WorldWideScience

Sample records for level reference set

  1. Fluoroscopy in paediatric fractures - Setting a local diagnostic reference level

    International Nuclear Information System (INIS)

    Pillai, A.; McAuley, A.; McMurray, K.; Jain, M.

    2006-01-01

    Background: The ionizing radiations (Medical Exposure) Regulation 2000 has made it mandatory to establish diagnostic reference levels (DRLs) for all typical radiological examinations. Objectives: We attempt to provide dose data for some common fluoroscopic procedures used in orthopaedic trauma that may be used as the basis for setting DRLs for paediatric patients. Materials and methods: The dose area product (DAP) in 865 paediatric trauma examinations was analysed. Median DAP values and screening times for each procedure type along with quartile values for each range are presented. Results: In the upper limb, elbow examinations had maximum exposure with a median DAP value of 1.21 cGy cm 2 . Median DAP values for forearm and wrist examinations were 0.708 and 0.538 cGy cm 2 , respectively. In lower limb, tibia and fibula examinations had a median DAP value of 3.23 cGy cm 2 followed by ankle examinations with a median DAP of 3.10 cGy cm 2 . The rounded third quartile DAP value for each distribution can be used as a provisional DRL for the specific procedure type. (authors)

  2. Fluoroscopy-guided insertion of nasojejunal tubes in children - setting local diagnostic reference levels

    International Nuclear Information System (INIS)

    Vitta, Lavanya; Raghavan, Ashok; Sprigg, Alan; Morrell, Rachel

    2009-01-01

    Little is known about the radiation burden from fluoroscopy-guided insertions of nasojejunal tubes (NJTs) in children. There are no recommended or published standards of diagnostic reference levels (DRLs) available. To establish reference dose area product (DAP) levels for the fluoroscopy-guided insertion of nasojejunal tubes as a basis for setting DRLs for children. In addition, we wanted to assess our local practice and determine the success and complication rates associated with this procedure. Children who had NJT insertion procedures were identified retrospectively from the fluoroscopy database. The age of the child at the time of the procedure, DAP, screening time, outcome of the procedure, and any complications were recorded for each procedure. As the radiation dose depends on the size of the child, the children were assigned to three different age groups. The sample size, mean, median and third-quartile DAPs were calculated for each group. The third-quartile values were used to establish the DRLs. Of 186 procedures performed, 172 were successful on the first attempt. These were performed in a total of 43 children with 60% having multiple insertions over time. The third-quartile DAPs were as follows for each age group: 0-12 months, 2.6 cGy cm 2 ; 1-7 years, 2.45 cGy cm 2 ; >8 years, 14.6 cGy cm 2 . High DAP readings were obtained in the 0-12 months (n = 4) and >8 years (n = 2) age groups. No immediate complications were recorded. Fluoroscopy-guided insertion of NJTs is a highly successful procedure in a selected population of children and is associated with a low complication rate. The radiation dose per procedure is relatively low. (orig.)

  3. SETS reference manual

    International Nuclear Information System (INIS)

    Worrell, R.B.

    1985-05-01

    The Set Equation Transformation System (SETS) is used to achieve the symbolic manipulation of Boolean equations. Symbolic manipulation involves changing equations from their original forms into more useful forms - particularly by applying Boolean identities. The SETS program is an interpreter which reads, interprets, and executes SETS user programs. The user writes a SETS user program specifying the processing to be achieved and submits it, along with the required data, for execution by SETS. Because of the general nature of SETS, i.e., the capability to manipulate Boolean equations regardless of their origin, the program has been used for many different kinds of analysis

  4. Setting reference targets

    International Nuclear Information System (INIS)

    Ruland, R.E.

    1997-04-01

    Reference Targets are used to represent virtual quantities like the magnetic axis of a magnet or the definition of a coordinate system. To explain the function of reference targets in the sequence of the alignment process, this paper will first briefly discuss the geometry of the trajectory design space and of the surveying space, then continue with an overview of a typical alignment process. This is followed by a discussion on magnet fiducialization. While the magnetic measurement methods to determine the magnetic centerline are only listed (they will be discussed in detail in a subsequent talk), emphasis is given to the optical/mechanical methods and to the task of transferring the centerline position to reference targets

  5. Tails from previous exposures: a general problem in setting reference levels for the assessment of internal contamination

    International Nuclear Information System (INIS)

    Breuer, F.; Frittelli, L.

    1988-01-01

    Reference levels for retention and excretion are evaluated for routine and special monitoring following the intake of a fraction of ICRP annual limits (ALIs) or of a unit activity. Methodologies are also suggested for taking into account the contribution by previous intakes to excretion or retention

  6. Reference handbook: Level detectors

    International Nuclear Information System (INIS)

    1990-01-01

    The purpose of this handbook is to provide Rocky Flats personnel with the information necessary to understand level measurement and detection. Upon completion of this handbook you should be able to do the following: List three reasons for measuring level. Describe the basic operating principles of the sight glass. Demonstrate proper techniques for reading a sight glass. Describe the basic operating principles of a float level detector. Describe the basic operating principles of a bubbler level indicating system. Explain the differences between a wet and dry reference leg indicating system, and describe how each functions. This handbook is designed for use by experienced Rocky Flats operators to reinforce and improve their current knowledge level, and by entry-level operators to ensure that they possess a minimum level of fundamental knowledge. Level Detectors is applicable to many job classifications and can be used as a reference for classroom work or for self-study. Although this reference handbook is by no means all-encompassing, you will gain enough information about this subject area to assist you in contributing to the safe operation of Rocky Flats Plant

  7. ENRAF gauge reference level calculations

    Energy Technology Data Exchange (ETDEWEB)

    Huber, J.H., Fluor Daniel Hanford

    1997-02-06

    This document describes the method for calculating reference levels for Enraf Series 854 Level Detectors as installed in the tank farms. The reference level calculation for each installed level gauge is contained herein.

  8. Methodology for setting the reference levels in the measurements of the dose rate absorbed in air due to the environmental gamma radiation

    International Nuclear Information System (INIS)

    Dominguez Ley, Orlando; Capote Ferrera, Eduardo; Caveda Ramos, Celia; Alonso Abad, Dolores

    2008-01-01

    Full text: The methodology for setting the reference levels of the measurements of the gamma dose rate absorbed in the air is described. The registration level was obtained using statistical methods. To set the alarm levels, it was necessary to begin with certain affectation level, which activates the investigation operation mode when being reached. It is was necessary to transform this affectation level into values of the indicators selected to set the appearance of an alarm in the network, allowing its direct comparison and at the same time a bigger operability of this one. The affectation level was assumed as an effective dose of 1 mSv/y, which is the international dose limit for public. The conversion factor obtained in a practical way as a consequence of the Chernobyl accident was assumed, converting the value of annual effective dose into values of effective dose rate in air. These factors are the most important in our work, since the main task of the National Network of Environmental Radiological Surveillance of the Republic of Cuba is detecting accidents with a situations regional affectation, and this accident is precisely an example of pollution at this scale. The alarm level setting was based on the results obtained in the first year of the Chernobyl accident. For this purpose, some transformations were achieved. In the final results, a correction factor was introduced depending on the year season the measurement was made. It was taken into account the influence of different meteorological events on the measurement of this indicator. (author)

  9. Diagnostic reference levels in medical imaging

    International Nuclear Information System (INIS)

    Rosenstein, M.

    2001-01-01

    The paper proposes additional advice to national or local authorities and the clinical community on the application of diagnostic reference levels as a practical tool to manage radiation doses to patients in diagnostic radiology and nuclear medicine. A survey was made of the various approaches that have been taken by authoritative bodies to establish diagnostic reference levels for medical imaging tasks. There are a variety of ways to implement the idea of diagnostic reference levels, depending on the medical imaging task of interest, the national or local state of practice and the national or local preferences for technical implementation. The existing International Commission on Radiological Protection (ICRP) guidance is reviewed, the survey information is summarized, a set of unifying principles is espoused and a statement of additional advice that has been proposed to ICRP Committee 3 is presented. The proposed advice would meet a need for a unifying set of principles to provide a framework for diagnostic reference levels but would allow flexibility in their selection and use. While some illustrative examples are given, the proposed advice does not specify the specific quantities to be used, the numerical values to be set for the quantities or the technical details of how national or local authorities should implement diagnostic reference levels. (author)

  10. Swiss National Reference Levels in Fluoroscopy

    International Nuclear Information System (INIS)

    Aroua, A.; Baechler, S.; Verdun, F.R.; Rickli, H.; Trueb, Ph.R.; Vock, P.

    2006-01-01

    A nationwide survey was launched in Switzerland in order to investigate the use of fluoroscopy and to establish national reference levels (R.L.) for dose-intensive procedures particularly in interventional radiology. The 2-year investigation covered 5 radiology and 9 cardiology departments in public hospitals and private clinics, and focused on twelve types of examinations: six diagnostic and six interventional. The performance of the fluoroscopy units used in these health-care centres (image quality and dose) was assessed extensively and 1000 examinations were registered. Information on the fluoroscopy time (T), the number of frames (N), the dose-area product (D.A.P.), the difficulty of the case, the age, gender, height and weight of the patient, as well as the experience of the practitioner was provided. The whole set of data was used in relative values (to the mean values for each type of examination) to establish the distributions of T, N and the D.A.P.. From these distributions a set of R.L. values was deduced for the types of examinations investigated using the 3.-quartile method. The R.L. values found are compared to the data published in the literature. (authors)

  11. A Standardized Reference Data Set for Vertebrate Taxon Name Resolution.

    Science.gov (United States)

    Zermoglio, Paula F; Guralnick, Robert P; Wieczorek, John R

    2016-01-01

    Taxonomic names associated with digitized biocollections labels have flooded into repositories such as GBIF, iDigBio and VertNet. The names on these labels are often misspelled, out of date, or present other problems, as they were often captured only once during accessioning of specimens, or have a history of label changes without clear provenance. Before records are reliably usable in research, it is critical that these issues be addressed. However, still missing is an assessment of the scope of the problem, the effort needed to solve it, and a way to improve effectiveness of tools developed to aid the process. We present a carefully human-vetted analysis of 1000 verbatim scientific names taken at random from those published via the data aggregator VertNet, providing the first rigorously reviewed, reference validation data set. In addition to characterizing formatting problems, human vetting focused on detecting misspelling, synonymy, and the incorrect use of Darwin Core. Our results reveal a sobering view of the challenge ahead, as less than 47% of name strings were found to be currently valid. More optimistically, nearly 97% of name combinations could be resolved to a currently valid name, suggesting that computer-aided approaches may provide feasible means to improve digitized content. Finally, we associated names back to biocollections records and fit logistic models to test potential drivers of issues. A set of candidate variables (geographic region, year collected, higher-level clade, and the institutional digitally accessible data volume) and their 2-way interactions all predict the probability of records having taxon name issues, based on model selection approaches. We strongly encourage further experiments to use this reference data set as a means to compare automated or computer-aided taxon name tools for their ability to resolve and improve the existing wealth of legacy data.

  12. A Standardized Reference Data Set for Vertebrate Taxon Name Resolution.

    Directory of Open Access Journals (Sweden)

    Paula F Zermoglio

    Full Text Available Taxonomic names associated with digitized biocollections labels have flooded into repositories such as GBIF, iDigBio and VertNet. The names on these labels are often misspelled, out of date, or present other problems, as they were often captured only once during accessioning of specimens, or have a history of label changes without clear provenance. Before records are reliably usable in research, it is critical that these issues be addressed. However, still missing is an assessment of the scope of the problem, the effort needed to solve it, and a way to improve effectiveness of tools developed to aid the process. We present a carefully human-vetted analysis of 1000 verbatim scientific names taken at random from those published via the data aggregator VertNet, providing the first rigorously reviewed, reference validation data set. In addition to characterizing formatting problems, human vetting focused on detecting misspelling, synonymy, and the incorrect use of Darwin Core. Our results reveal a sobering view of the challenge ahead, as less than 47% of name strings were found to be currently valid. More optimistically, nearly 97% of name combinations could be resolved to a currently valid name, suggesting that computer-aided approaches may provide feasible means to improve digitized content. Finally, we associated names back to biocollections records and fit logistic models to test potential drivers of issues. A set of candidate variables (geographic region, year collected, higher-level clade, and the institutional digitally accessible data volume and their 2-way interactions all predict the probability of records having taxon name issues, based on model selection approaches. We strongly encourage further experiments to use this reference data set as a means to compare automated or computer-aided taxon name tools for their ability to resolve and improve the existing wealth of legacy data.

  13. Establishing diagnostic reference levels in digital radiology

    International Nuclear Information System (INIS)

    Bana, Remy Wilson

    2016-04-01

    Medical application of radiation has gained wider study since diagnostic radiology plays a very important role in modern medicine. The need of the service seems to increase since the invention of digital radiology as a new technology that promises greater accuracy while minimizing patient dose. However, it is not exempted in the harmonization of doses delivered to the patient undergoing same radiologic examination in different institutions either regional or nationwide. The objective of this project was to review the establishment of Diagnostic Reference Levels (DRLs) in digital radiology at National level with the aim to reduce patient dose while maintaining appropriate image quality. A general discussion on digital radiology has been presented focusing on the optimization of patient dose as well as dosimetric quantities used for the establishment of DRLs. Recommendations have been provided for Rwanda to initiate steps to establish National Diagnostic Reference Levels for common procedures in digital radiology. (au)

  14. On reinitializing level set functions

    Science.gov (United States)

    Min, Chohong

    2010-04-01

    In this paper, we consider reinitializing level functions through equation ϕt+sgn(ϕ0)(‖∇ϕ‖-1)=0[16]. The method of Russo and Smereka [11] is taken in the spatial discretization of the equation. The spatial discretization is, simply speaking, the second order ENO finite difference with subcell resolution near the interface. Our main interest is on the temporal discretization of the equation. We compare the three temporal discretizations: the second order Runge-Kutta method, the forward Euler method, and a Gauss-Seidel iteration of the forward Euler method. The fact that the time in the equation is fictitious makes a hypothesis that all the temporal discretizations result in the same result in their stationary states. The fact that the absolute stability region of the forward Euler method is not wide enough to include all the eigenvalues of the linearized semi-discrete system of the second order ENO spatial discretization makes another hypothesis that the forward Euler temporal discretization should invoke numerical instability. Our results in this paper contradict both the hypotheses. The Runge-Kutta and Gauss-Seidel methods obtain the second order accuracy, and the forward Euler method converges with order between one and two. Examining all their properties, we conclude that the Gauss-Seidel method is the best among the three. Compared to the Runge-Kutta, it is twice faster and requires memory two times less with the same accuracy.

  15. Study on the setting of Reference Chinese man

    International Nuclear Information System (INIS)

    Wang Jixian; Chen Rusong

    1998-01-01

    The procedures for internal and external dose estimation, the calculation of authorized limits and derived reference levels, and the development of phantoms in the field of radiation protection are based on values for the ICRP Reference Man. Many differences exist between Asians, Europeans and North Americans with respect to race, customs and the pattern of food consumption. The neglect of these differences in the parameters used may lead to errors in dose assessment and health effect prognosis. research described in this paper was conducted to obtain reference values for the Chinese population or other Asian countries which might have major demographic contribution of Chinese. Based on the agreements reached in the Project Formulation Meeting ''Compilation of Anatomical, Physiological and Metabolic Characteristics for a Reference Asian Man'', the measurement of physique, organ mass and the food consumption were given the first priority for the first phase of the project. (author)

  16. Reference Value Advisor: a new freeware set of macroinstructions to calculate reference intervals with Microsoft Excel.

    Science.gov (United States)

    Geffré, Anne; Concordet, Didier; Braun, Jean-Pierre; Trumel, Catherine

    2011-03-01

    International recommendations for determination of reference intervals have been recently updated, especially for small reference sample groups, and use of the robust method and Box-Cox transformation is now recommended. Unfortunately, these methods are not included in most software programs used for data analysis by clinical laboratories. We have created a set of macroinstructions, named Reference Value Advisor, for use in Microsoft Excel to calculate reference limits applying different methods. For any series of data, Reference Value Advisor calculates reference limits (with 90% confidence intervals [CI]) using a nonparametric method when n≥40 and by parametric and robust methods from native and Box-Cox transformed values; tests normality of distributions using the Anderson-Darling test and outliers using Tukey and Dixon-Reed tests; displays the distribution of values in dot plots and histograms and constructs Q-Q plots for visual inspection of normality; and provides minimal guidelines in the form of comments based on international recommendations. The critical steps in determination of reference intervals are correct selection of as many reference individuals as possible and analysis of specimens in controlled preanalytical and analytical conditions. Computing tools cannot compensate for flaws in selection and size of the reference sample group and handling and analysis of samples. However, if those steps are performed properly, Reference Value Advisor, available as freeware at http://www.biostat.envt.fr/spip/spip.php?article63, permits rapid assessment and comparison of results calculated using different methods, including currently unavailable methods. This allows for selection of the most appropriate method, especially as the program provides the CI of limits. It should be useful in veterinary clinical pathology when only small reference sample groups are available. ©2011 American Society for Veterinary Clinical Pathology.

  17. Fast Sparse Level Sets on Graphics Hardware

    NARCIS (Netherlands)

    Jalba, Andrei C.; Laan, Wladimir J. van der; Roerdink, Jos B.T.M.

    The level-set method is one of the most popular techniques for capturing and tracking deformable interfaces. Although level sets have demonstrated great potential in visualization and computer graphics applications, such as surface editing and physically based modeling, their use for interactive

  18. Patient dose with quality image under diagnostic reference levels

    International Nuclear Information System (INIS)

    Akula, Suresh Kumar; Singh, Gurvinder; Chougule, Arun

    2016-01-01

    Need to set Diagnostic Reference Level (DRL) for locations for all diagnostic procedures in local as compared to National. The review of DRL's should compare local with national or referenced averages and a note made of any significant variances to these averages and the justification for it. To survey and asses radiation doses to patient and reduce the redundancy in patient imaging to maintain DRLs

  19. Guidance document for setting an Acute Reference Dose in Dutch national pesticide evaluations

    NARCIS (Netherlands)

    Raaij MTM van; CSR

    2001-01-01

    This report describes a proposal for the procedures for setting an Acute Reference Dose (ARfD) for pesticides evaluated in the Netherlands. This deals with both evaluations on the national level (on behalf of the Dutch Board for the Authorisation of Pesticides (CTB)) and evaluations at the European

  20. Complement Set Reference after Implicitly Small Quantities: An Event-Related Potentials Study

    Science.gov (United States)

    Ingram, Joanne; Ferguson, Heather J.

    2018-01-01

    An anaphoric reference to the complement-set is a reference to the set that does not fulfil the predicate of the preceding sentence. Preferred reference to the complement-set has been found in eye movements when a character's implicit desire for a high amount has been denied using a negative emotion. We recorded event-related potentials to examine…

  1. Setting the standard: The IAEA safety standards set the global reference

    International Nuclear Information System (INIS)

    Williams, L.

    2003-01-01

    For the IAEA, setting and promoting standards for nuclear radiation, waste, and transport safety have been priorities from the start, rooted in the Agency's 1957 Statute. Today, a corpus of international standards are in place that national regulators and industries in many countries are applying, and more are being encouraged and assisted to follow them. Considerable work is done to keep safety standards updated and authoritative. They cover five main areas: the safety of nuclear facilities; radiation protection and safety of radiation sources; safe management of radioactive waste; safe transport of radioactive material; and thematic safety areas, such as emergency preparedness or legal infrastructures. Overall, the safety standards reflect an international consensus on what constitutes a high level of safety for protecting people and the environment. All IAEA Member States can nominate experts for the Agency standards committees and provide comments on draft standards. Through this ongoing cycle of review and feedback, the standards are refined, updated, and extended where needed

  2. Determination of carbon-14 in environmental level, solid reference materials

    Energy Technology Data Exchange (ETDEWEB)

    Blowers, Paul, E-mail: paul.blowers@cefas.co.uk [Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT (United Kingdom); Caborn, Jane, E-mail: jane.a.caborn@nnl.co.uk [NNL, Springfields, Salwick, Preston, Lancashire, PR4 0XJ (United Kingdom); Dell, Tony [Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, KT15 3NB (United Kingdom); Gingell, Terry [DSTL, Radiation Protection Services, Crescent Road, Alverstoke, Gosport, Hants, PO12 2DL (United Kingdom); Harms, Arvic [National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW (United Kingdom); Long, Stephanie [Radiological Protection Institute of Ireland, 3 Clonskeagh Square, Clonskeagh Road, Dublin 14, Ireland (United Kingdom); Sleep, Darren [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP (United Kingdom); Stewart, Charlie [UKAEA (Waste Management Group), Chemical Support Services, D1310/14, Dounreay, Thurso, Caithness, KW14 7TZ (United Kingdom); Walker, Jill [Radiocarbon Dating, The Old Stables, East Lockinge, Wantage, Oxon OX12 8QY (United Kingdom); Warwick, Phil E. [GAU-Radioanalytical, National Oceanography Centre Southampton, European Way, Southampton, SO14 3ZH (United Kingdom)

    2011-10-15

    An intercomparison exercise to determine the {sup 14}C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection. The results of the study show that all techniques are capable of successfully analysing {sup 14}C in environmental level materials, however, a shortage of certified environmental reference materials exists. The suitability of the IAEA reference materials and other material for use as reference materials was also assessed.

  3. Determination of carbon-14 in environmental level, solid reference materials

    International Nuclear Information System (INIS)

    Blowers, Paul; Caborn, Jane; Dell, Tony; Gingell, Terry; Harms, Arvic; Long, Stephanie; Sleep, Darren; Stewart, Charlie; Walker, Jill; Warwick, Phil E.

    2011-01-01

    An intercomparison exercise to determine the 14 C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection. The results of the study show that all techniques are capable of successfully analysing 14 C in environmental level materials, however, a shortage of certified environmental reference materials exists. The suitability of the IAEA reference materials and other material for use as reference materials was also assessed.

  4. Reference hearing threshold levels for short duration signals

    DEFF Research Database (Denmark)

    Poulsen, Torben; Legarth, Søren Vase

    2008-01-01

    for the determination of reference hearing threshold levels. The results are given as peak-to-peak equivalent threshold sound pressure levels (peETSPL). The results are in good agreement with other sparse results from literature and are part of the basis for the ISO 389-6 standard from 2007....

  5. Evolution of diagnostic reference levels in Spanish intraoral radiology

    International Nuclear Information System (INIS)

    Alcaraz, M.; Velasco, F.; Martinez-Beneyto, Y.; Alcaraz-Saura, M.; Velasco, E.; Achel, G. D.; Canteras, M.

    2008-01-01

    A total of 16 175 official reports of quality assurance on dental radiodiagnostic surgeries from 16 Spanish autonomous regions compiled during 2002-09 were studied to determine the evolution of diagnostic reference levels (DRLs) for obtaining a diagnostic image in the normal conditions of clinical practice in Spanish dental clinics. A DRL of 3.1 mGy was set in 2009, which represents a 35.4 % decrease compared with the dose determined in 2002 (4.8 mGy). During the same period, the mean dose fell by only 17.2 %. The DRL recommended by the European Union in 2004 for intraoral radiology is 4 mGy, and this study shows that 83.4 % of the installations used a dose below this. Of the installations using indirect or direct digital systems 1.1 and 1.2 %, respectively, used doses higher than those recommended, while 14.2 % of those using radiographic film exceeded this limit. (authors)

  6. Practical considerations in the development and application of reference levels

    International Nuclear Information System (INIS)

    Selby, J. M.; Kennedy, W. E. Jr.; Swinth, K. L.; Gilbert, R. O.; Soldat, J. K.

    1988-05-01

    Radiological exposures to the public during an accident that releases radioactive materials to the environment occur initially through the air pathway, secondly through a water pathway, and finally, through the food chain. From these exposure pathways, reference levels of radionuclides must be applied to limit public radiation doses. Such reference levels are difficult to develop and apply, particularly if the contaminants are transuranic elements such as plutonium. The reference level must be related to a resultant theoretical dose to the public through generic calculations. However, to permit rapid decisions after an accident, the reference levels need to be related to conditions or media in the environment that can be directly measured. They must also be tied to specific countermeasures such as sheltering, evacuation, or interdiction of drinking water or food supplies. This paper discusses the practical considerations in the development and application of reference levels for transuranic in the environment and the present capability to rapidly detect and quantify their concentrations following accidental contamination events. 16 refs., 3 tabs

  7. An N+3 Technology Level Reference Propulsion System

    Science.gov (United States)

    Jones, Scott M.; Haller, William J.; Tong, Michael To-Hing

    2017-01-01

    An N+3 technology level engine, suitable as a propulsion system for an advanced single-aisle transport, was developed as a reference cycle for use in technology assessment and decision-making efforts. This reference engine serves three main purposes: it provides thermodynamic quantities at each major engine station, it provides overall propulsion system performance data for vehicle designers to use in their analyses, and it can be used for comparison against other proposed N+3 technology-level propulsion systems on an equal basis. This reference cycle is meant to represent the expected capability of gas turbine engines in the N+3 timeframe given reasonable extrapolations of technology improvements and the ability to take full advantage of those improvements.

  8. Establishment of local Diagnostic Reference Levels (DRLs) for ...

    African Journals Online (AJOL)

    Diagnostic reference levels (DRLs) is an essential optimization tool in radiography and radiological sciences. The objective of the study is to establish DRL for radiography examinations in north eastern Nigeria. A Prospective cross- sectional study conducted in two university teaching hospitals in north eastern Nigeria.

  9. Setting the stage for master's level success

    Science.gov (United States)

    Roberts, Donna

    Comprehensive reading, writing, research, and study skills play a critical role in a graduate student's success and ability to contribute to a field of study effectively. The literature indicated a need to support graduate student success in the areas of mentoring, navigation, as well as research and writing. The purpose of this two-phased mixed methods explanatory study was to examine factors that characterize student success at the Master's level in the fields of education, sociology and social work. The study was grounded in a transformational learning framework which focused on three levels of learning: technical knowledge, practical or communicative knowledge, and emancipatory knowledge. The study included two data collection points. Phase one consisted of a Master's Level Success questionnaire that was sent via Qualtrics to graduate level students at three colleges and universities in the Central Valley of California: a California State University campus, a University of California campus, and a private college campus. The results of the chi-square indicated that seven questionnaire items were significant with p values less than .05. Phase two in the data collection included semi-structured interview questions that resulted in three themes emerged using Dedoose software: (1) the need for more language and writing support at the Master's level, (2) the need for mentoring, especially for second-language learners, and (3) utilizing the strong influence of faculty in student success. It is recommended that institutions continually assess and strengthen their programs to meet the full range of learners and to support students to degree completion.

  10. A set of 4D pediatric XCAT reference phantoms for multimodality research

    International Nuclear Information System (INIS)

    Norris, Hannah; Zhang, Yakun; Bond, Jason; Sturgeon, Gregory M.; Samei, E.; Segars, W. P.; Minhas, Anum; Frush, D.; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.

    2014-01-01

    Purpose: The authors previously developed an adult population of 4D extended cardiac-torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female anatomies at ages of newborn, 1, 5, 10, and 15 years. These models will serve as the foundation from which the authors will create a vast population of pediatric phantoms for optimizing pediatric CT imaging protocols. Methods: Each phantom was based on a unique set of CT data from a normal patient obtained from the Duke University database. The datasets were selected to best match the reference values for height and weight for the different ages and genders according to ICRP Publication 89. The major organs and structures were segmented from the CT data and used to create an initial pediatric model defined using nonuniform rational B-spline surfaces. The CT data covered the entire torso and part of the head. To complete the body, the authors manually added on the top of the head and the arms and legs using scaled versions of the XCAT adult models or additional models created from cadaver data. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from a template XCAT phantom (male or female 50th percentile adult) to the target pediatric model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. The masses of the organs in each phantom were matched to the reference values given in ICRP Publication 89. The new reference models were checked for anatomical accuracy via visual inspection. Results: The authors created a set of ten pediatric reference phantoms that have the same level of detail and functionality as the original XCAT phantom adults. Each consists of thousands of anatomical structures and includes parameterized models

  11. A set of 4D pediatric XCAT reference phantoms for multimodality research

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Hannah, E-mail: Hannah.norris@duke.edu; Zhang, Yakun; Bond, Jason; Sturgeon, Gregory M.; Samei, E.; Segars, W. P. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Minhas, Anum; Frush, D. [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I. [Center for Imaging Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2014-03-15

    Purpose: The authors previously developed an adult population of 4D extended cardiac-torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female anatomies at ages of newborn, 1, 5, 10, and 15 years. These models will serve as the foundation from which the authors will create a vast population of pediatric phantoms for optimizing pediatric CT imaging protocols. Methods: Each phantom was based on a unique set of CT data from a normal patient obtained from the Duke University database. The datasets were selected to best match the reference values for height and weight for the different ages and genders according to ICRP Publication 89. The major organs and structures were segmented from the CT data and used to create an initial pediatric model defined using nonuniform rational B-spline surfaces. The CT data covered the entire torso and part of the head. To complete the body, the authors manually added on the top of the head and the arms and legs using scaled versions of the XCAT adult models or additional models created from cadaver data. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from a template XCAT phantom (male or female 50th percentile adult) to the target pediatric model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. The masses of the organs in each phantom were matched to the reference values given in ICRP Publication 89. The new reference models were checked for anatomical accuracy via visual inspection. Results: The authors created a set of ten pediatric reference phantoms that have the same level of detail and functionality as the original XCAT phantom adults. Each consists of thousands of anatomical structures and includes parameterized models

  12. Establishing a reference range for triiodothyronine levels in preterm infants.

    Science.gov (United States)

    Oh, Ki Won; Koo, Mi Sung; Park, Hye Won; Chung, Mi Lim; Kim, Min-ho; Lim, Gina

    2014-10-01

    Thyroid dysfunction affects clinical complications in preterm infants and older children. However, thyroid hormone replacement in preterm infants has no proven benefits, possibly owing to the lack of an appropriate reference range for thyroid hormone levels. We aimed to establish a reference range for triiodothyronine (T3) levels at 1-month postnatal age (PNA) in preterm infants. This retrospective study included preterm infants born at a tertiary referral neonatal center at gestational age (GA)<35 weeks with no apparent thyroid dysfunction, for 6 consecutive years, with follow-up from PNA 2 weeks to 16 weeks. Using thyroid function tests (TFT), the relationships between T3 levels and thyrotropin (TSH) and free thyroxine (fT4) levels, birth weight, GA, postmenstrual age (PMA), and PNA were examined. The conversion trend for fT4 to T3 was analyzed using the T3/fT4 ratio. Overall, 464 TFTs from 266 infants were analyzed, after excluding 65 infants with thyroid dysfunction. T3 levels increased with fT4 levels, birth weight, GA, PMA, and PNA but not with TSH levels. The T3/fT4 ratio also increased with GA, PNA, and PMA. The average T3 level at 1 month PNA was 72.56 ± 27.83 ng/dL, with significant stratifications by GA. Relatively low T3 and fT4 levels in preterm infants were considered normal, with T3 levels and conversion trends increasing with GA, PMA, and PNA. Further studies are required to confirm the role of the present reference range in thyroid hormone replacement therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Reference dose levels for dental panoramic radiography in Anyang City

    International Nuclear Information System (INIS)

    Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja; Lee, Jae Seo; Kim, Young Hee

    2009-01-01

    To measure dose-width product (DWP) values used for dental panoramic radiography in Anyang city, Korea. Thirty-six panoramic dental radiographic sets (17 analogue panoramic sets and 19 digital panoramic sets) in 36 dental clinics in Anyang city were included in the study. Each patient's panoramic exposure parameters were simulated and the panoramic radiation doses were measured at the secondary collimator using a Mult-O-Meter (Unfors Instruments, Billdal, Sweden) at each dental clinic during 2006. The third quartile DWP was determined from 310 surface dose measurements on adult. The third quartile DWP for adult panoramic radiograph was 106.7 mGy mm. For analogue and digital panoramic radiograph, 3/4 DWP were 116.8 mGy mm and 72 mGy mm respectively. The overall third quartile DWP of panoramic radiography was 106.7 mGy mm. The measured 3/4 DWPs were higher than the 3/4 DWP of 65 mGy mm recommended by NRPB. Dentists who are operating above the reference dose should lower their panoramic exposure doses below the recommended reference value by changing the exposure parameters and/or their panoramic equipment.

  14. Reference dose levels for dental periapical radiography in Chonnam Province

    International Nuclear Information System (INIS)

    Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja; Lee, Jae Seo; Kim, Young Hee

    2009-01-01

    To establish reference doses of periapical radiography in Chonnam Province, Korea. The target-skin distances were measured for dental patient's 1235 exposures including 345 mandibular molar areas. Each periapical radiation exposure was simulated with exactly the same patients exposure parameters and the simulated radiation doses were measured utilizing Mult-O-Meter (Unfors Instruments, Billadal, Sweden). The measurements were done in 44 dental clinics with 49 dental x-ray sets in Chonnam Province for one or two weeks at each dental clinic during year 2006. The third quartile patient surface doses were 2.8 mGy for overall periapical exposures and 3.2 mGy for periapical mandibular molar exposures. The third quartile patient surface doses in Chonnam Province can be used as a guide to accepted clinical practice to reduce patient radiation exposure for the surveyed reference doses were below the recommended dental periapical radiography dose of 7 mGy by IAEA.

  15. Reference dose levels for dental periapical radiography in Chonnam Province

    Energy Technology Data Exchange (ETDEWEB)

    Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja [Department of Oral and Maxillofacial Radiology, College of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju (Korea, Republic of); Lee, Jae Seo [Department of Oral and Maxillofacial Radiology, Chonnan National University Hospital, Gwangju (Korea, Republic of); Kim, Young Hee [Department of Oral and Maxillofacial Radiology, Hallym University Sacred Heart Hospital, Chuncheon (Korea, Republic of)

    2009-12-15

    To establish reference doses of periapical radiography in Chonnam Province, Korea. The target-skin distances were measured for dental patient's 1235 exposures including 345 mandibular molar areas. Each periapical radiation exposure was simulated with exactly the same patients exposure parameters and the simulated radiation doses were measured utilizing Mult-O-Meter (Unfors Instruments, Billadal, Sweden). The measurements were done in 44 dental clinics with 49 dental x-ray sets in Chonnam Province for one or two weeks at each dental clinic during year 2006. The third quartile patient surface doses were 2.8 mGy for overall periapical exposures and 3.2 mGy for periapical mandibular molar exposures. The third quartile patient surface doses in Chonnam Province can be used as a guide to accepted clinical practice to reduce patient radiation exposure for the surveyed reference doses were below the recommended dental periapical radiography dose of 7 mGy by IAEA.

  16. Reference levels for assays in opened installations of industrial radiography

    International Nuclear Information System (INIS)

    Leocadio, Joao C.; Tauhata, Luiz; Crispim, Verginia R.

    2001-01-01

    This work had as objectives to analyze the facilities open of industrial x-ray to obtain the distribution of doses in the operators and present proposed for the reference levels. The results of the monitoring revealed an improvement of the radiation protection conditions in the facilities and that the risk of potential exposure was reduced. The advantage of the proposed reference levels is that the supervisors would enlarge the frequency of audits in the facilities opened to accomplish the investigations and interventions.The facilities open with 'bunkers' presented distributions with 95% of the doses below 0,2 mSv and the distributions of the facilities with cordoned area they had 75% of the doses below 0,4 mSv. (author)

  17. Method of evaluation of diagnostics reference levels in computerized tomography

    International Nuclear Information System (INIS)

    Vega, Walter Flores

    1999-04-01

    Computerized tomography is a complex technique with several selectable exposition parameters delivering high doses to the patient. In this work it was developed a simple methodology to evaluate diagnostic reference levels in computerized tomography, using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Health Ministry. For evaluation of the MSAD, a dose distribution was obtained through a measured dose profile on the axial axis of a water phantom with thermoluminescence dosemeters, TLD-100, for different exam technique. The MSAD was evaluated hrough two distinct methods. First, it was evaluated by the integration of the dose profile of a single slice and, second, obtained by the integration on central slice of the profile of several slices. The latter is in of accordance with the ionization chamber method, suggesting to be the most practical method of dose evaluation to be applied in the diagnostic reference level assessment routine for CT, using TLDs. (author)

  18. The reference frame for encoding and retention of motion depends on stimulus set size.

    Science.gov (United States)

    Huynh, Duong; Tripathy, Srimant P; Bedell, Harold E; Öğmen, Haluk

    2017-04-01

    The goal of this study was to investigate the reference frames used in perceptual encoding and storage of visual motion information. In our experiments, observers viewed multiple moving objects and reported the direction of motion of a randomly selected item. Using a vector-decomposition technique, we computed performance during smooth pursuit with respect to a spatiotopic (nonretinotopic) and to a retinotopic component and compared them with performance during fixation, which served as the baseline. For the stimulus encoding stage, which precedes memory, we found that the reference frame depends on the stimulus set size. For a single moving target, the spatiotopic reference frame had the most significant contribution with some additional contribution from the retinotopic reference frame. When the number of items increased (Set Sizes 3 to 7), the spatiotopic reference frame was able to account for the performance. Finally, when the number of items became larger than 7, the distinction between reference frames vanished. We interpret this finding as a switch to a more abstract nonmetric encoding of motion direction. We found that the retinotopic reference frame was not used in memory. Taken together with other studies, our results suggest that, whereas a retinotopic reference frame may be employed for controlling eye movements, perception and memory use primarily nonretinotopic reference frames. Furthermore, the use of nonretinotopic reference frames appears to be capacity limited. In the case of complex stimuli, the visual system may use perceptual grouping in order to simplify the complexity of stimuli or resort to a nonmetric abstract coding of motion information.

  19. Hearing Tests on Mobile Devices: Evaluation of the Reference Sound Level by Means of Biological Calibration.

    Science.gov (United States)

    Masalski, Marcin; Kipiński, Lech; Grysiński, Tomasz; Kręcicki, Tomasz

    2016-05-30

    Hearing tests carried out in home setting by means of mobile devices require previous calibration of the reference sound level. Mobile devices with bundled headphones create a possibility of applying the predefined level for a particular model as an alternative to calibrating each device separately. The objective of this study was to determine the reference sound level for sets composed of a mobile device and bundled headphones. Reference sound levels for Android-based mobile devices were determined using an open access mobile phone app by means of biological calibration, that is, in relation to the normal-hearing threshold. The examinations were conducted in 2 groups: an uncontrolled and a controlled one. In the uncontrolled group, the fully automated self-measurements were carried out in home conditions by 18- to 35-year-old subjects, without prior hearing problems, recruited online. Calibration was conducted as a preliminary step in preparation for further examination. In the controlled group, audiologist-assisted examinations were performed in a sound booth, on normal-hearing subjects verified through pure-tone audiometry, recruited offline from among the workers and patients of the clinic. In both the groups, the reference sound levels were determined on a subject's mobile device using the Bekesy audiometry. The reference sound levels were compared between the groups. Intramodel and intermodel analyses were carried out as well. In the uncontrolled group, 8988 calibrations were conducted on 8620 different devices representing 2040 models. In the controlled group, 158 calibrations (test and retest) were conducted on 79 devices representing 50 models. Result analysis was performed for 10 most frequently used models in both the groups. The difference in reference sound levels between uncontrolled and controlled groups was 1.50 dB (SD 4.42). The mean SD of the reference sound level determined for devices within the same model was 4.03 dB (95% CI 3

  20. Estimating clinical chemistry reference values based on an existing data set of unselected animals.

    Science.gov (United States)

    Dimauro, Corrado; Bonelli, Piero; Nicolussi, Paola; Rassu, Salvatore P G; Cappio-Borlino, Aldo; Pulina, Giuseppe

    2008-11-01

    In an attempt to standardise the determination of biological reference values, the International Federation of Clinical Chemistry (IFCC) has published a series of recommendations on developing reference intervals. The IFCC recommends the use of an a priori sampling of at least 120 healthy individuals. However, such a high number of samples and laboratory analysis is expensive, time-consuming and not always feasible, especially in veterinary medicine. In this paper, an alternative (a posteriori) method is described and is used to determine reference intervals for biochemical parameters of farm animals using an existing laboratory data set. The method used was based on the detection and removal of outliers to obtain a large sample of animals likely to be healthy from the existing data set. This allowed the estimation of reliable reference intervals for biochemical parameters in Sarda dairy sheep. This method may also be useful for the determination of reference intervals for different species, ages and gender.

  1. Reference levels in PTCA as a function of procedure complexity

    International Nuclear Information System (INIS)

    Peterzol, A.; Quai, E.; Padovani, R.; Bernardi, G.; Kotre, C. J.; Dowling, A.

    2005-01-01

    The multicentre assessment of a procedure complexity index (CI) for the introduction of reference levels (RLs) in percutaneous transluminal coronary angio-plasties (PTCA) is presented here. PTCAs were investigated based on methodology proposed by Bernardi et al. Multiple linear stepwise regression analysis, including clinical, anatomical and technical factors, was performed to obtain fluoroscopy time predictors. Based on these regression coefficients, a scoring system was defined and CI obtained. CI was used to classify dose values into three groups: low, medium and high complexity procedures, since there was good correlation (r = 0.41; P 2 , and 12, 20 and 27 min for fluoroscopy time, for the three CI groups. (authors)

  2. Patient radiation doses and reference levels in pediatric interventional radiology

    Energy Technology Data Exchange (ETDEWEB)

    Habib Geryes, Bouchra; Lachaux, Julie; Boddaert, Nathalie; Brunelle, Francis [Hopital Universitaire Necker Enfants Malades, Department of Paediatric Radiology, Paris (France); Bak, Adeline; Ozanne, Augustin; Saliou, Guillaume [Hopital Bicetre, Hopitaux Universitaires Paris-Sud, Department of Neuroradiology, Le Kremlin Bicetre (France); Naggara, Olivier [Hopital Universitaire Necker Enfants Malades, Department of Paediatric Radiology, Paris (France); Centre Hospitalier Sainte-Anne, Universite Paris Descartes Sorbonne Paris Cite, Centre de Psychiatrie et Neurosciences, INSERM S894, DHU Neurovasculaire, Paris (France); Centre Hospitalier Sainte-Anne, Department of Neuroradiology, Universite Paris Descartes, Sorbonne Paris Cite, INSERM UMR894, Paris (France)

    2017-09-15

    To describe, in a multicentric paediatric population, reference levels (RLs) for three interventional radiological procedures. From January 2012 to March 2015, children scheduled for an interventional radiological procedure in two French tertiary centres were retrospectively included and divided into four groups according to age: children younger than 2 years (A1), aged 2-7 years (A5), 8-12 years (A10) and 13-18 years (A15). Three procedures were identified: cerebral digital subtraction angiography (DSA), brain arteriovenous malformation (bAVM) embolization, and head and neck superficial vascular malformation (SVM) percutaneous sclerotherapy. Demographic and dosimetric data, including dose area product (DAP), were collected. 550 procedures were included. For DSA (162 procedures), the proposed RL values in DAP were 4, 18, 12 and 32 Gy.cm{sup 2} in groups A1, A5, A10 and A15, respectively. For bAVM embolization (258 procedures), values were 33, 70, 105 and 88 Gy.cm{sup 2} in groups A1, A5, A10 and A15, respectively. For SVM sclerotherapy (130 procedures), values were 350, 790, 490 and 248 mGy.cm{sup 2} in groups A1, A5, A10 and A15, respectively. Consecutive data were available to permit a proposal of reference levels for three major paediatric interventional radiology procedures. (orig.)

  3. Automatic Enhancement of the Reference Set for Multi-Criteria Sorting in The Frame of Theseus Method

    Directory of Open Access Journals (Sweden)

    Fernandez Eduardo

    2014-05-01

    Full Text Available Some recent works have established the importance of handling abundant reference information in multi-criteria sorting problems. More valid information allows a better characterization of the agent’s assignment policy, which can lead to an improved decision support. However, sometimes information for enhancing the reference set may be not available, or may be too expensive. This paper explores an automatic mode of enhancing the reference set in the framework of the THESEUS multi-criteria sorting method. Some performance measures are defined in order to test results of the enhancement. Several theoretical arguments and practical experiments are provided here, supporting a basic advantage of the automatic enhancement: a reduction of the vagueness measure that improves the THESEUS accuracy, without additional efforts from the decision agent. The experiments suggest that the errors coming from inadequate automatic assignments can be kept at a manageable level.

  4. A parametric level-set method for partially discrete tomography

    NARCIS (Netherlands)

    A. Kadu (Ajinkya); T. van Leeuwen (Tristan); K.J. Batenburg (Joost)

    2017-01-01

    textabstractThis paper introduces a parametric level-set method for tomographic reconstruction of partially discrete images. Such images consist of a continuously varying background and an anomaly with a constant (known) grey-value. We express the geometry of the anomaly using a level-set function,

  5. Identifying Heterogeneities in Subsurface Environment using the Level Set Method

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Hongzhuan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lu, Zhiming [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vesselinov, Velimir Valentinov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-25

    These are slides from a presentation on identifying heterogeneities in subsurface environment using the level set method. The slides start with the motivation, then explain Level Set Method (LSM), the algorithms, some examples are given, and finally future work is explained.

  6. Application of diagnostic reference levels in medical practice

    Energy Technology Data Exchange (ETDEWEB)

    Bourguignon, Michel [Faculty of Medicine of Paris, Deputy Director General, Nuclear Safety Authority (ASN), Paris (France)

    2006-07-01

    Diagnosis reference levels (D.R.L.) are defined in the Council Directive 97/43 EURATOM as 'Dose levels in medical radio diagnosis practices or in the case of radiopharmaceuticals, levels of activity, for typical examinations for groups of standards-sized patients or standards phantoms for broadly defined types of equipment. These levels are expected not to be exceeded for standard procedures when good and normal practice regarding diagnostic and technical performance is applied'. Thus D.R.L. apply only to diagnostic procedures and does not apply to radiotherapy. Radiation protection of patients is based on the application of 2 major radiation protection principles, justification and optimization. The justification principle must be respected first because the best way to protect the patient is not to carry a useless test. Radiation protection of the patient is a continuous process and local dose indicator values in the good range should not prevent the radiologist or nuclear medicine physician to continue to optimize their practice. (N.C.)

  7. Application of diagnostic reference levels in medical practice

    International Nuclear Information System (INIS)

    Bourguignon, Michel

    2006-01-01

    Diagnosis reference levels (D.R.L.) are defined in the Council Directive 97/43 EURATOM as 'Dose levels in medical radio diagnosis practices or in the case of radiopharmaceuticals, levels of activity, for typical examinations for groups of standards-sized patients or standards phantoms for broadly defined types of equipment. These levels are expected not to be exceeded for standard procedures when good and normal practice regarding diagnostic and technical performance is applied'. Thus D.R.L. apply only to diagnostic procedures and does not apply to radiotherapy. Radiation protection of patients is based on the application of 2 major radiation protection principles, justification and optimization. The justification principle must be respected first because the best way to protect the patient is not to carry a useless test. Radiation protection of the patient is a continuous process and local dose indicator values in the good range should not prevent the radiologist or nuclear medicine physician to continue to optimize their practice. (N.C.)

  8. A new level set model for multimaterial flows

    Energy Technology Data Exchange (ETDEWEB)

    Starinshak, David P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Karni, Smadar [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Mathematics; Roe, Philip L. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of AerospaceEngineering

    2014-01-08

    We present a new level set model for representing multimaterial flows in multiple space dimensions. Instead of associating a level set function with a specific fluid material, the function is associated with a pair of materials and the interface that separates them. A voting algorithm collects sign information from all level sets and determines material designations. M(M ₋1)/2 level set functions might be needed to represent a general M-material configuration; problems of practical interest use far fewer functions, since not all pairs of materials share an interface. The new model is less prone to producing indeterminate material states, i.e. regions claimed by more than one material (overlaps) or no material at all (vacuums). It outperforms existing material-based level set models without the need for reinitialization schemes, thereby avoiding additional computational costs and preventing excessive numerical diffusion.

  9. On detecting reference level of acrolein content in children's blood

    Directory of Open Access Journals (Sweden)

    T.S. Ulanova

    2017-03-01

    Full Text Available The article gives the results of complex chemical-analytical and clinical-laboratory research in course of which biological media of children living in Perm region were examined. To study impacts exerted by exogenous acrolein we examined 156 children in 2014–2016, aged 5–10, attending pre-school facilities and schools, and living in Perm region. As we conducted this research we detected average annual acrolein concentration in atmosphere on the examined territory; this concentration was equal to 0.000024 mg/m3, and it was 1.2 times higher than reference acrolein concentration in the air for chronic inhalation exposure. Average group acrolein concentration in children's blood was 1.2 times authentically higher (р3.96, p≤0.05. We used increased content of delta-aminolevulinic acid in urine as a limiting marker for effects occurring at chronic inhalation exposure to acrolein. Basing on the results of the performed examination we recommend concentration equal to 0.10 mgr/dm 3 as a reference level of acrolein content in blood at chronic inhalation exposure.

  10. Alluvial architecture of fluvio-deltaic successions: a review with special reference to Holocene settings

    NARCIS (Netherlands)

    Gouw, M.J.P.

    2007-01-01

    Alluvial architecture has been subject of many studies because of the occurrence of natural resources in ancient fluvial successions. This paperprovides an overview of the current state of research on alluvial architecture with special reference to Holocene fluvio-deltaic settings. Severalexamples

  11. Evaluating Question, Persuade, Refer (QPR) Suicide Prevention Training in a College Setting

    Science.gov (United States)

    Mitchell, Sharon L.; Kader, Mahrin; Darrow, Sherri A.; Haggerty, Melinda Z.; Keating, Niki L.

    2013-01-01

    This study assesses short-term and long-term learning outcomes of Question, Persuade, Refer (QPR) suicide prevention training in a college setting. Two hundred seventy-three participants completed pretest, posttest, and follow-up surveys regarding suicide prevention knowledge, attitudes, and skills. Results indicated: (a) increases in suicide…

  12. The processing cost of reference-set computation: guess patterns in acquisition

    NARCIS (Netherlands)

    Reinhart, T.

    1999-01-01

    An idea which got much attention in linguistic theory in the nineties is that the well-formedness of sentences is not always determined by absolute conditions, but it may be determined by a selection of the optimal competitor out of a relevant reference-set. A restricted version of this was assumed

  13. Diagnostic reference levels in digital mammography: a systematic review

    International Nuclear Information System (INIS)

    Suleiman, Moayyad E.; Brennan, Patrick C.; McEntee, Mark F.

    2015-01-01

    This study aims to review the literature on existing diagnostic reference levels (DRLs) in digital mammography and methodologies for establishing them. To this end, a systematic search through Medline, Cinahl, Web of Science, Scopus and Google scholar was conducted using search terms extracted from three terms: DRLs, digital mammography and breast screen. The search resulted in 1539 articles of which 22 were included after a screening process. Relevant data from the included studies were summarised and analysed. Differences were found in the methods utilised to establish DRLs including test subjects types, protocols followed, conversion factors employed, breast compressed thicknesses and percentile values adopted. These differences complicate comparison of DRLs among countries; hence, an internationally accepted protocol would be valuable so that international comparisons can be made. (authors)

  14. Novel gene sets improve set-level classification of prokaryotic gene expression data.

    Science.gov (United States)

    Holec, Matěj; Kuželka, Ondřej; Železný, Filip

    2015-10-28

    Set-level classification of gene expression data has received significant attention recently. In this setting, high-dimensional vectors of features corresponding to genes are converted into lower-dimensional vectors of features corresponding to biologically interpretable gene sets. The dimensionality reduction brings the promise of a decreased risk of overfitting, potentially resulting in improved accuracy of the learned classifiers. However, recent empirical research has not confirmed this expectation. Here we hypothesize that the reported unfavorable classification results in the set-level framework were due to the adoption of unsuitable gene sets defined typically on the basis of the Gene ontology and the KEGG database of metabolic networks. We explore an alternative approach to defining gene sets, based on regulatory interactions, which we expect to collect genes with more correlated expression. We hypothesize that such more correlated gene sets will enable to learn more accurate classifiers. We define two families of gene sets using information on regulatory interactions, and evaluate them on phenotype-classification tasks using public prokaryotic gene expression data sets. From each of the two gene-set families, we first select the best-performing subtype. The two selected subtypes are then evaluated on independent (testing) data sets against state-of-the-art gene sets and against the conventional gene-level approach. The novel gene sets are indeed more correlated than the conventional ones, and lead to significantly more accurate classifiers. The novel gene sets are indeed more correlated than the conventional ones, and lead to significantly more accurate classifiers. Novel gene sets defined on the basis of regulatory interactions improve set-level classification of gene expression data. The experimental scripts and other material needed to reproduce the experiments are available at http://ida.felk.cvut.cz/novelgenesets.tar.gz.

  15. Development of a low-level radon reference chamber; Entwicklung einer Low-Level-Radon-Referenzkammer

    Energy Technology Data Exchange (ETDEWEB)

    Linzmaier, Diana

    2013-01-04

    The naturally occurring, radioactive noble gas radon-222 exists worldwide in different activity concentrations in the air. During the decay of radon-222, decay products are generated which are electrically charged and attach to aerosols in the air. Together with the aerosols, the radon is inhaled and exhaled by humans. While the radon is nearly completely exhaled, ca. 20 % of the inhaled aerosols remain in the lungs in one breath cycle. Due to ionizing radiation, in a chain of events, lung cancer might occur. Consequently, radon and its decay products are according to the current findings the second leading cause of lung cancer. At the workplace and in the home measurements of radon activity concentration are performed to determine the radiation exposition of humans. All measurement devices for the determination of radon activity concentration are calibrated above 1000 Bq/m{sup 3}, even though the mean value of the present investigation in Germany shows only 50 Bq/m{sup 3}. For the calibration of measurement devices in the range below 1000 Bq/m{sup 3} over a long time period, the generation of a stable reference atmosphere is presented in this work. Due to a long term calibration (t>5 days) of the measurement devices, smaller uncertainties result for the calibration factor. For the calibration procedure, a so-called low-level radon reference chamber was set up and started operation. The generation of a stable reference atmosphere is effected by means of emanation sources which consist of a radium-226 activity standard. On the basis of {gamma}-spectrometry, the effective emanation coefficient ofthe emanation sources is determined. The traceability of the activity concentration in the reference volume is realized via the activity ofthe radium-226, the emanation coefficient and the volume. With the emanation sources produced, stable reference atmospheres within the range of 150 Bq/m{sup 3} to 1900 Bq/m{sup 3} are achieved. For the realization, maintenance and

  16. Volume Sculpting Using the Level-Set Method

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Christensen, Niels Jørgen

    2002-01-01

    In this paper, we propose the use of the Level--Set Method as the underlying technology of a volume sculpting system. The main motivation is that this leads to a very generic technique for deformation of volumetric solids. In addition, our method preserves a distance field volume representation....... A scaling window is used to adapt the Level--Set Method to local deformations and to allow the user to control the intensity of the tool. Level--Set based tools have been implemented in an interactive sculpting system, and we show sculptures created using the system....

  17. Establishment of dose reference levels for mammography in Greece

    International Nuclear Information System (INIS)

    Kalathaki, M.; Hourdakis, C.J.; Economides, S.; Tritakis, P.; Manousaridis, G.; Kalyvas, N.; Simantirakis, G.; Kipouros, P.; Kamenopoulou, V.

    2006-01-01

    Full text of publication follows: Diagnostic Reference Levels (D.R.L.) are dose levels established in medical practices for typical x-ray examinations concerning groups of standard size patients or standard phantoms and broadly defined types of equipment. When good and normal practice is performed, these levels are not expected to be exceeded. This work is an attempt to establish for the first time the D.R.L. for mammography in Greece. At present, there are 402 mammographic systems in clinical use all over the country. This study that lasted 3 years (2000-2003), includes 117 of these systems, 85% of which are installed in private and 15% in public sector countrywide. Measurements of entrance surface dose (E.S.D.) were performed as a part of the regular inspections performed by the Licensing and Inspections Department of Greek Atomic Energy Commission on the basis of the laboratories licensing procedure. Moreover, the entire performance of the mammographic units was assessed by quantitative and qualitative measurements of specific parameters. In order to establish the national D.R.L., a standard phantom was used during the quality control of the mammographic units and E.S.D. measurements were performed based on the clinical practice of each laboratory. The D.R.L. for this type of examination was established according to the 75. percentile of the E.S.D. curve and found equal to 7 mGy per single view. The comparison of this value with the one reported by the European Commission (10 mGy per view), indicates that the D.R.L. for mammography is lower in Greece. However, the primary concern of a mammographic examination is to keep breast dose as low as reasonably achievable while providing images with the maximum amount of diagnostic information. The quality of the produced images was therefore assessed for all systems examined, regardless of meeting or exceeding the quality criteria reference surface entrance dose. The results showed that the average total score of the

  18. Provincial practice: adopting the new reference levels for Radon

    International Nuclear Information System (INIS)

    Kennedy, Christine; Johnson, Darryl

    2008-01-01

    Full text: In June 2007 new reference levels for radon gas were announced from Health Canada. These new levels brought new attention to the issue of radon gas exposure in the Province of Newfoundland and Labrador. Research in radon gas exposure has a long history in the fluorspar mines of the Burin Peninsula, indeed, occupational data from the 1950 's and 60 's had been included in Darby et al. large scale occupational meta analyses. Radon was also implicated in a royal commission of occupational mining hazards in Newfoundland in 1968. Although, the occupational exposures of miners have been well documented, very little is known about population exposures in indoor spaces. Geological maps are currently being composed for national areas, but data for this province is not yet published. Information about mining tailings used in construction materials or as fill is very poor (unlike the data known for uranium mining tailings in Ontario and Manitoba). The challenges of estimating radon exposures for the province are myriad and these are explored here in this narrative study of how new information has to be generated, and then incorporated into new environmental public health policies for a population. The process by which new scientific information informs public health policy is described in this study of radon in Newfoundland and Labrador. Anticipated regulations for new buildings are discussed. (author)

  19. Reference dose levels for dental panoramic radiography in Gwangju (South Korea)

    International Nuclear Information System (INIS)

    Lee, J. S.; Kim, Y. H.; Yoon, S. J.; Kang, B. C.

    2010-01-01

    This study assessed the reference dose levels for dental panoramic radiography in Gwangju city (South Korea) based on the dose width product (DWP) and compared them with those already established elsewhere. A total of 44 panoramic dental radiographic sets (36 digital and 8 analogue panoramic sets) in 41 dental clinics in Gwangju city were chosen. The third quartile DWP was determined from 429 surface dose measurements of the adult surface dose in panoramic dental radiography. The third quartile DWP for panoramic radiography was 60.1 mGy mm. The proposed DWP reference levels of 60.1 mGy mm were less than or equal to those previously reported in other countries, such as Italy and UK, and acceptable for panoramic radiography in Gwangju (KR). (authors)

  20. The need for national diagnostic reference levels: entrance surface dose measurement in intraoral radiography

    International Nuclear Information System (INIS)

    Mortazavi, S. M. J.; Shareghi, A.; Kavousi, A.; Ghiassi-Nejad, M.; Jafari-Zadeh, M.; Nazeri, F.; Mozdarani, H.

    2004-01-01

    Background: Intraoral radiographies are the most frequent X-ray examinations in humans. According to International Commission on Radiation Protection recommendations, the selection of a diagnostic reference level should be specific to a country or region. Critical organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral radiography, a National Radiation Protection Department-sponsored pilot study was carried out. Materials and methods: thermoluminescent dosimetry is widely acknowledged to be the recommended method for measuring entrance surface doses. In this study, entrance surface doses was measured using LiF thermoluminescent dosimeters on the skin (either mandibular or maxillary arcs) of 40 patients. Three thermoluminescent dosimetry chips were placed on the skin of each patient. The doses were averaged for each radiography and mean entrance surface doses of all patients calculated. Results: the mean ±SD entrance surface dose at the center of the beam on the patient's skin in intraoral radiography was 1.173 ±0.606 mGy (ranged from 0.01 o 0.40 m Gy). The mean entrance surface doses for male and female patients were 1.380± 0.823, and 1.004± 0.258 respectively. No statistically significant difference was found between these means. Despite its necessity , in national level , there is no published data on the diagnostic reference levels for intraoral radiography. However, the results obtained in this study are lower than those reported by investigators in other countries. Conclusion: in IR Iran , due to lack of large scale studies, no diagnostic reference levels have been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it is not possible to clarify whether in intraoral radiographies any dose reduction techniques are needed. We intend to perform similar nationwide studies to set the

  1. A level set method for multiple sclerosis lesion segmentation.

    Science.gov (United States)

    Zhao, Yue; Guo, Shuxu; Luo, Min; Shi, Xue; Bilello, Michel; Zhang, Shaoxiang; Li, Chunming

    2018-06-01

    In this paper, we present a level set method for multiple sclerosis (MS) lesion segmentation from FLAIR images in the presence of intensity inhomogeneities. We use a three-phase level set formulation of segmentation and bias field estimation to segment MS lesions and normal tissue region (including GM and WM) and CSF and the background from FLAIR images. To save computational load, we derive a two-phase formulation from the original multi-phase level set formulation to segment the MS lesions and normal tissue regions. The derived method inherits the desirable ability to precisely locate object boundaries of the original level set method, which simultaneously performs segmentation and estimation of the bias field to deal with intensity inhomogeneity. Experimental results demonstrate the advantages of our method over other state-of-the-art methods in terms of segmentation accuracy. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Some numerical studies of interface advection properties of level set ...

    Indian Academy of Sciences (India)

    explicit computational elements moving through an Eulerian grid. ... location. The interface is implicitly defined (captured) as the location of the discontinuity in the ... This level set function is advected with the background flow field and thus ...

  3. Evaluating the construct of triage acuity against a set of reference vignettes developed via modified Delphi method.

    Science.gov (United States)

    Twomey, Michèle; Wallis, Lee A; Myers, Jonathan E

    2014-07-01

    To evaluate the construct of triage acuity as measured by the South African Triage Scale (SATS) against a set of reference vignettes. A modified Delphi method was used to develop a set of reference vignettes. Delphi participants completed a 2-round consensus-building process, and independently assigned triage acuity ratings to 100 written vignettes unaware of the ratings given by others. Triage acuity ratings were summarised for all vignettes, and only those that reached 80% consensus during round 2 were included in the reference set. Triage ratings for the reference vignettes given by two independent experts using the SATS were compared with the ratings given by the international Delphi panel. Measures of sensitivity, specificity, associated percentages for over-triage/under-triage were used to evaluate the construct of triage acuity (as measured by the SATS) by examining the association between the ratings by the two experts and the international panel. On completion of the Delphi process, 42 of the 100 vignettes reached 80% consensus on their acuity rating and made up the reference set. On average, over all acuity levels, sensitivity was 74% (CI 64% to 82%), specificity 92% (CI 87% to 94%), under-triage occurred 14% (CI 8% to 23%) and over-triage 12% (CI 8% to 23%) of the time. The results of this study provide an alternative to evaluating triage scales against the construct of acuity as measured with the SATS. This method of using 80% consensus vignettes may, however, systematically bias the validity estimate towards better performance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Discussion on Implementation of ICRP Recommendations Concerning Reference Levels and Optimisation

    International Nuclear Information System (INIS)

    2013-02-01

    International Commission on Radiological Protection (ICRP) Publication 103, 'The 2007 Recommendations of the International Commission on Radiological Protection', issued in 2007, defines emergency exposure situations as unexpected situations that may require the implementation of urgent protective actions and perhaps longer term protective actions. The ICRP continues to recommend optimisation and the use of reference levels to ensure an adequate degree of protection in regard to exposure to ionising radiation in emergency exposure situations. Reference levels represent the level of dose or risk above which it is judged to be inappropriate to plan to allow exposures to occur and for which protective actions should therefore be planned and optimised. National authorities are responsible for establishing reference levels. The Expert Group on the Implementation of New International Recommendations for Emergency Exposure Situations (EGIRES) performed a survey to analyse the established processes for optimisation of the protection strategy for emergency exposure situations and for practical implementation of the reference level concept in several member states of the Nuclear Energy Agency (NEA). The EGIRES collected information on several national optimisation strategy definitions, on optimisation of protection for different protective actions, and also on optimisation of urgent protective actions. In addition, national criteria for setting reference levels, their use, and relevant processes, including specific triggers and dosimetric quantifies in setting reference levels, are focus points that the EGIRES also evaluated. The analysis of national responses to this 2011 survey shows many differences in the interpretation and application of the established processes and suggests that most countries are still in the early stages of implementing these processes. Since 2011, national authorities have continued their study of the ICRP recommendations to incorporate them into

  5. Adaptive Reference Levels in a Level-Crossing Analog-to-Digital Converter

    Directory of Open Access Journals (Sweden)

    Andrew C. Singer

    2008-11-01

    Full Text Available Level-crossing analog-to-digital converters (LC ADCs have been considered in the literature and have been shown to efficiently sample certain classes of signals. One important aspect of their implementation is the placement of reference levels in the converter. The levels need to be appropriately located within the input dynamic range, in order to obtain samples efficiently. In this paper, we study optimization of the performance of such an LC ADC by providing several sequential algorithms that adaptively update the ADC reference levels. The accompanying performance analysis and simulation results show that as the signal length grows, the performance of the sequential algorithms asymptotically approaches that of the best choice that could only have been chosen in hindsight within a family of possible schemes.

  6. Identification of a set of endogenous reference genes for miRNA expression studies in Parkinson's disease blood samples.

    Science.gov (United States)

    Serafin, Alice; Foco, Luisa; Blankenburg, Hagen; Picard, Anne; Zanigni, Stefano; Zanon, Alessandra; Pramstaller, Peter P; Hicks, Andrew A; Schwienbacher, Christine

    2014-10-10

    Research on microRNAs (miRNAs) is becoming an increasingly attractive field, as these small RNA molecules are involved in several physiological functions and diseases. To date, only few studies have assessed the expression of blood miRNAs related to Parkinson's disease (PD) using microarray and quantitative real-time PCR (qRT-PCR). Measuring miRNA expression involves normalization of qRT-PCR data using endogenous reference genes for calibration, but their choice remains a delicate problem with serious impact on the resulting expression levels. The aim of the present study was to evaluate the suitability of a set of commonly used small RNAs as normalizers and to identify which of these miRNAs might be considered reliable reference genes in qRT-PCR expression analyses on PD blood samples. Commonly used reference genes snoRNA RNU24, snRNA RNU6B, snoRNA Z30 and miR-103a-3p were selected from the literature. We then analyzed the effect of using these genes as reference, alone or in any possible combination, on the measured expression levels of the target genes miR-30b-5p and miR-29a-3p, which have been previously reported to be deregulated in PD blood samples. We identified RNU24 and Z30 as a reliable and stable pair of reference genes in PD blood samples.

  7. Determination and compensation of the “reference surface” from redundant sets of surface measurements

    Energy Technology Data Exchange (ETDEWEB)

    Polack, François, E-mail: francois.polack@synchrotron-soleil.fr [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette Cedex (France); Thomasset, Muriel, E-mail: muriel.thomasset@synchrotron-soleil.fr [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette Cedex (France)

    2013-05-11

    When trying to measure an optical surface at utmost absolute precision, the problem of the missing or unknown “reference surface” is often encountered. It is obvious with Fizeau and Michelson's interferometry, where the height difference between the surface under test (SUT) and a reference surface is measured. It is also true from slope measurements in long trace profilers (LTP), where due to small construction errors, the response to a perfectly flat ideal surface can be considered as an unknown reference to be subtracted from the measurement data. As no “perfect artifact” can exist, these references cannot be directly determined. The addition of the unknown reference can severely bias the reconstructed surface when field stitching is applied. The results of ptychography have proved that when a measurement is a function of a unique object function with a translated but unique response function, the redundancy of a large set of data allows accurate reconstructions of the object and response function despite the presence of measurement noise. In the case of LTP and interferometry, the basic problem is linear and can be solved by linear algebra rather than iteratively. The method has been already applied to SOLEIL and ESRF LTPs and is succesfully used on a regular base. We show here that the method can be also applied to interferometry and improve stitching results.

  8. Exploring the level sets of quantum control landscapes

    International Nuclear Information System (INIS)

    Rothman, Adam; Ho, Tak-San; Rabitz, Herschel

    2006-01-01

    A quantum control landscape is defined by the value of a physical observable as a functional of the time-dependent control field E(t) for a given quantum-mechanical system. Level sets through this landscape are prescribed by a particular value of the target observable at the final dynamical time T, regardless of the intervening dynamics. We present a technique for exploring a landscape level set, where a scalar variable s is introduced to characterize trajectories along these level sets. The control fields E(s,t) accomplishing this exploration (i.e., that produce the same value of the target observable for a given system) are determined by solving a differential equation over s in conjunction with the time-dependent Schroedinger equation. There is full freedom to traverse a level set, and a particular trajectory is realized by making an a priori choice for a continuous function f(s,t) that appears in the differential equation for the control field. The continuous function f(s,t) can assume an arbitrary form, and thus a level set generally contains a family of controls, where each control takes the quantum system to the same final target value, but produces a distinct control mechanism. In addition, although the observable value remains invariant over the level set, other dynamical properties (e.g., the degree of robustness to control noise) are not specifically preserved and can vary greatly. Examples are presented to illustrate the continuous nature of level-set controls and their associated induced dynamical features, including continuously morphing mechanisms for population control in model quantum systems

  9. On multiple level-set regularization methods for inverse problems

    International Nuclear Information System (INIS)

    DeCezaro, A; Leitão, A; Tai, X-C

    2009-01-01

    We analyze a multiple level-set method for solving inverse problems with piecewise constant solutions. This method corresponds to an iterated Tikhonov method for a particular Tikhonov functional G α based on TV–H 1 penalization. We define generalized minimizers for our Tikhonov functional and establish an existence result. Moreover, we prove convergence and stability results of the proposed Tikhonov method. A multiple level-set algorithm is derived from the first-order optimality conditions for the Tikhonov functional G α , similarly as the iterated Tikhonov method. The proposed multiple level-set method is tested on an inverse potential problem. Numerical experiments show that the method is able to recover multiple objects as well as multiple contrast levels

  10. Patient dose measurements in fluoroscopic examinations, aiming to the establishment of reference levels in Brazil

    International Nuclear Information System (INIS)

    Canevaro, L.; Drexler, G.

    2001-01-01

    This work was performed to investigate the actual exposure levels of the patients submitted to fluoroscopic procedures in diagnostic radiology. The data will be useful for a baseline in the establishment of local reference levels for fluoroscopic procedures, as recommended by the European Commission and IAEA. At present time there are no internationally accepted definitions for references levels for fluoroscopic complex procedures. Dose-area product (DAP) meters were employed in a pilot survey expressing the radiation exposures in terms of this quantity. This class of instrumentation has not yet been employed in Brazil. Parameters recorded were radiographic technique, fluoroscopy time, number of images, fluoroscopic and radiographic field sizes and DAPs. For fluoroscopy practice, a reference parameters set is recommended, instead of one diagnostic reference level. High patient exposures were found, calling for joined actions of health authorities, physicians, medical physicists, technicians and manufacturers. Monitoring of patient exposure, optimizing the radiation protection and establishing quantitative assessments of the exposition to the population in Brazil in this kind of procedure is important. (author)

  11. Diagnostic reference levels in intraoral dental radiography in Korea

    International Nuclear Information System (INIS)

    Kim, Eun Kyung; Han, Won Jeong; Choi, Jin Woo; Jung, Yun Hoa; Yoon, Suk Ja; Lee, Jae Seo

    2012-01-01

    The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 mGycm2 (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 mGycm 2 (DAP). Doses at university dental hospitals were lower than those at dental clinics (p 2 (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

  12. A protein-based set of reference markers for liver tissues and hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Sun, Stella; Yi, Xin; Poon, Ronnie TP; Yeung, Chun; Day, Philip JR; Luk, John M

    2009-01-01

    During the last decade, investigations have focused on revealing genes or proteins that are involved in HCC carcinogenesis using either genetic or proteomic techniques. However, these studies are overshadowed by a lack of good internal reference standards. The need to identify 'housekeeping' markers, whose expression is stable in various experimental and clinical conditions, is therefore of the utmost clinical relevance in quantitative studies. This is the first study employed 2-DE analysis to screen for potential reference markers and aims to correlate the abundance of these proteins with their level of transcript expression. A Chinese cohort of 224 liver tissues samples (105 cancerous, 103 non-tumourous cirrhotic, and 16 normal) was profiled using 2-DE analysis. Expression of the potential reference markers was confirmed by western blot, immunohistochemistry and real-time quantitative PCR. geNorm algorithm was employed for gene stability measure of the identified reference markers. The expression levels of three protein markers beta-actin (ACTB), heat shock protein 60 (HSP60), and protein disulphide isomerase (PDI) were found to be stable using p-values (p > 0.99) as a ranking tool in all 224 human liver tissues examined by 2-DE analysis. Of high importance, ACTB and HSP 60 were successfully validated at both protein and mRNA levels in human hepatic tissues by western blot, immunohistochemistry and real-time quantitative PCR. In addition, no significant correlation of these markers with any clinicopathological features of HCC and cirrhosis was found. Gene stability measure of these two markers with other conventionally applied housekeeping genes was assessed by the geNorm algorithm, which ranked ACTB and HSP60 as the most stable genes among this cohort of clinical samples. Our findings identified 2 reference markers that exhibited stable expression across human liver tissues with different conditions thus should be regarded as reliable reference

  13. Level-Set Topology Optimization with Aeroelastic Constraints

    Science.gov (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia

    2015-01-01

    Level-set topology optimization is used to design a wing considering skin buckling under static aeroelastic trim loading, as well as dynamic aeroelastic stability (flutter). The level-set function is defined over the entire 3D volume of a transport aircraft wing box. Therefore, the approach is not limited by any predefined structure and can explore novel configurations. The Sequential Linear Programming (SLP) level-set method is used to solve the constrained optimization problems. The proposed method is demonstrated using three problems with mass, linear buckling and flutter objective and/or constraints. A constraint aggregation method is used to handle multiple buckling constraints in the wing skins. A continuous flutter constraint formulation is used to handle difficulties arising from discontinuities in the design space caused by a switching of the critical flutter mode.

  14. Level Set Structure of an Integrable Cellular Automaton

    Directory of Open Access Journals (Sweden)

    Taichiro Takagi

    2010-03-01

    Full Text Available Based on a group theoretical setting a sort of discrete dynamical system is constructed and applied to a combinatorial dynamical system defined on the set of certain Bethe ansatz related objects known as the rigged configurations. This system is then used to study a one-dimensional periodic cellular automaton related to discrete Toda lattice. It is shown for the first time that the level set of this cellular automaton is decomposed into connected components and every such component is a torus.

  15. Arterial blood gas reference values for sea level and an altitude of 1,400 meters.

    Science.gov (United States)

    Crapo, R O; Jensen, R L; Hegewald, M; Tashkin, D P

    1999-11-01

    Blood gas measurements were collected on healthy lifetime nonsmokers at sea level (n = 96) and at an altitude of 1,400 meters (n = 243) to establish reference equations. At each study site, arterial blood samples were analyzed in duplicate on two separate blood gas analyzers and CO-oximeters. Arterial blood gas variables included Pa(O(2)), Pa(CO(2)), pH, and calculated alveolar-arterial PO(2) difference (AaPO(2)). CO-oximeter variables were Hb, COHb, MetHb, and Sa(O(2)). Subjects were 18 to 81 yr of age with 166 male and 173 female. Outlier data were excluded from multiple regression analysis, and reference equations were fitted to the data in two ways: (1) best fit using linear, squared, and cross-product terms; (2) simple equations, including only the variables that explained at least 3% of the variance. Two sets of equations were created: (1) using only the sea level data and (2) using the combined data with barometric pressure as an independent variable. Comparisons with earlier studies revealed small but significant differences; the decline in Pa(O(2)) with age at each altitude was consistent with most previous studies. At sea level, the equation that included barometric pressure predicted Pa(O(2)) slightly better than the sea level specific equation. The inclusion of barometric pressure in the equations allows better prediction of blood gas reference values at sea level and at altitudes as high as 1,400 meters.

  16. A summarization approach for Affymetrix GeneChip data using a reference training set from a large, biologically diverse database

    Directory of Open Access Journals (Sweden)

    Tripputi Mark

    2006-10-01

    Full Text Available Abstract Background Many of the most popular pre-processing methods for Affymetrix expression arrays, such as RMA, gcRMA, and PLIER, simultaneously analyze data across a set of predetermined arrays to improve precision of the final measures of expression. One problem associated with these algorithms is that expression measurements for a particular sample are highly dependent on the set of samples used for normalization and results obtained by normalization with a different set may not be comparable. A related problem is that an organization producing and/or storing large amounts of data in a sequential fashion will need to either re-run the pre-processing algorithm every time an array is added or store them in batches that are pre-processed together. Furthermore, pre-processing of large numbers of arrays requires loading all the feature-level data into memory which is a difficult task even with modern computers. We utilize a scheme that produces all the information necessary for pre-processing using a very large training set that can be used for summarization of samples outside of the training set. All subsequent pre-processing tasks can be done on an individual array basis. We demonstrate the utility of this approach by defining a new version of the Robust Multi-chip Averaging (RMA algorithm which we refer to as refRMA. Results We assess performance based on multiple sets of samples processed over HG U133A Affymetrix GeneChip® arrays. We show that the refRMA workflow, when used in conjunction with a large, biologically diverse training set, results in the same general characteristics as that of RMA in its classic form when comparing overall data structure, sample-to-sample correlation, and variation. Further, we demonstrate that the refRMA workflow and reference set can be robustly applied to naïve organ types and to benchmark data where its performance indicates respectable results. Conclusion Our results indicate that a biologically diverse

  17. Derived reference levels for prenatal exposure in a radiological emergency

    International Nuclear Information System (INIS)

    Nuccetelli, C.; Risica, S.; Rogani, A.

    2002-01-01

    After the Chernobyl accident many countries renewed their radiological emergency plans, also considering the possibility of over boundary accidents. This has been set out by the 96/29/Euratom Directive (Council Directive, 1996), which states that E ach Member State shall ensure that account is taken of the fact that radiological emergencies may occur in connection with practices on or outside its territory and affect it . Moreover, after September 11, 2001, the need to prepare emergency plans for possible terroristic attacks became evident and these plans are now being worked out in many countries for intervention in case of biological, chemical and/or radiological risk. In the event of radiological emergency, all decisions to be taken are based on possible doses to critical groups (European Commission, 1997), which are the population groups most at risk. These critical groups are, in most cases, infants or children, given that dose coefficients for these age groups are generally higher than for adults. However, a new ICRP Recommendation (ICRP, 2001) has recently been published that gives dose coefficients for embryo/foetus due to intake by the mother, by inhalation or ingestion, of 31 radionuclides. Also as a result of the revaluation in the last years of the possible health effects of prenatal exposure to ionising radiation (see e.g. the review in P. Fattibene et al., 1999), the consequences for the embryo/foetus of a possible radiological emergency connected to a nuclear plant and to possible dispersion of Depleted Uranium (DU) in the environment are analysed and discussed in this paper. For the former type of accident, Derived Intervention Levels (DILs) are calculated for prenatal exposure due to acute inhalation by the mother (female member of the public) and an assessment is performed of ingestion doses for the offspring resulting from consumption of foodstuffs by the mother of which 10% of the annual consumption is contaminated at the maximum levels

  18. Breast Reference Set Application: Karen Abbott- University of Arkansas (2013) — EDRN Public Portal

    Science.gov (United States)

    We are evaluating whether detection of a tumor-specific N-linked glycosylation known as B 1,6 branched N-glycan present on the glycoprotein periostin in breast cancer will be useful as a new biomarker for the detection of breast cancer in patient plasma and serum. We have completed an initial study using samples with known inavasive ductal breast carcinoma diagnosis and the results look very promising. Therefore, we would like to proceed with our analysis of this potential biomarker for breast cancer diagnosis by analyzing the blinded samples in breast reference set 1.

  19. A deep level set method for image segmentation

    OpenAIRE

    Tang, Min; Valipour, Sepehr; Zhang, Zichen Vincent; Cobzas, Dana; MartinJagersand

    2017-01-01

    This paper proposes a novel image segmentation approachthat integrates fully convolutional networks (FCNs) with a level setmodel. Compared with a FCN, the integrated method can incorporatesmoothing and prior information to achieve an accurate segmentation.Furthermore, different than using the level set model as a post-processingtool, we integrate it into the training phase to fine-tune the FCN. Thisallows the use of unlabeled data during training in a semi-supervisedsetting. Using two types o...

  20. A Level Set Discontinuous Galerkin Method for Free Surface Flows

    DEFF Research Database (Denmark)

    Grooss, Jesper; Hesthaven, Jan

    2006-01-01

    We present a discontinuous Galerkin method on a fully unstructured grid for the modeling of unsteady incompressible fluid flows with free surfaces. The surface is modeled by embedding and represented by a levelset. We discuss the discretization of the flow equations and the level set equation...

  1. Level Sets and Voronoi based Feature Extraction from any Imagery

    DEFF Research Database (Denmark)

    Sharma, O.; Anton, François; Mioc, Darka

    2012-01-01

    Polygon features are of interest in many GEOProcessing applications like shoreline mapping, boundary delineation, change detection, etc. This paper presents a unique new GPU-based methodology to automate feature extraction combining level sets, or mean shift based segmentation together with Voron...

  2. Level set methods for inverse scattering—some recent developments

    International Nuclear Information System (INIS)

    Dorn, Oliver; Lesselier, Dominique

    2009-01-01

    We give an update on recent techniques which use a level set representation of shapes for solving inverse scattering problems, completing in that matter the exposition made in (Dorn and Lesselier 2006 Inverse Problems 22 R67) and (Dorn and Lesselier 2007 Deformable Models (New York: Springer) pp 61–90), and bringing it closer to the current state of the art

  3. Structural level set inversion for microwave breast screening

    International Nuclear Information System (INIS)

    Irishina, Natalia; Álvarez, Diego; Dorn, Oliver; Moscoso, Miguel

    2010-01-01

    We present a new inversion strategy for the early detection of breast cancer from microwave data which is based on a new multiphase level set technique. This novel structural inversion method uses a modification of the color level set technique adapted to the specific situation of structural breast imaging taking into account the high complexity of the breast tissue. We only use data of a few microwave frequencies for detecting the tumors hidden in this complex structure. Three level set functions are employed for describing four different types of breast tissue, where each of these four regions is allowed to have a complicated topology and to have an interior structure which needs to be estimated from the data simultaneously with the region interfaces. The algorithm consists of several stages of increasing complexity. In each stage more details about the anatomical structure of the breast interior is incorporated into the inversion model. The synthetic breast models which are used for creating simulated data are based on real MRI images of the breast and are therefore quite realistic. Our results demonstrate the potential and feasibility of the proposed level set technique for detecting, locating and characterizing a small tumor in its early stage of development embedded in such a realistic breast model. Both the data acquisition simulation and the inversion are carried out in 2D

  4. Level-Set Methodology on Adaptive Octree Grids

    Science.gov (United States)

    Gibou, Frederic; Guittet, Arthur; Mirzadeh, Mohammad; Theillard, Maxime

    2017-11-01

    Numerical simulations of interfacial problems in fluids require a methodology capable of tracking surfaces that can undergo changes in topology and capable to imposing jump boundary conditions in a sharp manner. In this talk, we will discuss recent advances in the level-set framework, in particular one that is based on adaptive grids.

  5. A Memory and Computation Efficient Sparse Level-Set Method

    NARCIS (Netherlands)

    Laan, Wladimir J. van der; Jalba, Andrei C.; Roerdink, Jos B.T.M.

    Since its introduction, the level set method has become the favorite technique for capturing and tracking moving interfaces, and found applications in a wide variety of scientific fields. In this paper we present efficient data structures and algorithms for tracking dynamic interfaces through the

  6. Discretisation Schemes for Level Sets of Planar Gaussian Fields

    Science.gov (United States)

    Beliaev, D.; Muirhead, S.

    2018-01-01

    Smooth random Gaussian functions play an important role in mathematical physics, a main example being the random plane wave model conjectured by Berry to give a universal description of high-energy eigenfunctions of the Laplacian on generic compact manifolds. Our work is motivated by questions about the geometry of such random functions, in particular relating to the structure of their nodal and level sets. We study four discretisation schemes that extract information about level sets of planar Gaussian fields. Each scheme recovers information up to a different level of precision, and each requires a maximum mesh-size in order to be valid with high probability. The first two schemes are generalisations and enhancements of similar schemes that have appeared in the literature (Beffara and Gayet in Publ Math IHES, 2017. https://doi.org/10.1007/s10240-017-0093-0; Mischaikow and Wanner in Ann Appl Probab 17:980-1018, 2007); these give complete topological information about the level sets on either a local or global scale. As an application, we improve the results in Beffara and Gayet (2017) on Russo-Seymour-Welsh estimates for the nodal set of positively-correlated planar Gaussian fields. The third and fourth schemes are, to the best of our knowledge, completely new. The third scheme is specific to the nodal set of the random plane wave, and provides global topological information about the nodal set up to `visible ambiguities'. The fourth scheme gives a way to approximate the mean number of excursion domains of planar Gaussian fields.

  7. Development of сertified reference materials set for opened porosity of solid substances and materials (imitators

    Directory of Open Access Journals (Sweden)

    E. P. Sobina

    2016-01-01

    Full Text Available The article deals with data of research for development of certified reference materials set for opened porosity of solid substances and materials (imitators (OPTB SO UNIIM Set Certified Reference Materials GSO 10583-2015. The certified values of opened porosity of metal cylinders were established by the method of hydrostatic weighing before and after boring of holes in. The certified reference materials are intended for calibration and verification of measuring instruments of opened porosity, based on the Boyle - Mariotte's law.

  8. Gradient augmented level set method for phase change simulations

    Science.gov (United States)

    Anumolu, Lakshman; Trujillo, Mario F.

    2018-01-01

    A numerical method for the simulation of two-phase flow with phase change based on the Gradient-Augmented-Level-set (GALS) strategy is presented. Sharp capturing of the vaporization process is enabled by: i) identification of the vapor-liquid interface, Γ (t), at the subgrid level, ii) discontinuous treatment of thermal physical properties (except for μ), and iii) enforcement of mass, momentum, and energy jump conditions, where the gradients of the dependent variables are obtained at Γ (t) and are consistent with their analytical expression, i.e. no local averaging is applied. Treatment of the jump in velocity and pressure at Γ (t) is achieved using the Ghost Fluid Method. The solution of the energy equation employs the sub-grid knowledge of Γ (t) to discretize the temperature Laplacian using second-order one-sided differences, i.e. the numerical stencil completely resides within each respective phase. To carefully evaluate the benefits or disadvantages of the GALS approach, the standard level set method is implemented and compared against the GALS predictions. The results show the expected trend that interface identification and transport are predicted noticeably better with GALS over the standard level set. This benefit carries over to the prediction of the Laplacian and temperature gradients in the neighborhood of the interface, which are directly linked to the calculation of the vaporization rate. However, when combining the calculation of interface transport and reinitialization with two-phase momentum and energy, the benefits of GALS are to some extent neutralized, and the causes for this behavior are identified and analyzed. Overall the additional computational costs associated with GALS are almost the same as those using the standard level set technique.

  9. Level sets and extrema of random processes and fields

    CERN Document Server

    Azais, Jean-Marc

    2009-01-01

    A timely and comprehensive treatment of random field theory with applications across diverse areas of study Level Sets and Extrema of Random Processes and Fields discusses how to understand the properties of the level sets of paths as well as how to compute the probability distribution of its extremal values, which are two general classes of problems that arise in the study of random processes and fields and in related applications. This book provides a unified and accessible approach to these two topics and their relationship to classical theory and Gaussian processes and fields, and the most modern research findings are also discussed. The authors begin with an introduction to the basic concepts of stochastic processes, including a modern review of Gaussian fields and their classical inequalities. Subsequent chapters are devoted to Rice formulas, regularity properties, and recent results on the tails of the distribution of the maximum. Finally, applications of random fields to various areas of mathematics a...

  10. Skull defect reconstruction based on a new hybrid level set.

    Science.gov (United States)

    Zhang, Ziqun; Zhang, Ran; Song, Zhijian

    2014-01-01

    Skull defect reconstruction is an important aspect of surgical repair. Historically, a skull defect prosthesis was created by the mirroring technique, surface fitting, or formed templates. These methods are not based on the anatomy of the individual patient's skull, and therefore, the prosthesis cannot precisely correct the defect. This study presented a new hybrid level set model, taking into account both the global optimization region information and the local accuracy edge information, while avoiding re-initialization during the evolution of the level set function. Based on the new method, a skull defect was reconstructed, and the skull prosthesis was produced by rapid prototyping technology. This resulted in a skull defect prosthesis that well matched the skull defect with excellent individual adaptation.

  11. Level-set techniques for facies identification in reservoir modeling

    Science.gov (United States)

    Iglesias, Marco A.; McLaughlin, Dennis

    2011-03-01

    In this paper we investigate the application of level-set techniques for facies identification in reservoir models. The identification of facies is a geometrical inverse ill-posed problem that we formulate in terms of shape optimization. The goal is to find a region (a geologic facies) that minimizes the misfit between predicted and measured data from an oil-water reservoir. In order to address the shape optimization problem, we present a novel application of the level-set iterative framework developed by Burger in (2002 Interfaces Free Bound. 5 301-29 2004 Inverse Problems 20 259-82) for inverse obstacle problems. The optimization is constrained by (the reservoir model) a nonlinear large-scale system of PDEs that describes the reservoir dynamics. We reformulate this reservoir model in a weak (integral) form whose shape derivative can be formally computed from standard results of shape calculus. At each iteration of the scheme, the current estimate of the shape derivative is utilized to define a velocity in the level-set equation. The proper selection of this velocity ensures that the new shape decreases the cost functional. We present results of facies identification where the velocity is computed with the gradient-based (GB) approach of Burger (2002) and the Levenberg-Marquardt (LM) technique of Burger (2004). While an adjoint formulation allows the straightforward application of the GB approach, the LM technique requires the computation of the large-scale Karush-Kuhn-Tucker system that arises at each iteration of the scheme. We efficiently solve this system by means of the representer method. We present some synthetic experiments to show and compare the capabilities and limitations of the proposed implementations of level-set techniques for the identification of geologic facies.

  12. Level-set techniques for facies identification in reservoir modeling

    International Nuclear Information System (INIS)

    Iglesias, Marco A; McLaughlin, Dennis

    2011-01-01

    In this paper we investigate the application of level-set techniques for facies identification in reservoir models. The identification of facies is a geometrical inverse ill-posed problem that we formulate in terms of shape optimization. The goal is to find a region (a geologic facies) that minimizes the misfit between predicted and measured data from an oil–water reservoir. In order to address the shape optimization problem, we present a novel application of the level-set iterative framework developed by Burger in (2002 Interfaces Free Bound. 5 301–29; 2004 Inverse Problems 20 259–82) for inverse obstacle problems. The optimization is constrained by (the reservoir model) a nonlinear large-scale system of PDEs that describes the reservoir dynamics. We reformulate this reservoir model in a weak (integral) form whose shape derivative can be formally computed from standard results of shape calculus. At each iteration of the scheme, the current estimate of the shape derivative is utilized to define a velocity in the level-set equation. The proper selection of this velocity ensures that the new shape decreases the cost functional. We present results of facies identification where the velocity is computed with the gradient-based (GB) approach of Burger (2002) and the Levenberg–Marquardt (LM) technique of Burger (2004). While an adjoint formulation allows the straightforward application of the GB approach, the LM technique requires the computation of the large-scale Karush–Kuhn–Tucker system that arises at each iteration of the scheme. We efficiently solve this system by means of the representer method. We present some synthetic experiments to show and compare the capabilities and limitations of the proposed implementations of level-set techniques for the identification of geologic facies

  13. A new level set model for cell image segmentation

    Science.gov (United States)

    Ma, Jing-Feng; Hou, Kai; Bao, Shang-Lian; Chen, Chun

    2011-02-01

    In this paper we first determine three phases of cell images: background, cytoplasm and nucleolus according to the general physical characteristics of cell images, and then develop a variational model, based on these characteristics, to segment nucleolus and cytoplasm from their relatively complicated backgrounds. In the meantime, the preprocessing obtained information of cell images using the OTSU algorithm is used to initialize the level set function in the model, which can speed up the segmentation and present satisfactory results in cell image processing.

  14. Level Set Approach to Anisotropic Wet Etching of Silicon

    Directory of Open Access Journals (Sweden)

    Branislav Radjenović

    2010-05-01

    Full Text Available In this paper a methodology for the three dimensional (3D modeling and simulation of the profile evolution during anisotropic wet etching of silicon based on the level set method is presented. Etching rate anisotropy in silicon is modeled taking into account full silicon symmetry properties, by means of the interpolation technique using experimentally obtained values for the etching rates along thirteen principal and high index directions in KOH solutions. The resulting level set equations are solved using an open source implementation of the sparse field method (ITK library, developed in medical image processing community, extended for the case of non-convex Hamiltonians. Simulation results for some interesting initial 3D shapes, as well as some more practical examples illustrating anisotropic etching simulation in the presence of masks (simple square aperture mask, convex corner undercutting and convex corner compensation, formation of suspended structures are shown also. The obtained results show that level set method can be used as an effective tool for wet etching process modeling, and that is a viable alternative to the Cellular Automata method which now prevails in the simulations of the wet etching process.

  15. Dosimetric methodology and reference system for diagnostic level X radiation

    International Nuclear Information System (INIS)

    Potiens, Maria da Penha Albuquerque

    1999-01-01

    Several methodologies for the calibration of diagnostic radiology instruments were developed and established at the Calibration Laboratory of IPEN. These established radiation qualities are recommended by international standards. The methods may be used in the calibration procedures of survey meters used in radiation protection measurements (scattered radiation), instruments used in direct beams (attenuated and non attenuated beams) and quality control instruments. A reference system was proposed using two identical ionization chambers developed at IPEN. They differ only by the collecting electrode material, one of aluminium and the other of graphite. The different energetic dependence of the chamber's response provided a ratio related to the tube potential. The variation of only 0.28%, from 14.3 to 111 keV, on the energetic dependence of the graphite electrode chamber, provided the possibility of air kerma rate determination in the studied radiation beams. (author)

  16. Liver Rapid Reference Set Application: Hemken - Abbott (2015) — EDRN Public Portal

    Science.gov (United States)

    The aim for this testing is to find a small panel of biomarkers (n=2-5) that can be tested on the Abbott ARCHITECT automated immunoassay platform for the early detection of hepatocellular carcinoma (HCC). This panel of biomarkers should perform significantly better than alpha-fetoprotein (AFP) alone based on multivariate statistical analysis. This testing of the EDRN reference set will help expedite the selection of a small panel of ARCHITECT biomarkers for the early detection of HCC. The panel of ARCHITECT biomarkers Abbott plans to test include: AFP, protein induced by vitamin K absence or antagonist-II (PIVKA-II), golgi protein 73 (GP73), hepatocellular growth factor (HGF), dipeptidyl peptidase 4 (DPP4) and DPP4/seprase (surface expressed protease) heterodimer hybrid. PIVKA-II is abnormal des-carboxylated prothrombin (DCP) present in vitamin K deficiency.

  17. Reevaluation of steam generator level trip set point

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Yoon Sub; Soh, Dong Sub; Kim, Sung Oh; Jung, Se Won; Sung, Kang Sik; Lee, Joon [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-06-01

    The reactor trip by the low level of steam generator water accounts for a substantial portion of reactor scrams in a nuclear plant and the feasibility of modification of the steam generator water level trip system of YGN 1/2 was evaluated in this study. The study revealed removal of the reactor trip function from the SG water level trip system is not possible because of plant safety but relaxation of the trip set point by 9 % is feasible. The set point relaxation requires drilling of new holes for level measurement to operating steam generators. Characteristics of negative neutron flux rate trip and reactor trip were also reviewed as an additional work. Since the purpose of the trip system modification for reduction of a reactor scram frequency is not to satisfy legal requirements but to improve plant performance and the modification yields positive and negative aspects, the decision of actual modification needs to be made based on the results of this study and also the policy of a plant owner. 37 figs, 6 tabs, 14 refs. (Author).

  18. Selection and validation of a set of reliable reference genes for quantitative sod gene expression analysis in C. elegans

    Directory of Open Access Journals (Sweden)

    Vandesompele Jo

    2008-01-01

    Full Text Available Abstract Background In the nematode Caenorhabditis elegans the conserved Ins/IGF-1 signaling pathway regulates many biological processes including life span, stress response, dauer diapause and metabolism. Detection of differentially expressed genes may contribute to a better understanding of the mechanism by which the Ins/IGF-1 signaling pathway regulates these processes. Appropriate normalization is an essential prerequisite for obtaining accurate and reproducible quantification of gene expression levels. The aim of this study was to establish a reliable set of reference genes for gene expression analysis in C. elegans. Results Real-time quantitative PCR was used to evaluate the expression stability of 12 candidate reference genes (act-1, ama-1, cdc-42, csq-1, eif-3.C, mdh-1, gpd-2, pmp-3, tba-1, Y45F10D.4, rgs-6 and unc-16 in wild-type, three Ins/IGF-1 pathway mutants, dauers and L3 stage larvae. After geNorm analysis, cdc-42, pmp-3 and Y45F10D.4 showed the most stable expression pattern and were used to normalize 5 sod expression levels. Significant differences in mRNA levels were observed for sod-1 and sod-3 in daf-2 relative to wild-type animals, whereas in dauers sod-1, sod-3, sod-4 and sod-5 are differentially expressed relative to third stage larvae. Conclusion Our findings emphasize the importance of accurate normalization using stably expressed reference genes. The methodology used in this study is generally applicable to reliably quantify gene expression levels in the nematode C. elegans using quantitative PCR.

  19. Level set method for image segmentation based on moment competition

    Science.gov (United States)

    Min, Hai; Wang, Xiao-Feng; Huang, De-Shuang; Jin, Jing; Wang, Hong-Zhi; Li, Hai

    2015-05-01

    We propose a level set method for image segmentation which introduces the moment competition and weakly supervised information into the energy functional construction. Different from the region-based level set methods which use force competition, the moment competition is adopted to drive the contour evolution. Here, a so-called three-point labeling scheme is proposed to manually label three independent points (weakly supervised information) on the image. Then the intensity differences between the three points and the unlabeled pixels are used to construct the force arms for each image pixel. The corresponding force is generated from the global statistical information of a region-based method and weighted by the force arm. As a result, the moment can be constructed and incorporated into the energy functional to drive the evolving contour to approach the object boundary. In our method, the force arm can take full advantage of the three-point labeling scheme to constrain the moment competition. Additionally, the global statistical information and weakly supervised information are successfully integrated, which makes the proposed method more robust than traditional methods for initial contour placement and parameter setting. Experimental results with performance analysis also show the superiority of the proposed method on segmenting different types of complicated images, such as noisy images, three-phase images, images with intensity inhomogeneity, and texture images.

  20. A variant reference data set for the Africanized honeybee, Apis mellifera.

    Science.gov (United States)

    Kadri, Samir M; Harpur, Brock A; Orsi, Ricardo O; Zayed, Amro

    2016-11-08

    The Africanized honeybee (AHB) is a population of Apis mellifera found in the Americas. AHBs originated in 1956 in Rio Clara, Brazil where imported African A. m. scutellata escaped and hybridized with local populations of European A. mellifera. Africanized populations can now be found from Northern Argentina to the Southern United States. AHBs-often referred to as 'Killer Bees'- are a major concern to the beekeeping industry as well as a model for the evolutionary genetics of colony defence. We performed high coverage pooled-resequencing of 360 diploid workers from 30 Brazilian AHB colonies using Illumina Hi-Seq (150 bp PE). This yielded a high density SNP data set with an average read depth at each site of 20.25 reads. With 3,606,720 SNPs and 155,336 SNPs within 11,365 genes, this data set is the largest genomic resource available for AHBs and will enable high-resolution studies of the population dynamics, evolution, and genetics of this successful biological invader, in addition to facilitating the development of SNP-based tools for identifying AHBs.

  1. A reference data set for validating vapor pressure measurement techniques: homologous series of polyethylene glycols

    Science.gov (United States)

    Krieger, Ulrich K.; Siegrist, Franziska; Marcolli, Claudia; Emanuelsson, Eva U.; Gøbel, Freya M.; Bilde, Merete; Marsh, Aleksandra; Reid, Jonathan P.; Huisman, Andrew J.; Riipinen, Ilona; Hyttinen, Noora; Myllys, Nanna; Kurtén, Theo; Bannan, Thomas; Percival, Carl J.; Topping, David

    2018-01-01

    To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well-established saturation vapor pressures. However, vapor pressures of semivolatile and low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of 2. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem, we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H - (O - CH2 - CH2)n - OH) for n = 3 to n = 8 ranging in vapor pressure at 298 K from 10-7 to 5×10-2 Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows outlying data to be rejected more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressure values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass

  2. Evaluating healthcare priority setting at the meso level: A thematic review of empirical literature

    Science.gov (United States)

    Waithaka, Dennis; Tsofa, Benjamin; Barasa, Edwine

    2018-01-01

    Background: Decentralization of health systems has made sub-national/regional healthcare systems the backbone of healthcare delivery. These regions are tasked with the difficult responsibility of determining healthcare priorities and resource allocation amidst scarce resources. We aimed to review empirical literature that evaluated priority setting practice at the meso (sub-national) level of health systems. Methods: We systematically searched PubMed, ScienceDirect and Google scholar databases and supplemented these with manual searching for relevant studies, based on the reference list of selected papers. We only included empirical studies that described and evaluated, or those that only evaluated priority setting practice at the meso-level. A total of 16 papers were identified from LMICs and HICs. We analyzed data from the selected papers by thematic review. Results: Few studies used systematic priority setting processes, and all but one were from HICs. Both formal and informal criteria are used in priority-setting, however, informal criteria appear to be more perverse in LMICs compared to HICs. The priority setting process at the meso-level is a top-down approach with minimal involvement of the community. Accountability for reasonableness was the most common evaluative framework as it was used in 12 of the 16 studies. Efficiency, reallocation of resources and options for service delivery redesign were the most common outcome measures used to evaluate priority setting. Limitations: Our study was limited by the fact that there are very few empirical studies that have evaluated priority setting at the meso-level and there is likelihood that we did not capture all the studies. Conclusions: Improving priority setting practices at the meso level is crucial to strengthening health systems. This can be achieved through incorporating and adapting systematic priority setting processes and frameworks to the context where used, and making considerations of both process

  3. A new level set model for cell image segmentation

    International Nuclear Information System (INIS)

    Ma Jing-Feng; Chen Chun; Hou Kai; Bao Shang-Lian

    2011-01-01

    In this paper we first determine three phases of cell images: background, cytoplasm and nucleolus according to the general physical characteristics of cell images, and then develop a variational model, based on these characteristics, to segment nucleolus and cytoplasm from their relatively complicated backgrounds. In the meantime, the preprocessing obtained information of cell images using the OTSU algorithm is used to initialize the level set function in the model, which can speed up the segmentation and present satisfactory results in cell image processing. (cross-disciplinary physics and related areas of science and technology)

  4. French diagnostic reference levels in diagnostic radiology, computed tomography and nuclear medicine: 2004-2008 Review

    International Nuclear Information System (INIS)

    Roch, P.; Aubert, B.

    2013-01-01

    After 5 y of collecting data on diagnostic reference levels (DRLs), the Nuclear Safety and Radiation Protection French Inst. (IRSN) presents the analyses of this data. The analyses of the collected data for radiology, computed tomography (CT) and nuclear medicine allow IRSN to estimate the level of regulatory application by health professionals and the representativeness of current DRL in terms of relevant examinations, dosimetric quantities, numerical values and patient morphologies. Since 2004, the involvement of professionals has highly increased, especially in nuclear medicine, followed by CT and then by radiology. Analyses show some discordance between regulatory examinations and clinical practice. Some of the dosimetric quantities used for the DRL setting are insufficient or not relevant enough, and some numerical values should also be reviewed. On the basis of these findings, IRSN formulates recommendations to update regulatory DRL with current and relevant examination lists, dosimetric quantities and numerical values. (authors)

  5. Google Sets, Google Suggest, and Google Search History: Three More Tools for the Reference Librarian's Bag of Tricks

    OpenAIRE

    Cirasella, Jill

    2008-01-01

    This article examines the features, quirks, and uses of Google Sets, Google Suggest, and Google Search History and argues that these three lesser-known Google tools warrant inclusion in the resourceful reference librarian’s bag of tricks.

  6. Setting Healthcare Priorities at the Macro and Meso Levels: A Framework for Evaluation.

    Science.gov (United States)

    Barasa, Edwine W; Molyneux, Sassy; English, Mike; Cleary, Susan

    2015-09-16

    Priority setting in healthcare is a key determinant of health system performance. However, there is no widely accepted priority setting evaluation framework. We reviewed literature with the aim of developing and proposing a framework for the evaluation of macro and meso level healthcare priority setting practices. We systematically searched Econlit, PubMed, CINAHL, and EBSCOhost databases and supplemented this with searches in Google Scholar, relevant websites and reference lists of relevant papers. A total of 31 papers on evaluation of priority setting were identified. These were supplemented by broader theoretical literature related to evaluation of priority setting. A conceptual review of selected papers was undertaken. Based on a synthesis of the selected literature, we propose an evaluative framework that requires that priority setting practices at the macro and meso levels of the health system meet the following conditions: (1) Priority setting decisions should incorporate both efficiency and equity considerations as well as the following outcomes; (a) Stakeholder satisfaction, (b) Stakeholder understanding, (c) Shifted priorities (reallocation of resources), and (d) Implementation of decisions. (2) Priority setting processes should also meet the procedural conditions of (a) Stakeholder engagement, (b) Stakeholder empowerment, (c) Transparency, (d) Use of evidence, (e) Revisions, (f) Enforcement, and (g) Being grounded on community values. Available frameworks for the evaluation of priority setting are mostly grounded on procedural requirements, while few have included outcome requirements. There is, however, increasing recognition of the need to incorporate both consequential and procedural considerations in priority setting practices. In this review, we adapt an integrative approach to develop and propose a framework for the evaluation of priority setting practices at the macro and meso levels that draws from these complementary schools of thought. © 2015

  7. Setting Healthcare Priorities at the Macro and Meso Levels: A Framework for Evaluation

    Science.gov (United States)

    Barasa, Edwine W.; Molyneux, Sassy; English, Mike; Cleary, Susan

    2015-01-01

    Background: Priority setting in healthcare is a key determinant of health system performance. However, there is no widely accepted priority setting evaluation framework. We reviewed literature with the aim of developing and proposing a framework for the evaluation of macro and meso level healthcare priority setting practices. Methods: We systematically searched Econlit, PubMed, CINAHL, and EBSCOhost databases and supplemented this with searches in Google Scholar, relevant websites and reference lists of relevant papers. A total of 31 papers on evaluation of priority setting were identified. These were supplemented by broader theoretical literature related to evaluation of priority setting. A conceptual review of selected papers was undertaken. Results: Based on a synthesis of the selected literature, we propose an evaluative framework that requires that priority setting practices at the macro and meso levels of the health system meet the following conditions: (1) Priority setting decisions should incorporate both efficiency and equity considerations as well as the following outcomes; (a) Stakeholder satisfaction, (b) Stakeholder understanding, (c) Shifted priorities (reallocation of resources), and (d) Implementation of decisions. (2) Priority setting processes should also meet the procedural conditions of (a) Stakeholder engagement, (b) Stakeholder empowerment, (c) Transparency, (d) Use of evidence, (e) Revisions, (f) Enforcement, and (g) Being grounded on community values. Conclusion: Available frameworks for the evaluation of priority setting are mostly grounded on procedural requirements, while few have included outcome requirements. There is, however, increasing recognition of the need to incorporate both consequential and procedural considerations in priority setting practices. In this review, we adapt an integrative approach to develop and propose a framework for the evaluation of priority setting practices at the macro and meso levels that draws from these

  8. Setting Healthcare Priorities at the Macro and Meso Levels: A Framework for Evaluation

    Directory of Open Access Journals (Sweden)

    Edwine W. Barasa

    2015-11-01

    Full Text Available Background Priority setting in healthcare is a key determinant of health system performance. However, there is no widely accepted priority setting evaluation framework. We reviewed literature with the aim of developing and proposing a framework for the evaluation of macro and meso level healthcare priority setting practices. Methods We systematically searched Econlit, PubMed, CINAHL, and EBSCOhost databases and supplemented this with searches in Google Scholar, relevant websites and reference lists of relevant papers. A total of 31 papers on evaluation of priority setting were identified. These were supplemented by broader theoretical literature related to evaluation of priority setting. A conceptual review of selected papers was undertaken. Results Based on a synthesis of the selected literature, we propose an evaluative framework that requires that priority setting practices at the macro and meso levels of the health system meet the following conditions: (1 Priority setting decisions should incorporate both efficiency and equity considerations as well as the following outcomes; (a Stakeholder satisfaction, (b Stakeholder understanding, (c Shifted priorities (reallocation of resources, and (d Implementation of decisions. (2 Priority setting processes should also meet the procedural conditions of (a Stakeholder engagement, (b Stakeholder empowerment, (c Transparency, (d Use of evidence, (e Revisions, (f Enforcement, and (g Being grounded on community values. Conclusion Available frameworks for the evaluation of priority setting are mostly grounded on procedural requirements, while few have included outcome requirements. There is, however, increasing recognition of the need to incorporate both consequential and procedural considerations in priority setting practices. In this review, we adapt an integrative approach to develop and propose a framework for the evaluation of priority setting practices at the macro and meso levels that draws from

  9. SU-F-J-180: A Reference Data Set for Testing Two Dimension Registration Algorithms

    International Nuclear Information System (INIS)

    Dankwa, A; Castillo, E; Guerrero, T

    2016-01-01

    Purpose: To create and characterize a reference data set for testing image registration algorithms that transform portal image (PI) to digitally reconstructed radiograph (DRR). Methods: Anterior-posterior (AP) and Lateral (LAT) projection and DRR image pairs from nine cases representing four different anatomical sites (head and neck, thoracic, abdominal, and pelvis) were selected for this study. Five experts will perform manual registration by placing landmarks points (LMPs) on the DRR and finding their corresponding points on the PI using computer assisted manual point selection tool (CAMPST), a custom-made MATLAB software tool developed in house. The landmark selection process will be repeated on both the PI and the DRR in order to characterize inter- and -intra observer variations associated with the point selection process. Inter and an intra observer variation in LMPs was done using Bland-Altman (B&A) analysis and one-way analysis of variance. We set our limit such that the absolute value of the mean difference between the readings should not exceed 3mm. Later on in this project we will test different two dimension (2D) image registration algorithms and quantify the uncertainty associated with their registration. Results: Using one-way analysis of variance (ANOVA) there was no variations within the readers. When Bland-Altman analysis was used the variation within the readers was acceptable. The variation was higher in the PI compared to the DRR.ConclusionThe variation seen for the PI is because although the PI has a much better spatial resolution the poor resolution on the DRR makes it difficult to locate the actual corresponding anatomical feature on the PI. We hope this becomes more evident when all the readers complete the point selection. The reason for quantifying inter- and -intra observer variation tells us to what degree of accuracy a manual registration can be done. Research supported by William Beaumont Hospital Research Start Up Fund.

  10. SU-F-J-180: A Reference Data Set for Testing Two Dimension Registration Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Dankwa, A; Castillo, E; Guerrero, T [William Beaumont Hospital, Rochester Hills, MI (United States)

    2016-06-15

    Purpose: To create and characterize a reference data set for testing image registration algorithms that transform portal image (PI) to digitally reconstructed radiograph (DRR). Methods: Anterior-posterior (AP) and Lateral (LAT) projection and DRR image pairs from nine cases representing four different anatomical sites (head and neck, thoracic, abdominal, and pelvis) were selected for this study. Five experts will perform manual registration by placing landmarks points (LMPs) on the DRR and finding their corresponding points on the PI using computer assisted manual point selection tool (CAMPST), a custom-made MATLAB software tool developed in house. The landmark selection process will be repeated on both the PI and the DRR in order to characterize inter- and -intra observer variations associated with the point selection process. Inter and an intra observer variation in LMPs was done using Bland-Altman (B&A) analysis and one-way analysis of variance. We set our limit such that the absolute value of the mean difference between the readings should not exceed 3mm. Later on in this project we will test different two dimension (2D) image registration algorithms and quantify the uncertainty associated with their registration. Results: Using one-way analysis of variance (ANOVA) there was no variations within the readers. When Bland-Altman analysis was used the variation within the readers was acceptable. The variation was higher in the PI compared to the DRR.ConclusionThe variation seen for the PI is because although the PI has a much better spatial resolution the poor resolution on the DRR makes it difficult to locate the actual corresponding anatomical feature on the PI. We hope this becomes more evident when all the readers complete the point selection. The reason for quantifying inter- and -intra observer variation tells us to what degree of accuracy a manual registration can be done. Research supported by William Beaumont Hospital Research Start Up Fund.

  11. Liver Full Reference Set Application: Hiro Yamada - Wako (2011) — EDRN Public Portal

    Science.gov (United States)

    Wako has received new 510(k) clearance for Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein (AFP-L3) and Des-gamma-carboxy prothrombin (DCP) tests on an innovative μTASWako i30 analyzer from FDA. The AFP-L3 and DCP assayed on an older platform LiBASys have been cleared with indication of use for risk assessment of hepatocellular carcinoma (HCC) in patient at risk for the liver malignancy. Wako believes that early detection of HCC is critical for improving HCC patient outcome. Therefore, Wako is currently seeking collaborative opportunities to retrospectively measure clinical samples using the AFP-L3 and DCP for further determining of effectiveness of the HCC biomarkers in early detection which are collected prospectively during HCC surveillance. The Reference Sample Set in the EDRN biorepository are well characterized and studied. Access to these samples would allow Wako to quickly determine the clinical effectiveness of AFP-L3 and DCP in detecting early HCC

  12. Giving Context to the Physician Competency Reference Set: Adapting to the Needs of Diverse Populations

    Science.gov (United States)

    Eckstrand, Kristen L.; Potter, Jennifer; Bayer, Carey Roth; Englander, Robert

    2016-01-01

    Delineating the requisite competencies of a 21st-century physician is the first step in the paradigm shift to competency-based medical education. Over the past two decades, more than 150 lists of competencies have emerged. In a synthesis of these lists, the Physician Competency Reference Set (PCRS) provided a unifying framework of competencies that define the general physician. The PCRS is not context or population specific; however, competently caring for certain underrepresented populations or specific medical conditions can require more specific context. Previously developed competency lists describing care for these populations have been disconnected from an overarching competency framework, limiting their uptake. To address this gap, the Association of American Medical Colleges Advisory Committee on Sexual Orientation, Gender Identity, and Sex Development adapted the PCRS by adding context- and content-specific qualifying statements to existing PCRS competencies to better meet the needs of diverse patient populations. This Article describes the committee’s process in developing these qualifiers of competence. To facilitate widespread adoption of the contextualized competencies in U.S. medical schools, the committee used an established competency framework to develop qualifiers of competence to improve the health of individuals who are lesbian, gay, bisexual, transgender; gender nonconforming; or born with differences in sexual development. This process can be applied to other underrepresented populations or medical conditions, ensuring that relevant topics are included in medical education and, ultimately, health care outcomes are improved for all patients inclusive of diversity, background, and ability. PMID:26796092

  13. Roadmap to a mutually consistent set of offshore vertical reference frames

    NARCIS (Netherlands)

    Slobbe, D.C.

    2013-01-01

    This thesis presents a combined approach for the realization of the (quasi-)geoid as a height reference surface and the vertical reference surface at sea (chart datum). This approach, specifically designed for shallow seas and coastal waters, provides the relation between the two vertical reference

  14. Surface-to-surface registration using level sets

    DEFF Research Database (Denmark)

    Hansen, Mads Fogtmann; Erbou, Søren G.; Vester-Christensen, Martin

    2007-01-01

    This paper presents a general approach for surface-to-surface registration (S2SR) with the Euclidean metric using signed distance maps. In addition, the method is symmetric such that the registration of a shape A to a shape B is identical to the registration of the shape B to the shape A. The S2SR...... problem can be approximated by the image registration (IR) problem of the signed distance maps (SDMs) of the surfaces confined to some narrow band. By shrinking the narrow bands around the zero level sets the solution to the IR problem converges towards the S2SR problem. It is our hypothesis...... that this approach is more robust and less prone to fall into local minima than ordinary surface-to-surface registration. The IR problem is solved using the inverse compositional algorithm. In this paper, a set of 40 pelvic bones of Duroc pigs are registered to each other w.r.t. the Euclidean transformation...

  15. A New Dual-purpose Quality Control Dosimetry Protocol for Diagnostic Reference-level Determination in Computed Tomography.

    Science.gov (United States)

    Sohrabi, Mehdi; Parsi, Masoumeh; Sina, Sedigheh

    2018-05-17

    A diagnostic reference level is an advisory dose level set by a regulatory authority in a country as an efficient criterion for protection of patients from unwanted medical exposure. In computed tomography, the direct dose measurement and data collection methods are commonly applied for determination of diagnostic reference levels. Recently, a new quality-control-based dose survey method was proposed by the authors to simplify the diagnostic reference-level determination using a retrospective quality control database usually available at a regulatory authority in a country. In line with such a development, a prospective dual-purpose quality control dosimetry protocol is proposed for determination of diagnostic reference levels in a country, which can be simply applied by quality control service providers. This new proposed method was applied to five computed tomography scanners in Shiraz, Iran, and diagnostic reference levels for head, abdomen/pelvis, sinus, chest, and lumbar spine examinations were determined. The results were compared to those obtained by the data collection and quality-control-based dose survey methods, carried out in parallel in this study, and were found to agree well within approximately 6%. This is highly acceptable for quality-control-based methods according to International Atomic Energy Agency tolerance levels (±20%).

  16. Forget the Desk Job: Current Roles and Responsibilities in Entry-Level Reference Job Advertisements

    Science.gov (United States)

    Detmering, Robert; Sproles, Claudene

    2012-01-01

    This study examines the evolving roles and responsibilities of entry-level academic reference positions, as stated in recent job advertisements posted on the American Library Association's JobLIST Web site and other sources. Findings from a content analysis of these advertisements indicate that current entry-level reference positions in academic…

  17. Alanine dosimetry at NPL - the development of a mailed reference dosimetry service at radiotherapy dose levels

    International Nuclear Information System (INIS)

    Sharpe, P.H.G.; Sephton, J.P.

    1999-01-01

    In this paper we describe the work that has been carried out at National Physical Laboratory (NPL) to develop a mailed alanine reference dosimetry service for radiotherapy dose levels. The service is based on alanine/paraffin wax dosimeters produced at NPL. Using a data analysis technique based on spectrum fitting, it has been possible to achieve a precision of dose measurement better than ±0.05 Gy (1σ). A phantom set has been developed for use in high energy photon beams, which enables simultaneous irradiation of alanine dosimeters and ionisation chambers in a well defined geometry. Studies in photon beams of energies between 60 Co and 20 MeV have shown no significant energy dependence (<1%) for alanine relative to dose determination using a graphite calorimeter. Work is underway to extend the service to electron beams, and preliminary results are presented on the direct calibration of alanine in electron beams using a graphite calorimeter. (author)

  18. Determination of Natural Levels of Radionuclides in Proposed Mushroom Reference Material (A Proficiency Test Exercise)

    International Nuclear Information System (INIS)

    Waheed, S.; Rahman, A.; Siddique, N.; Ahmad, S.; Zaidi, J.H.

    2006-08-01

    A proficiency test (PT) was organized within the framework of international Atomic Energy Agency (IAEA) project INT/1/054, entitled 'Preparation' of Reference Materials and Organization of Proficiency Test Rounds'. This exercise served to estimate the proficiency of the analytical laboratories from participating countries. This report presents the results of the proficiency test exercise on the proposed Mushroom Reference Material for the determination of natural levels of radionuclides. Laboratories from 6 different countries submitted data on the following three radionuclides: /sup 134/Cs, /sup 137/Cs, /sup 40/K. Results for /sup 134/Cs, 137/sup 137/Cs, and /sup 40/K in the mushroom reference material were reported by three or more participating laboratories and could be subjected to statistical evaluation. The original data of these raionuclides was subjected to a computer program 'Histo Vession 2.1' provided by IAEA. The four outlier tests i.e. Dixon, Grubbs, Skewness and Kurtosis were applied to the data sets. All values for these three radionuclides were accepted by the software. Consensus (overall) mean value, absolute standard deviation, relative standard deviation, standard error, median and range of values for these three radionuclides have been are obtained (at significance level 0.05). the consensus mean values and confidence intervals are given./sup 134/Cs: 4.4 Bq/kg (3.4-5.3 Bq/kg) /sup 137/Cs: 2899 Bq/kg (2740-3058 Bq/kg) /sup 40/K: 1136 Bq/kg (1046-1226 Bq/kg). (author)

  19. Cognitive functioning and adjudicative competence: defendants referred for neuropsychological evaluation in a psychiatric inpatient setting.

    Science.gov (United States)

    Arredondo, Beth C; Marcopulos, Bernice A; Brand, Jesse G; Campbell, Kristen T; Kent, Julie-Ann

    2017-11-01

    A paucity of peer-reviewed research exists regarding the relation between cognitive functioning and adjudicative competence, despite increasing awareness of cognitive deficits associated with serious mental illness. This retrospective study sought to add to and expand upon existing research by considering performance validity and court determinations of competence, when available. We compared demographic and cognitive variables of a group of defendants with presumed valid testing admitted to an inpatient psychiatric facility for evaluation of adjudicative competence and referred for neuropsychological evaluation (n = 45) and compared individuals determined by the evaluator and/or the court to be competent (n = 30) and incompetent (n = 15). Defendants who were incompetent were more likely to be diagnosed with a cognitive disorder, with a medium effect size. There was a difference in tests of immediate and delayed memory as measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), with medium to large effects, and high delayed memory scores were helpful in ruling out incompetence (Negative predictive power = 85.71%). These results provide support for the relationship between cognitive functioning and trial competence, particularly at high and low levels of performance.

  20. The establishment and use of dose reference levels in general paediatric radiology

    International Nuclear Information System (INIS)

    Marsden, P.J.; Hardwick, J.; Mencik, C.; McLaren, C.; Young, C.; Mashford, P.

    2001-01-01

    Diagnostic reference levels for general paediatric radiology have been established in terms of delivered exposure parameters rather than skin dose or dose-area product. With supporting measurements from equipment quality assurance and assumptions of standard patient sizes it was possible to derive reference levels in terms of entrance surface dose. This allowed comparison to be made with other published data. The reference levels for common examinations are presented for different age bands. There is a notable variation with patient age for some examinations which is not apparent in other published data. (author)

  1. Topology optimization of hyperelastic structures using a level set method

    Science.gov (United States)

    Chen, Feifei; Wang, Yiqiang; Wang, Michael Yu; Zhang, Y. F.

    2017-12-01

    Soft rubberlike materials, due to their inherent compliance, are finding widespread implementation in a variety of applications ranging from assistive wearable technologies to soft material robots. Structural design of such soft and rubbery materials necessitates the consideration of large nonlinear deformations and hyperelastic material models to accurately predict their mechanical behaviour. In this paper, we present an effective level set-based topology optimization method for the design of hyperelastic structures that undergo large deformations. The method incorporates both geometric and material nonlinearities where the strain and stress measures are defined within the total Lagrange framework and the hyperelasticity is characterized by the widely-adopted Mooney-Rivlin material model. A shape sensitivity analysis is carried out, in the strict sense of the material derivative, where the high-order terms involving the displacement gradient are retained to ensure the descent direction. As the design velocity enters into the shape derivative in terms of its gradient and divergence terms, we develop a discrete velocity selection strategy. The whole optimization implementation undergoes a two-step process, where the linear optimization is first performed and its optimized solution serves as the initial design for the subsequent nonlinear optimization. It turns out that this operation could efficiently alleviate the numerical instability and facilitate the optimization process. To demonstrate the validity and effectiveness of the proposed method, three compliance minimization problems are studied and their optimized solutions present significant mechanical benefits of incorporating the nonlinearities, in terms of remarkable enhancement in not only the structural stiffness but also the critical buckling load.

  2. Segmenting the Parotid Gland using Registration and Level Set Methods

    DEFF Research Database (Denmark)

    Hollensen, Christian; Hansen, Mads Fogtmann; Højgaard, Liselotte

    . The method was evaluated on a test set consisting of 8 corresponding data sets. The attained total volume Dice coefficient and mean Haussdorff distance were 0.61 ± 0.20 and 15.6 ± 7.4 mm respectively. The method has improvement potential which could be exploited in order for clinical introduction....

  3. Implications for Firms with Limited Information to Take Advantage of Reference Price Effect in Competitive Settings

    Directory of Open Access Journals (Sweden)

    Junhai Ma

    2017-01-01

    Full Text Available This paper studies internal reference price effects when competitive firms face reference price effects and make decisions based on partial information, where their decision-making mechanism is modeled by a dynamic adjustment process. It is shown that the evolution of this dynamic adjustment goes to stabilization if both adjustment speeds are small and the complexity of this evolution increases in adjustment speeds. It is proved that the necessary condition for flip bifurcation or Neimark-Sacker bifurcation will occur with the increase of adjustment speed in two special cases. What is more, numerical simulations show that these bifurcations do occur. Then, the impacts of parameters on stability and profits are investigated and some management insights for firms with limited information to take advantage of reference price effects are provided.

  4. Reference levels at diagnosis (NRD) for explorations in TC of the university Hospital Donostia

    International Nuclear Information System (INIS)

    Iriondo Igerabide, U.; Puertolas Hernandez, J. R.; Masso Odriozola, A.; Alonso Espinaco, M. t.; Pino Leon, C.; Lozano Flores, F. J.; Larretxea Etxarri, R.

    2013-01-01

    The objective of this work is the establishment of diagnostic reference levels in TC, for the anatomical regions, in the University Hospital Donostia, in order to reduce the dose to patients and without prejudice to the required diagnosis. (Author)

  5. Demons versus level-set motion registration for coronary 18F-sodium fluoride PET

    Science.gov (United States)

    Rubeaux, Mathieu; Joshi, Nikhil; Dweck, Marc R.; Fletcher, Alison; Motwani, Manish; Thomson, Louise E.; Germano, Guido; Dey, Damini; Berman, Daniel S.; Newby, David E.; Slomka, Piotr J.

    2016-03-01

    Ruptured coronary atherosclerotic plaques commonly cause acute myocardial infarction. It has been recently shown that active microcalcification in the coronary arteries, one of the features that characterizes vulnerable plaques at risk of rupture, can be imaged using cardiac gated 18F-sodium fluoride (18F-NaF) PET. We have shown in previous work that a motion correction technique applied to cardiac-gated 18F-NaF PET images can enhance image quality and improve uptake estimates. In this study, we further investigated the applicability of different algorithms for registration of the coronary artery PET images. In particular, we aimed to compare demons vs. level-set nonlinear registration techniques applied for the correction of cardiac motion in coronary 18F-NaF PET. To this end, fifteen patients underwent 18F-NaF PET and prospective coronary CT angiography (CCTA). PET data were reconstructed in 10 ECG gated bins; subsequently these gated bins were registered using demons and level-set methods guided by the extracted coronary arteries from CCTA, to eliminate the effect of cardiac motion on PET images. Noise levels, target-to-background ratios (TBR) and global motion were compared to assess image quality. Compared to the reference standard of using only diastolic PET image (25% of the counts from PET acquisition), cardiac motion registration using either level-set or demons techniques almost halved image noise due to the use of counts from the full PET acquisition and increased TBR difference between 18F-NaF positive and negative lesions. The demons method produces smoother deformation fields, exhibiting no singularities (which reflects how physically plausible the registration deformation is), as compared to the level-set method, which presents between 4 and 8% of singularities, depending on the coronary artery considered. In conclusion, the demons method produces smoother motion fields as compared to the level-set method, with a motion that is physiologically

  6. Evaluating the effects of alternative forest management plans under various physiographic settings using historical records as a reference

    Science.gov (United States)

    Yangjian Zhang; Hong S. He; Stephen R. Shifley; Jian Yang; Brian J. Palik

    2011-01-01

    Using historical General Land Office record as a reference, this study employed a landscape-scale disturbance and succession model to estimate the future cumulative effects of six alternative management plans on the tree species composition for various physiographic settings for the Mark Twain National Forest in Missouri. The results indicate that over a 200-year...

  7. Adaptable Value-Set Analysis for Low-Level Code

    OpenAIRE

    Brauer, Jörg; Hansen, René Rydhof; Kowalewski, Stefan; Larsen, Kim G.; Olesen, Mads Chr.

    2012-01-01

    This paper presents a framework for binary code analysis that uses only SAT-based algorithms. Within the framework, incremental SAT solving is used to perform a form of weakly relational value-set analysis in a novel way, connecting the expressiveness of the value sets to computational complexity. Another key feature of our framework is that it translates the semantics of binary code into an intermediate representation. This allows for a straightforward translation of the program semantics in...

  8. Impact of the choice of the precipitation reference data set on climate model selection and the resulting climate change signal

    Science.gov (United States)

    Gampe, D.; Ludwig, R.

    2017-12-01

    Regional Climate Models (RCMs) that downscale General Circulation Models (GCMs) are the primary tool to project future climate and serve as input to many impact models to assess the related changes and impacts under such climate conditions. Such RCMs are made available through the Coordinated Regional climate Downscaling Experiment (CORDEX). The ensemble of models provides a range of possible future climate changes around the ensemble mean climate change signal. The model outputs however are prone to biases compared to regional observations. A bias correction of these deviations is a crucial step in the impact modelling chain to allow the reproduction of historic conditions of i.e. river discharge. However, the detection and quantification of model biases are highly dependent on the selected regional reference data set. Additionally, in practice due to computational constraints it is usually not feasible to consider the entire ensembles of climate simulations with all members as input for impact models which provide information to support decision-making. Although more and more studies focus on model selection based on the preservation of the climate model spread, a selection based on validity, i.e. the representation of the historic conditions is still a widely applied approach. In this study, several available reference data sets for precipitation are selected to detect the model bias for the reference period 1989 - 2008 over the alpine catchment of the Adige River located in Northern Italy. The reference data sets originate from various sources, such as station data or reanalysis. These data sets are remapped to the common RCM grid at 0.11° resolution and several indicators, such as dry and wet spells, extreme precipitation and general climatology, are calculate to evaluate the capability of the RCMs to produce the historical conditions. The resulting RCM spread is compared against the spread of the reference data set to determine the related uncertainties and

  9. Use of the mini C-arm for wrist fractures - Establishing a diagnostic reference level

    International Nuclear Information System (INIS)

    Love, G. J.; Pillai, A.; Gibson, S.

    2008-01-01

    The establishment of diagnostic reference levels (DRLs) for all typical radiological examinations became mandatory following the implementation of the Ionising Radiations (Medical Exposure) Regulations Act 2000. At present, there are no national dosage guidelines in the UK regarding use of fluoroscopy in orthopaedic trauma. The increasing popularity of the mini C-arm image intensifier amongst surgeons has led to concerns regarding use of ionizing radiation by personnel who have not been trained in radiation protection. It is therefore essential to have formal protocols for use of the mini C-arm to comply with the law and to maintain safe clinical practice. It is attempted to provide dose data for wrist fracture manipulations that may be used as a basis for setting a DRL for this procedure. Screening times were recorded for 80 wrist manipulations in a fracture clinic setting using a mini C-arm image intensifier. A DRL was set using the third quartile value for screening time. The median screening time for wrist fractures was 20 s with a range from 1 to 177 s. The third quartile value for screening time was 34 s. This value can be used as a provisional DRL for wrist fracture manipulations. The DRL is a quantitative guide for the optimisation of radiological protection. IR(ME)R 2000 states that if it is consistently exceeded by an individual operator or a piece of equipment, investigation and remedial action must be taken. We recommend that trauma units establish their own local DRLs for common procedures as made mandatory by legislation. (authors)

  10. Diagnostic Reference Levels in the 1990 and 1996 Recommendations of the ICRP (invited paper)

    International Nuclear Information System (INIS)

    Drexler, G.

    1998-01-01

    A review of and some comments on the paragraphs in the ICRP Publications 60 and 73 are presented, which are relevant to diagnostic reference doses. The content of the statements is traced back by approximately 50 years when ICRP's preoccupation with the future health and well-being of the population is reflected in guidance for characterisation of 'normal operational conditions'. The early ICRP levels of reference doses are compared with the values currently discussed to demonstrate the importance of diagnostic reference doses in the process of optimisation and to show the importance of a continuous review and update of these levels. (author)

  11. Goal oriented Mathematics Survey at Preparatory Level- Revised set ...

    African Journals Online (AJOL)

    This cross sectional study design on mathematical syllabi at preparatory levels of the high schools was to investigate the efficiency of the subject at preparatory level education serving as a basis for several streams, like Natural science, Technology, Computer Science, Health Science and Agriculture found at tertiary levels.

  12. Use of INAA in the preparation of a set soil Reference Materials with certified values of total element contents

    International Nuclear Information System (INIS)

    Kucera, J.; Horakova, J.; Soukal, L.

    1997-01-01

    A set of certified Reference Materials was prepared consisting of four natural agricultural soils with normal (n) and elevated (e) levels of element contents: CRM 7001 Light Sandy Soil (n), CRM 7002 Light Sandy Soil (e), CRM 7003 Silty Clay Loam (n), and CRM 7004 Loam (e). In these materials, certified and/or information values of the total contents of the elements As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V and Zn, and their fractions extractable by aqua regia, boiling and cold 2M nitric acid were derived from an interlaboratory comparison in which 28 laboratories participated. Highly precise and accurate procedures of instrumental neutron activation analysis (INAA) were employed for homogeneity testing and also for certification of the total element contents. For comparation purposes, NIST SRM-2704 Buffalo River Sediment was analyzed by INAA, as well. The INAA results obtained compared very well with the certified and/or information values for four soil CRMs and also with NIST values for SRM-2704. From this agreement, a very high reliability of the new soil CRMs can be inferred. (author)

  13. BRSCW Reference Set Application: Karen Abbott -University of Arkansas (2014) — EDRN Public Portal

    Science.gov (United States)

    Our earlier glycoproteomic studies have identified bisecting glycoslyation and core fucosylation changes on particular glycoproteins in endometrioid ovarian cancer tissues and plasma (Abbott et al, 2010, Proteomics). We have validated that these glycan changes occur on the same glycoproteins in serous ovarian cancer plasma using a lectin-pull down western blot assays. We would like to used pooled reference samples to develop a sensitive magnetic bead-based assay to detect these glycoproteins with bisecting and core fucosylation changes.

  14. Genetic structure, diversity, and allelic richness in composite collection and reference set in chickpea (Cicer arietinum L.

    Directory of Open Access Journals (Sweden)

    Gowda Cholenahalli LL

    2008-10-01

    Full Text Available Abstract Background Plant genetic resources (PGR are the basic raw materials for future genetic progress and an insurance against unforeseen threats to agricultural production. An extensive characterization of PGR provides an opportunity to dissect structure, mine allelic variations, and identify diverse accessions for crop improvement. The Generation Challenge Program http://www.generationcp.org conceptualized the development of "composite collections" and extraction of "reference sets" from these for more efficient tapping of global crop-related genetic resources. In this study, we report the genetic structure, diversity and allelic richness in a composite collection of chickpea using SSR markers, and formation of a reference set of 300 accessions. Results The 48 SSR markers detected 1683 alleles in 2915 accessions, of which, 935 were considered rare, 720 common and 28 most frequent. The alleles per locus ranged from 14 to 67, averaged 35, and the polymorphic information content was from 0.467 to 0.974, averaged 0.854. Marker polymorphism varied between groups of accessions in the composite collection and reference set. A number of group-specific alleles were detected: 104 in Kabuli, 297 in desi, and 69 in wild Cicer; 114 each in Mediterranean and West Asia (WA, 117 in South and South East Asia (SSEA, and 10 in African region accessions. Desi and kabuli shared 436 alleles, while wild Cicer shared 17 and 16 alleles with desi and kabuli, respectively. The accessions from SSEA and WA shared 74 alleles, while those from Mediterranean 38 and 33 alleles with WA and SSEA, respectively. Desi chickpea contained a higher proportion of rare alleles (53% than kabuli (46%, while wild Cicer accessions were devoid of rare alleles. A genotype-based reference set captured 1315 (78% of the 1683 composite collection alleles of which 463 were rare, 826 common, and 26 the most frequent alleles. The neighbour-joining tree diagram of this reference set represents

  15. A Terrestrial Reference Frame realised on the observation level using a GPS-LEO satellite constellation

    Science.gov (United States)

    Koenig, Daniel

    2018-02-01

    Applying a one-step integrated process, i.e. by simultaneously processing all data and determining all satellite orbits involved, a Terrestrial Reference Frame (TRF) consisting of a geometric as well as a dynamic part has been determined at the observation level using the EPOS-OC software of Deutsches GeoForschungsZentrum. The satellite systems involved comprise the Global Positioning System (GPS) as well as the twin GRACE spacecrafts. Applying a novel approach, the inherent datum defect has been overcome empirically. In order not to rely on theoretical assumptions this is done by carrying out the TRF estimation based on simulated observations and using the associated satellite orbits as background truth. The datum defect is identified here as the total of all three translations as well as the rotation about the z-axis of the ground station network leading to a rank-deficient estimation problem. To rectify this singularity, datum constraints comprising no-net translation (NNT) conditions in x, y, and z as well as a no-net rotation (NNR) condition about the z-axis are imposed. Thus minimally constrained, the TRF solution covers a time span of roughly a year with daily resolution. For the geometric part the focus is put on Helmert transformations between the a priori and the estimated sets of ground station positions, and the dynamic part is represented by gravity field coefficients of degree one and two. The results of a reference solution reveal the TRF parameters to be estimated reliably with high precision. Moreover, carrying out a comparable two-step approach using the same data and models leads to parameters and observational residuals of worse quality. A validation w.r.t. external sources shows the dynamic origin to coincide at a level of 5 mm or better in x and y, and mostly better than 15 mm in z. Comparing the derived GPS orbits to IGS final orbits as well as analysing the SLR residuals for the GRACE satellites reveals an orbit quality on the few cm level

  16. Establishment of diagnostic reference levels for dental panoramic radiography in Greece

    International Nuclear Information System (INIS)

    Manousaridis, G.; Koukorava, C.; Hourdakis, C.J.; Kamenopoulou, V.; Yakoumakis, E.; Tsiklakis, K.

    2015-01-01

    The purpose of the present study was to present the national diagnostic reference levels (DRL) established for panoramic dental examinations in Greece. The establishment of DRL, as a tool for the optimisation of radiological procedures, is a requirement of national regulations. Measurements performed by the Greek Atomic Energy Commission on 90 panoramic systems have been used for the derivation of DRL values. DRL values have been proposed for exposure settings of different patient types (child, small adult and standard adult), both for film and digital imaging. The DRLs for different patient types are grouped in three categories: children, small adults (corresponding to female) and average adults (corresponding to male). Proposed DRLs for these groups are 2.2, 3.3 and 4.1 mGy, respectively. In order to investigate the correlation of DRLs with the available imaging modalities (CR, DR and film), this parameter was taken into account. DR imaging DRL is the lowest at 3.5 mGy, CR imaging the highest at 4.2 mGy and film imaging at 3.7 mGy. In order to facilitate comparison with other studies, kerma-width product values were calculated from K i , air and field size. (authors)

  17. Diagnostic reference levels and complexity indices in interventional radiology: a national programme

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Cruces, R.; Perez-Martinez, M.; Pastor-Vega, J.M.; Canete, S. [University of Malaga, School of Medicine, Malaga (Spain); Vano, E.; Fernandez-Soto, J.M.; Sanchez-Casanueva, R.; Gallego-Beuter, J.J. [Complutense University, San Carlos Hospital, Medical School, Madrid (Spain); Carrera-Magarino, F.; Moreno-Rodriguez, F.; Moreno-Sanchez, T. [Juan Ramon Jimenez University Hospital, Huelva (Spain); Soler-Cantos, M.M.; Canis-Lopez, M. [Reina Sofia University Hospital, Cordoba (Spain); Hernandez-Armas, J.; Diaz-Romero, F.J. [University Hospital of Canary Islands, Tenerife (Spain); Rosales-Espizua, F.; Lopez-Medina, A.; Gonzalez-de-Garay, M. [Basurto Hospital, Bilbao (Spain); Martin-Palanca, A. [Virgen de la Victoria University Hospital, Malaga (Spain); Gil-Agudo, A.; Zarca-Diaz, M.A.; Zapata-Jimenez, J.C. [General University Hospital, Ciudad Real (Spain); Parra-Osorio, V.; Munoz Ruiz-Canela, J.J.; Moreno-Saiz, C.; Galan-Montenegro, P. [Carlos Haya University Hospital, Malaga (Spain)

    2016-12-15

    To propose national diagnostic reference levels (DRLs) for interventional radiology and to evaluate the impact of the procedural complexity on patient doses. Eight interventional radiology units from Spanish hospitals were involved in this project. The participants agreed to undergo common quality control procedures for X-ray systems. Kerma area product (KAP) was collected from a sample of 1,649 procedures. A consensus document established the criteria to evaluate the complexity of seven types of procedures. DRLs were set as the 3rd quartile of KAP values. The KAP (3rd quartile) in Gy cm{sup 2} for the procedures included in the survey were: lower extremity arteriography (n = 784) 78; renal arteriography (n = 37) 107; transjugular hepatic biopsies (THB) (n = 30) 45; biliary drainage (BD) (n = 314) 30; uterine fibroid embolization (UFE) (n = 56) 214; colon endoprostheses (CE) (n = 31) 169; hepatic chemoembolization (HC) (n = 269) 303; femoropopliteal revascularization (FR) (n = 62) 119; and iliac stent (n = 66) 170. The complexity involved the increases in the following KAP factors from simple to complex procedures: THB x4; BD x13; UFE x3; CE x3; HC x5; FR x5 and IS x4. The evaluation of the procedure complexity in patient doses will allow the proper use of DRLs for the optimization of interventional radiology. (orig.)

  18. Structural lesions detected by magnetic resonance imaging in the spine of patients with spondyloarthritis - definitions, assessment system, and reference image set

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Maksymowych, Walter P; Pedersen, Susanne J

    2009-01-01

    are assessed at each vertebral endplate at all 23 spinal levels from C2/3 to L5/S1, whereas facet joint lesions are to be assessed by segmental level (cervical, thoracic, and lumbar). CONCLUSION: An anatomy-based set of definitions and an assessment system for structural lesions in the spine of patients......OBJECTIVE: There is no reliable and sensitive magnetic resonance imaging (MRI) assessment system for structural lesions in patients with spondyloarthritis (SpA). We sought to develop and illustrate a detailed anatomy-based set of MRI definitions and an assessment system for structural lesions...... in the spine of patients with SpA. METHODS: MRI definitions of different structural ("chronic") lesions at various anatomical locations in the spine, and an accompanying assessment system, were agreed by consensus within the Canada-Denmark MRI working group. Subsequently, a reference image set...

  19. Low-level lasers alter mRNA levels from traditional reference genes used in breast cancer cells

    Science.gov (United States)

    Teixeira, A. F.; Canuto, K. S.; Rodrigues, J. A.; Fonseca, A. S.; Mencalha, A. L.

    2017-07-01

    Cancer is among the leading causes of mortality worldwide, increasing the importance of treatment development. Low-level lasers are used in several diseases, but some concerns remains on cancers. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is a technique used to understand cellular behavior through quantification of mRNA levels. Output data from target genes are commonly relative to a reference that cannot vary according to treatment. This study evaluated reference genes levels from MDA-MB-231 cells exposed to red or infrared lasers at different fluences. Cultures were exposed to red and infrared lasers, incubated (4 h, 37 °C), total RNA was extracted and cDNA synthesis was performed to evaluate mRNA levels from ACTB, GUSB and TRFC genes by RT-qPCR. Specific amplification was verified by melting curves and agarose gel electrophoresis. RefFinder enabled data analysis by geNorm, NormFinder and BestKeeper. Specific amplifications were obtained and, although mRNA levels from ACTB, GUSB or TRFC genes presented no significant variation through traditional statistical analysis, Excel-based tools revealed that the use of these reference genes are dependent of laser characteristics. Our data showed that exposure to low-level red and infrared lasers at different fluences alter the mRNA levels from ACTB, GUSB and TRFC in MDA-MB-231 cells.

  20. Definitive Characterization of CA 19-9 in Resectable Pancreatic Cancer Using a Reference Set of Serum and Plasma Specimens.

    Science.gov (United States)

    Haab, Brian B; Huang, Ying; Balasenthil, Seetharaman; Partyka, Katie; Tang, Huiyuan; Anderson, Michelle; Allen, Peter; Sasson, Aaron; Zeh, Herbert; Kaul, Karen; Kletter, Doron; Ge, Shaokui; Bern, Marshall; Kwon, Richard; Blasutig, Ivan; Srivastava, Sudhir; Frazier, Marsha L; Sen, Subrata; Hollingsworth, Michael A; Rinaudo, Jo Ann; Killary, Ann M; Brand, Randall E

    2015-01-01

    The validation of candidate biomarkers often is hampered by the lack of a reliable means of assessing and comparing performance. We present here a reference set of serum and plasma samples to facilitate the validation of biomarkers for resectable pancreatic cancer. The reference set includes a large cohort of stage I-II pancreatic cancer patients, recruited from 5 different institutions, and relevant control groups. We characterized the performance of the current best serological biomarker for pancreatic cancer, CA 19-9, using plasma samples from the reference set to provide a benchmark for future biomarker studies and to further our knowledge of CA 19-9 in early-stage pancreatic cancer and the control groups. CA 19-9 distinguished pancreatic cancers from the healthy and chronic pancreatitis groups with an average sensitivity and specificity of 70-74%, similar to previous studies using all stages of pancreatic cancer. Chronic pancreatitis patients did not show CA 19-9 elevations, but patients with benign biliary obstruction had elevations nearly as high as the cancer patients. We gained additional information about the biomarker by comparing two distinct assays. The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis. Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.

  1. Definitive Characterization of CA 19-9 in Resectable Pancreatic Cancer Using a Reference Set of Serum and Plasma Specimens.

    Directory of Open Access Journals (Sweden)

    Brian B Haab

    Full Text Available The validation of candidate biomarkers often is hampered by the lack of a reliable means of assessing and comparing performance. We present here a reference set of serum and plasma samples to facilitate the validation of biomarkers for resectable pancreatic cancer. The reference set includes a large cohort of stage I-II pancreatic cancer patients, recruited from 5 different institutions, and relevant control groups. We characterized the performance of the current best serological biomarker for pancreatic cancer, CA 19-9, using plasma samples from the reference set to provide a benchmark for future biomarker studies and to further our knowledge of CA 19-9 in early-stage pancreatic cancer and the control groups. CA 19-9 distinguished pancreatic cancers from the healthy and chronic pancreatitis groups with an average sensitivity and specificity of 70-74%, similar to previous studies using all stages of pancreatic cancer. Chronic pancreatitis patients did not show CA 19-9 elevations, but patients with benign biliary obstruction had elevations nearly as high as the cancer patients. We gained additional information about the biomarker by comparing two distinct assays. The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis. Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.

  2. Transcriptome-wide selection of a reliable set of reference genes for gene expression studies in potato cyst nematodes (Globodera spp.).

    Science.gov (United States)

    Sabeh, Michael; Duceppe, Marc-Olivier; St-Arnaud, Marc; Mimee, Benjamin

    2018-01-01

    Relative gene expression analyses by qRT-PCR (quantitative reverse transcription PCR) require an internal control to normalize the expression data of genes of interest and eliminate the unwanted variation introduced by sample preparation. A perfect reference gene should have a constant expression level under all the experimental conditions. However, the same few housekeeping genes selected from the literature or successfully used in previous unrelated experiments are often routinely used in new conditions without proper validation of their stability across treatments. The advent of RNA-Seq and the availability of public datasets for numerous organisms are opening the way to finding better reference genes for expression studies. Globodera rostochiensis is a plant-parasitic nematode that is particularly yield-limiting for potato. The aim of our study was to identify a reliable set of reference genes to study G. rostochiensis gene expression. Gene expression levels from an RNA-Seq database were used to identify putative reference genes and were validated with qRT-PCR analysis. Three genes, GR, PMP-3, and aaRS, were found to be very stable within the experimental conditions of this study and are proposed as reference genes for future work.

  3. Relationships between college settings and student alcohol use before, during and after events: a multi-level study.

    Science.gov (United States)

    Paschall, Mallie J; Saltz, Robert F

    2007-11-01

    We examined how alcohol risk is distributed based on college students' drinking before, during and after they go to certain settings. Students attending 14 California public universities (N=10,152) completed a web-based or mailed survey in the fall 2003 semester, which included questions about how many drinks they consumed before, during and after the last time they went to six settings/events: fraternity or sorority party, residence hall party, campus event (e.g. football game), off-campus party, bar/restaurant and outdoor setting (referent). Multi-level analyses were conducted in hierarchical linear modeling (HLM) to examine relationships between type of setting and level of alcohol use before, during and after going to the setting, and possible age and gender differences in these relationships. Drinking episodes (N=24,207) were level 1 units, students were level 2 units and colleges were level 3 units. The highest drinking levels were observed during all settings/events except campus events, with the highest number of drinks being consumed at off-campus parties, followed by residence hall and fraternity/sorority parties. The number of drinks consumed before a fraternity/sorority party was higher than other settings/events. Age group and gender differences in relationships between type of setting/event and 'before,''during' and 'after' drinking levels also were observed. For example, going to a bar/restaurant (relative to an outdoor setting) was positively associated with 'during' drinks among students of legal drinking age while no relationship was observed for underage students. Findings of this study indicate differences in the extent to which college settings are associated with student drinking levels before, during and after related events, and may have implications for intervention strategies targeting different types of settings.

  4. A high confidence, manually validated human blood plasma protein reference set

    DEFF Research Database (Denmark)

    Schenk, Susann; Schoenhals, Gary J; de Souza, Gustavo

    2008-01-01

    BACKGROUND: The immense diagnostic potential of human plasma has prompted great interest and effort in cataloging its contents, exemplified by the Human Proteome Organization (HUPO) Plasma Proteome Project (PPP) pilot project. Due to challenges in obtaining a reliable blood plasma protein list......-trap-Fourier transform (LTQ-FT) and a linear ion trap-Orbitrap (LTQ-Orbitrap) for mass spectrometry (MS) analysis. Both instruments allow the measurement of peptide masses in the low ppm range. Furthermore, we employed a statistical score that allows database peptide identification searching using the products of two...... consecutive stages of tandem mass spectrometry (MS3). The combination of MS3 with very high mass accuracy in the parent peptide allows peptide identification with orders of magnitude more confidence than that typically achieved. RESULTS: Herein we established a high confidence set of 697 blood plasma proteins...

  5. Trusting Politicians and Institutions in a Multi-Level Setting

    DEFF Research Database (Denmark)

    Hansen, Sune Welling; Kjær, Ulrik

    Trust in government and in politicians is a very crucial prerequisite for democratic processes. This goes not only for the national level of government but also for the regional and local. We make use of a large scale survey among citizens in Denmark to evaluate trust in politicians at different...... formation processes can negatively influence trust in the mayor and the councilors. Reaching out for the local power by being disloyal to one’s own party or by breaking deals already made can sometimes secure the mayoralty but it comes with a prize: lower trust among the electorate....

  6. Comparing climate and cost impacts of reference levels for reducing emissions from deforestation

    Energy Technology Data Exchange (ETDEWEB)

    Busch, Jonah [Center for Applied Biodiversity Science, Conservation International, 2011 Crystal Drive, Suite 500, Arlington, VA (United States); Strassburg, Bernardo [Center for Social and Economic Research on the Global Environment, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Cattaneo, Andrea [Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540-1644 (United States); Lubowski, Ruben [Environmental Defense Fund, 1875 Connecticut Avenue NW, Washington, DC (United States); Bruner, Aaron; Rice, Richard; Boltz, Frederick [Conservation International, 2011 Crystal Drive, Suite 500, Arlington, VA (United States); Creed, Anna; Ashton, Ralph, E-mail: jbusch@conservation.or [Terrestrial Carbon Group, 900 17th Street NW, Suite 700, Washington, DC (United States)

    2009-10-15

    The climate benefit and economic cost of an international mechanism for reducing emissions from deforestation and degradation (REDD) will depend on the design of reference levels for crediting emission reductions. We compare the impacts of six proposed reference level designs on emission reduction levels and on cost per emission reduction using a stylized partial equilibrium model (the open source impacts of REDD incentives spreadsheet; OSIRIS). The model explicitly incorporates national incentives to participate in an international REDD mechanism as well as international leakage of deforestation emissions. Our results show that a REDD mechanism can provide cost-efficient climate change mitigation benefits under a broad range of reference level designs. We find that the most effective reference level designs balance incentives to reduce historically high deforestation emissions with incentives to maintain historically low deforestation emissions. Estimates of emission reductions under REDD depend critically on the degree to which demand for tropical frontier agriculture generates leakage. This underscores the potential importance to REDD of complementary strategies to supply agricultural needs outside of the forest frontier.

  7. Comparing climate and cost impacts of reference levels for reducing emissions from deforestation

    International Nuclear Information System (INIS)

    Busch, Jonah; Strassburg, Bernardo; Cattaneo, Andrea; Lubowski, Ruben; Bruner, Aaron; Rice, Richard; Boltz, Frederick; Creed, Anna; Ashton, Ralph

    2009-01-01

    The climate benefit and economic cost of an international mechanism for reducing emissions from deforestation and degradation (REDD) will depend on the design of reference levels for crediting emission reductions. We compare the impacts of six proposed reference level designs on emission reduction levels and on cost per emission reduction using a stylized partial equilibrium model (the open source impacts of REDD incentives spreadsheet; OSIRIS). The model explicitly incorporates national incentives to participate in an international REDD mechanism as well as international leakage of deforestation emissions. Our results show that a REDD mechanism can provide cost-efficient climate change mitigation benefits under a broad range of reference level designs. We find that the most effective reference level designs balance incentives to reduce historically high deforestation emissions with incentives to maintain historically low deforestation emissions. Estimates of emission reductions under REDD depend critically on the degree to which demand for tropical frontier agriculture generates leakage. This underscores the potential importance to REDD of complementary strategies to supply agricultural needs outside of the forest frontier.

  8. Referent 3D tumor model at cellular level in radionuclide therapy

    International Nuclear Information System (INIS)

    Spaic, R.; Ilic, R.D.; Petrovic, B.J.

    2002-01-01

    Aim Conventional internal dosimetry has a lot of limitations because of tumor dose nonuniformity. The best approach for absorbed dose at cellular level for different tumors in radionuclide therapy calculation is Monte Carlo method. The purpose of this study is to introduce referent tumor 3D model at cellular level for Monte Carlo simulation study in radionuclide therapy. Material and Methods The moment when tumor is detectable and when same therapy can start is time period in which referent 3D tumor model at cellular level was defined. In accordance with tumor growth rate at that moment he was a sphere with same radius (10 000 μm). In that tumor there are cells or cluster of cells, which are randomly distributed spheres. Distribution of cells/cluster of cells can be calculated from histology data but it was assumed that this distribution is normal with the same mean value and standard deviation (100±50 mm). Second parameter, which was selected to define referent tumor, is volume density of cells (30%). In this referent tumor there are no necroses. Stroma is defined as space between spheres with same concentration of materials as in spheres. Results: Referent tumor defined on this way have about 2,2 10 5 cells or cluster of cells random distributed. Using this referent 3D tumor model and for same concentration of radionuclides (1:100) and energy of beta emitters (1000 keV) which are homogeneously distributed in labeled cells absorbed dose for all cells was calculated. Simulations are done using FOTELP Monte Carlo code, which is modified for this purposes. Results of absorbed dose in cells are given in numerical values (1D distribution) and as the images (2D or 3D distributions). Conclusion Geometrical module for Monte Carlo simulation study can be standardized by introducing referent 3D tumor model at cellular level. This referent 3D tumor model gives most realistic presentation of different tumors at the moment of their detectability. Referent 3D tumor model at

  9. High-level waste tank farm set point document

    International Nuclear Information System (INIS)

    Anthony, J.A. III.

    1995-01-01

    Setpoints for nuclear safety-related instrumentation are required for actions determined by the design authorization basis. Minimum requirements need to be established for assuring that setpoints are established and held within specified limits. This document establishes the controlling methodology for changing setpoints of all classifications. The instrumentation under consideration involve the transfer, storage, and volume reduction of radioactive liquid waste in the F- and H-Area High-Level Radioactive Waste Tank Farms. The setpoint document will encompass the PROCESS AREA listed in the Safety Analysis Report (SAR) (DPSTSA-200-10 Sup 18) which includes the diversion box HDB-8 facility. In addition to the PROCESS AREAS listed in the SAR, Building 299-H and the Effluent Transfer Facility (ETF) are also included in the scope

  10. High-level waste tank farm set point document

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, J.A. III

    1995-01-15

    Setpoints for nuclear safety-related instrumentation are required for actions determined by the design authorization basis. Minimum requirements need to be established for assuring that setpoints are established and held within specified limits. This document establishes the controlling methodology for changing setpoints of all classifications. The instrumentation under consideration involve the transfer, storage, and volume reduction of radioactive liquid waste in the F- and H-Area High-Level Radioactive Waste Tank Farms. The setpoint document will encompass the PROCESS AREA listed in the Safety Analysis Report (SAR) (DPSTSA-200-10 Sup 18) which includes the diversion box HDB-8 facility. In addition to the PROCESS AREAS listed in the SAR, Building 299-H and the Effluent Transfer Facility (ETF) are also included in the scope.

  11. Multi-phase flow monitoring with electrical impedance tomography using level set based method

    International Nuclear Information System (INIS)

    Liu, Dong; Khambampati, Anil Kumar; Kim, Sin; Kim, Kyung Youn

    2015-01-01

    Highlights: • LSM has been used for shape reconstruction to monitor multi-phase flow using EIT. • Multi-phase level set model for conductivity is represented by two level set functions. • LSM handles topological merging and breaking naturally during evolution process. • To reduce the computational time, a narrowband technique was applied. • Use of narrowband and optimization approach results in efficient and fast method. - Abstract: In this paper, a level set-based reconstruction scheme is applied to multi-phase flow monitoring using electrical impedance tomography (EIT). The proposed scheme involves applying a narrowband level set method to solve the inverse problem of finding the interface between the regions having different conductivity values. The multi-phase level set model for the conductivity distribution inside the domain is represented by two level set functions. The key principle of the level set-based method is to implicitly represent the shape of interface as the zero level set of higher dimensional function and then solve a set of partial differential equations. The level set-based scheme handles topological merging and breaking naturally during the evolution process. It also offers several advantages compared to traditional pixel-based approach. Level set-based method for multi-phase flow is tested with numerical and experimental data. It is found that level set-based method has better reconstruction performance when compared to pixel-based method

  12. Can traditional birth attendants be trained to accurately identify septic infants, initiate antibiotics, and refer in a rural African setting?

    Science.gov (United States)

    Gill, Christopher John; MacLeod, William B; Phiri-Mazala, Grace; Guerina, Nicholas G; Mirochnick, Mark; Knapp, Anna B; Hamer, Davidson H

    2014-08-01

    Neonatal sepsis is a major cause of neonatal mortality. In populations with limited access to health care, early identification of bacterial infections and initiation of antibiotics by community health workers (CHWs) could be lifesaving. It is unknown whether this strategy would be feasible using traditional birth attendants (TBAs), a cadre of CHWs who typically have limited training and educational backgrounds. We analyzed data from the intervention arm of a cluster-randomized trial involving TBAs in Lufwanyama District, Zambia, from June 2006 to November 2008. TBAs followed neonates for signs of potential infection through 28 days of life. If any of 16 criteria were met, TBAs administered oral amoxicillin and facilitated referral to a rural health center. Our analysis included 1,889 neonates with final vital status by day 28. TBAs conducted a median of 2 (interquartile range 2-6) home visits (51.4% in week 1 and 48.2% in weeks 2-4) and referred 208 neonates (11%) for suspected sepsis. Of referred neonates, 176/208 (84.6%) completed their referral. Among neonates given amoxicillin, 171/183 (93.4%) were referred; among referred neonates, 171/208 (82.2%) received amoxicillin. Referral and/or initiation of antibiotics were strongly associated with neonatal death (for referral, relative risk [RR] = 7.93, 95% confidence interval [CI] = 4.4-14.3; for amoxicillin administration, RR = 4.7, 95% CI = 2.4-8.7). Neonates clinically judged to be "extremely sick" by the referring TBA were at greatest risk of death (RR = 8.61, 95% CI = 4.0-18.5). The strategy of administering a first dose of antibiotics and referring based solely on the clinical evaluation of a TBA is feasible and could be effective in reducing neonatal mortality in remote rural settings.

  13. Mind-sets, low-level exposures, and research

    International Nuclear Information System (INIS)

    Sagan, L.A.

    1993-01-01

    Much of our environmental policy is based on the notion that carcinogenic agents are harmful at even minuscule doses. From where does this thinking come? What is the scientific evidence that supports such policy? Moreover, why is the public willing to buy into this? Or is it the other way around: Has the scientific community bought into a paradigm that has its origins in public imagery? Or, most likely, are there interactions between the two? It is essential that we find out whether or not there are risks associated with low-level exposures to radiation. The author can see three obvious areas where the future depends on better information: The increasing radiation exposures resulting from the use of medical diagnostic and therapeutic practices need to be properly evaluated for safety; Environmental policies, which direct enormous resources to the reduction of small radiation exposures, needs to be put on a firmer scientific basis; The future of nuclear energy, dependent as it is on public acceptance, may well rely upon a better understanding of low-dose effects. Nuclear energy could provide an important solution of global warming and other possible environmental hazards, but will probably not be implemented as long as fear of low-dose radiation persists. Although an established paradigm has great resilience, it cannot resist the onslaught of inconsistent scientific observations or of the social value system that supports it. Only new research will enable us to determine if a paradigm shift is in order here

  14. A set-theoretic model reference adaptive control architecture for disturbance rejection and uncertainty suppression with strict performance guarantees

    Science.gov (United States)

    Arabi, Ehsan; Gruenwald, Benjamin C.; Yucelen, Tansel; Nguyen, Nhan T.

    2018-05-01

    Research in adaptive control algorithms for safety-critical applications is primarily motivated by the fact that these algorithms have the capability to suppress the effects of adverse conditions resulting from exogenous disturbances, imperfect dynamical system modelling, degraded modes of operation, and changes in system dynamics. Although government and industry agree on the potential of these algorithms in providing safety and reducing vehicle development costs, a major issue is the inability to achieve a-priori, user-defined performance guarantees with adaptive control algorithms. In this paper, a new model reference adaptive control architecture for uncertain dynamical systems is presented to address disturbance rejection and uncertainty suppression. The proposed framework is predicated on a set-theoretic adaptive controller construction using generalised restricted potential functions.The key feature of this framework allows the system error bound between the state of an uncertain dynamical system and the state of a reference model, which captures a desired closed-loop system performance, to be less than a-priori, user-defined worst-case performance bound, and hence, it has the capability to enforce strict performance guarantees. Examples are provided to demonstrate the efficacy of the proposed set-theoretic model reference adaptive control architecture.

  15. An approach and a tool for setting sustainable energy retrofitting strategies referring to the 2010 EP

    Directory of Open Access Journals (Sweden)

    Charlot-Valdieu, C.

    2011-10-01

    Full Text Available The 2010 EPBD asks for an economic and social analysis in order to preserve social equity and to promote innovation and building productivity. This is possible with a life cycle energy cost (LCEC analysis, such as with the SEC (Sustainable Energy Cost model whose bottom up approach begins with a building typology including inhabitants. Then the analysis of some representative buildings includes the identification of a technico-economical optimum and energy retrofitting scenarios for each retrofitting programme and the extrapolation for the whole building stock. An extrapolation for the whole building stock allows to set up the strategy and to identify the needed means for reaching the objectives. SEC is a decision aid tool for optimising sustainable energy retrofitting strategies for buildings at territorial and patrimonial scales inside a sustainable development approach towards the factor 4. Various versions of the SEC model are now available for housing and for tertiary buildings.

    La directiva europea de 2010 sobre eficiencia energética en los edificios exige un análisis económico y social con el objetivo de preservar la equidad social, promover la innovación y reforzar la productividad en la construcción. Esto es posible con el análisis del coste global ampliado y especialmente con el modelo SEC. El análisis “bottom up” realizado con la SEC se basa en una tipología de edificio/usuario y en el análisis de edificios representativos: la identificación del óptimo técnico-económico y elaboración de escenarios antes de hacer una extrapolación al conjunto del parque. SEC es una herramienta de ayuda a la decisión para desarrollar estrategias territoriales o patrimoniales de rehabilitación energética. Existen diversas versiones del modelo: para edificios residenciales (unifamiliares y plurifamiliares, públicos y privados y para edificios terciarios.

  16. Low-level lead exposure effects on spatial reference memory and working memory in rats

    Institute of Scientific and Technical Information of China (English)

    Xinhua Yang; Ping Zhou; Yonghui Li

    2009-01-01

    BACKGROUND: Studies have demonstrated that lead exposure can result in cognitive dysfunction and behavior disorders. However, lead exposure impairments vary under different experimental conditions.OBJECTIVE: To detect changes in spatial learning and memory following low-level lead exposure in rats, in Morris water maze test under the same experimental condition used to analyze lead exposure effects on various memory types and learning processes.DESIGN AND SETTING: The experiment was conducted at the Animal Laboratory, Institute of Psychology, Chinese Academy of Science between February 2005 and March 2006. One-way analysis of variance (ANOVA) and behavioral observations were performed.MATERIALS: Sixteen male, healthy, adult, Sprague Dawley rats were randomized into normal control and lead exposure groups (n = 8).METHODS: Rats in the normal control group were fed distilled water, and those in the lead exposure group were fed 250 mL of 0.05% lead acetate once per day. At day 28, all rats performed the Morris water maze test, consisting of four phases: space navigation, probe test, working memory test, and visual cue test.MAIN OUTCOME MEASURES: Place navigation in the Morris water maze was used to evaluate spatial learning and memory, probe trials for spatial reference memory, working memory test for spatial working memory, and visual cue test for non-spatial cognitive function. Perkin-Elmer Model 300 Atomic Absorption Spectrometer was utilized to determine blood lead levels in rats.RESULTS: (1) In the working memory test, the time to reach the platform remained unchanged between the control and lead exposure groups (F(1,1) = 0.007, P = 0.935). A visible decrease in escape latencies was observed in each group (P = 0.028). However, there was no significant difference between the two groups (F(1,1) = 1.869, P = 0.193). The working memory probe test demonstrated no change between the two groups in the time spent in the target quadrant during the working memory probe test

  17. The impact of ICT in classic setting law. Special reference to the principle of territoriality

    Directory of Open Access Journals (Sweden)

    Víctor Almonacid Lamelas

    2016-05-01

    Full Text Available The multiplicity of legislative powers established by the end of the last century (with international and european law reached its highest level of complexity with the massification of the internet and the emergence of a new and necessary self-regulatory framework, probably something similar to a new «legislator» or «legislative power» consisting of the giants of the network. Does this mean that the existence of this new branch of law is, above all, the disappearance of physical space, colliding directly with the traditional principle of territoriality that characterized law as we have known it. Regarding the infinity of questions and issues, some legal and others which are very interesting indeed, have caused the arise of considerable concern. The main point is, first of all, to be aware of this new situation of «extraterritoriality», and thereafter meet the new legal or law effects of these new relationships. The debate on the need for international cyberlaw, or the immediate response to the new situations or amere confidence in this «self-regulated» system to some extent. It is an issue that can simply be raised and left open, although there is clearly a more judicious answer which can only a result of a clever combination of all solutions. In fact this area is not going to be covered in just one project, so we have focused on the relationships of private law –extracontractual and contractual–, and the impact of the problems related to intellectual property and criminal law. We try to prove that «ICT Law» is not a new area of law, but rather a new scenario where relations and legal effects are produced.

  18. Radon reference levels and priority areas considering optimisation and avertable lung cancers

    International Nuclear Information System (INIS)

    Bochicchio, F.; Venoso, G.; Antignani, S.; Carpentieri, C.

    2017-01-01

    Protection from radon exposure in workplaces and dwellings, as included in the latest relevant international regulations and recommendations, is based on the new concept of 'reference level' whose meaning is significantly different from that of previous 'action level' concept. In fact, whereas remedial actions had to be considered only for radon concentrations above the action level, actions to optimise radon exposure are requested with priority above reference level but optimisation should be applied also for radon concentrations below reference level. Similar considerations can be applied to the usually called 'Rn-prone' areas, which are here proposed to be regulated as 'priority' areas. The main implication of these new challenging concepts is a substantial increase of avertable lung cancer deaths, as it will be shown using Italian data. Some practical examples of possible policy actions fitting an approach based on these new concepts will also be given, which could be useful for the implementation of the Council Directive 2013/59/Euratom. (authors)

  19. Advice concerning the advantages of a reference incinerator for low-level and intermediate-level radioactive waste processing

    International Nuclear Information System (INIS)

    Luyten, G.B.

    1985-05-01

    In this report, an inventory is presented of new incinerators and flue gas filters used in low and intermediate-level radioactive waste combustion. It is argued that a 'reference equipment' for the combustion of solid and liquid low- and intermediate-level wastes best meets existing Dutch radiation protection standards. A cost-benefit analysis of such an equipment is given including annual costs of investment, capital and exploration. A separate combustion process of organic liquids and carrions is considered finally. (G.J.P.)

  20. The establishment of local diagnostic reference levels for paediatric interventional cardiology

    International Nuclear Information System (INIS)

    McFadden, S.; Hughes, C.; D'Helft, C.I.; McGee, A.; Rainford, L.; Brennan, P.C.; McCrum-Gardner, E.; Winder, R.J.

    2013-01-01

    Background: There is a paucity of information worldwide on radiation exposure in paediatric interventional cardiology. At present Nationally established Diagnostic Reference Levels exist for adult interventional cardiology procedures in the UK but little data is available for paediatrics. In addition, interventional cardiology has been identified as one the highest contributors to medical exposure to ionising radiation and children are more radiosensitive than adults. Objective: This study sought to determine current radiation dose levels in paediatric interventional cardiology (IC) with a view to establishing local diagnostic reference levels (LDRL). Methods: Radiation dose and examination details were recorded for 354 paediatric patients examined by IC in a specialised paediatric centre in Europe. Radiation doses were recorded using a Dose Area Product meter along with examination details. Procedures were categorised as either diagnostic (A) or therapeutic (B). Data was further sub-divided into five age ranges; (1) newborn <1 year (2) 1 <5 years (3) 5 <10 years (4) 10 <15 years (5) 15 years and over. Proposed LDRL were calculated from the mean dose area product readings. Results: The mean patient age was 2.6 years (range 0.0 days–16 years) and weight was 14.9 kg (range 2.4–112 kg). LDRL for the five age groupings were calculated as 190, 421, 582, 1289 and 1776 cGycm² respectively. Conclusion: Local dose reference levels have been proposed for paediatric IC and can be used as a benchmark for other hospitals to compare against their own radiation doses

  1. The Influence of the Terrestrial Reference Frame on Studies of Sea Level Change

    Science.gov (United States)

    Nerem, R. S.; Bar-Sever, Y. E.; Haines, B. J.; Desai, S.; Heflin, M. B.

    2015-12-01

    The terrestrial reference frame (TRF) provides the foundation for the accurate monitoring of sea level using both ground-based (tide gauges) and space-based (satellite altimetry) techniques. For the latter, tide gauges are also used to monitor drifts in the satellite instruments over time. The accuracy of the terrestrial reference frame (TRF) is thus a critical component for both types of sea level measurements. The TRF is central to the formation of geocentric sea-surface height (SSH) measurements from satellite altimeter data. The computed satellite orbits are linked to a particular TRF via the assumed locations of the ground-based tracking systems. The manner in which TRF errors are expressed in the orbit solution (and thus SSH) is not straightforward, and depends on the models of the forces underlying the satellite's motion. We discuss this relationship, and provide examples of the systematic TRF-induced errors in the altimeter derived sea-level record. The TRF is also crucial to the interpretation of tide-gauge measurements, as it enables the separation of vertical land motion from volumetric changes in the water level. TRF errors affect tide gauge measurements through GNSS estimates of the vertical land motion at each tide gauge. This talk will discuss the current accuracy of the TRF and how errors in the TRF impact both satellite altimeter and tide gauge sea level measurements. We will also discuss simulations of how the proposed Geodetic Reference Antenna in SPace (GRASP) satellite mission could reduce these errors and revolutionize how reference frames are computed in general.

  2. Joint level-set and spatio-temporal motion detection for cell segmentation.

    Science.gov (United States)

    Boukari, Fatima; Makrogiannis, Sokratis

    2016-08-10

    Cell segmentation is a critical step for quantification and monitoring of cell cycle progression, cell migration, and growth control to investigate cellular immune response, embryonic development, tumorigenesis, and drug effects on live cells in time-lapse microscopy images. In this study, we propose a joint spatio-temporal diffusion and region-based level-set optimization approach for moving cell segmentation. Moving regions are initially detected in each set of three consecutive sequence images by numerically solving a system of coupled spatio-temporal partial differential equations. In order to standardize intensities of each frame, we apply a histogram transformation approach to match the pixel intensities of each processed frame with an intensity distribution model learned from all frames of the sequence during the training stage. After the spatio-temporal diffusion stage is completed, we compute the edge map by nonparametric density estimation using Parzen kernels. This process is followed by watershed-based segmentation and moving cell detection. We use this result as an initial level-set function to evolve the cell boundaries, refine the delineation, and optimize the final segmentation result. We applied this method to several datasets of fluorescence microscopy images with varying levels of difficulty with respect to cell density, resolution, contrast, and signal-to-noise ratio. We compared the results with those produced by Chan and Vese segmentation, a temporally linked level-set technique, and nonlinear diffusion-based segmentation. We validated all segmentation techniques against reference masks provided by the international Cell Tracking Challenge consortium. The proposed approach delineated cells with an average Dice similarity coefficient of 89 % over a variety of simulated and real fluorescent image sequences. It yielded average improvements of 11 % in segmentation accuracy compared to both strictly spatial and temporally linked Chan

  3. Digital immunohistochemistry wizard: image analysis-assisted stereology tool to produce reference data set for calibration and quality control.

    Science.gov (United States)

    Plancoulaine, Benoît; Laurinaviciene, Aida; Meskauskas, Raimundas; Baltrusaityte, Indra; Besusparis, Justinas; Herlin, Paulette; Laurinavicius, Arvydas

    2014-01-01

    Digital image analysis (DIA) enables better reproducibility of immunohistochemistry (IHC) studies. Nevertheless, accuracy of the DIA methods needs to be ensured, demanding production of reference data sets. We have reported on methodology to calibrate DIA for Ki67 IHC in breast cancer tissue based on reference data obtained by stereology grid count. To produce the reference data more efficiently, we propose digital IHC wizard generating initial cell marks to be verified by experts. Digital images of proliferation marker Ki67 IHC from 158 patients (one tissue microarray spot per patient) with an invasive ductal carcinoma of the breast were used. Manual data (mD) were obtained by marking Ki67-positive and negative tumour cells, using a stereological method for 2D object enumeration. DIA was used as an initial step in stereology grid count to generate the digital data (dD) marks by Aperio Genie and Nuclear algorithms. The dD were collected into XML files from the DIA markup images and overlaid on the original spots along with the stereology grid. The expert correction of the dD marks resulted in corrected data (cD). The percentages of Ki67 positive tumour cells per spot in the mD, dD, and cD sets were compared by single linear regression analysis. Efficiency of cD production was estimated based on manual editing effort. The percentage of Ki67-positive tumor cells was in very good agreement in the mD, dD, and cD sets: regression of cD from dD (R2=0.92) reflects the impact of the expert editing the dD as well as accuracy of the DIA used; regression of the cD from the mD (R2=0.94) represents the consistency of the DIA-assisted ground truth (cD) with the manual procedure. Nevertheless, the accuracy of detection of individual tumour cells was much lower: in average, 18 and 219 marks per spot were edited due to the Genie and Nuclear algorithm errors, respectively. The DIA-assisted cD production in our experiment saved approximately 2/3 of manual marking. Digital IHC wizard

  4. Estimates of diagnostic reference levels for common radiographic x-ray examinations in some sudanese hospitals

    International Nuclear Information System (INIS)

    Awad, Ezdehar Mohammed Satti.

    2016-03-01

    The objective of this study were to estimate patient dose in some common diagnostic x-ray examinations in Sudan with the aim to propose national diagnostic reference levels (DRLs). Radiation doses were estimated for the patients in 23 public hospitals in different town in Sudan (Wad-Madani, Kasala, Atbara Al obaid, Al nhod, Khartoum). Entrance surface air kerma (ESAK) was estimated in a three steps protocol: First, x-ray unit output Y (d) was measured at a distance at a distance (d) for different peak tube voltages and tube loading (mAs). Next, incident air kerma (k) was calculated from Y (d) using inverse square law combined with patient exposure factors. ESAK was calculated from k using backscatter factor, B. Mean ESAK values were comparable to those reported in other countries and are below reference dose levels. The estimated mean ESAK values were: 0.4, 1.9, 1.8, 3.2, 2.4, 3.5, and 8.4 mGy for chests . The estimated mean ESAK values were 0.4, 1.9, 1.8, 3.2, 2.4, 3,5, and 8.4 mGy for chest PA, Skull AP/PA, Skull LAT, Abdomen Pelvis AP, Lumber Spine AP and Lumber Spine LAT examination respectively. The results are used for dose optimization and to propose national diagnostic reference levels. (Author)

  5. A local level set method based on a finite element method for unstructured meshes

    International Nuclear Information System (INIS)

    Ngo, Long Cu; Choi, Hyoung Gwon

    2016-01-01

    A local level set method for unstructured meshes has been implemented by using a finite element method. A least-square weighted residual method was employed for implicit discretization to solve the level set advection equation. By contrast, a direct re-initialization method, which is directly applicable to the local level set method for unstructured meshes, was adopted to re-correct the level set function to become a signed distance function after advection. The proposed algorithm was constructed such that the advection and direct reinitialization steps were conducted only for nodes inside the narrow band around the interface. Therefore, in the advection step, the Gauss–Seidel method was used to update the level set function using a node-by-node solution method. Some benchmark problems were solved by using the present local level set method. Numerical results have shown that the proposed algorithm is accurate and efficient in terms of computational time

  6. Transport and diffusion of material quantities on propagating interfaces via level set methods

    CERN Document Server

    Adalsteinsson, D

    2003-01-01

    We develop theory and numerical algorithms to apply level set methods to problems involving the transport and diffusion of material quantities in a level set framework. Level set methods are computational techniques for tracking moving interfaces; they work by embedding the propagating interface as the zero level set of a higher dimensional function, and then approximate the solution of the resulting initial value partial differential equation using upwind finite difference schemes. The traditional level set method works in the trace space of the evolving interface, and hence disregards any parameterization in the interface description. Consequently, material quantities on the interface which themselves are transported under the interface motion are not easily handled in this framework. We develop model equations and algorithmic techniques to extend the level set method to include these problems. We demonstrate the accuracy of our approach through a series of test examples and convergence studies.

  7. Transport and diffusion of material quantities on propagating interfaces via level set methods

    International Nuclear Information System (INIS)

    Adalsteinsson, David; Sethian, J.A.

    2003-01-01

    We develop theory and numerical algorithms to apply level set methods to problems involving the transport and diffusion of material quantities in a level set framework. Level set methods are computational techniques for tracking moving interfaces; they work by embedding the propagating interface as the zero level set of a higher dimensional function, and then approximate the solution of the resulting initial value partial differential equation using upwind finite difference schemes. The traditional level set method works in the trace space of the evolving interface, and hence disregards any parameterization in the interface description. Consequently, material quantities on the interface which themselves are transported under the interface motion are not easily handled in this framework. We develop model equations and algorithmic techniques to extend the level set method to include these problems. We demonstrate the accuracy of our approach through a series of test examples and convergence studies

  8. A local level set method based on a finite element method for unstructured meshes

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, Long Cu; Choi, Hyoung Gwon [School of Mechanical Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2016-12-15

    A local level set method for unstructured meshes has been implemented by using a finite element method. A least-square weighted residual method was employed for implicit discretization to solve the level set advection equation. By contrast, a direct re-initialization method, which is directly applicable to the local level set method for unstructured meshes, was adopted to re-correct the level set function to become a signed distance function after advection. The proposed algorithm was constructed such that the advection and direct reinitialization steps were conducted only for nodes inside the narrow band around the interface. Therefore, in the advection step, the Gauss–Seidel method was used to update the level set function using a node-by-node solution method. Some benchmark problems were solved by using the present local level set method. Numerical results have shown that the proposed algorithm is accurate and efficient in terms of computational time.

  9. Reference hearing threshold levels for chirp signals delivered by an ER-3A insert earphone

    DEFF Research Database (Denmark)

    Gøtsche-Rasmussen, Kristian; Poulsen, Torben; Elberling, Claus

    2012-01-01

    back from a Tucker Davies Technologies System II, and a Matlab program controlled the test setup. The results are specified in dB peak-to-peak equivalent threshold sound pressure levels (dB peETSPL). Study sample: The test group consisted of 25 otologically-normal young adults (age 18–25 years......Objective: To establish reference hearing threshold levels for chirps and frequency-specific chirps. Design: Hearing thresholds were determined monaurally for broad-band chirps and octave-band chirps using the Etymotic Research, ER-3A insert earphone. The chirps were presented using two repetition...

  10. Age-specific reference values for serum FSH and estradiol levels throughout the reproductive period.

    Science.gov (United States)

    Grisendi, Valentina; Spada, Elena; Argento, Cindy; Plebani, Maddalena; Milani, Silvano; Seracchioli, Renato; Volpe, Annibale; La Marca, Antonio

    2014-06-01

    High serum day 3 FSH levels are associated with poor ovarian reserve and reduced fertility, but the interpretation of FSH values according to age is still not univocal. The purpose of this study was to determine age-dependent reference values in women with regular menstrual cycles and FSH as a guide for specialists. The study was performed at the Department of Mother-Infant of a University-based tertiary care centre. One-hundred ninety-two healthy normal menstruating women were recruited for the study. All patients attended the department on menstrual cycle day 3 for a blood sample for FSH and estradiol determination. A linear relationship between FSH or estradiol serum levels and age was observed. The FSH level increased by 0.11 IU for every year of age (1 IU for every 9 years of age). The values of FSH and estradiol corresponding to the 5th, 25th, 50th, 75th, 95th centiles for any specific age have been calculated. Serum FSH levels need to be interpreted according to age-dependent reference values. Serum FSH levels on 95th centile for any age may represent a warning sign for reduced ovarian reserve.

  11. Development of a Reference Data Set (RDS) for dental age estimation (DAE) and testing of this with a separate Validation Set (VS) in a southern Chinese population.

    Science.gov (United States)

    Jayaraman, Jayakumar; Wong, Hai Ming; King, Nigel M; Roberts, Graham J

    2016-10-01

    Many countries have recently experienced a rapid increase in the demand for forensic age estimates of unaccompanied minors. Hong Kong is a major tourist and business center where there has been an increase in the number of people intercepted with false travel documents. An accurate estimation of age is only possible when a dataset for age estimation that has been derived from the corresponding ethnic population. Thus, the aim of this study was to develop and validate a Reference Data Set (RDS) for dental age estimation for southern Chinese. A total of 2306 subjects were selected from the patient archives of a large dental hospital and the chronological age for each subject was recorded. This age was assigned to each specific stage of dental development for each tooth to create a RDS. To validate this RDS, a further 484 subjects were randomly chosen from the patient archives and their dental age was assessed based on the scores from the RDS. Dental age was estimated using meta-analysis command corresponding to random effects statistical model. Chronological age (CA) and Dental Age (DA) were compared using the paired t-test. The overall difference between the chronological and dental age (CA-DA) was 0.05 years (2.6 weeks) for males and 0.03 years (1.6 weeks) for females. The paired t-test indicated that there was no statistically significant difference between the chronological and dental age (p > 0.05). The validated southern Chinese reference dataset based on dental maturation accurately estimated the chronological age. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  12. Reference design and operations for deep borehole disposal of high-level radioactive waste

    International Nuclear Information System (INIS)

    Herrick, Courtney Grant; Brady, Patrick Vane; Pye, Steven; Arnold, Bill Walter; Finger, John Travis; Bauer, Stephen J.

    2011-01-01

    A reference design and operational procedures for the disposal of high-level radioactive waste in deep boreholes have been developed and documented. The design and operations are feasible with currently available technology and meet existing safety and anticipated regulatory requirements. Objectives of the reference design include providing a baseline for more detailed technical analyses of system performance and serving as a basis for comparing design alternatives. Numerous factors suggest that deep borehole disposal of high-level radioactive waste is inherently safe. Several lines of evidence indicate that groundwater at depths of several kilometers in continental crystalline basement rocks has long residence times and low velocity. High salinity fluids have limited potential for vertical flow because of density stratification and prevent colloidal transport of radionuclides. Geochemically reducing conditions in the deep subsurface limit the solubility and enhance the retardation of key radionuclides. A non-technical advantage that the deep borehole concept may offer over a repository concept is that of facilitating incremental construction and loading at multiple perhaps regional locations. The disposal borehole would be drilled to a depth of 5,000 m using a telescoping design and would be logged and tested prior to waste emplacement. Waste canisters would be constructed of carbon steel, sealed by welds, and connected into canister strings with high-strength connections. Waste canister strings of about 200 m length would be emplaced in the lower 2,000 m of the fully cased borehole and be separated by bridge and cement plugs. Sealing of the upper part of the borehole would be done with a series of compacted bentonite seals, cement plugs, cement seals, cement plus crushed rock backfill, and bridge plugs. Elements of the reference design meet technical requirements defined in the study. Testing and operational safety assurance requirements are also defined. Overall

  13. Reference design and operations for deep borehole disposal of high-level radioactive waste.

    Energy Technology Data Exchange (ETDEWEB)

    Herrick, Courtney Grant; Brady, Patrick Vane; Pye, Steven; Arnold, Bill Walter; Finger, John Travis; Bauer, Stephen J.

    2011-10-01

    A reference design and operational procedures for the disposal of high-level radioactive waste in deep boreholes have been developed and documented. The design and operations are feasible with currently available technology and meet existing safety and anticipated regulatory requirements. Objectives of the reference design include providing a baseline for more detailed technical analyses of system performance and serving as a basis for comparing design alternatives. Numerous factors suggest that deep borehole disposal of high-level radioactive waste is inherently safe. Several lines of evidence indicate that groundwater at depths of several kilometers in continental crystalline basement rocks has long residence times and low velocity. High salinity fluids have limited potential for vertical flow because of density stratification and prevent colloidal transport of radionuclides. Geochemically reducing conditions in the deep subsurface limit the solubility and enhance the retardation of key radionuclides. A non-technical advantage that the deep borehole concept may offer over a repository concept is that of facilitating incremental construction and loading at multiple perhaps regional locations. The disposal borehole would be drilled to a depth of 5,000 m using a telescoping design and would be logged and tested prior to waste emplacement. Waste canisters would be constructed of carbon steel, sealed by welds, and connected into canister strings with high-strength connections. Waste canister strings of about 200 m length would be emplaced in the lower 2,000 m of the fully cased borehole and be separated by bridge and cement plugs. Sealing of the upper part of the borehole would be done with a series of compacted bentonite seals, cement plugs, cement seals, cement plus crushed rock backfill, and bridge plugs. Elements of the reference design meet technical requirements defined in the study. Testing and operational safety assurance requirements are also defined. Overall

  14. Mapping of radio frequency electromagnetic field exposure levels in outdoor environment and comparing with reference levels for general public health.

    Science.gov (United States)

    Cansiz, Mustafa; Abbasov, Teymuraz; Kurt, M Bahattin; Celik, A Recai

    2018-03-01

    In this study, radio frequency electromagnetic field exposure levels were measured on the main streets in the city center of Diyarbakır, Turkey. Measured electric field levels were plotted on satellite imagery of Diyarbakır and were compared with exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Exposure measurements were performed in dense urban, urban and suburban areas each day for 7 consecutive days. The measurement system consisted of high precision and portable spectrum analyzer, three-axis electric field antenna, connection cable and a laptop which was used to record the measurement samples as a data logger. The highest exposure levels were detected for two places, which are called Diclekent and Batıkent. It was observed that the highest instantaneous electric field strength value for Batıkent was 7.18 V/m and for Diclekent was 5.81 V/m. It was statistically determined that the main contributor band to the total exposure levels was Universal Mobile Telecommunications System band. Finally, it was concluded that all measured exposure levels were lower than the reference levels recommended by ICNIRP for general public health.

  15. Natural setting of Japanese islands and geologic disposal of high-level waste

    International Nuclear Information System (INIS)

    Koide, Hitoshi

    1991-01-01

    The Japanese islands are a combination of arcuate islands along boundaries between four major plates: Eurasia, North America, Pacific and Philippine Sea plates. The interaction among the four plates formed complex geological structures which are basically patchworks of small blocks of land and sea-floor sediments piled up by the subduction of oceanic plates along the margin of the Eurasia continent. Although frequent earthquakes and volcanic eruptions clearly indicate active crustal deformation, the distribution of active faults and volcanoes is localized regionally in the Japanese islands. Crustal displacement faster than 1 mm/year takes place only in restricted regions near plate boundaries or close to major active faults. Volcanic activity is absent in the region between the volcanic front and the subduction zone. The site selection is especially important in Japan. The scenarios for the long-term performance assessment of high-level waste disposal are discussed with special reference to the geological setting of Japan. The long-term prediction of tectonic disturbance, evaluation of faults and fractures in rocks and estimation of long-term water-rock interaction are key issues in the performance assessment of the high-level waste disposal in the Japanese islands. (author)

  16. Certification & validation of biosafety level-2 & biosafety level-3 laboratories in Indian settings & common issues

    OpenAIRE

    Devendra T Mourya; Pragya D Yadav; Ajay Khare; Anwar H Khan

    2017-01-01

    With increasing awareness regarding biorisk management worldwide, many biosafety laboratories are being setup in India. It is important for the facility users, project managers and the executing agencies to understand the process of validation and certification of such biosafety laboratories. There are some international guidelines available, but there are no national guidelines or reference standards available in India on certification and validation of biosafety laboratories. There is no ac...

  17. Translating evidence into practice: Hong Kong Reference Framework for Preventive Care for Children in Primary Care Settings.

    Science.gov (United States)

    Siu, Natalie P Y; Too, L C; Tsang, Caroline S H; Young, Betty W Y

    2015-06-01

    There is increasing evidence that supports the close relationship between childhood and adult health. Fostering healthy growth and development of children deserves attention and effort. The Reference Framework for Preventive Care for Children in Primary Care Settings has been published by the Task Force on Conceptual Model and Preventive Protocols under the direction of the Working Group on Primary Care. It aims to promote health and prevent disease in children and is based on the latest research, and contributions of the Clinical Advisory Group that comprises primary care physicians, paediatricians, allied health professionals, and patient groups. This article highlights the comprehensive, continuing, and patient-centred preventive care for children and discusses how primary care physicians can incorporate the evidence-based recommendations into clinical practice. It is anticipated that the adoption of this framework will contribute to improved health and wellbeing of children.

  18. Dose limits, constraints, reference levels. What does it mean for radiation protection?

    International Nuclear Information System (INIS)

    Breckow, J.

    2016-01-01

    The established concept of radiation protection with its basic principles justification, optimization, and limitation has proved its value and is going to be continued. In its deeper meaning, however, the concept is rather subtle and complex. Furthermore, in some aspects there remain some breaches or inconsistencies. This is just true for the terms dose limit, reference lever, and constraint that are tightly associated with the radiation protection principles. In order to guarantee the ability of radiation protection in whole extent, the subtle differences of meaning have to be communicated. There is a permanent need to defend the conceptual function of these terms against deliberate or undeliberate misinterpretations. Reference levels are definitely not the same as dose limits and they may not be misused as such. Any attempt to misinterpret fundamental radiation protection principles for selfish purposes should discouraged vigorously.

  19. Time-Dependent Selection of an Optimal Set of Sources to Define a Stable Celestial Reference Frame

    Science.gov (United States)

    Le Bail, Karine; Gordon, David

    2010-01-01

    Temporal statistical position stability is required for VLBI sources to define a stable Celestial Reference Frame (CRF) and has been studied in many recent papers. This study analyzes the sources from the latest realization of the International Celestial Reference Frame (ICRF2) with the Allan variance, in addition to taking into account the apparent linear motions of the sources. Focusing on the 295 defining sources shows how they are a good compromise of different criteria, such as statistical stability and sky distribution, as well as having a sufficient number of sources, despite the fact that the most stable sources of the entire ICRF2 are mostly in the Northern Hemisphere. Nevertheless, the selection of a stable set is not unique: studying different solutions (GSF005a and AUG24 from GSFC and OPA from the Paris Observatory) over different time periods (1989.5 to 2009.5 and 1999.5 to 2009.5) leads to selections that can differ in up to 20% of the sources. Observing, recording, and network improvement are some of the causes, showing better stability for the CRF over the last decade than the last twenty years. But this may also be explained by the assumption of stationarity that is not necessarily right for some sources.

  20. Local diagnostic reference levels at the Portuguese Institute of oncology francisco gentil of coimbra

    Energy Technology Data Exchange (ETDEWEB)

    Bras, S.; Sousa, M.C. de [Algarve Univ., LIP-Algarve, FCT (Portugal); Lopes, M.C. [IPOFG-CROC, S.A., Medical Physics Dept., Coimbra (Portugal)

    2006-07-01

    In the scope of medical radiological exposures and according to European recommendations and national legal requirements [14], the maximum responsible for an installation must assure the establishment of local dose levels for each type of radiological examination and also assure that they are available for the doctor who prescribes the examination. In the absence of national reference dose levels, the so called Local Diagnostic Reference Levels (L.D.R.L.) should be in agreement with the European Diagnostic Reference Levels published for the different types of medical exposures. The aim of this work was to establish a protocol of measurement for each type of more frequent examination, namely in conventional radiology, in CT and in mammography performed in our hospital. For each kind of examination the recommended dose descriptor was adopted and directly measured or derived from basic charge measurements. The patient sample corresponded in each case to at least a minimum of 10 standard-sized patients, as recommended, in order to obtain averages that constitute for each type of radiological examination the L.D.R.L. that could be compared with the European D.R.L.. The results obtained are in the large majority of the situations below the corresponding D.R.L.. Nevertheless we have identified some situations that deserve more attention.In conventional radiology all L.D.R.L. are below the reference levels. However we have detected some skull post anterior (skull P.A.) exposures where entrance skin doses exceeded the standard value. This may be due to equipment age problems but, as always, improvement of staff education will contribute to better practices and we hope that this work can contribute to this objective. In CT the L.D.R.L. that corresponds to single slice scan meet the standards whereas complete examinations described by dose length product (D.L.P.) values show a larger variation and also some situations where the reference level is exceeded. It is possible that

  1. Local diagnostic reference levels at the Portuguese Institute of oncology francisco gentil of coimbra

    International Nuclear Information System (INIS)

    Bras, S.; Sousa, M.C. de; Lopes, M.C.

    2006-01-01

    In the scope of medical radiological exposures and according to European recommendations and national legal requirements [14], the maximum responsible for an installation must assure the establishment of local dose levels for each type of radiological examination and also assure that they are available for the doctor who prescribes the examination. In the absence of national reference dose levels, the so called Local Diagnostic Reference Levels (L.D.R.L.) should be in agreement with the European Diagnostic Reference Levels published for the different types of medical exposures. The aim of this work was to establish a protocol of measurement for each type of more frequent examination, namely in conventional radiology, in CT and in mammography performed in our hospital. For each kind of examination the recommended dose descriptor was adopted and directly measured or derived from basic charge measurements. The patient sample corresponded in each case to at least a minimum of 10 standard-sized patients, as recommended, in order to obtain averages that constitute for each type of radiological examination the L.D.R.L. that could be compared with the European D.R.L.. The results obtained are in the large majority of the situations below the corresponding D.R.L.. Nevertheless we have identified some situations that deserve more attention.In conventional radiology all L.D.R.L. are below the reference levels. However we have detected some skull post anterior (skull P.A.) exposures where entrance skin doses exceeded the standard value. This may be due to equipment age problems but, as always, improvement of staff education will contribute to better practices and we hope that this work can contribute to this objective. In CT the L.D.R.L. that corresponds to single slice scan meet the standards whereas complete examinations described by dose length product (D.L.P.) values show a larger variation and also some situations where the reference level is exceeded. It is possible that

  2. An efficient, scalable, and adaptable framework for solving generic systems of level-set PDEs

    Directory of Open Access Journals (Sweden)

    Kishore R. Mosaliganti

    2013-12-01

    Full Text Available In the last decade, level-set methods have been actively developed for applications in image registration, segmentation, tracking, and reconstruction. However, the development of a wide variety of level-set PDEs and their numerical discretization schemes, coupled with hybrid combinations of PDE terms, stopping criteria, and reinitialization strategies, has created a software logistics problem. In the absence of an integrative design, current toolkits support only specific types of level-set implementations which restrict future algorithm development since extensions require significant code duplication and effort. In the new NIH/NLM Insight Toolkit (ITK v4 architecture, we implemented a level-set software design that is flexible to different numerical (continuous, discrete, and sparse and grid representations (point, mesh, and image-based. Given that a generic PDE is a summation of different terms, we used a set of linked containers to which level-set terms can be added or deleted at any point in the evolution process. This container-based approach allows the user to explore and customize terms in the level-set equation at compile-time in a flexible manner. The framework is optimized so that repeated computations of common intensity functions (e.g. gradient and Hessians across multiple terms is eliminated. The framework further enables the evolution of multiple level-sets for multi-object segmentation and processing of large datasets. For doing so, we restrict level-set domains to subsets of the image domain and use multithreading strategies to process groups of subdomains or level-set functions. Users can also select from a variety of reinitialization policies and stopping criteria. Finally, we developed a visualization framework that shows the evolution of a level-set in real-time to help guide algorithm development and parameter optimization. We demonstrate the power of our new framework using confocal microscopy images of cells in a

  3. A comparison and cross-reference of commercial low-level radioactive waste acceptance criteria

    International Nuclear Information System (INIS)

    Kerr, T.A.

    1997-04-01

    This document, prepared by the National Low-Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory, is a comparison and cross-reference of commercial low-level radioactive waste acceptance criteria. Many of these are draft or preliminary criteria as well as implemented criteria at operating low-level radioactive waste management facilities. Waste acceptance criteria from the following entities are included: US Nuclear Regulatory Commission, South Carolina, Washington, Utah, Nevada, California, illinois, Texas, North Carolina, Nebraska, Pennsylvania, New York, and the Midwest Compact Region. Criteria in the matrix include the following: physical form, chemical form, liquid limits, void space in packages, concentration averaging, types of packaging, chelating agents, solidification media, stability requirements, sorptive media, gas, oil, biological waste, pyrophorics, source material, special nuclear material, package dimensions, incinerator ash, dewatered resin, transuranics, and mixed waste. Each criterion in the matrix is cross-referenced to its source document so that exact requirements can be determined

  4. A LEVEL SET BASED SHAPE OPTIMIZATION METHOD FOR AN ELLIPTIC OBSTACLE PROBLEM

    KAUST Repository

    Burger, Martin; Matevosyan, Norayr; Wolfram, Marie-Therese

    2011-01-01

    analysis of the level set method in terms of viscosity solutions. To our knowledge this is the first complete analysis of a level set method for a nonlocal shape optimization problem. Finally, we discuss the implementation of the methods and illustrate its

  5. A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS.

    Science.gov (United States)

    Almén, Anja; Båth, Magnus

    2016-06-01

    The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Diagnostic reference levels in intraoral radiology: From the laboratory to clinical practice

    International Nuclear Information System (INIS)

    Alcaraz, M.; Velasco, E.; Martinez-Beneyto, Y.; Velasco, F.; Parra, C.; Canteras, M.

    2010-01-01

    To determine the diagnostic reference levels (DRLs) for obtaining a diagnostic image in the normal conditions of clinical practice and to explain the differences between the levels found and the DRLs obtained in other experimental conditions, suggesting that there has been a reduction in the European Union (EU) recommended levels. A total of 2296 official reports on dental surgeries from 16 Spanish autonomous regions compiled during 2008 were studied. A mean DRL of 3.3 mGy was determined: 2.6 mGy for installations using direct digital systems, 3.4 mGy for those using indirect systems, 4.4 mGy for those using Ultra-speed film and 3.7 mGy for those using Insight. The DRLs found in this survey are below the EU recommended values but far above previously described values, possibly because all the different systems were considered and because values refer to those of the normal work conditions of clinical practice. (authors)

  7. A conceptual framework for managing radiation dose to patients in diagnostic radiology using reference dose levels

    International Nuclear Information System (INIS)

    Almen, Anja; Baath, Magnus

    2016-01-01

    The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. (authors)

  8. Preliminary Diagnostic Reference Levels of Adult CT at Aristide Ledantec National Hospital

    International Nuclear Information System (INIS)

    Diagne, M.; Gning, F.; Dieng, M. M.; Gueye, L.

    2015-01-01

    The number of Computed Tomography (CT) procedures performed in Senegal has widely increased as the CT is a powerful tool for the accurate and effective diagnosis. CT is a diagnostic imaging modality giving higher patient dose in comparison with other radiological procedures. The establishing of diagnostic reference levels (DRLs) is a way to optimize the radiation arising from CT procedures to as low as reasonable (ALARA) and to ensure good practice. Objective: The purpose of this study is to establish Local Diagnostic Reference Levels (LDRLs) at the University Hospital of Aristide LeDantec for CT examinations and to compare these values with the international Diagnostic Reference Levels (DRLs) to benchmark the local practice. Materials/Methods: This was a cross-sectional survey carried out in HALD between August 2014 and January 2015. Demographic data and acquisition parameters of 700 CT scan examinations performed on adult patients were collected from request forms and CT scan consoles. The values of CTDIw, CTDIvol and DLP were calculated using ImPACT (Imaging Performance and Assessment of Computed Tomography) software for Siemens Definition AS scanner of HALD. This was done by correlating the measurements from the National Radiological Protection Board (NRPB–R250) scanners with the effective dose calculated, using the CT–EXPO software. Data was analyzed using mean, range, 3rd quartile, as well as mean. Frequency tables and histogrammes were used to summarise the data. Results: The 3rd quartile doses in this study for head, chest, abdomen and pelvis were 89 mGy, 12 mGy, 16.5 mGy, and 15 mGy, respectively. These values were in good agreement with the values reported from the literature. (author)

  9. Dose evaluation and establishment of reference levels in activity for nuclear medicine

    International Nuclear Information System (INIS)

    Ribeiro, Julio Cesar de Souza

    2017-01-01

    The International Commission on Radiation Protection (ICRP) has emphasized the importance of accurately determining the mean dose levels, or administered activity, received by the patients for each medical procedure that uses ionizing radiation. However, the number of bibliographic references addressing the need to know and optimize these levels is insufficient, or rather limited, which may lead to non-standardizes techniques, a lack of exposures control, and also the increase of associated radiological risks of these procedures. In this context, a software in Visual Basic® of Microsoft© language was developed whose function is to elaborate a method of obtaining the Reference Levels in Activity (RLA) for nuclear medicine patients by determining the third quartile of the examinations carried out. The program also allows obtaining absorbed dose values in critical organs based on patient specificities as age, sex and Body Mass Index (BMI) in order to evaluate the risk involved in each procedure. The main nuclear medicine diagnostic procedures were evaluated through the database of two public hospitals and a private clinic, obtaining the NRAs of each facility, where the software was validated by comparison with the traditionally accepted calculation methods. Due to the results obtained in each installation, in addition to NRA determination, gaps in treatment capacities and unjustified dose variations for the same procedure were identified, indicating the need for optimization. Thus, the developed program is able to provide the estimated values of effective and absorbed doses involved in each procedure, for each patient, providing reference values for nuclear medicine field, not available in the national scenario so far. (author)

  10. Technology, Safety and Costs of Decommissioning a Reference Low-Level Waste Burial Ground. Appendices

    International Nuclear Information System (INIS)

    None

    1980-01-01

    Safety and cost information are developed for the conceptual decommissioning of commercial low-level waste (LLW) burial grounds. Two generic burial grounds, one located on an arid western site and the other located on a humid eastern site, are used as reference facilities for the study. The two burial grounds are assumed to have the same site capacity for waste, the same radioactive waste inventory, and similar trench characteristics and operating procedures. The climate, geology. and hydrology of the two sites are chosen to be typical of real western and eastern sites. Volume 2 (Appendices) contains the detailed analyses and data needed to support the results given in Volume 1.

  11. DEVELOPMENT OF DIAGNOSTIC REFERENCE LEVELS (DRL OF PATIENTS X-RAY EXPOSURE IN DIAGNOSTIC RADIOLOGY

    Directory of Open Access Journals (Sweden)

    A. V. Vodovatov

    2013-01-01

    Full Text Available We introduce a system of Diagnostic Reference Levels (DRLs for patients medical exposure for national health care practice implementation. DRLs are an effective way of the patient radiation protection through the optimization of the medical exposure. The paper discusses and compares different methods of determining the DRLs based on measured and/or calculated quantities of patient’s dose: dose area product (DAP, entrance surface dose (ESD and an effective dose. Distributions of different dose quantities in different Saint-Petersburg clinics are shown on the example of chest PA examinations. The results are compared with the data from other sources. Regional DRLs for Saint-Petersburg are proposed.

  12. Technology, Safety and Costs of Decommissioning a Reference Low-Level Waste Burial Ground. Main Report

    International Nuclear Information System (INIS)

    Murphy, E. S.; Holter, G. M.

    1980-01-01

    Safety and cost information are developed for the conceptual decommissioning of commercial low-level waste (LLW) burial grounds. Two generic burial grounds, one located on an arid western site and the other located on a humid eastern site, are used as reference facilities for the study. The two burial grounds are assumed to have the same site capacity for waste, the same radioactive waste inventory, and similar trench characteristics and operating procedures. The climate, geology. and hydrology of the two sites are chosen to be typical of real western and eastern sites. Volume 1 (Main Report) contains background information and study results in summary form.

  13. Technology, Safety and Costs of Decommissioning a Reference Low-Level Waste Burial Ground. Main Report

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, E. S.; Holter, G. M.

    1980-06-01

    Safety and cost information are developed for the conceptual decommissioning of commercial low-level waste (LLW) burial grounds. Two generic burial grounds, one located on an arid western site and the other located on a humid eastern site, are used as reference facilities for the study. The two burial grounds are assumed to have the same site capacity for waste, the same radioactive waste inventory, and similar trench characteristics and operating procedures. The climate, geology. and hydrology of the two sites are chosen to be typical of real western and eastern sites. Volume 1 (Main Report) contains background information and study results in summary form.

  14. Children's level of word knowledge predicts their exclusion of familiar objects as referents of novel words

    Directory of Open Access Journals (Sweden)

    Susanne eGrassmann

    2015-08-01

    Full Text Available When children are learning a novel object label, they tend to exclude as possible referents familiar objects for which they already have a name. In the current study, we wanted to know if children would behave in this same way regardless of how well they knew the name of potential referent objects, specifically, whether they could only comprehend it or they could both comprehend and produce it. Sixty-six monolingual German-speaking 2-, 3-, and 4-year-old children participated in two experimental sessions. In one session the familiar objects were chosen such that their labels were in the children's productive vocabularies, and in the other session the familiar objects were chosen such that their labels were only in the children's receptive vocabularies. Results indicated that children at all three ages were more likely to exclude a familiar object as the potential referent of the novel word if they could comprehend and produce its name rather than comprehend its name only. Indeed, level of word knowledge as operationalized in this way was a better predictor than was age. These results are discussed in the context of current theories of word learning by exclusion.

  15. Certification & validation of biosafety level-2 & biosafety level-3 laboratories in Indian settings & common issues.

    Science.gov (United States)

    Mourya, Devendra T; Yadav, Pragya D; Khare, Ajay; Khan, Anwar H

    2017-10-01

    With increasing awareness regarding biorisk management worldwide, many biosafety laboratories are being setup in India. It is important for the facility users, project managers and the executing agencies to understand the process of validation and certification of such biosafety laboratories. There are some international guidelines available, but there are no national guidelines or reference standards available in India on certification and validation of biosafety laboratories. There is no accredited government/private agency available in India to undertake validation and certification of biosafety laboratories. Therefore, the reliance is mostly on indigenous experience, talent and expertise available, which is in short supply. This article elucidates the process of certification and validation of biosafety laboratories in a concise manner for the understanding of the concerned users and suggests the important parameters and criteria that should be considered and addressed during the laboratory certification and validation process.

  16. Certification & validation of biosafety level-2 & biosafety level-3 laboratories in Indian settings & common issues

    Directory of Open Access Journals (Sweden)

    Devendra T Mourya

    2017-01-01

    Full Text Available With increasing awareness regarding biorisk management worldwide, many biosafety laboratories are being setup in India. It is important for the facility users, project managers and the executing agencies to understand the process of validation and certification of such biosafety laboratories. There are some international guidelines available, but there are no national guidelines or reference standards available in India on certification and validation of biosafety laboratories. There is no accredited government/private agency available in India to undertake validation and certification of biosafety laboratories. Therefore, the reliance is mostly on indigenous experience, talent and expertise available, which is in short supply. This article elucidates the process of certification and validation of biosafety laboratories in a concise manner for the understanding of the concerned users and suggests the important parameters and criteria that should be considered and addressed during the laboratory certification and validation process.

  17. Regional Diagnostic Reference Levels and Collective Effective Doses from Computed Tomography (CT) Scanners in India

    International Nuclear Information System (INIS)

    Livingstone, R.S.; Dinakaran, P.M.

    2011-01-01

    Diagnostic examinations performed using computed tomography (CT) are on the increase, and the use of this modality needs to be monitored periodically. The aim of this study was to formulate regional diagnostic reference levels (DRLs) and assess collective effective doses from CT scanners in Tamil Nadu, India. In-site CT dose measurements were performed for 127 CT scanners in Tamil Nadu as a part of the Atomic Energy Regulatory Board (AERB) funded project for a period of two years. Regional DRLs were formulated at third quartile level for three CT protocols such as thorax, abdomen and pelvis and were found to be 557 mGy.cm, 521 mGy.cm and 294 mGy.cm, respectively. The collective effective dose in Tamil Nadu was found to be 14.93 man Sv per day. (author)

  18. Establishment of multi-slice computed tomography (MSCT) reference level in Johor, Malaysia

    Science.gov (United States)

    Karim, M. K. A.; Hashim, S.; Bakar, K. A.; Muhammad, H.; Sabarudin, A.; Ang, W. C.; Bahruddin, N. A.

    2016-03-01

    Radiation doses from computed tomography (CT) are the highest and most hazardous compared to other imaging modalities. This study aimed to evaluate radiation dose in Johor, Malaysia to patients during computed tomography examinations of the brain, chest and abdomen and to establish the local diagnostic reference levels (DRLs) as are present with the current, state- of-art, multi-slice CT scanners. Survey forms were sent to five centres performing CT to obtain data regarding acquisition parameters as well as the dose information from CT consoles. CT- EXPO (Version 2.3.1, Germany) was used to validate the dose information. The proposed DRLs were indicated by rounding the third quartiles of whole dose distributions where mean values of CTDIw (mGy), CTDIvol (mGy) and DLP (mGy.cm) were comparable with other reference levels; 63, 63, and 1015 respectively for CT Brain; 15, 14, and 450 respectively for CT thorax and 16, 17, and 590 respectively for CT abdomen. The study revealed that the CT practice and dose output were revolutionised, and must keep up with the pace of introductory technology. We suggest that CTDIvol should be included in current national DRLs, as modern CTs are configured with a higher number of detectors and are independent of pitch factors.

  19. Establishment of multi-slice computed tomography (MSCT) reference level in Johor, Malaysia

    International Nuclear Information System (INIS)

    Karim, M K A; Hashim, S; Ang, W C; Bahruddin, N A; Bakar, K A; Muhammad, H; Sabarudin, A

    2016-01-01

    Radiation doses from computed tomography (CT) are the highest and most hazardous compared to other imaging modalities. This study aimed to evaluate radiation dose in Johor, Malaysia to patients during computed tomography examinations of the brain, chest and abdomen and to establish the local diagnostic reference levels (DRLs) as are present with the current, state- of-art, multi-slice CT scanners. Survey forms were sent to five centres performing CT to obtain data regarding acquisition parameters as well as the dose information from CT consoles. CT- EXPO (Version 2.3.1, Germany) was used to validate the dose information. The proposed DRLs were indicated by rounding the third quartiles of whole dose distributions where mean values of CTDI w (mGy), CTDI vol (mGy) and DLP (mGy.cm) were comparable with other reference levels; 63, 63, and 1015 respectively for CT Brain; 15, 14, and 450 respectively for CT thorax and 16, 17, and 590 respectively for CT abdomen. The study revealed that the CT practice and dose output were revolutionised, and must keep up with the pace of introductory technology. We suggest that CTDI vol should be included in current national DRLs, as modern CTs are configured with a higher number of detectors and are independent of pitch factors. (paper)

  20. Exhaled nitric oxide levels in asthma: Personal best versus reference values.

    Science.gov (United States)

    Smith, Andrew D; Cowan, Jan O; Taylor, D Robin

    2009-10-01

    Factors affecting the fraction of nitric oxide in exhaled air (FE(NO)) are multiple. Interpreting values when assessing airways disease may be problematic. Clinically optimum levels have not been defined. We aimed to establish the relationship between predicted values for FE(NO) obtained from equations by Olin et al, Travers et al, and Dressel et al, and normalized levels after oral prednisone. We also compared postprednisone FE(NO) levels with those obtained during optimized treatment with inhaled fluticasone. Data were obtained before and after a trial of oral prednisone (30mg/d for 14 days), and also from a previously published study in which patients had their dose of inhaled corticosteroid adjusted using either FE(NO) or symptoms/lung function to optimize treatment. Seventy-three patients completed the study. The geometric mean FE(NO) after prednisone (17.7 parts per billion [ppb]; 95% CI, 15.5-20.2) was significantly lower than mean FE(NO) at the optimized fluticasone dose (20.2 ppb; 95% CI, 17.1-23.8; P=.04) and at loss of control (27.6 ppb; 95% CI, 22.8-33.4; P values of Olin et al (16.8 ppb, 95% CI, 16.0-17.5; P=.44), but were significantly lower than values of Travers et al (predicted, 21.5 ppb; 95% CI, 20.9-22.2; P=.005) and Dressel et al (predicted, 27.8 ppb; 95% CI, 26.7-28.9; P values from the reference equation by Olin et al. However, at optimized doses of inhaled corticosteroid, although FE(NO) levels were higher than predicted, asthma was well controlled. Targeting FE(NO) on reference values is not justified.

  1. 23 CFR Appendix A to Part 772 - National Reference Energy Mean Emission Levels as a Function of Speed

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false National Reference Energy Mean Emission Levels as a Function of Speed A Appendix A to Part 772 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF... NOISE Pt. 772, App. A Appendix A to Part 772—National Reference Energy Mean Emission Levels as a...

  2. A level set approach for shock-induced α-γ phase transition of RDX

    Science.gov (United States)

    Josyula, Kartik; Rahul; De, Suvranu

    2018-02-01

    We present a thermodynamically consistent level sets approach based on regularization energy functional which can be directly incorporated into a Galerkin finite element framework to model interface motion. The regularization energy leads to a diffusive form of flux that is embedded within the level sets evolution equation which maintains the signed distance property of the level set function. The scheme is shown to compare well with the velocity extension method in capturing the interface position. The proposed level sets approach is employed to study the α-γphase transformation in RDX single crystal shocked along the (100) plane. Example problems in one and three dimensions are presented. We observe smooth evolution of the phase interface along the shock direction in both models. There is no diffusion of the interface during the zero level set evolution in the three dimensional model. The level sets approach is shown to capture the characteristics of the shock-induced α-γ phase transformation such as stress relaxation behind the phase interface and the finite time required for the phase transformation to complete. The regularization energy based level sets approach is efficient, robust, and easy to implement.

  3. Dose reference levels in Spanish intraoral dental radiology: stabilisation of the incorporation of digital systems in dental clinical practices

    International Nuclear Information System (INIS)

    Alcaraz, M.; Velasco, F.; Olivares, A.; Velasco, E.; Canteras, M.

    2016-01-01

    A total of 34 044 official quality assurance reports in dental radiodiagnostic surgery from 16 regions of Spain, compiled from 2002 to 2014, were studied in order to determine the progress of diagnostic reference levels (DRLs) for obtaining diagnostic images under normal conditions for clinical practice in Spanish dental clinics. A DRL of 2.8 mGy was set in 2014, which represents a 41.7 % decrease compared with that of 2002 (4.8 mGy). Over the same time period, the mean dose fell by 55.2 %. However, over the last 3 y, the stabilisation of the mean dose administered to patients has been observed with only a 6.7 % reduction in DRLs, which corresponds to the stabilisation of dental radiodiagnostic surgery on replacing the use of radiographic film with digital imaging systems. (authors)

  4. Hybrid approach for detection of dental caries based on the methods FCM and level sets

    Science.gov (United States)

    Chaabene, Marwa; Ben Ali, Ramzi; Ejbali, Ridha; Zaied, Mourad

    2017-03-01

    This paper presents a new technique for detection of dental caries that is a bacterial disease that destroys the tooth structure. In our approach, we have achieved a new segmentation method that combines the advantages of fuzzy C mean algorithm and level set method. The results obtained by the FCM algorithm will be used by Level sets algorithm to reduce the influence of the noise effect on the working of each of these algorithms, to facilitate level sets manipulation and to lead to more robust segmentation. The sensitivity and specificity confirm the effectiveness of proposed method for caries detection.

  5. Out-of-Core Computations of High-Resolution Level Sets by Means of Code Transformation

    DEFF Research Database (Denmark)

    Christensen, Brian Bunch; Nielsen, Michael Bang; Museth, Ken

    2012-01-01

    We propose a storage efficient, fast and parallelizable out-of-core framework for streaming computations of high resolution level sets. The fundamental techniques are skewing and tiling transformations of streamed level set computations which allow for the combination of interface propagation, re...... computations are now CPU bound and consequently the overall performance is unaffected by disk latency and bandwidth limitations. We demonstrate this with several benchmark tests that show sustained out-of-core throughputs close to that of in-core level set simulations....

  6. Level set segmentation of medical images based on local region statistics and maximum a posteriori probability.

    Science.gov (United States)

    Cui, Wenchao; Wang, Yi; Lei, Tao; Fan, Yangyu; Feng, Yan

    2013-01-01

    This paper presents a variational level set method for simultaneous segmentation and bias field estimation of medical images with intensity inhomogeneity. In our model, the statistics of image intensities belonging to each different tissue in local regions are characterized by Gaussian distributions with different means and variances. According to maximum a posteriori probability (MAP) and Bayes' rule, we first derive a local objective function for image intensities in a neighborhood around each pixel. Then this local objective function is integrated with respect to the neighborhood center over the entire image domain to give a global criterion. In level set framework, this global criterion defines an energy in terms of the level set functions that represent a partition of the image domain and a bias field that accounts for the intensity inhomogeneity of the image. Therefore, image segmentation and bias field estimation are simultaneously achieved via a level set evolution process. Experimental results for synthetic and real images show desirable performances of our method.

  7. A LEVEL SET BASED SHAPE OPTIMIZATION METHOD FOR AN ELLIPTIC OBSTACLE PROBLEM

    KAUST Repository

    Burger, Martin

    2011-04-01

    In this paper, we construct a level set method for an elliptic obstacle problem, which can be reformulated as a shape optimization problem. We provide a detailed shape sensitivity analysis for this reformulation and a stability result for the shape Hessian at the optimal shape. Using the shape sensitivities, we construct a geometric gradient flow, which can be realized in the context of level set methods. We prove the convergence of the gradient flow to an optimal shape and provide a complete analysis of the level set method in terms of viscosity solutions. To our knowledge this is the first complete analysis of a level set method for a nonlocal shape optimization problem. Finally, we discuss the implementation of the methods and illustrate its behavior through several computational experiments. © 2011 World Scientific Publishing Company.

  8. Low-level radioactive waste technology: a selected, annotated bibliography. [416 references

    Energy Technology Data Exchange (ETDEWEB)

    Fore, C.S.; Carrier, R.F.; Brewster, R.H.; Hyder, L.K.; Barnes, K.A.

    1981-10-01

    This annotated bibliography of 416 references represents the third in a series to be published by the Hazardous Materials Information Center containing scientific, technical, economic, and regulatory information relevant to low-level radioactive waste technology. The bibliography focuses on disposal site, environmental transport, and waste treatment studies as well as general reviews on the subject. The publication covers both domestic and foreign literature for the period 1951 to 1981. Major chapters selected are Chemical and Physical Aspects; Container Design and Performance; Disposal Site; Environmental Transport; General Studies and Reviews; Geology, Hydrology, and Site Resources; Regulatory and Economic Aspects; Social Aspects; Transportation Technology; Waste Production; and Waste Treatment. Entries in each of the chapters are further classified as a field study, laboratory study, theoretical study, or general overview involving one or more of these research areas.

  9. 1-GWh diurnal load-leveling superconducting magnetic energy storage system reference design

    International Nuclear Information System (INIS)

    Hassenzahl, W.V.; Rogers, J.D.

    1979-01-01

    A point reference design has been completed for a 1-GWh Superconducting Magnetic Energy Storage system. The system is for electric utility dirunal load leveling; however, such a device will function to meet much faster power demands including dynamic stabilization. The study has explored several concepts of design not previously considered in the same detail as treated here. Because the study is for a point design, optimization in all respects is not complete. The study examines aspects of the coil design; superconductor supported off of the dewar shell; the dewar shell, its configuration and stresses; the underground excavation and related construction for holding the superconducting coil and its dewar; the helium refrigeration system; the electrical converter system; the vacuum system; the guard coil; and the costs. The report is a condensation of the more comprehensive study which is in the process of being printed

  10. Nanosecond-level time synchronization of AERA using a beacon reference transmitter and commercial airplanes

    Directory of Open Access Journals (Sweden)

    Huege Tim

    2017-01-01

    Full Text Available Radio detection of cosmic-ray air showers requires time synchronization of detectors on a nanosecond level, especially for advanced reconstruction algorithms based on the wavefront curvature and for interferometric analysis approaches. At the Auger Engineering Radio Array, the distributed, autonomous detector stations are time-synchronized via the Global Positioning System which, however, does not provide sufficient timing accuracy. We thus employ a dedicated beacon reference transmitter to correct for eventby-event clock drifts in our offline data analysis. In an independent cross-check of this “beacon correction” using radio pulses emitted by commercial airplanes, we have shown that the combined timing accuracy of the two methods is better than 2 nanoseconds.

  11. Nanosecond-level time synchronization of AERA using a beacon reference transmitter and commercial airplanes

    Science.gov (United States)

    Huege, Tim

    2017-03-01

    Radio detection of cosmic-ray air showers requires time synchronization of detectors on a nanosecond level, especially for advanced reconstruction algorithms based on the wavefront curvature and for interferometric analysis approaches. At the Auger Engineering Radio Array, the distributed, autonomous detector stations are time-synchronized via the Global Positioning System which, however, does not provide sufficient timing accuracy. We thus employ a dedicated beacon reference transmitter to correct for eventby-event clock drifts in our offline data analysis. In an independent cross-check of this "beacon correction" using radio pulses emitted by commercial airplanes, we have shown that the combined timing accuracy of the two methods is better than 2 nanoseconds.

  12. An accurate conservative level set/ghost fluid method for simulating turbulent atomization

    International Nuclear Information System (INIS)

    Desjardins, Olivier; Moureau, Vincent; Pitsch, Heinz

    2008-01-01

    This paper presents a novel methodology for simulating incompressible two-phase flows by combining an improved version of the conservative level set technique introduced in [E. Olsson, G. Kreiss, A conservative level set method for two phase flow, J. Comput. Phys. 210 (2005) 225-246] with a ghost fluid approach. By employing a hyperbolic tangent level set function that is transported and re-initialized using fully conservative numerical schemes, mass conservation issues that are known to affect level set methods are greatly reduced. In order to improve the accuracy of the conservative level set method, high order numerical schemes are used. The overall robustness of the numerical approach is increased by computing the interface normals from a signed distance function reconstructed from the hyperbolic tangent level set by a fast marching method. The convergence of the curvature calculation is ensured by using a least squares reconstruction. The ghost fluid technique provides a way of handling the interfacial forces and large density jumps associated with two-phase flows with good accuracy, while avoiding artificial spreading of the interface. Since the proposed approach relies on partial differential equations, its implementation is straightforward in all coordinate systems, and it benefits from high parallel efficiency. The robustness and efficiency of the approach is further improved by using implicit schemes for the interface transport and re-initialization equations, as well as for the momentum solver. The performance of the method is assessed through both classical level set transport tests and simple two-phase flow examples including topology changes. It is then applied to simulate turbulent atomization of a liquid Diesel jet at Re=3000. The conservation errors associated with the accurate conservative level set technique are shown to remain small even for this complex case

  13. An approach to local diagnostic reference levels (DRL's) in the context of national and international DRL's

    International Nuclear Information System (INIS)

    Rogers, A.T.

    2001-01-01

    In recent years there has been a greater focus on the management of patient doses. This effort has been driven by the realisation of both the increasing magnitude of patient doses and their variation both intra- and inter-nationally. Legislators and guidance-issuing bodies have developed the idea of 'Diagnostic Reference Levels' (DRL's). In particular, the European Union, in their Council Directive 97/43/Euratom, required Member States to develop DRL's. The UK Government, when consolidating this EU Directive into UK legislation, extended the concept of DRL's from a national to an employer level. However, the methodologies used for development of national and international DRL's do not translate to a local level and hence a new approach is required. This paper describes one particular approach made by a UK hospital to introduce 'Local DRL's' in such a manner as to aid the optimisation process. This approach utilises a dose index, based on the local patient population, which is monitored for trends. Any trend in patient dose triggers an investigation linked to the clinical audit system within the Clinical Radiology Department. It is the audit cycle that ensures a continuing move towards an optimised situation. Additional triggers may be employed such as large patient dose variations. (author)

  14. Radioactivity reference levels in ceramics tiles as building materials for different countries

    International Nuclear Information System (INIS)

    Ortiz, Josefina; Ballesteros, Luisa; Serradell, Vicente

    2008-01-01

    Measurements campaigns of ceramic tiles and raw materials used in them, shows that natural radionuclides of uranium ( 238 U) and thorium ( 232 Th) series, together with the radioactive isotope of potassium ( 40 K ), are presents. Uranium series contain radium, which decays to radon ( 222 Rn), an inert gas that can be released from materials and inhaled by individuals. Limits of 226 Ra concentrations are established by different countries in order to control Radon levels (200 Bq.m -3 in European Union). Potassium -40 and others gamma emitters of 226 Ra and 232 Th descendent, can cause an external dose. Therefore, with the purpose that individual doses due to building materials doesn't exceed a certain level recommendations or regulations have been established. A maximum value of 1 mSv.y -1 is recommended in European Union. In practice an easy way to avoid ceramic tiles provide doses to individuals over the reference level is to introduce an index, depending on activities concentrations of 226 Ra, 232 Th and 40 K, defined so that the dose limits due, exclusively, to building materials, will never be exceeded. These limits and indexes present differences between countries. In this paper indexes are compared and differences are discussed. (author)

  15. Goeckerman's therapy for psoriasis with special reference to serum pentraxin 3 level

    Energy Technology Data Exchange (ETDEWEB)

    Ctirad, A.; Lenka, B.; David, P.; Zdenek, F.; Kveta, H.; Karel, E.; Jan, K. [Charles University Prague, Hradec Kralove (Czech Republic). University Hospital

    2008-10-15

    Goeckerman's therapy (GT) of psoriasis is based on daily application of pharmacy grade coal tar on affected skin with subsequent exposure to UV light. Pentraxin 3 (PTX3) is a newly identified acute phase reactant with non redundant functions in innate immunity. PTX3 has been shown to be a reliable prognostic marker in patients with various inflammatory disorders including rheumatoid arthritis, vasculitis, and psoriasis. The aim of this study was to evaluate the influence of Goeckerman's therapy of psoriasis on levels of two pentraxins: long pentraxin PTX3 and C reactive protein in 49 patients with chronic plaque psoriasis. CRP was assessed by immunonephelometry on IMMAGE 800 (Beckman, USA). PTX3 was detected using sandwich ELISA detection set (Alexis Biochemicals, Switzerland). The serum levels of both parameters (expressed as average {+-} 1 SD) were significantly diminished after GT. The level of PTX3 dropped from 1.92 {+-} 0.72 ng/ml before GT to 1.66 {+-} 0.58 ng/ml after GT (P = 0.0396) and the level of CRP fell from 4.64 {+-} 3.93 mg/l to 1.66 {+-} 0.58 mg/l (P {lt} 0.0001). Comparing to healthy controls, the serum levels of both parameters before GT were significantly higher than those found in healthy blood donors and remained significantly increased after GT. Increased serum concentrations of pentraxin 3 and CRP are alleviated by GT in patients with psoriasis.

  16. A simple mass-conserved level set method for simulation of multiphase flows

    Science.gov (United States)

    Yuan, H.-Z.; Shu, C.; Wang, Y.; Shu, S.

    2018-04-01

    In this paper, a modified level set method is proposed for simulation of multiphase flows with large density ratio and high Reynolds number. The present method simply introduces a source or sink term into the level set equation to compensate the mass loss or offset the mass increase. The source or sink term is derived analytically by applying the mass conservation principle with the level set equation and the continuity equation of flow field. Since only a source term is introduced, the application of the present method is as simple as the original level set method, but it can guarantee the overall mass conservation. To validate the present method, the vortex flow problem is first considered. The simulation results are compared with those from the original level set method, which demonstrates that the modified level set method has the capability of accurately capturing the interface and keeping the mass conservation. Then, the proposed method is further validated by simulating the Laplace law, the merging of two bubbles, a bubble rising with high density ratio, and Rayleigh-Taylor instability with high Reynolds number. Numerical results show that the mass is a well-conserved by the present method.

  17. Mapping topographic structure in white matter pathways with level set trees.

    Directory of Open Access Journals (Sweden)

    Brian P Kent

    Full Text Available Fiber tractography on diffusion imaging data offers rich potential for describing white matter pathways in the human brain, but characterizing the spatial organization in these large and complex data sets remains a challenge. We show that level set trees--which provide a concise representation of the hierarchical mode structure of probability density functions--offer a statistically-principled framework for visualizing and analyzing topography in fiber streamlines. Using diffusion spectrum imaging data collected on neurologically healthy controls (N = 30, we mapped white matter pathways from the cortex into the striatum using a deterministic tractography algorithm that estimates fiber bundles as dimensionless streamlines. Level set trees were used for interactive exploration of patterns in the endpoint distributions of the mapped fiber pathways and an efficient segmentation of the pathways that had empirical accuracy comparable to standard nonparametric clustering techniques. We show that level set trees can also be generalized to model pseudo-density functions in order to analyze a broader array of data types, including entire fiber streamlines. Finally, resampling methods show the reliability of the level set tree as a descriptive measure of topographic structure, illustrating its potential as a statistical descriptor in brain imaging analysis. These results highlight the broad applicability of level set trees for visualizing and analyzing high-dimensional data like fiber tractography output.

  18. Developing patient-specific dose protocols for a CT scanner and exam using diagnostic reference levels

    International Nuclear Information System (INIS)

    Strauss, Keith J.

    2014-01-01

    The management of image quality and radiation dose during pediatric CT scanning is dependent on how well one manages the radiographic techniques as a function of the type of exam, type of CT scanner, and patient size. The CT scanner's display of expected CT dose index volume (CTDI vol ) after the projection scan provides the operator with a powerful tool prior to the patient scan to identify and manage appropriate CT techniques, provided the department has established appropriate diagnostic reference levels (DRLs). This paper provides a step-by-step process that allows the development of DRLs as a function of type of exam, of actual patient size and of the individual radiation output of each CT scanner in a department. Abdomen, pelvis, thorax and head scans are addressed. Patient sizes from newborns to large adults are discussed. The method addresses every CT scanner regardless of vendor, model or vintage. We cover adjustments to techniques to manage the impact of iterative reconstruction and provide a method to handle all available voltages other than 120 kV. This level of management of CT techniques is necessary to properly monitor radiation dose and image quality during pediatric CT scans. (orig.)

  19. 76 FR 9004 - Public Comment on Setting Achievement Levels in Writing

    Science.gov (United States)

    2011-02-16

    ... DEPARTMENT OF EDUCATION Public Comment on Setting Achievement Levels in Writing AGENCY: U.S... Achievement Levels in Writing. SUMMARY: The National Assessment Governing Board (Governing Board) is... for NAEP in writing. This notice provides opportunity for public comment and submitting...

  20. Application of physiologically based pharmacokinetic modeling in setting acute exposure guideline levels for methylene chloride.

    NARCIS (Netherlands)

    Bos, Peter Martinus Jozef; Zeilmaker, Marco Jacob; Eijkeren, Jan Cornelis Henri van

    2006-01-01

    Acute exposure guideline levels (AEGLs) are derived to protect the human population from adverse health effects in case of single exposure due to an accidental release of chemicals into the atmosphere. AEGLs are set at three different levels of increasing toxicity for exposure durations ranging from

  1. A study to establish international diagnostic reference levels for paediatric computed tomography

    International Nuclear Information System (INIS)

    Vassileva, J.; Rehani, M.; Kostova-Lefterova, D.; Al-Naemi, H.M.; Al Suwaidi, J.S.; Arandjic, D.; Bashier, E.H.O.; Kodlulovich Renha, S.; El-Nachef, L.; Aguilar, J.G.; Gershan, V.; Gershkevitsh, E.; Gruppetta, E.; Hustuc, A.; Jauhari, A.; Hassan Kharita, Mohammad; Khelassi-Toutaoui, N.; Khosravi, H.R.; Khoury, H.; Kralik, I.; Mahere, S.; Mazuoliene, J.; Mora, P.; Muhogora, W.; Muthuvelu, P.; Nikodemova, D.; Novak, L.; Pallewatte, A.; Pekarovic, D.; Shaaban, M.; Shelly, E.; Stepanyan, K.; Thelsy, N.; Visrutaratna, P.; Zaman, A.

    2015-01-01

    The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol ) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDI w , CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75. percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided. (authors)

  2. Diagnostic Reference Levels for Patient Radiation Doses in Pelvis and Lumbar spine Radiography in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Yong; Lee, Byung Young; Lee, Jung Eun; Lee, Hyun Koo; Jung, Seunbg Hwan; Kim, Byung Woo; Kim, Hyeog Ju; Kim, Dong Sup [Radiation Safety Division National Institute of Food and Drug Safety Evaluation, Seoul (Korea, Republic of)

    2009-12-15

    Pelvis and lumbar spine radiography, among various types of diagnostic radiography, include gonads of the human body and give patients high radiation dose. Nevertheless, diagnostic reference levels for patient radiation dose in pelvis and lumbar spine radiography has not yet been established in Korea. Therefore, the radiation dose that patients receive from pelvis and lumbar radiography is measured and the diagnostic reference level on patient radiation dose for the optimization of radiation protection of patients in pelvis and lumbar spine radiography was established. The conditions and diagnostic imaging information acquired during the time of the postero-anterior view of the pelvis and the postero-anterior and lateral view of the lumbar spine at 125 medical institutions throughout Korea are collected for analysis and the entrance surface dose received by patients is measured using a glass dosimeter. The diagnostic reference levels for patient radiation dose in pelvis and lumbar spine radiography to be recommended to the medical institutes is arranged by establishing the dose from the patient radiation dose that corresponds to the 3rd quartile values as the appropriate diagnostic reference level for patient radiation dose. According to the results of the assessment of diagnostic imaging information acquired from pelvis and lumbar spine radiography and the measurement of patient entrance surface dose taken at the 125 medical institutes throughout Korea, the tube voltage ranged between 60-97 kVp, with the average use being 75 kVp, and the tube current ranged between 8-123 mAs, with the average use being 30 mAs. In the posteroanterior and lateral views of lumbar spine radiography, the tube voltage of each view ranged between 65-100 kVp (average use: 78 kVp) and 70-109 kVp (average use: 87 kVp), respectively, and the tube current of each view ranged between 10-100 mAs(average use: 35 mAs) and between 8.9-300 mAs(average use: 64 mAs), respectively. The measurements of

  3. Diagnostic Reference Levels for Patient Radiation Doses in Pelvis and Lumbar spine Radiography in Korea

    International Nuclear Information System (INIS)

    Lee, Kwang Yong; Lee, Byung Young; Lee, Jung Eun; Lee, Hyun Koo; Jung, Seunbg Hwan; Kim, Byung Woo; Kim, Hyeog Ju; Kim, Dong Sup

    2009-01-01

    Pelvis and lumbar spine radiography, among various types of diagnostic radiography, include gonads of the human body and give patients high radiation dose. Nevertheless, diagnostic reference levels for patient radiation dose in pelvis and lumbar spine radiography has not yet been established in Korea. Therefore, the radiation dose that patients receive from pelvis and lumbar radiography is measured and the diagnostic reference level on patient radiation dose for the optimization of radiation protection of patients in pelvis and lumbar spine radiography was established. The conditions and diagnostic imaging information acquired during the time of the postero-anterior view of the pelvis and the postero-anterior and lateral view of the lumbar spine at 125 medical institutions throughout Korea are collected for analysis and the entrance surface dose received by patients is measured using a glass dosimeter. The diagnostic reference levels for patient radiation dose in pelvis and lumbar spine radiography to be recommended to the medical institutes is arranged by establishing the dose from the patient radiation dose that corresponds to the 3rd quartile values as the appropriate diagnostic reference level for patient radiation dose. According to the results of the assessment of diagnostic imaging information acquired from pelvis and lumbar spine radiography and the measurement of patient entrance surface dose taken at the 125 medical institutes throughout Korea, the tube voltage ranged between 60-97 kVp, with the average use being 75 kVp, and the tube current ranged between 8-123 mAs, with the average use being 30 mAs. In the posteroanterior and lateral views of lumbar spine radiography, the tube voltage of each view ranged between 65-100 kVp (average use: 78 kVp) and 70-109 kVp (average use: 87 kVp), respectively, and the tube current of each view ranged between 10-100 mAs(average use: 35 mAs) and between 8.9-300 mAs(average use: 64 mAs), respectively. The measurements of

  4. SU-E-P-10: Establishment of Local Diagnostic Reference Levels of Routine Exam in Computed Tomography

    International Nuclear Information System (INIS)

    Yeh, M; Wang, Y; Weng, H

    2015-01-01

    Introduction National diagnostic reference levels (NDRLs) can be used as a reference dose of radiological examination can provide radiation dose as the basis of patient dose optimization. Local diagnostic reference levels (LDRLs) by periodically view and check doses, more efficiency to improve the way of examination. Therefore, the important first step is establishing a diagnostic reference level. Computed Tomography in Taiwan had been built up the radiation dose limit value,in addition, many studies report shows that CT scan contributed most of the radiation dose in different medical. Therefore, this study was mainly to let everyone understand DRL’s international status. For computed tomography in our hospital to establish diagnostic reference levels. Methods and Materials: There are two clinical CT scanners (a Toshiba Aquilion and a Siemens Sensation) were performed in this study. For CT examinations the basic recommended dosimetric quantity is the Computed Tomography Dose Index (CTDI). Each exam each different body part, we collect 10 patients at least. Carried out the routine examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined. Results: The majority of patients (75%) were between 60–70 Kg of body weight. There are 25 examinations in this study. Table 1 shows the LDRL of each CT routine examination. Conclusions: Therefore, this study would like to let everyone know DRL’s international status, but also establishment of computed tomography of the local reference levels for our hospital, and providing radiation reference, as a basis for optimizing patient dose

  5. SU-E-P-10: Establishment of Local Diagnostic Reference Levels of Routine Exam in Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, M; Wang, Y; Weng, H [Chiayi Chang Gung Memorial Hospital of The C.G.M.F, Puzi City, Chiayi County, Taiwan (China)

    2015-06-15

    Introduction National diagnostic reference levels (NDRLs) can be used as a reference dose of radiological examination can provide radiation dose as the basis of patient dose optimization. Local diagnostic reference levels (LDRLs) by periodically view and check doses, more efficiency to improve the way of examination. Therefore, the important first step is establishing a diagnostic reference level. Computed Tomography in Taiwan had been built up the radiation dose limit value,in addition, many studies report shows that CT scan contributed most of the radiation dose in different medical. Therefore, this study was mainly to let everyone understand DRL’s international status. For computed tomography in our hospital to establish diagnostic reference levels. Methods and Materials: There are two clinical CT scanners (a Toshiba Aquilion and a Siemens Sensation) were performed in this study. For CT examinations the basic recommended dosimetric quantity is the Computed Tomography Dose Index (CTDI). Each exam each different body part, we collect 10 patients at least. Carried out the routine examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined. Results: The majority of patients (75%) were between 60–70 Kg of body weight. There are 25 examinations in this study. Table 1 shows the LDRL of each CT routine examination. Conclusions: Therefore, this study would like to let everyone know DRL’s international status, but also establishment of computed tomography of the local reference levels for our hospital, and providing radiation reference, as a basis for optimizing patient dose.

  6. Carcinogenesis and low-level ionizing radiation with special reference to lung cancer and exposure to radon daughters

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J.I.

    1982-04-01

    Of the important health effects of ionizing radiation, three important late effects - carcinogenesis, teratogenesis and mutagenesis are of greatest concern. This is because any exposure, even at low levels, carries some risk of such deleterious effects. As the dose of radiation increases above very low levels, the risk of health effects increases. Cancer-induction is the most important late somatic effect of low-dose ionizing radiation. Solid cancers, rather than leukemia, are principal late effects in exposed individuals. Tissues vary greatly in their susceptibility to radiation carcinogenesis. The most frequently occurring radiation-induced cancers in man include, in decreasing order of susceptibility: the female breast, the thyroid gland, the blood-forming tissues, the lung, certain organs of the gastrointestinal tract, and the bones. A number of biological and physical factors affect the cancer risk, such as age, sex, life-style, LET, and RBE. Despite uncertainty about low-level radiation risks, regulatory and advisory bodies must set standards for exposure, and individuals need information to be able to make informed judgments for themselves. From the point of view of the policy maker, the overriding concern is the fact that small doses of radiation can cause people to have more cancers than would otherwise be expected. While concern for all radiation effects exists, our human experience is limited to cancer-induction in exposed populations. This discussion is limited to cancer risk estimation and decision-making in relation to the health effects on populations of exposure to low levels of ionizing radiation. Here, low-level radiation will refer to yearly whole-body doses up to 5 rems or 0.05 Sv, or to cumulative doses up to 50 rems or 0.5 Sv from low-LET radiation and from high-LET radiation. (ERB)

  7. Carcinogenesis and low-level ionizing radiation with special reference to lung cancer and exposure to radon daughters

    International Nuclear Information System (INIS)

    Fabrikant, J.I.

    1982-04-01

    Of the important health effects of ionizing radiation, three important late effects - carcinogenesis, teratogenesis and mutagenesis are of greatest concern. This is because any exposure, even at low levels, carries some risk of such deleterious effects. As the dose of radiation increases above very low levels, the risk of health effects increases. Cancer-induction is the most important late somatic effect of low-dose ionizing radiation. Solid cancers, rather than leukemia, are principal late effects in exposed individuals. Tissues vary greatly in their susceptibility to radiation carcinogenesis. The most frequently occurring radiation-induced cancers in man include, in decreasing order of susceptibility: the female breast, the thyroid gland, the blood-forming tissues, the lung, certain organs of the gastrointestinal tract, and the bones. A number of biological and physical factors affect the cancer risk, such as age, sex, life-style, LET, and RBE. Despite uncertainty about low-level radiation risks, regulatory and advisory bodies must set standards for exposure, and individuals need information to be able to make informed judgments for themselves. From the point of view of the policy maker, the overriding concern is the fact that small doses of radiation can cause people to have more cancers than would otherwise be expected. While concern for all radiation effects exists, our human experience is limited to cancer-induction in exposed populations. This discussion is limited to cancer risk estimation and decision-making in relation to the health effects on populations of exposure to low levels of ionizing radiation. Here, low-level radiation will refer to yearly whole-body doses up to 5 rems or 0.05 Sv, or to cumulative doses up to 50 rems or 0.5 Sv from low-LET radiation and from high-LET radiation

  8. Exploring different forest definitions and their impact on developing REDD+ reference emission levels: A case study for Indonesia

    NARCIS (Netherlands)

    Romijn, J.E.; Ainembabazi, J.H.; Wijaya, A.; Herold, M.; Angelsen, A.; Verchot, L.; Murdiyarso, D.

    2013-01-01

    Developing countries participating in the mitigation mechanism of reducing emissions from deforestation and forest degradation and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks (REDD+), need to determine a national forest reference emission level

  9. Variational Level Set Method for Two-Stage Image Segmentation Based on Morphological Gradients

    Directory of Open Access Journals (Sweden)

    Zemin Ren

    2014-01-01

    Full Text Available We use variational level set method and transition region extraction techniques to achieve image segmentation task. The proposed scheme is done by two steps. We first develop a novel algorithm to extract transition region based on the morphological gradient. After this, we integrate the transition region into a variational level set framework and develop a novel geometric active contour model, which include an external energy based on transition region and fractional order edge indicator function. The external energy is used to drive the zero level set toward the desired image features, such as object boundaries. Due to this external energy, the proposed model allows for more flexible initialization. The fractional order edge indicator function is incorporated into the length regularization term to diminish the influence of noise. Moreover, internal energy is added into the proposed model to penalize the deviation of the level set function from a signed distance function. The results evolution of the level set function is the gradient flow that minimizes the overall energy functional. The proposed model has been applied to both synthetic and real images with promising results.

  10. Appropriate criteria set for personnel promotion across organizational levels using analytic hierarchy process (AHP

    Directory of Open Access Journals (Sweden)

    Charles Noven Castillo

    2017-01-01

    Full Text Available Currently, there has been limited established specific set of criteria for personnel promotion to each level of the organization. This study is conducted in order to develop a personnel promotion strategy by identifying specific sets of criteria for each level of the organization. The complexity of identifying the criteria set along with the subjectivity of these criteria require the use of multi-criteria decision-making approach particularly the analytic hierarchy process (AHP. Results show different sets of criteria for each management level which are consistent with several frameworks in literature. These criteria sets would help avoid mismatch of employee skills and competencies and their job, and at the same time eliminate the issues in personnel promotion such as favouritism, glass ceiling, and gender and physical attractiveness preference. This work also shows that personality and traits, job satisfaction and experience and skills are more critical rather than social capital across different organizational levels. The contribution of this work is in identifying relevant criteria in developing a personnel promotion strategy across organizational levels.

  11. The role and impact of reference doses on diagnostic radiology, how to use them at the national level?

    International Nuclear Information System (INIS)

    Nikodemova, D.; Horvathova, M.; Karkus, R.

    2003-01-01

    Results of patient dose audits reported in this paper for several types of examinations and various technical units have shown the importance of applications of reference dose levels in radiological practice. On the basis of national surveys slightly lower or higher standard dose reference levels (DRL) values could be justified. Continuing revision of DRL values and their extension to other types of radiographic and fluoroscopic examinations is needed

  12. Introducing carrying capacity-based normalisation in LCA: framework and development of references at midpoint level

    DEFF Research Database (Denmark)

    Bjørn, Anders; Hauschild, Michael Zwicky

    2015-01-01

    carrying capacity-based normalisation references. The purpose of this article is to present a framework for normalisation against carrying capacity-based references and to develop average normalisation references (NR) for Europe and the world for all those midpoint impact categories commonly included....... A literature review was carried out to identify scientifically sound thresholds for each impact category. Carrying capacities were then calculated from these thresholds and expressed in metrics identical to midpoint indicators giving priority to those recommended by ILCD. NR was expressed as the carrying...... ozone formation and soil quality were found to exceed carrying capacities several times.The developed carrying capacity-based normalisation references offer relevant supplementary reference information to the currently applied references based on society’s background interventions by supporting...

  13. Characteristics of the Remote Sensing Data Used in the Proposed Unfccc REDD+ Forest Reference Emission Levels (frels)

    Science.gov (United States)

    Johnson, B. A.; Scheyvens, H.; Samejima, H.; Onoda, M.

    2016-06-01

    Developing countries must submit forest reference emission levels (FRELs) to the UNFCCC to receive incentives for REDD+ activities (e.g. reducing emissions from deforestation/forest degradation, sustainable management of forests, forest carbon stock conservation/enhancement). These FRELs are generated based on historical CO2 emissions in the land use, land use change, and forestry sector, and are derived using remote sensing (RS) data and in-situ forest carbon measurements. Since the quality of the historical emissions estimates is affected by the quality and quantity of the RS data used, in this study we calculated five metrics (i-v below) to assess the quality and quantity of the data that has been used thus far. Countries could focus on improving on one or more of these metrics for the submission of future FRELs. Some of our main findings were: (i) the median percentage of each country mapped was 100%, (ii) the median historical timeframe for which RS data was used was 11.5 years, (iii) the median interval of forest map updates was 4.5 years, (iv) the median spatial resolution of the RS data was 30m, and (v) the median number of REDD+ activities that RS data was used for operational monitoring of was 1 (typically deforestation). Many new sources of RS data have become available in recent years, so complementary or alternative RS data sets for generating future FRELs can potentially be identified based on our findings; e.g. alternative RS data sets could be considered if they have similar or higher quality/quantity than the currently-used data sets.

  14. Priority setting at the micro-, meso- and macro-levels in Canada, Norway and Uganda.

    Science.gov (United States)

    Kapiriri, Lydia; Norheim, Ole Frithjof; Martin, Douglas K

    2007-06-01

    The objectives of this study were (1) to describe the process of healthcare priority setting in Ontario-Canada, Norway and Uganda at the three levels of decision-making; (2) to evaluate the description using the framework for fair priority setting, accountability for reasonableness; so as to identify lessons of good practices. We carried out case studies involving key informant interviews, with 184 health practitioners and health planners from the macro-level, meso-level and micro-level from Canada-Ontario, Norway and Uganda (selected by virtue of their varying experiences in priority setting). Interviews were audio-recorded, transcribed and analyzed using a modified thematic approach. The descriptions were evaluated against the four conditions of "accountability for reasonableness", relevance, publicity, revisions and enforcement. Areas of adherence to these conditions were identified as lessons of good practices; areas of non-adherence were identified as opportunities for improvement. (i) at the macro-level, in all three countries, cabinet makes most of the macro-level resource allocation decisions and they are influenced by politics, public pressure, and advocacy. Decisions within the ministries of health are based on objective formulae and evidence. International priorities influenced decisions in Uganda. Some priority-setting reasons are publicized through circulars, printed documents and the Internet in Canada and Norway. At the meso-level, hospital priority-setting decisions were made by the hospital managers and were based on national priorities, guidelines, and evidence. Hospital departments that handle emergencies, such as surgery, were prioritized. Some of the reasons are available on the hospital intranet or presented at meetings. Micro-level practitioners considered medical and social worth criteria. These reasons are not publicized. Many practitioners lacked knowledge of the macro- and meso-level priority-setting processes. (ii) Evaluation

  15. Derivation of a reference dose and drinking water equivalent level for 1,2,3-trichloropropane.

    Science.gov (United States)

    Tardiff, Robert G; Carson, M Leigh

    2010-06-01

    In some US potable water supplies, 1,2,3-trichloropropane (TCP) has been present at ranges of non-detect to less than 100 ppb, resulting from past uses. In subchronic oral studies, TCP produced toxicity in kidneys, liver, and other tissues. TCP administered by corn oil gavage in chronic studies produced tumors at multiple sites in rats and mice; however, interpretation of these studies was impeded by substantial premature mortality. Drinking water equivalent levels (DWELs) were estimated for a lifetime of consumption by applying biologically-based safety/risk assessment approaches, including Monte Carlo techniques, and with consideration of kinetics and modes of action, to possibly replace default assumptions. Internationally recognized Frameworks for human relevance of animal data were employed to interpret the findings. Calculated were a reference dose (=39 microg/kg d) for non-cancer and Cancer Values (CV) (=10-14 microg/kg d) based on non-linear dose-response relationships for mutagenicity as a precursor of cancer. Lifetime Average Daily Intakes (LADI) are 3130 and 790-1120 microg/person-d for non-cancer and cancer, respectively. DWELs, estimated by applying a relative source contribution (RSC) of 50% to the LADIs, are 780 and 200-280 microg/L for non-cancer and cancer, respectively. These DWELs may inform establishment of formal/informal guidelines and standards to protect public health. Copyright 2010 Elsevier Ltd. All rights reserved.

  16. Towards the definition of Institutional diagnostic reference levels in paediatric interventional cardiology procedures in Greece.

    Science.gov (United States)

    Kottou, S; Kollaros, N; Plemmenos, C; Mastorakou, I; Apostolopoulou, S C; Tsapaki, V

    2018-02-01

    This study aimed to evaluate paediatric radiation doses in a dedicated cardiology hospital, with the objective of characterising patterns in dose variation. The ultimate purpose was to define Local (Institutional) Diagnostic Reference Levels (LDRLs) for different types of paediatric cardiac interventional procedures (IC), according to patient age. From a total of 710 cases performed during three consecutive years, by operators with more than 15 years of experience, the age was noted in only 477 IC procedures. The median values obtained for Fluoroscopy Time (FT), Number of Frames (N) and Kerma Area Product (P KA ) by age range were 5.8 min, 1322 and 2.0 Gy.cm 2 for definition of LDRLs presents challenges mainly due to the multiple clinical and technical factors affecting the outcome. On the other hand the lack of paediatric IC DRLs makes the identification of good practices more difficult. A consensus is needed on IC procedures nomenclature and grouping in order to allow a common assessment and comparison of doses. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Estimating the population dose from nuclear medicine examinations towards establishing diagnostic reference levels

    International Nuclear Information System (INIS)

    Niksirat, Fatemeh; Monfared, Ali Shabestani; Deevband, Mohammad Reza; Amiri, Mehrangiz; Gholami, Amir

    2016-01-01

    This study conducted a review on nuclear medicine (NM) services in Mazandaran Province with a view to establish adult diagnostic reference levels (DRLs) and provide updated data on population radiation exposure resulting from diagnostic NM procedures. The data were collected from all centers in all cities of Mazandaran Province in the North of Iran from March 2014 to February 2015. The 75 th percentile of the distribution and the average administered activity (AAA) were calculated and the average effective dose per examination, collective effective dose to the population and annual effective dose per capita were estimated using dose conversion factors. The gathered data were analyzed via SPSS (version 18) software using descriptive statistics. Based on the data of this study, the collective effective dose was 95.628 manSv, leading to a mean effective dose of 0.03 mSv per capita. It was also observed that the myocardial perfusion was the most common procedure (50%). The 75 th percentile of the distribution of administered activity (AA) represents the DRL. The AAA and the 75 th percentile of the distribution of AA are slightly higher than DRL of most European countries. Myocardial perfusion is responsible for most of the collective effective dose and it is better to establish national DRLs for myocardial perfusion and review some DRL values through the participation of NM specialists in the future

  18. Pregnancy and variations of carbohydrate-deficient transferrin levels measured by the candidate reference HPLC method.

    Science.gov (United States)

    Bianchi, Vincenza; Ivaldi, Alessandra; Raspagni, Alessia; Arfini, Carlo; Vidali, Matteo

    2011-01-01

    Contrasting data are available on the diagnostic accuracy of carbohydrate-deficient transferrin (CDT) during pregnancy. These differences may depend in part on how CDT was evaluated and expressed. Here, we report on variations of CDT levels in pregnant women using the high performance liquid chromatography (HPLC) candidate reference method. Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, mean corpuscular volume, serum transferrin, urine and serum ethyl glucuronide and CDT were measured in 64 women, self-reporting as non-alcohol abusers (age: median 34, IQR: 28-38), at different stages of normal pregnancy (gestational weeks: median 28, IQR: 8-33). CDT was expressed as percentage of disialotransferrin to total transferrin (%CDT). Transferrin was associated with both %CDT (r = 0.66; P pregnancy trimester (first trimester: mean 1.01% (SD 0.19); second trimester: 1.30% (SD 0.14); third trimester: 1.53% (SD 0.22); ANOVA P pregnancy trimesters (P pregnancy and CDT could be more complex. The diagnostic accuracy of CDT for detecting alcohol abuse in a legal context may be limited in pregnant women and the effect of gestational age should be considered.

  19. Dose area product measurement for diagnostic reference levels and analysis of patient dose in dental radiography

    International Nuclear Information System (INIS)

    Han, S.; Lee, B.; Shin, G.; Choi, J.; Kim, J.; Park, C.; Park, H.; Lee, K.; Kim, Y.

    2008-01-01

    In this study, diagnostic reference levels (DRLs) were suggested and patient doses were analysed through the dose-area product value in dental radiography. In intraoral radiography, at three sites, i.e. molar, premolar and incisor on the maxilla and acquired third quartile values: 55.5, 46 and 36.5 mGy cm 2 , respectively, were measured. In panoramic, cephalo-metric and cone beam computed tomography, the values were 120.3, 146 and 3203 mGy cm 2 (16 x 18 cm), respectively. It has been shown that, in intraoral radiography, the patient dose changes proportionally to the value of mA s, but the change in extra-oral radiography in response to mA s could not be confirmed. The authors could confirm, however, the difference in dose according to the manufacturer in all dental radiography examinations, except for panoramic radiography. Depending on the size of hospital, there were some differences in patient dose in intraoral radiography, but no difference in patient dose in extra-oral radiography. (authors)

  20. Radiation safety concerns and diagnostic reference levels for computed tomography scanners in Tamil Nadu

    International Nuclear Information System (INIS)

    Livingstone, Roshan S.; Dinakaran, Paul M.

    2011-01-01

    Radiation safety in computed tomography (CT) scanners is of concern due its widespread use in the field of radiological imaging. This study intends to evaluate radiation doses imparted to patients undergoing thorax, abdomen and pelvic CT examinations and formulate regional diagnostic reference levels (DRL) in Tamil Nadu, South India. In-site CT dose measurement was performed in 127 CT scanners in Tamil Nadu for a period of 2 years as a part of the Atomic Energy Regulatory Board (AERB)-funded project. Out of the 127 CT scanners,13 were conventional; 53 single-slice helical scanners (SSHS); 44 multislice CT (MSCT) scanners; and 17 refurbished scanners. CT dose index (CTDI) was measured using a 32-cm polymethyl methacrylate (PMMA)-body phantom in each CT scanner. Dose length product (DLP) for different anatomical regions was generated using CTDI values. The regional DRLs for thorax, abdomen and pelvis examinations were 557, 521 and 294 mGy cm, respectively. The mean effective dose was estimated using the DLP values and was found to be 8.04, 6.69 and 4.79 mSv for thorax, abdomen and pelvic CT examinations, respectively. The establishment of DRLs in this study is the first step towards optimization of CT doses in the Indian context. (author)

  1. Patient doses in CT examinations in Switzerland: Implementation of national diagnostic reference levels

    International Nuclear Information System (INIS)

    Treier, R.; Aroua, A.; Verdun, F. R.; Samara, E.; Stuessi, A.; Trueb, P. R.

    2010-01-01

    Diagnostic reference levels (DRLs) were established for 21 indication-based CT examinations for adults in Switzerland. One hundred and seventy-nine of 225 computed tomography (CT) scanners operated in hospitals and private radiology institutes were audited on-site and patient doses were collected. For each CT scanner, a correction factor was calculated expressing the deviation of the measured weighted computed tomography dose index (CTDI) to the nominal weighted CTDI as displayed on the workstation. Patient doses were corrected by this factor providing a realistic basis for establishing national DRLs. Results showed large variations in doses between different radiology departments in Switzerland, especially for examinations of the petrous bone, pelvis, lower limbs and heart. This indicates that the concept of DRLs has not yet been correctly applied for CT examinations in clinical routine. A close collaboration of all stakeholders is mandatory to assure an effective radiation protection of patients. On-site audits will be intensified to further establish the concept of DRLs in Switzerland. (authors)

  2. Establishment of computed tomography reference dose levels in Onassis Cardiac Surgery Center

    International Nuclear Information System (INIS)

    Tsapaki, V.; Kyrozi, E.; Syrigou, T.; Mastorakou, I.; Kottou, S.

    2001-01-01

    The purpose of the study was to apply European Commission (EC) Reference Dose Levels (RDL) in Computed Tomography (CT) examinations at Onassis Cardiac Surgery Center (OCSC). These are weighted CT Dose Index (CTDI w ) for a single slice and Dose-Length Product (DLP) for a complete examination. During the period 1998-1999, the total number of CT examinations, every type of CT examination, patient related data and technical parameters of the examinations were recorded. The most frequent examinations were chosen for investigation which were the head, chest, abdomen and pelvis. CTDI measurements were performed and CTDI w and DLP were calculated. Third Quartile values of CTDI w were chosen to be 43mGy for head, 8mGy for chest, and 22mGy for abdomen and pelvis examinations. Third quartile values of DLP were chosen to be 740mGycm for head, 370mGycm for chest, 490mGycm for abdomen and 420mGycm for pelvis examination. Results confirm that OCSC follows successfully the proposed RDL for the head, chest, abdomen and pelvis examinations in terms of radiation dose. (author)

  3. 1-GWh diurnal load-leveling Superconducting Magnetic Energy Storage system reference design

    International Nuclear Information System (INIS)

    Rogers, J.D.; Hassenzahl, W.V.; Schermer, R.I.

    1979-09-01

    A point reference design has been completed for a 1-GWh Superconducting Magnetic Energy Storage system. The system is for electric utility diurnal load-leveling but can also function to meet much faster power demands including dynamic stabilization. This study explores several concepts of design not previously considered in the same detail as treated here. Because the study is for a point design, optimization in all respects is not complete. This report examines aspects of the coil, the superconductor supported off of the dewar shell, the dewar shell, and its configuration and stresses, the underground excavation and construction for holding the superconducting coil and its dewar, the helium refrigeration system, the electrical converter system, the vacuum system, the guard coil, and the costs. This report is divided into two major portions. The first is a general treatment of the work and the second is seven detailed technical appendices issued as separate reports. The information presented on the aluminum stabilizer for the conductor, on the excavation, and on the converter is based upon industrial studies contracted for this work

  4. Reactor Emergency Action Level Monitor: Volume 2, REALM user's reference guide: Final report

    International Nuclear Information System (INIS)

    Touchton, R.A.

    1988-09-01

    A User Manual for the Reactor Emergency Action Level Monitor (REALM) expert system prototype is provided in this volume. REALM has been designed to provide expert assistance in the identification of a nuclear power plant emergency situation and the determination of its severity. REALM has been developed as an expert system which can provide sensor interpretation and situation assessment in a real-time processing environment. In its state of development at project completion, these capabilities are used in an off-line (i.e., stand-alone, desktop) fashion to provide emergency preparedness assistance in the areas of emergency classification training and emergency exercise scenario generation. REALM also serves a prototype and stepping-stone for the possible connection to the plant for on-line use. In order to distinguish the off-line system (now complete) from the on-line system (now moving from a research prototype to an installed system), the term ''REALM'' is used to indicate the on-line version, with users in the control room, technical support center, and the emergency operations facility, The off-line version is referred to as ''uREALM.''

  5. The impact of diagnostic reference levels on patient doses from X-ray examinations

    International Nuclear Information System (INIS)

    Leitz, W.; Almen, A.

    2008-01-01

    The aim of this study was to evaluate the effect of diagnostic reference levels (DRL). For this study patient doses for the years 1999 and 2006 were available. Patient doses on a national level for eleven specified X-ray examinations were assessed. For the conventional examinations DRL have been used after the first survey in 1999, for computed tomography no DRL were used and for mammography DRL have been used for more than 20 years. Whereas the patient doses for conventional examinations were 30% lower in 2006 compared to 1999 the doses remained essentially the same for computed tomography and mammography. The widths of the dose distributions had only slightly decreased for conventional examinations and remained the same for computed tomography and mammography. This study has shown that after implementation of DRL a considerable dose reduction can be expected. Practices exceeding DRL will perform remedial actions with the aim to reduce dose, as demonstrated for the conventional examinations. Despite the fact that practices for computed tomography could compare doses with others practices, in the absence of DRL no actions to reduce doses were performed. The margin for further dose reductions in mammography is small due to the long term use of DRL. The impact of DRL on patient doses is changing with time. When introduced large dose reductions can be expected. After long term use DRL will counteract the introduction of new technique with unjustified high patient doses. Despite the merits in terms of dose saving it must be recognized that DRL has its limits - it has to be amended with other radiological protection activities. Other means and measures have to be developed, for example by the authorities, in order to ensure that optimisation is continued even when the patient doses are below the DRL. (author)

  6. Reconstruction of thin electromagnetic inclusions by a level-set method

    International Nuclear Information System (INIS)

    Park, Won-Kwang; Lesselier, Dominique

    2009-01-01

    In this contribution, we consider a technique of electromagnetic imaging (at a single, non-zero frequency) which uses the level-set evolution method for reconstructing a thin inclusion (possibly made of disconnected parts) with either dielectric or magnetic contrast with respect to the embedding homogeneous medium. Emphasis is on the proof of the concept, the scattering problem at hand being so far based on a two-dimensional scalar model. To do so, two level-set functions are employed; the first one describes location and shape, and the other one describes connectivity and length. Speeds of evolution of the level-set functions are calculated via the introduction of Fréchet derivatives of a least-square cost functional. Several numerical experiments on noiseless and noisy data as well illustrate how the proposed method behaves

  7. Aerostructural Level Set Topology Optimization for a Common Research Model Wing

    Science.gov (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia

    2014-01-01

    The purpose of this work is to use level set topology optimization to improve the design of a representative wing box structure for the NASA common research model. The objective is to minimize the total compliance of the structure under aerodynamic and body force loading, where the aerodynamic loading is coupled to the structural deformation. A taxi bump case was also considered, where only body force loads were applied. The trim condition that aerodynamic lift must balance the total weight of the aircraft is enforced by allowing the root angle of attack to change. The level set optimization method is implemented on an unstructured three-dimensional grid, so that the method can optimize a wing box with arbitrary geometry. Fast matching and upwind schemes are developed for an unstructured grid, which make the level set method robust and efficient. The adjoint method is used to obtain the coupled shape sensitivities required to perform aerostructural optimization of the wing box structure.

  8. Multi person detection and tracking based on hierarchical level-set method

    Science.gov (United States)

    Khraief, Chadia; Benzarti, Faouzi; Amiri, Hamid

    2018-04-01

    In this paper, we propose an efficient unsupervised method for mutli-person tracking based on hierarchical level-set approach. The proposed method uses both edge and region information in order to effectively detect objects. The persons are tracked on each frame of the sequence by minimizing an energy functional that combines color, texture and shape information. These features are enrolled in covariance matrix as region descriptor. The present method is fully automated without the need to manually specify the initial contour of Level-set. It is based on combined person detection and background subtraction methods. The edge-based is employed to maintain a stable evolution, guide the segmentation towards apparent boundaries and inhibit regions fusion. The computational cost of level-set is reduced by using narrow band technique. Many experimental results are performed on challenging video sequences and show the effectiveness of the proposed method.

  9. Level set methods for detonation shock dynamics using high-order finite elements

    Energy Technology Data Exchange (ETDEWEB)

    Dobrev, V. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Grogan, F. C. [Univ. of California, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kolev, T. V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rieben, R [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tomov, V. Z. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-26

    Level set methods are a popular approach to modeling evolving interfaces. We present a level set ad- vection solver in two and three dimensions using the discontinuous Galerkin method with high-order nite elements. During evolution, the level set function is reinitialized to a signed distance function to maintain ac- curacy. Our approach leads to stable front propagation and convergence on high-order, curved, unstructured meshes. The ability of the solver to implicitly track moving fronts lends itself to a number of applications; in particular, we highlight applications to high-explosive (HE) burn and detonation shock dynamics (DSD). We provide results for two- and three-dimensional benchmark problems as well as applications to DSD.

  10. A parametric level-set approach for topology optimization of flow domains

    DEFF Research Database (Denmark)

    Pingen, Georg; Waidmann, Matthias; Evgrafov, Anton

    2010-01-01

    of the design variables in the traditional approaches is seen as a possible cause for the slow convergence. Non-smooth material distributions are suspected to trigger premature onset of instationary flows which cannot be treated by steady-state flow models. In the present work, we study whether the convergence...... and the versatility of topology optimization methods for fluidic systems can be improved by employing a parametric level-set description. In general, level-set methods allow controlling the smoothness of boundaries, yield a non-local influence of design variables, and decouple the material description from the flow...... field discretization. The parametric level-set method used in this study utilizes a material distribution approach to represent flow boundaries, resulting in a non-trivial mapping between design variables and local material properties. Using a hydrodynamic lattice Boltzmann method, we study...

  11. Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values.

    Science.gov (United States)

    Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

    2014-10-01

    Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight-normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. © 2014 The Authors

  12. Setting-level influences on implementation of the responsive classroom approach.

    Science.gov (United States)

    Wanless, Shannon B; Patton, Christine L; Rimm-Kaufman, Sara E; Deutsch, Nancy L

    2013-02-01

    We used mixed methods to examine the association between setting-level factors and observed implementation of a social and emotional learning intervention (Responsive Classroom® approach; RC). In study 1 (N = 33 3rd grade teachers after the first year of RC implementation), we identified relevant setting-level factors and uncovered the mechanisms through which they related to implementation. In study 2 (N = 50 4th grade teachers after the second year of RC implementation), we validated our most salient Study 1 finding across multiple informants. Findings suggested that teachers perceived setting-level factors, particularly principal buy-in to the intervention and individualized coaching, as influential to their degree of implementation. Further, we found that intervention coaches' perspectives of principal buy-in were more related to implementation than principals' or teachers' perspectives. Findings extend the application of setting theory to the field of implementation science and suggest that interventionists may want to consider particular accounts of school setting factors before determining the likelihood of schools achieving high levels of implementation.

  13. Robust boundary detection of left ventricles on ultrasound images using ASM-level set method.

    Science.gov (United States)

    Zhang, Yaonan; Gao, Yuan; Li, Hong; Teng, Yueyang; Kang, Yan

    2015-01-01

    Level set method has been widely used in medical image analysis, but it has difficulties when being used in the segmentation of left ventricular (LV) boundaries on echocardiography images because the boundaries are not very distinguish, and the signal-to-noise ratio of echocardiography images is not very high. In this paper, we introduce the Active Shape Model (ASM) into the traditional level set method to enforce shape constraints. It improves the accuracy of boundary detection and makes the evolution more efficient. The experiments conducted on the real cardiac ultrasound image sequences show a positive and promising result.

  14. Individual-and Setting-Level Correlates of Secondary Traumatic Stress in Rape Crisis Center Staff.

    Science.gov (United States)

    Dworkin, Emily R; Sorell, Nicole R; Allen, Nicole E

    2016-02-01

    Secondary traumatic stress (STS) is an issue of significant concern among providers who work with survivors of sexual assault. Although STS has been studied in relation to individual-level characteristics of a variety of types of trauma responders, less research has focused specifically on rape crisis centers as environments that might convey risk or protection from STS, and no research to knowledge has modeled setting-level variation in correlates of STS. The current study uses a sample of 164 staff members representing 40 rape crisis centers across a single Midwestern state to investigate the staff member-and agency-level correlates of STS. Results suggest that correlates exist at both levels of analysis. Younger age and greater severity of sexual assault history were statistically significant individual-level predictors of increased STS. Greater frequency of supervision was more strongly related to secondary stress for non-advocates than for advocates. At the setting level, lower levels of supervision and higher client loads agency-wide accounted for unique variance in staff members' STS. These findings suggest that characteristics of both providers and their settings are important to consider when understanding their STS. © The Author(s) 2014.

  15. A Variational Level Set Model Combined with FCMS for Image Clustering Segmentation

    Directory of Open Access Journals (Sweden)

    Liming Tang

    2014-01-01

    Full Text Available The fuzzy C means clustering algorithm with spatial constraint (FCMS is effective for image segmentation. However, it lacks essential smoothing constraints to the cluster boundaries and enough robustness to the noise. Samson et al. proposed a variational level set model for image clustering segmentation, which can get the smooth cluster boundaries and closed cluster regions due to the use of level set scheme. However it is very sensitive to the noise since it is actually a hard C means clustering model. In this paper, based on Samson’s work, we propose a new variational level set model combined with FCMS for image clustering segmentation. Compared with FCMS clustering, the proposed model can get smooth cluster boundaries and closed cluster regions due to the use of level set scheme. In addition, a block-based energy is incorporated into the energy functional, which enables the proposed model to be more robust to the noise than FCMS clustering and Samson’s model. Some experiments on the synthetic and real images are performed to assess the performance of the proposed model. Compared with some classical image segmentation models, the proposed model has a better performance for the images contaminated by different noise levels.

  16. Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values.

    Science.gov (United States)

    Ubeda, Carlos; Miranda, Patricia; Vano, Eliseo

    2015-02-01

    To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there may be large differences in child size. These DRLs were obtained at the largest pediatric hospital in Chile, with an active optimization program, and could be used by other hospitals in the Latin America region to compare their current patient dose values and determine whether corrective action is appropriate. © 2015 American Association of Physicists in Medicine.

  17. SU-E-I-33: Establishment of CT Diagnostic Reference Levels in Province Nova Scotia

    Energy Technology Data Exchange (ETDEWEB)

    Tonkopi, E; Abdolell, M; Duffy, S [Dalhousie University and Queen Elizabeth II Health Sciences Centre, Halifax, NS (Canada)

    2015-06-15

    Purpose: To evaluate patient radiation dose from the most frequently performed CT examinations and to establish provincial diagnostic reference levels (DRLs) as a tool for protocol optimization. Methods: The study investigated the following CT examinations: head, chest, abdomen/pelvis, and chest/abdomen/pelvis (CAP). Dose data, volume CT dose index (CTDIvol) and dose-length product (DLP), were collected from 15 CT scanners installed during 2004–2014 in 11 hospital sites of Nova Scotia. All scanners had dose modulation options and multislice capability (16–128 detector rows). The sample for each protocol included 15 average size patients (70±20 kg). Provincial DRLs were calculated as the 75th percentile of patient dose distributions. The differences in dose between hospitals were evaluated with a single factor ANOVA statistical test. Generalized linear modeling was used to determine the factors associated with higher radiation dose. A sample of 36 abdominal studies performed on three different scanners was blinded and randomized for an assessment by an experienced radiologist who graded the imaging quality of anatomic structures. Results: Data for 900 patients were collected. The DRLs were proposed using CTDIvol (mGy) and DLP (mGy*cm) values for CT head (67 and 1049, respectively), chest (12 and 393), abdomen/pelvis (16 and 717), and CAP (14 and 1034). These DRLs were lower than the published national data except for the head CTDIvol. The differences between the means of the dose distributions from each scanner were statistically significant (p<0.05) for all examinations. A very weak correlation was found between the dose and the scanner age or the number of slices with Pearson’s correlation coefficients of 0.011–0.315. The blinded analysis of image quality demonstrated no clinically significant difference except for the noise category. Conclusion: Provincial DRLs were established for typical CT examinations. The variations in dose between the hospitals

  18. Establishment of local diagnostic reference levels for quality control in intraoral radiography.

    Science.gov (United States)

    Izawa, Maki; Harata, Yasuo; Shiba, Noriyoshi; Koizumi, Nobuhide; Ozawa, Tomonori; Takahashi, Nobutoshi; Okumura, Yasuhiko

    2017-01-01

    To investigate the dosage and imaging conditions for patients undergoing intraoral radiography at Meikai University Hospital and establish assurance and quality control data. Tube voltage, exposure time, and air kinetic energy released per unit mass (air kerma) of three intraoral radiography units were measured. To calculate the patient entrance dose (PED) for each radiograph using Insight film, we extracted data for 1063 patients from their exposure records. The PED was compared with the diagnostic reference level (DRL) from the European Commission and the UK. The tube voltage of the three units was maintained at 60 ± 2 kV. Differences in exposure time were less than 1.7 % for all units. The air kerma rates were well maintained within a 4.2 % error. Based on the patient data, there were no significant differences in the mean exposure times for males and females for all anatomical sites. The mean PED ranged from 1.09 ± 0.31 mGy for the mandibular incisors to 2.42 ± 0.33 mGy for the maxillary molars. The mean PED at the mandibular molars using InSight film was 1.59 ± 0.20 mGy, being less than the recommended value based on the DRL for intraoral radiography in the UK. We concluded that radiographic conditions at the hospital have been properly maintained. This basic quality control data may assist other dental radiation facilities to reduce patient dosage.

  19. Diagnostic reference levels for X-ray investigations in pain management units in Belgium

    International Nuclear Information System (INIS)

    Lichtherte, S.; Le Polain de Waroux, B.

    2008-01-01

    X-rays are commonly used in pain treatment centres where infiltrative techniques are performed. Although X-rays are useful in increasing the precision of infiltrative techniques, their use puts patients and staff at risk of radiation exposure. As a result, medical staff now have to obtain a certificate of training on the use of X-rays before being allowed to use X-rays in practice. This analysis was based on 373 detailed registrations of procedure-related parameters in the six centres that participated in this study between January 2009 and July 2009. Examinations chosen for inclusion in this study were the most commonly performed fluoroscopic imaging-guided procedures in a pain management unit: epidural (cervical/lumbar), facet joint nerve blocks (cervical/lumbar) and trans-foraminal (cervical/lumbar). The sample size, the dose-area product (DAP) range for whole population, the mean and the third quartile DAP corrected for patient size (DAP corr ), the screening time range, the mean and the third quartile screening time are presented. The proposed DRLs for epidural, facet joint nerve blocks and trans-foraminal are 0.5, 2.5 and 3 Gy cm 2 for DAP values and 12, 60 and 50 s for screening times, respectively. In the absence of national diagnostic reference levels (DRLs) for pain management fluoroscopic procedures, these DAP and screening time values provide a possible way of establishing provisional DRLs for local use. The values for each examination type could be used as a baseline against which to monitor the effectiveness of dose reduction strategies as part of the optimisation process that is the goal of any quality control and patient dose monitoring system. (authors)

  20. Studies of the anatomical, physiological and metabolic characteristics of the Indian population for setting up a Reference Man

    International Nuclear Information System (INIS)

    Dang, H.S.; Jaiswal, D.D. Parameswaran, M.; Krishnamony, S.

    1998-01-01

    This paper presents Indian data on various human characteristics such as physical, anatomical, physiological and metabolic parameters. The knowledge of these parameters is required for dosimetric purposes and for developing, secondary radiation standards for occupational workers and the general public. The data reported are for the adult population, as well as for the younger population at the ages newborn, and 1, 5, 10 and 15 years. On the basis of the collection, collation and generation of the above data, the characteristics of the Reference Indian Man are proposed. The comparison of Indian data with that for ICRP Reference Man (representing the Caucasian population) shows that most of the physical, physiological and anatomical characteristics of the Indian population are smaller. The weights of a few smaller organs such as thyroid, testes, etc. are comparable and the daily intake of drinking water, the sweat rate and urine excretion rate etc. are higher than those for ICRP Reference man. (author)

  1. Analysis of Forensic Autopsy in 120 Cases of Medical Disputes Among Different Levels of Institutional Settings.

    Science.gov (United States)

    Yu, Lin-Sheng; Ye, Guang-Hua; Fan, Yan-Yan; Li, Xing-Biao; Feng, Xiang-Ping; Han, Jun-Ge; Lin, Ke-Zhi; Deng, Miao-Wu; Li, Feng

    2015-09-01

    Despite advances in medical science, the causes of death can sometimes only be determined by pathologists after a complete autopsy. Few studies have investigated the importance of forensic autopsy in medically disputed cases among different levels of institutional settings. Our study aimed to analyze forensic autopsy in 120 cases of medical disputes among five levels of institutional settings between 2001 and 2012 in Wenzhou, China. The results showed an overall concordance rate of 55%. Of the 39% of clinically missed diagnosis, cardiovascular pathology comprises 55.32%, while respiratory pathology accounts for the remaining 44. 68%. Factors that increase the likelihood of missed diagnoses were private clinics, community settings, and county hospitals. These results support that autopsy remains an important tool in establishing causes of death in medically disputed case, which may directly determine or exclude the fault of medical care and therefore in helping in resolving these cases. © 2015 American Academy of Forensic Sciences.

  2. An investigation of children's levels of inquiry in an informal science setting

    Science.gov (United States)

    Clark-Thomas, Beth Anne

    Elementary school students' understanding of both science content and processes are enhanced by the higher level thinking associated with inquiry-based science investigations. Informal science setting personnel, elementary school teachers, and curriculum specialists charged with designing inquiry-based investigations would be well served by an understanding of the varying influence of certain present factors upon the students' willingness and ability to delve into such higher level inquiries. This study examined young children's use of inquiry-based materials and factors which may influence the level of inquiry they engaged in during informal science activities. An informal science setting was selected as the context for the examination of student inquiry behaviors because of the rich inquiry-based environment present at the site and the benefits previously noted in the research regarding the impact of informal science settings upon the construction of knowledge in science. The study revealed several patterns of behavior among children when they are engaged in inquiry-based activities at informal science exhibits. These repeated behaviors varied in the children's apparent purposeful use of the materials at the exhibits. These levels of inquiry behavior were taxonomically defined as high/medium/low within this study utilizing a researcher-developed tool. Furthermore, in this study adult interventions, questions, or prompting were found to impact the level of inquiry engaged in by the children. This study revealed that higher levels of inquiry were preceded by task directed and physical feature prompts. Moreover, the levels of inquiry behaviors were haltered, even lowered, when preceded by a prompt that focused on a science content or concept question. Results of this study have implications for the enhancement of inquiry-based science activities in elementary schools as well as in informal science settings. These findings have significance for all science educators

  3. Education level inequalities and transportation injury mortality in the middle aged and elderly in European settings

    NARCIS (Netherlands)

    Borrell, C.; Plasència, A.; Huisman, M.; Costa, G.; Kunst, A.; Andersen, O.; Bopp, M.; Borgan, J.-K.; Deboosere, P.; Glickman, M.; Gadeyne, S.; Minder, C.; Regidor, E.; Spadea, T.; Valkonen, T.; Mackenbach, J. P.

    2005-01-01

    OBJECTIVE: To study the differential distribution of transportation injury mortality by educational level in nine European settings, among people older than 30 years, during the 1990s. METHODS: Deaths of men and women older than 30 years from transportation injuries were studied. Rate differences

  4. A thick level set interface model for simulating fatigue-drive delamination in composites

    NARCIS (Netherlands)

    Latifi, M.; Van der Meer, F.P.; Sluys, L.J.

    2015-01-01

    This paper presents a new damage model for simulating fatigue-driven delamination in composite laminates. This model is developed based on the Thick Level Set approach (TLS) and provides a favorable link between damage mechanics and fracture mechanics through the non-local evaluation of the energy

  5. Level of health care and services in a tertiary health setting in Nigeria

    African Journals Online (AJOL)

    Level of health care and services in a tertiary health setting in Nigeria. ... Background: There is a growing awareness and demand for quality health care across the world; hence the ... Doctors and nurses formed 64.3% of the study population.

  6. Two Surface-Tension Formulations For The Level Set Interface-Tracking Method

    International Nuclear Information System (INIS)

    Shepel, S.V.; Smith, B.L.

    2005-01-01

    The paper describes a comparative study of two surface-tension models for the Level Set interface tracking method. In both models, the surface tension is represented as a body force, concentrated near the interface, but the technical implementation of the two options is different. The first is based on a traditional Level Set approach, in which the surface tension is distributed over a narrow band around the interface using a smoothed Delta function. In the second model, which is based on the integral form of the fluid-flow equations, the force is imposed only in those computational cells through which the interface passes. Both models have been incorporated into the Finite-Element/Finite-Volume Level Set method, previously implemented into the commercial Computational Fluid Dynamics (CFD) code CFX-4. A critical evaluation of the two models, undertaken in the context of four standard Level Set benchmark problems, shows that the first model, based on the smoothed Delta function approach, is the more general, and more robust, of the two. (author)

  7. Fast Streaming 3D Level set Segmentation on the GPU for Smooth Multi-phase Segmentation

    DEFF Research Database (Denmark)

    Sharma, Ojaswa; Zhang, Qin; Anton, François

    2011-01-01

    Level set method based segmentation provides an efficient tool for topological and geometrical shape handling, but it is slow due to high computational burden. In this work, we provide a framework for streaming computations on large volumetric images on the GPU. A streaming computational model...

  8. Multi-domain, higher order level set scheme for 3D image segmentation on the GPU

    DEFF Research Database (Denmark)

    Sharma, Ojaswa; Zhang, Qin; Anton, François

    2010-01-01

    to evaluate level set surfaces that are $C^2$ continuous, but are slow due to high computational burden. In this paper, we provide a higher order GPU based solver for fast and efficient segmentation of large volumetric images. We also extend the higher order method to multi-domain segmentation. Our streaming...

  9. An Optimized, Grid Independent, Narrow Band Data Structure for High Resolution Level Sets

    DEFF Research Database (Denmark)

    Nielsen, Michael Bang; Museth, Ken

    2004-01-01

    enforced by the convex boundaries of an underlying cartesian computational grid. Here we present a novel very memory efficient narrow band data structure, dubbed the Sparse Grid, that enables the representation of grid independent high resolution level sets. The key features our new data structure are...

  10. Determination of dose to patient in different teams of TC and assessment with international reference levels

    International Nuclear Information System (INIS)

    Ruiz Morales, C.; Fernandez lara, A. A.; Buades Forner, M. J.; Tobarra Gonzalez, B. M.

    2013-01-01

    The increase in CT studies and the differences observed between the different equipment used in our hospital prompted us to determine the doses to patients in different studies and check the results obtained with the reference values published internationally. (Author)

  11. Scope of physician procedures independently billed by mid-level providers in the office setting.

    Science.gov (United States)

    Coldiron, Brett; Ratnarathorn, Mondhipa

    2014-11-01

    Mid-level providers (nurse practitioners and physician assistants) were originally envisioned to provide primary care services in underserved areas. This study details the current scope of independent procedural billing to Medicare of difficult, invasive, and surgical procedures by medical mid-level providers. To understand the scope of independent billing to Medicare for procedures performed by mid-level providers in an outpatient office setting for a calendar year. Analyses of the 2012 Medicare Physician/Supplier Procedure Summary Master File, which reflects fee-for-service claims that were paid by Medicare, for Current Procedural Terminology procedures independently billed by mid-level providers. Outpatient office setting among health care providers. The scope of independent billing to Medicare for procedures performed by mid-level providers. In 2012, nurse practitioners and physician assistants billed independently for more than 4 million procedures at our cutoff of 5000 paid claims per procedure. Most (54.8%) of these procedures were performed in the specialty area of dermatology. The findings of this study are relevant to safety and quality of care. Recently, the shortage of primary care clinicians has prompted discussion of widening the scope of practice for mid-level providers. It would be prudent to temper widening the scope of practice of mid-level providers by recognizing that mid-level providers are not solely limited to primary care, and may involve procedures for which they may not have formal training.

  12. Online monitoring of oil film using electrical capacitance tomography and level set method

    International Nuclear Information System (INIS)

    Xue, Q.; Ma, M.; Sun, B. Y.; Cui, Z. Q.; Wang, H. X.

    2015-01-01

    In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online

  13. Basic Restriction and Reference Level in Anatomically-based Japanese Models for Low-Frequency Electric and Magnetic Field Exposures

    Science.gov (United States)

    Takano, Yukinori; Hirata, Akimasa; Fujiwara, Osamu

    Human exposed to electric and/or magnetic fields at low frequencies may cause direct effect such as nerve stimulation and excitation. Therefore, basic restriction is regulated in terms of induced current density in the ICNIRP guidelines and in-situ electric field in the IEEE standard. External electric or magnetic field which does not produce induced quantities exceeding the basic restriction is used as a reference level. The relationship between the basic restriction and reference level for low-frequency electric and magnetic fields has been investigated using European anatomic models, while limited for Japanese model, especially for electric field exposures. In addition, that relationship has not well been discussed. In the present study, we calculated the induced quantities in anatomic Japanese male and female models exposed to electric and magnetic fields at reference level. A quasi static finite-difference time-domain (FDTD) method was applied to analyze this problem. As a result, spatially averaged induced current density was found to be more sensitive to averaging algorithms than that of in-situ electric field. For electric and magnetic field exposure at the ICNIRP reference level, the maximum values of the induced current density for different averaging algorithm were smaller than the basic restriction for most cases. For exposures at the reference level in the IEEE standard, the maximum electric fields in the brain were larger than the basic restriction in the brain while smaller for the spinal cord and heart.

  14. Cell type specific DNA methylation in cord blood: A 450K-reference data set and cell count-based validation of estimated cell type composition.

    Science.gov (United States)

    Gervin, Kristina; Page, Christian Magnus; Aass, Hans Christian D; Jansen, Michelle A; Fjeldstad, Heidi Elisabeth; Andreassen, Bettina Kulle; Duijts, Liesbeth; van Meurs, Joyce B; van Zelm, Menno C; Jaddoe, Vincent W; Nordeng, Hedvig; Knudsen, Gunn Peggy; Magnus, Per; Nystad, Wenche; Staff, Anne Cathrine; Felix, Janine F; Lyle, Robert

    2016-09-01

    Epigenome-wide association studies of prenatal exposure to different environmental factors are becoming increasingly common. These studies are usually performed in umbilical cord blood. Since blood comprises multiple cell types with specific DNA methylation patterns, confounding caused by cellular heterogeneity is a major concern. This can be adjusted for using reference data consisting of DNA methylation signatures in cell types isolated from blood. However, the most commonly used reference data set is based on blood samples from adult males and is not representative of the cell type composition in neonatal cord blood. The aim of this study was to generate a reference data set from cord blood to enable correct adjustment of the cell type composition in samples collected at birth. The purity of the isolated cell types was very high for all samples (>97.1%), and clustering analyses showed distinct grouping of the cell types according to hematopoietic lineage. We explored whether this cord blood and the adult peripheral blood reference data sets impact the estimation of cell type composition in cord blood samples from an independent birth cohort (MoBa, n = 1092). This revealed significant differences for all cell types. Importantly, comparison of the cell type estimates against matched cell counts both in the cord blood reference samples (n = 11) and in another independent birth cohort (Generation R, n = 195), demonstrated moderate to high correlation of the data. This is the first cord blood reference data set with a comprehensive examination of the downstream application of the data through validation of estimated cell types against matched cell counts.

  15. The importance of information on relatives for the prediction of genomic breeding values and the implications for the makeup of reference data sets in livestock breeding schemes.

    Science.gov (United States)

    Clark, Samuel A; Hickey, John M; Daetwyler, Hans D; van der Werf, Julius H J

    2012-02-09

    The theory of genomic selection is based on the prediction of the effects of genetic markers in linkage disequilibrium with quantitative trait loci. However, genomic selection also relies on relationships between individuals to accurately predict genetic value. This study aimed to examine the importance of information on relatives versus that of unrelated or more distantly related individuals on the estimation of genomic breeding values. Simulated and real data were used to examine the effects of various degrees of relationship on the accuracy of genomic selection. Genomic Best Linear Unbiased Prediction (gBLUP) was compared to two pedigree based BLUP methods, one with a shallow one generation pedigree and the other with a deep ten generation pedigree. The accuracy of estimated breeding values for different groups of selection candidates that had varying degrees of relationships to a reference data set of 1750 animals was investigated. The gBLUP method predicted breeding values more accurately than BLUP. The most accurate breeding values were estimated using gBLUP for closely related animals. Similarly, the pedigree based BLUP methods were also accurate for closely related animals, however when the pedigree based BLUP methods were used to predict unrelated animals, the accuracy was close to zero. In contrast, gBLUP breeding values, for animals that had no pedigree relationship with animals in the reference data set, allowed substantial accuracy. An animal's relationship to the reference data set is an important factor for the accuracy of genomic predictions. Animals that share a close relationship to the reference data set had the highest accuracy from genomic predictions. However a baseline accuracy that is driven by the reference data set size and the overall population effective population size enables gBLUP to estimate a breeding value for unrelated animals within a population (breed), using information previously ignored by pedigree based BLUP methods.

  16. INTEGRATED SFM TECHNIQUES USING DATA SET FROM GOOGLE EARTH 3D MODEL AND FROM STREET LEVEL

    Directory of Open Access Journals (Sweden)

    L. Inzerillo

    2017-08-01

    Full Text Available Structure from motion (SfM represents a widespread photogrammetric method that uses the photogrammetric rules to carry out a 3D model from a photo data set collection. Some complex ancient buildings, such as Cathedrals, or Theatres, or Castles, etc. need to implement the data set (realized from street level with the UAV one in order to have the 3D roof reconstruction. Nevertheless, the use of UAV is strong limited from the government rules. In these last years, Google Earth (GE has been enriched with the 3D models of the earth sites. For this reason, it seemed convenient to start to test the potentiality offered by GE in order to extract from it a data set that replace the UAV function, to close the aerial building data set, using screen images of high resolution 3D models. Users can take unlimited “aerial photos” of a scene while flying around in GE at any viewing angle and altitude. The challenge is to verify the metric reliability of the SfM model carried out with an integrated data set (the one from street level and the one from GE aimed at replace the UAV use in urban contest. This model is called integrated GE SfM model (i-GESfM. In this paper will be present a case study: the Cathedral of Palermo.

  17. Establishment of institutional diagnostic reference level for computed tomography with automated dose-tracking software.

    Science.gov (United States)

    Liang, Chong R; Chen, Priscilla X H; Kapur, Jeevesh; Ong, Michael K L; Quek, Swee T; Kapur, Subhash C

    2017-06-01

    The aim of this study was to establish institutional diagnostic reference levels (DRLs) by summarising doses collected across the five computed tomography (CT) system in our institution. CT dose data of 15940 patients were collected retrospectively from May 2015 to October 2015 in five institutional scanners. The mean, 75th percentile and 90th percentile of the dose spread were calculated according to anatomic region. The common CT examinations such as head, chest, combined abdomen/pelvis (A/P), and combined chest/abdomen/pelvis (C/A/P) were reviewed. Distribution of CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED) were extracted from the data for single-phasic and multiphasic examinations. The institutional DRL for our CT units were established as mean (50th percentile) of CTDIvol (mGy), DLP (mGy.cm) and ED (mSv) for single and multiphasic studies using the dose-tracking software. In single phasic examination, Head: (49.0 mGy), (978.0 mGy.cm), (2.4 mSv) respectively; Chest: (6.0 mGy), (254.0 mGy.cm), (4.9 mSv) respectively; CT A/P (10.0 mGy), (514.0 mGy.cm), (8.9 mSv) respectively; CT C/A/P (10.0 mGy), (674.0 mGy.cm), (11.8 mSv) respectively. In multiphasic studies: Head (45.0 mGy), (1822.0 mGy.cm), (5.0 mSv) respectively; Chest (8.0 mGy), (577.0 mGy.cm), (10.0 mSv) respectively; CT A/P: (10.0 mGy), (1153.0 mGy.cm), (20.2 mSv) respectively; CT C/A/P: (11.0 mGy), (1090.0 mGy.cm), (19.2 mSv) respectively. The reported metrics offer a variety of information that institutions can use for quality improvement activities. The variations in dose between scanners suggest a large potential for optimisation of radiation dose. © 2017 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.

  18. Study of the structure and development of the set of reference materials of composition and structure of heat resisting nickel and intermetallic alloys

    Directory of Open Access Journals (Sweden)

    E. B. Chabina

    2016-01-01

    Full Text Available Relevance of research: There are two sizes (several microns and nanodimensional of strengthening j'-phase in single-crystal heat resisting nickel and intermetallic alloys, used for making blades of modern gas turbine engines (GTD. For in-depth study of structural and phase condition of such alloys not only qualitative description of created structure is necessary, but quantitative analysis of alloy components geometrical characteristics. Purpose of the work: Development of reference material sets of heat resisting nickel and intermetallic alloy composition and structure. Research methods: To address the measurement problem of control of structural and geometrical characteristics of single-crystal heat resisting and intermetallic alloys by analytical microscopy and X-ray diffraction analysis the research was carried out using certified measurement techniques on facilities, entered in the Register of Measurement Means of the Russian Federation. The research was carried out on microsections, foils and plates, cut in the plane {100}. Results: It is established that key parameters, defining the properties of these alloys are particle size of strengthening j' -phase, the layer thickness of j-phase between them and parameters of phases lattice. Metrological requirements for reference materials of composition and structure of heat resisting nickel and intermetallic alloys are formulated. The necessary and sufficient reference material set providing the possibility to determine the composition and structure parameters of single-crystal heat resisting nickel and intermetallic alloys is defined. The developed RM sets are certified as in-plant reference materials. Conclusion: The reference materials can be used for graduation of spectral equipment when conducting element analysis of specified class alloys; for calibration of means of measuring alloy structure parameters; for measurement of alloys phases lattice parameters; for structure reference pictures

  19. Evaluation and management of patients referred to a tertiary-level ...

    African Journals Online (AJOL)

    has been associated with two-thirds of strokes and almost half of ischaemic heart ... individuals with hypertension were on treatment, and of these only ... There are few published data on the control of hypertension and ... We therefore conducted a prospective study of patients referred ..... A recent meta-analysis by Briasoulis.

  20. Level set segmentation of bovine corpora lutea in ex situ ovarian ultrasound images

    Directory of Open Access Journals (Sweden)

    Adams Gregg P

    2008-08-01

    Full Text Available Abstract Background The objective of this study was to investigate the viability of level set image segmentation methods for the detection of corpora lutea (corpus luteum, CL boundaries in ultrasonographic ovarian images. It was hypothesized that bovine CL boundaries could be located within 1–2 mm by a level set image segmentation methodology. Methods Level set methods embed a 2D contour in a 3D surface and evolve that surface over time according to an image-dependent speed function. A speed function suitable for segmentation of CL's in ovarian ultrasound images was developed. An initial contour was manually placed and contour evolution was allowed to proceed until the rate of change of the area was sufficiently small. The method was tested on ovarian ultrasonographic images (n = 8 obtained ex situ. A expert in ovarian ultrasound interpretation delineated CL boundaries manually to serve as a "ground truth". Accuracy of the level set segmentation algorithm was determined by comparing semi-automatically determined contours with ground truth contours using the mean absolute difference (MAD, root mean squared difference (RMSD, Hausdorff distance (HD, sensitivity, and specificity metrics. Results and discussion The mean MAD was 0.87 mm (sigma = 0.36 mm, RMSD was 1.1 mm (sigma = 0.47 mm, and HD was 3.4 mm (sigma = 2.0 mm indicating that, on average, boundaries were accurate within 1–2 mm, however, deviations in excess of 3 mm from the ground truth were observed indicating under- or over-expansion of the contour. Mean sensitivity and specificity were 0.814 (sigma = 0.171 and 0.990 (sigma = 0.00786, respectively, indicating that CLs were consistently undersegmented but rarely did the contour interior include pixels that were judged by the human expert not to be part of the CL. It was observed that in localities where gradient magnitudes within the CL were strong due to high contrast speckle, contour expansion stopped too early. Conclusion The

  1. Image-guided regularization level set evolution for MR image segmentation and bias field correction.

    Science.gov (United States)

    Wang, Lingfeng; Pan, Chunhong

    2014-01-01

    Magnetic resonance (MR) image segmentation is a crucial step in surgical and treatment planning. In this paper, we propose a level-set-based segmentation method for MR images with intensity inhomogeneous problem. To tackle the initialization sensitivity problem, we propose a new image-guided regularization to restrict the level set function. The maximum a posteriori inference is adopted to unify segmentation and bias field correction within a single framework. Under this framework, both the contour prior and the bias field prior are fully used. As a result, the image intensity inhomogeneity can be well solved. Extensive experiments are provided to evaluate the proposed method, showing significant improvements in both segmentation and bias field correction accuracies as compared with other state-of-the-art approaches. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Level Set Projection Method for Incompressible Navier-Stokes on Arbitrary Boundaries

    KAUST Repository

    Williams-Rioux, Bertrand

    2012-01-12

    Second order level set projection method for incompressible Navier-Stokes equations is proposed to solve flow around arbitrary geometries. We used rectilinear grid with collocated cell centered velocity and pressure. An explicit Godunov procedure is used to address the nonlinear advection terms, and an implicit Crank-Nicholson method to update viscous effects. An approximate pressure projection is implemented at the end of the time stepping using multigrid as a conventional fast iterative method. The level set method developed by Osher and Sethian [17] is implemented to address real momentum and pressure boundary conditions by the advection of a distance function, as proposed by Aslam [3]. Numerical results for the Strouhal number and drag coefficients validated the model with good accuracy for flow over a cylinder in the parallel shedding regime (47 < Re < 180). Simulations for an array of cylinders and an oscillating cylinder were performed, with the latter demonstrating our methods ability to handle dynamic boundary conditions.

  3. Automatic segmentation of Leishmania parasite in microscopic images using a modified CV level set method

    Science.gov (United States)

    Farahi, Maria; Rabbani, Hossein; Talebi, Ardeshir; Sarrafzadeh, Omid; Ensafi, Shahab

    2015-12-01

    Visceral Leishmaniasis is a parasitic disease that affects liver, spleen and bone marrow. According to World Health Organization report, definitive diagnosis is possible just by direct observation of the Leishman body in the microscopic image taken from bone marrow samples. We utilize morphological and CV level set method to segment Leishman bodies in digital color microscopic images captured from bone marrow samples. Linear contrast stretching method is used for image enhancement and morphological method is applied to determine the parasite regions and wipe up unwanted objects. Modified global and local CV level set methods are proposed for segmentation and a shape based stopping factor is used to hasten the algorithm. Manual segmentation is considered as ground truth to evaluate the proposed method. This method is tested on 28 samples and achieved 10.90% mean of segmentation error for global model and 9.76% for local model.

  4. A Cartesian Adaptive Level Set Method for Two-Phase Flows

    Science.gov (United States)

    Ham, F.; Young, Y.-N.

    2003-01-01

    In the present contribution we develop a level set method based on local anisotropic Cartesian adaptation as described in Ham et al. (2002). Such an approach should allow for the smallest possible Cartesian grid capable of resolving a given flow. The remainder of the paper is organized as follows. In section 2 the level set formulation for free surface calculations is presented and its strengths and weaknesses relative to the other free surface methods reviewed. In section 3 the collocated numerical method is described. In section 4 the method is validated by solving the 2D and 3D drop oscilation problem. In section 5 we present some results from more complex cases including the 3D drop breakup in an impulsively accelerated free stream, and the 3D immiscible Rayleigh-Taylor instability. Conclusions are given in section 6.

  5. A level-set method for two-phase flows with soluble surfactant

    Science.gov (United States)

    Xu, Jian-Jun; Shi, Weidong; Lai, Ming-Chih

    2018-01-01

    A level-set method is presented for solving two-phase flows with soluble surfactant. The Navier-Stokes equations are solved along with the bulk surfactant and the interfacial surfactant equations. In particular, the convection-diffusion equation for the bulk surfactant on the irregular moving domain is solved by using a level-set based diffusive-domain method. A conservation law for the total surfactant mass is derived, and a re-scaling procedure for the surfactant concentrations is proposed to compensate for the surfactant mass loss due to numerical diffusion. The whole numerical algorithm is easy for implementation. Several numerical simulations in 2D and 3D show the effects of surfactant solubility on drop dynamics under shear flow.

  6. Application of the level set method for multi-phase flow computation in fusion engineering

    International Nuclear Information System (INIS)

    Luo, X-Y.; Ni, M-J.; Ying, A.; Abdou, M.

    2006-01-01

    Numerical simulation of multi-phase flow is essential to evaluate the feasibility of a liquid protection scheme for the power plant chamber. The level set method is one of the best methods for computing and analyzing the motion of interface among the multi-phase flow. This paper presents a general formula for the second-order projection method combined with the level set method to simulate unsteady incompressible multi-phase flow with/out phase change flow encountered in fusion science and engineering. The third-order ENO scheme and second-order semi-implicit Crank-Nicholson scheme is used to update the convective and diffusion term. The numerical results show this method can handle the complex deformation of the interface and the effect of liquid-vapor phase change will be included in the future work

  7. Embedded Real-Time Architecture for Level-Set-Based Active Contours

    Directory of Open Access Journals (Sweden)

    Dejnožková Eva

    2005-01-01

    Full Text Available Methods described by partial differential equations have gained a considerable interest because of undoubtful advantages such as an easy mathematical description of the underlying physics phenomena, subpixel precision, isotropy, or direct extension to higher dimensions. Though their implementation within the level set framework offers other interesting advantages, their vast industrial deployment on embedded systems is slowed down by their considerable computational effort. This paper exploits the high parallelization potential of the operators from the level set framework and proposes a scalable, asynchronous, multiprocessor platform suitable for system-on-chip solutions. We concentrate on obtaining real-time execution capabilities. The performance is evaluated on a continuous watershed and an object-tracking application based on a simple gradient-based attraction force driving the active countour. The proposed architecture can be realized on commercially available FPGAs. It is built around general-purpose processor cores, and can run code developed with usual tools.

  8. Level-set-based reconstruction algorithm for EIT lung images: first clinical results.

    Science.gov (United States)

    Rahmati, Peyman; Soleimani, Manuchehr; Pulletz, Sven; Frerichs, Inéz; Adler, Andy

    2012-05-01

    We show the first clinical results using the level-set-based reconstruction algorithm for electrical impedance tomography (EIT) data. The level-set-based reconstruction method (LSRM) allows the reconstruction of non-smooth interfaces between image regions, which are typically smoothed by traditional voxel-based reconstruction methods (VBRMs). We develop a time difference formulation of the LSRM for 2D images. The proposed reconstruction method is applied to reconstruct clinical EIT data of a slow flow inflation pressure-volume manoeuvre in lung-healthy and adult lung-injury patients. Images from the LSRM and the VBRM are compared. The results show comparable reconstructed images, but with an improved ability to reconstruct sharp conductivity changes in the distribution of lung ventilation using the LSRM.

  9. Level-set-based reconstruction algorithm for EIT lung images: first clinical results

    International Nuclear Information System (INIS)

    Rahmati, Peyman; Adler, Andy; Soleimani, Manuchehr; Pulletz, Sven; Frerichs, Inéz

    2012-01-01

    We show the first clinical results using the level-set-based reconstruction algorithm for electrical impedance tomography (EIT) data. The level-set-based reconstruction method (LSRM) allows the reconstruction of non-smooth interfaces between image regions, which are typically smoothed by traditional voxel-based reconstruction methods (VBRMs). We develop a time difference formulation of the LSRM for 2D images. The proposed reconstruction method is applied to reconstruct clinical EIT data of a slow flow inflation pressure–volume manoeuvre in lung-healthy and adult lung-injury patients. Images from the LSRM and the VBRM are compared. The results show comparable reconstructed images, but with an improved ability to reconstruct sharp conductivity changes in the distribution of lung ventilation using the LSRM. (paper)

  10. Kir2.1 channels set two levels of resting membrane potential with inward rectification.

    Science.gov (United States)

    Chen, Kuihao; Zuo, Dongchuan; Liu, Zheng; Chen, Haijun

    2018-04-01

    Strong inward rectifier K + channels (Kir2.1) mediate background K + currents primarily responsible for maintenance of resting membrane potential. Multiple types of cells exhibit two levels of resting membrane potential. Kir2.1 and K2P1 currents counterbalance, partially accounting for the phenomenon of human cardiomyocytes in subphysiological extracellular K + concentrations or pathological hypokalemic conditions. The mechanism of how Kir2.1 channels contribute to the two levels of resting membrane potential in different types of cells is not well understood. Here we test the hypothesis that Kir2.1 channels set two levels of resting membrane potential with inward rectification. Under hypokalemic conditions, Kir2.1 currents counterbalance HCN2 or HCN4 cation currents in CHO cells that heterologously express both channels, generating N-shaped current-voltage relationships that cross the voltage axis three times and reconstituting two levels of resting membrane potential. Blockade of HCN channels eliminated the phenomenon in K2P1-deficient Kir2.1-expressing human cardiomyocytes derived from induced pluripotent stem cells or CHO cells expressing both Kir2.1 and HCN2 channels. Weakly inward rectifier Kir4.1 or inward rectification-deficient Kir2.1•E224G mutant channels do not set such two levels of resting membrane potential when co-expressed with HCN2 channels in CHO cells or when overexpressed in human cardiomyocytes derived from induced pluripotent stem cells. These findings demonstrate a common mechanism that Kir2.1 channels set two levels of resting membrane potential with inward rectification by balancing inward currents through different cation channels such as hyperpolarization-activated HCN channels or hypokalemia-induced K2P1 leak channels.

  11. Reconstruction of incomplete cell paths through a 3D-2D level set segmentation

    Science.gov (United States)

    Hariri, Maia; Wan, Justin W. L.

    2012-02-01

    Segmentation of fluorescent cell images has been a popular technique for tracking live cells. One challenge of segmenting cells from fluorescence microscopy is that cells in fluorescent images frequently disappear. When the images are stacked together to form a 3D image volume, the disappearance of the cells leads to broken cell paths. In this paper, we present a segmentation method that can reconstruct incomplete cell paths. The key idea of this model is to perform 2D segmentation in a 3D framework. The 2D segmentation captures the cells that appear in the image slices while the 3D segmentation connects the broken cell paths. The formulation is similar to the Chan-Vese level set segmentation which detects edges by comparing the intensity value at each voxel with the mean intensity values inside and outside of the level set surface. Our model, however, performs the comparison on each 2D slice with the means calculated by the 2D projected contour. The resulting effect is to segment the cells on each image slice. Unlike segmentation on each image frame individually, these 2D contours together form the 3D level set function. By enforcing minimum mean curvature on the level set surface, our segmentation model is able to extend the cell contours right before (and after) the cell disappears (and reappears) into the gaps, eventually connecting the broken paths. We will present segmentation results of C2C12 cells in fluorescent images to illustrate the effectiveness of our model qualitatively and quantitatively by different numerical examples.

  12. Computing the dynamics of biomembranes by combining conservative level set and adaptive finite element methods

    OpenAIRE

    Laadhari , Aymen; Saramito , Pierre; Misbah , Chaouqi

    2014-01-01

    International audience; The numerical simulation of the deformation of vesicle membranes under simple shear external fluid flow is considered in this paper. A new saddle-point approach is proposed for the imposition of the fluid incompressibility and the membrane inextensibility constraints, through Lagrange multipliers defined in the fluid and on the membrane respectively. Using a level set formulation, the problem is approximated by mixed finite elements combined with an automatic adaptive ...

  13. Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shenggao, E-mail: sgzhou@suda.edu.cn, E-mail: bli@math.ucsd.edu [Department of Mathematics and Mathematical Center for Interdiscipline Research, Soochow University, 1 Shizi Street, Jiangsu, Suzhou 215006 (China); Sun, Hui; Cheng, Li-Tien [Department of Mathematics, University of California, San Diego, La Jolla, California 92093-0112 (United States); Dzubiella, Joachim [Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin, Germany and Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Li, Bo, E-mail: sgzhou@suda.edu.cn, E-mail: bli@math.ucsd.edu [Department of Mathematics and Quantitative Biology Graduate Program, University of California, San Diego, La Jolla, California 92093-0112 (United States); McCammon, J. Andrew [Department of Chemistry and Biochemistry, Department of Pharmacology, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093-0365 (United States)

    2016-08-07

    Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the “normal velocity” that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the

  14. Pilot-benchmarking of the WENRA safety reference levels for the spent fuel intermediate storage facility Ahaus

    International Nuclear Information System (INIS)

    Lorenz, Bernd; Roeder, Markus; Brandt, Klaus-Dieter

    2008-01-01

    Full text: The Western European Nuclear Regulator's Association (WENRA) has 2007 issued the draft of the 'Waste and Spent Fuel Storage Safety Reference Levels'. The objective of WENRA is to strive for a harmonized safety level of nuclear facilities within the European Community and these Reference Levels are a benchmark method to demonstrate the achieved level for the regulatory system and the implementation as well. Safety Reference Levels exist at the moment for Reactor Safety, Waste Storage and Decommissioning in different stages of development. ENISS, the European Nuclear Installations Safety Standards Initiative, a FORATOM based special organisation of nuclear operators, has discussed these Safety Reference Levels very intensively with WENRA and the agreement was to make a implementation benchmark-exercise for the storage facilities before the authorities finally agree on the Reference Levels. This benchmark was scheduled for the year 2008. Because of the special situation in Germany where a large number of storage facilities is in operation the German authorities felt that it would be useful to initiate a Pilot-Benchmark to get first results on the feasibility of the Reference Levels and the burden imposed to authorities and operators by these benchmark-exercises. GNS, a subsidiary company of the utilities, agreed to step into this process on a voluntary basis with its storage facility for spent fuel in Ahaus. The exercise was done in a very efficient way and in good co-operation between the authorities, local and federal, and the operator. The results in terms of safety assessments have been very satisfactory showing the high degree of safety. Although the facility was for the first time licensed already in 1987 the compliance with nearly all Reference Levels from 2007 could be demonstrated. It became also clear that newer facilities would fulfil the desired safety standard too. Nevertheless, in spite of the good results the exercise revealed some weak

  15. Some free boundary problems in potential flow regime usinga based level set method

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, M.; Bobillo-Ares, N.; Sethian, J.A.

    2008-12-09

    Recent advances in the field of fluid mechanics with moving fronts are linked to the use of Level Set Methods, a versatile mathematical technique to follow free boundaries which undergo topological changes. A challenging class of problems in this context are those related to the solution of a partial differential equation posed on a moving domain, in which the boundary condition for the PDE solver has to be obtained from a partial differential equation defined on the front. This is the case of potential flow models with moving boundaries. Moreover the fluid front will possibly be carrying some material substance which will diffuse in the front and be advected by the front velocity, as for example the use of surfactants to lower surface tension. We present a Level Set based methodology to embed this partial differential equations defined on the front in a complete Eulerian framework, fully avoiding the tracking of fluid particles and its known limitations. To show the advantages of this approach in the field of Fluid Mechanics we present in this work one particular application: the numerical approximation of a potential flow model to simulate the evolution and breaking of a solitary wave propagating over a slopping bottom and compare the level set based algorithm with previous front tracking models.

  16. A level set method for cupping artifact correction in cone-beam CT

    International Nuclear Information System (INIS)

    Xie, Shipeng; Li, Haibo; Ge, Qi; Li, Chunming

    2015-01-01

    Purpose: To reduce cupping artifacts and improve the contrast-to-noise ratio in cone-beam computed tomography (CBCT). Methods: A level set method is proposed to reduce cupping artifacts in the reconstructed image of CBCT. The authors derive a local intensity clustering property of the CBCT image and define a local clustering criterion function of the image intensities in a neighborhood of each point. This criterion function defines an energy in terms of the level set functions, which represent a segmentation result and the cupping artifacts. The cupping artifacts are estimated as a result of minimizing this energy. Results: The cupping artifacts in CBCT are reduced by an average of 90%. The results indicate that the level set-based algorithm is practical and effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. Conclusions: The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented, and provides cupping correction through a single-scan acquisition. The experimental results demonstrate that the proposed method successfully reduces the cupping artifacts

  17. Level-set simulations of buoyancy-driven motion of single and multiple bubbles

    International Nuclear Information System (INIS)

    Balcázar, Néstor; Lehmkuhl, Oriol; Jofre, Lluís; Oliva, Assensi

    2015-01-01

    Highlights: • A conservative level-set method is validated and verified. • An extensive study of buoyancy-driven motion of single bubbles is performed. • The interactions of two spherical and ellipsoidal bubbles is studied. • The interaction of multiple bubbles is simulated in a vertical channel. - Abstract: This paper presents a numerical study of buoyancy-driven motion of single and multiple bubbles by means of the conservative level-set method. First, an extensive study of the hydrodynamics of single bubbles rising in a quiescent liquid is performed, including its shape, terminal velocity, drag coefficients and wake patterns. These results are validated against experimental and numerical data well established in the scientific literature. Then, a further study on the interaction of two spherical and ellipsoidal bubbles is performed for different orientation angles. Finally, the interaction of multiple bubbles is explored in a periodic vertical channel. The results show that the conservative level-set approach can be used for accurate modelling of bubble dynamics. Moreover, it is demonstrated that the present method is numerically stable for a wide range of Morton and Reynolds numbers.

  18. Stabilized Conservative Level Set Method with Adaptive Wavelet-based Mesh Refinement

    Science.gov (United States)

    Shervani-Tabar, Navid; Vasilyev, Oleg V.

    2016-11-01

    This paper addresses one of the main challenges of the conservative level set method, namely the ill-conditioned behavior of the normal vector away from the interface. An alternative formulation for reconstruction of the interface is proposed. Unlike the commonly used methods which rely on the unit normal vector, Stabilized Conservative Level Set (SCLS) uses a modified renormalization vector with diminishing magnitude away from the interface. With the new formulation, in the vicinity of the interface the reinitialization procedure utilizes compressive flux and diffusive terms only in the normal direction to the interface, thus, preserving the conservative level set properties, while away from the interfaces the directional diffusion mechanism automatically switches to homogeneous diffusion. The proposed formulation is robust and general. It is especially well suited for use with adaptive mesh refinement (AMR) approaches due to need for a finer resolution in the vicinity of the interface in comparison with the rest of the domain. All of the results were obtained using the Adaptive Wavelet Collocation Method, a general AMR-type method, which utilizes wavelet decomposition to adapt on steep gradients in the solution while retaining a predetermined order of accuracy.

  19. Considering Actionability at the Participant's Research Setting Level for Anticipatable Incidental Findings from Clinical Research.

    Science.gov (United States)

    Ortiz-Osorno, Alberto Betto; Ehler, Linda A; Brooks, Judith

    2015-01-01

    Determining what constitutes an anticipatable incidental finding (IF) from clinical research and defining whether, and when, this IF should be returned to the participant have been topics of discussion in the field of human subject protections for the last 10 years. It has been debated that implementing a comprehensive IF-approach that addresses both the responsibility of researchers to return IFs and the expectation of participants to receive them can be logistically challenging. IFs have been debated at different levels, such as the ethical reasoning for considering their disclosure or the need for planning for them during the development of the research study. Some authors have discussed the methods for re-contacting participants for disclosing IFs, as well as the relevance of considering the clinical importance of the IFs. Similarly, other authors have debated about when IFs should be disclosed to participants. However, no author has addressed how the "actionability" of the IFs should be considered, evaluated, or characterized at the participant's research setting level. This paper defines the concept of "Actionability at the Participant's Research Setting Level" (APRSL) for anticipatable IFs from clinical research, discusses some related ethical concepts to justify the APRSL concept, proposes a strategy to incorporate APRSL into the planning and management of IFs, and suggests a strategy for integrating APRSL at each local research setting. © 2015 American Society of Law, Medicine & Ethics, Inc.

  20. Records for radioactive waste management up to repository closure: Managing the primary level information (PLI) set

    International Nuclear Information System (INIS)

    2004-07-01

    The objective of this publication is to highlight the importance of the early establishment of a comprehensive records system to manage primary level information (PLI) as an integrated set of information, not merely as a collection of information, throughout all the phases of radioactive waste management. Early establishment of a comprehensive records system to manage Primary Level Information as an integrated set of information throughout all phases of radioactive waste management is important. In addition to the information described in the waste inventory record keeping system (WIRKS), the PLI of a radioactive waste repository consists of the entire universe of information, data and records related to any aspect of the repository's life cycle. It is essential to establish PLI requirements based on integrated set of needs from Regulators and Waste Managers involved in the waste management chain and to update these requirements as needs change over time. Information flow for radioactive waste management should be back-end driven. Identification of an Authority that will oversee the management of PLI throughout all phases of the radioactive waste management life cycle would guarantee the information flow to future generations. The long term protection of information essential to future generations can only be assured by the timely establishment of a comprehensive and effective RMS capable of capturing, indexing and evaluating all PLI. The loss of intellectual control over the PLI will make it very difficult to subsequently identify the ILI and HLI information sets. At all times prior to the closure of a radioactive waste repository, there should be an identifiable entity with a legally enforceable financial and management responsibility for the continued operation of a PLI Records Management System. The information presented in this publication will assist Member States in ensuring that waste and repository records, relevant for retention after repository closure

  1. Low and intermediate level waste in SFR-1. Reference Waste Inventory 2007

    Energy Technology Data Exchange (ETDEWEB)

    Almkvist, Lisa (Vattenfall Power Consultant AB, Stockholm (SE)); Gordon, Anna (Swedish Nuclear Fuel and Waste Management Co., Stockholm (SE))

    2007-11-15

    The objective with this report is to describe all the waste and the waste package that is expected to be deposited in SFR 1 at the time of closure. The report will form the basis for the release calculation in the safety analysis for SFR 1. Three different scenarios are explored in this report; the waste inventory is based on an estimated operational lifetime of the Swedish nuclear power plants of 50 and 60 years and that closure of the SFR 1 repository will take place in 2040 or 2050 respectively. The third scenario is where the repository is full (one part where the activity adds up to 1016 Bq and one part where the repository is considered full regarding volume). In the report, data about geometries, weights, materials, chemicals and radionuclide are given. No chemotoxic material has been identified in the waste. The inventory is estimated using the Prosit-interface which extracts information from the Triumf database. The inventory is based on so called 'waste types' and the waste types' 'reference waste package'. The reference waste package combined with a prognosis of the number of waste packages to be delivered to SFR 1 gives the final waste inventory for SFR 1. All reference waste packages are thoroughly described in the appendices of this report. The reference waste packages are as far as possible based on actual experiences and measurements. The radionuclide inventory is also based on actual measurements. The inventory is based on measurements of 60Co and 137Cs in waste packages and on measurements of 239Pu and 240Pu in reactor water. Other nuclides in the inventory are calculated with correlation factors

  2. Low and intermediate level waste in SFR-1. Reference waste inventory

    International Nuclear Information System (INIS)

    Riggare, P.; Johansson, Claes

    2001-06-01

    The objective with this report is to describe all the waste and the waste package that is expected to be deposited in SFR-1 at the time of closure. This report is a part of the SAFE project (Safety Assessment of Final Repository for Radioactive Operational Waste), i.e. the renewed safety assessment of SFR-1. The accounted waste inventory has been used as input to the release calculation that has been performed in the SAFE project. The waste inventory is based on an estimated operational lifetime of the Swedish nuclear power plants of 40 years and that closure of the SFR repository will happen in 2030. In the report, data about geometries, weights, materials, chemicals and radionuclide are given. No chemo toxic material has been identified in the waste. The inventory is based on so called waste types and the waste types reference waste package. The reference waste package combined with a prognosis of the number of waste packages to the year 2030 gives the final waste inventory for SFR-1. All reference waste packages are thoroughly described in the appendices of this report. The reference waste packages are as far as possible based on actual experiences and measurements. The radionuclide inventory is also based on actual measurements. The inventory is based on measurements of 60 Co and 137 Cs in waste packages and on measurements 239 Pu and 240 Pu in reactor water. Other nuclides in the inventory are calculated with correlation factors. In the SAFE project's prerequisites it was said that one realistic and one conservative (pessimistic) inventory should be produced. The conservative one should then be used for the release calculations. In this report one realistic and one conservative radionuclide inventory is presented. The conservative one adds up to 10 16 Bq. Regarding materials there is only one inventory given since it is not certain what is a conservative assumption

  3. Low and intermediate level waste in SFR-1. Reference Waste Inventory 2007

    International Nuclear Information System (INIS)

    Almkvist, Lisa; Gordon, Ann

    2007-11-01

    The objective with this report is to describe all the waste and the waste package that is expected to be deposited in SFR 1 at the time of closure. The report will form the basis for the release calculation in the safety analysis for SFR 1. Three different scenarios are explored in this report; the waste inventory is based on an estimated operational lifetime of the Swedish nuclear power plants of 50 and 60 years and that closure of the SFR 1 repository will take place in 2040 or 2050 respectively. The third scenario is where the repository is full (one part where the activity adds up to 1016 Bq and one part where the repository is considered full regarding volume). In the report, data about geometries, weights, materials, chemicals and radionuclide are given. No chemotoxic material has been identified in the waste. The inventory is estimated using the Prosit-interface which extracts information from the Triumf database. The inventory is based on so called 'waste types' and the waste types' 'reference waste package'. The reference waste package combined with a prognosis of the number of waste packages to be delivered to SFR 1 gives the final waste inventory for SFR 1. All reference waste packages are thoroughly described in the appendices of this report. The reference waste packages are as far as possible based on actual experiences and measurements. The radionuclide inventory is also based on actual measurements. The inventory is based on measurements of 60 Co and 137 Cs in waste packages and on measurements of 239 Pu and 240 Pu in reactor water. Other nuclides in the inventory are calculated with correlation factors

  4. Topological Hausdorff dimension and level sets of generic continuous functions on fractals

    International Nuclear Information System (INIS)

    Balka, Richárd; Buczolich, Zoltán; Elekes, Márton

    2012-01-01

    Highlights: ► We examine a new fractal dimension, the so called topological Hausdorff dimension. ► The generic continuous function has a level set of maximal Hausdorff dimension. ► This maximal dimension is the topological Hausdorff dimension minus one. ► Homogeneity implies that “most” level sets are of this dimension. ► We calculate the various dimensions of the graph of the generic function. - Abstract: In an earlier paper we introduced a new concept of dimension for metric spaces, the so called topological Hausdorff dimension. For a compact metric space K let dim H K and dim tH K denote its Hausdorff and topological Hausdorff dimension, respectively. We proved that this new dimension describes the Hausdorff dimension of the level sets of the generic continuous function on K, namely sup{ dim H f -1 (y):y∈R} =dim tH K-1 for the generic f ∈ C(K), provided that K is not totally disconnected, otherwise every non-empty level set is a singleton. We also proved that if K is not totally disconnected and sufficiently homogeneous then dim H f −1 (y) = dim tH K − 1 for the generic f ∈ C(K) and the generic y ∈ f(K). The most important goal of this paper is to make these theorems more precise. As for the first result, we prove that the supremum is actually attained on the left hand side of the first equation above, and also show that there may only be a unique level set of maximal Hausdorff dimension. As for the second result, we characterize those compact metric spaces for which for the generic f ∈ C(K) and the generic y ∈ f(K) we have dim H f −1 (y) = dim tH K − 1. We also generalize a result of B. Kirchheim by showing that if K is self-similar then for the generic f ∈ C(K) for every y∈intf(K) we have dim H f −1 (y) = dim tH K − 1. Finally, we prove that the graph of the generic f ∈ C(K) has the same Hausdorff and topological Hausdorff dimension as K.

  5. Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values

    Energy Technology Data Exchange (ETDEWEB)

    Ubeda, Carlos, E-mail: cubeda@uta.cl [Medical Technology Department, Radiological Sciences Center, Health Sciences Faculty, Tarapaca University, Arica 1000000 (Chile); Miranda, Patricia [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Santiago 7500539 (Chile); Vano, Eliseo [Radiology Department, Faculty of Medicine, Complutense University and IdIS, San Carlos Hospital, Madrid 28040 (Spain)

    2015-02-15

    Purpose: To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. Methods: Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. Results: Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for <1 yr; 213 for 1 to <5 yr; 82 for 5 to <10 yr; and 102 for 10 to <16 yr. The third quartile values obtained for DAP by diagnostic and therapeutic procedures and age range were 1.17 and 1.11 Gy cm{sup 2} for <1 yr; 1.74 and 1.90 Gy cm{sup 2} for 1 to <5 yr; 2.83 and 3.22 Gy cm{sup 2} for 5 to <10 yr; and 7.34 and 8.68 Gy cm{sup 2} for 10 to <16 yr, respectively. The third quartile value obtained for the DAP/body weight ratio for the full sample of procedures was 0.17 (Gy cm{sup 2}/kg) for diagnostic and therapeutic procedures. Conclusions: The data presented in this paper are an initial attempt at establishing local DRLs in pediatric interventional cardiology, from a large sample of procedures for the standard age bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there

  6. Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values

    International Nuclear Information System (INIS)

    Ubeda, Carlos; Miranda, Patricia; Vano, Eliseo

    2015-01-01

    Purpose: To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. Methods: Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. Results: Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for <1 yr; 213 for 1 to <5 yr; 82 for 5 to <10 yr; and 102 for 10 to <16 yr. The third quartile values obtained for DAP by diagnostic and therapeutic procedures and age range were 1.17 and 1.11 Gy cm 2 for <1 yr; 1.74 and 1.90 Gy cm 2 for 1 to <5 yr; 2.83 and 3.22 Gy cm 2 for 5 to <10 yr; and 7.34 and 8.68 Gy cm 2 for 10 to <16 yr, respectively. The third quartile value obtained for the DAP/body weight ratio for the full sample of procedures was 0.17 (Gy cm 2 /kg) for diagnostic and therapeutic procedures. Conclusions: The data presented in this paper are an initial attempt at establishing local DRLs in pediatric interventional cardiology, from a large sample of procedures for the standard age bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there may be large differences

  7. Commentary Variations: Level of Verbalization, Personal Reference, and Phase Relations in Instructional Films on Perceptual-Motor Tasks. Technical Report.

    Science.gov (United States)

    Zuckerman, John V.

    In an experiment to determine the most efficient design for the commentary of an instructional film, special consideration was given to three variables concerned with the construction of commentaries: the level of verbalization (the amount of talk), the personal reference of the narrator, and the phase relationship between the commentary and the…

  8. Annual limits on intake for members of the public and derived reference levels of radionuclide concentrations in the environment

    International Nuclear Information System (INIS)

    Mason, G.C.

    1983-01-01

    A proposal is presented recommending the introduction in Australia of Annual Limits on Intake of radionuclides for members of the public and of corresponding reference levels of radionuclide concentrations in the environment. The proposal is related to recent recommendations of the International Commission on Radiological Protection and draft recommendations under consideration by the International Atomic Energy Agency

  9. Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: Theoretical assessment of the induced peak temperature increase

    NARCIS (Netherlands)

    J. Bakker (Jan); M.M. Paulides (Maarten); E. Neufeld; A. Christ (A.); N. Kuster (Niels); G.C. van Rhoon (Gerard)

    2011-01-01

    textabstractTo avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR wb) are provided to keep the

  10. A combined single-multiphase flow formulation of the premixing phase using the level set method

    International Nuclear Information System (INIS)

    Leskovar, M.; Marn, J.

    1999-01-01

    The premixing phase of a steam explosion covers the interaction of the melt jet or droplets with the water prior to any steam explosion occurring. To get a better insight of the hydrodynamic processes during the premixing phase beside hot premixing experiments, where the water evaporation is significant, also cold isothermal premixing experiments are performed. The specialty of isothermal premixing experiments is that three phases are involved: the water, the air and the spheres phase, but only the spheres phase mixes with the other two phases whereas the water and air phases do not mix and remain separated by a free surface. Our idea therefore was to treat the isothermal premixing process with a combined single-multiphase flow model. In this combined model the water and air phase are treated as a single phase with discontinuous phase properties at the water air interface, whereas the spheres are treated as usually with a multiphase flow model, where the spheres represent the dispersed phase and the common water-air phase represents the continuous phase. The common water-air phase was described with the front capturing method based on the level set formulation. In the level set formulation, the boundary of two-fluid interfaces is modeled as the zero set of a smooth signed normal distance function defined on the entire physical domain. The boundary is then updated by solving a nonlinear equation of the Hamilton-Jacobi type on the whole domain. With this single-multiphase flow model the Queos isothermal premixing Q08 has been simulated. A numerical analysis using different treatments of the water-air interface (level set, high-resolution and upwind) has been performed for the incompressible and compressible case and the results were compared to experimental measurements.(author)

  11. A Physical Activity Reference Data-Set Recorded from Older Adults Using Body-Worn Inertial Sensors and Video Technology—The ADAPT Study Data-Set

    Directory of Open Access Journals (Sweden)

    Alan Kevin Bourke

    2017-03-01

    Full Text Available Physical activity monitoring algorithms are often developed using conditions that do not represent real-life activities, not developed using the target population, or not labelled to a high enough resolution to capture the true detail of human movement. We have designed a semi-structured supervised laboratory-based activity protocol and an unsupervised free-living activity protocol and recorded 20 older adults performing both protocols while wearing up to 12 body-worn sensors. Subjects’ movements were recorded using synchronised cameras (≥25 fps, both deployed in a laboratory environment to capture the in-lab portion of the protocol and a body-worn camera for out-of-lab activities. Video labelling of the subjects’ movements was performed by five raters using 11 different category labels. The overall level of agreement was high (percentage of agreement >90.05%, and Cohen’s Kappa, corrected kappa, Krippendorff’s alpha and Fleiss’ kappa >0.86. A total of 43.92 h of activities were recorded, including 9.52 h of in-lab and 34.41 h of out-of-lab activities. A total of 88.37% and 152.01% of planned transitions were recorded during the in-lab and out-of-lab scenarios, respectively. This study has produced the most detailed dataset to date of inertial sensor data, synchronised with high frame-rate (≥25 fps video labelled data recorded in a free-living environment from older adults living independently. This dataset is suitable for validation of existing activity classification systems and development of new activity classification algorithms.

  12. Improved inhalation technology for setting safe exposure levels for workplace chemicals

    Science.gov (United States)

    Stuart, Bruce O.

    1993-01-01

    Threshold Limit Values recommended as allowable air concentrations of a chemical in the workplace are often based upon a no-observable-effect-level (NOEL) determined by experimental inhalation studies using rodents. A 'safe level' for human exposure must then be estimated by the use of generalized safety factors in attempts to extrapolate from experimental rodents to man. The recent development of chemical-specific physiologically-based toxicokinetics makes use of measured physiological, biochemical, and metabolic parameters to construct a validated model that is able to 'scale-up' rodent response data to predict the behavior of the chemical in man. This procedure is made possible by recent advances in personal computer software and the emergence of appropriate biological data, and provides an analytical tool for much more reliable risk evaluation and airborne chemical exposure level setting for humans.

  13. Setting ozone critical levels for protecting horticultural Mediterranean crops: Case study of tomato

    International Nuclear Information System (INIS)

    González-Fernández, I.; Calvo, E.; Gerosa, G.; Bermejo, V.; Marzuoli, R.; Calatayud, V.; Alonso, R.

    2014-01-01

    Seven experiments carried out in Italy and Spain have been used to parameterising a stomatal conductance model and establishing exposure– and dose–response relationships for yield and quality of tomato with the main goal of setting O 3 critical levels (CLe). CLe with confidence intervals, between brackets, were set at an accumulated hourly O 3 exposure over 40 nl l −1 , AOT40 = 8.4 (1.2, 15.6) ppm h and a phytotoxic ozone dose above a threshold of 6 nmol m −2 s −1 , POD6 = 2.7 (0.8, 4.6) mmol m −2 for yield and AOT40 = 18.7 (8.5, 28.8) ppm h and POD6 = 4.1 (2.0, 6.2) mmol m −2 for quality, both indices performing equally well. CLe confidence intervals provide information on the quality of the dataset and should be included in future calculations of O 3 CLe for improving current methodologies. These CLe, derived for sensitive tomato cultivars, should not be applied for quantifying O 3 -induced losses at the risk of making important overestimations of the economical losses associated with O 3 pollution. -- Highlights: • Seven independent experiments from Italy and Spain were analysed. • O 3 critical levels are proposed for the protection of summer horticultural crops. • Exposure- and flux-based O 3 indices performed equally well. • Confidence intervals of the new O 3 critical levels are calculated. • A new method to estimate the degree risk of O 3 damage is proposed. -- Critical levels for tomato yield were set at AOT40 = 8.4 ppm h and POD6 = 2.7 mmol m −2 and confidence intervals should be used for improving O 3 risk assessment

  14. Numerical Modelling of Three-Fluid Flow Using The Level-set Method

    Science.gov (United States)

    Li, Hongying; Lou, Jing; Shang, Zhi

    2014-11-01

    This work presents a numerical model for simulation of three-fluid flow involving two different moving interfaces. These interfaces are captured using the level-set method via two different level-set functions. A combined formulation with only one set of conservation equations for the whole physical domain, consisting of the three different immiscible fluids, is employed. Numerical solution is performed on a fixed mesh using the finite volume method. Surface tension effect is incorporated using the Continuum Surface Force model. Validation of the present model is made against available results for stratified flow and rising bubble in a container with a free surface. Applications of the present model are demonstrated by a variety of three-fluid flow systems including (1) three-fluid stratified flow, (2) two-fluid stratified flow carrying the third fluid in the form of drops and (3) simultaneous rising and settling of two drops in a stationary third fluid. The work is supported by a Thematic and Strategic Research from A*STAR, Singapore (Ref. #: 1021640075).

  15. Parallel implementation of multireference coupled-cluster theories based on the reference-level parallelism

    Energy Technology Data Exchange (ETDEWEB)

    Brabec, Jiri; Pittner, Jiri; van Dam, Hubertus JJ; Apra, Edoardo; Kowalski, Karol

    2012-02-01

    A novel algorithm for implementing general type of multireference coupled-cluster (MRCC) theory based on the Jeziorski-Monkhorst exponential Ansatz [B. Jeziorski, H.J. Monkhorst, Phys. Rev. A 24, 1668 (1981)] is introduced. The proposed algorithm utilizes processor groups to calculate the equations for the MRCC amplitudes. In the basic formulation each processor group constructs the equations related to a specific subset of references. By flexible choice of processor groups and subset of reference-specific sufficiency conditions designated to a given group one can assure optimum utilization of available computing resources. The performance of this algorithm is illustrated on the examples of the Brillouin-Wigner and Mukherjee MRCC methods with singles and doubles (BW-MRCCSD and Mk-MRCCSD). A significant improvement in scalability and in reduction of time to solution is reported with respect to recently reported parallel implementation of the BW-MRCCSD formalism [J.Brabec, H.J.J. van Dam, K. Kowalski, J. Pittner, Chem. Phys. Lett. 514, 347 (2011)].

  16. Nurses' comfort level with spiritual assessment: a study among nurses working in diverse healthcare settings.

    Science.gov (United States)

    Cone, Pamela H; Giske, Tove

    2017-10-01

    To gain knowledge about nurses' comfort level in assessing spiritual matters and to learn what questions nurses use in practice related to spiritual assessment. Spirituality is important in holistic nursing care; however, nurses report feeling uncomfortable and ill-prepared to address this domain with patients. Education is reported to impact nurses' ability to engage in spiritual care. This cross-sectional exploratory survey reports on a mixed-method study examining how comfortable nurses are with spiritual assessment. In 2014, a 21-item survey with 10 demographic variables and three open-ended questions were distributed to Norwegian nurses working in diverse care settings with 172 nurse responses (72 % response rate). SPSS was used to analyse quantitative data; thematic analysis examined the open-ended questions. Norwegian nurses reported a high level of comfort with most questions even though spirituality is seen as private. Nurses with some preparation or experience in spiritual care were most comfortable assessing spirituality. Statistically significant correlations were found between the nurses' comfort level with spiritual assessment and their preparedness and sense of the importance of spiritual assessment. How well-prepared nurses felt was related to years of experience, degree of spirituality and religiosity, and importance of spiritual assessment. Many nurses are poorly prepared for spiritual assessment and care among patients in diverse care settings; educational preparation increases their comfort level with facilitating such care. Nurses who feel well prepared with spirituality feel more comfortable with the spiritual domain. By fostering a culture where patients' spirituality is discussed and reflected upon in everyday practice and in continued education, nurses' sense of preparedness, and thus their level of comfort, can increase. Clinical supervision and interprofessional collaboration with hospital chaplains and/or other spiritual leaders can

  17. Segmentation of teeth in CT volumetric dataset by panoramic projection and variational level set

    International Nuclear Information System (INIS)

    Hosntalab, Mohammad; Aghaeizadeh Zoroofi, Reza; Abbaspour Tehrani-Fard, Ali; Shirani, Gholamreza

    2008-01-01

    Quantification of teeth is of clinical importance for various computer assisted procedures such as dental implant, orthodontic planning, face, jaw and cosmetic surgeries. In this regard, segmentation is a major step. In this paper, we propose a method for segmentation of teeth in volumetric computed tomography (CT) data using panoramic re-sampling of the dataset in the coronal view and variational level set. The proposed method consists of five steps as follows: first, we extract a mask in a CT images using Otsu thresholding. Second, the teeth are segmented from other bony tissues by utilizing anatomical knowledge of teeth in the jaws. Third, the proposed method is followed by estimating the arc of the upper and lower jaws and panoramic re-sampling of the dataset. Separation of upper and lower jaws and initial segmentation of teeth are performed by employing the horizontal and vertical projections of the panoramic dataset, respectively. Based the above mentioned procedures an initial mask for each tooth is obtained. Finally, we utilize the initial mask of teeth and apply a Variational level set to refine initial teeth boundaries to final contours. The proposed algorithm was evaluated in the presence of 30 multi-slice CT datasets including 3,600 images. Experimental results reveal the effectiveness of the proposed method. In the proposed algorithm, the variational level set technique was utilized to trace the contour of the teeth. In view of the fact that, this technique is based on the characteristic of the overall region of the teeth image, it is possible to extract a very smooth and accurate tooth contour using this technique. In the presence of the available datasets, the proposed technique was successful in teeth segmentation compared to previous techniques. (orig.)

  18. Segmentation of teeth in CT volumetric dataset by panoramic projection and variational level set

    Energy Technology Data Exchange (ETDEWEB)

    Hosntalab, Mohammad [Islamic Azad University, Faculty of Engineering, Science and Research Branch, Tehran (Iran); Aghaeizadeh Zoroofi, Reza [University of Tehran, Control and Intelligent Processing Center of Excellence, School of Electrical and Computer Engineering, College of Engineering, Tehran (Iran); Abbaspour Tehrani-Fard, Ali [Islamic Azad University, Faculty of Engineering, Science and Research Branch, Tehran (Iran); Sharif University of Technology, Department of Electrical Engineering, Tehran (Iran); Shirani, Gholamreza [Faculty of Dentistry Medical Science of Tehran University, Oral and Maxillofacial Surgery Department, Tehran (Iran)

    2008-09-15

    Quantification of teeth is of clinical importance for various computer assisted procedures such as dental implant, orthodontic planning, face, jaw and cosmetic surgeries. In this regard, segmentation is a major step. In this paper, we propose a method for segmentation of teeth in volumetric computed tomography (CT) data using panoramic re-sampling of the dataset in the coronal view and variational level set. The proposed method consists of five steps as follows: first, we extract a mask in a CT images using Otsu thresholding. Second, the teeth are segmented from other bony tissues by utilizing anatomical knowledge of teeth in the jaws. Third, the proposed method is followed by estimating the arc of the upper and lower jaws and panoramic re-sampling of the dataset. Separation of upper and lower jaws and initial segmentation of teeth are performed by employing the horizontal and vertical projections of the panoramic dataset, respectively. Based the above mentioned procedures an initial mask for each tooth is obtained. Finally, we utilize the initial mask of teeth and apply a Variational level set to refine initial teeth boundaries to final contours. The proposed algorithm was evaluated in the presence of 30 multi-slice CT datasets including 3,600 images. Experimental results reveal the effectiveness of the proposed method. In the proposed algorithm, the variational level set technique was utilized to trace the contour of the teeth. In view of the fact that, this technique is based on the characteristic of the overall region of the teeth image, it is possible to extract a very smooth and accurate tooth contour using this technique. In the presence of the available datasets, the proposed technique was successful in teeth segmentation compared to previous techniques. (orig.)

  19. The IAEA Biomass programme: reference biospheres for long-term safety assessment of high level waste disposal facilities

    International Nuclear Information System (INIS)

    Metcalf, Phil; Crossland, Ian; Torres, Carlos; Crossland, Ian J.

    2002-01-01

    Phil Metcalf and Ian Crossland presented the IAEA Biomass project. Phil Metcalf explained that the Biomass project, begun in 1996, by an international forum organised by the IAEA was a very good exercise for exchanging information through technical meetings and documentation such as Biomass newsletters or CD Rom. Ian Crossland continued by giving a presentation of the Biomass theme 1 that concerns the radioactive waste disposal topic. Its objective was mainly to develop the reference biosphere methodology and to demonstrate its usefulness through some exercises related to the development of a practical set of example biospheres such as: 1. drinking water well, 2. agricultural irrigation, with a well source and 3. Set of natural groundwater discharges to natural, semi-natural systems. Input data would always change to accommodate a given repository simulation and location. Thus this project must be seen as a good exercise for the application of a methodology and should be considered as a good source of reference biospheres that might be viewed as a benchmark for comparison with site-specific safety assessments for a selected number of radionuclides. The main conclusion from the Biomass theme 1 project was that there appears to be an international consensus on preparing generic reference biospheres for postclosure safety assessment but waste management organisations should also consider the specific requirements of regulators and other stakeholders

  20. Level Set-Based Topology Optimization for the Design of an Electromagnetic Cloak With Ferrite Material

    DEFF Research Database (Denmark)

    Otomori, Masaki; Yamada, Takayuki; Andkjær, Jacob Anders

    2013-01-01

    . A level set-based topology optimization method incorporating a fictitious interface energy is used to find optimized configurations of the ferrite material. The numerical results demonstrate that the optimization successfully found an appropriate ferrite configuration that functions as an electromagnetic......This paper presents a structural optimization method for the design of an electromagnetic cloak made of ferrite material. Ferrite materials exhibit a frequency-dependent degree of permeability, due to a magnetic resonance phenomenon that can be altered by changing the magnitude of an externally...

  1. A multilevel, level-set method for optimizing eigenvalues in shape design problems

    International Nuclear Information System (INIS)

    Haber, E.

    2004-01-01

    In this paper, we consider optimal design problems that involve shape optimization. The goal is to determine the shape of a certain structure such that it is either as rigid or as soft as possible. To achieve this goal we combine two new ideas for an efficient solution of the problem. First, we replace the eigenvalue problem with an approximation by using inverse iteration. Second, we use a level set method but rather than propagating the front we use constrained optimization methods combined with multilevel continuation techniques. Combining these two ideas we obtain a robust and rapid method for the solution of the optimal design problem

  2. Modeling Restrained Shrinkage Induced Cracking in Concrete Rings Using the Thick Level Set Approach

    Directory of Open Access Journals (Sweden)

    Rebecca Nakhoul

    2018-03-01

    Full Text Available Modeling restrained shrinkage-induced damage and cracking in concrete is addressed herein. The novel Thick Level Set (TLS damage growth and crack propagation model is used and adapted by introducing shrinkage contribution into the formulation. The TLS capacity to predict damage evolution, crack initiation and growth triggered by restrained shrinkage in absence of external loads is evaluated. A study dealing with shrinkage-induced cracking in elliptical concrete rings is presented herein. Key results such as the effect of rings oblateness on stress distribution and critical shrinkage strain needed to initiate damage are highlighted. In addition, crack positions are compared to those observed in experiments and are found satisfactory.

  3. Microwave imaging of dielectric cylinder using level set method and conjugate gradient algorithm

    International Nuclear Information System (INIS)

    Grayaa, K.; Bouzidi, A.; Aguili, T.

    2011-01-01

    In this paper, we propose a computational method for microwave imaging cylinder and dielectric object, based on combining level set technique and the conjugate gradient algorithm. By measuring the scattered field, we tried to retrieve the shape, localisation and the permittivity of the object. The forward problem is solved by the moment method, while the inverse problem is reformulate in an optimization one and is solved by the proposed scheme. It found that the proposed method is able to give good reconstruction quality in terms of the reconstructed shape and permittivity.

  4. The validity and reliability of value-added and target-setting procedures with special reference to Key Stage 3

    OpenAIRE

    Moody, Ian Robin

    2003-01-01

    The validity of value-added systems of measurement is crucially dependent upon there being a demonstrably unambiguous relationship between the so-called baseline, or intake measures, and any subsequent measure of performance at a later stage. The reliability of such procedures is dependent on the relationships between these two measures being relatively stable over time. A number of questions arise with regard to both the validity and reliability of value-added procedures at any level in educ...

  5. Research on maximum level noise contaminated of remote reference magnetotelluric measurements using synthesized data

    Science.gov (United States)

    Gang, Zhang; Fansong, Meng; Jianzhong, Wang; Mingtao, Ding

    2018-02-01

    Determining magnetotelluric impedance precisely and accurately is fundamental to valid inversion and geological interpretation. This study aims to determine the minimum value of signal-to-noise ratio (SNR) which maintains the effectiveness of remote reference technique. Results of standard time series simulation, addition of different Gaussian noises to obtain the different SNR time series, and analysis of the intermediate data, such as polarization direction, correlation coefficient, and impedance tensor, show that when the SNR value is larger than 23.5743, the polarization direction disorder at morphology and a smooth and accurate sounding carve value can be obtained. At this condition, the correlation coefficient value of nearly complete segments between the base and remote station is larger than 0.9, and impedance tensor Zxy presents only one aggregation, which meet the natural magnetotelluric signal characteristic.

  6. Determination of diagnostic reference levels in general radiography in Latin America

    International Nuclear Information System (INIS)

    Blanco, S.; Mora, P.; Almonte, N.; Benavente, T.; Benson, N.; Blanco, D.; Cardenas, J.; Gomez, Y. D.; Edding, O.; Escobar, C.; Fonseca, M.; Gamarra, M.; Aguilar, J. G.; Khoury, H. J.; Quintero, A. R.; Zuniga, N. R.; Zaire, E.; Nader, A.

    2013-01-01

    The International Atomic Energy Agency (IAEA) through the International Action Plan on Radiation Protection of Patients and the International Commission on Radiological Protection have for some time carried out important efforts to assure that in the medical applications of the ionising radiations, the optimisation of radiological protection of patients is fundamental, to such a point that the IAEA includes it directly as a requirement for these practices (in its International Basic Safety Standards for Protection against Ionising Radiation and for the Safety of Radiation Sources (BSS)-GSR Part 1, 2011). For this reason, among the objectives of Regional Project RLA/9/057 and Regional Project RLA/9/067, the intention was to establish the dose references in conventional radiology for Latin America, for the purposes of determining whether these doses comply with the requirements of the BSS and to tend to improve practices, in order to minimise the dose received by the patients. (authors)

  7. Adrenal Vein Catecholamine Levels and Ratios: Reference Intervals Derived from Patients with Primary Aldosteronism.

    Science.gov (United States)

    Sze, Candy W C; O'Toole, Samuel Matthew; Tirador, Roger Kent; Akker, Scott A; Matson, Matthew; Perry, Leslie; Druce, Maralyn Rose; Dekkers, Tanja; Deinum, Jaap; Lenders, Jacques W M; Eisenhofer, Graeme; Drake, William Martyn

    2017-06-01

    Phaeochromocytoma localisation is generally reliably achieved with modern imaging techniques, particularly in sporadic cases. On occasion, however, there can be diagnostic doubt due to the presence of bilateral adrenal abnormalities, particularly in patients with mutations in genes predisposing them to the development of multiple phaeochromocytomas. In such cases, surgical intervention is ideally limited to large or functional lesions due to the long-term consequences associated with hypoadrenalism. Adrenal venous sampling (AVS) for catecholamines has been used in this situation to guide surgery, although there are few data available to support diagnostic thresholds. Retrospective analyses of AVS results from 2 centres were carried out. A total of 172 patients (88 men, 84 women) underwent AVS under cosyntropin stimulation for the diagnosis of established primary aldosteronism (PA) with measurement of adrenal and peripheral venous cortisol, aldosterone and catecholamines. Six patients (3 men, 3 women) with phaeochromocytoma underwent AVS for diagnostic purposes with subsequent histological confirmation. Reference intervals for the adrenal venous norepinephrine to epinephrine ratio were created from the PA group. Using the 97.5th centile (1.21 on the left, 1.04 on the right), the false negative rate in the phaeochromocytoma group was 0%. In conclusion, this study describes the largest dataset of adrenal venous catecholamine measurements and provides reference intervals in patients without phaeochromocytoma. This strengthens the certainty with which conclusions related to adrenal venous sampling for catecholamines can be drawn, acknowledging the procedure is not part of the routine diagnostic workup and is an adjunct for use only in difficult clinical cases. © Georg Thieme Verlag KG Stuttgart · New York.

  8. A Variational Level Set Approach Based on Local Entropy for Image Segmentation and Bias Field Correction.

    Science.gov (United States)

    Tang, Jian; Jiang, Xiaoliang

    2017-01-01

    Image segmentation has always been a considerable challenge in image analysis and understanding due to the intensity inhomogeneity, which is also commonly known as bias field. In this paper, we present a novel region-based approach based on local entropy for segmenting images and estimating the bias field simultaneously. Firstly, a local Gaussian distribution fitting (LGDF) energy function is defined as a weighted energy integral, where the weight is local entropy derived from a grey level distribution of local image. The means of this objective function have a multiplicative factor that estimates the bias field in the transformed domain. Then, the bias field prior is fully used. Therefore, our model can estimate the bias field more accurately. Finally, minimization of this energy function with a level set regularization term, image segmentation, and bias field estimation can be achieved. Experiments on images of various modalities demonstrated the superior performance of the proposed method when compared with other state-of-the-art approaches.

  9. Implications of sea-level rise in a modern carbonate ramp setting

    Science.gov (United States)

    Lokier, Stephen W.; Court, Wesley M.; Onuma, Takumi; Paul, Andreas

    2018-03-01

    This study addresses a gap in our understanding of the effects of sea-level rise on the sedimentary systems and morphological development of recent and ancient carbonate ramp settings. Many ancient carbonate sequences are interpreted as having been deposited in carbonate ramp settings. These settings are poorly-represented in the Recent. The study documents the present-day transgressive flooding of the Abu Dhabi coastline at the southern shoreline of the Arabian/Persian Gulf, a carbonate ramp depositional system that is widely employed as a Recent analogue for numerous ancient carbonate systems. Fourteen years of field-based observations are integrated with historical and recent high-resolution satellite imagery in order to document and assess the onset of flooding. Predicted rates of transgression (i.e. landward movement of the shoreline) of 2.5 m yr- 1 (± 0.2 m yr- 1) based on global sea-level rise alone were far exceeded by the flooding rate calculated from the back-stepping of coastal features (10-29 m yr- 1). This discrepancy results from the dynamic nature of the flooding with increased water depth exposing the coastline to increased erosion and, thereby, enhancing back-stepping. A non-accretionary transgressive shoreline trajectory results from relatively rapid sea-level rise coupled with a low-angle ramp geometry and a paucity of sediments. The flooding is represented by the landward migration of facies belts, a range of erosive features and the onset of bioturbation. Employing Intergovernmental Panel on Climate Change (Church et al., 2013) predictions for 21st century sea-level rise, and allowing for the post-flooding lag time that is typical for the start-up of carbonate factories, it is calculated that the coastline will continue to retrograde for the foreseeable future. Total passive flooding (without considering feedback in the modification of the shoreline) by the year 2100 is calculated to likely be between 340 and 571 m with a flooding rate of 3

  10. [Medical safety management in the setting of a clinical reference laboratory--risk management efforts in clinical testing].

    Science.gov (United States)

    Seki, Akira; Miya, Tetsumasa

    2011-03-01

    As a result of recurring medical accidents, risk management in the medical setting has been given much attention. The announcement in August, 2000 by the Ministry of Health committee for formulating a standard manual for risk management, of a "Risk management manual formulation guideline" has since been accompanied by the efforts of numerous medical testing facilities to develop such documents. In 2008, ISO/TS 22367:2008 on "Medical laboratories-Reduction of error through risk management and continual improvement" was published. However, at present, risk management within a medical testing facility stresses the implementation of provisional actions in response to a problem after it has occurred. Risk management is basically a planned process and includes "corrective actions" as well as "preventive actions." A corrective action is defined as identifying the root cause of the problem and removing it, and is conducted to prevent the problem from recurring. A preventive action is defined as identifying of the any potential problem and removing it, and is conducted to prevent a problem before it occurs. Presently, I shall report on the experiences of our laboratory regarding corrective and preventive actions taken in response to accidents and incidents, respectively.

  11. Robust space-time extraction of ventricular surface evolution using multiphase level sets

    Science.gov (United States)

    Drapaca, Corina S.; Cardenas, Valerie; Studholme, Colin

    2004-05-01

    This paper focuses on the problem of accurately extracting the CSF-tissue boundary, particularly around the ventricular surface, from serial structural MRI of the brain acquired in imaging studies of aging and dementia. This is a challenging problem because of the common occurrence of peri-ventricular lesions which locally alter the appearance of white matter. We examine a level set approach which evolves a four dimensional description of the ventricular surface over time. This has the advantage of allowing constraints on the contour in the temporal dimension, improving the consistency of the extracted object over time. We follow the approach proposed by Chan and Vese which is based on the Mumford and Shah model and implemented using the Osher and Sethian level set method. We have extended this to the 4 dimensional case to propagate a 4D contour toward the tissue boundaries through the evolution of a 5D implicit function. For convergence we use region-based information provided by the image rather than the gradient of the image. This is adapted to allow intensity contrast changes between time frames in the MRI sequence. Results on time sequences of 3D brain MR images are presented and discussed.

  12. An improved level set method for brain MR images segmentation and bias correction.

    Science.gov (United States)

    Chen, Yunjie; Zhang, Jianwei; Macione, Jim

    2009-10-01

    Intensity inhomogeneities cause considerable difficulty in the quantitative analysis of magnetic resonance (MR) images. Thus, bias field estimation is a necessary step before quantitative analysis of MR data can be undertaken. This paper presents a variational level set approach to bias correction and segmentation for images with intensity inhomogeneities. Our method is based on an observation that intensities in a relatively small local region are separable, despite of the inseparability of the intensities in the whole image caused by the overall intensity inhomogeneity. We first define a localized K-means-type clustering objective function for image intensities in a neighborhood around each point. The cluster centers in this objective function have a multiplicative factor that estimates the bias within the neighborhood. The objective function is then integrated over the entire domain to define the data term into the level set framework. Our method is able to capture bias of quite general profiles. Moreover, it is robust to initialization, and thereby allows fully automated applications. The proposed method has been used for images of various modalities with promising results.

  13. Topology optimization in acoustics and elasto-acoustics via a level-set method

    Science.gov (United States)

    Desai, J.; Faure, A.; Michailidis, G.; Parry, G.; Estevez, R.

    2018-04-01

    Optimizing the shape and topology (S&T) of structures to improve their acoustic performance is quite challenging. The exact position of the structural boundary is usually of critical importance, which dictates the use of geometric methods for topology optimization instead of standard density approaches. The goal of the present work is to investigate different possibilities for handling topology optimization problems in acoustics and elasto-acoustics via a level-set method. From a theoretical point of view, we detail two equivalent ways to perform the derivation of surface-dependent terms and propose a smoothing technique for treating problems of boundary conditions optimization. In the numerical part, we examine the importance of the surface-dependent term in the shape derivative, neglected in previous studies found in the literature, on the optimal designs. Moreover, we test different mesh adaptation choices, as well as technical details related to the implicit surface definition in the level-set approach. We present results in two and three-space dimensions.

  14. A mass conserving level set method for detailed numerical simulation of liquid atomization

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Kun; Shao, Changxiao [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China); Yang, Yue [State Key Laboratory of Turbulence and Complex Systems, Peking University, Beijing 100871 (China); Fan, Jianren, E-mail: fanjr@zju.edu.cn [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China)

    2015-10-01

    An improved mass conserving level set method for detailed numerical simulations of liquid atomization is developed to address the issue of mass loss in the existing level set method. This method introduces a mass remedy procedure based on the local curvature at the interface, and in principle, can ensure the absolute mass conservation of the liquid phase in the computational domain. Three benchmark cases, including Zalesak's disk, a drop deforming in a vortex field, and the binary drop head-on collision, are simulated to validate the present method, and the excellent agreement with exact solutions or experimental results is achieved. It is shown that the present method is able to capture the complex interface with second-order accuracy and negligible additional computational cost. The present method is then applied to study more complex flows, such as a drop impacting on a liquid film and the swirling liquid sheet atomization, which again, demonstrates the advantages of mass conservation and the capability to represent the interface accurately.

  15. On the Relationship between Variational Level Set-Based and SOM-Based Active Contours

    Science.gov (United States)

    Abdelsamea, Mohammed M.; Gnecco, Giorgio; Gaber, Mohamed Medhat; Elyan, Eyad

    2015-01-01

    Most Active Contour Models (ACMs) deal with the image segmentation problem as a functional optimization problem, as they work on dividing an image into several regions by optimizing a suitable functional. Among ACMs, variational level set methods have been used to build an active contour with the aim of modeling arbitrarily complex shapes. Moreover, they can handle also topological changes of the contours. Self-Organizing Maps (SOMs) have attracted the attention of many computer vision scientists, particularly in modeling an active contour based on the idea of utilizing the prototypes (weights) of a SOM to control the evolution of the contour. SOM-based models have been proposed in general with the aim of exploiting the specific ability of SOMs to learn the edge-map information via their topology preservation property and overcoming some drawbacks of other ACMs, such as trapping into local minima of the image energy functional to be minimized in such models. In this survey, we illustrate the main concepts of variational level set-based ACMs, SOM-based ACMs, and their relationship and review in a comprehensive fashion the development of their state-of-the-art models from a machine learning perspective, with a focus on their strengths and weaknesses. PMID:25960736

  16. Application of acid whey and set milk to marinate beef with reference to quality parameters and product safety.

    Science.gov (United States)

    Wójciak, Karolina M; Krajmas, Paweł; Solska, Elżbieta; Dolatowski, Zbigniew J

    2015-01-01

    The aim of the study was to evaluate the potential of acid whey and set milk as a marinade in the traditional production of fermented eye round. Studies involved assaying pH value, water activity (aw), oxidation-reduction potential and TBARS value, colour parameters in CIE system (L*, a*, b*), assaying the number of lactic acid bacteria and certain pathogenic bacteria after ripening process and after 60-day storing in cold storage. Sensory analysis and analysis of the fatty acids profile were performed after completion of the ripening process. Analysis of pH value in the products revealed that application of acid whey to marinate beef resulted in increased acidity of ripening eye round (5.14). The highest value of the colour parameter a* after ripening process and during storage was observed in sample AW (12.76 and 10.07 respectively), the lowest on the other hand was observed in sample SM (10.06 and 7.88 respectively). The content of polyunsaturated fatty acids (PUFA) was higher in eye round marinated in acid whey by approx. 4% in comparison to other samples. Application of acid whey to marinade beef resulted in increased share of red colour in general colour tone as well as increased oxidative stability of the product during storage. It also increased the content of polyunsaturated fatty acids (PUFA) in the product. All model products had high content of lactic acid bacteria and there were no pathogenic bacteria such as: L. monocytogenes, Y. enterocolitica, S. aureus, Clostridium sp.

  17. Reference range levels of polycyclic aromatic hydrocarbons in the US population by measurement of urinary monohydroxy metabolites

    International Nuclear Information System (INIS)

    Grainger, James; Huang, Wenlin; Patterson, Donald G.; Turner, Wayman E.; Pirkle, James; Caudill, Samuel P.; Wang, Richard Y.; Needham, Larry L.; Sampson, Eric J.

    2006-01-01

    We developed a gas chromatography isotope-dilution high-resolution mass spectrometry (GC/Id-HRMS) method for measuring 14 polycyclic aromatic hydrocarbon (PAH) metabolites representing seven parent PAHs in 3 mL of urine at low parts-per-trillion levels. PAH levels were determined in urine samples collected in 1999 and 2000 from approximately 2400 participants in the National Health and Nutrition Examination Survey, and, for the first time, reference range values were calculated for these metabolites in the US population. Using this GC/ID-HRMS method, we found detectable concentrations for monohydroxy metabolite isomers of fluorene, phenanthrene, fluoranthene, pyrene, and chrysene, benzo[c]phenanthrene, and benz[a]anthracene. Some monohydroxy metabolite isomers of benzo[c]phenanthrene, chrysene, and benz[a]anthracene exhibited low detection frequencies that did not allow for geometric mean calculations. Our study results enabled us to establish a reference range for the targeted PAHs in the general US population

  18. Speakeasy-3 reference manual. Level MU. IBM OS/VS version

    International Nuclear Information System (INIS)

    Cohen, S.; Pieper, S.C.

    1977-08-01

    Speakeasy is a computer language designed to provide access to information stored in a computer. Ease of use, natural notation, and built-in capabilities for growth are important features of Speakeasy. The language is based on the concepts of arrays and matrices, and processes these as entities; the need for many of the loops necessary in other programing languages is thus eliminated. It has a large vocabulary (over 500 words) of functions and commands in the areas of array manipulation, matrix algebra including eigenanalysis, special mathematical functions, numerical integration and differentiation, statistics, graphics, and character processing. It can be used either in batch mode or interactively. This book is the primary reference manual for the Speakeasy language and presents a nearly complete description of its capabilities. The chapters deal with the use of Speakeasy as a ''super desk calculator,'' the construction and editing of Speakeasy programs, the ability to communicate with other programing languages, the construction of user-written additions to the language, and various other facets of Speakeasy. In addition, a complete listing of the Help Library, which contains brief descriptions of each of the Speakeasy functions or commands, is included. This edition applies to the Mu release of Speakeasy-3, and describes the IBM OS/VS version. 18 figures

  19. Safety Study of the X-Ray Reference Laboratory for Radiation Protection Levels (IR-14D)

    International Nuclear Information System (INIS)

    Garcia, G.

    1999-01-01

    This report is a study about the safety of the X-ray reference laboratory that has been recently constructed in the building 2 of the CIEMAT. After a brief description of the apparatus, we present the method used to calculate the exposure and absorbed dose rates in the most characteristic points of the laboratory. This method takes into account the spectral distribution of the radiation beams as a function of the accelerating voltage. The built-up factors of the absorbent materials have been considered to calculate the transmission of the radiation beams through the filters and shielding. Scattered radiations has been introduced in the calculations by means of a semiempirical method. This model supposes that multiple scattering processes give an isotropic contribution to the reflected beams and the single scattered can be described in terms of the differential cross section of Klein-Nishina. The results of this study have been applied to determine the maximum dose equivalent that the personnel of the laboratory could receive in normal operation conditions. (Author) 5 refs

  20. HPC in Basin Modeling: Simulating Mechanical Compaction through Vertical Effective Stress using Level Sets

    Science.gov (United States)

    McGovern, S.; Kollet, S. J.; Buerger, C. M.; Schwede, R. L.; Podlaha, O. G.

    2017-12-01

    In the context of sedimentary basins, we present a model for the simulation of the movement of ageological formation (layers) during the evolution of the basin through sedimentation and compactionprocesses. Assuming a single phase saturated porous medium for the sedimentary layers, the modelfocuses on the tracking of the layer interfaces, through the use of the level set method, as sedimentationdrives fluid-flow and reduction of pore space by compaction. On the assumption of Terzaghi's effectivestress concept, the coupling of the pore fluid pressure to the motion of interfaces in 1-D is presented inMcGovern, et.al (2017) [1] .The current work extends the spatial domain to 3-D, though we maintain the assumption ofvertical effective stress to drive the compaction. The idealized geological evolution is conceptualized asthe motion of interfaces between rock layers, whose paths are determined by the magnitude of a speedfunction in the direction normal to the evolving layer interface. The speeds normal to the interface aredependent on the change in porosity, determined through an effective stress-based compaction law,such as the exponential Athy's law. Provided with the speeds normal to the interface, the level setmethod uses an advection equation to evolve a potential function, whose zero level set defines theinterface. Thus, the moving layer geometry influences the pore pressure distribution which couplesback to the interface speeds. The flexible construction of the speed function allows extension, in thefuture, to other terms to represent different physical processes, analogous to how the compaction rulerepresents material deformation.The 3-D model is implemented using the generic finite element method framework Deal II,which provides tools, building on p4est and interfacing to PETSc, for the massively parallel distributedsolution to the model equations [2]. Experiments are being run on the Juelich Supercomputing Center'sJureca cluster. [1] McGovern, et.al. (2017

  1. Educational level and risk of colorectal cancer in EPIC with specific reference to tumor location

    NARCIS (Netherlands)

    Leufkens, Anke M.; van Duijnhoven, Fränzel J. B.; Boshuizen, Hendriek C.; Siersema, Peter D.; Kunst, Anton E.; Mouw, Traci; Tjønneland, Anne; Olsen, Anja; Overvad, Kim; Boutron-Ruault, Marie-Christine; Clavel-Chapelon, Françoise; Morois, Sophie; Krogh, Vittorio; Tumino, Rosario; Panico, Salvatore; Polidoro, Silvia; Palli, Domenico; Kaaks, Rudolf; Teucher, Birgit; Pischon, Tobias; Trichopoulou, Antonia; Orfanos, Philippos; Goufa, Ioulia; Peeters, Petra H. M.; Skeie, Guri; Braaten, Tonje; Rodríguez, Laudina; Lujan-Barroso, Leila; Sánchez-Pérez, Maria-José; Navarro, Carmen; Barricarte, Aurelio; Zackrisson, Sophia; Almquist, Martin; Hallmans, Goran; Palmqvist, Richard; Tsilidis, Konstantinos K.; Khaw, Kay-Tee; Wareham, Nick; Gallo, Valentina; Jenab, Mazda; Riboli, Elio; Bueno-de-Mesquita, H. Bas

    2012-01-01

    Existing evidence is inconclusive on whether socioeconomic status (SES) and educational inequalities influence colorectal cancer (CRC) risk, and whether low or high SES/educational level is associated with developing CRC. The aim of our study was to investigate the relationship between educational

  2. The development of the first set of Brazilian reference materials for the petroleum sector; O desenvolvimento dos primeiros materiais de referencia nacionais para o setor de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Zucchini, Ricardo R. [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil). Agrupamento de Materiais de Referencia

    2004-07-01

    The petroleum sector uses a number of standardized tests to characterize raw materials and products. The development of in-company programs for assurance of measurement quality, the increasing need to demonstrate proficiency by means of certification schemes or by widely accepted metrological practices, have been promoting a more intensive use of certified reference materials, in calibration as well as in validation of measurement methods and also in order to show the qualification of the laboratories. In this paper it is presented the preparation, performed by IPT's Reference Materials Group, of the first set of reference materials specially developed considering the needs of the petroleum community. Briefly, are presented the identification of the demands from the users, selection of matrices, homogeneity tests and stability studies, and the certification of the new reference materials, which are four diesel fuel oils with certified sulfur contents and one material with flash point certified by TAG and Pensky-Martens methods. It is presented a summary of the certification process, performed by means of a combined effort of several professionals that are now working at laboratories of research institutions, refineries and other industries, universities, fuel monitoring facilities and in National Petroleum Agency. (author)

  3. Urbanist workshops between theory and practice: The importance of spatial and programme reference levels in the planning method

    OpenAIRE

    Gregor Čok

    2013-01-01

    One of the key characteristics of urban-architectural workshops as a soft planning method is above all the fact that the authors are free of burden of formal facts and reference levels of the local environment, which do not influence the concept and the working process. Within this framework, the workshop presents an opportunity for the creator to focus primarily on the core of the problem, and work creatively towards a substantiated professional solution. In addition to the basic ref...

  4. Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: theoretical assessment of the induced peak temperature increase

    Energy Technology Data Exchange (ETDEWEB)

    Bakker, J F; Paulides, M M; Van Rhoon, G C [Erasmus MC-Daniel den Hoed Cancer Center, Department of Radiation Oncology, Section Hyperthermia, PO Box 5201, NL-3008 AE, Rotterdam (Netherlands); Neufeld, E; Christ, A; Kuster, N, E-mail: j.bakker@erasmusmc.nl [Foundation for Research on Information Technologies in Society (IT' IS) (Switzerland)

    2011-08-07

    To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR{sub wb}) are provided to keep the whole-body temperature increase (T{sub body,incr}) under 1 deg. C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR{sub 10g}) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T{sub incr,max}) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T{sub incr,max} in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 deg. C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T{sub incr,max} as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T{sub incr,max} for specified durations of exposure.

  5. Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: theoretical assessment of the induced peak temperature increase.

    Science.gov (United States)

    Bakker, J F; Paulides, M M; Neufeld, E; Christ, A; Kuster, N; van Rhoon, G C

    2011-08-07

    To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR(wb)) are provided to keep the whole-body temperature increase (T(body, incr)) under 1 °C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR(10g)) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T(incr, max)) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T(incr, max) in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 °C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T(incr, max) as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T(incr, max) for specified durations of exposure.

  6. [Personalizing the reference level: gold standard to evaluate the quality of service perceived].

    Science.gov (United States)

    Rodrigo-Rincón, I; Reyes-Pérez, M; Martínez-Lozano, M E

    2014-01-01

    To know the cutoff point at which in-house Nuclear Medicine Department (MND) customers consider that the quality of service is good (personalized cutoff). We conducted a survey of the professionals who had requested at least 5 tests to the Nuclear Medicine Department. A total of 71 doctors responded (response rate: 30%). A question was added to the questionnaire for the user to establish a cutoff point for which they would consider the quality of service as good. The quality non-conformities, areas of improvement and strong points of the six questions measuring the quality of service (Likert scale 0 to 10) were compared with two different thresholds: personalized cutoff and one proposed by the service itself a priori. Test statistics: binomial and Student's t-test for paired data. A cutoff value of 7 was proposed by the service as a reference while 68.1% of respondents suggested a cutoff above 7 points (mean 7.9 points). The 6 elements of perceived quality were considered strong points with the cutoff proposed by the MND, while there were 3 detected with the personalized threshold. Thirteen percent of the answers were nonconformities with the service cutoff versus 19.2% with the personalized one, the differences being statistically significant (difference 95% CI 6.44%:0,83-12.06). The final image of the perceived quality of an in-house customer is different when using the cutoff established by the Department versus the personalized cutoff given by the respondent. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

  7. Two generators to produce SI-traceable reference gas mixtures for reactive compounds at atmospheric levels

    Science.gov (United States)

    Pascale, C.; Guillevic, M.; Ackermann, A.; Leuenberger, D.; Niederhauser, B.

    2017-12-01

    To answer the needs of air quality and climate monitoring networks, two new gas generators were developed and manufactured at METAS in order to dynamically generate SI-traceable reference gas mixtures for reactive compounds at atmospheric concentrations. The technical features of the transportable generators allow for the realization of such gas standards for reactive compounds (e.g. NO2, volatile organic compounds) in the nmol · mol-1 range (ReGaS2), and fluorinated gases in the pmol ṡ mol-1 range (ReGaS3). The generation method is based on permeation and dynamic dilution. The transportable generators have multiple individual permeation chambers allowing for the generation of mixtures containing up to five different compounds. This mixture is then diluted using mass flow controllers, thus making the production process adaptable to generate the required amount of substance fraction. All parts of ReGaS2 in contact with the gas mixture are coated to reduce adsorption/desorption processes. Each input parameter required to calculate the generated amount of substance fraction is calibrated with SI-primary standards. The stability and reproducibility of the generated amount of substance fractions were tested with NO2 for ReGaS2 and HFC-125 for ReGaS3. They demonstrate stability over 1-4 d better than 0.4% and 0.8%, respectively, and reproducibility better than 0.7% and 1%, respectively. Finally, the relative expanded uncertainty of the generated amount of substance fraction is smaller than 3% with the major contributions coming from the uncertainty of the permeation rate and/or of the purity of the matrix gas. These relative expanded uncertainties meet then the needs of the data quality objectives fixed by the World Meteorological Organization.

  8. Rational reference levels for Pacific Coast radioactive pollution studies supplied by samples from northern Baja California

    International Nuclear Information System (INIS)

    Folsom, T.R.

    1974-01-01

    Background levels of radioactivity in the marine environment along the Pacific Coast are at present extremely low. However, these certainly will rise along with the growth of coastal populations and with the increased use of nuclear energy. It would be desirable to anticipate where and how fast concentrations of artificial radioactivities may reach unacceptable levels in coastal water. Successful prediction of this sort requires knowing how the ocean responds, in given regions, to specific inputs. Fortunately, some of the fate of a large class of radioactive pollutants that must be faced in the future may be inferred from careful studies during the past 20 years of the behavior of certain constituents of nuclear fallout that have entered the ocean along the coasts of California and Baja California. (CH)

  9. Study and Analysis of a Natural Reference Frame Current Controller for a Multi-Level H-Bridge Power Converter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Iov, Florin; Zanchetta, P.

    2008-01-01

    will be needed in order to control the power flow and to ensure proper and secure operation of this future grid with an increased level of renewable power. These power converters must be able to provide intelligent power management as well as ancillary services. This paper presents an analysis of the natural...... reference frame controller, based on proportional-resonant (PR) technique, for a multi-level H-bridge power converter for Universal and Flexible Power Management in Future Electricity Network. The proposed method is tested in terms of harmonic content in the Point of Common Coupling (PCC), voltage...

  10. Reservoir characterisation by a binary level set method and adaptive multiscale estimation

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Lars Kristian

    2006-01-15

    The main focus of this work is on estimation of the absolute permeability as a solution of an inverse problem. We have both considered a single-phase and a two-phase flow model. Two novel approaches have been introduced and tested numerical for solving the inverse problems. The first approach is a multi scale zonation technique which is treated in Paper A. The purpose of the work in this paper is to find a coarse scale solution based on production data from wells. In the suggested approach, the robustness of an already developed method, the adaptive multi scale estimation (AME), has been improved by utilising information from several candidate solutions generated by a stochastic optimizer. The new approach also suggests a way of combining a stochastic and a gradient search method, which in general is a problematic issue. The second approach is a piecewise constant level set approach and is applied in Paper B, C, D and E. Paper B considers the stationary single-phase problem, while Paper C, D and E use a two-phase flow model. In the two-phase flow problem we have utilised information from both production data in wells and spatially distributed data gathered from seismic surveys. Due to the higher content of information provided by the spatially distributed data, we search solutions on a slightly finer scale than one typically does with only production data included. The applied level set method is suitable for reconstruction of fields with a supposed known facies-type of solution. That is, the solution should be close to piecewise constant. This information is utilised through a strong restriction of the number of constant levels in the estimate. On the other hand, the flexibility in the geometries of the zones is much larger for this method than in a typical zonation approach, for example the multi scale approach applied in Paper A. In all these papers, the numerical studies are done on synthetic data sets. An advantage of synthetic data studies is that the true

  11. CT Findings of Disease with Elevated Serum D-Dimer Levels in an Emergency Room Setting

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ji Youn; Kwon, Woo Cheol; Kim, Young Ju [Dept. of Radiology, Wonju Christian Hospital, Yensei University Wonju College of Medicine, Wonju (Korea, Republic of)

    2012-01-15

    Pulmonary embolism and deep vein thrombosis are the leading causes of elevated serum D-dimer levels in the emergency room. Although D-dimer is a useful screening test because of its high sensitivity and negative predictive value, it has a low specificity. In addition, D-dimer can be elevated in various diseases. Therefore, information on the various diseases with elevated D-dimer levels and their radiologic findings may allow for accurate diagnosis and proper management. Herein, we report the CT findings of various diseases with elevated D-dimer levels in an emergency room setting, including an intravascular contrast filling defect with associated findings in a venous thromboembolism, fracture with soft tissue swelling and hematoma formation in a trauma patient, enlargement with contrast enhancement in the infected organ of a patient, coronary artery stenosis with a perfusion defect of the myocardium in a patient with acute myocardial infarction, high density of acute thrombus in a cerebral vessel with a low density of affected brain parenchyma in an acute cerebral infarction, intimal flap with two separated lumens in a case of aortic dissection, organ involvement of malignancy in a cancer patient, and atrophy of a liver with a dilated portal vein and associated findings.

  12. Glycated albumin is set lower in relation to plasma glucose levels in patients with Cushing's syndrome.

    Science.gov (United States)

    Kitamura, Tetsuhiro; Otsuki, Michio; Tamada, Daisuke; Tabuchi, Yukiko; Mukai, Kosuke; Morita, Shinya; Kasayama, Soji; Shimomura, Iichiro; Koga, Masafumi

    2013-09-23

    Glycated albumin (GA) is an indicator of glycemic control, which has some specific characters in comparison with HbA1c. Since glucocorticoids (GC) promote protein catabolism including serum albumin, GC excess state would influence GA levels. We therefore investigated GA levels in patients with Cushing's syndrome. We studied 16 patients with Cushing's syndrome (8 patients had diabetes mellitus and the remaining 8 patients were non-diabetic). Thirty-two patients with type 2 diabetes mellitus and 32 non-diabetic subjects matched for age, sex and BMI were used as controls. In the patients with Cushing's syndrome, GA was significantly correlated with HbA1c, but the regression line shifted downwards as compared with the controls. The GA/HbA1c ratio in the patients with Cushing's syndrome was also significantly lower than the controls. HbA1c in the non-diabetic patients with Cushing's syndrome was not different from the non-diabetic controls, whereas GA was significantly lower. In 7 patients with Cushing's syndrome who performed self-monitoring of blood glucose, the measured HbA1c was matched with HbA1c estimated from mean blood glucose, whereas the measured GA was significantly lower than the estimated GA. We clarified that GA is set lower in relation to plasma glucose levels in patients with Cushing's syndrome. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. CT Findings of Disease with Elevated Serum D-Dimer Levels in an Emergency Room Setting

    International Nuclear Information System (INIS)

    Choi, Ji Youn; Kwon, Woo Cheol; Kim, Young Ju

    2012-01-01

    Pulmonary embolism and deep vein thrombosis are the leading causes of elevated serum D-dimer levels in the emergency room. Although D-dimer is a useful screening test because of its high sensitivity and negative predictive value, it has a low specificity. In addition, D-dimer can be elevated in various diseases. Therefore, information on the various diseases with elevated D-dimer levels and their radiologic findings may allow for accurate diagnosis and proper management. Herein, we report the CT findings of various diseases with elevated D-dimer levels in an emergency room setting, including an intravascular contrast filling defect with associated findings in a venous thromboembolism, fracture with soft tissue swelling and hematoma formation in a trauma patient, enlargement with contrast enhancement in the infected organ of a patient, coronary artery stenosis with a perfusion defect of the myocardium in a patient with acute myocardial infarction, high density of acute thrombus in a cerebral vessel with a low density of affected brain parenchyma in an acute cerebral infarction, intimal flap with two separated lumens in a case of aortic dissection, organ involvement of malignancy in a cancer patient, and atrophy of a liver with a dilated portal vein and associated findings.

  14. Evaluation of the uncertainty around the mean level of 137Cs fallout at undisturbed reference site: A simple statistical approach

    International Nuclear Information System (INIS)

    Mabit, L.; Gonsalves, B.C.; Chen, X.; Toloza, A.; Weltin, G.; Darby, I.G.; Padilla-Alvarez, R.

    2015-01-01

    One of the major issues related to the use of 137 Cs as a soil erosion/sedimentation tracer is the selection of the reference site which is used to estimate the initial 137 Cs fallout input (also termed reference inventory). The initial 137 Cs fallout input is a key component of the conversion models used to estimate erosion and sedimentation rates from the 137 Cs data set. The selection and evaluation of the validity of reference sites have been explained in detail in the recent IAEA TECDOC 1741 ‘‘Guidelines for using Fallout radionuclides to assess erosion and effectiveness of soil conservation strategies’’. An investigation was carried out at the experimental research station of the Austrian Agency for Health and Food Safety (AGES), in Austria, Grabenegg (48°07'40 N , 15°13'16 E ). Located at an altitude of 260 m a.s.l, with an annual average temperature of 8.4 °C and annual precipitation of 686 mm, the soil of this area has been classified as Gleyic Cambisol with a silt-loamy texture

  15. Transport equations, Level Set and Eulerian mechanics. Application to fluid-structure coupling

    International Nuclear Information System (INIS)

    Maitre, E.

    2008-11-01

    My works were devoted to numerical analysis of non-linear elliptic-parabolic equations, to neutron transport equation and to the simulation of fabrics draping. More recently I developed an Eulerian method based on a level set formulation of the immersed boundary method to deal with fluid-structure coupling problems arising in bio-mechanics. Some of the more efficient algorithms to solve the neutron transport equation make use of the splitting of the transport operator taking into account its characteristics. In the present work we introduced a new algorithm based on this splitting and an adaptation of minimal residual methods to infinite dimensional case. We present the case where the velocity space is of dimension 1 (slab geometry) and 2 (plane geometry) because the splitting is simpler in the former

  16. Numerical simulation of overflow at vertical weirs using a hybrid level set/VOF method

    Science.gov (United States)

    Lv, Xin; Zou, Qingping; Reeve, Dominic

    2011-10-01

    This paper presents the applications of a newly developed free surface flow model to the practical, while challenging overflow problems for weirs. Since the model takes advantage of the strengths of both the level set and volume of fluid methods and solves the Navier-Stokes equations on an unstructured mesh, it is capable of resolving the time evolution of very complex vortical motions, air entrainment and pressure variations due to violent deformations following overflow of the weir crest. In the present study, two different types of vertical weir, namely broad-crested and sharp-crested, are considered for validation purposes. The calculated overflow parameters such as pressure head distributions, velocity distributions, and water surface profiles are compared against experimental data as well as numerical results available in literature. A very good quantitative agreement has been obtained. The numerical model, thus, offers a good alternative to traditional experimental methods in the study of weir problems.

  17. Level set method for optimal shape design of MRAM core. Micromagnetic approach

    International Nuclear Information System (INIS)

    Melicher, Valdemar; Cimrak, Ivan; Keer, Roger van

    2008-01-01

    We aim at optimizing the shape of the magnetic core in MRAM memories. The evolution of the magnetization during the writing process is described by the Landau-Lifshitz equation (LLE). The actual shape of the core in one cell is characterized by the coefficient γ. Cost functional f=f(γ) expresses the quality of the writing process having in mind the competition between the full-select and the half-select element. We derive an explicit form of the derivative F=∂f/∂γ which allows for the use of gradient-type methods for the actual computation of the optimized shape (e.g., steepest descend method). The level set method (LSM) is employed for the representation of the piecewise constant coefficient γ

  18. Level-set segmentation of pulmonary nodules in megavolt electronic portal images using a CT prior

    International Nuclear Information System (INIS)

    Schildkraut, J. S.; Prosser, N.; Savakis, A.; Gomez, J.; Nazareth, D.; Singh, A. K.; Malhotra, H. K.

    2010-01-01

    Purpose: Pulmonary nodules present unique problems during radiation treatment due to nodule position uncertainty that is caused by respiration. The radiation field has to be enlarged to account for nodule motion during treatment. The purpose of this work is to provide a method of locating a pulmonary nodule in a megavolt portal image that can be used to reduce the internal target volume (ITV) during radiation therapy. A reduction in the ITV would result in a decrease in radiation toxicity to healthy tissue. Methods: Eight patients with nonsmall cell lung cancer were used in this study. CT scans that include the pulmonary nodule were captured with a GE Healthcare LightSpeed RT 16 scanner. Megavolt portal images were acquired with a Varian Trilogy unit equipped with an AS1000 electronic portal imaging device. The nodule localization method uses grayscale morphological filtering and level-set segmentation with a prior. The treatment-time portion of the algorithm is implemented on a graphical processing unit. Results: The method was retrospectively tested on eight cases that include a total of 151 megavolt portal image frames. The method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases. The treatment phase portion of the method has a subsecond execution time that makes it suitable for near-real-time nodule localization. Conclusions: A method was developed to localize a pulmonary nodule in a megavolt portal image. The method uses the characteristics of the nodule in a prior CT scan to enhance the nodule in the portal image and to identify the nodule region by level-set segmentation. In a retrospective study, the method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases studied.

  19. Level-set dynamics and mixing efficiency of passive and active scalars in DNS and LES of turbulent mixing layers

    NARCIS (Netherlands)

    Geurts, Bernard J.; Vreman, Bert; Kuerten, Hans; Luo, Kai H.

    2001-01-01

    The mixing efficiency in a turbulent mixing layer is quantified by monitoring the surface-area of level-sets of scalar fields. The Laplace transform is applied to numerically calculate integrals over arbitrary level-sets. The analysis includes both direct and large-eddy simulation and is used to

  20. Impact of low-level radiation with special reference to tritium in environment

    International Nuclear Information System (INIS)

    Bhatia, A.L.

    2005-01-01

    Radiation is invisible, but exists in various types, in the form of particles and/or energy bundles. The effects of low-level radiation seem very abstract since these can not be perceived by our sensory organs. The increase in natural background radiation from various inadvertent sources like tritium has the prospect of altering the entire scenario of billions of years' slow and steady biogenetic evolution. Mankind, by developing atomic technologies, is unleashing forces which it does understand but not beyond experimental findings. There is no wise sorcerer who can undo the damage we are causing. Tritium is a radioactive form of hydrogen that is produced in the reactor core. The released tritium replaces hydrogen in water. Tritium in water when gets ingested, causes continuos internal low-level beta radiation exposure over a long period. Proposed presentation will focus on the possible long term damage caused by its low-level exposure is dependent on the length of duration living tissue spends in the radiation field, not on the relative radiation field strength. As internal radiation pulses never stop, impact is continuous by the ambient radiation atmosphere. There is no chance to heal at the molecular level, except small chances of DNA repair since the organically bound tritium has greater severe influence with the slow turnover. Though the situation needs not be alarming with tritium, the studies on radiation damage on various parameters have given evidence of two compartments of radiation damage; the reparable or potentially lethal and the irreparable or lethal. With emerging new reports on the stochastic effects, those for which the probability, rather than the severity of an effect from tritium occurring as a function of dose also can not be ruled out. Biotoxicity of tritium in the form of induction of cancer, hereditary effects, teratogenesis and life shortening really needs an exhaustive investigation and warrants careful evaluation. However, a positive

  1. Characterization of mammographic masses based on level set segmentation with new image features and patient information

    International Nuclear Information System (INIS)

    Shi Jiazheng; Sahiner, Berkman; Chan Heangping; Ge Jun; Hadjiiski, Lubomir; Helvie, Mark A.; Nees, Alexis; Wu Yita; Wei Jun; Zhou Chuan; Zhang Yiheng; Cui Jing

    2008-01-01

    Computer-aided diagnosis (CAD) for characterization of mammographic masses as malignant or benign has the potential to assist radiologists in reducing the biopsy rate without increasing false negatives. The purpose of this study was to develop an automated method for mammographic mass segmentation and explore new image based features in combination with patient information in order to improve the performance of mass characterization. The authors' previous CAD system, which used the active contour segmentation, and morphological, textural, and spiculation features, has achieved promising results in mass characterization. The new CAD system is based on the level set method and includes two new types of image features related to the presence of microcalcifications with the mass and abruptness of the mass margin, and patient age. A linear discriminant analysis (LDA) classifier with stepwise feature selection was used to merge the extracted features into a classification score. The classification accuracy was evaluated using the area under the receiver operating characteristic curve. The authors' primary data set consisted of 427 biopsy-proven masses (200 malignant and 227 benign) in 909 regions of interest (ROIs) (451 malignant and 458 benign) from multiple mammographic views. Leave-one-case-out resampling was used for training and testing. The new CAD system based on the level set segmentation and the new mammographic feature space achieved a view-based A z value of 0.83±0.01. The improvement compared to the previous CAD system was statistically significant (p=0.02). When patient age was included in the new CAD system, view-based and case-based A z values were 0.85±0.01 and 0.87±0.02, respectively. The study also demonstrated the consistency of the newly developed CAD system by evaluating the statistics of the weights of the LDA classifiers in leave-one-case-out classification. Finally, an independent test on the publicly available digital database for screening

  2. Evaluation of alanine as a reference dosimeter for therapy level dose comparisons in megavoltage electron beams

    International Nuclear Information System (INIS)

    McEwen, Malcolm; Sharpe, Peter; Voros, Sandor

    2015-01-01

    When comparing absorbed dose standards from different laboratories (e.g. National Measurement Institutes, NMIs, for Key or Supplementary comparisons) it is rarely possible to carry out a direct comparison of primary standard instruments, and therefore some form of transfer detector is required. Historically, air-filled, unsealed ionization chambers have been used because of the long history of using these instruments, very good stability over many years, and ease of transport. However, the use of ion chambers for therapy-level comparisons is not without its problems. Findings from recent investigations suggest that ion chambers are prone to non-random variations, they are not completely robust to standard courier practices, and failure at any step in a comparison can render all measurements potentially useless. An alternative approach is to identify a transfer system that is insensitive to some of these concerns - effectively a dosimeter that is inexpensive, simple to use, robust, but with sufficient precision and of a size relevant to the disseminated quantity in question. The alanine dosimetry system has been successfully used in a number of situations as an audit dosimeter and therefore the purpose of this investigation was to determine whether alanine could also be used as the transfer detector for dosimetric comparisons, which require a lower value for the measurement uncertainty. A measurement protocol was developed for comparing primary standards of absorbed dose to water in high-energy electron beams using alanine pellets irradiated in a water-equivalent plastic phantom. A trial comparison has been carried out between three NMIs and has indicated that alanine is a suitable alternative to ion chambers, with the system used achieving a precision of 0.1%. Although the focus of the evaluation was on the performance of the dosimeter, the comparison results are encouraging, showing agreement at the level of the combined uncertainties (∼0.6%). Based on this

  3. Analysis of data relative to the update of diagnosis reference levels in radiology and nuclear medicine. Situation 2004-2006

    International Nuclear Information System (INIS)

    2008-01-01

    This report presents the results of the analysis of patients dosimetry data the radiology and nuclear medicine institutions have to transmit yearly to I.R.S.N. in application of the 12. february decree disposal relative to the diagnosis reference levels in radiology and nuclear medicine. The analysed dosimetry data concern the evaluations realised between the date of decree publication, the 16. march 2004 and 31. december 2006. The so considered results have to allow to the Nuclear Safety Authority to define the evolution needs of the regulation. Particularly, the analysis of delivered doses in radiology and the activities given in nuclear medicine lead to propositions on the possible update of reference values of some examination types. (N.C.)

  4. Cooperative Fuzzy Games Approach to Setting Target Levels of ECs in Quality Function Deployment

    Directory of Open Access Journals (Sweden)

    Zhihui Yang

    2014-01-01

    Full Text Available Quality function deployment (QFD can provide a means of translating customer requirements (CRs into engineering characteristics (ECs for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.

  5. A hybrid interface tracking - level set technique for multiphase flow with soluble surfactant

    Science.gov (United States)

    Shin, Seungwon; Chergui, Jalel; Juric, Damir; Kahouadji, Lyes; Matar, Omar K.; Craster, Richard V.

    2018-04-01

    A formulation for soluble surfactant transport in multiphase flows recently presented by Muradoglu and Tryggvason (JCP 274 (2014) 737-757) [17] is adapted to the context of the Level Contour Reconstruction Method, LCRM, (Shin et al. IJNMF 60 (2009) 753-778, [8]) which is a hybrid method that combines the advantages of the Front-tracking and Level Set methods. Particularly close attention is paid to the formulation and numerical implementation of the surface gradients of surfactant concentration and surface tension. Various benchmark tests are performed to demonstrate the accuracy of different elements of the algorithm. To verify surfactant mass conservation, values for surfactant diffusion along the interface are compared with the exact solution for the problem of uniform expansion of a sphere. The numerical implementation of the discontinuous boundary condition for the source term in the bulk concentration is compared with the approximate solution. Surface tension forces are tested for Marangoni drop translation. Our numerical results for drop deformation in simple shear are compared with experiments and results from previous simulations. All benchmarking tests compare well with existing data thus providing confidence that the adapted LCRM formulation for surfactant advection and diffusion is accurate and effective in three-dimensional multiphase flows with a structured mesh. We also demonstrate that this approach applies easily to massively parallel simulations.

  6. Cooperative fuzzy games approach to setting target levels of ECs in quality function deployment.

    Science.gov (United States)

    Yang, Zhihui; Chen, Yizeng; Yin, Yunqiang

    2014-01-01

    Quality function deployment (QFD) can provide a means of translating customer requirements (CRs) into engineering characteristics (ECs) for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.

  7. Generalized cost-effectiveness analysis for national-level priority-setting in the health sector

    Directory of Open Access Journals (Sweden)

    Edejer Tessa

    2003-12-01

    Full Text Available Abstract Cost-effectiveness analysis (CEA is potentially an important aid to public health decision-making but, with some notable exceptions, its use and impact at the level of individual countries is limited. A number of potential reasons may account for this, among them technical shortcomings associated with the generation of current economic evidence, political expediency, social preferences and systemic barriers to implementation. As a form of sectoral CEA, Generalized CEA sets out to overcome a number of these barriers to the appropriate use of cost-effectiveness information at the regional and country level. Its application via WHO-CHOICE provides a new economic evidence base, as well as underlying methodological developments, concerning the cost-effectiveness of a range of health interventions for leading causes of, and risk factors for, disease. The estimated sub-regional costs and effects of different interventions provided by WHO-CHOICE can readily be tailored to the specific context of individual countries, for example by adjustment to the quantity and unit prices of intervention inputs (costs or the coverage, efficacy and adherence rates of interventions (effectiveness. The potential usefulness of this information for health policy and planning is in assessing if current intervention strategies represent an efficient use of scarce resources, and which of the potential additional interventions that are not yet implemented, or not implemented fully, should be given priority on the grounds of cost-effectiveness. Health policy-makers and programme managers can use results from WHO-CHOICE as a valuable input into the planning and prioritization of services at national level, as well as a starting point for additional analyses of the trade-off between the efficiency of interventions in producing health and their impact on other key outcomes such as reducing inequalities and improving the health of the poor.

  8. Robust nuclei segmentation in cyto-histopathological images using statistical level set approach with topology preserving constraint

    Science.gov (United States)

    Taheri, Shaghayegh; Fevens, Thomas; Bui, Tien D.

    2017-02-01

    Computerized assessments for diagnosis or malignancy grading of cyto-histopathological specimens have drawn increased attention in the field of digital pathology. Automatic segmentation of cell nuclei is a fundamental step in such automated systems. Despite considerable research, nuclei segmentation is still a challenging task due noise, nonuniform illumination, and most importantly, in 2D projection images, overlapping and touching nuclei. In most published approaches, nuclei refinement is a post-processing step after segmentation, which usually refers to the task of detaching the aggregated nuclei or merging the over-segmented nuclei. In this work, we present a novel segmentation technique which effectively addresses the problem of individually segmenting touching or overlapping cell nuclei during the segmentation process. The proposed framework is a region-based segmentation method, which consists of three major modules: i) the image is passed through a color deconvolution step to extract the desired stains; ii) then the generalized fast radial symmetry transform is applied to the image followed by non-maxima suppression to specify the initial seed points for nuclei, and their corresponding GFRS ellipses which are interpreted as the initial nuclei borders for segmentation; iii) finally, these nuclei border initial curves are evolved through the use of a statistical level-set approach along with topology preserving criteria for segmentation and separation of nuclei at the same time. The proposed method is evaluated using Hematoxylin and Eosin, and fluorescent stained images, performing qualitative and quantitative analysis, showing that the method outperforms thresholding and watershed segmentation approaches.

  9. Home advantage in high-level volleyball varies according to set number.

    Science.gov (United States)

    Marcelino, Rui; Mesquita, Isabel; Palao Andrés, José Manuel; Sampaio, Jaime

    2009-01-01

    The aim of the present study was to identify the probability of winning each Volleyball set according to game location (home, away). Archival data was obtained from 275 sets in the 2005 Men's Senior World League and 65,949 actions were analysed. Set result (win, loss), game location (home, away), set number (first, second, third, fourth and fifth) and performance indicators (serve, reception, set, attack, dig and block) were the variables considered in this study. In a first moment, performance indicators were used in a logistic model of set result, by binary logistic regression analysis. After finding the adjusted logistic model, the log-odds of winning the set were analysed according to game location and set number. The results showed that winning a set is significantly related to performance indicators (Chisquare(18)=660.97, padvantage at the beginning of the game (first set) and in the two last sets of the game (fourth and fifth sets), probably due to facilities familiarity and crowd effects. Different game actions explain these advantages and showed that to win the first set is more important to take risk, through a better performance in the attack and block, and to win the final set is important to manage the risk through a better performance on the reception. These results may suggest intra-game variation in home advantage and can be most useful to better prepare and direct the competition. Key pointsHome teams always have more probability of winning the game than away teams.Home teams have higher performance in reception, set and attack in the total of the sets.The advantage of home teams is more pronounced at the beginning of the game (first set) and in two last sets of the game (fourth and fifth sets) suggesting intra-game variation in home advantage.Analysis by sets showed that home teams have a better performance in the attack and block in the first set and in the reception in the third and fifth sets.

  10. On the modeling of bubble evolution and transport using coupled level-set/CFD method

    International Nuclear Information System (INIS)

    Bartlomiej Wierzbicki; Steven P Antal; Michael Z Podowski

    2005-01-01

    Full text of publication follows: The ability to predict the shape of the gas/liquid/solid interfaces is important for various multiphase flow and heat transfer applications. Specific issues of interest to nuclear reactor thermal-hydraulics, include the evolution of the shape of bubbles attached to solid surfaces during nucleation, bubble surface interactions in complex geometries, etc. Additional problems, making the overall task even more complicated, are associated with the effect of material properties that may be significantly altered by the addition of minute amounts of impurities, such as surfactants or nano-particles. The present paper is concerned with the development of an innovative approach to model time-dependent shape of gas/liquid interfaces in the presence of solid walls. The proposed approach combines a modified level-set method with an advanced CFD code, NPHASE. The coupled numerical solver can be used to simulate the evolution of gas/liquid interfaces in two-phase flows for a variety of geometries and flow conditions, from individual bubbles to free surfaces (stratified flows). The issues discussed in the full paper will include: a description of the novel aspects of the proposed level-set concept based method, an overview of the NPHASE code modeling framework and a description of the coupling method between these two elements of the overall model. A particular attention will be give to the consistency and completeness of model formulation for the interfacial phenomena near the liquid/gas/solid triple line, and to the impact of the proposed numerical approach on the accuracy and consistency of predictions. The accuracy will be measured in terms of both the calculated shape of the interfaces and the gas and liquid velocity fields around the interfaces and in the entire computational domain. The results of model testing and validation will also be shown in the full paper. The situations analyzed will include: bubbles of different sizes and varying

  11. Analysis of data related to the update of diagnosis reference levels in radiology and nuclear medicine. Assessment 2009-2010

    International Nuclear Information System (INIS)

    Roch, Patrice; Celier, David

    2012-10-01

    This report presents and comments the results of the analysis of 'patient' dosimetric data which radiology and nuclear medicine establishments had to transmit to the IRSN. The first part concerns conventional radiology and the analysis is made from a general point of view, and then by examination type (in the case of adults and of children). A synthesis of results since 2004 is proposed in terms of transmitted data, of data representativeness, of influence of detection technology on the delivered dose, of evolution of diagnosis reference level. With the same approach, the next parts address scanography examinations and nuclear medicine

  12. Analysis of data related to the updating of diagnosis reference levels in radiology and nuclear medicine. Assessment 2007-2008

    International Nuclear Information System (INIS)

    2010-01-01

    This report presents the results of the analysis of 'patient' dosimetric data which radiology and nuclear medicine establishments must supply every year to the IRSN (the French Radioprotection and Nuclear Safety Institute) according to a decree related to diagnosis reference levels in radiology and nuclear medicine. The analysed dosimetric data concern assessments performed during 2007 and 2008. For the different concerned practices (radiology, scanography, nuclear medicine), the report proposes a presentation and a discussion of global data, and then a presentation of data either for different types of examination on adults and on children, or for the different parts of the body

  13. Evaluation of two-phase flow solvers using Level Set and Volume of Fluid methods

    Science.gov (United States)

    Bilger, C.; Aboukhedr, M.; Vogiatzaki, K.; Cant, R. S.

    2017-09-01

    Two principal methods have been used to simulate the evolution of two-phase immiscible flows of liquid and gas separated by an interface. These are the Level-Set (LS) method and the Volume of Fluid (VoF) method. Both methods attempt to represent the very sharp interface between the phases and to deal with the large jumps in physical properties associated with it. Both methods have their own strengths and weaknesses. For example, the VoF method is known to be prone to excessive numerical diffusion, while the basic LS method has some difficulty in conserving mass. Major progress has been made in remedying these deficiencies, and both methods have now reached a high level of physical accuracy. Nevertheless, there remains an issue, in that each of these methods has been developed by different research groups, using different codes and most importantly the implementations have been fine tuned to tackle different applications. Thus, it remains unclear what are the remaining advantages and drawbacks of each method relative to the other, and what might be the optimal way to unify them. In this paper, we address this gap by performing a direct comparison of two current state-of-the-art variations of these methods (LS: RCLSFoam and VoF: interPore) and implemented in the same code (OpenFoam). We subject both methods to a pair of benchmark test cases while using the same numerical meshes to examine a) the accuracy of curvature representation, b) the effect of tuning parameters, c) the ability to minimise spurious velocities and d) the ability to tackle fluids with very different densities. For each method, one of the test cases is chosen to be fairly benign while the other test case is expected to present a greater challenge. The results indicate that both methods can be made to work well on both test cases, while displaying different sensitivity to the relevant parameters.

  14. Bladder and bowel dysfunctions in 1748 children referred to pelvic physiotherapy: clinical characteristics and locomotor problems in primary, secondary, and tertiary healthcare settings.

    Science.gov (United States)

    van Engelenburg-van Lonkhuyzen, Marieke L; Bols, Esther M J; Benninga, Marc A; Verwijs, Wim A; de Bie, Rob A

    2017-02-01

    The aims of this study are to evaluate in a pragmatic cross-sectional study, the clinical characteristics of childhood bladder and/or bowel dysfunctions (CBBD) and locomotor problems in the primary through tertiary health care setting. It was hypothesized that problems would increase, going from primary to tertiary healthcare. Data were retrieved from patient-records of children (1-16 years) presenting with CBBD and visiting pelvic physiotherapists. Prevalence's of dysfunctions were compared between healthcare settings and gender using ANOVA and chi-square test. Agreement between physicians' diagnoses and parent-reported symptoms was evaluated (Cohen's Kappa). One thousand seventy hundred forty-eight children (mean age 7.7 years [SD 2.9], 48.9% boys) were included. Daytime urinary incontinence (P = 0.039) and enuresis (P physiotherapy are comparable in primary, secondary, and tertiary healthcare settings. • Concomitant CBBD appeared to be more prevalent than earlier reported. • Discrepancies exist between referring physicians' diagnoses and parent-reported symptoms.

  15. [Cardiac Synchronization Function Estimation Based on ASM Level Set Segmentation Method].

    Science.gov (United States)

    Zhang, Yaonan; Gao, Yuan; Tang, Liang; He, Ying; Zhang, Huie

    At present, there is no accurate and quantitative methods for the determination of cardiac mechanical synchronism, and quantitative determination of the synchronization function of the four cardiac cavities with medical images has a great clinical value. This paper uses the whole heart ultrasound image sequence, and segments the left & right atriums and left & right ventricles of each frame. After the segmentation, the number of pixels in each cavity and in each frame is recorded, and the areas of the four cavities of the image sequence are therefore obtained. The area change curves of the four cavities are further extracted, and the synchronous information of the four cavities is obtained. Because of the low SNR of Ultrasound images, the boundary lines of cardiac cavities are vague, so the extraction of cardiac contours is still a challenging problem. Therefore, the ASM model information is added to the traditional level set method to force the curve evolution process. According to the experimental results, the improved method improves the accuracy of the segmentation. Furthermore, based on the ventricular segmentation, the right and left ventricular systolic functions are evaluated, mainly according to the area changes. The synchronization of the four cavities of the heart is estimated based on the area changes and the volume changes.

  16. An integrated extended Kalman filter–implicit level set algorithm for monitoring planar hydraulic fractures

    International Nuclear Information System (INIS)

    Peirce, A; Rochinha, F

    2012-01-01

    We describe a novel approach to the inversion of elasto-static tiltmeter measurements to monitor planar hydraulic fractures propagating within three-dimensional elastic media. The technique combines the extended Kalman filter (EKF), which predicts and updates state estimates using tiltmeter measurement time-series, with a novel implicit level set algorithm (ILSA), which solves the coupled elasto-hydrodynamic equations. The EKF and ILSA are integrated to produce an algorithm to locate the unknown fracture-free boundary. A scaling argument is used to derive a strategy to tune the algorithm parameters to enable measurement information to compensate for unmodeled dynamics. Synthetic tiltmeter data for three numerical experiments are generated by introducing significant changes to the fracture geometry by altering the confining geological stress field. Even though there is no confining stress field in the dynamic model used by the new EKF-ILSA scheme, it is able to use synthetic data to arrive at remarkably accurate predictions of the fracture widths and footprints. These experiments also explore the robustness of the algorithm to noise and to placement of tiltmeter arrays operating in the near-field and far-field regimes. In these experiments, the appropriate parameter choices and strategies to improve the robustness of the algorithm to significant measurement noise are explored. (paper)

  17. Automatic Fontanel Extraction from Newborns' CT Images Using Variational Level Set

    Science.gov (United States)

    Kazemi, Kamran; Ghadimi, Sona; Lyaghat, Alireza; Tarighati, Alla; Golshaeyan, Narjes; Abrishami-Moghaddam, Hamid; Grebe, Reinhard; Gondary-Jouet, Catherine; Wallois, Fabrice

    A realistic head model is needed for source localization methods used for the study of epilepsy in neonates applying Electroencephalographic (EEG) measurements from the scalp. The earliest models consider the head as a series of concentric spheres, each layer corresponding to a different tissue whose conductivity is assumed to be homogeneous. The results of the source reconstruction depend highly on the electric conductivities of the tissues forming the head.The most used model is constituted of three layers (scalp, skull, and intracranial). Most of the major bones of the neonates’ skull are ossified at birth but can slightly move relative to each other. This is due to the sutures, fibrous membranes that at this stage of development connect the already ossified flat bones of the neurocranium. These weak parts of the neurocranium are called fontanels. Thus it is important to enter the exact geometry of fontaneles and flat bone in a source reconstruction because they show pronounced in conductivity. Computer Tomography (CT) imaging provides an excellent tool for non-invasive investigation of the skull which expresses itself in high contrast to all other tissues while the fontanels only can be identified as absence of bone, gaps in the skull formed by flat bone. Therefore, the aim of this paper is to extract the fontanels from CT images applying a variational level set method. We applied the proposed method to CT-images of five different subjects. The automatically extracted fontanels show good agreement with the manually extracted ones.

  18. Two-phase electro-hydrodynamic flow modeling by a conservative level set model.

    Science.gov (United States)

    Lin, Yuan

    2013-03-01

    The principles of electro-hydrodynamic (EHD) flow have been known for more than a century and have been adopted for various industrial applications, for example, fluid mixing and demixing. Analytical solutions of such EHD flow only exist in a limited number of scenarios, for example, predicting a small deformation of a single droplet in a uniform electric field. Numerical modeling of such phenomena can provide significant insights about EHDs multiphase flows. During the last decade, many numerical results have been reported to provide novel and useful tools of studying the multiphase EHD flow. Based on a conservative level set method, the proposed model is able to simulate large deformations of a droplet by a steady electric field, which is beyond the region of theoretic prediction. The model is validated for both leaky dielectrics and perfect dielectrics, and is found to be in excellent agreement with existing analytical solutions and numerical studies in the literature. Furthermore, simulations of the deformation of a water droplet in decyl alcohol in a steady electric field match better with published experimental data than the theoretical prediction for large deformations. Therefore the proposed model can serve as a practical and accurate tool for simulating two-phase EHD flow. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Modeling of Two-Phase Flow in Rough-Walled Fracture Using Level Set Method

    Directory of Open Access Journals (Sweden)

    Yunfeng Dai

    2017-01-01

    Full Text Available To describe accurately the flow characteristic of fracture scale displacements of immiscible fluids, an incompressible two-phase (crude oil and water flow model incorporating interfacial forces and nonzero contact angles is developed. The roughness of the two-dimensional synthetic rough-walled fractures is controlled with different fractal dimension parameters. Described by the Navier–Stokes equations, the moving interface between crude oil and water is tracked using level set method. The method accounts for differences in densities and viscosities of crude oil and water and includes the effect of interfacial force. The wettability of the rough fracture wall is taken into account by defining the contact angle and slip length. The curve of the invasion pressure-water volume fraction is generated by modeling two-phase flow during a sudden drainage. The volume fraction of water restricted in the rough-walled fracture is calculated by integrating the water volume and dividing by the total cavity volume of the fracture while the two-phase flow is quasistatic. The effect of invasion pressure of crude oil, roughness of fracture wall, and wettability of the wall on two-phase flow in rough-walled fracture is evaluated.

  20. Tokunaga and Horton self-similarity for level set trees of Markov chains

    International Nuclear Information System (INIS)

    Zaliapin, Ilia; Kovchegov, Yevgeniy

    2012-01-01

    Highlights: ► Self-similar properties of the level set trees for Markov chains are studied. ► Tokunaga and Horton self-similarity are established for symmetric Markov chains and regular Brownian motion. ► Strong, distributional self-similarity is established for symmetric Markov chains with exponential jumps. ► It is conjectured that fractional Brownian motions are Tokunaga self-similar. - Abstract: The Horton and Tokunaga branching laws provide a convenient framework for studying self-similarity in random trees. The Horton self-similarity is a weaker property that addresses the principal branching in a tree; it is a counterpart of the power-law size distribution for elements of a branching system. The stronger Tokunaga self-similarity addresses so-called side branching. The Horton and Tokunaga self-similarity have been empirically established in numerous observed and modeled systems, and proven for two paradigmatic models: the critical Galton–Watson branching process with finite progeny and the finite-tree representation of a regular Brownian excursion. This study establishes the Tokunaga and Horton self-similarity for a tree representation of a finite symmetric homogeneous Markov chain. We also extend the concept of Horton and Tokunaga self-similarity to infinite trees and establish self-similarity for an infinite-tree representation of a regular Brownian motion. We conjecture that fractional Brownian motions are also Tokunaga and Horton self-similar, with self-similarity parameters depending on the Hurst exponent.

  1. Delineating Facies Spatial Distribution by Integrating Ensemble Data Assimilation and Indicator Geostatistics with Level Set Transformation.

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, Glenn Edward; Song, Xuehang; Ye, Ming; Dai, Zhenxue; Zachara, John; Chen, Xingyuan

    2017-03-01

    A new approach is developed to delineate the spatial distribution of discrete facies (geological units that have unique distributions of hydraulic, physical, and/or chemical properties) conditioned not only on direct data (measurements directly related to facies properties, e.g., grain size distribution obtained from borehole samples) but also on indirect data (observations indirectly related to facies distribution, e.g., hydraulic head and tracer concentration). Our method integrates for the first time ensemble data assimilation with traditional transition probability-based geostatistics. The concept of level set is introduced to build shape parameterization that allows transformation between discrete facies indicators and continuous random variables. The spatial structure of different facies is simulated by indicator models using conditioning points selected adaptively during the iterative process of data assimilation. To evaluate the new method, a two-dimensional semi-synthetic example is designed to estimate the spatial distribution and permeability of two distinct facies from transient head data induced by pumping tests. The example demonstrates that our new method adequately captures the spatial pattern of facies distribution by imposing spatial continuity through conditioning points. The new method also reproduces the overall response in hydraulic head field with better accuracy compared to data assimilation with no constraints on spatial continuity on facies.

  2. Measurement of thermally ablated lesions in sonoelastographic images using level set methods

    Science.gov (United States)

    Castaneda, Benjamin; Tamez-Pena, Jose Gerardo; Zhang, Man; Hoyt, Kenneth; Bylund, Kevin; Christensen, Jared; Saad, Wael; Strang, John; Rubens, Deborah J.; Parker, Kevin J.

    2008-03-01

    The capability of sonoelastography to detect lesions based on elasticity contrast can be applied to monitor the creation of thermally ablated lesion. Currently, segmentation of lesions depicted in sonoelastographic images is performed manually which can be a time consuming process and prone to significant intra- and inter-observer variability. This work presents a semi-automated segmentation algorithm for sonoelastographic data. The user starts by planting a seed in the perceived center of the lesion. Fast marching methods use this information to create an initial estimate of the lesion. Subsequently, level set methods refine its final shape by attaching the segmented contour to edges in the image while maintaining smoothness. The algorithm is applied to in vivo sonoelastographic images from twenty five thermal ablated lesions created in porcine livers. The estimated area is compared to results from manual segmentation and gross pathology images. Results show that the algorithm outperforms manual segmentation in accuracy, inter- and intra-observer variability. The processing time per image is significantly reduced.

  3. Serum Inhibin B and follicle-stimulating hormone levels as tools in the evaluation of infertile men: significance of adequate reference values from proven fertile men

    DEFF Research Database (Denmark)

    Andersson, A.-M.; Petersen, Jørgen Holm; Jørgensen, N.

    2004-01-01

    Inhibin B and FSH levels in 289 idiopathic infertile men were compared with reference materials consisting of 303 proven fertile men (reference group 1) and 307 healthy men from the general population with unknown fertility status (reference group 2). The diagnostic power of these two serum markers...... of spermatogenesis was evaluated by the use of receiver operating characteristic plot analysis, and an example of how both markers can be used simultaneously in a bivariate reference chart is presented. Inhibin B levels were significantly lower and FSH levels were significantly higher in the infertile men, compared...

  4. Selection and validation of a set of reliable reference genes for quantitative RT-PCR studies in the brain of the Cephalopod Mollusc Octopus vulgaris

    Directory of Open Access Journals (Sweden)

    Biffali Elio

    2009-07-01

    Full Text Available Abstract Background Quantitative real-time polymerase chain reaction (RT-qPCR is valuable for studying the molecular events underlying physiological and behavioral phenomena. Normalization of real-time PCR data is critical for a reliable mRNA quantification. Here we identify reference genes to be utilized in RT-qPCR experiments to normalize and monitor the expression of target genes in the brain of the cephalopod mollusc Octopus vulgaris, an invertebrate. Such an approach is novel for this taxon and of advantage in future experiments given the complexity of the behavioral repertoire of this species when compared with its relatively simple neural organization. Results We chose 16S, and 18S rRNA, actB, EEF1A, tubA and ubi as candidate reference genes (housekeeping genes, HKG. The expression of 16S and 18S was highly variable and did not meet the requirements of candidate HKG. The expression of the other genes was almost stable and uniform among samples. We analyzed the expression of HKG into two different set of animals using tissues taken from the central nervous system (brain parts and mantle (here considered as control tissue by BestKeeper, geNorm and NormFinder. We found that HKG expressions differed considerably with respect to brain area and octopus samples in an HKG-specific manner. However, when the mantle is treated as control tissue and the entire central nervous system is considered, NormFinder revealed tubA and ubi as the most suitable HKG pair. These two genes were utilized to evaluate the relative expression of the genes FoxP, creb, dat and TH in O. vulgaris. Conclusion We analyzed the expression profiles of some genes here identified for O. vulgaris by applying RT-qPCR analysis for the first time in cephalopods. We validated candidate reference genes and found the expression of ubi and tubA to be the most appropriate to evaluate the expression of target genes in the brain of different octopuses. Our results also underline the

  5. Reference datum level

    Digital Repository Service at National Institute of Oceanography (India)

    Pathak, M.C.; Kotnala, K.L.

    stream_size 5 stream_content_type text/plain stream_name Trg_Calculat_Water_Depth_Chart_Datum_1991_25.pdf.txt stream_source_info Trg_Calculat_Water_Depth_Chart_Datum_1991_25.pdf.txt Content-Encoding ISO-8859-1 Content-Type text.../plain; charset=ISO-8859-1 ...

  6. Investigation of reference levels and radiation dose associated with abdominal EVAR (endovascular aneurysm repair) procedures across several European Centres

    Energy Technology Data Exchange (ETDEWEB)

    Tuthill, E.; Rainford, L. [University College Dublin, Diagnostic Imaging, School of Medicine, Dublin (Ireland); O' Hora, L.; O' Donohoe, M. [Mater Misericordiae University Hospital, Dublin (Ireland); Panci, S. [San Giovanni di Dio Hospital, Florence (Italy); Gilligan, P.; Fox, E. [Mater Private Hospital, Dublin (Ireland); Campion, D. [Mauriziano-Umberto Hospital, Turin (Italy); Trenti, R. [Policlinico S. Orsola-Malpighi, Bologna (Italy); Catania, D. [AITRI, Association of Italian Interventional Radiographers, Milan (Italy)

    2017-11-15

    Endovascular aneurysm repair (EVAR) is considered the treatment of choice for abdominal aortic aneurysms with suitable anatomy. In order to improve radiation safety, European Directive (2013/59) requires member states to implement diagnostic reference levels (DRLs) in radio-diagnostic and interventional procedures. This study aimed to determine local DRLs for EVAR across five European centres and identify an interim European DRL, which currently remains unestablished. Retrospective data was collected for 180 standard EVARs performed between January 2014 and July 2015 from five specialist centres in Ireland (n=2) and Italy (n=3). Data capture included: air kerma-area product (P{sub KA}), total air kerma at the reference point (K{sub a,r}), fluoroscopic time (FT), number of acquisitions, frame rate of acquisition, type of acquisition, patient height, weight, and gender. The mean values for each site A, B, C, D, and E were: P{sub KA}s of 4343 ± 994 μGym{sup 2}, 18,200 ± 2141 μGym{sup 2}, 11,423 ± 1390 μGym{sup 2}, 7796 ± 704 μGym{sup 2}, 31,897 ± 5798 μGym{sup 2}; FTs of 816 ± 92 s, 950 ± 150 s, 708 ± 70 s, 972 ± 61 s, 827 ± 118 s; and number of acquisitions of 6.72 ± 0.56, 10.38 ± 1.54, 4.74 ± 0.19, 5.64 ± 0.36, 7.28 ± 0.65, respectively. The overall pooled 75th percentile P{sub KA} was 15,849 μGym{sup 2}. Local reference levels were identified. The pooled data has been used to establish an interim European DRL for EVAR procedures. (orig.)

  7. Flipping for success: evaluating the effectiveness of a novel teaching approach in a graduate level setting.

    Science.gov (United States)

    Moraros, John; Islam, Adiba; Yu, Stan; Banow, Ryan; Schindelka, Barbara

    2015-02-28

    opportunities based on problem-solving activities and offer timely feedback/guidance to students. Yet in our study, this teaching style had its fair share of challenges, which were largely dependent on the use and management of technology. Despite these challenges, the Flipped Classroom proved to be a novel and effective teaching approach at the graduate level setting.

  8. DESIRE FOR LEVELS. Background study for the policy document "Setting Environmental Quality Standards for Water and Soil"

    NARCIS (Netherlands)

    van de Meent D; Aldenberg T; Canton JH; van Gestel CAM; Slooff W

    1990-01-01

    The report provides scientific support for setting environmental quality objectives for water, sediment and soil. Quality criteria are not set in this report. Only options for decisions are given. The report is restricted to the derivation of the 'maximally acceptable risk' levels (MAR)

  9. Toward accurate tooth segmentation from computed tomography images using a hybrid level set model

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Yangzhou; Zhao, Qunfei [Department of Automation, Shanghai Jiao Tong University, and Key Laboratory of System Control and Information Processing, Ministry of Education of China, Shanghai 200240 (China); Xia, Zeyang, E-mail: zy.xia@siat.ac.cn, E-mail: jing.xiong@siat.ac.cn; Hu, Ying [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, and The Chinese University of Hong Kong, Shenzhen 518055 (China); Xiong, Jing, E-mail: zy.xia@siat.ac.cn, E-mail: jing.xiong@siat.ac.cn [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 510855 (China); Zhang, Jianwei [TAMS, Department of Informatics, University of Hamburg, Hamburg 22527 (Germany)

    2015-01-15

    Purpose: A three-dimensional (3D) model of the teeth provides important information for orthodontic diagnosis and treatment planning. Tooth segmentation is an essential step in generating the 3D digital model from computed tomography (CT) images. The aim of this study is to develop an accurate and efficient tooth segmentation method from CT images. Methods: The 3D dental CT volumetric images are segmented slice by slice in a two-dimensional (2D) transverse plane. The 2D segmentation is composed of a manual initialization step and an automatic slice by slice segmentation step. In the manual initialization step, the user manually picks a starting slice and selects a seed point for each tooth in this slice. In the automatic slice segmentation step, a developed hybrid level set model is applied to segment tooth contours from each slice. Tooth contour propagation strategy is employed to initialize the level set function automatically. Cone beam CT (CBCT) images of two subjects were used to tune the parameters. Images of 16 additional subjects were used to validate the performance of the method. Volume overlap metrics and surface distance metrics were adopted to assess the segmentation accuracy quantitatively. The volume overlap metrics were volume difference (VD, mm{sup 3}) and Dice similarity coefficient (DSC, %). The surface distance metrics were average symmetric surface distance (ASSD, mm), RMS (root mean square) symmetric surface distance (RMSSSD, mm), and maximum symmetric surface distance (MSSD, mm). Computation time was recorded to assess the efficiency. The performance of the proposed method has been compared with two state-of-the-art methods. Results: For the tested CBCT images, the VD, DSC, ASSD, RMSSSD, and MSSD for the incisor were 38.16 ± 12.94 mm{sup 3}, 88.82 ± 2.14%, 0.29 ± 0.03 mm, 0.32 ± 0.08 mm, and 1.25 ± 0.58 mm, respectively; the VD, DSC, ASSD, RMSSSD, and MSSD for the canine were 49.12 ± 9.33 mm{sup 3}, 91.57 ± 0.82%, 0.27 ± 0.02 mm, 0

  10. Toward accurate tooth segmentation from computed tomography images using a hybrid level set model

    International Nuclear Information System (INIS)

    Gan, Yangzhou; Zhao, Qunfei; Xia, Zeyang; Hu, Ying; Xiong, Jing; Zhang, Jianwei

    2015-01-01

    Purpose: A three-dimensional (3D) model of the teeth provides important information for orthodontic diagnosis and treatment planning. Tooth segmentation is an essential step in generating the 3D digital model from computed tomography (CT) images. The aim of this study is to develop an accurate and efficient tooth segmentation method from CT images. Methods: The 3D dental CT volumetric images are segmented slice by slice in a two-dimensional (2D) transverse plane. The 2D segmentation is composed of a manual initialization step and an automatic slice by slice segmentation step. In the manual initialization step, the user manually picks a starting slice and selects a seed point for each tooth in this slice. In the automatic slice segmentation step, a developed hybrid level set model is applied to segment tooth contours from each slice. Tooth contour propagation strategy is employed to initialize the level set function automatically. Cone beam CT (CBCT) images of two subjects were used to tune the parameters. Images of 16 additional subjects were used to validate the performance of the method. Volume overlap metrics and surface distance metrics were adopted to assess the segmentation accuracy quantitatively. The volume overlap metrics were volume difference (VD, mm 3 ) and Dice similarity coefficient (DSC, %). The surface distance metrics were average symmetric surface distance (ASSD, mm), RMS (root mean square) symmetric surface distance (RMSSSD, mm), and maximum symmetric surface distance (MSSD, mm). Computation time was recorded to assess the efficiency. The performance of the proposed method has been compared with two state-of-the-art methods. Results: For the tested CBCT images, the VD, DSC, ASSD, RMSSSD, and MSSD for the incisor were 38.16 ± 12.94 mm 3 , 88.82 ± 2.14%, 0.29 ± 0.03 mm, 0.32 ± 0.08 mm, and 1.25 ± 0.58 mm, respectively; the VD, DSC, ASSD, RMSSSD, and MSSD for the canine were 49.12 ± 9.33 mm 3 , 91.57 ± 0.82%, 0.27 ± 0.02 mm, 0.28 ± 0.03 mm

  11. Multiatlas segmentation of thoracic and abdominal anatomy with level set-based local search.

    Science.gov (United States)

    Schreibmann, Eduard; Marcus, David M; Fox, Tim

    2014-07-08

    Segmentation of organs at risk (OARs) remains one of the most time-consuming tasks in radiotherapy treatment planning. Atlas-based segmentation methods using single templates have emerged as a practical approach to automate the process for brain or head and neck anatomy, but pose significant challenges in regions where large interpatient variations are present. We show that significant changes are needed to autosegment thoracic and abdominal datasets by combining multi-atlas deformable registration with a level set-based local search. Segmentation is hierarchical, with a first stage detecting bulk organ location, and a second step adapting the segmentation to fine details present in the patient scan. The first stage is based on warping multiple presegmented templates to the new patient anatomy using a multimodality deformable registration algorithm able to cope with changes in scanning conditions and artifacts. These segmentations are compacted in a probabilistic map of organ shape using the STAPLE algorithm. Final segmentation is obtained by adjusting the probability map for each organ type, using customized combinations of delineation filters exploiting prior knowledge of organ characteristics. Validation is performed by comparing automated and manual segmentation using the Dice coefficient, measured at an average of 0.971 for the aorta, 0.869 for the trachea, 0.958 for the lungs, 0.788 for the heart, 0.912 for the liver, 0.884 for the kidneys, 0.888 for the vertebrae, 0.863 for the spleen, and 0.740 for the spinal cord. Accurate atlas segmentation for abdominal and thoracic regions can be achieved with the usage of a multi-atlas and perstructure refinement strategy. To improve clinical workflow and efficiency, the algorithm was embedded in a software service, applying the algorithm automatically on acquired scans without any user interaction.

  12. Sensitivity Analysis of features in tolerancing based on constraint function level sets

    International Nuclear Information System (INIS)

    Ziegler, Philipp; Wartzack, Sandro

    2015-01-01

    Usually, the geometry of the manufactured product inherently varies from the nominal geometry. This may negatively affect the product functions and properties (such as quality and reliability), as well as the assemblability of the single components. In order to avoid this, the geometric variation of these component surfaces and associated geometry elements (like hole axes) are restricted by tolerances. Since tighter tolerances lead to significant higher manufacturing costs, tolerances should be specified carefully. Therefore, the impact of deviating component surfaces on functions, properties and assemblability of the product has to be analyzed. As physical experiments are expensive, methods of statistical tolerance analysis tools are widely used in engineering design. Current tolerance simulation tools lack of an appropriate indicator for the impact of deviating component surfaces. In the adoption of Sensitivity Analysis methods, there are several challenges, which arise from the specific framework in tolerancing. This paper presents an approach to adopt Sensitivity Analysis methods on current tolerance simulations with an interface module, which bases on level sets of constraint functions for parameters of the simulation model. The paper is an extension and generalization of Ziegler and Wartzack [1]. Mathematical properties of the constraint functions (convexity, homogeneity), which are important for the computational costs of the Sensitivity Analysis, are shown. The practical use of the method is illustrated in a case study of a plain bearing. - Highlights: • Alternative definition of Deviation Domains. • Proof of mathematical properties of the Deviation Domains. • Definition of the interface between Deviation Domains and Sensitivity Analysis. • Sensitivity analysis of a gearbox to show the methods practical use

  13. CT liver volumetry using geodesic active contour segmentation with a level-set algorithm

    Science.gov (United States)

    Suzuki, Kenji; Epstein, Mark L.; Kohlbrenner, Ryan; Obajuluwa, Ademola; Xu, Jianwu; Hori, Masatoshi; Baron, Richard

    2010-03-01

    Automatic liver segmentation on CT images is challenging because the liver often abuts other organs of a similar density. Our purpose was to develop an accurate automated liver segmentation scheme for measuring liver volumes. We developed an automated volumetry scheme for the liver in CT based on a 5 step schema. First, an anisotropic smoothing filter was applied to portal-venous phase CT images to remove noise while preserving the liver structure, followed by an edge enhancer to enhance the liver boundary. By using the boundary-enhanced image as a speed function, a fastmarching algorithm generated an initial surface that roughly estimated the liver shape. A geodesic-active-contour segmentation algorithm coupled with level-set contour-evolution refined the initial surface so as to more precisely fit the liver boundary. The liver volume was calculated based on the refined liver surface. Hepatic CT scans of eighteen prospective liver donors were obtained under a liver transplant protocol with a multi-detector CT system. Automated liver volumes obtained were compared with those manually traced by a radiologist, used as "gold standard." The mean liver volume obtained with our scheme was 1,520 cc, whereas the mean manual volume was 1,486 cc, with the mean absolute difference of 104 cc (7.0%). CT liver volumetrics based on an automated scheme agreed excellently with "goldstandard" manual volumetrics (intra-class correlation coefficient was 0.95) with no statistically significant difference (p(F<=f)=0.32), and required substantially less completion time. Our automated scheme provides an efficient and accurate way of measuring liver volumes.

  14. Shape Reconstruction of Thin Electromagnetic Inclusions via Boundary Measurements: Level-Set Method Combined with the Topological Derivative

    Directory of Open Access Journals (Sweden)

    Won-Kwang Park

    2013-01-01

    Full Text Available An inverse problem for reconstructing arbitrary-shaped thin penetrable electromagnetic inclusions concealed in a homogeneous material is considered in this paper. For this purpose, the level-set evolution method is adopted. The topological derivative concept is incorporated in order to evaluate the evolution speed of the level-set functions. The results of the corresponding numerical simulations with and without noise are presented in this paper.

  15. Joint inversion of geophysical data using petrophysical clustering and facies deformation wth the level set technique

    Science.gov (United States)

    Revil, A.

    2015-12-01

    Geological expertise and petrophysical relationships can be brought together to provide prior information while inverting multiple geophysical datasets. The merging of such information can result in more realistic solution in the distribution of the model parameters, reducing ipse facto the non-uniqueness of the inverse problem. We consider two level of heterogeneities: facies, described by facies boundaries and heteroegenities inside each facies determined by a correlogram. In this presentation, we pose the geophysical inverse problem in terms of Gaussian random fields with mean functions controlled by petrophysical relationships and covariance functions controlled by a prior geological cross-section, including the definition of spatial boundaries for the geological facies. The petrophysical relationship problem is formulated as a regression problem upon each facies. The inversion of the geophysical data is performed in a Bayesian framework. We demonstrate the usefulness of this strategy using a first synthetic case for which we perform a joint inversion of gravity and galvanometric resistivity data with the stations located at the ground surface. The joint inversion is used to recover the density and resistivity distributions of the subsurface. In a second step, we consider the possibility that the facies boundaries are deformable and their shapes are inverted as well. We use the level set approach to perform such deformation preserving prior topological properties of the facies throughout the inversion. With the help of prior facies petrophysical relationships and topological characteristic of each facies, we make posterior inference about multiple geophysical tomograms based on their corresponding geophysical data misfits. The method is applied to a second synthetic case showing that we can recover the heterogeneities inside the facies, the mean values for the petrophysical properties, and, to some extent, the facies boundaries using the 2D joint inversion of

  16. Correlation between Serum Aldosterone Level and Hearing Condition of Elderly Patients Referred to Otolaryngology Services of Hamadan, Western Iran

    Directory of Open Access Journals (Sweden)

    Dr. Farhad Farahani

    2010-06-01

    Full Text Available Background and Aim: Recently, more attention was paid to the direct protective effect of aldosterone against hearing impairment in elderly patients. The aim of this study was determination of possible correlation between serum aldosterone level and hearing condition of elderly patients that referred to the Otolaryngology services of Hamadan in 2005-2006.Methods: In this case control study 54 (27 males,27 females persons above 60 years old were evaluated. They contained twenty eight cases with normal hearing and 26 cases with presbycusis. Persons with any abnormal biochemical finding or history of conditions that predispose them to the sensorineural hearing loss (SNHL were excluded. In both groups serum level of sodium, potassium and aldosterone were measured and hearing condition evaluated by puretone, speech and immitance audiometry.Results: Statistical relationship between serum aldostrone level and hearing condition, sex, configuration of audiogram and speech discrimination score (SDS were not significant. In addition, no significant relationship between sodium and potassium levels with hearing condition was found (p>0.05.Conclusion: This study could not confirm protective effect of aldostrone against presbycusis. This discrepancy may originate from epidemiologic differences, laboratory errors or small sample size.

  17. Cuban typical doses for 99mTc-DMSA renal gammagraphy studies: a methodology for the establishment of reference levels

    International Nuclear Information System (INIS)

    Diaz Barreto, M.; Varela Corona, C.; Lopez Bejerano, G.M.; Perea Diaz, M.; Paz Viera, J.E.

    2008-01-01

    Since a handful of years ago, international rules on Radiological Protection include the principle of optimization of given dose to patients, if this procedure doesn't lessen diagnosis quality, and the establishment of reference levels of activity. For these reasons, the Radiological Protection staff of Cuban Institute of Nephrology's Nuclear Medicine Service, where morpho functional renal studies are carried out, 70% on infants and young children, started a research on that way. Thus, because their biggest incidence, 99m Tc -DMSA renal gammagraphy studies were chosen, using a General Electric 400 AT Planar Gamma Camera. Studied sample was randomly selected, including adults (12 peoples) and children (23); divided into 4 groups, lessen given dose step by step. Other items were kept in mind in the research, such age, weight, time delayed between administrations and image getting, getting time of each view and total time of the study, as well as radiopharmaceuticals quality and Gamma Camera performance. Image quality was evaluated for each case, using both, objective and subjective criteria. Objective evaluation was done by using contrast/noise ratios and variance of the random noise. They were used to develop clustering and discriminant analysis over the independent variables to detect groups with differentiated image quality from the physical and mathematical point of view. Subjective evaluation was performed using the criteria of two expert observers who had no information about the activity levels used. They evaluated image quality separately, giving a good, regular or bad evaluation for each image. As a conclusion, we found that it is possible to reduce the given activities in 50% and thus, indirectly, to reduce doses for workers and for the public. Additionally, we propose a methodology for the establishment of reference levels for 99m Tc -DMSA renal gammagraphy studies in Cuba, both, for adults and paediatric patients. (author)

  18. Establishment of national diagnostic reference level for renal doses in nuclear medicine departments at Khartoum-Sudan

    International Nuclear Information System (INIS)

    Alameen, Suhaib; Hamid, Alhadi; Rushdi, M. A. H.

    2016-01-01

    In this work we established a diagnostic reference level (DRL) for patient dose focusing on the investigation of activity to the kidneys during(99mTc-DTPA) kidney scan, selected two department nuclear medicine in main hospitals in Khartoum state. The DRLs is an investigational level used to identify unusually high radiation doses for common diagnostic medical in Nuclear Medicine procedures and suggested action levels above which a facility should review its methods and determine if acceptable image quality can be achieved at lower doses. The high specific activity of 99mTc makes it suitable as a first pass agent, for multiple or sequential studies, 99mTc diethylenetriaminepentaacetic acid (DTPA) is preferred to 99mTc-pertechnetate. Patients who had been prepared for the kidney scan 99mTc- DTPA were divided to three groups. The first group received dose less than 5 mCi, are represent (27.03%) from all patients, second group received dose 5 to 5.5 mCi are represent(66.67%) and the third group received dose from 5.6 to 6.2 mCi are represent (6.31%) from all patients 99mTc-DTPA. And according to the IAEA recommendation for adult doses(5-10mCi) this study show that about 93.1% of the sample examines by dose less than 5.5 mCi. The results presented will serve as a baseline data needed for deriving reference doses for renal examinations for nuclear medicine departments in Sudan.(Author)

  19. Improving district level health planning and priority setting in Tanzania through implementing accountability for reasonableness framework

    DEFF Research Database (Denmark)

    Maluka, Stephen; Kamuzora, Peter; Sebastián, Miguel San

    2010-01-01

    In 2006, researchers and decision-makers launched a five-year project - Response to Accountable Priority Setting for Trust in Health Systems (REACT) - to improve planning and priority-setting through implementing the Accountability for Reasonableness framework in Mbarali District, Tanzania...

  20. Predictive value of Borrelia burgdorferi IgG antibody levels in patients referred to a tertiary Lyme centre.

    Science.gov (United States)

    Zwerink, M; Zomer, T P; van Kooten, B; Blaauw, G; van Bemmel, T; van Hees, B C; Vermeeren, Y M; Landman, G W

    2018-03-01

    A two-step testing strategy is recommended in serological testing for Lyme borreliosis; positive and indeterminate enzyme-linked immunosorbent assay (ELISA) results are confirmed with immunoblots. Several ELISAs quantify the concentration of antibodies tested, however, no recommendation exists for an upper cut-off value at which an IgG ELISA is sufficient and the immunoblot can be omitted. The study objective was to determine at which IgG antibody level an immunoblot does not have any additional predictive value compared to ELISA results. Data of adult patients who visited a tertiary Lyme centre between 2008 and 2014 were analysed. Both an ELISA (Enzygnost Lyme link VlsE IgG) and immunoblot (recomLine blot Borrelia) were performed. Clinical data were extracted from the patient's digital medical record. Positive predictive values (PPVs) for either previous or active infection with Borrelia burgdorferi s.l. were calculated for different cut-off ELISA IgG antibody levels where the immunoblot was regarded as reference test. In total, 1454 patients were included. According to the two-step test strategy, 486 (33%), 69 (5%) and 899 (62%) patients had positive, indeterminate and negative Borrelia IgG serology, respectively. At IgG levels of 500 IU/ml and higher, all immunoblots were positive, resulting in a 100% PPV (95% CI: 97.0-100). At IgG levels of 200 IU/ml and higher, the PPV was 99.3% (95% CI: 97.4-99.8). In conclusion, at IgG levels of 200 IU/ml and higher, an ELISA was sufficient to detect antibodies to Borrelia burgdorferi s.l. At those IgG levels, a confirmatory immunoblot may be omitted in patients referred to a tertiary Lyme centre. Before these results can be implemented in routine diagnosis of Lyme borreliosis, confirmation of the results is necessary in other patient populations and using other quantitative ELISAs and immunoblots. Copyright © 2017 Elsevier GmbH. All rights reserved.

  1. A comparison of the suitability of patient dosimetry methods for establishing diagnostic dose reference levels and optimisation strategies

    International Nuclear Information System (INIS)

    Gfirtner, Hans; Moores, B. Michael; Stieve, Friedrich E.

    2008-01-01

    For 50 adult patients referred for chest radiography, air kerma at the diaphragm KD, dose area product and entrance skin dose were measured. The air kerma at the diaphragm and the dose area product were determined using Diamentor M4KDK(PTW) which allows measuring air kerma and dose area product simultaneously. For the measurement of entrance skin dose TLDs are used. A 50% variation in dose, incident dose as well as entrance skin dose, was registered for the same patient thickness. The recommendation of ICRP to perform the measurements for DRLs at 'representative patients' and that of the CEC to use 'standard-sized patients' seem to make little sense in the case of chest radiography. It could be demonstrated, that the dose area product is the least appropriate dose quantity for patient measurements and to define dose reference levels. For some radiological examinations like chest, pelvis and lumbar spine the dose area product is even sex dependent. Incident dose and entrance surface dose are of equal quality for patient dose measurements in diagnostic radiography. (author)

  2. Perturbational treatment of spin-orbit coupling for generally applicable high-level multi-reference methods

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Sebastian; Marquetand, Philipp; González, Leticia [Institute of Theoretical Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna (Austria); Müller, Thomas, E-mail: th.mueller@fz-juelich.de [Institute for Advanced Simulation, Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich (Germany); Plasser, Felix [Interdisciplinary Center for Scientific Computing, University of Heidelberg, Im Neuenheimer Feld 368, 69120 Heidelberg (Germany); Lischka, Hans [Institute of Theoretical Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna (Austria); Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061 (United States)

    2014-08-21

    An efficient perturbational treatment of spin-orbit coupling within the framework of high-level multi-reference techniques has been implemented in the most recent version of the COLUMBUS quantum chemistry package, extending the existing fully variational two-component (2c) multi-reference configuration interaction singles and doubles (MRCISD) method. The proposed scheme follows related implementations of quasi-degenerate perturbation theory (QDPT) model space techniques. Our model space is built either from uncontracted, large-scale scalar relativistic MRCISD wavefunctions or based on the scalar-relativistic solutions of the linear-response-theory-based multi-configurational averaged quadratic coupled cluster method (LRT-MRAQCC). The latter approach allows for a consistent, approximatively size-consistent and size-extensive treatment of spin-orbit coupling. The approach is described in detail and compared to a number of related techniques. The inherent accuracy of the QDPT approach is validated by comparing cuts of the potential energy surfaces of acrolein and its S, Se, and Te analoga with the corresponding data obtained from matching fully variational spin-orbit MRCISD calculations. The conceptual availability of approximate analytic gradients with respect to geometrical displacements is an attractive feature of the 2c-QDPT-MRCISD and 2c-QDPT-LRT-MRAQCC methods for structure optimization and ab inito molecular dynamics simulations.

  3. Perturbational treatment of spin-orbit coupling for generally applicable high-level multi-reference methods

    International Nuclear Information System (INIS)

    Mai, Sebastian; Marquetand, Philipp; González, Leticia; Müller, Thomas; Plasser, Felix; Lischka, Hans

    2014-01-01

    An efficient perturbational treatment of spin-orbit coupling within the framework of high-level multi-reference techniques has been implemented in the most recent version of the COLUMBUS quantum chemistry package, extending the existing fully variational two-component (2c) multi-reference configuration interaction singles and doubles (MRCISD) method. The proposed scheme follows related implementations of quasi-degenerate perturbation theory (QDPT) model space techniques. Our model space is built either from uncontracted, large-scale scalar relativistic MRCISD wavefunctions or based on the scalar-relativistic solutions of the linear-response-theory-based multi-configurational averaged quadratic coupled cluster method (LRT-MRAQCC). The latter approach allows for a consistent, approximatively size-consistent and size-extensive treatment of spin-orbit coupling. The approach is described in detail and compared to a number of related techniques. The inherent accuracy of the QDPT approach is validated by comparing cuts of the potential energy surfaces of acrolein and its S, Se, and Te analoga with the corresponding data obtained from matching fully variational spin-orbit MRCISD calculations. The conceptual availability of approximate analytic gradients with respect to geometrical displacements is an attractive feature of the 2c-QDPT-MRCISD and 2c-QDPT-LRT-MRAQCC methods for structure optimization and ab inito molecular dynamics simulations

  4. Local diagnostic reference levels, approaches and compare the values in the South Bohemia Region in view of radiation protection inspector

    International Nuclear Information System (INIS)

    Zemanova, E.

    2014-01-01

    This paper compares the value of local diagnostic reference levels(the LDRL)in health facilities of the South Bohemia Region. The work is motivated by questions of licensees, who would like to know their position in terms of the LDRL compared to other workplaces. Also by the activity of the inspector who can identify the problematic workplaces, where is necessary to increase attention to optimization, exposure, or justification. In connection with the ongoing internal audits in licensee workplaces the information about the status of the LDRL among others is current, motivating licensee to changes, optimization and verification of compliance with the recommendation of the National radiological standard of Ministry of Health (author)

  5. A new high-quality set of singly (H-2) and doubly (H-2 and O-18) stable isotope labeled reference waters for biomedical and other isotope-labeled research

    NARCIS (Netherlands)

    Faghihi, V.; Verstappen-Dumoulin, B. M. A. A.; Jansen, H. G.; van Dijk, G.; Aerts-Bijma, A. T.; Kerstel, E. R. T.; Groening, M.; Meijer, H. A. J.

    2015-01-01

    RATIONALE: Research using water with enriched levels of the rare stable isotopes of hydrogen and/or oxygen requires well-characterized enriched reference waters. The International Atomic Energy Agency (IAEA) did have such reference waters available, but these are now exhausted. New reference waters

  6. MO-AB-BRA-01: A Global Level Set Based Formulation for Volumetric Modulated Arc Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, D; Lyu, Q; Ruan, D; O’Connor, D; Low, D; Sheng, K [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, CA (United States)

    2016-06-15

    Purpose: The current clinical Volumetric Modulated Arc Therapy (VMAT) optimization is formulated as a non-convex problem and various greedy heuristics have been employed for an empirical solution, jeopardizing plan consistency and quality. We introduce a novel global direct aperture optimization method for VMAT to overcome these limitations. Methods: The global VMAT (gVMAT) planning was formulated as an optimization problem with an L2-norm fidelity term and an anisotropic total variation term. A level set function was used to describe the aperture shapes and adjacent aperture shapes were penalized to control MLC motion range. An alternating optimization strategy was implemented to solve the fluence intensity and aperture shapes simultaneously. Single arc gVMAT plans, utilizing 180 beams with 2° angular resolution, were generated for a glioblastoma multiforme (GBM), lung (LNG), and 2 head and neck cases—one with 3 PTVs (H&N3PTV) and one with 4 PTVs (H&N4PTV). The plans were compared against the clinical VMAT (cVMAT) plans utilizing two overlapping coplanar arcs. Results: The optimization of the gVMAT plans had converged within 600 iterations. gVMAT reduced the average max and mean OAR dose by 6.59% and 7.45% of the prescription dose. Reductions in max dose and mean dose were as high as 14.5 Gy in the LNG case and 15.3 Gy in the H&N3PTV case. PTV coverages (D95, D98, D99) were within 0.25% of the prescription dose. By globally considering all beams, the gVMAT optimizer allowed some beams to deliver higher intensities, yielding a dose distribution that resembles a static beam IMRT plan with beam orientation optimization. Conclusions: The novel VMAT approach allows for the search of an optimal plan in the global solution space and generates deliverable apertures directly. The single arc VMAT approach fully utilizes the digital linacs’ capability in dose rate and gantry rotation speed modulation. Varian Medical Systems, NIH grant R01CA188300, NIH grant R43CA183390.

  7. A finite element/level set model of polyurethane foam expansion and polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunini, Victor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noble, David R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tinsley, James [Honeywell Federal Manufacturing & Technologies, Kansas City, MO (United States); Mondy, Lisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Polyurethane foams are used widely for encapsulation and structural purposes because they are inexpensive, straightforward to process, amenable to a wide range of density variations (1 lb/ft3 - 50 lb/ft3), and able to fill complex molds quickly and effectively. Computational model of the filling and curing process are needed to reduce defects such as voids, out-of-specification density, density gradients, foam decomposition from high temperatures due to exotherms, and incomplete filling. This paper details the development of a computational fluid dynamics model of a moderate density PMDI structural foam, PMDI-10. PMDI is an isocyanate-based polyurethane foam, which is chemically blown with water. The polyol reacts with isocyanate to produces the polymer. PMDI- 10 is catalyzed giving it a short pot life: it foams and polymerizes to a solid within 5 minutes during normal processing. To achieve a higher density, the foam is over-packed to twice or more of its free rise density of 10 lb/ft3. The goal for modeling is to represent the expansion, filling of molds, and the polymerization of the foam. This will be used to reduce defects, optimize the mold design, troubleshoot the processed, and predict the final foam properties. A homogenized continuum model foaming and curing was developed based on reaction kinetics, documented in a recent paper; it uses a simplified mathematical formalism that decouples these two reactions. The chemo-rheology of PMDI is measured experimentally and fit to a generalized- Newtonian viscosity model that is dependent on the extent of cure, gas fraction, and temperature. The conservation equations, including the equations of motion, an energy balance, and three rate equations are solved via a stabilized finite element method. The equations are combined with a level set method to determine the location of the foam-gas interface as it evolves to fill the mold. Understanding the thermal history and loads on the foam due to exothermicity and oven

  8. Strengthening fairness, transparency and accountability in health care priority setting at district level in Tanzania

    Directory of Open Access Journals (Sweden)

    Stephen Maluka

    2011-11-01

    Full Text Available Health care systems are faced with the challenge of resource scarcity and have insufficient resources to respond to all health problems and target groups simultaneously. Hence, priority setting is an inevitable aspect of every health system. However, priority setting is complex and difficult because the process is frequently influenced by political, institutional and managerial factors that are not considered by conventional priority-setting tools. In a five-year EU-supported project, which started in 2006, ways of strengthening fairness and accountability in priority setting in district health management were studied. This review is based on a PhD thesis that aimed to analyse health care organisation and management systems, and explore the potential and challenges of implementing Accountability for Reasonableness (A4R approach to priority setting in Tanzania. A qualitative case study in Mbarali district formed the basis of exploring the sociopolitical and institutional contexts within which health care decision making takes place. The study also explores how the A4R intervention was shaped, enabled and constrained by the contexts. Key informant interviews were conducted. Relevant documents were also gathered and group priority-setting processes in the district were observed. The study revealed that, despite the obvious national rhetoric on decentralisation, actual practice in the district involved little community participation. The assumption that devolution to local government promotes transparency, accountability and community participation, is far from reality. The study also found that while the A4R approach was perceived to be helpful in strengthening transparency, accountability and stakeholder engagement, integrating the innovation into the district health system was challenging. This study underscores the idea that greater involvement and accountability among local actors may increase the legitimacy and fairness of priority-setting

  9. ‘Sampling the reference set’ revisited

    NARCIS (Netherlands)

    Berkum, van E.E.M.; Linssen, H.N.; Overdijk, D.A.

    1998-01-01

    The confidence level of an inference table is defined as a weighted truth probability of the inference when sampling the reference set. The reference set is recognized by conditioning on the values of maximal partially ancillary statistics. In the sampling experiment values of incidental parameters

  10. A two-level strategy to realize life-cycle production optimization in an operational setting

    NARCIS (Netherlands)

    Essen, van G.M.; Hof, Van den P.M.J.; Jansen, J.D.

    2012-01-01

    We present a two-level strategy to improve robustness against uncertainty and model errors in life-cycle flooding optimization. At the upper level, a physics-based large-scale reservoir model is used to determine optimal life-cycle injection and production profiles. At the lower level these profiles

  11. A two-level strategy to realize life-cycle production optimization in an operational setting

    NARCIS (Netherlands)

    Essen, van G.M.; Hof, Van den P.M.J.; Jansen, J.D.

    2013-01-01

    We present a two-level strategy to improve robustness against uncertainty and model errors in life-cycle flooding optimization. At the upper level, a physics-based large-scale reservoir model is used to determine optimal life-cycle injection and production profiles. At the lower level these profiles

  12. SET overexpression in HEK293 cells regulates mitochondrial uncoupling proteins levels within a mitochondrial fission/reduced autophagic flux scenario

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Luciana O.; Goto, Renata N. [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Neto, Marinaldo P.C. [Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Sousa, Lucas O. [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Curti, Carlos [Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Leopoldino, Andréia M., E-mail: andreiaml@usp.br [Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil)

    2015-03-06

    We hypothesized that SET, a protein accumulated in some cancer types and Alzheimer disease, is involved in cell death through mitochondrial mechanisms. We addressed the mRNA and protein levels of the mitochondrial uncoupling proteins UCP1, UCP2 and UCP3 (S and L isoforms) by quantitative real-time PCR and immunofluorescence as well as other mitochondrial involvements, in HEK293 cells overexpressing the SET protein (HEK293/SET), either in the presence or absence of oxidative stress induced by the pro-oxidant t-butyl hydroperoxide (t-BHP). SET overexpression in HEK293 cells decreased UCP1 and increased UCP2 and UCP3 (S/L) mRNA and protein levels, whilst also preventing lipid peroxidation and decreasing the content of cellular ATP. SET overexpression also (i) decreased the area of mitochondria and increased the number of organelles and lysosomes, (ii) increased mitochondrial fission, as demonstrated by increased FIS1 mRNA and FIS-1 protein levels, an apparent accumulation of DRP-1 protein, and an increase in the VDAC protein level, and (iii) reduced autophagic flux, as demonstrated by a decrease in LC3B lipidation (LC3B-II) in the presence of chloroquine. Therefore, SET overexpression in HEK293 cells promotes mitochondrial fission and reduces autophagic flux in apparent association with up-regulation of UCP2 and UCP3; this implies a potential involvement in cellular processes that are deregulated such as in Alzheimer's disease and cancer. - Highlights: • SET, UCPs and autophagy prevention are correlated. • SET action has mitochondrial involvement. • UCP2/3 may reduce ROS and prevent autophagy. • SET protects cell from ROS via UCP2/3.

  13. A variational approach to multi-phase motion of gas, liquid and solid based on the level set method

    Science.gov (United States)

    Yokoi, Kensuke

    2009-07-01

    We propose a simple and robust numerical algorithm to deal with multi-phase motion of gas, liquid and solid based on the level set method [S. Osher, J.A. Sethian, Front propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulation, J. Comput. Phys. 79 (1988) 12; M. Sussman, P. Smereka, S. Osher, A level set approach for capturing solution to incompressible two-phase flow, J. Comput. Phys. 114 (1994) 146; J.A. Sethian, Level Set Methods and Fast Marching Methods, Cambridge University Press, 1999; S. Osher, R. Fedkiw, Level Set Methods and Dynamics Implicit Surface, Applied Mathematical Sciences, vol. 153, Springer, 2003]. In Eulerian framework, to simulate interaction between a moving solid object and an interfacial flow, we need to define at least two functions (level set functions) to distinguish three materials. In such simulations, in general two functions overlap and/or disagree due to numerical errors such as numerical diffusion. In this paper, we resolved the problem using the idea of the active contour model [M. Kass, A. Witkin, D. Terzopoulos, Snakes: active contour models, International Journal of Computer Vision 1 (1988) 321; V. Caselles, R. Kimmel, G. Sapiro, Geodesic active contours, International Journal of Computer Vision 22 (1997) 61; G. Sapiro, Geometric Partial Differential Equations and Image Analysis, Cambridge University Press, 2001; R. Kimmel, Numerical Geometry of Images: Theory, Algorithms, and Applications, Springer-Verlag, 2003] introduced in the field of image processing.

  14. Computerized detection of multiple sclerosis candidate regions based on a level set method using an artificial neural network

    International Nuclear Information System (INIS)

    Kuwazuru, Junpei; Magome, Taiki; Arimura, Hidetaka; Yamashita, Yasuo; Oki, Masafumi; Toyofuku, Fukai; Kakeda, Shingo; Yamamoto, Daisuke

    2010-01-01

    Yamamoto et al. developed the system for computer-aided detection of multiple sclerosis (MS) candidate regions. In a level set method in their proposed method, they employed the constant threshold value for the edge indicator function related to a speed function of the level set method. However, it would be appropriate to adjust the threshold value to each MS candidate region, because the edge magnitudes in MS candidates differ from each other. Our purpose of this study was to develop a computerized detection of MS candidate regions in MR images based on a level set method using an artificial neural network (ANN). To adjust the threshold value for the edge indicator function in the level set method to each true positive (TP) and false positive (FP) region, we constructed the ANN. The ANN could provide the suitable threshold value for each candidate region in the proposed level set method so that TP regions can be segmented and FP regions can be removed. Our proposed method detected MS regions at a sensitivity of 82.1% with 0.204 FPs per slice and similarity index of MS candidate regions was 0.717 on average. (author)

  15. Comparing Panelists' Understanding of Standard Setting across Multiple Levels of an Alternate Science Assessment

    Science.gov (United States)

    Hansen, Mary A.; Lyon, Steven R.; Heh, Peter; Zigmond, Naomi

    2013-01-01

    Large-scale assessment programs, including alternate assessments based on alternate achievement standards (AA-AAS), must provide evidence of technical quality and validity. This study provides information about the technical quality of one AA-AAS by evaluating the standard setting for the science component. The assessment was designed to have…

  16. Analysis of data relative to the update of diagnostic reference levels in radiology and nuclear medicine. 2011-2012 review

    International Nuclear Information System (INIS)

    2014-01-01

    Applying the Order of 24 October 2011 on diagnostic reference levels, departments of radiology and nuclear medicine must send a sample of 'patient' dosimetric data to the IRSN each year. The results of the analysis of dosimetric data performed between the 1 January 2011 and the 31 December 2012 presented in this report should enable the authority to define the needs for updating regulations. Professional involvement in DRLs improved globally over the 2011-2012 period but is heterogeneous according to the imaging area considered. The participation of conventional radiology professionals is still low, with less than 30% against over 75% in CT and 85% in nuclear medicine. Data collection in pediatrics, considering all the fields of medical imaging, remains extremely limited. This shows almost no dose assessment for children by imaging departments, and has the effect of not allowing authorities to provide professionals with DRLs representative of pediatric practices. The analysis of radiology doses and nuclear medicine administered activities by IRSN shows an overall decrease of statistical indicators on which DRLs are indexed. These results lead to proposals for updating reference values for a large number of examinations. In addition to the analysis of data collected for examinations currently mentioned in regulatory texts, IRSN recommends to update DRLs in a more general way by changing the strategy for collecting and updating pediatric DRLs, by including interventional radiology - specialty in which the radiation protection presents a major challenge - by introducing a more ambitious indicator than the 75. percentile in conventional radiology and nuclear medicine - the 25. percentile statistical indicator, and by taking into account new technologies inducing additional exposures to the patient as CT-scan associated with the PET. (authors)

  17. Organizational factors related to low levels of sickness absence in a representative set of Swedish companies.

    Science.gov (United States)

    Stoetzer, Ulrich; Bergman, Peter; Aborg, Carl; Johansson, Gun; Ahlberg, Gunnel; Parmsund, Marianne; Svartengren, Magnus

    2014-01-01

    The aim of this qualitative study was to identify manageable organizational factors that could explain why some companies have low levels of sickness absence. There may be factors at company level that can be managed to influence levels of sickness absence, and promote health and a prosperous organization. 38 representative Swedish companies. The study included a total of 204 semi-structured interviews at 38 representative Swedish companies. Qualitative thematic analysis was applied to the interviews, primarily with managers, to indicate the organizational factors that characterize companies with low levels of sickness absence. The factors that were found to characterize companies with low levels of sickness absence concerned strategies and procedures for managing leadership, employee development, communication, employee participation and involvement, corporate values and visions, and employee health. The results may be useful in finding strategies and procedures to reduce levels of sickness absence and promote health. There is research at individual level on the reasons for sickness absence. This study tries to elevate the issue to an organizational level. The findings suggest that explicit strategies for managing certain organizational factors can reduce sickness absence and help companies to develop more health-promoting strategies.

  18. Dynamic-thresholding level set: a novel computer-aided volumetry method for liver tumors in hepatic CT images

    Science.gov (United States)

    Cai, Wenli; Yoshida, Hiroyuki; Harris, Gordon J.

    2007-03-01

    Measurement of the volume of focal liver tumors, called liver tumor volumetry, is indispensable for assessing the growth of tumors and for monitoring the response of tumors to oncology treatments. Traditional edge models, such as the maximum gradient and zero-crossing methods, often fail to detect the accurate boundary of a fuzzy object such as a liver tumor. As a result, the computerized volumetry based on these edge models tends to differ from manual segmentation results performed by physicians. In this study, we developed a novel computerized volumetry method for fuzzy objects, called dynamic-thresholding level set (DT level set). An optimal threshold value computed from a histogram tends to shift, relative to the theoretical threshold value obtained from a normal distribution model, toward a smaller region in the histogram. We thus designed a mobile shell structure, called a propagating shell, which is a thick region encompassing the level set front. The optimal threshold calculated from the histogram of the shell drives the level set front toward the boundary of a liver tumor. When the volume ratio between the object and the background in the shell approaches one, the optimal threshold value best fits the theoretical threshold value and the shell stops propagating. Application of the DT level set to 26 hepatic CT cases with 63 biopsy-confirmed hepatocellular carcinomas (HCCs) and metastases showed that the computer measured volumes were highly correlated with those of tumors measured manually by physicians. Our preliminary results showed that DT level set was effective and accurate in estimating the volumes of liver tumors detected in hepatic CT images.

  19. An Accurate Fire-Spread Algorithm in the Weather Research and Forecasting Model Using the Level-Set Method

    Science.gov (United States)

    Muñoz-Esparza, Domingo; Kosović, Branko; Jiménez, Pedro A.; Coen, Janice L.

    2018-04-01

    The level-set method is typically used to track and propagate the fire perimeter in wildland fire models. Herein, a high-order level-set method using fifth-order WENO scheme for the discretization of spatial derivatives and third-order explicit Runge-Kutta temporal integration is implemented within the Weather Research and Forecasting model wildland fire physics package, WRF-Fire. The algorithm includes solution of an additional partial differential equation for level-set reinitialization. The accuracy of the fire-front shape and rate of spread in uncoupled simulations is systematically analyzed. It is demonstrated that the common implementation used by level-set-based wildfire models yields to rate-of-spread errors in the range 10-35% for typical grid sizes (Δ = 12.5-100 m) and considerably underestimates fire area. Moreover, the amplitude of fire-front gradients in the presence of explicitly resolved turbulence features is systematically underestimated. In contrast, the new WRF-Fire algorithm results in rate-of-spread errors that are lower than 1% and that become nearly grid independent. Also, the underestimation of fire area at the sharp transition between the fire front and the lateral flanks is found to be reduced by a factor of ≈7. A hybrid-order level-set method with locally reduced artificial viscosity is proposed, which substantially alleviates the computational cost associated with high-order discretizations while preserving accuracy. Simulations of the Last Chance wildfire demonstrate additional benefits of high-order accurate level-set algorithms when dealing with complex fuel heterogeneities, enabling propagation across narrow fuel gaps and more accurate fire backing over the lee side of no fuel clusters.

  20. Analysis of data relative to the update of diagnostic reference levels in radiology and nuclear medicine. 2013-2015 review

    International Nuclear Information System (INIS)

    2016-11-01

    Applying the Order of 24 October 2011 on diagnostic reference levels, departments of radiology and nuclear medicine must send a sample of 'patient' dosimetric data to the IRSN each year. The results of the analysis of dosimetric data performed between the 1 January 2013 and the 31 December 2015 presented in this report should enable the authority to define the needs for updating regulation. This assessment takes place in a national and international context particularly rich and active since the last years. More than 20 years after the official introduction of the DRL concept by ICRP and the first regulation requirements at a European level, the good and the bad sides of the DRLs systems implemented by several countries, including France, has shown the necessity of complementary actions regarding some specific practices (pediatrics, interventional radiology). On one hand, from a national point of view, the current collection and analysis system is highly efficient for evaluation of practices in France and for DRL update ability. On the other hand, as an optimization implementation tool, regarding the lack of professionals involvement, the current system should not be considered as fully effective in radiology. However, when the professionals carry out DRL data collection and analysis, optimization actions are implemented for nearly all the cases. During the 2013-2015 period, professionals involvement in DRLs globally improved but is heterogeneous according to the imaging area considered. The participation of conventional radiology professionals is still low, with less than 30% against about 80% in CT and more than 85% in nuclear medicine. From a dosimetric point of view, the national analysis shows an overall decrease of statistical indicators in radiology, computed tomography and nuclear medicine on which DRLs are indexed. These results lead to proposals for updating reference values for a large number of examinations. In addition to the analysis of data collected

  1. A suggestion of reference data for flow distribution at ankle and foot level using quantitative 99Tc-HDP three-phase bone scintigraphy

    DEFF Research Database (Denmark)

    Tøndevold, Niklas; Reving, Sofie; Møller, Nette

    2012-01-01

    To determine reference intervals for quantitative 99mTc-hydroxymethylene diphosphonate (99mTc-HDP) three-phase bone scintigraphy regarding flow distribution at ankle and mid-foot level.......To determine reference intervals for quantitative 99mTc-hydroxymethylene diphosphonate (99mTc-HDP) three-phase bone scintigraphy regarding flow distribution at ankle and mid-foot level....

  2. On piecewise constant level-set (PCLS) methods for the identification of discontinuous parameters in ill-posed problems

    International Nuclear Information System (INIS)

    De Cezaro, A; Leitão, A; Tai, X-C

    2013-01-01

    We investigate level-set-type methods for solving ill-posed problems with discontinuous (piecewise constant) coefficients. The goal is to identify the level sets as well as the level values of an unknown parameter function on a model described by a nonlinear ill-posed operator equation. The PCLS approach is used here to parametrize the solution of a given operator equation in terms of a L 2 level-set function, i.e. the level-set function itself is assumed to be a piecewise constant function. Two distinct methods are proposed for computing stable solutions of the resulting ill-posed problem: the first is based on Tikhonov regularization, while the second is based on the augmented Lagrangian approach with total variation penalization. Classical regularization results (Engl H W et al 1996 Mathematics and its Applications (Dordrecht: Kluwer)) are derived for the Tikhonov method. On the other hand, for the augmented Lagrangian method, we succeed in proving the existence of (generalized) Lagrangian multipliers in the sense of (Rockafellar R T and Wets R J-B 1998 Grundlehren der Mathematischen Wissenschaften (Berlin: Springer)). Numerical experiments are performed for a 2D inverse potential problem (Hettlich F and Rundell W 1996 Inverse Problems 12 251–66), demonstrating the capabilities of both methods for solving this ill-posed problem in a stable way (complicated inclusions are recovered without any a priori geometrical information on the unknown parameter). (paper)

  3. Area-level risk factors for adverse birth outcomes: trends in urban and rural settings

    OpenAIRE

    Kent, Shia T; McClure, Leslie A; Zaitchik, Ben F; Gohlke, Julia M

    2013-01-01

    Background Significant and persistent racial and income disparities in birth outcomes exist in the US. The analyses in this manuscript examine whether adverse birth outcome time trends and associations between area-level variables and adverse birth outcomes differ by urban?rural status. Methods Alabama births records were merged with ZIP code-level census measures of race, poverty, and rurality. B-splines were used to determine long-term preterm birth (PTB) and low birth weight (LBW) trends b...

  4. Representing the Fuzzy improved risk graph for determination of optimized safety integrity level in industrial setting

    Directory of Open Access Journals (Sweden)

    Z. Qorbali

    2013-12-01

    .Conclusion: as a result of establishing the presented method, identical levels in conventional risk graph table are replaced with different sublevels that not only increases the accuracy in determining the SIL, but also elucidates the effective factor in improving the safety level and consequently saves time and cost significantly. The proposed technique has been employed to develop the SIL of Tehran Refinery ISOMAX Center. IRG and FIRG results have been compared to clarify the efficacy and importance of the proposed method

  5. Serum 25-hydroxyvitamin D Levels in Patients Referred to Clinical Laboratories in Various Parts of Mashhad- Northeastern Iran

    Directory of Open Access Journals (Sweden)

    Ali Akbar Shamsian

    2015-06-01

    Full Text Available Introduction: Vitamin D has an important role in maintaining human health. The main source of vitamin D production is skin exposure to sunlight. Accordingly with the spread of apartment life culture, growth of industrial cities and the increase of air pollution; vitamin D deficiency and its implications is an important factor in the appearance of debilitating diseases in different age categories (especially for children, adults and elderly people.   Materials and Methods: A retrospective cross-sectional study based on an objective was conducted on 1,110 patients who were selected randomly. These patients have been referred to “center of education culture and research” laboratories (2 laboratories and 8 specialized laboratories for vitamin D test in the city of Mashhad. And after conducting the study, the collected data was analyzed using SPSS 13 software.   Results: The prevalence of vitamin D deficiency in the population under study was 68.8%. Vitamin D levels were significantly lower in males in comparison with females (P

  6. Evidence of dose saving in routine CT practice using iterative reconstruction derived from a national diagnostic reference level survey.

    Science.gov (United States)

    Thomas, P; Hayton, A; Beveridge, T; Marks, P; Wallace, A

    2015-09-01

    To assess the influence and significance of the use of iterative reconstruction (IR) algorithms on patient dose in CT in Australia. We examined survey data submitted to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) National Diagnostic Reference Level Service (NDRLS) during 2013 and 2014. We compared median survey dose metrics with categorization by scan region and use of IR. The use of IR results in a reduction in volume CT dose index of between 17% and 44% and a reduction in dose-length product of between 14% and 34% depending on the specific scan region. The reduction was highly significant (p sum test) for all six scan regions included in the NDRLS. Overall, 69% (806/1167) of surveys included in the analysis used IR. The use of IR in CT is achieving dose savings of 20-30% in routine practice in Australia. IR appears to be widely used by participants in the ARPANSA NDRLS with approximately 70% of surveys submitted employing this technique. This study examines the impact of the use of IR on patient dose in CT on a national scale.

  7. Nordic working group for medical x-ray diagnostics: Diagnostic reference levels within xray diagnostics - experiences in the Nordic countries

    International Nuclear Information System (INIS)

    Leitz, W.; Groen, P.; Servomaa, A.; Einarsson, G.; Olerud, H.

    2003-01-01

    Medical x-ray diagnostics is one of the few applications of ionising radiation where people are irradiated on purpose. The strategy for radiation protection is also different compared to that in other areas that have the zero-alternative as its ultimate goal, meaning that no human beings at all are exposed in these practices. The focus in x-ray diagnostics concerning radiation protection is justification and optimisation. Optimisation implies that the examination is performed in such a way that the radiation dose is as small as possible without jeopardising the diagnostic security. X- ray diagnostics is a complex method where many technical parameters and methodology factors together are interacting in the determination of radiation dose and image quality. The optimisation process is not a simple and uncomplicated procedure, this difficulty is reflected in many international and national surveys showing a large spread of patient doses for one and the same type of examination. The concept diagnostic reference levels (DRL) has been introduced as a tool for reducing this wide distribution that is obviously indicating a lack of optimisation, and for cutting the highest radiation doses. In this presentation the concept for DRL and the experience gained in the Nordic countries with DRL are described. (orig.)

  8. Diagnostic reference levels for common computed tomography (CT) examinations: results from the first Nigerian nationwide dose survey.

    Science.gov (United States)

    Ekpo, Ernest U; Adejoh, Thomas; Akwo, Judith D; Emeka, Owujekwe C; Modu, Ali A; Abba, Mohammed; Adesina, Kudirat A; Omiyi, David O; Chiegwu, Uche H

    2018-01-29

    To explore doses from common adult computed tomography (CT) examinations and propose national diagnostic reference levels (nDRLs) for Nigeria. This retrospective study was approved by the Nnamdi Azikiwe University and University Teaching Hospital Institutional Review Boards (IRB: NAUTH/CS/66/Vol8/84) and involved dose surveys of adult CT examinations across the six geographical regions of Nigeria and Abuja from January 2016 to August 2017. Dose data of adult head, chest and abdomen/pelvis CT examinations were extracted from patient folders. The median, 75th and 25th percentile CT dose index volume (CTDI vol ) and dose-length-product (DLP) were computed for each of these procedures. Effective doses (E) for these examinations were estimated using the k conversion factor as described in the ICRP publication 103 (E DLP  =  k × DLP ). The proposed 75th percentile CTDI vol for head, chest, and abdomen/pelvis are 61 mGy, 17 mGy, and 20 mGy, respectively. The corresponding DLPs are 1310 mGy.cm, 735 mGy.cm, and 1486 mGy.cm respectively. The effective doses were 2.75 mSv (head), 10.29 mSv (chest), and 22.29 mSv (abdomen/pelvis). Findings demonstrate wide dose variations within and across centres in Nigeria. The results also show CTDI vol comparable to international standards, but considerably higher DLP and effective doses.

  9. On the Level Set of a Function with Degenerate Minimum Point

    Directory of Open Access Journals (Sweden)

    Yasuhiko Kamiyama

    2015-01-01

    Full Text Available For n≥2, let M be an n-dimensional smooth closed manifold and f:M→R a smooth function. We set minf(M=m and assume that m is attained by unique point p∈M such that p is a nondegenerate critical point. Then the Morse lemma tells us that if a is slightly bigger than m, f-1(a is diffeomorphic to Sn-1. In this paper, we relax the condition on p from being nondegenerate to being an isolated critical point and obtain the same consequence. Some application to the topology of polygon spaces is also included.

  10. CUDA based Level Set Method for 3D Reconstruction of Fishes from Large Acoustic Data

    DEFF Research Database (Denmark)

    Sharma, Ojaswa; Anton, François

    2009-01-01

    Acoustic images present views of underwater dynamics, even in high depths. With multi-beam echo sounders (SONARs), it is possible to capture series of 2D high resolution acoustic images. 3D reconstruction of the water column and subsequent estimation of fish abundance and fish species identificat...... of suppressing threshold and show its convergence as the evolution proceeds. We also present a GPU based streaming computation of the method using NVIDIA's CUDA framework to handle large volume data-sets. Our implementation is optimised for memory usage to handle large volumes....

  11. Sci-Thur PM – Colourful Interactions: Highlights 07: Canadian Computed Tomography Survey: National Diagnostic Reference Levels

    Energy Technology Data Exchange (ETDEWEB)

    Wardlaw, Graeme M; Martel, Narine [Consumer & Clinical Radiation Protection Bureau / Health Canada (Canada)

    2016-08-15

    Purpose: The Canadian Computed (CT) Tomography Survey sought to collect CT technology and dose index data (CTDI and DLP) at the national level in order to establish national diagnostic reference levels (DRLs) for seven common CT examinations of standard-sized adults and pediatric patients. Methods: A single survey booklet (consisting of four sections) was mailed to and completed for each participating CT scanner. Survey sections collected data on (i) General facility and scanner information, (ii) routine protocols (as available), (iii) individual patient data (as applied) and (iv) manual CTDI measurements. Results: Dose index (CTDIvol and DLP) and associated patient data from 24 280 individual patient exam sequences was analyzed for seven common CT examinations performed in Canada: Adult Head, Chest, Abdomen/Pelvis, and Chest/Abdomen/Pelvis, and Pediatric Head, Chest, and Abdomen. Pediatric examination data was sub-divided into three age ranges: 0–3, 3–7 and 7–13 years. DRLs (75th percentile of dose index distributions) were found for all thirteen groups. Further analysis also permitted segmentation of examination data into 8 sub-groups, whose dose index data was displayed along with group histograms – showing relative contribution of axial vs. helical, contrast use (C+ vs. C-), and application of fixed current vs. dose reduction (DR) – 75th percentiles of DR sub-groups were, in almost all cases, lower than whole group (examination) DRLs. Conclusions: The analysis and summaries presented in the pending survey report can serve to aid local CT imaging optimization efforts within Canada and also contribute further to international efforts in radiation protection of patients.

  12. Wave energy level and geographic setting correlate with Florida beach water quality.

    Science.gov (United States)

    Feng, Zhixuan; Reniers, Ad; Haus, Brian K; Solo-Gabriele, Helena M; Kelly, Elizabeth A

    2016-03-15

    Many recreational beaches suffer from elevated levels of microorganisms, resulting in beach advisories and closures due to lack of compliance with Environmental Protection Agency guidelines. We conducted the first statewide beach water quality assessment by analyzing decadal records of fecal indicator bacteria (enterococci and fecal coliform) levels at 262 Florida beaches. The objectives were to depict synoptic patterns of beach water quality exceedance along the entire Florida shoreline and to evaluate their relationships with wave condition and geographic location. Percent exceedances based on enterococci and fecal coliform were negatively correlated with both long-term mean wave energy and beach slope. Also, Gulf of Mexico beaches exceeded the thresholds significantly more than Atlantic Ocean ones, perhaps partially due to the lower wave energy. A possible linkage between wave energy level and water quality is beach sand, a pervasive nonpoint source that tends to harbor more bacteria in the low-wave-energy environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Area-level risk factors for adverse birth outcomes: trends in urban and rural settings.

    Science.gov (United States)

    Kent, Shia T; McClure, Leslie A; Zaitchik, Ben F; Gohlke, Julia M

    2013-06-10

    Significant and persistent racial and income disparities in birth outcomes exist in the US. The analyses in this manuscript examine whether adverse birth outcome time trends and associations between area-level variables and adverse birth outcomes differ by urban-rural status. Alabama births records were merged with ZIP code-level census measures of race, poverty, and rurality. B-splines were used to determine long-term preterm birth (PTB) and low birth weight (LBW) trends by rurality. Logistic regression models were used to examine differences in the relationships between ZIP code-level percent poverty or percent African-American with either PTB or LBW. Interactions with rurality were examined. Population dense areas had higher adverse birth outcome rates compared to other regions. For LBW, the disparity between population dense and other regions increased during the 1991-2005 time period, and the magnitude of the disparity was maintained through 2010. Overall PTB and LBW rates have decreased since 2006, except within isolated rural regions. The addition of individual-level socioeconomic or race risk factors greatly attenuated these geographical disparities, but isolated rural regions maintained increased odds of adverse birth outcomes. ZIP code-level percent poverty and percent African American both had significant relationships with adverse birth outcomes. Poverty associations remained significant in the most population-dense regions when models were adjusted for individual-level risk factors. Population dense urban areas have heightened rates of adverse birth outcomes. High-poverty African American areas have higher odds of adverse birth outcomes in urban versus rural regions. These results suggest there are urban-specific social or environmental factors increasing risk for adverse birth outcomes in underserved communities. On the other hand, trends in PTBs and LBWs suggest interventions that have decreased adverse birth outcomes elsewhere may not be reaching

  14. Order of 24 October 2011 related to diagnosis reference levels in radiology and nuclear medicine; Arrete du 24 octobre 2011 relatif aux niveaux de reference diagnostiques en radiologie et en medecine nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Grall, J.Y. [Ministere du travail, de l' emploi et de la sante, Direction generale de la sante, 14, avenue Duquesne, 75350 PARIS 07 SP (France)

    2012-01-14

    This order defines diagnosis reference levels for examinations exposing to the most common or irradiating ionizing radiations in the case of radiology and nuclear medicine. It also specifies the role of the person authorized to use nuclear medicine equipment, the role of the IRSN in collecting and analysing data. Doses are specified in appendix for different types of examinations

  15. County-Level Poverty Is Equally Associated with Unmet Health Care Needs in Rural and Urban Settings

    Science.gov (United States)

    Peterson, Lars E.; Litaker, David G.

    2010-01-01

    Context: Regional poverty is associated with reduced access to health care. Whether this relationship is equally strong in both rural and urban settings or is affected by the contextual and individual-level characteristics that distinguish these areas, is unclear. Purpose: Compare the association between regional poverty with self-reported unmet…

  16. The Daily Events and Emotions of Master's-Level Family Therapy Trainees in Off-Campus Practicum Settings

    Science.gov (United States)

    Edwards, Todd M.; Patterson, Jo Ellen

    2012-01-01

    The Day Reconstruction Method (DRM) was used to assess the daily events and emotions of one program's master's-level family therapy trainees in off-campus practicum settings. This study examines the DRM reports of 35 family therapy trainees in the second year of their master's program in marriage and family therapy. Four themes emerged from the…

  17. Activity Sets in Multi-Organizational Ecologies : A Project-Level Perspective on Sustainable Energy Innovations

    NARCIS (Netherlands)

    Gerrit Willem Ziggers; Kristina Manser; Bas Hillebrand; Paul Driessen; Josée Bloemer

    2014-01-01

    Complex innovations involve multi-organizational ecologies consisting of a myriad of different actors. This study investigates how innovation activities can be interpreted in the context of multi-organizational ecologies. Taking a project-level perspective, this study proposes a typology of four

  18. Supporting Diverse Young Adolescents: Cooperative Grouping in Inclusive Middle-Level Settings

    Science.gov (United States)

    Miller, Nicole C.; McKissick, Bethany R.; Ivy, Jessica T.; Moser, Kelly

    2017-01-01

    The middle level classroom presents unique challenges to educators who strive to provide opportunities that acknowledge learner diversity in terms of social, cognitive, physical, and emotional development. This is confounded even further within inclusive middle-school classrooms where the responsibility to differentiate instruction is even more…

  19. Flipping for success: evaluating the effectiveness of a novel teaching approach in a graduate level setting

    OpenAIRE

    Moraros, John; Islam, Adiba; Yu, Stan; Banow, Ryan; Schindelka, Barbara

    2015-01-01

    Background Flipped Classroom is a model that?s quickly gaining recognition as a novel teaching approach among health science curricula. The purpose of this study was four-fold and aimed to compare Flipped Classroom effectiveness ratings with: 1) student socio-demographic characteristics, 2) student final grades, 3) student overall course satisfaction, and 4) course pre-Flipped Classroom effectiveness ratings. Methods The participants in the study consisted of 67 Masters-level graduate student...

  20. Stuttering Thoughts: Negative Self-Referent Thinking Is Less Sensitive to Aversive Outcomes in People with Higher Levels of Depressive Symptoms.

    Science.gov (United States)

    Iijima, Yudai; Takano, Keisuke; Boddez, Yannick; Raes, Filip; Tanno, Yoshihiko

    2017-01-01

    Learning theories of depression have proposed that depressive cognitions, such as negative thoughts with reference to oneself, can develop through a reinforcement learning mechanism. This negative self-reference is considered to be positively reinforced by rewarding experiences such as genuine support from others after negative self-disclosure, and negatively reinforced by avoidance of potential aversive situations. The learning account additionally predicts that negative self-reference would be maintained by an inability to adjust one's behavior when negative self-reference no longer leads to such reward. To test this prediction, we designed an adapted version of the reversal-learning task. In this task, participants were reinforced to choose and engage in either negative or positive self-reference by probabilistic economic reward and punishment. Although participants were initially trained to choose negative self-reference, the stimulus-reward contingencies were reversed to prompt a shift toward positive self-reference (Study 1) and a further shift toward negative self-reference (Study 2). Model-based computational analyses showed that depressive symptoms were associated with a low learning rate of negative self-reference, indicating a high level of reward expectancy for negative self-reference even after the contingency reversal. Furthermore, the difficulty in updating outcome predictions of negative self-reference was significantly associated with the extent to which one possesses negative self-images. These results suggest that difficulty in adjusting action-outcome estimates for negative self-reference increases the chance to be faced with negative aspects of self, which may result in depressive symptoms.

  1. Stuttering Thoughts: Negative Self-Referent Thinking Is Less Sensitive to Aversive Outcomes in People with Higher Levels of Depressive Symptoms

    Directory of Open Access Journals (Sweden)

    Yudai Iijima

    2017-08-01

    Full Text Available Learning theories of depression have proposed that depressive cognitions, such as negative thoughts with reference to oneself, can develop through a reinforcement learning mechanism. This negative self-reference is considered to be positively reinforced by rewarding experiences such as genuine support from others after negative self-disclosure, and negatively reinforced by avoidance of potential aversive situations. The learning account additionally predicts that negative self-reference would be maintained by an inability to adjust one’s behavior when negative self-reference no longer leads to such reward. To test this prediction, we designed an adapted version of the reversal-learning task. In this task, participants were reinforced to choose and engage in either negative or positive self-reference by probabilistic economic reward and punishment. Although participants were initially trained to choose negative self-reference, the stimulus-reward contingencies were reversed to prompt a shift toward positive self-reference (Study 1 and a further shift toward negative self-reference (Study 2. Model-based computational analyses showed that depressive symptoms were associated with a low learning rate of negative self-reference, indicating a high level of reward expectancy for negative self-reference even after the contingency reversal. Furthermore, the difficulty in updating outcome predictions of negative self-reference was significantly associated with the extent to which one possesses negative self-images. These results suggest that difficulty in adjusting action-outcome estimates for negative self-reference increases the chance to be faced with negative aspects of self, which may result in depressive symptoms.

  2. A highly efficient 3D level-set grain growth algorithm tailored for ccNUMA architecture

    Science.gov (United States)

    Mießen, C.; Velinov, N.; Gottstein, G.; Barrales-Mora, L. A.

    2017-12-01

    A highly efficient simulation model for 2D and 3D grain growth was developed based on the level-set method. The model introduces modern computational concepts to achieve excellent performance on parallel computer architectures. Strong scalability was measured on cache-coherent non-uniform memory access (ccNUMA) architectures. To achieve this, the proposed approach considers the application of local level-set functions at the grain level. Ideal and non-ideal grain growth was simulated in 3D with the objective to study the evolution of statistical representative volume elements in polycrystals. In addition, microstructure evolution in an anisotropic magnetic material affected by an external magnetic field was simulated.

  3. MO-FG-CAMPUS-IeP1-03: Establishment of Provincial Diagnostic Reference Levels in Pediatric Imaging

    International Nuclear Information System (INIS)

    Tonkopi, E; O’Brien, K

    2016-01-01

    Purpose: To establish provincial diagnostic reference levels (DRLs) in pediatric general radiography and computed tomography (CT) as a tool for the optimization of exposure parameters. Methods: Patient dose survey was conducted in the only pediatric hospital in the province of Nova Scotia. The DRLs were established as the 75th percentile of patient dose distributions in different age groups. For routine radiography projections the DRLs were determined in terms of entrance surface dose (ESD) calculated from the radiation output measurements and the tube current-exposure time product (mAs) recorded for each examination. Patient thickness was measured by the technologist during the examination. The CR and DR systems, employing respectively a fixed technique and phototiming, were evaluated separately; a two-tailed Student’s t-test was used to determine the significance of differences between the means of dose distributions. The CT studies included routine head, chest, abdomen/pelvis, and chest/abdomen/pelvis. The volume CT dose index (CTDIvol) and dose-length product (DLP) values were extracted retrospectively from PACS. The correction factors based on the effective diameter of the patient were applied to the CT dosimetry metrics based on the standard phantoms. Results: The provincial DRLs were established in the following age groups: newborn, 1, 5, 10, and 15 year olds. In general radiography the DR systems demonstrated slightly lower dose than the CR for all views, however the differences were not statistically significant (p > 0.05) for all examinations. In CT the provincial DRLs were lower than the published data, except for head DLPs in all age categories. This might be due to the small patient sample size in the survey. Future work will include additional CT data collection over an extended period of time. Conclusion: Provincial DRLs were established in the dedicated children’s hospital to provide guidance for the other facilities in examinations of pediatric

  4. Quality assurance in CT: implementation of the updated national diagnostic reference levels using an automated CT dose monitoring system.

    Science.gov (United States)

    Appel, E; Kröpil, P; Bethge, O T; Aissa, J; Thomas, C; Antoch, G; Boos, J

    2018-03-20

    To evaluate the implementation of the updated computed tomography (CT) diagnostic reference levels (DRLs) from the German Federal Office for Radiation Protection into clinical routine using an automatic CT dose monitoring system. CT radiation exposure was analysed before and after implementing the updated national DRLs into routine clinical work in 2016. After the implementation process, institutional CT protocols were mapped to the anatomical regions for which DRLs were provided. Systematically, protocols that exceeded the thresholds were optimised and analysed in detail. The CT radiation output parameters analysed were volumetric CT dose index (CTDIvol) and dose-length product (DLP). Three radiologists evaluated subjective image quality using a three-point Likert scale. The study included 94,258 CT series (from 27,103 CT examinations) in adult patients performed in 2016. When averaged over all body regions with available DRL, institutional CTDIvol/DLP values were always below the DRLs (65.2±32.9%/67.3±41.5% initially; 59.4±32%/60.5±39.9% after optimisation). Values exceeding the national DRLs were found for pelvis (n=268; CTDIvol 107.7±65.7%/DLP 106.3±79.3%), lumbar spine (n=91; 160.8±74.7%/175.2±104.1%), and facial bones (n=527; 108±39%/152.7±75.7%). After optimisation, CTDIvol and DLP were 87.9±73%/87.8±80.8% for the pelvis, 67.8±33.2%/74.5±50.6% for the lumbar spine and 95.1±45.8%/133.3±74.6% for the viscerocranium. An automatic CT dose monitoring system enabled not only comprehensive monitoring of a DRL implementation process but can also help to optimise radiation exposure. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  5. MO-FG-CAMPUS-IeP1-03: Establishment of Provincial Diagnostic Reference Levels in Pediatric Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tonkopi, E [Dalhousie University (Canada); Queen Elizabeth II Health Sciences Ctr (Canada); O’Brien, K [Dalhousie University (Canada); IWK Health Centre, Halifax, NS (Canada)

    2016-06-15

    Purpose: To establish provincial diagnostic reference levels (DRLs) in pediatric general radiography and computed tomography (CT) as a tool for the optimization of exposure parameters. Methods: Patient dose survey was conducted in the only pediatric hospital in the province of Nova Scotia. The DRLs were established as the 75th percentile of patient dose distributions in different age groups. For routine radiography projections the DRLs were determined in terms of entrance surface dose (ESD) calculated from the radiation output measurements and the tube current-exposure time product (mAs) recorded for each examination. Patient thickness was measured by the technologist during the examination. The CR and DR systems, employing respectively a fixed technique and phototiming, were evaluated separately; a two-tailed Student’s t-test was used to determine the significance of differences between the means of dose distributions. The CT studies included routine head, chest, abdomen/pelvis, and chest/abdomen/pelvis. The volume CT dose index (CTDIvol) and dose-length product (DLP) values were extracted retrospectively from PACS. The correction factors based on the effective diameter of the patient were applied to the CT dosimetry metrics based on the standard phantoms. Results: The provincial DRLs were established in the following age groups: newborn, 1, 5, 10, and 15 year olds. In general radiography the DR systems demonstrated slightly lower dose than the CR for all views, however the differences were not statistically significant (p > 0.05) for all examinations. In CT the provincial DRLs were lower than the published data, except for head DLPs in all age categories. This might be due to the small patient sample size in the survey. Future work will include additional CT data collection over an extended period of time. Conclusion: Provincial DRLs were established in the dedicated children’s hospital to provide guidance for the other facilities in examinations of pediatric

  6. Implementing and measuring the level of laboratory service integration in a program setting in Nigeria.

    Directory of Open Access Journals (Sweden)

    Henry Mbah

    Full Text Available The surge of donor funds to fight HIV&AIDS epidemic inadvertently resulted in the setup of laboratories as parallel structures to rapidly respond to the identified need. However these parallel structures are a threat to the existing fragile laboratory systems. Laboratory service integration is critical to remedy this situation. This paper describes an approach to quantitatively measure and track integration of HIV-related laboratory services into the mainstream laboratory services and highlight some key intervention steps taken, to enhance service integration.A quantitative before-and-after study conducted in 122 Family Health International (FHI360 supported health facilities across Nigeria. A minimum service package was identified including management structure; trainings; equipment utilization and maintenance; information, commodity and quality management for laboratory integration. A check list was used to assess facilities at baseline and 3 months follow-up. Level of integration was assessed on an ordinal scale (0 = no integration, 1 = partial integration, 2 = full integration for each service package. A composite score grading expressed as a percentage of total obtainable score of 14 was defined and used to classify facilities (≤ 80% FULL, 25% to 79% PARTIAL and <25% NO integration. Weaknesses were noted and addressed.We analyzed 9 (7.4% primary, 104 (85.2% secondary and 9 (7.4% tertiary level facilities. There were statistically significant differences in integration levels between baseline and 3 months follow-up period (p<0.01. Baseline median total integration score was 4 (IQR 3 to 5 compared to 7 (IQR 4 to 9 at 3 months follow-up (p = 0.000. Partial and fully integrated laboratory systems were 64 (52.5% and 0 (0.0% at baseline, compared to 100 (82.0% and 3 (2.4% respectively at 3 months follow-up (p = 0.000.This project showcases our novel approach to measure the status of each laboratory on the integration continuum.

  7. Job satisfaction in nurses working in tertiary level health care settings of Islamabad, Pakistan.

    Science.gov (United States)

    Bahalkani, Habib Akhtar; Kumar, Ramesh; Lakho, Abdul Rehman; Mahar, Benazir; Mazhar, Syeda Batool; Majeed, Abdul

    2011-01-01

    Job satisfaction greatly determines the productivity and efficiency of human resource for health. It literally means: 'the extent to which Health Professionals like or dislike their jobs'. Job satisfaction is said to be linked with employee's work environment, job responsibilities, and powers; and time pressure among various health professionals. As such it affects employee's organizational commitment and consequently the quality of health services. Objective of this study was to determine the level of job satisfaction and factors influencing it among nurses in a public sector hospital of Islamabad. A cross sectional study with self-administered structured questionnaire was conducted in the federal capital of Pakistan, Islamabad. Sample included 56 qualified nurses working in a tertiary care hospital. Overall 86% respondents were dissatisfied with about 26% highly dissatisfied with their job. The work environments, poor fringe benefits, dignity, responsibility given at workplace and time pressure were reason for dissatisfaction. Poor work environment, low salaries, lack of training opportunities, proper supervision, time pressure and financial rewards reported by the respondents. Our findings state a low level of overall satisfaction among workers in a public sector tertiary care health organization in Islamabad. Most of this dissatisfaction is caused by poor salaries, not given the due respect, poor work environment, unbalanced responsibilities with little overall control, time pressure, patient care and lack of opportunities for professional development.

  8. County-level poverty is equally associated with unmet health care needs in rural and urban settings.

    Science.gov (United States)

    Peterson, Lars E; Litaker, David G

    2010-01-01

    Regional poverty is associated with reduced access to health care. Whether this relationship is equally strong in both rural and urban settings or is affected by the contextual and individual-level characteristics that distinguish these areas, is unclear. Compare the association between regional poverty with self-reported unmet need, a marker of health care access, by rural/urban setting. Multilevel, cross-sectional analysis of a state-representative sample of 39,953 adults stratified by rural/urban status, linked at the county level to data describing contextual characteristics. Weighted random intercept models examined the independent association of regional poverty with unmet needs, controlling for a range of contextual and individual-level characteristics. The unadjusted association between regional poverty levels and unmet needs was similar in both rural (OR = 1.06 [95% CI, 1.04-1.08]) and urban (OR = 1.03 [1.02-1.05]) settings. Adjusting for other contextual characteristics increased the size of the association in both rural (OR = 1.11 [1.04-1.19]) and urban (OR = 1.11 [1.05-1.18]) settings. Further adjustment for individual characteristics had little additional effect in rural (OR = 1.10 [1.00-1.20]) or urban (OR = 1.11 [1.01-1.22]) settings. To better meet the health care needs of all Americans, health care systems in areas with high regional poverty should acknowledge the relationship between poverty and unmet health care needs. Investments, or other interventions, that reduce regional poverty may be useful strategies for improving health through better access to health care. © 2010 National Rural Health Association.

  9. Comparing of goal setting strategy with group education method to increase physical activity level: A randomized trial.

    Science.gov (United States)

    Jiryaee, Nasrin; Siadat, Zahra Dana; Zamani, Ahmadreza; Taleban, Roya

    2015-10-01

    Designing an intervention to increase physical activity is important to be based on the health care settings resources and be acceptable by the subject group. This study was designed to assess and compare the effect of the goal setting strategy with a group education method on increasing the physical activity of mothers of children aged 1 to 5. Mothers who had at least one child of 1-5 years were randomized into two groups. The effect of 1) goal-setting strategy and 2) group education method on increasing physical activity was assessed and compared 1 month and 3 months after the intervention. Also, the weight, height, body mass index (BMI), waist and hip circumference, and well-being were compared between the two groups before and after the intervention. Physical activity level increased significantly after the intervention in the goal-setting group and it was significantly different between the two groups after intervention (P goal-setting group after the intervention. In the group education method, only the well-being score improved significantly (P goal-setting strategy to boost physical activity, improving the state of well-being and decreasing BMI, waist, and hip circumference.

  10. Comparing of goal setting strategy with group education method to increase physical activity level: A randomized trial

    Directory of Open Access Journals (Sweden)

    Nasrin Jiryaee

    2015-01-01

    Full Text Available Background: Designing an intervention to increase physical activity is important to be based on the health care settings resources and be acceptable by the subject group. This study was designed to assess and compare the effect of the goal setting strategy with a group education method on increasing the physical activity of mothers of children aged 1 to 5. Materials and Methods: Mothers who had at least one child of 1-5 years were randomized into two groups. The effect of 1 goal-setting strategy and 2 group education method on increasing physical activity was assessed and compared 1 month and 3 months after the intervention. Also, the weight, height, body mass index (BMI, waist and hip circumference, and well-being were compared between the two groups before and after the intervention. Results: Physical activity level increased significantly after the intervention in the goal-setting group and it was significantly different between the two groups after intervention (P < 0.05. BMI, waist circumference, hip circumference, and well-being score were significantly different in the goal-setting group after the intervention. In the group education method, only the well-being score improved significantly (P < 0.05. Conclusion: Our study presented the effects of using the goal-setting strategy to boost physical activity, improving the state of well-being and decreasing BMI, waist, and hip circumference.

  11. A possible methodological approach to setting up control level of radiation factors

    International Nuclear Information System (INIS)

    Devyatajkin, E.V.; Abramov, Yu.V.

    1986-01-01

    The mathematical formalization of the concept of control levels (CL) which enables one to obtain CL numerical values of controllable parameters required for rapid control purposes is described. The initial data for the assessment of environmental radioactivity are the controllable parameter values that is practical characteristic of controllable radiation factor showing technically measurable or calculation value. The controllable parameters can be divided into two classes depending on the degree of radiation effect on a man: possessing additivity properties (dosimetric class) and non-possessing (radiation class, which comprises the results of control of medium alteration dynamics, equipment operation safety, completeness of protection measures performance). The CL calculation formulas with account for requirements of radiation safety standards (RSS-76) are presented

  12. High Levels of Post-Abortion Complication in a Setting Where Abortion Service Is Not Legalized

    Science.gov (United States)

    Melese, Tadele; Habte, Dereje; Tsima, Billy M.; Mogobe, Keitshokile Dintle; Chabaesele, Kesegofetse; Rankgoane, Goabaone; Keakabetse, Tshiamo R.; Masweu, Mabole; Mokotedi, Mosidi; Motana, Mpho; Moreri-Ntshabele, Badani

    2017-01-01

    Background Maternal mortality due to abortion complications stands among the three leading causes of maternal death in Botswana where there is a restrictive abortion law. This study aimed at assessing the patterns and determinants of post-abortion complications. Methods A retrospective institution based cross-sectional study was conducted at four hospitals from January to August 2014. Data were extracted from patients’ records with regards to their socio-demographic variables, abortion complications and length of hospital stay. Descriptive statistics and bivariate analysis were employed. Result A total of 619 patients’ records were reviewed with a mean (SD) age of 27.12 (5.97) years. The majority of abortions (95.5%) were reported to be spontaneous and 3.9% of the abortions were induced by the patient. Two thirds of the patients were admitted as their first visit to the hospitals and one third were referrals from other health facilities. Two thirds of the patients were admitted as a result of incomplete abortion followed by inevitable abortion (16.8%). Offensive vaginal discharge (17.9%), tender uterus (11.3%), septic shock (3.9%) and pelvic peritonitis (2.4%) were among the physical findings recorded on admission. Clinically detectable anaemia evidenced by pallor was found to be the leading major complication in 193 (31.2%) of the cases followed by hypovolemic and septic shock 65 (10.5%). There were a total of 9 abortion related deaths with a case fatality rate of 1.5%. Self-induced abortion and delayed uterine evacuation of more than six hours were found to have significant association with post-abortion complications (p-values of 0.018 and 0.035 respectively). Conclusion Abortion related complications and deaths are high in our setting where abortion is illegal. Mechanisms need to be devised in the health facilities to evacuate the uterus in good time whenever it is indicated and to be equipped to handle the fatal complications. There is an indication for

  13. High Levels of Post-Abortion Complication in a Setting Where Abortion Service Is Not Legalized.

    Directory of Open Access Journals (Sweden)

    Tadele Melese

    Full Text Available Maternal mortality due to abortion complications stands among the three leading causes of maternal death in Botswana where there is a restrictive abortion law. This study aimed at assessing the patterns and determinants of post-abortion complications.A retrospective institution based cross-sectional study was conducted at four hospitals from January to August 2014. Data were extracted from patients' records with regards to their socio-demographic variables, abortion complications and length of hospital stay. Descriptive statistics and bivariate analysis were employed.A total of 619 patients' records were reviewed with a mean (SD age of 27.12 (5.97 years. The majority of abortions (95.5% were reported to be spontaneous and 3.9% of the abortions were induced by the patient. Two thirds of the patients were admitted as their first visit to the hospitals and one third were referrals from other health facilities. Two thirds of the patients were admitted as a result of incomplete abortion followed by inevitable abortion (16.8%. Offensive vaginal discharge (17.9%, tender uterus (11.3%, septic shock (3.9% and pelvic peritonitis (2.4% were among the physical findings recorded on admission. Clinically detectable anaemia evidenced by pallor was found to be the leading major complication in 193 (31.2% of the cases followed by hypovolemic and septic shock 65 (10.5%. There were a total of 9 abortion related deaths with a case fatality rate of 1.5%. Self-induced abortion and delayed uterine evacuation of more than six hours were found to have significant association with post-abortion complications (p-values of 0.018 and 0.035 respectively.Abortion related complications and deaths are high in our setting where abortion is illegal. Mechanisms need to be devised in the health facilities to evacuate the uterus in good time whenever it is indicated and to be equipped to handle the fatal complications. There is an indication for clinical audit on post-abortion care

  14. Biosphere modeling for safety assessment to high-level radioactive waste geological disposal. Application of reference biosphere methodology to safety assesment of geological disposal

    International Nuclear Information System (INIS)

    Baba, Tomoko; Ishihara, Yoshinao; Ishiguro, Katsuhiko; Suzuki, Yuji; Naito, Morimasa

    2000-01-01

    In the safety assessment of a high-level radioactive waste disposal system, it is required to estimate future radiological impacts on human beings. Consideration of living habits and the human environment in the future involves a large degree of uncertainty. To avoid endless speculation aimed at reducing such uncertainty, an approach is applied for identifying and justifying a 'reference biosphere' for use in safety assessment in Japan. considering a wide range of Japanese geological environments, saline specific reference biospheres' were developed using an approach consistent with the BIOMOVS II reference biosphere methodology. (author)

  15. Age- and Gender-Specific Reference Intervals for Fasting Blood Glucose and Lipid Levels in School Children Measured With Abbott Architect c8000 Chemistry Analyzer

    OpenAIRE

    Tamimi, Waleed; Albanyan, Esam; Altwaijri, Yasmin; Tamim, Hani; Alhussein, Fahad

    2012-01-01

    Reference intervals for pubertal characteristics are influenced by genetic, geographic, dietary and socioeconomic factors. Therefore, the aim of this study was to establish age-specific reference intervals of glucose and lipid levels among local school children. This was cross-sectional study, conducted among Saudi school children. Fasting blood samples were collected from 2149 children, 1138 (53%) boys and 1011 (47%) girls, aged 6 to 18 years old. Samples were analyzed on the Architect c8000...

  16. Analysis of the criteria used by the international commission on radiological protection (ICRP) to justify the setting of numerical reference values. Report No. 277

    International Nuclear Information System (INIS)

    Schieber, C.; Schneider, T.; Lochard, J.; Crouail, P.

    2005-05-01

    Following its Publication 60, ICRP has proposed nine reports specifying quantified values for dose constraints, action levels, etc. Some 25 values have been identified in all these publications. Since a few years, ICRP is preparing new recommendations in order to provide 'a more coherent and comprehensible system'. The objective of ICRP is to propose to select among the existing quantified values, a few values that could encompass all the other ones. These values are not intended to replace the currently recommended values which remain valid. In this perspective, IRSN has asked CEPN to make a review of all the values introduced in the ICRP publications in order to obtain a broad view of the rationalities proposed by ICRP in the determination of these values. The following Publications of ICRP have been reviewed: - ICRP 60 - 1990 - 1990 Recommendations of ICRP, - ICRP 62 - 1992 - Radiological protection in biomedical research, - ICRP 63 - 1992 - Principles for intervention for protection of the public in a radiological emergency, - ICRP 64 - 1993 - Protection from potential exposure: a conceptual framework, - ICRP 65 - 1993 - Protection against radon-222 at home and at work, - ICRP 68 - 1994 - Dose coefficients for intakes of radionuclides by workers, - ICRP 75 - 1997 - General principles for the radiation protection of workers, - ICRP 77 - 1997 - Radiological protection policy for the disposal of radioactive waste, - ICRP 81 - 2000 - Radiation protection recommendations as applied to the disposal of long-lived solid radioactive waste, - ICRP 82 - 2000 - Protection of the public in situations of prolonged radiation exposure. The different quantitative values found in these publications are presented in this report, grouped by type of value: individual dose limits, 'maximum' individual dose, dose constraints, exemption, action and intervention levels. The rationalities proposed by ICRP for setting these values are presented, mainly based on the quotation of ICRP

  17. Setting up experimental incineration system for low-level radioactive samples and combustion experiments

    International Nuclear Information System (INIS)

    Yumoto, Yasuhiro; Hanafusa, Tadashi; Nagamatsu, Tomohiro; Okada, Shigeru

    1997-01-01

    An incineration system was constructed which were composed of a combustion furnace (AP-150R), a cyclone dust collector, radioisotope trapping and measurement apparatus and a radioisotope storage room built in the first basement of the Radioisotope Center. Low level radioactive samples (LLRS) used for the combustion experiment were composed of combustible material or semi-combustible material containing 500 kBq of 99m TcO 4 or 23.25 kBq of 131 INa. The distribution of radioisotopes both in the inside and outside of combustion furnace were estimated. We measured radioactivity of a smoke duct gas in terminal exit of the exhaust port. In case of combustion of LLRS containing 99m TcO 4 or 131 INa, concentration of radioisotopes at the exhaust port showed less than legal concentration limit of these radioisotopes. In cases of combustion of LLRS containing 99m TcO 4 or 131 INa, decontamination factors of the incineration system were 120 and 1.1, respectively. (author)

  18. Implementing and measuring the level of laboratory service integration in a program setting in Nigeria.

    Science.gov (United States)

    Mbah, Henry; Negedu-Momoh, Olubunmi Ruth; Adedokun, Oluwasanmi; Ikani, Patrick Anibbe; Balogun, Oluseyi; Sanwo, Olusola; Ochei, Kingsley; Ekanem, Maurice; Torpey, Kwasi

    2014-01-01

    The surge of donor funds to fight HIV&AIDS epidemic inadvertently resulted in the setup of laboratories as parallel structures to rapidly respond to the identified need. However these parallel structures are a threat to the existing fragile laboratory systems. Laboratory service integration is critical to remedy this situation. This paper describes an approach to quantitatively measure and track integration of HIV-related laboratory services into the mainstream laboratory services and highlight some key intervention steps taken, to enhance service integration. A quantitative before-and-after study conducted in 122 Family Health International (FHI360) supported health facilities across Nigeria. A minimum service package was identified including management structure; trainings; equipment utilization and maintenance; information, commodity and quality management for laboratory integration. A check list was used to assess facilities at baseline and 3 months follow-up. Level of integration was assessed on an ordinal scale (0 = no integration, 1 = partial integration, 2 = full integration) for each service package. A composite score grading expressed as a percentage of total obtainable score of 14 was defined and used to classify facilities (≤ 80% FULL, 25% to 79% PARTIAL and laboratory systems were 64 (52.5%) and 0 (0.0%) at baseline, compared to 100 (82.0%) and 3 (2.4%) respectively at 3 months follow-up (p = 0.000). This project showcases our novel approach to measure the status of each laboratory on the integration continuum.

  19. Three-Dimensional Simulation of DRIE Process Based on the Narrow Band Level Set and Monte Carlo Method

    Directory of Open Access Journals (Sweden)

    Jia-Cheng Yu

    2018-02-01

    Full Text Available A three-dimensional topography simulation of deep reactive ion etching (DRIE is developed based on the narrow band level set method for surface evolution and Monte Carlo method for flux distribution. The advanced level set method is implemented to simulate the time-related movements of etched surface. In the meanwhile, accelerated by ray tracing algorithm, the Monte Carlo method incorporates all dominant physical and chemical mechanisms such as ion-enhanced etching, ballistic transport, ion scattering, and sidewall passivation. The modified models of charged particles and neutral particles are epitomized to determine the contributions of etching rate. The effects such as scalloping effect and lag effect are investigated in simulations and experiments. Besides, the quantitative analyses are conducted to measure the simulation error. Finally, this simulator will be served as an accurate prediction tool for some MEMS fabrications.

  20. A topology optimization method based on the level set method for the design of negative permeability dielectric metamaterials

    DEFF Research Database (Denmark)

    Otomori, Masaki; Yamada, Takayuki; Izui, Kazuhiro

    2012-01-01

    This paper presents a level set-based topology optimization method for the design of negative permeability dielectric metamaterials. Metamaterials are artificial materials that display extraordinary physical properties that are unavailable with natural materials. The aim of the formulated...... optimization problem is to find optimized layouts of a dielectric material that achieve negative permeability. The presence of grayscale areas in the optimized configurations critically affects the performance of metamaterials, positively as well as negatively, but configurations that contain grayscale areas...... are highly impractical from an engineering and manufacturing point of view. Therefore, a topology optimization method that can obtain clear optimized configurations is desirable. Here, a level set-based topology optimization method incorporating a fictitious interface energy is applied to a negative...

  1. Quasi-min-max Fuzzy MPC of UTSG Water Level Based on Off-Line Invariant Set

    Science.gov (United States)

    Liu, Xiangjie; Jiang, Di; Lee, Kwang Y.

    2015-10-01

    In a nuclear power plant, the water level of the U-tube steam generator (UTSG) must be maintained within a safe range. Traditional control methods encounter difficulties due to the complexity, strong nonlinearity and “swell and shrink” effects, especially at low power levels. A properly designed robust model predictive control can well solve this problem. In this paper, a quasi-min-max fuzzy model predictive controller is developed for controlling the constrained UTSG system. While the online computational burden could be quite large for the real-time control, a bank of ellipsoid invariant sets together with the corresponding feedback control laws are obtained by off-line solving linear matrix inequalities (LMIs). Based on the UTSG states, the online optimization is simplified as a constrained optimization problem with a bisection search for the corresponding ellipsoid invariant set. Simulation results are given to show the effectiveness of the proposed controller.

  2. Creation of nuclear power stations for export. Adapting a reference power station from the technical level of a national programme

    International Nuclear Information System (INIS)

    Marcaillou, J.; Haond, H.; Py, J.P.

    1977-01-01

    The recent evolution of primary energy supplies places those countries with a nuclear industry in an exporting role. Exporting countries have generally developed a limited number of national reactor types and attempt to extend their manufacture with as few changes as possible. The EDF in France is implementing an important 900-MW(e) PWR programme based on Framatome nuclear reactors, initially conceived by Westinghouse. Standardization imposes constraints, has limits, but offers incontestable advantages in terms of reliability, availability and security. These advantages were highly appreciated during the introduction into service of conventional thermal loads. Importing countries are all concerned to purchase a proven model. However, various local restrictions are often present, which are usually different from those accounted for in the export model, thus resulting in a need for modification. The different ways of considering the inescapable constraints can be analysed and their influence on the 'disfigurement' of the reactor model can be examined. Some of these constraints are connected with characteristics of the site. The nature of the soil and the seismicity influence the foundation and the depth of the installation and the choice between a foundation on antiseismic supports or structural reinforcement. The hydrology (risk of flooding or of deviation of the cold source) influences the choice between elevation of the installation and a protective dike, and also the stand-by coolant circuit. The atmospheric conditions and the temperature of cooling water influence the materials and their conditioning as well as the power level of the station. The surrounding demography influences the waste treatment systems. The characteristics of the electricity network influence the plan of the electric power supply and the conditions of operation. Finally, the characteristics of the personnel of the undertaking provide training problems. Other parameters to be taken into

  3. Phenotypic and genotypic characteristics of carbapenem-resistant Enterobacteriaceae in a tertiary-level reference hospital in Turkey.

    Science.gov (United States)

    Baran, Irmak; Aksu, Neriman

    2016-04-06

    Enterobacteriaceae are among the most common pathogens that are responsible for serious community-acquired, hospital-acquired, and health-care associated infections. The emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE) have become an increasing concern for healthcare services worldwide. Infections caused by these bacteria have been associated with significant morbidity and mortality and treatment options have been limited. The rapid and accurate detection of carbapenem resistance in these bacteria is important for infection control. The aim of this study was to investigate the phenotypic and genotypic features of CRE strains isolated in a tertiary-level reference hospital in Turkey. A total of 181 CRE strains were included in the study. Antimicrobial susceptibility rates were tested using Vitek 2 system. Modified Hodge test (MHT) was performed using meropenem and ertapenem discs. Metallo-β-lactamase antimicrobial gradient test (E-test MBL strips) were used for evaluation of metallo-β-lactamase production. A multiplex PCR was used for detection of carbapenems resistance genes (IMP, VIM, KPC, NDM-1 and OXA-48). The OXA-48 gene was detected in 86 strains, NDM-1 gene in six strains, VIM gene in one strain. IMP and KPC genes were not identified. Three strains produced both OXA-48 and NDM-1 and one strain produced both OXA-48 and VIM. In two patients more than one genus of OXA-48 positive CREs was isolated. Ninety-two of the isolates were multidrug-resistant. One hundred and ten isolates were MHT with meropenem (MEM-MHT) positive and 109 isolates were MHT with ertapenem (ERT-MHT) positive. Nine of the isolates were positive with E-test MBL strips. The sensitivity of MEM-MHT and ERT-MHT for detection of OXA-48 was 70.9 and 70.6 %, respectively. MEM-MHT was found highly discriminative for OXA-48 Escherichia coli (p Enterobacteriaceae in the hospital environment. While OXA-48 is still the most common source of carbapenem resistance in

  4. Computed Tomography (CT) radiation dose in children: A survey to propose regional diagnostic reference levels in Greater Accra-Ghana

    International Nuclear Information System (INIS)

    Addo, Patience

    2016-07-01

    The aim of this work was to assess the doses delivered to paediatric patients during computed tomography (CT) examinations of the head, chest and abdomen, and establishing regional diagnostic reference levels (RDRLs) for four age groups. The patient data, technique parameters and dose descriptors collected include: age, sex, tube voltage, tube current, rotation time, slice thickness, scan length, volume CT dose index (CTDI_v_o_l) and dose length product (DLP). Currently, paediatric CT examinations account for 11% of radiation exposure. For the paediatric age groups; < 1 year, (1-5 years), (6-10 years) and (11-15 years), the proposed RDRLs for head in terms of CTDI_v_o_l are (28, 38, 48 and 86 mGy) and in terms of DLP; (395, 487, 601, 1614 mGy cm) respectively. For Chest examinations, proposed RDRLs in terms of CTDI_v_o_l are (1 and 5 mGy) and in terms of DLP; (18 and 110 mGy cm) for age groups; < 1 year and (1-5 years) respectively. For Abdomino-pelvic examinations, proposed RDRLs in terms of CTDI_v_o_l are (3, 3 and 10 mGy) and in terms of DLP; (71, 120 and 494 mGy cm) for age groups; < 1 year, (1-5 years) and (6-10 years) respectively. For abdomen examinations, proposed RDRLs in terms of CTDI_v_o_l are (3, 5 and 5 mGy) and in terms of DLP; (83, 124 and 233 mGy cm) for age groups; < 1 year, (1-5 years) and (11-15 years) respectively. RDRLs have been proposed for CTDI_v_o_l and DLP for head, chest, abdomen and Abdomino-pelvic paediatric CT examinations in this study. An optimisation is required for 11-15 years age group for the DLP values which was higher than their corresponding international DRLs. For an effective optimization of patient protection a trade-off between image quality and patients doses studies should be investigated. (au)

  5. Anthropometric Indicators in Children Referred to a Tertiary-level Public Health Care Institution from Buenos Aires, Argentina

    International Nuclear Information System (INIS)

    Janjetic, Mariana Andrea; Mantero, Paula; Zubillaga, Marcela Beatriz; Boccio, José; Goldman, Cinthia

    2014-01-01

    Full text: Introduction: Stunting is a multifactorial phenomenon with a high prevalence in developing countries. Helicobacter pylori, a bacterium that colonizes the gastric mucosa, has been related to growth impairment due to micronutrient malabsorption. However this hypothesis remains controversial. Objective: The aim of our work was to determine anthropometric indicators in children referred to a Tertiary-level Public Health Care Institution from Buenos Aires, Argentina, for upper gastrointestinal symptoms evaluation. Methods: 525 children (4-16 y) assisting to the Gastroenterology Unit of the Hospital de Niños “Sor María Ludovica”, La Plata, Argentina, were diagnosed for H. pylori infection by the 13C-Urea Breath Test. Weight and height were measured for calculation of anthropometric indicators height for age (HAZ), weight for age (WAZ) and Body Mass Index for age (BMI) using the Anthro Plus 2007 software of the World Health Organization. Statistical analysis was performed by Student’s t Test, Mann-Whitney Test and lineal regression. Results: Prevalence of H. pylori infection was 25.1% (95% CI, 21.5-29.5), with a mean age of the children similar in both groups, 10.1y (95% CI, 9.8-10.3y). Mean HAZ and WAZ were -0.40 (95% CI, -0.57-[-0.22]) and -0.31 (95% CI, -0.51-[-0.11]) in the positive group, and -0.18 (95% CI, -0.28-[-0.09]) and -0.10 (95% CI, -0.21-0.01) in the negative group. HAZ was significantly lower in the positive group (p = 0.04), while no significant differences were found for WAZ (p = 0.07) and BMI for age (p = 0.20) between both groups. However, after adjusting for confounding factors these differences were no longer significant. Stunting was found in 4.5% (95% CI, 2.1-9.6) and 3.3% (95% CI, 1.9-5.6) of the H. pylori positive and negative children respectively, while underweight was observed in 5.3% (95% CI, 2.6-10.5) and 6.7% (95% CI, 4.6-9.6) of the above mentioned groups. Conclusions: Prevalence of stunting and underweight were low in

  6. Numerical simulation of interface movement in gas-liquid two-phase flows with Level Set method

    International Nuclear Information System (INIS)

    Li Huixiong; Chinese Academy of Sciences, Beijing; Deng Sheng; Chen Tingkuan; Zhao Jianfu; Wang Fei

    2005-01-01

    Numerical simulation of gas-liquid two-phase flow and heat transfer has been an attractive work for a quite long time, but still remains as a knotty difficulty due to the inherent complexities of the gas-liquid two-phase flow resulted from the existence of moving interfaces with topology changes. This paper reports the effort and the latest advances that have been made by the authors, with special emphasis on the methods for computing solutions to the advection equation of the Level set function, which is utilized to capture the moving interfaces in gas-liquid two-phase flows. Three different schemes, i.e. the simple finite difference scheme, the Superbee-TVD scheme and the 5-order WENO scheme in combination with the Runge-Kutta method are respectively applied to solve the advection equation of the Level Set. A numerical procedure based on the well-verified SIMPLER method is employed to numerically calculate the momentum equations of the two-phase flow. The above-mentioned three schemes are employed to simulate the movement of four typical interfaces under 5 typical flowing conditions. Analysis of the numerical results shows that the 5-order WENO scheme and the Superbee-TVD scheme are much better than the simple finite difference scheme, and the 5-order WENO scheme is the best to compute solutions to the advection equation of the Level Set. The 5-order WENO scheme will be employed as the main scheme to get solutions to the advection equations of the Level Set when gas-liquid two-phase flows are numerically studied in the future. (authors)

  7. Individual and setting level predictors of the implementation of a skin cancer prevention program: a multilevel analysis

    Directory of Open Access Journals (Sweden)

    Brownson Ross C

    2010-05-01

    Full Text Available Abstract Background To achieve widespread cancer control, a better understanding is needed of the factors that contribute to successful implementation of effective skin cancer prevention interventions. This study assessed the relative contributions of individual- and setting-level characteristics to implementation of a widely disseminated skin cancer prevention program. Methods A multilevel analysis was conducted using data from the Pool Cool Diffusion Trial from 2004 and replicated with data from 2005. Implementation of Pool Cool by lifeguards was measured using a composite score (implementation variable, range 0 to 10 that assessed whether the lifeguard performed different components of the intervention. Predictors included lifeguard background characteristics, lifeguard sun protection-related attitudes and behaviors, pool characteristics, and enhanced (i.e., more technical assistance, tailored materials, and incentives are provided versus basic treatment group. Results The mean value of the implementation variable was 4 in both years (2004 and 2005; SD = 2 in 2004 and SD = 3 in 2005 indicating a moderate implementation for most lifeguards. Several individual-level (lifeguard characteristics and setting-level (pool characteristics and treatment group factors were found to be significantly associated with implementation of Pool Cool by lifeguards. All three lifeguard-level domains (lifeguard background characteristics, lifeguard sun protection-related attitudes and behaviors and six pool-level predictors (number of weekly pool visitors, intervention intensity, geographic latitude, pool location, sun safety and/or skin cancer prevention programs, and sun safety programs and policies were included in the final model. The most important predictors of implementation were the number of weekly pool visitors (inverse association and enhanced treatment group (positive association. That is, pools with fewer weekly visitors and pools in the enhanced

  8. Classification of Normal and Apoptotic Cells from Fluorescence Microscopy Images Using Generalized Polynomial Chaos and Level Set Function.

    Science.gov (United States)

    Du, Yuncheng; Budman, Hector M; Duever, Thomas A

    2016-06-01

    Accurate automated quantitative analysis of living cells based on fluorescence microscopy images can be very useful for fast evaluation of experimental outcomes and cell culture protocols. In this work, an algorithm is developed for fast differentiation of normal and apoptotic viable Chinese hamster ovary (CHO) cells. For effective segmentation of cell images, a stochastic segmentation algorithm is developed by combining a generalized polynomial chaos expansion with a level set function-based segmentation algorithm. This approach provides a probabilistic description of the segmented cellular regions along the boundary, from which it is possible to calculate morphological changes related to apoptosis, i.e., the curvature and length of a cell's boundary. These features are then used as inputs to a support vector machine (SVM) classifier that is trained to distinguish between normal and apoptotic viable states of CHO cell images. The use of morphological features obtained from the stochastic level set segmentation of cell images in combination with the trained SVM classifier is more efficient in terms of differentiation accuracy as compared with the original deterministic level set method.

  9. GPU accelerated edge-region based level set evolution constrained by 2D gray-scale histogram.

    Science.gov (United States)

    Balla-Arabé, Souleymane; Gao, Xinbo; Wang, Bin

    2013-07-01

    Due to its intrinsic nature which allows to easily handle complex shapes and topological changes, the level set method (LSM) has been widely used in image segmentation. Nevertheless, LSM is computationally expensive, which limits its applications in real-time systems. For this purpose, we propose a new level set algorithm, which uses simultaneously edge, region, and 2D histogram information in order to efficiently segment objects of interest in a given scene. The computational complexity of the proposed LSM is greatly reduced by using the highly parallelizable lattice Boltzmann method (LBM) with a body force to solve the level set equation (LSE). The body force is the link with image data and is defined from the proposed LSE. The proposed LSM is then implemented using an NVIDIA graphics processing units to fully take advantage of the LBM local nature. The new algorithm is effective, robust against noise, independent to the initial contour, fast, and highly parallelizable. The edge and region information enable to detect objects with and without edges, and the 2D histogram information enable the effectiveness of the method in a noisy environment. Experimental results on synthetic and real images demonstrate subjectively and objectively the performance of the proposed method.

  10. Comparison of different statistical methods for estimation of extreme sea levels with wave set-up contribution

    Science.gov (United States)

    Kergadallan, Xavier; Bernardara, Pietro; Benoit, Michel; Andreewsky, Marc; Weiss, Jérôme

    2013-04-01

    Estimating the probability of occurrence of extreme sea levels is a central issue for the protection of the coast. Return periods of sea level with wave set-up contribution are estimated here in one site : Cherbourg in France in the English Channel. The methodology follows two steps : the first one is computation of joint probability of simultaneous wave height and still sea level, the second one is interpretation of that joint probabilities to assess a sea level for a given return period. Two different approaches were evaluated to compute joint probability of simultaneous wave height and still sea level : the first one is multivariate extreme values distributions of logistic type in which all components of the variables become large simultaneously, the second one is conditional approach for multivariate extreme values in which only one component of the variables have to be large. Two different methods were applied to estimate sea level with wave set-up contribution for a given return period : Monte-Carlo simulation in which estimation is more accurate but needs higher calculation time and classical ocean engineering design contours of type inverse-FORM in which the method is simpler and allows more complex estimation of wave setup part (wave propagation to the coast for example). We compare results from the two different approaches with the two different methods. To be able to use both Monte-Carlo simulation and design contours methods, wave setup is estimated with an simple empirical formula. We show advantages of the conditional approach compared to the multivariate extreme values approach when extreme sea-level occurs when either surge or wave height is large. We discuss the validity of the ocean engineering design contours method which is an alternative when computation of sea levels is too complex to use Monte-Carlo simulation method.

  11. Pulse Wave Velocity as Marker of Preclinical Arterial Disease: Reference Levels in a Uruguayan Population Considering Wave Detection Algorithms, Path Lengths, Aging, and Blood Pressure

    Directory of Open Access Journals (Sweden)

    Ignacio Farro

    2012-01-01

    Full Text Available Carotid-femoral pulse wave velocity (PWV has emerged as the gold standard for non-invasive evaluation of aortic stiffness; absence of standardized methodologies of study and lack of normal and reference values have limited a wider clinical implementation. This work was carried out in a Uruguayan (South American population in order to characterize normal, reference, and threshold levels of PWV considering normal age-related changes in PWV and the prevailing blood pressure level during the study. A conservative approach was used, and we excluded symptomatic subjects; subjects with history of cardiovascular (CV disease, diabetes mellitus or renal failure; subjects with traditional CV risk factors (other than age and gender; asymptomatic subjects with atherosclerotic plaques in carotid arteries; patients taking anti-hypertensives or lipid-lowering medications. The included subjects (n=429 were categorized according to the age decade and the blood pressure levels (at study time. All subjects represented the “reference population”; the group of subjects with optimal/normal blood pressures levels at study time represented the “normal population.” Results. Normal and reference PWV levels were obtained. Differences in PWV levels and aging-associated changes were obtained. The obtained data could be used to define vascular aging and abnormal or disease-related arterial changes.

  12. Reference binding energies of transition metal carbides by core-level x-ray photoelectron spectroscopy free from Ar+ etching artefacts

    Science.gov (United States)

    Greczynski, G.; Primetzhofer, D.; Hultman, L.

    2018-04-01

    We report x-ray photoelectron spectroscopy (XPS) core level binding energies (BE's) for the widely-applicable groups IVb-VIb transition metal carbides (TMCs) TiC, VC, CrC, ZrC, NbC, MoC, HfC, TaC, and WC. Thin film samples are grown in the same deposition system, by dc magnetron co-sputtering from graphite and respective elemental metal targets in Ar atmosphere. To remove surface contaminations resulting from exposure to air during sample transfer from the growth chamber into the XPS system, layers are either (i) Ar+ ion-etched or (ii) UHV-annealed in situ prior to XPS analyses. High resolution XPS spectra reveal that even gentle etching affects the shape of core level signals, as well as BE values, which are systematically offset by 0.2-0.5 eV towards lower BE. These destructive effects of Ar+ ion etch become more pronounced with increasing the metal atom mass due to an increasing carbon-to-metal sputter yield ratio. Systematic analysis reveals that for each row in the periodic table (3d, 4d, and 5d) C 1s BE increases from left to right indicative of a decreased charge transfer from TM to C atoms, hence bond weakening. Moreover, C 1s BE decreases linearly with increasing carbide/metal melting point ratio. Spectra reported here, acquired from a consistent set of samples in the same instrument, should serve as a reference for true deconvolution of complex XPS cases, including multinary carbides, nitrides, and carbonitrides.

  13. Single-step reinitialization and extending algorithms for level-set based multi-phase flow simulations

    Science.gov (United States)

    Fu, Lin; Hu, Xiangyu Y.; Adams, Nikolaus A.

    2017-12-01

    We propose efficient single-step formulations for reinitialization and extending algorithms, which are critical components of level-set based interface-tracking methods. The level-set field is reinitialized with a single-step (non iterative) "forward tracing" algorithm. A minimum set of cells is defined that describes the interface, and reinitialization employs only data from these cells. Fluid states are extrapolated or extended across the interface by a single-step "backward tracing" algorithm. Both algorithms, which are motivated by analogy to ray-tracing, avoid multiple block-boundary data exchanges that are inevitable for iterative reinitialization and extending approaches within a parallel-computing environment. The single-step algorithms are combined with a multi-resolution conservative sharp-interface method and validated by a wide range of benchmark test cases. We demonstrate that the proposed reinitialization method achieves second-order accuracy in conserving the volume of each phase. The interface location is invariant to reapplication of the single-step reinitialization. Generally, we observe smaller absolute errors than for standard iterative reinitialization on the same grid. The computational efficiency is higher than for the standard and typical high-order iterative reinitialization methods. We observe a 2- to 6-times efficiency improvement over the standard method for serial execution. The proposed single-step extending algorithm, which is commonly employed for assigning data to ghost cells with ghost-fluid or conservative interface interaction methods, shows about 10-times efficiency improvement over the standard method while maintaining same accuracy. Despite their simplicity, the proposed algorithms offer an efficient and robust alternative to iterative reinitialization and extending methods for level-set based multi-phase simulations.

  14. Bud development, flowering and fruit set of Moringa oleifera Lam. (Horseradish Tree as affected by various irrigation levels

    Directory of Open Access Journals (Sweden)

    Quintin Ernst Muhl

    2013-12-01

    Full Text Available Moringa oleifera is becoming increasingly popular as an industrial crop due to its multitude of useful attributes as water purifier, nutritional supplement and biofuel feedstock. Given its tolerance to sub-optimal growing conditions, most of the current and anticipated cultivation areas are in medium to low rainfall areas. This study aimed to assess the effect of various irrigation levels on floral initiation, flowering and fruit set. Three treatments namely, a 900 mm (900IT, 600 mm (600IT and 300 mm (300IT per annum irrigation treatment were administered through drip irrigation, simulating three total annual rainfall amounts. Individual inflorescences from each treatment were tagged during floral initiation and monitored throughout until fruit set. Flower bud initiation was highest at the 300IT and lowest at the 900IT for two consecutive growing seasons. Fruit set on the other hand, decreased with the decrease in irrigation treatment. Floral abortion, reduced pollen viability as well as moisture stress in the style were contributing factors to the reduction in fruiting/yield observed at the 300IT. Moderate water stress prior to floral initiation could stimulate flower initiation, however, this should be followed by sufficient irrigation to ensure good pollination, fruit set and yield.

  15. The criteria for setting the natural gas reference price for purposes of government take calculation; Os criterios para fixacao do preco de referencia do gas natural para fins de calculo das participacoes governamentais

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Flavio Augusto Pimentel de; Rosa, Renata Gualberto Cordeiro [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The Petroleum Law states that the concession contract will also have provisions regarding the government takes established by the bid tender. However, the criteria for calculating the value of Royalties are set forth in the Decree 2.705/98, enacted to set such criteria, taking into account the volumes of production and the reference prices for oil and natural gas. The following aspects are analyzed in this paper: the method for calculating the volumes subject to the impact of Royalties; definition of the reference price for natural gas, the general rule for setting up the reference price in case the sale was made at market price; the special rule in case the sale was not made on a market basis, in case there is no sale or in case of breach of the conditions set in that Decree; and the settlement of the reference price in situations where only part of the volumes produced are sold on contracts that meet the requirements of the Decree. In conclusion the problems caused by gaps in legislation will be highlighted, particularly with regard to concessions granted to consortia as well as the inconsistencies between the applicable legislation, which may provide different analysis, including by the ANP, according to the features of each case. (author)

  16. Improving district level health planning and priority setting in Tanzania through implementing accountability for reasonableness framework: Perceptions of stakeholders.

    Science.gov (United States)

    Maluka, Stephen; Kamuzora, Peter; San Sebastián, Miguel; Byskov, Jens; Ndawi, Benedict; Hurtig, Anna-Karin

    2010-12-01

    In 2006, researchers and decision-makers launched a five-year project - Response to Accountable Priority Setting for Trust in Health Systems (REACT) - to improve planning and priority-setting through implementing the Accountability for Reasonableness framework in Mbarali District, Tanzania. The objective of this paper is to explore the acceptability of Accountability for Reasonableness from the perspectives of the Council Health Management Team, local government officials, health workforce and members of user boards and committees. Individual interviews were carried out with different categories of actors and stakeholders in the district. The interview guide consisted of a series of questions, asking respondents to describe their perceptions regarding each condition of the Accountability for Reasonableness framework in terms of priority setting. Interviews were analysed using thematic framework analysis. Documentary data were used to support, verify and highlight the key issues that emerged. Almost all stakeholders viewed Accountability for Reasonableness as an important and feasible approach for improving priority-setting and health service delivery in their context. However, a few aspects of Accountability for Reasonableness were seen as too difficult to implement given the socio-political conditions and traditions in Tanzania. Respondents mentioned: budget ceilings and guidelines, low level of public awareness, unreliable and untimely funding, as well as the limited capacity of the district to generate local resources as the major contextual factors that hampered the full implementation of the framework in their context. This study was one of the first assessments of the applicability of Accountability for Reasonableness in health care priority-setting in Tanzania. The analysis, overall, suggests that the Accountability for Reasonableness framework could be an important tool for improving priority-setting processes in the contexts of resource-poor settings

  17. Analysis of carotid artery plaque and wall boundaries on CT images by using a semi-automatic method based on level set model

    International Nuclear Information System (INIS)

    Saba, Luca; Sannia, Stefano; Ledda, Giuseppe; Gao, Hao; Acharya, U.R.; Suri, Jasjit S.

    2012-01-01

    The purpose of this study was to evaluate the potentialities of a semi-automated technique in the detection and measurement of the carotid artery plaque. Twenty-two consecutive patients (18 males, 4 females; mean age 62 years) examined with MDCTA from January 2011 to March 2011 were included in this retrospective study. Carotid arteries are examined with a 16-multi-detector-row CT system, and for each patient, the most diseased carotid was selected. In the first phase, the carotid plaque was identified and one experienced radiologist manually traced the inner and outer boundaries by using polyline and radial distance method (PDM and RDM, respectively). In the second phase, the carotid inner and outer boundaries were traced with an automated algorithm: level-set-method (LSM). Data were compared by using Pearson rho correlation, Bland-Altman, and regression. A total of 715 slices were analyzed. The mean thickness of the plaque using the reference PDM was 1.86 mm whereas using the LSM-PDM was 1.96 mm; using the reference RDM was 2.06 mm whereas using the LSM-RDM was 2.03 mm. The correlation values between the references, the LSM, the PDM and the RDM were 0.8428, 0.9921, 0.745 and 0.6425. Bland-Altman demonstrated a very good agreement in particular with the RDM method. Results of our study indicate that LSM method can automatically measure the thickness of the plaque and that the best results are obtained with the RDM. Our results suggest that advanced computer-based algorithms can identify and trace the plaque boundaries like an experienced human reader. (orig.)

  18. Analysis of carotid artery plaque and wall boundaries on CT images by using a semi-automatic method based on level set model

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca; Sannia, Stefano; Ledda, Giuseppe [University of Cagliari - Azienda Ospedaliero Universitaria di Cagliari, Department of Radiology, Monserrato, Cagliari (Italy); Gao, Hao [University of Strathclyde, Signal Processing Centre for Excellence in Signal and Image Processing, Department of Electronic and Electrical Engineering, Glasgow (United Kingdom); Acharya, U.R. [Ngee Ann Polytechnic University, Department of Electronics and Computer Engineering, Clementi (Singapore); Suri, Jasjit S. [Biomedical Technologies Inc., Denver, CO (United States); Idaho State University (Aff.), Pocatello, ID (United States)

    2012-11-15

    The purpose of this study was to evaluate the potentialities of a semi-automated technique in the detection and measurement of the carotid artery plaque. Twenty-two consecutive patients (18 males, 4 females; mean age 62 years) examined with MDCTA from January 2011 to March 2011 were included in this retrospective study. Carotid arteries are examined with a 16-multi-detector-row CT system, and for each patient, the most diseased carotid was selected. In the first phase, the carotid plaque was identified and one experienced radiologist manually traced the inner and outer boundaries by using polyline and radial distance method (PDM and RDM, respectively). In the second phase, the carotid inner and outer boundaries were traced with an automated algorithm: level-set-method (LSM). Data were compared by using Pearson rho correlation, Bland-Altman, and regression. A total of 715 slices were analyzed. The mean thickness of the plaque using the reference PDM was 1.86 mm whereas using the LSM-PDM was 1.96 mm; using the reference RDM was 2.06 mm whereas using the LSM-RDM was 2.03 mm. The correlation values between the references, the LSM, the PDM and the RDM were 0.8428, 0.9921, 0.745 and 0.6425. Bland-Altman demonstrated a very good agreement in particular with the RDM method. Results of our study indicate that LSM method can automatically measure the thickness of the plaque and that the best results are obtained with the RDM. Our results suggest that advanced computer-based algorithms can identify and trace the plaque boundaries like an experienced human reader. (orig.)

  19. Age- and Gender-Specific Reference Intervals for Fasting Blood Glucose and Lipid Levels in School Children Measured With Abbott Architect c8000 Chemistry Analyzer.

    Science.gov (United States)

    Tamimi, Waleed; Albanyan, Esam; Altwaijri, Yasmin; Tamim, Hani; Alhussein, Fahad

    2012-04-01

    Reference intervals for pubertal characteristics are influenced by genetic, geographic, dietary and socioeconomic factors. Therefore, the aim of this study was to establish age-specific reference interva