WorldWideScience

Sample records for time scale radiological

  1. International scaling of nuclear and radiological events

    International Nuclear Information System (INIS)

    Wang Yuhui; Wang Haidan

    2014-01-01

    Scales are inherent forms of measurement used in daily life, just like Celsius or Fahrenheit scales for temperature and Richter for scale for earthquakes. Jointly developed by the IAEA and OECD/NEA in 1990, the purpose of International Nuclear and Radiological Event Scale (INES) is to help nuclear and radiation safety authorities and the nuclear industry worldwide to rate nuclear and radiological events and to communicate their safety significance to the general public, the media and the technical community. INES was initially used to classify events at nuclear power plants only. It was subsequently extended to rate events associated with the transport, storage and use of radioactive material and radiation sources, from those occurring at nuclear facilities to those associated with industrial use. Since its inception, it has been adopted in 69 countries. Events are classified on the scale at seven levels: Levels 1-3 are called 'incidents' and Levels 4-7 'accidents'. The scale is designed so that the severity of an event is about ten times greater for each increase in level on the scale. Events without safety significance are called 'deviations' and are classified Below Scale/Level 0. INES classifies nuclear and radiological accidents and incidents by considering three areas of impact: People and the Environment; Radiological Barriers and Control; Defence-in-Depth. By now, two nuclear accidents were on the highest level of the scale: Chernobyl and Fukumashi. (authors)

  2. RSVP radiology

    International Nuclear Information System (INIS)

    Kirks, D.R.; Chaffee, D.J.

    1990-01-01

    This paper develops a relative scale of value for pediatric radiology (RSVPR). Neither the HCFA/ACA Relative Value Scale nor the Workload Measurement System developed by Health and Welfare Canada specifically addressed pediatric radiologic examinations. Technical and professional charges for examinations at Children's Hospital Medical Center were reviewed and compared with time and cost analysis. A scale was developed with chest radiography (PA and lateral views) assigned a value of 1. After review by pediatric radiologic technologists, radiologic administrators, pediatric radiologists, and chairs of departments of children's hospitals, this proposed scale was modified to reflect more accurately relative value components of pediatric radiologic and imaging examinations

  3. Ensemble Pulsar Time Scale

    Science.gov (United States)

    Yin, Dong-shan; Gao, Yu-ping; Zhao, Shu-hong

    2017-07-01

    Millisecond pulsars can generate another type of time scale that is totally independent of the atomic time scale, because the physical mechanisms of the pulsar time scale and the atomic time scale are quite different from each other. Usually the pulsar timing observations are not evenly sampled, and the internals between two data points range from several hours to more than half a month. Further more, these data sets are sparse. All this makes it difficult to generate an ensemble pulsar time scale. Hence, a new algorithm to calculate the ensemble pulsar time scale is proposed. Firstly, a cubic spline interpolation is used to densify the data set, and make the intervals between data points uniform. Then, the Vondrak filter is employed to smooth the data set, and get rid of the high-frequency noises, and finally the weighted average method is adopted to generate the ensemble pulsar time scale. The newly released NANOGRAV (North American Nanohertz Observatory for Gravitational Waves) 9-year data set is used to generate the ensemble pulsar time scale. This data set includes the 9-year observational data of 37 millisecond pulsars observed by the 100-meter Green Bank telescope and the 305-meter Arecibo telescope. It is found that the algorithm used in this paper can reduce effectively the influence caused by the noises in pulsar timing residuals, and improve the long-term stability of the ensemble pulsar time scale. Results indicate that the long-term (> 1 yr) stability of the ensemble pulsar time scale is better than 3.4 × 10-15.

  4. Subspecialized Radiological Reporting Expedites Turnaround Time of Radiology Reports and Increases Productivity.

    Science.gov (United States)

    Stern, Christoph; Boehm, Thomas; Seifert, Burkhardt; Kawel-Boehm, Nadine

    2018-02-15

     To assess the impact of changing from general to subspecialized reporting on turnaround time of radiology reports (TAT), the fraction of radiology reports available within 24 hours (RReporting workflow in our radiology department was changed from general reporting (radiologists report imaging studies of all areas [neuroradiological, abdominal, musculoskeletal imaging et cetera]) to subspecialized reporting (radiologists solely report imaging studies of their subspecialty field [e. g. musculoskeletal]). TAT, Rreporting (January-December 2012) and compared to a 12-month period of subspecialized reporting (April 2014-March 2015) using Mann Whitney U-test, Pearson chi-square test and odds ratios, respectively.  Report TAT decreased from a median of 17:04 hours (h) during general reporting to 3:38 h during subspecialized reporting, resulting in a 4.7-fold improvement (p report being available reporting. Productivity increased from a median of 301 to 376 (reports/full-time radiologist/month) (p = 0.001).  Changing the workflow from general to subspecialized reporting significantly improved the turnaround time of radiology reports, the fraction of radiology reports available within 24 hours and productivity.   · Changing the radiology reporting workflow from general to subspecialized reporting is feasible.. · Implementation of subspecialized reporting yielded significant improvement of radiology report turnaround time.. · Implementation of subspecialized reporting substantially increased the fraction of radiology reports available reporting.. · Stern C, Boehm T, Seifert B et al. Subspecialized Radiological Reporting Expedites Turnaround Time of Radiology Reports and Increases Productivity. Fortschr Röntgenstr 2018; DOI: 10.1055/s-0044-100728. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Computerized Monitoring and Analysis of Radiology Report Turnaround Times

    Science.gov (United States)

    Wang, Yen

    1989-05-01

    A computerized Radiology Management System was used to monitor the turnaround time of radiology reports in a large university hospital. The time from patient entry into the department until the printing and distribution of the final examination report was monitored periodically for two-week time intervals. Total turnaround time was divided into four separate components. Analysis of the data enabled us to assess individual and departmental performance and thereby improve important patient service functions.

  6. Proposed classification scale for radiological incidents and accidents

    International Nuclear Information System (INIS)

    2003-04-01

    The scale proposed in this report is intended to facilitate communication concerning the severity of incidents and accidents involving the exposure of human beings to ionising radiations. Like the INES, it comprises eight levels of severity and uses the same terms (accident, incident, anomaly, serious and major) for keeping the public and the media informed. In a radiological protection context, the severity of an event is considered as being directly proportional to the risk run by an individual (the probability of developing fatal or non-fatal health effects) following exposure to ionising radiation in an incident or accident situation. However for society, other factors have to be taken into account to determine severity. The severity scale proposed is therefore based on assessment of the individual radiological risk. A severity level corresponding to exposure of a member of the public in an incident or accident situation is determined on the basis of risk assessment concepts and methods derived from international consensus on dose/effect relationships for both stochastic and deterministic effects. The severity of all the possible exposure situations - worker exposure, collective exposure, potential exposure - is determined using a system of weighting in relation to situations involving members of the public. In the case of this scale, to indicate the severity of an event, it is proposed to make use of the most penalizing level of severity, comparing: - the severity associated with the probability of occurrence of deterministic effects and the severity associated with the probability of occurrence of stochastic effects, when the event gives rise to both types of risk; - the severity for members of the public and the severity for exposed workers, when both categories of individuals are involved; - the severity on the proposed radiological protection scale and that obtained using the INES, when radiological protection and nuclear safety aspects are associated with

  7. Multiple time scale dynamics

    CERN Document Server

    Kuehn, Christian

    2015-01-01

    This book provides an introduction to dynamical systems with multiple time scales. The approach it takes is to provide an overview of key areas, particularly topics that are less available in the introductory form.  The broad range of topics included makes it accessible for students and researchers new to the field to gain a quick and thorough overview. The first of its kind, this book merges a wide variety of different mathematical techniques into a more unified framework. The book is highly illustrated with many examples and exercises and an extensive bibliography. The target audience of this  book are senior undergraduates, graduate students as well as researchers interested in using the multiple time scale dynamics theory in nonlinear science, either from a theoretical or a mathematical modeling perspective. 

  8. Radiology

    International Nuclear Information System (INIS)

    Edholm, P.R.

    1990-01-01

    This is a report describing diagnostic techniques used in radiology. It describes the equipment necessary for, and the operation of a radiological department. Also is described the standard methods used in radiodiagnosis. (K.A.E.)

  9. Radiology

    International Nuclear Information System (INIS)

    Sykora, A.

    2006-01-01

    In this text-book basic knowledge about radiology, biomedical diagnostic methods (radiography, computer tomography), nuclear medicine and safety and radiation protection of personnel on the radiodiagnostic place of work are presented

  10. Dynamic inequalities on time scales

    CERN Document Server

    Agarwal, Ravi; Saker, Samir

    2014-01-01

    This is a monograph devoted to recent research and results on dynamic inequalities on time scales. The study of dynamic inequalities on time scales has been covered extensively in the literature in recent years and has now become a major sub-field in pure and applied mathematics. In particular, this book will cover recent results on integral inequalities, including Young's inequality, Jensen's inequality, Holder's inequality, Minkowski's inequality, Steffensen's inequality, Hermite-Hadamard inequality and Čebyšv's inequality. Opial type inequalities on time scales and their extensions with weighted functions, Lyapunov type inequalities, Halanay type inequalities for dynamic equations on time scales, and Wirtinger type inequalities on time scales and their extensions will also be discussed here in detail.

  11. A presentation system for just-in-time learning in radiology.

    Science.gov (United States)

    Kahn, Charles E; Santos, Amadeu; Thao, Cheng; Rock, Jayson J; Nagy, Paul G; Ehlers, Kevin C

    2007-03-01

    There is growing interest in bringing medical educational materials to the point of care. We sought to develop a system for just-in-time learning in radiology. A database of 34 learning modules was derived from previously published journal articles. Learning objectives were specified for each module, and multiple-choice test items were created. A web-based system-called TEMPO-was developed to allow radiologists to select and view the learning modules. Web services were used to exchange clinical context information between TEMPO and the simulated radiology work station. Preliminary evaluation was conducted using the System Usability Scale (SUS) questionnaire. TEMPO identified learning modules that were relevant to the age, sex, imaging modality, and body part or organ system of the patient being viewed by the radiologist on the simulated clinical work station. Users expressed a high degree of satisfaction with the system's design and user interface. TEMPO enables just-in-time learning in radiology, and can be extended to create a fully functional learning management system for point-of-care learning in radiology.

  12. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  13. 24/7 pediatric radiology attending coverage: times are changing

    Energy Technology Data Exchange (ETDEWEB)

    Donaldson, James S. [Feinberg School of Medicine at Northwestern University, Department of Medical Imaging, Ann and Robert H. Lurie Children' s Hospital of Chicago, IL (United States); Thakrar, Kiran H. [University of Chicago Pritzker School of Medicine, Body Imaging, NorthShore University HealthSystem, Chicago, IL (United States)

    2017-06-15

    The job of the pediatric radiologist long ago ceased to be an 8-to-5 role. Many practices have adopted evening shifts of in-house attending radiologists to cover the busy evening activity. With the ever-increasing role of imaging in clinical decisions and patient management, there is a need - if not a demand - to further extend attending pediatric radiology coverage. In this article, we discuss the needs and justification for extending pediatric radiology coverage at a tertiary-care children's hospital. We also describe the approach we took toward implementing 24/7 attending in-house coverage of pediatric radiology. (orig.)

  14. A laboratory scale fundamental time?

    International Nuclear Information System (INIS)

    Mendes, R.V.

    2012-01-01

    The existence of a fundamental time (or fundamental length) has been conjectured in many contexts. However, the ''stability of physical theories principle'' seems to be the one that provides, through the tools of algebraic deformation theory, an unambiguous derivation of the stable structures that Nature might have chosen for its algebraic framework. It is well-known that c and ℎ are the deformation parameters that stabilize the Galilean and the Poisson algebra. When the stability principle is applied to the Poincare-Heisenberg algebra, two deformation parameters emerge which define two time (or length) scales. In addition there are, for each of them, a plus or minus sign possibility in the relevant commutators. One of the deformation length scales, related to non-commutativity of momenta, is probably related to the Planck length scale but the other might be much larger and already detectable in laboratory experiments. In this paper, this is used as a working hypothesis to look for physical effects that might settle this question. Phase-space modifications, resonances, interference, electron spin resonance and non-commutative QED are considered. (orig.)

  15. Time Is Not on Our Side: How Radiology Practices Should Manage Customer Queues.

    Science.gov (United States)

    Loving, Vilert A; Ellis, Richard L; Rippee, Robert; Steele, Joseph R; Schomer, Donald F; Shoemaker, Stowe

    2017-11-01

    As health care shifts toward patient-centered care, wait times have received increasing scrutiny as an important metric for patient satisfaction. Long queues form when radiology practices inefficiently service their customers, leading to customer dissatisfaction and a lower perception of value. This article describes a four-step framework for radiology practices to resolve problematic queues: (1) analyze factors contributing to queue formation; (2) improve processes to reduce service times; (3) reduce variability; (4) address the psychology of queues. Copyright © 2017 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  16. Potential time savings to radiology department personnel in a PACS-based environment

    Science.gov (United States)

    Saarinen, Allan O.; Wilson, M. C.; Iverson, Scott C.; Loop, John W.

    1990-08-01

    A purported benefit of digital imaging and archiving of radiographic procedures is the presumption of time savings to radiologists, radiology technologists, and radiology departmentpersonnel involved with processingfilms and managing theflimfile room. As part of the University of Washington's evaluation of Picture Archiving and Communication Systems (PACS)for the U.S. Army Medical Research and Development Command, a study was performed which evaluated the current operationalpractices of the film-based radiology department at the University of Washington Medical Center (UWMC). Industrial engineering time and motion studies were conducted to document the length of time requiredforfilm processing in various modalities, the proportion of the total exam time usedforfilm processing, the amount of time radiologists spent searchingfor and looking at images, and the amount of time file room personnel spent collating reports, making loans, updatingfilm jacket information, and purging files. This evaluation showed that better than one-half of the tasks in the file room may be eliminated with PACS and radiologists may save easily 10 percent of the time they spend reading films by no longer having to searchforfilms. Radiology technologists may also save as much as 10 percent of their time with PACS, although this estimate is subject to significant patient mix aberrations and measurement error. Given that the UWMC radiology department operates efficiently, similar improvements are forecast for other radiology departments and larger improvements areforecastfor less efficient departments.

  17. The International Nuclear and Radiological Event Scale (INES): 20 Years of Nuclear Communication

    International Nuclear Information System (INIS)

    2010-01-01

    Full text: Today, the International Atomic Energy Agency (IAEA) and the OECD Nuclear Energy Agency (NEA) are celebrating the 20th anniversary of the International Nuclear and Radiological Event Scale (INES). Jointly developed by the IAEA and the NEA in 1990, in the aftermath of the Chernobyl accident, the purpose of INES is to help nuclear and radiation safety authorities and the nuclear industry worldwide to rate nuclear and radiological events and to communicate their safety significance to the general public, the media and the technical community. INES has often been compared to other scales used to measure physical properties such as temperature - the Celsius, Kelvin or Fahrenheit scales - or rate events such as earthquakes - the Richter scale. Like these scales, INES also has a sound technical background and can be easily understood. INES was initially used to classify events at nuclear power plants only. It was subsequently extended to rate events occurring in any nuclear facility and during the transport of radioactive material, thus also covering events related to the overexposure of workers. Since 2008, INES has been extended to any event associated with the transport, storage and use of radioactive material and radiation sources, from those occurring at nuclear facilities to those associated with industrial use. More generally, INES has also become a crucial nuclear communications tool. Since its inception, it has been adopted in 69 countries, and an increasing number of countries have expressed their interest in using INES and have designated INES national officers. Over the years, national nuclear safety authorities have made growing use of INES, while the public and the media have become more familiar with the scale and its significance. This is where the true success of INES stands, having helped to foster transparency and provide a better understanding of nuclear-related events and activities. For a full description of the International Nuclear and

  18. Novel real-time 3D radiological mapping solution for ALARA maximization, D and D assessments and radiological management

    Energy Technology Data Exchange (ETDEWEB)

    Dubart, Philippe; Hautot, Felix [AREVA Group, 1 route de la Noue, Gif sur Yvette (France); Morichi, Massimo; Abou-Khalil, Roger [AREVA Group, Tour AREVA-1, place Jean Millier, Paris (France)

    2015-07-01

    Good management of dismantling and decontamination (D and D) operations and activities is requiring safety, time saving and perfect radiological knowledge of the contaminated environment as well as optimization for personnel dose and minimization of waste volume. In the same time, Fukushima accident has imposed a stretch to the nuclear measurement operational approach requiring in such emergency situation: fast deployment and intervention, quick analysis and fast scenario definition. AREVA, as return of experience from his activities carried out at Fukushima and D and D sites has developed a novel multi-sensor solution as part of his D and D research, approach and method, a system with real-time 3D photo-realistic spatial radiation distribution cartography of contaminated premises. The system may be hand-held or mounted on a mobile device (robot, drone, e.g). In this paper, we will present our current development based on a SLAM technology (Simultaneous Localization And Mapping) and integrated sensors and detectors allowing simultaneous topographic and radiological (dose rate and/or spectroscopy) data acquisitions. This enabling technology permits 3D gamma activity cartography in real-time. (authors)

  19. Novel real-time 3D radiological mapping solution for ALARA maximization, D and D assessments and radiological management

    International Nuclear Information System (INIS)

    Dubart, Philippe; Hautot, Felix; Morichi, Massimo; Abou-Khalil, Roger

    2015-01-01

    Good management of dismantling and decontamination (D and D) operations and activities is requiring safety, time saving and perfect radiological knowledge of the contaminated environment as well as optimization for personnel dose and minimization of waste volume. In the same time, Fukushima accident has imposed a stretch to the nuclear measurement operational approach requiring in such emergency situation: fast deployment and intervention, quick analysis and fast scenario definition. AREVA, as return of experience from his activities carried out at Fukushima and D and D sites has developed a novel multi-sensor solution as part of his D and D research, approach and method, a system with real-time 3D photo-realistic spatial radiation distribution cartography of contaminated premises. The system may be hand-held or mounted on a mobile device (robot, drone, e.g). In this paper, we will present our current development based on a SLAM technology (Simultaneous Localization And Mapping) and integrated sensors and detectors allowing simultaneous topographic and radiological (dose rate and/or spectroscopy) data acquisitions. This enabling technology permits 3D gamma activity cartography in real-time. (authors)

  20. Real-Time Electronic Dashboard Technology and Its Use to Improve Pediatric Radiology Workflow.

    Science.gov (United States)

    Shailam, Randheer; Botwin, Ariel; Stout, Markus; Gee, Michael S

    The purpose of our study was to create a real-time electronic dashboard in the pediatric radiology reading room providing a visual display of updated information regarding scheduled and in-progress radiology examinations that could help radiologists to improve clinical workflow and efficiency. To accomplish this, a script was set up to automatically send real-time HL7 messages from the radiology information system (Epic Systems, Verona, WI) to an Iguana Interface engine, with relevant data regarding examinations stored in an SQL Server database for visual display on the dashboard. Implementation of an electronic dashboard in the reading room of a pediatric radiology academic practice has led to several improvements in clinical workflow, including decreasing the time interval for radiologist protocol entry for computed tomography or magnetic resonance imaging examinations as well as fewer telephone calls related to unprotocoled examinations. Other advantages include enhanced ability of radiologists to anticipate and attend to examinations requiring radiologist monitoring or scanning, as well as to work with technologists and operations managers to optimize scheduling in radiology resources. We foresee increased utilization of electronic dashboard technology in the future as a method to improve radiology workflow and quality of patient care. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Comparison of time-oriented cost accounting catalogs to control a Departement of Radiology

    International Nuclear Information System (INIS)

    Hacklaender, T.; Mertens, H.; Cramer, B.M.

    2005-01-01

    Purpose: Within a hospital, the radiology department has taken over the role of a cost center. Cost accounting can be applied to analyze the cost for the performance of services. By assigning the expenditures of resources to the service, the cash value can directly be distributed to the costs of equipment, material and rooms. Time-oriented catalogs of services are predefined to calculate the number of the employees for a radiology department. Using our own survey of time data, we examined whether such catalogs correctly represent the time consumed in a radiology department. Only services relevant for the turnover were compared. Materials and Methods: For 96 primary radiological services defined by the score-oriented German fee catalog for physicians (Gebuehrenordnung fuer Aerzte), a ranking list was made for the annual procedures in descending frequency order. According to the Pareto principle, the 11 services with the highest frequency were chosen and the time consumed for the technical and medical services was collected over a period of 2 months. This survey was compared with the time-oriented catalogs TARMED and EBM 2000plus. Results: The included 11 relevant radiological services represented 80.3% of the annual procedures of our radiology department. When comparing the technical services between the time-oriented catalogs and our own survey, TARMED gives a better description of the time consumed in 7 of the 11 services and EMB 2000plus in 3 services. When comparing the medical services, TARMED gives a better description of the time consumed in 6 of the 11 services and EBM 2000plus in 4 services. When averaging all the radiological services, TARMED overestimates the current number of physicians necessary for primary reading by a factor of 10.0% and EBM 2000plus by a factor of 2.6%. Conclusion: As to the time spent on performing the relevant radiological services. TARMED is slightly superior to describe the radiology department of a hospital than EBM 2000plus

  2. Applying Systems Engineering Reduces Radiology Transport Cycle Times in the Emergency Department

    Science.gov (United States)

    White, Benjamin A.; Yun, Brian J.; Lev, Michael H.; Raja, Ali S.

    2017-01-01

    Introduction Emergency department (ED) crowding is widespread, and can result in care delays, medical errors, increased costs, and decreased patient satisfaction. Simultaneously, while capacity constraints on EDs are worsening, contributing factors such as patient volume and inpatient bed capacity are often outside the influence of ED administrators. Therefore, systems engineering approaches that improve throughput and reduce waste may hold the most readily available gains. Decreasing radiology turnaround times improves ED patient throughput and decreases patient waiting time. We sought to investigate the impact of systems engineering science targeting ED radiology transport delays and determine the most effective techniques. Methods This prospective, before-and-after analysis of radiology process flow improvements in an academic hospital ED was exempt from institutional review board review as a quality improvement initiative. We hypothesized that reorganization of radiology transport would improve radiology cycle time and reduce waste. The intervention included systems engineering science-based reorganization of ED radiology transport processes, largely using Lean methodologies, and adding no resources. The primary outcome was average transport time between study order and complete time. All patients presenting between 8/2013–3/2016 and requiring plain film imaging were included. We analyzed electronic medical record data using Microsoft Excel and SAS version 9.4, and we used a two-sample t-test to compare data from the pre- and post-intervention periods. Results Following the intervention, average transport time decreased significantly and sustainably. Average radiology transport time was 28.7 ± 4.2 minutes during the three months pre-intervention. It was reduced by 15% in the first three months (4.4 minutes [95% confidence interval [CI] 1.5–7.3]; to 24.3 ± 3.3 min, P=0.021), 19% in the following six months (5.4 minutes, 95% CI [2.7–8.2]; to 23.3 ± 3

  3. Applying Systems Engineering Reduces Radiology Transport Cycle Times in the Emergency Department.

    Science.gov (United States)

    White, Benjamin A; Yun, Brian J; Lev, Michael H; Raja, Ali S

    2017-04-01

    Emergency department (ED) crowding is widespread, and can result in care delays, medical errors, increased costs, and decreased patient satisfaction. Simultaneously, while capacity constraints on EDs are worsening, contributing factors such as patient volume and inpatient bed capacity are often outside the influence of ED administrators. Therefore, systems engineering approaches that improve throughput and reduce waste may hold the most readily available gains. Decreasing radiology turnaround times improves ED patient throughput and decreases patient waiting time. We sought to investigate the impact of systems engineering science targeting ED radiology transport delays and determine the most effective techniques. This prospective, before-and-after analysis of radiology process flow improvements in an academic hospital ED was exempt from institutional review board review as a quality improvement initiative. We hypothesized that reorganization of radiology transport would improve radiology cycle time and reduce waste. The intervention included systems engineering science-based reorganization of ED radiology transport processes, largely using Lean methodologies, and adding no resources. The primary outcome was average transport time between study order and complete time. All patients presenting between 8/2013-3/2016 and requiring plain film imaging were included. We analyzed electronic medical record data using Microsoft Excel and SAS version 9.4, and we used a two-sample t-test to compare data from the pre- and post-intervention periods. Following the intervention, average transport time decreased significantly and sustainably. Average radiology transport time was 28.7 ± 4.2 minutes during the three months pre-intervention. It was reduced by 15% in the first three months (4.4 minutes [95% confidence interval [CI] 1.5-7.3]; to 24.3 ± 3.3 min, P=0.021), 19% in the following six months (5.4 minutes, 95% CI [2.7-8.2]; to 23.3 ± 3.5 min, P=0.003), and 26% one year

  4. INES: The International Nuclear and Radiological Event Scale User's Manual. 2008 Edition (Spanish Edition)

    International Nuclear Information System (INIS)

    2010-11-01

    INES, the International Nuclear and Radiological Event Scale, was developed in 1990 by experts convened by the IAEA and the OECD Nuclear Energy Agency with the aim of communicating the safety significance of events. This edition of the INES User?s Manual is designed to facilitate the task of those who are required to rate the safety significance of events using the scale. It includes additional guidance and clarifications, and provides examples and comments on the continued use of INES. With this new edition, it is anticipated that INES will be widely used by Member States and become the worldwide scale for putting into proper perspective the safety significance of any event associated with the transport, storage and use of radioactive material and radiation sources, whether or not the event occurs at a facility.

  5. INES: The International Nuclear and Radiological Event Scale User's Manual. 2008 Edition (Chinese Edition)

    International Nuclear Information System (INIS)

    2012-01-01

    INES, the International Nuclear and Radiological Event Scale, was developed in 1990 by experts convened by the IAEA and the OECD Nuclear Energy Agency with the aim of communicating the safety significance of events. This edition of the INES User's Manual is designed to facilitate the task of those who are required to rate the safety significance of events using the scale. It includes additional guidance and clarifications, and provides examples and comments on the continued use of INES. With this new edition, it is anticipated that INES will be widely used by Member States and become the worldwide scale for putting into proper perspective the safety significance of any event associated with the transport, storage and use of radioactive material and radiation sources, whether or not the event occurs at a facility.

  6. INES: The International Nuclear and Radiological Event Scale User's Manual. 2008 Edition (French Edition)

    International Nuclear Information System (INIS)

    2011-01-01

    INES, the International Nuclear and Radiological Event Scale, was developed in 1990 by experts convened by the IAEA and the OECD Nuclear Energy Agency with the aim of communicating the safety significance of events. This edition of the INES User?s Manual is designed to facilitate the task of those who are required to rate the safety significance of events using the scale. It includes additional guidance and clarifications, and provides examples and comments on the continued use of INES. With this new edition, it is anticipated that INES will be widely used by Member States and become the worldwide scale for putting into proper perspective the safety significance of any event associated with the transport, storage and use of radioactive material and radiation sources, whether or not the event occurs at a facility.

  7. Estimates of expansion time scales

    International Nuclear Information System (INIS)

    Jones, E.M.

    1979-01-01

    Monte Carlo simulations of the expansion of a spacefaring civilization show that descendants of that civilization should be found near virtually every useful star in the Galaxy in a time much less than the current age of the Galaxy. Only extreme assumptions about local population growth rates, emigration rates, or ship ranges can slow or halt an expansion. The apparent absence of extraterrestrials from the solar system suggests that no such civilization has arisen in the Galaxy. 1 figure

  8. Stochastic time scale for the Universe

    International Nuclear Information System (INIS)

    Szydlowski, M.; Golda, Z.

    1986-01-01

    An intrinsic time scale is naturally defined within stochastic gradient dynamical systems. It should be interpreted as a ''relaxation time'' to a local potential minimum after the system has been randomly perturbed. It is shown that for a flat Friedman-like cosmological model this time scale is of order of the age of the Universe. 7 refs. (author)

  9. Time scale in quasifission reactions

    Energy Technology Data Exchange (ETDEWEB)

    Back, B.B.; Paul, P.; Nestler, J. [and others

    1995-08-01

    The quasifission process arises from the hindrance of the complete fusion process when heavy-ion beams are used. The strong dissipation in the system tends to prevent fusion and lead the system towards reseparation into two final products of similar mass reminiscent of a fission process. This dissipation slows down the mass transfer and shape transformation and allows for the emission of high energy {gamma}-rays during the process, albeit with a low probability. Giant Dipole {gamma} rays emitted during this time have a characteristic spectral shape and may thus be discerned in the presence of a background of {gamma} rays emitted from the final fission-like fragments. Since the rate of GDR {gamma} emission is very well established, the strength of this component may therefore be used to measure the timescale of the quasifission process. In this experiment we studied the reaction between 368-MeV {sup 58}Ni and a {sup 165}Ho target, where deep inelastic scattering and quasifission processes are dominant. Coincidences between fission fragments (detected in four position-sensitive avalanche detectors) and high energy {gamma} rays (measured in a 10{close_quotes} x 10{close_quotes} actively shielded NaI detector) were registered. Beams were provided by the Stony Brook Superconducting Linac. The {gamma}-ray spectrum associated with deep inelastic scattering events is well reproduced by statistical cooling of projectile and target-like fragments with close to equal initial excitation energy sharing. The y spectrum associated with quasifission events is well described by statistical emission from the fission fragments alone, with only weak evidence for GDR emission from the mono-nucleus. A 1{sigma} limit of t{sub ss} < 11 x 10{sup -21} s is obtained for the mono-nucleus lifetime, which is consistent with the lifetime obtained from quasifission fragment angular distributions. A manuscript was accepted for publication.

  10. Intervention of the army health service in the case of radiological accident in peace time

    International Nuclear Information System (INIS)

    Curet, P.M.; Croq, M.

    2001-01-01

    The Army Health Service has conceived an organisation and has at its disposal the means necessary to answer the consequences of an accident having a radiological type in peace time in the military field. Its intervention area can be extended to the civil medium at the public authorities demand to give assistance. (N.C.)

  11. Multiple time scale methods in tokamak magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jardin, S.C.

    1984-01-01

    Several methods are discussed for integrating the magnetohydrodynamic (MHD) equations in tokamak systems on other than the fastest time scale. The dynamical grid method for simulating ideal MHD instabilities utilizes a natural nonorthogonal time-dependent coordinate transformation based on the magnetic field lines. The coordinate transformation is chosen to be free of the fast time scale motion itself, and to yield a relatively simple scalar equation for the total pressure, P = p + B/sup 2//2..mu../sub 0/, which can be integrated implicitly to average over the fast time scale oscillations. Two methods are described for the resistive time scale. The zero-mass method uses a reduced set of two-fluid transport equations obtained by expanding in the inverse magnetic Reynolds number, and in the small ratio of perpendicular to parallel mobilities and thermal conductivities. The momentum equation becomes a constraint equation that forces the pressure and magnetic fields and currents to remain in force balance equilibrium as they evolve. The large mass method artificially scales up the ion mass and viscosity, thereby reducing the severe time scale disparity between wavelike and diffusionlike phenomena, but not changing the resistive time scale behavior. Other methods addressing the intermediate time scales are discussed.

  12. Radiological assessment of petroleum pipe scale waste streams from dry rattling operations - 16323

    International Nuclear Information System (INIS)

    Hamilton, Ian S.; Arno, Matthew G.; Fruchtnicht, Erich H.; Berry, Robert O.

    2009-01-01

    Petroleum pipe scale consists of inorganic solids, such as barium sulfate. These solids can precipitate out of brine solutions that are pumped out of oil wells as part of normal oil field operations. The precipitates can nucleate on down hole pipe walls, causing the buildup of hard scales in some tubular in a pipe string, while leaving others virtually untouched. Once the scale buildup is sufficient to restrict flow in the string significantly, the tubular are removed from service. Once removed, tubular are transported to storage yards for storage, subsequent inspection, and possible recycling. Many of the tubular are never returned to service, either because the threads were too damaged, pipe walls too thin, or the scale buildup too thick. Historically, the tubular refurbishment industry used primarily one of two processes, either a high-pressure water lance or a dry, abrasive 'rattling' process to ream pipes free of scale buildup. The dry rattling process was primarily for touching up new pipes that have rusted slightly during storage; however, pipes with varying levels of scale were reamed, leaving only a thin coating of scale on the inner diameter, and then returned to service. Chemically, radium is an analog for barium, and radium is present in parts-per-million quantities in the brines produced from downhole pumping operations. Thus, some of the scales contain radium salts. When the radium-bearing scales are reamed with a dry process there is the possibility of generating radioactive aerosols, as well as bulk waste materials. At Texas A and M University, and under the university's radioactive materials broad scope license, an outdoor laboratory was constructed and operated with dry rattling equipment restored to the 'as was' condition typical of historical pipe cleaning yards. A battery of measurements were obtained to determine the radiological and aerodynamic properties of scale-waste products liberated from the inner surfaces of a variety of tubular

  13. Integrated biodosimetry in large scale radiological events. Opportunities for civil military co-operation

    International Nuclear Information System (INIS)

    Port, M.; Eder, S.F.; Lamkowski, A.; Majewski, M.; Abend, M.

    2016-01-01

    Radiological events like large scale radiological or nuclear accidents, terroristic attacks with radionuclide dispersal devices require rapid and precise medical classification (''triage'') and medical management of a large number of patients. Estimates on the absorbed dose and in particular predictions of the radiation induced health effects are mandatory for optimized allocation of limited medical resources and initiation of patient centred treatment. Among the German Armed Forces Medical Services the Bundeswehr Institute of Radiobiology offers a wide range of tools for the purpose of medical management to cope with different scenarios. The forward deployable mobile Medical Task Force has access to state of the art methodologies summarized into approaches such as physical dosimetry (including mobile gammaspectroscopy), clinical ''dosimetry'' (prodromi, H-Modul) and different means of biological dosimetry (e.g. dicentrics, high throughput gene expression techniques, gamma-H2AX). The integration of these different approaches enables trained physicians of the Medical Task Force to assess individual health injuries as well as prognostic evaluation, considering modern treatment options. To enhance the capacity of single institutions, networking has been recognized as an important emergency response strategy. The capabilities of physical, biological and clinical ''dosimetry'' approaches spanning from low up to high radiation exposures will be discussed. Furthermore civil military opportunities for combined efforts will be demonstrated.

  14. Time Scale in Least Square Method

    Directory of Open Access Journals (Sweden)

    Özgür Yeniay

    2014-01-01

    Full Text Available Study of dynamic equations in time scale is a new area in mathematics. Time scale tries to build a bridge between real numbers and integers. Two derivatives in time scale have been introduced and called as delta and nabla derivative. Delta derivative concept is defined as forward direction, and nabla derivative concept is defined as backward direction. Within the scope of this study, we consider the method of obtaining parameters of regression equation of integer values through time scale. Therefore, we implemented least squares method according to derivative definition of time scale and obtained coefficients related to the model. Here, there exist two coefficients originating from forward and backward jump operators relevant to the same model, which are different from each other. Occurrence of such a situation is equal to total number of values of vertical deviation between regression equations and observation values of forward and backward jump operators divided by two. We also estimated coefficients for the model using ordinary least squares method. As a result, we made an introduction to least squares method on time scale. We think that time scale theory would be a new vision in least square especially when assumptions of linear regression are violated.

  15. Event classification related to overflow of solvent containing uranium according to the INES scale (International Nuclear and Radiological Event Scale)

    International Nuclear Information System (INIS)

    Dourado, Eneida R.G.; Assis, Juliana T. de; Lage, Ricardo F.; Lopes, Karina B.

    2013-01-01

    This paper aims to frame the event overflow organic solvent rich in uranium, from a decanter of ore beneficiation plant, caused by the fall in the supply of electricity, according to the criteria established by the International Nuclear Event Scale and radiological (INES), facilitating the understanding of the occurrence and communication with the public regarding the radiation safety aspects involved. With the fall of electricity, routine procedures in situations of installation stop were performed, however, due to operational failure, the valve on the transfer line liquor was not closed. Thus, the mixer continued being fed with liquor, that led the consequent leakage of solvent loaded with uranium. It reached the drainage system, and the box of rainwater harvesting of the plant. However, immediately after the detection of the event, corrective actions were initiated and the overflow was contained. Regulatory agencies followed the removal of the solvent and on the results of the analysis of environmental monitoring, found that the event did not provide exposure to workers or any other impact. Therefore, comparing the characteristics of the event and the guidelines proposed by the INES scale, it is concluded that the classification of the event is below scale/level 0, confirming the absence of risk to the local population, workers and the environment

  16. Steffensen's Integral Inequality on Time Scales

    Directory of Open Access Journals (Sweden)

    Ozkan Umut Mutlu

    2007-01-01

    Full Text Available We establish generalizations of Steffensen's integral inequality on time scales via the diamond- dynamic integral, which is defined as a linear combination of the delta and nabla integrals.

  17. Hardy type inequalities on time scales

    CERN Document Server

    Agarwal, Ravi P; Saker, Samir H

    2016-01-01

    The book is devoted to dynamic inequalities of Hardy type and extensions and generalizations via convexity on a time scale T. In particular, the book contains the time scale versions of classical Hardy type inequalities, Hardy and Littlewood type inequalities, Hardy-Knopp type inequalities via convexity, Copson type inequalities, Copson-Beesack type inequalities, Liendeler type inequalities, Levinson type inequalities and Pachpatte type inequalities, Bennett type inequalities, Chan type inequalities, and Hardy type inequalities with two different weight functions. These dynamic inequalities contain the classical continuous and discrete inequalities as special cases when T = R and T = N and can be extended to different types of inequalities on different time scales such as T = hN, h > 0, T = qN for q > 1, etc.In this book the authors followed the history and development of these inequalities. Each section in self-contained and one can see the relationship between the time scale versions of the inequalities and...

  18. JY1 time scale: a new Kalman-filter time scale designed at NIST

    International Nuclear Information System (INIS)

    Yao, Jian; Parker, Thomas E; Levine, Judah

    2017-01-01

    We report on a new Kalman-filter hydrogen-maser time scale (i.e. JY1 time scale) designed at the National Institute of Standards and Technology (NIST). The JY1 time scale is composed of a few hydrogen masers and a commercial Cs clock. The Cs clock is used as a reference clock to ease operations with existing data. Unlike other time scales, the JY1 time scale uses three basic time-scale equations, instead of only one equation. Also, this time scale can detect a clock error (i.e. time error, frequency error, or frequency drift error) automatically. These features make the JY1 time scale stiff and less likely to be affected by an abnormal clock. Tests show that the JY1 time scale deviates from the UTC by less than  ±5 ns for ∼100 d, when the time scale is initially aligned to the UTC and then is completely free running. Once the time scale is steered to a Cs fountain, it can maintain the time with little error even if the Cs fountain stops working for tens of days. This can be helpful when we do not have a continuously operated fountain or when the continuously operated fountain accidentally stops, or when optical clocks run occasionally. (paper)

  19. Some nonlinear dynamic inequalities on time scales

    Indian Academy of Sciences (India)

    unify and extend some inequalities by Pachpatte in [13]. This paper is organized as follows: In §2 we give some preliminary results with respect to the calculus on time scales, which can also be found in [4, 5]. In §3 we deal with our nonlinear dynamic inequalities on time scales. In §4 we give an example to illustrate our main ...

  20. Prepopulated radiology report templates: a prospective analysis of error rate and turnaround time.

    Science.gov (United States)

    Hawkins, C M; Hall, S; Hardin, J; Salisbury, S; Towbin, A J

    2012-08-01

    Current speech recognition software allows exam-specific standard reports to be prepopulated into the dictation field based on the radiology information system procedure code. While it is thought that prepopulating reports can decrease the time required to dictate a study and the overall number of errors in the final report, this hypothesis has not been studied in a clinical setting. A prospective study was performed. During the first week, radiologists dictated all studies using prepopulated standard reports. During the second week, all studies were dictated after prepopulated reports had been disabled. Final radiology reports were evaluated for 11 different types of errors. Each error within a report was classified individually. The median time required to dictate an exam was compared between the 2 weeks. There were 12,387 reports dictated during the study, of which, 1,173 randomly distributed reports were analyzed for errors. There was no difference in the number of errors per report between the 2 weeks; however, radiologists overwhelmingly preferred using a standard report both weeks. Grammatical errors were by far the most common error type, followed by missense errors and errors of omission. There was no significant difference in the median dictation time when comparing studies performed each week. The use of prepopulated reports does not alone affect the error rate or dictation time of radiology reports. While it is a useful feature for radiologists, it must be coupled with other strategies in order to decrease errors.

  1. Long term stability of atomic time scales

    Science.gov (United States)

    Petit, Gérard; Arias, Elisa Felicitas

    2012-08-01

    International Atomic Time TAI gets its stability from some 400 atomic clocks worldwide that generate the free atomic scale EA L and its accuracy from a small number of primary frequency standards (PFS) which frequency measurements are used to steer the EAL frequency. Because TAI is computed in "real - time" (every month) and has operational constraints, it is not optimal and the BIPM computes in deferred time another time scale TT(BIPM), which is based on a weighted average of the evaluations of TAI frequency by the PFS. We show that a point has been reached where the stability of atomic time scales, the accuracy of primary frequency standards, and the capabilities of frequency transfer are approximately at a similar level, in the low 10 - 16 in relative frequency. The goal is now to reach and surpass 1x10 - 16 and the three fields are in various stages of advancement towards this aim. We review the stability and accuracy recently achieved by frequency standards, focusing on primary frequency standards on one hand, and on new secondary realizations e.g. based on optical transitions on the other hand. We study how these performances can translate to the performance of atomic time scales, and the possible implications of the availability of new high - accuracy frequency standards operating on a regular basis. Finally we show how time transfer is trying to keep up with the progresses of frequency standards. Time transfer is presently the limiting factor at short averaging time (e.g. 1 - 2 weeks) but it should not be limiting the long term stability of atomic time scales, which is the main need of many applications in astronomy.

  2. Changes in the American Interventional Radiology Literature: Comparison over a 10-Year Time Period

    International Nuclear Information System (INIS)

    Ray, Charles E.; Gupta, Rajan; Blackwell, John

    2006-01-01

    Purpose. To determine the changes that occurred regarding interventional radiologic research in the major American radiology journals between 1992-1993 and 2002-2003. Methods. Articles published in three major American radiology journals (Journal of Vascular and Interventional Radiology, American Journal of Roentgenology, and Radiology) during two distinct 24-month time periods (1992-1993 and 2002-2003) were evaluated. All articles judged to be pertinent to the interventional radiologic community were included. Investigations included in journal subheadings other than 'interventional' or 'vascular radiology' were included if the emphasis of the article was on a vascular imaging modality or peripheral intervention. Exclusions included: case reports, technical reports, letters to the editor, breast interventions, and primary neurointerventions. Data were collected regarding the affiliations of the primary author (nationality, hospital type, department); primary category of interest of the investigation; funding information; and study design variables. Two-by-two chi-squared statistical analyses were performed comparing the variables from the early and late data sets. Results. A total of 405 articles met the inclusion criteria for the early data set (1992-1993); 488 articles met the inclusion criteria for the late data set (2002-2003). Variables that demonstrated a statistically significant decrease from the early data set to the late data set included: articles in which the primary author was from a department of radiology (91.1% vs. 86.3%; p < 0.025); articles written by a primary author who was American (69.4% vs. 44.6%; p < 0.001); and articles with a primary category of investigation that had a nonvascular intervention focus (22.7% vs. 11.9%; p < 0.001). Variables that demonstrated a statistically significant increase from the early data set to the late data set included primary authors from Western Europe (18.0% vs. 30.1%; p < 0.001) and Asia (6.6% vs. 18.4%; p

  3. The German Radiological Society and the Protagonists of Radiology during the Time of National Socialism--State of Research, Explanation Attempts, Desiderata and Research Prospects.

    Science.gov (United States)

    Schmidt, M; Winzen, T; Groß, D

    2015-06-01

    The intention of the authors is the recognition and critical analysis of efforts to study the history of the German Radiological Society during the time of National Socialism from 1933 to 1945 with the goal of determining existing desiderata and identifying the resulting research prospects. There is a need to study concrete individual biographies of radiologists (members of the German Radiological Society, perpetrators, and victims) and their careers before and after 1945 as well as the importance of the interdisciplinarity of the discipline and the lack of institutional involvement during the "Third Reich". Moreover, the comparatively difficult starting situation of the study of the history of the German Radiological Society is discussed. © Georg Thieme Verlag KG Stuttgart · New York.

  4. The German Radiological Society and the protagonists of radiology during the time of National Socialism. State of research, explanation attempts, desiderata and research prospects

    International Nuclear Information System (INIS)

    Schmidt, M.; Winzen, T.; Gross, D.

    2015-01-01

    The intention of the authors is the recognition and critical analysis of efforts to study the history of the German Radiological Society during the time of National Socialism from 1933 to 1945 with the goal of determining existing desiderata and identifying the resulting research prospects. There is a need to study concrete individual biographies of radiologists (members of the German Radiological Society, perpetrators, and victims) and their careers before and after 1945 as well as the importance of the interdisciplinarity of the discipline and the lack of institutional involvement during the ''Third Reich''. Moreover, the comparatively difficult starting situation of the study of the history of the German Radiological Society is discussed.

  5. Nanoscopic designs of radiological protection in environmental scale for the Fukushima nuclear accident: Strategy by dispersion, dissolution, and filtration

    International Nuclear Information System (INIS)

    Woo, Tae Ho

    2016-01-01

    Highlights: • New kind of radiological protection concept is introduced. • The shielding concept is accompanied with the water spray system. • The solubility of radioactive material could be used for protection. • Practical method is suggested. • The system is variable by the random number quantities. - Abstract: The environmental defense system in the nuclear power plants (NPPs) is investigated in the aspect of the environmental scale incorporated with atmospheric and marine sectors. The object is to find the radiological protection protocol in the environmental scale which is different from the conventional three kinds of radiological protection principles. Conventional laboratory based principles are not applicable in the mass failure accident such as the case of Fukushima disaster. This newly introduced protocol has many useful applications for the nature treatment oriented methods where the atmospheric protection of dispersion and dissolution is performed first and the filtration of seawater would follow. The maximum and minimum values in fan velocity are about 7.5 m/s and 5.3 m/s respectively. For the spray system, the mole fractions by the water spray are shown where maximum and minimum values are 6.57 × 10 −17 and 8.84 × 10 −19 moles respectively. The maximum and minimum values of discharged values in filtration are 99.4 and 1.3 square velocity (m/s), respectively. The total and general radiological protection concept is suggested in the nanoscopic molecular scale performance.

  6. Conformable fractional Dirac system on time scales

    Directory of Open Access Journals (Sweden)

    Tuba Gulsen

    2017-07-01

    Full Text Available Abstract We study the conformable fractional (CF Dirac system with separated boundary conditions on an arbitrary time scale T $\\mathbb{T}$ . Then we extend some basic spectral properties of the classical Dirac system to the CF case. Eventually, some asymptotic estimates for the eigenfunction of the CF Dirac eigenvalue problem are obtained on  T $\\mathbb{T} $ . So, we provide a constructive procedure for the solution of this problem. These results are important steps to consolidate the link between fractional calculus and time scale calculus in spectral theory.

  7. Multivariable dynamic calculus on time scales

    CERN Document Server

    Bohner, Martin

    2016-01-01

    This book offers the reader an overview of recent developments of multivariable dynamic calculus on time scales, taking readers beyond the traditional calculus texts. Covering topics from parameter-dependent integrals to partial differentiation on time scales, the book’s nine pedagogically oriented chapters provide a pathway to this active area of research that will appeal to students and researchers in mathematics and the physical sciences. The authors present a clear and well-organized treatment of the concept behind the mathematics and solution techniques, including many practical examples and exercises.

  8. The radiological impact of radionuclides dispersed on a regional and global scale: Methods for assessment and their application

    International Nuclear Information System (INIS)

    1985-01-01

    The basic features of models, developed to assess the radiological impact of radionuclides that become dispersed on a regional or global scale, have been reviewed. Particular attention has been given to identifying the important processes that need to be modelled in order to make a reliable estimate of the radiological impact, rather than attempting to judge which models are the most appropriate. Judgements on the latter will be sensitive to the particular application; in some cases a very simple approach may be sufficient, whereas in others a more rigorous analysis may be necessary. Two aspects are important in assessing the radiological impact: these are the exposure of critical groups, and the collective dose in the exposed population

  9. Assessment of self-help methods to reduce potential exposure to radiological contamination after a large-scale radiological release.

    Science.gov (United States)

    Snyder, Emily; Drake, John; Cardarelli, John; Hall, Kathy; Szabo, Jeff; Demmer, Rick; Lindberg, Michael; Riggs, Karen; James, Ryan

    2014-09-01

    After the release of radioactive materials from a large radiological dispersal device (e.g., dirty bomb), improvised nuclear detonation, or nuclear power plant accident, up to hundreds of square miles may be contaminated. A portion of this area will be evacuated; however, people living in the portion that is not evacuated yet is still contaminated with low-levels of radioactive contamination will be asking for ways they can reduce their exposure. Whether cleaning activities can significantly reduce exposure is not fully understood. In this effort, the ability of cleaning activities to remove cesium (137Cs) was studied. The removal efficacy of cleaning with a commercial product, Simple Green®, was compared to cleaning with water for hard surfaces typically seen in residences. The removal efficacy of laundering fabric material surfaces was also determined for a range of conditions (e.g., fabric material type, wash temperature). During these studies, assessments of the implications of these activities (e.g., cross-contamination, resulting waste streams) were also completed. Simple Green and water were effective for removing 137Cs from plastic laminate and vinyl flooring (93.4-96.8%) but were not effective for removing 137Cs from painted wallboard and wood (7.3-68.1%). It was also determined that there was no significant difference between the two cleaners on all of the surfaces, except plastic laminate, for which Simple Green was slightly more effective. Laundering was effective for removing 137Cs contamination from polyester and cotton swatches and cotton comforters (up to 96.8% in the single swatch testing).

  10. Time scales in tidal disruption events

    Directory of Open Access Journals (Sweden)

    Krolik J.

    2012-12-01

    Full Text Available We explore the temporal structure of tidal disruption events pointing out the corresponding transitions in the lightcurves of the thermal accretion disk and of the jet emerging from such events. The hydrodynamic time scale of the disrupted star is the minimal time scale of building up the accretion disk and the jet and it sets a limit on the rise time. This suggest that Swift J1644+57, that shows several flares with a rise time as short as a few hundred seconds could not have arisen from a tidal disruption of a main sequence star whose hydrodynamic time is a few hours. The disrupted object must have been a white dwarf. A second important time scale is the Eddington time in which the accretion rate changes form super to sub Eddington. It is possible that such a transition was observed in the light curve of Swift J2058+05. If correct this provides interesting constraints on the parameters of the system.

  11. INES: The International Nuclear and Radiological Event Scale User's Manual. 2008 Edition

    International Nuclear Information System (INIS)

    2009-05-01

    The International Nuclear and Radiological Event Scale is used for promptly and consistently communicating to the public the safety significance of events associated with sources of radiation. It covers a wide spectrum of practices, including industrial use such as radiography, use of radiation sources in hospitals, activities at nuclear facilities, and the transport of radioactive material. By putting events from all these practices into a proper perspective, use of INES can facilitate a common understanding between the technical community, the media and the public. The scale was developed in 1990 by international experts convened by the IAEA and the OECD Nuclear Energy Agency (OECD/NEA). It originally reflected the experience gained from the use of similar scales in France and Japan as well as consideration of possible scales in several countries. Since then, the IAEA has managed its development in cooperation with the OECD/NEA and with the support of more than 60 designated National Officers who officially represent the INES member States in the biennial technical meeting of INES. Initially the scale was applied to classify events at nuclear power plants, and then was extended and adapted to enable it to be applied to all installations associated with the civil nuclear industry. More recently, it has been extended and adapted further to meet the growing need for communication of the significance of all events associated with the transport, storage and use of radioactive material and radiation sources. This revised manual brings together the guidance for all uses into a single document. Events are classified on the scale at seven levels: Levels 4-7 are termed 'accidents' and Levels 1-3 'incidents'. Events without safety significance are classified as 'Below Scale/Level 0'. Events that have no safety relevance with respect to radiation or nuclear safety are not classified on the scale. For communication of events to the public, a distinct phrase has been

  12. Some Nonlinear Dynamic Inequalities on Time Scales

    Indian Academy of Sciences (India)

    The aim of this paper is to investigate some nonlinear dynamic inequalities on time scales, which provide explicit bounds on unknown functions. The inequalities given here unify and extend some inequalities in (B G Pachpatte, On some new inequalities related to a certain inequality arising in the theory of differential ...

  13. Some Nonlinear Integral Inequalities on Time Scales

    Directory of Open Access Journals (Sweden)

    Li Wei Nian

    2007-01-01

    Full Text Available The purpose of this paper is to investigate some nonlinear integral inequalities on time scales. Our results unify and extend some continuous inequalities and their corresponding discrete analogues. The theoretical results are illustrated by a simple example at the end of this paper.

  14. The Second Noether Theorem on Time Scales

    Directory of Open Access Journals (Sweden)

    Agnieszka B. Malinowska

    2013-01-01

    Full Text Available We extend the second Noether theorem to variational problems on time scales. As corollaries we obtain the classical second Noether theorem, the second Noether theorem for the h-calculus and the second Noether theorem for the q-calculus.

  15. Implications of short time scale dynamics on long time processes

    Directory of Open Access Journals (Sweden)

    Krystel El Hage

    2017-11-01

    Full Text Available This review provides a comprehensive overview of the structural dynamics in topical gas- and condensed-phase systems on multiple length and time scales. Starting from vibrationally induced dissociation of small molecules in the gas phase, the question of vibrational and internal energy redistribution through conformational dynamics is further developed by considering coupled electron/proton transfer in a model peptide over many orders of magnitude. The influence of the surrounding solvent is probed for electron transfer to the solvent in hydrated I−. Next, the dynamics of a modified PDZ domain over many time scales is analyzed following activation of a photoswitch. The hydration dynamics around halogenated amino acid side chains and their structural dynamics in proteins are relevant for iodinated TyrB26 insulin. Binding of nitric oxide to myoglobin is a process for which experimental and computational analyses have converged to a common view which connects rebinding time scales and the underlying dynamics. Finally, rhodopsin is a paradigmatic system for multiple length- and time-scale processes for which experimental and computational methods provide valuable insights into the functional dynamics. The systems discussed here highlight that for a comprehensive understanding of how structure, flexibility, energetics, and dynamics contribute to functional dynamics, experimental studies in multiple wavelength regions and computational studies including quantum, classical, and more coarse grained levels are required.

  16. Augmenting the impact of technology adoption with financial incentive to improve radiology report signature times.

    Science.gov (United States)

    Andriole, Katherine P; Prevedello, Luciano M; Dufault, Allen; Pezeshk, Parham; Bransfield, Robert; Hanson, Richard; Doubilet, Peter M; Seltzer, Steven E; Khorasani, Ramin

    2010-03-01

    Radiology report signature time (ST) can be a substantial component of total report turnaround time. Poor turnaround time resulting from lengthy ST can adversely affect patient care. The combination of technology adoption with financial incentive was evaluated to determine if ST improvement can be augmented and sustained. This prospective study was performed at a 751-bed, urban, tertiary care adult teaching hospital. Test-site imaging volume approximated 48,000 examinations per month. The radiology department has 100 trainees and 124 attending radiologists serving multiple institutions. Over a study period of 4 years and 4 months, three interventions focused on radiologist signature performance were implemented: 1) a notification paging application that alerted radiologists when reports were ready for signature, 2) a picture archiving and communications systems (PACS)-integrated speech recognition report generation system, and 3) a departmental financial incentive to reward radiologists semiannually for ST performance. Signature time was compared before and after the interventions. Wilcoxon and linear regression statistical analyses were used to assess the significance of trends. Technology adoption (paging plus speech recognition) reduced median ST from >5 to 24 to 15 to 18 hours (P financial incentive further improved 80th-percentile ST to 4 to 8 hours (P Technology interventions coupled with financial incentive can result in synergistic and sustainable improvement in radiologist report-signing behavior. The addition of a financial incentive leads to better performance than that achievable through technology alone.

  17. Event classification related to overflow of solvent containing uranium according to the INES scale (International Nuclear and Radiological Event Scale); Classificacao do evento de transbordamento de solvente contendo uranio segundo a escala INES (International Nuclear and Radiological Event Scale)

    Energy Technology Data Exchange (ETDEWEB)

    Dourado, Eneida R.G.; Assis, Juliana T. de; Lage, Ricardo F., E-mail: cneida@inb.gov.br, E-mail: julianateixeira@inb.gov.br, E-mail: rlage@inb.gov.br [lndustrias Nucleares do Brasil S/A (CLISE.P/INB), Rio de Janeiro, RJ (Brazil). Coordenacao de Licenciamento Nuclear e Ambiental, Saude e Seguranca; Lopes, Karina B., E-mail: karina@inb.gov.br [lndustrias Nucleares do Brasil S/A (CPRAD/INB), Rio de Janeiro, RJ (Brazil). Coordenacao de Protecao Radiologica

    2013-11-01

    This paper aims to frame the event overflow organic solvent rich in uranium, from a decanter of ore beneficiation plant, caused by the fall in the supply of electricity, according to the criteria established by the International Nuclear Event Scale and radiological (INES), facilitating the understanding of the occurrence and communication with the public regarding the radiation safety aspects involved. With the fall of electricity, routine procedures in situations of installation stop were performed, however, due to operational failure, the valve on the transfer line liquor was not closed. Thus, the mixer continued being fed with liquor, that led the consequent leakage of solvent loaded with uranium. It reached the drainage system, and the box of rainwater harvesting of the plant. However, immediately after the detection of the event, corrective actions were initiated and the overflow was contained. Regulatory agencies followed the removal of the solvent and on the results of the analysis of environmental monitoring, found that the event did not provide exposure to workers or any other impact. Therefore, comparing the characteristics of the event and the guidelines proposed by the INES scale, it is concluded that the classification of the event is below scale/level 0, confirming the absence of risk to the local population, workers and the environment.

  18. Named entity recognition of follow-up and time information in 20 000 radiology reports

    Science.gov (United States)

    Xu, Yan; Tsujii, Junichi

    2012-01-01

    Objective To develop a system to extract follow-up information from radiology reports. The method may be used as a component in a system which automatically generates follow-up information in a timely fashion. Methods A novel method of combining an LSP (labeled sequential pattern) classifier with a CRF (conditional random field) recognizer was devised. The LSP classifier filters out irrelevant sentences, while the CRF recognizer extracts follow-up and time phrases from candidate sentences presented by the LSP classifier. Measurements The standard performance metrics of precision (P), recall (R), and F measure (F) in the exact and inexact matching settings were used for evaluation. Results Four experiments conducted using 20 000 radiology reports showed that the CRF recognizer achieved high performance without time-consuming feature engineering and that the LSP classifier further improved the performance of the CRF recognizer. The performance of the current system is P=0.90, R=0.86, F=0.88 in the exact matching setting and P=0.98, R=0.93, F=0.95 in the inexact matching setting. Conclusion The experiments demonstrate that the system performs far better than a baseline rule-based system and is worth considering for deployment trials in an alert generation system. The LSP classifier successfully compensated for the inherent weakness of CRF, that is, its inability to use global information. PMID:22771530

  19. Delay times between harvesting or collection of food products and consumption for use in radiological assessments

    International Nuclear Information System (INIS)

    Jones, A L; Sherwood, J C

    2009-01-01

    From a radiological protection point of view, the inclusion of delay times when carrying out assessments of dose from consumption of foods should be considered. A review of delay times has been carried out to update a report published in 1983, to take account of changes and modernisations in industrial food processes, together with changes in diet and popularity of different foods in the United Kingdom. The new review considered more foods and data for existing foods have been reconsidered to check whether manufacturing processes or procedures have changed the shelf-life of any products. For some foods there have been changes made to the recommended delay times because of changes in manufacture or handling of the fresh foodstuff. A discussion is also included on the appropriate use of delay times in dose assessments.

  20. The deployment of an innovative real-time radiological soil characterization system

    International Nuclear Information System (INIS)

    Allen, David; Danahy, Raymond; Laird, Gregory; Seiller, Dale; White, Joan; Janke, Robert

    2000-01-01

    Fluor Fernald Inc., in conjunction with partners from Argonne National Laboratory, the Department of Energy's Environmental Measurements Laboratory, and Idaho National Engineering and Environmental Laboratory, has developed a program for characterizing radiological contaminants in soil in real time. The soil characterization system in use at the Fernald Environmental Management Project (FEMP) for over three years combines gamma ray spectrometry equipment with other technologies to produce a system that can scan large areas of ground and produce color coded maps which display quantitative information regarding isotopic contamination patterns. Software running on a battery powered lap-top computer, is used to control acquisition of gamma spectral data to link the spectral Information with precise detector position measurements from Global Positioning System (GPS) satellites, and to control transmission of data to a central station or van via a wireless Ethernet link where Surfer6 mapping software is used to produce maps showing the position and amount of each target analyte. Either sodium iodide (NaI) gamma ray detectors mounted on three different vehicles for mobile measurements or stationary tripod-mounted hyper-pure germanium (HPGe) detectors can be used in this system to radiologically characterize soil. The operational and performance characteristics, as well as the strengths and limitations of each of these units, will be described. The isotopic information generated by this system can be made available to remediation project mangers within an hour after the completion of a scan to aid in determination of excavation footprints, segregation of contaminated soil and verification of contamination removal. The immediate availability of radiological characterization data made possible by this real-time scanning system has allowed Fluor Fernald to accelerate remediation schedules and reduce costs by avoiding excavation delays and expensive and time consuming

  1. Early Warning Systems at Different Time Scales

    Science.gov (United States)

    Bain, C.

    2014-12-01

    Early Warning Systems (EWS) reduce the negative aspects of natural hazard impacts on vulnerable communities. Despite its frequent use as a term there is no real 'one size fits all' approach to EWS and the system may comprise of different elements depending on the time scale of the hazard, the quality of the information available to make decisions, as well as the population needs and habits. In most developing countries, the primary hydro-meteorological hazards are droughts and floods. These two hazards demand very different approaches: droughts occur over long time scales and are generally a consequence of a gradual process of reduced rainfall across a rainy season; Floods may be caused on seasonal timescales as well due to an overactive rainy season, but the most extreme consequences and loss of life are often suffered at short timescales and relate to flash flooding caused by severe thunderstorms, monsoon extremes and tropical cyclones. This presentation will address the issues around implementing successful EWS and how these can be targeted to different time scales of hazards. Case studies illustrating the benefits of early information use and action will be shown along with open questions for debate on how the science community might better engage and help develop solutions to hazard warning.

  2. Improving Emergency Department radiology transportation time: a successful implementation of lean methodology.

    Science.gov (United States)

    Hitti, Eveline A; El-Eid, Ghada R; Tamim, Hani; Saleh, Rana; Saliba, Miriam; Naffaa, Lena

    2017-09-05

    Emergency Department overcrowding has become a global problem and a growing safety and quality concern. Radiology and laboratory turnaround time, ED boarding and increased ED visits are some of the factors that contribute to ED overcrowding. Lean methods have been used in the ED to address multiple flow challenges from improving door-to-doctor time to reducing length of stay. The objective of this study is to determine the effectiveness of using Lean management methods on improving Emergency Department transportation times for plain radiography. We performed a before and after study at an academic urban Emergency Department with 49,000 annual visits after implementing a Lean driven intervention. The primary outcome was mean radiology transportation turnaround time (TAT). Secondary outcomes included overall study turnaround time from order processing to preliminary report time as well as ED length of stay. All ED patients undergoing plain radiography 6 months pre-intervention were compared to all ED patients undergoing plain radiography 6 months post-intervention after a 1 month washout period. Post intervention there was a statistically significant decrease in the mean transportation TAT (mean ± SD: 9.87 min ± 15.05 versus 22.89 min ± 22.05, respectively, p-value transportation TAT ≤ 10 min, as compared to 32.3% in the pre-intervention period, p-value transportation time to plain radiography in the Emergency Department as well as improving process reliability.

  3. Measuring and managing radiologist workload: measuring radiologist reporting times using data from a Radiology Information System

    International Nuclear Information System (INIS)

    Cowan, Ian A.; MacDonald, Sharon L.S.; Floyd, Richard A.

    2013-01-01

    Historically, there has been no objective method of measuring the time required for radiologists to produce reports during normal work. We have created a technique for semi-automated measurement of radiologist reporting time, and through it produced a robust set of absolute time requirements and relative value units for consultant reporting of diagnostic examinations in our hospital. A large sample of reporting times, recorded automatically by the Radiology Information System (COMRAD, Software Innovations, Christchurch, New Zealand) along with the description of each examination being reported, was placed in a database. Analysis was confined to diagnostic reporting by consultant radiologists. A spreadsheet was produced, listing the total number and the frequency of reporting times of each distinct examination. Outliers with exceptionally long report times (more than 10min for plain radiography, 30min for ultrasound, or 60min for CT or MRI with some exceptions) were culled; this removed 9.5% of the total. Complex CTs requiring separate workstation time were assigned times by consensus. The median time for the remainder of each sample was the assigned absolute reporting time in minutes and seconds. Relative value units were calculated using the reporting time for a single view department chest X-ray of 1min 38s including verifying a report made using speech recognition software. A schedule of absolute and relative values, based on over 179,000 reports, forms Table 2 of this paper. The technique provides a schedule of reporting times with reduced subjective input, which is more robust than existing systems for measuring reporting time.

  4. EDITORIAL: Special issue on time scale algorithms

    Science.gov (United States)

    Matsakis, Demetrios; Tavella, Patrizia

    2008-12-01

    This special issue of Metrologia presents selected papers from the Fifth International Time Scale Algorithm Symposium (VITSAS), including some of the tutorials presented on the first day. The symposium was attended by 76 persons, from every continent except Antarctica, by students as well as senior scientists, and hosted by the Real Instituto y Observatorio de la Armada (ROA) in San Fernando, Spain, whose staff further enhanced their nation's high reputation for hospitality. Although a timescale can be simply defined as a weighted average of clocks, whose purpose is to measure time better than any individual clock, timescale theory has long been and continues to be a vibrant field of research that has both followed and helped to create advances in the art of timekeeping. There is no perfect timescale algorithm, because every one embodies a compromise involving user needs. Some users wish to generate a constant frequency, perhaps not necessarily one that is well-defined with respect to the definition of a second. Other users might want a clock which is as close to UTC or a particular reference clock as possible, or perhaps wish to minimize the maximum variation from that standard. In contrast to the steered timescales that would be required by those users, other users may need free-running timescales, which are independent of external information. While no algorithm can meet all these needs, every algorithm can benefit from some form of tuning. The optimal tuning, and even the optimal algorithm, can depend on the noise characteristics of the frequency standards, or of their comparison systems, the most precise and accurate of which are currently Two Way Satellite Time and Frequency Transfer (TWSTFT) and GPS carrier phase time transfer. The interest in time scale algorithms and its associated statistical methodology began around 40 years ago when the Allan variance appeared and when the metrological institutions started realizing ensemble atomic time using more than

  5. Facilitating process changes in meal delivery and radiological testing to improve inpatient insulin timing using six sigma method.

    Science.gov (United States)

    Yamamoto, J Jay; Malatestinic, Bill; Lehman, Angela; Juneja, Rattan

    2010-01-01

    The objective of this project was to improve the timing of inpatient insulin administration related to meal delivery and the scheduling of radiology tests by Lean Six Sigma method. A multidisciplinary hospital team and a Six Sigma team from a pharmaceutical manufacturer collaborated to evaluate food delivery and radiology scheduling processes related to the timing of insulin administration. Key factors leading to problems within each system were addressed to improve the efficiency of each process while improving the timeliness of glucose testing and insulin administration. Standardizing the food delivery schedule and utilizing scorecards to track on-time meal deliveries to the floor enabled nursing to more accurately administer insulin in coordination with the delivery of meals. Increasing communication and restricting the scheduling of inpatient procedures during mealtimes reduced disruptions to insulin administration. Data at 6 months postimplementation demonstrated that the institution met goals for most primary outcome metrics including increasing on-time meal delivery and the proportion of patients taking insulin scheduled for radiology tests during appropriate times. By implementing the recommendations identified via Lean Six Sigma, this collaborative effort improved the timing of inpatient insulin administration related to meal delivery and radiology testing.

  6. Development of a real-time extremity dose monitor for personnel in interventional radiology

    International Nuclear Information System (INIS)

    Ban, Nobuhiko; Kusama, Tomoko; Adachi, Akiko

    2000-01-01

    Protection of personnel in interventional radiology is one of the most important issues of radiological protection in medicine. Fluoroscopically guided interventional procedures require the operation near X-ray beam, which brings a considerable hand exposure to the operators. For the purpose of effectual control of their extremity doses, we have developed a real-time extremity dose monitor which is worn on a strap around the wrist. The monitor consists of a silicon semiconductor detector, thin lithium battery and a waterproof frame with a four-digit LED display. Experiment was carried out to examine a response of the monitor to diagnostic X-rays. A practical test was also performed to evaluate usability in the actual interventional procedures. In the experiment, the extremity dose monitor was placed on an arm phantom and exposed to diagnostic X-rays. Readings of the monitor were compared to those of Capintec PS-033 shallow chamber. The monitor was highly sensitive to diagnostic X-rays. It showed a linear response down to doses of a few tens of microsieverts. For high dose-rate exposure, however, a slight decrease in the response was observed, about 10% of counting loss for 80 kV, 40 mA X-ray at one meter from the focus. With regard to energy dependence, variation was within 20% for 60 to 100 kV X-rays. The monitor showed a good angular response in general, except lateral geometry facing the far side from a detector center. In the practical test, hand exposures of medical staff were measured with the extremity dose monitor. They were also asked to fill in a questionnaire regarding size and weight of the monitor, clarity of the display and usefulness. The subjects consisted of physicians, technicians and nurses who engaged in angiography, PTCD, CT-biopsy, barium enema and so on. The readings of the monitor were less than 1 mSv in most cases while 93 mSv was recorded in an extreme case due to direct-beam exposure. In some cases, TLD rings were used together with the

  7. Radiological anatomy - evaluation of integrative education in radiology.

    Science.gov (United States)

    Dettmer, S; Schmiedl, A; Meyer, S; Giesemann, A; Pabst, R; Weidemann, J; Wacker, F K; Kirchhoff, T

    2013-09-01

    Evaluation and analysis of the integrative course "Radiological Anatomy" established since 2007 at the Medical School Hannover (MHH) in comparison with conventional education. Anatomy and radiology are usually taught separately with a considerable time lag. Interdisciplinary teaching of these associated subjects seems logical for several reasons. Therefore, the integrative course "Radiological Anatomy" was established in the second year of medical education, combining these two closely related subjects. This interdisciplinary course was retrospectively evaluated by consideration of a student questionnaire and staff observations. The advantages and disadvantages of integrative teaching in medical education are discussed. The course ratings were excellent (median 1; mean 1.3 on a scale of 1 to 6). This is significantly (p radiology increased during the course (88 %). According to the students' suggestions the course was enhanced by a visitation in the Department of Radiology and the additional topic central nervous system. Integrative teaching of anatomy and radiology was well received by the students. Both, anatomical and radiological comprehension and the motivation to learn were improved. However, it should be considered, that the amount of work and time required by the teaching staff is considerably increased compared to traditional teaching. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Radiological optimization

    International Nuclear Information System (INIS)

    Zeevaert, T.

    1998-01-01

    Radiological optimization is one of the basic principles in each radiation-protection system and it is a basic requirement in the safety standards for radiation protection in the European Communities. The objectives of the research, performed in this field at the Belgian Nuclear Research Centre SCK-CEN, are: (1) to implement the ALARA principles in activities with radiological consequences; (2) to develop methodologies for optimization techniques in decision-aiding; (3) to optimize radiological assessment models by validation and intercomparison; (4) to improve methods to assess in real time the radiological hazards in the environment in case of an accident; (5) to develop methods and programmes to assist decision-makers during a nuclear emergency; (6) to support the policy of radioactive waste management authorities in the field of radiation protection; (7) to investigate existing software programmes in the domain of multi criteria analysis. The main achievements for 1997 are given

  9. Development of real-time radiation exposure dosimetry system using synthetic ruby for interventional radiology

    International Nuclear Information System (INIS)

    Hosokai, Yoshiyuki; Win, Thet Pe; Muroi, Kenzo; Matsumoto, Kenki; Takahashi, Kaito; Usui, Akihito; Saito, Haruo; Kozakai, Masataka

    2017-01-01

    Interventional radiology (IVR) tends to involve long procedures, consequently delivering high radiation doses to the patient. Radiation-induced injuries that occur because of the effect of the high radiation doses are a considerable problem for those performing IVR. For example, skin injuries can include skin erythema if the skin is exposed to radiation doses beyond the threshold level of 2 Gy. One of the reasons for this type of injury is that the local skin dose cannot be monitored in real time. Although there are systems employed to measure the exposure dose, some do not work in real time (such as thermoluminescence dosimeters and fluorescent glass dosimeters), while certain real-time measurement systems that enter the field of view (such as patient skin dosimeters and dosimeters using a nontoxic phosphor) interfere with IVR. However, synthetic ruby has been shown to emit light in response to radiation. The luminous wavelength is 693 nm. It is possible to monitor the radiation dose by detecting the emitted light. However, small synthetic rubies emit a tiny amount of light that is difficult to detect using common systems such as photodiodes. A large enough synthetic ruby to increase the quantity of emitted light would however enter the field of view and interfere with the IVR procedure. Additionally, although a photodiode system could reduce the system size, the data is susceptible to effects from the X-rays and outside temperature. Therefore, use of a sensitive photon counting system as used in nuclear medicine could potentially have a beneficial effect in detecting the weak light signal. A real-time radiation exposure dosimetry system for use in IVR should be sufficiently sensitive, not interfere with the IVR procedure, and ideally have the possibility of development into a system that can provide simultaneous multipoint measurements. This article discusses the development of a realtime radiation exposure dosimetry system for use in IVR that employs a small

  10. Almost Automorphic Functions on the Quantum Time Scale and Applications

    Directory of Open Access Journals (Sweden)

    Yongkun Li

    2017-01-01

    Full Text Available We first propose two types of concepts of almost automorphic functions on the quantum time scale. Secondly, we study some basic properties of almost automorphic functions on the quantum time scale. Then, we introduce a transformation between functions defined on the quantum time scale and functions defined on the set of generalized integer numbers; by using this transformation we give equivalent definitions of almost automorphic functions on the quantum time scale; following the idea of the transformation, we also give a concept of almost automorphic functions on more general time scales that can unify the concepts of almost automorphic functions on almost periodic time scales and on the quantum time scale. Finally, as an application of our results, we establish the existence of almost automorphic solutions of linear and semilinear dynamic equations on the quantum time scale.

  11. Optimization aspects of the ARAC real-time radiological emergency response system

    International Nuclear Information System (INIS)

    Taylor, S.S.; Sullivan, T.J.

    1985-07-01

    The Atmospheric Release Advisory Capability (ARAC) project at the Lawrence Livermore National Laboratory responds to radiological emergencies throughout the Continental United States. Using complex three-dimensional dispersion models to account for the effects of complex meteorology and regional terrain, ARAC simulates the release of radioactive materials and provides dispersion, deposition, and dose calculations that are displayed over local geographic features for use by authorities at the accident/release site. ARAC's response is ensured by a software system that (1) makes optimal use of dispersion models, (2) minimizes the time required to provide projections, and (3) maximizes the fault-tolerance of the system. In this paper we describe ARAC's goals and functionality and the costs associated with its development and use. Specifically, we address optimizations in ARAC notifications, meteorological data collection, the determination of site- and problem-specific parameters, the generation of site-specific topography and geography, the running of models, and the distribution of ARAC products. We also discuss the backup features employed to ensure ARAC's ability to respond

  12. Interplay between multiple length and time scales in complex ...

    Indian Academy of Sciences (India)

    Administrator

    micelles and enzymes, can span several orders of magnitude in length and time scales. The length and time scales of ... length and time scales is required in order to understand and predict structure and dynamics in such com- plex systems. This review .... The late 1980s saw the birth of femtochemistry with Ahmed Zewail ...

  13. Biodosimetry versus physical dosimetry for emergency dose assessment following large-scale radiological exposures

    International Nuclear Information System (INIS)

    McKeever, S.W.S.; Sholom, S.

    2016-01-01

    Existing data on intercomparisons involving biodosimetry or physical dosimetry methods are analyzed and the results interpreted regarding their efficacy in triage in emergency dosimetry following mass casualty radiological events. The biodosimetry technique examined is dicentric chromosome aberrations (DCA). The physical dosimetry techniques include electron paramagnetic resonance (EPR) of biological material (teeth) and physical material (smartphone screen glass), and optically stimulated luminescence (OSL) of electronic components (surface mount resistors) from mobile phones. Issues relating to calibration and interpretation of the data are discussed. An important conclusion of the analysis is that more research is critically needed to interpret the efficacy of the various methods. Included in this needed research are intercomparisons of the various methods in controlled experiments and the need to harmonize protocols. - Highlights: • Utility of bio- and physical dosimetry methods for emergency dosimetry triage. • Analysis of intercomparison data for different bio- and physical dosimetry methods. • The percentage of false positives and false negatives for a simulated IND event. • More research, especially intercomparisons, is required to reduce uncertainties.

  14. Time scales separation for dynamo action

    OpenAIRE

    Dormy, Emmanuel; Gerard-Varet, David

    2008-01-01

    International audience; The study of dynamo action in astrophysical objects classically involves two timescales: the slow diffusive one and the fast advective one. We investigate the possibility of field amplification on an intermediate timescale associated with time dependent modulations of the flow. We consider a simple steady configuration for which dynamo action is not realised. We study the effect of time dependent perturbations of the flow. We show that {some} vanishing {low frequency} ...

  15. Visual Simultaneous Localization And Mapping (VSLAM) methods applied to indoor 3D topographical and radiological mapping in real-time

    Science.gov (United States)

    Hautot, Felix; Dubart, Philippe; Bacri, Charles-Olivier; Chagneau, Benjamin; Abou-Khalil, Roger

    2017-09-01

    New developments in the field of robotics and computer vision enables to merge sensors to allow fast realtime localization of radiological measurements in the space/volume with near-real time radioactive sources identification and characterization. These capabilities lead nuclear investigations to a more efficient way for operators' dosimetry evaluation, intervention scenarii and risks mitigation and simulations, such as accidents in unknown potentially contaminated areas or during dismantling operations

  16. Development of a Real-Time Radiological Area Monitoring Network for Emergency Response at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Bertoldo, N; Hunter, S; Fertig, R; Laguna, G; MacQueen, D

    2004-01-01

    A real-time radiological sensor network for emergency response was developed and deployed at the Lawrence Livermore National Laboratory (LLNL). The Real-Time Radiological Area Monitoring (RTRAM) network is comprised of 16 Geiger-Mueller (GM) sensors positioned on the LLNL Livermore site perimeter to continuously monitor for a radiological condition resulting from a terrorist threat to site security and the health and safety of LLNL personnel. The RTRAM network sensor locations coincide with wind sector directions to provide thorough coverage of the one square mile site. These loW--power sensors are supported by a central command center (CCC) and transmit measurement data back to the CCC computer through the LLNL telecommunications infrastructure. Alarm conditions are identified by comparing current data to predetermined threshold parameters and are validated by comparison with plausible dispersion modeling scenarios and prevailing meteorological conditions. Emergency response personnel are notified of alarm conditions by automatic radio and computer based notifications. A secure intranet provides emergency response personnel with current condition assessment data that enable them to direct field response efforts remotely. The RTRAM network has proven to be a reliable system since initial deployment in August 2001 and maintains stability during inclement weather conditions

  17. Objective quality measurement for audio time-scale modification

    Science.gov (United States)

    Liu, Fang; Lee, Jae-Joon; Kuo, C. C. J.

    2003-11-01

    The recent ITU-T Recommendation P.862, known as the Perceptual Evaluation of Speech Quality (PESQ) is an objective end-to-end speech quality assessment method for telephone networks and speech codecs through the measurement of received audio quality. To ensure that certain network distortions will not affect the estimated subjective measurement determined by PESQ, the algorithm takes into account packet loss, short-term and long-term time warping resulted from delay variation. However, PESQ does not work well for time-scale audio modification or temporal clipping. We investigated the factors that impact the perceived quality when time-scale modification is involved. An objective measurement of time-scale modification is proposed in this research, where the cross-correlation values obtained from time-scale modification synchronization are used to evaluate the quality of a time-scaled audio sequence. This proposed objective measure has been verified by a subjective test.

  18. Exploiting natural scale separation with efficient asynchronous numerical time integration

    Science.gov (United States)

    Rubel, Michael; Leonard, Anthony

    2002-11-01

    The systems of ordinary differential equations that arise in problems of computational fluid mechanics often exhibit time-scale separation in addition to being stiff: each solution variable acts at a small range of time scales relative to the problem as a whole. When only a small fraction of the solution variables act at the fastest scales, conventional timestepping algorithms waste a great deal of effort over-resolving the slow variables. In this talk, I will discuss numerical strategies to take advantage of time-scale separation for more efficient computing. In particular, results from the dead-reckoning algorithm will be presented.

  19. Properties of Some Partial Dynamic Equations on Time Scales

    Directory of Open Access Journals (Sweden)

    Deepak B. Pachpatte

    2013-01-01

    Full Text Available The main objective of the paper is to study the properties of the solution of a certain partial dynamic equation on time scales. The tools employed are based on the application of the Banach fixed-point theorem and a certain integral inequality with explicit estimates on time scales.

  20. Bounds of Certain Dynamic Inequalities on Time Scales

    Directory of Open Access Journals (Sweden)

    Deepak B. Pachpatte

    2014-10-01

    Full Text Available In this paper we study explicit bounds of certain dynamic integral inequalities on time scales. These estimates give the bounds on unknown functions which can be used in studying the qualitative aspects of certain dynamic equations. Using these inequalities we prove the uniqueness of some partial integro-differential equations on time scales.

  1. Temperature dependence of fluctuation time scales in spin glasses

    DEFF Research Database (Denmark)

    Kenning, Gregory G.; Bowen, J.; Sibani, Paolo

    2010-01-01

    Using a series of fast cooling protocols we have probed aging effects in the spin glass state as a function of temperature. Analyzing the logarithmic decay found at very long time scales within a simple phenomenological barrier model, leads to the extraction of the fluctuation time scale of the s...

  2. Time scales of tunneling decay of a localized state

    International Nuclear Information System (INIS)

    Ban, Yue; Muga, J. G.; Sherman, E. Ya.; Buettiker, M.

    2010-01-01

    Motivated by recent time-domain experiments on ultrafast atom ionization, we analyze the transients and time scales that characterize, aside from the relatively long lifetime, the decay of a localized state by tunneling. While the tunneling starts immediately, some time is required for the outgoing flux to develop. This short-term behavior depends strongly on the initial state. For the initial state, tightly localized so that the initial transients are dominated by over-the-barrier motion, the time scale for flux propagation through the barrier is close to the Buettiker-Landauer traversal time. Then a quasistationary, slow-decay process follows, which sets ideal conditions for observing diffraction in time at longer times and distances. To define operationally a tunneling time at the barrier edge, we extrapolate backward the propagation of the wave packet that escaped from the potential. This extrapolated time is considerably longer than the time scale of the flux and density buildup at the barrier edge.

  3. Research on classification of nuclear and radiological accident from IAEA threat category with estimation of INES scale

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Seok Ki [Dept. of Nuclear engineering, Univ of SeJong, Seoul (Korea, Republic of); Kim, Siu [Korea Nuclear International Cooperation Foundation, Daejeon (Korea, Republic of)

    2017-04-15

    As there is increasing use of nuclear energy and radiation while information on nuclear related accidents are accumulated, international interest in nuclear and radiation incidents is increasing rapidly. Because of the specificity of nuclear energy and radiation, the damage caused by such accidents will be spread to the larger area around the accident point due to the radiation and cause biological damage and mental-psychological damage. The purpose of this study is to categorize historical incidents using the Threat Category concept described in the publication of IAEA Safety Guide GS-G-2.1. In addition to categorizing actual events and accidents into Threat Categories, causes of occurrences, the type of radioactive source which leads to the main threats, the type of radiation exposure, and the type of patient are organized in detail. As a result of the analysis of representative historical cases, most accident cases caused by 'Nuclear Energy-Related Business Operator' correspond to 1 (Anomaly) ~ 4 (Accident with Local Consequences) in the INES Scale by IAEA. From the some accident cases, while the radiological damage can be seen to be local, but it can be seen that the possibility of 6 (Serious Accident) can not be absolutely excluded.

  4. Soil moisture memory at sub-monthly time scales

    Science.gov (United States)

    Mccoll, K. A.; Entekhabi, D.

    2017-12-01

    For soil moisture-climate feedbacks to occur, the soil moisture storage must have `memory' of past atmospheric anomalies. Quantifying soil moisture memory is, therefore, essential for mapping and characterizing land-atmosphere interactions globally. Most previous studies estimate soil moisture memory using metrics based on the autocorrelation function of the soil moisture time series (e.g., the e-folding autocorrelation time scale). This approach was first justified by Delworth and Manabe (1988) on the assumption that monthly soil moisture time series can be modelled as red noise. While this is a reasonable model for monthly soil moisture averages, at sub-monthly scales, the model is insufficient due to the highly non-Gaussian behavior of the precipitation forcing. Recent studies have shown that significant soil moisture-climate feedbacks appear to occur at sub-monthly time scales. Therefore, alternative metrics are required for defining and estimating soil moisture memory at these shorter time scales. In this study, we introduce metrics, based on the positive and negative increments of the soil moisture time series, that can be used to estimate soil moisture memory at sub-monthly time scales. The positive increments metric corresponds to a rapid drainage time scale. The negative increments metric represents a slower drying time scale that is most relevant to the study of land-atmosphere interactions. We show that autocorrelation-based metrics mix the two time scales, confounding physical interpretation. The new metrics are used to estimate soil moisture memory at sub-monthly scales from in-situ and satellite observations of soil moisture. Reference: Delworth, Thomas L., and Syukuro Manabe. "The Influence of Potential Evaporation on the Variabilities of Simulated Soil Wetness and Climate." Journal of Climate 1, no. 5 (May 1, 1988): 523-47. doi:10.1175/1520-0442(1988)0012.0.CO;2.

  5. Liquidity spillover in international stock markets through distinct time scales.

    Science.gov (United States)

    Righi, Marcelo Brutti; Vieira, Kelmara Mendes

    2014-01-01

    This paper identifies liquidity spillovers through different time scales based on a wavelet multiscaling method. We decompose daily data from U.S., British, Brazilian and Hong Kong stock markets indices in order to calculate the scale correlation between their illiquidities. The sample is divided in order to consider non-crisis, sub-prime crisis and Eurozone crisis. We find that there are changes in correlations of distinct scales and different periods. Association in finest scales is smaller than in coarse scales. There is a rise on associations in periods of crisis. In frequencies, there is predominance for significant distinctions involving the coarsest scale, while for crises periods there is predominance for distinctions on the finest scale.

  6. AFSC/ABL: Naknek sockeye salmon scale time series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A time series of scale samples (1956 2002) collected from adult sockeye salmon returning to Naknek River were retrieved from the Alaska Department of Fish and Game....

  7. AFSC/ABL: Ugashik sockeye salmon scale time series

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A time series of scale samples (1956 b?? 2002) collected from adult sockeye salmon returning to Ugashik River were retrieved from the Alaska Department of Fish and...

  8. An extended Halanay inequality of integral type on time scales

    Directory of Open Access Journals (Sweden)

    Boqun Ou

    2015-07-01

    Full Text Available In this paper, we obtain a Halanay-type inequality of integral type on time scales which improves and extends some earlier results for both the continuous and discrete cases. Several illustrative examples are also given.

  9. Periodic Solutions for a Delayed Population Model on Time Scales

    OpenAIRE

    Kejun Zhuang; Zhaohui Wen

    2010-01-01

    This paper deals with a delayed single population model on time scales. With the assistance of coincidence degree theory, sufficient conditions for existence of periodic solutions are obtained. Furthermore, the better estimations for bounds of periodic solutions are established.

  10. The effectiveness of service delivery initiatives at improving patients' waiting times in clinical radiology departments: a systematic review.

    Science.gov (United States)

    Olisemeke, B; Chen, Y F; Hemming, K; Girling, A

    2014-12-01

    We reviewed the literature for the impact of service delivery initiatives (SDIs) on patients' waiting times within radiology departments. We searched MEDLINE, EMBASE, CINAHL, INSPEC and The Cochrane Library for relevant articles published between 1995 and February, 2013. The Cochrane EPOC risk of bias tool was used to assess the risk of bias on studies that met specified design criteria. Fifty-seven studies met the inclusion criteria. The types of SDI implemented included extended scope practice (ESP, three studies), quality management (12 studies), productivity-enhancing technologies (PETs, 29 studies), multiple interventions (11 studies), outsourcing and pay-for-performance (one study each). The uncontrolled pre- and post-intervention and the post-intervention designs were used in 54 (95%) of the studies. The reporting quality was poor: many of the studies did not test and/or report the statistical significance of their results. The studies were highly heterogeneous, therefore meta-analysis was inappropriate. The following type of SDIs showed promising results: extended scope practice; quality management methodologies including Six Sigma, Lean methodology, and continuous quality improvement; productivity-enhancing technologies including speech recognition reporting, teleradiology and computerised physician order entry systems. We have suggested improved study design and the mapping of the definitions of patient waiting times in radiology to generic timelines as a starting point for moving towards a situation where it becomes less restrictive to compare and/or pool the results of future studies in a meta-analysis.

  11. Some New Inequalities of Opial's Type on Time Scales

    Directory of Open Access Journals (Sweden)

    Samir H. Saker

    2012-01-01

    Full Text Available We will prove some new dynamic inequalities of Opial's type on time scales. The results not only extend some results in the literature but also improve some of them. Some continuous and discrete inequalities are derived from the main results as special cases. The results can be applied on the study of distribution of generalized zeros of half-linear dynamic equations on time scales.

  12. Proposed classification scale for radiological incidents and accidents; Elaboration d'une echelle de classement des incidents et accidents radiologiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-04-15

    The scale proposed in this report is intended to facilitate communication concerning the severity of incidents and accidents involving the exposure of human beings to ionising radiations. Like the INES, it comprises eight levels of severity and uses the same terms (accident, incident, anomaly, serious and major) for keeping the public and the media informed. In a radiological protection context, the severity of an event is considered as being directly proportional to the risk run by an individual (the probability of developing fatal or non-fatal health effects) following exposure to ionising radiation in an incident or accident situation. However for society, other factors have to be taken into account to determine severity. The severity scale proposed is therefore based on assessment of the individual radiological risk. A severity level corresponding to exposure of a member of the public in an incident or accident situation is determined on the basis of risk assessment concepts and methods derived from international consensus on dose/effect relationships for both stochastic and deterministic effects. The severity of all the possible exposure situations - worker exposure, collective exposure, potential exposure - is determined using a system of weighting in relation to situations involving members of the public. In the case of this scale, to indicate the severity of an event, it is proposed to make use of the most penalizing level of severity, comparing: - the severity associated with the probability of occurrence of deterministic effects and the severity associated with the probability of occurrence of stochastic effects, when the event gives rise to both types of risk; - the severity for members of the public and the severity for exposed workers, when both categories of individuals are involved; - the severity on the proposed radiological protection scale and that obtained using the INES, when radiological protection and nuclear safety aspects are associated with

  13. Characteristic Time Scales of Characteristic Magmatic Processes and Systems

    Science.gov (United States)

    Marsh, B. D.

    2004-05-01

    Every specific magmatic process, regardless of spatial scale, has an associated characteristic time scale. Time scales associated with crystals alone are rates of growth, dissolution, settling, aggregation, annealing, and nucleation, among others. At the other extreme are the time scales associated with the dynamics of the entire magmatic system. These can be separated into two groups: those associated with system genetics (e.g., the production and transport of magma, establishment of the magmatic system) and those due to physical characteristics of the established system (e.g., wall rock failure, solidification front propagation and instability, porous flow). The detailed geometry of a specific magmatic system is particularly important to appreciate; although generic systems are useful, care must be taken to make model systems as absolutely realistic as possible. Fuzzy models produce fuzzy science. Knowledge of specific time scales is not necessarily useful or meaningful unless the hierarchical context of the time scales for a realistic magmatic system is appreciated. The age of a specific phenocryst or ensemble of phenocrysts, as determined from isotopic or CSD studies, is not meaningful unless something can be ascertained of the provenance of the crystals. For example, crystal size multiplied by growth rate gives a meaningful crystal age only if it is from a part of the system that has experienced semi-monotonic cooling prior to chilling; crystals entrained from a long-standing cumulate bed that were mechanically sorted in ascending magma may not reveal this history. Ragged old crystals rolling about in the system for untold numbers of flushing times record specious process times, telling more about the noise in the system than the life of typical, first generation crystallization processes. The most helpful process-related time scales are those that are known well and that bound or define the temporal style of the system. Perhaps the most valuable of these

  14. Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations

    International Nuclear Information System (INIS)

    Fulea, D.; Cosma, C.

    2006-01-01

    In order to apply the Monte Carlo simulation technique for usual radiological examinations we developed a Pc program, 'IradMed', written entirely in Java. The main purpose of this program is to compute the organ doses and the effective dose of patients, which are exposed at a X-ray beam having photon energies in 10 to 150 keV radiodiagnostic range. Three major radiological procedures are considered, namely mammography, radiography and CT. The fluoroscopy implies an irregular geometry and therefore it is neglected. Nevertheless, a gross estimation of patient doses can be made taking into account the fluoroscopy as being composed of several radiographic examinations applied in different anatomical regions. The interactions between radiation and matter are well-known, and the accuracy of the calculation is limited by the accuracy of the anatomical model used to describe actual patients and by characterisation of the radiation field applied. In this version of IradMed, it is assumed that the absorbed dose is equal with kerma for all tissues. No procedure has been used to take account of the finite range of the secondary electrons that are produced by photoelectric or Compton interactions. These ranges are small compared with the dimensions of the organs, and the absorbed dose will not change abruptly with distance except at boundary where composition and density change. However these boundary effects would have little effect in the determination of the average doses to almost all organs, except the active bone marrow which is treated separately. Another justification for this kerma approximation is the fact that the sum of all electron energies that exit the organ is statistically equal with the sum of all electron energies that enter in that particular organ. In this version of program, it is considered the following interactions: the Rayleigh scattering, the Compton scattering and the photoelectric effect. The Compton scattering is modeled by several methods which

  15. Exponentials and Laplace transforms on nonuniform time scales

    Science.gov (United States)

    Ortigueira, Manuel D.; Torres, Delfim F. M.; Trujillo, Juan J.

    2016-10-01

    We formulate a coherent approach to signals and systems theory on time scales. The two derivatives from the time-scale calculus are used, i.e., nabla (forward) and delta (backward), and the corresponding eigenfunctions, the so-called nabla and delta exponentials, computed. With these exponentials, two generalised discrete-time Laplace transforms are deduced and their properties studied. These transforms are compatible with the standard Laplace and Z transforms. They are used to study discrete-time linear systems defined by difference equations. These equations mimic the usual continuous-time equations that are uniformly approximated when the sampling interval becomes small. Impulse response and transfer function notions are introduced. This implies a unified mathematical framework that allows us to approximate the classic continuous-time case when the sampling rate is high or to obtain the standard discrete-time case, based on difference equations, when the time grid becomes uniform.

  16. Time-Scale and Time-Frequency Analyses of Irregularly Sampled Astronomical Time Series

    Directory of Open Access Journals (Sweden)

    S. Roques

    2005-09-01

    Full Text Available We evaluate the quality of spectral restoration in the case of irregular sampled signals in astronomy. We study in details a time-scale method leading to a global wavelet spectrum comparable to the Fourier period, and a time-frequency matching pursuit allowing us to identify the frequencies and to control the error propagation. In both cases, the signals are first resampled with a linear interpolation. Both results are compared with those obtained using Lomb's periodogram and using the weighted waveletZ-transform developed in astronomy for unevenly sampled variable stars observations. These approaches are applied to simulations and to light variations of four variable stars. This leads to the conclusion that the matching pursuit is more efficient for recovering the spectral contents of a pulsating star, even with a preliminary resampling. In particular, the results are almost independent of the quality of the initial irregular sampling.

  17. Microsecond time-scale kinetics of transient biochemical reactions

    NARCIS (Netherlands)

    Mitic, S.; Strampraad, M.J.F.; Hagen, W.R.; de Vries, S.

    2017-01-01

    To afford mechanistic studies in enzyme kinetics and protein folding in the microsecond time domain we have developed a continuous-flow microsecond time-scale mixing instrument with an unprecedented dead-time of 3.8 ± 0.3 μs. The instrument employs a micro-mixer with a mixing time of 2.7 μs

  18. Visual simultaneous localization and mapping (VSLAM) methods applied to indoor 3D topographical and radiological mapping in real-time

    International Nuclear Information System (INIS)

    Hautot, F.; Dubart, P.; Chagneau, B.; Bacri, C.O.; Abou-Khalil, R.

    2017-01-01

    New developments in the field of robotics and computer vision enable to merge sensors to allow fast real-time localization of radiological measurements in the space/volume with near real-time radioactive sources identification and characterization. These capabilities lead nuclear investigations to a more efficient way for operators' dosimetry evaluation, intervention scenarios and risks mitigation and simulations, such as accidents in unknown potentially contaminated areas or during dismantling operations. This paper will present new progresses in merging RGB-D camera based on SLAM (Simultaneous Localization and Mapping) systems and nuclear measurement in motion methods in order to detect, locate, and evaluate the activity of radioactive sources in 3-dimensions

  19. SU-D-209-03: Radiation Dose Reduction Using Real-Time Image Processing in Interventional Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Kanal, K; Moirano, J; Zamora, D; Stewart, B [University Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: To characterize changes in radiation dose after introducing a new real-time image processing technology in interventional radiology systems. Methods: Interventional radiology (IR) procedures are increasingly complex, at times requiring substantial time and radiation dose. The risk of inducing tissue reactions as well as long-term stochastic effects such as radiation-induced cancer is not trivial. To reduce this risk, IR systems are increasingly equipped with dose reduction technologies.Recently, ClarityIQ (Philips Healthcare) technology was installed in our existing neuroradiology IR (NIR) and vascular IR (VIR) suites respectively. ClarityIQ includes real-time image processing that reduces noise/artifacts, enhances images, and sharpens edges while also reducing radiation dose rates. We reviewed 412 NIR (175 pre- and 237 post-ClarityIQ) procedures and 329 VIR (156 preand 173 post-ClarityIQ) procedures performed at our institution pre- and post-ClarityIQ implementation. NIR procedures were primarily classified as interventional or diagnostic. VIR procedures included drain port, drain placement, tube change, mesenteric, and implanted venous procedures. Air Kerma (AK in units of mGy) was documented for all the cases using a commercial radiation exposure management system. Results: When considering all NIR procedures, median AK decreased from 1194 mGy to 561 mGy. When considering all VIR procedures, median AK decreased from 49 to 14 mGy. Both NIR and VIR exhibited a decrease in AK exceeding 50% after ClarityIQ implementation, a statistically significant (p<0.05) difference. Of the 5 most common VIR procedures, all median AK values decreased, but significance (p<0.05) was only reached in venous access (N=53), angio mesenteric (N=41), and drain placement procedures (N=31). Conclusion: ClarityIQ can reduce dose significantly for both NIR and VIR procedures. Image quality was not assessed in conjunction with the dose reduction.

  20. SU-D-209-03: Radiation Dose Reduction Using Real-Time Image Processing in Interventional Radiology

    International Nuclear Information System (INIS)

    Kanal, K; Moirano, J; Zamora, D; Stewart, B

    2016-01-01

    Purpose: To characterize changes in radiation dose after introducing a new real-time image processing technology in interventional radiology systems. Methods: Interventional radiology (IR) procedures are increasingly complex, at times requiring substantial time and radiation dose. The risk of inducing tissue reactions as well as long-term stochastic effects such as radiation-induced cancer is not trivial. To reduce this risk, IR systems are increasingly equipped with dose reduction technologies.Recently, ClarityIQ (Philips Healthcare) technology was installed in our existing neuroradiology IR (NIR) and vascular IR (VIR) suites respectively. ClarityIQ includes real-time image processing that reduces noise/artifacts, enhances images, and sharpens edges while also reducing radiation dose rates. We reviewed 412 NIR (175 pre- and 237 post-ClarityIQ) procedures and 329 VIR (156 preand 173 post-ClarityIQ) procedures performed at our institution pre- and post-ClarityIQ implementation. NIR procedures were primarily classified as interventional or diagnostic. VIR procedures included drain port, drain placement, tube change, mesenteric, and implanted venous procedures. Air Kerma (AK in units of mGy) was documented for all the cases using a commercial radiation exposure management system. Results: When considering all NIR procedures, median AK decreased from 1194 mGy to 561 mGy. When considering all VIR procedures, median AK decreased from 49 to 14 mGy. Both NIR and VIR exhibited a decrease in AK exceeding 50% after ClarityIQ implementation, a statistically significant (p<0.05) difference. Of the 5 most common VIR procedures, all median AK values decreased, but significance (p<0.05) was only reached in venous access (N=53), angio mesenteric (N=41), and drain placement procedures (N=31). Conclusion: ClarityIQ can reduce dose significantly for both NIR and VIR procedures. Image quality was not assessed in conjunction with the dose reduction.

  1. Time scale bias in erosion rates of glaciated landscapes.

    Science.gov (United States)

    Ganti, Vamsi; von Hagke, Christoph; Scherler, Dirk; Lamb, Michael P; Fischer, Woodward W; Avouac, Jean-Philippe

    2016-10-01

    Deciphering erosion rates over geologic time is fundamental for understanding the interplay between climate, tectonic, and erosional processes. Existing techniques integrate erosion over different time scales, and direct comparison of such rates is routinely done in earth science. On the basis of a global compilation, we show that erosion rate estimates in glaciated landscapes may be affected by a systematic averaging bias that produces higher estimated erosion rates toward the present, which do not reflect straightforward changes in erosion rates through time. This trend can result from a heavy-tailed distribution of erosional hiatuses (that is, time periods where no or relatively slow erosion occurs). We argue that such a distribution can result from the intermittency of erosional processes in glaciated landscapes that are tightly coupled to climate variability from decadal to millennial time scales. In contrast, we find no evidence for a time scale bias in spatially averaged erosion rates of landscapes dominated by river incision. We discuss the implications of our findings in the context of the proposed coupling between climate and tectonics, and interpreting erosion rate estimates with different averaging time scales through geologic time.

  2. Hydrodynamic time scales for intense laser-heated clusters

    International Nuclear Information System (INIS)

    Parra, Enrique; Alexeev, Ilya; Fan, Jingyun; Kim, Kiong Y.; McNaught, Stuart J.; Milchberg, Howard M.

    2003-01-01

    Measurements are presented of x-ray (>1.5 keV) and extreme ultraviolet (EUV, λ equal to 2-44 nm) emission from argon clusters irradiated with constant-energy (50 mJ), variable-width laser pulses ranging from 100 fs to 10 ns. The results for clusters can be understood in terms of two time scales: a short time scale for optimal resonant absorption at the critical-density layer in the expanding plasma, and a longer time scale for the plasma to drop below critical density. We present a one-dimensional hydrodynamic model of the intense laser-cluster interaction in which the laser field is treated self-consistently. We find that nonuniform expansion of the heated material results in long-time resonance of the laser field at the critical-density plasma layer. These simulations explain the dependence of generation efficiency on laser pulse width

  3. Ignition in net for different energy confinement time scalings

    International Nuclear Information System (INIS)

    Johner, J.; Prevot, F.

    1988-06-01

    A zero-dimensional profile dependent model is used to assess the feasibility of ignition in the extended version of NET. Five recent scalings for the energy confinement time (Goldston, Kaye All, Kaye Big, Shimomura-Odajima, Rebut-Lallia) are compared in the frame of two different scenarii, i.e., H-mode with a flat density profile or L-mode with a peaked density profile. For the flat density H-mode case, ignition is accessible with none of the scalings except Rebut-Lallia's. For the peaked density L-mode case, ignition is accessible with none of the scalings except Rebut-Lallia's. For the two Kaye's scalings, ignition is forbidden in H-mode even with the peaked density profile. For the Rebut-Lallia scaling, ignition is allowed in L-mode even with the flat density profile

  4. Deviations from uniform power law scaling in nonstationary time series

    Science.gov (United States)

    Viswanathan, G. M.; Peng, C. K.; Stanley, H. E.; Goldberger, A. L.

    1997-01-01

    A classic problem in physics is the analysis of highly nonstationary time series that typically exhibit long-range correlations. Here we test the hypothesis that the scaling properties of the dynamics of healthy physiological systems are more stable than those of pathological systems by studying beat-to-beat fluctuations in the human heart rate. We develop techniques based on the Fano factor and Allan factor functions, as well as on detrended fluctuation analysis, for quantifying deviations from uniform power-law scaling in nonstationary time series. By analyzing extremely long data sets of up to N = 10(5) beats for 11 healthy subjects, we find that the fluctuations in the heart rate scale approximately uniformly over several temporal orders of magnitude. By contrast, we find that in data sets of comparable length for 14 subjects with heart disease, the fluctuations grow erratically, indicating a loss of scaling stability.

  5. Length and time scales of atmospheric moisture recycling

    Directory of Open Access Journals (Sweden)

    R. J. van der Ent

    2011-03-01

    Full Text Available It is difficult to quantify the degree to which terrestrial evaporation supports the occurrence of precipitation within a certain study region (i.e. regional moisture recycling due to the scale- and shape-dependence of regional moisture recycling ratios. In this paper we present a novel approach to quantify the spatial and temporal scale of moisture recycling, independent of the size and shape of the region under study. In contrast to previous studies, which essentially used curve fitting, the scaling laws presented by us follow directly from the process equation. thus allowing a fair comparison between regions and seasons. The calculation is based on ERA-Interim reanalysis data for the period 1999 to 2008. It is shown that in the tropics or in mountainous terrain the length scale of recycling can be as low as 500 to 2000 km. In temperate climates the length scale is typically between 3000 to 5000 km whereas it amounts to more than 7000 km in desert areas. The time scale of recycling ranges from 3 to 20 days, with the exception of deserts, where it is much longer. The most distinct seasonal differences can be observed over the Northern Hemisphere: in winter, moisture recycling is insignificant, whereas in summer it plays a major role in the climate. The length and time scales of atmospheric moisture recycling can be useful metrics to quantify local climatic effects of land use change.

  6. Fractional dynamic calculus and fractional dynamic equations on time scales

    CERN Document Server

    Georgiev, Svetlin G

    2018-01-01

    Pedagogically organized, this monograph introduces fractional calculus and fractional dynamic equations on time scales in relation to mathematical physics applications and problems. Beginning with the definitions of forward and backward jump operators, the book builds from Stefan Hilger’s basic theories on time scales and examines recent developments within the field of fractional calculus and fractional equations. Useful tools are provided for solving differential and integral equations as well as various problems involving special functions of mathematical physics and their extensions and generalizations in one and more variables. Much discussion is devoted to Riemann-Liouville fractional dynamic equations and Caputo fractional dynamic equations.  Intended for use in the field and designed for students without an extensive mathematical background, this book is suitable for graduate courses and researchers looking for an introduction to fractional dynamic calculus and equations on time scales. .

  7. Time-dependent scaling patterns in high frequency financial data

    Science.gov (United States)

    Nava, Noemi; Di Matteo, Tiziana; Aste, Tomaso

    2016-10-01

    We measure the influence of different time-scales on the intraday dynamics of financial markets. This is obtained by decomposing financial time series into simple oscillations associated with distinct time-scales. We propose two new time-varying measures of complexity: 1) an amplitude scaling exponent and 2) an entropy-like measure. We apply these measures to intraday, 30-second sampled prices of various stock market indices. Our results reveal intraday trends where different time-horizons contribute with variable relative amplitudes over the course of the trading day. Our findings indicate that the time series we analysed have a non-stationary multifractal nature with predominantly persistent behaviour at the middle of the trading session and anti-persistent behaviour at the opening and at the closing of the session. We demonstrate that these patterns are statistically significant, robust, reproducible and characteristic of each stock market. We argue that any modelling, analytics or trading strategy must take into account these non-stationary intraday scaling patterns.

  8. Evaluation of Scaling Invariance Embedded in Short Time Series

    Science.gov (United States)

    Pan, Xue; Hou, Lei; Stephen, Mutua; Yang, Huijie; Zhu, Chenping

    2014-01-01

    Scaling invariance of time series has been making great contributions in diverse research fields. But how to evaluate scaling exponent from a real-world series is still an open problem. Finite length of time series may induce unacceptable fluctuation and bias to statistical quantities and consequent invalidation of currently used standard methods. In this paper a new concept called correlation-dependent balanced estimation of diffusion entropy is developed to evaluate scale-invariance in very short time series with length . Calculations with specified Hurst exponent values of show that by using the standard central moving average de-trending procedure this method can evaluate the scaling exponents for short time series with ignorable bias () and sharp confidential interval (standard deviation ). Considering the stride series from ten volunteers along an approximate oval path of a specified length, we observe that though the averages and deviations of scaling exponents are close, their evolutionary behaviors display rich patterns. It has potential use in analyzing physiological signals, detecting early warning signals, and so on. As an emphasis, the our core contribution is that by means of the proposed method one can estimate precisely shannon entropy from limited records. PMID:25549356

  9. Optimizing Travel Time to Outpatient Interventional Radiology Procedures in a Multi-Site Hospital System Using a Google Maps Application.

    Science.gov (United States)

    Mandel, Jacob E; Morel-Ovalle, Louis; Boas, Franz E; Ziv, Etay; Yarmohammadi, Hooman; Deipolyi, Amy; Mohabir, Heeralall R; Erinjeri, Joseph P

    2018-02-20

    The purpose of this study is to determine whether a custom Google Maps application can optimize site selection when scheduling outpatient interventional radiology (IR) procedures within a multi-site hospital system. The Google Maps for Business Application Programming Interface (API) was used to develop an internal web application that uses real-time traffic data to determine estimated travel time (ETT; minutes) and estimated travel distance (ETD; miles) from a patient's home to each a nearby IR facility in our hospital system. Hypothetical patient home addresses based on the 33 cities comprising our institution's catchment area were used to determine the optimal IR site for hypothetical patients traveling from each city based on real-time traffic conditions. For 10/33 (30%) cities, there was discordance between the optimal IR site based on ETT and the optimal IR site based on ETD at non-rush hour time or rush hour time. By choosing to travel to an IR site based on ETT rather than ETD, patients from discordant cities were predicted to save an average of 7.29 min during non-rush hour (p = 0.03), and 28.80 min during rush hour (p Google Maps application to schedule outpatients for IR procedures can effectively reduce patient travel time when more than one location providing IR procedures is available within the same hospital system.

  10. A study on the radiation and environmental safety -Development of a real-time radiological dose assessment system-

    Energy Technology Data Exchange (ETDEWEB)

    Han, Moon Heui; Lee, Yung Bok; Kim, Eun Han; Suh, Kyung Suk; Hwang, Won Tae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    The real-time dose assessment system under development has been updated and the technology for tracer experiment has been established. The calculation of external gamma dose is the most difficult and time-consuming part of the dose calculations. The characteristics of external gamma exposure have been investigated and the method for reducing the calculation time has been devised. The internal exposure via the ingestion of the contaminated foodstuffs is one of the important pathways to the total radiological exposure. In the emergency, it is necessary to take an action such like food ban to protect the internal exposure. An algorithm for the interface between the real-time system and the food chain model has been provided. The second field tracer experiment over flat terrain has been carried out on a plain in Iksan city in Junrabook-Do. Sequential tracer sampler which can be sampled the tracer gas over arbitrary 12 time interval has been designed and manufactured. SF{sub 6} has been used as the tracer gas and the sampled gas has been analysed by gas-chromatographer. 55 figs, 32 tabs, 65 refs. (Author).

  11. Scintigraphic determination of gastrointestinal transit times. A comparison with breath hydrogen and radiologic methods

    DEFF Research Database (Denmark)

    Madsen, J L; Larsen, N E; Hilsted, J

    1991-01-01

    A scintigraphic method for determination of gastrointestinal transit times was compared with the breath hydrogen test and a multiple-bolus, single-radiograph technique. A close temporal association was found between the caecal appearance of radioactivity and the onset of breath hydrogen excretion...... in eight healthy subjects. Neither mean small-intestinal nor mean orocaecal transit times of the radiolabelled marker were correlated with the magnitude of hydrogen peak, hydrogen peak time, or the area under hydrogen curve. No correlation was noted between whole-gut transit time of the radiolabelled...... marker and mean whole-gut transit time calculated from a 6-day administration of the radiopaque marker in 16 healthy subjects. The stool weight was inversely correlated with the mean colonic (r = -0.46, p = 0.009) and the mean whole-gut (r = -0.45, p = 0.011) transit times of the radiolabelled marker...

  12. Vibration amplitude rule study for rotor under large time scale

    International Nuclear Information System (INIS)

    Yang Xuan; Zuo Jianli; Duan Changcheng

    2014-01-01

    The rotor is an important part of the rotating machinery; its vibration performance is one of the important factors affecting the service life. This paper presents both theoretical analyses and experimental demonstrations of the vibration rule of the rotor under large time scales. The rule can be used for the service life estimation of the rotor. (authors)

  13. Multiple dynamical time-scales in networks with hierarchically ...

    Indian Academy of Sciences (India)

    Multiple dynamical time-scales in networks with hierarchically nested modular organization ... http://www.ias.ac.in/article/fulltext/pram/077/05/0833-0842 ... Many natural and engineered complex networks have intricate mesoscopic organization, e.g., the clustering of the constituent nodes into several communities or ...

  14. Gott time machines, BTZ black hole formation, and choptuik scaling

    Science.gov (United States)

    Birmingham; Sen

    2000-02-07

    We study the formation of Banados-Teitelboim-Zanelli black holes by the collision of point particles. It is shown that the Gott time machine, originally constructed for the case of vanishing cosmological constant, provides a precise mechanism for black hole formation. As a result, one obtains an exact analytic understanding of the Choptuik scaling.

  15. Speech Compensation for Time-Scale-Modified Auditory Feedback

    Science.gov (United States)

    Ogane, Rintaro; Honda, Masaaki

    2014-01-01

    Purpose: The purpose of this study was to examine speech compensation in response to time-scale-modified auditory feedback during the transition of the semivowel for a target utterance of /ija/. Method: Each utterance session consisted of 10 control trials in the normal feedback condition followed by 20 perturbed trials in the modified auditory…

  16. Wind power impacts and electricity storage - a time scale perspective

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Meibom, Peter

    2012-01-01

    technologies – batteries, flow batteries, compressed air energy storage, electrolysis combined with fuel cells, and electric vehicles – are moreover categorised with respect to the time scales at which they are suited to support wind power integration. While all of these technologies are assessed suitable...

  17. Time scales of coupled modes in the tropical climate system

    Science.gov (United States)

    An, S. I.; Bejarano, L.; Jin, F. F.

    2003-04-01

    Climate variability in the tropical Pacific has a rich frequency spectrum that partly results from coupled modes different time scales. We examined the contributions of the thermocline feedback (the vertical advection of anomalous subsurface temperature by the mean upwelling) and zonal advective feedback (the zonal advection of mean sea surface temperature by anomalous current) in determining the time scales of the coupled modes. Firstly, using a simple ocean model, we study the dependence of maximum amplitudes and locations of equatorial zonal current and thermocline on the time scales of the wind forcing. Then we examine in a linearized version of coupled Zebiak-Cane model the impacts of these feedbacks on the co-existence of leading coupled modes of different time scales. For slowly varying wind forcing, amplitudes of zonal currents are very weak and locate at western Pacific, whereas the thermocline response is strong. The zonal advective feedback thus tends but to be of secondly importance in a slow mode of interannual periodicity although it plays a dominating role in a fast coupled mode of near annual periodicity. The changes in the basic state of the coupled system can have significant impacts on the relative importance of the two main feedbacks and thus the periodicity and stability of the leading modes of the coupled tropical Pacific climate system.

  18. Exponential stability of dynamic equations on time scales

    Directory of Open Access Journals (Sweden)

    Raffoul Youssef N

    2005-01-01

    Full Text Available We investigate the exponential stability of the zero solution to a system of dynamic equations on time scales. We do this by defining appropriate Lyapunov-type functions and then formulate certain inequalities on these functions. Several examples are given.

  19. Decomposition of wind speed fluctuations at different time scales

    Indian Academy of Sciences (India)

    Understanding the inherent features of wind speed (variability on different time scales) has become critical for assured wind power availability, grid stability, and effective power management. The study utilizes the wavelet, autocorrelation, and FFT (fast Fourier transform) techniques to analyze and assimilate the fluctuating ...

  20. THEORETICAL REVIEW The Hippocampus, Time, and Memory Across Scales

    Science.gov (United States)

    Howard, Marc W.; Eichenbaum, Howard

    2014-01-01

    A wealth of experimental studies with animals have offered insights about how neural networks within the hippocampus support the temporal organization of memories. These studies have revealed the existence of “time cells” that encode moments in time, much as the well-known “place cells” map locations in space. Another line of work inspired by human behavioral studies suggests that episodic memories are mediated by a state of temporal context that changes gradually over long time scales, up to at least a few thousand seconds. In this view, the “mental time travel” hypothesized to support the experience of episodic memory corresponds to a “jump back in time” in which a previous state of temporal context is recovered. We suggest that these 2 sets of findings could be different facets of a representation of temporal history that maintains a record at the last few thousand seconds of experience. The ability to represent long time scales comes at the cost of discarding precise information about when a stimulus was experienced—this uncertainty becomes greater for events further in the past. We review recent computational work that describes a mechanism that could construct such a scale-invariant representation. Taken as a whole, this suggests the hippocampus plays its role in multiple aspects of cognition by representing events embedded in a general spatiotemporal context. The representation of internal time can be useful across nonhippocampal memory systems. PMID:23915126

  1. Time scale algorithm: Definition of ensemble time and possible uses of the Kalman filter

    Science.gov (United States)

    Tavella, Patrizia; Thomas, Claudine

    1990-01-01

    The comparative study of two time scale algorithms, devised to satisfy different but related requirements, is presented. They are ALGOS(BIPM), producing the international reference TAI at the Bureau International des Poids et Mesures, and AT1(NIST), generating the real-time time scale AT1 at the National Institute of Standards and Technology. In each case, the time scale is a weighted average of clock readings, but the weight determination and the frequency prediction are different because they are adapted to different purposes. The possibility of using a mathematical tool, such as the Kalman filter, together with the definition of the time scale as a weighted average, is also analyzed. Results obtained by simulation are presented.

  2. Effect of the Duration Time of a Nuclear Accident on Radiological Health Consequences

    Directory of Open Access Journals (Sweden)

    Hyojoon Jeong

    2014-03-01

    Full Text Available This study aimed to quantify the effect of duration time of a nuclear accident on the radiation dose of a densely populated area and the resulting acute health effects. In the case of nuclear accidents, the total emissions of radioactive materials can be classified into several categories. Therefore, the release information is very important for the assessment of risk to the public. We confirmed that when the duration time of the emissions are prolonged to 7 hours, the concentrations of radioactive substances in the ambient air are reduced by 50% compared to that when the duration time of emission is one hour. This means that the risk evaluation using only the first wind direction of an accident is very conservative, so it has to be used as a screening level for the risk assessment. Furthermore, it is judged that the proper control of the emission time of a nuclear accident can minimize the health effects on residents.

  3. Decoding the Mobility and Time Scales of Protein Loops.

    Science.gov (United States)

    Gu, Yina; Li, Da-Wei; Brüschweiler, Rafael

    2015-03-10

    The flexible nature of protein loops and the time scales of their dynamics are critical for many biologically important events at the molecular level, such as protein interaction and recognition processes. In order to obtain a predictive understanding of the dynamic properties of loops, 500 ns molecular dynamics (MD) computer simulations of 38 different proteins were performed and validated using NMR chemical shifts. A total of 169 loops were analyzed and classified into three types, namely fast loops with correlation times Web server (http://spin.ccic.ohio-state.edu/index.php/loop). The results demonstrate that loop dynamics with their time scales can be predicted rapidly with reasonable accuracy, which will allow the screening of average protein structures to help better understand the various roles loops can play in the context of protein-protein interactions and binding.

  4. Human learning: Power laws or multiple characteristic time scales?

    Directory of Open Access Journals (Sweden)

    Gottfried Mayer-Kress

    2006-09-01

    Full Text Available The central proposal of A. Newell and Rosenbloom (1981 was that the power law is the ubiquitous law of learning. This proposition is discussed in the context of the key factors that led to the acceptance of the power law as the function of learning. We then outline the principles of an epigenetic landscape framework for considering the role of the characteristic time scales of learning and an approach to system identification of the processes of performance dynamics. In this view, the change of performance over time is the product of a superposition of characteristic exponential time scales that reflect the influence of different processes. This theoretical approach can reproduce the traditional power law of practice – within the experimental resolution of performance data sets - but we hypothesize that this function may prove to be a special and perhaps idealized case of learning.

  5. Cognitive componets of speech at different time scales

    DEFF Research Database (Denmark)

    Feng, Ling; Hansen, Lars Kai

    2007-01-01

    that are essentially independent in a reasonable ensemble can be efficiently coded using a sparse independent component representation. The representations are indeed shown to be very similar between supervised learning (invoking cognitive activity) and unsupervised learning (statistical regularities), hence lending...... have earlier been revealed at multiple time scales corresponding to: phoneme, gender, height and speaker identity. We here show that the same simple unsupervised learning algorithm can detect these cues. Our basic features are 25-dimensional short time Mel-frequency weighted cepstral coefficients......Cognitive component analysis (COCA) is defined as unsupervised grouping of data leading to a group structure well aligned with that resulting from human cognitive activity. We focus here on speech at different time scales looking for possible hidden ‘cognitive structure’. Statistical regularities...

  6. Energy and time determine scaling in biological and computer designs

    Science.gov (United States)

    Bezerra, George; Edwards, Benjamin; Brown, James; Forrest, Stephanie

    2016-01-01

    Metabolic rate in animals and power consumption in computers are analogous quantities that scale similarly with size. We analyse vascular systems of mammals and on-chip networks of microprocessors, where natural selection and human engineering, respectively, have produced systems that minimize both energy dissipation and delivery times. Using a simple network model that simultaneously minimizes energy and time, our analysis explains empirically observed trends in the scaling of metabolic rate in mammals and power consumption and performance in microprocessors across several orders of magnitude in size. Just as the evolutionary transitions from unicellular to multicellular animals in biology are associated with shifts in metabolic scaling, our model suggests that the scaling of power and performance will change as computer designs transition to decentralized multi-core and distributed cyber-physical systems. More generally, a single energy–time minimization principle may govern the design of many complex systems that process energy, materials and information. This article is part of the themed issue ‘The major synthetic evolutionary transitions’. PMID:27431524

  7. Terrestrial carbon-nitrogen interactions across time-scales

    Science.gov (United States)

    Zaehle, Sönke; Sickel, Kerstin

    2017-04-01

    Through its role in forming amino acids, nitrogen (N) plays a fundamental role in terrestrial biogeochemistry, affecting for instance the photosynthetic rate of a leaf, and the amount of leaf area of a plant; with further consequences for quasi instantaneous terrestrial biophysical properties and fluxes. Because of the high energy requirements of transforming atmospheric N2 to biologically available form, N is generally thought to be limiting terrestrial productivity. Experimental evidence and modelling studies suggest that in temperate and boreal ecosystems, this N-"limitation" affects plant production at scales from days to decades, and potentially beyond. Whether these interactions play a role at longer timescales, such as during the transition from the last glacial maximum to the holocene, is currently unclear. To address this question, we present results from a 22000 years long simulation with dynamic global vegetation model including a comprehensive treatment of the terrestrial carbon and nitrogen balance and their interactions (using the OCN-DGVM) driven by monthly, transient climate forcing obtained from the CESM climate model (TRACE). OCN couples carbon and nitrogen processes at the time-scale of hours, but simulates a comprehensive nitrogen balance as well as vegetation dynamics with time-scales of centuries and beyond. We investigate in particular, whether (and at with time scale) carbon-nitrogen interactions cause important lags in the response of the terrestrial biosphere to changed climate, and which processes (such as altered N inputs from fixation or altered losses through leaching and denitrification) contribute to these lags.

  8. Real-time analyses and precautionary action. The program system for assessing and limiting radiological consequences

    International Nuclear Information System (INIS)

    Jacob, P.; Gregor, J.

    1993-01-01

    AUTOPARK is a mostly automatically running program system which during intensive operation of IMIS provides large-scale assessments of nuclide-specific contamination of soils and 20 plants. Based on calculation results, the potential radiation exposure of the population to ten relevant radionuclides is assessed; contaminations of food to be expected are forecast, and the effects of the emergency measures 'recommendation to stay indoors' and 'marketing ban on higher contaminated food' are investigated. DIAPARK is a dialogue-controlled program system which, on the basis of the depositions on soil and plants calculated by AUTOPARK, enables the study of specific questions, such as the effects of changed feed compositions for useful animals. The DOSISPARK program was developed to assess potential radiation exposure of the population by means of meaasuring data acquired during normal operation of IMIS. (orig./DG) [de

  9. Earthquake magnitude time series: scaling behavior of visibility networks

    Science.gov (United States)

    Aguilar-San Juan, B.; Guzmán-Vargas, L.

    2013-11-01

    We present a statistical analysis of earthquake magnitude sequences in terms of the visibility graph method. Magnitude time series from Italy, Southern California, and Mexico are transformed into networks and some organizational graph properties are discussed. Connectivities are characterized by a scale-free distribution with a noticeable effect for large scales due to either the presence or the lack of large events. Also, a scaling behavior is observed between different node measures like betweenness centrality, clustering coefficient, nearest neighbor connectivity, and earthquake magnitude. Moreover, parameters which quantify the difference between forward and backward links, are proposed to evaluate the asymmetry of visibility attachment mechanism. Our results show an alternating average behavior of these parameters as earthquake magnitude changes. Finally, we evaluate the effects of reducing temporal and spatial windows of observation upon visibility network properties for main-shocks.

  10. Radiology fundamentals

    CERN Document Server

    Singh, Harjit

    2011-01-01

    ""Radiology Fundamentals"" is a concise introduction to the dynamic field of radiology for medical students, non-radiology house staff, physician assistants, nurse practitioners, radiology assistants, and other allied health professionals. The goal of the book is to provide readers with general examples and brief discussions of basic radiographic principles and to serve as a curriculum guide, supplementing a radiology education and providing a solid foundation for further learning. Introductory chapters provide readers with the fundamental scientific concepts underlying the medical use of imag

  11. Reconstructions of solar irradiance on centennial time scales

    Science.gov (United States)

    Krivova, Natalie; Solanki, Sami K.; Dasi Espuig, Maria; Kok Leng, Yeo

    Solar irradiance is the main external source of energy to Earth's climate system. The record of direct measurements covering less than 40 years is too short to study solar influence on Earth's climate, which calls for reconstructions of solar irradiance into the past with the help of appropriate models. An obvious requirement to a competitive model is its ability to reproduce observed irradiance changes, and a successful example of such a model is presented by the SATIRE family of models. As most state-of-the-art models, SATIRE assumes that irradiance changes on time scales longer than approximately a day are caused by the evolving distribution of dark and bright magnetic features on the solar surface. The surface coverage by such features as a function of time is derived from solar observations. The choice of these depends on the time scale in question. Most accurate is the version of the model that employs full-disc spatially-resolved solar magnetograms and reproduces over 90% of the measured irradiance variation, including the overall decreasing trend in the total solar irradiance over the last four cycles. Since such magnetograms are only available for about four decades, reconstructions on time scales of centuries have to rely on disc-integrated proxies of solar magnetic activity, such as sunspot areas and numbers. Employing a surface flux transport model and sunspot observations as input, we have being able to produce synthetic magnetograms since 1700. This improves the temporal resolution of the irradiance reconstructions on centennial time scales. The most critical aspect of such reconstructions remains the uncertainty in the magnitude of the secular change.

  12. Time scale of diffusion in molecular and cellular biology

    International Nuclear Information System (INIS)

    Holcman, D; Schuss, Z

    2014-01-01

    Diffusion is the driver of critical biological processes in cellular and molecular biology. The diverse temporal scales of cellular function are determined by vastly diverse spatial scales in most biophysical processes. The latter are due, among others, to small binding sites inside or on the cell membrane or to narrow passages between large cellular compartments. The great disparity in scales is at the root of the difficulty in quantifying cell function from molecular dynamics and from simulations. The coarse-grained time scale of cellular function is determined from molecular diffusion by the mean first passage time of molecular Brownian motion to a small targets or through narrow passages. The narrow escape theory (NET) concerns this issue. The NET is ubiquitous in molecular and cellular biology and is manifested, among others, in chemical reactions, in the calculation of the effective diffusion coefficient of receptors diffusing on a neuronal cell membrane strewn with obstacles, in the quantification of the early steps of viral trafficking, in the regulation of diffusion between the mother and daughter cells during cell division, and many other cases. Brownian trajectories can represent the motion of a molecule, a protein, an ion in solution, a receptor in a cell or on its membrane, and many other biochemical processes. The small target can represent a binding site or an ionic channel, a hidden active site embedded in a complex protein structure, a receptor for a neurotransmitter on the membrane of a neuron, and so on. The mean time to attach to a receptor or activator determines diffusion fluxes that are key regulators of cell function. This review describes physical models of various subcellular microdomains, in which the NET coarse-grains the molecular scale to a higher cellular-level, thus clarifying the role of cell geometry in determining subcellular function. (topical review)

  13. Bioremediation of Petroleum and Radiological Contaminated Soils at the Savannah River Site: Laboratory to Field Scale Applications

    Energy Technology Data Exchange (ETDEWEB)

    BRIGMON, ROBINL.

    2004-06-07

    In the process of Savannah River Site (SRS) operations limited amounts of waste are generated containing petroleum, and radiological contaminated soils. Currently, this combination of radiological and petroleum contaminated waste does not have an immediate disposal route and is being stored in low activity vaults. SRS developed and implemented a successful plan for clean up of the petroleum portion of the soils in situ using simple, inexpensive, bioreactor technology. Treatment in a bioreactor removes the petroleum contamination from the soil without spreading radiological contamination to the environment. This bioreactor uses the bioventing process and bioaugmentation or the addition of the select hydrocarbon degrading bacteria. Oxygen is usually the initial rate-limiting factor in the biodegradation of petroleum hydrocarbons. Using the bioventing process allowed control of the supply of nutrients and moisture based on petroleum contamination concentrations and soil type. The results of this work have proven to be a safe and cost-effective means of cleaning up low level radiological and petroleum-contaminated soil. Many of the other elements of the bioreactor design were developed or enhanced during the demonstration of a ''biopile'' to treat the soils beneath a Polish oil refinery's waste disposal lagoons. Aerobic microorganisms were isolated from the aged refinery's acidic sludge contaminated with polycyclic aromatic hydrocarbons (PAHs). Twelve hydrocarbon-degrading bacteria were isolated from the sludge. The predominant PAH degraders were tentatively identified as Achromobacter, Pseudomonas Burkholderia, and Sphingomonas spp. Several Ralstonia spp were also isolated that produce biosurfactants. Biosurfactants can enhance bioremediation by increasing the bioavailability of hydrophobic contaminants including hydrocarbons. The results indicated that the diversity of acid-tolerant PAH-degrading microorganisms in acidic oil wastes may

  14. Cell assemblies at multiple time scales with arbitrary lag constellations.

    Science.gov (United States)

    Russo, Eleonora; Durstewitz, Daniel

    2017-01-11

    Hebb's idea of a cell assembly as the fundamental unit of neural information processing has dominated neuroscience like no other theoretical concept within the past 60 years. A range of different physiological phenomena, from precisely synchronized spiking to broadly simultaneous rate increases, has been subsumed under this term. Yet progress in this area is hampered by the lack of statistical tools that would enable to extract assemblies with arbitrary constellations of time lags, and at multiple temporal scales, partly due to the severe computational burden. Here we present such a unifying methodological and conceptual framework which detects assembly structure at many different time scales, levels of precision, and with arbitrary internal organization. Applying this methodology to multiple single unit recordings from various cortical areas, we find that there is no universal cortical coding scheme, but that assembly structure and precision significantly depends on the brain area recorded and ongoing task demands.

  15. The fission time scale measured with an atomic clock

    NARCIS (Netherlands)

    Kravchuk, VL; Wilschut, HW; Hunyadi, M; Kopecky, S; Lohner, H; Rogachevskiy, A; Siemssen, RH; Krasznahorkay, A; Hamilton, JH; Ramayya, AV; Carter, HK

    2003-01-01

    We present a new direct method of measuring the fission absolute time scale using an atomic clock based on the lifetime of a vacancy in the atomic K-shell. We studied the reaction Ne-20 + Th-232 -> O-16 + U-236* at 30 MeV/u. The excitation energy of about 115 MeV in such a reaction is in the range

  16. On transport phenomena and equilibration time scales in thermodenuders

    Directory of Open Access Journals (Sweden)

    R. Saleh

    2011-03-01

    Full Text Available This paper presents a theoretical and experimental investigation of thermodenuders that addresses two controversial issues: (1 equilibration time scales and (2 the need for an activated carbon (AC denuder in the cooling section. We describe a plug flow model for transport phenomena in a TD, which can be used to simulate the rate of vapor build-up in the gas phase and the corresponding change in particle size distribution. Model simulations were found to have excellent agreement with experiments performed with pure and mixed dicarboxylic acid aerosols. Both simulations and experiments showed that the aerosols approached equilibrium within reasonable residence times (15 s–30 s for aerosol concentrations and size distributions typical for laboratory measurements, and that volatility studies at sufficiently high aerosol loadings, therefore, need not resort to kinetic models for inference of thermodynamic properties. However, for size distributions relevant for ambient aerosols, equilibration time scales were much larger than residence times available with current TD designs. We have also performed dimensional analysis on the problem of equilibration in TDs, and derived a dimensionless equilibration parameter which can be used to determine the residence time needed for an aerosol of given size distribution and kinetic properties to approach equilibrium. It is also shown theoretically and empirically that aerosol volatility has no effect on the equilibration time scales. Model simulations and experiments showed that with aerosol size distributions relevant to both ambient and laboratory measurements re-condensation in the cooling section, with and without an AC denuder, was negligible. Thus, there is no significant benefit in using an AC denuder in the cooling section. Due to the risk of stripping volatile material from the aerosol, the use of AC denuders in the cooling section should be avoided. Finally, we present a rationale for why ΔC is

  17. Biogenic Calcium Phosphate Transformation in Soils over Millennium Time Scales

    Energy Technology Data Exchange (ETDEWEB)

    Sato, S.; Neves, E; Solomon, D; Liang, B; Lehmann, J

    2009-01-01

    Changes in bioavailability of phosphorus (P) during pedogenesis and ecosystem development have been shown for geogenic calcium phosphate (Ca-P). However, very little is known about long-term changes of biogenic Ca-P in soil. Long-term transformation characteristics of biogenic Ca-P were examined using anthropogenic soils along a chronosequence from centennial to millennial time scales. Phosphorus fractionation of Anthrosols resulted in overall consistency with the Walker and Syers model of geogenic Ca-P transformation during pedogenesis. The biogenic Ca-P (e.g., animal and fish bones) disappeared to 3% of total P within the first ca. 2,000 years of soil development. This change concurred with increases in P adsorbed on metal-oxides surfaces, organic P, and occluded P at different pedogenic time. Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy revealed that the crystalline and therefore thermodynamically most stable biogenic Ca-P was transformed into more soluble forms of Ca-P over time. While crystalline hydroxyapatite (34% of total P) dominated Ca-P species after about 600-1,000 years, {Beta}-tricalcium phosphate increased to 16% of total P after 900-1,100 years, after which both Ca-P species disappeared. Iron-associated P was observable concurrently with Ca-P disappearance. Soluble P and organic P determined by XANES maintained relatively constant (58-65%) across the time scale studied. Conclusions - Disappearance of crystalline biogenic Ca-P on a time scale of a few thousand years appears to be ten times faster than that of geogenic Ca-P.

  18. Diffusion time scales and accretion in the sun

    International Nuclear Information System (INIS)

    Michaud, G.

    1977-01-01

    It is thought that surface abundances in the Sun could be due largely to accretion either of comets or grains, and it has been suggested that if surface convection zones were smaller than is usually indicated by model calculations, accretion would be especially important. Unless the zone immediately below the surface convection zone is sufficiently stable for diffusion to be important, other transport processes, such as turbulence and meridional circulation, more efficient than diffusion, will tend to homogenise the Sun. Diffusion is the slowest of the transport processes and will become important when other transport processes become inoperative. Using diffusion theory the minimum mass of the convection zone can be determined in order that transport processes at the bottom of the zone are not to influence abundances in the convection zone. If diffusion time scales are shorter than the life of the star (Sun) diffusion will modify the abundances in the convection zone. The mass in the convection zone for which diffusion time scales are equal to the life of the star on the main sequence then determines the minimum mass in the convection zone that justifies neglect of transport processes at the bottom of the convection zone. It is calculated here that, for the Sun, this mass is between 3 x 10 -3 and 10 -2 solar mass, and a general explosion is derived for the diffusion time scale as a function of the mass of the convection zone. (U.K.)

  19. Backpropagation and ordered derivatives in the time scales calculus.

    Science.gov (United States)

    Seiffertt, John; Wunsch, Donald C

    2010-08-01

    Backpropagation is the most widely used neural network learning technique. It is based on the mathematical notion of an ordered derivative. In this paper, we present a formulation of ordered derivatives and the backpropagation training algorithm using the important emerging area of mathematics known as the time scales calculus. This calculus, with its potential for application to a wide variety of inter-disciplinary problems, is becoming a key area of mathematics. It is capable of unifying continuous and discrete analysis within one coherent theoretical framework. Using this calculus, we present here a generalization of backpropagation which is appropriate for cases beyond the specifically continuous or discrete. We develop a new multivariate chain rule of this calculus, define ordered derivatives on time scales, prove a key theorem about them, and derive the backpropagation weight update equations for a feedforward multilayer neural network architecture. By drawing together the time scales calculus and the area of neural network learning, we present the first connection of two major fields of research.

  20. Radiology illustrated. Pediatric radiology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In-One (ed.) [Seoul National Univ. College of Medicine (Korea, Republic of). Dept. of Radiology

    2014-11-01

    Depicts characteristic imaging findings of common and uncommon diseases in the pediatric age group. Will serve as an ideal diagnostic reference in daily practice. Offers an excellent teaching aid, with numerous high-quality illustrations. This case-based atlas presents images depicting the findings typically observed when imaging a variety of common and uncommon diseases in the pediatric age group. The cases are organized according to anatomic region, covering disorders of the brain, spinal cord, head and neck, chest, cardiovascular system, gastrointestinal system, genitourinary system, and musculoskeletal system. Cases are presented in a form resembling teaching files, and the images are accompanied by concise informative text. The goal is to provide a diagnostic reference suitable for use in daily routine by both practicing radiologists and radiology residents or fellows. The atlas will also serve as a teaching aide and a study resource, and will offer pediatricians and surgeons guidance on the clinical applications of pediatric imaging.

  1. Radiology illustrated. Pediatric radiology

    International Nuclear Information System (INIS)

    Kim, In-One

    2014-01-01

    Depicts characteristic imaging findings of common and uncommon diseases in the pediatric age group. Will serve as an ideal diagnostic reference in daily practice. Offers an excellent teaching aid, with numerous high-quality illustrations. This case-based atlas presents images depicting the findings typically observed when imaging a variety of common and uncommon diseases in the pediatric age group. The cases are organized according to anatomic region, covering disorders of the brain, spinal cord, head and neck, chest, cardiovascular system, gastrointestinal system, genitourinary system, and musculoskeletal system. Cases are presented in a form resembling teaching files, and the images are accompanied by concise informative text. The goal is to provide a diagnostic reference suitable for use in daily routine by both practicing radiologists and radiology residents or fellows. The atlas will also serve as a teaching aide and a study resource, and will offer pediatricians and surgeons guidance on the clinical applications of pediatric imaging.

  2. Deep-time moles: art and archiving for an uncertain radiological future

    Science.gov (United States)

    Griffiths, Dave; Illingworth, Samuel; Girling, Matt

    2017-04-01

    This paper will present Deep Field [UnclearZine], a 2016 art-science project conducted at Mol and Dessel, two neighbouring rural villages co-existing with sites for planned geological nuclear-waste disposal in eastern Belgium. Dave Griffiths produced a microfiche publication that probes and narrates the scientific testing and politics of decision-making surrounding controversial ONDRAF-NIRAS (Belgian National Agency for Radioactive Waste and Enriched Fissile Materials) projects - at CatA, a tumulus for encasing low-level waste, and HADES, a lab investigating the feasibility and safety-case for deep-time geo-burial of high-level waste in clay strata. Griffiths' field work used qualitative and experiential methods such as ethnographic interviews with state scientists and independent monitoring groups, photographic derive, and sound recording, to sense a wider Anthropogenic narrative of energy production, mineral extraction and terrorist threat. Data were then remixed through narrative responses by scientist-poet Dr Sam Illingworth (Manchester Metropolitan University) and DIY-comix artist Matt Girling. Through experimenting with archaic analogue film technology, Griffiths collaged and miniaturised content to produce an edition of microfiches that have been distributed to zine libraries internationally. This subcultural format attempts to translate the past, present and future history of the repositories as folkloric sites of conflict, complexity and unknowing, for the benefit of a far-future readership. The paper will discuss the contemporary context of epistemological uncertainty around the survival and reception of crucial nuclear-security information in the face of inevitable material, linguistic and political ruination. We suggest that place-markers, as monumental semiotic warnings to the future, along with digital archives, might also be augmented by decentralised analogue fragments that promote ongoing memorialisation of nuclear-heritage sites through

  3. Atomistic simulations of graphite etching at realistic time scales.

    Science.gov (United States)

    Aussems, D U B; Bal, K M; Morgan, T W; van de Sanden, M C M; Neyts, E C

    2017-10-01

    Hydrogen-graphite interactions are relevant to a wide variety of applications, ranging from astrophysics to fusion devices and nano-electronics. In order to shed light on these interactions, atomistic simulation using Molecular Dynamics (MD) has been shown to be an invaluable tool. It suffers, however, from severe time-scale limitations. In this work we apply the recently developed Collective Variable-Driven Hyperdynamics (CVHD) method to hydrogen etching of graphite for varying inter-impact times up to a realistic value of 1 ms, which corresponds to a flux of ∼10 20 m -2 s -1 . The results show that the erosion yield, hydrogen surface coverage and species distribution are significantly affected by the time between impacts. This can be explained by the higher probability of C-C bond breaking due to the prolonged exposure to thermal stress and the subsequent transition from ion- to thermal-induced etching. This latter regime of thermal-induced etching - chemical erosion - is here accessed for the first time using atomistic simulations. In conclusion, this study demonstrates that accounting for long time-scales significantly affects ion bombardment simulations and should not be neglected in a wide range of conditions, in contrast to what is typically assumed.

  4. Stability theory for dynamic equations on time scales

    CERN Document Server

    Martynyuk, Anatoly A

    2016-01-01

    This monograph is a first in the world to present three approaches for stability analysis of solutions of dynamic equations. The first approach is based on the application of dynamic integral inequalities and the fundamental matrix of solutions of linear approximation of dynamic equations. The second is based on the generalization of the direct Lyapunovs method for equations on time scales, using scalar, vector and matrix-valued auxiliary functions. The third approach is the application of auxiliary functions (scalar, vector, or matrix-valued ones) in combination with differential dynamic inequalities. This is an alternative comparison method, developed for time continuous and time discrete systems. In recent decades, automatic control theory in the study of air- and spacecraft dynamics and in other areas of modern applied mathematics has encountered problems in the analysis of the behavior of solutions of time continuous-discrete linear and/or nonlinear equations of perturbed motion. In the book “Men of Ma...

  5. Radiological transportation emergency response training course funding and timing in the southern states

    International Nuclear Information System (INIS)

    1991-10-01

    The following is a review of the enabling statutes of 16 southern states regarding training for personnel preparing for or responding to a transportation-related emergency involving highway route-controlled quantities of spent fuel and high-level radioactive waste. This report outlines the funding sources and procedures for administering funds for programs attended by state and local officials. Additionally, the report outlines the views of emergency response officials in the southem states concerning the timing and administration of future federal assistance to be provided under section 180(c) of the Nuclear Waste Policy Amendments Act. Under section 180(c) of the Nuclear Waste Policy Amendments Act of 1987, the US Department of Energy (DOE) is required to provide technical assistance and funds to states for training public safety officials of appropriate units of local government and Indian tribes when spent nuclear fuel or high-level radioactive waste is transported through their jurisdictions. The Comprehensive Cooperative Agreement (CCA) is the primary funding mechanism for federal assistance to states for the development of their overall emergency management capabilities. FEMA supports 12 separate emergency management programs including the Emergency Management Training program (EMT). This program provides funds for emergency management training and technical assistance to states for unique state training needs. Funds may be used for instructors, students and other related costs

  6. Scale and time dependence of serial correlations in word-length time series of written texts

    Science.gov (United States)

    Rodriguez, E.; Aguilar-Cornejo, M.; Femat, R.; Alvarez-Ramirez, J.

    2014-11-01

    This work considered the quantitative analysis of large written texts. To this end, the text was converted into a time series by taking the sequence of word lengths. The detrended fluctuation analysis (DFA) was used for characterizing long-range serial correlations of the time series. To this end, the DFA was implemented within a rolling window framework for estimating the variations of correlations, quantified in terms of the scaling exponent, strength along the text. Also, a filtering derivative was used to compute the dependence of the scaling exponent relative to the scale. The analysis was applied to three famous English-written literary narrations; namely, Alice in Wonderland (by Lewis Carrol), Dracula (by Bram Stoker) and Sense and Sensibility (by Jane Austen). The results showed that high correlations appear for scales of about 50-200 words, suggesting that at these scales the text contains the stronger coherence. The scaling exponent was not constant along the text, showing important variations with apparent cyclical behavior. An interesting coincidence between the scaling exponent variations and changes in narrative units (e.g., chapters) was found. This suggests that the scaling exponent obtained from the DFA is able to detect changes in narration structure as expressed by the usage of words of different lengths.

  7. Predictability of 2-m temperature across space and time scales

    Science.gov (United States)

    Haiden, Thomas; Ben Bouallegue, Zied

    2017-04-01

    In the extra-tropics, 2-m temperature is arguably one of the most important parameters provided by weather forecasts. Although the skill of 2-m temperature forecasts from numerical weather prediction (NWP) models is slowly increasing, major issues remain. One of the main sources of uncertainty in the short range relates to difficulties in predicting the amount of vertical mixing in very stable boundary layers and associated uncertainties in the low cloudiness forecast. During the convective season, uncertainties in the timing and location of precipitation limit 2-m temperature forecast skill. Here we evaluate NWP model output from the TIGGE dataset against global SYNOP observations to evaluate the current level of 2-m temperature skill as a function of spatial and temporal scale for both deterministic and probabilistic forecasts. By comparing different types of verification metrics such as the generalized discrimination score, anomaly correlation, root mean square error, and mean error we can quantify predictability separately from representativeness errors and conditional biases. Spatial aggregation from the grid-box to the synoptic scale is performed to assess the contribution of synoptic-scale uncertainty on the 2-m temperature error at different lead times from the short range through the medium and extended range. Results allow inferences to be made about possible future improvements in the 2-m temperature forecast associated with improved model physics and spatial resolution.

  8. Impact of a PACS/RIS-integrated speech recognition system on radiology reporting time and report availability

    International Nuclear Information System (INIS)

    Trumm, C.G.; Glaser, C.; Paasche, V.; Kuettner, B.; Francke, M.; Nissen-Meyer, S.; Reiser, M.; Crispin, A.; Popp, P.

    2006-01-01

    Purpose: Quantification of the impact of a PACS/RIS-integrated speech recognition system (SRS) on the time expenditure for radiology reporting and on hospital-wide report availability (RA) in a university institution. Material and Methods: In a prospective pilot study, the following parameters were assessed for 669 radiographic examinations (CR): 1. time requirement per report dictation (TED: dictation time (s)/number of images [examination] x number of words [report]) with either a combination of PACS/tape-based dictation (TD: analog dictation device/minicassette/transcription) or PACS/RIS/speech recognition system (RR: remote recognition/transcription and OR: online recognition/self-correction by radiologist), respectively, and 2. the Report Turnaround Time (RTT) as the time interval from the entry of the first image into the PACS to the available RIS/HIS report. Two equal time periods were chosen retrospectively from the RIS database: 11/2002-2/2003 (only TD) and 11/2003-2/2004 (only RR or OR with speech recognition system [SRS]). The midterm (≥24 h, 24 h intervals) and short-term (< 24 h, 1 h intervals), RA after examination completion were calculated for all modalities and for Cr, CT, MR and XA/DS separately. The relative increase in the mid-term RA (RIMRA: related to total number of examinations in each time period) and increase in the short-term RA (ISRA: ratio of available reports during the 1st to 24th hour) were calculated. Results: Prospectively, there was a significant difference between TD/RR/OR (n=151/257/261) regarding mean TED (0.44/0.54/0.62 s [per word and image]) and mean RTT (10.47/6.65/1.27 h), respectively. Retrospectively, 37 898/39 680 reports were computed from the RIS database for the time periods of 11/2002-2/2003 and 11/2003-2/2004. For CR/CT there was a shift of the short-term RA to the first 6 hours after examination completion (mean cumulative RA 20% higher) with a more than three-fold increase in the total number of available

  9. [Impact of a PACS/RIS-integrated speech recognition system on radiology reporting time and report availability].

    Science.gov (United States)

    Trumm, C G; Glaser, C; Paasche, V; Crispin, A; Popp, P; Küttner, B; Francke, M; Nissen-Meyer, S; Reiser, M

    2006-04-01

    Quantification of the impact of a PACS/RIS-integrated speech recognition system (SRS) on the time expenditure for radiology reporting and on hospital-wide report availability (RA) in a university institution. In a prospective pilot study, the following parameters were assessed for 669 radiographic examinations (CR): 1. time requirement per report dictation (TED: dictation time (s)/number of images [examination] x number of words [report]) with either a combination of PACS/tape-based dictation (TD: analog dictation device/mini-cassette/transcription) or PACS/RIS/speech recognition system (RR: remote recognition/transcription and OR: online recognition/self-correction by radiologist), respectively, and 2. the Report Turnaround Time (RTT) as the time interval from the entry of the first image into the PACS to the available RIS/HIS report. Two equal time periods were chosen retrospectively from the RIS database: 11/2002 - 2/2003 (only TD) and 11/2003 - 2/2004 (only RR or OR with speech recognition system [SRS]). The mid-term (> or = 24 h, 24 h intervals) and short-term (reports during the 1st to 24th hour) were calculated. Prospectively, there was a significant difference between TD/RR/OR (n = 151/257/261) regarding mean TED (0.44/0.54/0.62 s [per word and image]) and mean RTT (10.47/6.65/1.27 h), respectively. Retrospectively, 37 898/39 680 reports were computed from the RIS database for the time periods of 11/2002 - 2/2003 and 11/2003 - 2/2004. For CR/CT there was a shift of the short-term RA to the first 6 hours after examination completion (mean cumulative RA 20 % higher) with a more than three-fold increase in the total number of available reports within 24 hours (all modalities). The RIMRA for CR/CT/MR was 3.1/5.8/4.0 in the first 24 hours, and 2.0 for XA/DS in the second 24-hour interval. In comparison to tape-based dictation, an SRS results in a significantly higher primary time expenditure and a modified report dictation workflow. In a university institution

  10. The Role of Time-Scales in Socio-hydrology

    Science.gov (United States)

    Blöschl, Günter; Sivapalan, Murugesu

    2016-04-01

    Much of the interest in hydrological modeling in the past decades revolved around resolving spatial variability. With the rapid changes brought about by human impacts on the hydrologic cycle, there is now an increasing need to refocus on time dependency. We present a co-evolutionary view of hydrologic systems, in which every part of the system including human systems, co-evolve, albeit at different rates. The resulting coupled human-nature system is framed as a dynamical system, characterized by interactions of fast and slow time scales and feedbacks between environmental and social processes. This gives rise to emergent phenomena such as the levee effect, adaptation to change and system collapse due to resource depletion. Changing human values play a key role in the emergence of these phenomena and should therefore be considered as internal to the system in a dynamic way. The co-evolutionary approach differs from the traditional view of water resource systems analysis as it allows for path dependence, multiple equilibria, lock-in situations and emergent phenomena. The approach may assist strategic water management for long time scales through facilitating stakeholder participation, exploring the possibility space of alternative futures, and helping to synthesise the observed dynamics of different case studies. Future research opportunities include the study of how changes in human values are connected to human-water interactions, historical analyses of trajectories of system co-evolution in individual places and comparative analyses of contrasting human-water systems in different climate and socio-economic settings. Reference Sivapalan, M. and G. Blöschl (2015) Time scale interactions and the coevolution of humans and water. Water Resour. Res., 51, 6988-7022, doi:10.1002/2015WR017896.

  11. Multi-Scale Dissemination of Time Series Data

    DEFF Research Database (Denmark)

    Guo, Qingsong; Zhou, Yongluan; Su, Li

    2013-01-01

    In this paper, we consider the problem of continuous dissemination of time series data, such as sensor measurements, to a large number of subscribers. These subscribers fall into multiple subscription levels, where each subscription level is specified by the bandwidth constraint of a subscriber......, which is an abstract indicator for both the physical limits and the amount of data that the subscriber would like to handle. To handle this problem, we propose a system framework for multi-scale time series data dissemination that employs a typical tree-based dissemination network and existing time...... to optimize the average accuracies of the data received by all subscribers within the dissemination network. Finally, we have conducted extensive experiments to study the performance of the algorithms....

  12. Decay of surface nanostructures via long-time-scale dynamics

    International Nuclear Information System (INIS)

    Voter, A.F.; Stanciu, N.

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have developed a new approach for extending the time scale of molecular dynamics simulations. For infrequent-event systems, the category that includes most diffusive events in the solid phase, this hyperdynamics method can extend the simulation time by a few orders of magnitude compared to direct molecular dynamics. The trajectory is run on a potential surface that has been biased to raise the energy in the potential basins without affecting the transition state region. The method is described and applied to surface and bulk diffusion processes, achieving microsecond and millisecond simulation times. The authors have also developed a new parallel computing method that is efficient for small system sizes. The combination of the hyperdynamics with this parallel replica dynamics looks promising as a general materials simulation tool

  13. Digital radiology

    International Nuclear Information System (INIS)

    Dallas, W.J.

    1990-01-01

    Radiology is vital to the life-saving efforts of surgeons and other physicians, but precious time can be lost generating the images and transferring them to and from the operating room. Furthermore, hospitals are straining under the task of storing and managing the deluge of diagnostic films produced every year. A 300-bed hospital generates about 1 gigabyte (8 x 10 9 bits) of picture information every day and is legally bound to hold it for three to seven years--30 years in the case of silicosis or black lung disease, illnesses that may have relevance to future lawsuits. Consequently, hospital warehouses are filling with x-ray film and written reports that are important for analysis of patient histories, for comparison between patients, and for analyzing the progress of disease. Yet only a fraction of the information's potential is being used because access is so complicated. What is more, films are easily lost, erasing valuable medical histories

  14. Chronicle of pediatric radiology

    International Nuclear Information System (INIS)

    Benz-Bohm, Gabriele; Richter, Ernst

    2012-01-01

    The chronicle of pediatric radiology covers the following issues: Development of pediatric radiology in Germany (BRD, DDR, pediatric radiological accommodations); development of pediatric radiology in the Netherlands (chronology and pediatric radiological accommodations); development of pediatric radiology in Austria (chronology and pediatric radiological accommodations); development of pediatric radiology in Switzerland (chronology and pediatric radiological accommodations).

  15. Parameterization of cosmological scale factor during inflationary times

    International Nuclear Information System (INIS)

    Wahba, R.R.

    1989-01-01

    The inflationary period is modeled by generating a cosmological function, lambda(t), that depends on a period of exponential growth followed by a period of exponential decay. The model is equivalent to a single thermodynamic phase change and exhibits all the required features of an inflationary period such as exponential growth of the scale factor plus a natural relaxation (graceful exit) of lambda to the present day cosmological constant. After constraining the model to conditions imposed, by the inflationary hypothesis, a numerical computation is performed over the time period from the Planck time to the beginning of the radiation era. As a result of the constraints on the model, the presence of a very large negative Planckian cosmological constant was found. It was also found that the present-day value of this function, albeit small, is nevertheless positive. Using this model, the growth of the cosmological scale factor R(lambda) was found as a parameterized function of the cosmological function. It is shown that the numerical integration is greatly simplified if the multivalued function is solved. Not only does this greatly simplify the calculation, it shows that the parameterization of the scale factor in terms of the cosmological function is useful. Results are presented in a series of graphs. How the model could be related to either a Grand Unified theory or a quantum mechanical model of inflation in terms of the rate of production and decay of a (massive) X particle created by the initial instability of the vacuum at the planck time is discussed. It is further suggested that the cosmological function provides direct information about the decay rate (and hence the mass) of this X particle

  16. Least-rattling feedback from strong time-scale separation

    Science.gov (United States)

    Chvykov, Pavel; England, Jeremy

    2018-03-01

    In most interacting many-body systems associated with some "emergent phenomena," we can identify subgroups of degrees of freedom that relax on dramatically different time scales. Time-scale separation of this kind is particularly helpful in nonequilibrium systems where only the fast variables are subjected to external driving; in such a case, it may be shown through elimination of fast variables that the slow coordinates effectively experience a thermal bath of spatially varying temperature. In this paper, we investigate how such a temperature landscape arises according to how the slow variables affect the character of the driven quasisteady state reached by the fast variables. Brownian motion in the presence of spatial temperature gradients is known to lead to the accumulation of probability density in low-temperature regions. Here, we focus on the implications of attraction to low effective temperature for the long-term evolution of slow variables. After quantitatively deriving the temperature landscape for a general class of overdamped systems using a path-integral technique, we then illustrate in a simple dynamical system how the attraction to low effective temperature has a fine-tuning effect on the slow variable, selecting configurations that bring about exceptionally low force fluctuation in the fast-variable steady state. We furthermore demonstrate that a particularly strong effect of this kind can take place when the slow variable is tuned to bring about orderly, integrable motion in the fast dynamics that avoids thermalizing energy absorbed from the drive. We thus point to a potentially general feedback mechanism in multi-time-scale active systems, that leads to the exploration of slow variable space, as if in search of fine tuning for a "least-rattling" response in the fast coordinates.

  17. Inverse modelling for real-time estimation of radiological consequences in the early stage of an accidental radioactivity release.

    Science.gov (United States)

    Pecha, Petr; Šmídl, Václav

    2016-11-01

    A stepwise sequential assimilation algorithm is proposed based on an optimisation approach for recursive parameter estimation and tracking of radioactive plume propagation in the early stage of a radiation accident. Predictions of the radiological situation in each time step of the plume propagation are driven by an existing short-term meteorological forecast and the assimilation procedure manipulates the model parameters to match the observations incoming concurrently from the terrain. Mathematically, the task is a typical ill-posed inverse problem of estimating the parameters of the release. The proposed method is designated as a stepwise re-estimation of the source term release dynamics and an improvement of several input model parameters. It results in a more precise determination of the adversely affected areas in the terrain. The nonlinear least-squares regression methodology is applied for estimation of the unknowns. The fast and adequately accurate segmented Gaussian plume model (SGPM) is used in the first stage of direct (forward) modelling. The subsequent inverse procedure infers (re-estimates) the values of important model parameters from the actual observations. Accuracy and sensitivity of the proposed method for real-time forecasting of the accident propagation is studied. First, a twin experiment generating noiseless simulated "artificial" observations is studied to verify the minimisation algorithm. Second, the impact of the measurement noise on the re-estimated source release rate is examined. In addition, the presented method can be used as a proposal for more advanced statistical techniques using, e.g., importance sampling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Cross-Scale Modelling of Subduction from Minute to Million of Years Time Scale

    Science.gov (United States)

    Sobolev, S. V.; Muldashev, I. A.

    2015-12-01

    Subduction is an essentially multi-scale process with time-scales spanning from geological to earthquake scale with the seismic cycle in-between. Modelling of such process constitutes one of the largest challenges in geodynamic modelling today.Here we present a cross-scale thermomechanical model capable of simulating the entire subduction process from rupture (1 min) to geological time (millions of years) that employs elasticity, mineral-physics-constrained non-linear transient viscous rheology and rate-and-state friction plasticity. The model generates spontaneous earthquake sequences. The adaptive time-step algorithm recognizes moment of instability and drops the integration time step to its minimum value of 40 sec during the earthquake. The time step is then gradually increased to its maximal value of 5 yr, following decreasing displacement rates during the postseismic relaxation. Efficient implementation of numerical techniques allows long-term simulations with total time of millions of years. This technique allows to follow in details deformation process during the entire seismic cycle and multiple seismic cycles. We observe various deformation patterns during modelled seismic cycle that are consistent with surface GPS observations and demonstrate that, contrary to the conventional ideas, the postseismic deformation may be controlled by viscoelastic relaxation in the mantle wedge, starting within only a few hours after the great (M>9) earthquakes. Interestingly, in our model an average slip velocity at the fault closely follows hyperbolic decay law. In natural observations, such deformation is interpreted as an afterslip, while in our model it is caused by the viscoelastic relaxation of mantle wedge with viscosity strongly varying with time. We demonstrate that our results are consistent with the postseismic surface displacement after the Great Tohoku Earthquake for the day-to-year time range. We will also present results of the modeling of deformation of the

  19. Integrated biodosimetry in large scale radiological events. Opportunities for civil military co-operation; Integrierte Biodosimetrie bei radiologischen Grossschadensereignissen. Moeglichkeiten fuer zivil-militaerische Zusammenarbeit

    Energy Technology Data Exchange (ETDEWEB)

    Port, M.; Eder, S.F.; Lamkowski, A.; Majewski, M.; Abend, M. [Institut fuer Radiobiologie der Bundeswehr, Muenchen (Germany)

    2016-07-01

    Radiological events like large scale radiological or nuclear accidents, terroristic attacks with radionuclide dispersal devices require rapid and precise medical classification (''triage'') and medical management of a large number of patients. Estimates on the absorbed dose and in particular predictions of the radiation induced health effects are mandatory for optimized allocation of limited medical resources and initiation of patient centred treatment. Among the German Armed Forces Medical Services the Bundeswehr Institute of Radiobiology offers a wide range of tools for the purpose of medical management to cope with different scenarios. The forward deployable mobile Medical Task Force has access to state of the art methodologies summarized into approaches such as physical dosimetry (including mobile gammaspectroscopy), clinical ''dosimetry'' (prodromi, H-Modul) and different means of biological dosimetry (e.g. dicentrics, high throughput gene expression techniques, gamma-H2AX). The integration of these different approaches enables trained physicians of the Medical Task Force to assess individual health injuries as well as prognostic evaluation, considering modern treatment options. To enhance the capacity of single institutions, networking has been recognized as an important emergency response strategy. The capabilities of physical, biological and clinical ''dosimetry'' approaches spanning from low up to high radiation exposures will be discussed. Furthermore civil military opportunities for combined efforts will be demonstrated.

  20. Dental radiology

    International Nuclear Information System (INIS)

    Bhaskar, S.N.

    1982-01-01

    The book presents the radiological manifestations of the maxillodental region in a suitable manner for fast detection and correct diagnosing of diseases of the teeth, soft tissue, and jaws. Classification therefore is made according to the radiological manifestations of the diseases and not according to etiology. (orig./MG) [de

  1. [Reduction of radiological exposure time during radiofrequency catheter ablation procedures using a novel intracardiac localization system based on the Ohm's law].

    Science.gov (United States)

    Catanzariti, Domenico; Maines, Massimiliano; De Girolamo, Piergiuseppe; Cozzi, Fulvio; Cemin, Claudio; Vergara, Giuseppe

    2004-08-01

    Three-dimensional nonfluoroscopic system may be helpful to guide radiofrequency catheter ablation procedures and to reduce the radiological exposure. A new intracardiac navigation and multicatheter visualization system based on Ohm's law (LocaLisa, Medtronic, Minneapolis, MN, USA) has been recently introduced. The aim of our study was to assess the efficacy of the Loca-Lisa system in comparison to fluoroscopy-based approach in reducing the radiological exposure time required for radiofrequency catheter ablation procedures. One hundred and thirty-seven consecutive patients underwent LocaLisa-based radiofrequency catheter ablation procedures in our cardiac electrophysiology laboratory during 19 months of LocaLisa utilization (from October 2001 to April 2003): 46 atrial flutter, 44 atrioventricular node reentrant tachycardia, 16 atrioventricular reentry tachycardia due to atrioventricular accessory pathway, 14 atrial fibrillation, 11 ectopic atrial tachycardia, and 6 atrioventricular node modulation. We retrospectively compared the radiological exposure times of this group of patients to those of the last 137 patients undergone fluoroscopy-based radiofrequency catheter ablation procedures for curing the same index arrhythmia by the same procedural protocol. The mean radiological exposure time was significantly shorter for the LocaLisa-based radiofrequency catheter ablation procedures (16 +/- 12 vs 34 +/- 17 min; reduction of 53%, p < 0.01) and it occurred for all the arrhythmia types. The reduction was of 64% (from 39 +/- 18 to 14 +/- 12 min, p < 0.01) for atrial flutter, 42% (from 24 +/- 10 to 14 +/- 11 min, p < 0.01) for atrioventricular nodal reentrant tachycardia, 30% (from 40 +/- 14 to 28 +/- 14 min, p = 0.02) for atrioventricular reentry tachycardia, 57% (from 49 +/- 12 to 21 +/- 13 min, p < 0.01) for atrial fibrillation (right atrial linear lesions), 50% (from 38 +/- 12 to 19 +/- 8 min, p < 0.01) for ectopic atrial tachycardia and 42% (from 12 +/- 11 to 7 +/- 5

  2. Laenderyggens degeneration og radiologi

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Gosvig, Kasper Kjaerulf; Sonne-Holm, Stig

    2006-01-01

    and significant relationships between radiological findings and subjective symptoms have both been notoriously difficult to identify. The lack of consensus on clinical criteria and radiological definitions has hampered the undertaking of properly executed epidemiological studies. The natural history of LBP......Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP...

  3. Laenderyggens degeneration og radiologi

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Gosvig, Kasper Kjaerulf; Sonne-Holm, Stig

    2006-01-01

    Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP and signi......Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP...... and significant relationships between radiological findings and subjective symptoms have both been notoriously difficult to identify. The lack of consensus on clinical criteria and radiological definitions has hampered the undertaking of properly executed epidemiological studies. The natural history of LBP...

  4. Prewhitening of hydroclimatic time series? Implications for inferred change and variability across time scales

    Science.gov (United States)

    Razavi, Saman; Vogel, Richard

    2018-02-01

    Prewhitening, the process of eliminating or reducing short-term stochastic persistence to enable detection of deterministic change, has been extensively applied to time series analysis of a range of geophysical variables. Despite the controversy around its utility, methodologies for prewhitening time series continue to be a critical feature of a variety of analyses including: trend detection of hydroclimatic variables and reconstruction of climate and/or hydrology through proxy records such as tree rings. With a focus on the latter, this paper presents a generalized approach to exploring the impact of a wide range of stochastic structures of short- and long-term persistence on the variability of hydroclimatic time series. Through this approach, we examine the impact of prewhitening on the inferred variability of time series across time scales. We document how a focus on prewhitened, residual time series can be misleading, as it can drastically distort (or remove) the structure of variability across time scales. Through examples with actual data, we show how such loss of information in prewhitened time series of tree rings (so-called "residual chronologies") can lead to the underestimation of extreme conditions in climate and hydrology, particularly droughts, reconstructed for centuries preceding the historical period.

  5. Dynamic Leidenfrost Effect: Relevant Time and Length Scales

    Science.gov (United States)

    Shirota, Minori; van Limbeek, Michiel A. J.; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

    2016-02-01

    When a liquid droplet impacts a hot solid surface, enough vapor may be generated under it to prevent its contact with the solid. The minimum solid temperature for this so-called Leidenfrost effect to occur is termed the Leidenfrost temperature, or the dynamic Leidenfrost temperature when the droplet velocity is non-negligible. We observe the wetting or drying and the levitation dynamics of the droplet impacting on an (isothermal) smooth sapphire surface using high-speed total internal reflection imaging, which enables us to observe the droplet base up to about 100 nm above the substrate surface. By this method we are able to reveal the processes responsible for the transitional regime between the fully wetting and the fully levitated droplet as the solid temperature increases, thus shedding light on the characteristic time and length scales setting the dynamic Leidenfrost temperature for droplet impact on an isothermal substrate.

  6. BOX-COX REGRESSION METHOD IN TIME SCALING

    Directory of Open Access Journals (Sweden)

    ATİLLA GÖKTAŞ

    2013-06-01

    Full Text Available Box-Cox regression method with λj, for j = 1, 2, ..., k, power transformation can be used when dependent variable and error term of the linear regression model do not satisfy the continuity and normality assumptions. The situation obtaining the smallest mean square error  when optimum power λj, transformation for j = 1, 2, ..., k, of Y has been discussed. Box-Cox regression method is especially appropriate to adjust existence skewness or heteroscedasticity of error terms for a nonlinear functional relationship between dependent and explanatory variables. In this study, the advantage and disadvantage use of Box-Cox regression method have been discussed in differentiation and differantial analysis of time scale concept.

  7. Flexoelectricity and competition of time scales in electroconvection.

    Science.gov (United States)

    Tóth-Katona, Tibor; Eber, Nándor; Buka, Agnes; Krekhov, Alexei

    2008-09-01

    An unexpected type of behavior in electroconvection (EC) has been detected in nematic liquid crystals (NLCs) under the condition of comparable time scales of the director relaxation and the period of the driving ac voltage. The studied NLCs exhibit standard EC (s-EC) at the onset of the instability, except one compound in which nonstandard EC (ns-EC) has been detected. In the relevant frequency region, the threshold voltage for conductive s-EC bends down considerably, while for dielectric s-EC it bends up strongly with the decrease of the driving frequency. We show that inclusion of the flexoelectric effect into the theoretical description of conductive s-EC leads to quantitative agreement, while for dielectric s-EC a qualitative agreement is achieved. The frequency dependence of the threshold voltage for ns-EC strongly resembles that of the dielectric s-EC.

  8. The effect of photosynthesis time scales on microalgae productivity.

    Science.gov (United States)

    Hartmann, Philipp; Béchet, Quentin; Bernard, Olivier

    2014-01-01

    Microalgae are often seen as a potential biofuel producer. In order to predict achievable productivities in the so called raceway culturing system, the dynamics of photosynthesis has to be taken into account. In particular, the dynamical effect of inhibition by an excess of light (photoinhibition) must be represented. We propose a model considering both photosynthesis and growth dynamics. This model involves three different time scales. We study the response of this model to fluctuating light with different frequencies by slow/fast approximations. Therefore, we identify three different regimes for which a simplified expression for the model can be derived. These expressions give a hint on productivity improvement which can be expected by stimulating photosynthesis with a faster hydrodynamics.

  9. Towards a stable numerical time scale for the early Paleogene

    Science.gov (United States)

    Hilgen, Frederik; Kuiper, Klaudia; Sierro, Francisco J.; Wotzlaw, Jorn; Schaltegger, Urs; Sahy, Diana; Condon, Daniel

    2014-05-01

    The construction of an astronomical time scale for the early Paleogene is hampered by ambiguities in the number, correlation and tuning of 405-kyr eccentricity related cycles in deep marine records from ODP cores and land-based sections. The two most competing age models result in astronomical ages for the K/Pg boundary that differ by ~750 kyr (~66.0 Ma of Vandenberghe et al. (2012) versus 65.25 Ma of Westerhold et al. (2012); these ages in turn are consistent with proposed ages for the Fish Canyon sanidine (FCs) that differ by ~300 kyr (28.201 Ma of Kuiper et al. (2008) versus 27.89 Ma of Westerhold et al. (2012)); an even older age of 28.294 Ma is proposed based on a statistical optimization model (Renne et al., 2011). The astronomically calibrated FCs age of 28.201 ± 0.046 Ma of Kuiper et al. (2008), which is consistent with the astronomical age of ~66.0 Ma for the K/Pg boundary, is currently adopted in the standard geological time scale (GTS2012). Here we combine new and published data in an attempt to solve the controversy and arrive at a stable nuemrical time scale for the early Paleogene. Supporting their younger age model, Westerhold et al. (2012) argue that the tuning of Miocene sections in the Mediterranean, which underlie the older FCs age of Kuiper et al. (2008) and, hence, the coupled older early Paleogene age model of Vandenberghe et al. (2012), might be too old by three precession cycles. We thoroughly rechecked this tuning; distinctive cycle patterns related to eccentricity and precession-obliquity interference make a younger tuning that would be consistent with the younger astronomical age of 27.89 Ma for the FCs of Westerhold et al. (2012) challenging. Next we compared youngest U/Pb zircon and astronomical ages for a number of ash beds in the tuned Miocene section of Monte dei Corvi. These ages are indistinguishable, indicating that the two independent dating methods yield the same age when the same event is dated. This is consistent with results

  10. Radiological colpocephaly

    International Nuclear Information System (INIS)

    Landman, J.; Dulitzki, F.; Sirota, L.; Aloni, D.; Bar-Ziv, J.; Weitz, R.; Shuper, A.; Gadoth, N.

    1989-01-01

    The term colpocephaly, meaning disproportional enlargement of the occipital horns of the lateral ventricles, was considered in the past to be a distinct congenital malformation acquired in early intrauterine life. During the last few years several causes were reported in whom a variety of intrauterine and perinatal causes could be associated with this radiological picture. We report on 9 children with radiological colpocephaly in whom intrauterine and/or perinatal injury to the developing brain seemed to be the cause of colpocephaly. It is evident from our observations that 'radiological colpocephaly' is a non-specific finding caused frequently by CNS damage acquired during intrauterine and perinatal life. (author)

  11. Real-time fluoroscopic needle guidance in the interventional radiology suite using navigational software for percutaneous bone biopsies in children

    Energy Technology Data Exchange (ETDEWEB)

    Shellikeri, Sphoorti; Srinivasan, Abhay; Krishnamurthy, Ganesh; Vatsky, Seth; Zhu, Xiaowei; Keller, Marc S.; Cahill, Anne Marie [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Setser, Randolph M. [Siemens Medical Solutions USA, Inc., Hoffman Estates, IL (United States); Hwang, Tiffany J. [University of Southern California, Keck School of Medicine, Los Angeles, CA (United States); Girard, Erin [Siemens Medical Solutions USA, Inc., Princeton, NJ (United States)

    2017-07-15

    Navigational software provides real-time fluoroscopic needle guidance for percutaneous procedures in the Interventional Radiology (IR) suite. We describe our experience with navigational software for pediatric percutaneous bone biopsies in the IR suite and compare technical success, diagnostic accuracy, radiation dose and procedure time with that of CT-guided biopsies. Pediatric bone biopsies performed using navigational software (Syngo iGuide, Siemens Healthcare) from 2011 to 2016 were prospectively included and anatomically matched CT-guided bone biopsies from 2008 to 2016 were retrospectively reviewed with institutional review board approval. C-arm CT protocols used for navigational software-assisted cases included institution-developed low-dose (0.1/0.17 μGy/projection), regular-dose (0.36 μGy/projection), or a combination of low-dose/regular-dose protocols. Estimated effective radiation dose and procedure times were compared between software-assisted and CT-guided biopsies. Twenty-six patients (15 male; mean age: 10 years) underwent software-assisted biopsies (15 pelvic, 7 lumbar and 4 lower extremity) and 33 patients (13 male; mean age: 9 years) underwent CT-guided biopsies (22 pelvic, 7 lumbar and 4 lower extremity). Both modality biopsies resulted in a 100% technical success rate. Twenty-five of 26 (96%) software-assisted and 29/33 (88%) CT-guided biopsies were diagnostic. Overall, the effective radiation dose was significantly lower in software-assisted than CT-guided cases (3.0±3.4 vs. 6.6±7.7 mSv, P=0.02). The effective dose difference was most dramatic in software-assisted cases using low-dose C-arm CT (1.2±1.8 vs. 6.6±7.7 mSv, P=0.001) or combined low-dose/regular-dose C-arm CT (1.9±2.4 vs. 6.6±7.7 mSv, P=0.04), whereas effective dose was comparable in software-assisted cases using regular-dose C-arm CT (6.0±3.5 vs. 6.6±7.7 mSv, P=0.7). Mean procedure time was significantly lower for software-assisted cases (91±54 vs. 141±68 min, P=0

  12. Continent-scale global change attribution in European birds - combining annual and decadal time scales

    DEFF Research Database (Denmark)

    Jørgensen, Peter Søgaard; Böhning-Gaese, Katrin; Thorup, Kasper

    2016-01-01

    foundation for attributing species responses to global change may be achieved by complementing an attributes-based approach by one estimating the relationship between repeated measures of organismal and environmental changes over short time scales. To assess the benefit of this multiscale perspective, we......Species attributes are commonly used to infer impacts of environmental change on multiyear species trends, e.g. decadal changes in population size. However, by themselves attributes are of limited value in global change attribution since they do not measure the changing environment. A broader...... investigate the recent impact of multiple environmental changes on European farmland birds, here focusing on climate change and land use change. We analyze more than 800 time series from 18 countries spanning the past two decades. Analysis of long-term population growth rates documents simultaneous responses...

  13. The pace of aging: Intrinsic time scales in demography

    Directory of Open Access Journals (Sweden)

    Tomasz Wrycza

    2014-05-01

    Full Text Available Background: The pace of aging is a concept that captures the time-related aspect of aging. It formalizesthe idea of a characteristic life span or intrinsic population time scale. In the rapidly developing field of comparative biodemography, measures that account for inter-speciesdifferences in life span are needed to compare how species age. Objective: We aim to provide a mathematical foundation for the concept of pace. We derive desiredmathematical properties of pace measures and suggest candidates which satisfy these properties. Subsequently, we introduce the concept of pace-standardization, which reveals differences in demographic quantities that are not due to pace. Examples and consequences are discussed. Conclusions: Mean life span (i.e., life expectancy from birth or from maturity is intuitively appealing,theoretically justified, and the most appropriate measure of pace. Pace-standardizationprovides a serviceable method for comparative aging studies to explore differences indemographic patterns of aging across species, and it may considerably alter conclusionsabout the strength of aging.

  14. Radiological assessment and optimization

    International Nuclear Information System (INIS)

    Zeevaert, T.; Sohier, A.

    1998-01-01

    The objectives of SCK-CEN's research in the field of radiological assessment and optimization are (1) to implement ALARA principles in activities with radiological consequences; (2) to develop methodologies for radiological optimization in decision-aiding; (3) to improve methods to assess in real time the radiological hazards in the environment in case of an accident; (4) to develop methods and programmes to assist decision-makers during a nuclear emergency; (5) to support the policy of radioactive waste management authorities in the field of radiation protection; (6) to investigate computer codes in the area of multi criteria analysis; (7) to organise courses on off-site emergency response to nuclear accidents. Main achievements in these areas for 1997 are summarised

  15. Ergonomics in radiology

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, N. [Department of Radiology, University Hospital of Wales, Cardiff (United Kingdom)], E-mail: nimitgoyal@doctors.org.uk; Jain, N.; Rachapalli, V. [Department of Radiology, University Hospital of Wales, Cardiff (United Kingdom)

    2009-02-15

    The use of computers is increasing in every field of medicine, especially radiology. Filmless radiology departments, speech recognition software, electronic request forms and teleradiology are some of the recent developments that have substantially increased the amount of time a radiologist spends in front of a computer monitor. Computers are also needed for searching literature on the internet, communicating via e-mails, and preparing for lectures and presentations. It is well known that regular computer users can suffer musculoskeletal injuries due to repetitive stress. The role of ergonomics in radiology is to ensure that working conditions are optimized in order to avoid injury and fatigue. Adequate workplace ergonomics can go a long way in increasing productivity, efficiency, and job satisfaction. We review the current literature pertaining to the role of ergonomics in modern-day radiology especially with the development of picture archiving and communication systems (PACS) workstations.

  16. Radiological assessment and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaert, T.; Sohier, A

    1998-07-01

    The objectives of SCK-CEN's research in the field of radiological assessment and optimization are (1) to implement ALARA principles in activities with radiological consequences; (2) to develop methodologies for radiological optimization in decision-aiding; (3) to improve methods to assess in real time the radiological hazards in the environment in case of an accident; (4) to develop methods and programmes to assist decision-makers during a nuclear emergency; (5) to support the policy of radioactive waste management authorities in the field of radiation protection; (6) to investigate computer codes in the area of multi criteria analysis; (7) to organise courses on off-site emergency response to nuclear accidents. Main achievements in these areas for 1997 are summarised.

  17. Ergonomics in radiology

    International Nuclear Information System (INIS)

    Goyal, N.; Jain, N.; Rachapalli, V.

    2009-01-01

    The use of computers is increasing in every field of medicine, especially radiology. Filmless radiology departments, speech recognition software, electronic request forms and teleradiology are some of the recent developments that have substantially increased the amount of time a radiologist spends in front of a computer monitor. Computers are also needed for searching literature on the internet, communicating via e-mails, and preparing for lectures and presentations. It is well known that regular computer users can suffer musculoskeletal injuries due to repetitive stress. The role of ergonomics in radiology is to ensure that working conditions are optimized in order to avoid injury and fatigue. Adequate workplace ergonomics can go a long way in increasing productivity, efficiency, and job satisfaction. We review the current literature pertaining to the role of ergonomics in modern-day radiology especially with the development of picture archiving and communication systems (PACS) workstations

  18. Ozone time scale decomposition and trend assessment from surface observations

    Science.gov (United States)

    Boleti, Eirini; Hueglin, Christoph; Takahama, Satoshi

    2017-04-01

    Emissions of ozone precursors have been regulated in Europe since around 1990 with control measures primarily targeting to industries and traffic. In order to understand how these measures have affected air quality, it is now important to investigate concentrations of tropospheric ozone in different types of environments, based on their NOx burden, and in different geographic regions. In this study, we analyze high quality data sets for Switzerland (NABEL network) and whole Europe (AirBase) for the last 25 years to calculate long-term trends of ozone concentrations. A sophisticated time scale decomposition method, called the Ensemble Empirical Mode Decomposition (EEMD) (Huang,1998;Wu,2009), is used for decomposition of the different time scales of the variation of ozone, namely the long-term trend, seasonal and short-term variability. This allows subtraction of the seasonal pattern of ozone from the observations and estimation of long-term changes of ozone concentrations with lower uncertainty ranges compared to typical methodologies used. We observe that, despite the implementation of regulations, for most of the measurement sites ozone daily mean values have been increasing until around mid-2000s. Afterwards, we observe a decline or a leveling off in the concentrations; certainly a late effect of limitations in ozone precursor emissions. On the other hand, the peak ozone concentrations have been decreasing for almost all regions. The evolution in the trend exhibits some differences between the different types of measurement. In addition, ozone is known to be strongly affected by meteorology. In the applied approach, some of the meteorological effects are already captured by the seasonal signal and already removed in the de-seasonalized ozone time series. For adjustment of the influence of meteorology on the higher frequency ozone variation, a statistical approach based on Generalized Additive Models (GAM) (Hastie,1990;Wood,2006), which corrects for meteorological

  19. Review of Tropical-Extratropical Teleconnections on Intraseasonal Time Scales

    Science.gov (United States)

    Stan, Cristiana; Straus, David M.; Frederiksen, Jorgen S.; Lin, Hai; Maloney, Eric D.; Schumacher, Courtney

    2017-12-01

    The interactions and teleconnections between the tropical and midlatitude regions on intraseasonal time scales are an important modulator of tropical and extratropical circulation anomalies and their associated weather patterns. These interactions arise due to the impact of the tropics on the extratropics, the impact of the midlatitudes on the tropics, and two-way interactions between the regions. Observational evidence, as well as theoretical studies with models of complexity ranging from the linear barotropic framework to intricate Earth system models, suggest the involvement of a myriad of processes and mechanisms in generating and maintaining these interconnections. At this stage, our understanding of these teleconnections is primarily a collection of concepts; a comprehensive theoretical framework has yet to be established. These intraseasonal teleconnections are increasingly recognized as an untapped source of potential subseasonal predictability. However, the complexity and diversity of mechanisms associated with these teleconnections, along with the lack of a conceptual framework to relate them, prevent this potential predictability from being translated into realized forecast skill. This review synthesizes our progress in understanding the observed characteristics of intraseasonal tropical-extratropical interactions and their associated mechanisms, identifies the significant gaps in this understanding, and recommends new research endeavors to address the remaining challenges.

  20. Digital imaging in diagnostic radiology

    International Nuclear Information System (INIS)

    Newell, J.D. Jr.; Kelsey, C.A.

    1990-01-01

    This monograph on digital imaging provides a basic overview of this field at the present time. This paper covers clinical application, including subtraction angiography; chest radiology; genitourinary, gastrointestinal, and breast radiology; and teleradiology. The chest section also includes an explanation of multiple beam equalization radiography. The remaining chapters discuss some of the technical aspects of digital radiology. It includes the basic technology of digital radiography, image compression, and reconstruction information on the economics of digital radiography

  1. EON: software for long time simulations of atomic scale systems

    Science.gov (United States)

    Chill, Samuel T.; Welborn, Matthew; Terrell, Rye; Zhang, Liang; Berthet, Jean-Claude; Pedersen, Andreas; Jónsson, Hannes; Henkelman, Graeme

    2014-07-01

    The EON software is designed for simulations of the state-to-state evolution of atomic scale systems over timescales greatly exceeding that of direct classical dynamics. States are defined as collections of atomic configurations from which a minimization of the potential energy gives the same inherent structure. The time evolution is assumed to be governed by rare events, where transitions between states are uncorrelated and infrequent compared with the timescale of atomic vibrations. Several methods for calculating the state-to-state evolution have been implemented in EON, including parallel replica dynamics, hyperdynamics and adaptive kinetic Monte Carlo. Global optimization methods, including simulated annealing, basin hopping and minima hopping are also implemented. The software has a client/server architecture where the computationally intensive evaluations of the interatomic interactions are calculated on the client-side and the state-to-state evolution is managed by the server. The client supports optimization for different computer architectures to maximize computational efficiency. The server is written in Python so that developers have access to the high-level functionality without delving into the computationally intensive components. Communication between the server and clients is abstracted so that calculations can be deployed on a single machine, clusters using a queuing system, large parallel computers using a message passing interface, or within a distributed computing environment. A generic interface to the evaluation of the interatomic interactions is defined so that empirical potentials, such as in LAMMPS, and density functional theory as implemented in VASP and GPAW can be used interchangeably. Examples are given to demonstrate the range of systems that can be modeled, including surface diffusion and island ripening of adsorbed atoms on metal surfaces, molecular diffusion on the surface of ice and global structural optimization of nanoparticles.

  2. Nonequilibrium Physics at Short Time Scales: Formation of Correlations

    International Nuclear Information System (INIS)

    Peliti, L

    2005-01-01

    It is a happy situation when similar concepts and theoretical techniques can be applied to widely different physical systems because of a deep similarity in the situations being studied. The book illustrates this well; it focuses on the description of correlations in quantum systems out of equilibrium at very short time scales, prompted by experiments with short laser pulses in semiconductors, and in complex reactions in heavy nuclei. In both cases the experiments are characterized by nonlinear dynamics and by strong correlations out of equilibrium. In some systems there are also important finite-size effects. The book comprises several independent contributions of moderate length, and I sometimes felt that a more intensive effort in cross-coordination of the different contributions could have been of help. It is divided almost equally between theory and experiment. In the theoretical part, there is a thorough discussion both of the kinematic aspects (description of correlations) and the dynamical ones (evaluation of correlations). The experimental part is naturally divided according to the nature of the system: the interaction of pulsed lasers with matter on the one hand, and the correlations in finite-size systems (nanoparticles and nuclei) on the other. There is also a discussion on the dynamics of superconductors, a subject currently of great interest. Although an effort has been made to keep each contribution self-contained, I must admit that reading level is uneven. However, there are a number of thorough and stimulating contributions that make this book a useful introduction to the topic at the level of graduate students or researchers acquainted with quantum statistical mechanics. (book review)

  3. Radiological engineering evaluation of the delay time line air scrubber located at the Clinton P. Anderson Meson Physics Facility (LAMPF)

    International Nuclear Information System (INIS)

    Huneycutt, S.E.

    1996-05-01

    The purpose of this study was to determine the effects of the addition of an air scrubber to an already existing delay line and whether it would scrub 11 CO 2 . There were three main objectives of this study. The first objective was to determine the scrubbing efficiency of the scrubber. The scrubbing efficiency was then used to predict the dose rates in the scrubber area and compare those values with measurements from radiological surveys. The third objective was to determine if the shield blocks were effective in reducing the dose rates in the scrubber area. The activities were measured before and during scrubber operation and this information was used to calculate the scrubbing efficiency and the efficiency of 11 CO 2 removal was determined to be around 50%. Microshield was then used to predict dose rates and compared those values with measurements from radiological surveys. This was also used to determine the that the shield blocks around the scrubber were effective in reducing the dose rates from the radiation field produced by the radionuclides in the scrubber

  4. Attractors of relaxation discrete-time systems with chaotic dynamics on a fast time scale

    International Nuclear Information System (INIS)

    Maslennikov, Oleg V.; Nekorkin, Vladimir I.

    2016-01-01

    In this work, a new type of relaxation systems is considered. Their prominent feature is that they comprise two distinct epochs, one is slow regular motion and another is fast chaotic motion. Unlike traditionally studied slow-fast systems that have smooth manifolds of slow motions in the phase space and fast trajectories between them, in this new type one observes, apart the same geometric objects, areas of transient chaos. Alternating periods of slow regular motions and fast chaotic ones as well as transitions between them result in a specific chaotic attractor with chaos on a fast time scale. We formulate basic properties of such attractors in the framework of discrete-time systems and consider several examples. Finally, we provide an important application of such systems, the neuronal electrical activity in the form of chaotic spike-burst oscillations.

  5. Some Differential Inequalities on Time Scales and Their Applications to Feedback Control Systems

    Directory of Open Access Journals (Sweden)

    Yonghong Fan

    2017-01-01

    Full Text Available This paper deals with feedback control systems on time scales. Firstly, we generalize the semicycle concept to time scales and then establish some differential inequalities on time scales. Secondly, as applications of these inequalities, we study the uniform ultimate boundedness of solutions of these systems. We give a new method to investigate the permanence of ecosystem on time scales. And some known results have been generalized. Finally, an example is given to support the result.

  6. Entangled time in flocking: Multi-time-scale interaction reveals emergence of inherent noise.

    Science.gov (United States)

    Niizato, Takayuki; Murakami, Hisashi

    2018-01-01

    Collective behaviors that seem highly ordered and result in collective alignment, such as schooling by fish and flocking by birds, arise from seamless shuffling (such as super-diffusion) and bustling inside groups (such as Lévy walks). However, such noisy behavior inside groups appears to preclude the collective behavior: intuitively, we expect that noisy behavior would lead to the group being destabilized and broken into small sub groups, and high alignment seems to preclude shuffling of neighbors. Although statistical modeling approaches with extrinsic noise, such as the maximum entropy approach, have provided some reasonable descriptions, they ignore the cognitive perspective of the individuals. In this paper, we try to explain how the group tendency, that is, high alignment, and highly noisy individual behavior can coexist in a single framework. The key aspect of our approach is multi-time-scale interaction emerging from the existence of an interaction radius that reflects short-term and long-term predictions. This multi-time-scale interaction is a natural extension of the attraction and alignment concept in many flocking models. When we apply this method in a two-dimensional model, various flocking behaviors, such as swarming, milling, and schooling, emerge. The approach also explains the appearance of super-diffusion, the Lévy walk in groups, and local equilibria. At the end of this paper, we discuss future developments, including extending our model to three dimensions.

  7. Radiological protection in interventional radiology

    International Nuclear Information System (INIS)

    Padovani, R.

    2001-01-01

    Interventional radiology (IR) reduces the need for many traditional interventions, particularly surgery, so reducing the discomfort and risk for patients compared with traditional systems. IR procedures are frequently performed by non-radiologist physicians, often without the proper radiological equipment and sufficient knowledge of radiation protection. Levels of doses to patients and staff in IR vary enormously. A poor correlation exists between patient and staff dose, and large variations of dose are reported for the same procedure. The occurrence of deterministic effects in patients is another peculiar aspect of IR owing to the potentially high skin doses of some procedures. The paper reviews the use of IR and the radiological protection of patients and staff, and examines the need for new standards for IR equipment and the training of personnel. (author)

  8. Whither Radiology?

    African Journals Online (AJOL)

    15 Mei 1974 ... cess of those audible to animals. Sonar should not be confused with X-rays, which have biological effects due to the production of ionising radiation, whereas ultrasound is vibrational or mechanical energy of an ultrahigh frequency. Ultrasound has taken over from conventional radiology in quite a few ...

  9. Radiologic considerations

    International Nuclear Information System (INIS)

    Judge, L.O.

    1987-01-01

    An increasing variety of imaging modalities as well as refinements of interventional techniques have led to a resurgence of radiologic interest and participation in urolithiasis management. Judicious selection of the diagnostic examination, close monitoring during the procedure, consultation with urologic colleagues, and a careful regard for radiation safety guidelines define the role of the radiologist in renal stone disease

  10. Multiple dynamical time-scales in networks with hierarchically ...

    Indian Academy of Sciences (India)

    Recent research, on the other hand, has revealed that networks which are indistinguishable at either of these two scales may nevertheless have radically different behaviour [7]. The origin of this difference lies in their mesoscopic organization which can be structurally manifested as patterns in the arrangement of links.

  11. Length and time scales of atmospheric moisture recycling

    NARCIS (Netherlands)

    Van der Ent, R.J.; Savenije, H.H.G.

    2011-01-01

    It is difficult to quantify the degree to which terrestrial evaporation supports the occurrence of precipitation within a certain study region (i.e. regional moisture recycling) due to the scale- and shape-dependence of regional moisture recycling ratios. In this paper we present a novel approach to

  12. Changes in channel morphology over human time scales [Chapter 32

    Science.gov (United States)

    John M. Buffington

    2012-01-01

    Rivers are exposed to changing environmental conditions over multiple spatial and temporal scales, with the imposed environmental conditions and response potential of the river modulated to varying degrees by human activity and our exploitation of natural resources. Watershed features that control river morphology include topography (valley slope and channel...

  13. Real-time assessment of exposure dose to workers in radiological environments during decommissioning of nuclear facilities

    International Nuclear Information System (INIS)

    Jeong, KwanSeong; Choi, ByungSeon; Moon, JeiKwon; Hyun, Dongjun; Lee, Jonghwan; Kim, IkJune; Kim, GeunHo; Seo, JaeSeok; Jeong, SeongYoung; Lee, JungJun; Song, HaeSang; Lee, SangWha; Son, BongKi

    2014-01-01

    Highlights: • The method of exposure dose assessment to workers during decommissioning of nuclear facilities. • The environments of simulation were designed under a virtual reality. • To assess exposure dose to workers, human model was developed within a virtual reality. - Abstract: This objective of this paper is to develop a method to simulate and assess the exposure dose to workers during decommissioning of nuclear facilities. To simulate several scenarios, decommissioning environments were designed using virtual reality. To assess exposure dose to workers, a human model was also developed using virtual reality. The exposure dose was measured and assessed under the principle of ALARA in accordance with radiological environmental change. This method will make it possible to plan for the exposure dose to workers during decommissioning of nuclear facilities

  14. Decision-making in crisis situation at the Cea Saclay by the real-time cartography of radiological consequences

    International Nuclear Information System (INIS)

    Comte, N.; Bourgeois, L.

    2001-01-01

    The S.P.R of Saclay has developed a computer system based around three modules: term sources calculation, transfers and radiological consequences in the installation based on a compartment model for the first one; dispersion and impact on environment based on a model with Doury type Gaussian fits with dose coefficients coming from the European directive 96/29, from the ICRP 71 and Kocher for the second one; cartography with the help of a geographical information system including road map background, a Saclay center plan with environment monitoring stations and the measurements points P.P.I. ( first intervention plan) on which are superposed the panache diffusion cone and the isodoses curves. (N.C.)

  15. Radiology's value chain.

    Science.gov (United States)

    Enzmann, Dieter R

    2012-04-01

    A diagnostic radiology value chain is constructed to define its main components, all of which are vulnerable to change, because digitization has caused disaggregation of the chain. Some components afford opportunities to improve productivity, some add value, while some face outsourcing to lower labor cost and to information technology substitutes, raising commoditization risks. Digital image information, because it can be competitive at smaller economies of scale, allows faster, differential rates of technological innovation of components, initiating a centralization-to-decentralization technology trend. Digitization, having triggered disaggregation of radiology's professional service model, may soon usher in an information business model. This means moving from a mind-set of "reading images" to an orientation of creating and organizing information for greater accuracy, faster speed, and lower cost in medical decision making. Information businesses view value chain investments differently than do small professional services. In the former model, producing a better business product will extend image interpretation beyond a radiologist's personal fund of knowledge to encompass expanding external imaging databases. A follow-on expansion with integration of image and molecular information into a report will offer new value in medical decision making. Improved interpretation plus new integration will enrich and diversify radiology's key service products, the report and consultation. A more robust, information-rich report derived from a "systems" and "computational" radiology approach will be facilitated by a transition from a professional service to an information business. Under health care reform, radiology will transition its emphasis from volume to greater value. Radiology's future brightens with the adoption of a philosophy of offering information rather than "reads" for decision making. Staunchly defending the status quo via turf wars is unlikely to constitute a

  16. Global terrestrial biogeochemistry: Perturbations, interactions, and time scales

    Energy Technology Data Exchange (ETDEWEB)

    Braswell, B.H. Jr.

    1996-12-01

    Global biogeochemical processes are being perturbed by human activity, principally that which is associated with industrial activity and expansion of urban and agricultural complexes. Perturbations have manifested themselves at least since the beginning of the 19th Century, and include emissions of CO{sub 2} and other pollutants from fossil fuel combustion, agricultural emissions of reactive nitrogen, and direct disruption of ecosystem function through land conversion. These perturbations yield local impacts, but there are also global consequences that are the sum of local-scale influences. Several approaches to understanding the global-scale implications of chemical perturbations to the Earth system are discussed. The lifetime of anthropogenic CO{sub 2} in the atmosphere is an important concept for understanding the current and future commitment to an altered atmospheric heat budget. The importance of the terrestrial biogeochemistry relative to the lifetime of excess CO{sub 2} is demonstrated using dynamic, aggregated models of the global carbon cycle.

  17. Gastrointestinal and hepatobiliary radiology

    International Nuclear Information System (INIS)

    Graham, R.N.J.; Perriss, R.W.; Scarsbrook, A.F.

    2006-01-01

    This is the fifth in the series of short reviews of internet-based radiological learning resources and will focus on gastrointestinal (GI) and hepatobiliary radiology. Below are details of a few of the higher quality resources currently available. Most of the sites cater for medical students and trainee or non-specialist radiologists, but may be also be of interest to specialists, especially for use in teaching. Hyperlinks are available in the electronic version of this article and were all active at the time of going to press (May 2006)

  18. Grasping Deep Time with Scaled Space in Personal Environs

    DEFF Research Database (Denmark)

    Jacobsen, B. H.

    2014-01-01

    Deep time comprises the deep past before written history all the way back to the Big Bang as well as the deep future from the time of our grandchildren and beyond the lifetime of our Sun. Numerous installations called time walks or geology paths have previously been designed to communicate...... of modern man, the age of dinosaurs ended at 650 m and the Big Bang is 137 km away. This choice obviously makes mental calculations easy, and all of time fits inside a geographical area of moderate size and so helps the citizen gain ownership to this learning tool and hence to time. The idea was tested...... years (3.9 km); the full path of time from the Big Bang to the death of the Sun was installed as a downloadable kmz file for Google Earth, linking to 25 video narratives recorded on location along the path....

  19. Dental radiology.

    Science.gov (United States)

    Woodward, Tony M

    2009-02-01

    Dental radiology is the core diagnostic modality of veterinary dentistry. Dental radiographs assist in detecting hidden painful pathology, estimating the severity of dental conditions, assessing treatment options, providing intraoperative guidance, and also serve to monitor success of prior treatments. Unfortunately, most professional veterinary training programs provide little or no training in veterinary dentistry in general or dental radiology in particular. Although a technical learning curve does exist, the techniques required for producing diagnostic films are not difficult to master. Regular use of dental x-rays will increase the amount of pathology detected, leading to healthier patients and happier clients who notice a difference in how their pet feels. This article covers equipment and materials needed to produce diagnostic intraoral dental films. A simplified guide for positioning will be presented, including a positioning "cheat sheet" to be placed next to the dental x-ray machine in the operatory. Additionally, digital dental radiograph systems will be described and trends for their future discussed.

  20. Genitourinary radiology

    Energy Technology Data Exchange (ETDEWEB)

    McClennan, B.L.

    1982-01-01

    A literature review of genitourinary radiology highlights new findings in the field that have occurred in the past year. The physiology of contrast media, and the occasional life-threatening contrast medial reaction are discussed. Common urologic problems such as stones, infection, and obstruction are examined in order to interpret static radiographs in a more meaningful way. The field of interventional uroradiology continues to expand, with new procedures being tried and new indications for old procedures being developed. (KRM)

  1. Chest radiology

    International Nuclear Information System (INIS)

    Reed, J.C.

    1990-01-01

    This book is a reference in plain chest film diagnosis provides a thorough background in the differential diagnosis of 22 of the most common radiologic patterns of chest disease. Each chapter is introduced with problem cases and a set of questions, followed by a tabular listing of the appropriate differential considerations. The book emphasizes plain films, CT and some MR scans are integrated to demonstrate how these modalities enhance the work of a case

  2. [Recommendations for the selection of storage media for archiving digital radiological image data based on the comparison of retrieval times at different PACS archive levels].

    Science.gov (United States)

    Wirth, S; Treitl, M; Lucke, A; Mittermaier, I; Nissen-Meyer, S; Villain, S; Pfeifer, K-J; Reiser, M

    2005-02-01

    Recommendations for archiving digital radiological image data based on the comparison of retrieval times for different PACS archive levels. For a large PACS installation (Agfa Impax, Release 4.1), image retrieval times for radiological standard examinations (chest radiographs with 2, MRI with 250, CT with 100 and 1000 images; n = 120, each) from hard disk array, magneto-optical disk (MOD), and magnetic tape archives (TAPE) were examined in high and low network traffic load. Even large CT examinations (1000 images) were available from hard disk arrays within 4.0 +/- 0.8 s, smaller studies within 1.8 +/- 0.3 s. Radiographic image retrieval from MOD (30 +/- 4.7 s) was more then 50 % faster than from TAPE. For typical cross-sectional studies, the velocity gain amounted to 19 %. For both technologies, no significant difference was found for large CT examinations (651 +/- 144 s). For high and low network traffic load scenarios, image retrieval times from hard disk, MOD, and TAPE archives increased by 87 %, 7 %, and 22 %, respectively. Hard disk arrays are specifically suited as departmental intermediate storage media because they allow fast access to current and previous examinations within a short time. Performance properties enable both MOD and TAPE systems to serve as long-term archives. However, MOD archives are less flexible in the expansion of storage capacity and at present the medium costs per memory unit are about 2 - 3 times higher than for tape archives. The use of existing MOD-archives may be adequate as intermediate archives. For new PACS installations or system expansions, however, it is recommended to combine a sufficiently large local data memory (RAID) with data storage on tape archives outside the radiological unit that can be used by other departments as well. Future development of hard disk prices will show whether archiving for the whole data retention period may be handled by RAID systems. In any case, prefetching problems and waiting periods for

  3. Status of the Real-time On-line Decision Support (RODOS) system for off-site emergency management after nuclear and radiological accidents

    International Nuclear Information System (INIS)

    Raskov, W.; Ehrhardt, J.; Landman, C.; Pasler-Sauer, J.

    2006-01-01

    Under the auspices of its EURATOM Research Framework Programmes, the European Commission (EC) has supported the development of the comprehensive decision support system RODOS (Real-time On-line Decision Support) for off-site emergency management after nuclear accidents for more than a decade. Many national research programmes, research institutes and industrial collaborators contributed to the project, in particular the German Ministry of Environment, Nature Conservation and Reactor Safety (B MU). The RODOS system can be applied to accidental releases into the atmosphere and various aquatic environments within and across Europe. It provides coherent support before, during and after such a release to assist analysis of the situation and decision making about short and long-term countermeasures for mitigating the consequences with respect to health, the environment, and the economy. Appropriate interfaces exist with local and national radiological monitoring data systems, meteorological measurements and forecasts, and for the adaptation to local, regional and national conditions in Europe. Within the European Integrated Project EURANOS of the sixth Framework Programme, the RODOS system is being enhanced, among others, for radiological emergencies such as dirty bombs attacks, transport accidents and satellite crashes by extensions of the nuclide list, the source term characteristics and the atmospheric dispersion model

  4. Radiological protection report 2016

    International Nuclear Information System (INIS)

    2017-06-01

    on the basis of international recommendations. ENSI uses inspections and comparative measurements to ensure that the necessary calibrated radiological protection measurement equipment is available and that it is used for its intended purpose in order to determine correct values. For this purpose, it operates a test centre accredited to ISO 17025. The network operated by ENSI for automatically monitoring the dose rate in the vicinity of nuclear power plants measures dose rates in the vicinity of nuclear power stations all year round and 24 hours a day. The 10-minute, hourly and daily mean rates measured can be viewed on ENSI's web site in real time. This monitoring network serves to secure evidence for the authorities and in dealings with the public. No local increases in dose rates that could be attributed to discharges from nuclear power plants were detected in the reporting year. Sporadic, locally high measurements are due to fluctuations in natural background radiation, e.g. after rainfall. The programme JRODOS (Java-based Realtime Online DecisiOn Support system) has been used since the beginning of 2016 to model atmospheric spread and calculate the dose, should an event occur. JRODOS allows the direct use of 3D weather forecast data from the COSMO-1 model routinely used by MeteoSwiss with a grid size of 1 km. The COSMO-1 model supplies forecasts stretching up to 24 hours into the future with high spatial and temporal resolution. In order to reflect the small scale structure of the Swiss countryside and that of southern Germany, JRODOS uses the very high resolution elevation model from the Swiss Federal Office of Topography. This means that together with the aerial radiometric equipment, there are invaluable, precise instruments available at all times for making current assessments (diagnoses) as well as forecasts of the radiological situation. In the reporting year, all thresholds contained in the Federal Ordinance on radiation protection were met. There

  5. Does expressive timing in music performance scale proportionally with tempo?

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1994-01-01

    Evidence is presented that expressive timing in music is not relationally invariant with global tempo. Our results stem from an analysis of repeated performances of Beethoven's variations on a Paisiello theme. Recordings were made of two pianists playing the pieces at three tempi. In contrast with

  6. Perception of short time scale intervals in a hypnotic virtuoso

    NARCIS (Netherlands)

    Noreika, Valdas; Falter, Christine M.; Arstila, Valtteri; Wearden, John H.; Kallio, Sakari

    2012-01-01

    Previous studies showed that hypnotized individuals underestimate temporal intervals in the range of several seconds to tens of minutes. However, no previous work has investigated whether duration perception is equally disorderly when shorter time intervals are probed. In this study, duration

  7. Coherent spectroscopies on ultrashort time and length scales

    Directory of Open Access Journals (Sweden)

    Schneider C.

    2013-03-01

    Full Text Available Three spectroscopic techniques are presented that provide simultaneous spatial and temporal resolution: modified confocal microscopy with heterodyne detection, space-time-resolved spectroscopy using coherent control concepts, and coherent two-dimensional nano-spectroscopy. Latest experimental results are discussed.

  8. Modelling financial markets with agents competing on different time scales and with different amount of information

    Science.gov (United States)

    Wohlmuth, Johannes; Andersen, Jørgen Vitting

    2006-05-01

    We use agent-based models to study the competition among investors who use trading strategies with different amount of information and with different time scales. We find that mixing agents that trade on the same time scale but with different amount of information has a stabilizing impact on the large and extreme fluctuations of the market. Traders with the most information are found to be more likely to arbitrage traders who use less information in the decision making. On the other hand, introducing investors who act on two different time scales has a destabilizing effect on the large and extreme price movements, increasing the volatility of the market. Closeness in time scale used in the decision making is found to facilitate the creation of local trends. The larger the overlap in commonly shared information the more the traders in a mixed system with different time scales are found to profit from the presence of traders acting at another time scale than themselves.

  9. Perception of short time scale intervals in a hypnotic virtuoso.

    Science.gov (United States)

    Noreika, Valdas; Falter, Christine M; Arstila, Valtteri; Wearden, John H; Kallio, Sakari

    2012-01-01

    Previous studies showed that hypnotized individuals underestimate temporal intervals in the range of several seconds to tens of minutes. However, no previous work has investigated whether duration perception is equally disorderly when shorter time intervals are probed. In this study, duration perception of a hypnotic virtuoso was tested using repeated standard temporal generalization and duration estimation tasks. When compared to the baseline state, hypnosis affected perception of intervals spread around 600 ms in the temporal generalization task but did not alter perception of slightly longer intervals spread around 1000 ms. Furthermore, generalization of temporal intervals was more orderly under hypnosis than in the baseline state. In contrast, the hypnotic virtuoso showed a typical time underestimation effect when perception of longer supra-second intervals was tested in the duration estimation task, replicating results of the previous hypnosis studies.

  10. Time-scale invariance as an emergent property in a perceptron with realistic, noisy neurons.

    Science.gov (United States)

    Buhusi, Catalin V; Oprisan, Sorinel A

    2013-05-01

    In most species, interval timing is time-scale invariant: errors in time estimation scale up linearly with the estimated duration. In mammals, time-scale invariance is ubiquitous over behavioral, lesion, and pharmacological manipulations. For example, dopaminergic drugs induce an immediate, whereas cholinergic drugs induce a gradual, scalar change in timing. Behavioral theories posit that time-scale invariance derives from particular computations, rules, or coding schemes. In contrast, we discuss a simple neural circuit, the perceptron, whose output neurons fire in a clockwise fashion based on the pattern of coincidental activation of its input neurons. We show numerically that time-scale invariance emerges spontaneously in a perceptron with realistic neurons, in the presence of noise. Under the assumption that dopaminergic drugs modulate the firing of input neurons, and that cholinergic drugs modulate the memory representation of the criterion time, we show that a perceptron with realistic neurons reproduces the pharmacological clock and memory patterns, and their time-scale invariance, in the presence of noise. These results suggest that rather than being a signature of higher order cognitive processes or specific computations related to timing, time-scale invariance may spontaneously emerge in a massively connected brain from the intrinsic noise of neurons and circuits, thus providing the simplest explanation for the ubiquity of scale invariance of interval timing. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. A Study on Time-Scales Ratio and Turbulent Prandtl Number in Ducts of Industrial Applications

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2006-01-01

    is solved using a two-equation heat flux model. The computed results compare satisfactory with the available experimental data. The time-scale ratio R is defined as the ratio between the dynamic time-scale (k/ε) and the scalar time-scale(0.5θθ/εθ). Based on existing DNS data and calculations in this work...... of heat exchangers for various applications area....

  12. Long time scale simulation of a grain boundary in copper

    DEFF Research Database (Denmark)

    Pedersen, A.; Henkelman, G.; Schiøtz, Jakob

    2009-01-01

    A general, twisted and tilted, grain boundary in copper has been simulated using the adaptive kinetic Monte Carlo method to study the atomistic structure of the non-crystalline region and the mechanism of annealing events that occur at low temperature. The simulated time interval spanned 67 mu s...... was also observed. In the final low-energy configurations, the thickness of the region separating the crystalline grains corresponds to just one atomic layer, in good agreement with reported experimental observations. The simulated system consists of 1307 atoms and atomic interactions were described using...

  13. Diagnostic radiology 1987

    International Nuclear Information System (INIS)

    Margulis, A.R.; Gooding, C.A.

    1987-01-01

    This is the latest version of the continuing education course on diagnostic radiology given yearly by the Department of Radiology at the University of California, San Francisco. The lectures are grouped into sections on gastrointestinal radiology, mammography, uroradiology, magnetic resonance, hepatobiliary radiology, pediatric radiology, ultrasound, interventional radiology, chest radiology, nuclear medicine, cardiovascular radiology, and skeletal radiology. Each section contains four to eight topics. Each of these consists of text that represents highlights in narrative form, selected illustrations, and a short bibliography. The presentation gives a general idea of what points were made in the lecture

  14. Temperature Responses to Spectral Solar Variability on Decadal Time Scales

    Science.gov (United States)

    Cahalan, Robert F.; Wen, Guoyong; Harder, Jerald W.; Pilewskie, Peter

    2010-01-01

    Two scenarios of spectral solar forcing, namely Spectral Irradiance Monitor (SIM)-based out-of-phase variations and conventional in-phase variations, are input to a time-dependent radiative-convective model (RCM), and to the GISS modelE. Both scenarios and models give maximum temperature responses in the upper stratosphere, decreasing to the surface. Upper stratospheric peak-to-peak responses to out-of-phase forcing are approx.0.6 K and approx.0.9 K in RCM and modelE, approx.5 times larger than responses to in-phase forcing. Stratospheric responses are in-phase with TSI and UV variations, and resemble HALOE observed 11-year temperature variations. For in-phase forcing, ocean mixed layer response lags surface air response by approx.2 years, and is approx.0.06 K compared to approx.0.14 K for atmosphere. For out-of-phase forcing, lags are similar, but surface responses are significantly smaller. For both scenarios, modelE surface responses are less than 0.1 K in the tropics, and display similar patterns over oceanic regions, but complex responses over land.

  15. Analysis of the Radiology Reports from Radiology Clinics

    International Nuclear Information System (INIS)

    Kim, Eun Jin; Kwack, Kyu Sung; Cho, Jae Hyun; Jang, Eun Ho

    2009-01-01

    The purpose of this study was to investigate the form and content of the radiology reports from radiology clinics in Korea. One hundred and sixty six radiology reports from 49 radiology clinics were collected, and these reports were referred to the academic tertiary medical center from March 2008 to February 2009. These included reports for CT (n = 18), MRI (n = 146) and examinations not specified (n = 2). Each report was evaluated for the presence of required contents (demographics, technical information, findings, conclusion, the name, license number and signature of the radiologist and the referring facility). These requirements were based on the guideline of the American College of Radiology and the previous research. The name of the patient, the gender, the body part, the type of examination, the time of examination and the conclusion, the name of the radiologist and the name of facility were well recorded in over 90% of the radiology reports. However, the identification number of the patient, the referring facility, the referring physician, the use of contrast material, the clinical information, the time of dictation, the signature of the radiologist and the license number of the radiologist were poorly recorded (less than 50%). The optimal format of a radiology report should be established for reliable and valid communication with clinicians

  16. Global Exponential Stability of Delayed Cohen-Grossberg BAM Neural Networks with Impulses on Time Scales

    Directory of Open Access Journals (Sweden)

    Fei Yu

    2009-01-01

    Full Text Available Based on the theory of calculus on time scales, the homeomorphism theory, Lyapunov functional method, and some analysis techniques, sufficient conditions are obtained for the existence, uniqueness, and global exponential stability of the equilibrium point of Cohen-Grossberg bidirectional associative memory (BAM neural networks with distributed delays and impulses on time scales. This is the first time applying the time-scale calculus theory to unify the discrete-time and continuous-time Cohen-Grossberg BAM neural network with impulses under the same framework.

  17. A Novel Multiple-Time Scale Integrator for the Hybrid Monte Carlo Algorithm

    International Nuclear Information System (INIS)

    Kamleh, Waseem

    2011-01-01

    Hybrid Monte Carlo simulations that implement the fermion action using multiple terms are commonly used. By the nature of their formulation they involve multiple integration time scales in the evolution of the system through simulation time. These different scales are usually dealt with by the Sexton-Weingarten nested leapfrog integrator. In this scheme the choice of time scales is somewhat restricted as each time step must be an exact multiple of the next smallest scale in the sequence. A novel generalisation of the nested leapfrog integrator is introduced which allows for far greater flexibility in the choice of time scales, as each scale now must only be an exact multiple of the smallest step size.

  18. 2005 Program of Study: Fast Times and Fine Scales

    Science.gov (United States)

    2006-07-01

    8217, (2.5) and the space time average, (F) F(x)ddx. (2.6) From here on our domain will be a periodic box of size L, i.e. x C Td , the d-dimensional torus...variance for s(x) = sin ksxl and x c Td i.e., x E [0, L]d, is saturated by the sweeping flow suggested by W. R. Young. Consider the steady advection...2 47 2 +3F -y 2 ,.YI2 (472 + 3F) 3F ( IYr + _Y2) 8 (Z + y2 Z’) K(- _C)2± (U, +C) 2 + C -C S3y2 IYl2 Z’ 3Z ( 2] (41) 240 where Z -3 + 2FU, *r K__c (Uvc

  19. Time scales and the problem of radioactive waste

    International Nuclear Information System (INIS)

    Goble, R.L.

    1984-01-01

    The author argues that decisions about future nuclear development can be made essentially independent of waste management considerations for the next 20 years. His arguments are based on five propositions: 1 Risks and costs of storing spent fuel or high-level waste and transuranics are lower than other directly comparable risks and costs of operating a reactor. 2 Storage of mill tailings is the most serious long-term waste problem; it is not serious enough to rule out the use of nuclear power. 3 There are compelling reasons for beginning to implement a waste management program now. 4 It is important to separate the problem of providing temporary storage from that of finding permanent repositories. 5 A prudent waste management strategy, by 2000, will have identified and evaluated more than enough repository space for the waste generated by that time, independent of the decision made about nuclear futures. 13 references, 4 figures, 4 tables

  20. Pediatric radiology

    International Nuclear Information System (INIS)

    Kirkpatrick, J.A. Jr.

    1985-01-01

    Computed tomography has made possible the excellent and basic work having to do with the characteristics of the trachea, its caliber, shape, and length in children. Another group of articles has to do with interventional pediatric radiology. This year there were a number of articles of which only a sample is included, dealing with therapeutic procedures involving drainage of abscesses, angioplasty, nephrostomy, therapeutic embolization, and the removal of esophageal foreign bodies. Obviously, there is no reason to think that techniques developed for the adult may not be applicable to the infant or child; also, there is no reason to believe that processes peculiar to the child should not be amenable to intervention, for instance, use of embolization of hepatic hemangioma and transluminal balloon valvuloplasty for pulmonary valvular stenosis. Among the reports and reviews, the author would add that sonography remains a basic imaging technique in pediatric radiology and each year its application broadens. For example, there is an excellent article having to do with sonography of the neonatal and infant hip and evaluation of the inferior vena cava and the gallbladder. Nuclear medicine continues to play a significant role in diagnosis, which is featured in two articles concerned with problems of the hip

  1. RECENT GEODYNAMICS OF FAULT ZONES: FAULTING IN REAL TIME SCALE

    Directory of Open Access Journals (Sweden)

    Yu. O. Kuzmin

    2014-01-01

    Full Text Available Recent deformation processes taking place in real time are analyzed on the basis of data on fault zones which were collected by long-term detailed geodetic survey studies with application of field methods and satellite monitoring.A new category of recent crustal movements is described and termed as parametrically induced tectonic strain in fault zones. It is shown that in the fault zones located in seismically active and aseismic regions, super intensive displacements of the crust (5 to 7 cm per year, i.e. (5 to 7·10–5 per year occur due to very small external impacts of natural or technogenic / industrial origin.The spatial discreteness of anomalous deformation processes is established along the strike of the regional Rechitsky fault in the Pripyat basin. It is concluded that recent anomalous activity of the fault zones needs to be taken into account in defining regional regularities of geodynamic processes on the basis of real-time measurements.The paper presents results of analyses of data collected by long-term (20 to 50 years geodetic surveys in highly seismically active regions of Kopetdag, Kamchatka and California. It is evidenced by instrumental geodetic measurements of recent vertical and horizontal displacements in fault zones that deformations are ‘paradoxically’ deviating from the inherited movements of the past geological periods.In terms of the recent geodynamics, the ‘paradoxes’ of high and low strain velocities are related to a reliable empirical fact of the presence of extremely high local velocities of deformations in the fault zones (about 10–5 per year and above, which take place at the background of slow regional deformations which velocities are lower by the order of 2 to 3. Very low average annual velocities of horizontal deformation are recorded in the seismic regions of Kopetdag and Kamchatka and in the San Andreas fault zone; they amount to only 3 to 5 amplitudes of the earth tidal deformations per year.A

  2. Marine Dispersal Scales Are Congruent over Evolutionary and Ecological Time

    KAUST Repository

    Pinsky, Malin L.

    2016-12-15

    The degree to which offspring remain near their parents or disperse widely is critical for understanding population dynamics, evolution, and biogeography, and for designing conservation actions. In the ocean, most estimates suggesting short-distance dispersal are based on direct ecological observations of dispersing individuals, while indirect evolutionary estimates often suggest substantially greater homogeneity among populations. Reconciling these two approaches and their seemingly competing perspectives on dispersal has been a major challenge. Here we show for the first time that evolutionary and ecological measures of larval dispersal can closely agree by using both to estimate the distribution of dispersal distances. In orange clownfish (Amphiprion percula) populations in Kimbe Bay, Papua New Guinea, we found that evolutionary dispersal kernels were 17 km (95% confidence interval: 12–24 km) wide, while an exhaustive set of direct larval dispersal observations suggested kernel widths of 27 km (19–36 km) or 19 km (15–27 km) across two years. The similarity between these two approaches suggests that ecological and evolutionary dispersal kernels can be equivalent, and that the apparent disagreement between direct and indirect measurements can be overcome. Our results suggest that carefully applied evolutionary methods, which are often less expensive, can be broadly relevant for understanding ecological dispersal across the tree of life.

  3. Neural Computations in a Dynamical System with Multiple Time Scales

    Directory of Open Access Journals (Sweden)

    Yuanyuan Mi

    2016-09-01

    Full Text Available Neural systems display rich short-term dynamics at various levels, e.g., spike-frequencyadaptation (SFA at single neurons, and short-term facilitation (STF and depression (STDat neuronal synapses. These dynamical features typically covers a broad range of time scalesand exhibit large diversity in different brain regions. It remains unclear what the computationalbenefit for the brain to have such variability in short-term dynamics is. In this study, we proposethat the brain can exploit such dynamical features to implement multiple seemingly contradictorycomputations in a single neural circuit. To demonstrate this idea, we use continuous attractorneural network (CANN as a working model and include STF, SFA and STD with increasing timeconstants in their dynamics. Three computational tasks are considered, which are persistent activity,adaptation, and anticipative tracking. These tasks require conflicting neural mechanisms, andhence cannot be implemented by a single dynamical feature or any combination with similar timeconstants. However, with properly coordinated STF, SFA and STD, we show that the network isable to implement the three computational tasks concurrently. We hope this study will shed lighton the understanding of how the brain orchestrates its rich dynamics at various levels to realizediverse cognitive functions.

  4. Updating the planetary time scale: focus on Mars

    Science.gov (United States)

    Tanaka, Kenneth L.; Quantin-Nataf, Cathy

    2013-01-01

    Formal stratigraphic systems have been developed for the surface materials of the Moon, Mars, Mercury, and the Galilean satellite Ganymede. These systems are based on geologic mapping, which establishes relative ages of surfaces delineated by superposition, morphology, impact crater densities, and other relations and features. Referent units selected from the mapping determine time-stratigraphic bases and/or representative materials characteristic of events and periods for definition of chronologic units. Absolute ages of these units in some cases can be estimated using crater size-frequency data. For the Moon, the chronologic units and cratering record are calibrated by radiometric ages measured from samples collected from the lunar surface. Model ages for other cratered planetary surfaces are constructed primarily by estimating cratering rates relative to that of the Moon. Other cratered bodies with estimated surface ages include Venus and the Galilean satellites of Jupiter. New global geologic mapping and crater dating studies of Mars are resulting in more accurate and detailed reconstructions of its geologic history.

  5. Pilot Study of a Patient-Centered Radiology Process Model.

    Science.gov (United States)

    Swan, J Shannon; Furtado, Vanessa F; Keller, Lisa A; Lotti, Judith Borsody; Saltalamacchia, Catherine A; Lennes, Inga T; Salazar, Gloria M

    2017-02-01

    The Radiology Process Model (RPM) was previously described in terms of its conceptual basis and proposed survey items. The current study describes the first pilot application of the RPM in the field and the results of initial psychometric analysis. We used an Institutional Review Board-approved pilot RPM survey in 100 patients having outpatient interventional radiology procedures. The 24 survey items had 4 or 5 levels of severity. We assessed for missing data, items that patients found confusing, any suggestions by patients for additional items and clarity of items from patient feedback. Factor analysis was performed and internal consistency measured. Construct validity was assessed by correlation of patient responses to the items as a summated scale with a visual analog scale (VAS) they completed indicating their interventional radiology experience. The visual analog scale and the RPM summated scale were strongly correlated (r = 0.7). Factor analysis showed four factors: interactions with facility and doctors/staff, time-sensitive aspects, pain, and anxiety. The items showed high internal consistency (alpha: 0.86) as a group and approximately 0.7 to 0.9 by the factors. Analysis shows that two items could be deleted (cost and communication between radiologist and referrers). Revision of two items and potential addition of others are discussed. The RPM shows initial evidence of psychometric validity and internal consistency reliability. Minor changes are anticipated before wider use. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  6. Freshwater flushing time scales of the Vashishti Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Sarma, R.V.; Zingde, M.D.

    Results are presented for the Vashishti estuary, Kerala, India to evaluate its freshwater flushing time scales based on 8 sets of observations of longitudinal salinity distributions. The results of the flushing time using the fraction of freshwater...

  7. Radiology report turnaround: expectations and solutions.

    Science.gov (United States)

    Boland, G W L; Guimaraes, A S; Mueller, P R

    2008-07-01

    The ultimate work product of a radiology department is a finalized radiology report. Radiology stakeholders are now demanding faster report turnaround times (RTAT) and anything that delays delivery of the finalized report will undermine the value of a radiology department. Traditional reporting methods are inherently inefficient and the desire to deliver fast RTAT will always be challenged. It is only through the adoption of an integrated radiology information system (RIS)/picture archiving and communication system (PACS) and voice recognition (VR) system that RTAT can consistently meet stakeholder expectations. VR systems also offer the opportunity to create standardized, higher quality reports.

  8. The German Radiological Society and the protagonists of radiology during the time of National Socialism. State of research, explanation attempts, desiderata and research prospects; Die Deutsche Roentgengesellschaft und die Protagonisten der Radiologie in der Zeit des Nationalsozialismus. Forschungsstand, Erklaerungsansaetze, Desiderate und Perspektiven

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, M.; Winzen, T.; Gross, D. [RWTH Aachen University Medical School, Aachen (Germany). Inst. of the History, Theory and Ethics of Medicine

    2015-06-15

    The intention of the authors is the recognition and critical analysis of efforts to study the history of the German Radiological Society during the time of National Socialism from 1933 to 1945 with the goal of determining existing desiderata and identifying the resulting research prospects. There is a need to study concrete individual biographies of radiologists (members of the German Radiological Society, perpetrators, and victims) and their careers before and after 1945 as well as the importance of the interdisciplinarity of the discipline and the lack of institutional involvement during the ''Third Reich''. Moreover, the comparatively difficult starting situation of the study of the history of the German Radiological Society is discussed.

  9. Glottal closure instant and voice source analysis using time-scale ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... 1Time-scale representation of voiced speech is applied to voice quality analysis, by introducing the Line of Maximum Amplitude (LoMA) method. This representation takes advantage of the tree patterns observed for voiced speech periods in the time-scale domain. For each period, the optimal LoMA is ...

  10. Measurement Invariance of the Perceived Stress Scale and Latent Mean Differences across Gender and Time

    NARCIS (Netherlands)

    Barbosa-Leiker, C.; Kostick, M.; Lei, M.; McPherson, S.; Roper, V.; Hoekstra, T.; Wright, B.

    2013-01-01

    Measurement invariance of the 2-factor model of the Perceived Stress Scale - 10-item version (Cohen & Williamson, 1988) was tested across men and women at two time points and in the combined total sample over a 2-year time frame (n = 871). Measurement invariance results indicated that the scale

  11. Breath-hold times in patients undergoing radiological examinations. Comparison of expiration and inspiration with and without hyperventilation

    International Nuclear Information System (INIS)

    Groell, R.; Schaffler, G.J.; Schloffer, S.

    2001-01-01

    Background. Breath-holding is necessary for imaging studies of the thorax and abdomen using computed tomography, magnetic resonance imaging or ultrasound examinations. The purpose of this study was to compare the breath-hold times in expiration and inspiration and to evaluate the effects of hyperventilation. Patients and methods. Thirty patients and 19 healthy volunteers participated in this study after informed consent was obtained in all. The breath-hold times were measured in expiration and inspiration before and after hyperventilation. Results. The mean breath-hold times in expiration (patients: 24±9 sec, volunteers: 27±7 sec) were significantly shorter than those in inspiration (patients: 41±20 sec, p<0.001; volunteers: 62±18 sec, p<0.001). Additional hyperventilation resulted in a significant increase (range: 40-60%, p≤0.005) of the mean breathhold times either in expiration and in inspiration and for both patients and volunteers. Conclusions. Although breath-holding in expiration is recommended for various imaging studies particularly of the thorax and of the abdomen, suspending respiration in inspiration enables the patient a considerable longer breath-hold time. (author)

  12. Quantifying catchment-scale mixing and its effect on time-varying travel time distributions

    NARCIS (Netherlands)

    Van Der Velde, Y.; Torfs, P. J J F; Van Der Zee, S. E A T M; Uijlenhoet, R.

    2012-01-01

    Travel time distributions are often used to characterize catchment discharge behavior, catchment vulnerability to pollution and pollutant loads from catchments to downstream waters. However, these distributions vary with time because they are a function of rainfall and evapotranspiration. It is

  13. Radiologic protection in dental radiology

    International Nuclear Information System (INIS)

    Pacheco Jimenez, R.E.; Bermudez Jimenez, L.A.

    2000-01-01

    With this work and employing the radioprotection criterion, the authors pretend to minimize the risks associated to this practice; without losing the quality of the radiologic image. Odontology should perform the following criterions: 1. Justification: all operation of practice that implies exposition to radiations, should be reweighed, through an analysis of risks versus benefits, with the purpose to assure, that the total detriment will be small, compared to resultant benefit of this activity. 2. Optimization: all of the exposures should be maintained as low as reasonable possible, considering the social and economic factors. 3. Dose limit: any dose limit system should be considered as a top condition, nota as an admissible level. (S. Grainger)

  14. Shielding of optical pulses on hydrodynamical time scales in laser-induced breakdown of saline water

    OpenAIRE

    Conti, Daniel; Marino, Francesco; Roati, Giacomo; Orfila, Alejandro; Javaloyes, Julien; Piro, Oreste; Balle, Salvador

    2014-01-01

    Pulse shielding in Laser-Induced Breakdown of saline water on hydrodynamic time scales is experimentally characterized. Pairs of pulses from a Nd:YAG laser are focused into saline water with a controlled time delay between them. The Laser-Induced Breakdown produced by the first pulse creates a cavitation bubble that later collapses generating a plume of bubbles that evolves on hydrodynamic time scales. When the second pulse arrives, the light is scattered by this plume with a consequent reduc...

  15. Modelling soil carbon movement by erosion over large scales and long time periods

    Science.gov (United States)

    Quinton, John; Davies, Jessica; Tipping, Ed

    2014-05-01

    Agricultural intensification accelerates physical erosion rates and the transport of carbon within the landscape. In order to improve understanding of how past, present and future anthropogenic land-use change has and will influence carbon and nutrient cycling, it is necessary to develop quantitative tools that can predict soil erosion and carbon movement at large temporal and spatial scales, that are consistent with the time constants of biogeochemical processes and the spatial scales of land-use change and natural resources. However, representing erosion and its impact on the carbon cycle over large spatial scales and long time periods is challenging. Erosion and sediment transport processes operate at multiple spatial and temporal scales with splash erosion dominating at the sub-plot scale and occurring within seconds, up to gully formation operating at field-catchment scales over days to months. In addition, most erosion production observations are made at the experimental plot scale, where fine time scales and detailed processes dominate. This is coupled with complexities associated with carbon detachment, decomposition and uncertainties surrounding carbon burial rates and stability - all of which occur over widely different temporal and spatial scales. As such, these data cannot be simply scaled to inform erosion and carbon representation at the regional scale, where topography, vegetation cover and landscape organisation become more important controls on sediment fluxes. We have developed a simple energy-based regional scale method of soil erosion modelling, which is integration into a hydro-biogeochemical model that will simulate carbon, nitrogen and phosphorus pools and fluxes across the UK from the industrial revolution to the present day. The model is driven by overland flow, dynamic vegetation cover, soil properties, and topographic distributions and produces sediment production and yield at the 5km grid scale. In this paper we will introduce the

  16. Effect of helicity on the correlation time of large scales in turbulent flows

    Science.gov (United States)

    Cameron, Alexandre; Alexakis, Alexandros; Brachet, Marc-Étienne

    2017-11-01

    Solutions of the forced Navier-Stokes equation have been conjectured to thermalize at scales larger than the forcing scale, similar to an absolute equilibrium obtained for the spectrally truncated Euler equation. Using direct numeric simulations of Taylor-Green flows and general-periodic helical flows, we present results on the probability density function, energy spectrum, autocorrelation function, and correlation time that compare the two systems. In the case of highly helical flows, we derive an analytic expression describing the correlation time for the absolute equilibrium of helical flows that is different from the E-1 /2k-1 scaling law of weakly helical flows. This model predicts a new helicity-based scaling law for the correlation time as τ (k ) ˜H-1 /2k-1 /2 . This scaling law is verified in simulations of the truncated Euler equation. In simulations of the Navier-Stokes equations the large-scale modes of forced Taylor-Green symmetric flows (with zero total helicity and large separation of scales) follow the same properties as absolute equilibrium including a τ (k ) ˜E-1 /2k-1 scaling for the correlation time. General-periodic helical flows also show similarities between the two systems; however, the largest scales of the forced flows deviate from the absolute equilibrium solutions.

  17. Studying the time scale dependence of environmental variables predictability using fractal analysis.

    Science.gov (United States)

    Yuval; Broday, David M

    2010-06-15

    Prediction of meteorological and air quality variables motivates a lot of research in the atmospheric sciences and exposure assessment communities. An interesting related issue regards the relative predictive power that can be expected at different time scales, and whether it vanishes altogether at certain ranges. An improved understanding of our predictive powers enables better environmental management and more efficient decision making processes. Fractal analysis is commonly used to characterize the self-affinity of time series. This work introduces the Continuous Wavelet Transform (CWT) fractal analysis method as a tool for assessing environmental time series predictability. The high temporal scale resolution of the CWT enables detailed information about the Hurst parameter, a common temporal fractality measure, and thus about time scale variations in predictability. We analyzed a few years records of half-hourly air pollution and meteorological time series from which the trivial seasonal and daily cycles were removed. We encountered a general trend of decreasing Hurst values from about 1.4 (good autocorrelation and predictability), in the sub-daily time scale to 0.5 (which implies complete randomness) in the monthly to seasonal scales. The air pollutants predictability follows that of the meteorological variables in the short time scales but is better at longer scales.

  18. Diagnostic accuracy of the Barr and Blethyn radiological scoring systems for childhood constipation assessed using colonic transit time as the gold standard

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Claire R.; Wylie, Anna B.Z.; Adams, Charlotte [Royal Victoria Infirmary, Department of Paediatric Surgery, Newcastle upon Tyne (United Kingdom); Lee, Richard E. [Royal Victoria Infirmary, Department of Radiology, Newcastle upon Tyne (United Kingdom); Jaffray, Bruce [University of Newcastle upon Tyne, School of Clinical Medical Sciences (Child Health), Sir James Spence Institute, Newcastle upon Tyne (United Kingdom)

    2009-07-15

    Constipation is a common childhood symptom and abdominal radiography is advocated in diagnosis and management. To assess the reproducibility and diagnostic accuracy of the Barr and Blethyn systems for quantifying constipation on abdominal radiographs in children. Radiographs were scored by three observers of increasing radiological experience (student, junior doctor, consultant). Abdominal radiographs produced during measurement of colonic transit time (CTT) were classified as constipated or normal based on the value of the transit time, and were scored using both systems by observers blinded to the CTT. Abdominal radiographs obtained in children for reasons other than constipation were classed as normal and similarly scored. Reproducibility was measured using the kappa statistic. Diagnostic accuracy was measured using the area under the curve (AUC) for the receiver operator characteristic (ROC) curve. Using either system, scores were higher for constipated children (P<0.01). The consultant produced higher scores than the other observers (P<0.01). Interobserver reproducibility was moderate with the best kappa value only 0.48. The best correlation between score and CTT was 0.51 (junior doctor scores). Diagnostic accuracy of the scores was only moderate, with the largest AUC for a ROC curve of 0.84 for the consultant using the Barr score. Scoring of abdominal radiographs in the assessment of childhood constipation should be abandoned because it is dependent on the experience of the observer, is poorly reproducible, and does not accurately discriminate between constipated children and children without constipation. (orig.)

  19. Diagnostic accuracy of the Barr and Blethyn radiological scoring systems for childhood constipation assessed using colonic transit time as the gold standard

    International Nuclear Information System (INIS)

    Jackson, Claire R.; Wylie, Anna B.Z.; Adams, Charlotte; Lee, Richard E.; Jaffray, Bruce

    2009-01-01

    Constipation is a common childhood symptom and abdominal radiography is advocated in diagnosis and management. To assess the reproducibility and diagnostic accuracy of the Barr and Blethyn systems for quantifying constipation on abdominal radiographs in children. Radiographs were scored by three observers of increasing radiological experience (student, junior doctor, consultant). Abdominal radiographs produced during measurement of colonic transit time (CTT) were classified as constipated or normal based on the value of the transit time, and were scored using both systems by observers blinded to the CTT. Abdominal radiographs obtained in children for reasons other than constipation were classed as normal and similarly scored. Reproducibility was measured using the kappa statistic. Diagnostic accuracy was measured using the area under the curve (AUC) for the receiver operator characteristic (ROC) curve. Using either system, scores were higher for constipated children (P<0.01). The consultant produced higher scores than the other observers (P<0.01). Interobserver reproducibility was moderate with the best kappa value only 0.48. The best correlation between score and CTT was 0.51 (junior doctor scores). Diagnostic accuracy of the scores was only moderate, with the largest AUC for a ROC curve of 0.84 for the consultant using the Barr score. Scoring of abdominal radiographs in the assessment of childhood constipation should be abandoned because it is dependent on the experience of the observer, is poorly reproducible, and does not accurately discriminate between constipated children and children without constipation. (orig.)

  20. Docritfab: A program to assess the radiological impact in accidental emissions of a nuclear fuel factory in real time; Docritfab: Un programa para evaluar en tiempo real el impacto radiologico en emisiones accidentales de una fabrica de combustible nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J. G.; Ortiz, D.; Lopez, J.

    2014-07-01

    Docrit is a program developed for the manufacture of fuels of oxides of uranium Juzbado allowing an estimate in real time of the radiological impact in the case of accidental emissions from gaseous effluents (emissions of aerosols of UO{sub 2} and criticality accidents).

  1. Off-Policy Reinforcement Learning: Optimal Operational Control for Two-Time-Scale Industrial Processes.

    Science.gov (United States)

    Li, Jinna; Kiumarsi, Bahare; Chai, Tianyou; Lewis, Frank L; Fan, Jialu

    2017-12-01

    Industrial flow lines are composed of unit processes operating on a fast time scale and performance measurements known as operational indices measured at a slower time scale. This paper presents a model-free optimal solution to a class of two time-scale industrial processes using off-policy reinforcement learning (RL). First, the lower-layer unit process control loop with a fast sampling period and the upper-layer operational index dynamics at a slow time scale are modeled. Second, a general optimal operational control problem is formulated to optimally prescribe the set-points for the unit industrial process. Then, a zero-sum game off-policy RL algorithm is developed to find the optimal set-points by using data measured in real-time. Finally, a simulation experiment is employed for an industrial flotation process to show the effectiveness of the proposed method.

  2. Super-transient scaling in time-delay autonomous Boolean network motifs

    Energy Technology Data Exchange (ETDEWEB)

    D' Huys, Otti, E-mail: otti.dhuys@phy.duke.edu; Haynes, Nicholas D. [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Lohmann, Johannes [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin (Germany); Gauthier, Daniel J. [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)

    2016-09-15

    Autonomous Boolean networks are commonly used to model the dynamics of gene regulatory networks and allow for the prediction of stable dynamical attractors. However, most models do not account for time delays along the network links and noise, which are crucial features of real biological systems. Concentrating on two paradigmatic motifs, the toggle switch and the repressilator, we develop an experimental testbed that explicitly includes both inter-node time delays and noise using digital logic elements on field-programmable gate arrays. We observe transients that last millions to billions of characteristic time scales and scale exponentially with the amount of time delays between nodes, a phenomenon known as super-transient scaling. We develop a hybrid model that includes time delays along network links and allows for stochastic variation in the delays. Using this model, we explain the observed super-transient scaling of both motifs and recreate the experimentally measured transient distributions.

  3. REAL-TIME VIDEO SCALING BASED ON CONVOLUTION NEURAL NETWORK ARCHITECTURE

    OpenAIRE

    S Safinaz; A V Ravi Kumar

    2017-01-01

    In recent years, video super resolution techniques becomes mandatory requirements to get high resolution videos. Many super resolution techniques researched but still video super resolution or scaling is a vital challenge. In this paper, we have presented a real-time video scaling based on convolution neural network architecture to eliminate the blurriness in the images and video frames and to provide better reconstruction quality while scaling of large datasets from lower resolution frames t...

  4. A time-scale analysis of systematic risk: wavelet-based approach

    OpenAIRE

    Khalfaoui Rabeh, K; Boutahar Mohamed, B

    2011-01-01

    The paper studies the impact of different time-scales on the market risk of individual stock market returns and of a given portfolio in Paris Stock Market by applying the wavelet analysis. To investigate the scaling properties of stock market returns and the lead/lag relationship between them at different scales, wavelet variance and crosscorrelations analyses are used. According to wavelet variance, stock returns exhibit long memory dynamics. The wavelet cross-correlation analysis s...

  5. Radiologic protection in pediatric radiology: ICRP recommendations

    International Nuclear Information System (INIS)

    Sanchez, Ramon; Khong, Pek-Lan; Ringertz, Hans

    2013-01-01

    ICRP has provided an updated overview of radiation protection principles in pediatric radiology. The authors recommend that staff, radiologists, medical physicists and vendors involved in pediatric radiology read this document. For conventional radiography, the report gives advice on patient positioning, immobilization, shielding and appropriate exposure conditions. It describes extensively the use of pulsed fluoroscopy, the importance of limiting fluoroscopy time, and how shielding and geometry must be used to avoid unnecessary radiation to the patient and operator. Furthermore, the use of fluoroscopy in interventional procedures with emphasis on dose reduction to patients and staff is discussed in light of the increasing frequency, complexity and length ofthe procedures. CT is the main reason that medical imaging in several developed countries is the highest annual per capita effective radiation dose from man-made sources. The ICRP report gives extensive descriptions of how CT protocols can be optimized to minimize radiation exposure in pediatric patients. The importance of balancing image quality with acceptable noise in pediatric imaging and the controversies regarding the use of protective shielding in CT are also discussed.

  6. Radiologic protection in pediatric radiology: ICRP recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Ramon [University of Michigan Hospital, Department of Radiology, C. S. Mott Children' s Hospital, Ann Arbor, MI (United States); Khong, Pek-Lan [The University of Hong Kong, Department of Diagnostic Radiology, Queen Mary Hospital, Hong Kong (China); Ringertz, Hans [Linkoeping University Hospital, Center for Medical Image Science and Visualization, Linkoeping (Sweden)

    2013-08-15

    ICRP has provided an updated overview of radiation protection principles in pediatric radiology. The authors recommend that staff, radiologists, medical physicists and vendors involved in pediatric radiology read this document. For conventional radiography, the report gives advice on patient positioning, immobilization, shielding and appropriate exposure conditions. It describes extensively the use of pulsed fluoroscopy, the importance of limiting fluoroscopy time, and how shielding and geometry must be used to avoid unnecessary radiation to the patient and operator. Furthermore, the use of fluoroscopy in interventional procedures with emphasis on dose reduction to patients and staff is discussed in light of the increasing frequency, complexity and length ofthe procedures. CT is the main reason that medical imaging in several developed countries is the highest annual per capita effective radiation dose from man-made sources. The ICRP report gives extensive descriptions of how CT protocols can be optimized to minimize radiation exposure in pediatric patients. The importance of balancing image quality with acceptable noise in pediatric imaging and the controversies regarding the use of protective shielding in CT are also discussed.

  7. Radiological Control Manual

    International Nuclear Information System (INIS)

    1993-04-01

    This manual has been prepared by Lawrence Berkeley Laboratory to provide guidance for site-specific additions, supplements, and clarifications to the DOE Radiological Control Manual. The guidance provided in this manual is based on the requirements given in Title 10 Code of Federal Regulations Part 835, Radiation Protection for Occupational Workers, DOE Order 5480.11, Radiation Protection for Occupational Workers, and the DOE Radiological Control Manual. The topics covered are (1) excellence in radiological control, (2) radiological standards, (3) conduct of radiological work, (4) radioactive materials, (5) radiological health support operations, (6) training and qualification, and (7) radiological records

  8. Radiological Control Manual

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    This manual has been prepared by Lawrence Berkeley Laboratory to provide guidance for site-specific additions, supplements, and clarifications to the DOE Radiological Control Manual. The guidance provided in this manual is based on the requirements given in Title 10 Code of Federal Regulations Part 835, Radiation Protection for Occupational Workers, DOE Order 5480.11, Radiation Protection for Occupational Workers, and the DOE Radiological Control Manual. The topics covered are (1) excellence in radiological control, (2) radiological standards, (3) conduct of radiological work, (4) radioactive materials, (5) radiological health support operations, (6) training and qualification, and (7) radiological records.

  9. Mastering Uncertainty and Risk at Multiple Time Scales in the Future Electrical Grid

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Laboratory; Bent, Russell W. [Los Alamos National Laboratory; Backhaus, Scott N. [Los Alamos National Laboratory

    2012-07-10

    Today's electrical grids enjoy a relatively clean separation of spatio-temporal scales yielding a compartmentalization of grid design, optimization, control and risk assessment allowing for the use of conventional mathematical tools within each area. In contrast, the future grid will incorporate time-intermittent renewable generation, operate via faster electrical markets, and tap the latent control capability at finer grid modeling scales; creating a fundamentally new set of couplings across spatiotemporal scales and requiring revolutionary advances in mathematics techniques to bridge these scales. One example is found in decade-scale grid expansion planning in which today's algorithms assume accurate load forecasts and well-controlled generation. Incorporating intermittent renewable generation creates fluctuating network flows at the hourly time scale, inherently linking the ability of a transmission line to deliver electrical power to hourly operational decisions. New operations-based planning algorithms are required, creating new mathematical challenges. Spatio-temporal scales are also crossed when the future grid's minute-scale fluctuations in network flows (due to intermittent generation) create a disordered state upon which second-scale transient grid dynamics propagate effectively invalidating today's on-line dynamic stability analyses. Addressing this challenge requires new on-line algorithms that use large data streams from new grid sensing technologies to physically aggregate across many spatial scales to create responsive, data-driven dynamic models. Here, we sketch the mathematical foundations of these problems and potential solutions.

  10. Ambulatory phlebectomy at radiologic outpatient clinic

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Chang Jin; Kang, Sung Gwon; Choi, Sang Il [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Lee, Whal; Chung, Jin Wook; Park, Jae Hyung [Seoul National University, Medical College, Seoul (Korea, Republic of)

    2007-03-15

    To evaluate safety, efficacy, and patient's satisfaction of an ambulatory phlebectomy, performed at a radiology outpatient clinic. Between 2003 and 2006, an ambulatory phlebectomy was performed in 12 patients. Endovenous radiofrequency ablation was performed through a venotomy. The venotomy was ligated after RF ablation, and the ambulatory phlebectomy was performed. The patients visited the radiology outpatient clinic one day, one week, and 2 months after the procedure. The improvement in the clinical symptoms, cosmetic change in varicosity, and the procedure related complications were evaluated. The patient's satisfaction was evaluated using a 5-grade scale. RF ablation through a venotomy was performed successfully in all 12 patients. On average, 4.5 incisions were made, and 12.5 cm of varicosity had been removed. The mean procedure time was one hour and forty minutes. The complications of the ambulatory phlebectomy were bruising in one patient, and skin pigmentation in another. The complications associated with RF ablation were a hard palpable vein in 7 patients, numbness in 7 patients, and skin pigmentation along the vein in 2 patients. Follow-up duplex sonography was performed at 2 months after the procedure, showed complete occlusion in all 12 patients. The clinical symptoms had improved in 11 patients, and the varicosity disappeared cosmetically in 11 patients. An ambulatory phlebectomy, combined with RF ablation of the greater saphenous vein, can be performed safely and effectively at a radiology outpatient clinic.

  11. Ambulatory phlebectomy at radiologic outpatient clinic

    International Nuclear Information System (INIS)

    Yoon, Chang Jin; Kang, Sung Gwon; Choi, Sang Il; Lee, Whal; Chung, Jin Wook; Park, Jae Hyung

    2007-01-01

    To evaluate safety, efficacy, and patient's satisfaction of an ambulatory phlebectomy, performed at a radiology outpatient clinic. Between 2003 and 2006, an ambulatory phlebectomy was performed in 12 patients. Endovenous radiofrequency ablation was performed through a venotomy. The venotomy was ligated after RF ablation, and the ambulatory phlebectomy was performed. The patients visited the radiology outpatient clinic one day, one week, and 2 months after the procedure. The improvement in the clinical symptoms, cosmetic change in varicosity, and the procedure related complications were evaluated. The patient's satisfaction was evaluated using a 5-grade scale. RF ablation through a venotomy was performed successfully in all 12 patients. On average, 4.5 incisions were made, and 12.5 cm of varicosity had been removed. The mean procedure time was one hour and forty minutes. The complications of the ambulatory phlebectomy were bruising in one patient, and skin pigmentation in another. The complications associated with RF ablation were a hard palpable vein in 7 patients, numbness in 7 patients, and skin pigmentation along the vein in 2 patients. Follow-up duplex sonography was performed at 2 months after the procedure, showed complete occlusion in all 12 patients. The clinical symptoms had improved in 11 patients, and the varicosity disappeared cosmetically in 11 patients. An ambulatory phlebectomy, combined with RF ablation of the greater saphenous vein, can be performed safely and effectively at a radiology outpatient clinic

  12. Principles of 5D modeling, full integration of 3D space, time and scale

    NARCIS (Netherlands)

    Van Oosterom, P.; Stoter, J.

    2012-01-01

    This paper proposes an approach for data modelling in five dimensions. Apart from three dimensions for geometrical representation and a fourth dimension for time, we identify scale as fifth dimensional characteristic. Considering scale as an extra dimension of geographic information, fully

  13. Glottal closure instant and voice source analysis using time-scale ...

    Indian Academy of Sciences (India)

    Time-scale analysis entertains close relationships with auditory perception. According to the tonotopic organisation of the inner ear, the first stages of auditory perception can be modelled using a non-uniform filterbank. These auditory filters are organized according to some sort of psychological scale, such as third-octave, ...

  14. Time scales of porphyry Cu deposit formation: insights from titanium diffusion in quartz

    Science.gov (United States)

    Mercer, Celestine N.; Reed, Mark H.; Mercer, Cameron M.

    2015-01-01

    Porphyry dikes and hydrothermal veins from the porphyry Cu-Mo deposit at Butte, Montana, contain multiple generations of quartz that are distinct in scanning electron microscope-cathodoluminescence (SEM-CL) images and in Ti concentrations. A comparison of microprobe trace element profiles and maps to SEM-CL images shows that the concentration of Ti in quartz correlates positively with CL brightness but Al, K, and Fe do not. After calibrating CL brightness in relation to Ti concentration, we use the brightness gradient between different quartz generations as a proxy for Ti gradients that we model to determine time scales of quartz formation and cooling. Model results indicate that time scales of porphyry magma residence are ~1,000s of years and time scales from porphyry quartz phenocryst rim formation to porphyry dike injection and cooling are ~10s of years. Time scales for the formation and cooling of various generations of hydrothermal vein quartz range from 10s to 10,000s of years. These time scales are considerably shorter than the ~0.6 m.y. overall time frame for each porphyry-style mineralization pulse determined from isotopic studies at Butte, Montana. Simple heat conduction models provide a temporal reference point to compare chemical diffusion time scales, and we find that they support short dike and vein formation time scales. We interpret these relatively short time scales to indicate that the Butte porphyry deposit formed by short-lived episodes of hydrofracturing, dike injection, and vein formation, each with discrete thermal pulses, which repeated over the ~3 m.y. generation of the deposit.

  15. Bridging time scales in cellular decision making with a stochastic bistable switch

    Directory of Open Access Journals (Sweden)

    Waldherr Steffen

    2010-08-01

    Full Text Available Abstract Background Cellular transformations which involve a significant phenotypical change of the cell's state use bistable biochemical switches as underlying decision systems. Some of these transformations act over a very long time scale on the cell population level, up to the entire lifespan of the organism. Results In this work, we aim at linking cellular decisions taking place on a time scale of years to decades with the biochemical dynamics in signal transduction and gene regulation, occuring on a time scale of minutes to hours. We show that a stochastic bistable switch forms a viable biochemical mechanism to implement decision processes on long time scales. As a case study, the mechanism is applied to model the initiation of follicle growth in mammalian ovaries, where the physiological time scale of follicle pool depletion is on the order of the organism's lifespan. We construct a simple mathematical model for this process based on experimental evidence for the involved genetic mechanisms. Conclusions Despite the underlying stochasticity, the proposed mechanism turns out to yield reliable behavior in large populations of cells subject to the considered decision process. Our model explains how the physiological time constant may emerge from the intrinsic stochasticity of the underlying gene regulatory network. Apart from ovarian follicles, the proposed mechanism may also be of relevance for other physiological systems where cells take binary decisions over a long time scale.

  16. Insights from inside the spinodal: Bridging thermalization time scales with smoothed particle hydrodynamics

    Science.gov (United States)

    Pütz, Martin; Nielaba, Peter

    2016-08-01

    We report the influence of the strength of heat bath coupling on the demixing behavior in spinodal decomposing one component liquid-vapor systems. The smoothed particle hydrodynamics (SPH) method with a van der Waals equation of state is used for the simulation. A thermostat for SPH is introduced that is based on the Berendsen thermostat. It controls the strength of heat bath coupling and allows for quenches with exponential temperature decay at a certain thermalization time scale. The present method allows us to bridge several orders of magnitude in the thermalization time scale. The early stage is highly affected by the choice of time scale. A transition from exponential growth to a 1 /2 ordinary power law scaling in the characteristic lengths is observed. At high initial temperatures the growth is logarithmic. The comparison with pure thermal simulations reveals latent heat to raise the mean system temperature. Large thermalization time scales and thermal conductivity are figured out to affect a stagnation of heating, which is explained with convective processes. Furthermore, large thermalization time scales are responsible for a stagnation of growth of domains, which is temporally embedded between early and late stage of phase separation. Therefore, it is considered as an intermediate stage. We present an aspect concerning this stage, namely that choosing larger thermalization time scales increases the duration. Moreover, it is observed that diffuse interfaces are formed during this stage, provided that the stage is apparent. We show that the differences in the evolution between pure thermal simulations and simulations with an instantaneously scaled mean temperature can be explained by the thermalization process, since a variation of the time scale allows for the bridging between these cases of limit.

  17. Radiological and geophysical changes around the Fukushima Daiichi Nuclear Power Plant since the accident to the present time

    Science.gov (United States)

    Kolotkov, Gennady

    2013-04-01

    Detailed analysis of accidental released of radioactive material from Fukushima Daiichi nuclear power plant has shown that long-lived radionuclides add considerable support for intensity of ion formation. Based on the results of airborne monitoring by MEXT and DOE (total surface deposition of Cs134 and Cs137 inside 80 km zone of Fukushima Daiichi NPP) it has been calculated the spatial distribution of the intensity of ion formation and atmospheric electric conductivity. The evidence of plutonium in the Fukushima radioactive trace allows calculates the concentration of small, intermediate and large ions. The results show the excess of these parameters by several orders of magnitude since the accident to the present time. For example the concentration of small air ion in the area of Chernobyl is 7±2?102 cm-3, the Fukushima Daiichi NPP ones is 1.3?106 cm-3. The difference in the atmospheric bipolar electric conductivity is about 24 fS/m between the Chernobyl and the Fukushima Daiichi ones. The evaluation technique was used after Chernobyl disaster allows to make an analysis of ecological, hygiene requirements and other problems into the troposphere and on the soil intensity of ion formation in the area of Fukushima Daiichi nuclear power plant. The standard ion air differ by four orders of magnitude in the case for Fukushima Daiichi ones. Comparative study of the radiophysical characteristics of the atmosphere with the analogous ones in Chernobyl and application of identification of various types of the air pollution is discussed.

  18. Time-scale invariances in preseismic electromagnetic radiation, magnetization and damage evolution of rocks

    Directory of Open Access Journals (Sweden)

    Y. Kawada

    2007-10-01

    Full Text Available We investigate the time-scale invariant changes in electromagnetic and mechanical energy releases prior to a rock failure or a large earthquake. The energy release processes are caused by damage evolutions such as crack propagation, motion of charged dislocation, area-enlargement of sheared asperities and repetitive creep-rate changes. Damage mechanics can be used to represent the time-scale invariant evolutions of both brittle and plastic damages. Irreversible thermodynamics applied to the damage mechanics reveals that the damage evolution produces the variations in charge, dipole and electromagnetic signals in addition to mechanical energy release, and yields the time-scale invariant patterns of Benioff electromagnetic radiation and cumulative Benioff strain-release. The irreversible thermodynamic framework of damage mechanics is also applicable to the seismo-magnetic effect, and the time-scale invariance is recognized in the remanent magnetization change associated with damage evolution prior to a rock failure.

  19. Multiple time scale analysis of pressure oscillations in solid rocket motors

    Science.gov (United States)

    Ahmed, Waqas; Maqsood, Adnan; Riaz, Rizwan

    2018-03-01

    In this study, acoustic pressure oscillations for single and coupled longitudinal acoustic modes in Solid Rocket Motor (SRM) are investigated using Multiple Time Scales (MTS) method. Two independent time scales are introduced. The oscillations occur on fast time scale whereas the amplitude and phase changes on slow time scale. Hopf bifurcation is employed to investigate the properties of the solution. The supercritical bifurcation phenomenon is observed for linearly unstable system. The amplitude of the oscillations result from equal energy gain and loss rates of longitudinal acoustic modes. The effect of linear instability and frequency of longitudinal modes on amplitude and phase of oscillations are determined for both single and coupled modes. For both cases, the maximum amplitude of oscillations decreases with the frequency of acoustic mode and linear instability of SRM. The comparison of analytical MTS results and numerical simulations demonstrate an excellent agreement.

  20. Multiple time scales in modeling the incidence of infections acquired in intensive care units

    Directory of Open Access Journals (Sweden)

    Martin Wolkewitz

    2016-09-01

    Full Text Available Abstract Background When patients are admitted to an intensive care unit (ICU their risk of getting an infection will be highly depend on the length of stay at-risk in the ICU. In addition, risk of infection is likely to vary over calendar time as a result of fluctuations in the prevalence of the pathogen on the ward. Hence risk of infection is expected to depend on two time scales (time in ICU and calendar time as well as competing events (discharge or death and their spatial location. The purpose of this paper is to develop and apply appropriate statistical models for the risk of ICU-acquired infection accounting for multiple time scales, competing risks and the spatial clustering of the data. Methods A multi-center data base from a Spanish surveillance network was used to study the occurrence of an infection due to Methicillin-resistant Staphylococcus aureus (MRSA. The analysis included 84,843 patient admissions between January 2006 and December 2011 from 81 ICUs. Stratified Cox models were used to study multiple time scales while accounting for spatial clustering of the data (patients within ICUs and for death or discharge as competing events for MRSA infection. Results Both time scales, time in ICU and calendar time, are highly associated with the MRSA hazard rate and cumulative risk. When using only one basic time scale, the interpretation and magnitude of several patient-individual risk factors differed. Risk factors concerning the severity of illness were more pronounced when using only calendar time. These differences disappeared when using both time scales simultaneously. Conclusions The time-dependent dynamics of infections is complex and should be studied with models allowing for multiple time scales. For patient individual risk-factors we recommend stratified Cox regression models for competing events with ICU time as the basic time scale and calendar time as a covariate. The inclusion of calendar time and stratification by ICU

  1. Integrative teaching in Radiology. A survey

    International Nuclear Information System (INIS)

    Dettmer, S.; Weidemann, J.; Wacker, F.; Fischer, V.

    2015-01-01

    To survey integrative teaching in radiology at German universities. A questionnaire about radiological education was sent electronically to all 37 chairpersons of university radiology departments in Germany. The questions included the course type, teaching methods, concept, perception, and advantages and disadvantages of integrative teaching. Statistical analysis was performed with nonparametric statistics and chi-square test. The survey was considered representative with a return rate of 68%. Integrative teaching is established at 4/5 of all departments. Integrative teaching is well accepted with an acceptance rate that is significantly higher in so-called 'Modellstudiengaengen' (model courses of study) (100%) compared to conventional courses of study (72%). The advantages of integrative teaching include linking of content (92%) and preparation for interdisciplinary work (76%). The disadvantages include high effort (75%) and time (67%) for organization. Furthermore, there is a risk that basic radiological facts and knowledge cannot be conveyed and that the visibility of radiology as an independent discipline is lost. Conventional radiological teaching has a similarly high acceptance (84%) compared to integrative courses (76%). Integrative teaching has a high acceptance among chairpersons in radiology in Germany despite the greater effort. A good interdisciplinary collaboration is essential for integrative teaching and at the same time this can be conveyed to the students. However, the visibility of radiology as a discipline and the possibility to cover basic radiological content must be ensured. Therefore, both conventional courses and integrative teaching seems reasonable, especially in cross-disciplinary subjects such as radiology.

  2. Finite-Time and -Size Scalings in the Evaluation of Large Deviation Functions. Numerical Analysis in Continuous Time

    Science.gov (United States)

    Guevara Hidalgo, Esteban; Nemoto, Takahiro; Lecomte, Vivien

    Rare trajectories of stochastic systems are important to understand because of their potential impact. However, their properties are by definition difficult to sample directly. Population dynamics provide a numerical tool allowing their study, by means of simulating a large number of copies of the system, which are subjected to a selection rule that favors the rare trajectories of interest. However, such algorithms are plagued by finite simulation time- and finite population size- effects that can render their use delicate. Using the continuous-time cloning algorithm, we analyze the finite-time and finite-size scalings of estimators of the large deviation functions associated to the distribution of the rare trajectories. We use these scalings in order to propose a numerical approach which allows to extract the infinite-time and infinite-size limit of these estimators.

  3. Informatics in radiology: RADTF: a semantic search-enabled, natural language processor-generated radiology teaching file.

    Science.gov (United States)

    Do, Bao H; Wu, Andrew; Biswal, Sandip; Kamaya, Aya; Rubin, Daniel L

    2010-11-01

    Storing and retrieving radiology cases is an important activity for education and clinical research, but this process can be time-consuming. In the process of structuring reports and images into organized teaching files, incidental pathologic conditions not pertinent to the primary teaching point can be omitted, as when a user saves images of an aortic dissection case but disregards the incidental osteoid osteoma. An alternate strategy for identifying teaching cases is text search of reports in radiology information systems (RIS), but retrieved reports are unstructured, teaching-related content is not highlighted, and patient identifying information is not removed. Furthermore, searching unstructured reports requires sophisticated retrieval methods to achieve useful results. An open-source, RadLex(®)-compatible teaching file solution called RADTF, which uses natural language processing (NLP) methods to process radiology reports, was developed to create a searchable teaching resource from the RIS and the picture archiving and communication system (PACS). The NLP system extracts and de-identifies teaching-relevant statements from full reports to generate a stand-alone database, thus converting existing RIS archives into an on-demand source of teaching material. Using RADTF, the authors generated a semantic search-enabled, Web-based radiology archive containing over 700,000 cases with millions of images. RADTF combines a compact representation of the teaching-relevant content in radiology reports and a versatile search engine with the scale of the entire RIS-PACS collection of case material. ©RSNA, 2010

  4. Deep Learning in Radiology.

    Science.gov (United States)

    McBee, Morgan P; Awan, Omer A; Colucci, Andrew T; Ghobadi, Comeron W; Kadom, Nadja; Kansagra, Akash P; Tridandapani, Srini; Auffermann, William F

    2018-03-29

    As radiology is inherently a data-driven specialty, it is especially conducive to utilizing data processing techniques. One such technique, deep learning (DL), has become a remarkably powerful tool for image processing in recent years. In this work, the Association of University Radiologists Radiology Research Alliance Task Force on Deep Learning provides an overview of DL for the radiologist. This article aims to present an overview of DL in a manner that is understandable to radiologists; to examine past, present, and future applications; as well as to evaluate how radiologists may benefit from this remarkable new tool. We describe several areas within radiology in which DL techniques are having the most significant impact: lesion or disease detection, classification, quantification, and segmentation. The legal and ethical hurdles to implementation are also discussed. By taking advantage of this powerful tool, radiologists can become increasingly more accurate in their interpretations with fewer errors and spend more time to focus on patient care. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  5. Bounds of Double Integral Dynamic Inequalities in Two Independent Variables on Time Scales

    Directory of Open Access Journals (Sweden)

    S. H. Saker

    2011-01-01

    Full Text Available Our aim in this paper is to establish some explicit bounds of the unknown function in a certain class of nonlinear dynamic inequalities in two independent variables on time scales which are unbounded above. These on the one hand generalize and on the other hand furnish a handy tool for the study of qualitative as well as quantitative properties of solutions of partial dynamic equations on time scales. Some examples are considered to demonstrate the applications of the results.

  6. Time Scale Inequalities of the Ostrowski Type for Functions Differentiable on the Coordinates

    Directory of Open Access Journals (Sweden)

    Eze R. Nwaeze

    2018-01-01

    Full Text Available In 2016, some inequalities of the Ostrowski type for functions (of two variables differentiable on the coordinates were established. In this paper, we extend these results to an arbitrary time scale by means of a parameter λ∈0,1. The aforementioned results are regained for the case when the time scale T=R. Besides extension, our results are employed to the continuous and discrete calculus to get some new inequalities in this direction.

  7. Expanding the functionality of speech recognition in radiology: creating a real-time methodology for measurement and analysis of occupational stress and fatigue.

    Science.gov (United States)

    Reiner, Bruce I

    2013-02-01

    While occupational stress and fatigue have been well described throughout medicine, the radiology community is particularly susceptible due to declining reimbursements, heightened demands for service deliverables, and increasing exam volume and complexity. The resulting occupational stress can be variable in nature and dependent upon a number of intrinsic and extrinsic stressors. Intrinsic stressors largely account for inter-radiologist stress variability and relate to unique attributes of the radiologist such as personality, emotional state, education/training, and experience. Extrinsic stressors may account for intra-radiologist stress variability and include cumulative workload and task complexity. The creation of personalized stress profiles creates a mechanism for accounting for both inter- and intra-radiologist stress variability, which is essential in creating customizable stress intervention strategies. One viable option for real-time occupational stress measurement is voice stress analysis, which can be directly implemented through existing speech recognition technology and has been proven to be effective in stress measurement and analysis outside of medicine. This technology operates by detecting stress in the acoustic properties of speech through a number of different variables including duration, glottis source factors, pitch distribution, spectral structure, and intensity. The correlation of these speech derived stress measures with outcomes data can be used to determine the user-specific inflection point at which stress becomes detrimental to clinical performance.

  8. Radiological Evaluation Standards in the Radiology Department of Shahid Beheshti Hospital (RAH) YASUJ Based on Radiology standards in 92

    OpenAIRE

    A َKalantari; SAM Khosravani

    2014-01-01

    Background & aim: Radiology personnel’s working in terms of performance and safety is one of the most important functions in order to increase the quality and quantity. This study aimed to evaluate the radiological standards in Shahid Beheshti Hospital of Yasuj, Iran, in 2013. Methods: The present cross-sectional study was based on a 118 randomly selected graphs and the ranking list, with full knowledge of the standards in radiology was performed two times. Data were analyzed using descri...

  9. Training in radiological protection

    International Nuclear Information System (INIS)

    Medina G, E.

    2014-08-01

    In the Peru, according to the current regulations, people that work with ionizing radiations should have an authorization (individual license), which is granted by the Technical Office of the National Authority that is the technical body of the Instituto Peruano de Energia Nuclear (IPEN) manager of the control of ionizing radiations in the country. The individual license is obtained after the applicant fulfills the requested requirements, as having safety knowledge and radiological protection. Since its founding in 1972, the Centro Superior de Estudios Nucleares (CSEN) of the IPEN has carried out diverse training courses in order to that people can work in a safe way with ionizing radiations in medicine, industry and research, until the year 2013 have been organized 2231 courses that have allowed the training of 26213 people. The courses are organized according to the specific work that is carried out with radiations (medical radio-diagnostic, dental radiology, nuclear medicine, radiotherapy, industrial radiography, nuclear meters, logging while drilling, etc.). In their majority the courses are directed to people that will make use of radiations for first time, but refresher courses are also granted in the topic. The CSEN also carries out the Master degree programs highlighting the Second Professional Specialization in Radiological Protection carried out from the year 2004 with the support of the National University of Engineering. To the present has been carried out 2 programs and there is other being developed. In this work is shown the historical evolution of the radiological protection courses as well as the important thing that they are to work in a safe way in the country. (Author)

  10. Technical Report on the 6th Time Scale Algorithm Symposium and Tutorials

    Science.gov (United States)

    2016-03-29

    registered people, including 4 students , coming from more than 30 different countries participated to the 3 days of conference. The Tutorials (the...Algorithms for the international time scales UTC and UTCr, Dr. Panfilo, BIPM 11:30-11:50 Tea/ coffee break 11:50-12:35 National Time Scales, Dr...NRL 16:00-16:20 Tea/ Coffee Break 16:20-17:05 Algorithms for GNSS Time Transfer, Dr. Defraigne, ORB 17:05-17:50 Algorithms to support time

  11. Impact of sequential disorder on the scaling behavior of airplane boarding time

    Science.gov (United States)

    Baek, Yongjoo; Ha, Meesoon; Jeong, Hawoong

    2013-05-01

    Airplane boarding process is an example where disorder properties of the system are relevant to the emergence of universality classes. Based on a simple model, we present a systematic analysis of finite-size effects in boarding time, and propose a comprehensive view of the role of sequential disorder in the scaling behavior of boarding time against the plane size. Using numerical simulations and mathematical arguments, we find how the scaling behavior depends on the number of seat columns and the range of sequential disorder. Our results show that new scaling exponents can arise as disorder is localized to varying extents.

  12. The role of topography on catchment‐scale water residence time

    Science.gov (United States)

    McGuire, K.J.; McDonnell, Jeffery J.; Weiler, M.; Kendall, C.; McGlynn, B.L.; Welker, J.M.; Seibert, J.

    2005-01-01

    The age, or residence time, of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways, and source of water in a single integrated measure. While there has been tremendous recent interest in residence time estimation to characterize watersheds, there are relatively few studies that have quantified residence time at the watershed scale, and fewer still that have extended those results beyond single catchments to larger landscape scales. We examined topographic controls on residence time for seven catchments (0.085–62.4 km2) that represent diverse geologic and geomorphic conditions in the western Cascade Mountains of Oregon. Our primary objective was to determine the dominant physical controls on catchment‐scale water residence time and specifically test the hypothesis that residence time is related to the size of the basin. Residence times were estimated by simple convolution models that described the transfer of precipitation isotopic composition to the stream network. We found that base flow mean residence times for exponential distributions ranged from 0.8 to 3.3 years. Mean residence time showed no correlation to basin area (r2 organization (i.e., topography) rather than basin area controls catchment‐scale transport. Results from this study may provide a framework for describing scale‐invariant transport across climatic and geologic conditions, whereby the internal form and structure of the basin defines the first‐order control on base flow residence time.

  13. A hybrid procedure for MSW generation forecasting at multiple time scales in Xiamen City, China

    International Nuclear Information System (INIS)

    Xu, Lilai; Gao, Peiqing; Cui, Shenghui; Liu, Chun

    2013-01-01

    Highlights: ► We propose a hybrid model that combines seasonal SARIMA model and grey system theory. ► The model is robust at multiple time scales with the anticipated accuracy. ► At month-scale, the SARIMA model shows good representation for monthly MSW generation. ► At medium-term time scale, grey relational analysis could yield the MSW generation. ► At long-term time scale, GM (1, 1) provides a basic scenario of MSW generation. - Abstract: Accurate forecasting of municipal solid waste (MSW) generation is crucial and fundamental for the planning, operation and optimization of any MSW management system. Comprehensive information on waste generation for month-scale, medium-term and long-term time scales is especially needed, considering the necessity of MSW management upgrade facing many developing countries. Several existing models are available but of little use in forecasting MSW generation at multiple time scales. The goal of this study is to propose a hybrid model that combines the seasonal autoregressive integrated moving average (SARIMA) model and grey system theory to forecast MSW generation at multiple time scales without needing to consider other variables such as demographics and socioeconomic factors. To demonstrate its applicability, a case study of Xiamen City, China was performed. Results show that the model is robust enough to fit and forecast seasonal and annual dynamics of MSW generation at month-scale, medium- and long-term time scales with the desired accuracy. In the month-scale, MSW generation in Xiamen City will peak at 132.2 thousand tonnes in July 2015 – 1.5 times the volume in July 2010. In the medium term, annual MSW generation will increase to 1518.1 thousand tonnes by 2015 at an average growth rate of 10%. In the long term, a large volume of MSW will be output annually and will increase to 2486.3 thousand tonnes by 2020 – 2.5 times the value for 2010. The hybrid model proposed in this paper can enable decision makers to

  14. Radiological field survey problems and solutions

    International Nuclear Information System (INIS)

    Deming, E.J.; Boerner, A.J.

    1986-01-01

    Situations often arise during radiological field surveys which require the health physicist to improvise and/or make spot decisions. At times these situations can be humorous, but they can also present hazards more serious than normal radiological considerations. This presentation will depict various problematic situations encountered by Oak Ridge Associated Universities Radiological Site Assessment Program in the course of performing field environmental surveys. Detailing these potential hazards can alert other field survey groups to problems they may encounter

  15. Double Scaling in the Relaxation Time in the β -Fermi-Pasta-Ulam-Tsingou Model

    Science.gov (United States)

    Lvov, Yuri V.; Onorato, Miguel

    2018-04-01

    We consider the original β -Fermi-Pasta-Ulam-Tsingou system; numerical simulations and theoretical arguments suggest that, for a finite number of masses, a statistical equilibrium state is reached independently of the initial energy of the system. Using ensemble averages over initial conditions characterized by different Fourier random phases, we numerically estimate the time scale of equipartition and we find that for very small nonlinearity it matches the prediction based on exact wave-wave resonant interaction theory. We derive a simple formula for the nonlinear frequency broadening and show that when the phenomenon of overlap of frequencies takes place, a different scaling for the thermalization time scale is observed. Our result supports the idea that the Chirikov overlap criterion identifies a transition region between two different relaxation time scalings.

  16. Validating a rapid-update satellite precipitation analysis across telescoping space and time scales

    Science.gov (United States)

    Turk, Francis Joseph; Sohn, Byung-Ju; Oh, Hyun-Jong; Ebert, Elizabeth E.; Levizzani, Vincenzo; Smith, Eric A.

    2009-09-01

    In order to properly utilize remotely sensed precipitation estimates in hydrometeorological applications, knowledge of the accuracy of the estimates are needed. However, relatively few ground validation networks operate with the necessary spatial density and time-resolution required for validation of high-resolution precipitation products (HRPP) generated at fine space and time scales (e.g., hourly accumulations produced on a 0.25° spatial scale). In this article, we examine over-land validation statistics for an operationally designed, meteorological satellite-based global rainfall analysis that blends intermittent passive microwave-derived rainfall estimates aboard a variety of low Earth-orbiting satellite platforms with sub-hourly time sampling capabilities of visible and infrared imagers aboard operational geostationary platforms. The validation dataset is comprised of raingauge data collected from the dense, nearly homogeneous, 1-min reporting Automated Weather Station (network of the Korean Meteorological Administration during the June to August 2000 summer monsoon season. The space-time RMS error, mean bias, and correlation matrices were computed using various time windows for the gauge averaging, centered about the satellite observation time. For ±10 min time window, a correlation of 0.6 was achieved at 0.1° spatial scale by averaging more than 3 days; coarsening the spatial scale to 1.8° produced the same correlation by averaging over 1 h. Finer than approximately 24-h and 1° time and space scales, respectively, a rapid decay of the error statistics was obtained by trading-off either spatial or time resolution. Beyond a daily time scale, the blended estimates were nearly unbiased and with an RMS error of no worse than 1 mm day-1.

  17. Weighing Scale-Based Pulse Transit Time is a Superior Marker of Blood Pressure than Conventional Pulse Arrival Time

    Science.gov (United States)

    Martin, Stephanie L.-O.; Carek, Andrew M.; Kim, Chang-Sei; Ashouri, Hazar; Inan, Omer T.; Hahn, Jin-Oh; Mukkamala, Ramakrishna

    2016-12-01

    Pulse transit time (PTT) is being widely pursued for cuff-less blood pressure (BP) monitoring. Most efforts have employed the time delay between ECG and finger photoplethysmography (PPG) waveforms as a convenient surrogate of PTT. However, these conventional pulse arrival time (PAT) measurements include the pre-ejection period (PEP) and the time delay through small, muscular arteries and may thus be an unreliable marker of BP. We assessed a bathroom weighing scale-like system for convenient measurement of ballistocardiography and foot PPG waveforms - and thus PTT through larger, more elastic arteries - in terms of its ability to improve tracking of BP in individual subjects. We measured “scale PTT”, conventional PAT, and cuff BP in humans during interventions that increased BP but changed PEP and smooth muscle contraction differently. Scale PTT tracked the diastolic BP changes well, with correlation coefficient of -0.80 ± 0.02 (mean ± SE) and root-mean-squared-error of 7.6 ± 0.5 mmHg after a best-case calibration. Conventional PAT was significantly inferior in tracking these changes, with correlation coefficient of -0.60 ± 0.04 and root-mean-squared-error of 14.6 ± 1.5 mmHg (p < 0.05). Scale PTT also tracked the systolic BP changes better than conventional PAT but not to an acceptable level. With further development, scale PTT may permit reliable, convenient measurement of BP.

  18. Studying time of flight imaging through scattering media across multiple size scales (Conference Presentation)

    Science.gov (United States)

    Velten, Andreas

    2017-05-01

    Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.

  19. Overcoming time scale and finite size limitations to compute nucleation rates from small scale well tempered metadynamics simulations

    Science.gov (United States)

    Salvalaglio, Matteo; Tiwary, Pratyush; Maggioni, Giovanni Maria; Mazzotti, Marco; Parrinello, Michele

    2016-12-01

    Condensation of a liquid droplet from a supersaturated vapour phase is initiated by a prototypical nucleation event. As such it is challenging to compute its rate from atomistic molecular dynamics simulations. In fact at realistic supersaturation conditions condensation occurs on time scales that far exceed what can be reached with conventional molecular dynamics methods. Another known problem in this context is the distortion of the free energy profile associated to nucleation due to the small, finite size of typical simulation boxes. In this work the problem of time scale is addressed with a recently developed enhanced sampling method while contextually correcting for finite size effects. We demonstrate our approach by studying the condensation of argon, and showing that characteristic nucleation times of the order of magnitude of hours can be reliably calculated. Nucleation rates spanning a range of 10 orders of magnitude are computed at moderate supersaturation levels, thus bridging the gap between what standard molecular dynamics simulations can do and real physical systems.

  20. Educational treasures in Radiology: The Radiology Olympics - striving for gold in Radiology education

    OpenAIRE

    Talanow, Roland

    2010-01-01

    This article focuses on Radiology Olympics (www.RadiologyOlympics.com) - a collaboration with the international Radiology community for Radiology education, Radiolopolis (www.Radiolopolis.com). The Radiology Olympics honour the movers and shakers in Radiology education and offer an easy to use platform for educating medical professionals based on Radiology cases.

  1. Mixing and flushing time scales in the Azhikode Estuary, southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Revichandran, C.; Pylee, A.

    Flushing time scales of the Azhikode Estuary, Kerala, India showed pronounced dry season and wet season signals as well as large inter-annual variation. Cumulative flushing time of the estuary varies from 4.8 tide cycles in April to 1.22 tide cycles...

  2. Modulation of SST, SSS over northern Bay of Bengal on ISO time scale

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, S.A.; Saha, S.K.; Pokhrel, S.; Sundar, D.; Dhakate, A.R.; Mahapatra, S.; Ali, S.; Chaudhari, H.S.; Shreeram, P.; Suneel, V.; Srikanth, A.S.; Suresh, R.R.V.

    hypothesize that the intra-seasonal rainfall variation modulates the amount of river discharge, which in turn modulates the salinity over northern Bay of Bengal on intra-seasonal time scale. Since surface warming always follows the surface freshening, the time...

  3. Time Scale Analysis of Interest Rate Spreads and Output Using Wavelets

    Directory of Open Access Journals (Sweden)

    Marco Gallegati

    2013-04-01

    Full Text Available This paper adds to the literature on the information content of different spreads for real activity by explicitly taking into account the time scale relationship between a variety of monetary and financial indicators (real interest rate, term and credit spreads and output growth. By means of wavelet-based exploratory data analysis we obtain richer results relative to the aggregate analysis by identifying the dominant scales of variation in the data and the scales and location at which structural breaks have occurred. Moreover, using the “double residuals” regression analysis on a scale-by-scale basis, we find that changes in the spread in several markets have different information content for output at different time frames. This is consistent with the idea that allowing for different time scales of variation in the data can provide a fruitful understanding of the complex dynamics of economic relationships between variables with non-stationary or transient components, certainly richer than those obtained using standard time domain methods.

  4. Dynamics of Bayesian non-Gaussian sensorimotor learning with multiple time scales

    Science.gov (United States)

    Zhou, Baohua; Hofmann, David; Sober, Samuel; Nemenman, Ilya

    Various theoretical and experimental studies have suggested that sensorimotor learning in animals happens on multiple time scales. In such models, animals can respond to perturbations quickly but keep memories for a long period of time. However, those previous models only focus on average learning behaviors. Here, we propose a model with multiple time scales that deals with the dynamics of whole behavior distributions. The model includes multiple memories, each with a non-Gaussian distribution and its own associated time scale. The memories are combined to generate a distribution of the desired motor command. Our model explains simultaneously the dynamics of distributions of the songbird vocal behaviors in various experiments, including adaptations after step changes or ramps in the error signals and dynamics of forgetting during the washout period, where an immediate sharp approach to the baseline is followed by a prolonged decay. This work was supported partially by NIH Grant # 1 R01 EB022872, and NIH Grant # NS084844.

  5. Laenderyggens degeneration og radiologi

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Gosvig, Kasper Kjaerulf; Sonne-Holm, Stig

    2006-01-01

    Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP and signi...... is cyclic: exacerbations relieved by asymptomatic periods. New imaging modalities, including the combination of MR imaging and multiplanar 3-D CT scans, have broadened our awareness of possible pain-generating degenerative processes of the lumbar spine other than disc degeneration....

  6. Acute Radiological Abnormalities after Bronchial Thermoplasty: A Prospective Cohort Trial

    NARCIS (Netherlands)

    d'Hooghe, Julia N. S.; van den Berk, Inge A. H.; Annema, Jouke T.; Bonta, Peter I.

    2017-01-01

    Background: Bronchial thermoplasty (BT) is a novel treatment for severe asthma based on radiofrequency energy delivery to the larger airways. Although impressive radiological abnormalities have been reported, the incidence, pattern, and behavior over time of acute radiological abnormalities

  7. Wavelet-Based Multi-Scale Entropy Analysis of Complex Rainfall Time Series

    Directory of Open Access Journals (Sweden)

    Chien-Ming Chou

    2011-01-01

    Full Text Available This paper presents a novel framework to determine the number of resolution levels in the application of a wavelet transformation to a rainfall time series. The rainfall time series are decomposed using the à trous wavelet transform. Then, multi-scale entropy (MSE analysis that helps to elucidate some hidden characteristics of the original rainfall time series is applied to the decomposed rainfall time series. The analysis shows that the Mann-Kendall (MK rank correlation test of MSE curves of residuals at various resolution levels could determine the number of resolution levels in the wavelet decomposition. The complexity of rainfall time series at four stations on a multi-scale is compared. The results reveal that the suggested number of resolution levels can be obtained using MSE analysis and MK test. The complexity of rainfall time series at various locations can also be analyzed to provide a reference for water resource planning and application.

  8. Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period

    DEFF Research Database (Denmark)

    Blunier, T; Brook, E J

    2001-01-01

    A precise relative chronology for Greenland and West Antarctic paleotemperature is extended to 90,000 years ago, based on correlation of atmospheric methane records from the Greenland Ice Sheet Project 2 and Byrd ice cores. Over this period, the onset of seven major millennial-scale warmings in A....... This pattern provides further evidence for the operation of a "bipolar see-saw" in air temperatures and an oceanic teleconnection between the hemispheres on millennial time scales....

  9. Evaluating scaled windowed variance methods for estimating the Hurst coefficient of time series

    OpenAIRE

    Cannon, Michael J.; Percival, Donald B.; Caccia, David C.; Raymond, Gary M.; Bassingthwaighte, James B.

    1997-01-01

    Three-scaled windowed variance methods (standard, linear regression detrended, and brdge detrended) for estimating the Hurst coefficient (H) are evaluated. The Hurst coefficient, with 0 < H < 1, characterizes self-similar decay in the time-series autocorrelation function. The scaled windowed variance methods estimate H for fractional Brownian motion (fBm) signals which are cumulative sums of fractional Gaussian noise (fGn) signals. For all three methods both the bias and standard deviation of...

  10. An alcator-like confinement time scaling law derived from buckingham's PI theorem

    International Nuclear Information System (INIS)

    Roth, J.R.

    1983-01-01

    The unsatisfactory state of understanding of particle transport and confinement in tokamaks is well known. The best available theory, neoclassical transport, predicts a confinement time which scales as the square of the magnetic field, and inversely as the number density. Until recently, the best available phenomenological scaling law was the Alcator scaling law. This scaling law has recently been supplanted by the neoAlcator scaling law. Both of these expressions are unsatisfactory, because they not only are unsupported by any physical theory, but also their numerical constants are dimensional, suggesting that additional physical parameters need to be accounted for. A more firmly based scaling law can be derived from Buckingham's pi theorem. We adopt the particle confinement time as the dependent variable (derived dimension), and as independent variables (fundamental dimensions) we use the plasma volume, the average ion charge density, the ion current on the limiter, and the magnetic induction. From Buckingham's pi theorem, we obtain an equation which correctly predicts the absence of magnetic induction dependence, and the direct dependence on the ion density. The dependence on the product of the major radius and the plasma radius is intermediate between the original and neoAlcator scaling laws, and may be consistent with the data if the ion kinetic temperature and limiter area were accounted for

  11. Interventional Radiology: Stroke

    Science.gov (United States)

    ... Government affairs Global outreach Publications Annual Report IR Quarterly Journal of Vascular and Interventional Radiology Newsletters Practice Resources Quality Improvement Clinical practice MACRA Matters Health Policy, Economics, Coding Toolkits Society of Interventional Radiology 3975 Fair ...

  12. Predicting Regional Drought on Sub-Seasonal to Decadal Time Scales

    Science.gov (United States)

    Schubert, Siegfried; Wang, Hailan; Suarez, Max; Koster, Randal

    2011-01-01

    Drought occurs on a wide range of time scales, and within a variety of different types of regional climates. It is driven foremost by an extended period of reduced precipitation, but it is the impacts on such quantities as soil moisture, streamflow and crop yields that are often most important from a users perspective. While recognizing that different users have different needs for drought information, it is nevertheless important to understand that progress in predicting drought and satisfying such user needs, largely hinges on our ability to improve predictions of precipitation. This talk reviews our current understanding of the physical mechanisms that drive precipitation variations on subseasonal to decadal time scales, and the implications for predictability and prediction skill. Examples are given highlighting the phenomena and mechanisms controlling precipitation on monthly (e.g., stationary Rossby waves, soil moisture), seasonal (ENSO) and decadal time scales (PD and AMO).

  13. Radiological diagnostics in hyperparathyroidism

    International Nuclear Information System (INIS)

    Moedder, U.; Kuhn, F.P.; Gruetzner, G.

    1991-01-01

    The most important radiologically detectable effects of the primary and secondary hyperparathyroidism of the skeletal system and the periarticular soft tissue structures are presented. In the following sensitivity and specificity of radiological imaging - sonography, scintigraphy, computed tomography, magnetic resonance imaging, arteriography and selective venous sampling - in the preoperative diagnostic of the parathyroid adenomas are discussed. Therefore, radiological imaging can be omitted before primary surgery. It was only in secondary surgery that radiological process proved useful and a guide during surgical intervention. (orig.) [de

  14. Cavity-Enhanced Real-Time Monitoring of Single-Charge Jumps at the Microsecond Time Scale

    Science.gov (United States)

    Arnold, C.; Loo, V.; Lemaître, A.; Sagnes, I.; Krebs, O.; Voisin, P.; Senellart, P.; Lanco, L.

    2014-04-01

    We use fast coherent reflectivity measurements, in a strongly coupled quantum dot micropillar device, to monitor in real time single-charge jumps at the microsecond time scale. Thanks to the strong enhancement of light-matter interaction inside the cavity, and to a close to shot-noise-limited detection setup, the measurement rate is 5 orders of magnitude faster than with previous optical experiments of direct single-charge sensing with quantum dots. The monitored transitions, identified at any given time with a less than 0.2% error probability, correspond to a carrier being captured and then released by a single material defect. This high-speed technique opens the way for the real-time monitoring of other rapid single quantum events, such as the quantum jumps of a single spin.

  15. Response of vegetation to drought time-scales across global land biomes.

    Science.gov (United States)

    Vicente-Serrano, Sergio M; Gouveia, Célia; Camarero, Jesús Julio; Beguería, Santiago; Trigo, Ricardo; López-Moreno, Juan I; Azorín-Molina, César; Pasho, Edmond; Lorenzo-Lacruz, Jorge; Revuelto, Jesús; Morán-Tejeda, Enrique; Sanchez-Lorenzo, Arturo

    2013-01-02

    We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change.

  16. Computational Fluid Dynamics Study on the Effects of RATO Timing on the Scale Model Acoustic Test

    Science.gov (United States)

    Nielsen, Tanner; Williams, B.; West, Jeff

    2015-01-01

    The Scale Model Acoustic Test (SMAT) is a 5% scale test of the Space Launch System (SLS), which is currently being designed at Marshall Space Flight Center (MSFC). The purpose of this test is to characterize and understand a variety of acoustic phenomena that occur during the early portions of lift off, one being the overpressure environment that develops shortly after booster ignition. The SLS lift off configuration consists of four RS-25 liquid thrusters on the core stage, with two solid boosters connected to each side. Past experience with scale model testing at MSFC (in ER42), has shown that there is a delay in the ignition of the Rocket Assisted Take Off (RATO) motor, which is used as the 5% scale analog of the solid boosters, after the signal to ignite is given. This delay can range from 0 to 16.5ms. While this small of a delay maybe insignificant in the case of the full scale SLS, it can significantly alter the data obtained during the SMAT due to the much smaller geometry. The speed of sound of the air and combustion gas constituents is not scaled, and therefore the SMAT pressure waves propagate at approximately the same speed as occurs during full scale. However, the SMAT geometry is much smaller allowing the pressure waves to move down the exhaust duct, through the trench, and impact the vehicle model much faster than occurs at full scale. To better understand the effect of the RATO timing simultaneity on the SMAT IOP test data, a computational fluid dynamics (CFD) analysis was performed using the Loci/CHEM CFD software program. Five different timing offsets, based on RATO ignition delay statistics, were simulated. A variety of results and comparisons will be given, assessing the overall effect of RATO timing simultaneity on the SMAT overpressure environment.

  17. Radiology systems architecture.

    Science.gov (United States)

    Deibel, S R; Greenes, R A

    1996-05-01

    This article focuses on the software requirements for enterprise integration in radiology. The needs of a future radiology systems architecture are examined, both at a concrete functional level and at an abstract system-properties level. A component-based approach to software development is described and is validated in the context of each of the abstract system requirements for future radiology computing environments.

  18. Rapid-mixing studies on the time-scale of radiation damage in cells

    International Nuclear Information System (INIS)

    Adams, G.E.; Michael, B.D.; Asquith, J.C.; Shenoy, M.A.; Watts, M.E.; Whillans, D.W.

    1975-01-01

    Rapid mixing studies were performed to determine the time scale of radiation damage in cells. There is evidence that the sensitizing effects of oxygen and other chemical dose-modifying agents on the response of cells to ionizing radiation involve fast free-radical processes. Fast response technique studies in bacterial systems have shown that extremely fast processes occur when the bacteria are exposed to oxygen or other dose-modifying agents during irradiation. The time scales observed were consistent with the involvement of fast free-radical reactions in the expression of these effects

  19. New Bounds of Ostrowski–Gruss Type Inequality for (k + 1 Points on Time Scales

    Directory of Open Access Journals (Sweden)

    Eze R. Nwaeze

    2017-11-01

    Full Text Available The aim of this paper is to present three new bounds of the Ostrowski--Gr\\"uss type inequality for points $x_0,x_1,x_2,\\cdots,x_k$ on time scales. Our results generalize result of Ng\\^o and Liu, and extend results of Ujevi\\'c to time scales with $(k+1$ points. We apply our results to the continuous, discrete, and quantum calculus to obtain many new interesting inequalities. An example is also considered. The estimates obtained in this paper will be very useful in numerical integration especially for the continuous case.

  20. Development of radiology in Mongolia

    International Nuclear Information System (INIS)

    Gonchigsuren, D.; Munkhbaatar, D.; Tuvshinjargal, D.; Onkhuudai, P.

    2007-01-01

    Full text: Radiology had been introduced in Mongolia by the establishment of the first X-Ray room at the First State Central Hospital in 1934. First radiologists in Mongolia were invited from the former Soviet Union; V. Sokolov, P. Omelchenko and others worked at the ''Burevestnik'' X-ray equipment of Russian production with high X-ray exposure and low capacity; they could perform only limited arts of Xray studies like fluoroscopy of thorax, stomach, esophagus and roentgenography of skull and extremities. The second X- ray equipment has been presented by the close friend of Lenin, the Director of People's Commissariat of Health Protection of the Soviet Union, Dr. N.A. Semashko; the present had been dedicated to the 10th Anniversary of Mongolian Health Care sector. During the military maneuvers at Khalkhin- Gol in 1939, several province hospitals and military hospitals had been supplied by the Xray equipment. During the period 1959-1960 all province hospitals, specialized hospitals had got X-ray unit. In 1955, Radii 226 had been used at first time in Mongolia for a treatment. In 1959, the State Radiological Clinic had been founded as a branch of X-ray cabinet of the First State Central Hospital. By the initiative of the absolvent of University of Leipzig, German Democratic Republic, Dr. P. Onkhuudai, Laboratory of Nuclear Medicine was established on 31 PstP March 1975 at the First State Central Hospital, which performed urography, thyroid and liver studies using Iod-131, Au-198, Hg-203 isotopes. In 1982, the gamma-camera and radio immunological equipment had been donated by the World Health Organization, and the Laboratory of Nuclear Medicine had been reorganized into Department of Nuclear Laboratory. Afterwards, in 1992 CT and SPECT diagnostics had been introduced at the First State Central Hospital, therefore new possibilities for high quality radiological diagnostic in Mongolia had been created. In 2007 the Siemens Magnetom 0.3 Tesla had been installed at the

  1. Radiological Protection Science and Application

    International Nuclear Information System (INIS)

    Janssens, Augustin; ); Mossman, Ken; Morgan, Bill

    2016-01-01

    Since the discovery of radiation at the end of the 19. century, the health effects of exposure to radiation have been studied more than almost any other factor with potential effects on human health. The NEA has long been involved in discussions on the effects of radiation exposure, releasing two reports in 1994 and 2007 on radiological protection science. This report is the third in this state-of-the-art series, examining recent advances in the understanding of radiation risks and effects, particularly at low doses. It focuses on radiobiology and epidemiology, and also addresses the social science aspects of stakeholder involvement in radiological protection decision making. The report summarises the status of, and issues arising from, the application of the International System of Radiological Protection to different types of prevailing circumstances. Reports published by the NEA Committee on Radiation Protection and Public Health (CRPPH) in 1998 and 2007 provided an overview of the scientific knowledge available at that time, as well as the expected results from further research. They also discussed the policy implications that these results could have for the radiological protection system. The 2007 report highlighted challenges posed by developments in relation to medical exposure and by intentions to include the environment (i.e. non-human species), within the scope of the radiological protection system. It also addressed the need to be able to respond to a radiological terrorist attack. This report picks up on where the 1998 and 2007 reports left off, and addresses the state of the art in radiological prevention science and application today. It is divided into five chapters. Firstly, following broadly the structural topics from the 1998 and 2007 reports, the more purely scientific aspects of radiological protection are presented. These include cancer risk of low dose and dose rates, non-cancer effects and individual sensitivity. In view of the increasing

  2. Integrative teaching in radiology - a survey.

    Science.gov (United States)

    Dettmer, S; Weidemann, J; Fischer, V; Wacker, F K

    2015-04-01

    To survey integrative teaching in radiology at German universities. A questionnaire about radiological education was sent electronically to all 37 chairpersons of university radiology departments in Germany. The questions included the course type, teaching methods, concept, perception, and advantages and disadvantages of integrative teaching. Statistical analysis was performed with nonparametric statistics and chi-square test. The survey was considered representative with a return rate of 68 %. Integrative teaching is established at 4/5 of all departments. Integrative teaching is well accepted with an acceptance rate that is significantly higher in so-called "Modellstudiengängen" [model courses of study] (100 %) compared to conventional courses of study (72 %). The advantages of integrative teaching include linking of content (92 %) and preparation for interdisciplinary work (76 %). The disadvantages include high effort (75 %) and time (67 %) for organization. Furthermore, there is a risk that basic radiological facts and knowledge cannot be conveyed and that the visibility of radiology as an independent discipline is lost. Conventional radiological teaching has a similarly high acceptance (84 %) compared to integrative courses (76 %). Integrative teaching has a high acceptance among chairpersons in radiology in Germany despite the greater effort. A good interdisciplinary collaboration is essential for integrative teaching and at the same time this can be conveyed to the students. However, the visibility of radiology as a discipline and the possibility to cover basic radiological content must be ensured. Therefore, both conventional courses and integrative teaching seems reasonable, especially in cross-disciplinary subjects such as radiology. Both integrative teaching and conventional radiological teaching are highly accepted. The advantages include the linking of multidisciplinary content and the preparation for interdisciplinary cooperation

  3. Time-sliced perturbation theory for large scale structure I: general formalism

    Energy Technology Data Exchange (ETDEWEB)

    Blas, Diego; Garny, Mathias; Sibiryakov, Sergey [Theory Division, CERN, CH-1211 Genève 23 (Switzerland); Ivanov, Mikhail M., E-mail: diego.blas@cern.ch, E-mail: mathias.garny@cern.ch, E-mail: mikhail.ivanov@cern.ch, E-mail: sergey.sibiryakov@cern.ch [FSB/ITP/LPPC, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland)

    2016-07-01

    We present a new analytic approach to describe large scale structure formation in the mildly non-linear regime. The central object of the method is the time-dependent probability distribution function generating correlators of the cosmological observables at a given moment of time. Expanding the distribution function around the Gaussian weight we formulate a perturbative technique to calculate non-linear corrections to cosmological correlators, similar to the diagrammatic expansion in a three-dimensional Euclidean quantum field theory, with time playing the role of an external parameter. For the physically relevant case of cold dark matter in an Einstein-de Sitter universe, the time evolution of the distribution function can be found exactly and is encapsulated by a time-dependent coupling constant controlling the perturbative expansion. We show that all building blocks of the expansion are free from spurious infrared enhanced contributions that plague the standard cosmological perturbation theory. This paves the way towards the systematic resummation of infrared effects in large scale structure formation. We also argue that the approach proposed here provides a natural framework to account for the influence of short-scale dynamics on larger scales along the lines of effective field theory.

  4. Implementation of a Radiological Safety Coach program

    International Nuclear Information System (INIS)

    Konzen, K.K.

    1998-01-01

    The Safe Sites of Colorado Radiological Safety program has implemented a Safety Coach position, responsible for mentoring workers and line management by providing effective on-the-job radiological skills training and explanation of the rational for radiological safety requirements. This position is significantly different from a traditional classroom instructor or a facility health physicist, and provides workers with a level of radiological safety guidance not routinely provided by typical training programs. Implementation of this position presents a challenge in providing effective instruction, requiring rapport with the radiological worker not typically developed in the routine radiological training environment. The value of this unique training is discussed in perspective with cost-savings through better radiological control. Measures of success were developed to quantify program performance and providing a realistic picture of the benefits of providing one-on-one or small group training. This paper provides a description of the unique features of the program, measures of success for the program, a formula for implementing this program at other facilities, and a strong argument for the success (or failure) of the program in a time of increased radiological safety emphasis and reduced radiological safety budgets

  5. Implementation of a Radiological Safety Coach program

    Energy Technology Data Exchange (ETDEWEB)

    Konzen, K.K. [Safe Sites of Colorado, Golden, CO (United States). Rocky Flats Environmental Technology Site; Langsted, J.M. [M.H. Chew and Associates, Golden, CO (United States)

    1998-02-01

    The Safe Sites of Colorado Radiological Safety program has implemented a Safety Coach position, responsible for mentoring workers and line management by providing effective on-the-job radiological skills training and explanation of the rational for radiological safety requirements. This position is significantly different from a traditional classroom instructor or a facility health physicist, and provides workers with a level of radiological safety guidance not routinely provided by typical training programs. Implementation of this position presents a challenge in providing effective instruction, requiring rapport with the radiological worker not typically developed in the routine radiological training environment. The value of this unique training is discussed in perspective with cost-savings through better radiological control. Measures of success were developed to quantify program performance and providing a realistic picture of the benefits of providing one-on-one or small group training. This paper provides a description of the unique features of the program, measures of success for the program, a formula for implementing this program at other facilities, and a strong argument for the success (or failure) of the program in a time of increased radiological safety emphasis and reduced radiological safety budgets.

  6. Radiology research in mainland China in the past 10 years: a survey of original articles published in Radiology and European Radiology.

    Science.gov (United States)

    Zhang, Long Jiang; Wang, Yun Fei; Yang, Zhen Lu; Schoepf, U Joseph; Xu, Jiaqian; Lu, Guang Ming; Li, Enzhong

    2017-10-01

    To evaluate the features and trends of Radiology research in Mainland China through bibliometric analysis of the original articles published in Radiology and European Radiology (ER) between 2006 and 2015. We reviewed the original articles published in Radiology and ER between 2006 and 2015. The following information was abstracted: imaging subspecialty, imaging technique(s) used, research type, sample size, study design, statistical analysis, study results, funding declarations, international collaborations, number of authors, department and province of the first author. All variables were examined longitudinally over time. Radiology research in Mainland China saw a substantial increase in original research articles published, especially in the last 5 years (P articles published in Radiology and ER. Radiology research in Mainland China has seen substantial growth in the past 5 years with neuroradiology, vascular/interventional Radiology, and abdominal Radiology as the most productive fields. MR imaging is the most used modality. Article provenience shows a distinct geographical pattern. • Radiology research in Mainland China saw a substantial increase. • Neuroradiology, vascular/interventional Radiology, and abdominal Radiology are the most productive fields. • MRI is the most used modality in Mainland China's Radiology research. • Guangdong, Shanghai, and Beijing are the most productive provinces.

  7. Time-variable gravity potential components for optical clock comparisons and the definition of international time scales

    Science.gov (United States)

    Voigt, C.; Denker, H.; Timmen, L.

    2016-12-01

    The latest generation of optical atomic clocks is approaching the level of one part in 1018 in terms of frequency stability and uncertainty. For clock comparisons and the definition of international time scales, a relativistic redshift effect of the clock frequencies has to be taken into account at a corresponding uncertainty level of about 0.1 m2 s-2 and 0.01 m in terms of gravity potential and height, respectively. Besides the predominant static part of the gravity potential, temporal variations must be considered in order to avoid systematic frequency shifts. Time-variable gravity potential components induced by tides and non-tidal mass redistributions are investigated with regard to the level of one part in 1018. The magnitudes and dominant time periods of the individual gravity potential contributions are investigated globally and for specific laboratory sites together with the related uncertainty estimates. The basics of the computation methods are presented along with the applied models, data sets and software. Solid Earth tides contribute by far the most dominant signal with a global maximum amplitude of 4.2 m2 s-2 for the potential and a range (maximum-to-minimum) of up to 1.3 and 10.0 m2 s-2 in terms of potential differences between specific laboratories over continental and intercontinental scales, respectively. Amplitudes of the ocean tidal loading potential can amount up to 1.25 m2 s-2, while the range of the potential between specific laboratories is 0.3 and 1.1 m2 s-2 over continental and intercontinental scales, respectively. These are the only two contributors being relevant at a 10-17 level. However, several other time-variable potential effects can particularly affect clock comparisons at the 10-18 level. Besides solid Earth pole tides, these are non-tidal mass redistributions in the atmosphere, the oceans and the continental water storage.

  8. Scales

    Science.gov (United States)

    Scales are a visible peeling or flaking of outer skin layers. These layers are called the stratum ... Scales may be caused by dry skin, certain inflammatory skin conditions, or infections. Examples of disorders that ...

  9. Virtual radiology rounds: adding value in the digital era

    Energy Technology Data Exchange (ETDEWEB)

    Fefferman, Nancy R.; Strubel, Naomi A.; Prithiani, Chandan; Chakravarti, Sujata; Caprio, Martha; Recht, Michael P. [New York University School of Medicine, Department of Radiology, New York, NY (United States)

    2016-11-15

    To preserve radiology rounds in the changing health care environment, we have introduced virtual radiology rounds, an initiative enabling clinicians to remotely review imaging studies with the radiologist. We describe our initial experience with virtual radiology rounds and referring provider impressions. Virtual radiology rounds, a web-based conference, use remote sharing of radiology workstations. Participants discuss imaging studies by speakerphone. Virtual radiology rounds were piloted with the Neonatal Intensive Care Unit (NICU) and the Congenital Cardiovascular Care Unit (CCVCU). Providers completed a survey assessing the perceived impact and overall value of virtual radiology rounds on patient care using a 10-point scale. Pediatric radiologists participating in virtual radiology rounds completed a survey assessing technical, educational and clinical aspects of this methodology. Sixteen providers responded to the survey; 9 NICU and 7 CCVCU staff (physicians, nurse practitioners and fellows). Virtual radiology rounds occurred 4-5 sessions/week with an average of 6.4 studies. Clinicians rated confidence in their own image interpretation with a 7.4 average rating for NICU and 7.5 average rating for CCVCU. Clinicians unanimously rated virtual radiology rounds as adding value. NICU staff preferred virtual radiology rounds to traditional rounds and CCVCU staff supported their new participation in virtual radiology rounds. Four of the five pediatric radiologists participating in virtual radiology rounds responded to the survey reporting virtual radiology rounds to be easy to facilitate (average rating: 9.3), to moderately impact interpretation of imaging studies (average rating: 6), and to provide substantial educational value for radiologists (average rating: 8.3). All pediatric radiologists felt strongly that virtual radiology rounds enable increased integration of the radiologist into the clinical care team (average rating: 8.8). Virtual radiology rounds are a

  10. Volatility Clustering and Scaling for Financial Time Series due to Attractor Bubbling

    Science.gov (United States)

    Krawiecki, A.; Hołyst, J. A.; Helbing, D.

    2002-09-01

    A microscopic model of financial markets is considered, consisting of many interacting agents (spins) with global coupling and discrete-time heat bath dynamics, similar to random Ising systems. The interactions between agents change randomly in time. In the thermodynamic limit, the obtained time series of price returns show chaotic bursts resulting from the emergence of attractor bubbling or on-off intermittency, resembling the empirical financial time series with volatility clustering. For a proper choice of the model parameters, the probability distributions of returns exhibit power-law tails with scaling exponents close to the empirical ones.

  11. Time-scale effects on the gain-loss asymmetry in stock indices.

    Science.gov (United States)

    Sándor, Bulcsú; Simonsen, Ingve; Nagy, Bálint Zsolt; Néda, Zoltán

    2016-08-01

    The gain-loss asymmetry, observed in the inverse statistics of stock indices is present for logarithmic return levels that are over 2%, and it is the result of the non-Pearson-type autocorrelations in the index. These non-Pearson-type correlations can be viewed also as functionally dependent daily volatilities, extending for a finite time interval. A generalized time-window shuffling method is used to show the existence of such autocorrelations. Their characteristic time scale proves to be smaller (less than 25 trading days) than what was previously believed. It is also found that this characteristic time scale has decreased with the appearance of program trading in the stock market transactions. Connections with the leverage effect are also established.

  12. Data warehousing technologies for large-scale and right-time data

    DEFF Research Database (Denmark)

    Xiufeng, Liu

    , but big, tables with few columns, the presented triple-store spreads the data over more tables that may have many columns. The triple-store is optimized by an extensive use of bulk techniques, which makes it very efficient to insert and extract data. The DBMS-based solution makes it very flexible......This thesis is about data warehousing technologies for large-scale and right-time data. Today, due to the exponential growth of data, it has become a common practice for many enterprises to process hundreds of gigabytes of data per day. Traditionally, data warehousing populates data from...... heterogeneous sources into a central data warehouse (DW) by Extract-Transform-Load (ETL) at regular time intervals, e.g., monthly, weekly, or daily. But now, it becomes challenging for large-scale data, and hard to meet the near real-time/right-time business decisions. This thesis considers some...

  13. Linking Time and Space Scales in Distributed Hydrological Modelling - a case study for the VIC model

    Science.gov (United States)

    Melsen, Lieke; Teuling, Adriaan; Torfs, Paul; Zappa, Massimiliano; Mizukami, Naoki; Clark, Martyn; Uijlenhoet, Remko

    2015-04-01

    One of the famous paradoxes of the Greek philosopher Zeno of Elea (~450 BC) is the one with the arrow: If one shoots an arrow, and cuts its motion into such small time steps that at every step the arrow is standing still, the arrow is motionless, because a concatenation of non-moving parts does not create motion. Nowadays, this reasoning can be refuted easily, because we know that motion is a change in space over time, which thus by definition depends on both time and space. If one disregards time by cutting it into infinite small steps, motion is also excluded. This example shows that time and space are linked and therefore hard to evaluate separately. As hydrologists we want to understand and predict the motion of water, which means we have to look both in space and in time. In hydrological models we can account for space by using spatially explicit models. With increasing computational power and increased data availability from e.g. satellites, it has become easier to apply models at a higher spatial resolution. Increasing the resolution of hydrological models is also labelled as one of the 'Grand Challenges' in hydrology by Wood et al. (2011) and Bierkens et al. (2014), who call for global modelling at hyperresolution (~1 km and smaller). A literature survey on 242 peer-viewed articles in which the Variable Infiltration Capacity (VIC) model was used, showed that the spatial resolution at which the model is applied has decreased over the past 17 years: From 0.5 to 2 degrees when the model was just developed, to 1/8 and even 1/32 degree nowadays. On the other hand the literature survey showed that the time step at which the model is calibrated and/or validated remained the same over the last 17 years; mainly daily or monthly. Klemeš (1983) stresses the fact that space and time scales are connected, and therefore downscaling the spatial scale would also imply downscaling of the temporal scale. Is it worth the effort of downscaling your model from 1 degree to 1

  14. Time-scale effects on the gain-loss asymmetry in stock indices

    Science.gov (United States)

    Sándor, Bulcsú; Simonsen, Ingve; Nagy, Bálint Zsolt; Néda, Zoltán

    2016-08-01

    The gain-loss asymmetry, observed in the inverse statistics of stock indices is present for logarithmic return levels that are over 2 % , and it is the result of the non-Pearson-type autocorrelations in the index. These non-Pearson-type correlations can be viewed also as functionally dependent daily volatilities, extending for a finite time interval. A generalized time-window shuffling method is used to show the existence of such autocorrelations. Their characteristic time scale proves to be smaller (less than 25 trading days) than what was previously believed. It is also found that this characteristic time scale has decreased with the appearance of program trading in the stock market transactions. Connections with the leverage effect are also established.

  15. Implications of cosmic strings with time-varying tension on the CMB and large scale structure

    International Nuclear Information System (INIS)

    Ichikawa, Kazuhide; Takahashi, Tomo; Yamaguchi, Masahide

    2006-01-01

    We investigate cosmological evolution and implications of cosmic strings with time-dependent tension. We derive basic equations of time development of the correlation length and the velocity of such strings, based on the one-scale model. Then, we find that, in the case where the tension depends on some power of the cosmic time, cosmic strings with time-dependent tension goes into the scaling solution if the power is lower than a critical value. We also discuss cosmic microwave background anisotropy and matter power spectra produced by these strings. The constraints on their tensions from the Wilkinson microwave anisotropy probe (WMAP) 3 yr data and Sloan digital sky survey (SDSS) data are also given

  16. Scaling relation between earthquake magnitude and the departure time from P wave similar growth

    Science.gov (United States)

    Noda, Shunta; Ellsworth, William L.

    2016-01-01

    We introduce a new scaling relation between earthquake magnitude (M) and a characteristic of initial P wave displacement. By examining Japanese K-NET data averaged in bins partitioned by Mw and hypocentral distance, we demonstrate that the P wave displacement briefly displays similar growth at the onset of rupture and that the departure time (Tdp), which is defined as the time of departure from similarity of the absolute displacement after applying a band-pass filter, correlates with the final M in a range of 4.5 ≤ Mw ≤ 7. The scaling relation between Mw and Tdp implies that useful information on the final M can be derived while the event is still in progress because Tdp occurs before the completion of rupture. We conclude that the scaling relation is important not only for earthquake early warning but also for the source physics of earthquakes.

  17. A Systematic Multi-Time Scale Solution for Regional Power Grid Operation

    Science.gov (United States)

    Zhu, W. J.; Liu, Z. G.; Cheng, T.; Hu, B. Q.; Liu, X. Z.; Zhou, Y. F.

    2017-10-01

    Many aspects need to be taken into consideration in a regional grid while making schedule plans. In this paper, a systematic multi-time scale solution for regional power grid operation considering large scale renewable energy integration and Ultra High Voltage (UHV) power transmission is proposed. In the time scale aspect, we discuss the problem from month, week, day-ahead, within-day to day-behind, and the system also contains multiple generator types including thermal units, hydro-plants, wind turbines and pumped storage stations. The 9 subsystems of the scheduling system are described, and their functions and relationships are elaborated. The proposed system has been constructed in a provincial power grid in Central China, and the operation results further verified the effectiveness of the system.

  18. Spatiotemporal patterns of drought at various time scales in Shandong Province of Eastern China

    Science.gov (United States)

    Zuo, Depeng; Cai, Siyang; Xu, Zongxue; Li, Fulin; Sun, Wenchao; Yang, Xiaojing; Kan, Guangyuan; Liu, Pin

    2018-01-01

    The temporal variations and spatial patterns of drought in Shandong Province of Eastern China were investigated by calculating the standardized precipitation evapotranspiration index (SPEI) at 1-, 3-, 6-, 12-, and 24-month time scales. Monthly precipitation and air temperature time series during the period 1960-2012 were collected at 23 meteorological stations uniformly distributed over the region. The non-parametric Mann-Kendall test was used to explore the temporal trends of precipitation, air temperature, and the SPEI drought index. S-mode principal component analysis (PCA) was applied to identify the spatial patterns of drought. The results showed that an insignificant decreasing trend in annual total precipitation was detected at most stations, a significant increase of annual average air temperature occurred at all the 23 stations, and a significant decreasing trend in the SPEI was mainly detected at the coastal stations for all the time scales. The frequency of occurrence of extreme and severe drought at different time scales generally increased with decades; higher frequency and larger affected area of extreme and severe droughts occurred as the time scale increased, especially for the northwest of Shandong Province and Jiaodong peninsular. The spatial pattern of drought for SPEI-1 contains three regions: eastern Jiaodong Peninsular and northwestern and southern Shandong. As the time scale increased to 3, 6, and 12 months, the order of the three regions was transformed into another as northwestern Shandong, eastern Jiaodong Peninsular, and southern Shandong. For SPEI-24, the location identified by REOF1 was slightly shifted from northwestern Shandong to western Shandong, and REOF2 and REOF3 identified another two weak patterns in the south edge and north edge of Jiaodong Peninsular, respectively. The potential causes of drought and the impact of drought on agriculture in the study area have also been discussed. The temporal variations and spatial patterns

  19. On the spot ethical decision-making in CBRN (chemical, biological, radiological or nuclear event) response: approaches to on the spot ethical decision-making for first responders to large-scale chemical incidents.

    Science.gov (United States)

    Rebera, Andrew P; Rafalowski, Chaim

    2014-09-01

    First responders to chemical, biological, radiological, or nuclear (CBRN) events face decisions having significant human consequences. Some operational decisions are supported by standard operating procedures, yet these may not suffice for ethical decisions. Responders will be forced to weigh their options, factoring-in contextual peculiarities; they will require guidance on how they can approach novel (indeed unique) ethical problems: they need strategies for "on the spot" ethical decision making. The primary aim of this paper is to examine how first responders should approach on the spot ethical decision-making amid the stress and uncertainty of a CBRN event. Drawing on the long-term professional CBRN experience of one of the authors, this paper sets out a series of practical ethical dilemmas potentially arising in the context of a large-scale chemical incident. We propose a broadly consequentialist approach to on the spot ethical decision-making, but one which incorporates ethical values and rights as "side-constraints".

  20. First-passage times in multiscale random walks: The impact of movement scales on search efficiency

    Science.gov (United States)

    Campos, Daniel; Bartumeus, Frederic; Raposo, E. P.; Méndez, Vicenç

    2015-11-01

    An efficient searcher needs to balance properly the trade-off between the exploration of new spatial areas and the exploitation of nearby resources, an idea which is at the core of scale-free Lévy search strategies. Here we study multiscale random walks as an approximation to the scale-free case and derive the exact expressions for their mean-first-passage times in a one-dimensional finite domain. This allows us to provide a complete analytical description of the dynamics driving the situation in which both nearby and faraway targets are available to the searcher, so the exploration-exploitation trade-off does not have a trivial solution. For this situation, we prove that the combination of only two movement scales is able to outperform both ballistic and Lévy strategies. This two-scale strategy involves an optimal discrimination between the nearby and faraway targets which is only possible by adjusting the range of values of the two movement scales to the typical distances between encounters. So, this optimization necessarily requires some prior information (albeit crude) about target distances or distributions. Furthermore, we found that the incorporation of additional (three, four, …) movement scales and its adjustment to target distances does not improve further the search efficiency. This allows us to claim that optimal random search strategies arise through the informed combination of only two walk scales (related to the exploitative and the explorative scales, respectively), expanding on the well-known result that optimal strategies in strictly uninformed scenarios are achieved through Lévy paths (or, equivalently, through a hierarchical combination of multiple scales).

  1. Radiological protection report 2012

    International Nuclear Information System (INIS)

    2013-06-01

    measurements. In addition, the Swiss Federal Office of Public Health publishes environmental monitoring data in its Annual Report. For the purpose of monitoring environmental radioactivity, ENSI operates a network that automatically monitors dose rates in the vicinity of nuclear power plants. The results are made available to the Swiss National Emergency Operations Centre, the Ministry of the Environment in Baden-Wuerttemberg and the European Radiological Data Exchange Platform. In 2012 emissions from Swiss nuclear facilities are similar to those in previous years and in the immediate vicinity of nuclear facilities the annual dose is less than 10μSv. However, the water-borne releases of radiation from the Muehleberg nuclear power station, unlike those at other nuclear facilities, continue to be so high that further remedial measures are required. In the field of dispersion, hourly simulations are calculated for all locations in the vicinity of a nuclear power station. They are based on current 3D wind speeds as provided by MeteoSwiss with a spatial resolution of 2 km. These calculations, together with the annual aero-radiometric test flights, are a valuable and precise tool that can be used at any time to analyse the current situation and forecast the development of radiation

  2. Sensitivity of the breastfeeding motivational measurement scale: a known group analysis of first time mothers.

    Science.gov (United States)

    Stockdale, Janine; Sinclair, Marlene; Kernohan, George; McCrum-Gardner, Evie; Keller, John

    2013-01-01

    Breastfeeding has immense public health value for mothers, babies, and society. But there is an undesirably large gap between the number of new mothers who undertake and persist in breastfeeding compared to what would be a preferred level of accomplishment. This gap is a reflection of the many obstacles, both physical and psychological, that confront new mothers. Previous research has illuminated many of these concerns, but research on this problem is limited in part by the unavailability of a research instrument that can measure the key differences between first-time mothers and experienced mothers, with regard to the challenges they face when breastfeeding and the instructional advice they require. An instrument was designed to measure motivational complexity associated with sustained breast feeding behaviour; the Breastfeeding Motivational Measurement Scale. It contains 51 self-report items (7 point Likert scale) that cluster into four categories related to perceived value of breast-feeding, confidence to succeed, factors that influence success or failure, and strength of intentions, or goal. However, this scale has not been validated in terms of its sensitivity to profile the motivation of new mothers and experienced mothers. This issue was investigated by having 202 breastfeeding mothers (100 first time mothers) fill out the scale. The analysis reported in this paper is a three factor solution consisting of value, midwife support, and expectancies for success that explained the characteristics of first time mothers as a known group. These results support the validity of the BMM scale as a diagnostic tool for research on first time mothers who are learning to breastfeed. Further research studies are required to further test the validity of the scale in additional subgroups.

  3. Towards a Unified Formulation of Dynamics and Thermodynamics I. From Microscopic to Macroscopic Time Scales

    Czech Academy of Sciences Publication Activity Database

    Durand, P.; Paidarová, Ivana

    2011-01-01

    Roč. 111, č. 2 (2011), s. 225-236 ISSN 0020-7608 R&D Projects: GA AV ČR IAA100400501; GA AV ČR IAA401870702 Institutional research plan: CEZ:AV0Z40400503 Keywords : Liouville equation * time scales * chemical kinetics and dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.357, year: 2011

  4. Fission time-scale from the measurement of pre-scission light ...

    Indian Academy of Sciences (India)

    Fission time-scale from pre-scission light particles and γ-ray multiplicities. Figure 1. Schematic representation of the experimental set-up (see text). light particle detectors used along with the data analysis can be found in [1]. In sum- mary, after the energy and efficiency calibration of the neutron spectra from NE213 liquid.

  5. Anti-control of chaos of single time-scale brushless DC motor.

    Science.gov (United States)

    Ge, Zheng-Ming; Chang, Ching-Ming; Chen, Yen-Sheng

    2006-09-15

    Anti-control of chaos of single time-scale brushless DC motors is studied in this paper. In order to analyse a variety of periodic and chaotic phenomena, we employ several numerical techniques such as phase portraits, bifurcation diagrams and Lyapunov exponents. Anti-control of chaos can be achieved by adding an external constant term or an external periodic term.

  6. Hardy inequality on time scales and its application to half-linear dynamic equations

    Directory of Open Access Journals (Sweden)

    Řehák Pavel

    2005-01-01

    Full Text Available A time-scale version of the Hardy inequality is presented, which unifies and extends well-known Hardy inequalities in the continuous and in the discrete setting. An application in the oscillation theory of half-linear dynamic equations is given.

  7. Principal and nonprincipal solutions of symplectic dynamic systems on time scales

    Directory of Open Access Journals (Sweden)

    Ondrej Dosly

    2000-01-01

    Full Text Available We establish the concept of the principal and nonprincipal solution for the so-called symplectic dynamic systems on time scales. We also present a brief survey of the history of these concept for differential and difference equations.

  8. Labour productivity, economies of scale and opening time in large retail establishments

    NARCIS (Netherlands)

    A.R. Thurik (Roy)

    1984-01-01

    textabstractDifferences in labour productivity are dealt with for large French retail establishments. Influences of scale, weekly opening time, assortment composition, wage rate and share of counter service are considered. The relationship used is a result of analyses in the field of small retail

  9. A singular perturbation theorem for evolution equations and time-scale arguments for structured population models

    NARCIS (Netherlands)

    Greiner, G.; Heesterbeek, J.A.P.; Metz, J.A.J.

    1994-01-01

    In this paper we present a generalization of a finite dimensional singular perturbation theorem to Banach spaces. From this we obtain sufficient conditions under which a faithful simplification by a time-scale argument is justified for age-structured models of slowly growing populations. An explicit

  10. A Visual Method of Time Scale Determination using a PC for Radio ...

    Indian Academy of Sciences (India)

    not easy to fit the light curve. In this paper, we proposed a method of light curve fitting on a PC machine, in which the theoretical exponential light curve is adopted to the observations using the least regression method. Using this method, anybody can fit the light curve and get the time scale by moving and clicking the mouse.

  11. Development and Preliminary Validation of the Time Management for Exercise Scale

    Science.gov (United States)

    Hellsten, Laurie-ann M.; Rogers, W. Todd

    2009-01-01

    The purpose of this study was to collect preliminary validity evidence for a time management scale for exercise. An initial pool of 91 items was developed from existing literature. Ten exercise/health psychologists evaluated each of the items in terms of relevance and representativeness. Forty-nine items met all criteria. Exploratory factor…

  12. Global Stability of Complex-Valued Genetic Regulatory Networks with Delays on Time Scales

    Directory of Open Access Journals (Sweden)

    Wang Yajing

    2016-01-01

    Full Text Available In this paper, the global exponential stability of complex-valued genetic regulatory networks with delays is investigated. Besides presenting conditions guaranteeing the existence of a unique equilibrium pattern, its global exponential stability is discussed. Some numerical examples for different time scales.

  13. A limit set trichotomy for order-preserving systems on time scales

    Directory of Open Access Journals (Sweden)

    Christian Poetzsche

    2004-04-01

    Full Text Available In this paper we derive a limit set trichotomy for abstract order-preserving 2-parameter semiflows in normal cones of strongly ordered Banach spaces. Additionally, to provide an example, Muller's theorem is generalized to dynamic equations on arbitrary time scales and applied to a model from population dynamics.

  14. Improving Building Performance at Urban Scale with a Framework for Real-time Data Sharing

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Xiufeng; Hong, Tianzhen; Piette, Mary Ann

    2013-06-03

    This paper describes work in progress toward an urban-scale system aiming to reduce energy use in neighboring buildings by providing three components: a database for accessing past and present weather data from high quality weather stations; a network for communicating energy-saving strategies between building owners; and a set of modeling tools for real-time building energy simulation.

  15. Time-scale effects in the interaction between a large and a small herbivore

    NARCIS (Netherlands)

    Kuijper, D.P.J.; Beek, P.; Wieren, van S.E.; Bakker, J.P.

    2008-01-01

    In the short term, grazing will mainly affect plant biomass and forage quality. However, grazing can affect plant species composition by accelerating or retarding succession at longer time-scales. Few studies concerning interactions among herbivores have taken the change in plant species composition

  16. Arctic energy budget in relation to sea ice variability on monthly-to-annual time scales

    NARCIS (Netherlands)

    Krikken, F.; Hazeleger, W.

    2015-01-01

    The large decrease in Arctic sea ice in recent years has triggered a strong interest in Arctic sea ice predictions on seasonal-to-decadal time scales. Hence, it is important to understand physical processes that provide enhanced predictability beyond persistence of sea ice anomalies. This study

  17. Oscillation and nonoscillation for impulsive dynamic equations on certain time scales

    Directory of Open Access Journals (Sweden)

    Henderson Johnny

    2006-01-01

    Full Text Available We discuss the existence of oscillatory and nonoscillatory solutions for first-order impulsive dynamic equations on time scales with certain restrictions on the points of impulse. We will rely on the nonlinear alternative of Leray-Schauder type combined with a lower and upper solutions method.

  18. Eigenvalue Problems for Systems of Nonlinear Boundary Value Problems on Time Scales

    Directory of Open Access Journals (Sweden)

    Henderson J

    2007-01-01

    Full Text Available Values of λ are determined for which there exist positive solutions of the system of dynamic equations, , , for , satisfying the boundary conditions, , where is a time scale. A Guo-Krasnosel'skii fixed point-theorem is applied.

  19. Theoretical and Numerical Properties of a Gyrokinetic Plasma: Issues Related to Transport Time Scale Simulation

    International Nuclear Information System (INIS)

    Lee, W.W.

    2003-01-01

    Particle simulation has played an important role for the recent investigations on turbulence in magnetically confined plasmas. In this paper, theoretical and numerical properties of a gyrokinetic plasma as well as its relationship with magnetohydrodynamics (MHD) are discussed with the ultimate aim of simulating microturbulence in transport time scale using massively parallel computers

  20. Time scales: from Nabla calculus to Delta calculus and vice versa via duality

    OpenAIRE

    Caputo, M. Cristina

    2009-01-01

    In this note we show how one can obtain results from the nabla calculus from results on the delta calculus and vice versa via a duality argument. We provide applications of the main results to the calculus of variations on time scales.

  1. Quantifying particle dispersal in aquatic sediments at short time scales: model selection

    NARCIS (Netherlands)

    Meysman, F.J.R.; Malyuga, V.; Boudreau, B.P.; Middelburg, J.J.

    2008-01-01

    In a pulse-tracer experiment, a layer of tracer particles is added to the sediment-water interface, and the down-mixing of these particles is followed over a short time scale. Here, we compare different models (biodiffusion, telegraph, CTRW) to analyse the resulting tracer depth profiles. The

  2. Fission time-scale from the measurement of pre-scission light ...

    Indian Academy of Sciences (India)

    which are incorporated in the code JOANNE2 to extract fission time-scales and mean deformation of the saddle-to-scission emitter. The neutron, light charged particle and GDR γ-ray multiplicity data could be explained consistently. The emission of neutrons seems to be favoured towards larger deformation as compared to ...

  3. Time scales for spinodal decomposition in nuclear matter with pseudo-particle model

    International Nuclear Information System (INIS)

    Idier, D.; Benhassine, B.; Farine, M.; Remaud, B.; Sebille, F.

    1993-01-01

    Dynamical instabilities arising from fluctuations in the spinodal zone for nuclear matter are studied using a large variety of zero range interactions in the frame of a pseudo-particle model. Scale times for spinodal decomposition are extracted and a possible link with decomposition in real heavy-ion collisions is discussed. (author) 12 refs.; 6 figs.; 1 tab

  4. Assessment of the methods for determining net radiation at different time-scales of meteorological variables

    Directory of Open Access Journals (Sweden)

    Ni An

    2017-04-01

    Full Text Available When modeling the soil/atmosphere interaction, it is of paramount importance to determine the net radiation flux. There are two common calculation methods for this purpose. Method 1 relies on use of air temperature, while Method 2 relies on use of both air and soil temperatures. Nowadays, there has been no consensus on the application of these two methods. In this study, the half-hourly data of solar radiation recorded at an experimental embankment are used to calculate the net radiation and long-wave radiation at different time-scales (half-hourly, hourly, and daily using the two methods. The results show that, compared with Method 2 which has been widely adopted in agronomical, geotechnical and geo-environmental applications, Method 1 is more feasible for its simplicity and accuracy at shorter time-scale. Moreover, in case of longer time-scale, daily for instance, less variations of net radiation and long-wave radiation are obtained, suggesting that no detailed soil temperature variations can be obtained. In other words, shorter time-scales are preferred in determining net radiation flux.

  5. Extension of the astronomically calibrated (polarity) time scale to the Miocene/Pliocene boundary

    NARCIS (Netherlands)

    Hilgen, F.J.

    1991-01-01

    The early Pleistocene to late Pliocene astronormcally calibrated time scale of Shackleton et al. [1] and Hllgen [2] is extended to the Mlocene/Pllocene boundary This is done by correlating the detailed record of CaCO 3 cycles in the Trubl and the lower part of the overlying Narbone Formation

  6. Radiology and fine art.

    Science.gov (United States)

    Marinković, Slobodan; Stošić-Opinćal, Tatjana; Tomić, Oliver

    2012-07-01

    The radiologic aesthetics of some body parts and internal organs have inspired certain artists to create specific works of art. Our aim was to describe the link between radiology and fine art. We explored 13,625 artworks in the literature produced by 2049 artists and found several thousand photographs in an online image search. The examination revealed 271 radiologic artworks (1.99%) created by 59 artists (2.88%) who mainly applied radiography, sonography, CT, and MRI. Some authors produced radiologic artistic photographs, and others used radiologic images to create artful compositions, specific sculptures, or digital works. Many radiologic artworks have symbolic, metaphoric, or conceptual connotations. Radiology is clearly becoming an original and important field of modern art.

  7. Existence and global exponential stability of periodic solutions for n-dimensional neutral dynamic equations on time scales.

    Science.gov (United States)

    Li, Bing; Li, Yongkun; Zhang, Xuemei

    2016-01-01

    In this paper, by using the existence of the exponential dichotomy of linear dynamic equations on time scales and the theory of calculus on time scales, we study the existence and global exponential stability of periodic solutions for a class of n-dimensional neutral dynamic equations on time scales. We also present an example to illustrate the feasibility of our results. The results of this paper are completely new and complementary to the previously known results even in both the case of differential equations (time scale [Formula: see text]) and the case of difference equations (time scale [Formula: see text]).

  8. Radiological protection report 2010

    International Nuclear Information System (INIS)

    2011-01-01

    This is the 7 th Annual Report of the Swiss Federal Nuclear Safety Inspectorate (ENSI) on radiological protection in Swiss nuclear facilities. Section A deals with doses for staff and individual jobs and Section B covers releases from nuclear facilities and the monitoring of environmental radioactivity in their immediate vicinity. The year under review was again marked by an event classified by ENSI as Level 2 on the INES Scale. During maintenance work in the fuel-assembly transfer system at the Leibstadt nuclear power station, a diver recovered a pipe-like object. The object, which was highly radioactive, was the end piece from a jacketed pipe previously removed from the in-core instrumentation. Subsequent investigations showed that the diver had been exposed to a hand dose of 7.5 Sv and a complete-body dose of 28 mSv, both in excess of the annual limits specified in the Swiss Radiological Protection Ordinance. As with the INES-2 event in 2009, this event showed that particular attention is required when working with high and variable radiation fields. In terms of radiological protection, a range of measures must be introduced as a matter of urgency, including for example, measures to ensure that acoustic alarms and warnings from electronic dosimeters are audible immediately even under difficult working conditions. In addition, there needs to be a systematic identification of radiation fields and this information must be made available to all concerned. Neither collective nor average individual doses have changed significantly in recent years. The average individual dose for personnel in nuclear facilities is now 0.7 mSv. This is significantly lower than both the maximum annual limit for persons exposed to radiation in the course of their work and the average annual rate of exposure to radon for the population in Switzerland as a whole (3.2 mSv). The maximum individual dose in the Leibstadt nuclear power plant was 28 mSv. The maximum dose rate at the Goesgen

  9. Evolution of equilibrium Pickering emulsions--a matter of time scales.

    Science.gov (United States)

    Kraft, Daniela J; Luigjes, Bob; de Folter, Julius W J; Philipse, Albert P; Kegel, Willem K

    2010-09-30

    A new class of equilibrium solid-stabilized oil-in-water emulsions harbors a competition of two processes on disparate time scales that affect the equilibrium droplet size in opposing ways. The aim of this work is to elucidate the molecular origins of these two time scales and demonstrate their effects on the evolution of the emulsion droplet size. First, spontaneous emulsification into particle-covered droplets occurs through in situ generation of surface-active molecules by hydrolysis of molecules of the oil phase. We show that surface tensions of the oil-water interfaces in the absence of stabilizing colloidal particles are connected to the concentration of these surface-active molecules, and hence also to the equilibrium droplet size in the presence of colloids. As a consequence, the hydrolysis process sets the time scale of formation of these solid-stabilized emulsions. A second time scale is governing the ultimate fate of the solid-stabilized equilibrium emulsions: by condensation of the in situ generated amphiphilic molecules onto the colloidal particles, their wetting properties change, leading to a gradual transfer from the aqueous to the oil phase via growth of the emulsion droplets. This migration is observed macroscopically by a color change of the water and oil phases, as well as by electron microscopy after polymerization of the oil phase in a phase separated sample. Surprisingly, the relative oil volume sets the time scale of particle transfer. Phase separation into an aqueous phase and an oil phase containing colloidal particles is influenced by sedimentation of the emulsion droplets. The two processes of formation of surface-active molecules through hydrolysis and condensation thereof on the colloidal surface have an opposite influence on the droplet size. By their interplay, a dynamic equilibrium is created where the droplet size always adjusts to the thermodynamically stable state.

  10. Robust scaling laws for energy confinement time, including radiated fraction, in Tokamaks

    Science.gov (United States)

    Murari, A.; Peluso, E.; Gaudio, P.; Gelfusa, M.

    2017-12-01

    In recent years, the limitations of scalings in power-law form that are obtained from traditional log regression have become increasingly evident in many fields of research. Given the wide gap in operational space between present-day and next-generation devices, robustness of the obtained models in guaranteeing reasonable extrapolability is a major issue. In this paper, a new technique, called symbolic regression, is reviewed, refined, and applied to the ITPA database for extracting scaling laws of the energy-confinement time at different radiated fraction levels. The main advantage of this new methodology is its ability to determine the most appropriate mathematical form of the scaling laws to model the available databases without the restriction of their having to be power laws. In a completely new development, this technique is combined with the concept of geodesic distance on Gaussian manifolds so as to take into account the error bars in the measurements and provide more reliable models. Robust scaling laws, including radiated fractions as regressor, have been found; they are not in power-law form, and are significantly better than the traditional scalings. These scaling laws, including radiated fractions, extrapolate quite differently to ITER, and therefore they require serious consideration. On the other hand, given the limitations of the existing databases, dedicated experimental investigations will have to be carried out to fully understand the impact of radiated fractions on the confinement in metallic machines and in the next generation of devices.

  11. The Chapman psychosis-proneness scales: Consistency across culture and time.

    Science.gov (United States)

    Chan, Raymond C K; Shi, Hai-song; Geng, Fu-lei; Liu, Wen-hua; Yan, Chao; Wang, Yi; Gooding, Diane C

    2015-07-30

    The purpose of the present study was to examine the factor structure and the temporal stability of the Chapman psychosis-proneness scales in a representative sample of nonclinical Chinese young adults. The four psychosis-proneness scales evaluated were the Perceptual Aberration (PAS), Magical Ideation (MIS), revised Social Anhedonia (RSAS), and revised Physical Anhedonia (RPAS) scales. The sample consisted of 1724 young adults with a mean age of 18.8 years (S.D. = 0.84). The results of the confirmatory factor analyses indicated that the best fitting model was a two-factor model with positive schizotypy (PER and MIS) scales and negative schizotypy (RSAS and RPAS) scales. The data add to the growing literature indicating that the measurement of schizotypal traits is consistent across cultures. In addition, the results support the measurement invariance of the Chapman psychosis-proneness scales across time, i.e., there was ample evidence of test-retest reliability over a test interval of 6 months. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Expanding the Functionality of Speech Recognition in Radiology: Creating a Real-Time Methodology for Measurement and Analysis of Occupational Stress and Fatigue

    OpenAIRE

    Reiner, Bruce I.

    2012-01-01

    While occupational stress and fatigue have been well described throughout medicine, the radiology community is particularly susceptible due to declining reimbursements, heightened demands for service deliverables, and increasing exam volume and complexity. The resulting occupational stress can be variable in nature and dependent upon a number of intrinsic and extrinsic stressors. Intrinsic stressors largely account for inter-radiologist stress variability and relate to unique attributes of th...

  13. Multi-time Scale Joint Scheduling Method Considering the Grid of Renewable Energy

    Science.gov (United States)

    Zhijun, E.; Wang, Weichen; Cao, Jin; Wang, Xin; Kong, Xiangyu; Quan, Shuping

    2018-01-01

    Renewable new energy power generation prediction error like wind and light, brings difficulties to dispatch the power system. In this paper, a multi-time scale robust scheduling method is set to solve this problem. It reduces the impact of clean energy prediction bias to the power grid by using multi-time scale (day-ahead, intraday, real time) and coordinating the dispatching power output of various power supplies such as hydropower, thermal power, wind power, gas power and. The method adopts the robust scheduling method to ensure the robustness of the scheduling scheme. By calculating the cost of the abandon wind and the load, it transforms the robustness into the risk cost and optimizes the optimal uncertainty set for the smallest integrative costs. The validity of the method is verified by simulation.

  14. Periodic Solution of Second-Order Hamiltonian Systems with a Change Sign Potential on Time Scales

    Directory of Open Access Journals (Sweden)

    You-Hui Su

    2009-01-01

    Full Text Available This paper is concerned with the second-order Hamiltonian system on time scales 𝕋 of the form uΔΔ(ρ(t+μb(t|u(t|μ−2u(t+∇¯H(t,u(t=0, Δ-a.e. t∈[0,T]𝕋 , u(0−u(T=uΔ(ρ(0−uΔ(ρ(T=0, where 0,T∈𝕋. By using the minimax methods in critical theory, an existence theorem of periodic solution for the above system is established. As an application, an example is given to illustrate the result. This is probably the first time the existence of periodic solutions for second-order Hamiltonian system on time scales has been studied by critical theory.

  15. Measuring parent time scarcity and fatigue as barriers to meal planning and preparation: quantitative scale development.

    Science.gov (United States)

    Storfer-Isser, Amy; Musher-Eizenman, Dara

    2013-03-01

    To examine the psychometric properties of 9 quantitative items that assess time scarcity and fatigue as parent barriers to planning and preparing meals for their children. A convenience sample of 342 parents of children aged 2-6 years completed a 20-minute online survey. Exploratory factor analysis was used to examine the factor structure and create summary scales. Internal consistency reliability and measures of construct and concurrent validity were assessed. Two scales were created based on the factor analysis: time and energy for meals and meal planning. Preliminary evidence suggests that both scales are reliable and valid. The time and energy for meals and meal planning scales can be completed quickly by busy and tired parents. As many children do not eat nutritious diets, a better understanding of the barriers that parents face is critical and may help inform interventions tailored to the needs of tired, busy parents. Copyright © 2013 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  16. Hepatic angiomyolipoma: contrast patterns with SonoVue-enhanced real-time gray-scale ultrasonography.

    Science.gov (United States)

    Wei, Rui-Xue; Wang, Wen-Ping; Ding, Hong; Huang, Bei-Jian; Li, Chao-Lun; Fan, Pei-Li; Hou, Jun; He, Nian-An

    2012-01-01

    This study was conducted to retrospectively evaluate the pattern of contrast enhancement with SonoVue on gray-scale ultrasonography of hepatic angiomyolipoma (HAML). Imaging features of 33 pathologically proven HAML lesions in 33 patients who underwent baseline ultrasound and contrast-enhanced ultrasonography (CEUS) were assessed retrospectively. All lesions were enhanced in the arterial phase and showed whole-tumor filling in. Thirty-two of 33 (97%) lesions showed early positive enhancement in the arterial phase. Twenty-three of these exhibited isoechoic or hyperechoic features in the portal phase. HAML demonstrate characteristic manifestations with SonoVue-enhanced real-time gray-scale ultrasonography.

  17. Controller Design of Multiinput Multioutput Time-Delay Large-Scale System

    Directory of Open Access Journals (Sweden)

    Chia-Wei Lin

    2013-01-01

    Full Text Available The paper presents a novel feedback linearization controller of nonlinear multiinput multioutput time-delay large-scale systems to obtain both the tracking and almost disturbance decoupling (ADD performances. The significant contribution of this paper is to build up a control law such that the overall closed-loop system is stable for given initial condition and bounded tracking trajectory with the input-to-state-stability characteristic and almost disturbance decoupling performance. We have simulated the two-inverted-pendulum system coupled by a spring for networked control systems which has been used as a test bed for the study of decentralized control of large-scale systems.

  18. Multi-scale anomaly detection algorithm based on infrequent pattern of time series

    Science.gov (United States)

    Chen, Xiao-Yun; Zhan, Yan-Yan

    2008-04-01

    In this paper, we propose two anomaly detection algorithms PAV and MPAV on time series. The first basic idea of this paper defines that the anomaly pattern is the most infrequent time series pattern, which is the lowest support pattern. The second basic idea of this paper is that PAV detects directly anomalies in the original time series, and MPAV algorithm extraction anomaly in the wavelet approximation coefficient of the time series. For complexity analyses, as the wavelet transform have the functions to compress data, filter noise, and maintain the basic form of time series, the MPAV algorithm, while maintaining the accuracy of the algorithm improves the efficiency. As PAV and MPAV algorithms are simple and easy to realize without training, this proposed multi-scale anomaly detection algorithm based on infrequent pattern of time series can therefore be proved to be very useful for computer science applications.

  19. Measuring time attitudes in Slovenia: Psychometric proprieties of the Adolescent and Adult Time Attitude Scale (AATI-TA

    Directory of Open Access Journals (Sweden)

    Mojca Juriševič

    2017-11-01

    Full Text Available In the present study, we examined the psychometric properties of scores on the newly developed Slovenian version of the Adolescent and Adult Time Inventory-Time Attitudes Scale (AATI-TA in a sample of 182 Slovenian adolescents. The 30-item AATI-TA assesses positive and negative attitudes towards the past, present, and the future. Time attitudes are particularly important in adolescence due to their association with various educational and psychological outcomes. The AATI-TA is a robust instrument and AATI-TA scores have already been validated in several national contexts worldwide. Due to language differences between Slovene and English, a 24-item version of the AATI-TA was examined in Slovenia. As hypothesized, scores on the 24-item Slovenian version of AATI-TA were internally consistent and structurally valid. Moreover, meaningful correlations between time attitudes and positivity, a basic disposition determining individual well-being, provided evidence of concurrent validity. The results suggest that the Slovenian version of the AATI-TA will be useful in Slovenian research examining time attitudes.

  20. Modeling and Validating Time, Buffering, and Utilization of a Large-Scale, Real-Time Data Acquisition System

    CERN Document Server

    AUTHOR|(SzGeCERN)756497; The ATLAS collaboration; Garcia Garcia, Pedro Javier; Vandelli, Wainer; Froening, Holger

    2017-01-01

    Data acquisition systems for large-scale high-energy physics experiments have to handle hundreds of gigabytes per second of data, and are typically implemented as specialized data centers that connect a very large number of front-end electronics devices to an event detection and storage system. The design of such systems is often based on many assumptions, small-scale experiments and a substantial amount of over-provisioning. In this paper, we introduce a discrete event-based simulation tool that models the dataflow of the current ATLAS data acquisition system, with the main goal to be accurate with regard to the main operational characteristics. We measure buffer occupancy counting the number of elements in buffers; resource utilization measuring output bandwidth and counting the number of active processing units, and their time evolution by comparing data over many consecutive and small periods of time. We perform studies on the error in simulation when comparing the results to a large amount of real-world ...

  1. Modeling and Validating Time, Buffering, and Utilization of a Large-Scale, Real-Time Data Acquisition System

    CERN Document Server

    AUTHOR|(SzGeCERN)756497; The ATLAS collaboration; Garcia Garcia, Pedro Javier; Vandelli, Wainer; Froening, Holger

    2017-01-01

    Data acquisition systems for large-scale high-energy physics experiments have to handle hundreds of gigabytes per second of data, and are typically realized as specialized data centers that connect a very large number of front-end electronics devices to an event detection and storage system. The design of such systems is often based on many assumptions, small-scale experiments and a substantial amount of over-provisioning. In this work, we introduce a discrete event-based simulation tool that models the data flow of the current ATLAS data acquisition system, with the main goal to be accurate with regard to the main operational characteristics. We measure buffer occupancy counting the number of elements in buffers, resource utilization measuring output bandwidth and counting the number of active processing units, and their time evolution by comparing data over many consecutive and small periods of time. We perform studies on the error of simulation when comparing the results to a large amount of real-world ope...

  2. Time delay effects on large-scale MR damper based semi-active control strategies

    International Nuclear Information System (INIS)

    Cha, Y-J; Agrawal, A K; Dyke, S J

    2013-01-01

    This paper presents a detailed investigation on the robustness of large-scale 200 kN MR damper based semi-active control strategies in the presence of time delays in the control system. Although the effects of time delay on stability and performance degradation of an actively controlled system have been investigated extensively by many researchers, degradation in the performance of semi-active systems due to time delay has yet to be investigated. Since semi-active systems are inherently stable, instability problems due to time delay are unlikely to arise. This paper investigates the effects of time delay on the performance of a building with a large-scale MR damper, using numerical simulations of near- and far-field earthquakes. The MR damper is considered to be controlled by four different semi-active control algorithms, namely (i) clipped-optimal control (COC), (ii) decentralized output feedback polynomial control (DOFPC), (iii) Lyapunov control, and (iv) simple-passive control (SPC). It is observed that all controllers except for the COC are significantly robust with respect to time delay. On the other hand, the clipped-optimal controller should be integrated with a compensator to improve the performance in the presence of time delay. (paper)

  3. Comparison Study of Braden Scale and Time-to-Erythema Measures in Long-term Care.

    Science.gov (United States)

    Yap, Tracey L; Rapp, Mary Pat; Kennerly, Susan; Cron, Stanley G; Bergstrom, Nancy

    2015-01-01

    The Braden Scale for Predicting Pressure Sore Risk is used to assess risk, and the Centers for Medicare & Medicaid guidelines suggest the use of a tissue tolerance procedure that detects time-to-erythema (TTE) to further refine tissue tolerance, a component of the Braden Scale. The aim of this study was to compare the Braden Scale and TTE as risk classification methods and their utility in identifying care planning interventions. Descriptive study using retrospective chart review. Participants were a convenience sample of 89 adults 65 years or older residing in a long-term care facility in the Midwestern United States. The sample was drawn from a facility-generated list of 90 residents who had both Braden Scale and tissue tolerance testing performed within 24 hours of admission from any setting, readmission after a hospital stay, or performed as part of a routine annual reassessment. Results of staff performance on the Braden Scale and TTE were compared as risk classification methods and based on their utility for identifying care planning interventions. Data were collected during 1 session when TTE and the Braden Scale were completed. Agreement between the 5 risk categories from the Braden Scale and 5 TTE risk categories was analyzed via the kappa statistic and Kendall tau-c statistic. Spearman or Pearson correlation coefficients were calculated as appropriate for ordinal and continuous risk, intervention, and severity measures. The mean Braden Scale score was 17.5 ± 3 (mean ± SD); the mean TTE-Bed was 2.35 ± 0.57 hours and the mean TTE-Chair was 2.18 ± 0.52. Using a Braden Scale score of 18 or less as a cut point for identifying clinically relevant risk for pressure ulcer development, 55 participants were deemed at risk, 62 had mobility subscale scores less than 4, 76 had activity subscale scores less than 4, and 73 were incontinent. The weighted kappa statistic demonstrated weak agreement between TTE-Bed and the Braden Scale Total Score (κ = 0.04; 95% CI: 0

  4. Radiology research in mainland China in the past 10 years: a survey of original articles published in Radiology and European Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Long Jiang; Wang, Yun Fei; Yang, Zhen Lu; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Schoepf, U.J. [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Xu, Jiaqian [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Li, Enzhong [National Natural Science Foundation of China, Department of Medical Science, Beijing (China)

    2017-10-15

    To evaluate the features and trends of Radiology research in Mainland China through bibliometric analysis of the original articles published in Radiology and European Radiology (ER) between 2006 and 2015. We reviewed the original articles published in Radiology and ER between 2006 and 2015. The following information was abstracted: imaging subspecialty, imaging technique(s) used, research type, sample size, study design, statistical analysis, study results, funding declarations, international collaborations, number of authors, department and province of the first author. All variables were examined longitudinally over time. Radiology research in Mainland China saw a substantial increase in original research articles published, especially in the last 5 years (P < 0.001). Within Mainland China's Radiology research, neuroradiology, vascular/interventional Radiology, and abdominal Radiology were the most productive fields; MR imaging was the most used modality, and a distinct geographic provenience was observed for articles published in Radiology and ER. Radiology research in Mainland China has seen substantial growth in the past 5 years with neuroradiology, vascular/interventional Radiology, and abdominal Radiology as the most productive fields. MR imaging is the most used modality. Article provenience shows a distinct geographical pattern. (orig.)

  5. Radiology research in mainland China in the past 10 years: a survey of original articles published in Radiology and European Radiology

    International Nuclear Information System (INIS)

    Zhang, Long Jiang; Wang, Yun Fei; Yang, Zhen Lu; Lu, Guang Ming; Schoepf, U.J.; Xu, Jiaqian; Li, Enzhong

    2017-01-01

    To evaluate the features and trends of Radiology research in Mainland China through bibliometric analysis of the original articles published in Radiology and European Radiology (ER) between 2006 and 2015. We reviewed the original articles published in Radiology and ER between 2006 and 2015. The following information was abstracted: imaging subspecialty, imaging technique(s) used, research type, sample size, study design, statistical analysis, study results, funding declarations, international collaborations, number of authors, department and province of the first author. All variables were examined longitudinally over time. Radiology research in Mainland China saw a substantial increase in original research articles published, especially in the last 5 years (P < 0.001). Within Mainland China's Radiology research, neuroradiology, vascular/interventional Radiology, and abdominal Radiology were the most productive fields; MR imaging was the most used modality, and a distinct geographic provenience was observed for articles published in Radiology and ER. Radiology research in Mainland China has seen substantial growth in the past 5 years with neuroradiology, vascular/interventional Radiology, and abdominal Radiology as the most productive fields. MR imaging is the most used modality. Article provenience shows a distinct geographical pattern. (orig.)

  6. A time-scale sensitometric method for evaluating screen - film systems

    International Nuclear Information System (INIS)

    Goes, E.G.; Pela, C.A.; Ghilardi, N.T.

    1997-01-01

    An x-ray sensitometer is used to measure the characteristic curve of radiographic films exposed with fluorescent intensifying screens. The series of relative exposures, necessary to cover the full density range of the film, can be obtained by either time-scale or intensity-scale sensitometric methods. We have developed a convenient method of exposing film-screen systems for time-scale sensitometry. In this method, during exposure the x-ray kilovoltage, tube current and x-ray intensity remain constant and a geometric series of exposures of the film is modulated by varying the exposure time. This time variation can be obtained when a lead disc with different sector openings is rotated in front of the film system by a stepping motor. The conditions normally used are 70 kVp x-rays, 3.5 mm Al total filtration at the tube, and 2.4 m focal spot-film distance. This exposure latitude gives a complete characteristic curve of film-screen systems. (author)

  7. A time-scale sensitometric method for evaluating screen - film systems

    Energy Technology Data Exchange (ETDEWEB)

    Goes, E.G.; Pela, C.A.; Ghilardi, N.T. [CIDRA - Centro de Instrumentacao, Dosimetria e Radioprotecao, DFM - FFCLRP - USP, Av. Bandeirantes, 3900-14040 901 Ribeirao Preto, SP (Brazil)

    1997-10-01

    An x-ray sensitometer is used to measure the characteristic curve of radiographic films exposed with fluorescent intensifying screens. The series of relative exposures, necessary to cover the full density range of the film, can be obtained by either time-scale or intensity-scale sensitometric methods. We have developed a convenient method of exposing film-screen systems for time-scale sensitometry. In this method, during exposure the x-ray kilovoltage, tube current and x-ray intensity remain constant and a geometric series of exposures of the film is modulated by varying the exposure time. This time variation can be obtained when a lead disc with different sector openings is rotated in front of the film system by a stepping motor. The conditions normally used are 70 kVp x-rays, 3.5 mm Al total filtration at the tube, and 2.4 m focal spot-film distance. This exposure latitude gives a complete characteristic curve of film-screen systems. (author)

  8. Development of automatic intercomparison system for generation of time scale ensembling several atomic clocks

    Directory of Open Access Journals (Sweden)

    Thorat P.P.

    2015-01-01

    Full Text Available National physical laboratory India (NPLI has five commercial cesium atomic clocks. Till recently one of these clocks had been used to maintain coordinated universal time (UTC of NPLI. To utilize all these clocks in an ensemble manner to generate a smoother time scale, it has been essential to inter-compare them very precisely. This has been achieved with an automatic measurement system with well-conceived software. Though few laboratories have developed such automatic measurement system by themselves based on the respective requirements; but they are not reported. So keeping in mind of the specific requirement of the time scale generation, a new system has been developed by NPLI. The design has taken into account of the associated infrastructure that exists and would be used. The performance of the new system has also been studied. It has been found to be quite satisfactory to serve the purpose. The system is being utilized for the generation of time scale of NPLI.

  9. Correcting Spatial Variance of RCM for GEO SAR Imaging Based on Time-Frequency Scaling

    Directory of Open Access Journals (Sweden)

    Ze Yu

    2016-07-01

    Full Text Available Compared with low-Earth orbit synthetic aperture radar (SAR, a geosynchronous (GEO SAR can have a shorter revisit period and vaster coverage. However, relative motion between this SAR and targets is more complicated, which makes range cell migration (RCM spatially variant along both range and azimuth. As a result, efficient and precise imaging becomes difficult. This paper analyzes and models spatial variance for GEO SAR in the time and frequency domains. A novel algorithm for GEO SAR imaging with a resolution of 2 m in both the ground cross-range and range directions is proposed, which is composed of five steps. The first is to eliminate linear azimuth variance through the first azimuth time scaling. The second is to achieve RCM correction and range compression. The third is to correct residual azimuth variance by the second azimuth time-frequency scaling. The fourth and final steps are to accomplish azimuth focusing and correct geometric distortion. The most important innovation of this algorithm is implementation of the time-frequency scaling to correct high-order azimuth variance. As demonstrated by simulation results, this algorithm can accomplish GEO SAR imaging with good and uniform imaging quality over the entire swath.

  10. Modeling Climate Responses to Spectral Solar Forcing on Centennial and Decadal Time Scales

    Science.gov (United States)

    Wen, G.; Cahalan, R.; Rind, D.; Jonas, J.; Pilewskie, P.; Harder, J.

    2012-01-01

    We report a series of experiments to explore clima responses to two types of solar spectral forcing on decadal and centennial time scales - one based on prior reconstructions, and another implied by recent observations from the SORCE (Solar Radiation and Climate Experiment) SIM (Spectral 1rradiance Monitor). We apply these forcings to the Goddard Institute for Space Studies (GISS) Global/Middle Atmosphere Model (GCMAM). that couples atmosphere with ocean, and has a model top near the mesopause, allowing us to examine the full response to the two solar forcing scenarios. We show different climate responses to the two solar forCing scenarios on decadal time scales and also trends on centennial time scales. Differences between solar maximum and solar minimum conditions are highlighted, including impacts of the time lagged reSponse of the lower atmosphere and ocean. This contrasts with studies that assume separate equilibrium conditions at solar maximum and minimum. We discuss model feedback mechanisms involved in the solar forced climate variations.

  11. Modeling and simulation of nuclear fuel in scenarios with long time scales

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, Carlos E.; Bodmann, Bardo E.J., E-mail: eduardo.espinosa@ufrgs.br, E-mail: bardo.bodmann@ufrgs.br [Universidade Federal do Rio Grande do Sul (DENUC/PROMEC/UFRGS), Porto Alegre, RS (Brazil). Departamento de Engenharia Nuclear. Programa de Pos Graduacao em Engenharia Mecanica

    2015-07-01

    Nuclear reactors play a key role in defining the energy matrix. A study by the Fraunhofer Society shows in different time scales for long periods of time the distribution of energy sources. Regardless of scale, the use of nuclear energy is practically constant. In these scenarios, the nuclear fuel behavior over time is of interest. For kinetics of long-term scales, changing the chemical composition of fuel is significant. Thus, it is appropriate to consider fission products called neutron poisons. Such products are of interest in the nuclear reactor, since they become parasitic neutron absorbers and result in long thermal heat sources. The objective of this work is to solve the kinetics system coupled to neutron poison products. To solve this system, we use similar ideas to the method of Adomian decomposition. Initially, one separates the system of equations as the sum of a linear part and a non-linear part in order to solve a recursive system. The nonlinearity is treated as Adomian polynomial. We present numerical results of the effects of changing the power of a reactor, scenarios such as start-up and shut-down. For these results we consider time dependent reactivity, such as linear reactivity, quadratic polynomial and oscillatory. With these results one can simulate the chemical composition of the fuel due to the reuse of the spent fuel in subsequent cycles. (author)

  12. Radiological Dispersion Devices: are we prepared?

    International Nuclear Information System (INIS)

    Sohier, Alain; Hardeman, Frank

    2006-01-01

    Already before the events of September 11th 2001 concern was raised about the spread of orphan sources and their potential use in Radiological Dispersion Devices by terrorist groups. Although most of the simulated scenarios foresee a rather limited direct health impact on the population, the affected region would suffer from the indirect consequences such as social disruption, cleanup requirements and economic costs. The nature of such a radiological attack would anyway be different compared to conventional radiological accidents, basically because it can happen anywhere at any time. Part of the response resides in a general preparedness scheme incorporating attacks with Radiological Dispersion Devices. Training of different potential intervention teams is essential. The response would consist of a prioritised list of actions adapted to the circumstances. As the psychosocial dimension of the crisis could be worse than the purely radiological one, an adapted communication strategy with the public aspect would be a key issue

  13. Time-Sliced Perturbation Theory for Large Scale Structure I: General Formalism

    CERN Document Server

    Blas, Diego; Ivanov, Mikhail M.; Sibiryakov, Sergey

    2016-01-01

    We present a new analytic approach to describe large scale structure formation in the mildly non-linear regime. The central object of the method is the time-dependent probability distribution function generating correlators of the cosmological observables at a given moment of time. Expanding the distribution function around the Gaussian weight we formulate a perturbative technique to calculate non-linear corrections to cosmological correlators, similar to the diagrammatic expansion in a three-dimensional Euclidean quantum field theory, with time playing the role of an external parameter. For the physically relevant case of cold dark matter in an Einstein--de Sitter universe, the time evolution of the distribution function can be found exactly and is encapsulated by a time-dependent coupling constant controlling the perturbative expansion. We show that all building blocks of the expansion are free from spurious infrared enhanced contributions that plague the standard cosmological perturbation theory. This pave...

  14. REAL-TIME VIDEO SCALING BASED ON CONVOLUTION NEURAL NETWORK ARCHITECTURE

    Directory of Open Access Journals (Sweden)

    S Safinaz

    2017-08-01

    Full Text Available In recent years, video super resolution techniques becomes mandatory requirements to get high resolution videos. Many super resolution techniques researched but still video super resolution or scaling is a vital challenge. In this paper, we have presented a real-time video scaling based on convolution neural network architecture to eliminate the blurriness in the images and video frames and to provide better reconstruction quality while scaling of large datasets from lower resolution frames to high resolution frames. We compare our outcomes with multiple exiting algorithms. Our extensive results of proposed technique RemCNN (Reconstruction error minimization Convolution Neural Network shows that our model outperforms the existing technologies such as bicubic, bilinear, MCResNet and provide better reconstructed motioning images and video frames. The experimental results shows that our average PSNR result is 47.80474 considering upscale-2, 41.70209 for upscale-3 and 36.24503 for upscale-4 for Myanmar dataset which is very high in contrast to other existing techniques. This results proves our proposed model real-time video scaling based on convolution neural network architecture’s high efficiency and better performance.

  15. Poul Erik Andersen's radiological work on Osteochondrodysplasias and interventional radiology

    DEFF Research Database (Denmark)

    Andersen, Poul Erik

    2011-01-01

    Hospital. His significant experience and extensive scientific work has led to many posts in the Danish Society of Interventional Radiology, the European Society of Radiology and the Cardiovascular and Interventional Radiological Society of Europe, where he is a fellow and has passed the European Board...... of Interventional Radiology - The European qualification in Interventional Radiology....

  16. Towards a High-resolution Time Scale for the Early Devonian

    Science.gov (United States)

    Dekkers, M. J.; da Silva, A. C.

    2017-12-01

    High-resolution time scales are crucial to understand Earth's history in detail. The construction of a robust geological time scale, however, inevitably becomes increasingly harder further back in time. Uncertainties associated with anchor radiometric ages increase in size, not speaking of the mere presence of suitable datable strata. However, durations of stages can be tightly constrained by making use of cyclic expressions in sediments, an approach that revolutionized the Cenozoic time scale. When precisely determined durations are stitched together, ultimately, a very precise time scale is the result. For the Mesozoic and Paleozoic an astronomical solution as a tuning target is not available but the dominant periods of eccentricity, obliquity and precession are reasonably well constrained for the entire Phanerozoic which enables their detection by means of spectral analysis. Eccentricity is time-invariant and is used as the prime building block. Here we focus on the Early Devonian, on its lowermost three stages: the Lochkovian, Pragian and Emsian. The uncertainties on the Devonian stage boundaries are currently in the order of several millions of years. The preservation of climatic cycles in diagenetically or even anchimetamorphically affected successions, however, is essential. The fit of spectral peak ratios with those calculated for orbital cycles, is classically used as a strong argument for a preserved climatic signal. Here we use primarily the low field magnetic susceptibility (MS) as proxy parameter, supported by gamma-ray spectrometry to test for consistency. Continuous Wavelet Transform, Evolutive Harmonic Analysis, Multitaper Method, and Average Spectral Misfit are used to reach an optimal astronomical interpretation. We report on classic Early Devonian sections from the Czech Republic: the Pozar-CS (Lochkovian and Pragian), Pod Barrandovem (Pragian and Lower Emsian), and Zlichov (Middle-Upper Emsian). Also a Middle-Upper Emsian section from the US

  17. Socioeconomic trends in radiology

    International Nuclear Information System (INIS)

    Barneveld Binkhuysen, F.H.

    1998-01-01

    For radiology the socioeconomic environment is a topic of increasing importance. In addition to the well-known important scientific developments in radiology such as interventional MRI, several other major trends can be recognized: (1) changes in the delivery of health care, in which all kinds of managed care are developing and will influence the practice of radiology, and (2) the process of computerization and digitization. The socioeconomic environment of radiology will be transformed by the developments in managed care, teleradiology and the integration of information systems. If radiologists want to manage future radiology departments they must have an understanding of the changes in the fields of economics and politics that are taking place and that will increasingly influence radiology. Some important and recognizable aspects of these changes will be described here. (orig.)

  18. Consistent allometric scaling of stomatal sizes and densities across taxonomic ranks and geologic time

    Science.gov (United States)

    de Boer, H. J.; Price, C. A.; Wagner-Cremer, F.; Dekker, S. C.; Veneklaas, E. J.

    2013-12-01

    Stomatal pores on plants leaves are an important link in the chain of processes that determine biosphere fluxes of water and carbon. Stomatal density (i.e. the number of stomata per area) and the size of the stomatal pore at maximum aperture are particularly relevant traits in this context because they determine the theoretical maximum diffusive stomatal conductance (gsmax) and thereby set an upper limit for leaf gas exchange. Observations on (sub)fossil leaves revealed that changes in stomatal densities are anti-correlated with changes in stomatal sizes at developmental and evolutionary timescales. Moreover, this anti-correlation appears consistently within single species, across multiple species in the extant plant community and at evolutionary time scales. The consistency of the relation between stomatal densities and sizes suggests that common mechanisms constrain the adaptation of these traits across the plant community. In an attempt to identify such potential generic constraints, we investigated the allometry between stomatal densities and sizes in the extant plant community and across geological time. As the size of the stomatal pore at maximum aperture is typically derived from the length of the stomatal pore, we considered the allometric scaling of pore length (lp) with stomatal density (Ds) as the power law: lp = k . Dsa in which k is a normalization constant and the exponent a is the slope of the scaling relation. Our null-hypothesis predicts that stomatal density and pore length scale along a constant slope of -1/2 based on a scale-invariant relation between pore length and the distance between neighboring pores. Our alternative hypothesis predicts a constant slope of -1 based on the idea that stomatal density and pore length scale along an invariant gsmax. To explore these scaling hypotheses in the extant plant community we compiled a dataset of combined observations of stomatal density and pore length on 111 species from published literature and new

  19. Multiple-Time-Scales Hierarchical Frequency Stability Control Strategy of Medium-Voltage Isolated Microgrid

    DEFF Research Database (Denmark)

    Zhao, Zhuoli; Yang, Ping; Guerrero, Josep M.

    2016-01-01

    In this paper, an islanded medium-voltage (MV) microgrid placed in Dongao Island is presented, which integrates renewable-energy-based distributed generations (DGs), energy storage system (ESS), and local loads. In an isolated microgrid without connection to the main grid to support the frequency....... In this way, dynamic stability control that cope with disturbances in short-time scale is implemented by microgrid central controller (MGCC) within Zone B and Zone C. Meanwhile, steady-state stability control to solve the peaks and valleys problem of loads and DGs in long-time scale is executed by microgrid...... energy management system (MEMS) within Zone A. Furthermore, based on the developed complete small-signal state-space model, sensitivity analysis of the eigenvalues is conducted in order to reveal the dynamic stability margin of the MV microgrid, and to identify the proper range of the control parameters...

  20. Chaos anticontrol and synchronization of three time scales brushless DC motor system

    International Nuclear Information System (INIS)

    Ge Zhengming; Cheng Juiwen; Chen Yensheng

    2004-01-01

    Chaos anticontrol of three time scale brushless dc motors and chaos synchronization of different order systems are studied. Nondimensional dynamic equations of three time scale brushless DC motor system are presented. Using numerical results, such as phase diagram, bifurcation diagram, and Lyapunov exponent, periodic and chaotic motions can be observed. By adding constant term, periodic square wave, the periodic triangle wave, the periodic sawtooth wave, and kx vertical bar x vertical bar term, to achieve anticontrol of chaotic or periodic systems, it is found that more chaotic phenomena of the system can be observed. Then, by coupled terms and linearization of error dynamics, we obtain the partial synchronization of two different order systems, i.e. brushless DC motor system and rate gyroscope system

  1. Past and future changes in streamflow in the U.S. Midwest: Bridging across time scales

    Science.gov (United States)

    Villarini, G.; Slater, L. J.; Salvi, K. A.

    2017-12-01

    Streamflows have increased notably across the U.S. Midwest over the past century, principally due to changes in precipitation and land use / land cover. Improving our understanding of the physical drivers that are responsible for the observed changes in discharge may enhance our capability of predicting and projecting these changes, and may have large implications for water resources management over this area. This study will highlight our efforts towards the statistical attribution of changes in discharge across the U.S. Midwest, with analyses performed at the seasonal scale from low to high flows. The main drivers of changing streamflows that we focus on are: urbanization, agricultural land cover, basin-averaged temperature, basin-averaged precipitation, and antecedent soil moisture. Building on the insights from this attribution, we will examine the potential predictability of streamflow across different time scales, with lead times ranging from seasonal to decadal, and discuss a potential path forward for engineering design for future conditions.

  2. Virtual water trade and time scales for loss of water sustainability: a comparative regional analysis.

    Science.gov (United States)

    Goswami, Prashant; Nishad, Shiv Narayan

    2015-03-20

    Assessment and policy design for sustainability in primary resources like arable land and water need to adopt long-term perspective; even small but persistent effects like net export of water may influence sustainability through irreversible losses. With growing consumption, this virtual water trade has become an important element in the water sustainability of a nation. We estimate and contrast the virtual (embedded) water trades of two populous nations, India and China, to present certain quantitative measures and time scales. Estimates show that export of embedded water alone can lead to loss of water sustainability. With the current rate of net export of water (embedded) in the end products, India is poised to lose its entire available water in less than 1000 years; much shorter time scales are implied in terms of water for production. The two cases contrast and exemplify sustainable and non-sustainable virtual water trade in long term perspective.

  3. Virtual water trade and time scales for loss of water sustainability: A comparative regional analysis

    Science.gov (United States)

    Goswami, Prashant; Nishad, Shiv Narayan

    2015-03-01

    Assessment and policy design for sustainability in primary resources like arable land and water need to adopt long-term perspective; even small but persistent effects like net export of water may influence sustainability through irreversible losses. With growing consumption, this virtual water trade has become an important element in the water sustainability of a nation. We estimate and contrast the virtual (embedded) water trades of two populous nations, India and China, to present certain quantitative measures and time scales. Estimates show that export of embedded water alone can lead to loss of water sustainability. With the current rate of net export of water (embedded) in the end products, India is poised to lose its entire available water in less than 1000 years; much shorter time scales are implied in terms of water for production. The two cases contrast and exemplify sustainable and non-sustainable virtual water trade in long term perspective.

  4. Evidence-based radiology: why and how?

    International Nuclear Information System (INIS)

    Sardanelli, Francesco; Di Leo, Giovanni; Hunink, Myriam G.; Gilbert, Fiona J.; Krestin, Gabriel P.

    2010-01-01

    To provide an overview of evidence-based medicine (EBM) in relation to radiology and to define a policy for adoption of this principle in the European radiological community. Starting from Sackett's definition of EBM we illustrate the top-down and bottom-up approaches to EBM as well as EBM's limitations. Delayed diffusion and peculiar features of evidence-based radiology (EBR) are defined with emphasis on the need to shift from the demonstration of the increasing ability to see more and better, to the demonstration of a significant change in treatment planning or, at best, of a significant gain in patient outcome. The ''as low as reasonably achievable'' (ALARA) principle is thought as a dimension of EBR while EBR is proposed as part of the core curriculum of radiology residency. Moreover, we describe the process of health technology assessment in radiology with reference to the six-level scale of hierarchy of studies on diagnostic tests, the main sources of bias in studies on diagnostic performance, and levels of evidence and degrees of recommendations according to the Centre for Evidence-Based Medicine (Oxford, UK) as well as the approach proposed by the GRADE working group. Problems and opportunities offered by evidence-based guidelines in radiology are considered. Finally, we suggest nine points to be actioned by the ESR in order to promote EBR. Radiology will benefit greatly from the improvement in practice that will result from adopting this more rigorous approach to all aspects of our work. (orig.)

  5. Radiology in Medical Education: A Pediatric Radiology Elective as a Template for Other Radiology Courses.

    Science.gov (United States)

    Hilmes, Melissa A; Hyatt, Eddie; Penrod, Cody H; Fleming, Amy E; Singh, Sudha P

    2016-03-01

    Traditionally, the pediatric radiology elective for medical students and pediatric residents constituted a morning teaching session focused mainly on radiography and fluoroscopy. A more structured elective was desired to broaden the exposure to more imaging modalities, create a more uniform educational experience, and include assessment tools. In 2012, an introductory e-mail and formal syllabus, including required reading assignments, were sent to participants before the start date. A rotating weekly schedule was expanded to include cross-sectional imaging (ultrasound, CT, MR) and nuclear medicine. The schedule could accommodate specific goals of the pediatric resident or medical student, as requested. Starting in 2013, an online pre-test and post-test were developed, as well as an online end-of-rotation survey specific to the pediatric radiology elective. Taking the Image Gently pledge was required. A scavenger hunt tool, cue cards, and electronic modules were added. Pre-test and post-test scores, averaged over 2 years, showed improvement in radiology knowledge, with scores increasing by 27% for medical students and 21% for pediatric residents. Surveys at the end of the elective were overwhelmingly positive, with constructive criticism and complimentary comments. We have successfully created an elective experience in radiology that dedicates time to education while preserving the workflow of radiologists. We have developed tools to provide a customized experience with many self-directed learning opportunities. Our tools and techniques are easily translatable to a general or adult radiology elective. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  6. Emergency pediatric radiology

    Energy Technology Data Exchange (ETDEWEB)

    Carty, H. [ed.

    1999-11-01

    This unique book covers the main clinical presentations of children to an emergency room and considers in detail the radiological investigation of such emergencies. Numerous high-quality illustrations of the radiological manifestations of acutely presenting illness in children ensure that the volume will serve as a rapid reference source for both pediatricians and radiologists. All of the authors are specialist pediatric radiologists who provide emergency radiological services on a daily basis, and the text reflects this level of expertise. (orig.)

  7. Essentials of skeletal radiology

    Energy Technology Data Exchange (ETDEWEB)

    Yochum, T.R.; Rowe, L.J.

    1987-01-01

    This book discusses the following topics of skeletal radiology: Positioning of patients for diagnostic radiology and normal anatomy; congenital malformations of skeleton; measurements in radiology; spondylolisthesis; metabolic and endocrine diseases of bone and their diagnostic aspects; image processing of vertebrae, skeleton, bone fractures evaluations and epidemiological and social aspects of some bone diseases. Various modalities as CT scanning, NMR imaging, ultrasonography and biomedical radiography are briefly discussed in relation to bone pathology.

  8. A multi scale approximation solution for the time dependent Boltzmann-transport equation

    International Nuclear Information System (INIS)

    Merk, B.

    2004-03-01

    The basis of all transient simulations for nuclear reactor cores is the reliable calculation of the power production. The local power distribution is generally calculated by solving the space, time, energy and angle dependent neutron transport equation known as Boltzmann equation. The computation of exact solutions of the Boltzmann equation is very time consuming. For practical numerical simulations approximated solutions are usually unavoidable. The objective of this work is development of an effective multi scale approximation solution for the Boltzmann equation. Most of the existing methods are based on separation of space and time. The new suggested method is performed without space-time separation. This effective approximation solution is developed on the basis of an expansion for the time derivative of different approximations to the Boltzmann equation. The method of multiple scale expansion is used for the expansion of the time derivative, because the problem of the stiff time behaviour can't be expressed by standard expansion methods. This multiple scale expansion is used in this work to develop approximation solutions for different approximations of the Boltzmann equation, starting from the expansion of the point kinetics equations. The resulting analytic functions are used for testing the applicability and accuracy of the multiple scale expansion method for an approximation solution with 2 delayed neutron groups. The results are tested versus the exact analytical results for the point kinetics equations. Very good agreement between both solutions is obtained. The validity of the solution with 2 delayed neutron groups to approximate the behaviour of the system with 6 delayed neutron groups is demonstrated in an additional analysis. A strategy for a solution with 4 delayed neutron groups is described. A multiple scale expansion is performed for the space-time dependent diffusion equation for one homogenized cell with 2 delayed neutron groups. The result is

  9. Risks from dental radiology

    International Nuclear Information System (INIS)

    Costa, Tamara Goularte

    2013-01-01

    The objective of this research is to demonstrate the risks and consequences of exposure to dental X-ray. The methodology used was the survey of bibliographic literature on this matter. First, we tried to understand the operation and characteristics of dental X-rays. Afterwards, we tried to know about the risks that this procedure offers to workers and patients. And concluded with the consequences of such exposure. The results showed that dental x-rays only offer risks in prolonged exposure, can affect the worker or patient to pathologies such as cancer or a life-time decreased due to the stochastic effect. Therefore, radiological protection standards must be respected and practised. (author)

  10. Disconjugacy, transformations and quadratic functionals for symplectic dynamicsystems on time scales

    Czech Academy of Sciences Publication Activity Database

    Došlý, Ondřej; Hilscher, R.

    2001-01-01

    Roč. 7, č. 2 (2001), s. 265-295 ISSN 1023-6198 R&D Projects: GA ČR GA201/98/0677; GA ČR GA201/99/0295 Keywords : symplectic dynamic system%time scale% quadratic functional Subject RIV: BA - General Mathematics Impact factor: 0.325, year: 2001 http://www.tandfonline.com/doi/abs/10.1080/10236190108808273

  11. On submersivity assumption for nonlinear control systems on homogeneous time scales

    Czech Academy of Sciences Publication Activity Database

    Kotta, U.; Rehák, Branislav; Wyrwas, M.

    2011-01-01

    Roč. 60, č. 1 (2011), s. 25-37 ISSN 1736-6046 Grant - others:ISPS(XE) PE 10022 Institutional research plan: CEZ:AV0Z10750506 Keywords : time scale * nonlinear system * submersion * submersive system. Subject RIV: BC - Control Systems Theory Impact factor: 0.488, year: 2011 http://library.utia.cas.cz/separaty/2011/TR/rehak-0366024.pdf

  12. Nonlinearities in Drug Release Process from Polymeric Microparticles: Long-Time-Scale Behaviour

    Directory of Open Access Journals (Sweden)

    Elena Simona Bacaita

    2012-01-01

    Full Text Available A theoretical model of the drug release process from polymeric microparticles (a particular type of polymer matrix, through dispersive fractal approximation of motion, is built. As a result, the drug release process takes place through cnoidal oscillations modes of a normalized concentration field. This indicates that, in the case of long-time-scale evolutions, the drug particles assemble in a lattice of nonlinear oscillators occur macroscopically, through variations of drug concentration. The model is validated by experimental results.

  13. A typology of time-scale mismatches and behavioral interventions to diagnose and solve conservation problems

    Science.gov (United States)

    Wilson, Robyn S.; Hardisty, David J.; Epanchin-Niell, Rebecca S.; Runge, Michael C.; Cottingham, Kathryn L.; Urban, Dean L.; Maguire, Lynn A.; Hastings, Alan; Mumby, Peter J.; Peters, Debra P.C.

    2016-01-01

    Ecological systems often operate on time scales significantly longer or shorter than the time scales typical of human decision making, which causes substantial difficulty for conservation and management in socioecological systems. For example, invasive species may move faster than humans can diagnose problems and initiate solutions, and climate systems may exhibit long-term inertia and short-term fluctuations that obscure learning about the efficacy of management efforts in many ecological systems. We adopted a management-decision framework that distinguishes decision makers within public institutions from individual actors within the social system, calls attention to the ways socioecological systems respond to decision makers’ actions, and notes institutional learning that accrues from observing these responses. We used this framework, along with insights from bedeviling conservation problems, to create a typology that identifies problematic time-scale mismatches occurring between individual decision makers in public institutions and between individual actors in the social or ecological system. We also considered solutions that involve modifying human perception and behavior at the individual level as a means of resolving these problematic mismatches. The potential solutions are derived from the behavioral economics and psychology literature on temporal challenges in decision making, such as the human tendency to discount future outcomes at irrationally high rates. These solutions range from framing environmental decisions to enhance the salience of long-term consequences, to using structured decision processes that make time scales of actions and consequences more explicit, to structural solutions aimed at altering the consequences of short-sighted behavior to make it less appealing. Additional application of these tools and long-term evaluation measures that assess not just behavioral changes but also associated changes in ecological systems are needed.

  14. Chaos synchronization and parameter identification of three time scales brushless DC motor system

    International Nuclear Information System (INIS)

    Ge, Z.-M.; Cheng, J.-W.

    2005-01-01

    Chaotic anticontrol and chaos synchronization of brushless DC motor system are studied in this paper. Nondimensional dynamic equations of three time scale brushless DC motor system are presented. Using numerical results, such as phase diagram, bifurcation diagram, and Lyapunov exponent, periodic and chaotic motions can be observed. Then, chaos synchronization of two identical systems via additional inputs and Lyapunov stability theory are studied. And further, the parameter of the system is traced via adaptive control and random optimization method

  15. Scaling of black silicon processing time by high repetition rate femtosecond lasers

    Directory of Open Access Journals (Sweden)

    Nava Giorgio

    2013-11-01

    Full Text Available Surface texturing of silicon substrates is performed by femtosecond laser irradiation at high repetition rates. Various fabrication parameters are optimized in order to achieve very high absorptance in the visible region from the micro-structured silicon wafer as compared to the unstructured one. A 70-fold reduction of the processing time is demonstrated by increasing the laser repetition rate from 1 kHz to 200 kHz. Further scaling up to 1 MHz can be foreseen.

  16. Timing of Formal Phase Safety Reviews for Large-Scale Integrated Hazard Analysis

    Science.gov (United States)

    Massie, Michael J.; Morris, A. Terry

    2010-01-01

    Integrated hazard analysis (IHA) is a process used to identify and control unacceptable risk. As such, it does not occur in a vacuum. IHA approaches must be tailored to fit the system being analyzed. Physical, resource, organizational and temporal constraints on large-scale integrated systems impose additional direct or derived requirements on the IHA. The timing and interaction between engineering and safety organizations can provide either benefits or hindrances to the overall end product. The traditional approach for formal phase safety review timing and content, which generally works well for small- to moderate-scale systems, does not work well for very large-scale integrated systems. This paper proposes a modified approach to timing and content of formal phase safety reviews for IHA. Details of the tailoring process for IHA will describe how to avoid temporary disconnects in major milestone reviews and how to maintain a cohesive end-to-end integration story particularly for systems where the integrator inherently has little to no insight into lower level systems. The proposal has the advantage of allowing the hazard analysis development process to occur as technical data normally matures.

  17. Incipient multiple fault diagnosis in real time with applications to large-scale systems

    International Nuclear Information System (INIS)

    Chung, H.Y.; Bien, Z.; Park, J.H.; Seon, P.H.

    1994-01-01

    By using a modified signed directed graph (SDG) together with the distributed artificial neutral networks and a knowledge-based system, a method of incipient multi-fault diagnosis is presented for large-scale physical systems with complex pipes and instrumentations such as valves, actuators, sensors, and controllers. The proposed method is designed so as to (1) make a real-time incipient fault diagnosis possible for large-scale systems, (2) perform the fault diagnosis not only in the steady-state case but also in the transient case as well by using a concept of fault propagation time, which is newly adopted in the SDG model, (3) provide with highly reliable diagnosis results and explanation capability of faults diagnosed as in an expert system, and (4) diagnose the pipe damage such as leaking, break, or throttling. This method is applied for diagnosis of a pressurizer in the Kori Nuclear Power Plant (NPP) unit 2 in Korea under a transient condition, and its result is reported to show satisfactory performance of the method for the incipient multi-fault diagnosis of such a large-scale system in a real-time manner

  18. A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

    Directory of Open Access Journals (Sweden)

    Yongxin Chou

    2017-01-01

    Full Text Available Base scale entropy analysis (BSEA is a nonlinear method to analyze heart rate variability (HRV signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.

  19. Effects of moonlight on the capturability of frugivorous phyllostomid bats (Chiroptera: Phyllostomidae at different time scales

    Directory of Open Access Journals (Sweden)

    Marco A. R. Mello

    2013-08-01

    Full Text Available Some bat species seem to be lunar phobic, i.e., they avoid flying in bright areas or during bright periods of the night; however, the evidence is still controversial. We think that part of this controversy comes from pooling data on bat captures and moonlight intensity according to broad categories, such as moon phases, which conceal the high variability among nights. Therefore, we used detailed, long-term field data on three phyllostomid bat species, in order to test the hypothesis of lunar phobia at two different time scales: 1 among nights, by pooling data of different nights according to moon phases and testing for differences in the distribution of captures; and 2 within a night, by analyzing the relationship between capturability and moonlight intensity (measured as illuminance in one-hour intervals for 29 individual nights. Although most captures of the studied bat species occurred in the first half of the night, their activity pattern varied largely among nights, and was not always unimodal as commonly assumed. At the larger time scale, all studied bat species showed evidence of lunar phobia, as they were more frequently captured on dark moon phases. Nevertheless, at the smaller time scale, only Carollia perspicillata (Linnaeus, 1758 was less frequently captured on brighter periods of the night. We propose that the unimodal activity pattern assumed for frugivorous phyllostomid bats may be an artifact of data organization, and that activity and lunar phobia are much more variable than previously assumed.

  20. Relative Time-scale for Channeling Events Within Chaotic Terrains, Margaritifer Sinus, Mars

    Science.gov (United States)

    Janke, D.

    1985-01-01

    A relative time scale for ordering channel and chaos forming events was constructed for areas within the Margaritifer Sinus region of Mars. Transection and superposition relationships of channels, chaotic terrain, and the surfaces surrounding them were used to create the relative time scale; crater density studies were not used. Channels and chaos in contact with one another were treated as systems. These systems were in turn treated both separately (in order to understand internal relationships) and as members of the suite of Martian erosional forms (in order to produce a combined, master time scale). Channeling events associated with chaotic terrain development occurred over an extended geomorphic period. The channels can be divided into three convenient groups: those that pre-date intercrater plains development post-plains, pre-chasma systems; and those associated with the development of the Vallis Marineris chasmata. No correlations with cyclic climatic changes, major geologic events in other regions on Mars, or triggering phenomena (for example, specific impact events) were found.

  1. A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

    Science.gov (United States)

    Zhang, Ruilei; Feng, Yufeng; Lu, Zhenli

    2017-01-01

    Base scale entropy analysis (BSEA) is a nonlinear method to analyze heart rate variability (HRV) signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV) signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA) by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE) for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices. PMID:29065639

  2. A multi-time-scale analysis of chemical reaction networks: II. Stochastic systems.

    Science.gov (United States)

    Kan, Xingye; Lee, Chang Hyeong; Othmer, Hans G

    2016-11-01

    We consider stochastic descriptions of chemical reaction networks in which there are both fast and slow reactions, and for which the time scales are widely separated. We develop a computational algorithm that produces the generator of the full chemical master equation for arbitrary systems, and show how to obtain a reduced equation that governs the evolution on the slow time scale. This is done by applying a state space decomposition to the full equation that leads to the reduced dynamics in terms of certain projections and the invariant distributions of the fast system. The rates or propensities of the reduced system are shown to be the rates of the slow reactions conditioned on the expectations of fast steps. We also show that the generator of the reduced system is a Markov generator, and we present an efficient stochastic simulation algorithm for the slow time scale dynamics. We illustrate the numerical accuracy of the approximation by simulating several examples. Graph-theoretic techniques are used throughout to describe the structure of the reaction network and the state-space transitions accessible under the dynamics.

  3. Global stability analysis and robust design of multi-time-scale biological networks under parametric uncertainties.

    Science.gov (United States)

    Meyer-Baese, Anke; Koshkouei, Ali J; Emmett, Mark R; Goodall, David P

    2009-01-01

    Biological networks are prone to internal parametric fluctuations and external noises. Robustness represents a crucial property of these networks, which militates the effects of internal fluctuations and external noises. In this paper biological networks are formulated as coupled nonlinear differential systems operating at different time-scales under vanishing perturbations. In contrast to previous work viewing biological parametric uncertain systems as perturbations to a known nominal linear system, the perturbed biological system is modeled as nonlinear perturbations to a known nonlinear idealized system and is represented by two time-scales (subsystems). In addition, conditions for the existence of a global uniform attractor of the perturbed biological system are presented. By using an appropriate Lyapunov function for the coupled system, a maximal upper bound for the fast time-scale associated with the fast state is derived. The proposed robust system design principles are potentially applicable to robust biosynthetic network design. Finally, two examples of two important biological networks, a neural network and a gene regulatory network, are presented to illustrate the applicability of the developed theoretical framework.

  4. Machine Learning and Radiology

    Science.gov (United States)

    Wang, Shijun; Summers, Ronald M.

    2012-01-01

    In this paper, we give a short introduction to machine learning and survey its applications in radiology. We focused on six categories of applications in radiology: medical image segmentation, registration, computer aided detection and diagnosis, brain function or activity analysis and neurological disease diagnosis from fMR images, content-based image retrieval systems for CT or MRI images, and text analysis of radiology reports using natural language processing (NLP) and natural language understanding (NLU). This survey shows that machine learning plays a key role in many radiology applications. Machine learning identifies complex patterns automatically and helps radiologists make intelligent decisions on radiology data such as conventional radiographs, CT, MRI, and PET images and radiology reports. In many applications, the performance of machine learning-based automatic detection and diagnosis systems has shown to be comparable to that of a well-trained and experienced radiologist. Technology development in machine learning and radiology will benefit from each other in the long run. Key contributions and common characteristics of machine learning techniques in radiology are discussed. We also discuss the problem of translating machine learning applications to the radiology clinical setting, including advantages and potential barriers. PMID:22465077

  5. Radiological Emergency Response Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Quality Data Asset includes all current and historical emergency radiological response event and incident of national significance data and surveillance, monitoring,...

  6. Machine learning and radiology.

    Science.gov (United States)

    Wang, Shijun; Summers, Ronald M

    2012-07-01

    In this paper, we give a short introduction to machine learning and survey its applications in radiology. We focused on six categories of applications in radiology: medical image segmentation, registration, computer aided detection and diagnosis, brain function or activity analysis and neurological disease diagnosis from fMR images, content-based image retrieval systems for CT or MRI images, and text analysis of radiology reports using natural language processing (NLP) and natural language understanding (NLU). This survey shows that machine learning plays a key role in many radiology applications. Machine learning identifies complex patterns automatically and helps radiologists make intelligent decisions on radiology data such as conventional radiographs, CT, MRI, and PET images and radiology reports. In many applications, the performance of machine learning-based automatic detection and diagnosis systems has shown to be comparable to that of a well-trained and experienced radiologist. Technology development in machine learning and radiology will benefit from each other in the long run. Key contributions and common characteristics of machine learning techniques in radiology are discussed. We also discuss the problem of translating machine learning applications to the radiology clinical setting, including advantages and potential barriers. Copyright © 2012. Published by Elsevier B.V.

  7. Mobile computing for radiology.

    Science.gov (United States)

    Auffermann, William F; Chetlen, Alison L; Sharma, Arjun; Colucci, Andrew T; DeQuesada, Ivan M; Grajo, Joseph R; Kung, Justin W; Loehfelm, Thomas W; Sherry, Steven J

    2013-12-01

    The rapid advances in mobile computing technology have the potential to change the way radiology and medicine as a whole are practiced. Several mobile computing advances have not yet found application to the practice of radiology, while others have already been applied to radiology but are not in widespread clinical use. This review addresses several areas where radiology and medicine in general may benefit from adoption of the latest mobile computing technologies and speculates on potential future applications. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  8. A Bayesian method for construction of Markov models to describe dynamics on various time-scales.

    Science.gov (United States)

    Rains, Emily K; Andersen, Hans C

    2010-10-14

    The dynamics of many biological processes of interest, such as the folding of a protein, are slow and complicated enough that a single molecular dynamics simulation trajectory of the entire process is difficult to obtain in any reasonable amount of time. Moreover, one such simulation may not be sufficient to develop an understanding of the mechanism of the process, and multiple simulations may be necessary. One approach to circumvent this computational barrier is the use of Markov state models. These models are useful because they can be constructed using data from a large number of shorter simulations instead of a single long simulation. This paper presents a new Bayesian method for the construction of Markov models from simulation data. A Markov model is specified by (τ,P,T), where τ is the mesoscopic time step, P is a partition of configuration space into mesostates, and T is an N(P)×N(P) transition rate matrix for transitions between the mesostates in one mesoscopic time step, where N(P) is the number of mesostates in P. The method presented here is different from previous Bayesian methods in several ways. (1) The method uses Bayesian analysis to determine the partition as well as the transition probabilities. (2) The method allows the construction of a Markov model for any chosen mesoscopic time-scale τ. (3) It constructs Markov models for which the diagonal elements of T are all equal to or greater than 0.5. Such a model will be called a "consistent mesoscopic Markov model" (CMMM). Such models have important advantages for providing an understanding of the dynamics on a mesoscopic time-scale. The Bayesian method uses simulation data to find a posterior probability distribution for (P,T) for any chosen τ. This distribution can be regarded as the Bayesian probability that the kinetics observed in the atomistic simulation data on the mesoscopic time-scale τ was generated by the CMMM specified by (P,T). An optimization algorithm is used to find the most

  9. Scaling Properties of Field-Induced Superdiffusion in Continuous Time Random Walks

    Science.gov (United States)

    Burioni, R.; Gradenigo, G.; Sarracino, A.; Vezzani, A.; Vulpiani, A.

    2014-10-01

    We consider a broad class of Continuous Time Random Walks (CTRW) with large fluctuations effects in space and time distributions: a random walk with trapping, describing subdiffusion in disordered and glassy materials, and a Lévy walk process, often used to model superdiffusive effects in inhomogeneous materials. We derive the scaling form of the probability distributions and the asymptotic properties of all its moments in the presence of a field by two powerful techniques, based on matching conditions and on the estimate of the contribution of rare events to power-law tails in a field.

  10. Measurement invariance of the perceived stress scale and latent mean differences across gender and time.

    Science.gov (United States)

    Barbosa-Leiker, Celestina; Kostick, Marylynne; Lei, Ming; McPherson, Sterling; Roper, Virginia; Hoekstra, Trynke; Wright, Bruce

    2013-08-01

    Measurement invariance of the 2-factor model of the Perceived Stress Scale--10-item version (Cohen & Williamson, 1988) was tested across men and women at two time points and in the combined total sample over a 2-year time frame (n = 871). Measurement invariance results indicated that the scale measured the latent factors, stress and counter-stress, equivalently in men and women and over time. With measurement invariance demonstrated, differences in latent means were tested. Results indicated that men had lower levels of frequencies of stressors, and at one time point, higher levels of counter-stress, when compared with women. When examining change in frequencies of stressors and counter-stress over 2 years with the combined male and female sample, stressors remained stable, yet counter-stress increased over time. These findings may aid in the interpretation of results when examining stressors and counter-stress in clinical samples where one would expect stress to increase, whereas positive psychological states decrease. Copyright © 2012 John Wiley & Sons, Ltd.

  11. Tracking and visualization of space-time activities for a micro-scale flu transmission study.

    Science.gov (United States)

    Qi, Feng; Du, Fei

    2013-02-07

    Infectious diseases pose increasing threats to public health with increasing population density and more and more sophisticated social networks. While efforts continue in studying the large scale dissemination of contagious diseases, individual-based activity and behaviour study benefits not only disease transmission modelling but also the control, containment, and prevention decision making at the local scale. The potential for using tracking technologies to capture detailed space-time trajectories and model individual behaviour is increasing rapidly, as technological advances enable the manufacture of small, lightweight, highly sensitive, and affordable receivers and the routine use of location-aware devices has become widespread (e.g., smart cellular phones). The use of low-cost tracking devices in medical research has also been proved effective by more and more studies. This study describes the use of tracking devices to collect data of space-time trajectories and the spatiotemporal processing of such data to facilitate micro-scale flu transmission study. We also reports preliminary findings on activity patterns related to chances of influenza infection in a pilot study. Specifically, this study employed A-GPS tracking devices to collect data on a university campus. Spatiotemporal processing was conducted for data cleaning and segmentation. Processed data was validated with traditional activity diaries. The A-GPS data set was then used for visual explorations including density surface visualization and connection analysis to examine space-time activity patterns in relation to chances of influenza infection. When compared to diary data, the segmented tracking data demonstrated to be an effective alternative and showed greater accuracies in time as well as the details of routes taken by participants. A comparison of space-time activity patterns between participants who caught seasonal influenza and those who did not revealed interesting patterns. This study

  12. Tracking and visualization of space-time activities for a micro-scale flu transmission study

    Directory of Open Access Journals (Sweden)

    Qi Feng

    2013-02-01

    Full Text Available Abstract Background Infectious diseases pose increasing threats to public health with increasing population density and more and more sophisticated social networks. While efforts continue in studying the large scale dissemination of contagious diseases, individual-based activity and behaviour study benefits not only disease transmission modelling but also the control, containment, and prevention decision making at the local scale. The potential for using tracking technologies to capture detailed space-time trajectories and model individual behaviour is increasing rapidly, as technological advances enable the manufacture of small, lightweight, highly sensitive, and affordable receivers and the routine use of location-aware devices has become widespread (e.g., smart cellular phones. The use of low-cost tracking devices in medical research has also been proved effective by more and more studies. This study describes the use of tracking devices to collect data of space-time trajectories and the spatiotemporal processing of such data to facilitate micro-scale flu transmission study. We also reports preliminary findings on activity patterns related to chances of influenza infection in a pilot study. Methods Specifically, this study employed A-GPS tracking devices to collect data on a university campus. Spatiotemporal processing was conducted for data cleaning and segmentation. Processed data was validated with traditional activity diaries. The A-GPS data set was then used for visual explorations including density surface visualization and connection analysis to examine space-time activity patterns in relation to chances of influenza infection. Results When compared to diary data, the segmented tracking data demonstrated to be an effective alternative and showed greater accuracies in time as well as the details of routes taken by participants. A comparison of space-time activity patterns between participants who caught seasonal influenza and those who

  13. Sediment Transport Time Scales and Trapping Efficiency in a Tidal River

    Science.gov (United States)

    Ralston, David K.; Geyer, W. Rockwell

    2017-11-01

    Observations and a numerical model are used to characterize sediment transport in the tidal Hudson River. A sediment budget over 11 years including major discharge events indicates the tidal fresh region traps about 40% of the sediment input from the watershed. Sediment input scales with the river discharge cubed, while seaward transport in the tidal river scales linearly, so the tidal river accumulates sediment during the highest discharge events. Sediment pulses associated with discharge events dissipate moving seaward and lag the advection speed of the river by a factor of 1.5 to 3. Idealized model simulations with a range of discharge and settling velocity were used to evaluate the trapping efficiency, transport rate, and mean age of sediment input from the watershed. The seaward transport of suspended sediment scales linearly with discharge but lags the river velocity by a factor that is linear with settling velocity. The lag factor is 30-40 times the settling velocity (mm s-1), so transport speeds vary by orders of magnitude from clay (0.01 mm s-1) to coarse silt (1 mm s-1). Deposition along the tidal river depends strongly on settling velocity, and a simple advection-reaction equation represents the loss due to settling on depositional shoals. The long-term discharge record is used to represent statistically the distribution of transport times, and time scales for settling velocities of 0.1 mm s-1 and 1 mm s-1 range from several months to several years for transport through the tidal river and several years to several decades through the estuary.

  14. Residence time distribution measurements in a pilot-scale poison tank using radiotracer technique.

    Science.gov (United States)

    Pant, H J; Goswami, Sunil; Samantray, J S; Sharma, V K; Maheshwari, N K

    2015-09-01

    Various types of systems are used to control the reactivity and shutting down of a nuclear reactor during emergency and routine shutdown operations. Injection of boron solution (borated water) into the core of a reactor is one of the commonly used methods during emergency operation. A pilot-scale poison tank was designed and fabricated to simulate injection of boron poison into the core of a reactor along with coolant water. In order to design a full-scale poison tank, it was desired to characterize flow of liquid from the tank. Residence time distribution (RTD) measurement and analysis was adopted to characterize the flow dynamics. Radiotracer technique was applied to measure RTD of aqueous phase in the tank using Bromine-82 as a radiotracer. RTD measurements were carried out with two different modes of operation of the tank and at different flow rates. In Mode-1, the radiotracer was instantaneously injected at the inlet and monitored at the outlet, whereas in Mode-2, the tank was filled with radiotracer and its concentration was measured at the outlet. From the measured RTD curves, mean residence times (MRTs), dead volume and fraction of liquid pumped in with time were determined. The treated RTD curves were modeled using suitable mathematical models. An axial dispersion model with high degree of backmixing was found suitable to describe flow when operated in Mode-1, whereas a tanks-in-series model with backmixing was found suitable to describe flow of the poison in the tank when operated in Mode-2. The results were utilized to scale-up and design a full-scale poison tank for a nuclear reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Interrelations between the perception of time and space in large-scale environments.

    Science.gov (United States)

    Riemer, Martin; Hölzl, Rupert; Kleinböhl, Dieter

    2014-04-01

    Interactions between perceived temporal and spatial properties of external stimuli (e.g. duration and size) suggest common neural mechanisms underlying the perception of time and space. This conclusion, however, lacks support from studies in large-scale environments, showing that judgements on travelled distances and associated travel times are independent from each other. Here, we used a different approach to test whether the perception of travelled distances is influenced by the perception of time. Unlike previous studies, in which temporal and spatial judgements were related to the same experience of walking, we assessed time and distance perception in analogous, but separate versions of estimation and production tasks. In estimation tasks, participants estimated the duration of a presented sound (time) or the length of a travelled distance (space), and in production tasks, participants terminated a sound after a numerically specified duration (time) or covered a numerically specified distance (space). The results show systematic overestimation of time and underestimation of travelled distance, and the latter reflecting previously reported misperceptions of visual distance. Time and distance judgements were related within individuals for production, but not for estimation tasks. These results suggest that temporal information might constitute a probabilistic cue for path integration.

  16. Using Citizen Science Observations to Model Species Distributions Over Space, Through Time, and Across Scales

    Science.gov (United States)

    Kelling, S.

    2017-12-01

    The goal of Biodiversity research is to identify, explain, and predict why a species' distribution and abundance vary through time, space, and with features of the environment. Measuring these patterns and predicting their responses to change are not exercises in curiosity. Today, they are essential tasks for understanding the profound effects that humans have on earth's natural systems, and for developing science-based environmental policies. To gain insight about species' distribution patterns requires studying natural systems at appropriate scales, yet studies of ecological processes continue to be compromised by inadequate attention to scale issues. How spatial and temporal patterns in nature change with scale often reflects fundamental laws of physics, chemistry, or biology, and we can identify such basic, governing laws only by comparing patterns over a wide range of scales. This presentation will provide several examples that integrate bird observations made by volunteers, with NASA Earth Imagery using Big Data analysis techniques to analyze the temporal patterns of bird occurrence across scales—from hemisphere-wide views of bird distributions to the impact of powerful city lights on bird migration.

  17. Radiological protection and geological disposal. The guiding principles and recommendations of the International Commission on Radiological Protection (ICRP)

    International Nuclear Information System (INIS)

    2013-06-01

    The protection of humans and the environment from the dangers of radiation is an integral part of the development of deep underground disposal for the categories of radioactive waste that will remain significantly radioactive for centuries to come and in which a high level of radioactivity is concentrated. This flyer succinctly presents the concepts and principles recommended in 2013 by the International Commission on Radiological Protection (ICRP), a gathering of the foremost specialists in radiological protection. Intended for the interested public, the flyer uses plain language. Those wishing to learn more are encouraged to consult the ICRP Publication 122. ICRP is an independent, international and non-governmental organisation with more than two hundred volunteer members from approximately thirty countries across six continents. They represent the leading scientists and policy makers in the field of radiological protection. Since 1928, the ICRP has been responsible for the International System of Radiological Protection used world-wide as the common basis for radiological protection policy, standards, legislation, regulation, guidelines, programmes, and practice. Recognizing the importance of geological disposal as a societal issue, the NEA Committees on Radioactive Waste Management and on Radiation Protection and Public Health offer this flyer jointly with the ICRP. The goal of a geological disposal facility is to contain and isolate the waste in order to protect humans and the environment for periods that are comparable with geological time scales. Geological disposal is recognized by international organisations as especially suited for high level radioactive waste or spent fuel in which a high level of radioactivity is concentrated and which will remain significantly radioactive for many thousands of years. Geological disposal may also be used for other long-lived wastes, especially when there is a similar need for long term protection. the ICRP has released

  18. Transport on intermediate time scales in flows with cat's eye patterns

    Science.gov (United States)

    Pöschke, Patrick; Sokolov, Igor M.; Zaks, Michael A.; Nepomnyashchy, Alexander A.

    2017-12-01

    We consider the advection-diffusion transport of tracers in a one-parameter family of plane periodic flows where the patterns of streamlines feature regions of confined circulation in the shape of "cat's eyes," separated by meandering jets with ballistic motion inside them. By varying the parameter, we proceed from the regular two-dimensional lattice of eddies without jets to the sinusoidally modulated shear flow without eddies. When a weak thermal noise is added, i.e., at large Péclet numbers, several intermediate time scales arise, with qualitatively and quantitatively different transport properties: depending on the parameter of the flow, the initial position of a tracer, and the aging time, motion of the tracers ranges from subdiffusive to superballistic. We report on results of extensive numerical simulations of the mean-squared displacement for different initial conditions in ordinary and aged situations. These results are compared with a theory based on a Lévy walk that describes the intermediate-time ballistic regime and gives a reasonable description of the behavior for a certain class of initial conditions. The interplay of the walk process with internal circulation dynamics in the trapped state results at intermediate time scales in nonmonotonic characteristics of aging not captured by the Lévy walk model.

  19. Nuclear magnetic resonance provides a quantitative description of protein conformational flexibility on physiologically important time scales.

    Science.gov (United States)

    Salmon, Loïc; Bouvignies, Guillaume; Markwick, Phineus; Blackledge, Martin

    2011-04-12

    A complete description of biomolecular activity requires an understanding of the nature and the role of protein conformational dynamics. In recent years, novel nuclear magnetic resonance-based techniques that provide hitherto inaccessible detail concerning biomolecular motions occurring on physiologically important time scales have emerged. Residual dipolar couplings (RDCs) provide precise information about time- and ensemble-averaged structural and dynamic processes with correlation times up to the millisecond and thereby encode key information for understanding biological activity. In this review, we present the application of two very different approaches to the quantitative description of protein motion using RDCs. The first is purely analytical, describing backbone dynamics in terms of diffusive motions of each peptide plane, using extensive statistical analysis to validate the proposed dynamic modes. The second is based on restraint-free accelerated molecular dynamics simulation, providing statistically sampled free energy-weighted ensembles that describe conformational fluctuations occurring on time scales from pico- to milliseconds, at atomic resolution. Remarkably, the results from these two approaches converge closely in terms of distribution and absolute amplitude of motions, suggesting that this kind of combination of analytical and numerical models is now capable of providing a unified description of protein conformational dynamics in solution.

  20. Time scales of relaxation dynamics during transient conditions in two-phase flow: RELAXATION DYNAMICS

    Energy Technology Data Exchange (ETDEWEB)

    Schlüter, Steffen [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis Oregon USA; Department Soil Physics, Helmholtz-Centre for Environmental Research-UFZ, Halle Germany; Berg, Steffen [Shell Global Solutions International B.V., Rijswijk Netherlands; Li, Tianyi [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis Oregon USA; Vogel, Hans-Jörg [Department Soil Physics, Helmholtz-Centre for Environmental Research-UFZ, Halle Germany; Institut für Agrar- und Ernährungswissenschaften, Martin-Luther-Universität Halle-Wittenberg, Halle Germany; Wildenschild, Dorthe [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis Oregon USA

    2017-06-01

    The relaxation dynamics toward a hydrostatic equilibrium after a change in phase saturation in porous media is governed by fluid reconfiguration at the pore scale. Little is known whether a hydrostatic equilibrium in which all interfaces come to rest is ever reached and which microscopic processes govern the time scales of relaxation. Here we apply fast synchrotron-based X-ray tomography (X-ray CT) to measure the slow relaxation dynamics of fluid interfaces in a glass bead pack after fast drainage of the sample. The relaxation of interfaces triggers internal redistribution of fluids, reduces the surface energy stored in the fluid interfaces, and relaxes the contact angle toward the equilibrium value while the fluid topology remains unchanged. The equilibration of capillary pressures occurs in two stages: (i) a quick relaxation within seconds in which most of the pressure drop that built up during drainage is dissipated, a process that is to fast to be captured with fast X-ray CT, and (ii) a slow relaxation with characteristic time scales of 1–4 h which manifests itself as a spontaneous imbibition process that is well described by the Washburn equation for capillary rise in porous media. The slow relaxation implies that a hydrostatic equilibrium is hardly ever attained in practice when conducting two-phase experiments in which a flux boundary condition is changed from flow to no-flow. Implications for experiments with pressure boundary conditions are discussed.

  1. Modified multiple time scale method for solving strongly nonlinear damped forced vibration systems

    Science.gov (United States)

    Razzak, M. A.; Alam, M. Z.; Sharif, M. N.

    2018-03-01

    In this paper, modified multiple time scale (MTS) method is employed to solve strongly nonlinear forced vibration systems. The first-order approximation is only considered in order to avoid complexicity. The formulations and the determination of the solution procedure are very easy and straightforward. The classical multiple time scale (MS) and multiple scales Lindstedt-Poincare method (MSLP) do not give desire result for the strongly damped forced vibration systems with strong damping effects. The main aim of this paper is to remove these limitations. Two examples are considered to illustrate the effectiveness and convenience of the present procedure. The approximate external frequencies and the corresponding approximate solutions are determined by the present method. The results give good coincidence with corresponding numerical solution (considered to be exact) and also provide better result than other existing results. For weak nonlinearities with weak damping effect, the absolute relative error measures (first-order approximate external frequency) in this paper is only 0.07% when amplitude A = 1.5 , while the relative error gives MSLP method is surprisingly 28.81%. Furthermore, for strong nonlinearities with strong damping effect, the absolute relative error found in this article is only 0.02%, whereas the relative error obtained by MSLP method is 24.18%. Therefore, the present method is not only valid for weakly nonlinear damped forced systems, but also gives better result for strongly nonlinear systems with both small and strong damping effect.

  2. Effective Pore-Scale Dispersion Upscaling with the Correlated Continuous Time Random Walk Approach

    Energy Technology Data Exchange (ETDEWEB)

    Le Borgne, Tanguy; Bolster, Diogo; Dentz, Marco; de Anna, Pietro; Tartakovsky, Alexandre M.

    2011-12-29

    We propose a general framework for upscaling dispersion in porous media. A key challenge of the upscaling procedure is to relate the temporal evolution of spreading to the small scale velocity field properties. The representation of the Lagrangian velocity transition process as a Markovian process in space provides a simple way to quantify complex correlation properties, i.e. non-Gaussian velocity distributions. The resulting effective transport model is a correlated CTRW. We use this framework to upscale pore scale dispersion for a periodic pore geometry. The correlated CTRW model is defined by the transit time distribution across one pore and the transition probability density quantifying the correlation between successive transit times. The latter is of central importance since it accounts for incomplete mixing at the pore throats. The predictions of the correlated CTRW model are in good agreement with the pore scale simulations over the pre-asymptotic and asymptotic regimes. We investigate the representation of this effective dispersion model in phase space (position, velocity) in a form similar to a Boltzmann transport equation.

  3. Student Perceptions of Online Radiologic Science Courses.

    Science.gov (United States)

    Papillion, Erika; Aaron, Laura

    2017-03-01

    To evaluate student perceptions of the effectiveness of online radiologic science courses by examining various learning activities and course characteristics experienced in the online learning environment. A researcher-designed electronic survey was used to obtain results from students enrolled in the clinical portion of a radiologic science program that offers online courses. The survey consisted of elements associated with demographics, experience, and perceptions related to online radiologic science courses. Surveys were sent to 35 program directors of Joint Review Committee on Education in Radiologic Technology-accredited associate and bachelor's degree programs with requests to share the survey with students. The 38 students who participated in the survey identified 4 course characteristics most important for effective online radiologic science courses: a well-organized course, timely instructor feedback, a variety of learning activities, and informative documents, such as course syllabus, calendar, and rubrics. Learner satisfaction is a successful indicator of engagement in online courses. Descriptive statistical analysis indicated that elements related to the instructor's role is one of the most important components of effectiveness in online radiologic science courses. This role includes providing an organized course with informative documents, a variety of learning activities, and timely feedback and communication. Although online courses should provide many meaningful learning activities that appeal to a wide range of learning styles, the nature of the course affects the types of learning activities used and therefore could decrease the ability to vary learning activities. ©2017 American Society of Radiologic Technologists.

  4. Bedload transport flux fluctuations over a wide range of time scales

    Science.gov (United States)

    Ma, H.; Fu, X.; Ancey, C.

    2014-12-01

    Bedload transport is a highly fluctuating process. Our previous study (Ma et al., 2014) demonstrated a three-regime relation of the variance of bedload transport flux across a wide range of sampling time scales. This study further explored the fluctuation spectrum of at-a-point bedload transport flux with different sampling times. We derived out analytical solutions of the third- and fourth-order moments of bedload transport flux, based on a physically-based formulation (Ancey et al., 2008; Ma et al., 2014). A formulation of the probability density function of bedload transport flux was constructed based on the 1st through 4th order moments. Experimental data were used to test against the solutions of both the moments and PDF. Interestingly, the higher order statistical moments were found to exhibit the three-regime pattern as well. This study contributes to a comprehensive understanding of bedload transport flux fluctuation and emphasizes its timescale-dependent features resulting from the discrete nature and correlated motion of bedload material. The correlated structures of bedload transport, such as bed forms and particle clusters, deserve to be further exploration in future studies. Keywords: bedload transport; stochastic theory; high order moment; fluctuation; time scale; PDF. Ancey, C., Davison, A. C., Bohm, T., Jodeau, M., and Frey, P. Entrainment and motion of coarse particles in a shallow water stream down a steep slope, Journal of Fluid Mechanics, 2008, 595, 83-114, doi: 10.1017/S0022112007008774. Ma, H. B., Heyman, J., Fu, X. D., Mettra, F., Ancey, C. and Parker, G. Bedload transport over a broad range of time scales: determination of three regimes of fluctuations. Journal of Geophysical Research-Earth Surface, 2014. (under review)

  5. Physics of Radiology

    CERN Document Server

    Johns, Harold Elford

    1983-01-01

    Authority, comprehensivity and a consummate manner of presentation have been hallmarks of The Physics of Radiology since it first saw publication some three decades past. This Fourth Edition adheres to that tradition but again updates the context. It thoroughly integrates ideas recently advanced and practices lately effected. Students and professionals alike will continue to view it, in essence, as the bible of radiological physics.

  6. Radiological concept of spondylodiscitis

    Energy Technology Data Exchange (ETDEWEB)

    Lingg, G.; Karbowski, A.

    1985-07-01

    The destructive discovertebral lesions of ankylosing spondylitis are discussed. Their evaluation in the literature is compared with the newer histologic and radiologic results. The X-ray findings in rheumatoid arthritis are also presented. Using radiographs from 16 of our own patients suffering from ankylosing spondylitis and 5 with rheumatoid arthritis, the analyse the radiological appearance inquestion.

  7. Medical Ethics in Radiology

    International Nuclear Information System (INIS)

    Kim, Kyung Won; Park, Jae Hyung; Yoon, Soon Ho

    2010-01-01

    According to the recent developments in radiological techniques, the role of radiology in the clinical management of patients is ever increasing and in turn, so is the importance of radiology in patient management. Thus far, there have been few open discussions about medical ethics related to radiology in Korea. Hence, concern about medical ethics as an essential field of radiology should be part of an improved resident training program and patient management. The categories of medical ethics related with radiology are ethics in the radiological management of patient, the relationship of radiologists with other medical professionals or companies, the hazard level of radiation for patients and radiologists, quality assurance of image products and modalities, research ethics, and other ethics issues related to teleradiology and fusion imaging. In order to achieve the goal of respectful progress in radiology as well as minimizing any adverse reaction from other medical professions or society, we should establish a strong basis of medical ethics through the continuous concern and self education

  8. Radiological concept of spondylodiscitis

    International Nuclear Information System (INIS)

    Lingg, G.; Karbowski, A.

    1985-01-01

    The destructive discovertebral lesions of ankylosing spondylitis are discussed. Their evaluation in the literature is compared with the newer histologic and radiologic results. The X-ray findings in rheumatoid arthritis are also presented. Using radiographs from 16 of our own patients suffering from ankylosing spondylitis and 5 with rheumatoid arthritis, the analyse the radiological appearance inquestion. (orig.) [de

  9. Characterization of radiological emergencies

    International Nuclear Information System (INIS)

    Chester, C.V.

    1986-01-01

    This paper identifies conditions that should be considered by the designers of mobile teleoperator equipment intended for service in radiological emergencies. We include a definition of radiological emergency and a taxonomy of emergencies. We will indicate the range of operating conditions that an equipment designer should consider and the type of operations that his machine might be expected to perform. 2 refs., 1 tab

  10. A reference relative time-scale as an alternative to chronological age for cohorts with long follow-up.

    Science.gov (United States)

    Hurley, Margaret Anne

    2015-01-01

    Epidemiologists have debated the appropriate time-scale for cohort survival studies; chronological age or time-on-study being two such time-scales. Importantly, assessment of risk factors may depend on the choice of time-scale. Recently, chronological or attained age has gained support but a case can be made for a 'reference relative time-scale' as an alternative which circumvents difficulties that arise with this and other scales. The reference relative time of an individual participant is the integral of a reference population hazard function between time of entry and time of exit of the individual. The objective here is to describe the reference relative time-scale, illustrate its use, make comparison with attained age by simulation and explain its relationship to modern and traditional epidemiologic methods. A comparison was made between two models; a stratified Cox model with age as the time-scale versus an un-stratified Cox model using the reference relative time-scale. The illustrative comparison used a UK cohort of cotton workers, with differing ages at entry to the study, with accrual over a time period and with long follow-up. Additionally, exponential and Weibull models were fitted since the reference relative time-scale analysis need not be restricted to the Cox model. A simulation study showed that analysis using the reference relative time-scale and analysis using chronological age had very similar power to detect a significant risk factor and both were equally unbiased. Further, the analysis using the reference relative time-scale supported fully-parametric survival modelling and allowed percentile predictions and mortality curves to be constructed. The reference relative time-scale was a viable alternative to chronological age, led to simplification of the modelling process and possessed the defined features of a good time-scale as defined in reliability theory. The reference relative time-scale has several interpretations and provides a unifying

  11. Wildfire Disturbance and Sediment Transfers over Millennial Time Scales: A Numerical Modelling Study

    Science.gov (United States)

    Martin, Y.

    2003-12-01

    Wildfire may lead to accelerated soil erosion, debris flow and shallow landsliding activity in the years following disturbance. This study focuses on coastal drainage basins in British Columbia over millennial time scales, for which accelerated rates of shallow landsliding following wildfire may be of particular significance. An algorithm for wildfire occurrence, based on lake and sediment charcoal studies undertaken in coastal British Columbia and western Washington over millennial time scales (for example, Gavin et al., 2003), is incorporated into a numerical model of sediment routing over these same time scales. A stochastic rule set for wildfire frequency, based on a Weibull distribution of fire return intervals, assigns years of fire occurrence in the model. In terms of location, south-facing aspects are assigned a 25 times greater susceptibility to wildfire than north-facing aspects. As a first-order approximation, it is supposed that loss of tree root strength resulting from stand-replacing wildfires is comparable in its effects to clearcut logging. Therefore, documentation of increased shallow landslide activity associated with logging is used to adjust landsliding transport equations for the years following wildfire disturbance. Thereafter, landsliding rates are returned to pre-disturbance values. Fire return intervals, particularly those on north-facing aspects, can be relatively long in coastal British Columbia when compared to return intervals typically found in drier mountain ranges. This study investigates the degree to which wildfire disturbance affects sediment routing and delivery to channels over millennial time scales in coastal British Columbia. Sensitivity to model parameters is evaluated. Further investigations of wildfire effects on geomorphic process operation will lead to improved understanding of natural disturbance regimes to which ecosystems adjust over both the short and long term. Such information can be used to evaluate possible

  12. Intramolecular stable isotope distributions detect plant metabolic responses on century time scales

    Science.gov (United States)

    Schleucher, Jürgen; Ehlers, Ina; Augusti, Angela; Betson, Tatiana

    2014-05-01

    Plants respond to environmental changes on a vast range of time scales, and plant gas exchanges constitute important feedback mechanisms in the global C cycle. Responses on time scales of decades to centuries are most important for climate models, for prediction of crop productivity, and for adaptation to climate change. Unfortunately, responses on these timescale are least understood. We argue that the knowledge gap on intermediate time scales is due to a lack of adequate methods that can bridge between short-term manipulative experiments (e.g. FACE) and paleo research. Manipulative experiments in plant ecophysiology give information on metabolism on time scales up to years. However, this information cannot be linked to results from retrospective studies in paleo research, because little metabolic information can be derived from paleo archives. Stable isotopes are prominent tools in plant ecophysiology, biogeochemistry and in paleo research, but in all applications to date, isotope ratios of whole molecules are measured. However, it is well established that stable isotope abundance varies among intramolecular groups of biochemical metabolites, that is each so-called "isotopomer" has a distinct abundance. This intramolecular variation carries information on metabolic regulation, which can even be traced to individual enzymes (Schleucher et al., Plant, Cell Environ 1999). Here, we apply intramolecular isotope distributions to study the metabolic response of plants to increasing atmospheric [CO2] during the past century. Greenhouse experiments show that the deuterium abundance among the two positions in the C6H2 group of photosynthetic glucose depends on [CO2] during growth. This is observed for all plants using C3 photosynthesis, and reflects the metabolic flux ratio between photorespiration and photosynthesis. Photorespiration is a major C flux that limits assimilation in C3 plants, which encompass the overwhelming fraction of terrestrial photosynthesis and the

  13. Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant

    Science.gov (United States)

    Moreno-Garcia, Isabel M.; Palacios-Garcia, Emilio J.; Pallares-Lopez, Victor; Santiago, Isabel; Gonzalez-Redondo, Miguel J.; Varo-Martinez, Marta; Real-Calvo, Rafael J.

    2016-01-01

    There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant’s components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid. PMID:27240365

  14. Model based analysis of the time scales associated to pump start-ups

    Energy Technology Data Exchange (ETDEWEB)

    Dazin, Antoine, E-mail: antoine.dazin@lille.ensam.fr [Arts et métiers ParisTech/LML Laboratory UMR CNRS 8107, 8 bld Louis XIV, 59046 Lille cedex (France); Caignaert, Guy [Arts et métiers ParisTech/LML Laboratory UMR CNRS 8107, 8 bld Louis XIV, 59046 Lille cedex (France); Dauphin-Tanguy, Geneviève, E-mail: genevieve.dauphin-tanguy@ec-lille.fr [Univ Lille Nord de France, Ecole Centrale de Lille/CRISTAL UMR CNRS 9189, BP 48, 59651, Villeneuve d’Ascq cedex F 59000 (France)

    2015-11-15

    Highlights: • A dynamic model of a hydraulic system has been built. • Three periods in a pump start-up have been identified. • The time scales of each period have been estimated. • The parameters affecting the rapidity of a pump start-up have been explored. - Abstract: The paper refers to a non dimensional analysis of the behaviour of a hydraulic system during pump fast start-ups. The system is composed of a radial flow pump and its suction and delivery pipes. It is modelled using the bond graph methodology. The prediction of the model is validated by comparison to experimental results. An analysis of the time evolution of the terms acting on the total pump pressure is proposed. It allows for a decomposition of the start-up into three consecutive periods. The time scales associated with these periods are estimated. The effects of parameters (angular acceleration, final rotation speed, pipe length and resistance) affecting the start-up rapidity are then explored.

  15. Attosecond Physics - Probing and Controlling Matter on Its Natural Time Scale

    Science.gov (United States)

    Starace, Anthony F.

    2014-03-01

    The goal of attosecond physics is to probe and control matter on its natural time scale, which for electronic motion in atoms, molecules, and solids is measured in attoseconds (= 10-18 sec). Both single attosecond pulses and attosecond pulse trains can be produced. Such pulses have opened new avenues for time-domain studies of multi-electron dynamics in atoms, molecules, and solids on their natural time scale and at dimensions shorter than molecular and even atomic dimensions. They promise a revolution in our microscopic knowledge and understanding of matter. At present the intensities of isolated attosecond pulses are very weak, so that perturbation theory is sufficient to describe the interaction of attosecond pulses with matter. Consequently, they can only be used either to initiate (``pump'') a physical process or to probe a process already under way by other means. Experimental efforts currently aim to increase the intensities of isolated attosecond pulses by orders of magnitude. Intense attosecond pulses will open the regime of nonlinear attosecond physics, in which pump/probe processes with isolated attosecond pulses will become possible and in which the broad bandwidth of isolated few-cycle attosecond pulses will enable significant control over electron motion. Work supported in part by AFOSR Award No. FA9550-12-1-0149; by DOE Office of Science, Division of Chemical Sciences, Geosciences, and Biosciences, Grant No. DE-FG03-96ER14646; and by NSF Grant No. PHY-1208059.

  16. Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant

    Directory of Open Access Journals (Sweden)

    Isabel M. Moreno-Garcia

    2016-05-01

    Full Text Available There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant’s components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid.

  17. Municipal scale scenario: Analysis of an Italian seaside town with MarkAL-TIMES

    International Nuclear Information System (INIS)

    Comodi, G.; Cioccolanti, L.; Gargiulo, M.

    2012-01-01

    This work presents three 25-year energy scenarios developed with the TIMES model generator for Pesaro, a seaside municipality in central Italy. It evaluates the effectiveness of local-scale energy policies in three sectors: households, transport, and the public sector (PS). Since the local energy demand is affected by summer tourism, seasonal consumption by holiday homes was also studied. Three scenarios were hypothesized: Business as Usual (BAU), Exemplary Public Sector (EPS), and Exemplary Municipality (EM). The EPS scenario models the exemplary role that recent European directives attribute to the PS in setting energy efficiency and technology penetration targets for itself; the EM scenario extends these targets to the household sector. In particular, the study underscores the potential of micro-cogeneration technologies in achieving local environmental targets, even though their diffusion would involve an increase in local energy consumption due to internalization of the primary energy used to produce electricity, which would no longer be wholly imported from outside municipal boundaries. The study provides information to local decision-makers by estimating the cost of implementing a number of energy policies. Finally, the study discusses the adequacy of TIMES as a tool to analyse municipal-scale scenarios. - Highlights: ► The main sectors investigated are transportation, household, and public sector. ► To account of touristic season holyday homes are modelled separately. ► Energy efficiency and renewables can help to highly reduce local consumptions. ► Micro-chp increases local consumption internalizing electricity self-production. ► Provide an insight on the adequacy of the use of TIMES at municipal scale.

  18. The Steppengrille (Gryllus spec./assimilis: selective filters and signal mismatch on two time scales.

    Directory of Open Access Journals (Sweden)

    Matti Michael Rothbart

    Full Text Available In Europe, several species of crickets are available commercially as pet food. Here we investigated the calling song and phonotactic selectivity for sound patterns on the short and long time scales for one such a cricket, Gryllus spec., available as "Gryllus assimilis", the Steppengrille, originally from Ecuador. The calling song consisted of short chirps (2-3 pulses, carrier frequency: 5.0 kHz emitted with a pulse period of 30.2 ms and chirp rate of 0.43 per second. Females exhibited high selectivity on both time scales. The preference for pulse period peaked at 33 ms which was higher then the pulse period produced by males. Two consecutive pulses per chirp at the correct pulse period were already sufficient for positive phonotaxis. The preference for the chirp pattern was limited by selectivity for small chirp duty cycles and for chirp periods between 200 ms and 500 ms. The long chirp period of the songs of males was unattractive to females. On both time scales a mismatch between the song signal of the males and the preference of females was observed. The variability of song parameters as quantified by the coefficient of variation was below 50% for all temporal measures. Hence, there was not a strong indication for directional selection on song parameters by females which could account for the observed mismatch. The divergence of the chirp period and female preference may originate from a founder effect, when the Steppengrille was cultured. Alternatively the mismatch was a result of selection pressures exerted by commercial breeders on low singing activity, to satisfy customers with softly singing crickets. In the latter case the prominent divergence between male song and female preference was the result of domestication and may serve as an example of rapid evolution of song traits in acoustic communication systems.

  19. Multi-scale simulations of droplets in generic time-dependent flows

    Science.gov (United States)

    Milan, Felix; Biferale, Luca; Sbragaglia, Mauro; Toschi, Federico

    2017-11-01

    We study the deformation and dynamics of droplets in time-dependent flows using a diffuse interface model for two immiscible fluids. The numerical simulations are at first benchmarked against analytical results of steady droplet deformation, and further extended to the more interesting case of time-dependent flows. The results of these time-dependent numerical simulations are compared against analytical models available in the literature, which assume the droplet shape to be an ellipsoid at all times, with time-dependent major and minor axis. In particular we investigate the time-dependent deformation of a confined droplet in an oscillating Couette flow for the entire capillary range until droplet break-up. In this way these multi component simulations prove to be a useful tool to establish from ``first principles'' the dynamics of droplets in complex flows involving multiple scales. European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No 642069. & European Research Council under the European Community's Seventh Framework Program, ERC Grant Agreement No 339032.

  20. EEG correlates of cognitive time scales in the Necker-Zeno model for bistable perception.

    Science.gov (United States)

    Kornmeier, J; Friedel, E; Wittmann, M; Atmanspacher, H

    2017-08-01

    The Necker-Zeno model of bistable perception provides a formal relation between the average duration of meta-stable percepts (dwell times T) of ambiguous figures and two other basic time scales (t 0 , ΔT) underlying cognitive processing. The model predicts that dwell times T covary with t 0 , ΔT or both. We tested this prediction by exploiting that observers, in particular experienced meditators, can volitionally control dwell times T. Meditators and non-meditators observed bistable Necker cubes either passively or tried to hold their current percept. The latencies of a centro-parietal event-related potential (CPP) were recorded as a physiological correlate of t 0 . Dwell times T and the CPP latencies, correlated with t 0 , differed between conditions and observer groups, while ΔT remained constant in the range predicted by the model. The covariation of CPP latencies and dwell times, as well as their quadratic functional dependence extends previous psychophysical confirmation of the Necker-Zeno model to psychophysiological measures. Copyright © 2017. Published by Elsevier Inc.

  1. Versatile synchronized real-time MEG hardware controller for large-scale fast data acquisition

    Science.gov (United States)

    Sun, Limin; Han, Menglai; Pratt, Kevin; Paulson, Douglas; Dinh, Christoph; Esch, Lorenz; Okada, Yoshio; Hämäläinen, Matti

    2017-05-01

    Versatile controllers for accurate, fast, and real-time synchronized acquisition of large-scale data are useful in many areas of science, engineering, and technology. Here, we describe the development of a controller software based on a technique called queued state machine for controlling the data acquisition (DAQ) hardware, continuously acquiring a large amount of data synchronized across a large number of channels (>400) at a fast rate (up to 20 kHz/channel) in real time, and interfacing with applications for real-time data analysis and display of electrophysiological data. This DAQ controller was developed specifically for a 384-channel pediatric whole-head magnetoencephalography (MEG) system, but its architecture is useful for wide applications. This controller running in a LabVIEW environment interfaces with microprocessors in the MEG sensor electronics to control their real-time operation. It also interfaces with a real-time MEG analysis software via transmission control protocol/internet protocol, to control the synchronous acquisition and transfer of the data in real time from >400 channels to acquisition and analysis workstations. The successful implementation of this controller for an MEG system with a large number of channels demonstrates the feasibility of employing the present architecture in several other applications.

  2. Epidemic mitigation via awareness propagation in communication networks: the role of time scales

    Science.gov (United States)

    Wang, Huijuan; Chen, Chuyi; Qu, Bo; Li, Daqing; Havlin, Shlomo

    2017-07-01

    The participation of individuals in multi-layer networks allows for feedback between network layers, opening new possibilities to mitigate epidemic spreading. For instance, the spread of a biological disease such as Ebola in a physical contact network may trigger the propagation of the information related to this disease in a communication network, e.g. an online social network. The information propagated in the communication network may increase the awareness of some individuals, resulting in them avoiding contact with their infected neighbors in the physical contact network, which might protect the population from the infection. In this work, we aim to understand how the time scale γ of the information propagation (speed that information is spread and forgotten) in the communication network relative to that of the epidemic spread (speed that an epidemic is spread and cured) in the physical contact network influences such mitigation using awareness information. We begin by proposing a model of the interaction between information propagation and epidemic spread, taking into account the relative time scale γ. We analytically derive the average fraction of infected nodes in the meta-stable state for this model (i) by developing an individual-based mean-field approximation (IBMFA) method and (ii) by extending the microscopic Markov chain approach (MMCA). We show that when the time scale γ of the information spread relative to the epidemic spread is large, our IBMFA approximation is better compared to MMCA near the epidemic threshold, whereas MMCA performs better when the prevalence of the epidemic is high. Furthermore, we find that an optimal mitigation exists that leads to a minimal fraction of infected nodes. The optimal mitigation is achieved at a non-trivial relative time scale γ, which depends on the rate at which an infected individual becomes aware. Contrary to our intuition, information spread too fast in the communication network could reduce the

  3. Hybrid approximations via second order combined dynamic derivatives on time scales

    Directory of Open Access Journals (Sweden)

    Qin Sheng

    2007-09-01

    Full Text Available This article focuses on the approximation of conventional second order derivative via the combined (diamond-$\\alpha$ dynamic derivative on time scales with necessary smoothness conditions embedded. We will show the constraints under which the second order dynamic derivative provides a consistent approximation to the conventional second derivative; the cases where the dynamic derivative approximates the derivative only via a proper modification of the existing formula; and the situations in which the dynamic derivative can never approximate consistently even with the help of available structure correction methods. Constructive error analysis will be given via asymptotic expansions for practical hybrid modeling and computational applications.

  4. Method for Hot Real-Time Analysis of Pyrolysis Vapors at Pilot Scale

    Energy Technology Data Exchange (ETDEWEB)

    Pomeroy, Marc D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-29

    Pyrolysis oils contain more than 400 compounds, up to 60% of which do not re-volatilize for subsequent chemical analysis. Vapor chemical composition is also complicated as additional condensation reactions occur during quenching and collection of the product. Due to the complexity of the pyrolysis oil, and a desire to catalytically upgrade the vapor composition before condensation, online real-time analytical techniques such as Molecular Beam Mass Spectrometry (MBMS) are of great use. However, in order to properly sample hot pyrolysis vapors at the pilot scale, many challenges must be overcome.

  5. Stability and periodicity of solutions for delay dynamic systems on time scales

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Zhu

    2014-04-01

    Full Text Available This article concerns the stability and periodicity of solutions to the delay dynamic system $$ x^{\\triangle}(t=A(t x(t + F(t, x(t, x(g(t+C(t $$ on a time scale. By the inequality technique for vectors, we obtain some stability criteria for the above system. Then, by using the Horn fixed point theorem, we present some conditions under which our system is asymptotically periodic and its periodic solution is unique. In particular, the periodic solution is positive under proper assumptions.

  6. Control of modular multilevel converters based on time-scale analysis and orthogonal functions

    DEFF Research Database (Denmark)

    Zarri, L.; Tani, A.; Mengoni, M.

    2014-01-01

    Modular multilevel converter (MMC) is a promising multilevel topology for high-voltage applications that has been developed in recent years. The control of MMCs has been analyzed in detail in many papers, showing that the converter capacitors can be kept charged and balanced by controlling...... current is still a complex task and cannot be fully tackled with traditional linear control techniques. In this paper a multiple time-scale analysis is proposed to determine an approximated model of the MMC that can be used to solve the control problem of the capacitor voltages. In addition, it is shown...

  7. A critical oscillation constant as a variable of time scales for half-linear dynamic equations

    Czech Academy of Sciences Publication Activity Database

    Řehák, Pavel

    2010-01-01

    Roč. 60, č. 2 (2010), s. 237-256 ISSN 0139-9918 R&D Projects: GA AV ČR KJB100190701 Institutional research plan: CEZ:AV0Z10190503 Keywords : dynamic equation * time scale * half-linear equation * (non)oscillation criteria * Hille-Nehari criteria * Kneser criteria * critical constant * oscillation constant * Hardy inequality Subject RIV: BA - General Mathematics Impact factor: 0.316, year: 2010 http://link.springer.com/article/10.2478%2Fs12175-010-0009-7

  8. The Sensitivity of Income Polarization - Time, length of accounting periods, equivalence scales, and income definitions

    DEFF Research Database (Denmark)

    Azhar, Hussain

    This study looks at polarization and its components’ sensitivity to assumptions about equivalence scales, income definition, ethical income distribution parameters, and the income accounting period. A representative sample of Danish individual incomes from 1984 to 2002 is utilised. Results show...... that polarization has increased over time, regardless of the applied measure, when the last part of the period is compared to the first part of the period. Primary causes being increased inequality (alienation) and faster income growth among high incomes relative to those in the middle of the distribution...

  9. Corporate social responsibility of future radiology professionals.

    Science.gov (United States)

    Collins, Sandra K; Collins, Kevin S

    2011-01-01

    Plagued by difficult economic times, many radiology managers may find themselves faced with ethical dilemmas surrounding ongoing organizational pressures to maintain high levels of productivity with restricted resources. This often times tests the level of moral resilience and corporate social consciousness of even the most experienced radiology professionals. A study was conducted to determine what Corporate Social Responsibility (CSR) orientation and viewpoint future radiology professionals may have. The results of the study indicate that these study participants may initially consider patient care more important than profit maximization. Study results indicate that these specific future radiology professionals will not need laws, legal sanctions, and intensified rules to force them to act ethically. However,they may need ongoing training as to the necessity of profit maximization if they seek the highest quality of care possible for their patients.

  10. Multi-time-scale X-ray reverberation mapping of accreting black holes

    Science.gov (United States)

    Mastroserio, Guglielmo; Ingram, Adam; van der Klis, Michiel

    2018-04-01

    Accreting black holes show characteristic reflection features in their X-ray spectrum, including an iron Kα line, resulting from hard X-ray continuum photons illuminating the accretion disc. The reverberation lag resulting from the path-length difference between direct and reflected emission provides a powerful tool to probe the innermost regions around both stellar-mass and supermassive black holes. Here, we present for the first time a reverberation mapping formalism that enables modelling of energy-dependent time lags and variability amplitude for a wide range of variability time-scales, taking the complete information of the cross-spectrum into account. We use a pivoting power-law model to account for the spectral variability of the continuum that dominates over the reverberation lags for longer time-scale variability. We use an analytic approximation to self-consistently account for the non-linear effects caused by this continuum spectral variability, which have been ignored by all previous reverberation studies. We find that ignoring these non-linear effects can bias measurements of the reverberation lags, particularly at low frequencies. Since our model is analytic, we are able to fit simultaneously for a wide range of Fourier frequencies without prohibitive computational expense. We also introduce a formalism of fitting to real and imaginary parts of our cross-spectrum statistic, which naturally avoids some mistakes/inaccuracies previously common in the literature. We perform proof-of-principle fits to Rossi X-ray Timing Explorer data of Cygnus X-1.

  11. Radiology and Global Health: The Case for a New Subspecialty

    Directory of Open Access Journals (Sweden)

    Matthew P. Lungren

    2016-08-01

    Full Text Available In high- and medium-income countries, the use of radiology has grown substantially in the last several decades. But in the developing world, access to medical imaging remains a critical problem. Unlike more structured efforts in the field of global health, interventions in global radiology have been largely unplanned, fragmented and sometimes irrelevant to the needs of the recipient society, and have not resulted in any significant progress. Access to medical imaging around the world remains dismal. There is a therefore a clear and urgent need for the radiology community to develop a vision for global radiology, beginning with defining the scope of the subject and establishing measurable goals. Agreement must be reached to declare global radiology as a bona fide subspecialty of radiology. This should soon be followed by the establishment of divisions of Global Radiology in academic radiology departments. Resident and medical students should be taught how physicians in low -income countries practice medicine without access to adequate radiology. As part of training and electives, residents and medical students should accompany global health teams to countries where the need for radiology services is great. Global scholar exchange and sabbatical opportunities should be offered to staff radiologists. Successful implementation of a unified vision of global radiology has the potential to improve access to medical imaging on a large scale. Radiology journals dedicated to the promotion of global radiology can play an important role in providing forums of discussion, analyses and sharing of field experiences. In this discussion we have attempted to make a case for assigning global radiology a subspecialty status.

  12. A Perturbed Ostrowski-Type Inequality on Time Scales for k Points for Functions Whose Second Derivatives Are Bounded

    Directory of Open Access Journals (Sweden)

    Wenbing Chen

    2008-12-01

    Full Text Available We first derive a perturbed Ostrowski-type inequality on time scales for k points for functions whose second derivatives are bounded and then unify corresponding continuous and discrete versions. We also point out some particular perturbed integral inequalities on time scales for functions whose second derivatives are bounded as special cases.

  13. A new approach to motion control of torque-constrained manipulators by using time-scaling of reference trajectories

    International Nuclear Information System (INIS)

    Moreno-Valenzuela, Javier; Orozco-Manriquez, Ernesto

    2009-01-01

    We introduce a control scheme based on using a trajectory tracking controller and an algorithm for on-line time scaling of the reference trajectories. The reference trajectories are time-scaled according to the measured tracking errors and the detected torque/acceleration saturation. Experiments are presented to illustrate the advantages of the proposed approach

  14. Time Resolved Scanning PIV measurements at fine scales in a turbulent jet

    International Nuclear Information System (INIS)

    Cheng, Y.; Torregrosa, M.M.; Villegas, A.; Diez, F.J.

    2011-01-01

    The temporal and spatial complexity of turbulent flows at intermediate and small scales has prevented the acquisition of full three-dimensional experimental data sets for validating classical turbulent theory and Direct Numerical Simulations (DNS). Experimental techniques like Particle Velocimetry, PIV, allow non-intrusive planar measurements of turbulent flows. The present work applied a Time Resolved Scanning PIV system, TRS-PIV, capable of obtaining three-dimensional two-component velocities to measure the small scales of a turbulent jet. When probing the small scales of these flows with PIV, the uncertainty of the measured turbulent properties are determined by the characteristics of the PIV system and specially the thickness of the laser sheet. A measurement of the particle distribution across the thickness of the laser sheet is proposed as a more detailed description of the PIV sheet thickness. The high temporal and spatial resolution of the TRS-PIV system allowed obtaining quasi-instantaneous volumetric vector fields at the far field of a round turbulent jet in water, albeit for a low Reynolds number of 1478 due to the speed limitations of the present camera and scanning system. Six of the nine components of the velocity gradient tensor were calculated from the velocity measurements. This allowed the visualization with near Kolmogorov-scale resolution of the velocity gradient structures in three-dimensional space. In general, these structures had a complex geometry corresponding to elongated shapes in the form of sheets and tubes. An analysis of the probability density function, pdf, of the velocity gradients calculated showed that the on-diagonal (off-diagonal) velocity gradient components were very similar to each other even for events at the tails of the pdfs, as required for homogeneous isotropy. The root mean square of the components of the velocity gradients is also calculated and their ratio of off-diagonal components to on-diagonal components

  15. Glove Perforations During Interventional Radiological Procedures

    International Nuclear Information System (INIS)

    Leena, R. V.; Shyamkumar, N. K.

    2010-01-01

    Intact surgical gloves are essential to avoid contact with blood and other body fluids. The objective of this study was to estimate the incidence of glove perforations during interventional radiological procedures. In this study, a total of 758 gloves used in 94 interventional radiological procedures were examined for perforations. Eleven perforations were encountered, only one of which was of occult type. No significant difference in the frequency of glove perforation was found between the categories with varying time duration.

  16. Variability of scaling time series in the Arctic sea-ice drift dynamics

    Directory of Open Access Journals (Sweden)

    A. Chmel

    2010-02-01

    Full Text Available The motion of an individual ice floe in the Arctic Ocean was monitored at the Russian research station North Pole 35 established on the ice pack in 2008. The ice floe speed (V was found to be correlated with wind speed (v in main features, such as the positions of maxima and minima of V and v. However, the fine structure of the V-variation cannot be explained by the wind forcing alone. There were periods of time when the floe drift was affected by the interactions of ice floes between each other or by the periodical forcing due to either the Coriolis inertia effect or the tidal activity. These data were compared with the "waiting times" statistics that are the distributions of time intervals between subsequent, sufficiently strong changes in the kinetic energy of drifting ice floe. These distributions were measured in several time windows differing in the average wind speed and wind direction, and/or in the mechanical state of the ice pack. The distribution functions N (t>τ, where N is the number of successive events of energy change separated by the time interval t that exceeds τ, constructed in different time windows demonstrate fractal or a multifractal nature of the time series during motion in the consolidated ice pack but were truly random when the ice floe drifted in the highly fragmented sea ice. The latter result shows the existence of a relationship between the long-range mechanical interactions in the pack and long-term memory (time scaling behaviour of the sea-ice motion.

  17. Confronting remote sensing product with ground base measurements across time and scale

    Science.gov (United States)

    Pourmokhtarian, A.; Dietze, M.

    2015-12-01

    Ecosystem models are essential tools in forecasting ecosystem responses to global climate change. One of the most challenging issues in ecosystem modeling is scaling while preserving landscape characteristics and minimizing loss of information, when moving from point observation to regional scale. There is a keen interest in providing accurate inputs for ecosystem models which represent ecosystem initial state conditions. Remote sensing land cover products, such as Landsat NLCD and MODIS MCD12Q1, provide extensive spatio-temporal coverage but do not capture forest composition and structure. Lidar and hyperspectral have the potential to meet this need but lack sufficient spatial and historical coverage. Forest inventory measurements provide detailed information on the landscape but in a very small footprint. Combining inventory and land cover could improve estimates of ecosystem state and characteristic across time and space. This study focuses on the challenges associated with fusing and scaling the US Forest Service FIA database and NLCD across regional scales to quantify ecosystem characteristics and reduce associated uncertainties. Across Southeast of U.S. 400 stratified random samples of 10x10 km2 landscapes were selected. Data on plant density, species, age, and DBH of trees in FIA plots within each site were extracted. Using allometry equations, the canopy cover of different plant functional types (PFTs) was estimated using a PPA-style canopy model and used to assign each inventory plot to a land cover class. Inventory and land cover were fused in a Bayesian model that adjusts the fractional coverage of inventory plots while accounting for multiple sources of uncertainty. Results were compared to estimates derived from inventory alone, land cover alone, and model spin-up alone. Our findings create a framework of data assimilation to better interpret remote sensing data using ground-based measurements.

  18. Wake losses from averaged and time-resolved power measurements at full scale wind turbines

    Science.gov (United States)

    Castellani, Francesco; Astolfi, Davide; Mana, Matteo; Becchetti, Matteo; Segalini, Antonio

    2017-05-01

    This work deals with the experimental analysis of wake losses fluctuations at full-scale wind turbines. The test case is a wind farm sited on a moderately complex terrain: 4 turbines are installed, having 2 MW of rated power each. The sources of information are the time-resolved data, as collected from the OPC server, and the 10-minutes averaged SCADA data. The objective is to compare the statistical distributions of wake losses for far and middle wakes, as can be observed through the “fast” lens of time-resolved data, for certain selected test-case time series, and through the “slow” lens of SCADA data, on a much longer time basis that allow to set the standards of the mean wake losses along the wind farm. Further, time-resolved data are used for an insight into the spectral properties of wake fluctuations, highlighting the role of the wind turbine as low-pass filter. Summarizing, the wind rose, the layout of the site and the structure of the data sets at disposal allow to study middle and far wake behavior, with a “slow” and “fast” perspective.

  19. Hawking evaporation time scale of topological black holes in anti-de Sitter spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Yen Chin, E-mail: yenchin.ong@nordita.org

    2016-02-15

    It was recently pointed out that if an absorbing boundary condition is imposed at infinity, an asymptotically anti-de Sitter Schwarzschild black hole with a spherical horizon takes only a finite amount of time to evaporate away even if its initial mass is arbitrarily large. We show that this is a rather generic property in AdS spacetimes: regardless of their horizon topologies, neutral AdS black holes in general relativity take about the same amount of time to evaporate down to the same size of order L, the AdS length scale. Our discussion focuses on the case in which the black hole has toral event horizon. A brief comment is made on the hyperbolic case, i.e. for black holes with negatively curved horizons.

  20. Dependency structure and scaling properties of financial time series are related.

    Science.gov (United States)

    Morales, Raffaello; Di Matteo, T; Aste, Tomaso

    2014-04-04

    We report evidence of a deep interplay between cross-correlations hierarchical properties and multifractality of New York Stock Exchange daily stock returns. The degree of multifractality displayed by different stocks is found to be positively correlated to their depth in the hierarchy of cross-correlations. We propose a dynamical model that reproduces this observation along with an array of other empirical properties. The structure of this model is such that the hierarchical structure of heterogeneous risks plays a crucial role in the time evolution of the correlation matrix, providing an interpretation to the mechanism behind the interplay between cross-correlation and multifractality in financial markets, where the degree of multifractality of stocks is associated to their hierarchical positioning in the cross-correlation structure. Empirical observations reported in this paper present a new perspective towards the merging of univariate multi scaling and multivariate cross-correlation properties of financial time series.

  1. Multi-time scale energy management of wind farms based on comprehensive evaluation technology

    Science.gov (United States)

    Xu, Y. P.; Huang, Y. H.; Liu, Z. J.; Wang, Y. F.; Li, Z. Y.; Guo, L.

    2017-11-01

    A novel energy management of wind farms is proposed in this paper. Firstly, a novel comprehensive evaluation system is proposed to quantify economic properties of each wind farm to make the energy management more economical and reasonable. Then, a combination of multi time-scale schedule method is proposed to develop a novel energy management. The day-ahead schedule optimizes unit commitment of thermal power generators. The intraday schedule is established to optimize power generation plan for all thermal power generating units, hydroelectric generating sets and wind power plants. At last, the power generation plan can be timely revised in the process of on-line schedule. The paper concludes with simulations conducted on a real provincial integrated energy system in northeast China. Simulation results have validated the proposed model and corresponding solving algorithms.

  2. Time-Efficient Cloning Attacks Identification in Large-Scale RFID Systems

    Directory of Open Access Journals (Sweden)

    Ju-min Zhao

    2017-01-01

    Full Text Available Radio Frequency Identification (RFID is an emerging technology for electronic labeling of objects for the purpose of automatically identifying, categorizing, locating, and tracking the objects. But in their current form RFID systems are susceptible to cloning attacks that seriously threaten RFID applications but are hard to prevent. Existing protocols aimed at detecting whether there are cloning attacks in single-reader RFID systems. In this paper, we investigate the cloning attacks identification in the multireader scenario and first propose a time-efficient protocol, called the time-efficient Cloning Attacks Identification Protocol (CAIP to identify all cloned tags in multireaders RFID systems. We evaluate the performance of CAIP through extensive simulations. The results show that CAIP can identify all the cloned tags in large-scale RFID systems fairly fast with required accuracy.

  3. Measurements of Electron Transport in Foils Irradiated with a Picosecond Time Scale Laser Pulse

    International Nuclear Information System (INIS)

    Brown, C. R. D.; Hoarty, D. J.; James, S. F.; Swatton, D.; Hughes, S. J.; Morton, J. W.; Guymer, T. M.; Hill, M. P.; Chapman, D. A.; Andrew, J. E.; Comley, A. J.; Shepherd, R.; Dunn, J.; Chen, H.; Schneider, M.; Brown, G.; Beiersdorfer, P.; Emig, J.

    2011-01-01

    The heating of solid foils by a picosecond time scale laser pulse has been studied by using x-ray emission spectroscopy. The target material was plastic foil with a buried layer of a spectroscopic tracer material. The laser pulse length was either 0.5 or 2 ps, which resulted in a laser irradiance that varied over the range 10 16 -10 19 W/cm 2 . Time-resolved measurements of the buried layer emission spectra using an ultrafast x-ray streak camera were used to infer the density and temperature conditions as a function of laser parameters and depth of the buried layer. Comparison of the data to different models of electron transport showed that they are consistent with a model of electron transport that predicts the bulk of the target heating is due to return currents.

  4. Boreal Forests Sequester Large Amounts of Mercury over Millennial Time Scales in the Absence of Wildfire.

    Science.gov (United States)

    Giesler, Reiner; Clemmensen, Karina E; Wardle, David A; Klaminder, Jonatan; Bindler, Richard

    2017-03-07

    Alterations in fire activity due to climate change and fire suppression may have profound effects on the balance between storage and release of carbon (C) and associated volatile elements. Stored soil mercury (Hg) is known to volatilize due to wildfires and this could substantially affect the land-air exchange of Hg; conversely the absence of fires and human disturbance may increase the time period over which Hg is sequestered. Here we show for a wildfire chronosequence spanning over more than 5000 years in boreal forest in northern Sweden that belowground inventories of total Hg are strongly related to soil humus C accumulation (R 2 = 0.94, p millennial time scales in the prolonged absence of fire.

  5. Multi-Time Scale Control of Demand Flexibility in Smart Distribution Networks

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu P.; Myers, Kurt S.; Bak-Jensen, Birgitte

    2017-01-01

    This paper presents a multi-timescale control strategy to deploy electric vehicle (EV) demand flexibility for simultaneously providing power balancing, grid congestion management, and economic benefits to participating actors. First, an EV charging problem is investigated from consumer, aggregator......-time adaptive control. The performance of the developed method is investigated with high EV penetration in a typical residential distribution grid. The simulation results demonstrate that HCA efficiently utilizes demand flexibility stemming from EVs to solve grid unbalancing and congestions with simultaneous......, and distribution system operator’s perspectives. A hierarchical control architecture (HCA) comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating multi-time scale controls that work from a day-ahead scheduling up to real...

  6. Impact of speculator's expectations of returns and time scales of investment on crude oil price behaviors

    International Nuclear Information System (INIS)

    He, Ling-Yun; Fan, Ying; Wei, Yi-Ming

    2009-01-01

    Based on time series of crude oil prices (daily spot), this paper analyses price fluctuation with two significant parameters τ (speculators' time scales of investment) and ε (speculators' expectations of return) by using Zipf analysis technique, specifically, by mapping τ-returns of prices into 3-alphabeted sequences (absolute frequencies) and 2-alphabeted sequences (relative frequencies), containing the fundamental information of price fluctuations. This paper empirically explores parameters and identifies various types of speculators' cognition patterns of price behavior. In order to quantify the degree of distortion, a feasible reference is proposed: an ideal speculator. Finally, this paper discusses the similarities and differences between those cognition patterns of speculators' and those of an ideal speculator. The resultant analyses identify the possible distortion of price behaviors by their patterns. (author)

  7. Short time scale variability of the BL Lacertae object OJ 287 in the near-infrared

    International Nuclear Information System (INIS)

    The results of a NIR photometric monitoring of the BL Lac object OJ 287 are presented. The standard JHK photometry shows variability of maximum amplitude of about 0.7 mag over the entire observing period of 23 months and about 0.3 mag on time intervals as short as about 3 hr. No spectral variability has been found. A fast monitoring performed in the H band, with a sampling period of about 4 min, provides evidence that variations can occur in this object on time scales of over 4 min and with an rms amplitude of 6-7 percent. These variations show slow increasing and fast decreasing trends, but no clear indication of periodicity is apparent. 30 refs

  8. Parallel Motion Simulation of Large-Scale Real-Time Crowd in a Hierarchical Environmental Model

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2012-01-01

    Full Text Available This paper presents a parallel real-time crowd simulation method based on a hierarchical environmental model. A dynamical model of the complex environment should be constructed to simulate the state transition and propagation of individual motions. By modeling of a virtual environment where virtual crowds reside, we employ different parallel methods on a topological layer, a path layer and a perceptual layer. We propose a parallel motion path matching method based on the path layer and a parallel crowd simulation method based on the perceptual layer. The large-scale real-time crowd simulation becomes possible with these methods. Numerical experiments are carried out to demonstrate the methods and results.

  9. Multi-scale modeling of Earth's gravity field in space and time

    Science.gov (United States)

    Wang, Shuo; Panet, Isabelle; Ramillien, Guillaume; Guilloux, Frédéric

    2017-05-01

    Since 2002, the GRACE mission has been providing an unprecedented view of the Earth's gravity field spatial and temporal variations. The gravity field models built from these satellite data are essential in order to study the mass redistributions within the Earth system. Often, they are modelled using spatial functions, such as spherical harmonics, averaged over a fixed time window. However, the satellite sampling naturally leads to a trade-off between the achievable spatial and temporal resolutions. In addition, the gravity variations are made of local components in space and time, reflecting the superimposition of sources. With the final aim to better estimate gravity variations related to local processes at different spatial and temporal scales, and adapt the temporal resolution of the model to its spatial resolution, we present an attempt at 4D gravity field modelling using localized functions in space and time. For that, we develop a four-dimensional wavelet basis, well localized in space and time and orthogonal in time. We then analyze the inverse problem of 4D gravity field estimation from GRACE synthetic inter-satellites potential differences along the orbit, and its regularization in a Bayesian framework, using a prior knowledge on the mass sources. We then test our approach in a simplified synthetic test setting, where only one mass source is present: hydrological mass variations over Africa during the year 2005. Applying a purely regional approach, we are able to reconstruct, regionally, the water height signal with a ≈2.5 cm accuracy at 450 km, 21 days resolution. We test the influence of the geophysical prior on this result, and conclude that it cannot explain alone the residuals between original and reconstructed mass signal. redIn contrast, an ideal test case with a perfect adequacy between the 4D basis and the synthetic data, without approximations nor regularization in solving the normal system, leads to a significantly improved reconstruction of

  10. Cross-Cultural Scaling Studies in the Development of Probabilistic Teaching Performance Criteria Anchored to Utility and Time Scales.

    Science.gov (United States)

    Pfeiffer, Mark G.; And Others

    Previous cross-cultural scaling studies are incorporated into a training and performance model of the classroom teaching job of the college professor. The model, based on German and American data, describes and sets a norm for the improvement of classroom performance. Eight teaching performance factors and a set of seven continua (six predictors…

  11. Multi-scale visual analysis of time-varying electrocorticography data via clustering of brain regions.

    Science.gov (United States)

    Murugesan, Sugeerth; Bouchard, Kristofer; Chang, Edward; Dougherty, Max; Hamann, Bernd; Weber, Gunther H

    2017-06-06

    There exists a need for effective and easy-to-use software tools supporting the analysis of complex Electrocorticography (ECoG) data. Understanding how epileptic seizures develop or identifying diagnostic indicators for neurological diseases require the in-depth analysis of neural activity data from ECoG. Such data is multi-scale and is of high spatio-temporal resolution. Comprehensive analysis of this data should be supported by interactive visual analysis methods that allow a scientist to understand functional patterns at varying levels of granularity and comprehend its time-varying behavior. We introduce a novel multi-scale visual analysis system, ECoG ClusterFlow, for the detailed exploration of ECoG data. Our system detects and visualizes dynamic high-level structures, such as communities, derived from the time-varying connectivity network. The system supports two major views: 1) an overview summarizing the evolution of clusters over time and 2) an electrode view using hierarchical glyph-based design to visualize the propagation of clusters in their spatial, anatomical context. We present case studies that were performed in collaboration with neuroscientists and neurosurgeons using simulated and recorded epileptic seizure data to demonstrate our system's effectiveness. ECoG ClusterFlow supports the comparison of spatio-temporal patterns for specific time intervals and allows a user to utilize various clustering algorithms. Neuroscientists can identify the site of seizure genesis and its spatial progression during various the stages of a seizure. Our system serves as a fast and powerful means for the generation of preliminary hypotheses that can be used as a basis for subsequent application of rigorous statistical methods, with the ultimate goal being the clinical treatment of epileptogenic zones.

  12. Sensitivity of the simulated precipitation to changes in convective relaxation time scale

    Directory of Open Access Journals (Sweden)

    S. K. Mishra

    2010-10-01

    Full Text Available The paper describes the sensitivity of the simulated precipitation to changes in convective relaxation time scale (TAU of Zhang and McFarlane (ZM cumulus parameterization, in NCAR-Community Atmosphere Model version 3 (CAM3. In the default configuration of the model, the prescribed value of TAU, a characteristic time scale with which convective available potential energy (CAPE is removed at an exponential rate by convection, is assumed to be 1 h. However, some recent observational findings suggest that, it is larger by around one order of magnitude. In order to explore the sensitivity of the model simulation to TAU, two model frameworks have been used, namely, aqua-planet and actual-planet configurations. Numerical integrations have been carried out by using different values of TAU, and its effect on simulated precipitation has been analyzed. The aqua-planet simulations reveal that when TAU increases, rate of deep convective precipitation (DCP decreases and this leads to an accumulation of convective instability in the atmosphere. Consequently, the moisture content in the lower- and mid- troposphere increases. On the other hand, the shallow convective precipitation (SCP and large-scale precipitation (LSP intensify, predominantly the SCP, and thus capping the accumulation of convective instability in the atmosphere. The total precipitation (TP remains approximately constant, but the proportion of the three components changes significantly, which in turn alters the vertical distribution of total precipitation production. The vertical structure of moist heating changes from a vertically extended profile to a bottom heavy profile, with the increase of TAU. Altitude of the maximum vertical velocity shifts from upper troposphere to lower troposphere. Similar response was seen in the actual-planet simulations. With an increase in TAU from 1 h to 8 h, there was a significant improvement in the simulation of the seasonal mean precipitation. The fraction

  13. The time scale for the transition to turbulence in a high Reynolds number, accelerated flow

    International Nuclear Information System (INIS)

    Robey, H.F.; Zhou Ye; Buckingham, A.C.; Keiter, P.; Remington, B.A.; Drake, R.P.

    2003-01-01

    An experiment is described in which an interface between materials of different density is subjected to an acceleration history consisting of a strong shock followed by a period of deceleration. The resulting flow at this interface, initiated by the deposition of strong laser radiation into the initially well characterized solid materials, is unstable to both the Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities. These experiments are of importance in their ability to access a difficult experimental regime characterized by very high energy density (high temperature and pressure) as well as large Reynolds number and Mach number. Such conditions are of interest, for example, in the study of the RM/RT induced mixing that occurs during the explosion of a core-collapse supernova. Under these experimental conditions, the flow is in the plasma state and given enough time will transition to turbulence. By analysis of the experimental data and a corresponding one-dimensional numerical simulation of the experiment, it is shown that the Reynolds number is sufficiently large (Re>10 5 ) to support a turbulent flow. An estimate of three key turbulence length scales (the Taylor and Kolmogorov microscales and a viscous diffusion scale), however, shows that the temporal duration of the present flow is insufficient to allow for the development of a turbulent inertial subrange. A methodology is described for estimating the time required under these conditions for the development of a fully turbulent flow

  14. Conflict-driven adaptive control is enhanced by integral negative emotion on a short time scale.

    Science.gov (United States)

    Yang, Qian; Pourtois, Gilles

    2018-02-05

    Negative emotion influences cognitive control, and more specifically conflict adaptation. However, discrepant results have often been reported in the literature. In this study, we broke down negative emotion into integral and incidental components using a modern motivation-based framework, and assessed whether the former could change conflict adaptation. In the first experiment, we manipulated the duration of the inter-trial-interval (ITI) to assess the actual time-scale of this effect. Integral negative emotion was induced by using loss-related feedback contingent on task performance, and measured at the subjective and physiological levels. Results showed that conflict-driven adaptive control was enhanced when integral negative emotion was elicited, compared to a control condition without changes in defensive motivation. Importantly, this effect was only found when a short, as opposed to long ITI was used, suggesting that it had a short time scale. In the second experiment, we controlled for effects of feature repetition and contingency learning, and replicated an enhanced conflict adaptation effect when integral negative emotion was elicited and a short ITI was used. We interpret these new results against a standard cognitive control framework assuming that integral negative emotion amplifies specific control signals transiently, and in turn enhances conflict adaptation.

  15. Nonlinear multidimensional scaling and visualization of earthquake clusters over space, time and feature space

    Directory of Open Access Journals (Sweden)

    W. Dzwinel

    2005-01-01

    Full Text Available We present a novel technique based on a multi-resolutional clustering and nonlinear multi-dimensional scaling of earthquake patterns to investigate observed and synthetic seismic catalogs. The observed data represent seismic activities around the Japanese islands during 1997-2003. The synthetic data were generated by numerical simulations for various cases of a heterogeneous fault governed by 3-D elastic dislocation and power-law creep. At the highest resolution, we analyze the local cluster structures in the data space of seismic events for the two types of catalogs by using an agglomerative clustering algorithm. We demonstrate that small magnitude events produce local spatio-temporal patches delineating neighboring large events. Seismic events, quantized in space and time, generate the multi-dimensional feature space characterized by the earthquake parameters. Using a non-hierarchical clustering algorithm and nonlinear multi-dimensional scaling, we explore the multitudinous earthquakes by real-time 3-D visualization and inspection of the multivariate clusters. At the spatial resolutions characteristic of the earthquake parameters, all of the ongoing seismicity both before and after the largest events accumulates to a global structure consisting of a few separate clusters in the feature space. We show that by combining the results of clustering in both low and high resolution spaces, we can recognize precursory events more precisely and unravel vital information that cannot be discerned at a single resolution.

  16. Recognizing Axionic Dark Matter by Compton and de Broglie Scale Modulation of Pulsar Timing.

    Science.gov (United States)

    De Martino, Ivan; Broadhurst, Tom; Tye, S-H Henry; Chiueh, Tzihong; Schive, Hsi-Yu; Lazkoz, Ruth

    2017-12-01

    Light axionic dark matter, motivated by string theory, is increasingly favored for the "no weakly interacting massive particle era". Galaxy formation is suppressed below a Jeans scale of ≃10^{8}  M_{⊙} by setting the axion mass to m_{B}∼10^{-22}  eV, and the large dark cores of dwarf galaxies are explained as solitons on the de Broglie scale. This is persuasive, but detection of the inherent scalar field oscillation at the Compton frequency ω_{B}=(2.5  months)^{-1}(m_{B}/10^{-22}  eV) would be definitive. By evolving the coupled Schrödinger-Poisson equation for a Bose-Einstein condensate, we predict the dark matter is fully modulated by de Broglie interference, with a dense soliton core of size ≃150  pc, at the Galactic center. The oscillating field pressure induces general relativistic time dilation in proportion to the local dark matter density and pulsars within this dense core have detectably large timing residuals of ≃400  nsec/(m_{B}/10^{-22}  eV). This is encouraging as many new pulsars should be discovered near the Galactic center with planned radio surveys. More generally, over the whole Galaxy, differences in dark matter density between pairs of pulsars imprints a pairwise Galactocentric signature that can be distinguished from an isotropic gravitational wave background.

  17. Interactive exploration of large-scale time-varying data using dynamic tracking graphs

    KAUST Repository

    Widanagamaachchi, W.

    2012-10-01

    Exploring and analyzing the temporal evolution of features in large-scale time-varying datasets is a common problem in many areas of science and engineering. One natural representation of such data is tracking graphs, i.e., constrained graph layouts that use one spatial dimension to indicate time and show the "tracks" of each feature as it evolves, merges or disappears. However, for practical data sets creating the corresponding optimal graph layouts that minimize the number of intersections can take hours to compute with existing techniques. Furthermore, the resulting graphs are often unmanageably large and complex even with an ideal layout. Finally, due to the cost of the layout, changing the feature definition, e.g. by changing an iso-value, or analyzing properly adjusted sub-graphs is infeasible. To address these challenges, this paper presents a new framework that couples hierarchical feature definitions with progressive graph layout algorithms to provide an interactive exploration of dynamically constructed tracking graphs. Our system enables users to change feature definitions on-the-fly and filter features using arbitrary attributes while providing an interactive view of the resulting tracking graphs. Furthermore, the graph display is integrated into a linked view system that provides a traditional 3D view of the current set of features and allows a cross-linked selection to enable a fully flexible spatio-temporal exploration of data. We demonstrate the utility of our approach with several large-scale scientific simulations from combustion science. © 2012 IEEE.

  18. Characterization of Microbial Fuel Cells at Microbially and Electrochemically Meaningful Time scales

    KAUST Repository

    Ren, Zhiyong

    2011-03-15

    The variable biocatalyst density in a microbial fuel cell (MFC) anode biofilm is a unique feature of MFCs relative to other electrochemical systems, yet performance characterizations of MFCs typically involve analyses at electrochemically relevant time scales that are insufficient to account for these variable biocatalyst effects. This study investigated the electrochemical performance and the development of anode biofilm architecture under different external loadings, with duplicate acetate-fed singlechamber MFCs stabilized at each resistance for microbially relevant time scales. Power density curves from these steady-state reactors generally showed comparable profiles despite the fact that anode biofilm architectures and communities varied considerably, showing that steady-state biofilm differences had little influence on electrochemical performance until the steady-state external loading was much larger than the reactor internal resistance. Filamentous bacteria were dominant on the anodes under high external resistances (1000 and 5000 Ω), while more diverse rod-shaped cells formed dense biofilms under lower resistances (10, 50, and 265 Ω). Anode charge transfer resistance decreased with decreasing fixed external resistances, but was consistently 2 orders of magnitude higher than the resistance at the cathode. Cell counting showed an inverse exponential correlation between cell numbers and external resistances. This direct link ofMFCanode biofilm evolution with external resistance and electricity production offers several operational strategies for system optimization. © 2011 American Chemical Society.

  19. Towards a Millennial Time-scale Vertical Deformation Field in Taiwan

    Science.gov (United States)

    Bordovaos, P. A.; Johnson, K. M.

    2015-12-01

    Pete Bordovalos and Kaj M. Johnson To better understand the feedbacks between erosion and deformation in Taiwan, we need constraints on the millennial time-scale vertical field. Dense GPS and leveling data sets in Taiwan provide measurements of the present-day vertical deformation field over the entire Taiwan island. However, it is unclear how much of this vertical field is transient (varies over earthquake cycle) or steady (over millennial time scale). A deformation model is required to decouple transient from steady deformation. This study takes a look at how the 82 mm/yr of convergence motion between the Eurasian plate and the Philippine Sea plate is distributed across the faults on Taiwan. We build a plate flexure model that consists of all known active faults and subduction zones cutting through an elastic plate supported by buoyancy. We use horizontal and vertical GPS data, leveling data, and geologic surface uplift rates with a Monte Carlo probabilistic inversion method to infer fault slip rates and locking depths on all faults. Using our model we examine how different fault geometries influence the estimates of distribution of slip along faults and deformation patterns.

  20. Spatial analysis of aquifer response times for radial flow processes: Nondimensional analysis and laboratory-scale tests

    Science.gov (United States)

    Jazaei, Farhad; Simpson, Matthew J.; Clement, T. Prabhakar

    2016-01-01

    A fundamental concept in groundwater hydrology is the notion of steady state, or equilibrium conditions. When a system at some initial steady state condition is perturbed by pumping, a transient cone of depression will develop and the system will approach a new steady state condition. Understanding the time scale required for the transient process to occur is of practical interest since it would help practitioners decide whether to use a steady state model or a more complicated transient model. Standard approaches to estimate the response time use simple scaling relationships which neglect spatial variations. Alternatively, others define the response time to be the amount of time taken for the difference between the transient and steady state solutions to fall below some arbitrary tolerance level. Here, we present a novel approach and use the concept of mean action time to predict aquifer response time scales in a two-dimensional radial geometry for pumping, injection and recovery processes. Our approach leads to relatively simple closed form expressions that explicitly show how the time scale depends on the hydraulic parameters and position. Furthermore, our dimensionless framework allows us to predict the response time scales for a range of applications including small scale laboratory problems and large scale field problems. Our analysis shows that the response time scales vary spatially, but are equivalent for pumping, injection and associated recovery processes. Furthermore, the time scale is independent of the pumping or injection flow rate. We test these predictions in a laboratory scale aquifer and find that our physical measurements corroborate the theoretical predictions.

  1. Marketing a Radiology Practice.

    Science.gov (United States)

    Levin, David C; Rao, Vijay M; Flanders, Adam E; Sundaram, Baskaran; Colarossi, Margaret

    2016-10-01

    In addition to being a profession, the practice of radiology is a business, and marketing is an important part of that business. There are many facets to marketing a radiology practice. The authors present a number of ideas on how to go about doing this. Some marketing methods can be directed to both patients and referring physicians. Others should be directed just to patients, while still others should be directed just to referring physicians. Aside from marketing, many of them provide value to both target audiences. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  2. Referral expectations of radiology

    International Nuclear Information System (INIS)

    Smith, W.L.; Altmaier, E.; Berberoglu, L.; Morris, K.

    1989-01-01

    The expectation of the referring physician are key to developing a successful practice in radiology. Structured interviews with 17 clinicians in both community care and academic practice documented that accuracy of the radiologic report was the single most important factor in clinician satisfaction. Data intercorrelation showed that accuracy of report correlated with frequency of referral (r = .49). Overall satisfaction of the referring physician with radiology correlated with accuracy (r = .69), patient satisfaction (r = .36), and efficiency in archiving (r = .42). These data may be weighted by departmental managers to allocate resources for improving referring physician satisfaction

  3. Using time scales to characterize phytoplankton assemblages in a deep subalpine lake during the thermal stratification period: Lake Iseo, Italy

    Science.gov (United States)

    Marti, Clelia Luisa; Imberger, Jörg; Garibaldi, Letizia; Leoni, Barbara

    2016-03-01

    A combination of field observations and 3-D hydrodynamic simulations were used to identify the phytoplankton species and to estimate the various time scales of the dominant physical and biological processes in Lake Iseo, a deep subalpine lake located in northern Italy, during a stratified period (July 2010). By ordering the rate processes time scales, we derive a phytoplankton patch categorization and growth interpretation that provides a general framework for the spatial distribution of phytoplankton concentration in Lake Iseo and illuminates the characteristics of their ecological niches. The results show that the diurnal surface layer was well mixed, received strong diurnal radiation, had low phosphorus concentrations and the phytoplankton biomass was sustained by the green alga Sphaerocystis schroeterii. The vertical mixing time scales were much shorter than horizontal mixing time scales causing a depth-uniform chlorophyll a concentration. The horizontal patch scale was determined by horizontal dispersion balancing the phytoplankton growth time scale, dictating the success of the observed green algae. The strongly stratified nutrient-rich metalimnion had mild light conditions and Diatoma elongatum and Planktothrix rubescens made up the largest proportions of the total phytoplankton biomass at the intermediate and deeper metalimnetic layers. The vertical transport time scales were much shorter than horizontal transport and vertical dispersion leading to growth niche for the observed phytoplankton. The study showed that time-scale hierarchy mandates the essential phytoplankton attributes or traits for success in a particular section of the water column and/or water body.

  4. The Use of the International Nuclear and Radiological Event Scale (INES) for Event Communication. Guidelines and Good Practices for Setting up a National Framework on the Effective Use of INES for Event Communication

    International Nuclear Information System (INIS)

    2014-10-01

    The IAEA’s International Nuclear and Radiological Event Scale (INES) was developed in 1990 by international experts convened by the IAEA and the OECD Nuclear Energy Agency with the aim of communicating the safety significance of events at nuclear installations. Since then, INES has been expanded to meet the growing need for communicating the safety significance of events giving rise to radiation risk. At present, INES is used for communicating to the public, in a consistent way, the safety significance of an event associated with sources of radiation, whether or not the event occurs at a facility. INES covers a wide spectrum of practices, including industrial uses such as gammagraphy, the use of sources of radiation in medicine, activities at nuclear power plants and research reactors, activities at spent nuclear fuel and radioactive waste management facilities, and the transport of radioactive material. INES has become a widely used tool for putting the safety significance of radiation events into proper perspective. The number of countries using INES has risen steadily over the past five years. As a result, there is a need to ensure the harmonized application of this scale worldwide. Up to now, international activities regarding INES have focused more on developing guidance on rating events than on the ways of using INES. This publication is the first to provide guidance on establishing or improving a national framework for the effective use of INES during event communication. It has been prepared on the basis of national experience with communicating events that have occurred since the introduction of INES. This publication also includes, in Annex I, lessons learned from the application of INES during and after the accident at the Fukushima Daiichi nuclear power plant, Guidance on the Use of INES in Evolving Severe Accidents

  5. Scales of Time Where the Quantum Discord Allows an Efficient Execution of the DQC1 Algorithm

    Directory of Open Access Journals (Sweden)

    M. Ávila

    2014-01-01

    Full Text Available The power of one qubit deterministic quantum processor (DQC1 (Knill and Laflamme (1998 generates a nonclassical correlation known as quantum discord. The DQC1 algorithm executes in an efficient way with a characteristic time given by τ=Tr[Un]/2n, where Un is an n qubit unitary gate. For pure states, quantum discord means entanglement while for mixed states such a quantity is more than entanglement. Quantum discord can be thought of as the mutual information between two systems. Within the quantum discord approach the role of time in an efficient evaluation of τ is discussed. It is found that the smaller the value of t/T is, where t is the time of execution of the DQC1 algorithm and T is the scale of time where the nonclassical correlations prevail, the more efficient the calculation of τ is. A Mösbauer nucleus might be a good processor of the DQC1 algorithm while a nuclear spin chain would not be efficient for the calculation of τ.

  6. Thalamic Lesions: A Radiological Review

    Science.gov (United States)

    Renard, Dimitri; Campello, Chantal; Bouly, Stephane; Le Floch, Anne; Thouvenot, Eric; Waconge, Anne; Taieb, Guillaume

    2014-01-01

    Background. Thalamic lesions are seen in a multitude of disorders including vascular diseases, metabolic disorders, inflammatory diseases, trauma, tumours, and infections. In some diseases, thalamic involvement is typical and sometimes isolated, while in other diseases thalamic lesions are observed only occasionally (often in the presence of other typical extrathalamic lesions). Summary. In this review, we will mainly discuss the MRI characteristics of thalamic lesions. Identification of the origin of the thalamic lesion depends on the exact localisation inside the thalamus, the presence of extrathalamic lesions, the signal changes on different MRI sequences, the evolution of the radiological abnormalities over time, the history and clinical state of the patient, and other radiological and nonradiological examinations. PMID:25100900

  7. Thalamic Lesions: A Radiological Review

    Directory of Open Access Journals (Sweden)

    Dimitri Renard

    2014-01-01

    Full Text Available Background. Thalamic lesions are seen in a multitude of disorders including vascular diseases, metabolic disorders, inflammatory diseases, trauma, tumours, and infections. In some diseases, thalamic involvement is typical and sometimes isolated, while in other diseases thalamic lesions are observed only occasionally (often in the presence of other typical extrathalamic lesions. Summary. In this review, we will mainly discuss the MRI characteristics of thalamic lesions. Identification of the origin of the thalamic lesion depends on the exact localisation inside the thalamus, the presence of extrathalamic lesions, the signal changes on different MRI sequences, the evolution of the radiological abnormalities over time, the history and clinical state of the patient, and other radiological and nonradiological examinations.

  8. A continuous time random walk model for Darcy-scale anomalous transport in heterogeneous porous media.

    Science.gov (United States)

    Comolli, Alessandro; Hakoun, Vivien; Dentz, Marco

    2017-04-01

    Achieving the understanding of the process of solute transport in heterogeneous porous media is of crucial importance for several environmental and social purposes, ranging from aquifers contamination and remediation, to risk assessment in nuclear waste repositories. The complexity of this aim is mainly ascribable to the heterogeneity of natural media, which can be observed at all the scales of interest, from pore scale to catchment scale. In fact, the intrinsic heterogeneity of porous media is responsible for the arising of the well-known non-Fickian footprints of transport, including heavy-tailed breakthrough curves, non-Gaussian spatial density profiles and the non-linear growth of the mean squared displacement. Several studies investigated the processes through which heterogeneity impacts the transport properties, which include local modifications to the advective-dispersive motion of solutes, mass exchanges between some mobile and immobile phases (e.g. sorption/desorption reactions or diffusion into solid matrix) and spatial correlation of the flow field. In the last decades, the continuous time random walk (CTRW) model has often been used to describe solute transport in heterogenous conditions and to quantify the impact of point heterogeneity, spatial correlation and mass transfer on the average transport properties [1]. Open issues regarding this approach are the possibility to relate measurable properties of the medium to the parameters of the model, as well as its capability to provide predictive information. In a recent work [2] the authors have shed new light on understanding the relationship between Lagrangian and Eulerian dynamics as well as on their evolution from arbitrary initial conditions. On the basis of these results, we derive a CTRW model for the description of Darcy-scale transport in d-dimensional media characterized by spatially random permeability fields. The CTRW approach models particle velocities as a spatial Markov process, which is

  9. Impacts of Land Use on Wetland Vegetation in the Eastern United States: Timing and Scale

    Science.gov (United States)

    Bernhardt, C. E.; Willard, D. A.; Townsend, P.; Brown, R.

    2004-12-01

    The timing and scale of vegetation change are dependent on the resilience of the ecosystem to land use change that alters hydrologic response and sediment transport. Using palynological methods, we examine the impacts of land use change in 2 distinct ecosystems (the subtropical Florida Everglades and the temperate Roanoke River floodplain) in the Eastern United States. Twentieth century water management strategies have modified the hydrology within the Florida Everglades resulting in varying degrees of vegetation changes depending on community type and location within the greater Everglades ecosystem. Analysis of pollen assemblages from herbaceous wetland communities such as sawgrass ridges, open water sloughs, and marl prairies, show rapid vegetation change in response to both increases and decreases in hydrology. However, evaluations of these wetland environments over longer time periods (centuries to millennia) and through natural alterations to hydroperiod (like Medieval Warm Period) demonstrated the ability of the vegetation to recover within a few decades. Tree-island communities, composed of flood-intolerant, woody vegetation, are largely resistant to decreases in hydroperiod. They are, however, less tolerant to sustained increases (greater than 5 years) in water levels, with no seasonal drying, resulting in long-term degradation. Tree-island pollen assemblages indicate rapid changes in vegetation composition when subjected to prolonged hydroperiod (essentially drowning the tree islands). Pollen assemblages from the Roanoke River floodplain provide a perspective on the impacts of colonial land clearance, altered sedimentation, and changes in flooding regimes on forested wetland vegetation. After land clearance, organic to mineral sediments covered organic floodplain soils. Palynological evidence suggests a change towards less flood tolerant communities in areas of greatest sedimentation. These results demonstrate the rapid response of wetland plant

  10. Theta-frequency resonance at the cerebellum input stage improves spike-timing on the millisecond time-scale

    Directory of Open Access Journals (Sweden)

    Daniela eGandolfi

    2013-04-01

    Full Text Available The neuronal circuits of the brain are thought to use resonance and oscillations to improve communication over specific frequency bands (Llinas, 1988; Buzsaki, 2006. However, the properties and mechanism of these phenomena in brain circuits remain largely unknown. Here we show that, at the cerebellum input stage, the granular layer generates its maximum response at 5-7 Hz both in vivo following tactile sensory stimulation of the whisker pad and in acute slices following mossy fiber-bundle stimulation. The spatial analysis of granular layer activity performed using voltage-sensitive dye (VSD imaging revealed 5-7 Hz resonance covering large granular layer areas. In single granule cells, resonance appeared as a reorganization of output spike bursts on the millisecond time-scale, such that the first spike occurred earlier and with higher temporal precision and the probability of spike generation increased. Resonance was independent from circuit inhibition, as it persisted with little variation in the presence of the GABAA receptor blocker, gabazine. However, circuit inhibition reduced the resonance area more markedly at 7 Hz. Simulations with detailed computational models suggested that resonance depended on intrinsic granule cells ionic mechanisms: specifically, Kslow (M-like and KA currents acted as resonators and the persistent Na current and NMDA current acted as amplifiers. This form of resonance may play an important role for enhancing coherent spike emission from the granular layer when theta-frequency bursts are transmitted by the cerebral cortex and peripheral sensory structures during sensory-motor processing, cognition and learning.

  11. Pediatric radiology for medical-technical radiology assistants/radiologists

    International Nuclear Information System (INIS)

    Oppelt, Birgit

    2010-01-01

    The book on pediatric radiology includes the following chapter: differences between adults and children; psycho-social aspects concerning the patient child in radiology; relevant radiation doses in radiology; help for self-help: simple phantoms for image quality estimation in pediatric radiology; general information; immobilization of the patient; pediatric features for radiological settings; traumatology; contrast agents; biomedical radiography; computerized tomography; NMR imaging; diagnostic ultrasonography; handling of stress practical recommendations; medical displays.

  12. Portrayal of radiology in a major medical television series: How does it influence the perception of radiology among patients and radiology professionals?

    International Nuclear Information System (INIS)

    Heye, T.; Merkle, E.M.; Boll, D.T.; Leyendecker, J.R.; Gupta, R.T.

    2016-01-01

    To assess how the portrayal of Radiology on medical TV shows is perceived by patients and radiology professionals. In this IRB-approved study with patient consent waived, surveys were conducted among adult patients scheduled for radiological examinations and radiology professionals. The questionnaire investigated medical TV watching habits including interest in medical TV shows, appearance of radiological examination/staff, radiology's role in diagnosis-making, and rating of the shows' accuracy in portraying radiology relative to reality. One hundred and twenty-six patients and 240 professionals (133 technologists, 107 radiologists) participated. 63.5 % patients and 63.2 % technologists rated interest in medical TV shows ≥5 (scale 1-10) versus 38.3 % of radiologists. All groups noted regular (every 2nd/3rd show) to >1/show appearance of radiological examinations in 58.5-88.2 % compared to 21.0-46.2 % for radiological staff appearance. Radiology played a role in diagnosis-making regularly to >1/show in 45.3-52.6 %. There is a positive correlation for interest in medical TV and the perception that radiology is accurately portrayed for patients (r = 0.49; P = 0.001) and technologists (r = 0.38; P = 0.001) but not for radiologists (r = 0.01). The majority of patients perceive the portrayed content as accurate. Radiologists should be aware of this cultivation effect to understand their patients' behaviour which may create false expectations towards radiological examinations and potential safety hazards. (orig.)

  13. SA Journal of Radiology

    African Journals Online (AJOL)

    SA Journal of Radiology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 2 (2005) >. Log in or Register to get access to full text downloads.

  14. SA Journal of Radiology

    African Journals Online (AJOL)

    SA Journal of Radiology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 17, No 1 (2013) >. Log in or Register to get access to full text downloads.

  15. American College of Radiology

    Science.gov (United States)

    ... 2017 Meeting & Course Calendar Where ACR Exhibits ACR Data Science Institute Structures AI Advances DSI framework to help ... Announcements Upcoming Meetings 11/16/2017 The ACR Data Science Institute™ Structures Artificial Intelligence Development to Optimize Radiology ...

  16. Radiology Architecture Project Primer.

    Science.gov (United States)

    Sze, Raymond W; Hogan, Laurie; Teshima, Satoshi; Davidson, Scott

    2017-12-19

    The rapid pace of technologic advancement and increasing expectations for patient- and family-friendly environments make it common for radiology leaders to be involved in imaging remodel and construction projects. Most radiologists and business directors lack formal training in architectural and construction processes but are expected to play significant and often leading roles in all phases of an imaging construction project. Avoidable mistakes can result in significant increased costs and scheduling delays; knowledgeable participation and communication can result in a final product that enhances staff workflow and morale and improves patient care and experience. This article presents practical guidelines for preparing for and leading a new imaging architectural and construction project. We share principles derived from the radiology and nonradiology literature and our own experience over the past decade completely remodeling a large pediatric radiology department and building a full-service outpatient imaging center. Copyright © 2017 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  17. Radiological considerations for decommissioning

    International Nuclear Information System (INIS)

    Adler, J.J.

    1993-01-01

    It has been said, by those uninitiated to decommissioning work, that radiological considerations required for decommissioning are the same as those for an operating facility. In reality, nothing could be further from the truth. The act of decommissioning can be likened to cutting off a tree limb while sitting on it. This paper discusses some of the unique radiological aspects that are associated with implementing a decommissioning health physics program. There are physical constraints that may cause major differences between a normal operational and a decommissioning health physics program. Throughout the decommissioning process, the installed equipment and services that were needed to support an operational program are constantly being removed or may already be disabled due to the age of the facility. Those affecting radiological protection programs typically would include radiation shielding, ventilation systems, breathing air supply for respiratory protection, and radiological monitoring systems

  18. Radiology and the law

    International Nuclear Information System (INIS)

    Bundy, A.L.

    1988-01-01

    This book contains 12 chapters. Some of the chapter titles are: The Law of Medical Malpractice: An Overview; The Radiologist as Defendant; The Radiologist as an Expert Witness; The Missed Diagnosis; Legalities of the Radiograph; and Angiography and Interventional Radiology

  19. Radiology capital asset management.

    Science.gov (United States)

    Wagener, G N; Pridlides, A J

    1993-01-01

    Radiology administrators are expected not only to take on the ultimate accountability for meeting the needs and challenges of present day-to-day operations, but also to plan for the future. Computer Aided Facility Management (CAFM), as a tool, enables radiology managers to obtain up-to-date data to manage their services. Using Autocad on a unix-based minicomputer as the graphical base generator and integrating information from a MUMPS-based minicomputer, the CAFM process can define areas to be studied for productivity and life cycle costs. From an analysis of radiology service, management was able to make solid judgement calls for equipment replacement and facility project renovation to effectively manage radiology resources.

  20. Empirical behavior of a world stock index from intra-day to monthly time scales

    Science.gov (United States)

    Breymann, W.; Lüthi, D. R.; Platen, E.

    2009-10-01

    Most of the papers that study the distributional and fractal properties of financial instruments focus on stock prices or foreign exchange rates. This typically leads to mixed results concerning the distributions of log-returns and some multi-fractal properties of exchange rates, stock prices, and regional indices. This paper uses a well diversified world stock index as the central object of analysis. Such index approximates the growth optimal portfolio, which is demonstrated under the benchmark approach, it is the ideal reference unit for studying basic securities. When denominating this world index in units of a given currency, one measures the movements of the currency against the entire market. This provides a least disturbed observation of the currency dynamics. In this manner, one can expect to disentangle, e.g., the superposition of the two currencies involved in an exchange rate. This benchmark approach to the empirical analysis of financial data allows us to establish remarkable stylized facts. Most important is the observation that the repeatedly documented multi-fractal appearance of financial time series is very weak and much less pronounced than the deviation of the mono-scaling properties from Brownian-motion type scaling. The generalized Hurst exponent H(2) assumes typical values between 0.55 and 0.6. Accordingly, autocorrelations of log-returns decay according to a power law, and the quadratic variation vanishes when going to vanishing observation time step size. Furthermore, one can identify the Student t distribution as the log-return distribution of a well-diversified world stock index for long time horizons when a long enough data series is used for estimation. The study of dependence properties, finally, reveals that jumps at daily horizon originate primarily in the stock market while at 5min horizon they originate in the foreign exchange market. The principal message of the empirical analysis is that there is evidence that a diffusion model