a station basis as a multivariate autoregressive model (mAr) in a Normal space. The spatial and temporal correlation structures are imposed in the Normal space, allowing for a different temporal autocorrelation parameter for each station, and simultaneously ensuring the positive-definiteness of the correlation matrix of the mAr errors. The Normal rainfall is then transformed to a Gamma-distributed space, with parameters varying monthly according to a sinusoidal function, in order to adapt to the observed rainfall seasonality. One of the main differences with the original model is the simulation time-step, reduced from 24h to 6h. Due to a larger availability of daily rainfall data, as opposite to sub-daily (e.g. hourly), the parameters of the Gamma distributions are calibrated to reproduce simultaneously a series of daily rainfall characteristics (mean daily rainfall, standard deviations of daily rainfall, and 24h intensity-duration-frequency [IDF] curves), as well as other aggregated rainfall measures (mean annual rainfall, and monthly rainfall). The calibration of the spatial and temporal correlation parameters is performed in a way that the catchment-averaged IDF curves aggregated at different temporal scales fit the measured ones. The rainfall model is used to generate 10.000 years of synthetic
Demaria, E. M.; Goodrich, D. C.; Keefer, T.
2017-12-01
Observed sub-daily precipitation intensities from contrasting hydroclimatic environments in the USA are used to evaluate temporal trends and to develop Intensity-Duration Frequency (IDF) curves under stationary and nonstationary climatic conditions. Analyses are based on observations from two United States Department of Agriculture (USDA)-Agricultural Research Service (ARS) experimental watersheds located in a semi-arid and a temperate environment. We use an Annual Maximum Series (AMS) and a Partial Duration Series (PDS) approach to identify temporal trends in maximum intensities for durations ranging from 5- to 1440-minutes. A Bayesian approach with Monte Carlo techniques is used to incorporate the effect of non-stationary climatic assumptions in the IDF curves. The results show increasing trends in observed AMS sub-daily intensities in both watersheds whereas trends in the PDS observations are mostly positive in the semi-arid site and a mix of positive and negative in the temperate site. Stationary climate assumptions lead to much lower estimated sub-daily intensities than those under non-stationary assumptions with larger absolute differences found for shorter durations and smaller return periods. The risk of failure (R) of a hydraulic structure is increased for non-stationary effects over those of stationary effects, with absolute differences of 25% for a 100-year return period (T) and a project life (n) of 100 years. The study highlights the importance of considering non-stationarity, due to natural variability or to climate change, in storm design.
International Nuclear Information System (INIS)
Tu, Jien-Yi; Chou Chia
2013-01-01
The hourly rainfall at 21 ground stations in Taiwan is used to investigate changes in the frequency, intensity, and duration of rainfall, which can be divided into typhoon and non-typhoon rainfall, in the period of 1970–2010. As a whole, the frequency of rainfall shows a decreasing trend for lighter rain and an increasing trend for heavier rain. Also, the typhoon rainfall shows a significant increase for all intensities, while the non-typhoon rainfall exhibits a general trend of decreasing, particularly for lighter rain. In rainfall intensity, both typhoon and non-typhoon rainfall extremes become more intense, with an increased rate much greater than the Clausius–Clapeyron thermal scaling. Moreover, rainfall extremes associated with typhoons have tended to affect Taiwan rainfall for longer in recent decades. The more frequent, intense and long-lasting typhoon rainfall is mainly induced by the slower translation speed of the typhoons over the neighborhood of Taiwan, which could be associated with a weakening of steering flow in the western North Pacific and the northern South China Sea. (letter)
Smith, A; Pedler, A
2018-01-01
Various conditioned pain modulation (CPM) methodologies have been used to investigate diffuse noxious inhibitory control pain mechanisms in healthy and clinical populations. Occlusion cuff parameters have been poorly studied. We aimed to investigate whether occlusion cuff intensity and/or duration influenced CPM magnitudes. We also investigated the role of physical activity levels on CPM magnitude. Two studies were performed to investigate the role of intensity and duration of occlusion cuff conditioning stimulus on test stimulus (tibialis anterior pressure pain thresholds). In Study 1, conditioning stimulus intensity of 2/10 or 5/10 (duration CPM magnitude. In Study 1, 27 healthy volunteers (mean ± SD: 24.9 years (±4.5); eight female) demonstrated that an occlusion cuff applied to the upper arm eliciting 5/10 local pain resulted in a significant (mean ± SD: 17% ± 46%) increase in CPM magnitude, when compared to 2/10 intensity (-3% ± 38%, p = 0.026), whereas in Study 2, 25 healthy volunteers (22.5 years (±2.7); 13 female) demonstrated that 3 min of 2/10 CS intensity did not result in a significant change in CPM (p = 0.21). There was no significant relationship between physical activity levels and CPM in either study (p > 0.22). This study demonstrated that an occlusion cuff of 5/10 conditioning stimulus intensity, when compared to 2/10, significantly increased CPM magnitude. Maintaining 2/10 conditioning stimulus for 3 min did not increase CPM magnitude. Dysfunctional conditioned pain modulation (CPM) has been associated with poor health outcomes. Various factors can influence CPM outcomes. The role of occlusion cuff conditioning stimulus intensity and duration has not been previously investigated. Intensity (5/10), but not duration of lower intensity (2/10) conditioning stimulus, affects CPM magnitude. © 2017 European Pain Federation - EFIC®.
Fonseca, P. M.; Veiga, J. A.; Correia, F. S.; Brito, A. L.
2013-05-01
The aim of this research was evaluate changes in frequency and intensity of extreme events of precipitation in Brazilian Amazon and Northeast Region, doubling CO2 concentration in agreement of IPCC A2 emissions scenarios (Nakicenovic et al., 2001). For this evaluation was used ETA model (Chou et al., 2011), forced with CCSM3 Global model data (Meehl, 2006) to run 4 experiments, only for January, February and March: 1980-1990, 2000-2010, 2040-2050 and 2090-2100. Using the first decade as reference (1980-1990), was evaluated changes occurred in following decades, with a methodology to classify extremes events adapted from Frich (2002) and Gao (2006). Higher was the class, more intense is the event. An increase of 25% was observed in total precipitation in Brazilian Amazon for the end of XXI century and 12% for extreme events type 1, 9% for events type 2 and 10% for type 3. By the other hand, a 17% decrease of precipitation in Brazilian Northeast was observed, and a pronounced decay of 24% and 15% in extreme events contribution type 1 and 2 to total amount of precipitation, respectively. The difference between total normal type events was positive in this three decades compared with reference decade 1980-1990, varying positively from 4 to 6 thousand events included in normality by decade, these events was decreased in your majority of Class 1 events, which presented a decay of at least 3.500 events by each decade. This suggests an intensification of extreme events, considering that the amount of precipitation by class increased, and the number of events by class decreased. To Northeast region, an increasing in 9% of contribution to events type 3 class was observed, as well as in the frequency of this type of events (about of 700 more events). Major decreasing in number of classes extreme events occur in 2000-2010, to classes 1 and 3, with 7,2 and 5,6%, and by the end of century in class 3, with 4,5%. For the three analyzed decades a total decrease of 8.400 events was
International Nuclear Information System (INIS)
Belmont, G.
1981-01-01
Intense natural waves are commonly observed onboard satellites in the outer earth's magnetosphere, inside a narrow frequency range, including the electron plasma and upper hybrid frequencies. In order to progress in the understanding of their emission processes, it is necessary to determine precisely the relationship which exists between their frequencies and the characteristic frequencies of the magnetospheric plasma. For this purpose, it is necessary to take into account the fact that some of these characteristic frequencies, which are provided by active sounding of the plasma, not only depend on the total density, but also on the shape of the distribution function (which has generally been assumed to be Maxwellian). A method providing a fine diagnosis of general non-Maxwellian plasmas is developed. This method of analysis of the experimental data is based on a theoretical study which points out the influence of the shape of the distribution function on the dispersion curves (for wave vectors perpendicular to the static magnetic field)
International Nuclear Information System (INIS)
Fang Junchu; Chen Ming; Sun Huifen
2008-01-01
Objective: To study the characters of time-intensity curve of contrast-enhanced ultrasonography in benign prostate hyperplasia (BPH) and prostate cancer. Methods: 2.4 ml Sono Vue were injected as a bolus in 40 patients, 23 patients with BPH and 17 with prostate cancer. High perfusion area in both inner and outer gland were measured with time-intensity curves. Results: It was proved by the time-intensity curves that, in BPH cases, the outer prostate gland presented with mild enhancedment and slow wash-off, while the inner gland presented with moderate enhancedment and fast wash-off. Otherwise, both the inner and outer gland in prostate cancer cases presented with high-intensitive enhancedment and slow wash-off. There was marked difference statistical significance on the up slop, average intensity and area under the time-intensity curves in 90 s and 150 s between the cases of BPH and prostate cancer (P<0.05, P<0.01). Conclusion: Quantitative analysis of high perfusion area in both inner and outer glands is helpful for diagnosing BPH and prostate cancer. (authors)
Evaluation of different pre-slaughter light intensities and fasting duration in broilers
Directory of Open Access Journals (Sweden)
IB Ramão
2011-12-01
Full Text Available The aim of this study was to determine the effects of different levels of light intensity (0, 5 or 20 lx and different pre-slaughter feed fasting duration (3, 6, 9, 12 and 15 hours on the parameters body weight loss, carcass yield, commercial cuts yield, water carcass retention, bacterial counts and breast meat pH. A number of 72 broiler chickens at 45 days of age (Cobb 500 strain was distributed in three chambers, in a total of 24 broilers per chamber. The results showed that feed fasting significantly influenced (p0.05. The presence of feed in the crop and gizzard did not depend on light intensity, but was affected by pre-slaughter feed fasting duration. Bacterial counts decreased with feed fasting duration (p<0.05.
Directory of Open Access Journals (Sweden)
E. Sauquet
2011-08-01
Full Text Available The study aims at estimating flow duration curves (FDC at ungauged sites in France and quantifying the associated uncertainties using a large dataset of 1080 FDCs. The interpolation procedure focuses here on 15 percentiles standardised by the mean annual flow, which is assumed to be known at each site. In particular, this paper discusses the impact of different catchment grouping procedures on the estimation of percentiles by regional regression models.
In a first step, five parsimonious FDC parametric models are tested to approximate FDCs at gauged sites. The results show that the model based on the expansion of Empirical Orthogonal Functions (EOF outperforms the other tested models. In the EOF model, each FDC is interpreted as a linear combination of regional amplitude functions with spatially variable weighting factors corresponding to the parameters of the model. In this approach, only one amplitude function is required to obtain a satisfactory fit with most of the observed curves. Thus, the considered model requires only two parameters to be applicable at ungauged locations.
Secondly, homogeneous regions are derived according to hydrological response, on the one hand, and geological, climatic and topographic characteristics on the other hand. Hydrological similarity is assessed through two simple indicators: the concavity index (IC representing the shape of the dimensionless FDC and the seasonality ratio (SR, which is the ratio of summer and winter median flows. These variables are used as homogeneity criteria in three different methods for grouping catchments: (i according to an a priori classification of French Hydro-EcoRegions (HERs, (ii by applying regression tree clustering and (iii by using neighbourhoods obtained by canonical correlation analysis.
Finally, considering all the data, and subsequently for each group obtained through the tested grouping techniques, we derive regression models between
Ferguson, Carrie; Wilson, John; Birch, Karen M.; Kemi, Ole J.
2013-01-01
The tolerable duration of continuous high-intensity exercise is determined by the hyperbolic Speed-tolerable duration (S-tLIM) relationship. However, application of the S-tLIM relationship to normalize the intensity of High-Intensity Interval Training (HIIT) has yet to be considered, with this the aim of present study. Subjects completed a ramp-incremental test, and series of 4 constant-speed tests to determine the S-tLIM relationship. A sub-group of subjects (n = 8) then repeated 4 min bouts of exercise at the speeds predicted to induce intolerance at 4 min (WR4), 6 min (WR6) and 8 min (WR8), interspersed with bouts of 4 min recovery, to the point of exercise intolerance (fixed WR HIIT) on different days, with the aim of establishing the work rate that could be sustained for 960 s (i.e. 4×4 min). A sub-group of subjects (n = 6) also completed 4 bouts of exercise interspersed with 4 min recovery, with each bout continued to the point of exercise intolerance (maximal HIIT) to determine the appropriate protocol for maximizing the amount of high-intensity work that can be completed during 4×4 min HIIT. For fixed WR HIIT tLIM of HIIT sessions was 399±81 s for WR4, 892±181 s for WR6 and 1517±346 s for WR8, with total exercise durations all significantly different from each other (PHIIT, there was no difference in tLIM of each of the 4 bouts (Bout 1: 229±27 s; Bout 2: 262±37 s; Bout 3: 235±49 s; Bout 4: 235±53 s; P>0.050). However, there was significantly less high-intensity work completed during bouts 2 (153.5±40. 9 m), 3 (136.9±38.9 m), and 4 (136.7±39.3 m), compared with bout 1 (264.9±58.7 m; P>0.050). These data establish that WR6 provides the appropriate work rate to normalize the intensity of HIIT between subjects. Maximal HIIT provides a protocol which allows the relative contribution of the work rate profile to physiological adaptations to be considered during alternative intensity-matched HIIT protocols. PMID:24244266
Moriyama, Shingo; Yoshida, Soichiro; Tanaka, Hajime; Tanaka, Hiroshi; Yokoyama, Minato; Ishioka, Junichiro; Matsuoka, Yoh; Saito, Kazutaka; Kihara, Kazunori; Fujii, Yasuhisa
2018-03-25
To assess the diagnostic ability of a pixel intensity-based analysis in evaluating the magnetic resonance imaging characteristics of small renal masses, especially in differentiating fat-poor angiomyolipoma from renal cell carcinoma. T2-weighted images from 121 solid small renal masses (ratio curve was plotted using intensity ratios, which were ratios of signal intensities of tumor pixels (each pixel along a linear region of interest drawn across the renal tumor on T2-weighted image) to the signal intensity of a normal renal cortex. The diagnostic ability of the intensity ratio curve analysis was evaluated. The tumors were classified into three types: intensity ratio fat-poor angiomyolipoma (n = 19) with no pseudocapsule, iso-low intensity and no heterogeneity; intensity ratio clear cell renal cell carcinoma (n = 76) with a pseudocapsule, iso-high intensity and heterogeneity; and other type of intensity ratio (n = 26), including tumors that did not fall into the above two categories. The sensitivity/specificity/accuracy of the intensity ratio curve analysis in diagnosing fat-poor angiomyolipoma was 93%/94%/94%, respectively. When the intensity ratio curve analysis was applied only to the tumor with undetermined radiological diagnosis, the sensitivity for diagnosing fat-poor angiomyolipoma compared with subjective reading alone significantly improved (93% vs 50%; P = 0.014). Our novel semiquantitative model for combined assessment of key features of fat-poor angiomyolipoma, including low intensity, homogeneity and absence of a pseudocapsule on T2-weighted image, might make diagnosis of fat-poor angiomyolipoma more accurate. © 2018 The Japanese Urological Association.
Turcksin, Rivka; Bel, Sarah; Galjaard, Sander; Devlieger, Roland
2014-04-01
This systematic review investigates the relationship between maternal obesity and breastfeeding intention, initiation, intensity, duration and milk supply. A comprehensive search was performed through three major databases, including Medline, Cochrane Library and Cumulative Index For Nursing and Allied Health Literature, and by screening reference lists of the relevant publications. Selection criteria were: report of original research, studies on low-risk obese mothers and the comparison with normal weight mothers which met at least two of the following primary outcomes: breastfeeding intention; initiation; intensity; duration and/or milk supply. Furthermore, the included reports had to contain a clear definition of pre-pregnant obesity, use compensation mechanisms for potential confounding factors, have a prospective cohort design and had to have been published between 1997 and 2011 and in English, French or Dutch. Effects of obesity on breastfeeding intention, initiation, intensity, duration and milk supply were analysed, tabulated and summarised in this review. Studies have found that obese women are less likely to intend to breastfeed and that maternal obesity seems to be associated with a decreased initiation of breastfeeding, a shortened duration of breastfeeding, a less adequate milk supply and delayed onset of lactogenesis II, compared with their normal weight counterparts. This systematic review indicates therefore that maternal obesity is an adverse determinant for breastfeeding success. © 2012 JohnWiley & Sons Ltd.
International Nuclear Information System (INIS)
Davis, H.A.; Bartsch, R.R.; Barnes, C.W.
1996-01-01
The authors describe the design of an intense, pulsed, repetitive, neutral beam based on magnetically insulated diode technology for injection into ITER for spectroscopic measurements of thermalizing alpha particle and thermal helium density profiles, ion temperature, plasma rotation, and low Z impurity concentrations in the confinement region. The beam is being developed to enhance low signal-to-noise ratios expected with conventional steady-state ion beams because of severe beam attenuation and intense bremstrahlung emission. A 5 GW (e.g., 100 keV, 50 kA) one-microsecond-duration beam would increase the signal by 10 3 compared to a conventional 5 MW beam with signal-to-noise ratios comparable to those from a chopped conventional beam in one second
Geometric Structure of 3D Spinal Curves: Plane Regions and Connecting Zones
Berthonnaud, E.; Hilmi, R.; Dimnet, J.
2012-01-01
This paper presents a new study of the geometric structure of 3D spinal curves. The spine is considered as an heterogeneous beam, compound of vertebrae and intervertebral discs. The spine is modeled as a deformable wire along which vertebrae are beads rotating about the wire. 3D spinal curves are compound of plane regions connected together by zones of transition. The 3D spinal curve is uniquely flexed along the plane regions. The angular offsets between adjacent regions are concentrated at level of the middle zones of transition, so illustrating the heterogeneity of the spinal geometric structure. The plane regions along the 3D spinal curve must satisfy two criteria: (i) a criterion of minimum distance between the curve and the regional plane and (ii) a criterion controlling that the curve is continuously plane at the level of the region. The geometric structure of each 3D spinal curve is characterized by the sizes and orientations of regional planes, by the parameters representing flexed regions and by the sizes and functions of zones of transition. Spinal curves of asymptomatic subjects show three plane regions corresponding to spinal curvatures: lumbar, thoracic and cervical curvatures. In some scoliotic spines, four plane regions may be detected. PMID:25031873
Energy Technology Data Exchange (ETDEWEB)
Matsumoto, Kenji; Ehara, Shoichi; Hasegawa, Takao; Sakaguchi, Mikumo; Shimada, Kenei [Osaka City University Graduate School of Medicine, Department of Cardiovascular Medicine, Abeno-ku, Osaka (Japan)
2017-09-15
To evaluate the association between duration of the coronary occlusion and high-intensity signal (HIS) on noncontrast T1-weighted imaging using a 1.5-T magnetic resonance imager among patients with angiographic coronary total occlusion. The signal intensity of the coronary target area divided by the signal intensity of the left ventricular muscle near the target area at each site (TMR) was measured. Areas with a TMR >1.0 were defined as HIS. Thirty five lesions from 33 patients were divided into the following three groups: subacute occlusion (up to 3 months; n = 7), short-duration chronic total occlusion (SD-CTO: 3-6 months; n = 9) and long-duration CTO (LD-CTO: ≥6 months; n = 19). All subacute occlusion lesions showed a HIS within the occlusion site. Among patients with CTO, the frequency of a HIS within the occlusion site was significantly higher in SD-CTO than in LD-CTO lesions (p = 0.013). In multivariate analyses, only an occlusion duration of less than 6 months was an independent factor associated with the presence of HIS (odds ratio 7.6, 95% CI 1.1-54.5; p = 0.044). The presence of a HIS in the occlusion site was associated more with SD-CTO than with LD-CTO among patients with CTO. (orig.)
International Nuclear Information System (INIS)
Matsumoto, Kenji; Ehara, Shoichi; Hasegawa, Takao; Sakaguchi, Mikumo; Shimada, Kenei
2017-01-01
To evaluate the association between duration of the coronary occlusion and high-intensity signal (HIS) on noncontrast T1-weighted imaging using a 1.5-T magnetic resonance imager among patients with angiographic coronary total occlusion. The signal intensity of the coronary target area divided by the signal intensity of the left ventricular muscle near the target area at each site (TMR) was measured. Areas with a TMR >1.0 were defined as HIS. Thirty five lesions from 33 patients were divided into the following three groups: subacute occlusion (up to 3 months; n = 7), short-duration chronic total occlusion (SD-CTO: 3-6 months; n = 9) and long-duration CTO (LD-CTO: ≥6 months; n = 19). All subacute occlusion lesions showed a HIS within the occlusion site. Among patients with CTO, the frequency of a HIS within the occlusion site was significantly higher in SD-CTO than in LD-CTO lesions (p = 0.013). In multivariate analyses, only an occlusion duration of less than 6 months was an independent factor associated with the presence of HIS (odds ratio 7.6, 95% CI 1.1-54.5; p = 0.044). The presence of a HIS in the occlusion site was associated more with SD-CTO than with LD-CTO among patients with CTO. (orig.)
Hanley, Torrance C; Kimbro, David L; Hughes, Anne Randall
2017-07-01
Environmental perturbations can strongly affect community processes and ecosystem functions by acting primarily as a subsidy that increases productivity, a stress that decreases productivity, or both, with the predominant effect potentially shifting from subsidy to stress as the overall intensity of the perturbation increases. While perturbations are often considered along a single axis of intensity, they consist of multiple components (e.g., magnitude, frequency, and duration) that may not have equivalent stress and/or subsidy effects. Thus, different combinations of perturbation components may elicit community and ecosystem responses that differ in strength and/or direction (i.e., stress or subsidy) even if they reflect a similar overall perturbation intensity. To assess the independent and interactive effects of perturbation components, we experimentally manipulated the magnitude, frequency, and duration of wrack deposition, a common stress-subsidy in a variety of coastal systems. The effects of wrack perturbation on salt marsh community and ecosystem properties were assessed both in the short-term (at the end of a 12-week experimental manipulation) and long-term (6 months after the end of the experiment). In the short-term, plants and associated benthic invertebrates exhibited primarily stress-based responses to wrack perturbation. The extent of these stress effects on density of the dominant plant Spartina alterniflora, total plant percent cover, invertebrate abundance, and sediment oxygen availability were largely determined by perturbation duration. Yet, higher nitrogen content of Spartina, which indicates a subsidy effect of wrack, was influenced primarily by perturbation magnitude in the short-term. In the longer term, perturbation magnitude determined the extent of both stress and subsidy effects of wrack perturbation, with lower subordinate plant percent cover and snail density, and higher Spartina nitrogen content in high wrack biomass treatments
Trends in Northern Hemisphere surface cyclone frequency and intensity
McCabe, G.J.; Clark, M.P.; Serreze, Mark C.
2001-01-01
One of the hypothesized effects of global warming from increasing concentrations of greenhouse gases is a change in the frequency and/or intensity of extratropical cyclones. In this study, winter frequencies and intensities of extratropical cyclones in the Northern Hemisphere for the period 1959-97 are examined to determine if identifiable trends are occurring. Results indicate a statistically significant decrease in midlatitude cyclone frequency and a significant increase in high-latitude cyclone frequency. In addition, storm intensity has increased in both the high and midlatitudes. The changes in storm frequency correlate with changes in winter Northern Hemisphere temperature and support hypotheses that global warming may result in a northward shift of storm tracks in the Northern Hemisphere.
Directory of Open Access Journals (Sweden)
Ashish Shrestha
2017-02-01
Full Text Available The magnitude and frequency of hydrological events are expected to increase in coming years due to climate change in megacities of Asia. Intensity–Duration–Frequency (IDF curves represent essential means to study effects on the performance of drainage systems. Therefore, the need for updating IDF curves comes from the necessity to gain better understanding of climate change effects. The present paper explores an approach based on spatial downscaling-temporal disaggregation method (DDM to develop future IDFs using stochastic weather generator, Long Ashton Research Station Weather Generator (LARS-WG and the rainfall disaggregation tool, Hyetos. The work was carried out for the case of Bangkok, Thailand. The application of LARS-WG to project extreme rainfalls showed promising results and nine global climate models (GCMs were used to estimate changes in IDF characteristics for future time periods of 2011–2030 and 2046–2065 under climate change scenarios. The IDFs derived from this approach were corrected using higher order equation to mitigate biases. IDFs from all GCMs showed increasing intensities in the future for all return periods. The work presented demonstrates the potential of this approach in projecting future climate scenarios for urban catchment where long term hourly rainfall data are not readily available.
Gómez, Wilmar
2017-04-01
By analyzing the spatial and temporal variability of extreme precipitation events we can prevent or reduce the threat and risk. Many water resources projects require joint probability distributions of random variables such as precipitation intensity and duration, which can not be independent with each other. The problem of defining a probability model for observations of several dependent variables is greatly simplified by the joint distribution in terms of their marginal by taking copulas. This document presents a general framework set frequency analysis bivariate and multivariate using Archimedean copulas for extreme events of hydroclimatological nature such as severe storms. This analysis was conducted in the lower Tunjuelo River basin in Colombia for precipitation events. The results obtained show that for a joint study of the intensity-duration-frequency, IDF curves can be obtained through copulas and thus establish more accurate and reliable information from design storms and associated risks. It shows how the use of copulas greatly simplifies the study of multivariate distributions that introduce the concept of joint return period used to represent the needs of hydrological designs properly in frequency analysis.
Influence of Intensity and Duration of Yoga on Anxiety and ...
African Journals Online (AJOL)
Background: Chronic illness is commonly associated with anxiety and depression. Both anxiety and depression respond to yoga. However, there is no report on the association between the intensity and duration of yoga practice with the benefits seen. Aim: The present study was intended to determine whether the daily ...
Development of a precipitation-area curve for warning criteria of short-duration flash flood
Bae, Deg-Hyo; Lee, Moon-Hwan; Moon, Sung-Keun
2018-01-01
This paper presents quantitative criteria for flash flood warning that can be used to rapidly assess flash flood occurrence based on only rainfall estimates. This study was conducted for 200 small mountainous sub-catchments of the Han River basin in South Korea because South Korea has recently suffered many flash flood events. The quantitative criteria are calculated based on flash flood guidance (FFG), which is defined as the depth of rainfall of a given duration required to cause frequent flooding (1-2-year return period) at the outlet of a small stream basin and is estimated using threshold runoff (TR) and antecedent soil moisture conditions in all sub-basins. The soil moisture conditions were estimated during the flooding season, i.e., July, August and September, over 7 years (2002-2009) using the Sejong University Rainfall Runoff (SURR) model. A ROC (receiver operating characteristic) analysis was used to obtain optimum rainfall values and a generalized precipitation-area (P-A) curve was developed for flash flood warning thresholds. The threshold function was derived as a P-A curve because the precipitation threshold with a short duration is more closely related to basin area than any other variables. For a brief description of the P-A curve, generalized thresholds for flash flood warnings can be suggested for rainfall rates of 42, 32 and 20 mm h-1 in sub-basins with areas of 22-40, 40-100 and > 100 km2, respectively. The proposed P-A curve was validated based on observed flash flood events in different sub-basins. Flash flood occurrences were captured for 9 out of 12 events. This result can be used instead of FFG to identify brief flash flood (less than 1 h), and it can provide warning information to decision-makers or citizens that is relatively simple, clear and immediate.
Lagomarsino, Daniela; Rosi, Ascanio; Rossi, Guglielmo; Segoni, Samuele; Catani, Filippo
2014-05-01
This work makes a quantitative comparison between the results of landslide forecasting obtained using two different rainfall threshold models, one using intensity-duration thresholds and the other based on cumulative rainfall thresholds in an area of northern Tuscany of 116 km2. The first methodology identifies rainfall intensity-duration thresholds by means a software called MaCumBA (Massive CUMulative Brisk Analyzer) that analyzes rain-gauge records, extracts the intensities (I) and durations (D) of the rainstorms associated with the initiation of landslides, plots these values on a diagram, and identifies thresholds that define the lower bounds of the I-D values. A back analysis using data from past events can be used to identify the threshold conditions associated with the least amount of false alarms. The second method (SIGMA) is based on the hypothesis that anomalous or extreme values of rainfall are responsible for landslide triggering: the statistical distribution of the rainfall series is analyzed, and multiples of the standard deviation (σ) are used as thresholds to discriminate between ordinary and extraordinary rainfall events. The name of the model, SIGMA, reflects the central role of the standard deviations in the proposed methodology. The definition of intensity-duration rainfall thresholds requires the combined use of rainfall measurements and an inventory of dated landslides, whereas SIGMA model can be implemented using only rainfall data. These two methodologies were applied in an area of 116 km2 where a database of 1200 landslides was available for the period 2000-2012. The results obtained are compared and discussed. Although several examples of visual comparisons between different intensity-duration rainfall thresholds are reported in the international literature, a quantitative comparison between thresholds obtained in the same area using different techniques and approaches is a relatively undebated research topic.
The effect of composition feed mixtures on curve of hens laying intensity
Directory of Open Access Journals (Sweden)
Emil Mareček
2005-01-01
Full Text Available The experiment was done in the experimental station ÚKZÚZ Havlíčkův Brod. There were four experimental groups (N1, N2, N3, N4 of laying hens and weekly laying intensity was observed. Hybrid ISA BROWN was used in the experiment, 405 hens in each group. The laying intensity was observed from the start of laying for 44 weeks. During laying four different diets were fed to laying hens (N1 – control group with fish meal, N2 – control group containing only of plant protein sources, N3 – experimental group with higher content of rapeseed, N4 – experimental group containing treated rapeseed. Yang model was used for the evaluation of laying curves and we found following parameters of the curves:Yang model N1: y = 97.28 * e – 0.004 * t / [1 + e – 2.054 (t – 2.549]\tR2 = 0.97Yang model N2: y = 98.29 * e – 0.006 * t / [1 + e – 2.071 (t – 2.668]\tR2 = 0.96Yang model N3: y = 98.49 * e – 0.005 * t / [1 + e – 1.856 (t – 2.568]\tR2 = 0.97Yang model N4: y = 98.55 * e – 0.005 * t / [1 + e – 2.251 (t – 2.615].\tR2 = 0.97The results document that experimental treatments had small effect on the parameters of laying curves. It means that rapeseed had only small effect on the laying intensity and also the elimination of animal protein from the diet for laying hens had not effect on laying intensity. On the base of our results we estimated the standard equation for evaluation of laying curve:Yang model: y = 98.15 * e – 0.005 * t / [1 + e – 2.058 (t – 2.601].\tR2 = 0.99This equation can be used as standard for evaluation of laying intensity after experimental treatments or for evaluation of laying intensity of different hybrids.
Changes in Intense Precipitation Events in West Africa and the central U.S. under Global Warming
Energy Technology Data Exchange (ETDEWEB)
Cook, Kerry H. [Univ. of Texas, Austin, TX (United States); Vizy, Edward [Univ. of Texas, Austin, TX (United States)
2016-02-08
The purpose of the proposed project is to improve our understanding of the physical processes and large-scale connectivity of changes in intense precipitation events (high rainfall rates) under global warming in West Africa and the central U.S., including relationships with low-frequency modes of variability. This is in response to the requested subject area #2 “simulation of climate extremes under a changing climate … to better quantify the frequency, duration, and intensity of extreme events under climate change and elucidate the role of low frequency climate variability in modulating extremes.” We will use a regional climate model and emphasize an understanding of the physical processes that lead to an intensification of rainfall. The project objectives are as follows: 1. Understand the processes responsible for simulated changes in warm-season rainfall intensity and frequency over West Africa and the Central U.S. associated with greenhouse gas-induced global warming 2. Understand the relationship between changes in warm-season rainfall intensity and frequency, which generally occur on regional space scales, and the larger-scale global warming signal by considering modifications of low-frequency modes of variability. 3. Relate changes simulated on regional space scales to global-scale theories of how and why atmospheric moisture levels and rainfall should change as climate warms.
Classifying low flow hydrological regimes at a regional scale
Kirkby, M. J.; Gallart, F.; Kjeldsen, T. R.; Irvine, B. J.; Froebrich, J.; Lo Porto, A.; de Girolamo, A.; Mirage Team
2011-12-01
The paper uses a simple water balance model that partitions the precipitation between actual evapotranspiration, quick flow and delayed flow, and has sufficient complexity to capture the essence of climate and vegetation controls on this partitioning. Using this model, monthly flow duration curves have been constructed from climate data across Europe to address the relative frequency of ecologically critical low flow stages in semi-arid rivers, when flow commonly persists only in disconnected pools in the river bed. The hydrological model is based on a dynamic partitioning of precipitation to estimate water available for evapotranspiration and plant growth and for residual runoff. The duration curve for monthly flows has then been analysed to give an estimate of bankfull flow based on recurrence interval. Arguing from observed ratios of cross-sectional areas at flood and low flows, hydraulic geometry suggests that disconnected flow under "pool" conditions is approximately 0.1% of bankfull flow. Flow duration curves define a measure of bankfull discharge on the basis of frequency. The corresponding frequency for pools is then read from the duration curve, using this (0.1%) ratio to estimate pool discharge from bank full discharge. The flow duration curve then provides an estimate of the frequency of poorly connected pool conditions, corresponding to this discharge, that constrain survival of river-dwelling arthropods and fish. The methodology has here been applied across Europe at 15 km resolution, and the potential is demonstrated for applying the methodology under alternative climatic scenarios.
On the duration and intensity of cumulative advantage competitions
International Nuclear Information System (INIS)
Jiang, Bo; Towsley, Don; Sun, Liyuan; Figueiredo, Daniel R; Ribeiro, Bruno
2015-01-01
Network growth can be framed as a competition for edges among nodes in the network. As with various other social and physical systems, skill (fitness) and luck (random chance) act as fundamental forces driving competition dynamics. In the context of networks, cumulative advantage (CA)—the rich-get-richer effect—is seen as a driving principle governing the edge accumulation process. However, competitions coupled with CA exhibit non-trivial behavior and little is formally known about duration and intensity of CA competitions. By isolating two nodes in an ideal CA competition, we provide a mathematical understanding of how CA exacerbates the role of luck in detriment of skill. We show, for instance, that when nodes start with few edges, an early stroke of luck can place the less skilled in the lead for an extremely long period of time, a phenomenon we call ‘struggle of the fittest’. We prove that duration of a simple skill and luck competition model exhibit power-law tails when CA is present, regardless of skill difference, which is in sharp contrast to the exponential tails when fitness is distinct but CA is absent. We also prove that competition intensity is always upper bounded by an exponential tail, irrespective of CA and skills. Thus, CA competitions can be extremely long (infinite mean, depending on fitness ratio) but almost never very intense. The theoretical results are corroborated by extensive numerical simulations. Our findings have important implications to competitions not only among nodes in networks but also in contexts that leverage socio-physical models embodying CA competitions. (paper)
On the duration and intensity of cumulative advantage competitions
Jiang, Bo; Sun, Liyuan; Figueiredo, Daniel R.; Ribeiro, Bruno; Towsley, Don
2015-11-01
Network growth can be framed as a competition for edges among nodes in the network. As with various other social and physical systems, skill (fitness) and luck (random chance) act as fundamental forces driving competition dynamics. In the context of networks, cumulative advantage (CA)—the rich-get-richer effect—is seen as a driving principle governing the edge accumulation process. However, competitions coupled with CA exhibit non-trivial behavior and little is formally known about duration and intensity of CA competitions. By isolating two nodes in an ideal CA competition, we provide a mathematical understanding of how CA exacerbates the role of luck in detriment of skill. We show, for instance, that when nodes start with few edges, an early stroke of luck can place the less skilled in the lead for an extremely long period of time, a phenomenon we call ‘struggle of the fittest’. We prove that duration of a simple skill and luck competition model exhibit power-law tails when CA is present, regardless of skill difference, which is in sharp contrast to the exponential tails when fitness is distinct but CA is absent. We also prove that competition intensity is always upper bounded by an exponential tail, irrespective of CA and skills. Thus, CA competitions can be extremely long (infinite mean, depending on fitness ratio) but almost never very intense. The theoretical results are corroborated by extensive numerical simulations. Our findings have important implications to competitions not only among nodes in networks but also in contexts that leverage socio-physical models embodying CA competitions.
High-frequency, high-intensity photoionization
Reiss, H. R.
1996-02-01
Two analytical methods for computing ionization by high-frequency fields are compared. Predicted ionization rates compare well, but energy predictions for the onset of ionization differ radically. The difference is shown to arise from the use of a transformation in one of the methods that alters the zero from which energy is measured. This alteration leads to an apparent energy threshold for ionization that can, especially in the stabilization regime, differ strongly from the laboratory measurement. It is concluded that channel closings in intense-field ionization can occur at high as well as low frequencies. It is also found that the stabilization phenomenon at high frequencies, very prominent for hydrogen, is absent in a short-range potential.
KIRIHARA, RICARDO AKIHIRO; CATELAN, FELLIPE BRAVIM; FARIAS, FABIANE ELIZE SABINO DE; SILVA, CLEIDNÉIA APARECIDA CLEMENTE DA; CERNIGOY, CLAUDIA HELENA DE AZEVEDO; REZENDE, MÁRCIA UCHOA DE
2017-01-01
ABSTRACT Objective: To evaluate the effects of physical activity intensity, type and duration in patients with knee osteoarthritis (KOA). Methods: A retrospective study of 195 KOA patients who were followed for two years after receiving educational material about KOA with or without attending classes. The patients were evaluated at baseline and 24 months. At the evaluations, the patients answered questionnaires pertaining to pain and function (WOMAC, Lequesne, VAS and SF-36); reported the intensity, duration and type of exercise performed per week; and performed the Timed Up & Go (TUG) and Five Times Sit-to-Stand (FTSST) tests. Results: Increased age affected improvements in the TUG results (p=0.017). The type, intensity and duration of physical activity did not correlate with pain, function or quality of life improvements (p>0.05), but the TUG results were on average 4 seconds faster among the patients who practiced intense physical activity and/or exercised for more than 180 minutes per week and/or performed isolated weight training or swam compared with those who remained sedentary after 2 years (p=0.01; pbodybuilding) for relevant pain reduction and functional improvement.Level of Evidence II, Retrospective Study. PMID:28642646
Vero, Sara E.; Healy, Mark G.; Henry, Tiernan; Creamer, Rachel E.; Ibrahim, Tristan G.; Forrestal, Patrick J.; Richards, Karl G.; Fenton, Owen
2016-01-01
During laboratory assessment of the soil water characteristic curve (SWCC), determining equilibrium at various pressures is challenging. This study establishes a methodological framework to identify appropriate experimental duration at each pressure step for the construction of SWCCs via
Plasma ghrelin levels during exercise - effects of intensity and duration.
Erdmann, Johannes; Tahbaz, Rana; Lippl, Florian; Wagenpfeil, Stefan; Schusdziarra, Volker
2007-10-04
Ghrelin, a recently discovered hormone of gastric origin has been shown to stimulate appetite and food intake. In man it is considered to play a role in energy homeostasis and regulation of somatropic function. As exercise affects hunger/satiety sensations and food intake, at least under some experimental conditions, we investigated the effect of exercise intensity and duration on ghrelin release and subsequent ad libitum food intake in normal weight subjects. Bicycle exercise on an ergometer for 30 min at 50 W which was below the aerob-anaerobic threshold led to an increase of ghrelin which remained unchanged during the higher intensity at 100 W. Respective hunger/satiety ratings and subsequent food intake and postprandial ghrelin suppression were identical and not different from controls. In a second group 7 subjects cycled at 50 W for 30, 60 and 120 min, respectively. Ghrelin concentrations rose significantly by 50-70 pg/ml above baseline for the respective period of exercise. While postexercise premeal ghrelin levels were not significantly different subsequent food intake after 120 min of cycling was significantly greater compared to control, 30 min and 60 min exercise, respectively. The present data suggest that low rather than high-intensity exercise stimulates ghrelin levels independent of exercise duration. Stimulation of food intake during prolonged exercise is most likely not due to changes of ghrelin.
DEFF Research Database (Denmark)
Jensen, H I; Ammentorp, J; Ørding, H
2011-01-01
New options for intensive therapy have increased the necessity of considering withholding or withdrawing therapy at intensive care units (ICUs), but the practice varies according to regional and cultural differences. The aim of this study was to investigate the frequency of withholding or withdra...
Azima, Armin; Bödewadt, Jörn; Becker, Oliver; Düsterer, Stefan; Ekanayake, Nagitha; Ivanov, Rosen; Kazemi, Mehdi M.; Lamberto Lazzarino, Leslie; Lechner, Christoph; Maltezopoulos, Theophilos; Manschwetus, Bastian; Miltchev, Velizar; Müller, Jost; Plath, Tim; Przystawik, Andreas; Wieland, Marek; Assmann, Ralph; Hartl, Ingmar; Laarmann, Tim; Rossbach, Jörg; Wurth, Wilfried; Drescher, Markus
2018-01-01
We report on a direct time-domain measurement of the temporal properties of a seeded free-electron laser pulse in the extreme ultraviolet spectral range. Utilizing the oscillating electromagnetic field of terahertz radiation, a single-shot THz streak-camera was applied for measuring the duration as well as spectral phase of the generated intense XUV pulses. The experiment was conducted at FLASH, the free electron laser user facility at DESY in Hamburg, Germany. In contrast to indirect methods, this approach directly resolves and visualizes the frequency chirp of a seeded free-electron laser (FEL) pulse. The reported diagnostic capability is a prerequisite to tailor amplitude, phase and frequency distributions of FEL beams on demand. In particular, it opens up a new window of opportunities for advanced coherent spectroscopic studies making use of the high degree of temporal coherence expected from a seeded FEL pulse.
Effect of grazing frequency and intensity on Lolium perenne L ...
African Journals Online (AJOL)
) system. Low frequency, low intensity grazing produced lower CDMD and herbage N levels than higher grazing frequencies and intensities. These differences were, however, generally small. Overall, levels of herbage digestibility (estimated ...
Classifying low flow hydrological regimes at a regional scale
Directory of Open Access Journals (Sweden)
M. J. Kirkby
2011-12-01
Full Text Available The paper uses a simple water balance model that partitions the precipitation between actual evapotranspiration, quick flow and delayed flow, and has sufficient complexity to capture the essence of climate and vegetation controls on this partitioning. Using this model, monthly flow duration curves have been constructed from climate data across Europe to address the relative frequency of ecologically critical low flow stages in semi-arid rivers, when flow commonly persists only in disconnected pools in the river bed. The hydrological model is based on a dynamic partitioning of precipitation to estimate water available for evapotranspiration and plant growth and for residual runoff. The duration curve for monthly flows has then been analysed to give an estimate of bankfull flow based on recurrence interval. Arguing from observed ratios of cross-sectional areas at flood and low flows, hydraulic geometry suggests that disconnected flow under "pool" conditions is approximately 0.1% of bankfull flow. Flow duration curves define a measure of bankfull discharge on the basis of frequency. The corresponding frequency for pools is then read from the duration curve, using this (0.1% ratio to estimate pool discharge from bank full discharge. The flow duration curve then provides an estimate of the frequency of poorly connected pool conditions, corresponding to this discharge, that constrain survival of river-dwelling arthropods and fish. The methodology has here been applied across Europe at 15 km resolution, and the potential is demonstrated for applying the methodology under alternative climatic scenarios.
A comparison of regional flood frequency analysis approaches in a simulation framework
Ganora, D.; Laio, F.
2016-07-01
Regional frequency analysis (RFA) is a well-established methodology to provide an estimate of the flood frequency curve at ungauged (or scarcely gauged) sites. Different RFA approaches exist, depending on the way the information is transferred to the site of interest, but it is not clear in the literature if a specific method systematically outperforms the others. The aim of this study is to provide a framework wherein carrying out the intercomparison by building up a virtual environment based on synthetically generated data. The considered regional approaches include: (i) a unique regional curve for the whole region; (ii) a multiple-region model where homogeneous subregions are determined through cluster analysis; (iii) a Region-of-Influence model which defines a homogeneous subregion for each site; (iv) a spatially smooth estimation procedure where the parameters of the regional model vary continuously along the space. Virtual environments are generated considering different patterns of heterogeneity, including step change and smooth variations. If the region is heterogeneous, with the parent distribution changing continuously within the region, the spatially smooth regional approach outperforms the others, with overall errors 10-50% lower than the other methods. In the case of a step-change, the spatially smooth and clustering procedures perform similarly if the heterogeneity is moderate, while clustering procedures work better when the step-change is severe. To extend our findings, an extensive sensitivity analysis has been performed to investigate the effect of sample length, number of virtual stations, return period of the predicted quantile, variability of the scale parameter of the parent distribution, number of predictor variables and different parent distribution. Overall, the spatially smooth approach appears as the most robust approach as its performances are more stable across different patterns of heterogeneity, especially when short records are
Future extreme events in European climate: An exploration of regional climate model projections
DEFF Research Database (Denmark)
Beniston, M.; Stephenson, D.B.; Christensen, O.B.
2007-01-01
-90) and future (2071-2 100) climate on the basis of regional climate model simulations produced by the PRUDENCE project. A summary of the main results follows. Heat waves - Regional surface warming causes the frequency, intensity and duration of heat waves to increase over Europe. By the end of the twenty first...
Future projection of design storms using a GCM-informed weather generator
KIm, T. W.; Wi, S.; Valdés-Pineda, R.; Valdés, J. B.
2017-12-01
The rainfall Intensity-Duration-Frequency (IDF) curves are one of the most common tools used to provide planners with a description of the frequency of extreme rainfall events of various intensities and durations. Therefore deriving appropriate IDF estimates is important to avoid malfunctions of water structures that cause huge damage. Evaluating IDF estimates in the context of climate change has become more important because projections from climate models suggest that the frequency of intense rainfall events will increase in the future due to the increase in greenhouse gas emissions. In this study, the Bartlett-Lewis (BL) stochastic rainfall model is employed to generate annual maximum series of various sub-daily durations for test basins of the Model Parameter Estimation Experiment (MOPEX) project, and to derive the IDF curves in the context of climate changes projected by the North American Regional Climate Change (NARCCAP) models. From our results, it has been found that the observed annual rainfall maximum series is reasonably represented by the synthetic annual maximum series generated by the BL model. The observed data is perturbed by change factors to incorporate the NARCCAP climate change scenarios into the IDF estimates. The future IDF curves show a significant difference from the historical IDF curves calculated for the period 1968-2000. Overall, the projected IDF curves show an increasing trend over time. The impacts of changes in extreme rainfall on the hydrologic response of the MOPEX basins are also explored. Acknowledgement: This research was supported by a grant [MPSS-NH-2015-79] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.
Directory of Open Access Journals (Sweden)
Jimeno-Serrano Francisco J
2009-12-01
Full Text Available Abstract Background Evidence suggests that to facilitate physical activity sedentary people may adhere to one component of exercise prescriptions (intensity, duration or frequency without adhering to other components. Some experts have provided evidence for determinants of adherence to different components among healthy people. However, our understanding remains scarce in this area for patients with neck or low back pain. The aims of this study are to determine whether patients with neck or low back pain have different rates of adherence to exercise components of frequency per week and duration per session when prescribed with a home exercise program, and to identify if adherence to both exercise components have distinct predictive factors. Methods A cohort of one hundred eighty-four patients with chronic neck or low back pain who attended physiotherapy in eight primary care centers were studied prospectively one month after intervention. The study had three measurement periods: at baseline (measuring characteristics of patients and pain, at the end of physiotherapy intervention (measuring characteristics of the home exercise program and a month later (measuring professional behaviors during clinical encounters, environmental factors and self-efficacy, and adherence behavior. Results Adherence to duration per session (70.9% ± 7.1 was more probable than adherence to frequency per week (60.7% ± 7.0. Self-efficacy was a relevant factor for both exercise components (p Conclusion We have shown in a clinic-based study that adherence to exercise prescription frequency and duration components have distinct levels and predictive factors. We recommend additional study, and advise that differential attention be given in clinical practice to each exercise component for improving adherence.
International Nuclear Information System (INIS)
Gong, Shaoyan; Ogura, Kazuo; Yambe, Kiyoyuki; Nomizu, Shintaro; Shirai, Akihiro; Yamazaki, Kosuke; Kawamura, Jun; Miura, Takuro; Takanashi, Sho; San, Min Thu
2015-01-01
Periodical corrugations structured on a cylindrical conductor have cylindrical surface waves (CSWs), which are reflected at the corrugation ends and form a CSW-resonator. In this paper, intense radiations in terahertz region based on the CSW-resonator are reported. The CSW-resonators with upper cut off frequencies in the modern IEEE G-band (110–300 GHz) are excited by a coaxially injected annular beam in a weakly relativistic region less than 100 kV. It is shown that there exists an oscillation starting energy for the CSW-resonator. Above the starting energy, very intense terahertz radiations on the order of kW are obtained. The operation frequencies in the range of 166–173 GHz and 182–200 GHz are obtained using two types of CSW-resonator with the different corrugation amplitude. Electromagnetic properties of the CSW-resonator can be controlled by the artificial structure and may play an important role in high-intensity terahertz generations and applications
ANALYSIS OF PROJECTED FREQUENCY AND INTENSITY CHANGES OF PRECIPITATION IN THE CARPATHIAN REGION
Directory of Open Access Journals (Sweden)
KIS ANNA
2015-03-01
Full Text Available Precipitation is the major atmospheric source of surface water, thus, in order to build appropriate adaptation strategies for various economic sections related to water resources it is essential to provide projections for precipitation tendencies as exact as possible. Extreme precipitation events are especially important from this point of view since they may result in different environmental, economical, and/or even human health damages. Excessive precipitation for instance may induce floods, flash-floods, landslides, traffic accidents. On the other hand, lack of precipitation is not favorable either: long dry periods affect agricultural production quite negatively, and hence, food safety can be threatened. Several precipitation-related indices (i.e., describing drought or intensity, exceeding different percentile-based or absolute threshold values are analyzed for the Carpathian region for 1961–2100. For this purpose 11 completed regional climate model simulations are used from the ENSEMBLES database. Before the thorough analysis, a percentile-based bias correction method was applied to the raw data, for which the homogenized daily gridded CarpatClim database (1961–2010 served as a reference. Absolute and relative seasonal mean changes of climate indices are calculated for two future time periods (2021–2050 and 2071–2100 and for three subregions within the entire Carpathian region, namely, for Slovakia, Hungary and Romania. According to our results, longer dry periods are estimated for the summer season, mainly in the southern parts of the domain, while precipitation intensity is likely to increase. Heavy precipitation days and high percentile values are projected to increase, especially, in winter and autumn.
Moore, B C; Peters, R W; Glasberg, B R
1999-12-01
Psychometric functions for detecting increments or decrements in level of sinusoidal pedestals were measured for increment and decrement durations of 5, 10, 20, 50, 100, and 200 ms and for frequencies of 250, 1000, and 4000 Hz. The sinusoids were presented in background noise intended to mask spectral splatter. A three-interval, three-alternative procedure was used. The results indicated that, for increments, the detectability index d' was approximately proportional to delta I/I. For decrements, d' was approximately proportional to delta L. The slopes of the psychometric functions increased (indicating better performance) with increasing frequency for both increments and decrements. For increments, the slopes increased with increasing increment duration up to 200 ms at 250 and 1000 Hz, but at 4000 Hz they increased only up to 50 ms. For decrements, the slopes increased for durations up to 50 ms, and then remained roughly constant, for all frequencies. For a center frequency of 250 Hz, the slopes of the psychometric functions for increment detection increased with duration more rapidly than predicted by a "multiple-looks" hypothesis, i.e., more rapidly than the square root of duration, for durations up to 50 ms. For center frequencies of 1000 and 4000 Hz, the slopes increased less rapidly than predicted by a multiple-looks hypothesis, for durations greater than about 20 ms. The slopes of the psychometric functions for decrement detection increased with decrement duration at a rate slightly greater than the square root of duration, for durations up to 50 ms, at all three frequencies. For greater durations, the increase in slope was less than proportional to the square root of duration. The results were analyzed using a model incorporating a simulated auditory filter, a compressive nonlinearity, a sliding temporal integrator, and a decision device based on a template mechanism. The model took into account the effects of both the external noise and an assumed internal
Directory of Open Access Journals (Sweden)
Anongrit Kangrang
2018-01-01
Full Text Available Optimal rule curves are necessary guidelines in the reservoir operation that have been used to assess performance of any reservoir to satisfy water supply, irrigation, industrial, hydropower, and environmental conservation requirements. This study applied the conditional genetic algorithm (CGA and the conditional tabu search algorithm (CTSA technique to connect with the reservoir simulation model in order to search optimal reservoir rule curves. The Ubolrat Reservoir located in the northeast region of Thailand was an illustrative application including historic monthly inflow, future inflow generated by the SWAT hydrological model using 50-year future climate data from the PRECIS regional climate model in case of B2 emission scenario by IPCC SRES, water demand, hydrologic data, and physical reservoir data. The future and synthetic inflow data of reservoirs were used to simulate reservoir system for evaluating water situation. The situations of water shortage and excess water were shown in terms of frequency magnitude and duration. The results have shown that the optimal rule curves from CGA and CTSA connected with the simulation model can mitigate drought and flood situations than the existing rule curves. The optimal future rule curves were more suitable for future situations than the other rule curves.
Reciprocity of Intensity and Duration on the Dark Adaptation Effects of Light Pulses
National Research Council Canada - National Science Library
Kosnik, William
2002-01-01
...? These questions were addressed to refine the AFRL/HEDO flashblindness model. These studies show that reciprocity between duration and intensity is the exception rather than the rule for dark adaptation...
Voice Range Profiles of Singing Students: The Effects of Training Duration and Institution.
Lycke, Hugo; Siupsinskiene, Nora
2016-01-01
The aim of the study was to assess differences in voice parameters measured by the physiological voice range profile (VRP) in groups of vocally healthy subjects differentiated by the duration of vocal training and the training institution. Six basic frequency- and intensity-related VRP parameters and the frequency dip of the register transition zone were determined from VRP recordings of 162 females studying in individual singing lessons (1st-5th level) in Dutch, Belgian, English, and French public or private training facilities. Sixty-seven nonsinging female students served as controls. Singing students in more advanced singing classes demonstrated a significantly greater frequency range, particularly at high frequencies, than did first-year students. Students with private training showed a significantly increased mean intensity range in comparison to those in group classes, while students with musical theater training exhibited significantly increased frequency- and intensity-related VRP parameters in comparison to the students with classical training. When compared to nonsingers, all singing student subgroups showed significant increases in all basic VRP parameters. However, the register transition parameter was not influenced by training duration or institution. Our study suggests that the extension of physiological vocal limits might depend on training duration and institution. © 2016 S. Karger AG, Basel.
Directory of Open Access Journals (Sweden)
Michal Fusek
2016-11-01
Full Text Available Precipitation records from six stations of the Czech Hydrometeorological Institute were subject to statistical analysis with the objectives of updating the intensity–duration–frequency (IDF curves, by applying extreme value distributions, and comparing the updated curves against those produced by an empirical procedure in 1958. Another objective was to investigate differences between both sets of curves, which could be explained by such factors as different measuring instruments, measuring stations altitudes and data analysis methods. It has been shown that the differences between the two sets of IDF curves are significantly influenced by the chosen method of data analysis.
Trappe, Todd
2012-07-01
On-orbit and ground-based microgravity simulation studies have provided a wealth of information regarding the efficacy of exercise countermeasures for protecting skeletal muscle and cardiovascular function during long-duration spaceflights. While it appears that exercise will be the central component to maintaining skeletal muscle and cardiovascular health of astronauts, the current exercise prescription is not completely effective and is time consuming. This lecture will focus on recent exercise physiology studies examining high intensity, low volume exercise in relation to muscle specific and cardiovascular health. These studies provide the basis of the next generation exercise prescription currently being implemented during long-duration space missions on the International Space Station.
Directory of Open Access Journals (Sweden)
Ernest Greene
2013-12-01
Full Text Available For more than a century researchers have been reporting that the visual impact of a very brief flash is determined by the quantity of photons that the flash delivers. This has been variously described as the Bunsen-Roscoe Law or Bloch's Law, often specified as reciprocity of intensity × duration. Prior research found no evidence for such reciprocity when microsecond-duration flashes from a light-emitting diode array were used to display the major contours of nameable shapes. The present work tested with flash durations ranging up to 100 ms and also found no reciprocity. This departure from classic principles might be due to the specific range of wavelengths of the light-emitting diodes and to a mesopic level of ambient light, which together would preclude activation of rods. The reciprocity of intensity and duration may only be valid with full dark adaptation and very dim flashes that activate rods.
Li, Xin; Babovic, Vladan
2017-04-01
Observed studies on inter-annual variation of precipitation provide insight into the response of precipitation to anthropogenic climate change and natural climate variability. Inter-annual variation of precipitation results from the concurrent variations of precipitation frequency and intensity, understanding of the relative importance of frequency and intensity in the variability of precipitation can help fathom its changing properties. Investigation of the long-term changes of precipitation schemes has been extensively carried out in many regions across the world, however, detailed studies of the relative importance of precipitation frequency and intensity in inter-annual variation of precipitation are still limited, especially in the tropics. Therefore, this study presents a comprehensive framework to investigate the inter-annual variation of precipitation and the dominance of precipitation frequency and intensity in a tropical urban city-state, Singapore, based on long-term (1980-2013) daily precipitation series from 22 rain gauges. First, an iterative Mann-Kendall trend test method is applied to detect long-term trends in precipitation total, frequency and intensity at both annual and seasonal time scales. Then, the relative importance of precipitation frequency and intensity in inducing the inter-annual variation of wet-day precipitation total is analyzed using a dominance analysis method based on linear regression. The results show statistically significant upward trends in wet-day precipitation total, frequency and intensity at annual time scale, however, these trends are not evident during the monsoon seasons. The inter-annual variation of wet-day precipitation is mainly dominated by precipitation intensity for most of the stations at annual time scale and during the Northeast monsoon season. However, during the Southwest monsoon season, the inter-annual variation of wet-day precipitation is mainly dominated by precipitation frequency. These results have
Sensitivity of the probability of failure to probability of detection curve regions
International Nuclear Information System (INIS)
Garza, J.; Millwater, H.
2016-01-01
Non-destructive inspection (NDI) techniques have been shown to play a vital role in fracture control plans, structural health monitoring, and ensuring availability and reliability of piping, pressure vessels, mechanical and aerospace equipment. Probabilistic fatigue simulations are often used in order to determine the efficacy of an inspection procedure with the NDI method modeled as a probability of detection (POD) curve. These simulations can be used to determine the most advantageous NDI method for a given application. As an aid to this process, a first order sensitivity method of the probability-of-failure (POF) with respect to regions of the POD curve (lower tail, middle region, right tail) is developed and presented here. The sensitivity method computes the partial derivative of the POF with respect to a change in each region of a POD or multiple POD curves. The sensitivities are computed at no cost by reusing the samples from an existing Monte Carlo (MC) analysis. A numerical example is presented considering single and multiple inspections. - Highlights: • Sensitivities of probability-of-failure to a region of probability-of-detection curve. • The sensitivities are computed with negligible cost. • Sensitivities identify the important region of a POD curve. • Sensitivities can be used as a guide to selecting the optimal POD curve.
Duration and intensity of physical activity and disability among European elderly men
van den Brink, Carolien L.; Picavet, Hsusanj; van den Bos, Geertrudis A. M.; Giampaoli, Simona; Nissinen, Aulikki; Kromhout, Daan
2005-01-01
Purpose. To investigate the relationship between duration and intensity of physical activity and disability 10 years later, and to investigate the possible effect of selective mortality. Method. Longitudinal data of 560 men aged 70 - 89 years, without disability at baseline from the Finland, Italy
Maternal Habitual Midday Napping Duration and Frequency are Associated with High Birthweight.
Zheng, Xiaoxuan; Zhang, Lina; Shen, Lijun; Song, Lulu; Li, Hui; Liu, Bingqing; Li, Yuanyuan; Xia, Wei; Zhang, Bin; Xu, Shunqing; Wang, Youjie
2017-09-05
Habitual midday napping is a common habit in China, especially for pregnant women. The purpose of this study was to examine whether duration and frequency of maternal habitual midday napping were associated with high birthweight (HBW). A total of 10,482 participants from Healthy Baby Cohort were include in our analysis. The information of the mothers and their infants were abstracted from medical records, or obtained from questionnaire. Logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of habitual midday napping duration and frequency with HBW. Of the participants, 8,705 (83.0%) reported having habitual midday napping. Duration and frequency of napping had a positive association with HBW without adjustment. After controlling for potential confounders, increasing risk of HBW was observed in participants who napped 1.5-2 hours (OR, 1.50, 95% CI, 1.14, 1.98), and ≥2 hours (OR, 1.35, 95% CI, 1.03, 1.78) compared with no habitual midday napping. Participants who took naps ≥5 days/week had a higher risk of HBW (OR, 1.37, 95% CI, 1.07, 1.77) compared with the women without naps. This suggests that longer (≥1.5 hours) and more frequent (≥5 days/week) maternal habitual midday napping were associated with an increased risk of HBW.
Lind, Greg D.; Stonewall, Adam J.
2018-02-13
In this study, “naturalized” daily streamflow records, created by the U.S. Army Corps of Engineers and the Bureau of Reclamation, were used to compute 1-, 3-, 7-, 10-, 15-, 30-, and 60-day annual maximum streamflow durations, which are running averages of daily streamflow for the number of days in each duration. Once the annual maximum durations were computed, the floodduration frequencies could be estimated. The estimated flood-duration frequencies correspond to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent probabilities of their occurring or being exceeded each year. For this report, the focus was on the Willamette River Basin in Oregon, which is a subbasin of the Columbia River Basin. This study is part of a larger one encompassing the entire Columbia Basin.
International Nuclear Information System (INIS)
Krakover, Naftaly; Krylov, Slava; Ilic, B Robert
2016-01-01
The ability to control nonlinear interactions of suspended mechanical structures offers a unique opportunity to engineer rich dynamical behavior that extends the dynamic range and ultimate device sensitivity. We demonstrate a displacement sensing technique based on resonant frequency monitoring of curved, doubly clamped, bistable micromechanical beams interacting with a movable electrode. In this configuration, the electrode displacement influences the nonlinear electrostatic interactions, effective stiffness and frequency of the curved beam. Increased sensitivity is made possible by dynamically operating the beam near the snap-through bistability onset. Various in-plane device architectures were fabricated from single crystal silicon and measured under ambient conditions using laser Doppler vibrometry. In agreement with the reduced order Galerkin-based model predictions, our experimental results show a significant resonant frequency reduction near critical snap-through, followed by a frequency increase within the post-buckling configuration. Interactions with a stationary electrode yield a voltage sensitivity up to ≈560 Hz V −1 and results with a movable electrode allow motion sensitivity up to ≈1.5 Hz nm −1 . Our theoretical and experimental results collectively reveal the potential of displacement sensing using nonlinear interactions of geometrically curved beams near instabilities, with possible applications ranging from highly sensitive resonant inertial detectors to complex optomechanical platforms providing an interface between the classical and quantum domains. (paper)
Directory of Open Access Journals (Sweden)
M. Sivapalan
2012-11-01
Full Text Available The paper reports on a four-pronged study of the physical controls on regional patterns of the flow duration curve (FDC. This involved a comparative analysis of long-term continuous data from nearly 200 catchments around the US, encompassing a wide range of climates, geology, and ecology. The analysis was done from three different perspectives – statistical analysis, process-based modeling, and data-based classification – followed by a synthesis, which is the focus of this paper. Streamflow data were separated into fast and slow flow responses, and associated signatures, and both total flow and its components were analyzed to generate patterns. Regional patterns emerged in all aspects of the study. The mixed gamma distribution described well the shape of the FDC; regression analysis indicated that certain climate and catchment properties were first-order controls on the shape of the FDC. In order to understand the spatial patterns revealed by the statistical study, and guided by the hypothesis that the middle portion of the FDC is a function of the regime curve (RC, mean within-year variation of flow, we set out to classify these catchments, both empirically and through process-based modeling, in terms of their regime behavior. The classification analysis showed that climate seasonality and aridity, either directly (empirical classes or through phenology (vegetation processes, were the dominant controls on the RC. Quantitative synthesis of these results determined that these classes were indeed related to the FDC through its slope and related statistical parameters. Qualitative synthesis revealed much diversity in the shapes of the FDCs even within each climate-based homogeneous class, especially in the low-flow tails, suggesting that catchment properties may have become the dominant controls. Thus, while the middle portion of the FDC contains the average response of the catchment, and is mainly controlled by climate, the tails of the FDC
Birth weight curves tailored to maternal world region.
Ray, Joel G; Sgro, Michael; Mamdani, Muhammad M; Glazier, Richard H; Bocking, Alan; Hilliard, Robert; Urquia, Marcelo L
2012-02-01
Newborns of certain immigrant mothers are smaller at birth than those of domestically born mothers. Contemporary, population-derived percentile curves for these newborns are lacking, as are estimates of their risk of being misclassified as too small or too large using conventional rather than tailored birth weight curves. We completed a population-based study of 766 688 singleton live births in Ontario from 2002 to 2007. Smoothed birth weight percentile curves were generated for males and females, categorized by maternal world region of birth: Canada (63.5%), Europe/Western nations (7.6%), Africa/Caribbean (4.9%), Middle East/North Africa (3.4%), Latin America (3.4%), East Asia/Pacific (8.1%), and South Asia (9.2%). We determined the likelihood of misclassifying an infant as small for gestational age (≤ 10th percentile for weight) or as large for gestational age (≥ 90th percentile for weight) on a Canadian-born maternal curve versus one specific to maternal world region of origin. Significantly lower birth weights were seen at gestation-specific 10th, 50th, and 90th percentiles among term infants born to mothers from each world region, with the exception of Europe/Western nations, compared with those for infants of Canadian-born mothers. For example, for South Asian babies born at 40 weeks' gestation, the absolute difference at the 10th percentile was 198 g (95% CI 183 to 212) for males and 170 g (95% CI 161 to 179) for females. Controlling for maternal age and parity, South Asian males had an odds ratio of 2.60 (95% CI 2.53 to 2.68) of being misclassified as small for gestational age, equivalent to approximately 116 in 1000 newborns; for South Asian females the OR was 2.41 (95% CI 2.34 to 2.48), equivalent to approximately 106 per 1000 newborns. Large for gestational age would be missed in approximately 61 per 1000 male and 57 per 1000 female South Asian newborns if conventional rather than ethnicity-specific birth weight curves were used. Birth weight curves
Directory of Open Access Journals (Sweden)
Vero Sara E.
2016-12-01
Full Text Available During laboratory assessment of the soil water characteristic curve (SWCC, determining equilibrium at various pressures is challenging. This study establishes a methodological framework to identify appropriate experimental duration at each pressure step for the construction of SWCCs via centrifugation. Three common temporal approaches to equilibrium – 24-, 48- and 72-h – are examined, for a grassland and arable soil. The framework highlights the differences in equilibrium duration between the two soils. For both soils, the 24-h treatment significantly overestimated saturation. For the arable site, no significant difference was observed between the 48- and 72-h treatments. Hence, a 48-h treatment was sufficient to determine ‘effective equilibrium’. For the grassland site, the 48- and 72-h treatments differed significantly. This highlights that a more prolonged duration is necessary for some soils to conclusively determine that effective equilibrium has been reached. This framework can be applied to other soils to determine the optimum centrifuge durations for SWCC construction.
Flood Frequency Analysis For Partial Duration Series In Ganjiang River Basin
zhangli, Sun; xiufang, Zhu; yaozhong, Pan
2016-04-01
Accurate estimation of flood frequency is key to effective, nationwide flood damage abatement programs. The partial duration series (PDS) method is widely used in hydrologic studies because it considers all events above a certain threshold level as compared to the annual maximum series (AMS) method, which considers only the annual maximum value. However, the PDS has a drawback in that it is difficult to define the thresholds and maintain an independent and identical distribution of the partial duration time series; this drawback is discussed in this paper. The Ganjiang River is the seventh largest tributary of the Yangtze River, the longest river in China. The Ganjiang River covers a drainage area of 81,258 km2 at the Wanzhou hydrologic station as the basin outlet. In this work, 56 years of daily flow data (1954-2009) from the Wanzhou station were used to analyze flood frequency, and the Pearson-III model was employed as the hydrologic probability distribution. Generally, three tasks were accomplished: (1) the threshold of PDS by percentile rank of daily runoff was obtained; (2) trend analysis of the flow series was conducted using PDS; and (3) flood frequency analysis was conducted for partial duration flow series. The results showed a slight upward trend of the annual runoff in the Ganjiang River basin. The maximum flow with a 0.01 exceedance probability (corresponding to a 100-year flood peak under stationary conditions) was 20,000 m3/s, while that with a 0.1 exceedance probability was 15,000 m3/s. These results will serve as a guide to hydrological engineering planning, design, and management for policymakers and decision makers associated with hydrology.
A comprehensive continent-wide regionalisation investigation for daily design rainfall
F. Johnson; J. Green
2018-01-01
Study region: Australia. Study focus: Design rainfalls, in the form of Intensity Duration Frequency curves, are the standard input for most flood studies. Methods to combine rainfall data across space are required to provide optimal estimates of design rainfalls and constrain their uncertainty. This paper robustly investigates the use of a variety of regionalization methods to provide Australia wide design rainfall estimates using 8619 high quality rainfall stations. The influence of an indiv...
Effects of pulse duration on magnetostimulation thresholds
Energy Technology Data Exchange (ETDEWEB)
Saritas, Emine U., E-mail: saritas@ee.bilkent.edu.tr [Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720-1762 (United States); Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, Ankara 06800 (Turkey); National Magnetic Resonance Research Center (UMRAM), Bilkent University, Bilkent, Ankara 06800 (Turkey); Goodwill, Patrick W. [Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720-1762 (United States); Conolly, Steven M. [Department of Bioengineering, University of California, Berkeley, Berkeley, California 94720-1762 (United States); Department of EECS, University of California, Berkeley, California 94720-1762 (United States)
2015-06-15
. Results: The magnetostimulation limits decreased with increasing pulse duration (T{sub pulse}). For T{sub pulse} < 18 ms, the thresholds were significantly higher than at the longest pulse durations (p < 0.01, paired Wilcoxon signed-rank test). The normalized magnetostimulation threshold (B{sub Norm}) vs duration curve at all three frequencies agreed almost identically, indicating that the observed effect is independent of the operating frequency. At the shortest pulse duration (T{sub pulse} ≈ 2 ms), the thresholds were approximately 24% higher than at the asymptotes. The thresholds decreased to within 4% of their asymptotic values for T{sub pulse} > 20 ms. These trends were well characterized (R{sup 2} = 0.78) by a stretched exponential function given by B{sub Norm}=1+αe{sup −(T{sub p}{sub u}{sub l}{sub s}{sub e}/β){sup γ}}, where the fitted parameters were α = 0.44, β = 4.32, and γ = 0.60. Conclusions: This work shows for the first time that the magnetostimulation thresholds decrease with increasing pulse duration, and that this effect is independent of the operating frequency. Normalized threshold vs duration trends are almost identical for a 20-fold range of frequencies: the thresholds are significantly higher at short pulse durations and settle to within 4% of their asymptotic values for durations longer than 20 ms. These results emphasize the importance of matching the human-subject experiments to the imaging conditions of a particular setup. Knowing the dependence of the safety limits to all contributing factors is critical for increasing the time-efficiency of imaging systems that utilize time-varying magnetic fields.
Effects of pulse duration on magnetostimulation thresholds
International Nuclear Information System (INIS)
Saritas, Emine U.; Goodwill, Patrick W.; Conolly, Steven M.
2015-01-01
. Results: The magnetostimulation limits decreased with increasing pulse duration (T pulse ). For T pulse < 18 ms, the thresholds were significantly higher than at the longest pulse durations (p < 0.01, paired Wilcoxon signed-rank test). The normalized magnetostimulation threshold (B Norm ) vs duration curve at all three frequencies agreed almost identically, indicating that the observed effect is independent of the operating frequency. At the shortest pulse duration (T pulse ≈ 2 ms), the thresholds were approximately 24% higher than at the asymptotes. The thresholds decreased to within 4% of their asymptotic values for T pulse > 20 ms. These trends were well characterized (R 2 = 0.78) by a stretched exponential function given by B Norm =1+αe −(T pulse /β) γ , where the fitted parameters were α = 0.44, β = 4.32, and γ = 0.60. Conclusions: This work shows for the first time that the magnetostimulation thresholds decrease with increasing pulse duration, and that this effect is independent of the operating frequency. Normalized threshold vs duration trends are almost identical for a 20-fold range of frequencies: the thresholds are significantly higher at short pulse durations and settle to within 4% of their asymptotic values for durations longer than 20 ms. These results emphasize the importance of matching the human-subject experiments to the imaging conditions of a particular setup. Knowing the dependence of the safety limits to all contributing factors is critical for increasing the time-efficiency of imaging systems that utilize time-varying magnetic fields
Masoudifar, Mehrdad; Aghadavoudi, Omid; Adib, Sajjad
2016-01-01
Postdural puncture headache (PDPH) is a relatively common complication after regional anesthesia, especially in younger people, bothersome to patients and needs prophylaxis to prevent this complication. This study was conducted aiming to determine the preventive effect of dexamethasone plus caffeine and acetaminophen on relative frequency and intensity of PDPH after spinal anesthesia. In a clinical trial study, 90 candidates for the lower extremities orthopedic elective operation were divided into two groups of 45 individuals each. Intervention group received the compound of 500 mg acetaminophen +65 mg oral caffeine +8 mg venous dexamethasone an hour before spinal blocking, and the control group received placebo tablets + a dexamethasone equivalent volume of venous normal saline. The level of postoperative headache at the time of entrance to recovery and discharge, 6, 12, 24, 48, and 72 h postoperatively were measured based on Visual Analog Scale criterion in the two groups and then compared with each other. During the study, 24 patients in the control group and 17 patients in the intervention group were afflicted with headache; however, with no significant difference (P = 0.14). Total frequency of headache incidence was 35 times in the control group and 27 times in the intervention group (P = 0.32). Though the taking of acetaminophen + caffeine + dexamethasone is associated with a decrease in headache intensity and duration and decrease in PDPH incidence, compared with placebo, however, no essentially and statistically significant effect was produced.
Skeer, Margie R; Yantsides, Konstantina E; Eliasziw, Misha; Tracy, Migdalia R; Carlton-Smith, Allison R; Spirito, Anthony
2016-01-01
Children who frequently eat family meals are less likely to develop risk- and behavior-related outcomes, such as substance misuse, sexual risk, and obesity. Few studies have examined sociodemographic characteristics associated with both meal frequency (i.e., number of meals) and duration (i.e., number of minutes spent at mealtimes). We examine the association between sociodemographics and family meal frequency and duration among a sample of 85 parents in a large New England city that was recruited through the public-school system. Additionally, we examined differences in family meals by race/ethnicity and parental nativity. Unadjusted ANOVA and adjusted ANCOVA models were used to assess the associations between sociodemographic characteristics and frequency and duration of meals. Sociodemographic characteristics were not significantly associated with the frequency of family meals; however, in the adjusted models, differences were associated with duration of meals. Parents who were born outside the U.S. spent an average of 135.0 min eating meals per day with their children compared to 76.2 for parents who were born in the U.S. ( p meals (126.7 min) compared to parents who reported being married or partnered (84.4; p = 0.02). Differences existed in meal duration by parental nativity and race/ethnicity, ranging from 63.7 min among multi-racial/other parents born in the U.S. to 182.8 min among black parents born outside the U.S. This study builds a foundation for focused research into the mechanisms of family meals. Future longitudinal epidemiologic research on family meals may help to delineate targets for prevention of maladaptive behaviors, which could affect family-based practices, interventions, and policies.
Energy Technology Data Exchange (ETDEWEB)
Venkatachalam, P.; Paul, S.F.D.; Mohankumar, M.N.; Prabhu, B.K.; Gajendiran, N.; Jeevanram, R.K
2000-07-01
A translocation dose-response curve using a single pair of painted chromosomes was constructed. The translocation frequencies observed at different doses were compared to those obtained for dicentrics (DC) and micronuclei (MN). The translocation and DC frequency followed the Poisson distribution and MN showed over-dispersion. The translocation and DC frequencies were nearly the same for each dose point. Micronuclei showed a comparatively lower frequency. The alpha/beta ratio for translocations (0.916) and DC (0.974) were comparable, whereas the value for MN (1.526) was much higher. The equal frequencies of translocations and DC observed for a given dose indicated that genomic translocation frequency estimated using a single pair of painted chromosomes provides a reliable and easy method to measure translocation frequency. (autho000.
International Nuclear Information System (INIS)
Venkatachalam, P.; Paul, S.F.D.; Mohankumar, M.N.; Prabhu, B.K.; Gajendiran, N.; Jeevanram, R.K.
2000-01-01
A translocation dose-response curve using a single pair of painted chromosomes was constructed. The translocation frequencies observed at different doses were compared to those obtained for dicentrics (DC) and micronuclei (MN). The translocation and DC frequency followed the Poisson distribution and MN showed over-dispersion. The translocation and DC frequencies were nearly the same for each dose point. Micronuclei showed a comparatively lower frequency. The alpha/beta ratio for translocations (0.916) and DC (0.974) were comparable, whereas the value for MN (1.526) was much higher. The equal frequencies of translocations and DC observed for a given dose indicated that genomic translocation frequency estimated using a single pair of painted chromosomes provides a reliable and easy method to measure translocation frequency. (author)
Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men.
Broom, David R; Miyashita, Masashi; Wasse, Lucy K; Pulsford, Richard; King, James A; Thackray, Alice E; Stensel, David J
2017-03-01
Acute exercise transiently suppresses the orexigenic gut hormone acylated ghrelin, but the extent to which exercise intensity and duration determine this response is not fully understood. The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were examined in two experiments. In experiment one, nine healthy males completed three, 4-h conditions (control, moderate-intensity running (MOD) and vigorous-intensity running (VIG)), with an energy expenditure of ~2.5 MJ induced in both MOD (55-min running at 52% peak oxygen uptake (V.O 2peak )) and VIG (36-min running at 75% V.O 2peak ). In experiment two, nine healthy males completed three, 9-h conditions (control, 45-min running (EX45) and 90-min running (EX90)). Exercise was performed at 70% V.O 2peak In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were quantified at predetermined intervals. In experiment one, delta acylated ghrelin concentrations were lower than control in MOD (ES = 0.44, P = 0.01) and VIG (ES = 0.98, P Hunger ratings were similar across the conditions (P = 0.35). In experiment two, delta acylated ghrelin concentrations were lower than control in EX45 (ES = 0.77, P Hunger ratings were lower than control in EX45 (ES = 0.20, P = 0.01) and EX90 (ES = 0.27, P = 0.001); EX45 and EX90 were similar (ES = 0.07, P = 0.34). Hunger and delta acylated ghrelin concentrations remained suppressed at 1.5 h in EX90 but not EX45. In conclusion, exercise intensity, and to a lesser extent duration, are determinants of the acylated ghrelin response to acute exercise. © 2017 Society for Endocrinology.
International Nuclear Information System (INIS)
Okano, Yasushi; Yamano, Hidemasa
2016-01-01
A method to obtain a hazard curve of a forest fire was developed. The method has four steps: a logic tree formulation, a response surface evaluation, a Monte Carlo simulation, and an annual exceedance frequency calculation. The logic tree consists domains of 'forest fire breakout and spread conditions', 'weather conditions', 'vegetation conditions', and 'forest fire simulation conditions.' Condition parameters of the logic boxes are static if stable during a forest fire or not sensitive to a forest fire intensity, and non-static parameters are variables whose frequency/probability is given based on existing databases or evaluations. Response surfaces of a reaction intensity and a fireline intensity were prepared by interpolating outputs from a number of forest fire propagation simulations by fire area simulator (FARSITE). The Monte Carlo simulation was performed where one sample represented a set of variable parameters of the logic boxes and a corresponding intensity was evaluated from the response surface. The hazard curve, i.e. an annual exceedance frequency of the intensity, was therefore calculated from the histogram of the Monte Carlo simulation outputs. The new method was applied to evaluate hazard curves of a reaction intensity and a fireline intensity for a typical location around a sodium-cooled fast reactor in Japan. (author)
Energy Technology Data Exchange (ETDEWEB)
Lazzati, Davide [Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, OR 97331 (United States)
2016-10-01
We present MCRaT, a Monte Carlo Radiation Transfer code for self-consistently computing the light curves and spectra of the photospheric emission from relativistic, unmagnetized jets. We apply MCRaT to a relativistic hydrodynamic simulation of a long-duration gamma-ray burst jet, and present the resulting light curves and time-dependent spectra for observers at various angles from the jet axis. We compare our results to observational results and find that photospheric emission is a viable model to explain the prompt phase of long-duration gamma-ray bursts at the peak frequency and above, but faces challenges when reproducing the flat spectrum below the peak frequency. We finally discuss possible limitations of these results both in terms of the hydrodynamics and the radiation transfer and how these limitations could affect the conclusions that we present.
Duration and frequency of every day activities in total hip patients.
Morlock, M; Schneider, E; Bluhm, A; Vollmer, M; Bergmann, G; Müller, V; Honl, M
2001-07-01
Little knowledge about frequency and duration of daily activities in patients after total hip arthroplasty is available. Such information is required for the definition of realistic load collectives for pre-clinical testing of prostheses. It could also be helpful for the quantitative evaluation of surgery outcome with different prosthesis types. The purpose of this study was to develop and apply a system for the determination of frequency and duration of patient activities in their habitual environment and to compare the results to a clinical outcome score (Harris hip score).A portable activity monitoring system (weight 1.6 kg including batteries) was designed using a Palm top computer, 2 inclination sensors for the thigh and calf and one goniometer positioned at the knee joint. An algorithm was developed to identify frequency and duration of the activities lying, sitting, standing, walking and stair climbing from the signals of the 3 sensors. 42 patients participated in the study and were equipped with the system in the morning at their home. Datasets of 31 patients (age 62.5+/-11.5 y) covered more than 6h (9.8 +/- 1.6 h) and were included in the analysis. Prosthesis specific data as well as the Harris hip score were collected. The most frequent patient activity was sitting (44.3% of the time), followed by standing (24.5%), walking (10.2%), lying (5.8%) and stair climbing (0.4%). The median number of steps/stairs was 6048/164. The number of step cycles representing one year in vivo use should, consequently, be increased to 1.1 million. The Harris hip score (91.4 +/- 9.8) correlated significantly with the number of stairs (r(2) = 0.26, p = 0.003) and showed a positive tendency with the number of steps per day. No differences in activity levels between prosthesis specific factors were found.
Ying Ouyang; Prem B. Parajuli; Daniel A. Marion
2013-01-01
Pollution of surface water with harmful chemicals and eutrophication of rivers and lakes with excess nutrients are serious environmental concerns. This study estimated surface water quality in a stream within the Yazoo River Basin (YRB), Mississippi, USA, using the duration curve and recurrence interval analysis techniques. Data from the US Geological Survey (USGS)...
Entropy Parameter M in Modeling a Flow Duration Curve
Directory of Open Access Journals (Sweden)
Yu Zhang
2017-12-01
Full Text Available A flow duration curve (FDC is widely used for predicting water supply, hydropower, environmental flow, sediment load, and pollutant load. Among different methods of constructing an FDC, the entropy-based method, developed recently, is appealing because of its several desirable characteristics, such as simplicity, flexibility, and statistical basis. This method contains a parameter, called entropy parameter M, which constitutes the basis for constructing the FDC. Since M is related to the ratio of the average streamflow to the maximum streamflow which, in turn, is related to the drainage area, it may be possible to determine M a priori and construct an FDC for ungauged basins. This paper, therefore, analyzed the characteristics of M in both space and time using streamflow data from 73 gauging stations in the Brazos River basin, Texas, USA. Results showed that the M values were impacted by reservoir operation and possibly climate change. The values were fluctuating, but relatively stable, after the operation of the reservoirs. Parameter M was found to change inversely with the ratio of average streamflow to the maximum streamflow. When there was an extreme event, there occurred a jump in the M value. Further, spatially, M had a larger value if the drainage area was small.
Downscaling of Short-Term Precipitation from Regional Climate Models for Sustainable Urban Planning
Directory of Open Access Journals (Sweden)
Holger Hoppe
2012-05-01
Full Text Available A framework for downscaling precipitation from RCM projections to the high resolutions in time and space required in the urban hydrological climate change impact assessment is outlined and demonstrated. The basic approach is that of Delta Change, developed for both continuous and event-based applications. In both cases, Delta Change Factors (DCFs are calculated which represent the expected future change of some key precipitation statistics. In the continuous case, short-term precipitation from climate projections are analysed in order to estimate DCFs associated with different percentiles in the frequency distribution of non-zero intensities. The DCFs may then be applied to an observed time series, producing a realisation of a future time series. The event-based case involves downscaling of Intensity-Duration-Frequency (IDF curves based on extreme value analysis of annual maxima using the Gumbel distribution. The resulting DCFs are expressed as a function of duration and frequency (i.e., return period and may be used to estimate future design storms. The applications are demonstrated in case studies focusing on the expected changes in short-term precipitation statistics until 2100 in the cities of Linz (Austria and Wuppertal (Germany. The downscaling framework is implemented in the climate service developed within the EU-project SUDPLAN.
Directory of Open Access Journals (Sweden)
Vani A Mathur
2016-09-01
Full Text Available Migraine is a pain disorder associated with abnormal brain structure and function, yet the effect of migraine on acute pain processing remains unclear. It also remains unclear whether altered pain-related brain responses and related structural changes are associated with clinical migraine characteristics. Using fMRI and three levels of thermal stimuli (non-painful, mildly painful, and moderately painful, we compared whole-brain activity between 14 migraine patients and 14 matched controls. Although, there were no significant differences in pain thresholds and pre-scan pain ratings to mildly painful thermal stimuli, patients had aberrant suprathreshold nociceptive processing. Compared to controls, patients had reduced activity in pain modulatory regions including left dorsolateral prefrontal, posterior parietal, and middle temporal cortices and, at a lower-threshold, greater activation in the right mid-insula to moderate pain versus mild pain. We also found that pain-related activity in the insula was associated with clinical variables in patients, including associations between: bilateral anterior insula and pain catastrophizing (PCS; bilateral anterior insula and contralateral posterior insula and migraine pain intensity; and bilateral posterior insula and migraine frequency at a lower-threshold. PCS and migraine pain intensity were also negatively associated with activity in midline regions including posterior cingulate and medial prefrontal cortices. Diffusion tensor imaging revealed a negative correlation between fractional anisotropy (a measure of white matter integrity; FA and migraine duration in the right mid-insula and a positive correlation between left mid-insula FA and PCS. In sum, while patients showed lower sensitivity to acute noxious stimuli, the neuroimaging findings suggest enhanced nociceptive processing and significantly disrupted modulatory networks, particularly involving the insula cortex, associated with indices of
WANG, J.
2017-12-01
In stream water quality control, the total maximum daily load (TMDL) program is very effective. However, the load duration curves (LDC) of TMDL are difficult to be established because no sufficient observed flow and pollutant data can be provided in data-scarce watersheds in which no hydrological stations or consecutively long-term hydrological data are available. Although the point sources or a non-point sources of pollutants can be clarified easily with the aid of LDC, where does the pollutant come from and to where it will be transported in the watershed cannot be traced by LDC. To seek out the best management practices (BMPs) of pollutants in a watershed, and to overcome the limitation of LDC, we proposed to develop LDC based on a distributed hydrological model of SWAT for the water quality management in data scarce river basins. In this study, firstly, the distributed hydrological model of SWAT was established with the scarce-hydrological data. Then, the long-term daily flows were generated with the established SWAT model and rainfall data from the adjacent weather station. Flow duration curves (FDC) was then developed with the aid of generated daily flows by SWAT model. Considering the goal of water quality management, LDC curves of different pollutants can be obtained based on the FDC. With the monitored water quality data and the LDC curves, the water quality problems caused by the point or non-point source pollutants in different seasons can be ascertained. Finally, the distributed hydrological model of SWAT was employed again to tracing the spatial distribution and the origination of the pollutants of coming from what kind of agricultural practices and/or other human activities. A case study was conducted in the Jian-jiang river, a tributary of Yangtze river, of Duyun city, Guizhou province. Results indicate that this kind of method can realize the water quality management based on TMDL and find out the suitable BMPs for reducing pollutant in a watershed.
International Nuclear Information System (INIS)
Xiao Yu; Li Can; Xu Shan-Hui; Feng Zhou-Ming; Yang Chang-Sheng; Zhao Qi-Lai; Yang Zhong-Min
2015-01-01
Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20 dB from 0.2 to 5kHz and over 10 dB from 5 to 10 kHz. The relaxation oscillation peak is suppressed by 22 dB. In addition, a long term (24 h) laser instability of less than 0.05% is achieved. (paper)
Energy Technology Data Exchange (ETDEWEB)
Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); McGinnis, Pauline; Alencar, Silvia H. P. [Departamento de Física—ICEx—UFMG, Av. Antônio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Hillenbrand, Lynne A.; Carpenter, John [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Terebey, Susan [Department of Physics and Astronomy, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Morales-Calderón, María [Centro de Astrobiología, Dpto. de Astrofísica, INTA-CSIC, PO BOX 78, E-28691, ESAC Campus, Villanueva de la Cañada, Madrid (Spain); Bouvier, Jerome; Venuti, Laura [Université de Grenoble, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), F-38000 Grenoble (France); CNRS, IPAG, F-38000 Grenoble (France); Hartmann, Lee; Calvet, Nuria [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); Micela, Giusi; Flaccomio, Ettore [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134, Palermo (Italy); Song, Inseok [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602–2451 (United States); Gutermuth, Rob, E-mail: stauffer@ipac.caltech.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); and others
2015-04-15
We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall.
International Nuclear Information System (INIS)
Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean; McGinnis, Pauline; Alencar, Silvia H. P.; Hillenbrand, Lynne A.; Carpenter, John; Turner, Neal J.; Terebey, Susan; Morales-Calderón, María; Bouvier, Jerome; Venuti, Laura; Hartmann, Lee; Calvet, Nuria; Micela, Giusi; Flaccomio, Ettore; Song, Inseok; Gutermuth, Rob
2015-01-01
We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall
Rong, Youying; Ma, Jianhui; Chen, Lingxiao; Liu, Yan; Siyushev, Petr; Wu, Botao; Pan, Haifeng; Jelezko, Fedor; Wu, E.; Zeng, Heping
2018-05-01
We report a method with high time resolution to measure the excited-state lifetime of silicon vacancy centers in bulk diamond avoiding timing jitter from the single-photon detectors. Frequency upconversion of the fluorescence emitted from silicon vacancy centers was achieved from 738 nm to 436 nm via sum frequency generation with a short pump pulse. The excited-state lifetime can be obtained by measuring the intensity of upconverted light while the pump delay changes. As a probe, a pump laser with pulse duration of 11 ps provided a high temporal resolution of the measurement. The lifetime extracted from the pump–probe curve was 0.755 ns, which was comparable to the timing jitter of the single-photon detectors.
Energy Technology Data Exchange (ETDEWEB)
Filer, J.K. (Washington and Lee Univ., Lexington, VA (United States). Dept. of Geology)
1992-01-01
Siliciclastic sequences have been mapped in the subsurface and outcrop of much of the Appalachian basin in facies ranging from shale in the basin plain to shelf sandstone. Eleven transgressive/regressive cycles have been defined in an estimated 1.5 to 2.0 Ma period in the latest Frasnian and earliest Famennian, and range in duration from about 75,000 to 400,000 years. Lithofacies maps, covering most of the basin, were prepared for each sequence. These maps show both the area of basinal black shale deposition, which defines the base of each cycle, and the areal extent of subsequent clinoform siltstone and shelf sandstone deposition in the upper portion of each cycle. The stratigraphic patterns show two stacked sets of progradational basinwide sequences. Geographic scale of the study precludes autocyclic controls of cycles. Sea-level/climate cycles, probably superimposed on longer term tectonic cycles, are the proposed cause of these observed depositional patterns. Removal of the long-term progradational trend of Upper Devonian basin filling results in a proposed eustatic sea-level curve (Johnson and others (1985)) reveals correspondence of three regressive maxima in both models. The curve presented here reveals that an ongoing process of higher frequency sea-level modification was active at this time. Higher frequency sea-level events, nested within previously interpreted lower frequency global events, are inferred to also be eustatic. Models of a biotic crises which occurs at this time should consider the implications of these high frequency sea-level cycles. The patterns observed are consistent with latest Frasnian initiation of glaciation in South America. This would be somewhat earlier than has generally been accepted.
Branstetter, Brian K.; DeLong, Caroline M.; Dziedzic, Brandon; Black, Amy; Bakhtiari, Kimberly
2016-01-01
Bottlenose dolphins (Tursiops truncatus) use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin’s (Tursiops truncatus) ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A) in response to a specific sound (sound A) for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin’s ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin’s acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition. PMID:26863519
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Brian K Branstetter
Full Text Available Bottlenose dolphins (Tursiops truncatus use the frequency contour of whistles produced by conspecifics for individual recognition. Here we tested a bottlenose dolphin's (Tursiops truncatus ability to recognize frequency modulated whistle-like sounds using a three alternative matching-to-sample paradigm. The dolphin was first trained to select a specific object (object A in response to a specific sound (sound A for a total of three object-sound associations. The sounds were then transformed by amplitude, duration, or frequency transposition while still preserving the frequency contour of each sound. For comparison purposes, 30 human participants completed an identical task with the same sounds, objects, and training procedure. The dolphin's ability to correctly match objects to sounds was robust to changes in amplitude with only a minor decrement in performance for short durations. The dolphin failed to recognize sounds that were frequency transposed by plus or minus ½ octaves. Human participants demonstrated robust recognition with all acoustic transformations. The results indicate that this dolphin's acoustic recognition of whistle-like sounds was constrained by absolute pitch. Unlike human speech, which varies considerably in average frequency, signature whistles are relatively stable in frequency, which may have selected for a whistle recognition system invariant to frequency transposition.
Salles, Christian; Chu, Yin; Tournoud, Marie-George; Ou, Mengli; Perrin, Jean-Louis; Cres, François-Noël; Ma, Youhua
2016-04-01
during summer. Using the above methodology the future dynamics of the Fengle River is characterized on discharge-duration-frequency curves. Results will be discussed with regards to the sensitivity of predicted flood occurrence, duration and magnitude by quantifying the impact of rainfall, temperature and land-use changes.
A regional and nonstationary model for partial duration series of extreme rainfall
DEFF Research Database (Denmark)
Gregersen, Ida Bülow; Madsen, Henrik; Rosbjerg, Dan
2017-01-01
as the explanatory variables in the regional and temporal domain, respectively. Further analysis of partial duration series with nonstationary and regional thresholds shows that the mean exceedances also exhibit a significant variation in space and time for some rainfall durations, while the shape parameter is found...... of extreme rainfall. The framework is built on a partial duration series approach with a nonstationary, regional threshold value. The model is based on generalized linear regression solved by generalized estimation equations. It allows a spatial correlation between the stations in the network and accounts...... furthermore for variable observation periods at each station and in each year. Marginal regional and temporal regression models solved by generalized least squares are used to validate and discuss the results of the full spatiotemporal model. The model is applied on data from a large Danish rain gauge network...
Sagioglou, Niki E; Manta, Areti K; Giannarakis, Ioannis K; Skouroliakou, Aikaterini S; Margaritis, Lukas H
2016-01-01
Present generations are being repeatedly exposed to different types and doses of non-ionizing radiation (NIR) from wireless technologies (FM radio, TETRA and TV stations, GSM and UMTS phones/base stations, Wi-Fi networks, DECT phones). Although there is controversy on the published data regarding the non-thermal effects of NIR, studies have convincingly demonstrated bioeffects. Their results indicate that modulation, intensity, exposure duration and model system are important factors determining the biological response to irradiation. Attempting to address the dependence of NIR bioeffectiveness on these factors, apoptosis in the model biological system Drosophila melanogaster was studied under different exposure protocols. A signal generator was used operating alternatively under Continuous Wave (CW) or Frequency Modulation (FM) emission modes, at three power output values (10 dB, 0, -10 dB), under four carrier frequencies (100, 395, 682, 900 MHz). Newly emerged flies were exposed either acutely (6 min or 60 min on the 6th day), or repeatedly (6 min or 60 min daily for the first 6 days of their life). All exposure protocols resulted in an increase of apoptotic cell death (ACD) observed in egg chambers, even at very low electric field strengths. FM waves seem to have a stronger effect in ACD than continuous waves. Regarding intensity and temporal exposure pattern, EMF-biological tissue interaction is not linear in response. Intensity threshold for the induction of biological effects depends on frequency, modulation and temporal exposure pattern with unknown so far mechanisms. Given this complexity, translating such experimental data into possible human exposure guidelines is yet arbitrary.
Interactions of cosmic rays in the atmosphere: growth curves revisited
Energy Technology Data Exchange (ETDEWEB)
Obermeier, A.; Boyle, P.; Müller, D. [Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States); Hörandel, J., E-mail: a.obermeier@astro.ru.nl [Radboud Universiteit Nijmegen, 6525-HP Nijmegen (Netherlands)
2013-12-01
Measurements of cosmic-ray abundances on balloons are affected by interactions in the residual atmosphere above the balloon. Corrections for such interactions are particularly important for observations of rare secondary particles such as boron, antiprotons, and positrons. These corrections either can be calculated if the relevant cross sections in the atmosphere are known or may be empirically determined by extrapolation of the 'growth curves', i.e., the individual particle intensities as functions of atmospheric depth. The growth-curve technique is particularly attractive for long-duration balloon flights where the periodic daily altitude variations permit rather precise determinations of the corresponding particle intensity variations. We determine growth curves for nuclei from boron (Z = 5) to iron (Z = 26) using data from the 2006 Arctic balloon flight of the TRACER detector for cosmic-ray nuclei, and we compare the growth curves with predictions from published cross section values. In general, good agreement is observed. We then study the boron/carbon abundance ratio and derive a simple and energy-independent correction term for this ratio. We emphasize that the growth-curve technique can be developed further to provide highly accurate tests of published interaction cross section values.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Based on the daily turbulent heat fluxes and related meteorological variables datasets (1985-2006) from Objectively Analyzed air-sea Fluxes (OAFlux) Project of Woods Hole Oceanographic Institution (WHOI), characteristics of low-frequency oscillation intensity of air-sea turbulent heat fluxes over the northwest Pacific are analyzed by linear perturbation method and correlation analysis. It can be concluded that: 1) the distribution of low-frequency oscillation intensity of latent heat flux (LHF) over the northwest Pacific is mainly affected by that of low-frequency oscillation intensity of anomalous air-sea humidity gradient (Δq′) as well as mean air-sea humidity gradient ( Δ q), while the distribution of low-frequency oscillation intensity of sensible heat flux (SHF) is mainly affected by that of low-frequency oscillation intensity of anomalous air-sea temperature gradient (ΔT′). 2) The low-frequency oscillation of turbulent heat fluxes over the northwest Pacific is the strongest in winter and the weakest in summer. And the seasonal transition of low-frequency oscillation intensity of LHF is jointly influenced by those of low-frequency oscillation intensity of Δq′, low-frequency oscillation intensity of anomalous wind speed (U′), Δ q and mean wind speed (U ), while the seasonal transition of low-frequency oscillation intensity of SHF is mainly influenced by those of low-frequency oscillation intensity of ΔT′ and U . 3) Over the tropical west Pacific and sea areas north of 20°N, the low-frequency oscillation of LHF (SHF) is mainly influenced by atmospheric variables qa′ (Ta′) and U′, indicating an oceanic response to overlying atmospheric forcing. In contrast, over the tropical eastern and central Pacific south of 20°N, qs′ (Ts′) also greatly influences the low-frequency oscillation of LHF (SHF).
Parker, T. J.; Pieri, D. C.
1985-01-01
In assessing the relative ages of the geomorphic/geologic units, crater counts of the entire unit or nearly the entire unit were made and summed in order to get a more accurate value than obtainable by counts of isolated sections of each unit. Cumulative size-frequency counts show some interesting relationships. Most of the units show two distinct crater populations with a flattening out of the distribution curve at and below 10 km diameter craters. Above this crater size the curves for the different units diverge most notably. In general, the variance may reflect the relative ages of these units. At times, however, in the larger crater size range, these curves can overlap and cross on another. Also the error bars at these larger sizes are broader (and thus more suspect), since counts of larger craters show more scatter, whereas the unit areas remain constant. Occasional clusters of relatively large craters within a given unit, particularly one of limited areal extent, can affect the curve so that the unit might seem to be older than units which it overlies or cuts.
Hovnanyan, K; Kalantaryan, V; Trchounian, A
2017-09-01
A low-intensity electromagnetic field of extremely high frequency has inhibitory and stimulatory effects on bacteria, including Enterococcus hirae. It was shown that the low-intensity (the incident power density of 0·06 mW cm -2 ) electromagnetic field at the frequencies of 51·8 GHz and 53 GHz inhibited E. hirae ATCC 9790 bacterial growth rate; a stronger effect was observed with 53 GHz, regardless of exposure duration (0·5 h, 1 h or 2 h). Scanning electron microscopy analysis of these effects has been done; the cells were of spherical shape. Electromagnetic field at 53 GHz, but not 51·8 GHz, changed the cell size-the diameter was enlarged 1·3 fold at 53 GHz. These results suggest the difference in mechanisms of action on bacteria for electromagnetic fields at 51·8 GHz and 53 GHz. A stronger inhibitory effect of low-intensity electromagnetic field on Enterococcus hirae ATCC 9790 bacterial growth rate was observed with 53 GHz vs 51·8 GHz, regardless of exposure duration. Scanning electron microscopy analysis showed that almost all irradiated cells in the population have spherical shapes similar to nonirradiated ones, but they have increased diameters in case of irradiated cells at 53 GHz, but not 51·8 GHz. The results are novel, showing distinguishing effects of low-intensity electromagnetic field of different frequencies. They could be applied in treatment of food and different products in medicine and veterinary, where E. hirae plays an important role. © 2017 The Society for Applied Microbiology.
Modeling off-frequency binaural masking for short- and long-duration signals.
Nitschmann, Marc; Yasin, Ifat; Henning, G Bruce; Verhey, Jesko L
2017-08-01
Experimental binaural masking-pattern data are presented together with model simulations for 12- and 600-ms signals. The masker was a diotic 11-Hz wide noise centered on 500 Hz. The tonal signal was presented either diotically or dichotically (180° interaural phase difference) with frequencies ranging from 400 to 600 Hz. The results and the modeling agree with previous data and hypotheses; simulations with a binaural model sensitive to monaural modulation cues show that the effect of duration on off-frequency binaural masking-level differences is mainly a result of modulation cues which are only available in the monaural detection of long signals.
Directory of Open Access Journals (Sweden)
Paul eMiller
2013-05-01
Full Text Available Randomly connected recurrent networks of excitatory groups of neurons can possess a multitude of attractor states. When the internal excitatory synapses of these networks are depressing, the attractor states can be destabilized with increasing input. This leads to an itinerancy, where with either repeated transient stimuli, or increasing duration of a single stimulus, the network activity advances through sequences of attractor states. We find that the resulting network state, which persists beyond stimulus offset, can encode the number of stimuli presented via a distributed representation of neural activity with non-monotonic tuning curves for most neurons. Increased duration of a single stimulus is encoded via different distributed representations, so unlike an integrator, the network distinguishes separate successive presentations of a short stimulus from a single presentation of a longer stimulus with equal total duration. Moreover, different amplitudes of stimulus cause new, distinct activity patterns, such that changes in stimulus number, duration and amplitude can be distinguished from each other. These properties of the network depend on dynamic depressing synapses, as they disappear if synapses are static. Thus short-term synaptic depression allows a network to store separately the different dynamic properties of a spatially constant stimulus.
RainyDay: An Online, Open-Source Tool for Physically-based Rainfall and Flood Frequency Analysis
Wright, D.; Yu, G.; Holman, K. D.
2017-12-01
Flood frequency analysis in ungaged or changing watersheds typically requires rainfall intensity-duration-frequency (IDF) curves combined with hydrologic models. IDF curves only depict point-scale rainfall depth, while true rainstorms exhibit complex spatial and temporal structures. Floods result from these rainfall structures interacting with watershed features such as land cover, soils, and variable antecedent conditions as well as river channel processes. Thus, IDF curves are traditionally combined with a variety of "design storm" assumptions such as area reduction factors and idealized rainfall space-time distributions to translate rainfall depths into inputs that are suitable for flood hydrologic modeling. The impacts of such assumptions are relatively poorly understood. Meanwhile, modern precipitation estimates from gridded weather radar, grid-interpolated rain gages, satellites, and numerical weather models provide more realistic depictions of rainfall space-time structure. Usage of such datasets for rainfall and flood frequency analysis, however, are hindered by relatively short record lengths. We present RainyDay, an open-source stochastic storm transposition (SST) framework for generating large numbers of realistic rainfall "scenarios." SST "lengthens" the rainfall record by temporal resampling and geospatial transposition of observed storms to extract space-time information from regional gridded rainfall data. Relatively short (10-15 year) records of bias-corrected radar rainfall data are sufficient to estimate rainfall and flood events with much longer recurrence intervals including 100-year and 500-year events. We describe the SST methodology as implemented in RainyDay and compare rainfall IDF results from RainyDay to conventional estimates from NOAA Atlas 14. Then, we demonstrate some of the flood frequency analysis properties that are possible when RainyDay is integrated with a distributed hydrologic model, including robust estimation of flood
Medeiros, Flávia Vanessa; Bottaro, Martim; Vieira, Amilton; Lucas, Tiago Pires; Modesto, Karenina Arrais; Bo, Antonio Padilha L; Cipriano, Gerson; Babault, Nicolas; Durigan, João Luiz Quagliotti
2017-06-01
To test the hypotheses that, as compared with pulsed current with the same pulse duration, kilohertz frequency alternating current would not differ in terms of evoked-torque production and perceived discomfort, and as a result, it would show the same current efficiency. A repeated-measures design with 4 stimuli presented in random order was used to test 25 women: (1) 500-microsecond pulse duration, (2) 250-microsecond pulse duration, (3) 500-microsecond pulse duration and low carrier frequency (1 kHz), (4) 250-microsecond pulse duration and high carrier frequency (4 kHz). Isometric peak torque of quadriceps muscle was measured using an isokinetic dynamometer. Discomfort was measured using a visual analog scale. Currents with long pulse durations induced approximately 21% higher evoked torque than short pulse durations. In addition, currents with 500 microseconds delivered greater amounts of charge than stimulation patterns using 250-microsecond pulse durations (P torque and discomfort. However, neuromuscular electrical stimulation (NMES) with longer pulse duration induces higher NMES-evoked torque, regardless of the carrier frequency. Pulse duration is an important variable that should receive more attention for an optimal application of NMES in clinical settings.
Grison, B.; Escoubet, C. P.; Pitout, F.; Cornilleau-Wehrlin, N.; Dandouras, I.; Lucek, E.
2009-04-01
In the mid altitude cusp region the DC magnetic field presents a diamagnetic cavity due to intense ion earthward flux coming from the magnetosheath. A strong ultra low frequency (ULF) magnetic activity is also commonly observed in this region. Most of the mid altitude cusp statistical studies have focused on the location of the cusp and its dependence and response to solar wind, interplanetary magnetic field, dipole tilt angle parameters. In our study we use the database build by Pitout et al. (2006) in order to study the link of wave power in the ULF range (0.35-10Hz) measured by STAFF SC instrument with the ion plasma properties as measured by CIS (and CODIF) instrument as well as the diamagnetic cavity in the mid-altitude cusp region with FGM data. To compare the different crossings we don`t use the cusp position and dynamics but we use a normalized cusp crossing duration that permits to easily average the properties over a large number of crossings. As usual in the cusp, it is particularly relevant to sort the crossings by the corresponding interplanetary magnetic field (IMF) orientation in order to analyse the results. In particular we try to find out what is the most relevant parameter to link the strong wave activity with. The global statistic confirms previous single case observations that have noticed a simultaneity between ion injections and wave activity enhancements. We will also present results concerning other ion parameters and the diamagnetic cavity observed in the mid altitude cusp region.
Tomiyasu, Kentaro; Takagi, Ryo; Iwasaki, Ryosuke; Yoshizawa, Shin; Umemura, Shin-ichiro
2017-07-01
In high-intensity focused ultrasound (HIFU) treatment, controlling the ultrasound dose at each focal target spot is important because it is a problem that the length of the coagulated region in front of the focal point deviates owing to the differences in absorption in each focal target spot and attenuation in the intervening tissues. In this study, the detected changes in the power spectra of HIFU echoes were used by controlling the HIFU duration in the “trigger HIFU” sequence with the aim to increase coagulation size through the enhancement of the ultrasonic heating by the cavitation induced by the preceding extremely high intensity short “trigger” pulse. The result shows that this method can be used to detect boiling bubbles and the following generated cavitation bubbles at their early stage. By automatically stopping HIFU exposure immediately after detecting the bubbles, overheating was prevented and the deviation of the length of the coagulated region was reduced.
Massage Therapy and Frequency of Chronic Tension Headaches
Quinn, Christopher; Chandler, Clint; Moraska, Albert
2002-01-01
Objectives. The effect of massage therapy on chronic nonmigraine headache was investigated. Methods. Chronic tension headache sufferers received structured massage therapy treatment directed toward neck and shoulder muscles. Headache frequency, duration, and intensity were recorded and compared with baseline measures. Results. Compared with baseline values, headache frequency was significantly reduced within the first week of the massage protocol. The reduction of headache frequency continued for the remainder of the study (P = .009). The duration of headaches tended to decrease during the massage treatment period (P = .058). Headache intensity was unaffected by massage (P = .19). Conclusions. The muscle-specific massage therapy technique used in this study has the potential to be a functional, nonpharmacological intervention for reducing the incidence of chronic tension headache. PMID:12356617
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Anton Rahardjo
2015-05-01
Full Text Available Epidemiological study of tooth brushing is essential to evaluate dental health of a country. Objective: To obtain data on tooth brushing frequency, time of day and duration from adults and children in Jakarta, Indonesia. Methods: Toothbrushes containing data loggers were distributed to 120 random families in Jakarta to record how many times a day, when and for how long subjects brushed their teeth. The families were each composed of a mother, father and two children aged between 6 and 15 years. Results: The mean brushing frequency of the population was 1.27 times per day. The majority of the tooth brushing (46% was performed in the morning. The mean tooth brushing duration of this population was 57.29 seconds. The mothers’ tooth brushing frequencies tended to be higher than that of the other family members, and the fathers tended to brush their teeth longer. Conclusion: Effective education aimed at increasing both the duration and frequency of tooth brushing from once to twice per day is urgently required in Indonesia.DOI: 10.14693/jdi.v21i3.251
Historical Cost Curves for Hydrogen Masers and Cesium Beam Frequency and Timing Standards
Remer, D. S.; Moore, R. C.
1985-01-01
Historical cost curves were developed for hydrogen masers and cesium beam standards used for frequency and timing calibration in the Deep Space Network. These curves may be used to calculate the cost of future hydrogen masers or cesium beam standards in either future or current dollars. The cesium beam standards are decreasing in cost by about 2.3% per year since 1966, and hydrogen masers are decreasing by about 0.8% per year since 1978 relative to the National Aeronautics and Space Administration inflation index.
The partial duration series method in regional index-flood modeling
DEFF Research Database (Denmark)
Madsen, Henrik; Rosbjerg, Dan
1997-01-01
A regional index-flood method based on the partial duration series model is introduced. The model comprises the assumptions of a Poisson-distributed number of threshold exceedances and generalized Pareto (GP) distributed peak magnitudes. The regional T-year event estimator is based on a regional...... estimator is superior to the at-site estimator even in extremely heterogenous regions, the performance of the regional estimator being relatively better in regions with a negative shape parameter. When the record length increases, the relative performance of the regional estimator decreases, but it is still...
Platanou, T; Geladas, N
2006-11-01
In this study, we assessed exercise intensity in 20 water polo games of different duration. The hypothesis that right wing players perform at a higher intensity than back and forward central players was also tested. Thirty water polo players, equally split between three field positions, participated in the study. Initially, their performance-related physiological capabilities were evaluated. Subsequently, during water polo games of short (4 x 7-min periods) or long duration (4 x 9-min periods), heart rate was monitored continuously and blood lactate concentration was measured at the end of each period. Activity patterns were also recorded using a video camera. Mean heart rate over the entire game was 156 +/- 18 beats x min(-1). Overall exercise intensity fluctuated around a value corresponding to the lactate threshold (4.03 +/- 0.96 mmol x l(-1), 86 +/- 5% of peak heart rate) and decreased (P game time (4.22 +/- 1.8 and 3.47 +/- 1.9 mmol x l(-1) in the second and fourth quarter, respectively). During the last 6 min, heart rate was higher (P games of short duration (156 +/- 3 beats x min(-1)) than in games of long duration (152 +/- 8 beats x min(-1)). Video analysis showed that the percentage of time spent in low-intensity activities (i.e. "out of game") was lower (23 vs. 26%), whereas that in high-intensity activities (i.e. "sprinting crawl") was higher (21 vs. 19%), in games of short compared with long duration. No difference was observed among players of various field positions in any of the variables examined. Thus during match-play, games of long duration produced significantly lower heart rate responses than games of short duration, and the physiological response exhibited by the players was not affected by field position. The water polo authorities should consider these results before changing game duration and coaches should prepare their athletes accordingly.
Herve, Gwenael; Chauvin, Annick; Lanos, Philippe
2014-05-01
At the regional scale, the dispersion between archaeomagnetic data and especially archaeointensities suggests that some of them may be biased. As a consequence, it appears necessary to perform a selection of available data before to compute mean regional secular variation curves or geomagnetic models. However the definition of suitable selection criteria is not obvious and we need to know how to manage "old" data acquired during the 60-70s. The Western Europe directional and intensity data set from 1500 BC to 200 AD allows to discuss these issues. It has recently been enhanced by 39 new archaeodirections and 23 new archaeointensities (Hervé et al., 2013a and 2013b data sets and 5 unpublished data). First, the whole Western Europe data set was selected but the strong dispersion restricted the accuracy and the reliability of the new Western Europe secular variation curves at Paris. The causes of the dispersion appear different between archaeodirections and archaeointensities. In the directional data set, the main problem comes from some age errors in the oldest published data. Since their publication their archaeological dating may have changed of 50 years or more. For intensity data that were acquired much more recently, the dispersion mainly results from the use of unreliable archaeointensity protocols. We propose a weighting approach based on the number of specimens and the use of pTRM-checks, anisotropy and cooling rate corrections. Only 63% of available archaeodirections and 32% of archaeointensities were used to build the new Western Europe secular variation curves from 1500 BC to 200 AD. These curves reveal that selecting the reference data avoids wrong estimations of the shape of the secular variation curves, the secular variation rate, the dating of archaeomagnetic jerks... Finally, it is worth pointing out that current geomagnetic global models take into account almost all the data that we decided to reject. It could partly explain why their predictions at
Li, Lu; Stefan, Melanie I.; Le Novère, Nicolas
2012-01-01
NMDA receptor dependent long-term potentiation (LTP) and long-term depression (LTD) are two prominent forms of synaptic plasticity, both of which are triggered by post-synaptic calcium elevation. To understand how calcium selectively stimulates two opposing processes, we developed a detailed computational model and performed simulations with different calcium input frequencies, amplitudes, and durations. We show that with a total amount of calcium ions kept constant, high frequencies of calcium pulses stimulate calmodulin more efficiently. Calcium input activates both calcineurin and Ca2+/calmodulin-dependent protein kinase II (CaMKII) at all frequencies, but increased frequencies shift the relative activation from calcineurin to CaMKII. Irrespective of amplitude and duration of the inputs, the total amount of calcium ions injected adjusts the sensitivity of the system to calcium input frequencies. At a given frequency, the quantity of CaMKII activated is proportional to the total amount of calcium. Thus, an input of a small amount of calcium at high frequencies can induce the same activation of CaMKII as a larger amount, at lower frequencies. Finally, the extent of activation of CaMKII signals with high calcium frequency is further controlled by other factors, including the availability of calmodulin, and by the potency of phosphatase inhibitors. PMID:22962589
Dunton, Genevieve Fridlund; Berrigan, David; Ballard-Barbash, Rachel; Perna, Frank; Graubard, Barry I.; Atienza, Audie A.
2012-01-01
We used data from the American Time Use Survey (years 2003-06) to analyze whether the intensity and duration of high school students' (ages 15-18 years) sports and exercise bouts differed across physical and social environments. Boys' sports and exercise bouts were more likely to reach a vigorous intensity when taking place at school and with…
Caporali, E.; Chiarello, V.; Galeati, G.
2014-12-01
Peak discharges estimates for a given return period are of primary importance in engineering practice for risk assessment and hydraulic structure design. Different statistical methods are chosen here for the assessment of flood frequency curve: one indirect technique based on the extreme rainfall event analysis, the Peak Over Threshold (POT) model and the Annual Maxima approach as direct techniques using river discharge data. In the framework of the indirect method, a Monte Carlo simulation approach is adopted to determine a derived frequency distribution of peak runoff using a probabilistic formulation of the SCS-CN method as stochastic rainfall-runoff model. A Monte Carlo simulation is used to generate a sample of different runoff events from different stochastic combination of rainfall depth, storm duration, and initial loss inputs. The distribution of the rainfall storm events is assumed to follow the GP law whose parameters are estimated through GEV's parameters of annual maximum data. The evaluation of the initial abstraction ratio is investigated since it is one of the most questionable assumption in the SCS-CN model and plays a key role in river basin characterized by high-permeability soils, mainly governed by infiltration excess mechanism. In order to take into account the uncertainty of the model parameters, this modified approach, that is able to revise and re-evaluate the original value of the initial abstraction ratio, is implemented. In the POT model the choice of the threshold has been an essential issue, mainly based on a compromise between bias and variance. The Generalized Extreme Value (GEV) distribution fitted to the annual maxima discharges is therefore compared with the Pareto distributed peaks to check the suitability of the frequency of occurrence representation. The methodology is applied to a large dam in the Serchio river basin, located in the Tuscany Region. The application has shown as Monte Carlo simulation technique can be a useful
Chao, Yi-Sheng; Brunel, Ludovic; Faris, Peter; Veugelers, Paul J
2013-10-11
The importance of dose, frequency and duration of vitamin D supplementation for plasma 25(OH)D levels is not well described and rarely reported for supplementation that exceeds 2000 IU per day. The objective is to examine dose, frequency and duration of supplementation in relation to plasma 25(OH)D in a large population-based sample. We accessed data on 2714 volunteers that contributed to 4224 visits and applied multilevel regression. Compared to not using supplements, a minimum regimen of 1000-2000 IU once or twice per week for one month was not effective in raising 25(OH)D. Compared to this minimum regimen, higher doses of 2000-3000, 3000-4000, and 5000 IU or more were associated with a 7.49, 13.19 and 30.22 nmol/L 25(OH)D increase, respectively; frequencies of three to four, five to six and seven times/week were associated with a 5.44, 16.52 and 30.69 nmol/L increase, respectively; and supplementation of five months or longer was associated with an increase of 6.68 nmol/L (p D. Whereas dose, frequency and duration of supplementation are important to healthy subjects committed to optimizing their nutritional status, to the design of clinical trials, individual characteristics and lifestyle contribute substantially to 25(OH)D.
Directory of Open Access Journals (Sweden)
Nori Paulo Griebeler
2007-09-01
Full Text Available
Este trabalho teve como objetivo a obtenção das relações intensidade-duração-frequência para algumas localidades do Estado de Goiás e Distrito Federal, empregando-se a metodologia da desagregação da chuva de um dia. Os resultados das intensidades de precipitação obtidos pelas equações geradas neste trabalho foram comparados com os obtidos pelas equações ajustadas com base em dados de pluviogramas. As relações geradas com o método de desagregação de chuvas de um dia apresentaram desvios relativos médios que variaram de -1,6% a 43,9%, para alguns municípios nessa região. Isso limita a sua utilização nas localidades para as quais não se ajustaram as equações de regressão.
PALAVRAS-CHAVE: Chuva intensa; drenagem; intensidade-duração-frequência.
This study had the objective of obtaining rain intensityduration- frequency information for some sites in the State of Goiás and Distrito Federal, using the one-day rain disaggregation method. The precipitation intensities obtained through the equations generated in this paper were compared to those obtained by adjusted equations based on pluviographic data. The intensityduration-frequency relationships generated through pluviometric data using the one-day rain disaggregation method presented relative mean deviations varying between -1.6% and 43.9%, for some municipalities in this region. This limits its use in sites where regression equations were not adjusted.
KEY-WORDS: Intense rainfall; drainage; intensity-durationfrequency.
Institute of Scientific and Technical Information of China (English)
LI Gen; REN BaoHua; ZHENG JianOiu; WANG Jun
2009-01-01
Based on the daily turbulent heat fluxes and related meteorological variables dataeets (1985-2006) from Objectively Analyzed air-sea Fluxes (OAFlux) Project of Woods Hole Oceanographic Institution (WHOI), characteristics of low-frequency oscillation intensity of air-sea turbulent heat fluxes over the northwest Pacific are analyzed by linear perturbation method and correlation analysis. It can be concluded that: 1) the distribution of low-frequency oscillation intensity of latent heat flux (LHF) over the northwest Pacific is mainly affected by that of low-frequency oscillation intensity of anomalous air-eea humidity gradient (△q') as well as mean air-eea humidity gradient (△q), while the distribution of low-frequency oscillation Intensity of sensible heat flux (SHF) is mainly affected by that of low-frequency oscillation intensity of anomalous air-sea temperature gradient (△T'). 2) The low-frequency oscillation of turbulent heat fluxes over the northwest Pacific is the strongest in winter and the weakest in summer. And the seasonal transition of low-frequency oscillation intensity of LHF is jointly influenced by those of low-frequency oscillation intensity of △q', low-frequency oscillation intensity of anomalous wind speed (U'), △q and mean wind speed (U), while the seasonal transition of low-frequency oscillation intensity of SHF is mainly influenced by those of low-frequency oscillation Intensity of △T' and U. 3) Over the tropical west Pacific and sea areas north of 20ON, the low-frequency oscillation of LHF (SHF) is mainly influenced by atmospheric variables qa' (Ta') and U', indicating an oceanic response to overlying atmospheric forcing. In contrast, over the tropical eastern and central Pacific south of 20°N, qs' (Ts') also greatly influences the low-frequency oscillation of LHF (SHF).
Effects of Rainfall Characteristics on the Stability of Tropical Residual Soil Slope
Directory of Open Access Journals (Sweden)
Rahardjo Harianto
2016-01-01
Full Text Available Global climate change has a significant impact on rainfall characteristics, sea water level and groundwater table. Changes in rainfall characteristics may affect stability of slopes and have severe impacts on sustainable urban living. Information on the intensity, frequency and duration of rainfall is often required by geotechnical engineers for performing slope stability analyses. Many seepage analyses are commonly performed using the most extreme rainfall possible which is uneconomical in designing a slope repair or slope failure preventive measure. In this study, the historical rainfall data were analyzed and investigated to understand the characteristics of rainfall in Singapore. The frequency distribution method was used to estimate future rainfall characteristics in Singapore. New intensity-duration-frequency (IDF curves for rainfall in Singapore were developed for six different durations (10, 20, 30 min and 1, 2 and 24 h and six frequencies (2, 5, 10, 25, 50 and 100 years. The new IDF curves were used in the seepage and slope stability analyses to determine the variation of factor of safety of residual soil slopes under different rainfall intensities in Singapore.
Natsume, Takahiro; Ishida, Masaki; Kitagawa, Kakuya; Nagata, Motonori; Sakuma, Hajime; Ichihara, Takashi
2015-11-01
The purpose of this study was to develop a method to determine time discrepancies between input and myocardial time-signal intensity (TSI) curves for accurate estimation of myocardial perfusion with first-pass contrast-enhanced MRI. Estimation of myocardial perfusion with contrast-enhanced MRI using kinetic models requires faithful recording of contrast content in the blood and myocardium. Typically, the arterial input function (AIF) is obtained by setting a region of interest in the left ventricular cavity. However, there is a small delay between the AIF and the myocardial curves, and such time discrepancies can lead to errors in flow estimation using Patlak plot analysis. In this study, the time discrepancies between the arterial TSI curve and the myocardial tissue TSI curve were estimated based on the compartment model. In the early phase after the arrival of the contrast agent in the myocardium, the relationship between rate constant K1 and the concentrations of Gd-DTPA contrast agent in the myocardium and arterial blood (LV blood) can be described by the equation K1={dCmyo(tpeak)/dt}/Ca(tpeak), where Cmyo(t) and Ca(t) are the relative concentrations of Gd-DTPA contrast agent in the myocardium and in the LV blood, respectively, and tpeak is the time corresponding to the peak of Ca(t). In the ideal case, the time corresponding to the maximum upslope of Cmyo(t), tmax, is equal to tpeak. In practice, however, there is a small difference in the arrival times of the contrast agent into the LV and into the myocardium. This difference was estimated to correspond to the difference between tpeak and tmax. The magnitudes of such time discrepancies and the effectiveness of the correction for these time discrepancies were measured in 18 subjects who underwent myocardial perfusion MRI under rest and stress conditions. The effects of the time discrepancies could be corrected effectively in the myocardial perfusion estimates. Copyright © 2015 Elsevier Inc. All rights
Mu, Weiwei; Hu, Zhaohui; Wang, Jing; Zhou, Binquan
2017-10-01
Nuclear magnetic resonance gyroscope (NMRG) detects the angular velocity of the vehicle utilizing the interaction between the laser beam and the alkali metal atoms along with the noble gas atoms in the alkali vapor cell. In order to reach high precision inertial measurement target, semiconductor laser in NMRG should have good intensity and frequency stability. Generally, laser intensity and frequency are stabilized separately. In this paper, a new method to stabilize laser intensity and frequency simultaneously with double-loop feedback control is presented. Laser intensity is stabilized to the setpoint value by feedback control of laser diode's temperature. Laser frequency is stabilized to the Doppler absorption peak by feedback control of laser diode's current. The feedback control of current is a quick loop, hence the laser frequency stabilize quickly. The feedback control of temperature is a slow loop, hence the laser intensity stabilize slowly. With the feedback control of current and temperature, the laser intensity and frequency are stabilized finally. Additionally, the dependence of laser intensity and frequency on laser diode's current and temperature are analyzed, which contributes to choose suitable operating range for the laser diode. The advantage of our method is that the alkali vapor cell used for stabilizing laser frequency is the same one as the cell used for NMRG to operate, which helps to miniaturize the size of NMRG prototype. In an 8-hour continuous measurement, the long-term stability of laser intensity and frequency increased by two orders of magnitude and one order of magnitude respectively.
Heo, J. H.; Ahn, H.; Kjeldsen, T. R.
2017-12-01
South Korea is prone to large, and often disastrous, rainfall events caused by a mixture of monsoon and typhoon rainfall phenomena. However, traditionally, regional frequency analysis models did not consider this mixture of phenomena when fitting probability distributions, potentially underestimating the risk posed by the more extreme typhoon events. Using long-term observed records of extreme rainfall from 56 sites combined with detailed information on the timing and spatial impact of past typhoons from the Korea Meteorological Administration (KMA), this study developed and tested a new mixture model for frequency analysis of two different phenomena; events occurring regularly every year (monsoon) and events only occurring in some years (typhoon). The available annual maximum 24 hour rainfall data were divided into two sub-samples corresponding to years where the annual maximum is from either (1) a typhoon event, or (2) a non-typhoon event. Then, three-parameter GEV distribution was fitted to each sub-sample along with a weighting parameter characterizing the proportion of historical events associated with typhoon events. Spatial patterns of model parameters were analyzed and showed that typhoon events are less commonly associated with annual maximum rainfall in the North-West part of the country (Seoul area), and more prevalent in the southern and eastern parts of the country, leading to the formation of two distinct typhoon regions: (1) North-West; and (2) Southern and Eastern. Using a leave-one-out procedure, a new regional frequency model was tested and compared to a more traditional index flood method. The results showed that the impact of typhoon on design events might previously have been underestimated in the Seoul area. This suggests that the use of the mixture model should be preferred where the typhoon phenomena is less frequent, and thus can have a significant effect on the rainfall-frequency curve. This research was supported by a grant(2017-MPSS31
An Experimental Study on the Impact of Different-frequency Elastic Waves on Water Retention Curve
Deng, J. H.; Dai, J. Y.; Lee, J. W.; Lo, W. C.
2017-12-01
ABSTEACTOver the past few decades, theoretical and experimental studies on the connection between elastic wave attributes and the physical properties of a fluid-bearing porous medium have attracted the attention of many scholars in fields of porous medium flow and hydrogeology. It has been previously determined that the transmission of elastic waves in a porous medium containing two immiscible fluids will have an effect on the water retention curve, but it has not been found that the water retention curve will be affected by the frequency of elastic vibration waves or whether the effect on the soil is temporary or permanent. This research is based on a sand box test in which the soil is divided into three layers (a lower, middle, and upper layer). In this case, we discuss different impacts on the water retention curve during the drying process under sound waves (elastic waves) subject to three frequencies (150Hz, 300Hz, and 450Hz), respectively. The change in the water retention curve before and after the effect is then discussed. In addition, how sound waves affect the water retention curve at different depths is also observed. According to the experimental results, we discover that sound waves can cause soil either to expand or to contract. When the soil is induced to expand due to sound waves, it can contract naturally and return to the condition it was in before the influence of the sound waves. On the contrary, when the soil is induced to contract, it is unable to return to its initial condition. Due to the results discussed above, it is suggested that sound waves causing soil to expand have a temporary impact while those causing soil to contract have a permanent impact. In addition, our experimental results show how sound waves affect the water retention curve at different depths. The degree of soil expansion and contraction caused by the sound waves will differ at various soil depths. Nevertheless, the expanding or contracting of soil is only subject to the
IDF relationships using bivariate copula for storm events in Peninsular Malaysia
Ariff, N. M.; Jemain, A. A.; Ibrahim, K.; Wan Zin, W. Z.
2012-11-01
SummaryIntensity-duration-frequency (IDF) curves are used in many hydrologic designs for the purpose of water managements and flood preventions. The IDF curves available in Malaysia are those obtained from univariate analysis approach which only considers the intensity of rainfalls at fixed time intervals. As several rainfall variables are correlated with each other such as intensity and duration, this paper aims to derive IDF points for storm events in Peninsular Malaysia by means of bivariate frequency analysis. This is achieved through utilizing the relationship between storm intensities and durations using the copula method. Four types of copulas; namely the Ali-Mikhail-Haq (AMH), Frank, Gaussian and Farlie-Gumbel-Morgenstern (FGM) copulas are considered because the correlation between storm intensity, I, and duration, D, are negative and these copulas are appropriate when the relationship between the variables are negative. The correlations are attained by means of Kendall's τ estimation. The analysis was performed on twenty rainfall stations with hourly data across Peninsular Malaysia. Using Akaike's Information Criteria (AIC) for testing goodness-of-fit, both Frank and Gaussian copulas are found to be suitable to represent the relationship between I and D. The IDF points found by the copula method are compared to the IDF curves yielded based on the typical IDF empirical formula of the univariate approach. This study indicates that storm intensities obtained from both methods are in agreement with each other for any given storm duration and for various return periods.
Frerichs, I; Dargaville, P A; Rimensberger, P C
2013-06-01
Measurement of regional lung volume changes during a quasi-static pressure-volume (PV) manoeuvre using electrical impedance tomography (EIT) could be used to assess regional respiratory system mechanics and to determine optimal ventilator settings in individual patients. Using this approach, we studied regional respiratory system mechanics in healthy and lung-injured animals, before and after surfactant administration during inflation and deflation PV manoeuvres. The comparison of the EIT-derived regional PV curves in ventral, middle and dorsal regions of the right and left lungs showed not only different amounts of hysteresis in these regions but also marked differences among different landmark pressures calculated on the inflation and deflation limbs of the curves. Regional pressures at maximum compliance as well as the lower and upper pressures of maximum compliance change differed between the inflation and deflation and increased from ventral to dorsal regions in all lung conditions. All these pressure values increased in the injured and decreased in the surfactant treated lungs. Examination of regional respiratory system mechanics using EIT enables the assessment of spatial and temporal heterogeneities in the ventilation distribution. Characteristic landmarks on the inflation and especially on the deflation limb of regional PV curves may become useful measures for guiding mechanical ventilation.
International Nuclear Information System (INIS)
Frerichs, I; Dargaville, P A; Rimensberger, P C
2013-01-01
Measurement of regional lung volume changes during a quasi-static pressure–volume (PV) manoeuvre using electrical impedance tomography (EIT) could be used to assess regional respiratory system mechanics and to determine optimal ventilator settings in individual patients. Using this approach, we studied regional respiratory system mechanics in healthy and lung-injured animals, before and after surfactant administration during inflation and deflation PV manoeuvres. The comparison of the EIT-derived regional PV curves in ventral, middle and dorsal regions of the right and left lungs showed not only different amounts of hysteresis in these regions but also marked differences among different landmark pressures calculated on the inflation and deflation limbs of the curves. Regional pressures at maximum compliance as well as the lower and upper pressures of maximum compliance change differed between the inflation and deflation and increased from ventral to dorsal regions in all lung conditions. All these pressure values increased in the injured and decreased in the surfactant treated lungs. Examination of regional respiratory system mechanics using EIT enables the assessment of spatial and temporal heterogeneities in the ventilation distribution. Characteristic landmarks on the inflation and especially on the deflation limb of regional PV curves may become useful measures for guiding mechanical ventilation. (paper)
Wang, Yanfang; Toor, Sonia S; Gautam, Ramesh; Henson, David B
2011-06-28
To describe different patterns of blinking in patients undergoing a visual field test and to establish whether the blink parameters are related to threshold variability. Thirty-nine patients with diagnosed or suspected glaucoma were recruited to undertake a perimetric task twice. Blinks were detected with a video eye-tracker system that records at a sampling rate of 60 Hz. Blink frequency, duration, and episodes of microsleep (eye closures >500 ms) were analyzed, and correlated with test-retest threshold variability. The timing of blinks with respect to stimulus presentation was analyzed and the percentage of seen stimuli for all presentations (POS(overall)) and those overlapped with blinks (POS(overlapped)) were compared. Blink frequency ranged from 0 to 58 per minute. A significant increase in blink frequency was observed in the second test (P POS(overall) and POS(overlapped) was significant (P POS(overlapped) was observed with the increase of overlap duration. A wide range of blink frequencies was observed during perimetric testing. Although no blink parameters showed significant influence on threshold variability, when the blinks overlapped with a stimulus presentation, the probability of seeing was reduced. For suprathreshold stimuli, blinks often occurred after the presentation, whereas for subthreshold presentations, there was no relationship to presentation time.
Regional frequency analysis of extreme rainfall in Belgium based on radar estimates
Directory of Open Access Journals (Sweden)
E. Goudenhoofdt
2017-10-01
Full Text Available In Belgium, only rain gauge time series have been used so far to study extreme rainfall at a given location. In this paper, the potential of a 12-year quantitative precipitation estimation (QPE from a single weather radar is evaluated. For the period 2005–2016, 1 and 24 h rainfall extremes from automatic rain gauges and collocated radar estimates are compared. The peak intensities are fitted to the exponential distribution using regression in Q-Q plots with a threshold rank which minimises the mean squared error. A basic radar product used as reference exhibits unrealistic high extremes and is not suitable for extreme value analysis. For 24 h rainfall extremes, which occur partly in winter, the radar-based QPE needs a bias correction. A few missing events are caused by the wind drift associated with convective cells and strong radar signal attenuation. Differences between radar and gauge rainfall values are caused by spatial and temporal sampling, gauge underestimations and radar errors. Nonetheless the fit to the QPE data is within the confidence interval of the gauge fit, which remains large due to the short study period. A regional frequency analysis for 1 h duration is performed at the locations of four gauges with 1965–2008 records using the spatially independent QPE data in a circle of 20 km. The confidence interval of the radar fit, which is small due to the sample size, contains the gauge fit for the two closest stations from the radar. In Brussels, the radar extremes are significantly higher than the gauge rainfall extremes, but similar to those observed by an automatic gauge during the same period. The extreme statistics exhibit slight variations related to topography. The radar-based extreme value analysis can be extended to other durations.
Influence of Media on Seasonal Influenza Epidemic Curves.
Saito, Satoshi; Saito, Norihiro; Itoga, Masamichi; Ozaki, Hiromi; Kimura, Toshiyuki; Okamura, Yuji; Murakami, Hiroshi; Kayaba, Hiroyuki
2016-09-01
Theoretical investigations predicting the epidemic curves of seasonal influenza have been demonstrated so far; however, there is little empirical research using ever accumulated epidemic curves. The effects of vaccine coverage and information distribution on influenza epidemics were evaluated. Four indices for epidemics (i.e., onset-peak duration, onset-end duration, ratio of the onset-peak duration to onset-end duration and steepness of epidemic curves) were defined, and the correlations between these indices and anti-flu drug prescription dose, vaccine coverage, the volume of media and search trend on influenza through internet were analyzed. Epidemiological data on seasonal influenza epidemics from 2002/2003 to 2013/2014 excluding 2009/2010 season were collected from National Institute of Infectious Diseases of Japan. The onset-peak duration and its ratio to onset-end duration correlated inversely with the volume of anti-flu drug prescription. Onset-peak duration correlated positively with media information volume on influenza. The steepness of the epidemic curve, and anti-flu drug prescription dose inversely correlated with the volume of media information. Pre-epidemic search trend and media volume on influenza correlated with the vaccine coverage in the season. Vaccine coverage had no strong effect on epidemic curve. Education through media has an effect on the epidemic curve of seasonal influenza. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.
Application of time–frequency wavelet analysis in the reflectometry of thin films
Energy Technology Data Exchange (ETDEWEB)
Astaf’ev, S. B., E-mail: bard@crys.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation); Shchedrin, B. M. [Moscow State University, Faculty of Computational Mathematics and Cybernetics (Russian Federation); Yanusova, L. G. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation)
2017-03-15
The application of time–frequency wavelet analysis for solving the reflectometry inverse problem is considered. It is shown that a simultaneous transform of specular intensity curve, depending on the grazing angle and spatial frequency, allows one to determine not only the thickness but also the alteration order of individual regions (layers) with characteristic behavior of electron density. This information makes it possible to reconstruct the electron density profile in the film cross section as a whole (i.e., to solve the inverse reflectometry problem). The application of the time–frequency transform is illustrated by examples of reconstructing (based on X-ray reflectivity data) the layer alternation order in models of two-layer films with inverted arrangement of layers and a four-layer film on a solid substrate.
Analysis of future drought characteristics in China using the regional climate model CCLM
Huang, Jinlong; Zhai, Jianqing; Jiang, Tong; Wang, Yanjun; Li, Xiucang; Wang, Run; Xiong, Ming; Su, Buda; Fischer, Thomas
2018-01-01
In this paper, the intensity, area and duration of future droughts in China are analyzed using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). The SPI and SPEI are used to evaluate the simulation ability of drought characteristics with the regional climate model COSMO-CLM (CCLM). The projected intensity and duration of future drought events are analyzed for the period 2016-2050 under three different respective concentration pathways (RCPs). The simulated and projected drought events are analyzed by applying the intensity-area-duration method. The results show that CCLM has a robust capability to simulate the average drought characteristics, while some regional disparities are not well captured, mainly the simulation of more drought events of shorter duration in Northwest China. For the future period 2016-2050, more intense dryness conditions are projected for China. An increase in evapotranspiration is found all over China, while a reduction in precipitation is apparent in the southern river basins. The increase in evapotranspiration plays an important role in the changes of future droughts over the northern river basins and southern river basins. Under RCP2.6, drought events of longer duration and with higher frequency are projected for the southwest and southeast of China. Under RCP4.5 and RCP8.5, a continuing tendency to more dry conditions is projected along a dryness band stretching from the southwest to the northeast of China. More frequent drought events of longer duration are projected in the southwestern river basins. For all future droughts, larger extents are projected, especially for events with long-term duration. The projected long-term drought events will occur more often and more severe than during the baseline period, and their central locations will likely shift towards Southeast China. The results of this study can be used to initiate and strengthen drought adaptation measures at
Energy intensity and its determinants in China's regional economies
International Nuclear Information System (INIS)
Wu Yanrui
2012-01-01
This paper contributes to the existing literature as well as policy debates by examining energy intensity and its determinants in China's regional economies. The analysis is based on a comprehensive database of China's regional energy balance constructed for this project. Through its focus on regional China, this study extends the existing literature, which mainly covers nationwide studies. It is found in this paper that energy intensity declined substantially in China. The main contributing factor is the improvement in energy efficiency. Changes in the economic structure have so far affected energy intensity modestly. Thus there is considerable scope to reduce energy intensity through the structural transformation of the Chinese economy in the future. - Highlights: ► First study examining energy intensity and its determinants using sectoral data in Chinese regions. ► Major findings. ► Decline in energy intensity is due to the rise in energy efficiency. ► Economic structural change has played little role. ► Growth in capital intensity alone would not lead to the decline in energy consumption.
A systematic intercomparison of regional flood frequency analysis models in a simulation framework
Ganora, Daniele; Laio, Francesco; Claps, Pierluigi
2015-04-01
Regional frequency analysis (RFA) is a well-established methodology to provide an estimate of the flood frequency curve (or other discharge-related variables), based on the fundamental concept of substituting temporal information at a site (no data or short time series) by exploiting observations at other sites (spatial information). Different RFA paradigms exist, depending on the way the information is transferred to the site of interest. Despite the wide use of such methodology, a systematic comparison between these paradigms has not been performed. The aim of this study is to provide a framework wherein carrying out the intercomparison: we thus synthetically generate data through Monte Carlo simulations for a number of (virtual) stations, following a GEV parent distribution; different scenarios can be created to represent different spatial heterogeneity patterns by manipulating the parameters of the parent distribution at each station (e.g. with a linear variation in space of the shape parameter of the GEV). A special case is the homogeneous scenario where each station record is sampled from the same parent distribution. For each scenario and each simulation, different regional models are applied to evaluate the 200-year growth factor at each station. Results are than compared to the exact growth factor of each station, which is known in our virtual world. Considered regional approaches include: (i) a single growth curve for the whole region; (ii) a multiple-region model based on cluster analysis which search for an adequate number of homogeneous subregions; (iii) a Region-of-Influence model which defines a homogeneous subregion for each site; (iv) a spatially-smooth estimation procedure based on linear regressions.. A further benchmark model is the at-site estimate based on the analysis of the local record. A comprehensive analysis of the results of the simulations shows that, if the scenario is homogeneous (no spatial variability), all the regional approaches
Czech Academy of Sciences Publication Activity Database
Konvalinková, T.; Püschel, David; Janoušková, Martina; Gryndler, M.; Jansa, J.
2015-01-01
Roč. 6, FEB 13 (2015), s. 1-11 ISSN 1664-462X Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal symbiosis * light intensity * shading duration Subject RIV: EE - Microbiology, Virology Impact factor: 4.495, year: 2015
Intensity autocorrelation measurements of frequency combs in the terahertz range
Benea-Chelmus, Ileana-Cristina; Rösch, Markus; Scalari, Giacomo; Beck, Mattias; Faist, Jérôme
2017-09-01
We report on direct measurements of the emission character of quantum cascade laser based frequency combs, using intensity autocorrelation. Our implementation is based on fast electro-optic sampling, with a detection spectral bandwidth matching the emission bandwidth of the comb laser, around 2.5 THz. We find the output of these frequency combs to be continuous even in the locked regime, but accompanied by a strong intensity modulation. Moreover, with our record temporal resolution of only few hundreds of femtoseconds, we can resolve correlated intensity modulation occurring on time scales as short as the gain recovery time, about 4 ps. By direct comparison with pulsed terahertz light originating from a photoconductive emitter, we demonstrate the peculiar emission pattern of these lasers. The measurement technique is self-referenced and ultrafast, and requires no reconstruction. It will be of significant importance in future measurements of ultrashort pulses from quantum cascade lasers.
A prediction of Power Duration Curve from the Optimal Operation of the Multi Reservoirs System
Directory of Open Access Journals (Sweden)
Abdul Wahab Younis
2013-04-01
Full Text Available This study aims of predication Power Duration Curves(PDC resulting from the optimal operation of the multi reservoirs system which comprises the reservoirs of Bakhma dam,Dokan dam and Makhool dam for the division of years over 30 years.Discrete Differential Dynamic Programming(DDDP has been employed to find the optimal operation of the said reservoirs. PDC representing the relationship between the generated hydroelectric power and percentage of operation time equaled or exceeded . The importance of these curves lies in knowing the volume of electric power available for that percentage of operation time. The results have shown that the sum of yearly hydroelectric power for average Release and for the single operation was 5410,1604,2929(Mwfor the reservoirs of Bakhma, Dokan, Makhool dams, which resulted from the application of independent DDDP technology. Also, the hydroelectric power whose generation can be guranteed for 90% of the time is 344.91,107.7,188.15 (Mw for the single operation and 309.1,134.08,140.7 (Mw for the operation as a one system for the reservoirs of Bakhma, Dokan, and Makhool dams respectively.
Type III Radio Burst Duration and SEP Events
Gopalswamy, N.; Makela, P.; Xie, H.
2010-01-01
Long-duration (>15 min), low-frequency (25 MeV. The 1-MHz duration of the type III burst (28 rein) is near the median value of type III durations found for gradual SEP events and ground level enhancement (GLE) events. Yet, there was no sign of SEP events. On the other hand, two other type III bursts from the same active region had similar duration but accompanied by WAVES type 11 bursts; these bursts were also accompanied by SEP events detected by SOHO/ERNE. This study suggests that the type III burst duration may not be a good indicator of an SEP event, consistent with the statistical study of Cliver and Ling (2009, ApJ ).
Fischer, Andreas; Keller, Denise; Liniger, Mark; Rajczak, Jan; Schär, Christoph; Appenzeller, Christof
2014-05-01
Fundamental changes in the hydrological cycle are expected in a future warmer climate. This is of particular relevance for the Alpine region, as a source and reservoir of several major rivers in Europe and being prone to extreme events such as floodings. For this region, climate change assessments based on the ENSEMBLES regional climate models (RCMs) project a significant decrease in summer mean precipitation under the A1B emission scenario by the mid-to-end of this century, while winter mean precipitation is expected to slightly rise. From an impact perspective, projected changes in seasonal means, however, are often insufficient to adequately address the multifaceted challenges of climate change adaptation. In this study, we revisit the full matrix of the ENSEMBLES RCM projections regarding changes in frequency and intensity, precipitation-type (convective versus stratiform) and temporal structure (wet/dry spells and transition probabilities) over Switzerland and surroundings. As proxies for raintype changes, we rely on the model parameterized convective and large-scale precipitation components. Part of the analysis involves a Bayesian multi-model combination algorithm to infer changes from the multi-model ensemble. The analysis suggests a summer drying that evolves altitude-specific: over low-land regions it is associated with wet-day frequency decreases of convective and large-scale precipitation, while over elevated regions it is primarily associated with a decline in large-scale precipitation only. As a consequence, almost all the models project an increase in the convective fraction at elevated Alpine altitudes. The decrease in the number of wet days during summer is accompanied by decreases (increases) in multi-day wet (dry) spells. This shift in multi-day episodes also lowers the likelihood of short dry spell occurrence in all of the models. For spring and autumn the combined multi-model projections indicate higher mean precipitation intensity north of the
Phonon transport across nano-scale curved thin films
Energy Technology Data Exchange (ETDEWEB)
Mansoor, Saad B.; Yilbas, Bekir S., E-mail: bsyilbas@kfupm.edu.sa
2016-12-15
Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.
Phonon transport across nano-scale curved thin films
International Nuclear Information System (INIS)
Mansoor, Saad B.; Yilbas, Bekir S.
2016-01-01
Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.
Continuous High Frequency Activity: A peculiar SEEG pattern related to specific brain regions
Melani, Federico; Zelmann, Rina; Mari, Francesco; Gotman, Jean
2015-01-01
Objective While visually marking the high frequency oscillations in the stereo-EEG of epileptic patients, we observed a continuous/semicontinuous activity in the ripple band (80–250 Hz), which we defined continuous High Frequency Activity (HFA). We aim to analyze in all brain regions the occurrence and significance of this particular pattern. Methods Twenty patients implanted in mesial temporal and neocortical areas were studied. One minute of slow-wave sleep was reviewed. The background was classified as continuous/semicontinuous, irregular, or sporadic based on the duration of the fast oscillations. Each channel was classified as inside/outside the seizure onset zone (SOZ) or a lesion. Results The continuous/semicontinuous HFA occurred in 54 of the 790 channels analyzed, with a clearly higher prevalence in hippocampus and occipital lobe. No correlation was found with the SOZ or lesions. In the occipital lobe the continuous/semicontinuous HFA was present independently of whether eyes were open or closed. Conclusions We describe what appears to be a new physiological High Frequency Activity, independent of epileptogenicity, present almost exclusively in the hippocampus and occipital cortex but independent of the alpha rhythm. Significance The continuous HFA may be an intrinsic characteristic of specific brain regions, reflecting a particular type of physiological neuronal activity. PMID:23768436
Directory of Open Access Journals (Sweden)
Arthur T. DeGaetano
2017-01-01
One-hundred-year recurrence interval precipitation amounts exhibit a median increase of between 5 and 10% across the state in the 2010–2039 period regardless of greenhouse gas concentration. By the 2040–2069 period, the median increase is on the order of 10–20% for the high concentration case (RCP 8.5, but remains below 10% if concentrations are lower (RCP 4.5. At the end of the century, all downscaling method climate model combinations indicate increases, with a median change of between 20 and 30% in the case of high concentrations.
Moers, Cornelia; Meyer, Antje; Janse, Esther
2017-06-01
High-frequency units are usually processed faster than low-frequency units in language comprehension and language production. Frequency effects have been shown for words as well as word combinations. Word co-occurrence effects can be operationalized in terms of transitional probability (TP). TPs reflect how probable a word is, conditioned by its right or left neighbouring word. This corpus study investigates whether three different age groups-younger children (8-12 years), adolescents (12-18 years) and older (62-95 years) Dutch speakers-show frequency and TP context effects on spoken word durations in reading aloud, and whether age groups differ in the size of these effects. Results show consistent effects of TP on word durations for all age groups. Thus, TP seems to influence the processing of words in context, beyond the well-established effect of word frequency, across the entire age range. However, the study also indicates that age groups differ in the size of TP effects, with older adults having smaller TP effects than adolescent readers. Our results show that probabilistic reduction effects in reading aloud may at least partly stem from contextual facilitation that leads to faster reading times in skilled readers, as well as in young language learners.
International Nuclear Information System (INIS)
Zolina, Olga
2014-01-01
Precipitation durations and intensities over the period 1950–2008 are analysed using daily rain gauge data from the Deutsche Wetterdienst raingauge network—one of the densest and most properly maintained precipitation observational networks in Europe. Truncated geometric distribution of the family of discrete distributions was applied for quantifying probability distribution of the durations of wet spells. Further intensities of wet spells of different durations were analysed along with wet spell lengths. During the cold season (October–March) wet periods over the whole of Germany demonstrate a robust pattern of lengthening by about 2–3% for the mean durations of wet spells and up to 6% for extremely long wet periods. This tendency is clearly associated with growing (up to 10% per decade in Eastern Germany) intensity of precipitation during long wet periods (more than 5 days) and the weakening of precipitation events associated with short and moderately long wet periods with both signals being statistically significant. Trends are superimposed with interdecadal variability, which is the strongest in Northern and Central Germany. In the warm season (April–September) there is no robust pan-German trend pattern in the wet spell durations and associated precipitation intensities. Strong structural changes in winter precipitation over Germany potentially imply growing rates of winter ground water recharge over Germany and increasing probability of winter flash and river flooding. (paper)
Rethinking non-inferiority: a practical trial design for optimising treatment duration.
Quartagno, Matteo; Walker, A Sarah; Carpenter, James R; Phillips, Patrick Pj; Parmar, Mahesh Kb
2018-06-01
Background Trials to identify the minimal effective treatment duration are needed in different therapeutic areas, including bacterial infections, tuberculosis and hepatitis C. However, standard non-inferiority designs have several limitations, including arbitrariness of non-inferiority margins, choice of research arms and very large sample sizes. Methods We recast the problem of finding an appropriate non-inferior treatment duration in terms of modelling the entire duration-response curve within a pre-specified range. We propose a multi-arm randomised trial design, allocating patients to different treatment durations. We use fractional polynomials and spline-based methods to flexibly model the duration-response curve. We call this a 'Durations design'. We compare different methods in terms of a scaled version of the area between true and estimated prediction curves. We evaluate sensitivity to key design parameters, including sample size, number and position of arms. Results A total sample size of ~ 500 patients divided into a moderate number of equidistant arms (5-7) is sufficient to estimate the duration-response curve within a 5% error margin in 95% of the simulations. Fractional polynomials provide similar or better results than spline-based methods in most scenarios. Conclusion Our proposed practical randomised trial 'Durations design' shows promising performance in the estimation of the duration-response curve; subject to a pending careful investigation of its inferential properties, it provides a potential alternative to standard non-inferiority designs, avoiding many of their limitations, and yet being fairly robust to different possible duration-response curves. The trial outcome is the whole duration-response curve, which may be used by clinicians and policymakers to make informed decisions, facilitating a move away from a forced binary hypothesis testing paradigm.
Drought Duration Biases in Current Global Climate Models
Moon, Heewon; Gudmundsson, Lukas; Seneviratne, Sonia
2016-04-01
Several droughts in the recent past are characterized by their increased duration and intensity. In particular, substantially prolonged droughts have brought major societal and economic losses in certain regions, yet climate change projections of such droughts in terms of duration is subject to large uncertainties. This study analyzes the biases of drought duration in state-of-the-art global climate model (GCM) simulations from the 5th phase of Coupled Model Intercomparison Project (CMIP5). Drought durations are defined as negative precipitation anomalies and evaluated with three observation-based datasets in the period of 1901-2010. Large spread in biases of GCMs is commonly found in all regions, with particular strong biases in North East Brazil, Africa, Northern Australia, Central America, Central and Northern Europe, Sahel and Asia. Also in most regions, the interquartile range of bias lies below 0, meaning that the GCMs tend to underestimate drought durations. Meanwhile in some regions such as Western South America, the Amazon, Sahel, West and South Africa, and Asia, considerable inconsistency among the three observation-based datasets were found. These results indicate substantial uncertainties and errors in current GCMs for simulating drought durations as well as a large spread in observation-based datasets, both of which are found to be particularly strong in those regions that are often considered to be hot spots of projected future drying. The underlying sources of these uncertainties need to be identified in further study and will be applied to constrain GCM-based drought projections under climate change.
Luo, B.; Bu, X.; Liu, S.; Gong, J.
2017-12-01
Coronal holes are sources of high-speed steams (HSS) of solar wind. When coronal holes appear at mid/low latitudes on the Sun, consequential HSSs may impact Earth and cause recurrent geospace environment disturbances, such as geomagnetic storms, relativistic electron enhancements at the geosynchronous orbit, and thermosphere density enhancements. Thus, it is of interests for space weather forecasters to predict when (arrival times), how long (time durations), and how severe (intensities) HSSs may impact Earth when they notice coronal holes on the sun and are anticipating their geoeffectiveness. In this study, relationship between coronal holes and high speed streams will be statistically investigated. Several coronal hole parameters, including passage times of solar central meridian, coronal hole longitudinal widths, intensities reflected by mean brightness, are derived using Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images for years 2011 to 2016. These parameters will be correlated with in-situ solar wind measurements measured at the L1 point by the ACE spacecraft, which can give some results that are useful for space weather forecaster in predicting the arrival times, durations, and intensities of coronal hole high-speed streams in about 3 days advance.
Effect of foot reflexology on pain intensity and duration of labor on primiparous
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Soheila Moghimi Hanjani
2012-12-01
Full Text Available Introduction: The integration of reflexology as one of the non-pharmacological pain relief methods in to midwifery care has become more common in recent years. The aim of this study was to determine the effect of reflexology on pain intensity and the duration of labor in primiparous.Materials and Methods: This clinical trial study was carried out on 80 primiparous women with low risk pregnancy that referring to Karaj hospitals (Iran then randomized in two groups, intervention group which received reflexology for 40 minutes and control group. Severity of labor pain was shown by visual analogue scale (McGill questionnaire, before, half, one and two hours after intervention. Moreover, the duration of labor was determined for both groups.Results: Severity of labor pain before and immediately after intervention foot reflexology did not vary between case and control groups (p>0.05. But half, one and two hours after it, severity of labor pain in the intervention group was lower than the control group (P<0.001. Duration of labor in the intervention group significantly was lower than the control group (P<0.001.Conclusion: Reflexology can lead to decrease in labor pain as well as duration of labor. Therefore, we can use this non-invasive technique to decrease the labor pain and encourage mothers to normal vaginal delivery that is one of the aims of midwifery
Lee, Jung Ah; Lee, Sungkyu; Cho, Hong-Jun
2017-03-14
The prevalence of adolescent electronic cigarette (e-cigarette) use has increased in most countries. This study aims to determine the relation between the frequency of e-cigarette use and the frequency and intensity of cigarette smoking. Additionally, the study evaluates the association between the reasons for e-cigarette use and the frequency of its use. Using the 2015 Korean Youth Risk Behavior Web-Based Survey, we included 6655 adolescents with an experience of e-cigarette use who were middle and high school students aged 13-18 years. We compared smoking experience, the frequency and intensity of cigarette smoking, and the relation between the reasons for e-cigarette uses and the frequency of e-cigarette use. The prevalence of e-cigarette ever and current (past 30 days) users were 10.1% and 3.9%, respectively. Of the ever users, approximately 60% used e-cigarettes not within 1 month. On the other hand, 8.1% used e-cigarettes daily. The frequent and intensive cigarette smoking was associated with frequent e-cigarette uses. The percentage of frequent e-cigarette users (≥10 days/month) was 3.5% in adolescents who did not smoke within a month, but 28.7% among daily smokers. Additionally, it was 9.1% in smokers who smoked less than 1 cigarette/month, but 55.1% in smokers who smoked ≥20 cigarettes/day. The most common reason for e-cigarette use was curiosity (22.9%), followed by the belief that they are less harmful than conventional cigarettes (18.9%), the desire to quit smoking (13.1%), and the capacity for indoor use (10.7%). Curiosity was the most common reason among less frequent e-cigarette users; however, the desire to quit smoking and the capacity for indoor use were the most common reasons among more frequent users. Results showed a positive relation between frequency or intensity of conventional cigarette smoking and the frequency of e-cigarette use among Korean adolescents, and frequency of e-cigarette use differed according to the reason for the use of
Szabó, J. A.; Kuti, L.; Bakacsi, Zs.; Pásztor, L.; Tahy, Á.
2009-04-01
Drought is one of the major weather driven natural hazards, which has most harm impacts on environment, agricultural and hydrological factors than the other hazards. In spite of the fact that Hungary - that country is situated in Central Europe - belongs to the continental climate zone (influenced by Atlantic and Mediterranean streams) and this weather conditions should be favourable for agricultural production, the drought is a serious risk factor in Hungary, especially on the so called "Great Hungarian Plain", which area has been hit by severe drought events. These drought events encouraged the Ministry of Environment and Water of Hungary to embark on a countrywide drought planning programme to coordinate drought planning efforts throughout the country, to ensure that available water is used efficiently and to provide guidance on how drought planning can be accomplished. With regard to this plan, it is indispensable to analyze the regional drought frequency and duration in the target region of the programme as fundamental information for the further works. According to these aims, first we initiated a methodological development for simulating drought in a non-contributing area. As a result of this work, it has been agreed that the most appropriate model structure for our purposes using a spatially distributed physically based Soil-Vegetation-Atmosphere Transfer (SVAT) model embedded into a Markov Chain-Monte Carlo (MCMC) algorithm for estimate multi-year drought frequency and duration. In this framework: - the spatially distributed SVAT component simulates all the fundamental SVAT processes (such as: interception, snow-accumulation and melting, infiltration, water uptake by vegetation and evapotranspiration, vertical and horizontal distribution of soil moisture, etc.) taking the groundwater table as lower, and the hydrometeorological fields as upper boundary conditions into account; - and the MCMC based stochastic component generates time series of daily weather
Czech Academy of Sciences Publication Activity Database
Konvalinková, Tereza; Püschel, David; Janoušková, Martina; Gryndler, Milan; Jansa, Jan
2015-01-01
Roč. 6, FEB 13 (2015), s. 1-11 ISSN 1664-462X R&D Projects: GA MŠk(CZ) LK11224 Institutional support: RVO:61388971 Keywords : arbuscular mycorrhizal symbiosis * light intensity * shading duration Subject RIV: EE - Microbiology, Virology Impact factor: 4.495, year: 2015
Dependence of core heating properties on heating pulse duration and intensity
Johzaki, Tomoyuki; Nagatomo, Hideo; Sunahara, Atsushi; Cai, Hongbo; Sakagami, Hitoshi; Mima, Kunioki
2009-11-01
In the cone-guiding fast ignition, an imploded core is heated by the energy transport of fast electrons generated by the ultra-intense short-pulse laser at the cone inner surface. The fast core heating (˜800eV) has been demonstrated at integrated experiments with GEKKO-XII+ PW laser systems. As the next step, experiments using more powerful heating laser, FIREX, have been started at ILE, Osaka university. In FIREX-I (phase-I of FIREX), our goal is the demonstration of efficient core heating (Ti ˜ 5keV) using a newly developed 10kJ LFEX laser. In the first integrated experiments, the LFEX laser is operated with low energy mode (˜0.5kJ/4ps) to validate the previous GEKKO+PW experiments. Between the two experiments, though the laser energy is similar (˜0.5kJ), the duration is different; ˜0.5ps in the PW laser and ˜ 4ps in the LFEX laser. In this paper, we evaluate the dependence of core heating properties on the heating pulse duration on the basis of integrated simulations with FI^3 (Fast Ignition Integrated Interconnecting) code system.
Residual stress behaviors induced by laser peening along the edge of curved models
International Nuclear Information System (INIS)
Im, Jong Bin; Grandhi, Ramana V.; Ro, Young Hee
2012-01-01
Laser peening (LP) induces high magnitude compressive residual stresses in a small region of a component. The compressive residual stresses cause plastic deformation that is resistant to fatigue fracture. Fatigue cracks are generally nucleated at critical areas, and LP is applied for those regions so as to delay the crack initiation. Many critical regions are located on the edge of the curved portion of structures because of stress concentration effects. Several investigations that are available for straight components may not give meaningful guidelines for peening curved components. Therefore, in this paper, we investigate residual stress behaviors induced by LP along the edge of curved models. Three curved models that have different curvatures are investigated for peening performance. Two types of peening configurations, which are simultaneous corner shot and sequential corner shots, are considered in order to obtain compressive residual stresses along an edge. LP simulations of multiple shots are performed to identify overlapping effects on the edge portion of a curved model. In addition, the uncertainty calculation of residual stress induced by LP considering laser pulse duration is performed
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Jianfang Zhu
Full Text Available Resting-state functional magnetic resonance imaging (R-fMRI has been intensively used to assess alterations of inter-regional functional connectivity in patients with stroke, but the regional properties of brain activity in stroke have not yet been fully investigated. Additionally, no study has examined a frequency effect on such regional properties in stroke patients, although this effect has been shown to play important roles in both normal brain functioning and functional abnormalities. Here we utilized R-fMRI to measure the amplitude of low-frequency fluctuations (ALFF and regional homogeneity (ReHo, two major methods for characterizing the regional properties of R-fMRI, in three different frequency bands (slow-5: 0.01-0.027 Hz; slow-4: 0.027-0.73 Hz; and typical band: 0.01-0.1 Hz in 19 stroke patients and 15 healthy controls. Both the ALFF and ReHo analyses revealed changes in brain activity in a number of brain regions, particularly the parietal cortex, in stroke patients compared with healthy controls. Remarkably, the regions with changed activity as detected by the slow-5 band data were more extensive, and this finding was true for both the ALFF and ReHo analyses. These results not only confirm previous studies showing abnormality in the parietal cortex in patients with stroke, but also suggest that R-fMRI studies of stroke should take frequency effects into account when measuring intrinsic brain activity.
High-intensity interval training: Modulating interval duration in overweight/obese men.
Smith-Ryan, Abbie E; Melvin, Malia N; Wingfield, Hailee L
2015-05-01
High-intensity interval training (HIIT) is a time-efficient strategy shown to induce various cardiovascular and metabolic adaptations. Little is known about the optimal tolerable combination of intensity and volume necessary for adaptations, especially in clinical populations. In a randomized controlled pilot design, we evaluated the effects of two types of interval training protocols, varying in intensity and interval duration, on clinical outcomes in overweight/obese men. Twenty-five men [body mass index (BMI) > 25 kg · m(2)] completed baseline body composition measures: fat mass (FM), lean mass (LM) and percent body fat (%BF) and fasting blood glucose, lipids and insulin (IN). A graded exercise cycling test was completed for peak oxygen consumption (VO2peak) and power output (PO). Participants were randomly assigned to high-intensity short interval (1MIN-HIIT), high-intensity interval (2MIN-HIIT) or control groups. 1MIN-HIIT and 2MIN-HIIT completed 3 weeks of cycling interval training, 3 days/week, consisting of either 10 × 1 min bouts at 90% PO with 1 min rests (1MIN-HIIT) or 5 × 2 min bouts with 1 min rests at undulating intensities (80%-100%) (2MIN-HIIT). There were no significant training effects on FM (Δ1.06 ± 1.25 kg) or %BF (Δ1.13% ± 1.88%), compared to CON. Increases in LM were not significant but increased by 1.7 kg and 2.1 kg for 1MIN and 2MIN-HIIT groups, respectively. Increases in VO2peak were also not significant for 1MIN (3.4 ml·kg(-1) · min(-1)) or 2MIN groups (2.7 ml · kg(-1) · min(-1)). IN sensitivity (HOMA-IR) improved for both training groups (Δ-2.78 ± 3.48 units; p < 0.05) compared to CON. HIIT may be an effective short-term strategy to improve cardiorespiratory fitness and IN sensitivity in overweight males.
International Nuclear Information System (INIS)
Lev, U; Prabhudesai, V; Natan, A; Bruner, B; Diner, A; Heber, O; Strasser, D; Schwalm, D; Silberberg, Y; Zajfman, D; Ben-Itzhak, I; Hua, J J; Esry, B D
2009-01-01
H 2 + photodissociation, induced by intense short laser pulses, was measured by a full 3D imaging system. We have conducted a series of experiments, in which we systematically changed the linear chirp, using a pulse shaper, and observed the kinetic energy release spectra(KER). Distinct differences in the KER spectra are observed both in peak positions and angular distribution for laser pulses with similar duration and intensity but opposite chirp sign.
The Noisiness of Low-Frequency One-Third Octave Bands of Noise. M.S. Thesis - Southampton Univ.
Lawton, B. W.
1975-01-01
This study examined the relative noisiness of low frequency one-third octave bands of noise bounded by the bands centered at 25 Hz and 200 Hz, with intensities ranging from 50 db sound pressure level (SPL) to 95 db SPL. The thirty-two subjects used a method-of-adjustment technique, producing comparison-band intensities as noisy as standard bands centered at 100 Hz and 200 Hz with intensities of 60 db SPL and 72 db SPL. Four contours of equal noisiness were developed for one-third octave bands, extending down to 25 Hz and ranging in intensity from approximately 58 db SPL to 86 db SPL. These curves were compared with the contours of equal noisiness of Kryter and Pearsons. In the region of overlap (between 50 Hz and 200 Hz) the agreement was good.
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L. Guicking
2010-04-01
Full Text Available We investigate wave properties of low-frequency magnetic field fluctuations in Venus' solar wind interaction region based on the measurements made on board the Venus Express spacecraft. The orbit geometry is very suitable to investigate the fluctuations in Venus' low-altitude magnetosheath and mid-magnetotail and provides an opportunity for a comparative study of low-frequency waves at Venus and Mars. The spatial distributions of the wave properties, in particular in the dayside and nightside magnetosheath as well as in the tail and mantle region, are similar to observations at Mars. As both planets do not have a global magnetic field, the interaction process of the solar wind with both planets is similar and leads to similar instabilities and wave structures. We focus on the spatial distribution of the wave intensity of the fluctuating magnetic field and detect an enhancement of the intensity in the dayside magnetosheath and a strong decrease towards the terminator. For a detailed investigation of the intensity distribution we adopt an analytical streamline model to describe the plasma flow around Venus. This allows displaying the evolution of the intensity along different streamlines. It is assumed that the waves are generated in the vicinity of the bow shock and are convected downstream with the turbulent magnetosheath flow. However, neither the different Mach numbers upstream and downstream of the bow shock, nor the variation of the cross sectional area and the flow velocity along the streamlines play probably an important role in order to explain the observed concentration of wave intensity in the dayside magnetosheath and the decay towards the nightside magnetosheath. But, the concept of freely evolving or decaying turbulence is in good qualitative agreement with the observations, as we observe a power law decay of the intensity along the streamlines. The observations support the assumption of wave convection through the magnetosheath, but
Energy Technology Data Exchange (ETDEWEB)
Potchen, E. J.; Bentley, R.; Gerth, W.; Hill, R. L.; Davis, D. O. [Washington University School Of Medicine, St. Louis, MO (United States)
1969-05-15
The use of freely diffusable inert radioactive gas as a washout indicator to measure regional cerebral blood flow has become a standardized kinetic procedure in many laboratories. Recent investigations with this technique have led us to conclude that we can reliably distinguish regional flow with perfusion against regional flow without perfusion from the early portion of the curve. Based on a detailed study of the early curve kinetics in patients with and without cerebral vascular disease we have defined the sampling duration necessary for application of the Anger gamma camera imaging process to regional changes in cerebral radioactivity. Using a standard camera and a small computer, a procedure has been developed and based upon entire field to determine the time of maximum height followed by analysis of the data in a matrix. This will permit a contour plot presentation of calculated regional cerebral blood flow in millilitres per 100 grams perfused brain per minute. In addition, we propose to augment this data by the display of regional non-perfusion blood flow versus regional cerebral flow with perfusion. Preliminary investigation on sampling duration, and Compton scattering were prerequisite to clinical scintigraphy of regional cerebral blood flow. In addition, the method of interface for the conventional Anger gamma camera to digital computers used in this procedure are discussed. Applications to further assess regional cerebral dynamics by scintigraphy are presented. (author)
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Jung Ah Lee
2017-03-01
Full Text Available Introduction: The prevalence of adolescent electronic cigarette (e-cigarette use has increased in most countries. This study aims to determine the relation between the frequency of e-cigarette use and the frequency and intensity of cigarette smoking. Additionally, the study evaluates the association between the reasons for e-cigarette use and the frequency of its use. Materials and Methods: Using the 2015 Korean Youth Risk Behavior Web-Based Survey, we included 6655 adolescents with an experience of e-cigarette use who were middle and high school students aged 13–18 years. We compared smoking experience, the frequency and intensity of cigarette smoking, and the relation between the reasons for e-cigarette uses and the frequency of e-cigarette use. Results: The prevalence of e-cigarette ever and current (past 30 days users were 10.1% and 3.9%, respectively. Of the ever users, approximately 60% used e-cigarettes not within 1 month. On the other hand, 8.1% used e-cigarettes daily. The frequent and intensive cigarette smoking was associated with frequent e-cigarette uses. The percentage of frequent e-cigarette users (≥10 days/month was 3.5% in adolescents who did not smoke within a month, but 28.7% among daily smokers. Additionally, it was 9.1% in smokers who smoked less than 1 cigarette/month, but 55.1% in smokers who smoked ≥20 cigarettes/day. The most common reason for e-cigarette use was curiosity (22.9%, followed by the belief that they are less harmful than conventional cigarettes (18.9%, the desire to quit smoking (13.1%, and the capacity for indoor use (10.7%. Curiosity was the most common reason among less frequent e-cigarette users; however, the desire to quit smoking and the capacity for indoor use were the most common reasons among more frequent users. Conclusions: Results showed a positive relation between frequency or intensity of conventional cigarette smoking and the frequency of e-cigarette use among Korean adolescents, and
Singh, Jitendra; Hari, Vittal; Sharma, Tarul; Karmakar, Subhankar; Ghosh, Subimal
2016-04-01
The statistical assumption of stationarity in hydrologic extreme time/event series has been relied heavily in frequency analysis. However, due to the analytically perceivable impacts of climate change, urbanization and concomitant land use pattern, assumption of stationarity in hydrologic time series will draw erroneous results, which in turn may affect the policy and decision-making. Past studies provided sufficient evidences on changes in the characteristics of Indian monsoon precipitation extremes and further it has been attributed to climate change and urbanization, which shows need of nonstationary analysis on the Indian monsoon extremes. Therefore, a comprehensive multivariate nonstationary frequency analysis has been conducted for the entire India to identify the precipitation characteristics (intensity, duration and depth) responsible for significant nonstationarity in the Indian monsoon. We use 1o resolution of precipitation data for a period of 1901-2004, in a Generalized Additive Model for Location, Scale and Shape (GAMLSS) framework. A cluster of GAMLSS models has been developed by considering nonstationarity in different combinations of distribution parameters through different regression techniques, and the best-fit model is further applied for bivariate analysis. A population density data has been utilized to identify the urban, urbanizing and rural regions. The results showed significant differences in the stationary and nonstationary bivariate return periods for the urbanizing grids, when compared to urbanized and rural grids. A comprehensive multivariate analysis has also been conducted to identify the precipitation characteristics particularly responsible for imprinting signature of nonstationarity.
Zhang, Yu-Yu; Zhu, Wen-Xing; Cao, Guo-Hong; Cui, Xi-Yun; Ai, Hong-Bin
2009-09-01
Restraint water-immersion stress (RWIS) can induce anxiety, hypothermia, and severe vagally-mediated gastric dysfunction. The present work explored the effects of different durations of RWIS on neuronal activities of the forebrain by c-Fos expression in conscious rats exposed to RWIS for 0, 30, 60, 120, or 180 min. The peak of c-Fos induction was distinct for different forebrain regions. The most intense c-Fos induction was always observed in the supraoptic nucleus (SON), and then in the hypothalamic paraventricular nucleus (PVN), posterior cortical amygdaloid nucleus (PCoA), central amygdaloid nucleus (CeA), and medial prefrontal cortex (mPFC). Moreover, body temperature was reduced to the lowest degree after 60 min of RWIS, and the gastric lesions tended to gradually worsen with the prolonging of RWIS duration. These data strongly suggest that these nuclei participate in the organismal response to RWIS to different degrees, and may be involved in the hypothermia and gastric lesions induced by RWIS.
Distortion-product otoacoustic emission growth curves in neonates
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Tania Alves Barbosa
2014-12-01
Full Text Available Background: The recording of otoacoustic emissions (OAE enabled us to prove that the cochlea is able not only to receive sounds but also to produce acoustic energy. Through the use of distortion-product otoacoustic emission measurements, the growth of the response was seen according to the intensity of the sound stimulus presented (growth curve. Objective: to determine the thresholds for the emergence of distortion-product otoacoustic emissions (DPOAE on frequencies of 2000 and 4000 Hz with a stimulus varying from 20 to 65dB SPL, and to establish the slope values obtained in the growth curves. Methods: 39 neonates aged 5 to 28 days without risk indicators of hearing loss were studied. The DPOAE growth curves were obtained on the frequencies from 2000 Hz and 4000 Hz with a level of intensity ranging from 20 to 65dB SPL divided into two paradigms (20 to 40dB SPL and 40-65dB SPL. Results: there was a statistically significant difference in the thresholds for the emergence of DPOAE depending on the criteria used. The thresholds were on average higher at 4000 Hz than 2000 Hz and the slope was higher on average at 2000 Hz than 4000 Hz, although not statistically significant in either case. Conclusion: the thresholds were on average 30dB SPL at 2000Hz and 35dB SPL at 4000Hz. The slope values varied between 3 and 4 on average, reaching 15 in some cases.
Teixeira-Coelho, Francisco; Fonseca, Cletiana Gonçalves; Barbosa, Nicolas Henrique Santos; Vaz, Filipe Ferreira; Cordeiro, Letícia Maria de Souza; Coimbra, Cândido Celso; Pires, Washington; Soares, Danusa Dias; Wanner, Samuel Penna
2017-01-01
This study investigated the effects of manipulating the load components of aerobic training sessions on the physical performance of rats. To achieve this purpose, adult male Wistar rats were divided into four groups: an untrained control (CON) group and training groups with a predominant overload in intensity (INT) or duration (DUR) or alternating and similar overloads in intensity and duration (ID). Prior to, during, and after 8 weeks of the control or training protocols, the performance of the rats (evaluated by their workload) was determined during fatiguing, incremental-speed treadmill running. Two additional incremental running tests were performed prior to and at the end of the protocols to measure the peak rate of oxygen consumption (VO2peak). As expected, the rats in the trained groups exhibited increased performance, whereas the untrained rats showed stable performance throughout the 8 weeks. Notably, the performance gain exhibited by the DUR rats reached a plateau after the 4th week. This plateau was not present in the INT or ID rats, which exhibited increased performance at the end of training protocol compared with the DUR rats. None of the training protocols changed the VO2peak values; however, these values were attained at faster speeds, which indicated increased running economy. In conclusion, our findings demonstrate that the training protocols improved the physical performance of rats, likely resulting from enhanced running economy. Furthermore, compared with overload in duration, overload in the intensity of training sessions was more effective at inducing performance improvements across the 8 weeks of the study.
TCIQ: An identification by intensity and frequency of potent testing cues in science
Kermis, William J.
Everyone experiences some anxiety while taking an examination. High-test-anxious (HTA) and low-test-anxious (LTA) students are described by two characteristic differences: frequency and intensity of anxious responses and attentional direction to testing cues. The purposes of this study were threefold: (1) to report potent testing cues (i.e., 90% response agreement for both intensity and frequency) that were identified by HTA and LTA students; (2) to report differences between HTA and LTA students for frequencies and intensities of responses to testing cues; and (3) to report differences between HTA and LTA students of attentional direction to testing cues. A pool of 396 males and females who were enrolled in physical geology completed the State-Trait Anxiety Inventory. A random sample consisting of 93 HTA and 40 LTA subjects completed the Test Cues Identification Questionnaire (TCIQ). The TCIQ consists of 28 disruptive items and 27 helpful items. Subjects responded with both frequency and intensity ratings for all of the 55 items in the TCIQ. Results revealed that 22 items were viewed by subjects as potent testing cues. Empirical evidence obtained did not support previous theoretical reports of differences between HTA and LTA students for either frequency and intensity of anxious responses or attentional direction to the set of disruptive and helpful testing cues. Although test anxiousness did not appear to be associated with those two characteristics differences, a discriminant analysis revealed 24 items in the TCIQ which significantly, 2 (24) = 47.59, p < 0.004, separated HTA and LTA subjects responses. Apparently, HTA and LTA students differ in their responses to specific disruptive and helpful cues but not in their responses to the set of testing cues as was previously postulated.
Seasonal anomalies in electricity intensity across Chinese regions
International Nuclear Information System (INIS)
Herrerias, M.J.
2013-01-01
Highlights: ► We analyze seasonal anomalies in electricity intensity in China. ► Regional and time dimensions are investigated from 2003 to 2009. ► Results suggest that seasonality is stochastic. ► We find four main effects: Summer, Winter, Spring and Lunar New Year effects. ► Differences are observed between northern regions and east-south of China. - Abstract: This paper provides evidence on the relevance of modeling the seasonal nature of electricity intensity across Chinese regions in a suitable manner with monthly data from 2003 to 2009. In contrast to previous works, this study relaxes the assumption of deterministic seasonality, allowing for time and regional variation in the Chinese economy. In doing so, unobserved-components models are used to analyze the type of seasonality – stochastic or deterministic – that prevails. Regional differences in the seasonal patterns and their evolution over time are also examined. Results provide new empirical evidence on the stochastic nature of electricity intensity in the majority of the provinces. In addition, we find four main effects as regards seasonal patterns: (i) Lunar New Year, (ii) Summer, (iii) Spring, and (iv) Winter effects. In the first two effects seasonality becomes positive, thus indicating that electricity intensity increases, and the last two are negative, showing improvements in the use of electricity per unit of output. However, differences are observed between northern regions and the east-south of China. In addition, once we control our estimates for temperature and prices, no significant differences are seen in the results. Conclusions from this analysis are useful for empirical modeling in the energy-economics literature, and also for designing energy policies to improve the efficiency of the use of energy resources across Chinese regions
Gao, Yanhui; Liu, Li; Chen, Sidong
2013-01-01
Background Although previous meta-analyses have suggested an association between aspirin use and risk of gastric cancer, current evidence is inconsistent. Additionally, it remains unclear whether there are frequency-risk and duration-risk relationships and if a threshold of effect exists. Methods We identified studies by searching MEDLINE and PUBMED databases and reviewing relevant articles. We derived the summary risk estimates using fixed-effects or random-effects model based on homogeneity analysis. The dose-response meta-analysis was performed by linear trend regression and restricted cubic spline regression. Potential heterogeneity was tested using the Q statistic and quantified with the I 2 statistic. Subgroup analyses and Galbraith plots were used to explore the potential sources of heterogeneity. Publication bias was evaluated with funnel plots and quantified by the Begg's and Egger's test. Results Fifteen studies were included in this meta-analysis. There was an overall 29% reduced risk of gastric cancer corresponding to aspirin use (RR = 0.71, 95% CI 0.60–0.82). We found there are nonlinear frequency-risk and linear duration-risk relations between aspirin use and gastric cancer. A monotonically decreasing relation was observed only for low-frequency (≤4.5 times/week) aspirin intake (10% decreased risk for once/week, 19% for twice/week and 29% for 4.5 times/week), and the frequency threshold of aspirin use is 4.5 times per week. Regarding those with duration of aspirin use, there was a tendency towards stronger risk reduction of gastric cancer for longer aspirin use (10% decreased risk for 4 years, 19% for 8 years and 28% for 12 years), and no duration threshold was observed. Conclusion Our findings suggest that long-term (≥4 years) and low-frequency (1–4.5 times per week) aspirin use is associated with a statistically significant, dose-dependent reduction in the risk of gastric cancer. PMID:23936269
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Xiaohua Ye
Full Text Available BACKGROUND: Although previous meta-analyses have suggested an association between aspirin use and risk of gastric cancer, current evidence is inconsistent. Additionally, it remains unclear whether there are frequency-risk and duration-risk relationships and if a threshold of effect exists. METHODS: We identified studies by searching MEDLINE and PUBMED databases and reviewing relevant articles. We derived the summary risk estimates using fixed-effects or random-effects model based on homogeneity analysis. The dose-response meta-analysis was performed by linear trend regression and restricted cubic spline regression. Potential heterogeneity was tested using the Q statistic and quantified with the I (2 statistic. Subgroup analyses and Galbraith plots were used to explore the potential sources of heterogeneity. Publication bias was evaluated with funnel plots and quantified by the Begg's and Egger's test. RESULTS: Fifteen studies were included in this meta-analysis. There was an overall 29% reduced risk of gastric cancer corresponding to aspirin use (RR = 0.71, 95% CI 0.60-0.82. We found there are nonlinear frequency-risk and linear duration-risk relations between aspirin use and gastric cancer. A monotonically decreasing relation was observed only for low-frequency (≤4.5 times/week aspirin intake (10% decreased risk for once/week, 19% for twice/week and 29% for 4.5 times/week, and the frequency threshold of aspirin use is 4.5 times per week. Regarding those with duration of aspirin use, there was a tendency towards stronger risk reduction of gastric cancer for longer aspirin use (10% decreased risk for 4 years, 19% for 8 years and 28% for 12 years, and no duration threshold was observed. CONCLUSION: Our findings suggest that long-term (≥4 years and low-frequency (1-4.5 times per week aspirin use is associated with a statistically significant, dose-dependent reduction in the risk of gastric cancer.
Pool, Sandra; Viviroli, Daniel; Seibert, Jan
2017-11-01
Applications of runoff models usually rely on long and continuous runoff time series for model calibration. However, many catchments around the world are ungauged and estimating runoff for these catchments is challenging. One approach is to perform a few runoff measurements in a previously fully ungauged catchment and to constrain a runoff model by these measurements. In this study we investigated the value of such individual runoff measurements when taken at strategic points in time for applying a bucket-type runoff model (HBV) in ungauged catchments. Based on the assumption that a limited number of runoff measurements can be taken, we sought the optimal sampling strategy (i.e. when to measure the streamflow) to obtain the most informative data for constraining the runoff model. We used twenty gauged catchments across the eastern US, made the assumption that these catchments were ungauged, and applied different runoff sampling strategies. All tested strategies consisted of twelve runoff measurements within one year and ranged from simply using monthly flow maxima to a more complex selection of observation times. In each case the twelve runoff measurements were used to select 100 best parameter sets using a Monte Carlo calibration approach. Runoff simulations using these 'informed' parameter sets were then evaluated for an independent validation period in terms of the Nash-Sutcliffe efficiency of the hydrograph and the mean absolute relative error of the flow-duration curve. Model performance measures were normalized by relating them to an upper and a lower benchmark representing a well-informed and an uninformed model calibration. The hydrographs were best simulated with strategies including high runoff magnitudes as opposed to the flow-duration curves that were generally better estimated with strategies that captured low and mean flows. The choice of a sampling strategy covering the full range of runoff magnitudes enabled hydrograph and flow-duration curve
Bogaard, Thom; Greco, Roberto
2018-01-01
Many shallow landslides and debris flows are precipitation initiated. Therefore, regional landslide hazard assessment is often based on empirically derived precipitation intensity-duration (ID) thresholds and landslide inventories. Generally, two features of precipitation events are plotted and labeled with (shallow) landslide occurrence or non-occurrence. Hereafter, a separation line or zone is drawn, mostly in logarithmic space. The practical background of ID is that often only meteorological information is available when analyzing (non-)occurrence of shallow landslides and, at the same time, it could be that precipitation information is a good proxy for both meteorological trigger and hydrological cause. Although applied in many case studies, this approach suffers from many false positives as well as limited physical process understanding. Some first steps towards a more hydrologically based approach have been proposed in the past, but these efforts received limited follow-up.Therefore, the objective of our paper is to (a) critically analyze the concept of precipitation ID thresholds for shallow landslides and debris flows from a hydro-meteorological point of view and (b) propose a trigger-cause conceptual framework for lumped regional hydro-meteorological hazard assessment based on published examples and associated discussion. We discuss the ID thresholds in relation to return periods of precipitation, soil physics, and slope and catchment water balance. With this paper, we aim to contribute to the development of a stronger conceptual model for regional landslide hazard assessment based on physical process understanding and empirical data.
Hakobyan, H. L.; Beskin, V. S.; Philippov, A. A.
2017-08-01
Our previous paper outlined the general aspects of the theory of radio light curve and polarization formation for pulsars. We predicted the one-to-one correspondence between the tilt of the linear polarization position angle of the the circular polarization. However, some of the radio pulsars indicate a clear deviation from that correlation. In this paper, we apply the theory of the radio wave propagation in the pulsar magnetosphere for the analysis of individual effects leading to these deviations. We show that within our theory the circular polarization of a given mode can switch its sign, without the need to introduce a new radiation mode or other effects. Moreover, we show that the generation of different emission modes on different altitudes can explain pulsars, that presumably have the X-O-X light-curve pattern, different from what we predict. General properties of radio emission within our propagation theory are also discussed. In particular, we calculate the intensity patterns for different radiation altitudes and present light curves for different observer viewing angles. In this context we also study the light curves and polarization profiles for pulsars with interpulses. Further, we explain the characteristic width of the position angle curves by introducing the concept of a wide emitting region. Another important feature of radio polarization profiles is the shift of the position angle from the centre, which in some cases demonstrates a weak dependence on the observation frequency. Here we demonstrate that propagation effects do not necessarily imply a significant frequency-dependent change of the position angle curve.
Energy Technology Data Exchange (ETDEWEB)
Feister, S., E-mail: feister.7@osu.edu; Orban, C. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Nees, J. A. [Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Center for Ultra-Fast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Morrison, J. T. [Fellow, National Research Council, Washington, D.C. 20001 (United States); Frische, K. D. [Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Chowdhury, E. A. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Intense Energy Solutions, LLC., Plain City, Ohio 43064 (United States); Roquemore, W. M. [Air Force Research Laboratory, Dayton, Ohio 45433 (United States)
2014-11-15
Ultra-intense laser-matter interaction experiments (>10{sup 18} W/cm{sup 2}) with dense targets are highly sensitive to the effect of laser “noise” (in the form of pre-pulses) preceding the main ultra-intense pulse. These system-dependent pre-pulses in the nanosecond and/or picosecond regimes are often intense enough to modify the target significantly by ionizing and forming a plasma layer in front of the target before the arrival of the main pulse. Time resolved interferometry offers a robust way to characterize the expanding plasma during this period. We have developed a novel pump-probe interferometry system for an ultra-intense laser experiment that uses two short-pulse amplifiers synchronized by one ultra-fast seed oscillator to achieve 40-fs time resolution over hundreds of nanoseconds, using a variable delay line and other techniques. The first of these amplifiers acts as the pump and delivers maximal energy to the interaction region. The second amplifier is frequency shifted and then frequency doubled to generate the femtosecond probe pulse. After passing through the laser-target interaction region, the probe pulse is split and recombined in a laterally sheared Michelson interferometer. Importantly, the frequency shift in the probe allows strong plasma self-emission at the second harmonic of the pump to be filtered out, allowing plasma expansion near the critical surface and elsewhere to be clearly visible in the interferograms. To aid in the reconstruction of phase dependent imagery from fringe shifts, three separate 120° phase-shifted (temporally sheared) interferograms are acquired for each probe delay. Three-phase reconstructions of the electron densities are then inferred by Abel inversion. This interferometric system delivers precise measurements of pre-plasma expansion that can identify the condition of the target at the moment that the ultra-intense pulse arrives. Such measurements are indispensable for correlating laser pre-pulse measurements
The Frequency and Duration of Uterine Contractions during Labour
African Journals Online (AJOL)
1974-04-17
Apr 17, 1974 ... n-e;.l. Fig. 12. Indian primigravidas: duration of contractions. Fig. 11. Indian multiparas: duration of contractions. Fig. 10. Black primigravidas (all ages): duration of con- tractiom. Indian multiparas: Fig. 11 shows the duration of con- tractions in labour of Indian multiparas studied. Again, the pattern is similar to ...
Measurement of high-power microwave pulse under intense ...
Indian Academy of Sciences (India)
Abstract. KALI-1000 pulse power system has been used to generate single pulse nanosecond duration high-power microwaves (HPM) from a virtual cathode oscillator. (VIRCATOR) device. HPM power measurements were carried out using a transmitting– receiving system in the presence of intense high frequency (a few ...
A controlled evaluation of oral screen effects on intra-oral pressure curve characteristics.
Knösel, Michael; Jung, Klaus; Kinzinger, Gero; Bauss, Oskar; Engelke, Wilfried
2010-10-01
The purpose of this study was to quantify the impact of oral screen (OS) application on intra-oral pressure characteristics in three malocclusion groups. Fifty-six randomly recruited participants (26 males and 30 females) who met the inclusion criteria of either an Angle Class I occlusal relationships or Angle Class II1 or II2 malocclusions, were assigned by dentition to group I (n = 31), group II1 (n = 12), or group II2 (n = 13). Two 3 minute periods of intra-oral pressure monitoring were conducted on each participant, using two different oral end fittings connected to a piezo-resistive relative pressure sensor: (1) a flexible OS and (2) a small-dimensioned air-permeable end cap (EC), which was placed laterally in the premolar region, thus recording intra-oral pressure independent of the influence of the OS. Pressure curve characteristics for both periods and between the malocclusion groups were evaluated with reference to the frequency of swallowing peaks, duration, and altitude of negative pressure plateau phases and the area under the pressure curve. Statistical analysis was undertaken using analysis of variance (ANOVA), the Wilcoxon Mann-Whitney test, and spearman correlation coefficient. A median number of two peaks (median height -20.9 mbar) and three plateau phases (median height of -2.3 mbar) may be regarded as normative for normal occlusion subjects during a 3 minute period, at rest. OS application raised the median average duration and height of intra-oral negative pressure plateau phases in the II1 subjects, exceeding those of group I, but less than the plateau duration in group II2. Median peak heights were distinctively lower in groups I and II1 during OS application. It is concluded that additional training for extension of intra-oral pressure phases may be a promising approach to pre-orthodontic Class II division 1 treatment.
Sobol, N. V.; Gabbasova, I. M.; Komissarov, M. A.
2017-09-01
The effect of rainfall intensity on the erosion of residual calcareous agrogray soils and clay-illuvial agrochernozems in the Southern Cis-Ural region on slopes of different inclination and vegetation type has been studied by simulating with a small-size sprinkler. It has been shown that soil loss linearly depends on rainfall intensity (2, 4, and 6 mm/min) and slope inclination (3° and 7°). When the rainfall intensity and duration, and the slope inclination increase, soil loss by erosion from agrogray soils increases higher than from agrochernozems. On the plowland with a slope of 3°, runoff begins 12, 10, and 5 min, on the average, after the beginning of rains at these intensities. When the slope increases to 7°, runoff begins earlier by 7, 6, and 4 min, respectively. After the beginning of runoff and with its increase by 1 mm, the soil loss from slopes of 3° and 7° reaches 4.2 and 25.7 t/ha on agrogray soils and 1.4 and 4.7 t/ha on agrochernozems, respectively. Fallow soils have higher erosion resistance, and the soil loss little depends on the slope gradient: it gradually increases to 0.3-1.0 t/ha per 1 mm of runoff with increasing rainfall intensity and duration. The content of physical clay in eroded material is higher than in the original soils. Fine fractions prevail in this material, which increases their humus content. The increase in rainfall intensity and duration to 4 and 6 mm/min results in the entrapment of coarse silt and sand by runoff.
Cambras, Trinitat; Díez-Noguera, Antoni
2012-07-01
Circadian rhythms are strongly influenced by light intensity, the effects of which may persist beyond the duration of light exposure (aftereffects). Here, the authors constructed period-illuminance curves for the motor activity circadian rhythm of male and female rats by recording the effects of a series of small upward and downward steps in light intensity (illuminance ranging between .01 lux of dim red light and 1 lux of white light) on their activity. In all cases, stepwise changes were made in five logarithmic steps (irradiance: dim red light: .692 µW/cm(2) and white light: .006, .016, .044, .12, and .315 µW/cm(2), corresponding, respectively, to .02, .05, .14, .13, and 1 lux measured at cage level), with changes in intensity every 2 wks. One group of rats (DLD) started in dim red light, moved up to 1 lux white light, and then back down to the original light intensity. Another group (LDL) started at 1 lux, moved down to .01 lux, and then back up to the original intensity. Motor activity data were recorded throughout the experiment and tau values, the percentage of variance explained by the rhythm, and the mean motor activity for each stage and group were calculated. The results show differences in the dynamics of tau values between the DLD and LDL groups and between males and females. In the LDL group, the tau values of both males and females were dependent on light intensity, and were similar for the forward and backward transitions. In other words, no aftereffects were found, and no differences were detected between males and females. In the DLD group, however, differences were found between males and females. Males had a tau value of 24 h 20 min under dim red light, 25 h 40 min under 1 lux, and 24 h 50 min on return to dim red light. It is noticeable that the tau values of the backward branch of the illuminance curve contradicted classical predictions, since at .38 and .14 lux the tau values were shorter than those found under the same intensities after
Removing the impact of water abstractions on flow duration curves
Masoero, Alessandro; Ganora, Daniele; Galeati, Giorgio; Laio, Francesco; Claps, Pierluigi
2015-04-01
on few easy-access parameters, of correction of the water abstraction impact. The model, based on an exponential form of the river Flow Duration Curve (FDC), allows completely analytical solutions. Hence the method can be applied extensively. This is particularly relevant when working on a general outlook on water resources (regional or basin scale), given the high number of water abstractions that should be considered. The correction method developed is based on only two hard data that can be easily found: i) the design maximum discharge of the water intake and ii) the days of exercise, between a year. Following the same correction hypothesis also the abstracted discharge statistics have been reconstructed analytically and combined with the statistics of the receiving reach, that can be different from the original one. This information can be useful when we are assessing water availability in a river network interconnected by derivation channels. The goodness of the correction method proposed is proven by the application to a case study in North-West Italy, along a second order tributary of the Po River. Flow values recorded at the river gauge station were affected, significantly, by the presence of a 5 MW hydropower plant. Knowing the amount of water abstracted daily by the power plant we are able to reconstruct, empirically, the natural discharge on the river and compare its main statistics with the ones computed analytically using the proposed correction model. An extremely low difference between empirical and analytical reconstructed mean discharge and L-moment of variation was founded. Also, the importance of the day of exercise information was highlighted. The correction proposed in this work is able to give a correct indication of the non-impacted natural streamflows characteristics, especially in alpine regions where water abstraction impact is a main issue.
[Micro-simulation of firms' heterogeneity on pollution intensity and regional characteristics].
Zhao, Nan; Liu, Yi; Chen, Ji-Ning
2009-11-01
In the same industrial sector, heterogeneity of pollution intensity exists among firms. There are some errors if using sector's average pollution intensity, which are calculated by limited number of firms in environmental statistic database to represent the sector's regional economic-environmental status. Based on the production function which includes environmental depletion as input, a micro-simulation model on firms' operational decision making is proposed. Then the heterogeneity of firms' pollution intensity can be mechanically described. Taking the mechanical manufacturing sector in Deyang city, 2005 as the case, the model's parameters were estimated. And the actual COD emission intensities of environmental statistic firms can be properly matched by the simulation. The model's results also show that the regional average COD emission intensity calculated by the environmental statistic firms (0.002 6 t per 10 000 yuan fixed asset, 0.001 5 t per 10 000 yuan production value) is lower than the regional average intensity calculated by all the firms in the region (0.003 0 t per 10 000 yuan fixed asset, 0.002 3 t per 10 000 yuan production value). The difference among average intensities in the six counties is significant as well. These regional characteristics of pollution intensity attribute to the sector's inner-structure (firms' scale distribution, technology distribution) and its spatial deviation.
Directory of Open Access Journals (Sweden)
A. M. Hashemi
2000-01-01
Full Text Available Regionalized and at-site flood frequency curves exhibit considerable variability in their shapes, but the factors controlling the variability (other than sampling effects are not well understood. An application of the Monte Carlo simulation-based derived distribution approach is presented in this two-part paper to explore the influence of climate, described by simulated rainfall and evapotranspiration time series, and basin factors on the flood frequency curve (ffc. The sensitivity analysis conducted in the paper should not be interpreted as reflecting possible climate changes, but the results can provide an indication of the changes to which the flood frequency curve might be sensitive. A single site Neyman Scott point process model of rainfall, with convective and stratiform cells (Cowpertwait, 1994; 1995, has been employed to generate synthetic rainfall inputs to a rainfall runoff model. The time series of the potential evapotranspiration (ETp demand has been represented through an AR(n model with seasonal component, while a simplified version of the ARNO rainfall-runoff model (Todini, 1996 has been employed to simulate the continuous discharge time series. All these models have been parameterised in a realistic manner using observed data and results from previous applications, to obtain ‘reference’ parameter sets for a synthetic case study. Subsequently, perturbations to the model parameters have been made one-at-a-time and the sensitivities of the generated annual maximum rainfall and flood frequency curves (unstandardised, and standardised by the mean have been assessed. Overall, the sensitivity analysis described in this paper suggests that the soil moisture regime, and, in particular, the probability distribution of soil moisture content at the storm arrival time, can be considered as a unifying link between the perturbations to the several parameters and their effects on the standardised and unstandardised ffcs, thus revealing the
Relationships between the intensity and duration of Peltier heat stimulation and pain magnitude.
Vierck, Charles J; Mauderli, Andre P; Riley, Joseph L
2013-03-01
Ramp-and-hold heat stimulation with a Peltier thermode is a standard procedure for quantitative sensory testing of human pain sensitivity. Because myelinated and unmyelinated nociceptive afferents respond preferentially to changing and steady temperatures, respectively, ramp-and-hold heat stimulation could assess processing of input from A-delta nociceptors early and C nociceptors late during prolonged thermal stimulation. In order to evaluate the progression from dynamic change to a steady temperature during prolonged Peltier stimulation, recordings of temperatures at the probe-skin interface were obtained. First, recordings of temperature during contact-and-hold stimulation (solenoid powered delivery of a preheated thermode to the skin) provided an evaluation of heat dissipation from the beginning of stimulation, uncontaminated by ramping. The heat-sink effect lasted up to 8 s and accounted in part for a slow increase in pain intensity for stimulus durations of 1-16 s and stimulus intensities of 43-59 °C. Recordings during longer periods of stimulation showed that feedback-controlled Peltier stimulation generated oscillations in temperature that were tracked for up to 75 s by subjects' continuous ratings of pain. During 120-s trials, sensitization of pain was observed over 45 s after the oscillations subsided. Thus, long-duration stimulation can be utilized to evaluate sensitization, presumably of C nociception, when not disrupted by oscillations in thermode temperature (e.g., those inherent to feedback control of Peltier stimulation). In contrast, sensitization was not observed during 130.5 s of stimulation with alternately increasing and decreasing temperatures that repeatedly activated A-delta nociceptors.
Trace, Sara E.; Thornton, Laura M.; Root, Tammy L.; Mazzeo, Suzanne E.; Lichtenstein, Paul; Pedersen, Nancy L.; Bulik, Cynthia M.
2011-01-01
Objective We assessed the impact of reducing the binge eating frequency and duration thresholds on the diagnostic criteria for bulimia nervosa (BN) and binge eating disorder (BED). Method We estimated the lifetime population prevalence of BN and BED in 13,295 female twins from the Swedish Twin study of Adults: Genes and Environment employing a range of frequency and duration thresholds. External validation (risk to co-twin) was used to investigate empirical evidence for an optimal binge eating frequency threshold. Results The lifetime prevalence estimates of BN and BED increased linearly as the frequency criterion decreased. As the required duration increased, the prevalence of BED decreased slightly. Discontinuity in co-twin risk was observed in BN between at least four times per month and at least five times per month. This model could not be fit for BED. Discussion The proposed changes to the DSM-5 binge eating frequency and duration criteria would allow for better detection of binge eating pathology without resulting in a markedly higher lifetime prevalence of BN or BED. PMID:21882218
Trace, Sara E; Thornton, Laura M; Root, Tammy L; Mazzeo, Suzanne E; Lichtenstein, Paul; Pedersen, Nancy L; Bulik, Cynthia M
2012-05-01
We assessed the impact of reducing the binge eating frequency and duration thresholds on the diagnostic criteria for bulimia nervosa (BN) and binge eating disorder (BED). We estimated the lifetime population prevalence of BN and BED in 13,295 female twins from the Swedish Twin study of Adults: Genes and Environment employing a range of frequency and duration thresholds. External validation (risk to cotwin) was used to investigate empirical evidence for an optimal binge eating frequency threshold. The lifetime prevalence estimates of BN and BED increased linearly as the frequency criterion decreased. As the required duration increased, the prevalence of BED decreased slightly. Discontinuity in cotwin risk was observed in BN between at least four times per month and at least five times per month. This model could not be fit for BED. The proposed changes to the DSM-5 binge eating frequency and duration criteria would allow for better detection of binge eating pathology without resulting in a markedly higher lifetime prevalence of BN or BED. Copyright © 2011 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Lichun Xiong
2017-05-01
Full Text Available The Beijing-Tianjin-Hebei Region Integration Plan is one of the most important national strategies in China promoting regional economic development. The environmental problems in this region, however, especially air pollution and contaminated groundwater, have enormous influence on the people’s health while also causing economic loss. Therefore, this study aims to analyze the pattern of its environmental and economic development. Panel data in the period 2004–2014 are used to establish an advanced model of the Environmental Kuznets Curve. The results indicate that the economic growth and environmental pollution of Beijing-Tianjin-Hebei region do not completely meet the Environment Kuznets Curve assumptions. The discharge volume of industrial wastewater and economic growth reflect a wave-type relation. The sulfur dioxide discharge volume and economic growth reflect a U-shaped relation; the generated volume of industrial solid wastes and economic growth reflect a reversed N-shaped relation, which is in accordance with the Environmental Kuznets Curve characteristics at the second inflection point. The variables added value of the secondary industry, population size and raw coal consumption volume have a significant positive influence on the discharge of various environmental pollutants in Beijing-Tianjin-Hebei region. The analysis provides policy recommendations for the government to develop regional economic and environmental protection policies.
Energy intensity, CO{sub 2} emissions and the environmental Kuznets curve. The Spanish case
Energy Technology Data Exchange (ETDEWEB)
Roca, J. [Universitat de Barcelona (Spain). Dpt. Teoria Economica; Alcantara, V. [Universitat Autonoma de Barcelona (Spain). Dpt. Economia Aplicada
2001-06-01
This article analyses the role of energy intensity and the relationship between CO{sub 2} emissions and primary energy in order to explain the evolution of CO{sub 2} emissions by unit of real GDP. It also distinguishes two different meanings of CO{sub 2} emissions Kuznets curve hypothesis: the weak and the strong sense. It considers the case of Spain in the period 1972-1997 as an example in which there is not any evidence supporting this hypothesis in either sense. (author)
Directory of Open Access Journals (Sweden)
S Karbandi
2016-01-01
Full Text Available BACKGROUND AND OBJECTIVE: Approximately 80% of premature infants are diagnosed with icterus, most of whom are treated by phototherapy. Given the adverse effects of this treatment on neonates, minimizing the duration of phototherapy seems to be necessary. This study aimed to evaluate the effects of massage on the duration of phototherapy in premature infants admitted to neonatal intensive care units. METHODS: This clinical trial was performed on premature infants admitted to the neonatal intensive care unit of Qaem Hospital of Mashhad, Iran, in 2011. The infants were randomly divided into intervention (n=30 and control (n=30 groups. The infants of both groups were similar in terms of weight, age, and the level of bilirubin. The intervention group received massage therapy (including massage and passive movements of the body parts on a daily basis for three 15-minute courses at three consecutive hours for five days. The control group received the routine care and phototherapy. After the intervention, the two groups were compared in terms of duration of phototherapy and level of transcutaneous bilirubin. FINDINGS: The mean duration of phototherapy in the intervention and control groups was 80.8±61.58 and 112.8±75.45 hours, respectively. However, this difference was not statistically significant. On the fifth day of the intervention, the level of transcutaneous bilirubin was 9.7 and 8.1 mg/dl in the intervention and control groups, respectively, this difference was not significant as well. CONCLUSION: Massage can be used as an effective method alongside with phototherapy to minimize the duration of phototherapy for premature healthy infants in clinically stable conditions.
Curved Radio Spectra of Weak Cluster Shocks
Kang, Hyesung; Ryu, Dongsu
2015-08-01
In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.
African Journals Online (AJOL)
Anireh UC
forecasting of relevant hydraulic structures in Calabar. The logarithmic model is a two-parameter form of IDF equation. ... [16] for intensities duration-frequency curves for ungauged sites. ..... (Table 2). A similar trend was also observed between.
Tanik, Nermin; Serin, Halil Ibrahim; Celikbilek, Asuman; Inan, Levent Ertugrul; Gundogdu, Fatma
2015-11-15
Multiple sclerosis (MS) is a neuroinflammatory and neurodegenerative disease that progresses to axonal loss and demyelinization. Olfactory dysfunction in patients with MS has been reported frequently. We were interested in the associations of olfactory bulb (OB) and olfactory sulcus depth (OSD) with disease duration and attack frequency. We included 25 patients with MS and 30 age- and sex-matched controls in this study. The Expanded Disability Status Scale, Beck Depression Inventory, and Mini Mental State Examination were applied. OB, OSD, and magnetic resonance imaging plaque numbers were calculated. OB volume and OSD in patients with MS were significantly lower than those in the control group (right and left OB: p<0.001; right OSD: p=0.001; and left OSD: p=0.039). Disease duration was negatively correlated with right and left OB volume (right OB: r=-0.434, p=0.030 and left OB: r=-0.518, p=0.008). Attack frequency was negatively correlated with left OB volume and left OSD (left OB: r=-0.428, p=0.033 and left OSD: r=-0.431, p=0.032). The OB and OSD were atrophied significantly in patients with MS, and this was correlated with disease duration and attack frequency. The left side tended to be dominant. Copyright © 2015 Elsevier B.V. All rights reserved.
Jung Ah Lee; Sungkyu Lee; Hong-Jun Cho
2017-01-01
Introduction: The prevalence of adolescent electronic cigarette (e-cigarette) use has increased in most countries. This study aims to determine the relation between the frequency of e-cigarette use and the frequency and intensity of cigarette smoking. Additionally, the study evaluates the association between the reasons for e-cigarette use and the frequency of its use. Materials and Methods: Using the 2015 Korean Youth Risk Behavior Web-Based Survey, we included 6655 adolescents with an exper...
High intensity region segmentation in MR imaging of multiple sclerosis
International Nuclear Information System (INIS)
Rodrigo, F; Filipuzzi, M; Graffigna, J P; Isoardi, R; Noceti, M
2013-01-01
Numerous pathologies are often manifest in Magnetic Resonance Imaging (MRI) as hyperintense or bright regions as compared to normal tissue. It is of particular interest to develop an algorithm to detect, identify and define those Regions of Interest (ROI) when analyzing MRI studies, particularly for lesions of Multiple Sclerosis (MS). The objective of this study is to analyze those parameters which optimize segmentation of the areas of interest. To establish which areas should be considered as hyperintense regions, we developed a database (DB), with studies of patients diagnosed with MS. This disease causes axonal demyelination and it is expressed as bright regions in PD, T2 and FLAIR MRI sequences. Thus, with more than 4300 hyperintense regions validated by an expert physician, an algorithm was developed to detect such spots, approximating the results the expert obtained. Alongside these hyperintense lesion regions, it also detected bone regions with high intensity levels, similar to the intensity of the lesions, but with other features that allow a good differentiation.The algorithm will then detect ROIs with similar intensity levels and performs classification through data mining techniques
A simple Lissajous curves experimental setup
Şahin Kızılcık, Hasan; Damlı, Volkan
2018-05-01
The aim of this study is to develop an experimental setup to produce Lissajous curves. The setup was made using a smartphone, a powered speaker (computer speaker), a balloon, a laser pointer and a piece of mirror. Lissajous curves are formed as follows: a piece of mirror is attached to a balloon. The balloon is vibrated with the sound signal provided by the speaker that is connected to a smartphone. The laser beam is reflected off the mirror and the reflection is shaped as a Lissajous curve. Because of the intersection of two frequencies (frequency of the sound signal and natural vibration frequency of the balloon), these curves are formed. They can be used to measure the ratio of frequencies.
Directory of Open Access Journals (Sweden)
Hira H
2006-01-01
Full Text Available Background: Mechanical ventilation (MV is a life saving modality. Till no method is evolved to predict the duration of this treatment. This study is undertaken to evaluate the clinical and laboratory parameters at initiation and 48 hour of the patient being treated by mechanical ventilation; and correlate these parameters with the duration of MV required. Methods: It was prospective observational study conducted in the respiratory intensive care unit (RICU of a tertiary referral and teaching hospital. Thirty consecutive patients suffering from various medical diseases requiring MV were the participants. Clinical, laboratory, ventilatory parameters and six severity scores viz.; GCS, APACHE-II, SAPS, OSF, ALI/ARDS and Sepsis/Septic shock criteria of each patient, both at initiation and at 48 hour of MV were recorded. Correlation between various severity scores at initiation and at 48 hour of initiation with duration of mechanical ventilation was computed. Results: Based on the duration of mechanical ventilation required, the patients were divided in two groups. Those requiring mechanical ventilation < 7 days and> 7 days were designated Group I and Group II respectively. Three out of 6 severity scores (GCS, APACHE-II, SAPS recorded at 48 hour of MV showed statistically significant difference between the both groups with p value of 0.010, 0.009 and 0.006 respectively. Further stepwise logistic regression analysis showed that SAPS score at 48 hour of initiation was the best predictor of duration of MV. It was found that a cut off value of 15 for SAPS score at 48 hour might predict the duration of MV i.e. < 7days or> 7 days. Based on linear regression analysis a simple equation was formulated by putting the SAPS value at 48 hour, the value of Y was computed. If MV required was less than 7 days, the value of Y was more than - 0.172 and if need of mechanical ventilation was more than 7 days, Y was less than -0.1720. Conclusions: For patients requiring
Modelling financial high frequency data using point processes
DEFF Research Database (Denmark)
Hautsch, Nikolaus; Bauwens, Luc
In this chapter written for a forthcoming Handbook of Financial Time Series to be published by Springer-Verlag, we review the econometric literature on dynamic duration and intensity processes applied to high frequency financial data, which was boosted by the work of Engle and Russell (1997...
Lucid Dreaming: Intensity, But Not Frequency, Is Inversely Related to Psychopathology
Directory of Open Access Journals (Sweden)
Liat Aviram
2018-03-01
Full Text Available Lucid dreaming (LD is awareness that one is dreaming, during the dream state. However, some define and assess LD relying also on controlling dream events, although control is present only in a subset of lucid dreams. LD has been claimed to represent well-being, and has even been used as a therapeutic agent. Conversely, LD is associated with mixed sleep-wake states, which are related to bizarre cognitions, stress, and psychopathology, and have been construed as arousal permeating and disrupting sleep. We propose that previous conflicting findings regarding relations between LD and both psychopathology and well-being, stem from the non-differentiated assessment of frequency and control. The present study aimed to develop an expansive measure of several LD characteristics (the Frequency and Intensity Lucid Dream questionnaire; FILD, and explore their relations with symptomatology. Undergraduate students (N = 187 self-reported trait LD, psychopathology (depression, anxiety, obsessive-compulsive symptoms, dissociation, and schizotypy, stress, and sleep problems; 2 months later, a subsample (n = 78 reported psychopathology again, and also completed a dream diary each morning for 14 days. Preliminary evidence supports the reliability and validity of the FILD. Items converged into four domains: frequency, intensity (e.g., control, activity, certainty of dreaming, emotional valence, and the use of induction techniques. We report an optimal frequency cutoff score to identify those likely to experience LD within a 2-week period. Whereas LD frequency was unrelated to psychopathology, LD intensity, and positive LD emotions, were inversely associated with several psychopathological symptoms. Use of deliberate induction techniques was positively associated with psychopathology and sleep problems. Additionally, we demonstrated directionality by employing a prospective-longitudinal design, showing that deliberate LD induction predicted an increase in
Lucid Dreaming: Intensity, But Not Frequency, Is Inversely Related to Psychopathology
Aviram, Liat; Soffer-Dudek, Nirit
2018-01-01
Lucid dreaming (LD) is awareness that one is dreaming, during the dream state. However, some define and assess LD relying also on controlling dream events, although control is present only in a subset of lucid dreams. LD has been claimed to represent well-being, and has even been used as a therapeutic agent. Conversely, LD is associated with mixed sleep-wake states, which are related to bizarre cognitions, stress, and psychopathology, and have been construed as arousal permeating and disrupting sleep. We propose that previous conflicting findings regarding relations between LD and both psychopathology and well-being, stem from the non-differentiated assessment of frequency and control. The present study aimed to develop an expansive measure of several LD characteristics (the Frequency and Intensity Lucid Dream questionnaire; FILD), and explore their relations with symptomatology. Undergraduate students (N = 187) self-reported trait LD, psychopathology (depression, anxiety, obsessive-compulsive symptoms, dissociation, and schizotypy), stress, and sleep problems; 2 months later, a subsample (n = 78) reported psychopathology again, and also completed a dream diary each morning for 14 days. Preliminary evidence supports the reliability and validity of the FILD. Items converged into four domains: frequency, intensity (e.g., control, activity, certainty of dreaming), emotional valence, and the use of induction techniques. We report an optimal frequency cutoff score to identify those likely to experience LD within a 2-week period. Whereas LD frequency was unrelated to psychopathology, LD intensity, and positive LD emotions, were inversely associated with several psychopathological symptoms. Use of deliberate induction techniques was positively associated with psychopathology and sleep problems. Additionally, we demonstrated directionality by employing a prospective-longitudinal design, showing that deliberate LD induction predicted an increase in dissociation and
Regional variations in health care intensity and physician perceptions of quality of care.
Sirovich, Brenda E; Gottlieb, Daniel J; Welch, H Gilbert; Fisher, Elliott S
2006-05-02
Research has documented dramatic differences in health care utilization and spending across U.S. regions with similar levels of patient illness. Although patient outcomes and quality of care have been found to be no better in regions of high health care intensity, it is unknown whether physicians in these regions feel more capable of providing good patient care than those in low-intensity regions. To determine whether physicians in high-intensity regions feel better able to care for patients than physicians in low-intensity regions. Physician telephone survey. 51 metropolitan and 9 nonmetropolitan areas of the United States and a supplemental national sample. 10,577 physicians who provided care to adults in 1998 or 1999 were surveyed for the Community Tracking Study (response rate, 61%). The End-of-Life Expenditure Index, a measure of spending that reflects differences in the overall quantity of medical services provided rather than differences in illness or price, was used to determine health care intensity in the physicians' community. Outcomes included physicians' perceived availability of clinical services, ability to provide high-quality care to patients, and career satisfaction. Although the highest-intensity regions have substantially more hospital beds and specialists per capita, physicians in these regions reported more difficulty obtaining needed services for their patients. The proportion of physicians who felt able to obtain elective hospital admissions ranged from 50% in high-intensity regions to 64% in the lowest-intensity region (P market factors (for example, managed care penetration); the difference in perceived ability to provide high-quality care was no longer statistically significant (P = 0.099). The cross-sectional design prevented demonstration of a causal relationship between intensity and physician perceptions of quality. Despite more resources, physicians in regions of high health care intensity did not report greater ease in obtaining
Gaál, Ladislav; Kohnová, Silvia; Szolgay, Ján.
2010-05-01
During the last 10-15 years, the Slovak hydrologists and water resources managers have been devoting considerable efforts to develop statistical tools for modelling probabilities of flood occurrence in a regional context. Initially, these models followed concepts to regional flood frequency analysis that were based on fixed regions, later the Hosking and Wallis's (HW; 1997) theory was adopted and modified. Nevertheless, it turned out to be that delineating homogeneous regions using these approaches is not a straightforward task, mostly due to the complex orography of the country. In this poster we aim at revisiting flood frequency analyses so far accomplished for Slovakia by adopting one of the pooling approaches, i.e. the region-of-influence (ROI) approach (Burn, 1990). In the ROI approach, unique pooling groups of similar sites are defined for each site under study. The similarity of sites is defined through Euclidean distance in the space of site attributes that had also proved applicability in former cluster analyses: catchment area, afforested area, hydrogeological catchment index and the mean annual precipitation. The homogeneity of the proposed pooling groups is evaluated by the built-in homogeneity test by Lu and Stedinger (1992). Two alternatives of the ROI approach are examined: in the first one the target size of the pooling groups is adjusted to the target return period T of the estimated flood quantiles, while in the other one, the target size is fixed, regardless of the target T. The statistical models of the ROI approach are inter-compared by the conventional regionalization approach based on the HW methodology where the parameters of flood frequency distributions were derived by means of L-moment statistics and a regional formula for the estimation of the index flood was derived by multiple regression methods using physiographic and climatic catchment characteristics. The inter-comparison of different frequency models is evaluated by means of the
Raible, Daniel E.; Dinca, Dragos; Nayfeh, Taysir H.
2012-01-01
An effective form of wireless power transmission (WPT) has been developed to enable extended mission durations, increased coverage and added capabilities for both space and terrestrial applications that may benefit from optically delivered electrical energy. The high intensity laser power beaming (HILPB) system enables long range optical 'refueling" of electric platforms such as micro unmanned aerial vehicles (MUAV), airships, robotic exploration missions and spacecraft platforms. To further advance the HILPB technology, the focus of this investigation is to determine the optimal laser wavelength to be used with the HILPB receiver, which utilizes vertical multi-junction (VMJ) photovoltaic cells. Frequency optimization of the laser system is necessary in order to maximize the conversion efficiency at continuous high intensities, and thus increase the delivered power density of the HILPB system. Initial spectral characterizations of the device performed at the NASA Glenn Research Center (GRC) indicate the approximate range of peak optical-to-electrical conversion efficiencies, but these data sets represent transient conditions under lower levels of illumination. Extending these results to high levels of steady state illumination, with attention given to the compatibility of available commercial off-the-shelf semiconductor laser sources and atmospheric transmission constraints is the primary focus of this paper. Experimental hardware results utilizing high power continuous wave (CW) semiconductor lasers at four different operational frequencies near the indicated band gap of the photovoltaic VMJ cells are presented and discussed. In addition, the highest receiver power density achieved to date is demonstrated using a single photovoltaic VMJ cell, which provided an exceptionally high electrical output of 13.6 W/sq cm at an optical-to-electrical conversion efficiency of 24 percent. These results are very promising and scalable, as a potential 1.0 sq m HILPB receiver of
Smithers, Lisa G; Haag, Dandara G; Agnew, Benjamin; Lynch, John; Sorell, Matthew
2018-04-16
To estimate the frequency, duration and monthly pattern of discretionary food advertising on Australian free-to-air television. We logged 30 000 h of television collected in Adelaide during 2016 from one network that has four channels. The Australian Guide to Healthy Eating was used to identify discretionary foods. Data were examined according to all times, to children's peak viewing times (PVTs) and to when C-(children's) rated programmes may be broadcast. Of the >800 000 advertisements logged during 2016, 11% were for foods (n = 97 837). The most frequently advertised products were: snack foods (e.g. crisps), crumbed/battered meats, fast foods/take away meals and sweetened beverages. The frequency and duration of discretionary food advertising was 1.7 times/h and 0.5 min/h respectively at all times. During children's PVTs, the frequency and duration of discretionary food advertising was 2.3 times/h and 0.7 min/h, respectively. When C-rated programmes can be broadcast, the frequency and duration of discretionary food advertising was 1.8 times/h and 0.6 min/h, respectively. Across the year, discretionary foods ranged between 41% (August) and 71% (January) of all food advertising. Discretionary foods dominate food advertising. On average, discretionary food advertising was higher during PVTs for children and during the summer school holidays (January). © 2018 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).
Directory of Open Access Journals (Sweden)
Meghan Watson
Full Text Available Microstimulation of brain tissue plays a key role in a variety of sensory prosthetics, clinical therapies and research applications, however the effects of stimulation parameters on the responses they evoke remain widely unknown. In particular, the effects of parameters when delivered in the form of a stimulus train as opposed to a single pulse are not well understood despite the prevalence of stimulus train use. We aimed to investigate the contribution of each parameter of a stimulus train to the duration of the motor responses they evoke in forelimb muscles. We used constant-current, biphasic, square wave pulse trains in acute terminal experiments under ketamine anaesthesia. Stimulation parameters were systematically tested in a pair-wise fashion in the caudal forelimb region of the motor cortex in 7 Sprague-Dawley rats while motor evoked potential (MEP recordings from the forelimb were used to quantify the influence of each parameter in the train. Stimulus amplitude and train duration were shown to be the dominant parameters responsible for increasing the total duration of the MEP, while interphase interval had no effect. Increasing stimulus frequency from 100-200 Hz or pulse duration from 0.18-0.34 ms were also effective methods of extending response durations. Response duration was strongly correlated with peak time and amplitude. Our findings suggest that motor cortex intracortical microstimulations are often conducted at a higher frequency rate and longer train duration than necessary to evoke maximal response duration. We demonstrated that the temporal properties of the evoked response can be both predicted by certain response metrics and modulated via alterations to the stimulation signal parameters.
Southard, Rodney E.
2013-01-01
The weather and precipitation patterns in Missouri vary considerably from year to year. In 2008, the statewide average rainfall was 57.34 inches and in 2012, the statewide average rainfall was 30.64 inches. This variability in precipitation and resulting streamflow in Missouri underlies the necessity for water managers and users to have reliable streamflow statistics and a means to compute select statistics at ungaged locations for a better understanding of water availability. Knowledge of surface-water availability is dependent on the streamflow data that have been collected and analyzed by the U.S. Geological Survey for more than 100 years at approximately 350 streamgages throughout Missouri. The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, computed streamflow statistics at streamgages through the 2010 water year, defined periods of drought and defined methods to estimate streamflow statistics at ungaged locations, and developed regional regression equations to compute selected streamflow statistics at ungaged locations. Streamflow statistics and flow durations were computed for 532 streamgages in Missouri and in neighboring States of Missouri. For streamgages with more than 10 years of record, Kendall’s tau was computed to evaluate for trends in streamflow data. If trends were detected, the variable length method was used to define the period of no trend. Water years were removed from the dataset from the beginning of the record for a streamgage until no trend was detected. Low-flow frequency statistics were then computed for the entire period of record and for the period of no trend if 10 or more years of record were available for each analysis. Three methods are presented for computing selected streamflow statistics at ungaged locations. The first method uses power curve equations developed for 28 selected streams in Missouri and neighboring States that have multiple streamgages on the same streams. Statistical
Regional Variation in Gravel Riverbed Mobility, Controlled by Hydrologic Regime and Sediment Supply
Pfeiffer, Allison M.; Finnegan, Noah J.
2018-04-01
The frequency and intensity of riverbed mobility are of paramount importance to the inhabitants of river ecosystems as well as to the evolution of bed surface structure. Because sediment supply varies by orders of magnitude across North America, the intensity of bedload transport varies by over an order of magnitude. Climate also varies widely across the continent, yielding a range of flood timing, duration, and intermittency. Together, the differences in sediment supply and hydroclimate result in diverse regimes of bed surface stability. To quantitatively characterize this regional variation, we calculate multidecadal time series of estimated bed surface mobility for 29 rivers using sediment transport equations. We use these data to compare predicted bed mobility between rivers and regions. There are statistically significant regional differences in the (a) exceedance probability of bed-mobilizing flows (W* > 0.002), (b) maximum bed mobility, and (c) number of discrete bed-mobilizing events in a year.
X-ray absorption intensity at high-energy region
International Nuclear Information System (INIS)
Fujikawa, Takashi; Kaneko, Katsumi
2012-01-01
We theoretically discuss X-ray absorption intensity in high-energy region far from the deepest core threshold to explain the morphology-dependent mass attenuation coefficient of some carbon systems, carbon nanotubes (CNTs), highly oriented pyrolytic graphite (HOPG) and fullerenes (C 60 ). The present theoretical approach is based on the many-body X-ray absorption theory including the intrinsic losses (shake-up losses). In the high-energy region the absorption coefficient has correction term dependent on the solid state effects given in terms of the polarization part of the screened Coulomb interaction W p . We also discuss the tail of the valence band X-ray absorption intensity. In the carbon systems C 2s contribution has some influence on the attenuation coefficient even in the high energy region at 20 keV.
Energy Technology Data Exchange (ETDEWEB)
Lev, U; Prabhudesai, V; Natan, A; Bruner, B; Diner, A; Heber, O; Strasser, D; Schwalm, D; Silberberg, Y; Zajfman, D [Faculty of Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Ben-Itzhak, I; Hua, J J; Esry, B D, E-mail: uri.lev@Weizmann.ac.i [Department of Physics, Kansas State University, Manhattan, KS 66506 (United States)
2009-11-01
H{sub 2}{sup +} photodissociation, induced by intense short laser pulses, was measured by a full 3D imaging system. We have conducted a series of experiments, in which we systematically changed the linear chirp, using a pulse shaper, and observed the kinetic energy release spectra(KER). Distinct differences in the KER spectra are observed both in peak positions and angular distribution for laser pulses with similar duration and intensity but opposite chirp sign.
Assessing the hydrologic response to wildfires in mountainous regions
Havel, Aaron; Tasdighi, Ali; Arabi, Mazdak
2018-04-01
This study aims to understand the hydrologic responses to wildfires in mountainous regions at various spatial scales. The Soil and Water Assessment Tool (SWAT) was used to evaluate the hydrologic responses of the upper Cache la Poudre Watershed in Colorado to the 2012 High Park and Hewlett wildfire events. A baseline SWAT model was established to simulate the hydrology of the study area between the years 2000 and 2014. A procedure involving land use and curve number updating was implemented to assess the effects of wildfires. Application of the proposed procedure provides the ability to simulate the hydrologic response to wildfires seamlessly through mimicking the dynamic of the changes due to wildfires. The wildfire effects on curve numbers were determined comparing the probability distribution of curve numbers after calibrating the model for pre- and post-wildfire conditions. Daily calibration and testing of the model produced very good results. No-wildfire and wildfire scenarios were created and compared to quantify changes in average annual total runoff volume, water budgets, and full streamflow statistics at different spatial scales. At the watershed scale, wildfire conditions showed little impact on the hydrologic responses. However, a runoff increase up to 75 % was observed between the scenarios in sub-watersheds with high burn intensity. Generally, higher surface runoff and decreased subsurface flow were observed under post-wildfire conditions. Flow duration curves developed for burned sub-watersheds using full streamflow statistics showed that less frequent streamflows become greater in magnitude. A linear regression model was developed to assess the relationship between percent burned area and runoff increase in Cache la Poudre Watershed. A strong (R2 > 0.8) and significant (p statistics through application of flow duration curves revealed that the wildfires had a higher effect on peak flows, which may increase the risk of flash floods in post
Determination of regional cerebral blood flow curves and parameters by computed γ camera
International Nuclear Information System (INIS)
Zhu Guohong
1988-01-01
Regional CBF curves and parameters were determined in 236 subjects by Sigma 438/MCS 560 computed γ camera. Each subject was given 99m TcO 4 -370 MBq intravenously. Four CBF curves and three parameters were derived by the computer.The results from 39 normal subjects, 22 patients with cerebral embolism, 53 patients with cerebrovascular sclerosis, 56 patients with diseases of cervical vertebrae, 10 patients with concussion and 5 patients with cerebral arteritis were analyzed
Frequency conversion of high-intensity, femtosecond laser pulses
Energy Technology Data Exchange (ETDEWEB)
Banks, P S
1997-06-01
Almost since the invention of the laser, frequency conversion of optical pulses via non- linear processes has been an area of active interest. However, third harmonic generation using ~(~1 (THG) in solids is an area that has not received much attention because of ma- terial damage limits. Recently, the short, high-intensity pulses possible with chirped-pulse amplification (CPA) laser systems allow the use of intensities on the order of 1 TW/cm2 in thin solids without damage. As a light source to examine single-crystal THG in solids and other high field inter- actions, the design and construction of a Ti:sapphire-based CPA laser system capable of ultimately producing peak powers of 100 TW is presented. Of special interest is a novel, all-reflective pulse stretcher design which can stretch a pulse temporally by a factor of 20,000. The stretcher design can also compensate for the added material dispersion due to propagation through the amplifier chain and produce transform-limited 45 fs pulses upon compression. A series of laser-pumped amplifiers brings the peak power up to the terawatt level at 10 Hz, and the design calls for additional amplifiers to bring the power level to the 100 TW level for single shot operation. The theory for frequency conversion of these short pulses is presented, focusing on conversion to the third harmonic in single crystals of BBO, KD*P, and d-LAP (deuterated I-arginine phosphate). Conversion efficiencies of up to 6% are obtained with 500 fs pulses at 1053 nm in a 3 mm thick BBO crystal at 200 GW/cm 2. Contributions to this process by unphasematched, cascaded second harmonic generation and sum frequency generation are shown to be very significant. The angular relationship between the two orders is used to measure the tensor elements of C = xt3)/4 with Crs = -1.8 x 1O-23 m2/V2 and .15Cri + .54Crs = 4.0 x 1O-23 m2/V2. Conversion efficiency in d-LAP is about 20% that in BBO and conversion efficiency in KD*P is 1% that of BBO. It is calculated
Duration of surgical-orthodontic treatment.
Häll, Birgitta; Jämsä, Tapio; Soukka, Tero; Peltomäki, Timo
2008-10-01
To study the duration of surgical-orthodontic treatment with special reference to patients' age and the type of tooth movements, i.e. extraction vs. non-extraction and intrusion before or extrusion after surgery to level the curve of Spee. The material consisted files of 37 consecutive surgical-orthodontic patients. The files were reviewed and gender, diagnosis, type of malocclusion, age at the initiation of treatment, duration of treatment, type of tooth movements (extraction vs. non-extraction and levelling of the curve of Spee before or after operation) and type of operation were retrieved. For statistical analyses two sample t-test, Kruskal-Wallis and Spearman rank correlation tests were used. Mean treatment duration of the sample was 26.8 months, of which pre-surgical orthodontics took on average 17.5 months. Patients with extractions as part of the treatment had statistically and clinically significantly longer treatment duration, on average 8 months, than those without extractions. No other studied variable seemed to have an impact on the treatment time. The present small sample size prevents reliable conclusions to be made. However, the findings suggest, and patients should be informed, that extractions included in the treatment plan increase chances of longer duration of surgical-orthodontic treatment.
International Nuclear Information System (INIS)
Villanueva M, C.
2017-09-01
The concept of the annual load duration curve of the national interconnected system is presented, which by means of a quadrature procedure becomes a 3-block diagram: one for the base load that occurs at 8,760 hours of the year; another for intermediate load, above the minimum that occurs in a variable number of hours of the year, and another for the peak demand that only happens a few hours of the year. The data of the table of capacity and generation of electric power in 2014, according to Annex A of the Mexico Energy Outlook document of the International Energy Agency (Iea), are converted into a block diagram adjusted to the annual curve of load duration of that year. The procedure is repeated with the capacity and electric power generation data projected by the Iea at 2030 and 2040, according to the 450ppm scenario, which is considered necessary to stabilize the concentration of CO 2 in the atmosphere at 450 parts per million and ensure that the increase in the global temperature of the planet does not exceed 2 degrees Celsius, compared to pre-industrial levels. Then, the same capacity and generation data projected by the Iea by 2040 are tabulated by technology type, grouped now within the base, intermediate and peak blocks of the annual load duration curve for that year, and ordered from according to its plant factor, indicative of its availability to be dispatched. The above, in order to estimate the aggregate result of the annual dispatch that could be made by CENACE, if the projections of electric power generation to the year 2040 foreseen in the ambitious 450ppm scenario were given. Finally, an exercise is carried out to estimate, at 2015 prices, the unit costs of technologies generation in the year 2040, expressed in US D (2015)/ MWh and broken down into fixed and variable reference costs. (Author)
Niknajad, Akram; Ghojazadeh, Morteza; Sattarzadeh, Niloufar; Bashar Hashemi, Fazileh; Dezham Khoy Shahgholi, Farid
2012-01-01
Introduction: Improved survival of very low birth weight (VLBW) premature infants requires urgent intensive care, professional nursing and medical care. On the other hand, long hospital stay period imposes emotional and economic burdens on the family and society. Therefore, it is necessary to clarify the most important factors affecting their hospitalization duration to lessen unwanted outcomes of premature birth and to eliminate or relieve the problems. Methods: In a descri...
Deconstructing the Rosenfeld curve: Making sense of California's low electricity intensity
International Nuclear Information System (INIS)
Sudarshan, Anant
2013-01-01
Regulatory regimes that have increased household energy efficiency are of widespread interest to policymakers today. A prominent example is the state of California where electricity intensities in the residential sector have stayed near constant since the 1970s in sharp contrast to nationwide trends in the United States. A structural model of residential energy consumption is used to show that the use of energy intensities alone to evaluate the success of California efficiency programs is misleading and glosses over important policy independent factors. We quantify important effects of price, climate conditions and demographic characteristics on energy consumption in California. We also provide evidence of split incentive considerations in residential energy consumption patterns. We conclude that while state policy may have had some effect on efficiency, caution needs to be exercised in using the California example to inform expectations from similar measures in other regions. - Highlights: • We model electricity and heating fuel consumption in US households. • We use the structural model to estimate price elasticities. • California energy intensities are strongly influenced by policy independent factors. • The role of energy efficiency policy in lowering intensities is limited. • Evidence of split incentive considerations in energy demand
Linhart, S. Mike; Nania, Jon F.; Sanders, Curtis L.; Archfield, Stacey A.
2012-01-01
linear regression method and the daily mean streamflow for the 15th day of every other month. The Flow Duration Curve Transfer method was used to estimate unregulated daily mean streamflow from the physical and climatic characteristics of gaged basins. For the Flow Duration Curve Transfer method, daily mean streamflow quantiles at the ungaged site were estimated with the parameter-based regression model, which results in a continuous daily flow-duration curve (the relation between exceedance probability and streamflow for each day of observed streamflow) at the ungaged site. By the use of a reference streamgage, the Flow Duration Curve Transfer is converted to a time series. Data used in the Flow Duration Curve Transfer method were retrieved for 113 continuous-record streamgages in Iowa and within a 50-mile buffer of Iowa. The final statewide regression equations for Iowa were computed by using a weighted-least-squares multiple linear regression method and were computed for the 0.01-, 0.05-, 0.10-, 0.15-, 0.20-, 0.30-, 0.40-, 0.50-, 0.60-, 0.70-, 0.80-, 0.85-, 0.90-, and 0.95-exceedance probability statistics determined from the daily mean streamflow with a reporting limit set at 0.1 ft3/s. The final statewide regression equation for Iowa computed by using left-censored regression techniques was computed for the 0.99-exceedance probability statistic determined from the daily mean streamflow with a low limit threshold and a reporting limit set at 0.1 ft3/s. For the Flow Anywhere method, results of the validation study conducted by using six streamgages show that differences between the root-mean-square error and the mean absolute error ranged from 1,016 to 138 ft3/s, with the larger value signifying a greater occurrence of outliers between observed and estimated streamflows. Root-mean-square-error values ranged from 1,690 to 237 ft3/s. Values of the percent root-mean-square error ranged from 115 percent to 26.2 percent. The logarithm (base 10) streamflow percent root
Daoudi, Khalid; Hoogenboom, Martijn; den Brok, Martijn; Eikelenboom, Dylan; Adema, Gosse J; Fütterer, Jürgen J; de Korte, Chris L
2017-04-01
The thermal effect of high intensity focused ultrasound (HIFU) has been clinically exploited over a decade, while the mechanical HIFU is still largely confined to laboratory investigations. This is in part due to the lack of adequate imaging techniques to better understand the in-vivo pathological and immunological effects caused by the mechanical treatment. In this work, we explore the use of high frequency ultrasound (US) and photoacoustics (PA) as a potential tool to evaluate the effect of mechanical ablation in-vivo , e.g. boiling histotripsy. Two mice bearing a neuroblastoma tumor in the right leg were ablated using an MRI-HIFU system conceived for small animals and monitored using MRI thermometry. High frequency US and PA imaging were performed before and after the HIFU treatment. Afterwards, the tumor was resected for further assessment and evaluation of the ablated region using histopathology. High frequency US imaging revealed the presence of liquefied regions in the treated area together with fragmentized tissue which appeared with different reflecting proprieties compared to the surrounding tissue. Photoacoustic imaging on the other hand revealed the presence of deoxygenated blood within the tumor after the ablation due to the destruction of blood vessel network while color Doppler imaging confirmed the blood vessel network destruction within the tumor. The treated area and the presence of red blood cells detected by photoacoustics were further confirmed by the histopathology. This feasibility study demonstrates the potential of high frequency US and PA approach for assessing in-vivo the effect of mechanical HIFU tumor ablation.
Frequency dependent characteristics of solar impulsive radio bursts
International Nuclear Information System (INIS)
Das, T.K.; Das Gupta, M.K.
1983-01-01
An investigation was made of the impulsive radio bursts observed in the frequency range 0.245 to 35 GHz. Important results obtained are: (i) Simple type 1 bursts with intensities 0 to 10 f.u. and simple type 2 bursts with intensities 10 to 500 f.u. are predominant in the frequency ranges 1.415 to 4.995 GHz and 4.995 to 8.8 GHz, respectively; (ii) With maxima around 2.7 GHz and 4 GHz for the first and second types respectively, the durations of the radio bursts decrease gradually both towards lower and higher frequencies; (iii) As regards occurrences, the first type dominates in the southern solar hemisphere peaking around 8.8 GHz, whereas the second type favours the north with no well-defined maximum in any frequency; (iv) Both types prefer the eastern hemisphere, the peak occurrences being around 8.8 GHz and 5 GHz for the two successive types, respectively; (c) The spectra of impulsive radio bursts are generally of the inverted U-type with the maximum emission intensity between 5 and 15 GHz. (author)
Extreme Precipitation Estimation with Typhoon Morakot Using Frequency and Spatial Analysis
Directory of Open Access Journals (Sweden)
Hone-Jay Chu
2011-01-01
Full Text Available Typhoon Morakot lashed Taiwan and produced copious amounts of precipitation in 2009. From the point view of hydrological statistics, the impact of the precipitation from typhoon Morakot using a frequency analysis can be analyzed and discussed. The frequency curve, which was fitted mathematically to historical observed data, can be used to estimate the probability of exceedance for runoff events of a certain magnitude. The study integrates frequency analysis and spatial analysis to assess the effect of Typhoon Morakot event on rainfall frequency in the Gaoping River basin of southern Taiwan. First, extreme rainfall data are collected at sixteen stations for durations of 1, 3, 6, 12, and 24 hours and then an appropriate probability distribution was selected to analyze the impact of the extreme hydrological event. Spatial rainfall patterns for a return period of 200-yr with 24-hr duration with and without Typhoon Morakot are estimated. Results show that the rainfall amount is significantly different with long duration with and without the event for frequency analysis. Furthermore, spatial analysis shows that extreme rainfall for a return period of 200-yr is highly dependent on topography and is smaller in the southwest than that in the east. The results not only demonstrate the distinct effect of Typhoon Morakot on frequency analysis, but also could provide reference in future planning of hydrological engineering.
Research on frequency control strategy of interconnected region based on fuzzy PID
Zhang, Yan; Li, Chunlan
2018-05-01
In order to improve the frequency control performance of the interconnected power grid, overcome the problems of poor robustness and slow adjustment of traditional regulation, the paper puts forward a frequency control method based on fuzzy PID. The method takes the frequency deviation and tie-line deviation of each area as the control objective, takes the regional frequency deviation and its deviation as input, and uses fuzzy mathematics theory, adjusts PID control parameters online. By establishing the regional frequency control model of water-fire complementary power generation in MATLAB, the regional frequency control strategy is given, and three control modes (TBC-FTC, FTC-FTC, FFC-FTC) are simulated and analyzed. The simulation and experimental results show that, this method has better control performance compared with the traditional regional frequency regulation.
Energy Technology Data Exchange (ETDEWEB)
Chen, Li [Desert Research Inst. (DRI), Las Vegas, NV (United States). Division of Hydrologic Sciences; Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States). Division of Hydrologic Sciences
2016-08-01
Accurate precipitation frequency data are important for Environmental Management Soils Activities on the Nevada National Security Site (NNSS). These data are important for environmental assessments performed for regulatory closure of Soils Corrective Action Unit (CAU) Sites, as well as engineering mitigation designs and post-closure monitoring strategies to assess and minimize potential contaminant migration from Soils CAU Sites. Although the National Oceanic and Atmospheric Administration (NOAA) Atlas 14 (Bonnin et al., 2011) provides precipitation frequency data for the NNSS area, the NNSS-specific observed precipitation data were not consistent with the NOAA Atlas 14 predicted data. This is primarily due to the NOAA Atlas 14 products being produced from analyses without including the approximately 30 NNSS precipitation gage records, several of which approach or exceed 50 year of record. Therefore, a study of precipitation frequency that incorporated the NNSS precipitation gage records into the NOAA Atlas 14 dataset, was performed specifically for the NNSS to derive more accurate site-specific precipitation data products. Precipitation frequency information, such as the depth-duration-frequency (DDF) relationships, are required to generate synthetic standard design storm hydrographs and assess actual precipitation events. In this study, the actual long-term NNSS precipitation gage records, some of which are the longest gage records in southern and central Nevada, were analyzed to allow for more accurate precipitation DDF estimates to be developed for the NNSS. Gridded maps of precipitation frequency for the NNSS and surrounding areas were then produced.
Effect of low-frequency low-intensity ultrasound with microbubbles on prostate cancer hypoxia.
Hou, Rui; Xu, Yanjun; Lu, Qijie; Zhang, Yang; Hu, Bing
2017-10-01
Angiogenesis plays an important role in tumor growth, invasiveness, and metastasis. It is well established that prostate cancer is exposed to fluctuating oxygen tensions and both acute and chronic hypoxia exist, and these conditions can upregulate angiogenesis-associated proteins such as hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A. Low-frequency low-intensity ultrasound with microbubbles can induce obvious microvessel damage in tumors, cause cell necrosis or apoptosis. However, there is no information about whether the blocking blood effect of low-frequency low-intensity ultrasound with microbubbles has an influence on hypoxia environment of prostate cancer. Therefore, we investigated the impact of different low-frequency low-intensity ultrasound with microbubbles radiation times on prostate tumors, observed the change in the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A protein levels, as well as cell proliferation, apoptosis, and tumor volume. The results indicated that as the radiation was repeated four times on each treatment day, the effects of interruption were durable, the cell proliferation was inhibited, and apoptosis was promoted, and the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A expression levels were lower in the treatment group than in the control group. When the radiation was carried out once per treatment day, the hypoxia response was stimulated, the hypoxia-inducible factor 1 alpha and vascular endothelial growth factor A expression levels were higher compared with the control group, and cell proliferation was promoted. In addition, the tumor volume increased obviously in the hypoxia-stimulated group, whereas tumors grew slowly in the hypoxia-suppressed group. The results of this work demonstrated that under the same conditions, different radiation times of low-frequency low-intensity ultrasound with microbubbles affect the hypoxia response differently, and the
Climate Change Impact on Variability of Rainfall Intensity in Upper Blue Nile Basin, Ethiopia
Worku, L. Y.
2015-12-01
Extreme rainfall events are major problems in Ethiopia with the resulting floods that usually could cause significant damage to agriculture, ecology, infrastructure, disruption to human activities, loss of property, loss of lives and disease outbreak. The aim of this study was to explore the likely changes of precipitation extreme changes due to future climate change. The study specifically focuses to understand the future climate change impact on variability of rainfall intensity-duration-frequency in Upper Blue Nile basin. Precipitations data from two Global Climate Models (GCMs) have been used in the study are HadCM3 and CGCM3. Rainfall frequency analysis was carried out to estimate quantile with different return periods. Probability Weighted Method (PWM) selected estimation of parameter distribution and L-Moment Ratio Diagrams (LMRDs) used to find the best parent distribution for each station. Therefore, parent distributions for derived from frequency analysis are Generalized Logistic (GLOG), Generalized Extreme Value (GEV), and Gamma & Pearson III (P3) parent distribution. After analyzing estimated quantile simple disaggregation model was applied in order to find sub daily rainfall data. Finally the disaggregated rainfall is fitted to find IDF curve and the result shows in most parts of the basin rainfall intensity expected to increase in the future. As a result of the two GCM outputs, the study indicates there will be likely increase of precipitation extremes over the Blue Nile basin due to the changing climate. This study should be interpreted with caution as the GCM model outputs in this part of the world have huge uncertainty.
International Nuclear Information System (INIS)
Faktorov, Yi.Je.; Vyitte, P.M.; Jershova, M.O.; Belemets', M.P.; Chebanova, O.V.
1997-01-01
To study the frequency of illness with temporary loss of working ability (FITLWA) in the persons of main agricultural professions (drives, field workers, cattle breeders) working in the zone of strict radiation control (Polissia District, Kyiv Region) when compared with the 'clean' Lokhvytsia District, Poltava Region (the controls). FITLWA values were studied in 1496 workers. Within four year period after the accident at CAPP the residents of Polissia District received the dose of 2 rem due to Cesium-137, 134. Besides they were irradiated by incorporated Strontium-90, 89 and Plutonium-238,239,240. FITLWA values (duration of the illness, the number of patients) in all professional groups from this district have been established to be higher than in the controls. First of all it concerned the diseases of peripheral nervous system, gastrointestinal tract, respiratory organs, mental disorders, cardiovascular pathology
Lotspeich, R. Russell
2009-01-01
Natural-channel design involves constructing a stream channel with the dimensions, slope, and plan-view pattern that would be expected to transport water and sediment and yet maintain habitat and aesthetics consistent with unimpaired stream segments, or reaches. Regression relations for bankfull stream characteristics based on drainage area, referred to as 'regional curves,' are used in natural stream channel design to verify field determinations of bankfull discharge and stream channel characteristics. One-variable, ordinary least-squares regressions relating bankfull discharge, bankfull cross-sectional area, bankfull width, bankfull mean depth, and bankfull slope to drainage area were developed on the basis of data collected at 17 streamflow-gaging stations in rural areas with less than 20 percent urban land cover within the basin area (non-urban areas) of the Piedmont Physiographic Province in Virginia. These regional curves can be used to estimate the bankfull discharge and bankfull channel geometry when the drainage area of a watershed is known. Data collected included bankfull cross-sectional geometry, flood-plain geometry, and longitudinal profile data. In addition, particle-size distributions of streambed material were determined, and data on basin characteristics were compiled for each reach. Field data were analyzed to determine bankfull cross-sectional area, bankfull width, bankfull mean depth, bankfull discharge, bankfull channel slope, and D50 and D84 particle sizes at each site. The bankfull geometry from the 17 sites surveyed during this study represents the average of two riffle cross sections for each site. Regional curves developed for the 17 sites had coefficient of determination (R2) values of 0.950 for bankfull cross-sectional area, 0.913 for bankfull width, 0.915 for bankfull mean depth, 0.949 for bankfull discharge, and 0.497 for bankfull channel slope. The regional curves represent conditions for streams with defined channels and bankfull
Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation
Directory of Open Access Journals (Sweden)
Lei Yan
2016-01-01
Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.
DEFF Research Database (Denmark)
Kurth, Florian; Develoux, Michel; Mechain, Matthieu
2015-01-01
Intravenous artesunate improves survival in severe malaria, but clinical trial data from nonendemic countries are scarce. The TropNet severe malaria database was analyzed to compare outcomes of artesunate vs quinine treatment. Artesunate reduced parasite clearance time and duration of intensive...
Directory of Open Access Journals (Sweden)
D. P. Monselesan
2004-09-01
Full Text Available During summer months at solar cycle minimum, F-region lacuna and slant-Es conditions (SEC are common features of daytime ionograms recorded around local magnetic noon at Casey, Antarctica. Digisonde measurements of drift velocity height profiles show that the occurrence of lacuna prevents the determination of F-region drift velocities and also affects E-region drift velocity measurements. Unique E-region spectral features revealed as intervals of Bragg scatter superimposed on typical background E-region reflection were observed in Digisonde Doppler spectra during intense lacuna conditions. Daytime E-region Doppler spectra recorded at carrier frequencies from 1.5 to 2.7MHz, below the E-region critical frequency foE, have two side-peaks corresponding to Bragg scatter at approximately ±1-2Hz symmetrically located on each side of a central-peak corresponding to near-zenith total reflections. Angle-of-arrival information and ray-tracing simulations show that echo returns are coming from oblique directions most likely resulting from direct backscatter from just below the total reflection height for each sounding frequency. The Bragg backscatter events are shown to manifest during polar lacuna conditions, and to affect the determination of E-region background drift velocities, and as such must be considered when using standard Doppler-sorted interferometry (DSI techniques to estimate ionospheric drift velocities. Given the Doppler and spatial separation of the echoes determined from high-resolution Doppler measurements, we are able to estimate the Bragg scatter phase velocity independently from the bulk E-region motion. The phase velocity coincides with the ExB direction derived from in situ fluxgate magnetometer records. When ionospheric refraction is considered, the phase velocity amplitudes deduced from DSI are comparable to the ion-acoustic speed expected in the E-region. We briefly consider the plausibility that these
Directory of Open Access Journals (Sweden)
D. P. Monselesan
2004-09-01
Full Text Available During summer months at solar cycle minimum, F-region lacuna and slant-Es conditions (SEC are common features of daytime ionograms recorded around local magnetic noon at Casey, Antarctica. Digisonde measurements of drift velocity height profiles show that the occurrence of lacuna prevents the determination of F-region drift velocities and also affects E-region drift velocity measurements. Unique E-region spectral features revealed as intervals of Bragg scatter superimposed on typical background E-region reflection were observed in Digisonde Doppler spectra during intense lacuna conditions. Daytime E-region Doppler spectra recorded at carrier frequencies from 1.5 to 2.7MHz, below the E-region critical frequency foE, have two side-peaks corresponding to Bragg scatter at approximately ±1-2Hz symmetrically located on each side of a central-peak corresponding to near-zenith total reflections. Angle-of-arrival information and ray-tracing simulations show that echo returns are coming from oblique directions most likely resulting from direct backscatter from just below the total reflection height for each sounding frequency. The Bragg backscatter events are shown to manifest during polar lacuna conditions, and to affect the determination of E-region background drift velocities, and as such must be considered when using standard Doppler-sorted interferometry (DSI techniques to estimate ionospheric drift velocities. Given the Doppler and spatial separation of the echoes determined from high-resolution Doppler measurements, we are able to estimate the Bragg scatter phase velocity independently from the bulk E-region motion. The phase velocity coincides with the ExB direction derived from in situ fluxgate magnetometer records. When ionospheric refraction is considered, the phase velocity amplitudes deduced from DSI are comparable to the ion-acoustic speed expected in the E-region. We briefly consider the plausibility that these previously unreported polar
Gunther, Max L; Morandi, Alessandro; Krauskopf, Erin; Pandharipande, Pratik; Girard, Timothy D; Jackson, James C; Thompson, Jennifer; Shintani, Ayumi K; Geevarghese, Sunil; Miller, Russell R; Canonico, Angelo; Merkle, Kristen; Cannistraci, Christopher J; Rogers, Baxter P; Gatenby, J Chris; Heckers, Stephan; Gore, John C; Hopkins, Ramona O; Ely, E Wesley
2012-07-01
Delirium duration is predictive of long-term cognitive impairment in intensive care unit survivors. Hypothesizing that a neuroanatomical basis may exist for the relationship between delirium and long-term cognitive impairment, we conducted this exploratory investigation of the associations between delirium duration, brain volumes, and long-term cognitive impairment. A prospective cohort of medical and surgical intensive care unit survivors with respiratory failure or shock. Quantitative high resolution 3-Tesla brain magnetic resonance imaging was used to calculate brain volumes at discharge and 3-month follow-up. Delirium was evaluated using the confusion assessment method for the intensive care unit; cognitive outcomes were tested at 3- and 12-month follow-up. Linear regression was used to examine associations between delirium duration and brain volumes, and between brain volumes and cognitive outcomes. A total of 47 patients completed the magnetic resonance imaging protocol. Patients with longer duration of delirium displayed greater brain atrophy as measured by a larger ventricle-to-brain ratio at hospital discharge (0.76, 95% confidence intervals [0.10, 1.41]; p = .03) and at 3-month follow-up (0.62 [0.02, 1.21], p = .05). Longer duration of delirium was associated with smaller superior frontal lobe (-2.11 cm(3) [-3.89, -0.32]; p = .03) and hippocampal volumes at discharge (-0.58 cm(3) [-0.85, -0.31], p Battery for the Assessment of Neuropsychological Status score -11.17 [-21.12, -1.22], p = .04). Smaller superior frontal lobes, thalamus, and cerebellar volumes at 3 months were associated with worse executive functioning and visual attention at 12 months. These preliminary data show that longer duration of delirium is associated with smaller brain volumes up to 3 months after discharge, and that smaller brain volumes are associated with long-term cognitive impairment up to 12 months. We cannot, however, rule out that smaller preexisting brain volumes explain
Leypoldt, John K
2005-01-01
Current understanding of beta2-microglobulin (beta2M) and phosphate (or inorganic phosphorus) kinetics during hemodialysis is reviewed. The postdialysis:predialysis concentration ratio for beta2M is determined by dialyzer clearance for beta2M, treatment time, patient body size (specifically, extracellular fluid volume), and total ultrafiltration volume during the treatment. Evaluation of these treatment parameters can be used to calculate dialyzer clearance for beta2M; however, such calculated values are only approximations, since they neglect intradialytic generation, nonrenal (nondialyzer) clearance, and postdialysis rebound of beta2M. The detailed kinetics of beta2M during hemodialysis are best described using a two-compartment model. Theoretical predictions from such two-compartment models suggest that the product of dialyzer clearance for beta2M and weekly treatment duration, independent of treatment frequency, is the main determinant of plasma beta2M concentrations. The kinetics of phosphate removal during hemodialysis are incompletely understood. Phosphate is removed from both extracellular and intracellular compartments during hemodialysis; the plasma phosphate concentration levels off after the first 1 or 2 hours of treatment and plasma concentrations can rebound even before therapy is complete. Increases in dialyzer clearance of phosphate have been previously achieved only by increasing dialysis membrane surface area or by the use of hemodiafiltration. A four-compartment model of phosphate kinetics proposed recently by Spalding et al. suggests that the major barrier to phosphate removal is limited transfer of phosphate between the intracellular and extracellular compartments, although other complex factors also play important roles. Theoretical predictions using the model of Spalding et al. suggest that increasing either treatment frequency or treatment duration can increase phosphate removal. The kinetics of beta2M are representative of middle molecules
A simulation study of enhancement duration in three-dimensional contrast-enhanced MR angiography
International Nuclear Information System (INIS)
Ohkubo, Masaki; Ohgoshi, Yukio; Inoue, Tomoko; Naito, Kenichi; Suzuki, Kiyotaka
2001-01-01
In our study on three-dimensional (3D) contrast-enhanced MR angiography we performed a computer simulation to investigate quantitative vessel visibility. In the simulation, we evaluated the relative loss of signal intensity in a vessel due to shortened duration of contrast-enhancement. The mid-point of enhancement-duration was assumed to be at the point in which the data in the center of k-space (k y axis) was acquired. Signal intensity of a vessel decreased as the enhancement-duration was shortened and the diameter of the vessel was decreased. When the duration was shortened 40%, the signal intensity of a vessel in which the diameter was more than 2 pixels was preserved by approximately 70% or more. This suggests that the vessel visibility is high. When the duration was shortened 20%, the signal intensity of a vessel in which the diameter was less than 2 pixels decreased to less than approximately 40% or less. The simulation was confirmed by using 3D MR angiography with a tube phantom filled with Gd-DTPA to simulate a vessel model. At anytime during data acquisition, we could set the phantom on the region being scanned or take it out by using the ''pause'' function of the MR scanner. This made it possible to change the enhancement-duration to match the simulation. Results of the phantom study were comparable to those of the simulation, suggesting that the simulation was valid. Our results and simple techniques for both the simulation and the phantom study using the ''pause'' function, were considered useful in the study of 3D MR angiography. (author)
The role of low-frequency intraseasonal oscillations in the ...
Indian Academy of Sciences (India)
We analyze the dynamical features and responsible factors of the low-frequency intraseasonal time scales which influenced the nature of onset, intensity and duration of active/break phases and withdrawal of the monsoon during the anomalous Indian summer monsoon of 2002 – the most severe drought recorded in recent ...
Duration-frequency relationships of heavy rainfall in Santa Catarina, Brazil
Directory of Open Access Journals (Sweden)
Álvaro José Back
2012-06-01
Full Text Available The purpose of this study was to adjust equations that establish relationships between rainfall events with different duration and data from weather stations in the state of Santa Catarina, Brazil. In this study, the relationships between different duration heavy rainfalls from 13 weather stations of Santa Catarina were analyzed. From series of maximum annual rainfalls, and using the Gumbel-Chow distribution, the maximum rainfall for durations between 5 min and 24 h were estimated considering return periods from 2 to 100 years. The data fit to the Gumbel-Chow model was verified by the Kolmogorov-Smirnov test at 5 % significance. The coefficients of Bell's equation were adjusted to estimate the relationship between rainfall duration t (min and the return period T (y in relation to the maximum rainfall with a duration of 1 hour and a 10 year return period. Likewise, the coefficients of Bell's equation were adjusted based on the maximum rainfall with a duration of 1 day and a 10 year return period. The results showed that these relationships are viable to estimate short-duration rainfall events at locations where there are no rainfall records.
Probabilistic analysis of drought spatiotemporal characteristics inThessaly region, Greece
Directory of Open Access Journals (Sweden)
A. Loukas
2004-01-01
Full Text Available The temporal and spatial characteristics of meteorological drought are investigated to provide a framework for sustainable water resources management in the region of Thessaly, Greece. Thessaly is the most intensely cultivated and productive agricultural plain region in Greece. Thessaly's total area is about 13700 km2 and it is surrounded by mountains and traversed by Pinios River. Using the Standardized Precipitation Index (SPI as an indicator of drought severity, the characteristics of droughts are examined. Thessaly was divided into 212 grid-cells of 8 x 8 km and monthly precipitation data for the period 1960–1993 from 50 meteorological stations were used for global interpolation of precipitation using spatial co-ordinates and elevation data. Drought severity was assessed from the estimated gridded SPI values at multiple time scales. Firstly, the temporal and spatial characteristics of droughts were analyzed and then, Drought Severity – Areal extent – Frequency (SAF annual and monthly curves were developed. The analysis indicated that moderate and severe droughts are common in Thessaly region. Using the SAF curves, the return period of selected severe drought events was assessed.
Directory of Open Access Journals (Sweden)
Yongning Liu
2015-07-01
Full Text Available A time difference method to conveniently measure the phase shift between output wavelength and intensity of distributed feedback laser diodes (DFB-LDs was proposed. This approach takes advantage of asymmetric absorption positions at the same wavelength during wavelength increase and decrease tuning processes in the intensity-time curve by current modulation. For its practical implementation, a measurement example of phase shift was demonstrated by measuring a time difference between the first time and the second time attendances of the same gas absorption line in the intensity-time curve during one sine or triangle modulation circle. The phase shifts at modulation frequencies ranging from 50 Hz to 50 kHz were measured with a resolution of 0.001π. As the modulation frequency increased the shift value increased with a slowed growth rate.
Frequency and determinants of drug administration errors in the intensive care unit
van den Bemt, PMLA; Fijn, R; van der Voort, PHJ; Gossen, AA; Egberts, TCG; Brouwers, JRBJ
Objective., The study aimed to identify both the frequency and the determinants of drug administration errors in the intensive care unit. Design: Administration errors were detected by using the disguised-observation technique (observation of medication administrations by nurses, without revealing
Analysis of magnitude and duration of floods and droughts in the context of climate change
Eshetu Debele, Sisay; Bogdanowicz, Ewa; Strupczewski, Witold
2016-04-01
Research and scientific information are key elements of any decision-making process. There is also a strong need for tools to describe and compare in a concise way the regime of hydrological extreme events in the context of presumed climate change. To meet these demands, two complementary methods for estimating high and low-flow frequency characteristics are proposed. Both methods deal with duration and magnitude of extreme events. The first one "flow-duration-frequency" (known as QdF) has already been applied successfully to low-flow analysis, flood flows and rainfall intensity. The second one called "duration-flow-frequency" (DqF) was proposed by Strupczewski et al. in 2010 to flood frequency analysis. The two methods differ in the treatment of flow and duration. In the QdF method the duration (d-consecutive days) is a chosen fixed value and the frequency analysis concerns the annual or seasonal series of mean value of flows exceeded (in the case of floods) or non-exceeded (in the case of droughts) within d-day period. In the second method, DqF, the flows are treated as fixed thresholds and the duration of flows exceeding (floods) and non-exceeding (droughts) these thresholds are a subject of frequency analysis. The comparison of characteristics of floods and droughts in reference period and under future climate conditions for catchments studied within the CHIHE project is presented and a simple way to show the results to non-professionals and decision-makers is proposed. The work was undertaken within the project "Climate Change Impacts on Hydrological Extremes (CHIHE)", which is supported by the Norway-Poland Grants Program administered by the Norwegian Research Council. The observed time series were provided by the Institute of Meteorology and Water Management (IMGW), Poland. Strupczewski, W. G., Kochanek, K., Markiewicz, I., Bogdanowicz, E., Weglarczyk, S., & Singh V. P. (2010). On the Tails of Distributions of Annual Peak Flow. Hydrology Research, 42, 171
Energy Technology Data Exchange (ETDEWEB)
Gunawan, H.; Puspito, N. T.; Ibrahim, G.; Harjadi, P. J. P. [ITB, Faculty of Earth Sciences and Tecnology (Indonesia); BMKG (Indonesia)
2012-06-20
The new approach method to determine the magnitude by using amplitude displacement relationship (A), epicenter distance ({Delta}) and duration of high frequency radiation (t) has been investigated for Tasikmalaya earthquake, on September 2, 2009, and their aftershock. Moment magnitude scale commonly used seismic surface waves with the teleseismic range of the period is greater than 200 seconds or a moment magnitude of the P wave using teleseismic seismogram data and the range of 10-60 seconds. In this research techniques have been developed a new approach to determine the displacement amplitude and duration of high frequency radiation using near earthquake. Determination of the duration of high frequency using half of period of P waves on the seismograms displacement. This is due tothe very complex rupture process in the near earthquake. Seismic data of the P wave mixing with other wave (S wave) before the duration runs out, so it is difficult to separate or determined the final of P-wave. Application of the 68 earthquakes recorded by station of CISI, Garut West Java, the following relationship is obtained: Mw = 0.78 log (A) + 0.83 log {Delta}+ 0.69 log (t) + 6.46 with: A (m), d (km) and t (second). Moment magnitude of this new approach is quite reliable, time processing faster so useful for early warning.
Gunawan, H.; Puspito, N. T.; Ibrahim, G.; Harjadi, P. J. P.
2012-06-01
The new approach method to determine the magnitude by using amplitude displacement relationship (A), epicenter distance (Δ) and duration of high frequency radiation (t) has been investigated for Tasikmalaya earthquake, on September 2, 2009, and their aftershock. Moment magnitude scale commonly used seismic surface waves with the teleseismic range of the period is greater than 200 seconds or a moment magnitude of the P wave using teleseismic seismogram data and the range of 10-60 seconds. In this research techniques have been developed a new approach to determine the displacement amplitude and duration of high frequency radiation using near earthquake. Determination of the duration of high frequency using half of period of P waves on the seismograms displacement. This is due tothe very complex rupture process in the near earthquake. Seismic data of the P wave mixing with other wave (S wave) before the duration runs out, so it is difficult to separate or determined the final of P-wave. Application of the 68 earthquakes recorded by station of CISI, Garut West Java, the following relationship is obtained: Mw = 0.78 log (A) + 0.83 log Δ + 0.69 log (t) + 6.46 with: A (m), d (km) and t (second). Moment magnitude of this new approach is quite reliable, time processing faster so useful for early warning.
International Nuclear Information System (INIS)
Gunawan, H.; Puspito, N. T.; Ibrahim, G.; Harjadi, P. J. P.
2012-01-01
The new approach method to determine the magnitude by using amplitude displacement relationship (A), epicenter distance (Δ) and duration of high frequency radiation (t) has been investigated for Tasikmalaya earthquake, on September 2, 2009, and their aftershock. Moment magnitude scale commonly used seismic surface waves with the teleseismic range of the period is greater than 200 seconds or a moment magnitude of the P wave using teleseismic seismogram data and the range of 10-60 seconds. In this research techniques have been developed a new approach to determine the displacement amplitude and duration of high frequency radiation using near earthquake. Determination of the duration of high frequency using half of period of P waves on the seismograms displacement. This is due tothe very complex rupture process in the near earthquake. Seismic data of the P wave mixing with other wave (S wave) before the duration runs out, so it is difficult to separate or determined the final of P-wave. Application of the 68 earthquakes recorded by station of CISI, Garut West Java, the following relationship is obtained: Mw = 0.78 log (A) + 0.83 log Δ+ 0.69 log (t) + 6.46 with: A (m), d (km) and t (second). Moment magnitude of this new approach is quite reliable, time processing faster so useful for early warning.
International Nuclear Information System (INIS)
Mendonca, Julyanne C.G.; Mendes, Mariana E.; Hwang, Suy F.; Lima, Fabiana F.; Santos, Neide
2014-01-01
The cytogenetic study has the chromosomal alterations as biomarkers in absorbed dose estimation by the body of individuals involved in exposure to ionizing radiation by interpreting a dose response calibration curve. Since the development of the technique to the analysis of data, you can see protocol characteristics, leading the International Atomic Energy Agency indicate that any laboratory with intention to carry out biological dosimetry establish their own calibration curves. The Biological Dosimetry Laboratory of the Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN), Brazil, recently established the calibration curve related to gamma radiation ( 60 Co). Thus, this work aimed to start the validation of this calibration curve from samples of three different blood donors which were irradiated with an absorbed known single dose of 1 Gy. Samples were exposed to 60 Co source (Glaucoma 220) located in the Department of Nuclear Energy (DEN/UFPE). After fixation with methanol and acetic acid and 5% Giemsa staining, the frequency of chromosomal alterations (dicentric chromosomes, acentric rings and fragments) were established from reading of 500 metaphases per sample and doses were estimated using Dose Estimate program. The results showed that, using the dose-response curve calibration for dicentrics, the dose absorbed estimated for the three individuals ranged from 0.891 - 1,089Gy, taking into account the range of confidence of 95%. By using the dose-response curve for dicentrics added to rings and for the same interval of confidence the doses ranged from 0,849 - 1,081Gy. Thus, the estimative encompassed known absorbed dose the three individuals in confidence interval of 95%. These preliminary results seems to demonstrate that dicentric dose-response curves and dicentrics plus rings established by CRCN-NE / CNEN are valid for dose estimation in exposed individuals. This validation will continue with samples from different individuals at different doses
Methods for predicting isochronous stress-strain curves
International Nuclear Information System (INIS)
Kiyoshige, Masanori; Shimizu, Shigeki; Satoh, Keisuke.
1976-01-01
Isochronous stress-strain curves show the relation between stress and total strain at a certain temperature with time as a parameter, and they are drawn up from the creep test results at various stress levels at a definite temperature. The concept regarding the isochronous stress-strain curves was proposed by McVetty in 1930s, and has been used for the design of aero-engines. Recently the high temperature characteristics of materials are shown as the isochronous stress-strain curves in the design guide for the nuclear energy equipments and structures used in high temperature creep region. It is prescribed that these curves are used as the criteria for determining design stress intensity or the data for analyzing the superposed effects of creep and fatigue. In case of the isochronous stress-strain curves used for the design of nuclear energy equipments with very long service life, it is impractical to determine the curves directly from the results of long time creep test, accordingly the method of predicting long time stress-strain curves from short time creep test results must be established. The method proposed by the authors, for which the creep constitution equations taking the first and second creep stages into account are used, and the method using Larson-Miller parameter were studied, and it was found that both methods were reliable for the prediction. (Kako, I.)
Mapping of lichen frequencies as a tool in evaluating intensity of pollution
Energy Technology Data Exchange (ETDEWEB)
Kunze, M
1972-01-01
A method is presented for determining the intensity of air pollution by evaluating the frequency of lichen species growing on the trunks of trees. The lichens growing on the trunks of isolated trees in the surroundings of factories or other pollutants have been investigated. A ladder enclosing the panels is used to determine the frequency: the calculation is made electronically and permits statistical statements about the quantity of the lichens to be made. The numerical material evaluated consists of reproduceable data obtained by a standardized method that appears to be suitable for routine use. Pollution zones can be recognized by changes in frequency of the various sensitive species.
A possible constraint on regional precipitation intensity changes under global warming
DEFF Research Database (Denmark)
Gutowski, William J.; Kozak, K. A.; Arritt, R. W.
2007-01-01
Changes in daily precipitation versus intensity under a global warming scenario in two regional climate simulations of the United States show a well-recognized feature of more intense precipitation. More important, by resolving the precipitation intensity spectrum, the changes show a relatively...
Properties of Extreme Point Rainfall I
DEFF Research Database (Denmark)
Harremoës, Poul; Mikkelsen, Peter Steen
1995-01-01
Extreme rainfall has been recorded by the larger municipalities in Denmark since 1933. National intensity-duration-frequency curves were produced on this basis for engineering application in the whole of Denmark. In 1979, on the initiative of The Danish Water Pollution Control Committee under...
International Nuclear Information System (INIS)
Poveda, German; Mesa, Oscar; Toro, Vladimir; Agudelo, Paula; Alvarez, Juan F; Arias, Paola; Moreno, Hernan; Salazar, Luis; Vieira, Sara
2002-01-01
We study the distribution of maximum rainfall events during the annual cycle, for storms ranging from 1 to 24-hour in duration; by using information over 51 rain gauges locate at the Colombian Andes. Also, the effects of both phases of ENSO (El Nino and La Nina) are quantified. We found that maximum rainfall intensity events occur during the rainy periods of march-may and September-November. There is a strong similarity between the annual cycle of mean total rainfall and that of the maximum intensities of rainfall over the tropical Andes. This result is quite consistent throughout the three ranges of the Colombian Andes. At inter annual timescales, we found that both phases of ENSO are associated with disturbances of maximum rainfall events; since during La Nina there are more intense precipitation events than during El Nino, overall, for durations longer than 3 hours, rainfall intensity gets reduced by one order of magnitude with respect to shorter durations (1-3 hours). The most extreme recorded rainfall events are apparently not associated with the annual and inter annual large scales forcing and appear to be randomly generated by the important role of the land surface atmosphere in the genesis and dynamics of intense storm over central Colombia
Huang, Hui; Zhu, Zheng-Qiu; Zhou, Zheng-Guo; Chen, Ling-Shan; Zhao, Ming; Zhang, Yang; Li, Hong-Bo; Yin, Li-Ping
2016-12-08
To assess the role of time-intensity curves (TICs) of the normal peripheral zone (PZ) in the identification of biopsy-proven prostate nodules using contrast-enhanced transrectal ultrasound (CETRUS). This study included 132 patients with 134 prostate PZ nodules. Arrival time (AT), peak intensity (PI), mean transit time (MTT), area under the curve (AUC), time from peak to one half (TPH), wash in slope (WIS) and time to peak (TTP) were analyzed using multivariate linear logistic regression and receiver operating characteristic (ROC) curves to assess whether combining nodule TICs with normal PZ TICs improved the prediction of prostate cancer (PCa) aggressiveness. The PI, AUC (p < 0.001 for both), MTT and TPH (p = 0.011 and 0.040 respectively) values of the malignant nodules were significantly higher than those of the benign nodules. Incorporating the PI and AUC values (both, p < 0.001) of the normal PZ TIC, but not the MTT and TPH values (p = 0.076 and 0.159 respectively), significantly improved the AUC for prediction of malignancy (PI: 0.784-0.923; AUC: 0.758-0.891) and assessment of cancer aggressiveness (p < 0.001). Thus, all these findings indicate that incorporating normal PZ TICs with nodule TICs in CETRUS readings can improve the diagnostic accuracy for PCa and cancer aggressiveness assessment.
Pattern of side feeding intensity in mass 40 region
International Nuclear Information System (INIS)
Kshetri, Ritesh; Ray, Indrani; Mukherjee, A.
2005-01-01
Mass 40 region has many interesting features to offer to the fields of nuclear structure. In this paper, intention was made to study the effect of forward and inverse type of reaction and excitation energy on the side feeding intensity pattern in the mass region 40. The effect of coexistence of different types of structural features in this mass region will also be investigated
Intensity attenuation for active crustal regions
Allen, Trevor I.; Wald, David J.; Worden, C. Bruce
2012-07-01
We develop globally applicable macroseismic intensity prediction equations (IPEs) for earthquakes of moment magnitude M W 5.0-7.9 and intensities of degree II and greater for distances less than 300 km for active crustal regions. The IPEs are developed for two distance metrics: closest distance to rupture ( R rup) and hypocentral distance ( R hyp). The key objective for developing the model based on hypocentral distance—in addition to more rigorous and standard measure R rup—is to provide an IPE which can be used in near real-time earthquake response systems for earthquakes anywhere in the world, where information regarding the rupture dimensions of a fault may not be known in the immediate aftermath of the event. We observe that our models, particularly the model for the R rup distance metric, generally have low median residuals with magnitude and distance. In particular, we address whether the direct use of IPEs leads to a reduction in overall uncertainties when compared with methods which use a combination of ground-motion prediction equations and ground motion to intensity conversion equations. Finally, using topographic gradient as a proxy and median model predictions, we derive intensity-based site amplification factors. These factors lead to a small reduction of residuals at shallow gradients at strong shaking levels. However, the overall effect on total median residuals is relatively small. This is in part due to the observation that the median site condition for intensity observations used to develop these IPEs is approximately near the National Earthquake Hazard Reduction Program CD site-class boundary.
Distal clavicular osteolysis in adults: association with bench pressing intensity
Energy Technology Data Exchange (ETDEWEB)
Nevalainen, Mika T.; Morrison, William B.; Zoga, Adam C.; Roedl, Johannes B. [Sidney Kimmel Medical College at Thomas Jefferson University, Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA (United States); Ciccotti, Michael G. [Sidney Kimmel Medical College at Thomas Jefferson University, Division of Sports Medicine, Department of Orthopedic Surgery, Thomas Jefferson University Hospital, Rothman Institute, Philadelphia, PA (United States)
2016-11-15
To investigate the association between distal clavicular osteolysis (DCO) and bench pressing intensity. From a retrospective review of MRI shoulder reports of individuals between 20 and 40 years of age, 262 male patients with DCO and 227 age-matched male patients without DCO were selected. All patients had completed a bench pressing questionnaire. The patients' bench pressing frequency (times per week), duration (years of bench pressing), bench pressing weight (maximum bench pressing weight with one repetition = 1RM) and the ratio of bench pressing weight to body weight were compared between both groups using Chi-square and Mann-Whitney tests. The results showed that 56 % (146/262) of patients with DCO were high-intensity bench pressers (1RM more than 1.5 times the body weight) compared to 6 % (14/227) in patients without DCO. High-intensity bench pressing was a risk factor for DCO (OR = 19; 95 %CI = 11-35; p < 0.001). Low-intensity bench pressing (1RM less than 1.5 times the body weight) was not a risk factor for DCO (OR = 0.6; 95 % CI = 0.4-0.8). High frequency (>1 x /week) and duration (>5 years) of bench pressing were risk factors. In bench pressers who suffered from DCO, the mean 1RM was 283 lbs (±SD 57) compared to 209 lbs (±SD 60) in bench pressers not affected by DCO (p < 0.001, Mann-Whitney). High-intensity, but not low-intensity bench pressing is a risk factor for DCO. (orig.)
Contributions to the R-curve behaviour of ceramic materials
International Nuclear Information System (INIS)
Fett, T.
1994-12-01
Several ceramic materials show an increase in crack growth resistance with increasing crack extension. Especially, in case of coarse-grained alumina this ''R-curve effect'' is caused by crack-face interactions in the wake of the advancing crack. Similar effects occur for whisker reinforced ceramics. Due to the crack-face interactions so-called ''bridging stresses'' are generated which transfer forces between the two crack surfaces. A second reason for an increase of crack-growth resistance are stress-induced phase transformations in zirconia ceramics with the tetragonal phase changing to the monoclinic phase. These transformations will affect the stress field in the surroundings of crack tips. The transformation generates a crack-tip transformation zone and, due to the stress balance, also residual stresses in the whole crack region which result in a residual stress intensity factor. This additional stress intensity factor is also a reason for the R-curve behaviour. In this report both effects are outlined in detail. (orig.) [de
Energy consumption and energetic intensities in the Mato Grosso meso-region 01
International Nuclear Information System (INIS)
Canavarros, Otacilio Borges; Silva, Ennio Peres da
1999-01-01
The energy intensity of a regional economy is dependent on its structure and degree of industrialization. Considering comparable general conditions it is also a measure for the efficient use of energy. Energy consumption contribute decisively to the modification of economical structures and to the decrease in energy intensity. In this context, the aim of the work was to evaluate the energy consumption and the energy intensity in a region of Mato Grosso State, Brazil
Hao, X; Bruce, C J; Pislaru, C; Greenleaf, J F
2001-12-01
Segmenting abnormal from normal myocardium using high-frequency intracardiac echocardiography (ICE) images presents new challenges for image processing. Gray-level intensity and texture features of ICE images of myocardium with the same structural/perfusion properties differ. This significant limitation conflicts with the fundamental assumption on which existing segmentation techniques are based. This paper describes a new seeded region growing method to overcome the limitations of the existing segmentation techniques. Three criteria are used for region growing control: 1) Each pixel is merged into the globally closest region in the multifeature space. 2) "Geographic similarity" is introduced to overcome the problem that myocardial tissue, despite having the same property (i.e., perfusion status), may be segmented into several different regions using existing segmentation methods. 3) "Equal opportunity competence" criterion is employed making results independent of processing order. This novel segmentation method is applied to in vivo intracardiac ultrasound images using pathology as the reference method for the ground truth. The corresponding results demonstrate that this method is reliable and effective.
Granados, I.; Calo, M.; Ramos, V.
2017-12-01
We developed a Matlab suite package (NDCP, Noisy Dispersion Curve Picking) that allows a full control over parameters to identify correctly group velocity dispersion curves in two types of datasets: correlograms between two stations or surface wave records from earthquakes. Using the frequency-time analysis (FTAN), the procedure to obtain the dispersion curves from records with a high noise level becomes difficult, and sometimes, the picked curve result in a misinterpreted character. For correlogram functions, obtained with cross-correlation of noise records or earthquake's coda, a non-homogeneous noise sources distribution yield to a non-symmetric Green's function (GF); to retrieve the complete information contained in there, NDCP allows to pick the dispersion curve in the time domain both in the causal and non-causal part of the GF. Then the picked dispersion curve is displayed on the FTAN diagram to in order to check if it matches with the maximum of the signal energy avoiding confusion with overtones or spike of noise. To illustrate how NDCP performs, we show exemple using: i) local correlograms functions obtained from sensors deployed into a volcanic caldera (Los Humeros, in Puebla, Mexico), ii) regional correlograms functions between two stations of the National Seismological Service (SSN, Servicio Sismológico Nacional in Spanish), and iii) surface wave seismic record for an earthquake located in the Pacific Ocean coast of Mexico and recorded by the SSN. This work is supported by the GEMEX project (Geothermal Europe-Mexico consortium).
The environmental Kuznets curve hypothesis for water pollution. Do regions matter?
Energy Technology Data Exchange (ETDEWEB)
Lee, Chien-Chiang; Chiu, Yi-Bin [Department of Finance, National Sun Yat-Sen University Kaohsiung (China); Sun, Chia-Hung [Department of Economics, National Chung Cheng University (China)
2010-01-15
This study revisits the environmental Kuznets curve (EKC) hypothesis for water pollution by using a recent dynamic technique, which is the generalized method of moments (GMM) approach, for a board sample of 97 countries during the period 1980-2001. On a global scale, as we cannot obtain the EKC relationship between real income and biological oxygen demand (BOD) emissions, this paper further classifies these countries into four regional groups - Africa, Asia and Oceania, America, and Europe - to explore whether the different regions have different ECK relationships. The empirical results show evidence of the inverted U-shaped EKC relationships' existence in America and Europe, but not in Africa and Asia and Oceania. Thus, the regional difference of EKC for water pollution is supported. Furthermore, the estimated turning points are, approximately, US$13,956 and US$38,221 for America and Europe, respectively. (author)
The environmental Kuznets curve hypothesis for water pollution: Do regions matter?
Energy Technology Data Exchange (ETDEWEB)
Lee, C.-C., E-mail: leecc@seed.net.t [Department of Finance, National Sun Yat-Sen University Kaohsiung, Taiwan (China); Chiu, Y.-B. [Department of Finance, National Sun Yat-Sen University Kaohsiung, Taiwan (China); Sun, C.-H. [Department of Economics, National Chung Cheng University, Taiwan (China)
2010-01-15
This study revisits the environmental Kuznets curve (EKC) hypothesis for water pollution by using a recent dynamic technique, which is the generalized method of moments (GMM) approach, for a board sample of 97 countries during the period 1980-2001. On a global scale, as we cannot obtain the EKC relationship between real income and biological oxygen demand (BOD) emissions, this paper further classifies these countries into four regional groups - Africa, Asia and Oceania, America, and Europe - to explore whether the different regions have different ECK relationships. The empirical results show evidence of the inverted U-shaped EKC relationships' existence in America and Europe, but not in Africa and Asia and Oceania. Thus, the regional difference of EKC for water pollution is supported. Furthermore, the estimated turning points are, approximately, US$13,956 and US$38,221 for America and Europe, respectively.
The environmental Kuznets curve hypothesis for water pollution: Do regions matter?
International Nuclear Information System (INIS)
Lee, C.-C.; Chiu, Y.-B.; Sun, C.-H.
2010-01-01
This study revisits the environmental Kuznets curve (EKC) hypothesis for water pollution by using a recent dynamic technique, which is the generalized method of moments (GMM) approach, for a board sample of 97 countries during the period 1980-2001. On a global scale, as we cannot obtain the EKC relationship between real income and biological oxygen demand (BOD) emissions, this paper further classifies these countries into four regional groups - Africa, Asia and Oceania, America, and Europe - to explore whether the different regions have different ECK relationships. The empirical results show evidence of the inverted U-shaped EKC relationships' existence in America and Europe, but not in Africa and Asia and Oceania. Thus, the regional difference of EKC for water pollution is supported. Furthermore, the estimated turning points are, approximately, US$13,956 and US$38,221 for America and Europe, respectively.
Moos, Rudolf H.; Moos, Bernice S.
2004-01-01
This study examined the influence of the duration and frequency of a baseline episode of participation in Alcoholics Anonymous (AA) among 473 individuals with alcohol use disorders on 1-year and 8-year outcomes and the effect of additional participation and delayed participation on outcomes. Compared with individuals who did not participate,…
Mulavara, Ajitkumar; Wood, Scott; Fiedler, Matthew; Kofman, Igor; Kulecz, Walter B.; Miller, Chris; Peters, Brian; Serrador, Jorge; Cohen, Helen; Reschke, Millard;
2010-01-01
Astronauts experience sensorimotor disturbances after long-duration space flight. After a water landing, crewmembers may need to egress the vehicle within a few minutes for safety and operational reasons in various sea state conditions. Exposure to even low-frequency motions induced by sea conditions surrounding a vessel can cause significant motor control problems affecting critical functions. The first objective of this study was to document human visual performance during simulated wave motion below 2.0 Hz. We examined the changes in accuracy and reaction time when subjects performed a visual target acquisition task in which the location of the target was offset vertically during horizontal rotation at an oscillating frequency of 0.8 Hz. The main finding was that both accuracy and reaction time varied as a function of target location, with greater performance decrements occurring when vertical targets were acquired at perturbing frequencies of 0.8 Hz in the horizontal plane. A second objective was to develop a countermeasure, base d on stochastic resonance (SR), to enhance sensorimotor capabilities with the aim of facilitating rapid adaptation to gravitational transitions after long-duration space flight. SR is a mechanism by which noise can enhance the response of neural systems to relevant sensory signals. Recent studies have shown that applying imperceptible stochastic electrical stimulation to the vestibular system (SVS) significantly improved balance and oculomotor responses. This study examined the effectiveness of SVS on improving balance performance. Subjects performed a standard balance task while bipolar SVS was applied to the vestibular system using constant current stimulation through electrodes placed over the mastoid process. The main finding of this study was that balance performance with the application of SR showed significant improvement in the range of 10%-25%. Ultimately an SR-based countermeasure might be fielded either as preflight training
Implementation of the Master Curve method in ProSACC
Energy Technology Data Exchange (ETDEWEB)
Feilitzen, Carl von; Sattari-Far, Iradj [Inspecta Technology AB, Stockholm (Sweden)
2012-03-15
Cleavage fracture toughness data display normally large amount of statistical scatter in the transition region. The cleavage toughness data in this region is specimen size-dependent, and should be treated statistically rather than deterministically. Master Curve methodology is a procedure for mechanical testing and statistical analysis of fracture toughness of ferritic steels in the transition region. The methodology accounts for temperature and size dependence of fracture toughness. Using the Master Curve methodology for evaluation of the fracture toughness in the transition region releases the overconservatism that has been observed in using the ASME-KIC curve. One main advantage of using the Master Curve methodology is possibility to use small Charpy-size specimens to determine fracture toughness. Detailed description of the Master Curve methodology is given by Sattari-Far and Wallin [2005). ProSACC is a suitable program in using for structural integrity assessments of components containing crack like defects and for defect tolerance analysis. The program gives possibilities to conduct assessments based on deterministic or probabilistic grounds. The method utilized in ProSACC is based on the R6-method developed at Nuclear Electric plc, Milne et al [1988]. The basic assumption in this method is that fracture in a cracked body can be described by two parameters Kr and Lr. The parameter Kr is the ratio between the stress intensity factor and the fracture toughness of the material. The parameter Lr is the ratio between applied load and the plastic limit load of the structure. The ProSACC assessment results are therefore highly dependent on the applied fracture toughness value in the assessment. In this work, the main options of the Master Curve methodology are implemented in the ProSACC program. Different options in evaluating Master Curve fracture toughness from standard fracture toughness testing data or impact testing data are considered. In addition, the
Implementation of the Master Curve method in ProSACC
International Nuclear Information System (INIS)
Feilitzen, Carl von; Sattari-Far, Iradj
2012-03-01
Cleavage fracture toughness data display normally large amount of statistical scatter in the transition region. The cleavage toughness data in this region is specimen size-dependent, and should be treated statistically rather than deterministically. Master Curve methodology is a procedure for mechanical testing and statistical analysis of fracture toughness of ferritic steels in the transition region. The methodology accounts for temperature and size dependence of fracture toughness. Using the Master Curve methodology for evaluation of the fracture toughness in the transition region releases the overconservatism that has been observed in using the ASME-KIC curve. One main advantage of using the Master Curve methodology is possibility to use small Charpy-size specimens to determine fracture toughness. Detailed description of the Master Curve methodology is given by Sattari-Far and Wallin [2005). ProSACC is a suitable program in using for structural integrity assessments of components containing crack like defects and for defect tolerance analysis. The program gives possibilities to conduct assessments based on deterministic or probabilistic grounds. The method utilized in ProSACC is based on the R6-method developed at Nuclear Electric plc, Milne et al [1988]. The basic assumption in this method is that fracture in a cracked body can be described by two parameters Kr and Lr. The parameter Kr is the ratio between the stress intensity factor and the fracture toughness of the material. The parameter Lr is the ratio between applied load and the plastic limit load of the structure. The ProSACC assessment results are therefore highly dependent on the applied fracture toughness value in the assessment. In this work, the main options of the Master Curve methodology are implemented in the ProSACC program. Different options in evaluating Master Curve fracture toughness from standard fracture toughness testing data or impact testing data are considered. In addition, the
Uncertainty Measures of Regional Flood Frequency Estimators
DEFF Research Database (Denmark)
Rosbjerg, Dan; Madsen, Henrik
1995-01-01
Regional flood frequency models have different assumptions regarding homogeneity and inter-site independence. Thus, uncertainty measures of T-year event estimators are not directly comparable. However, having chosen a particular method, the reliability of the estimate should always be stated, e...
DEFF Research Database (Denmark)
Lali-Dastjerdi, Zohreh; Cristofori, Valentina; Lund-Hansen, Toke
2012-01-01
This paper reports a comprehensive study of pump- to-signal intensity modulation transfer (IMT) in single-pump fiber optic parametric amplifiers (FOPAs). In particular, the IMT is studied for the first time for high-frequency fluctuations of the pump as well as in the saturated gain regime. The IMT...... cut-off frequency in typical single-pump FOPAs is around 100–200 GHz. The possibilities to shift this frequency based on dispersion and nonlinearities involved in the parametric gain are discussed. The severe IMT to the signal at low modulation frequencies can be suppressed by more than 50...
Directory of Open Access Journals (Sweden)
Luiz F. C. de Oliveira
2008-03-01
relations available to some municipal districts. It was also determined the relation between the precipitation of sixty minutes and one day duration for two years return period. The information obtained in this work was regionalized, allowing the generation of thematic aiming to estimate the rainfall height-duration-frequency relation for the places without registrations. The BellÂ’s model perfectly adjusted to the municipal districts that were studied, becoming an interesting alternative concerning to acquiring the height of intense rain from short series. The reconstruction of BellÂ’s model based on the regionalization of the adjusted parameters allowed the expansion of the equations that express the relation between the maximum precipitation for different durations and the return period with low values in the standard error of the estimate.
Danielle E. Marias; Frederick C. Meinzer; Christopher Still
2017-01-01
Given future climate predictions of increased temperature, and frequency and intensity of heat waves in the tropics, suitable habitat to grow ecologically, economically, and socially valuable Coffea arabica is severely threatened. We investigated how leaf age and heat stress duration impact recovery from heat stress in C. arabica...
Coutris, G
1981-12-01
Sixty-six patients with chronic myelogenous leukemia, all with Philadelphia chromosome, have been studied for chromosomic abnormalities associated (CAA) to Ph', as well as for actuarial curve of survivorship. Patients dying from another disease were excluded from this study. Frequency of cells with CAA was measured and appeared strongly higher after blastic transformation than during myelocytic state; probability to be a blastic transformation is closely correlated with this frequency. On the other hand, actuarial curve of survivorship is very well represented by an exponential curve. This suggests a constant rate of death during disease evolution, for these patients without intercurrent disease. As a mean survivance after blastic transformation is very shorter than myelocytic duration, a constant rate of blastic transformation could be advanced: it explains possible occurrence of transformation as soon as preclinic state of a chronic myelogenous leukemia. Even if CAA frequency increases after blastic transformation, CAA can occur a long time before it and do not explain it: submicroscopic origin should be searched for the constant rate of blastic transformation would express the risk of a genic transformation at a constant rate during myelocytic state.
Analysis of the radial distribution curves of partially ordered condensed carbon films
International Nuclear Information System (INIS)
Palatnik, L.S.; Derevyanchenko, A.S.; Nechitajlo, A.A.; Stetsenko, A.N.; Gorbenko, N.I.
1977-01-01
The Fourier analysis of the electron scattering curves has been carried out to determine the short-range order structure of carbon condensates. The intensity curves for carbon films condensed in a approximately 10 -6 Torr vacuum upon a substrate heated up to 600 deg C were obtained by diffraction techniques with filtration of the inelastic scattered electron background. The radial distribution curve errors were analyzed and quantified with the aid of a computer to determine the short-range order of the condensed carbon. It has been shown that carbon films consist of regions measuring approximately 20 A formed by parallelly packed graphite nets with azimuthal orientation different from that in ideal graphite crystals
A space-time hybrid hourly rainfall model for derived flood frequency analysis
Directory of Open Access Journals (Sweden)
U. Haberlandt
2008-12-01
Full Text Available For derived flood frequency analysis based on hydrological modelling long continuous precipitation time series with high temporal resolution are needed. Often, the observation network with recording rainfall gauges is poor, especially regarding the limited length of the available rainfall time series. Stochastic precipitation synthesis is a good alternative either to extend or to regionalise rainfall series to provide adequate input for long-term rainfall-runoff modelling with subsequent estimation of design floods. Here, a new two step procedure for stochastic synthesis of continuous hourly space-time rainfall is proposed and tested for the extension of short observed precipitation time series.
First, a single-site alternating renewal model is presented to simulate independent hourly precipitation time series for several locations. The alternating renewal model describes wet spell durations, dry spell durations and wet spell intensities using univariate frequency distributions separately for two seasons. The dependence between wet spell intensity and duration is accounted for by 2-copulas. For disaggregation of the wet spells into hourly intensities a predefined profile is used. In the second step a multi-site resampling procedure is applied on the synthetic point rainfall event series to reproduce the spatial dependence structure of rainfall. Resampling is carried out successively on all synthetic event series using simulated annealing with an objective function considering three bivariate spatial rainfall characteristics. In a case study synthetic precipitation is generated for some locations with short observation records in two mesoscale catchments of the Bode river basin located in northern Germany. The synthetic rainfall data are then applied for derived flood frequency analysis using the hydrological model HEC-HMS. The results show good performance in reproducing average and extreme rainfall characteristics as well as in
Directory of Open Access Journals (Sweden)
Wenbin Mu
2015-06-01
Full Text Available The rainfall-runoff process (RRP is an important part of hydrologic process. There is an effective measure to study RRP through artificial rainfall simulation. This paper describes a study on three growing stages (jointing stage, tasseling stage, and mature stage of spring maize in which simulated rainfall events were used to study the effects of various factors (rainfall intensity and slope gradient on the RRP. The RRP was tested with three different rainfall intensities (0.67, 1.00, and 1.67 mm/min and subjected to three different slopes (5°, 15°, and 20° so as to study RRP characteristics in semiarid regions. Regression analysis was used to study the results of this test. The following key results were obtained: (1 With the increase in rainfall intensity and slope, the increasing relationship with rainfall duration, overland flow, and cumulative runoff, respectively, complied with logarithmic and quadratic functions before reaching stable runoff in each growing stage of spring maize; (2 The runoff coefficient increased with the increase in rainfall intensity and slope in each growing stages of spring maize. The relationship between runoff coefficient, slope, rainfall intensity, rainfall duration, antecedent soil moisture, and vegetation coverage was multivariate and nonlinear; (3 The runoff lag time decreased with the increase in rainfall intensity and slope within the same growing stage. In addition, the relationship between runoff lag time, slope, rainfall intensity, antecedent soil moisture, and vegetation coverage could also be expressed by a multivariate nonlinear equation; (4 The descent rate of soil infiltration rate curve increased with the increased rainfall intensity and slope in the same growing stage. Furthermore, by comparing the Kostiakov, Horton, and Philip models, it was found that the Horton infiltration model was the best for estimating soil infiltration rate and cumulative infiltration under the condition of test.
Gibbs, James F.; Borcherdt, Roger D.
1974-01-01
Measurements of ground motion generated by nuclear explosions in Nevada have been completed for 99 locations in the San Francisco Bay region, California. The seismograms, Fourier amplitude spectra, spectral amplification curves for the signal, and the Fourier amplitude spectra of the seismic noise are presented for 60 locations. Analog amplifications, based on the maximum signal amplitude, are computed for an additional 39 locations. The recordings of the nuclear explosions show marked amplitude variations which are consistently related to the local geologic conditions of the recording site. The average spectral amplifications observed for vertical and horizontal ground motions are, respectively: (1, 1) for granite, (1.5, 1.6) for the Franciscan Formation, (2.3, 2.3), for other pre-Tertiary and Tertiary rocks, (3.0, 2.7) for the Santa Clara Formation, (3.3, 4.4) for older bay sediments, and (3.7, 11.3) for younger bay mud. Spectral amplification curves define predominant ground frequencies for younger bay mud sites and for some older bay sediment sites. The predominant frequencies for most sites were not clearly defined by the amplitude spectra computed from the seismic background noise. The intensities ascribed to various sites in the San Francisco Bay region for the California earthquake of April 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the intensities for 917 sites on Franciscan rocks generally decrease with the logarithm of distance as Intensity = 2.69 - 1.90 log (Distance Km). For sites on other geologic units, intensity increments, derived from this empirical rela.tion, correlate strongly with the Average Horizontal Spectral Amplifications (MISA) according to the empirical relation Intensity Increment= 0.27 + 2.70 log(AHSA). Average
Yoo, Kyoung-Hun; Shin, Dong-Wook; Cho, Mi-Hee; Kim, Sang-Hyuck; Bahk, Hyun-Jung; Kim, Shin-Hye; Jeong, Su-Min; Yun, Jae-Moon; Park, Jin-Ho; Kim, Heesun; Cho, BeLong
2017-09-01
Suboptimal frequency of glycosylated hemoglobin (HbA1c) monitoring is associated with poor diabetes control. We aimed to analyze compliance to HbA1c testing guidelines and explore associated individual and area-level determinants, focusing on regional variation. This cross-sectional study between the period of 2012-2013 was conducted by using the Korean National Health Insurance Research Database, and included 45,634 patients diagnosed with diabetes mellitus, who were prescribed any anti-diabetic medications, including insulin. We calculated the proportion of each HbA1c testing frequency (≥1, ≥2, or ≥4 times per year) stratified by 17 administrative regions. Multilevel and multivariate logistic analyses were performed with regional (proportion of farmer population) and individual characteristics (age, sex, income level, duration of diabetes, and most visited medical institution). Overall, 67.3% of the patients received≥1 HbA1c test per year; 37.8% and 6.1% received ≥2 and ≥4 tests per year, respectively. Those managed in secondary-level hospitals or clinics and those living in rural areas were less likely to receive HbA1c testing. Even after adjusting for individual and regional level characteristics, significant area level variation was observed (variance participant coefficients were 7.91%, 9.58%, and 14.43% for testing frequencies of ≥1, ≥2, and ≥4 times a year, respectively). The frequency of HbA1c monitoring is suboptimal in Korea, especially in rural areas. Moreover, significant regional variation was observed, implying a contextual effect. This suggests the need for developing policy actions to improve HbA1c monitoring. In particular, access to HbA1c testing in rural primary care clinics must be improved. Copyright © 2017 Elsevier B.V. All rights reserved.
Noise Measurement and Frequency Analysis of Commercially Available Noisy Toys
Directory of Open Access Journals (Sweden)
Shohreh Jalaie
2005-06-01
Full Text Available Objective: Noise measurement and frequency analysis of commercially available noisy toys were the main purposes of the study. Materials and Methods: 181 noisy toys commonly found in toy stores in different zones of Tehran were selected and categorized into 10 groups. Noise measurement were done at 2, 25, and 50 cm from toys in dBA. The noisiest toy of each group was frequency analyzed in octave bands. Results: The highest and the lowest intensity levels belonged to the gun (mean=112 dBA and range of 100-127 dBA and to the rattle-box (mean=84 dBA and range of 74-95 dBA, respectively. Noise intensity levels significantly decreased with increasing distance except for two toys. Noise frequency analysis indicated energy in effective hearing frequencies. Most of the toys energies were in the middle and high frequency region. Conclusion: As intensity level of the toys is considerable, mostly more than 90 dBA, and also their energy exist in the middle and high frequency region, toys should be considered as a cause of the hearing impairment.
Guzman-Morales, J.; Gershunov, A.
2015-12-01
Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region. In spite of their tremendous episodic impacts on the health, economy and mood of the region, climate-scale behavior of SAW is poorly understood. In the present work, we identify SAWs in mesoscale dynamical downscaling of a global reanalysis product and construct an hourly SAW catalogue spanning 65 years. We describe the long-term SAW climatology at relevant time-space resolutions, i.e, we developed local and regional SAW indices and analyse their variability on hourly, daily, annual, and multi-decadal timescales. Local and regional SAW indices are validated with available anemometer observations. Characteristic behaviors are revealed, e.g. the SAW intensity-duration relationship. At interdecadal time scales, we find that seasonal SAW activity is sensitive to prominent large-scale low-frequency modes of climate variability rooted in the tropical and north Pacific ocean-atmosphere system that are also known to affect the hydroclimate of this region. Lastly, we do not find any long-term trend in SAW frequency and intensity as previously reported. Instead, we identify a significant long-term trend in SAW behavior whereby contribution of extreme SAW events to total seasonal SAW activity has been increasing at the expense of moderate events. These findings motivate further investigation on SAW evolution in future climate and its impact on wildfires.
International Nuclear Information System (INIS)
Ullah, H.; Akhtar, N.; Matee, S.; Butt, A.W.
2015-01-01
The purpose of this study was to determine frequency, character, approximate location and intensity of neuropathic pain in spinal cord injury and its impact on the quality of life. Study Design: A cross-sectional survey Place and Duration of Study: Armed Forces Institute of Rehabilitation Medicine (AFIRM), Rawalpindi from Feb 2009 to Feb 2010. Material and Methods: Through non-probability convenience sampling 87 patients of both genders diagnosed with spinal cord injury based on American Spinal Injury Association criteria and admitted within a year of injury were included. Those in spinal shock, having poor cognition, inability to communicate, concurrent brain injury and history of chronic pain before injury were excluded. The history, localization and characteristics of the pain and interference with life activities were recorded. Neuropathic pain of patients was evaluated with Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale. Visual analogue scale was used to measure the severity of pain. Results: Out of 87 patients (mean age 36.9 years) seventy four were male and 13 were female. Seventy patients (80%) were AIS-A, 6 (7%) were AIS-B and 11 (13%) were AIS-C. Neuropathic pain was present in 57.5% (n=50). Most of the patients localized their pain below the neurological level of injury (78%) and rated pain intensity as moderate pain (54%). Majority (48%) described the pain as burning followed by electric shock like (42%), stabbing (8%) and pricking (2%). 48% patients reported that their quality of life was affected due to pain. 52% required two analgesics of different groups to relieve pain followed by 40% requiring three analgesics and 8% requiring one analgesic. Conclusion: Neuropathic pain is prevalent in people with spinal cord injury and adversely affects life quality. Neuropathic pain is primarily described as a burning sensation of moderate intensity mostly referred to below the neurological level of injury. (author)
Regional Myocardial Blood Volume and Flow: First-Pass MR Imaging with Polylysine-Gd-DTPA
Wilke, Norbert; Kroll, Keith; Merkle, Hellmut; Wang, Ying; Ishibashi, Yukata; Xu, Ya; Zhang, Jiani; Jerosch-Herold, Michael; Mühler, Andreas; Stillman, Arthur E.; Bassingthwaighte, James B.; Bache, Robert; Ugurbil, Kamil
2010-01-01
The authors investigated the utility of an intravascular magnetic resonance (MR) contrast agent, poly-L-lysine-gadolinium diethylenetriaminepentaacetic acid (DTPA), for differentiating acutely ischemic from normally perfused myocardium with first-pass MR imaging. Hypoperfused regions, identified with microspheres, on the first-pass images displayed significantly decreased signal intensities compared with normally perfused myocardium (P < .0007). Estimates of regional myocardial blood content, obtained by measuring the ratio of areas under the signal intensity-versus-time curves in tissue regions and the left ventricular chamber, averaged 0.12 mL/g ± 0.04 (n = 35), compared with a value of 0.11 mL/g ± 0.05 measured with radiolabeled albumin in the same tissue regions. To obtain MR estimates of regional myocardial blood flow, in situ calibration curves were used to transform first-pass intensity-time curves into content-time curves for analysis with a multiple-pathway, axially distributed model. Flow estimates, obtained by automated parameter optimization, averaged 1.2 mL/min/g ± 0.5 [n = 29), compared with 1.3 mL/min/g ± 0.3 obtained with tracer microspheres in the same tissue specimens at the same time. The results represent a combination of T1-weighted first-pass imaging, intravascular relaxation agents, and a spatially distributed perfusion model to obtain absolute regional myocardial blood flow and volume. PMID:7766986
Shekhawat, Giriraj Singh; Sundram, Frederick; Bikson, Marom; Truong, Dennis; De Ridder, Dirk; Stinear, Cathy M; Welch, David; Searchfield, Grant D
2016-05-01
Tinnitus is the perception of a phantom sound. The aim of this study was to compare current intensity (center anode 1 mA and 2 mA), duration (10 minutes and 20 minutes), and location (left temporoparietal area [LTA] and dorsolateral prefrontal cortex [DLPFC]) using 4 × 1 high-definition transcranial direct current stimulation (HD-tDCS) for tinnitus reduction. Twenty-seven participants with chronic tinnitus (>2 years) and mean age of 53.5 years underwent 2 sessions of HD-tDCS of the LTA and DLPFC in a randomized order with a 1 week gap between site of stimulation. During each session, a combination of 4 different settings were used in increasing dose (1 mA, 10 minutes; 1 mA, 20 minutes; 2 mA, 10 minutes; and 2 mA, 20 minutes). The impact of different settings on tinnitus loudness and annoyance was documented. Twenty-one participants (77.78%) reported a minimum of 1 point reduction on tinnitus loudness or annoyance scales. There were significant changes in loudness and annoyance for duration of stimulation,F(1, 26) = 10.08,Ptinnitus relief. The stimulation of the LTA and DLPFC were equally effective for suppressing tinnitus loudness and annoyance. © The Author(s) 2015.
Iryanov, Y M; Kiryanov, N A
2015-01-01
Non-drug correction of reparative bone tissue regeneration in different pathological states - one of the most actual problems of modern medicine. Our aim was to conduct morphological analysis of the influence of electromagnetic radiation of ultra-high frequency and low intensity on reparative osteogenesis and angiogenesis in fracture treatment under transosseous osteosynthesis. A controlled nonrandomized study was carried out. In the experiment conducted on rats we modeled tibial fracture with reposition and fixation of the bone fragments both in control and experimental groups. In the animals of the experimental group the fracture zone was exposed to low intensity electromagnetic radiation of ultra-high frequency. Exposure simulation was performed in the control group. The operated bones were examined using radiography, light and electronic microscopy, X-ray electronic probe microanalysis. It has been established that electromagnetic radiation of ultra-high frequency sessions in fracture treatment stimulate secretory activity and degranulation of mast cells, produce microcirculatory bed vascular permeability increase, endotheliocyte migration phenotype expression, provide endovascular endothelial outgrowth formation, activate reparative osteogenesis and angiogenesis while fracture reparation becomes the one of the primary type. The full periosteal, intermediary and intraosteal bone union was defined in 28 days. Among the therapeutic benefits of electromagnetic radiation of ultra-high frequency in fracture treatment we can detect mast cell secretorv activity stimulation and endovascular anziozenesis activation.
Sabatier, Pierre; Wilhelm, Bruno; Ficetola, Gentile Francesco; Moiroux, Fanny; Poulenard, Jérôme; Develle, Anne-Lise; Bichet, Adeline; Chen, Wentao; Pignol, Cécile; Reyss, Jean-Louis; Gielly, Ludovic; Bajard, Manon; Perrette, Yves; Malet, Emmanuel; Taberlet, Pierre; Arnaud, Fabien
2017-08-01
The high-resolution sedimentological and geochemical analysis of a sediment sequence from Lake Savine (Western Mediterranean Alps, France) led to the identification of 220 event layers for the last 6000 years. 200 were triggered by flood events and 20 by underwater mass movements possibly related to earthquakes that occurred in 5 clusters of increase seismicity. Because human activity could influence the flood chronicle, the presence of pastures was reconstructed through ancient DNA, which suggested that the flood chronicle was mainly driven by hydroclimate variability. Weather reanalysis of historical floods allow to identify that mesoscale precipitation events called "East Return" events were the main triggers of floods recorded in Lake Savine. The first part of this palaeoflood record (6-4 kyr BP) was characterized by increases in flood frequency and intensity in phase with Northern Alpine palaeoflood records. By contrast, the second part of the record (i.e., since 4 kyr BP) was phased with Southern Alpine palaeoflood records. These results suggest a palaeohydrological transition at approximately 4 kyr BP, as has been previously described for the Mediterranean region. This may have resulted in a change of flood-prone hydro-meteorological processes, i.e., in the balance between occurrence and intensity of local convective climatic phenomena and their influence on Mediterranean mesoscale precipitation events in this part of the Alps. At a centennial timescale, increases in flood frequency and intensity corresponded to periods of solar minima, affecting climate through atmospheric changes in the Euro-Atlantic sector.
Estimating regional centile curves from mixed data sources and countries.
van Buuren, Stef; Hayes, Daniel J; Stasinopoulos, D Mikis; Rigby, Robert A; ter Kuile, Feiko O; Terlouw, Dianne J
2009-10-15
Regional or national growth distributions can provide vital information on the health status of populations. In most resource poor countries, however, the required anthropometric data from purpose-designed growth surveys are not readily available. We propose a practical method for estimating regional (multi-country) age-conditional weight distributions based on existing survey data from different countries. We developed a two-step method by which one is able to model data with widely different age ranges and sample sizes. The method produces references both at the country level and at the regional (multi-country) level. The first step models country-specific centile curves by Box-Cox t and Box-Cox power exponential distributions implemented in generalized additive model for location, scale and shape through a common model. Individual countries may vary in location and spread. The second step defines the regional reference from a finite mixture of the country distributions, weighted by population size. To demonstrate the method we fitted the weight-for-age distribution of 12 countries in South East Asia and the Western Pacific, based on 273 270 observations. We modeled both the raw body weight and the corresponding Z score, and obtained a good fit between the final models and the original data for both solutions. We briefly discuss an application of the generated regional references to obtain appropriate, region specific, age-based dosing regimens of drugs used in the tropics. The method is an affordable and efficient strategy to estimate regional growth distributions where the standard costly alternatives are not an option. Copyright (c) 2009 John Wiley & Sons, Ltd.
Fischer, Jennifer; Ortel, Marlen; Hagmann, Sebastien; Hoeflich, Andreas; Richter, Wiltrud
2016-12-01
Generation of phenotypically stable, articular chondrocytes from mesenchymal stromal cells (MSCs) is still an unaccomplished task, with formation of abundant, hyaline extracellular matrix, and avoidance of hypertrophy being prime challenges. We recently demonstrated that parathyroid hormone-related protein (PTHrP) is a promising factor to direct chondrogenesis of MSCs towards an articular phenotype, since intermittent PTHrP application stimulated cartilage matrix production and reduced undesired hypertrophy. We here investigated the role of frequency, pulse duration, total exposure time, and underlying mechanisms in order to unlock the full potential of PTHrP actions. Human MSC subjected to in vitro chondrogenesis for six weeks were exposed to 2.5 nM PTHrP(1-34) pulses from days 7 to 42. Application frequency was increased from three times weekly (3 × 6 h/week) to daily maintaining either the duration of individual pulses (6 h/day) or total exposure time (18 h/week; 2.6 h/day). Daily PTHrP treatment significantly increased extracellular matrix deposition regardless of pulse duration and suppressed alkaline-phosphatase activity by 87%. High total exposure time significantly reduced cell proliferation at day 14. Pulse duration was critically important to significantly reduce IHH expression, but irrelevant for PTHrP-induced suppression of the hypertrophic markers MEF2C and IBSP. COL10A1, RUNX2, and MMP13 expression remained unaltered. Decreased IGFBP-2, -3, and -6 expression suggested modulated IGF-I availability in PTHrP groups, while drop of SOX9 protein levels during the PTHrP-pulse may delay chondroblast formation and hypertrophy. Overall, the significantly optimized timing of PTHrP-pulses demonstrated a vast potential to enhance chondrogenesis of MSC and suppress hypertrophy possibly via superior balancing of IGF- and SOX9-related mechanisms. J. Cell. Physiol. 231: 2673-2681, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Lymans'kyĭ, Iu P; Tamarova, Z A; Huliar, S O
2003-01-01
In experiments on mice, statistically authentic weakening of visceral pain has been shown after an action of low intensity polarized light from a device Bioptron on antinociceptive acupuncture points (AP). Pain was caused by an intraperitoneal injection of 2% acetic acid (0.1 ml/10 g). The intensity of pain was judged on duration and frequency of painful behavioral reactions (writhing, licking of abdomen), as well as on duration of sleep, eating and motor activity. In animals which immediately after injections of acetic acid were exposed to polarized light of low intensity for 10 min, applied on any of antinociceptive APs (E-36, E-43, VC-8, RP-6), the duration of painful behavioral reaction was determined to be reduced, while that of non-painful one increased. The comparison of the total duration of the writhing at control and experimental mice showed that an activation of AP E-43 induced the greatest analgesic effect (76.5%), from AP VC-8 it was 76.3%, from RP-6--46.8%, and from E-36--41.4%. We have concluded that the effect of polarized light of low intensity on APs was a convenient non-pharmacological method of treating visceral pain.
Bozkurt, S.; Stein, R.; Toda, S.
2006-12-01
The long recorded history of earthquakes in Japan affords an opportunity to forecast seismic shaking exclusively from past observations of shaking. For this we analyzed 10,000 intensity observations recorded during AD 1600-2000 in a 350 x 350 km area centered on Tokyo in a Geographic Information System. A frequency-intensity curve is found for each 5 x 5 km cell, and from this the probability of exceeding any intensity level can be estimated. The principal benefits of this approach is that it builds the fewest possible assumptions into a probabilistic seismic forecast, it includes site and source effects without imposing this behavior, and we do not need to know the size or location of any earthquake or the location and slip rate of any fault. The cost is that we must abandon any attempt to make a time-dependent forecast, which could be quite different. We believe the method is suitable to many applications of probabilistic seismic hazard assessment, and to other regions. The two key assumptions are that the slope of the observed frequency-intensity relation at every site is the same, and that the 400-year record is long enough to encompass the full range of seismic behavior. Tests we conduct suggest that both assumptions are sound. The resulting 30-year probability of IJMA>=6 shaking (roughly equivalent to PGA>=0.9 g or MMI=IX-X) is 30-40% in Tokyo, Kawasaki, and Yokohama, and 10-15% in Chiba and Tsukuba, the range reflecting spatial variability and curve-fitting alternatives. The strongest shaking is forecast along the margins of Tokyo Bay, within the river sediments extending northwest from Tokyo, and at coastal sites near the plate boundary faults. We also produce long- term exceedance maps of peak ground acceleration for building code regulations, and short-term hazard maps associated with hypothetical catastrophe bonds. Our results for greater Tokyo resemble our independent Poisson probability developed from conventional seismic hazard analysis, as well as
Learning to love the rain in Bergen (Norway) and other lessons from a Climate Services neophyte
Sobolowski, Stefan; Wakker, Joyce
2014-05-01
slice under the rcp4.5 "middle of the road" emissions scenario (2071-2100). A unique feature of the WRF modeling system is the ability to write data for selected locations at every time step, thus creating time series of very high temporal resolution which can be compared to observations. This high temporal resolution also allowed us to directly calculate intensity-duration-frequency (IDF) curves for intense precipitation of short to long duration (5 minutes - 1 day) for a number of return periods (2-100 years) with out resorting to factors to calculate rainfall intensities at higher temporal resolutions, as is commonly done. We investigated the IDF curves using a number of parametric and non-parametric approaches. Given the relatively short time periods of the modeled data the standard Gumble approach is presented here. This is also done to maintain consistency with previous calculations by the water and drain administration. Curves were also generated from observed time series at two locations in Bergen. Both the historical, GCM-driven simulation and the ERA-interim driven simulation closely match the observed IDF curves for all return periods up to durations of about 10 minutes where WRF then fails to reproduce the very short, very high intensity events. IDF curves under future conditions were also generated and the changes were compared with the current standard approach of applying climate change-factors to observed extreme precipitation in order to account for structural errors in global and regional climate models. Our investigation suggests that high-resolution regional simulations can capture many of the topographic features and dynamical processes necessary to accurately model extreme rainfall, even in at highly local scales and over complex terrain such as Bergen, Norway. The exercise also produced many lessons for climate service providers and users alike.
Poretti, Ennio
1997-01-01
The recent results (Pardo & Poretti 1997, A&A 324, 121; Poretti & Pardo 1997, A&A 324, 133) obtained on the frequency content of Double-Mode Cepheids light curves and the properties of their Fourier parameters are reviewed. Some points briefly discussed in previous papers (no third periodicity, methodological aspects on the true peaks detection, the action of the cross coupling terms and the impact on theoretical models) are described.
International Nuclear Information System (INIS)
Chen, Zhiyun; Bai, Yongliang; Yin, Tianxiang; An, Xueqin; Shen, Weiguo
2012-01-01
Highlights: ► Coexistence curves of (benzonitrile + n-pentadecane) and (benzonitrile + n-heptadecane) were measured. ► The values of the critical exponent β are consistent with that predicted by the 3D-Ising model. ► The coexistence curves are well described by the critical crossover model. ► The asymmetry of the diameters of the coexistence curves were discussed by the complete scaling theory. - Abstract: Liquid + liquid coexistence curves for the binary solutions of {benzonitrile + n-pentadecane} and {benzonitrile + n-heptadecane} have been measured in the critical region. The critical exponent β and the critical amplitudes have been deduced and the former is consistent with the theoretic prediction. It was found that the coexistence curves may be well described by the crossover model proposed by Gutkowski et al. The asymmetries of the diameters of the coexistence curves were also discussed in the frame of the complete scaling theory.
International Nuclear Information System (INIS)
Mantovani, M.S.M.; Stewart, K.; Turner, S.; Hawkesworth, C.J.
1995-01-01
Duration of Continental Floods Basalts magmatism has generally been considered to be extremely short. Ar-Ar data for different magma type, over a broad region within Parana, demonstrate a duration of 10 Ma, an order of magnitude greater than the usually accepted duration of magmatism. The dating method included rigorous geochemical selection tests, to discard altered samples, combined with the analysis of laser spot technique using the isochron approach. This methodology allows discrimination between rocks which yield precise ages and those which are too altered or heterogeneous. The agreement between the determined age and the relative stratigraphic position of samples supports the above statement. 4 figs
Energy Technology Data Exchange (ETDEWEB)
Mantovani, M.S.M. [Sao Paulo Univ., SP (Brazil). Inst. Astronomico e Geofisico; Stewart, K.; Turner, S.; Hawkesworth, C.J. [Open Univ., Milton Keynes (United Kingdom). Dept. of Earth Sciences
1995-12-31
Duration of Continental Floods Basalts magmatism has generally been considered to be extremely short. Ar-Ar data for different magma type, over a broad region within Parana, demonstrate a duration of 10 Ma, an order of magnitude greater than the usually accepted duration of magmatism. The dating method included rigorous geochemical selection tests, to discard altered samples, combined with the analysis of laser spot technique using the isochron approach. This methodology allows discrimination between rocks which yield precise ages and those which are too altered or heterogeneous. The agreement between the determined age and the relative stratigraphic position of samples supports the above statement. 4 figs.
Intensity and directionality of bat echolocation signals
DEFF Research Database (Denmark)
Jakobsen, Lasse; Brinkløv, Signe; Surlykke, Annemarie
2013-01-01
will increase signal directionality in the field along with intensity thus increasing sonar range. During the last phase of prey pursuit, vespertilionid bats broaden their echolocation beam considerably, probably to counter evasive maneuvers of eared prey. We highlight how multiple call parameters (frequency......The paper reviews current knowledge of intensity and directionality of bat echolocation signals. Recent studies have revealed that echolocating bats can be much louder than previously believed. Bats previously dubbed "whispering" can emit calls with source levels up to 110 dB SPL at 10 cm......, duration, intensity, and directionality of echolocation signals) in unison define the search volume probed by bats and in turn how bats perceive their surroundings. Small changes to individual parameters can, in combination, drastically change the bat's perception, facilitating successful navigation...
International Nuclear Information System (INIS)
Sei, Norihiro; Kuroda, Ryunosuke; Yasumoto, Masato; Toyokawa, Hiroyuki; Ogawa, Hiroshi; Koike, Masaki; Yamada, Kawakatsu
2008-01-01
We measured intense radiation from an electron bunch in a millimeter wave region using the compact S-band linac. The dependence of the radiation on the electron-bunch charge was measured with an rf detector system at frequencies around 0.1 THz and was confirmed to be a coherent synchrotron radiation (CSR). The total power of the horizontally and vertically polarized CSRs, which were extracted through the Z-cut quartz window within 1 ns, was calculated to be about 88 and 30 nJ/pulse, excluding the absorption by the window. The two-dimensional distribution of the vertically polarized CSR was measured at a distance of about 0.7 m from the radiation point. The CSR distribution was comparatively uniform in the horizontal plane. Intense CSR, which was reflected in the vacuum chamber, was extracted with a delay of about 6 ns. This suggests that measurement of temporal structure is needed for CSR applications
Guan, Kaiyu; Good, Stephen P.; Caylor, Kelly K.; Medvigy, David; Pan, Ming; Wood, Eric F.; Sato, Hisashi; Biasutti, Michela; Chen, Min; Ahlström, Anders; Xu, Xiangtao
2018-02-01
There is growing evidence of ongoing changes in the statistics of intra-seasonal rainfall variability over large parts of the world. Changes in annual total rainfall may arise from shifts, either singly or in a combination, of distinctive intra-seasonal characteristics -i.e. rainfall frequency, rainfall intensity, and rainfall seasonality. Understanding how various ecosystems respond to the changes in intra-seasonal rainfall characteristics is critical for predictions of future biome shifts and ecosystem services under climate change, especially for arid and semi-arid ecosystems. Here, we use an advanced dynamic vegetation model (SEIB-DGVM) coupled with a stochastic rainfall/weather simulator to answer the following question: how does the productivity of ecosystems respond to a given percentage change in the total seasonal rainfall that is realized by varying only one of the three rainfall characteristics (rainfall frequency, intensity, and rainy season length)? We conducted ensemble simulations for continental Africa for a realistic range of changes (-20% ~ +20%) in total rainfall amount. We find that the simulated ecosystem productivity (measured by gross primary production, GPP) shows distinctive responses to the intra-seasonal rainfall characteristics. Specifically, increase in rainfall frequency can lead to 28% more GPP increase than the same percentage increase in rainfall intensity; in tropical woodlands, GPP sensitivity to changes in rainy season length is ~4 times larger than to the same percentage changes in rainfall frequency or intensity. In contrast, shifts in the simulated biome distribution are much less sensitive to intra-seasonal rainfall characteristics than they are to total rainfall amount. Our results reveal three major distinctive productivity responses to seasonal rainfall variability—‘chronic water stress’, ‘acute water stress’ and ‘minimum water stress’ - which are respectively associated with three broad spatial patterns of
F(α) curves: Experimental results
International Nuclear Information System (INIS)
Glazier, J.A.; Gunaratne, G.; Libchaber, A.
1988-01-01
We study the transition to chaos at the golden and silver means for forced Rayleigh-Benard (RB) convection in mercury. We present f(α) curves below, at, and above the transition, and provide comparisons to the curves calculated for the one-dimensional circle map. We find good agreement at both the golden and silver means. This confirms our earlier observation that for low amplitude forcing, forced RB convection is well described by the one-dimensional circle map and indicates that the f(α) curve is a good measure of the approach to criticality. For selected subcritical experimental data sets we calculate the degree of subcriticality. We also present both experimental and calculated results for f(α) in the presence of a third frequency. Again we obtain agreement: The presence of random noise or a third frequency narrows the right-hand (negative q) side of the f(α) curve. Subcriticality results in symmetrically narrowed curves. We can also distinguish these cases by examining the power spectra and Poincare sections of the time series
Groot, de H.L.F.; Withagen, C.A.A.M.; Minliang, Z.
2001-01-01
This paper addresses the existence of an Environmental Kuznets Curve for China, using a sample of thirty regions, covering the period 1982–1997. The types of pollution included are wastewater, waste gas and solid waste. We consider the development of the sources of pollution in a pooled
Bostock, M. G.; Thomas, A.; Rubin, A. M.; Savard, G.; Chuang, L. Y.
2015-12-01
We employ 130 low-frequency-earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from 100's to 1000's of individual LFEs, representing over 300,000 independent detections from major episodic-tremor-and- slip (ETS) events between 2003 and 2013. Template displacement waveforms for direct P- and S-waves at near epicentral distances are remarkably simple at many stations, approaching the zero-phase, single pulse expected for a point dislocation source in a homogeneous medium. High spatio-temporal precision of template match-filtered detections facilitates precise alignment of individual LFE detections and analysis of waveforms. Upon correction for 1-D geometrical spreading, attenuation, free-surface magnification and radiation pattern, we solve a large, sparse linear system for 3-D path corrections and LFE magnitudes for all detections corresponding to a single ETS template. The spatio-temporal distribution of magnitudes indicates that typically half the total moment release occurs within the first 12-24 hours of LFE activity during an ETS episode when tidal sensitity is low. The remainder is released in bursts over several days, particularly as spatially extensive RTRs, during which tidal sensitivity is high. RTR's are characterized by large magnitude LFEs, and are most strongly expressed in the updip portions of the ETS transition zone and less organized at downdip levels. LFE magnitude-frequency relations are better described by power-law than exponential distributions although they exhibit very high b-values ≥ 6. We examine LFE moment-duration scaling by generating templates using detections for limiting magnitude ranges MW<1.5, MW≥ 2.0. LFE duration displays a weaker dependence upon moment than expected for self-similarity, suggesting that LFE asperities are limited in dimension and that moment variation is dominated by slip. This behaviour implies
Conard, S. G.; Kukavskaya, E. A.; Buryak, L. V.; Shvetsov, E.; Kalenskaya, O. P.; Zhila, S.
2017-12-01
The Zabaikal region of southern Siberia is characterized by some of the highest fire activity in Russia. There has been a significant increase of fire frequency and burned area in the region over the last two decades due to a combination of high anthropogenic pressure, decreased funding to the forestry sector, and increased fire danger, which was associated with higher frequency and intensity of extreme weather events. Central and southern parts of the Zabaikal region where population density is higher and road network is relatively more developed are the most disturbed by fires. Larch stands cover the largest proportion of fire-disturbed lands in the region, while the less common pine and birch stands are characterized by higher fire frequency. About 13% (3.9 M ha) of the total forest area in the Zabaikal region was burned more than once in the 20 years from 1996 to 2015, with many sites burned multiple times. Repeat disturbances led to inadequate tree regeneration on all but the moistest sites. Pine stands on dry soils, which are common in the forest-steppe zone, were the most vulnerable. After repeat burns and over large burned sites we observed transformation of the forests to steppe ecosystems. The most likely causes of insufficient forest regeneration are soil overheating, dominance of tall grasses, and lack of nearby seed sources. Extensive tree plantations have potential to mitigate negative fire impacts; however, due to high fire hazard in the recent decade about half of the plantation area has been burned. Changes in the SWVI index were used to assess postfire reforestation based on a combination of satellite and field data. In the southwestern part of the Zabaikal region, we estimated that reforestation had been hampered over 11% of the forest land area. Regional climate models project increasing temperatures and decreasing precipitation across Siberia by the end of the 21st century, with changes in the Zabaikal region projected to be more than twice the
Evans, Lauren Jayne; Beck, Alison; Burdett, Mark
2017-09-01
regulation model of therapy duration, suggesting an individualized approach to therapy cessation as opposed to therapy session limits as the number of sessions a patient experienced was not generally associated with outcome. We found that clients with a diagnosis of a behavioural syndrome (F50-59) had less 'intensive' therapy; they experienced the same number of sessions over a longer time frame. Despite this, there were no associations between diagnosis category and change in score. © 2017 The British Psychological Society.
Duque, Daniel; Wang, Xin; Nieto-Diego, Javier; Krumbholz, Katrin; Malmierca, Manuel S.
2016-01-01
Electrophysiological and psychophysical responses to a low-intensity probe sound tend to be suppressed by a preceding high-intensity adaptor sound. Nevertheless, rare low-intensity deviant sounds presented among frequent high-intensity standard sounds in an intensity oddball paradigm can elicit an electroencephalographic mismatch negativity (MMN) response. This has been taken to suggest that the MMN is a correlate of true change or “deviance” detection. A key question is where in the ascending auditory pathway true deviance sensitivity first emerges. Here, we addressed this question by measuring low-intensity deviant responses from single units in the inferior colliculus (IC) of anesthetized rats. If the IC exhibits true deviance sensitivity to intensity, IC neurons should show enhanced responses to low-intensity deviant sounds presented among high-intensity standards. Contrary to this prediction, deviant responses were only enhanced when the standards and deviants differed in frequency. The results could be explained with a model assuming that IC neurons integrate over multiple frequency-tuned channels and that adaptation occurs within each channel independently. We used an adaptation paradigm with multiple repeated adaptors to measure the tuning widths of these adaption channels in relation to the neurons’ overall tuning widths. PMID:27066835
Optimal depth-based regional frequency analysis
Wazneh, H.; Chebana, F.; Ouarda, T. B. M. J.
2013-06-01
Classical methods of regional frequency analysis (RFA) of hydrological variables face two drawbacks: (1) the restriction to a particular region which can lead to a loss of some information and (2) the definition of a region that generates a border effect. To reduce the impact of these drawbacks on regional modeling performance, an iterative method was proposed recently, based on the statistical notion of the depth function and a weight function φ. This depth-based RFA (DBRFA) approach was shown to be superior to traditional approaches in terms of flexibility, generality and performance. The main difficulty of the DBRFA approach is the optimal choice of the weight function ϕ (e.g., φ minimizing estimation errors). In order to avoid a subjective choice and naïve selection procedures of φ, the aim of the present paper is to propose an algorithm-based procedure to optimize the DBRFA and automate the choice of ϕ according to objective performance criteria. This procedure is applied to estimate flood quantiles in three different regions in North America. One of the findings from the application is that the optimal weight function depends on the considered region and can also quantify the region's homogeneity. By comparing the DBRFA to the canonical correlation analysis (CCA) method, results show that the DBRFA approach leads to better performances both in terms of relative bias and mean square error.
Energy Technology Data Exchange (ETDEWEB)
Gusev, A A [Institute of Volcanology and Seismology, Russian Academy of Sciences, Petropavlovsk-Kamchatskii (Russian Federation); [Kamchatka Branch, Geophysical Survey, Russian Academy of Sciences, Petropavlovsk-Kamchatskii (Russian Federation)]. E-mail: gusev@emsd.iks.ru; Guseva, E M [Kamchatka Branch, Geophysical Survey, Russian Academy of Sciences, Petropavlovsk-Kamchatskii (Russian Federation); Panza, G F [University of Trieste, Department of Earth Sciences, Trieste (Italy); [Abdus Salam International Centre for Theoretical Physics, SAND Group, Trieste (Italy)
2006-04-15
We recover the gross space-time characteristics of high-frequency (HF) radiator of the great Sumatra-Andaman islands earthquake of Dec. 26, 2004, (M{sub w}=9.0-9.3) using the inversion of parameters describing the time histories of the power of radiated HF P waves. To determine these time histories we process teleseismic P waves at 37 BB stations, using, in sequence: (1) band filtering in the bands 0.4-1.2, 1.2-2, 2-3 and 3-4 Hz; (2) calculation of squared attenuation-corrected acceleration wave amplitudes, making 'power signal'; (3) elimination of distortion related to scattering and expressed as P coda. In step (3) we employ, as an empirical Green function, the power signal determined from an aftershock, from which we construct an inverse filter, and apply it to the recorded power signal. We thus recover the source time function for HF power, with a definite end and no coda. Three parameters are extracted from such signals: full ('100%') duration, temporal centroid, and 99% duration. Through linear inversion, station full durations deliver estimates of the rupture stopping point and stopping time. Similarly, signal temporal centroids and 99% durations can be inverted to obtain the position of the space-time centroid of HF energy radiator and of the point corresponding to the discharge of 99% of the energy. Inversion was successful for the three lower-frequency bands and resulted in the following joint estimates: source length of 1100{+-}220 km (100%) and 800{+-}200 km (99%), source duration of 690 s (100%) and 550 s (99%). The stopping point differs insignificantly from the northern extremity of the aftershock zone. Spatial HF radiation centroid is located at the distance of about 400 km at the azimuth N327W from the epicenter. Rupture propagation velocity estimates are 1.4-1.7 km/s for the entire rupture and 2.3 km/s for its southern, more powerful part. An interesting detail of the source is that the northernmost 300 km of the rupture radiated only 1% of the
International Nuclear Information System (INIS)
Gusev, A.A.; Guseva, E.M.; Panza, G.F.
2006-04-01
We recover the gross space-time characteristics of high-frequency (HF) radiator of the great Sumatra-Andaman islands earthquake of Dec. 26, 2004, (M w =9.0-9.3) using the inversion of parameters describing the time histories of the power of radiated HF P waves. To determine these time histories we process teleseismic P waves at 37 BB stations, using, in sequence: (1) band filtering in the bands 0.4-1.2, 1.2-2, 2-3 and 3-4 Hz; (2) calculation of squared attenuation-corrected acceleration wave amplitudes, making 'power signal'; (3) elimination of distortion related to scattering and expressed as P coda. In step (3) we employ, as an empirical Green function, the power signal determined from an aftershock, from which we construct an inverse filter, and apply it to the recorded power signal. We thus recover the source time function for HF power, with a definite end and no coda. Three parameters are extracted from such signals: full ('100%') duration, temporal centroid, and 99% duration. Through linear inversion, station full durations deliver estimates of the rupture stopping point and stopping time. Similarly, signal temporal centroids and 99% durations can be inverted to obtain the position of the space-time centroid of HF energy radiator and of the point corresponding to the discharge of 99% of the energy. Inversion was successful for the three lower-frequency bands and resulted in the following joint estimates: source length of 1100±220 km (100%) and 800±200 km (99%), source duration of 690 s (100%) and 550 s (99%). The stopping point differs insignificantly from the northern extremity of the aftershock zone. Spatial HF radiation centroid is located at the distance of about 400 km at the azimuth N327W from the epicenter. Rupture propagation velocity estimates are 1.4-1.7 km/s for the entire rupture and 2.3 km/s for its southern, more powerful part. An interesting detail of the source is that the northernmost 300 km of the rupture radiated only 1% of the total HF
Häcker, Axel; Köhrmann, Kai Uwe; Knoll, Thomas; Langbein, Sigrun; Steidler, Annette; Kraut, Oliver; Marlinghaus, Ernst; Alken, Peter; Michel, Maurice Stephan
2004-11-01
The therapeutic application of noninvasive tissue ablation by high-intensity focused ultrasound (HIFU) requires precise physical definition of the focal size and determination of control parameters. The objective of this study was to measure the extent of ex-vivo porcine kidney tissue ablation at variable generator parameters and to identify parameters to control lesion size. The ultrasound waves generated by a cylindrical piezoceramic element (1.04 MHz) were focused at a depth of 100 mm using a parabolic reflector (diameter 100 mm). A needle hydrophone was used to measure the field distribution of the sound pressure. The morphology and extent of tissue necrosis were examined at generator powers of up to 400 W (P(el)) and single pulse durations of as long as 8 seconds. The two-dimensional field distribution resulted in an approximately ellipsoidal focus of 32 x 4 mm (-6 dB). A sharp demarcation between coagulation necrosis and intact tissue was observed. Lesion size was controlled by both the variation of generator power and the pulse duration. At a constant pulse duration of 2 seconds, a generator power of 100 W remained below the threshold doses for inducing a reproducible lesion. An increase in power to as high as 400 W induced lesions with average dimensions of as much as 11.2 x 3 mm. At constant total energy (generator power x pulse duration), lesion size increased at higher generator power. This ultrasound generator can induce defined and reproducible necrosis in ex-vivo kidney tissue. Lesion size can be controlled by adjusting the generator power and pulse duration. Generator power, in particular, turned out to be a suitable control parameter for obtaining a lesion of a defined size.
Delisle, Tony T.; Werch, Chudley E.; Wong, Alvin H.; Bian, Hui; Weiler, Robert
2010-01-01
Background: While studies have determined the importance of physical activity in advancing health outcomes, relatively few have explored the relationship between exercise and various health behaviors of adolescents. The purpose of this study is to examine the relationship between frequency and intensity of physical activity and both health risk…
DEFF Research Database (Denmark)
Madsen, Henrik; Rosbjerg, Dan
1997-01-01
parameters is inferred from regional data using generalized least squares (GLS) regression. Two different Bayesian T-year event estimators are introduced: a linear estimator that requires only some moments of the prior distributions to be specified and a parametric estimator that is based on specified......A regional estimation procedure that combines the index-flood concept with an empirical Bayes method for inferring regional information is introduced. The model is based on the partial duration series approach with generalized Pareto (GP) distributed exceedances. The prior information of the model...
Introduction to Regional Curves including; regressions relating bankfull channelcharacteristics to drainage area, providing estimates of bankfull discharge and channel geometry, validating the selection of the bankfull channel as determined in the field
An Optical Low-frequency Quasi-Periodic Oscillation in the Kepler Light Curve of an Active Galaxy
Mushotzky, Richard; Smith, Krista Lynne; Boyd, Patricia; Wagoner, Robert
2018-01-01
We report the discovery of a candidate quasi-periodic oscillation (QPO) in the optical light curve of KIC 9650712, a Seyfert 1 galaxy in the original Kepler field. After the development and application of a pipeline for Kepler data specific to active galactic nuclei (AGN), one of our sample of 21 AGN selected by infrared photometry and X-ray flux demonstrates a peak in the power spectrum at 10-6.58 Hz, corresponding to a temporal period of 44 days. >From optical spectroscopy, we measure the black hole mass of this AGN as log M = 8.17 M_sun. Despite this high mass, the optical spectrum of KIC 9650712 bears many similarities to Narrow Line Seyfert 1 (NLS1) galaxies, including strong Fe II emission and a low [O III]/Hβ ratio. So far, X-ray QPOs have primarily been seen in NLS1 galaxies. Finally, we find that this frequency lies along a correlation between low-frequency QPOs and black hole mass from stellar and intermediate mass black holes to AGN, similar to the known correlation in high-frequency QPOs.
Hramov, Alexander E.; Sitnikova, Evgenija Y.; Pavlov, Alexey N.; Grubov, Vadim V.; Koronovskii, Alexey A.; Khramova, Marina V.
2015-03-01
Sleep spindles are known to appear spontaneously in the thalamocortical neuronal network of the brain during slow-wave sleep; pathological processes in the thalamocortical network may be the reason of the absence epilepsy. The aim of the present work is to study developed changes in the time-frequency structure of sleep spindles during the progressive development of the absence epilepsy in WAG/Rij rats. EEG recordings were made at age 7 and 9 months. Automatic recognition and subsequent analysis of sleep spindles on the EEG were performed using the continuous wavelet transform. The duration of epileptic discharges and the total duration of epileptic activity were found to increase with age, while the duration of sleep spindles, conversely, decreased. In terms of the mean frequency, sleep spindles could be divided into three classes: `slow' (mean frequency 9.3Hz), `medium' (11.4Hz), and `fast' (13.5Hz). Slow and medium (transitional) spindles in five-month-old animals showed increased frequency from the beginning to the end of the spindle. The more intense the epilepsy is, the shorter are the durations of spindles of all types. The mean frequencies of `medium' and `fast' spindles were higher in rats with more intense signs of epilepsy. Overall, high epileptic activity in WAG/Rij rats was linked with significant changes in spindles of the transitional type, with less marked changes in the two traditionally identified types of spindle, slow and fast.
Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines
Directory of Open Access Journals (Sweden)
P. Guio
Full Text Available In an incoherent scattering radar experiment, the spectral measurement of the so-called up- and downshifted electron plasma lines provides information about their intensity and their Doppler frequency. These two spectral lines correspond, in the backscatter geometry, to two Langmuir waves travelling towards and away from the radar. In the daytime ionosphere, the presence of a small percentage of photoelectrons produced by the solar EUV of the total electron population can excite or damp these Langmuir waves above the thermal equilibrium, resulting in an enhancement of the intensity of the lines above the thermal level. The presence of photo-electrons also modifies the dielectric response function of the plasma from the Maxwellian and thus influences the Doppler frequency of the plasma lines. In this paper, we present a high time-resolution plasma-line data set collected on the Eiscat VHF radar. The analysed data are compared with a model that includes the effect of a suprathermal electron population calculated by a transport code. By comparing the intensity of the analysed plasma lines data to our model, we show that two sharp peaks in the electron suprathermal distribution in the energy range 20-30 eV causes an increased Landau damping around 24.25 eV and 26.25 eV. We have identified these two sharp peaks as the effect of the photoionisation of N2 and O by the intense flux of monochromatic HeII radiation of wavelength 30.378 nm (40.812 eV created in the chromospheric network and coronal holes. Furthermore, we see that what would have been interpreted as a mean Doppler drift velocity for a Maxwellian plasma is actually a shift of the Doppler frequency of the plasma lines due to suprathermal electrons.
Key words. Ionosphere (electric fields and currents; solar radiation and cosmic ray effects
Effect of suprathermal electrons on the intensity and Doppler frequency of electron plasma lines
Directory of Open Access Journals (Sweden)
P. Guio
1999-07-01
Full Text Available In an incoherent scattering radar experiment, the spectral measurement of the so-called up- and downshifted electron plasma lines provides information about their intensity and their Doppler frequency. These two spectral lines correspond, in the backscatter geometry, to two Langmuir waves travelling towards and away from the radar. In the daytime ionosphere, the presence of a small percentage of photoelectrons produced by the solar EUV of the total electron population can excite or damp these Langmuir waves above the thermal equilibrium, resulting in an enhancement of the intensity of the lines above the thermal level. The presence of photo-electrons also modifies the dielectric response function of the plasma from the Maxwellian and thus influences the Doppler frequency of the plasma lines. In this paper, we present a high time-resolution plasma-line data set collected on the Eiscat VHF radar. The analysed data are compared with a model that includes the effect of a suprathermal electron population calculated by a transport code. By comparing the intensity of the analysed plasma lines data to our model, we show that two sharp peaks in the electron suprathermal distribution in the energy range 20-30 eV causes an increased Landau damping around 24.25 eV and 26.25 eV. We have identified these two sharp peaks as the effect of the photoionisation of N2 and O by the intense flux of monochromatic HeII radiation of wavelength 30.378 nm (40.812 eV created in the chromospheric network and coronal holes. Furthermore, we see that what would have been interpreted as a mean Doppler drift velocity for a Maxwellian plasma is actually a shift of the Doppler frequency of the plasma lines due to suprathermal electrons.Key words. Ionosphere (electric fields and currents; solar radiation and cosmic ray effects
Bandrauk, André D.; Mauger, François; Yuan, Kai-Jun
2016-12-01
Numerical solutions of time-dependent Schrödinger equations for one and two electron cyclic molecules {{{H}}}nq+ exposed to intense bichromatic circularly polarized laser pulses of frequencies {ω }1 and {ω }2, such that {ω }1/{ω }2={n}1/{n}2 (integer) produce circularly polarized high order harmonics with a cut-off recollision maximum energy at and greater than the linear polarization law (in atomic units) {N}m{ω }1={I}p+3.17{U}p, where I p is the ionization potential and {U}p={(2{E}0)}2/4{ω }2 is the ponderomotive energy defined by the field E 0 (intensity I={{cE}}02/8π ) from each pulse and mean frequency ω =({ω }1+{ω }2)/2 . An electron recollision model in a rotating frame at rotating frequency {{Δ }}ω =({ω }1-{ω }2)/2 predicts this simple result as a result of recollision dynamics in a combination of bichromatic circularly polarized pulses. The harmonic helicities and their intensities are shown to depend on compatible symmetries of the net pulse electric fields with that of the molecules.
Impact of climate change on flood frequency and intensity in the kabul river basin
Iqbal, Muhammad Shahid; Dahri, Zakir Hussain; Querner, Erik P.; Khan, Asif; Hofstra, Nynke
2018-01-01
Devastating floods adversely affect human life and infrastructure. Various regions of the Hindukush-Karakoram-Himalayas receive intense monsoon rainfall, which, together with snow and glacier melt, produce intense floods. The Kabul river basin originates from the Hindukush Mountains and is
Brooks, Catherine F.; Young, Stacy L.
2016-01-01
This study explored how course instructional format (i.e., online, face-to-face, or hybrid) is related to the frequency and duration of out-of-class communication (OCC) between college instructors and students, to student motives for communicating with teachers, and to perceived teacher approachability for conversation outside of class. Though…
Yang, Y U; Bai, Wenkun; Chen, Yini; Lin, Yanduan; Hu, Bing
2015-11-01
The present study aimed to provide a complete exploration of the effect of sound intensity, frequency, duty cycle, microbubble volume and irradiation time on low-frequency low-intensity ultrasound (US)-mediated microvessel disruption, and to identify an optimal combination of the five factors that maximize the blockage effect. An orthogonal experimental design approach was used. Enhanced US imaging and acoustic quantification were performed to assess tumor blood perfusion. In the confirmatory test, in addition to acoustic quantification, the specimens of the tumor were stained with hematoxylin and eosin and observed using light microscopy. The results revealed that sound intensity, frequency, duty cycle, microbubble volume and irradiation time had a significant effect on the average peak intensity (API). The extent of the impact of the variables on the API was in the following order: Sound intensity; frequency; duty cycle; microbubble volume; and irradiation time. The optimum conditions were found to be as follows: Sound intensity, 1.00 W/cm 2 ; frequency, 20 Hz; duty cycle, 40%; microbubble volume, 0.20 ml; and irradiation time, 3 min. In the confirmatory test, the API was 19.97±2.66 immediately subsequent to treatment, and histological examination revealed signs of tumor blood vessel injury in the optimum parameter combination group. In conclusion, the Taguchi L 18 (3) 6 orthogonal array design was successfully applied for determining the optimal parameter combination of API following treatment. Under the optimum orthogonal design condition, a minimum API of 19.97±2.66 subsequent to low-frequency and low-intensity mediated blood perfusion blockage was obtained.
Causal relations between knowledge-intensive business services and regional employment growth
Brenner, T.; Capasso, M.; Duschl, M.; Frenken, K.; Treibich, T.G.
2015-01-01
This paper studies the causal relations between regional employment growth in Knowledge-Intensive Business Services (KIBS) and overall regional employment growth using German labour-market data for the period 1999-2012. Adopting a recently developed technique, we are able to estimate a structural
Do regional methods really help reduce uncertainties in flood frequency analyses?
Cong Nguyen, Chi; Payrastre, Olivier; Gaume, Eric
2013-04-01
Flood frequency analyses are often based on continuous measured series at gauge sites. However, the length of the available data sets is usually too short to provide reliable estimates of extreme design floods. To reduce the estimation uncertainties, the analyzed data sets have to be extended either in time, making use of historical and paleoflood data, or in space, merging data sets considered as statistically homogeneous to build large regional data samples. Nevertheless, the advantage of the regional analyses, the important increase of the size of the studied data sets, may be counterbalanced by the possible heterogeneities of the merged sets. The application and comparison of four different flood frequency analysis methods to two regions affected by flash floods in the south of France (Ardèche and Var) illustrates how this balance between the number of records and possible heterogeneities plays in real-world applications. The four tested methods are: (1) a local statistical analysis based on the existing series of measured discharges, (2) a local analysis valuating the existing information on historical floods, (3) a standard regional flood frequency analysis based on existing measured series at gauged sites and (4) a modified regional analysis including estimated extreme peak discharges at ungauged sites. Monte Carlo simulations are conducted to simulate a large number of discharge series with characteristics similar to the observed ones (type of statistical distributions, number of sites and records) to evaluate to which extent the results obtained on these case studies can be generalized. These two case studies indicate that even small statistical heterogeneities, which are not detected by the standard homogeneity tests implemented in regional flood frequency studies, may drastically limit the usefulness of such approaches. On the other hand, these result show that the valuation of information on extreme events, either historical flood events at gauged
International Nuclear Information System (INIS)
Graziani, G.; Maineri, M.; Zanantoni, C.
1976-12-01
The role of the load-duration curve in determining the installation policy for an electric power system, is examined. The effect of the priority order for the allocation of the power stations in the load-diagram is also discussed: in the model used here (program TOTEM) this priority is given as a function of type and age of the station. The significance of the load factor history for a power station as a function of its age is also discussed. It is suggested that such a curve be deduced as a result of strategy calculations made with TOTEM rather than assumping it as input data
Optimal depth-based regional frequency analysis
Directory of Open Access Journals (Sweden)
H. Wazneh
2013-06-01
Full Text Available Classical methods of regional frequency analysis (RFA of hydrological variables face two drawbacks: (1 the restriction to a particular region which can lead to a loss of some information and (2 the definition of a region that generates a border effect. To reduce the impact of these drawbacks on regional modeling performance, an iterative method was proposed recently, based on the statistical notion of the depth function and a weight function φ. This depth-based RFA (DBRFA approach was shown to be superior to traditional approaches in terms of flexibility, generality and performance. The main difficulty of the DBRFA approach is the optimal choice of the weight function ϕ (e.g., φ minimizing estimation errors. In order to avoid a subjective choice and naïve selection procedures of φ, the aim of the present paper is to propose an algorithm-based procedure to optimize the DBRFA and automate the choice of ϕ according to objective performance criteria. This procedure is applied to estimate flood quantiles in three different regions in North America. One of the findings from the application is that the optimal weight function depends on the considered region and can also quantify the region's homogeneity. By comparing the DBRFA to the canonical correlation analysis (CCA method, results show that the DBRFA approach leads to better performances both in terms of relative bias and mean square error.
Directory of Open Access Journals (Sweden)
Fazlul Karim
2017-06-01
Full Text Available Understanding the nature of frequent floods is important for characterising channel morphology, riparian and aquatic habitat, and informing river restoration efforts. This paper presents results from an analysis on frequency estimates of low magnitude floods using the annual maximum and partial series data compared to actual flood series. Five frequency distribution models were fitted to data from 24 gauging stations in the Great Barrier Reef (GBR lagoon catchments in north-eastern Australia. Based on the goodness of fit test, Generalised Extreme Value, Generalised Pareto and Log Pearson Type 3 models were used to estimate flood frequencies across the study region. Results suggest frequency estimates based on a partial series are better, compared to an annual series, for small to medium floods, while both methods produce similar results for large floods. Although both methods converge at a higher recurrence interval, the convergence recurrence interval varies between catchments. Results also suggest frequency estimates vary slightly between two or more partial series, depending on flood threshold, and the differences are large for the catchments that experience less frequent floods. While a partial series produces better frequency estimates, it can underestimate or overestimate the frequency if the flood threshold differs largely compared to bankfull discharge. These results have significant implications in calculating the dependency of floodplain ecosystems on the frequency of flooding and their subsequent management.
White, Victoria M; Durkin, Sarah J; Coomber, Kerri; Wakefield, Melanie A
2015-03-01
To examine how the intensity and duration of tobacco control advertising relate to adolescent smoking prevalence. Australian students (aged 12-17 years) participating in a national survey conducted triennially between 1993 and 2008 (sample size range 12 314-16 611). The outcome measure was students' smoking in the previous 4 weeks collected through anonymous, self-completed surveys. For each student, monthly targeted rating points (TRPs, a measure of television advertising exposure) for tobacco control advertising was calculated for the 3 and 12 months prior to surveying. For each time period, cumulative TRPs exposure and exposure to three intensity levels (≥100 TRPs/month; ≥400 TRPs/month; ≥800 TRPs/month) over increasing durations (eg, 1 month, 2 months, etc) were calculated. Logistic regression examined associations between TRPs and adolescent smoking after controlling for demographic and policy variables. Past 3-month cumulative TRPs were found to have an inverse relationship with smoking prevalence. Low TRPs exposure in the past 12 months was positively associated with adolescent smoking prevalence. However, smoking prevalence reduced with cumulative exposure levels above 5800 cumulative TRPs. Additionally, exposure to ≥400 TRPs/month and ≥800 TRPs/month were associated with reduced likelihood of smoking, although the duration needed for this effect differed for the two intensity levels. When intensity was ≥400 TRPs/month, the odds of smoking only reduced with continuous exposure. When intensity was ≥800 TRPs/month, exposure at levels less than monthly was associated with reductions in smoking prevalence. Both antismoking advertising intensity and duration are important for ensuring reductions in adolescent smoking prevalence. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
International Nuclear Information System (INIS)
Ilyinskikh, N.N.; Ilyinskikh, E.N.; Yurkin, A.Yu.; Ilyinskikh, I.N.
2003-01-01
We have assessed frequencies of micro-nucleated lymphocytes in 3036 individuals living in 16 settlements in the west of the Altay region. Among the settlements the majority of individuals with significantly high frequencies of micro-nucleated lymphocytes were detected in settlements adjacent to the Semipalatinsk atomic testing ground (SATG). The most considerable genome instability was found in the individuals born in the period of intensive testing on the SATG (from 1949 to 1962). Moreover, we have determined that the residents of the settlements adjacent to the SATG have significantly high levels of antibodies to potentially oncogenic Epstein-Barr virus besides high frequencies of micro-nucleated lymphocytes. The considerable Epstein-Barr virus contamination among the residents in the radiation polluted zone around the SATG was supposed to be caused by immunodeficiency disorders in these individuals and induce high frequencies of micro-nucleated cells. (author)
Intense high-frequency gyrotron-based microwave beams for material processing
Energy Technology Data Exchange (ETDEWEB)
Hardek, T.W.; Cooke, W.D.; Katz, J.D.; Perry, W.L.; Rees, D.E.
1997-03-01
Microwave processing of materials has traditionally utilized frequencies in the 0.915 and 2.45 GHz regions. Microwave power sources are readily available at these frequencies but the relatively long wavelengths can present challenges in uniformly heating materials. An additional difficulty is the poor coupling of ceramic based materials to the microwave energy. Los Alamos National Laboratory scientists, working in conjunction with the National Center for Manufacturing Sciences (NCMS), have assembled a high-frequency demonstration processing facility utilizing gyrotron based RF sources. The facility is primarily intended to demonstrate the unique features available at frequencies as high as 84 GHz. The authors can readily provide quasi-optical, 37 GHz beams at continuous wave (CW) power levels in the 10 kW range. They have also provided beams at 84 GHz at 10 kW CW power levels. They are presently preparing a facility to demonstrate the sintering of ceramics at 30 GHz. This paper presents an overview of the present demonstration processing facility and describes some of the features they have available now and will have available in the near future.
Intense rainfalls prediction models for the state of Mato Grosso, Brazil
Directory of Open Access Journals (Sweden)
Sidney Pereira
2011-12-01
Full Text Available Rain intensity data are necessary to increase security of hydraulic projects. The objective of this study was to determine the relationships among intensity-duration-frequency (IDF and Bell’s model for the State of Mato Grosso, Brazil. The equations were obtained by disaggregation of 24 h rainfall data from 136 rain stations available in the National Water Agency (ANA data base. Employing Gumbel distribution, the rainfalls were estimated for each time duration and for the return periods of 2, 5, 10, 25, 50 and 100 years, and thereafter for each season. The coefficients of IDF relationships and Bell’s models were adjusted by the minimum square method, for all seasons evaluated. The coefficients of determination and Willmott agreement index exceeded 0.98 and 0.85, respectively, for all stations, which classifies the adjustment of the rainfall models as great.
Müller, Eva; Pfister, Angela; Gerd, Büger; Maik, Heistermann; Bronstert, Axel
2015-04-01
Hydrological extreme events can be triggered by rainfall on different spatiotemporal scales: river floods are typically caused by event durations of between hours and days, while urban flash floods as well as soil erosion or contaminant transport rather result from storms events of very short duration (minutes). Still, the analysis of climate change impacts on rainfall-induced extreme events is usually carried out using daily precipitation data at best. Trend analyses of extreme rainfall at sub-daily or even sub-hourly time scales are rare. In this contribution two lines of research are combined: first, we analyse sub-hourly rainfall data for several decades in three European regions.Second, we investigate the scaling behaviour of heavy short-term precipitation with temperature, i.e. the dependence of high intensity rainfall on the atmospheric temperature at that particular time and location. The trend analysis of high-resolution rainfall data shows for the first time that the frequency of short and intensive storm events in the temperate lowland regions in Germany has increased by up to 0.5 events per year over the last decades. I.e. this trend suggests that the occurrence of these types of storms have multiplied over only a few decades. Parallel to the changes in the rainfall regime, increases in the annual and seasonal average temperature and changes in the occurrence of circulation patterns responsible for the generation of high-intensity storms have been found. The analysis of temporally highly resolved rainfall records from three European regions further indicates that extreme precipitation events are more intense with warmer temperatures during the rainfall event. These observations follow partly the Clausius-Clapeyron relation. Based on this relation one may derive a general rule of maximum rainfall intensity associated to the event temperature, roughly following the Clausius-Clapeyron (CC) relation. This rule might be used for scenarios of future maximum
Sarikabadayi, Yusuf Unal; Aydemir, Ozge; Ozen, Zuhal Tunay; Aydemir, Cumhur; Tok, Levent; Oguz, Serife Suna; Erdeve, Omer; Uras, Nurdan; Dilmen, Ugur
2011-12-01
We aimed to determine applicable guidelines for screening of retinopathy of prematurity (ROP), and evaluate the contribution of risk factors for severe ROP. A prospective cohort study of neonates with a gestational age (GA) < 34 weeks or birth weight < 2000g who were admitted to the Neonatal Intensive Care Unit (NICU) of a tertiary level hospital was conducted. The study group was classified into three groups according to eye examination findings as no ROP, mild ROP and severe ROP. Of the 700 neonates screened, the frequencies of ROP for any stage and severe ROP were 32.7% and 3.1%, respectively. Laser photocoagulation was needed in 9.6% of neonates with ROP. None of the neonates with a GA ≥ 31 weeks required treatment. Any ROP was detected in 199 (53.6%) of the babies < 32 weeks (n = 371), 22 (5.9%) of whom were treated with laser photocoagulation. Independent risk factors for severe ROP in babies < 32 weeks GA were birth weight, duration of mechanical ventilation and patent ductus arteriosus (PDA). This is the largest prospective cohort study including infants younger than 34 weeks GA from Turkey. Our data which belongs to the last 1-year period shows lower incidence of severe ROP when compared to previous reports from Turkey. According to our data, screening babies smaller than 32 weeks GA or 1500g birth weight seems reasonable. In the presence of long duration of mechanical ventilation and PDA, screening should be intensified.
Prediction of a photovoltaic system performance using cumulative frequency curves of radiation
Energy Technology Data Exchange (ETDEWEB)
Lasnier, F; Sivoththaman, S [Asian Inst. of Technology, Bangkok (TH). Div. of Energy Technology
1990-01-01
The system performance of stand-alone photovoltaic systems is analysed. From the hourly radiation data for Bangkok (from 1984 to 1987) the cumulative frequency curves of radiation are generated and a typical meteorological day (TMD) is created each year. The system performance is determined using both the TMD radiation and the actual radiation values. The comparison results show that the TMD method can be applied for the sizing of stand-alone photovoltaic systems. The storage batteries of realistic sizes usually exhibit a daily cyclic variation in state-of-charge, with constant load consumption. Only very large and unrealistic sizes of batteries show a seasonal variation in state-of-charge. This is the fact that prompted the attempt to predict the system performance for a season by using a single representative day (TMD) of that season. Apart from giving reliable results, the TMD method significantly reduces the computation time and simplifies the process. (author).
Electro-Mechanical Resonance Curves
Greenslade, Thomas B., Jr.
2018-01-01
Recently I have been investigating the frequency response of galvanometers. These are direct-current devices used to measure small currents. By using a low-frequency function generator to supply the alternating-current signal and a stopwatch smartphone app to measure the period, I was able to take data to allow a resonance curve to be drawn. This…
David, Marianne; Dinse, Hubert R; Mainka, Tina; Tegenthoff, Martin; Maier, Christoph
2015-01-01
Achieving perceptual gains in healthy individuals or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS). For example, high-frequency repetitive sensory stimulation (HF-rSS) enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS) show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS) to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high- or low-frequency electrical stimuli were applied for 45 min/day to all fingertips of the affected hand for 5 days. Main outcome measures were spatial two-point-discrimination thresholds and mechanical detection thresholds measured on the tip of the index finger bilaterally. Secondary endpoint was current pain intensity. All measures were assessed before and on day 5 after the last stimulation session. HF-rSS applied in 16 patients improved tactile discrimination on the affected hand significantly without changes contralaterally. Current pain intensity remained unchanged on average, but decreased in four patients by ≥30%. This limited pain relief might be due to the short stimulation period of 5 days only. In contrast, after LF-rSS, tactile discrimination was impaired in all four patients, while detection thresholds and pain were not affected. Our data suggest that HF-rSS could be used as a novel approach in CRPS treatment to improve sensory loss. Longer treatment periods might be required to induce consistent pain relief.
Kornhuber, Kai; Rybski, Diego; Costa, Luis; Reusser, Dominik E.; Kropp, Jürgen P.
2014-05-01
The Environmental Kuznets Curves (EKC) postulates that pollution increases with the income per capita up to a maximum, above which it decreases with the further increase in income per capita, i.e. following an inverse U-shape in the pollution vs. income per capita. It is commonly believed that EKC occurs for "local" pollutants such as nitrogen oxide and sulfur dioxide, but does not hold for CO2 emissions. This is attributed to the fact that while "local" pollutants cause a visible environmental damage on the local/regional scale (which authorities/governments seek to avoid), the consequences of CO2 emission have no immediate attributable local/regional consequences. We review EKC for CO2 exploring its relation between CO2 per capita and the Human Development Index (HDI) between 1990 and 2010 obtained from the World Bank database. We find evidence for a reduction in CO2 emissions per capita in highly developed countries. We propose a model according to which the emissions per capita of a country are composed of a component related to the actual state of development and a component related to the change of development. The model leads to four distinct cases of which two have EKC shape and two imply saturation. This outcome is in line with previously suggested qualitative relations. Our analysis indicates that the EKC shaped cases better describes the empirical values. We explore the less extreme version corresponding to the so-called conventional EKC and study the maximum of the fitted curve, providing a threshold-value for the HDI and a typical maximum value for the emissions per capita. We find that approx. 5 countries have crossed the CO2-HDI maximum, corresponding to approx. 1.5% of the world population.
Estimation of Typhoon Wind Hazard Curves for Nuclear Sites
Energy Technology Data Exchange (ETDEWEB)
Choun, Young-Sun; Kim, Min-Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2016-10-15
The intensity of such typhoons, which can influence the Korean Peninsula, is on an increasing trend owing to a rapid change of climate of the Northwest Pacific Ocean. Therefore, nuclear facilities should be prepared against future super-typhoons. Currently, the U.S. Nuclear Regulatory Commission requires that a new NPP should be designed to endure the design-basis hurricane wind speeds corresponding to an annual exceedance frequency of 10{sup -7} (return period of 10 million years). A typical technique used to estimate typhoon wind speeds is based on a sampling of the key parameters of typhoon wind models from the distribution functions fitting statistical distributions to the observation data. Thus, the estimated wind speeds for long return periods include an unavoidable uncertainty owing to a limited observation. This study estimates the typhoon wind speeds for nuclear sites using a Monte Carlo simulation, and derives wind hazard curves using a logic-tree framework to reduce the epistemic uncertainty. Typhoon wind speeds were estimated for different return periods through a Monte-Carlo simulation using the typhoon observation data, and the wind hazard curves were derived using a logic-tree framework for three nuclear sites. The hazard curves for the simulated and probable maximum winds were obtained. The mean hazard curves for the simulated and probable maximum winds can be used for the design and risk assessment of an NPP.
International Nuclear Information System (INIS)
Zhuang Hua; Yang Zhigang; Wang Ziqiang; Wang Xiaodong; Chen Huijiao; Zhang Yuanchuan; Luo Yan
2012-01-01
Purpose: This study is to investigate the value of double contrast-enhanced ultrasonography (DCEU) in assessing microcirculation of colorectal adenocarcinomas and to describe the perfusion features of the tumours. Material and methods: DCEUS was performed in 42 patients with adenocarcinoma. The time–intensity curve parameters (arrival time (AT), time-to-peak (TTP), peak intensity (PI) and area under the curve (AUC)) within the tumours were extracted. The parameters were compared among the tumours with different CEUS features and stages. Results: The mean values of AT, TTP, PI and AUC of the colorectal adenocarcinomas were 13.68 ± 13.36 s, 32.61 ± 19.56 s, 19.82 ± 16.54 dB and 271.10 ± 159.19 dB s, respectively. In the adenocarcinomas with necrosis, the mean values of AUC was significantly lower than that of the adenocarcinomas without (231.10 ± 219.27 dB s, 278.10 ± 123.20 dB s, p = 0.004). In the adenocarcinomas with necrosis, the AUC and PI of the non-necrotic part were significantly higher than that of the necrotic part (p = 0.007, 0.0025, respectively). AUC increased progressively in the subgroups of T2, T3 and T4 and the difference of AUC between T2 and T4 subgroup was significant (p = 0.008). Conclusions: Double contrast-enhanced ultrasonography is a valuable technique for quantifying tumour vascularity of colorectal adenocarcinomas. AUC was significantly different in the subgroups of different T stage. AUC and PI could reflect the different perfusion status of tumours with or without necrosis.
Setiono, Andi; Ula, Rini Khamimatul; Hanto, Dwi; Widiyatmoko, Bambang; Purnamaningsih, Retno Wigajatri
2016-02-01
In general, Fiber Bragg Grating (FBG) sensor works based on observation of spectral response characteristic to detect the desired parameter. In this research, we studied intensity response characteristic of FBG to detect the dynamic strain. Experiment result show that the reflected intensity had linier relationships with dynamic strain. Based on these characteristics, we developed the FBG sensor to detect low frequency vibration. This sensor is designed by attaching the FBG on the bronze cantilever with dimensions of 85×3×0.5 mm. Measurement results showed that the sensor was able to detect vibrations in the frequency range of 7-10 Hz at temperature range of 25-45 ˚C. The measured frequency range is still within the frequency range of digging activity, therefore this vibration sensor can be applied for oil pipelines vandalisation detection system.
Localizing New Pulsars with Intensity Mapping
Swiggum, Joe; Gentile, Peter
2018-01-01
Although low-frequency, single dish pulsar surveys provide an efficient means of searching large regions of sky quickly, the localization of new discoveries is poor. For example, discoveries from 350 MHz surveys using the Green Bank Telescope (GBT) have position uncertainties up to the FWHM of the telescope's "beam" on the sky, over half a degree! Before finding a coherent timing solution (requires 8-12 months of dedicated timing observations) a "gridding" method is usually employed to improve localization of new pulsars, whereby a grid of higher frequency beam positions is used to tile the initial error region. This method often requires over an hour of observing time to achieve arcminute-precision localization (provided the pulsar is detectable at higher frequencies).Here, we describe another method that uses the same observing frequency as the discovery observation and scans over Right Ascension and Declination directions around the nominal position. A Gaussian beam model is fit to folded pulse profile intensities as a function of time/position to provide improved localization. Using five test cases, we show that intensity mapping localization at 350 MHz with the GBT yields pulsar positions to 1 arcminute precision, facilitating high-frequency follow-up and higher significance detections for future pulsar timing. This method is also well suited to be directly implemented in future low-frequency drift scan pulsar surveys (e.g. with the Five hundred meter Aperture Spherical Telescope; FAST).
Hindle, Alyssa R; Lou, Jenny W H; Collins, David F
2014-10-01
The afferent volley generated by neuromuscular electrical stimulation (NMES) influences corticospinal (CS) excitability and frequent NMES sessions can strengthen CS pathways, resulting in long-term improvements in function. This afferent volley can be altered by manipulating NMES parameters. Presently, we manipulated one such parameter, pulse duration, during NMES over the common peroneal nerve and assessed the influence on H-reflexes and CS excitability. We hypothesized that compared with shorter pulse durations, longer pulses would (i) shift the H-reflex recruitment curve to the left, relative to the M-wave curve; and (ii) increase CS excitability more. Using 3 pulse durations (50, 200, 1000 μs), M-wave and H-reflex recruitment curves were collected and, in separate experiments, CS excitability was assessed by comparing motor evoked potentials elicited before and after 30 min of NMES. Despite finding a leftward shift in the H-reflex recruitment curve when using the 1000 μs pulse duration, consistent with a larger afferent volley for a given efferent volley, the increases in CS excitability were not influenced by pulse duration. Hence, although manipulating pulse duration can alter the relative recruitment of afferents and efferents in the common peroneal nerve, under the present experimental conditions it is ineffective for maximizing CS excitability for rehabilitation.
Sadala, Adria Y; Machado, Aline F P; Liebano, Richard E
2018-01-16
Carboxytherapy may generate local pain that is considered the main limiting factor in clinical practice. Transcutaneous electric nerve stimulation (TENS) is widely used in the control of acute pain; however, the effect of TENS on pain relief during carboxytherapy has not been studied to date. To assess the effect of TENS on pain intensity during carboxytherapy in patients with cellulite in the gluteal region. This randomized clinical trial was conducted with 84 patients, 18-44 years of age, who had moderate cellulite in the gluteal region, according to Cellulite Severity Scale, but never received carboxytherapy. Patients were randomized into 3 groups: active TENS, placebo TENS, and control group. For the intervention, skin depressions with cellulite were outlined, and the gluteal area to be treated was defined. The subcutaneous injection of CO 2 was performed using 0.30 × 13 mm-needles at a 45° angle, with a controlled flow rate of 100 mL/min maintained for 1 minute at each puncture site. The parameters for TENS were as follows: frequency of 100 Hz and pulse duration of 200 μs; TENS intensity was adjusted until the patient reported strong paresthesia. The visual numeric pain rating scale was used to assess pain intensity after each puncture. The active TENS group reported lower pain intensity compared to the placebo TENS (P TENS) was effective in reducing pain intensity during carboxytherapy in patients with cellulite in the gluteal region. © 2018 Wiley Periodicals, Inc.
Bubble dynamics under acoustic excitation with multiple frequencies
International Nuclear Information System (INIS)
Zhang, Y N; Zhang, Y N; Li, S C
2015-01-01
Because of its magnificent mechanical and chemical effects, acoustic cavitation plays an important role in a broad range of biomedical, chemical and mechanical engineering problems. Particularly, irradiation of the multiple frequency acoustic wave could enhance the effects of cavitation. The advantages of employment of multi-frequency ultrasonic field include decreasing the cavitation thresholds, promoting cavitation nuclei generation, increasing the mass transfer and improving energy efficiency. Therefore, multi-frequency ultrasonic systems are employed in a variety of applications, e.g., to enhance the intensity of sonoluminenscence, to increase efficiency of sonochemical reaction, to improve the accuracy of ultrasound imaging and the efficiency of tissue ablation. Compared to single-frequency systems, a lot of new features of bubble dynamics exist in multi-frequency systems, such as special properties of oscillating bubbles, unique resonances in the bubble response curves, and unusual chaotic behaviours. In present paper, the underlying mechanisms of the cavitation effects under multi-frequency acoustical excitation are also briefly introduced
International Nuclear Information System (INIS)
Hajra, Rajkumar; Echer, Ezequiel; Gonzalez, Walter D.; Tsurutani, Bruce T.; Santolik, Ondrej
2015-01-01
Radiation-belt relativistic (E > 0.6, > 2.0, and > 4.0 MeV) electron acceleration is studied for solar cycle 23 (1995-2008). High-intensity, long-duration, continuous AE activity (HILDCAA) events are considered as the basis of the analyses. All of the 35 HILDCAA events under study were found to be characterized by flux enhancements of magnetospheric relativistic electrons of all three energies compared to the pre-event flux levels. For the E > 2.0 MeV electron fluxes, enhancement of >50% occurred during 100% of HILDCAAs. Cluster-4 passes were examined for electromagnetic chorus waves in the 5 < L < 10 and 0 < MLT < 12 region when wave data were available. Fully 100% of these HILDCAA cases were associated with enhanced whistler-mode chorus waves. The enhancements of E > 0.6, > 2.0, and > 4.0 MeV electrons occurred ∼1.0 day, ∼1.5 days, and ∼2.5 days after the statistical HILDCAA onset, respectively. The statistical acceleration rates for the three energy ranges were ∼1.8 × 10 5 , 2.2 × 10 3 , and 1.0 × 10 1 cm –2 s –1 sr –1 d –1 , respectively. The relativistic electron-decay timescales were determined to be ∼7.7, 5.5, and 4.0 days for the three energy ranges, respectively. The HILDCAAs were divided into short-duration (D ≤ 3 days) and long-duration (D > 3 days) events to study the dependence of relativistic electron variation on HILDCAA duration. For long-duration events, the flux enhancements during HILDCAAs with respect to pre-event fluxes were ∼290%, 520%, and 82% for E > 0.6, > 2.0, and > 4.0 MeV electrons, respectively. The enhancements were ∼250%, 400%, and 27% respectively, for short-duration events. The results are discussed with respect to the current understanding of radiation-belt dynamics
Frequency of central nervous system tumors in delta region, Egypt
Directory of Open Access Journals (Sweden)
Khaled R Zalata
2011-01-01
Full Text Available Introduction and Aim of Work: Central nervous system (CNS tumors represent a major public health problem, and their epidemiological data in Egypt have been rather incomplete except for some regional reports. There are no available frequency-based data on CNS tumors in our locality. The objective of this study was to estimate the frequency of CNS tumors in east delta region, Egypt. Materials and Methods: The data were collected during the 8-year period from January 1999 to December 2007 from Pathology Department, Mansoura University, and other referred pathology labs. Examination of HandE stained sections from retrieved paraffin blocks were done in all cases for histopathologic categorization of C.N.S. tumors. Immunohistochemical studies were applied to confirm final histopathologic diagnosis in problematic cases. Results: Intracranial tumors represented 86.7% of cases in comparison to only 13.3% for spinal tumors. Gliomas were the CNS tumors of the highest frequency (35.2%, followed by meningioma (25.6%, pituitary adenoma (11.6% and nerve sheath tumors (6.6%. 10.25% of tumors were of children <15 years. Conclusion: This study provides the largest series of the relative frequency of CNS tumors in Delta region in Egypt till now and may help to give insight into the epidemiology of CNS tumors in our locality.
Withagen, C.A.A.M.; de Groot, H.L.F.; Minliang, Z.
2004-01-01
This paper addresses the existence of an Environmental Kuznets Curve for China, using a sample of 30 regions, covering the period 1982-1997. The types of pollution included are wastewater, waste gas, and solid waste. We consider the development of the sources of pollution in a pooled cross-section
New fat suppression RF pulse with shorter duration
International Nuclear Information System (INIS)
Yamaguchi, Kojiro; Ukai, Hiroyuki
2010-01-01
The fat suppression radio frequency pulse currently employed for MRI, which selectively saturates the frequency of the fat, has the narrow-band frequency characteristics. Therefore, the application duration for the pulse employed tends to be prolonged. In the present study, we designed a new fat suppression radiofrequency (RF) pulse using the Laguerre function in order to shorten the duration for fat suppression RF pulse and conducted an evaluation with the clinical equipment. The length of the RF pulse that we created allowed to reduce the duration by 47.3% compared with that employed for the clinical equipment. In addition, in the MR imaging evaluation, the new pulse was confirmed to have the fat suppression effect equivalent to that employed for the clinical equipment. (author)
Deriving Area-storage Curves of Global Reservoirs
Mu, M.; Tang, Q.
2017-12-01
Basic information including capacity, dam height, and largest water area on global reservoirs and dams is well documented in databases such as GRanD (Global Reservoirs and Dams), ICOLD (International Commission on Large Dams). However, though playing a critical role in estimating reservoir storage variations from remote sensing or hydrological models, area-storage (or elevation-storage) curves of reservoirs are not publicly shared. In this paper, we combine Landsat surface water extent, 1 arc-minute global relief model (ETOPO1) and GRanD database to derive area-storage curves of global reservoirs whose area is larger than 1 km2 (6,000 more reservoirs are included). First, the coverage polygon of each reservoir in GRanD is extended to where water was detected by Landsat during 1985-2015. Second, elevation of each pixel in the reservoir is extracted from resampled 30-meter ETOPO1, and then relative depth and frequency of each depth value is calculated. Third, cumulative storage is calculated with increasing water area by every one percent of reservoir coverage area and then the uncalibrated area-storage curve is obtained. Finally, the area-storage curve is linearly calibrated by the ratio of calculated capacity over reported capacity in GRanD. The derived curves are compared with in-situ reservoir data collected in Great Plains Region in US, and the results show that in-situ records are well captured by the derived curves even in relative small reservoirs (several square kilometers). The new derived area-storage curves have the potential to be employed in global monitoring or modelling of reservoirs storage and area variations.
Effect of sound intensity on tonotopic fMRI maps in the unanesthetized monkey.
Tanji, Kazuyo; Leopold, David A; Ye, Frank Q; Zhu, Charles; Malloy, Megan; Saunders, Richard C; Mishkin, Mortimer
2010-01-01
The monkey's auditory cortex includes a core region on the supratemporal plane (STP) made up of the tonotopically organized areas A1, R, and RT, together with a surrounding belt and a lateral parabelt region. The functional studies that yielded the tonotopic maps and corroborated the anatomical division into core, belt, and parabelt typically used low-amplitude pure tones that were often restricted to threshold-level intensities. Here we used functional magnetic resonance imaging in awake rhesus monkeys to determine whether, and if so how, the tonotopic maps and the pattern of activation in core, belt, and parabelt are affected by systematic changes in sound intensity. Blood oxygenation level-dependent (BOLD) responses to groups of low- and high-frequency pure tones 3-4 octaves apart were measured at multiple sound intensity levels. The results revealed tonotopic maps in the auditory core that reversed at the putative areal boundaries between A1 and R and between R and RT. Although these reversals of the tonotopic representations were present at all intensity levels, the lateral spread of activation depended on sound amplitude, with increasing recruitment of the adjacent belt areas as the intensities increased. Tonotopic organization along the STP was also evident in frequency-specific deactivation (i.e. "negative BOLD"), an effect that was intensity-specific as well. Regions of positive and negative BOLD were spatially interleaved, possibly reflecting lateral inhibition of high-frequency areas during activation of adjacent low-frequency areas, and vice versa. These results, which demonstrate the strong influence of tonal amplitude on activation levels, identify sound intensity as an important adjunct parameter for mapping the functional architecture of auditory cortex.
TORREFACTION OF CELLULOSE: VALIDITY AND LIMITATION OF THE TEMPERATURE/DURATION EQUIVALENCE
Directory of Open Access Journals (Sweden)
Pin Lv,
2012-06-01
Full Text Available During torrefaction of biomass, equivalence between temperature and residence time is often reported, either in terms of the loss of mass or the alternation of properties. The present work proposes a rigorous investigation of this equivalence. Cellulose, as the main lignocellulosic biomass component, was treated under mild pyrolysis for 48 hours. Several couples of T-D (temperature-duration points were selected from TGA curves to obtain mass losses of 11.6%, 25%, 50%, 74.4%, and 86.7%. The corresponding residues were subjected to Fourier transform infrared spectroscopy for analysis. According to the FTIR results, a suitably accurate match to global T-D equivalence is exhibited up to 50% mass loss: in this domain, mass loss is well correlated to the treatment intensity (molecular composition of the residue except for slight differences in the production of C=C and C=O. For mass loss levels of 74.4% and 86.7%, distinct degradation mechanisms take place at different combinations of temperature and duration, and the correlation fails. Compared to the mass loss at 220°C and 250°C, the equivalent molecular composition can be achieved through treatment at 280°C with shorter treatment time and less depolymerization and oxidation. The main conclusion drawn is that mass loss can be used as a synthetic indicator of the treatment intensity in the temperature range of 220°C to 280°C up to a mass loss of 50%.
Yan, D. H.; Wu, D.; Huang, R.; Wang, L. N.; Yang, G. Y.
2013-03-01
According to the Chinese climate divisions and the Huang-Huai-Hai River basin digital elevation map, the basin is divided into seven sub-regions by means of cluster analysis of the basin meteorological stations using the self-organizing map (SOM) neural network method. Based on the daily precipitation data of 171 stations for the years 1961-2011, the drought frequency changes with different magnitudes are analyzed and the number of consecutive days without precipitation is used to identify the drought magnitudes. The first precipitation intensity after a drought period is analyzed with the Pearson-III frequency curve, then the relationship between rainfall intensity and different drought magnitudes is observed, as are the drought frequency changes for different years. The results of the study indicated the following: (1) the occurrence frequency of different drought level shows an overall increasing trend; there is no clear interdecadal change shown, but the spatial difference is significant. The occurrence frequencies of severe and extraordinary drought are higher on the North China Plain, Hetao Plains in Ningxia-Inner Mongolia, as well as on the Inner Mongolia and the Loess Plateaus, and in the Fen-Wei Valley basin. (2) As the drought level increases, the probability of extraordinary rainstorm becomes lower, and the frequency of occurrence of spatial changes in different precipitation intensities vary. In the areas surrounding Bo Sea, the Shandong Peninsula and the Huai River downstream, as the drought level increases, the occurrence frequency of different precipitation intensities first shows a decreasing trend, which becomes an increasing trend when extraordinary drought occurs. In the middle and upper reaches of the Huai River basin, on the Hai River basin piedmont plain and Hetao Plains in Ningxia-Inner Mongolia, Inner Mongolia and Loess Plateaus, and in the Fen-Wei Valley basin, the probability of the different precipitation intensities shows an overall
Regional Marginal Abatement Cost Curves for NOx
U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...
Miller, A. D.
2015-12-01
Many aspects of disturbance processes can have large impacts on the composition of plant communities, and associated changes in land cover type in turn have biogeochemical feedbacks to climate. In particular, changes to disturbance regimes can potentially change the number and stability of equilibrial states, and plant community states can differ dramatically in their carbon (C) dynamics, energy balance, and hydrology. Using the Klamath region of northern California as a model system, we present a theoretical analysis of how changes to climate and associated fire dynamics can disrupt high-carbon, long-lived conifer forests and replace them with shrub-chaparral communities that have much lower biomass and are more pyrogenic. Specifically, we develop a tractable model of plant community dynamics, structured by size class, life-history traits, lottery-type competition, and species-specific responses to disturbance. We assess the stability of different states in terms of disturbance frequency and intensity, and quantitatively partition long-term low-density population growth rates into mechanisms that influence critical transitions from stable to bistable behavior. Our findings show how different aspects of disturbance act and interact to control competitive outcomes and stable states, hence ecosystem-atmosphere C exchange. Forests tend to dominate in low frequency and intensity regimes, while shrubs dominate at high fire frequency and intensity. In other regimes, the system is bistable, and the fate of the system depends both on initial conditions and random chance. Importantly, the system can cross a critical threshold where hysteresis prevents easy return to the prior forested state. We conclude that changes in disturbance-recovery dynamics driven by projected climate change can shift this system away from forest dominated in the direction of shrub-dominated landscape. This will result in a large net C release from the landscape, and alter biophysical ecosystem
Penumetcha, Neeraja; Kabadi, Suraj; Jedynak, Bruno; Walcutt, Charles; Gado, Mokhtar H; Wang, Lei; Ratnanather, J Tilak
2011-04-01
This paper describes a feasibility study of a method for delineating the tentorium cerebelli in magnetic resonance imaging (MRI) brain scans. The tentorium cerebelli is a thin sheet of dura matter covering the cerebellum and separating it from the posterior part of the temporal lobe and the occipital lobe of the cerebral hemispheres. Cortical structures such as the parahippocampal gyrus can be indistinguishable from tentorium in magnetized prepared rapid gradient echo and T1-weighted MRI scans. Similar intensities in these neighboring regions make it difficult to perform accurate cortical analysis in neuroimaging studies of schizophrenia and Alzheimer's disease. A semi-automated, geometric, intensity-based procedure for delineating the tentorium from a whole-brain scan is described. Initial and final curves are traced within the tentorium. A cost function, based on intensity and Euclidean distance, is computed between the two curves using the Fast Marching method. The initial curve is then evolved to the final curve based on the gradient of the computed costs, generating a series of intermediate curves. These curves are then used to generate a triangulated surface of the tentorium. For 3 scans, surfaces were found to be within 2 voxels from hand segmentations. Copyright © 2009 by the American Society of Neuroimaging.
Suriyapee, S; Pitaxtarnin, N; Oonsiri, S; Jumpangern, C; Israngkul Na Ayuthaya, I
2008-01-01
To investigate the optimal sensitometric curves of extended dose range (EDR2) radiographic film in terms of depth, field size, dose range and processing conditions for dynamic intensity modulated radiation therapy (IMRT) dosimetry verification with 6 MV X-ray beams. A Varian Clinac 23 EX linear accelerator with 6 MV X-ray beam was used to study the response of Kodak EDR2 film. Measurements were performed at depths of 5, 10 and 15 cm in MedTec virtual water phantom and with field sizes of 2x2, 3x3, 10x10 and 15x15 cm(2). Doses ranging from 20 to 450 cGy were used. The film was developed with the Kodak RP X-OMAT Model M6B automatic film processor. Film response was measured with the Vidar model VXR-16 scanner. Sensitometric curves were applied to the dose profiles measured with film at 5 cm in the virtual water phantom with field sizes of 2x2 and 10x10 cm(2) and compared with ion chamber data. Scanditronix/Wellhofer OmniPro(TM) IMRT software was used for the evaluation of the IMRT plan calculated by Eclipse treatment planning. Investigation of the reproducibility and accuracy of the film responses, which depend mainly on the film processor, was carried out by irradiating one film nine times with doses of 20 to 450 cGy. A maximum standard deviation of 4.9% was found which decreased to 1.9% for doses between 20 and 200 cGy. The sensitometric curves for various field sizes at fixed depth showed a maximum difference of 4.2% between 2x2 and 15x15 cm(2) at 5 cm depth with a dose of 450 cGy. The shallow depth tended to show a greater effect of field size responses than the deeper depths. The sensitometric curves for various depths at fixed field size showed slightly different film responses; the difference due to depth was within 1.8% for all field sizes studied. Both field size and depth effect were reduced when the doses were lower than 450 cGy. The difference was within 2.5% in the dose range from 20 to 300 cGy for all field sizes and depths studied. Dose profiles
Generation of intense high-order vortex harmonics.
Zhang, Xiaomei; Shen, Baifei; Shi, Yin; Wang, Xiaofeng; Zhang, Lingang; Wang, Wenpeng; Xu, Jiancai; Yi, Longqiong; Xu, Zhizhan
2015-05-01
This Letter presents for the first time a scheme to generate intense high-order optical vortices that carry orbital angular momentum in the extreme ultraviolet region based on relativistic harmonics from the surface of a solid target. In the three-dimensional particle-in-cell simulation, the high-order harmonics of the high-order vortex mode is generated in both reflected and transmitted light beams when a linearly polarized Laguerre-Gaussian laser pulse impinges on a solid foil. The azimuthal mode of the harmonics scales with its order. The intensity of the high-order vortex harmonics is close to the relativistic region, with the pulse duration down to attosecond scale. The obtained intense vortex beam possesses the combined properties of fine transversal structure due to the high-order mode and the fine longitudinal structure due to the short wavelength of the high-order harmonics. In addition to the application in high-resolution detection in both spatial and temporal scales, it also presents new opportunities in the intense vortex required fields, such as the inner shell ionization process and high energy twisted photons generation by Thomson scattering of such an intense vortex beam off relativistic electrons.
Effect of Variations in Long-Duration Rainfall Intensity on Unsaturated Slope Stability
Directory of Open Access Journals (Sweden)
Hsin-Fu Yeh
2018-04-01
Full Text Available In recent years, many scientific methods have been used to prove that the Earth’s climate is changing. Climate change can affect rainfall patterns, which can in turn affect slope safety. Therefore, this study analyzed the effects of climate change on rainfall patterns from the perspective of rainfall intensity. This analysis was combined with numerical model analysis to examine the rainfall patterns of the Zengwen reservoir catchment area and its effects on slope stability. In this study, the Mann–Kendall test and the Theil–Sen estimator were used to analyze the rainfall records of rainfall stations at Da-Dong-Shan, Ma-To-Shan, and San-Jiao-Nan-Shan. The rainfall intensity of the Zengwen reservoir catchment area showed an increasing trend from 1990–2016. In addition, the analysis results of rainfall intensity trends were used for qualitative analysis of seepage and slope stability. The trend analysis result showed that in the future, from 2017–2100, if the amount of rainfall per hour continues to rise at about 0.1 mm per year, the amount of seepage will increase at the slope surface boundary and significantly change pore water pressure in the soil. As a result, the time of the occurrence of slope instability after the start of rainfall will decrease from 20 to 13 h, and the reduction in the safety coefficient will increase from 32 to 41%. Therefore, to decrease the effects of slope disasters on the safety of the Zengwen reservoir and its surrounding areas, changes in rainfall intensity trends should be considered for slope safety in this region. However, the results of trend analyses were weak and future research is needed using a wider range of precipitation data and detailed hydrological analysis to better predict rainfall pattern variations.
Groot, de H.L.F.; Withagen, C.A.A.M.; Minliang, Z.
2004-01-01
This paper addresses the existence of an Environmental Kuznets Curve for China, using a sample of 30 regions, covering the period 1982–1997. The types of pollution included are wastewater, waste gas, and solid waste. We consider the development of the sources of pollution in a pooled cross-section
Directory of Open Access Journals (Sweden)
Rodrigo O. R. de M. Souza
2012-09-01
Full Text Available As equações de chuvas intensas têm sido usadas como ferramenta importante para o dimensionamento de obras hidráulicas. Devido à grande carência de informações relativas às equações de chuvas intensas, o presente trabalho teve como objetivo a obtenção das relações de intensidade, duração e frequência de precipitação pluvial para o Estado do Pará, utilizando-se a metodologia da desagregação da chuva de 24 h. Foram utilizadas séries históricas de dados pluviométricos de 74 cidades do Estado do Pará, obtidas no Sistema de Informações Hidrológicas da Agência Nacional de Águas-ANA. As equações de intensidade-duração-frequência foram devidamente ajustadas e apresentaram bom ajuste, com coeficientes de determinação acima de 0,99. A maioria das estações (51,4% apresentou intensidade de precipitação entre 90 e 110 mm h-1, para uma duração de chuva de 30 min e um tempo de retorno de 15 anos. Pode-se perceber uma concentração das maiores precipitações na região próxima ao litoral do nordeste paraense e no sudeste da Ilha do Marajó.The intense rainfall equations have been used as an important tool for design of hydraulic structures. Considering the lack of intense rainfall equations, this study aimed to determine the relations of intensity, duration and frequency of intense rainfall in the Pará State (Brazil, using the one-day rain disaggregation method. In this research rainfall data of 74 cities in the State of Pará were used, obtained from the Hydrological Information System of the National Water Agency-ANA. The equations of intensity-duration-frequency were adjusted and presented good adjustment with coefficients of determination above 0.99. Most stations (51.4% showed intensity of precipitation between 90 and 110 mm h-1 for duration of 30 min and rainfall return period of 15 years. The highest rainfall intensities were in the region near the northeast coast of Pará State and southeast of the Marajo
Orbital Noise of the Earth Causes Intensity Fluctuation in the Geomagnetic Field
Liu, Han-Shou; Kolenkiewicz, R.; Wade, C., Jr.
2003-01-01
Orbital noise of Earth's obliquity can provide an insight into the core of the Earth that causes intensity fluctuations in the geomagnetic field. Here we show that noise spectrum of the obliquity frequency have revealed a series of frequency periods centered at 250-, 1OO-, 50-, 41-, 30-, and 26-kyr which are almost identical with the observed spectral peaks from the composite curve of 33 records of relative paleointensity spanning the past 800 kyr (Sint-800 data). A continuous record for the past two million years also reveals the presence of the major 100 kyr periodicity in obliquity noise and geomagnetic intensity fluctuations. These results of correlation suggest that obliquity noise may power the dynamo, located in the liquid outer core of the Earth, which generates the geomagnetic field.
Ratkevicius, A; Skurvydas, A; Povilonis, E; Quistorff, B; Lexell, J
1998-04-01
The aims of this study were to investigate if low-frequency fatigue (LFF) dependent on the duration of repeated muscle contractions and to compare LFF in voluntary and electrically induced exercise. Male subjects performed three 9-min periods of repeated isometric knee extensions at 40% maximal voluntary contraction with contraction plus relaxation periods of 30 plus 60 s, 15 plus 30 s and 5 plus 10 s in protocols 1, 2 and 3, respectively. The same exercise protocols were repeated using feedback-controlled electrical stimulation at 40% maximal tetanic torque. Before and 15 min after each exercise period, knee extension torque at 1, 7, 10, 15, 20, 50 and 100 Hz was assessed. During voluntary exercise, electromyogram root mean square (EMGrms) of the vastus lateralis muscle was evaluated. The 20-Hz torque:100-Hz torque (20:100 Hz torque) ratio was reduced more after electrically induced than after voluntary exercise (P exercise, the decrease in 20:100 Hz torque ratio was gradually (P exercise, the decrease in 20:100 Hz torque ratio and the increase in EMGrms were greater in protocol 1 (P exercise and that the electrically induced exercise produced a more pronounced LFF compared to voluntary exercise of submaximal intensity. It is suggested that compensatory recruitment of faster-contracting motor units is an additional factor affecting the severity of LFF during voluntary exercise.
Directory of Open Access Journals (Sweden)
Henning Teismann
Full Text Available Tinnitus is one of the most common diseases in industrialized countries. Here, we developed and evaluated a short-term (5 subsequent days and intensive (6 hours/day tailor-made notched music training (TMNMT for patients suffering from chronic, tonal tinnitus. We evaluated (i the TMNMT efficacy in terms of behavioral and magnetoencephalographic outcome measures for two matched patient groups with either low (≤8 kHz, N = 10 or high (>8 kHz, N = 10 tinnitus frequencies, and the (ii persistency of the TMNMT effects over the course of a four weeks post-training phase. The results indicated that the short-term intensive TMNMT took effect in patients with tinnitus frequencies ≤8 kHz: subjective tinnitus loudness, tinnitus-related distress, and tinnitus-related auditory cortex evoked activity were significantly reduced after TMNMT completion. However, in the patients with tinnitus frequencies >8 kHz, significant changes were not observed. Interpreted in their entirety, the results also indicated that the induced changes in auditory cortex evoked neuronal activity and tinnitus loudness were not persistent, encouraging the application of the TMNMT as a longer-term training. The findings are essential in guiding the intended transfer of this neuro-scientific treatment approach into routine clinical practice.
A simple transformation for converting CW-OSL curves to LM-OSL curves
DEFF Research Database (Denmark)
Bulur, E.
2000-01-01
A simple mathematical transformation is introduced to convert from OSL decay curves obtained in the conventional way to those obtained using a linear modulation technique based on a linear increase of the stimulation light intensity during OSL measurement. The validity of the transformation...... was tested by the IR-stimulated luminescence curves from feldspars, recorded using both the conventional and the linear modulation techniques. The transformation was further applied to green-light-stimulated OSL from K and Na feldspars. (C) 2000 Elsevier Science Ltd. All rights reserved....
Rainfall Intensity and Frequency Explain Production Basis Risk in Cumulative Rain Index Insurance
Muneepeerakul, Chitsomanus P.; Muneepeerakul, Rachata; Huffaker, Ray G.
2017-12-01
With minimal moral hazard and adverse selection, weather index insurance promises financial resilience to farmers struck by harsh weather conditions through swift compensation at affordable premium. Despite these advantages, the very nature of indexing gives rise to production basis risk as the selected weather indexes do not sufficiently correspond to actual damages. To address this problem, we develop a stochastic yield model, built upon a stochastic soil moisture model driven by marked Poisson rainfall. Our analysis shows that even under similar temperature and rainfall amount yields can differ significantly; this was empirically supported by a 2-year field experiment in which rain-fed maize was grown under very similar total rainfall. Here, the year with more intense, less-frequent rainfall produces a better yield—a rare counter evidence to most climate change projections. Through a stochastic yield model, we demonstrate the crucial roles of rainfall intensity and frequency in determining the yield. Importantly, the model allows us to compute rainfall pattern-related basis risk inherent in cumulative rain index insurance. The model results and a case study herein clearly show that total rainfall is a poor indicator of yield, imposing unnecessary production basis risk on farmers and false-positive payouts on insurers. Incorporating rainfall intensity and frequency in the design of rain index insurance can offer farmers better protection, while maintaining the attractive features of the weather index insurance and thus fulfilling its promise of financial resilience.
Lavini, Cristina; Verhoeff, Joost J. C.; Majoie, Charles B.; Stalpers, Lukas J. A.; Richel, Dick J.; Maas, Mario
2011-01-01
To compare time intensity curve (TIC)-shape analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data with model-based analysis and semiquantitative analysis in patients with high-grade glioma treated with the antiangiogenic drug bevacizumab. Fifteen patients had a pretreatment
Wu, Fan; Cui, Xiaopeng; Zhang, Da-Lin; Qiao, Lin
2017-10-01
The relationship between lightning activity and rainfall associated with 2925 short-duration rainfall (SDR) events over the Beijing metropolitan region (BMR) is examined during the warm seasons of 2006-2007, using the cloud-to-ground (CG) and intracloud (IC) lightning data from Surveillance et Alerte Foudre par Interférometrie Radioélectrique (SAFIR)-3000 and 5-min rainfall data from automatic weather stations (AWSs). An optimal radius of 10 km around selected AWSs is used to determine the lightning-rainfall relationship. The lightning-rainfall correlations vary significantly, depending upon the intensity of SDR events. That is, correlation coefficient (R 0.7) for the short-duration heavy rainfall (SDHR, i.e., ≥ 20 mm h- 1) events is found higher than that (R 0.4) for the weak SDR (i.e., 5-10 mm h- 1) events, and lower percentage of the SDHR events (< 10%) than the weak SDR events (40-50%) are observed with few flashes. Significant time-lagged correlations between lightning and rainfall are also found. About 80% of the SDR events could reach their highest correlation coefficients when the associated lightning flashes shift at time lags of < 25 min before and after rainfall begins. Those events with lightning preceding rainfall account for 50-60% of the total SDR events. Better lightning-rainfall correlations can be attained when time lags are incorporated, with the use of total (CG and IC) lightning data. These results appear to have important implications for improving the nowcast of SDHR events.
SPITZER SPACE TELESCOPE MID-IR LIGHT CURVES OF NEPTUNE
Energy Technology Data Exchange (ETDEWEB)
Stauffer, John; Rebull, Luisa; Carey, Sean J.; Krick, Jessica; Ingalls, James G.; Lowrance, Patrick; Glaccum, William [Spitzer Science Center (SSC), California Institute of Technology, Pasadena, CA 91125 (United States); Marley, Mark S. [NASA Ames Research Center, Space Sciences and Astrobiology Division, MS245-3, Moffett Field, CA 94035 (United States); Gizis, John E. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kirkpatrick, J. Davy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Simon, Amy A. [NASA Goddard Space Flight Center, Solar System Exploration Division (690.0), 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Wong, Michael H. [University of California, Department of Astronomy, Berkeley CA 94720-3411 (United States)
2016-11-01
We have used the Spitzer Space Telescope in 2016 February to obtain high cadence, high signal-to-noise, 17 hr duration light curves of Neptune at 3.6 and 4.5 μ m. The light curve duration was chosen to correspond to the rotation period of Neptune. Both light curves are slowly varying with time, with full amplitudes of 1.1 mag at 3.6 μ m and 0.6 mag at 4.5 μ m. We have also extracted sparsely sampled 18 hr light curves of Neptune at W1 (3.4 μ m) and W2 (4.6 μ m) from the Wide-feld Infrared Survey Explorer ( WISE )/ NEOWISE archive at six epochs in 2010–2015. These light curves all show similar shapes and amplitudes compared to the Spitzer light curves but with considerable variation from epoch to epoch. These amplitudes are much larger than those observed with Kepler / K 2 in the visible (amplitude ∼0.02 mag) or at 845 nm with the Hubble Space Telescope ( HST ) in 2015 and at 763 nm in 2016 (amplitude ∼0.2 mag). We interpret the Spitzer and WISE light curves as arising entirely from reflected solar photons, from higher levels in Neptune’s atmosphere than for K 2. Methane gas is the dominant opacity source in Neptune’s atmosphere, and methane absorption bands are present in the HST 763 and 845 nm, WISE W1, and Spitzer 3.6 μ m filters.
Directory of Open Access Journals (Sweden)
Marianne eDavid
2015-11-01
Full Text Available Achieving perceptual gains in healthy individuals, or facilitating rehabilitation in patients is generally considered to require intense training to engage neuronal plasticity mechanisms. Recent work, however, suggested that beneficial outcome similar to training can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation (rSS. For example, high-frequency repetitive sensory stimulation (HF-rSS enhances tactile performance and induces cortical reorganization in healthy subjects and patients after stroke. Patients with complex regional pain syndrome (CRPS show impaired tactile performance associated with shrinkage of cortical maps. We here investigated the feasibility and efficacy of HF-rSS, and low-frequency rSS (LF-rSS to enhance tactile performance and reduce pain intensity in 20 patients with CRPS type I. Intermittent high or low frequency electrical stimuli were applied for 45min/day to all fingertips of the affected hand for 5 days. Main outcome measures were spatial 2-point-discrimination thresholds and mechanical detection thresholds measured on the tip of the index finger bilaterally. Secondary endpoint was current pain intensity. All measures were assessed before and on day 5 after the last stimulation session. HF-rSS applied in 16 patients improved tactile discrimination on the affected hand significantly without changes contralaterally. Current pain intensity remained unchanged on average, but decreased in 4 patients by 30%. This limited pain relief might be due to the short stimulation period of 5 days only. In contrast, after LF-rSS, tactile discrimination was impaired in all 4 patients, while detection thresholds and pain were not affected. Our data suggest that HF-rSS could be used as a novel approach in CRPS treatment to improve sensory loss. Longer treatment periods might be required to induce consistent pain relief.
Distal clavicular osteolysis in adults: association with bench pressing intensity
International Nuclear Information System (INIS)
Nevalainen, Mika T.; Morrison, William B.; Zoga, Adam C.; Roedl, Johannes B.; Ciccotti, Michael G.
2016-01-01
To investigate the association between distal clavicular osteolysis (DCO) and bench pressing intensity. From a retrospective review of MRI shoulder reports of individuals between 20 and 40 years of age, 262 male patients with DCO and 227 age-matched male patients without DCO were selected. All patients had completed a bench pressing questionnaire. The patients' bench pressing frequency (times per week), duration (years of bench pressing), bench pressing weight (maximum bench pressing weight with one repetition = 1RM) and the ratio of bench pressing weight to body weight were compared between both groups using Chi-square and Mann-Whitney tests. The results showed that 56 % (146/262) of patients with DCO were high-intensity bench pressers (1RM more than 1.5 times the body weight) compared to 6 % (14/227) in patients without DCO. High-intensity bench pressing was a risk factor for DCO (OR = 19; 95 %CI = 11-35; p 1 x /week) and duration (>5 years) of bench pressing were risk factors. In bench pressers who suffered from DCO, the mean 1RM was 283 lbs (±SD 57) compared to 209 lbs (±SD 60) in bench pressers not affected by DCO (p < 0.001, Mann-Whitney). High-intensity, but not low-intensity bench pressing is a risk factor for DCO. (orig.)
Chapin, Thomas
2015-01-01
Hand-collected grab samples are the most common water sampling method but using grab sampling to monitor temporally variable aquatic processes such as diel metal cycling or episodic events is rarely feasible or cost-effective. Currently available automated samplers are a proven, widely used technology and typically collect up to 24 samples during a deployment. However, these automated samplers are not well suited for long-term sampling in remote areas or in freezing conditions. There is a critical need for low-cost, long-duration, high-frequency water sampling technology to improve our understanding of the geochemical response to temporally variable processes. This review article will examine recent developments in automated water sampler technology and utilize selected field data from acid mine drainage studies to illustrate the utility of high-frequency, long-duration water sampling.
An efficient power market - consequences for energy-intensive industries and regions
International Nuclear Information System (INIS)
Bye, Torstein; Hoel, Michael; Stroem, Steinar
2000-01-01
From economic theory we know that, unless special arguments can be made, we obtain economic efficiency if all buyers of a homogeneous good pay the same price for the good. If this principle is violated inefficiency will occur. The principle holds for all goods, i.e. both for consumer goods (e.g. clothing or food), inputs in a production process (e.g. raw materials), and for combined goods. Electricity is an example of a combined good that can be used both as a final good and as an input in production processes. In Norway, the energy intensive industry (metals and chemicals) and the paper and pulp industry pay a lower price for their use of electricity than other users pay. The reason is that this industry has signed long-term contracts where the prices have been influenced by political processes. This pricing leads to an inefficient use of electricity in Norway. In this book we study the consequences of changing the electricity prices for this sectors so that we obtain a situation where all domestic users of electricity pay the same price. The book contains numerical calculations of potential structural changes and changes in overall economic welfare (producer and consumer surplus). We also calculate changes in emissions both from these sectors and from the rest of the economy. The last chapter deals with structural change and regional differences, with emphasis on the regions in which the energy intensive firms are located. We discuss how strong the negative impact on these regions will be as a consequence of shutting down non-profitable energy intensive firms when the price of electricity changes. A main conclusion in the book is that Norway will benefit from increasing the electricity price paid by the energy intensive sectors, both in economic terms and with respect to overall pollution. Reduced electricity use in the energy intensive sectors will in the short run lead to increased export of electricity. In the longer run, new investments in power producing
Secondhand Smoke Exposure, Restless Sleep, and Sleep Duration in Adolescents
Directory of Open Access Journals (Sweden)
Jennifer Schwartz
2014-01-01
Full Text Available Purpose. To examine whether secondhand smoke (SHS exposure is associated with restless sleep and/or nighttime sleep duration among adolescents. Methods. Data were analyzed from 1,592 adolescents who completed an internet-delivered survey as part of the British Columbia Adolescent Substance Use Survey cohort study. Ordinal logistic and linear regression models were used to examine associations between frequency of SHS exposure in the past month and frequency of restless sleep and nighttime sleep duration, respectively. Results. SHS exposure was significantly positively associated with restless sleep and significantly negatively associated with sleep duration. In fully adjusted models, compared with students who reported never being exposed to SHS in the past month, students who reported a low, medium, or high frequency of SHS exposure were 1.53, 1.76, and 2.51 times as likely, respectively, to report more frequent restless sleep (OR=1.53, 95% CI 1.08–2.16; OR=1.76, 95% CI 1.22–2.53; OR=2.51, 95% CI 1.59–3.98. With regard to sleep duration, as frequency of SHS exposure increased by one category, nighttime sleep duration during the week and weekend decreased by 4 minutes (B=-0.06, 95% CI=-0.01–-0.11 and 6 minutes (B=-0.09, 95% CI=-0.03–-0.14, respectively. Conclusions. This study suggests that frequency of SHS exposure has a significant dose-response relationship with restless sleep and sleep duration in adolescents.
Directory of Open Access Journals (Sweden)
Giovana Mara Rodrigues Borges
2016-11-01
Full Text Available Knowledge of the probabilistic behavior of rainfall is extremely important to the design of drainage systems, dam spillways, and other hydraulic projects. This study therefore examined statistical models to predict annual daily maximum rainfall as well as models of heavy rain for the city of Formiga - MG. To do this, annual maximum daily rainfall data were ranked in decreasing order that best describes the statistical distribution by exceedance probability. Daily rainfall disaggregation methodology was used for the intense rain model studies and adjusted with Intensity-Duration-Frequency (IDF and Exponential models. The study found that the Gumbel model better adhered to the data regarding observed frequency as indicated by the Chi-squared test, and that the exponential model best conforms to the observed data to predict intense rains.
Wang, Xin; Jen, Philip H-S; Wu, Fei-Jian; Chen, Qi-Cai
2007-09-05
In acoustic communication, animals must extract biologically relevant signals that are embedded in noisy environment. The present study examines how weak noise may affect the auditory sensitivity of neurons in the central nucleus of the mouse inferior colliculus (IC) which receives convergent excitatory and inhibitory inputs from both lower and higher auditory centers. Specifically, we studied the frequency sensitivity and minimum threshold of IC neurons using a pure tone probe and a weak white noise masker under forward masking paradigm. For most IC neurons, probe-elicited response was decreased by a weak white noise that was presented at a specific gap (i.e. time window). When presented within this time window, weak noise masking sharpened the frequency tuning curve and increased the minimum threshold of IC neurons. The degree of weak noise masking of these two measurements increased with noise duration. Sharpening of the frequency tuning curve and increasing of the minimum threshold of IC neurons during weak noise masking were mostly mediated through GABAergic inhibition. In addition, sharpening of frequency tuning curve by the weak noise masker was more effective at the high than at low frequency limb. These data indicate that in the real world the ambient noise may improve frequency sensitivity of IC neurons through GABAergic inhibition while inevitably decrease the frequency response range and sensitivity of IC neurons.
Effects of single cycle binaural beat duration on auditory evoked potentials.
Mihajloski, Todor; Bohorquez, Jorge; Özdamar, Özcan
2014-01-01
Binaural beat (BB) illusions are experienced as continuous central pulsations when two sounds with slightly different frequencies are delivered to each ear. It has been shown that steady-state auditory evoked potentials (AEPs) to BBs can be captured and investigated. The authors recently developed a new method of evoking transient AEPs to binaural beats using frequency modulated stimuli. This methodology was able to create single BBs in predetermined intervals with varying carrier frequencies. This study examines the effects of the BB duration and the frequency modulating component of the stimulus on the binaural beats and their evoked potentials. Normal hearing subjects were tested with a set of four durations (25, 50, 100, and 200 ms) with two stimulation configurations, binaural dichotic (binaural beats) and diotic (frequency modulation). The results obtained from the study showed that out of the given durations, the 100 ms beat, was capable of evoking the largest amplitude responses. The frequency modulation effect showed a decrease in peak amplitudes with increasing beat duration until their complete disappearance at 200 ms. Even though, at 200 ms, the frequency modulation effects were not present, the binaural beats were still perceived and captured as evoked potentials.
Study on the specificity of yeast cell damage by high-intensity UV radiation (266nm)
International Nuclear Information System (INIS)
Burchuladze, T.G.; Frajkin, G.Ya.; Rubin, L.B.
1981-01-01
Peculiarities of photoreactivation and photoprotection of the Candida guilliermondii and Candida utilis yeast cells, irradiated with far and near ultraviolet radiation, are considered. New results on the study of the dependence of the cells inactivation degree on the intensity of ultraviolet radiation are presented. The impulse rate density at 266 nm reached 10 10 Ix m -2 xs -1 at the impulse duration of 10 -8 s. Survival curves of the yeast cells during their irradiation with ultraviolet radiation of 266 nm and 254 nm are given. It is shown that with the increase of the irradiation intensity of 266 nm the rates and final levels of photoreactivation decrease. Under the effect of ultraviolet irradiation of high intensity contribution of pyrimidine dimers to the cell inactivation decreases [ru
Yield Frequency Spectra and seismic design of code-compatible RC structures: an illustrative example
DEFF Research Database (Denmark)
Katsanos, Evangelos; Vamvatsikos, Dimitrios
2017-01-01
with given yield displacement and capacity curve shape. For the 8-story case study building, deformation checking is the governing limit state. A conventional code-based design was performed using seismic intensities tied to the desired MAF for safety checking. Then, the YFS-based approach was employed......The seismic design of an 8-story reinforced concrete space frame building is undertaken using a Yield Frequency Spectra (YFS) performance-based approach. YFS offer a visual representation of the entire range of a system’s performance in terms of the mean annual frequency (MAF) of exceeding...... to redesign the resulting structure working backwards from the desired MAF of response (rather than intensity) to estimate an appropriate value of seismic intensity for use within a typical engineering design process. For this high-seismicity and high-importance midrise building, a stiffer system with higher...
Towards Coupling of Macroseismic Intensity with Structural Damage Indicators
Kouteva, Mihaela; Boshnakov, Krasimir
2016-04-01
Knowledge on basic data of ground motion acceleration time histories during earthquakes is essential to understanding the earthquake resistant behaviour of structures. Peak and integral ground motion parameters such as peak ground motion values (acceleration, velocity and displacement), measures of the frequency content of ground motion, duration of strong shaking and various intensity measures play important roles in seismic evaluation of existing facilities and design of new systems. Macroseismic intensity is an earthquake measure related to seismic hazard and seismic risk description. Having detailed ideas on the correlations between the earthquake damage potential and macroseismic intensity is an important issue in engineering seismology and earthquake engineering. Reliable earthquake hazard estimation is the major prerequisite to successful disaster risk management. The usage of advanced earthquake engineering approaches for structural response modelling is essential for reliable evaluation of the accumulated damages in the existing buildings and structures due to the history of seismic actions, occurred during their lifetime. Full nonlinear analysis taking into account single event or series of earthquakes and the large set of elaborated damage indices are suitable contemporary tools to cope with this responsible task. This paper presents some results on the correlation between observational damage states, ground motion parameters and selected analytical damage indices. Damage indices are computed on the base of nonlinear time history analysis of test reinforced structure, characterising the building stock of the Mediterranean region designed according the earthquake resistant requirements in mid XX-th century.
The Noisiness of Low Frequency Bands of Noise
Lawton, B. W.
1975-01-01
The relative noisiness of low frequency 1/3-octave bands of noise was examined. The frequency range investigated was bounded by the bands centered at 25 and 200 Hz, with intensities ranging from 50 to 95 db (SPL). Thirty-two subjects used a method of adjustment technique, producing comparison band intensities as noisy as 100 and 200 Hz standard bands at 60 and 72 db. The work resulted in contours of equal noisiness for 1/3-octave bands, ranging in intensity from approximately 58 to 86 db (SPL). These contours were compared with the standard equal noisiness contours; in the region of overlap, between 50 and 200 Hz, the agreement was good.
Directory of Open Access Journals (Sweden)
Fabiane Aparecida de Souza Retslaff
2015-06-01
Full Text Available The study aimed to fit mathematical models for the construction of Site Index curves and to estimate heights at different ages for Eucalyptus grandis in the Campos Gerais region, Parana State. The data used to fit the models came from permanent, temporary plots and pre-harvesting inventory, covering ages from 2.5 to 26.5 years. Several models were tested to represent the sites and the hypsometric relationship. The Site Index curves were constructed by the guide-curve method. For the Site Index, the Chapman-Richards model showed the best fit and precision statistics, generating 5 Site Index curves (range of 5 m with the Chapman-Richards model. The four hypsometric models tested showed satisfactory performance and similar statistics and the inclusion of the variables dominant height or site index did not substantially improve the goodness of fit statistics, but the residues were more homogeneous and closer to zero.
International Nuclear Information System (INIS)
Tsurutani, B.T.; Gonzalez, W.D.
1987-01-01
It is shown that high intensity (AE > 1,000 nT), long duration (T > 2 d) continuous auroral activity (HILDCAA) events are caused by outward (from the sun) propagating interplanetary Alfven wave trains. The Alfven waves are often (but not always) detected several days after major interplanetary events, such as shocks and solar wind density enhancements. Presumably magnetic reconnection between the southward components of the Alfven wave magnetic fields and magnetospheric fields is the mechanism for transfer of solar wind energy to the magnetosphere. If the stringent requirements for HILDCAA events are relaxed, there are many more AE events of this type. A brief inspection indicates that these are also related to interplanetary Alfvenic fluctuations. We therefore suggest that most auroral activity may be caused by reconnection associated with Alfven waves in the interplanetary medium. (author)
Johnsson, Mark J.; Ellen, Stephen D.; McKittrick, Mary Anne
1993-01-01
Orographic precipitation on the southern flank of the southeastern Koolau Mountains produces a pronounced precipitation gradient. The corresponding gradient in the intensity of the chemical weathering environment provides an opportunity to address the effects of varying chemical weathering intensity on the composition of clay-size weathering products in soils developed on basalt. In addition, little-modified remnants of the constructional surface of the Koolau Volcano, isolated by stream dissection, remain as facets on the southern ends of the parallel ridges of the study area. By comparing clay mineralogy of soils developed on these older geomorphic surfaces with those developed on the younger sharp-crested ridges and steep side slopes, the effects of weathering duration on clay mineralogy can also be addressed.Soil clays in this part of the Koolau Mountains are mineralogically complex; principal phases include smectite, kaolinite, and halloysite, but pure end member phases are uncommon. Rather, most phases contain some amount of mixed layering. Smectite may contain small (Volcano are markedly more leached than those from younger landscapes in the same precipitation regime. Although smectite may be present, kaolinite is the dominant phase, and accumulations of Fe and Ti occur in the uppermost soil levels. Enrichment of Zr and Ti in these soils, as compared to concentrations in the original basaltic parent material, indicates that as much as 75% of the parent material has been lost. Thus weathering duration may affect soil clay composition in the same way as weathering intensity.Because smectite and halloysite are expandable clay minerals, their presence in soils may decrease slope stability and influence the nature of slope processes. Soil avalanches occur on steep slopes throughout the study area, whereas slow-moving landslides appear to be restricted to gentler slopes in drier parts of the study area where smectite is abundant. The clay mineralogy of soils thus
Measuring consciousness: Task accuracy and awareness as sigmoid functions of stimulus duration
DEFF Research Database (Denmark)
Sandberg, Kristian; Bibby, Bo Martin; Timmermans, B
2011-01-01
certain limitations. In the present article, we propose describing task accuracy and awareness as functions of stimulus intensity (thus obtaining an accuracy and an awareness curve) as suggested by Koch and Preuschoff (2007). The estimated lag between the curves describes how much stimulus intensity must...
In Situ Measurement of Discomfort Curves for Seated Subjects in a Car on the Four-Post Rig
Directory of Open Access Journals (Sweden)
T. Ibicek
2014-01-01
Full Text Available The aim of this study is to measure and quantify perceived intensity of discomfort due to vibration in a vehicle in situ considering complete vehicle dynamic behaviour. The shaker table based discomfort curves or the road test results may not accurately and universally indicate the true level of human discomfort in a vehicle. A new experimental method, using a seated human in a car on the four-post rig simulator, is proposed to quantify discomfort. The intensity of perception to vibration decreased with decreasing input and increasing frequency; the rate of change is different from the published literature; the difference is large for angular modes of inputs. Vehicle dynamic response is used to inform and analyse the results. The repeatability of the method and the fact that they are in situ measurements may eventually help reduce reliance on the road tests. Furthermore, discomfort curves obtained, subsequently, can be used in predictive models.
[Evaluation of the learning curve of residents in localizing a phantom target with ultrasonography].
Dessieux, T; Estebe, J-P; Bloc, S; Mercadal, L; Ecoffey, C
2008-10-01
Few information are available regarding the learning curve in ultrasonography and even less for ultrasound-guided regional anesthesia. This study aimed to evaluate in a training program the learning curve on a phantom of 12 residents novice in ultrasonography. Twelve trainees inexperienced in ultrasonography were given introductory training consisting of didactic formation on the various components of the portable ultrasound machine (i.e. on/off button, gain, depth, resolution, and image storage). Then, students performed three trials, in two sets of increased difficulty, at executing these predefined tasks: adjustments of the machine, then localization of a small plastic piece introduced into roasting pork (3 cm below the surface). At the end of the evaluation, the residents were asked to insert a 22 G needle into an exact predetermined target (i.e. point of fascia intersection). The progression of the needle was continuously controlled by ultrasound visualization using injection of a small volume of water (needle perpendicular to the longitudinal plane of the ultrasound beam). Two groups of two different examiners evaluated for each three trials the skill of the residents (quality, time to perform the machine adjustments, to localize the plastic target, and to hydrolocalize, and volume used for hydrolocalization). After each trial, residents evaluated their performance using a difficulty scale (0: easy to 10: difficult). All residents performed the adjustments from the last trial of each set, with a learning curve observed in terms of duration. Localization of the plastic piece was achieved by all residents at the 6th trial, with a shorter duration of localization. Hydrolocalization was achieved after the 4th trial by all subjects. Difficulty scale was correlated to the number of trials. All these results were independent of the experience of residents in regional anesthesia. Four trials were necessary to adjust correctly the machine, to localize a target, and to
Distribution functions for the linear region of the S-N curve
Energy Technology Data Exchange (ETDEWEB)
Mueller, Christian; Waechter, Michael; Masendorf, Rainer; Esderts, Alfons [TU Clausthal, Clausthal-Zellerfeld (Germany). Inst. for Plant Engineering and Fatigue Analysis
2017-08-01
This study establishes a database containing the results of fatigue tests from the linear region of the S-N curve using sources from the literature. Each set of test results originates from testing metallic components on a single load level. Eighty-nine test series with sample sizes of 14 ≤ n ≤ 500 are included in the database, resulting in a sum of 6,086 individual test results. The test series are tested in terms of the type of distribution function (log-normal or 2-parameter Weibull) using the Shapiro-Wilk test, the Anderson-Darling test and probability plots. The majority of the tested individual test results follows a log-normal distribution.
Distribution of isodose curves in urological surgical procedures
International Nuclear Information System (INIS)
Lanfredi, M.P.; Dias, J.H.; Ravazio, R.C.; Anés, M.; Bacelar, A.; Lykawka, R.
2017-01-01
During urological surgical procedures with fluoroscopy, the doses of the care team may be significant. However, the knowledge of the occupational exposure of these professionals is still very incipient in the national surgical centers. The objective of the study is to determine the isodose curves of the urological surgical procedures, in order to estimate the exposure of the personnel involved. The equipment used was a Arco-C BV Philips Bracelet. Patients with thicknesses of 20 and 28 cm were simulated using acrylic plates. The dose rates were measured with RaySafe i2 Unfors dosimeters positioned in a 50 x 50 cm mesh at three different heights of the floor: 95, 125 and 165 centimeters respectively corresponding to the gonadal, thoracic and crystalline regions of a typical adult . The isodose curves applied to the distribution of the surgical team suggest that the exposures are in the following descending order of intensity: primary physician, auxiliary physician, scrub nurse, anesthetist and nurse
Regional frequency analysis of extreme rainfalls using partial L moments method
Zakaria, Zahrahtul Amani; Shabri, Ani
2013-07-01
An approach based on regional frequency analysis using L moments and LH moments are revisited in this study. Subsequently, an alternative regional frequency analysis using the partial L moments (PL moments) method is employed, and a new relationship for homogeneity analysis is developed. The results were then compared with those obtained using the method of L moments and LH moments of order two. The Selangor catchment, consisting of 37 sites and located on the west coast of Peninsular Malaysia, is chosen as a case study. PL moments for the generalized extreme value (GEV), generalized logistic (GLO), and generalized Pareto distributions were derived and used to develop the regional frequency analysis procedure. PL moment ratio diagram and Z test were employed in determining the best-fit distribution. Comparison between the three approaches showed that GLO and GEV distributions were identified as the suitable distributions for representing the statistical properties of extreme rainfall in Selangor. Monte Carlo simulation used for performance evaluation shows that the method of PL moments would outperform L and LH moments methods for estimation of large return period events.
Eating behavior in humans, characterized by cumulative food intake curves--a review.
Westerterp-Plantenga, M S
2000-03-01
Cumulative food intake curves have been obtained by monitoring eating from a plate, placed on a scale built into a table, and connected to a digital computer. They describe and integrate parameters of consumption of an ad lib single course meal, i.e. meal size, meal duration, eating rate, change in eating rate, bite size and bite frequency. It is concluded that they are an adequate tool for analyzing dietary and clinical interventions on meal size, because the cumulative food intake curve parameters: are stable and consistent within subjects; show a clear relationship with the subject characteristics dietary restraint and obesity; show a clear relationship with the physiological parameters satiation, diet-induced thermogenesis and body-temperature near the liver, and with the cognitive parameter: estimating forthcoming ingestion; are sensitive to instructions, clinical and dietary interventions (preloads, palatability, energy density, macronutrient composition), and to a state of negative energy balance. Because of possible compensatory post-prandial effects, it is suggested that assessment of meal size should be part of a 24 h appetite profile and food intake observation.
Beemsterboer, Willibrord; Stewart, Roy; Groothoff, Johan; Nijhuis, Frans
2009-01-01
Objectives: To explore regional differences in the effects of the sick leave frequency determinants between two homogeneous groups of workers from two comparable socio-economic regions in the Netherlands, namely Utrecht and South Limburg. Materials and Methods: Data on sick leave frequency for 137
Rainfall intensity-duration thresholds for postfire debris-flow emergency-response planning
Cannon, S.H.; Boldt, E.M.; Laber, J.L.; Kean, J.W.; Staley, D.M.
2011-01-01
Following wildfires, emergency-response and public-safety agencies can be faced with evacuation and resource-deployment decisions well in advance of coming winter storms and during storms themselves. Information critical to these decisions is provided for recently burned areas in the San Gabriel Mountains of southern California. A compilation of information on the hydrologic response to winter storms from recently burned areas in southern California steeplands is used to develop a system for classifying magnitudes of hydrologic response. The four-class system describes combinations of reported volumes of individual debris flows, consequences of debris flows and floods in an urban setting, and spatial extents of the hydrologic response. The range of rainfall conditions associated with different magnitude classes is defined by integrating local rainfall data with the response magnitude information. Magnitude I events can be expected when within-storm rainfall accumulations (A) of given durations (D) fall above the threshold A = 0.4D0.5 and below A = 0.5D0.6 for durations greater than 1 h. Magnitude II events will be generated in response to rainfall accumulations and durations between A = 0.4D0.5 and A = 0.9D0.5 for durations less than 1 h, and between A = 0.5D0.6 and A = 0.9D0.5 or durations greater than 1 h. Magnitude III events can be expected in response to rainfall conditions above the threshold A = 0.9D0.5. Rainfall threshold-magnitude relations are linked with potential emergency-response actions as an emergency-response decision chart, which leads a user through steps to determine potential event magnitudes and identify possible evacuation and resource-deployment levels. Use of this information in planning and response decision-making process could result in increased safety for both the public and emergency responders. ?? 2011 US Government.
International Nuclear Information System (INIS)
Nerkararyan, A.V.; Shahinyan, M.A.; Khachatryan, A.V.; Vardevanyan, P.O.
2011-01-01
In this work the influence of non-thermal coherent electromagnetic radiation (EMR) with low intensity and extremely high frequency on intensity of wheat developing germ metabolism has been investigated. Particularly, total activity and isoenzymatic composition of peroxidase of germ cells have been determined during their growth. The role of water in formation of organism response reaction to the external physical field effect has also been investigated. It has been shown, that water appears to be a primary element of extremely high frequency EMR effect on bio system. Extremely high frequency EMR irradiation of germinating seeds and the cultivation of dry seeds and their germs by irradiated water stimulate peroxidase synthesis in germ cells. The redistribution of quantitative composition of peroxidase molecular forms takes place in germ cells effected by EMR with extremely high frequency and low intensity
Effect of stellar activity on the high precision transit light curve
Directory of Open Access Journals (Sweden)
Oshagh, M.
2015-01-01
Full Text Available Stellar activity features such as spots and plages can create difficulties in determining planetary parameters through spectroscopic and photometric observations. The overlap of a transiting planet and a stellar spot, for instance, can produce anomalies in the transit light curve that may lead to inaccurate estimation of the transit duration, depth, and timing. Such inaccuracies can affect the precise derivation of the planet’s radius. In this talk we will present the results of a quantitative study on the effects of stellar spots on high precision transit light curves. We show that spot anomalies can lead to the estimate of a planet radius that is 4% smaller than the real value. The effects on the transit duration can also be of the order of 4%, longer or shorter. Depending on the size and distribution of spots, anomalies can also produce transit timing variations with significant amplitudes. For instance, TTVs with signal amplitudes of 200 seconds can be produced by spots as large as the largest sunspot. Finally, we examine the impact of active regions on the transit depth measurements in different wavelengths, in order to probe the impact of this effect on transmission spectroscopy measurements. We show that significant (up to 10% underestimation/overestimation of the planet-to-star radius ratio can be measured, especially in the short wavelength regime.
Energy Technology Data Exchange (ETDEWEB)
Heidarvand, Majid; Soltani, Naser; Hajializadeh, Farshid [University of Tehran, Tehran (Iran, Islamic Republic of)
2017-05-15
We determined the fracture toughness of aluminum curved thin sheets using tensile stress tests and finite element method. We applied Linear elastic fracture mechanics (LEFM) and Feddersen procedure to evaluate stress intensity factor of the samples with central wire-cut cracks and fatigue cracks with different lengths to investigate the notch radius effect. Special fixture design was utilized to establish uniform stress distribution at the crack zone. Less than 9 % difference was found between the wire-cut and the fatigue cracked samples. Since generating central fatigue crack with different lengths required so much effort, wire-cut cracked samples were used to determine critical stress intensity factor. Finite element analysis was also performed on one-quarter of the specimen using both the singular Borsum elements and the regular isoparametric elements to further investigate fracture toughness of the samples. It was observed that the singular elements presented better results than the isoparametric ones. A slight difference was also found between the results obtained from finite element method using singular elements and the experimental results.
DEFF Research Database (Denmark)
Demant, Helle; Ladewig, Jan; Balsby, Thorsten Johannes Skovbjerg
2011-01-01
dogs such as guide dogs and police dogs, also the training of family dogs can benefit from this knowledge. We studied the effect of frequency and duration of training sessions on acquisition and on long-term memory. Forty-four laboratory Beagles were divided into 4 groups and trained by means......Most domestic dogs are subjected to some kind of obedience training, often on a frequent basis, but the question of how often and for how long a dog should be trained has not been fully investigated. Optimizing the training as much as possible is not only an advantage in the training of working...
Power curve report - with turbulence intensity normalization
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Wagner, Rozenn; Vesth, Allan
, additional shear and turbulence intensitity filters are applied on the measured data. Secondly, the method for normalization to a given reference turbulence intensity level (as described in Annex M of the draft of IEC 61400-12-1 Ed.2 [3]) is applied. The measurements have been performed using DTU...
On the Influence of Global Warming on Atlantic Hurricane Frequency
Hosseini, S. R.; Scaioni, M.; Marani, M.
2018-04-01
In this paper, the possible connection between the frequency of Atlantic hurricanes to the climate change, mainly the variation in the Atlantic Ocean surface temperature has been investigated. The correlation between the observed hurricane frequency for different categories of hurricane's intensity and Sea Surface Temperature (SST) has been examined over the Atlantic Tropical Cyclogenesis Regions (ACR). The results suggest that in general, the frequency of hurricanes have a high correlation with SST. In particular, the frequency of extreme hurricanes with Category 5 intensity has the highest correlation coefficient (R = 0.82). In overall, the analyses in this work demonstrates the influence of the climate change condition on the Atlantic hurricanes and suggest a strong correlation between the frequency of extreme hurricanes and SST in the ACR.
Vibrational Analysis of Curved Single-Walled Carbon Nanotube on a Pasternak Elastic Foundation
DEFF Research Database (Denmark)
Mehdipour, I.; Barari, Amin; Kimiaeifar, Amin
2012-01-01
. By utilizing He’s Energy Balance Method (HEBM), the relationships of the nonlinear amplitude and frequency were expressed for a curved, single-walled carbon nanotube. The amplitude frequency response curves of the nonlinear free vibration were obtained for a curved, single-walled carbon nanotube embedded...
High frequency ion sound waves associated with Langmuir waves in type III radio burst source regions
Directory of Open Access Journals (Sweden)
G. Thejappa
2004-01-01
Full Text Available Short wavelength ion sound waves (2-4kHz are detected in association with the Langmuir waves (~15-30kHz in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir waves occur as coherent field structures with peak intensities exceeding the Langmuir collapse thresholds. Their scale sizes are of the order of the wavelength of an ion sound wave. These Langmuir wave field characteristics indicate that the observed short wavelength ion sound waves are most probably generated during the thermalization of the burnt-out cavitons left behind by the Langmuir collapse. Moreover, the peak intensities of the observed short wavelength ion sound waves are comparable to the expected intensities of those ion sound waves radiated by the burnt-out cavitons. However, the speeds of the electron beams derived from the frequency drift of type III radio bursts are too slow to satisfy the needed adiabatic ion approximation. Therefore, some non-linear process such as the induced scattering on thermal ions most probably pumps the beam excited Langmuir waves towards the lower wavenumbers, where the adiabatic ion approximation is justified.
Assessment of homogeneity of regions for regional flood frequency analysis
Lee, Jeong Eun; Kim, Nam Won
2016-04-01
This paper analyzed the effect of rainfall on hydrological similarity, which is an important step for regional flood frequency analysis (RFFA). For the RFFA, storage function method (SFM) using spatial extension technique was applied for the 22 sub-catchments that are partitioned from Chungju dam watershed in Republic of Korea. We used the SFM to generate the annual maximum floods for 22 sub-catchments using annual maximum storm events (1986~2010) as input data. Then the quantiles of rainfall and flood were estimated using the annual maximum series for the 22 sub-catchments. Finally, spatial variations in terms of two quantiles were analyzed. As a result, there were significant correlation between spatial variations of the two quantiles. This result demonstrates that spatial variation of rainfall is an important factor to explain the homogeneity of regions when applying RFFA. Acknowledgements: This research was supported by a grant (11-TI-C06) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.
International Nuclear Information System (INIS)
Torgomyan, Heghine; Trchounian, Armen
2011-01-01
Highlights: → Low intensity 70.6 and 73 GHz electromagnetic irradiation (EMI) strongly suppressed Escherichia coli growth at 73 GHz and pH 7.3. → Reducer DL-dithiothreitol had bactericidal effect and disturbed the SH-groups number. → EMI enhanced E. coli sensitivity toward dithiothreitol. → EMI decreased the SH-groups number of membrane disturbed by ATP and N,N'-dicyclohexycarbodiimide. → The changed membrane oxidation-reduction state could be the primary mechanisms in EMI effects. -- Abstract: Low-intensity electromagnetic irradiation (EMI) of 70.6 and 73 GHz frequencies (flux capacity - 0.06 mW cm -2 ) had bactericidal effects on Escherichia coli. This EMI (1 h) exposure suppressed the growth of E. coli K-12(λ). The pH value (6.0-8.0) did not significantly affect the growth. The lag-phase duration was prolonged, and the growth specific rate was inhibited, and these effects were more noticeable after 73 GHz irradiation. These effects were enhanced by the addition of DL-dithiothreitol (DTT), a strong reducer of disulfide bonds in surface membrane proteins, which in its turn also has bactericidal effect. Further, the number of accessible SH-groups in membrane vesicles was markedly decreased by EMI that was augmented by N,N'-dicyclohexycarbodiimide and DTT. These results indicate a change in the oxidation-reduction state of bacterial cell membrane proteins that could be the primary membranous mechanism in the bactericidal effects of low-intensity EMI of the 70.6 and 73 GHz frequencies.
Kabata, Yasuo; Higashi, Yukihiro; Uematsu, Masahiko; Watanabe, Koichi
Measurements of the vapor-liquid coexistence curve in the critical region for the refrigerant mixture of R152a (CH3CHF2: 1, l-difluoroethane) +R 114 (CCIF2CCIF2 :1, 2-dichloro-1, 1, 2, 2-tetrafluoroethane) system were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Forty-eight saturated densities along the vapor-liquid coexistence curve between 204 and 861 kg·m-3 for five different compositions of 10, 20, 50, 80 and 90 wt% R 152a were obtained in the temperature range 370 to 409 K. The experimental errors of temperature, density, and mass fraction were estimated within ±10mK, ±0.5% and +0.05 %, respectively. On the basis of these measurements, the critical parameters of five different compositions for the R 152a +R 114 system were determined in consideration of the meniscus disappearance level as well as intensity of the critical opalescence. In accordance with the previous results of three other refrigerant mixtures, i.e., R 12 +R 22 system, R 22 +R 114 system and R 13B1 + R 114 system, the coexistence curve and critical curve on the temperature-density diagram for binary refrigerant mixtures were discussed. In addition, correlations of its composition dependence for this system were proposed.
Prediction of maximum earthquake intensities for the San Francisco Bay region
Borcherdt, Roger D.; Gibbs, James F.
1975-01-01
The intensity data for the California earthquake of April 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the empirical relation derived between 1906 intensities and distance perpendicular to the fault for 917 sites underlain by rocks of the Franciscan Formation is: Intensity = 2.69 - 1.90 log (Distance) (km). For sites on other geologic units intensity increments, derived with respect to this empirical relation, correlate strongly with the Average Horizontal Spectral Amplifications (AHSA) determined from 99 three-component recordings of ground motion generated by nuclear explosions in Nevada. The resulting empirical relation is: Intensity Increment = 0.27 +2.70 log (AHSA), and average intensity increments for the various geologic units are -0.29 for granite, 0.19 for Franciscan Formation, 0.64 for the Great Valley Sequence, 0.82 for Santa Clara Formation, 1.34 for alluvium, 2.43 for bay mud. The maximum intensity map predicted from these empirical relations delineates areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hazard fault.
Prediction of maximum earthquake intensities for the San Francisco Bay region
Energy Technology Data Exchange (ETDEWEB)
Borcherdt, R.D.; Gibbs, J.F.
1975-01-01
The intensity data for the California earthquake of Apr 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the empirical relation derived between 1906 intensities and distance perpendicular to the fault for 917 sites underlain by rocks of the Franciscan formation is intensity = 2.69 - 1.90 log (distance) (km). For sites on other geologic units, intensity increments, derived with respect to this empirical relation, correlate strongly with the average horizontal spectral amplifications (AHSA) determined from 99 three-component recordings of ground motion generated by nuclear explosions in Nevada. The resulting empirical relation is intensity increment = 0.27 + 2.70 log (AHSA), and average intensity increments for the various geologic units are -0.29 for granite, 0.19 for Franciscan formation, 0.64 for the Great Valley sequence, 0.82 for Santa Clara formation, 1.34 for alluvium, and 2.43 for bay mud. The maximum intensity map predicted from these empirical relations delineates areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hayward fault.
International Nuclear Information System (INIS)
Arslan, A.
1999-01-01
Purpose: To evaluate the consistency of fat in the high intensity signals of the normal neurohypophysis and to differentiate the high signal of posterior pituitary from that of dorsum sella. Sagittal SE T1-weighted images with frequency encoding in the horizontal direction were used in order to differentiate the high signal of posterior pituitary and dorsum sella by the vertically-oriented chemical shift artifact. Material and methods: The sellae of 46 normal volunteers were imaged with a commercially available fat suppression technique and SE sequences with frequency encoding in vertical (25 cases) and horizontal (21 cases) axes. Results: The high signal intensity was absent in 9% of the normal volunteers with no predilection to any specific age group. None of the cases with posterior pituitary high intensity signals showed suppression of the signal with fat suppression technique. A fat suppression technique was helpful in documenting the hyperintensity in 7% of normal volunteers. Nineteen of the 21 (90%) cases with high signal intensity were detected by routine SE T1-weighted images, whereas 18 of the 19 (95%) cases were detected by imaging with frequency encoding in the horizontal direction. Conclusion: The high signal does not indicate the presence of fat. Fat suppression technique and a horizontal direction of frequency encoding help in differentiating the high signal of the neurohypophysis from that of dorsum sella. (orig.)
Voorhies, Coerte V.; Conrad, Joy
1996-01-01
The geomagnetic spatial power spectrum R(sub n)(r) is the mean square magnetic induction represented by degree n spherical harmonic coefficients of the internal scalar potential averaged over the geocentric sphere of radius r. McLeod's Rule for the magnetic field generated by Earth's core geodynamo says that the expected core surface power spectrum (R(sub nc)(c)) is inversely proportional to (2n + 1) for 1 less than n less than or equal to N(sub E). McLeod's Rule is verified by locating Earth's core with main field models of Magsat data; the estimated core radius of 3485 kn is close to the seismologic value for c of 3480 km. McLeod's Rule and similar forms are then calibrated with the model values of R(sub n) for 3 less than or = n less than or = 12. Extrapolation to the degree 1 dipole predicts the expectation value of Earth's dipole moment to be about 5.89 x 10(exp 22) Am(exp 2)rms (74.5% of the 1980 value) and the expected geomagnetic intensity to be about 35.6 (mu)T rms at Earth's surface. Archeo- and paleomagnetic field intensity data show these and related predictions to be reasonably accurate. The probability distribution chi(exp 2) with 2n+1 degrees of freedom is assigned to (2n + 1)R(sub nc)/(R(sub nc). Extending this to the dipole implies that an exceptionally weak absolute dipole moment (less than or = 20% of the 1980 value) will exist during 2.5% of geologic time. The mean duration for such major geomagnetic dipole power excursions, one quarter of which feature durable axial dipole reversal, is estimated from the modern dipole power time-scale and the statistical model of excursions. The resulting mean excursion duration of 2767 years forces us to predict an average of 9.04 excursions per million years, 2.26 axial dipole reversals per million years, and a mean reversal duration of 5533 years. Paleomagnetic data show these predictions to be quite accurate. McLeod's Rule led to accurate predictions of Earth's core radius, mean paleomagnetic field
Flow of liquid metals in curved channels under a transversely applied magnetic field, (3)
International Nuclear Information System (INIS)
Arai, Shigeki; Tomita, Yukio; Sudou, Kouzou.
1979-01-01
With the development of electromagnetic pumps in nuclear, metallurgical and casting industries, investigations of not only laminar flow but also transient and turbulent flows in magnetohydrodynamic (MHD) channels are the matters of much concern. However, it is no exaggeration to say that there was no investigation of transient and turbulent flows in curved MHD channels. In this report, the influences of Reynolds number, Hartmann number, radius of curvature and aspect ratio on the coefficient of friction in transient and turbulent flow channels are discussed. In transient flow region, the curve representing the product of the coefficient of channel friction in curved channels and Reynolds number has no clear transition point in the flow of comparatively small Hartmann number. However, as the intensity of magnetic field is increased, the curve transfers to the transition due to the effect of suppressing secondary flow, and if the magnetic field is further increased, it was found that it approached the crisis-free type transition. In turbulent flow region, the coefficient of channel friction can be expressed approximately by the empirical equation given first in this report. Also the effect of magnetic field on the turbulent flow in curved channels can be explained by using Hartmann effect, turbulence suppression effect, and the effect of suppressing secondary flow based on Lorentz's force. (Wakatsuki, Y.)
Automated coronal hole identification via multi-thermal intensity segmentation
Garton, Tadhg M.; Gallagher, Peter T.; Murray, Sophie A.
2018-01-01
Coronal holes (CH) are regions of open magnetic fields that appear as dark areas in the solar corona due to their low density and temperature compared to the surrounding quiet corona. To date, accurate identification and segmentation of CHs has been a difficult task due to their comparable intensity to local quiet Sun regions. Current segmentation methods typically rely on the use of single Extreme Ultra-Violet passband and magnetogram images to extract CH information. Here, the coronal hole identification via multi-thermal emission recognition algorithm (CHIMERA) is described, which analyses multi-thermal images from the atmospheric image assembly (AIA) onboard the solar dynamics observatory (SDO) to segment coronal hole boundaries by their intensity ratio across three passbands (171 Å, 193 Å, and 211 Å). The algorithm allows accurate extraction of CH boundaries and many of their properties, such as area, position, latitudinal and longitudinal width, and magnetic polarity of segmented CHs. From these properties, a clear linear relationship was identified between the duration of geomagnetic storms and coronal hole areas. CHIMERA can therefore form the basis of more accurate forecasting of the start and duration of geomagnetic storms.
Intensive Monitoring Survey of Nearby Galaxies (IMSNG): Catching Early Light Curves of Supernovae
Im, Myungshin; IMSNG Team
2018-01-01
SNe light curves have been used to study the expansion history of the universe, and a lot of efforts have gone into understanding the overall shape of the radioactively powered light curve. However, we still have little direct observational evidence for the theorized SN progenitor systems. Recent studies suggest that the light curve of a supernova shortly after its explosion (world. Through this survey, we expect to catch the very early precursor emission as faint as R=21 mag (~0.1 Rsun for the progenitor). This poster outlines this project, and present a few scientific highlights, such as the early light curve of SN 2015F in NGC 2442.
Development of a statistically-based lower bound fracture toughness curve (Ksub(IR) curve)
International Nuclear Information System (INIS)
Wullaert, R.A.; Server, W.L.; Oldfield, W.; Stahlkopf, K.E.
1977-01-01
A program of initiation fracture toughness measurements on fifty heats of nuclear pressure vessel production materials (including weldments) was used to develop a methodology for establishing a revised reference toughness curve. The new methodology was statistically developed and provides a predefined confidence limit (or tolerance limit) for fracture toughness based upon many heats of a particular type of material. Overall reference curves were developed for seven specific materials using large specimen static and dynamic fracture toughness results. The heat-to-heat variation was removed by normalizing both the fracture toughness and temperature data with the precracked Charpy tanh curve coefficients for each particular heat. The variance and distribution about the curve were determined, and lower bounds of predetermined statistical significance were drawn based upon a Pearson distribution in the lower shelf region (since the data were skewed to high values) and a t-distribution in the transition temperature region (since the data were normally distributed)
International Nuclear Information System (INIS)
Kaiser, B; Brand, A; Glässl, M; Vagov, A; Axt, V M; Pietsch, U
2013-01-01
We analyze theoretically the high intensity photoionization dynamics of a system with two atomic states resonantly coupled by coherent extreme ultraviolet laser radiation that also gives rise to the ionization. The ground state occupation of such a system is shown to exhibit damped Rabi oscillations. The corresponding ionization, which is responsible for the damping, scales almost linearly with the field intensity when the pulse length exceeds the Rabi period. For shorter pulses a quadratic scaling is found. The Rabi frequency is shifted compared to its value for an isolated two-level system. The shift increases with excitation intensity and can acquire a high percentage of the unrenormalized frequency at high intensities. Analytical results obtained within a simplified solvable model demonstrate that the damping and the shift both result from the coupling of the discrete states to the ionization continuum and are therefore closely related. Numerical simulations for a two-electron system reveal at high intensities the importance of off-resonant ionization channels. (paper)
Stimulus-dependent modulation of spontaneous low-frequency oscillations in the rat visual cortex.
Huang, Liangming; Liu, Yadong; Gui, Jianjun; Li, Ming; Hu, Dewen
2014-08-06
Research on spontaneous low-frequency oscillations is important to reveal underlying regulatory mechanisms in the brain. The mechanism for the stimulus modulation of low-frequency oscillations is not known. Here, we used the intrinsic optical imaging technique to examine stimulus-modulated low-frequency oscillation signals in the rat visual cortex. The stimulation was presented monocularly as a flashing light with different frequencies and intensities. The phases of low-frequency oscillations in different regions tended to be synchronized and the rhythms typically accelerated within a 30-s period after stimulation. These phenomena were confined to visual stimuli with specific flashing frequencies (12.5-17.5 Hz) and intensities (5-10 mA). The acceleration and synchronization induced by the flashing frequency were more marked than those induced by the intensity. These results show that spontaneous low-frequency oscillations can be modulated by parameter-dependent flashing lights and indicate the potential utility of the visual stimulus paradigm in exploring the origin and function of low-frequency oscillations.
Castillo, Javier Malda; Jivraj, Stephen; Ng Fat, Linda
2017-01-01
Alcohol consumption frequency and volume are known to be related to health problems among drinkers. Most of the existing literature that analyses regional variation in drinking behaviour uses measures of consumption that relate only to volume, such as 'binge drinking'. This study compares the regional association of alcohol consumption using measures of drinking frequency (daily drinking) and volume (binge drinking) using a nationally representative sample of residents using the Health Survey for England, 2011-2013. Results suggest the presence of two differentiated drinking patterns with relevant policy implications. We find that people in northern regions are more likely to binge drink, whereas people in southern regions are more likely to drink on most days. Regression analysis shows that regional variation in binge drinking remains strong when taking into account individual and neighbourhood level controls. The findings provide support for regional targeting of interventions that aim to reduce the frequency as well as volume of drinking. Copyright © 2016 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Millar, B.C.; Millar, J.L.
1977-01-01
The biradical nitroxyl, Ro.03-6061, sensitized two lines of mouse L cell to ionizing radiation when the cells were rendered hypoxic. Although the biradical reduced the D 0 value of the hypoxic cell-survival curve in each instance, it had no significant effect on the shoulder region. A hybrid line produced from these two strains was more radioresistant than either parent. In this instance, the biradical suppressed the shoulder region of the hypoxic cell-survival curve, but had no effect on the D 0 value. In a second system, the biradical selectivity sensitized hypoxic cells of a diploid and a tetraploid clone of Syrian hamster cells (BHK21/C15). The survival-curve characteristics of both clones were similar. The biradical reduced the D 0 value but did not significantly change the shoulder region of the hypoxic cell-survival curve. An aneuploid line sub-cultured from the tetraploid clone was much more resistant to radiation. In this instance, there was a decrease in the D 0 value of hypoxic cells in the presence of the biradical, but the extrapolation number was increased to a value similar to that for cells irradiated in air. (author)
Directory of Open Access Journals (Sweden)
Nishihara K
2014-09-01
Full Text Available Ken Nishihara,1 Hisashi Kawai,2 Hiroyuki Hayashi,3 Hideo Naruse,4 Akihito Kimura,4 Toshiaki Gomi,5 Fumihiko Hoshi1 1Department of Physical Therapy, Saitama Prefectural University, Saitama, Japan; 2Health Promotion Management Office, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan; 3Center for University-wide Education, Saitama Prefectural University, Saitama, Japan; 4Faculty of Health Sciences, Tokyo Ariake University of Medical and Health Sciences, Tokyo, Japan, 5Faculty of Nursing, Tokyo Ariake University of Medical and Health Sciences, Tokyo, Japan Background: The skeletal muscle echo intensity (EI during ultrasound imaging has been investigated to evaluate the muscle quality. However, EI fluctuates according to the scanning conditions.Methods: The motor functions and ultrasound images of 19 elderly (73±3.2 years and 19 young (22±1.5 years individuals were investigated and an EI frequency component was assessed for more reliable evaluations. Healthy elderly and young subjects participated in this study. The motor functions were assessed during walking and according to the knee extension muscle strength. The muscle thicknesses of rectus femoris (RF, vastus intermedius (VI, and quadriceps femoris (QF were investigated. EIs were calculated and the mean frequencies of the regions of interest (MFROIs for RF and VI were analyzed. Results: EIs and MFROIs were greater in elderly subjects than in young subjects (P<0.01 for RF, and P<0.001 for VI, in EIs; and P<0.01 for RF, and P<0.05 for VI, in MFROIs. In young subjects, EI of RF was greater than that of VI; however, there was no difference between the RF and VI MFROIs in both elderly and young subjects. EIs of VI exhibited a significantly negative correlation with the QF thickness in both elderly and young subjects. RF MFROIs negatively correlated with the QF thickness and positively correlated with EI of VI in elderly subjects alone. Conclusion: These findings
Espil, Flint M.; Capriotti, Matthew R.; Conelea, Christine A.; Woods, Douglas W.
2014-01-01
Tic severity is composed of several dimensions. Tic frequency and intensity are two such dimensions, but little empirical data exist regarding their relative contributions to functional impairment in those with Chronic Tic Disorders (CTD). The present study examined the relative contributions of these dimensions in predicting tic-related impairment across several psychosocial domains. Using data collected from parents of youth with CTD, multivariate regression analyses revealed that both tic frequency and intensity predicted tic-related impairment in several areas; including family and peer relationships, school interference, and social endeavors, even when controlling for the presence of comorbid anxiety symptoms and Attention Deficit Hyperactivity Disorder diagnostic status. Results showed that tic intensity predicted more variance across more domains than tic frequency. PMID:24395287
Espil, Flint M; Capriotti, Matthew R; Conelea, Christine A; Woods, Douglas W
2014-12-01
Tic severity is composed of several dimensions. Tic frequency and intensity are two such dimensions, but little empirical data exist regarding their relative contributions to functional impairment in those with chronic tic disorders (CTD). The present study examined the relative contributions of these dimensions in predicting tic-related impairment across several psychosocial domains. Using data collected from parents of youth with CTD, multivariate regression analyses revealed that both tic frequency and intensity predicted tic-related impairment in several areas; including family and peer relationships, school interference, and social endeavors, even when controlling for the presence of comorbid anxiety symptoms and Attention Deficit Hyperactivity Disorder diagnostic status. Results showed that tic intensity predicted more variance across more domains than tic frequency.
Demissie, Y.; Mortuza, M. R.; Moges, E.; Yan, E.; Li, H. Y.
2017-12-01
Due to the lack of historical and future streamflow data for flood frequency analysis at or near most drainage sites, it is a common practice to directly estimate the design flood (maximum discharge or volume of stream for a given return period) based on storm frequency analysis and the resulted Intensity-Duration-Frequency (IDF) curves. Such analysis assumes a direct relationship between storms and floods with, for example, the 10-year rainfall expected to produce the 10-year flood. However, in reality, a storm is just one factor among the many other hydrological and metrological factors that can affect the peak flow and hydrograph. Consequently, a heavy storm does not necessarily always lead to flooding or a flood events with the same frequency. This is evident by the observed difference in the seasonality of heavy storms and floods in most regions. In order to understand site specific causal-effect relationship between heavy storms and floods and improve the flood analysis for stormwater drainage design and management, we have examined the contributions of various factors that affect floods using statistical and information theory methods. Based on the identified dominant causal-effect relationships, hydrologic and probability analyses were conducted to develop the runoff IDF curves taking into consideration the snowmelt and rain-on-snow effect, the difference in the storm and flood seasonality, soil moisture conditions, and catchment potential for flash and riverine flooding. The approach was demonstrated using data from military installations located in different parts of the United States. The accuracy of the flood frequency analysis and the resulted runoff IDF curves were evaluated based on the runoff IDF curves developed from streamflow measurements.
Diurnal variations of summer precipitation over the regions east to Tibetan Plateau
Wu, Yang; Huang, Anning; Huang, Danqing; Chen, Fei; Yang, Ben; Zhou, Yang; Fang, Dexian; Zhang, Lujun; Wen, Lijuan
2017-12-01
Based on the hourly gauge-satellite merged precipitation product with the horizontal resolution of 0.1° latitude/longitude during 2008-2014, diurnal variations of the summer precipitation amount (PA), frequency (PF), and intensity (PI) with different duration time over the regions east to Tibetan Plateau have been systematically revealed in this study. Results indicate that the eight typical precipitation diurnal patterns identified by the cluster analysis display pronounced regional features among the plateaus, basins, plains, hilly and coastal areas. The precipitation diurnal cycles are significantly affected by the sub-grid terrain fluctuations. The PA, PF and PI of the total rainfall show much more pronounced double diurnal peaks with the sub-grid topography standard deviation (SD) decreased. Meanwhile, the diurnal peaks of PA and PF (PI) strengthen (weaken) with the sub-grid topography SD enhanced. Over the elevated mountain ranges, southeastern hilly and coastal regions, the PA and PF diurnal patterns of the total rainfall generally show predominant late-afternoon peaks, which are closely associated with the short-duration (≤slant 3 h) rainfall. Along the Tibetan Plateau to its downstream, the diurnal peaks of PA, PF and PI for the total rainfall all exhibit obvious eastward phase time delay mainly due to the diurnal evolutions of long-duration (> 6 h) rainfall. However, the 4-6 h rainfall leads to the eastward phase time delay of the total rainfall along the Taihang Mountains to its downstream. Further mechanism analysis suggests that the midnight to morning diurnal evolution of the long-duration rainfall is closely associated with the diurnal variations of the upward branches of thermally driven mountain-plain solenoids and the water vapor transport associated with the accelerated nocturnal southwesterly winds. The late-afternoon peak of the short-duration PA over the southeastern hilly and coastal regions is ascribed to the strong local thermal
Kugler, Kathrin; Wiegrebe, Lutz; Gürkov, Robert; Krause, Eike; Drexl, Markus
2015-12-01
>Human hearing is rather insensitive for very low frequencies (i.e. below 100 Hz). Despite this insensitivity, low-frequency sound can cause oscillating changes of cochlear gain in inner ear regions processing even much higher frequencies. These alterations outlast the duration of the low-frequency stimulation by several minutes, for which the term 'bounce phenomenon' has been coined. Previously, we have shown that the bounce can be traced by monitoring frequency and level changes of spontaneous otoacoustic emissions (SOAEs) over time. It has been suggested elsewhere that large receptor potentials elicited by low-frequency stimulation produce a net Ca(2+) influx and associated gain decrease in outer hair cells. The bounce presumably reflects an underdamped, homeostatic readjustment of increased Ca(2+) concentrations and related gain changes after low-frequency sound offset. Here, we test this hypothesis by activating the medial olivocochlear efferent system during presentation of the bounce-evoking low-frequency (LF) sound. The efferent system is known to modulate outer hair cell Ca(2+) concentrations and receptor potentials, and therefore, it should modulate the characteristics of the bounce phenomenon. We show that simultaneous presentation of contralateral broadband noise (100 Hz-8 kHz, 65 and 70 dB SPL, 90 s, activating the efferent system) and ipsilateral low-frequency sound (30 Hz, 120 dB SPL, 90 s, inducing the bounce) affects the characteristics of bouncing SOAEs recorded after low-frequency sound offset. Specifically, the decay time constant of the SOAE level changes is shorter, and the transient SOAE suppression is less pronounced. Moreover, the number of new, transient SOAEs as they are seen during the bounce, are reduced. Taken together, activation of the medial olivocochlear system during induction of the bounce phenomenon with low-frequency sound results in changed characteristics of the bounce phenomenon. Thus, our data provide experimental support
Regional price differences and food consumption frequency among elementary school children.
Sturm, R; Datar, A
2011-03-01
Food prices may affect diet and weight gain among youth and lead to geographic disparities in obesity. This paper examines the association between regional prices and consumption frequency of fruit/vegetables and snack items among elementary school children in the USA. Observational study using individual-level survey data of fifth-grade children (average age 11 years) and regional food prices based on store visits in 2004. Dependent variables are self-reported consumption frequency in fifth grade; primary explanatory variables are metropolitan area food prices relative to cost of living. Multivariate regression analysis. Price variation across metropolitan areas exists, and lower real prices for vegetables and fruits predict significantly higher intake frequency. Higher dairy prices predict lower frequency of milk consumption, while higher meat prices predict increased milk consumption. Similar price effects were not found for fast food or soft drink consumption. The geographic variation in food prices across the USA is sufficiently large to affect dietary patterns among youth for fruit, vegetables and milk. The price variation is either too small to affect children's consumption frequency of fast food or soft drinks, or the consumption of these foods is less price sensitive. Copyright © 2010 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.