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Sample records for die heissdampfreaktor-anlage hdr

  1. Hydrogen dressings HDR

    International Nuclear Information System (INIS)

    Rosiak, J.M.

    1990-01-01

    Within the past several years new developments in biomaterials have enabled a significant progress in the healing of different kinds of wounds. One of such biomaterials is synthetic hydrogels. They can be formed by means of radiation technology which gives some advantages over chemical methods. Hydrogel dressings HDR have the shape of transparent foil, 3-4 mm thick, which contain over 90% water. They can be used for healing exuding wounds and especially burns, ulcers, bedsores and skin grafts. HDR dressings are sterile, transparent and mechanically resistant

  2. HDR Efex Pro After the Shoot

    CERN Document Server

    Sholik, Stan

    2011-01-01

    A concise, on-the-go guide to the new HDR Efex Pro imaging toolkit for photographers Now that you've gone mobile and HDR, you want to be able to download and enhance your favorite photos on the run, without having to return to the mother ship (i.e., your desktop computer). This book shows you just how to do that using the amazing HDR Efex Pro, the image editing toolset from Nik Software. In brilliant color and using plenty of show-stopping examples, this practical guide explains all tools and features. Follow numbered steps and you'll soon be handling things like alignment, ghosting control, h

  3. HDR ühest kaadrist? / Janno Loide

    Index Scriptorium Estoniae

    Loide, Janno

    2008-01-01

    HDR-töötluse (High dynamic range - pildi kõrge dünaamiline ulatus) ja toonide kohandamise (tone mapping) meetodite kasutamisest pildi digitaalsel salvestusel ning sobiva hele-tumeduse leidmisel loodusfotode parema kvaliteedi saamiseks

  4. HDR-Aggregate Read Service (ARS)

    Data.gov (United States)

    Department of Veterans Affairs — ARS is a SOAP web service exposed over HTTPS that provides an aggregated (report) view of HTH Survey, DMP and Census data stored in the HDR DB. ARS is deployed in...

  5. HDR-Clinical Data Service (CDS)

    Data.gov (United States)

    Department of Veterans Affairs — CDS is a SOAP/REST web service interface that supports Create, Retrieve, Update, and Delete (CRUD) operations against HDR data stores over secure Hypertext Transfer...

  6. die rol van die unieverdedigingsmag in die onderdrukking van die

    African Journals Online (AJOL)

    agv regeringsoptrede nie.39. Siotsom. In die geskiedenis van die Unieverdedigings- mag word die gebeure random die 1914-staking oorskadu deur die Rebellie en Suid-Afrika se deelname aan die Eerste Wereldoorlog. Tog was dit 'n belangrike mylpaal in die geskiedenis van die organisasie, omdat dit sy eerste optrede ...

  7. Remote Afterloading High Dose Rate (HDR) Endobronchial Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hyesook; Choi, Eun Kyung; Yi, Byong Yong; Kim, Won Dong; Kim, Woo Sung; Koh, Youn Suck [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    1991-12-15

    Authors described the remote afterloading endobronchial brachytherapy (EBBT) technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were employed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT. One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient.

  8. Remote Afterloading High Dose Rate (HDR) Endobronchial Brachytherapy

    International Nuclear Information System (INIS)

    Chang, Hyesook; Choi, Eun Kyung; Yi, Byong Yong; Kim, Won Dong; Kim, Woo Sung; Koh, Youn Suck

    1991-01-01

    Authors described the remote afterloading endobronchial brachytherapy (EBBT) technique using the microSelectron HDR Ir-192 and the Asan Medical Center experience. Total 28 EBBT in 9 patients were performed since November 1989 and 24 EBBT in 8 patients were employed for palliation and 3 EBBT in 1 patient was treated curatively. Authors observed a significant relief of obstructive symptom with tumor regression in 7 patients out of 8 who were treated palliatively but one of them died of pulmonary congestion in 3 weeks after EBBT. One patient with prior therapy of extensive electrocautery expired within 1 day after 2nd EBBT procedure with massive hemorrhage from the lesion. EBBT procedure has been tolerable and can be performed as an outpatient

  9. Viewpoint adaptive display of HDR images

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Mantel, Claire

    2017-01-01

    In this paper viewpoint adaptive display of HDR images incorporating the effects of ambient light is presented and evaluated. LED backlight displays may render HDR images, but while at a global scale a high dynamic range may be achieved, locally the contrast is limited by the leakage of light...... through the LC elements of the display. To render high quality images, the display with backlight dimming can compute the values of the LED backlight and LC elements based on the input image, information about the viewpoint of the observer(s) and information of the ambient light. The goal is to achieve...... the best perceptual reproduction of the specified target image derived from the HDR input image in the specific viewing situation including multiple viewers, possibly having different preferences. An optimization based approach is presented. Some tests with reproduced images are also evaluated subjectively...

  10. Die binding van die konfessie

    Directory of Open Access Journals (Sweden)

    P. J. Coetzee

    1970-05-01

    Full Text Available Ons moet waak teen twee uiterstes. Aan die een kant het die dogma as onversoenlike vyand die dogmatisme en aan die ander kant die antidogmatisme — dit hou enersyds die gevaar in van verabsolutering (oorskatting, en ander- syds die gevaar van relativisme (onderskatting.

  11. Die Region braucht die Kultur - die Kultur braucht die Region

    OpenAIRE

    Klemm, Ulrich

    1995-01-01

    Die Region braucht die Kultur - die Kultur braucht die Region. - In: Region in Aktion - oder: Region im Abseits? - Boxberg-Wölchingen : Eigenständige Regionalentwicklung Baden-Württemberg, 1995. - S. 25 f.

  12. Die nabyheid van die Koninkryk

    Directory of Open Access Journals (Sweden)

    W.J. Snyman

    1963-03-01

    Full Text Available Vanweë die belangrikheid daarvan volg hier ’n breër bespreking van die proefskrif van dr. Tjaart van der Walt oor die nabyheid van die Koninkryk as wat in ’n gewone resensie kan geskied. Die vraagstuk wat onder oë gesien word is so oud as die kerk en die teologie, soms minder en soms meer op die voorgrond. Tans kan gesê word, staan dit in die middelpunt. Daarby is dit nie maar ’n akademiese vraagstuk nie, maar ’n vraagstuk waarvoor elke nadenkende leser van die Skrif te staan kom.

  13. Guidelines for optimization of planar HDR implants

    International Nuclear Information System (INIS)

    Zwicker, R.D.; Schmidt-Ullrich, R.

    1996-01-01

    Purpose: Conventional low dose rate (LDR) planar Ir-192 implants are typically carried out using at most a few different source strengths. Remote afterloading offers a much higher degree of flexibility with individually programmable dwell times. Dedicated software is available to generate individual dwell times producing isodose surfaces which contour as closely as possible the target volume. The success of these algorithms in enclosing the target volume while sparing normal tissues is dependent on the positioning of the source guides which constrain the dwell points. In this work we provide source placement guidelines for optimal coverage and dose uniformity in planar high dose rate (HDR) implants. The resulting distributions are compared with LDR treatments in terms of dose uniformity and early and late tissue effects. Materials and methods: Computer studies were undertaken to determine source positions and dwell times for optimal dose uniformity in planar HDR implants, and the results were compared to those obtained using corresponding LDR implant geometries. The improvements in the dose distributions achieved with the remote after loader are expected to help offset the increased late tissue effects which can occur when LDR irradiation is replaced with a few large HDR fractions. Equivalent differential volume-dose (DVD) curves for early and late effects were calculated for different numbers of HDR fractions using a linear-quadratic model and compared to the corresponding curves for the LDR regime. Results: Tables of source placement parameters were generated as guidelines for achieving highly homogeneous planar HDR dose distributions. Differential volume-dose data generated inside the target volume provide a quantitative measure of the improvement in real dose homogeneity obtained with remote afterloading. The net result is a shift of the peak in the DVD curve toward lower doses relative to the LDR implant. The equivalent DVD curves for late effects obtained

  14. Die topkwark

    Directory of Open Access Journals (Sweden)

    R. Tegen

    1998-07-01

    Full Text Available ’n Oorsig van die belangrikheid van die onlangs ontdekte topkwark by Fermilab in Chicago word gegee. Daar word aangetnon dat die topkwark belangrik is in fisika van die Oerknal, oftewel "Big Bang", en in die Standaard Model van Elementêredeeltjie-fisika. Toepaslike literatuur vir verdere studie kan van die lys van verwysings in hierdie kort, nietegniese artikel, nagegaan word.

  15. A JPEG backward-compatible HDR image compression

    Science.gov (United States)

    Korshunov, Pavel; Ebrahimi, Touradj

    2012-10-01

    High Dynamic Range (HDR) imaging is expected to become one of the technologies that could shape next generation of consumer digital photography. Manufacturers are rolling out cameras and displays capable of capturing and rendering HDR images. The popularity and full public adoption of HDR content is however hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of Low Dynamic Range (LDR) displays that are unable to render HDR. To facilitate wide spread of HDR usage, the backward compatibility of HDR technology with commonly used legacy image storage, rendering, and compression is necessary. Although many tone-mapping algorithms were developed for generating viewable LDR images from HDR content, there is no consensus on which algorithm to use and under which conditions. This paper, via a series of subjective evaluations, demonstrates the dependency of perceived quality of the tone-mapped LDR images on environmental parameters and image content. Based on the results of subjective tests, it proposes to extend JPEG file format, as the most popular image format, in a backward compatible manner to also deal with HDR pictures. To this end, the paper provides an architecture to achieve such backward compatibility with JPEG and demonstrates efficiency of a simple implementation of this framework when compared to the state of the art HDR image compression.

  16. Neodadjuvante und adjuvante Kurzzeit-Hormontherapie in Kombination mit konformaler HDR-Brachytherapie beim Prostatakarzinom

    Directory of Open Access Journals (Sweden)

    Martin T

    2004-01-01

    Full Text Available Zielsetzung: Auswertung der Behandlungsergebnisse der neoadjuvanten und adjuvanten Kurzzeit-Hormontherapie kombiniert mit konformaler HDR-Brachytherapie und externer Radiotherapie beim Prostatakarzinom. Patienten und Methoden: Von 01/97 bis 09/99 behandelten wir 102 Patienten mit Prostatakarzinomen im Stadium T1–3 N0 M0. Im Stadium T1–2 befanden sich 71, im Stadium T3 31 Patienten. Der mediane prätherapeutische PSA-Wert betrug 15,3 ng/ml. Nach ultraschallgesteuerter transrektaler Implantation von vier Afterloadingnadeln erfolgte die CT-gestützte 3D-Brachytherapie- Planung. Alle Patienten erhielten vier HDR-Implantate mit einer Referenzdosis von 5 Gy oder 7 Gy pro Implantat. Die Zeit zwischen jedem Implantat betrug jeweils 14 Tage. Nach der Brachytherapie folgte die externe Radiotherapie bis 39,6 Gy oder 45,0 Gy. Alle Patienten erhielten eine neoadjuvante und adjuvante Kurzzeit-Hormontherapie, die 2–19 Monate vor der Brachytherapie eingeleitet und 3 Monate nach Abschluß der externen Radiotherapie abgesetzt wurde (mediane Dauer: 9 Monate. Ergebnisse: Die mediane Nachbeobachtungszeit war 2,6 Jahre (range: 2,0–4,1 Jahre. Die biochemische Kontrollrate betrug 82 % nach 3 Jahren. Bei 14/102 Patienten registrierten wir ein biochemisches Rezidiv, bei 5/102 Patienten ein klinisches Rezidiv. Das Gesamtüberleben betrug 90 %, das krankheitsspezifische Überleben 98,0 % nach 3 Jahren. Ein Patient entwickelte eine prostato-urethro-rektale Fistel als späte Grad 4-Toxizität. Akute Grad-3 Toxizitäten traten bei 4 %, späte Grad-3 Toxizitäten bei 5 % der Patienten auf. Schlußfolgerung: Die neoadjuvante und adjuvante Kurzzeit-Hormontherapie kombiniert mit konformaler HDR-Brachytherapie und externer Radiotherapie erweist sich als sichere und wirksame Behandlungsmodalität beim Prostatakarzinom mit minimalen behandlungsbedingten Toxizitäten und einer vielversprechenden biochemischen Kontrollrate nach medianer Nachbeobachtungszeit von 2,6 Jahren.

  17. Observation and simulation of non-laminar flow phenomena at the HDR site near Soulth-sous-forets; Beobachtung und Simulation von nicht-laminarem Fliessverhalten am HDR-Standort Soultz

    Energy Technology Data Exchange (ETDEWEB)

    Kohl, T [ETH Hoenggerberg, Zuerich (Switzerland). Inst. fuer Geophysik; Evans, K F; Hopkirk, R J [Polydynamics Engineering, Maennedorf (Switzerland); Jung, R [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Rybach, L [ETH Hoenggerberg, Zuerich (Switzerland). Inst. fuer Geophysik und Radiometrie

    1997-12-01

    Three independent multi-rate flow experiments were conducted in 1994 and 1995 in the open hole depth interval of a wellbore at the Hot-Dry-Rocks (HDR) test site Soultz. The steady state and transient dowmhole pressure records gave clear indications of non-Darcian flow. A numerical model has been set-up to evaluate these two measurements. An excellent fit of the transient pressure responses of all three flow tests could be achieved by assuming a simple model geometry. The models predict fluid transport along a conduit with substantial surface area in which fully-turbulent flow is occurring. The parameters required by our best-fit simulation all fall into a physically reasonable range. Sensitivity analysis demonstrates a non-Darcian flow regime along highly conductive features. The existence of high capacity far-field faults as postulated in our model confirms earlier characterisations of the Soultz test site. (orig.) [Deutsch] In den Jahren 1994 und 1995 wurden drei unabhaengige Druck- bzw. Fliessratentests in den Bohrungen GPK1 und GPK2 des HDR Standortes Soultz durchgefuehrt. Sowohl die stationaeren wie auch die instationaeren Druckaufzeichnungen gaben bereits klare Hinweise auf nichtlaminare, turbulent-aehnliche Stroemungsverhaeltnisse. Zur genaueren Interpretation dieser Daten wurde das numerische Programm FRACTure erweitert. Unter der Annahme eines geometrisch einfachen Modells konnten die instationaeren Druckantworten sehr gut angepasst werden. Es gelang sogar, die beiden in GPK1 durchgefuehrten Tests durch dieselben Modelle zu erklaeren. Die hierfuer benoetigten Modellparameter liegen in einem physikalisch sinnvollem Rahmen und bestaetigen z.T. fruehere Untersuchungen. Die Existenz grosser Stoerungszonen, welche von den Modellen vorausgesetzt werden, bestaetigt ebenfalls fruehere Charakterisierungen des HDR Standortes Soultz als ein teilweise offenes hydraulisches System. (orig.)

  18. Additional androgen deprivation makes the difference. Biochemical recurrence-free survival in prostate cancer patients after HDR brachytherapy and external beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Schiffmann, Jonas; Tennstedt, Pierre; Beyer, Burkhard; Boehm, Katharina; Tilki, Derya; Salomon, Georg; Graefen, Markus [University Medical Center Hamburg-Eppendorf, Martini-Clinic Prostate Cancer Center, Hamburg (Germany); Lesmana, Hans; Platz, Volker; Petersen, Cordula; Kruell, Andreas; Schwarz, Rudolf [University Medical Center Hamburg-Eppendorf, Department of Radiation oncology, Hamburg (Germany)

    2015-04-01

    The role of additional androgen deprivation therapy (ADT) in prostate cancer (PCa) patients treated with combined HDR brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) is still unknown. Consecutive PCa patients classified as D'Amico intermediate and high-risk who underwent HDR-BT and EBRT treatment ± ADT at our institution between January 1999 and February 2009 were assessed. Multivariable Cox regression models predicting biochemical recurrence (BCR) were performed. BCR-free survival was assessed with Kaplan-Meier analyses. Overall, 392 patients were assessable. Of these, 221 (56.4 %) underwent trimodality (HDR-BT and EBRT and ADT) and 171 (43.6 %) bimodality (HDR-BT and EBRT) treatment. Additional ADT administration reduced the risk of BCR (HR: 0.4, 95 % CI: 0.3-0.7, p < 0.001). D'Amico high-risk patients had superior BCR-free survival when additional ADT was administered (log-rank p < 0.001). No significant difference for BCR-free survival was recorded when additional ADT was administered to D'Amico intermediate-risk patients (log-rank p = 0.2). Additional ADT administration improves biochemical control in D'Amico high-risk patients when HDR-BT and EBRT are combined. Physicians should consider the oncological benefit of ADT administration for these patients during the decision-making process. (orig.) [German] Der Nutzen einer zusaetzlichen Hormonentzugstherapie (ADT, ''androgen deprivation therapy'') fuer Patienten mit Prostatakarzinom (PCa), welche mit einer Kombination aus HDR-Brachytherapie (HDR-BT) und perkutaner Bestrahlung (EBRT) behandelt werden, ist weiterhin ungeklaert. Fuer diese Studie wurden konsekutive, nach der D'Amico-Risikoklassifizierung in ''intermediate'' und ''high-risk'' eingeteilte Patienten ausgewaehlt, die zwischen Januar 1999 und Februar 2009 in unserem Institut eine kombinierte Therapie aus HDR-BT, EBRT ± ADT erhalten haben. Eine

  19. MO-B-BRC-02: Ultrasound Based Prostate HDR

    International Nuclear Information System (INIS)

    Chang, Z.

    2016-01-01

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions

  20. MO-B-BRC-02: Ultrasound Based Prostate HDR

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Z. [Duke University Medical Center (United States)

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  1. MO-B-BRC-04: MRI-Based Prostate HDR

    International Nuclear Information System (INIS)

    Mourtada, F.

    2016-01-01

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions

  2. MO-B-BRC-03: CT-Based Prostate HDR

    International Nuclear Information System (INIS)

    Zoberi, J.

    2016-01-01

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions

  3. MO-B-BRC-04: MRI-Based Prostate HDR

    Energy Technology Data Exchange (ETDEWEB)

    Mourtada, F. [Christiana Care Hospital (United States)

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  4. MO-B-BRC-03: CT-Based Prostate HDR

    Energy Technology Data Exchange (ETDEWEB)

    Zoberi, J. [Washington University School of Medicine (United States)

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  5. A review of the HDR research programme

    International Nuclear Information System (INIS)

    Talja, H.; Koski, K.; Rintamaa, R.; Keskinen, R.

    1995-10-01

    In the German HDR (Heissdampfreaktor, hot steam reactor) reactor safety programme, experiments and simulating numerical analyses have been undertaken since 1976 to study the integrity and safety of light water reactors under operational and faulted conditions. The last experiments of the programme were conducted in 1991. The post test analyses have been finished by March 1994 and the last final reports were obtained a few months later. The report aims to inform the utilities and the regulatory body of Finland about the contents of the lokset HDR research programme and to consider the applicability of the results to safety analyses of Finnish nuclear power plants. The report centers around the thermal shock and piping component experiments within the last or third phase of the HDR programme. Investigations into severe reactor accidents, fire safety and non-destructive testing, also conducted during the third phase, are not considered. The report presents a review of the following experiment groups: E21 (crack growth under corrosive conditions, loading due to thermal stratification), E22 (leak rate and leak detection experiments of through-cracked piping), E23 (thermal transient and stratification experiments for a pipe nozzle), E31 (vibration of cracked piping due to blow down and closure of isolation valve), E32 (seismically induced vibrations of cracked piping), E33 (condensation phenomena in horizontal piping during emergency cooling). A comprehensive list of reference reports, received by VTT and containing a VTT more detailed description, is given for each experiment group. The review is focused on the loading conditions and their theoretical modelling. A comparison of theoretical and experimental results is presented for each experiment group. The safety margins are finally assessed with special reference to leak-before-break, a well known principle for assuring the integrity of primary circuit piping of nuclear power plants. (orig.) (71 figs., 5 tabs.)

  6. HDR economy with special reference to conditions in Europe

    International Nuclear Information System (INIS)

    Smolka, K.; Kappelmeyer, O.

    1992-01-01

    A cost benefit model for the economic evaluation of HDR energy production cost was developed. It can be used for systematic cost analyses of different components of a HDR plant. This relates to natural subsurface conditions (i.e., geothermal gradient, tectonic stress) as well as technical components (i.e., boreholes, heat/power conversion system). The model provides the limiting conditions for an economic HDR energy production. The economic model was applied for an evaluation of the natural parameters in the subsurface of Germany regarding their HDR-suitability. Within a site selection program in Europe the model is part of feasibility studies for the conceptual design of a HDR demonstration plant at three candidate sites: Bad Urach (Germany); Soultz-sous-Forets (France) and Cornwall (UK)

  7. HDR Image Quality Enhancement Based on Spatially Variant Retinal Response

    Directory of Open Access Journals (Sweden)

    Horiuchi Takahiko

    2010-01-01

    Full Text Available There is a growing demand for being able to display high dynamic range (HDR images on low dynamic range (LDR devices. Tone mapping is a process for enhancing HDR image quality on an LDR device by converting the tonal values of the original image from HDR to LDR. This paper proposes a new tone mapping algorithm for enhancing image quality by deriving a spatially-variant operator for imitating S-potential response in human retina, which efficiently improves local contrasts while conserving good global appearance. The proposed tone mapping operator is studied from a system construction point of view. It is found that the operator is regarded as a natural extension of the Retinex algorithm by adding a global adaptation process to the local adaptation. The feasibility of the proposed algorithm is examined in detail on experiments using standard HDR images and real HDR scene images, comparing with conventional tone mapping algorithms.

  8. Die funksie van die belydenis in die struktuur van die kerk en die ...

    African Journals Online (AJOL)

    Ter wille van die argument wat in hierdie voordrag na vore gebring word, word vier sodanige konstituerende elemente van die kerklike struktuur onderskei, te wete die belydenis, die teologie, die verkondi- ging (meer bepaald die prediking) en die kerkorde (kerkwet volgens ons terminologie). Ons gaan nou elkeen hiervan ...

  9. Die posisie van die Helper in die sending

    Directory of Open Access Journals (Sweden)

    I. J. van der Walt

    1972-05-01

    Full Text Available Gedurende die aanvangsjare van die sending het die helper ’n onmisbare funksie vervul. Hulle het die onherbergsame binnelande geken, waardevolle kontakpunte vir die sendelinge geopen en hulle mense geestelik help voorlig en voorberei.

  10. Color sensitivity of the multi-exposure HDR imaging process

    Science.gov (United States)

    Lenseigne, Boris; Jacobs, Valéry Ann; Withouck, Martijn; Hanselaer, Peter; Jonker, Pieter P.

    2013-04-01

    Multi-exposure high dynamic range(HDR) imaging builds HDR radiance maps by stitching together different views of a same scene with varying exposures. Practically, this process involves converting raw sensor data into low dynamic range (LDR) images, estimate the camera response curves, and use them in order to recover the irradiance for every pixel. During the export, applying white balance settings and image stitching, which both have an influence on the color balance in the final image. In this paper, we use a calibrated quasi-monochromatic light source, an integrating sphere, and a spectrograph in order to evaluate and compare the average spectral response of the image sensor. We finally draw some conclusion about the color consistency of HDR imaging and the additional steps necessary to use multi-exposure HDR imaging as a tool to measure the physical quantities such as radiance and luminance.

  11. Performance evaluation of objective quality metrics for HDR image compression

    Science.gov (United States)

    Valenzise, Giuseppe; De Simone, Francesca; Lauga, Paul; Dufaux, Frederic

    2014-09-01

    Due to the much larger luminance and contrast characteristics of high dynamic range (HDR) images, well-known objective quality metrics, widely used for the assessment of low dynamic range (LDR) content, cannot be directly applied to HDR images in order to predict their perceptual fidelity. To overcome this limitation, advanced fidelity metrics, such as the HDR-VDP, have been proposed to accurately predict visually significant differences. However, their complex calibration may make them difficult to use in practice. A simpler approach consists in computing arithmetic or structural fidelity metrics, such as PSNR and SSIM, on perceptually encoded luminance values but the performance of quality prediction in this case has not been clearly studied. In this paper, we aim at providing a better comprehension of the limits and the potentialities of this approach, by means of a subjective study. We compare the performance of HDR-VDP to that of PSNR and SSIM computed on perceptually encoded luminance values, when considering compressed HDR images. Our results show that these simpler metrics can be effectively employed to assess image fidelity for applications such as HDR image compression.

  12. DIE GESKIEDENIS VAN DIE PERSONEELFUNKSIE IN DIE SA ...

    African Journals Online (AJOL)

    stel (kortdiensstelsel). Met die uitbreek van die oorlog in 1939 het die. Unieverdedigingsmag uit 40% Staandemag en. 60% aktiewe Burgermag bestaan. Op 22 Sept. 1939 is magtiging aan die Aktiewe Burgermag- eenhede verleen om vrywilligers vir die duur van die oorlog te aanvaar. Agv beswaar dat die Verdedigingswet.

  13. Die Formatestadt

    OpenAIRE

    Günter Trojan

    2013-01-01

    Zu Zeiten von DV oder VHS (wer kennt das eigentlich noch?) war die Welt noch in Ordnung: Da hatte man eine Kassette in der Hand und wenn das passende Gerät gefunden wurde konnte man das Video auch abspielen. Günter Trojan diskutiert die Geschichte und Gegenwart unterschiedlicher Videoformate ...

  14. Die Formatestadt

    Directory of Open Access Journals (Sweden)

    Günter Trojan

    2013-06-01

    Full Text Available Zu Zeiten von DV oder VHS (wer kennt das eigentlich noch? war die Welt noch in Ordnung: Da hatte man eine Kassette in der Hand und wenn das passende Gerät gefunden wurde konnte man das Video auch abspielen. Günter Trojan diskutiert die Geschichte und Gegenwart unterschiedlicher Videoformate ...

  15. HDR video synthesis for vision systems in dynamic scenes

    Science.gov (United States)

    Shopovska, Ivana; Jovanov, Ljubomir; Goossens, Bart; Philips, Wilfried

    2016-09-01

    High dynamic range (HDR) image generation from a number of differently exposed low dynamic range (LDR) images has been extensively explored in the past few decades, and as a result of these efforts a large number of HDR synthesis methods have been proposed. Since HDR images are synthesized by combining well-exposed regions of the input images, one of the main challenges is dealing with camera or object motion. In this paper we propose a method for the synthesis of HDR video from a single camera using multiple, differently exposed video frames, with circularly alternating exposure times. One of the potential applications of the system is in driver assistance systems and autonomous vehicles, involving significant camera and object movement, non- uniform and temporally varying illumination, and the requirement of real-time performance. To achieve these goals simultaneously, we propose a HDR synthesis approach based on weighted averaging of aligned radiance maps. The computational complexity of high-quality optical flow methods for motion compensation is still pro- hibitively high for real-time applications. Instead, we rely on more efficient global projective transformations to solve camera movement, while moving objects are detected by thresholding the differences between the trans- formed and brightness adapted images in the set. To attain temporal consistency of the camera motion in the consecutive HDR frames, the parameters of the perspective transformation are stabilized over time by means of computationally efficient temporal filtering. We evaluated our results on several reference HDR videos, on synthetic scenes, and using 14-bit raw images taken with a standard camera.

  16. Interstitial prostate brachytherapy. LDR-PDR-HDR

    International Nuclear Information System (INIS)

    Kovacs, Gyoergy; Hoskin, Peter

    2013-01-01

    The first comprehensive overview of interstitial brachytherapy for the management of local or locally advanced prostate cancer. Written by an interdisciplinary team who have been responsible for the successful GEC-ESTRO/EAU Teaching Course. Discusses in detail patient selection, the results of different methods, the role of imaging, and medical physics issues. Prostate brachytherapy has been the subject of heated debate among surgeons and the proponents of the various brachytherapy methods. This very first interdisciplinary book on the subject provides a comprehensive overview of innovations in low dose rate (LDR), high dose rate (HDR), and pulsed dose rate (PDR) interstitial brachytherapy for the management of local or locally advanced prostate cancer. In addition to detailed chapters on patient selection and the use of imaging in diagnostics, treatment guidance, and implantation control, background chapters are included on related medical physics issues such as treatment planning and quality assurance. The results obtained with the different treatment options and the difficult task of salvage treatment are fully discussed. All chapters have been written by internationally recognized experts in their fields who for more than a decade have formed the teaching staff responsible for the successful GEC-ESTRO/EAU Prostate Brachytherapy Teaching Course. This book will be invaluable in informing residents and others of the scientific background and potential of modern prostate brachytherapy. It will also prove a useful source of up-to-date information for those who specialize in prostate brachytherapy or intend to start an interstitial brachytherapy service.

  17. Die funksie van die skeppingstradisie in die boek Jeremia

    African Journals Online (AJOL)

    gedeeites voor wat sterk ooreenkomste toon met die beskrywings van die skep pingsgebeure in die boek Jeremia. • Volgpns Von Rad (1957:144-146) het daar wel 'n groep bestaan wat belange ge- had liet by die oorlewering van die skeppingstradisies. Dit was waarskynlik die. Sadokitiese priesters wat om twee redes aan ...

  18. Die regsposisie van die gemolesteerde kind 1

    Directory of Open Access Journals (Sweden)

    P.J. Schabort

    1991-03-01

    Full Text Available Hoe reik die reg uit na die seksueel gemolesteerde kind? As na die reg in wye verband gekyk word, sou dit alie wetgewing en alle gemeneregsbeginsels en alle regsprosedures insluit waardeur die Staat poog om molestering te voorkom en die gemolesteerde kind in beskerming te neem. Dit le baie wyd en sou byvoorbeeld die maatreels insluit van die Kindenvet 33 van 1960; die Wet op Egskeiding 70 van 1979; die Wet op Kindersorg 74 van 1983; die Wet op die Status van Kinders 82 van 1987 en die Wet op Bemiddeling in Sekere Egskeidingsaangeleenthede 24 van 1987. Eersdaags sal dit moontlik ook ’n Manifes vir die Regte van Kinders insluit wat vermoedelik geskoei sal wees op die W O se Konvensie vir die Regte van die Kind (1989 w a arv an die RSA tan s nog nie ’n ondertekenaar is nie.

  19. TU-C-201-02: Clinical Implementation of HDR: Afterloader and Applicator Selection

    Energy Technology Data Exchange (ETDEWEB)

    Esthappan, J. [Washington University School of Medicine (United States)

    2015-06-15

    Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

  20. TU-C-201-00: Clinical Implementation of HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

  1. Traceable calibration of hospital 192Ir HDR sources

    International Nuclear Information System (INIS)

    Govinda Rajan, K.N.; Sharma, S.D.; Palaniselvam, T.; Vandana, S.; Bhatt, B.C.; Vinatha, S.; Patki, V.S.; Pendse, A.M.; Kannan, V.

    2004-01-01

    A HDR 1000 PLUS well type ionization chamber, procured from Standard Imaging, USA, and maintained by medical Physics and Safety Section (MPSS), Bhabha Atomic Research Centre (BARC), India, as a reference well chamber 1 (RWCH1), was traceably calibrated against the primary standard established by Radiological Standards Laboratory (RSL), BARC for 192 Ir HDR source, in terms of air kerma strength (AKS). An indigenously developed well-type ionization chamber, reference well chamber 2 (RWCH2) and electrometer system, fabricated by CD High Tech (CDHT) Instruments Private Ltd., Bangalore, India, was in turn calibrated against RWCH1. The CDHT system (i.e. RWCH2 and CDHT electrometer system) was taken to several hospitals, in different regions of the country, to check the calibration status of 192 Ir HDR sources. The result of this calibration audit work is reported here. (author)

  2. Evaluating HDR photos using Web 2.0 technology

    Science.gov (United States)

    Qiu, Guoping; Mei, Yujie; Duan, Jiang

    2011-01-01

    High dynamic range (HDR) photography is an emerging technology that has the potential to dramatically enhance the visual quality and realism of digital photos. One of the key technical challenges of HDR photography is displaying HDR photos on conventional devices through tone mapping or dynamic range compression. Although many different tone mapping techniques have been developed in recent years, evaluating tone mapping operators prove to be extremely difficult. Web2.0, social media and crowd-sourcing are emerging Internet technologies which can be harnessed to harvest the brain power of the mass to solve difficult problems in science, engineering and businesses. Paired comparison is used in the scientific study of preferences and attitudes and has been shown to be capable of obtaining an interval-scale ordering of items along a psychometric dimension such as preference or importance. In this paper, we exploit these technologies for evaluating HDR tone mapping algorithms. We have developed a Web2.0 style system that enables Internet users from anywhere to evaluate tone mapped HDR photos at any time. We adopt a simple paired comparison protocol, Internet users are presented a pair of tone mapped images and are simply asked to select the one that they think is better or click a "no difference" button. These user inputs are collected in the web server and analyzed by a rank aggregation algorithm which ranks the tone mapped photos according to the votes they received. We present experimental results which demonstrate that the emerging Internet technologies can be exploited as a new paradigm for evaluating HDR tone mapping algorithms. The advantages of this approach include the potential of collecting large user inputs under a variety of viewing environments rather than limited user participation under controlled laboratory environments thus enabling more robust and reliable quality assessment. We also present data analysis to correlate user generated qualitative

  3. Experience of the first application of HDR brachytherapy in nasopharynx

    International Nuclear Information System (INIS)

    Vega Hernandez, Manuel I.; Alfonso Laguardia, Rodolfo; Silvestre Patallo, Ileana; Roca Muchuli, Carlos; Garcia Heredia, Gilda

    2006-01-01

    A research was made by applying boost on the area of the nasopharynx relapse with high dose rate (HDR) in a diagnosis of nasopharynx carcinoma previously treated with telecobalt therapy, at a dose of 70 Gy. There was persistence of the injury. Three sessions were planned, with consecutive fractions of 6.5 Gy in 15 days, with optimization, using a personal mould of autopolymerizable acrylic. The successful possibility to apply the high rate modern brachytherapy was reaffirmed, as a treatment complementary to teletherapy in case of persistence or relapse. A Micro Selectron HDR equipment was used

  4. Development of optimized dosimetric models for HDR brachytherapy

    International Nuclear Information System (INIS)

    Thayalan, K.; Jagadeesan, M.

    2003-01-01

    High dose rate brachytherapy (HDRB) systems are in clinical use for more than four decades particularly in cervical cancer. Optimization is the method to produce dose distribution which assures that doses are not compromised at the treatment sites whilst reducing the risk of overdosing critical organs. Hence HDRB optimization begins with the desired dose distribution and requires the calculations of the relative weighting factors for each dwell position with out changing the source activity. The optimization for Ca. uterine cervix treatment is simply duplication of the dose distribution used for Low dose rate (LDR) applications. In the present work, two optimized dosimetric models were proposed and studied thoroughly, to suit the local clinical conditions. These models are named as HDR-C and HDR-D, where C and D represent configuration and distance respectively. These models duplicate exactly the LDR pear shaped dose distribution, which is a golden standard. The validity of these models is tested in different clinical situations and in actual patients (n=92). These models: HDR-C and HDR-D reduce bladder dose by 11.11% and 10% and rectal dose by 8% and 7% respectively. The treatment time is also reduced by 12-14%. In a busy hospital setup, these models find a place to cater large number of patients, while addressing individual patients geometry. (author)

  5. Coexistence Mechanism for Colocated HDR/LDR WPANs Air Interfaces

    Directory of Open Access Journals (Sweden)

    Prasad Ramjee

    2010-01-01

    Full Text Available This paper addresses the issues of interference management among Low Data Rate (LDR and High Data Rate (HDR WPAN air interfaces that are located in close-proximity (up to 10 cm and eventually on the same multimode device. After showing the noticeable performance degradation in terms of Bit Error Rate (BER and goodput due to the out-of-band interference of an HDR air interface over an LDR air interface, the paper presents a novel coexistence mechanism, named Alternating Wireless Activity (AWA, which is shown to greatly improve the performance in terms of goodput of the most interference vulnerable air interface (i.e., the LDR air interface. The main difference of the proposed mechanism with respect to other collaborative mechanisms based on time-scheduling is that it synchronizes the transmission of the LDR and HDR WPANs at the superframe level instead of packet level. Advantages and limitations of this choice are presented in the paper. Furthermore the functionalities of the AWA mechanism are positioned in a common protocol layer over the Medium Access Control (MAC sublayers of the HDR and LDR devices and it can be used with any standard whose MAC is based on a superframe structure.

  6. Radiobiological considerations in gynaecological HDR and LDR brachytherapy

    International Nuclear Information System (INIS)

    Bauer, M.; Schulz-Wendtland, R.

    1989-01-01

    In brachytherapy the advantages of high dose rate over low dose rate afterloading therapy were obvious. Out-patient treatment becomes possible, the position of the sources is reproducible and can be observed during the treatment and the patients have to be immobilised for only a short time, giving less psychological stress and a decreased risk of thrombosis and embolism. When changing from LDR to HDR afterloading therapy we are not yet able to evaluate its biological impact. Radiobiological considerations and our experimental data, however, give us the following clinical consequences by using HDR brachytherapy: There is a need for about 15 fractions or more and each increase in dose rate requires higher fractioning. Due to the steep dose rate decline and the inhomogeneous dose distribution, multiple equivalence factors are necessary when fractioning is not sufficiently high. Correction factors to reduce the dose close to the source are low, with increasing distance from the source they increase. If HDR radiation therapy is used, the percutaneous dose in the pelvic wall region should be reduced. The reduction of the dose in HDR brachytherapy is a compromise to limit the side effects caused by the radiation. The drawback is a small therapeutic range and reduced therapeutic effectivity at the tumour. (orig.) [de

  7. Die rol van die blanke werker in die motivering van die swart werker

    Directory of Open Access Journals (Sweden)

    G. J. Oosthuizen

    1980-11-01

    Opsomming Die motivering van die Swart werker kan nie in die huidige situasie in isolasie bestudeer word nie, omdat die Blanke werker steeds in die bestuursposisie is en daarom die motivering van die Swart werker kan beïnvloed. Hierdie ondersoek was daarop gerig om die rol van die Blanke werker in die motivering van die Swart werker nader te ondersoek. Die houding en die leierskapsbenadering van die Blanke werker teenoor die Swart werker is gemeet, asook die behoeftes wat volgens die Blanke werker by die Swart werker bestaan, bevredig is, of nie bestaan nie. Die behoeftes van Swart werkers, soos deur hulleself gesien, is ook ondersoek. Ten opsigte van sekere aspekte is beduidende verskille gevind.

  8. Die hervertolking van die paradigma in verband met die ...

    African Journals Online (AJOL)

    Kerkorde van De Mist en die Algemene Reglement van 1816, wat onderskeidelik vir die Kaapse Kerk en die .... Een van die eerstes was Sam Freiherr von Pufendorf (1632-1694) wat in sy werk De habitu religionis ..... Koning was weer aan bewind (vgl Diepenhorst sj:74w; De Visser 1926/1927 lll:202w). 43.1 JD Janssen ...

  9. die heidelbergse kategismus en die kategesemateriaal van die ned

    African Journals Online (AJOL)

    subjek, objek, leerstof en die metodiek van die senior kategese. Bloemfontein: Algemene Jeugkommissie Sondagskoolboekhandel. de rAAd oer ned ger kerken in Zuid AfrikA. 1921. De zevende vergadering: handelinge. 1925. De negende vergadering: handelinge. de villierS, d. W. 1957. Die Kategese in die Ned. Geref.

  10. die sinodale verband van die nederduitse gereformeerde kerk in die

    African Journals Online (AJOL)

    Liezel

    Strauss. Die sinodale verband van die Nederduitse Gereformeerde Kerk. 122 die Vrystaatse Sinode anti-veranderingsgesind of eerder gesond-behoudend of gereformeerd-gematig? Veral as dit .... howe) in moeilike omstandighede gebring is (NG Kerk in die OVS 1865-1912:5). In 'n brief op 8 Augustus 1864 ontken Ds.

  11. Die kerkregtelike posisie van die ouderling en diaken in die ...

    African Journals Online (AJOL)

    ... drie dekades die Kerkreg gevestig as 'n selfstandige vak in die teologiese curriculum, maar ook 'n baie groot rol gespeel daarin dat die beginsels van die kerk like reg beter begryp word. Naas sy wetenskaplike bydrae word met eweveel genoegdoening gedink aan sy bcsondere persoonlikheid, sy werkvermoe, sy humor-.

  12. Riglyne vir die onderwys.

    Directory of Open Access Journals (Sweden)

    J. L. du Plooy

    1960-03-01

    Full Text Available In die afgelope vyftig jaar sedert die Unie tot stand gekom het, is veel op die gebied van onderwys tot stand gebring. Dit is heel natuurlik dat ’n mens sou vra: Wat van die toekoms?

  13. Occurrence Prospect of HDR and Target Site Selection Study in Southeastern of China

    Science.gov (United States)

    Lin, W.; Gan, H.

    2017-12-01

    Hot dry rock (HDR) geothermal resource is one of the most important clean energy in future. Site selection a HDR resource is a fundamental work to explore the HDR resources. This paper compiled all the HDR development projects domestic and abroad, and summarized the location of HDR geothermal geological index. After comparing the geological background of HDR in the southeast coastal area of China, Yangjiang Xinzhou in Guangdong province, Leizhou Peninsula area, Lingshui in Hainan province and Huangshadong in Guangzhou were selected from some key potential target area along the southeast coast of China. Deep geothermal field model of the study area is established based on the comprehensive analysis of the target area of deep geothermal geological background and deep thermal anomalies. This paper also compared the hot dry rock resources target locations, and proposed suggestions for the priority exploration target area and exploration scheme.

  14. Investigation of superstructure damping identification for the HDR containment building

    International Nuclear Information System (INIS)

    Hsieh, B.J.; Kot, C.A.; Srinivasan, M.G.

    1985-01-01

    A method for the estimation of first mode structural damping, developed by other investigators, was applied to shaker test data of the HDR containment building. Due to inadequate precision in the experimental phase measurements no valid results could be obtained. Based on modal analysis it was also noted that for systems such as the HDR building, contributions of higher modes are not negligible as was assumed in the original approach. Therefore, the procedure for the determination of superstructure damping using experimental data was extended to include the effects of higher modes. The extended method does not lead to any higher order nonlinear equations than the first mode approximation and was found to be as simple to apply as the original approach

  15. Die partypolitiek en die toekoms van die Afrikaanse volkskultuur

    Directory of Open Access Journals (Sweden)

    A.P. Treurnicht

    1970-03-01

    Full Text Available Reeds in 1853 het die Zuid Afrikaan hom soos volg uitgelaat: „Dis ’n dwaling wat ons reeds meermale bestry het dat ons as Britse onderdane verplig sou wees, om die Britse nasionaliteit ons s’n te maak. Die Kolonis van Hollandse oorsprong kan geen Engelsman word nie, en moet ook geen Nederlander wil wees nie. Wanneer hy weet om sy standpunt te waardeer, dan sal hy as verligte kolonis die grondtrekke van die Engelse volkskarakter met dié van die Nederlandse harmonies leer verenig en daardeur word wat hy as Kapenaar moet word.”

  16. Intraoperative HDR implant boost for breast cancer (preliminary results)

    International Nuclear Information System (INIS)

    Rodriguez, I.; Torre, M. de la; Gonzalez, E.; Bourel, V.

    1996-01-01

    Introduction: In spite of the fact that it is been discussed whether or not a boost is necessary for all conservative treated breast cancer patients, it is a generalized radiotherapy practice. Since september 1993 we developed a breast conservative protocol for early stage breast cancer (T1-T2) with intraoperative HDR implant boost. Side effects, cosmetic results and recurrence rates are reviewed. Method and Material: From September 1993 we treated 55 patients with intraoperative HDR implant boost to the lumpectomy site for clinical T1 or T2 invasive breast cancer, followed by external megavoltage radiotherapy to the entire breast. We used the Nucletron microselectron HDR remote afterloading system with flexible implant tubes. The geometric distribution of the tubes was performed according to the 'Paris' configuration. Each implant was evaluated by calculating the dose-volume natural histograms. The HDR fractionation schedule consists of three fractions of 4.5Gy each given at least 48 hs apart, and starting between 48-72hs from surgical procedure. The external radiotherapy to the entire breast started one week after the completion of brachytherapy, using conventional fractionation of 5 fractions per week, 1,8Gy per fraction up to 45-50Gy. Results: So far there is not any local recurrence, but medium follow up is only 18 months. We did not observe any acute damage and the cosmetic outcome was 60% excellent, 30% good and 10% acceptable. Two patients developed localized fibrosis, in both the implant involved the submamary fold. Conclusion: The intraoperative implant is the most accurate way to localize the lumpectomy site, to define the target volume, decrease the total treatment time and avoid a second anesthetic procedure without delaying the inpatient time or the initial wound healing process

  17. The use of nomograms in LDR-HDR prostate brachytherapy.

    Science.gov (United States)

    Pujades, Ma Carmen; Camacho, Cristina; Perez-Calatayud, Jose; Richart, José; Gimeno, Jose; Lliso, Françoise; Carmona, Vicente; Ballester, Facundo; Crispín, Vicente; Rodríguez, Silvia; Tormo, Alejandro

    2011-09-01

    The common use of nomograms in Low Dose Rate (LDR) permanent prostate brachytherapy (BT) allows to estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for each clinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adapted to High Dose Rate (HDR). This work sets nomograms for LDR and HDR prostate-BT implants, which are applied to three different institutions that use different implant techniques. Patients treated throughout 2010 till April 2011 were considered for this study. This example was chosen to be the representative of the latest implant techniques and to ensure consistency in the planning. A sufficient number of cases for both BT modalities, prescription dose and different work methodology (depending on the institution) were taken into account. The specific nomograms were built using the correlation between the prostate volume and some characteristic parameters of each BT modality, such as the source Air Kerma Strength, number of implanted seeds in LDR or total radiation time in HDR. For each institution and BT modality, nomograms normalized to the prescribed dose were obtained and fitted to a linear function. The parameters of the adjustment show a good agreement between data and the fitting. It should be noted that for each institution these linear function parameters are different, indicating that each centre should construct its own nomograms. Nomograms for LDR and HDR prostate brachytherapy are simple quality assurance tools, specific for each institution. Nevertheless, their use should be complementary to the necessary independent verification.

  18. The use of nomograms in LDR-HDR prostate brachytherapy

    Directory of Open Access Journals (Sweden)

    Ma Carmen Pujades

    2011-09-01

    Full Text Available Purpose: The common use of nomograms in Low Dose Rate (LDR permanent prostate brachytherapy (BT allowsto estimate the number of seeds required for an implant. Independent dosimetry verification is recommended for eachclinical dosimetry in BT. Also, nomograms can be useful for dose calculation quality assurance and they could be adaptedto High Dose Rate (HDR. This work sets nomograms for LDR and HDR prostate-BT implants, which are applied tothree different institutions that use different implant techniques. Material and methods: Patients treated throughout 2010 till April 2011 were considered for this study. This examplewas chosen to be the representative of the latest implant techniques and to ensure consistency in the planning. A sufficientnumber of cases for both BT modalities, prescription dose and different work methodology (depending on theinstitution were taken into account. The specific nomograms were built using the correlation between the prostatevo lume and some characteristic parameters of each BT modality, such as the source Air Kerma Strength, numberof implanted seeds in LDR or total radiation time in HDR. Results: For each institution and BT modality, nomograms normalized to the prescribed dose were obtained andfitted to a linear function. The parameters of the adjustment show a good agreement between data and the fitting.It should be noted that for each institution these linear function parameters are different, indicating that each centreshould construct its own nomograms. Conclusions: Nomograms for LDR and HDR prostate brachytherapy are simple quality assurance tools, specific foreach institution. Nevertheless, their use should be complementary to the necessary independent verification.

  19. Traceable calibration of hospital 192Ir HDR sources

    International Nuclear Information System (INIS)

    Govinda Rajan, K.N.; Bhatt, B.C.; Pendse, A.M.; Kannan, V.

    2002-01-01

    Presently, no primary standard exists for the standardization of remote afterloading 192 Ir HDR sources. These sources are, therefore, being standardized by a few Secondary Standard Dosimetry Laboratories (SSDLs), in terms of Air Kerma Strength (AKS) or Reference Air Kerma Rate (RAKR) using a 0.6 cc Farmer type chamber, set up as an Interim Standard. These SSDLs offer calibration to well type of ionization chambers that are normally used by the hospitals for calibrating the 192 lr HDR source. Presently, in many countries, including India, well chambers are not commercially available. Nor do these countries offer any calibration service for 192 lr HDR source. With the result users make use of well chambers imported from different countries with their calibration traceable to the country of origin. Since no intercomparisons between these countries have been reported, the measurement consistency between hospitals becomes questionable. The problem is compounded by the fact that these chambers are used for several years without re-calibration since no calibration service is locally available. For instance, in India, the chambers have been in use in hospitals, since 1994, without a second calibration. Not all hospitals use the well chamber for the calibration of the 192 lr HDR source. Many hospitals make use of 0.6 cc chambers, in air, at short source to chamber distances, for measuring the AKS of the source. The latter method is prone to much larger inaccuracy due to the use of very short source to chamber distances without proper calibration jigs, use of 60 Co calibration factor for 192 Ir HDR source calibrations, neglecting correction factors for room scatter, fluence non-uniformity, use of arbitrary buildup factors for the buildup cap of the chamber etc. A comparison of the procedures used at hospitals revealed that various arbitrary methods are in use at hospitals. An indigenously developed well chamber was calibrated against a Reference Standard traceable to the

  20. Rendering of HDR content on LDR displays: an objective approach

    Science.gov (United States)

    Krasula, Lukáš; Narwaria, Manish; Fliegel, Karel; Le Callet, Patrick

    2015-09-01

    Dynamic range compression (or tone mapping) of HDR content is an essential step towards rendering it on traditional LDR displays in a meaningful way. This is however non-trivial and one of the reasons is that tone mapping operators (TMOs) usually need content-specific parameters to achieve the said goal. While subjective TMO parameter adjustment is the most accurate, it may not be easily deployable in many practical applications. Its subjective nature can also influence the comparison of different operators. Thus, there is a need for objective TMO parameter selection to automate the rendering process. To that end, we investigate into a new objective method for TMO parameters optimization. Our method is based on quantification of contrast reversal and naturalness. As an important advantage, it does not require any prior knowledge about the input HDR image and works independently on the used TMO. Experimental results using a variety of HDR images and several popular TMOs demonstrate the value of our method in comparison to default TMO parameter settings.

  1. Vibrational experiments at the HDR [Heissdampfreaktor] German/US cooperation

    International Nuclear Information System (INIS)

    Kot, C.A.; Malcher, L.; Costello, J.F.

    1987-04-01

    As part of an overall effort on the validation of seismic calculational methods, the US NRC/RES is collaborating with the Kernforschungszentrum Karlsruhe, FRG, in the vibrational/earthquake experiments conducted at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG. In the most recent experiments (SHAG), high level excitations were produced in the HDR by means of an eccentric-mass coastdown shaker capable of developing 1000 tons of force. The purpose of the experiments was to investigate full-scale structural response, soil-structure interaction, and piping and equipment response. Data obtained in the tests serve to evaluate analysis methods. In the SHAG experiments, loadings of the HDR soil-structure system approached incipient failure levels as evidenced by high peak accelerations and displacements, local damage, nonlinear behavior, soil subsidence, and wall strains which exceeded estimated limit values. Also, the performance of different pipe hanger configurations for the VKL piping system was compared in these tests under high excitation levels. The support configurations ranged from very rigid systems (strut/snubbers) to very flexible configurations (spring and constant force supports). Pretest and post-test analyses for the building/soil and piping response were performed and are being validated with the test data

  2. WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

    Energy Technology Data Exchange (ETDEWEB)

    Craciunescu, O [Duke University Medical Center, Durham, NC (United States); Todor, D [Virginia Commonwealth University, Richmond, VA (United States); Leeuw, A de

    2014-06-15

    In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy.

  3. WE-F-BRD-01: HDR Brachytherapy II: Integrating Imaging with HDR

    International Nuclear Information System (INIS)

    Craciunescu, O; Todor, D; Leeuw, A de

    2014-01-01

    In recent years, with the advent of high/pulsed dose rate afterloading technology, advanced treatment planning systems, CT/MRI compatible applicators, and advanced imaging platforms, image-guided adaptive brachytherapy treatments (IGABT) have started to play an ever increasing role in modern radiation therapy. The most accurate way to approach IGABT treatment is to provide the infrastructure that combines in a single setting an appropriate imaging device, a treatment planning system, and a treatment unit. The Brachytherapy Suite is not a new concept, yet the modern suites are incorporating state-of-the-art imaging (MRI, CBCT equipped simulators, CT, and /or US) that require correct integration with each other and with the treatment planning and delivery systems. Arguably, an MRI-equipped Brachytherapy Suite is the ideal setup for real-time adaptive brachytherapy treatments. The main impediment to MRI-IGABT adoption is access to MRI scanners. Very few radiation oncology departments currently house MRI scanners, and even fewer in a dedicated Brachytherapy Suite. CBCT equipped simulators are increasingly offered by manufacturers as part of a Brachytherapy Suite installation. If optimized, images acquired can be used for treatment planning, or can be registered with other imaging modalities. This infrastructure is relevant for all forms of brachytherapy, especially those utilizing multi-fractionated courses of treatment such as prostate and cervix. Moreover, for prostate brachytherapy, US imaging systems can be part of the suite to allow for real-time HDR/LDR treatments. Learning Objectives: Understand the adaptive workflow of MR-based IGBT for cervical cancer. Familiarize with commissioning aspects of a CBCT equipped simulator with emphasis on brachytherapy applications Learn about the current status and future developments in US-based prostate brachytherapy

  4. Die Voortrekker-Monument

    Directory of Open Access Journals (Sweden)

    Gerard Moerdyk

    1938-03-01

    Full Text Available Die Eeufeesjaar is vir die Afrikaner ’n tydperk van besieling. Nog nooit sedert die ontstaan van ons volk het een enkele gebeurtenis soveel nasietrots gewek as die honderdjarige herdenking van die Groot Trek. Vir die eerste keer in ons geskiedenis voel ons ons nie meer Kapenaars, Vrystaters, Natalers, en Transvalers nie, maar Afrikaners, saamgesnoer deur die tradisies van ’n selfstandige kultuurvolk. Wanneer die klimaks van die Ossewatrek met die hocksteenlegging van die Voortrekker-Monument bereik word, sal die besieling nie uitsterf nie, die krag wat geskep is sal bly voortgroei tot ’n onweerstaanbare mag. Die Afrikaner sal homself vind, en as die Monument na sowat vyf jaar onthul word, sal die saad wat in hierdie jaar gesaai is, tot voile rypheid gekom het. Dan sal die Monument self tot die volk spreek; intussen egter, is dit wenslik, nee noodsaaklik selfs, om die Monument aan die Afrikaners te verklaar, om ‘n uiteensetting te gee van die noodsaaklikheid van so ’n Monument, sowel as om die motief te verduidelik wat as inspirasie gedien het vir die ontwerpdaar van.

  5. Independent technique of verifying high-dose rate (HDR) brachytherapy treatment plans

    International Nuclear Information System (INIS)

    Saw, Cheng B.; Korb, Leroy J.; Darnell, Brenda; Krishna, K. V.; Ulewicz, Dennis

    1998-01-01

    Purpose: An independent technique for verifying high-dose rate (HDR) brachytherapy treatment plans has been formulated and validated clinically. Methods and Materials: In HDR brachytherapy, dwell times at respective dwell positions are computed, using an optimization algorithm in a HDR treatment-planning system to deliver a specified dose to many target points simultaneously. Because of the variability of dwell times, concerns have been expressed regarding the ability of the algorithm to compute the correct dose. To address this concern, a commercially available low-dose rate (LDR) algorithm was used to compute the doses at defined distances, based on the dwell times obtained from the HDR treatment plans. The percent deviation between doses computed using the HDR and LDR algorithms were reviewed for HDR procedures performed over the last year. Results: In this retrospective study, the difference between computed doses using the HDR and LDR algorithms was found to be within 5% for about 80% of the HDR procedures. All of the reviewed procedures have dose differences of less than 10%. Conclusion: An independent technique for verifying HDR brachytherapy treatment plans has been validated based on clinical data. Provided both systems are available, this technique is universal in its applications and not limited to either a particular implant applicator, implant site, or implant type

  6. Die Britse owerheid en die onderwys op Heidelberg gedurende die ...

    African Journals Online (AJOL)

    The establishment of Christian National Education (CNE) Schools stimulated the concept of mother tongue education. Oor die klaskamerpraktyk en die werklike gehalte van onderrig tydens die kampskooltydperk is daar min bekend. Heidelberg wat na 1902 in 'n belangrike onderwyssentrum in Transvaal ontwikkel het, het ...

  7. Die belangrikste kenmerk van die diereproduksie- bedrywe oor die ...

    African Journals Online (AJOL)

    digdhede teen 1980 uit 'n kudde van 30 rnilj.skape ge- produseer moet word. Tweedens sal die faktore ... die Republiek van Suid-Mrika teen 1980 in totaal 28 milj. sal wees. Indien die produsente dit as 'n ..... Appendix Table 4 in Digestive Physiology and nutrition of ruminants Vol. 3 Ed. and Publ. D.C. Church, Oregon State ...

  8. DIE ROL VAN DIE TAALWETENSKAP IN DIE ONTWIKKELING VAN ...

    African Journals Online (AJOL)

    aanslag op die sogenaamde "Intentional Fallacy", heelwat verder. n. Mens sou hier eintlik ook op die invloed van Lacan se toepassing van. De Sacs sure op Freud moet wys, en op Macherey se Theory of Literary. Production. Barthes is naamlik besig om repressie teen te werk, en die teks as produksieproses in stede van ...

  9. Simultaneous radiochemotherapy and endoluminal HDR brachytherapy in esophageal cancer; Simultane Radiochemotherapie mit intraluminaler HDR-Brachytherapie des Oesophaguskarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Patonay, P.; Naszaly, A.; Mayer, A. [Hauptstaedtisches Zentrum fuer Radioonkologie und Strahlentherapie, Budapest (Hungary)

    2007-02-15

    Purpose: to study efficacy and toxicity of radiochemotherapy in esophageal cancer including initial endoluminal high-dose-rate brachytherapy (HDR-BT). Patients and methods: between 01/1995 and 06/2005, 61 patients with esophageal cancer were treated preoperatively with definitive and palliative intent. Treatment started with intraluminal HDR-BT for recanalization of the esophagus (single fraction size of 8 Gy in 0.5 cm depth, three times, q7d) followed by external-beam radiation therapy (50 Gy total dose, 5 x 2 Gy/week, 25 fractions in 5 weeks). Chemotherapy was started simultaneously with external irradiation (three courses of cisplatin and 5-fluorouracil, q21d). Results: swallowing function improved in 55/61 patients (dysphagia classification according to the RTOG), and worsened in 6/61 patients, respectively. Median duration of symptomatic improvement was 11 months, median follow-up 12 months (range 3-68 months). Following simultaneous radiochemotherapy, tumor resectability was achieved in 7/25 patients of the neoadjuvant group, and the histological specimen showed complete remission in 6/7 patients. Conclusion: these results indicate a favorable effect of simultaneous radiochemotherapy starting with endoluminal HDR-after-loading-(AL-)BT in esophageal cancer. (orig.)

  10. SU-E-T-124: Dosimetric Comparison of HDR Brachytherapy and Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J [Purdue University, West Lafayette, IN (United States); Wu, H [IUPUI, Indianapolis, IN (United States); Das, I [Indiana University- School of Medicine, Indianapolis, IN (United States)

    2014-06-01

    Purpose: Brachytherapy is known to be able to deliver more radiation dose to tumor while minimizing radiation dose to surrounding normal tissues. Proton therapy also provides superior dose distribution due to Bragg peak. Since both HDR and Intensity Modulated Proton Therapy (IMPT) are beneficial for their quick dose drop off, our goal in this study is to compare the pace of dose gradient drop-off between HDR and IMPT plans based on the same CT image data-set. In addition, normal tissues sparing were also compared among HDR, IMPT and SBRT. Methods: Five cervical cancer cases treated with EBRT + HDR boost combination with Tandem and Ovoid applicator were used for comparison purpose. Original HDR plans with prescribed dose of 5.5 Gy x 5 fractions were generated and optimized. The 100% isodose line of HDR plans was converted to a dose volume, and treated as CTV for IMPT and SBRT planning. The same HDR CT scans were also used for IMPT plan and SBRT plan for direct comparison. The philosophy of the IMPT and SBRT planning was to create the same CTV coverage as HDR plans. All three modalities treatment plans were compared to each other with a set of predetermined criteria. Results: With similar target volume coverage in cervix cancer boost treatment, HDR provides a slightly sharper dose drop-off from 100% to 50% isodose line, averagely in all directions compared to IMPT. However, IMPT demonstrated more dose gradient drop-off at the junction of the target and normal tissues by providing more normal tissue sparing and superior capability to reduce integral dose. Conclusion: IMPT is capable of providing comparable dose drop-off as HDR. IMPT can be explored as replacement for HDR brachytherapy in various applications.

  11. Wêreldmededingendheid en die tegnologie

    Directory of Open Access Journals (Sweden)

    C. W. I. Pistorius

    1996-07-01

    Full Text Available Afgesien van die interne uitdagings wat die Heropbou- en Ontwikkelingsprogram (HOP aan Suid-Afrika bied, moet die land ook tred hou met die veranderende globale omgewing, spesifiek die toenemende belangrikheid van ekonomiese sekuriteit as komponent van nasionale sekuriteit. Die konsep van mededingendheid vergestalt die doelwit wat nagestreef moet word ten einde die ontluikende globale ekonomiese stryd aan te durf. As ’n belangrike drywer van ekonomiese welvaart is tegnologie een van die belangrikste sleutels tot internasionale mededingendheid. Tegnologiese innovasie is die proses wat as hefboom hiervoor gebruik moet word. Dit is egter nodig dat tegnologie, en spesifiek die proses van tegnologiese innovasie, formeel en gestruktureerd bestuur moet word, sowel op nasionale as firmavlak. Op nasionale vlak is die voorsiene Nasionale Innovasiestelsel beslis ’n stap in die regte rigting.

  12. die ontstaan en die ontwikkeling van die skoolkadette-stelsel in die rsa

    African Journals Online (AJOL)

    toe algemene diensplig ingestel is. Die diens- plig het intussen sy volle beslag gekry en in. Weermagkringe het die gedagte posgevat dat skoolkadette. 'n deeglike ondersoek vereis ten einde die skoolgaande seun vir sy komende nasionale diensplig te orienteer. Tydens kadetopleldlng leer die seuns al die fynere kunsles ...

  13. Van die Gasredakteur

    African Journals Online (AJOL)

    cherish and teach.'1. Die Fakulteit Geneeskunde van die Universiteit van die Oranje-Vrystaat het pragtig gegroei ge- durende die eerste 21 jaar van sy bestaan. Die entoesiasme, doelgerigtheid, harde werk en inisia- tiewe van 'n groot aantal persone was hiervoor verantwoordelik. 'If we see a bit more clearly than they, it is ...

  14. Halfkrone vir die Nagmaal

    African Journals Online (AJOL)

    Owner

    die omgewing van Velddrif en Laaiplek, ook noordwaarts verby Lambertsbaai tot by. Doringbaai en Strandfontein. “Haar seeverhale is Sussie (Kotze) se belangrikste bydrae tot die Afrikaanse letterkunde”, sê Kotzé-Myburgh in die voorwoord van die versamelbundel. Die leser word herinner aan Kotze se debuutroman, ...

  15. Die teologie in gesprek met die ekonomie

    African Journals Online (AJOL)

    (1723-1790) sy vertrekpunt neem, ontwikkel, as oorwinnaars uit die Franse Revolu .... Die onmiddellike sukses van Adam Smith se 'Wealth of Nations' was .... alle vorme van sosialisme niks anders as 'kommunisme' (Wassenaar 1977:12) nie.

  16. Exploration of joint systems and major horizontal stress direction in HDR drillholes of the Soultz site (Alsace, France)

    Energy Technology Data Exchange (ETDEWEB)

    Genter, A [BRGM/GIG, Orleans (France); Tenzer, H [Stadtwerke Bad Urach (Germany)

    1997-12-01

    Borehole imaging logs enable continuous recording of natural and artificial planar discontinuities on the drillhole wall and data of the drillhole geometry to be made. Efforts were made to resolve the orientation and characterization of the natural joint system, the active fault pattern, the alteration zones, the orientation of microcracks and the direction of maximum horizontal stress. Intense logging operations and measurements were carried out in the HDR drillholes GPK1 and EPS1 between 1000 and 3600 m depth in the Muschelkalk, Bunter and Granite at Soultz sous Forets. With the help of investigations on subvertical fractures the orientation of the maximum horizontal stress direction was determined as N175 E{+-}17 . These results are consistent with previous investigations performed in the horeholes GPK-1 and EPS-1. (orig./AKF) [Deutsch] Bohrlochmessungen mit dem akustschen Borehole Televiewer und elektrischen Formation MicroScanner (Imager) sowie dem Azimuthal Resistivity Imager und verschiedenen Sonic-Sonden ermoeglichen eine kontinuierliche Aufnahme sowohl von natuerlichen und kuenstlich erzeugten planaren Diskontinuitaeten an der Bohrlochwand als auch der Bohrlochgeometrie. Es wurden die Orientierung und Charakterisierung des natuerlichen Kluftsystems, das aktive Stoerungsmuster, die Alterationszonen, die Orientierung von Mikrorissen und die Orientierung der maximalen horizontalen Hauptspannungsrichtung ermittelt. Die Verfuegbarkeit von Strukturdaten aus Bohrloechern durch Bohrlochmessungen und hydraulischen Testen ermoeglicht die Bestimmung von hydraulisch aktiven Klueften und deren Beziehung zum regionalen Spannungsfeld. Mit Hilfe spezieller Bohrloch-Logs wurden die Orientierung und Haeufigkeit planarer Diskontinuitaeten und ihre scheinbare Oeffnungsweite sowie die Vorzugsrichtung der verschiedenen scheinbaren Weiten bestimmt. Innerhalb des gemeinsamen europaeischen Hot-Dry-Rock-Geothermal-Forschungsprogramms wurden vielfaeltige Bohrlochmessungen in den

  17. MO-B-BRC-00: Prostate HDR Treatment Planning - Considering Different Imaging Modalities

    International Nuclear Information System (INIS)

    2016-01-01

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions

  18. MO-B-BRC-00: Prostate HDR Treatment Planning - Considering Different Imaging Modalities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    Brachytherapy has proven to be an effective treatment option for prostate cancer. Initially, prostate brachytherapy was delivered through permanently implanted low dose rate (LDR) radioactive sources; however, high dose rate (HDR) temporary brachytherapy for prostate cancer is gaining popularity. Needle insertion during prostate brachytherapy is most commonly performed under ultrasound (U/S) guidance; however, treatment planning may be performed utilizing several imaging modalities either in an intra- or post-operative setting. During intra-operative prostate HDR, the needles are imaged during implantation, and planning may be performed in real time. At present, the most common imaging modality utilized for intra-operative prostate HDR is U/S. Alternatively, in the post-operative setting, following needle implantation, patients may be simulated with computed tomography (CT) or magnetic resonance imaging (MRI). Each imaging modality and workflow provides its share of benefits and limitations. Prostate HDR has been adopted in a number of cancer centers across the nation. In this educational session, we will explore the role of U/S, CT, and MRI in HDR prostate brachytherapy. Example workflows and operational details will be shared, and we will discuss how to establish a prostate HDR program in a clinical setting. Learning Objectives: Review prostate HDR techniques based on the imaging modality Discuss the challenges and pitfalls introduced by the three imagebased options for prostate HDR brachytherapy Review the QA process and learn about the development of clinical workflows for these imaging options at different institutions.

  19. Characteristics of hearing loss in HDR (hypoparathyroidism, sensorineural deafness, renal dysplasia) syndrome

    NARCIS (Netherlands)

    van Looij, Marjolein A. J.; Meijers-Heijboer, Hanne; Beetz, Rolf; Thakker, Rajesh V.; Christie, Paul T.; Feenstra, Lou W.; van Zanten, Bert G. A.

    2006-01-01

    Haploinsufficiency of the zinc finger transcription factor GATA3 causes the triad of hypoparathyroidism, deafness and renal dysplasia, known by its acronym HDR syndrome. The purpose of the current study was to describe in detail the auditory phenotype in human HDR patients and compare these to

  20. TU-C-201-01: Clinical Implementation of HDR: A New User’s Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hallaq, H. [The University of Chicago (United States)

    2015-06-15

    Recent use of HDR has increased while planning has become more complex often necessitating 3D image-based planning. While many guidelines for the use of HDR exist, they have not kept pace with the increased complexity of 3D image-based planning. Furthermore, no comprehensive document exists to describe the wide variety of current HDR clinical indications. This educational session aims to summarize existing national and international guidelines for the safe implementation of an HDR program. A summary of HDR afterloaders available on the market and their existing applicators will be provided, with guidance on how to select the best fit for each institution’s needs. Finally, the use of checklists will be discussed as a means to implement a safe and efficient HDR program and as a method by which to verify the quality of an existing HDR program. This session will provide the perspective of expert HDR physicists as well as the perspective of a new HDR user. Learning Objectives: Summarize national and international safety and staffing guidelines for HDR implementation Discuss the process of afterloader and applicator selection for gynecologic, prostate, breast, interstitial, surface treatments Learn about the use of an audit checklist tool to measure of quality control of a new or existing HDR program Describe the evolving use of checklists within an HDR program.

  1. Die dogmatiese binding van die prediking

    African Journals Online (AJOL)

    genoemde probleemstelling wat ons homileties na riglyne wil soek, sonder die pretensie dat finale oplossings gevind sal word. Om hierdie probleem te ontleed is dit nodig om eers kortliks 'n begripsbepaling van die begrippe dogma, binding en prediking te maak. Vanuit die begripsbepaling kan ons dan probeer vasstel wat ...

  2. DIE PERSOON VAN VREDE IN DIE SENDING

    African Journals Online (AJOL)

    aan dat 'n lewe onder die gesag van God tot volle vrede lei: “In coming under the rule of Yahweh, moreover, life was made whole and safe.” Dit is spesifiek in die tempel waar die volheid van God se vrede ondervind word (1997:662):. The temple is indeed the place where Israel entered into Yahweh's full zone of shalom.

  3. : Light Steering Projection Systems and Attributes for HDR Displays

    KAUST Repository

    Damberg, Gerwin

    2017-06-02

    New light steering projectors in cinema form images by moving light away from dark regions into bright areas of an image. In these systems, the peak luminance of small features can far exceed full screen white luminance. In traditional projectors where light is filtered or blocked in order to give shades of gray (or colors), the peak luminance is fixed. The luminance of chromatic features benefit in the same way as white features, and chromatic image details can be reproduced at high brightness leading to a much wider overall color gamut coverage than previously possible. Projectors of this capability are desired by the creative community to aid in and enhance storytelling. Furthermore, reduced light source power requirements of light steering projectors provide additional economic and environmental benefits. While the dependency of peak luminance level on (bright) image feature size is new in the digital cinema space, display technologies with identical characteristics such as OLED, LED LCD and Plasma TVs are well established in the home. Similarly, direct view LED walls are popular in events, advertising and architectural markets. To enable consistent color reproduction across devices in today’s content production pipelines, models that describe modern projectors and display attributes need to evolve together with HDR standards and available metadata. This paper is a first step towards rethinking legacy display descriptors such as contrast, peak luminance and color primaries in light of new display technology. We first summarize recent progress in the field of light steering projectors in cinema and then, based on new projector and existing display characteristics propose the inclusion of two simple display attributes: Maximum Average Luminance and Peak (Color) Primary Luminance. We show that the proposed attributes allow a better prediction of content reproducibility on HDR displays. To validate this assertion, we test professional content on a commercial HDR

  4. Realistic camera noise modeling with application to improved HDR synthesis

    Science.gov (United States)

    Goossens, Bart; Luong, Hiêp; Aelterman, Jan; Pižurica, Aleksandra; Philips, Wilfried

    2012-12-01

    Due to the ongoing miniaturization of digital camera sensors and the steady increase of the "number of megapixels", individual sensor elements of the camera become more sensitive to noise, even deteriorating the final image quality. To go around this problem, sophisticated processing algorithms in the devices, can help to maximally exploit the knowledge on the sensor characteristics (e.g., in terms of noise), and offer a better image reconstruction. Although a lot of research focuses on rather simplistic noise models, such as stationary additive white Gaussian noise, only limited attention has gone to more realistic digital camera noise models. In this article, we first present a digital camera noise model that takes several processing steps in the camera into account, such as sensor signal amplification, clipping, post-processing,.. We then apply this noise model to the reconstruction problem of high dynamic range (HDR) images from a small set of low dynamic range (LDR) exposures of a static scene. In literature, HDR reconstruction is mostly performed by computing a weighted average, in which the weights are directly related to the observer pixel intensities of the LDR image. In this work, we derive a Bayesian probabilistic formulation of a weighting function that is near-optimal in the MSE sense (or SNR sense) of the reconstructed HDR image, by assuming exponentially distributed irradiance values. We define the weighting function as the probability that the observed pixel intensity is approximately unbiased. The weighting function can be directly computed based on the noise model parameters, which gives rise to different symmetric and asymmetric shapes when electronic noise or photon noise is dominant. We also explain how to deal with the case that some of the noise model parameters are unknown and explain how the camera response function can be estimated using the presented noise model. Finally, experimental results are provided to support our findings.

  5. HDR brachytherapy for superficial non-melanoma skin cancers

    International Nuclear Information System (INIS)

    Gauden, Ruth; Pracy, Martin; Avery, Anne-Marie; Hodgetts, Ian; Gauden, Stan

    2013-01-01

    Our initial experience using recommended high dose per fraction skin brachytherapy (BT) treatment schedules, resulted in poor cosmesis. This study aimed to assess in a prospective group of patients the use of Leipzig surface applicators for High Dose Rate (HDR) brachytherapy, for the treatment of small non-melanoma skin cancers (NMSC) using a protracted treatment schedule. Treatment was delivered by HDR brachytherapy with Leipzig applicators. 36Gy, prescribed to between 3 to 4mm, was given in daily 3Gy fractions. Acute skin toxicity was evaluated weekly during irradiation using the Radiation Therapy Oncology Group criteria. Local response, late skin effects and cosmetic results were monitored at periodic intervals after treatment completion. From March 2002, 200 patients with 236 lesions were treated. Median follow-up was 66 months (range 25–121 months). A total of 162 lesions were macroscopic, while in 74 cases, BT was given after resection because of positive microscopic margins. There were 121 lesions that were basal cell carcinomas, and 115 were squamous cell carcinomas. Lesions were located on the head and neck (198), the extremities (26) and trunk (12). Local control was 232/236 (98%). Four patients required further surgery to treat recurrence. Grade 1 acute skin toxicity was detected in 168 treated lesions (71%) and grade 2 in 81 (34%). Cosmesis was good or excellent in 208 cases (88%). Late skin hypopigmentation changes were observed in 13 cases (5.5%). Delivering 36Gy over 2 weeks to superficial NMSC using HDR brachytherapy is well tolerated and provides a high local control rate without significant toxicity.

  6. n Oorsig van die huidige stand van navorsing oor die

    African Journals Online (AJOL)

    Test

    7 Jun 2011 ... Die eerste maal wat dit as deel van die teks van 1 Johannes aangehaal word, is in die. 4de eeu in 'n Latynse teks, Liber Apologeticus (hf 4). Eers aan die einde van die 16de eeu is dit in 'n amptelike Katolieke uitgawe van die Vulgaat ingesluit. Die doel van die Johannesbriewe. Waarom is die Briewe ...

  7. Die Ware Buch und die Philologie

    Directory of Open Access Journals (Sweden)

    Bernhard Hurch

    2017-10-01

    Full Text Available Die im 19. Jahrhundert sich verändernden Produktionsbedingungen für Druckwerke (Buchdruck, Satz, Papier, Bindung wirkten katalysierend auf die Fachkonstitution und Institutionalisierung der Philologien. Hier steht der tatsächliche Buchmarkt im Vordergrund der Darstellung, das Käuferpublikum und die Voraussetzungen des Vertriebs. Dazu gehören auch die Rezension als entstehende Textsorte und die rasch arbeitenden Rezensionsorgane. F.-R. Hausmann wurde in den letzten Jahren unentbehrlicher Mitarbeiter dieses im Rahmen des Grazer Schuchardt-Projekts "Netzwerk des Wissens" angesiedelten Ansatzes.

  8. Cost modelling of electricity-producing hot dry rock (HDR) geothermal systems in the United Kingdom

    International Nuclear Information System (INIS)

    Doherty, P.; Harrison, R.

    1995-01-01

    A detailed and comprehensive cost model for Hot Dry Rock (HDR) electricity producing systems has been developed in this study. The model takes account of the major aspects of the HDR system, parameterized in terms of the main physical and cost parameters of the resource and the utilization system. A doublet configuration is assumed, and the conceptual HDR system which is defined in the study is based upon the UK Department of Energy (DEn) HDR geothermal R and D programme. The model has been used to calculate the costs of HDR electricity for a UK defined base case which represents a consensus view of what might be achieved in Cornwall in the long term. At 14.2 p/kWh (1988 costs) this cost appears to be unacceptably high. A wide-ranging sensitivity study has also been carried out on the main resource, geometrical, and operational parameters of the HDR system centred around the UK base case. The sensitivity study shows the most important parameters to be thermal gradient and depth. The geometrical arrangement and the shape of the reservoir constitute major uncertainties in HDR systems. Their effect on temperature has a major influence on system performance, and therefore a range of theoretically possible geometries have been studied and the importance of geometrical effects on HDR electricity costs assessed. The most cost effective HDR arrangement in terms of optimized volumes and flow rates has been investigated for a world-wide range of thermal settings. The main conclusions from this study suggests that for HDR electricity to be economic, thermal gradients of 55 o C/km and above, well depths of 5 km or less, and production fluid temperatures of 210 o C and above are required. (UK)

  9. Mathematical simulation of biologically equivalent doses for LDR-HDR

    International Nuclear Information System (INIS)

    Slosarek, K.; Zajusz, A.

    1996-01-01

    Based on the LQ model examples of biologically equivalent doses LDR, HDR and external beams were calculated. The biologically equivalent doses for LDR were calculated by appending to the LQ model the corrector for the time of repair of radiation sublethal damages. For radiation continuously delivered at a low dose rate the influence of sublethal damage repair time changes on biologically equivalent doses were analysed. For fractionated treatment with high dose rate the biologically equivalent doses were calculated by adding to the LQ model the formula of accelerated repopulation. For total biologically equivalent dose calculation for combine LDR-HDR-Tele irradiation examples are presented with the use of different parameters of the time of repair of sublethal damages and accelerated repopulation. The calculations performed show, that the same biologically equivalent doses can be obtained for different parameters of cell kinetics changes during radiation treatment. It also shows, that during biologically equivalent dose calculations for different radiotherapy schedules, ignorance of cell kinetics parameters can lead to relevant errors

  10. HDR IMAGING FOR FEATURE DETECTION ON DETAILED ARCHITECTURAL SCENES

    Directory of Open Access Journals (Sweden)

    G. Kontogianni

    2015-02-01

    Full Text Available 3D reconstruction relies on accurate detection, extraction, description and matching of image features. This is even truer for complex architectural scenes that pose needs for 3D models of high quality, without any loss of detail in geometry or color. Illumination conditions influence the radiometric quality of images, as standard sensors cannot depict properly a wide range of intensities in the same scene. Indeed, overexposed or underexposed pixels cause irreplaceable information loss and degrade digital representation. Images taken under extreme lighting environments may be thus prohibitive for feature detection/extraction and consequently for matching and 3D reconstruction. High Dynamic Range (HDR images could be helpful for these operators because they broaden the limits of illumination range that Standard or Low Dynamic Range (SDR/LDR images can capture and increase in this way the amount of details contained in the image. Experimental results of this study prove this assumption as they examine state of the art feature detectors applied both on standard dynamic range and HDR images.

  11. Fast exposure time decision in multi-exposure HDR imaging

    Science.gov (United States)

    Piao, Yongjie; Jin, Guang

    2012-10-01

    Currently available imaging and display system exists the problem of insufficient dynamic range, and the system cannot restore all the information for an high dynamic range (HDR) scene. The number of low dynamic range(LDR) image samples and fastness of exposure time decision impacts the real-time performance of the system dramatically. In order to realize a real-time HDR video acquisition system, this paper proposed a fast and robust method for exposure time selection in under and over exposure area which is based on system response function. The method utilized the monotony of the imaging system. According to this characteristic the exposure time is adjusted to an initial value to make the median value of the image equals to the middle value of the system output range; then adjust the exposure time to make the pixel value on two sides of histogram be the middle value of the system output range. Thus three low dynamic range images are acquired. Experiments show that the proposed method for adjusting the initial exposure time can converge in two iterations which is more fast and stable than average gray control method. As to the exposure time adjusting in under and over exposed area, the proposed method can use the dynamic range of the system more efficiently than fixed exposure time method.

  12. Fricke gel-layer dosimetry in HDR brachytherapy

    International Nuclear Information System (INIS)

    Gambarini, G.; Negri, A.; Carrara, M.; Marchesini, R.

    2008-01-01

    Full text: In the last decade, technological improvements in radiotherapy have been significant and consequently the use and importance of radiotherapy in cancer treatment have increased greatly. In brachytherapy, new possibilities have been opened by the impressive progresses in 3D imaging, by the development of sophisticated techniques for modern afterloaders and by the constantly increasing speed and capacity of computers. However, these methodological improvements require corresponding improvements in the dosimetry methods, in order to ensure that the values calculated with computer treatment planning systems, adopted in the clinical praxis, agree with the delivered dose distributions. Fricke gel-layer dosimeters (FGLD) are under study by our group as a reliable alternative to films, semiconductors arrays or thermoluminescent dosimeters (TLDs). In the last years, we have significantly improved this technique by defining the FGLD best chemical composition, by optimizing the image acquisition assessment and by developing a dedicated software for image analysis. In this study, experimental measurements of planar dose distributions of a clinical 192 Ir source (Microselectron HDR, Nucletron) obtained by irradiating a series of piled-up FGL dosimeters in a tissue-equivalent phantom are presented. The obtained results were in accordance to TLD measurements and to treatment planning system (Plato, Nucletron) calculations. FGLD have proven to be a reliable tool to achieve HDR brachytherapy dose distribution measurements

  13. High Brightness HDR Projection Using Dynamic Freeform Lensing

    KAUST Repository

    Damberg, Gerwin

    2016-05-03

    Cinema projectors need to compete with home theater displays in terms of image quality. High frame rate and spatial resolution as well as stereoscopic 3D are common features today, but even the most advanced cinema projectors lack in-scene contrast and, more important, high peak luminance, both of which are essential perceptual attributes of images appearing realistic. At the same time, HDR image statistics suggest that the average image intensity in a controlled ambient viewing environment such as the cinema can be as low as 1% for cinematic HDR content and not often higher than 18%, middle gray in photography. Traditional projection systems form images and colors by blocking the source light from a lamp, therefore attenuating between 99% and 82% of light, on average. This inefficient use of light poses significant challenges for achieving higher peak brightness levels. In this work, we propose a new projector architecture built around commercially available components, in which light can be steered to form images. The gain in system efficiency significantly reduces the total cost of ownership of a projector (fewer components and lower operating cost), and at the same time increases peak luminance and improves black level beyond what is practically achievable with incumbent projector technologies. At the heart of this computational display technology is a new projector hardware design using phase modulation in combination with a new optimization algorithm that is capable of on-the-fly computation of freeform lens surfaces. © 2016 ACM.

  14. Seismic investigations of the HDR Safety Program. Summary report

    International Nuclear Information System (INIS)

    Malcher, L.; Schrammel, D.; Steinhilber, H.; Kot, C.A.

    1994-08-01

    The primary objective of the seismic investigations, performed at the HDR facility in Kahl/Main, FRG was to validate calculational methods for the seismic evaluation of nuclear-reactor systems, using experimental data from an actual nuclear plant. Using eccentric mass shaker excitation the HDR soil/structure system was tested to incipient failure, exhibiting highly nonlinear response and demonstrating that structures not seismically designed can sustain loads equivalent to a design basin earthquake (DBE). Load transmission from the structure to piping/equipment indicated significant response amplifications and shifts to higher frequencies, while the response of tanks/vessels depended mainly on their support conditions. The evaluation of various piping support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is important to limiting pipe greens. Piping at loads exceeding the DBE eightfold still had significant margins and failure is improbable inspite of multiple support failures. The mean value for pipe damping, even under extreme loads, was found to be about 4%. Comparison of linear and nonlinear computational results with piping response measurements showed that predictions have a wide scatter and do not necessarily yield conservative responses underpredicting, in particular, peak support forces. For the soil/structure system the quality of the predictions did not depend so much on the complexity of the modeling, but rather on whether the model captured the salient features and nonlinearities of the system

  15. Prostate HDR brachytherapy catheter displacement between planning and treatment delivery

    International Nuclear Information System (INIS)

    Whitaker, May; Hruby, George; Lovett, Aimee; Patanjali, Nitya

    2011-01-01

    Background and purpose: HDR brachytherapy is used as a conformal boost for treating prostate cancer. Given the large doses delivered, it is critical that the volume treated matches that planned. Our outpatient protocol comprises two 9 Gy fractions, two weeks apart. We prospectively assessed catheter displacement between CT planning and treatment delivery. Materials and methods: Three fiducial markers and the catheters were implanted under transrectal ultrasound guidance. Metal marker wires were inserted into 4 reference catheters before CT; marker positions relative to each other and to the marker wires were measured from the CT scout. Measurements were repeated immediately prior to treatment delivery using pelvic X-ray with marker wires in the same reference catheters. Measurements from CT scout and film were compared. For displacements of 5 mm or more, indexer positions were adjusted prior to treatment delivery. Results: Results are based on 48 implants, in 25 patients. Median time from planning CT to treatment delivery was 254 min (range 81–367 min). Median catheter displacement was 7.5 mm (range −2.9–23.9 mm), 67% of implants had displacement of 5 mm or greater. Displacements were predominantly caudal. Conclusions: Catheter displacement can occur in the 1–3 h between the planning CT scan and treatment. It is recommended that departments performing HDR prostate brachytherapy verify catheter positions immediately prior to treatment delivery.

  16. Die vrede van Münster / Westfale en die betekenis daarvan vir die ...

    African Journals Online (AJOL)

    In die Suid-Afrikaanse kerkgeskiedenis egter is die Vrede van Münster as epogmakende gebeure tot dusver nie net in die algemeen verwaarloos nie, maar boonop is die direkte verband tussen hierdie sentrale historiese baken aan die een kant en aan die ander kant die vestiging van die VOC se verversingspos aan die ...

  17. Tegnologie en die mens

    African Journals Online (AJOL)

    omgewingsbesoedeling, volgend op industrialisasie en verstedeliking, gee uit- ing tot krete van wanhoop en frustrasie. Die maatskaplike ontwrigting agv outomatisasie het die begrippe van vervreemding en naam- loosheid op die voorgrond van sosiale be- wustheid geplaas. • Die Neutrale Siening. Tegnologie was nag. 34.

  18. GODSBEELDE IN DIE LITURGIE

    African Journals Online (AJOL)

    15 Mei 2010 ... Biezeveld, de Boer, Brümmer, Muis. 2001; Brown 2006; Durand 2007). ... Wanneer sal hy weer in God se teenwoordigheid verskyn (vers 3)? Dié vraag is vol onsekerheid. (Schuman 2004:8). Sy onsekerheid ... God se volk en die enkeling in die geskiedenis het al die trou van God ervaar waarop die digter ...

  19. Die ontwikkeling van die bestuursmotiveringsvraelys (BMV

    Directory of Open Access Journals (Sweden)

    A. S. Engelbrecht

    1991-06-01

    Full Text Available The development of the Managerial Motivation Questionnaire (MMQ: Several criticisms of the psychometric suitability of existing measures of managerial motivation are reported in the literature. This study aimed at developing a new psychometrically sound instrument, the Managerial Motivation Questionnaire (MMQ. This was done on the basis of a comprehensive study of the literature on managerial motivation and the role-motivation theory. The preliminary MMQ was systematically shortened and refined until the final MMQ of 98 items was composed. This was based on social desirability and semantic appraisal, item analysis and factor analysis of the questionnaire. The results indicate that it was possible to develop a final MMQ that was relatively free of social desirability. It further demonstrated satsifactory internal consistencies on two samples (a = 0/90, N = 360; a = 0/91, N = 535, where all subscale items were found to be relatively pure measures of the isolated factors. Although some evidence was found providing support for the reliability of the MMQ, a need for further research on the construct validity of managerial motivation still exists. Opsomming In die literatuur word verskeie punte van kritiek teen die psigometriese geskiktheid van bestaande meetinstrumente van bestuursmotivering gerapporteer. Die doelstelling van hierdie studie was dus om aan die hand van die konseptuele omiyning van bestuursmotivering, en die rolmotiveringsteorie as algemene verwysingsraamwerk, 'n nuwe psigometries aanvaarbare meetinstrument, die Bestuursmotiveringsvraelys (BMV, te ontwikkel. Op grond van sosiale wenslikheids- en semantiese beoordeling, itemontleding en faktorontleding van die voorlopige BMV is die vraelys stelselmatig verkort en verfyn totdat die finale BMV van 98 items saamgestel is. Die resultate dui daarop dat hierdie studie wel daarin geslaag het om 'n finale BMV te ontwikkel wat relatief vry van sosiale wenslikheid is, bevredigende interne

  20. Varswateralge en die ekonomie

    Directory of Open Access Journals (Sweden)

    W. E. Scott

    1988-03-01

    Full Text Available Die artikel bespreek die ekonomiese belong wat varswateralge alreeds het en hul moontlike verdere ontginning in die toekoms. Sowel gewenste as ongewenste aspekte word oorweeg en hoofsaaklik met voorbeelde uit Suid-Afrika geïllustreer. Die oormatige ontwikkeling van ongewenste alge in varswater verlaag die watergehalte dear verskeie chemiese veranderinge, wat kan wissel van smake en geure tot die produksie van verbindings wat gesondheidsgevare vir mens of dier inhou. Verwydering van ongewenste alge dra aansienlik by tot die koste van waterbehandeling. Oormatige alggroei belemmer ontspanningsgebruike en kan eiendomswaardes langs rivier- en damoewers beïnvloed.

  1. Prediking aan die hand van die metafoor van fiksieskryf

    African Journals Online (AJOL)

    p1243322

    HTS 64(3) 2008 siening van die self en waarheid. In die pre-moderne paradigma kan die dominante metafoor verstaan word aan die hand van 'n spieël wat die lig uit 'n transendente oorsprong weerkaats, terwyl die moderne paradigma uitgedruk word met die metafoor van 'n lamp wat 'n eie, oorspronklike lig binne die self.

  2. e .Kuraioriufn. DIE W ETENSKAPLIKE BETEKENIS VAN DIE W ERK

    African Journals Online (AJOL)

    Test

    ENGELBRECHT ver antwoordelik vir die Ou-Testamentiese vakke en Hebreeus. Die aan stelling van 'n derde professor het noodsaaklik geword, want dit sou. 85 .... De .Spreuken ran 5a/o?no omvat die nuwe vertaling en die ekse gese van die eerste 24 hoofstukke van die Spreukeboek. Die geskoold- heid in die Semitiese ...

  3. Die dialogiese prinsipe

    Directory of Open Access Journals (Sweden)

    J. J. de Klerk

    1981-08-01

    Full Text Available Met die dialogiese prinsipe word daardie beginsel bedoel, waarin die tweerigtingverkeer of kommunikasie onder, of met, of deur die mense op 'n heel besondere gesprekmatige wyse gere�l word. Tot die wese van die dialogiese prinsipe behoort "als Grundvoraussetzung das Ernstnehmen des Gesprachspartners und das darin enthaltene zuhoren-konnen. Dialog ist also etwas anderes als Disput oder Diskussion. Er setzt gegenseitiges Vertrauen und Hochachtung voraus."

  4. Die sestienpersoonlikheidsfaktorvraelys as hulpmiddel by die takseersentrum

    Directory of Open Access Journals (Sweden)

    J. C. D. Augustyn

    1988-05-01

    Full Text Available The 16PF Personality Test as an aid to the assessment centre Assessment centres still remains costly and thime consuming. This study investigates the reduction of time and costs by the use of the 16 PF Personality Test as a method for measuring management dimensions. Promising results were obtained with a relatively small sample for the prediction of initiative and perseverance. Significant multiple correlations were also found for three criteria of management success. Further research may establish the use of the 16 PF as an aid to management assessment and thereby reduce the costs and time involved in assessment centres. Opsomming Takseersentrums se grootste probleem is gelee in die koste en tyd wat dit behels. Hierdie studie ondersoek die moontlikheid om beide te verminder deur die aanwending van die 16 PF Persoonlikheidsvraelys vir die meting van bestuursdimensies. Belowende resultate is met 'n relatiewe klein steekproef bevind ten opsigte van die voorspelling van inisiatiefen deursettingsvermoe. Beduidende meervoudige korrelasies is ook ten opsigte van drie kriteria van bestuursukses bevind. Verdere navorsing kan die gebruik van die 16 PF as hulpmiddel by bestuursevaluering vestig en sodoende die tydsduur en koste van takseersentrums verminder.

  5. A dosimetric selectivity intercomparison of HDR brachytherapy, IMRT and helical tomotherapy in prostate cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hermesse, Johanne; Biver, Sylvie; Jansen, Nicolas; Coucke, Philippe [Dept. of Radiation Oncology, Liege Univ. Hospital (Belgium); Lenaerts, Eric [Dept. of Medical Physics, Liege Univ. Hospital (Belgium); De Patoul, Nathalie; Vynckier, Stefaan [Dept. of Medical Physics, St Luc Univ. Hospital, Brussels (Belgium); Scalliet, Pierre [Dept. of Radiation Oncology, St Luc Univ. Hospital, Brussels (Belgium); Nickers, Philippe [Dept. of Radiation Oncology, Oscar Lambret Center, Lille (France)

    2009-11-15

    Background and purpose: dose escalation in order to improve the biochemical control in prostate cancer requires the application of irradiation techniques with high conformality. The dosimetric selectivity of three radiation modalities is compared: high-dose-rate brachytherapy (HDR-BT), intensity-modulated radiation radiotherapy (IMRT), and helical tomotherapy (HT). Patients and methods: ten patients with prostate adenocarcinoma treated by a 10-Gy HDR-BT boost after external-beam radiotherapy were investigated. For each patient, HDR-BT, IMRT and HT theoretical treatment plans were realized using common contour sets. A 10-Gy dose was prescribed to the planning target volume (PTV). The PTVs and critical organs' dose-volume histograms obtained were compared using Student's t-test. Results: HDR-BT delivers spontaneously higher mean doses to the PTV with smaller cold spots compared to IMRT and HT. 33% of the rectal volume received a mean HDR-BT dose of 3.86 {+-} 0.3 Gy in comparison with a mean IMRT dose of 6.57 {+-} 0.68 Gy and a mean HT dose of 5.58 {+-} 0.71 Gy (p < 0.0001). HDR-BT also enables to better spare the bladder. The hot spots inside the urethra are greater with HDR-BT. The volume of healthy tissue receiving 10% of the prescribed dose is reduced at least by a factor of 8 with HDR-BT (p < 0.0001). Conclusion: HDR-BT offers better conformality in comparison with HT and IMRT and reduces the volume of healthy tissue receiving a low dose. (orig.)

  6. Robust Estimation of HDR in fMRI using H-infinity Filters

    DEFF Research Database (Denmark)

    Puthusserypady, Sadasivan; Jue, R.; Ratnarajah, T.

    2010-01-01

    Estimation and detection of the hemodynamic response (HDR) are of great importance in functional MRI (fMRI) data analysis. In this paper, we propose the use of three H-infinity adaptive filters (finite memory, exponentially weighted, and timevarying) for accurate estimation and detection of the HDR......-1487]. Performances of the proposed techniques are compared to the conventional t-test method as well as the well-known LMSs and recursive least squares algorithms. Extensive numerical simulations show that the proposed methods result in better HDR estimations and activation detections....

  7. DIE GESKIEDENIS VAN AFDELING LOGISTIEK

    African Journals Online (AJOL)

    1 Aug 1978 ... dan ook aangebied, Agv die probleem wat ont- staan het met die gebrek aan goedgekeurde poste vir die Afdeling en as gevolg van die ver- wagte vertraging met die ondersoek van die. DOS-span, het die Afdeling Logistiek en Afde- ling Personeel oorleg gepleeg en laasgenoemde het ingestem dat die ...

  8. Relocation of a nucletron microselectron-HDR brachytherapy system

    Energy Technology Data Exchange (ETDEWEB)

    Bartrum, T; Tran, T; Freeman, N; Morales, J [St Vincents Hospital, Darlinghurst, NSW (Australia)

    2004-12-15

    Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

  9. Relocation of a nucletron microselectron-HDR brachytherapy system

    International Nuclear Information System (INIS)

    Bartrum, T.; Tran, T.; Freeman, N.; Morales, J.

    2004-01-01

    Full text: For a period of four weeks, our clinical Nucletron microSelectron high dose rate (HDR) brachytherapy system was pulled out of clinical use and relocated to a new building. During this period decommission tests, de-wiring of the treatment unit and its associated safety system (such as radiation detector, emergency off circuits and door interlocks), transportation of all equipment, re-wiring of this equipment in the new location and recommission tests were carried out. The decommission and recommission test program was designed upon consultation with the manufacturer's (Nucletron) acceptance test procedures and work carried out by others. The ACPSEM tolerances for remote afterloaders was used as a guideline. In addition to mandatory dosimetry, positional, workstation database and safety tests, two Australian Standard compliance tests were carried out. The compliance tests involved one for remote afterloaders and another for treatment room design. This testing program was designed and implemented with the aim of ensuring ongoing safe delivery of brachytherapy doses to the patient. The testing program consisted of two parts. The first involved a series of decommissioning tests that consisted of dosimetry tests such as source and check cable positional accuracy and source calibration tests. In addition to these tests an inventory of standard plans, patient records and system configuration information was catalogued. The second part involved a series of recommission tests and involved carrying out dosimetry tests on the brachytherapy system (positional accuracy and calibration tests), simulating common treatment scenarios (prostate, cervical, vaginal and bile duct) and checking standard plans; patient records and system configuration had remained unchanged. During this period, other tests were carried out. These included Nucletron acceptance and preventative maintenance tests, Australian Standards compliance testing and integrity of network transfer of

  10. Commissioning and clinical implementation of HDR brachytherapy in El Salvador

    International Nuclear Information System (INIS)

    Morales Lopez, Jorge Luis; Castillo, Luis Frank; Castillo Bahi, Ramon del

    2009-01-01

    The Gynecologic Cancer is one of the best known malignancies in different countries of the world, with a high incidence in developing countries. In the treatment of this disease have been used multiple treatment arms among which is the high rate brachytherapy (HDR). The IAEA has put much emphasis on supporting all programs to treat this disease and in this context within the project 'Human Resource Development and Nuclear Technology Support', collaborated with the dispatch of experts on mission ELS0006 01 'Assistance to the ICES in HDR brachytherapy initiating Treatments at the Cancer Institute of El Salvador 'Dr. Narciso Diaz Bazan' in San Salvador, El Salvador. The process of commissioning and implementing clinical service Brachytherapy High Dose Rate (HDR BT) is a relatively complex process that begins with the formation of functional and technical service, based on flow patients to be treated, availability of local technological capability to install, and culminates with the preparation and implementation of protocols. Experts involved in the implementation of this service divided this task in stages organized chronologically: 1st. Study of existing infrastructure and level of training of technical personnel available, 2nd. Proposal and application of amendments in order to adapt the facility to the planned patient flow and optimal use of technological infrastructure, 3rd. Establishment of the process of securing the disposable waste materials and not required, 4th. Performance of tests of physical commissioning clinical dosimetry and instrumentation unit, surgical and therapeutic, 5th. Training of technical personnel, 6th. Preparation of clinical protocol and 7th. Initiation and development of treatment for patients. All these steps are carried out with the integration and consensus of the entire multidisciplinary team that makes up the service and with the support of the administration as a prerequisite. Within two weeks the service was modified according to

  11. Die relevansie van die boek Prediker

    African Journals Online (AJOL)

    ook in die dogmatiek te bespeur is nie. 'n Vinnige oorsig oor die teksverwysings van. 'n paar wydgelese dogmatiekhandboeke kan dit bevestig. In Karl Barth se omvang- ryke Kirchliche Dogmatik word Prediker slegs vyf en dertig maal aangehaal en slegs sewe maal word teksgedeeltes bespreek. Emil Brunner haal Prediker ...

  12. Quality assurance of Vari-source high dose rate (HDR) brachytherapy- remote after loader and cost effectiveness of Vari-source HDR- brachytherapy: NORI, Islamabad experience

    International Nuclear Information System (INIS)

    Ahmad, N.; Mahmood, H.; Jafri, S.R.A.

    2004-01-01

    A quality control of Vari-Source high dose rate (HDR) remote after loading brachytherapy machine was carried out and the cost effectiveness of HDR brachytherapy machine was also evaluated considering the cost of ten Iridium-192 wire sources at Nuclear Medicine, Oncology and Radiotherapy Institute (NORI), Islamabad, Pakistan. A total number of 253 intracavitary insertions were done in 98 patients from October 1996 to May 2001. The results of the quality control tests performed during 1996 to 2001 were within the acceptable limits. The cost effectiveness of Vari-Source HDR brachytherapy machine was also evaluated. The average cost per patient was calculated as US$ 491. Small number of patients was treated as the machine was used for gynecologic malignancies only. The objective was to assess the quality control status of HDR brachytherapy machine on patient treatment day, source exchange day and periodic day (monthly basis). It was found that the cost per patient can be minimized if other type of cancer patients are also treated on Vari-Source HDR machine. (author)

  13. HDR flood-water storage-tank modal vibration tests

    International Nuclear Information System (INIS)

    Gorman, V.W.; Thinnes, G.L.

    1983-01-01

    Modal vibration tests were conducted by EG and G Idaho on two vessels located at West Germany's Heissdampfreaktor (HDR) facility which is 25 kilometers east of Frankfurt. The tests were performed during May and June 1982 for the US Nuclear Regulatory Commission (NRC) as part of their cooperative effort with Kernforschungszentrum Karlsruhe (KfK) of West Germany. The primary purpose for performing this task was to determine modal properties (frequencies, mode shapes and associated damping ratios) in order to eventually provide guidelines for standards development by the NRC in modeling similar vessels. One of the vessels tested was a flood water storage tank (FWST) for empty, half full and full water conditions. The FWST was excited randomly with an electromagnetic shaker and by impulsive hammer blows. Excitation or input forces together with measured vessel responses were processed by a digital modal analyzer and stored on magnetic disks for subsequent evaluation

  14. 192Ir high dose rate (HDR) interstitial brain implant: optimisation

    International Nuclear Information System (INIS)

    Tyagi, Anuj; Singh, Dinesh; Chitra, S.; Gupta, J.P.

    2001-01-01

    The new modality of stepping source dosimetry system (SSDs) illustrates a remarkable improvement in attaining the uniform and homogeneous dose distribution within the target volume. The technique enables the physicist to correct for a certain amount of misplacement or curvature of implant geometry. The short course of brachytherapy provides good palliation in terms of functional improvements with low and acceptable toxicity in high-grade glioma. With continual refinements of the technique, brachytherapy performed by a skilled brachytherapy team offers an opportunity to improve patient survival and quality of life. Since 1997, micro selectron HDR 192 Ir treatments are done including gynecological, oesophageal, breast, surface mould, soft tissue sarcoma (STS) and brain in our hospital. In this paper, procedure of interstitial brain implant in glioma as implant technique, simulation and treatment planning will be discussed

  15. P. J. N. Smal, Die Universalisme in die Psalms. Academisch ...

    African Journals Online (AJOL)

    Test

    dat die historiese element in Israel se Godsopenbaring en daarmee die insig in sy betekenis te kort gedoen word. Die betekenis van die studie vir die historia revelationis is daardeur gering; as duidelike „tydlose” sistematisering van Outestamentiese gegewens oor die betrokke onder- werpe, soos die laaste hoofstuk, bl.

  16. DIE ONTVC'ERP VAN 'N SENDINGBELEID IN DIE HUIDIGE ...

    African Journals Online (AJOL)

    Test

    DIE ONTVC'ERP VAN 'N SENDINGBELEID IN DIE. HUIDIGE SITUASIE. Sending is 'n deel van die vervulling van die apostoliese opdrag van die kerk. Dit geskied op grond van en in gehoorsaamheid aan Gods. \\C'oord. Teologiese besinning is daarom die eerste en grondliggende vereiste by die ontwerp van 'n ...

  17. DIE PLEK VAN SANG EN MUSIEK IN DIE PROTESTANTSE ...

    African Journals Online (AJOL)

    Test

    Sy moet hierdie opdrag uitvoer deur mid del van die Prediking d.w.s. deur middel van die Woord-vorm, maar ook deur die bediening van die sakramente, dws. deur middel van die vorm van die Daad. Maar nou wil God nie hê dat die Kerk slegs één maal die Evangelie sal predik en die mense sal doop om hulle daarna.

  18. Packaged die heater

    Science.gov (United States)

    Spielberger, Richard; Ohme, Bruce Walker; Jensen, Ronald J.

    2011-06-21

    A heater for heating packaged die for burn-in and heat testing is described. The heater may be a ceramic-type heater with a metal filament. The heater may be incorporated into the integrated circuit package as an additional ceramic layer of the package, or may be an external heater placed in contact with the package to heat the die. Many different types of integrated circuit packages may be accommodated. The method provides increased energy efficiency for heating the die while reducing temperature stresses on testing equipment. The method allows the use of multiple heaters to heat die to different temperatures. Faulty die may be heated to weaken die attach material to facilitate removal of the die. The heater filament or a separate temperature thermistor located in the package may be used to accurately measure die temperature.

  19. Die radio in Afrika

    Directory of Open Access Journals (Sweden)

    S. de Villiers

    1966-03-01

    Full Text Available Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower.

  20. Transition from LDR to HDR brachytherapy for cervical cancer: Evaluation of tumor control, survival, and toxicity.

    Science.gov (United States)

    Romano, K D; Pugh, K J; Trifiletti, D M; Libby, B; Showalter, T N

    In 2012, our institution transitioned from low-dose-rate (LDR) brachytherapy to high dose-rate (HDR) brachytherapy. We report clinical outcomes after brachytherapy for cervical cancer at our institution over a continuous 10-year period. From 2004 to 2014, 258 women (184 LDR and 74 HDR) were treated with tandem and ovoid brachytherapy in the multidisciplinary management of International Federation of Gynecology and Obstetrics Stages IA-IVB cervical cancer. Clinical and treatment-related prognostic factors including age, stage, smoking status, relevant doses, and toxicity data were recorded. Median followup for the LDR and HDR groups was 46 months and 12 months, respectively. The majority of patients (92%) received external beam radiotherapy as well as concurrent chemotherapy (83%) before the start of brachytherapy. For all stages, the 1-year local control and overall survival (OS) rates were comparable between the LDR and HDR groups (87% vs. 81%, p = 0.12; and 75% vs. 85%, p = 0.16), respectively. Factors associated with OS on multivariate analysis include age, stage, and nodal involvement. On multivariate analysis, severe toxicity (acute or chronic) was higher with HDR than LDR (24% vs. 10%, p = 0.04). Additional prognostic factors associated with increased severe toxicity include former/current smokers and total dose to lymph nodes. This comparative retrospective analysis of a large cohort of women treated with brachytherapy demonstrates no significant difference in OS or local control between the LDR and HDR. Acute and chronic toxicity increased shortly after the implementation of HDR, highlighting the importance of continued refinement of HDR methods, including integrating advanced imaging. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  1. Cost modelling of electricity producing hot dry rock (HDR) geothermal systems in the UK

    International Nuclear Information System (INIS)

    Doherty, P.S.

    1992-03-01

    A detailed and comprehensive cost model for Hot Dry Rock (HDR) electricity producing systems has been developed in this study. The model takes account of the major aspects of the HDR system, parameterized in terms of the main physical and cost parameters of the resource and the utilization system. A doublet configuration is assumed, and the conceptual HDR system which is defined in the study is based upon the UK Department of Energy (DEn) HDR geothermal R and D programme. The model has been used to calculate the costs of HDR electricity for a UK defined base case which represents a consensus view of what might be achieved in Cornwall in the long term. At 14.2 p/kWh (1988 costs) this cost appears to be unacceptably high. A wide-ranging sensitivity study has also been carried out on the main resource, geometrical, and operational parameters of the HDR system centred around the UK base case. The sensitivity study shows the most important parameters to be thermal gradient and depth. (Author)

  2. Die Erfindung des Manuskripts

    DEFF Research Database (Denmark)

    Benne, Christian

    Die Entstehung der literarischen Moderne ging seit dem 18. Jahrhundert damit einher, dass die Anzahl literarischer Manuskripte ebenso wuchs wie deren Bedeutung. Der Buchdruck hatte die Handschrift keineswegs überflüssig gemacht, sondern provozierte im Gegenteil einen neuen, am Autographen...

  3. Die begrafnisdíens

    African Journals Online (AJOL)

    Num 20: 1; Jos 24: 30; Hand 5: 5 - 11). Selfs van die ... Gebruike rondom die begrafnis het van geslag tot geslag gewissel. De Vaux ... der geskied deur die hoorders 'te onderrig, te vermaan, te vertroos en te bestraf, soos dit in elke geval ..... gehandhaaf hoef te word, veral in die lig van die feit dat die predikant die kerklike.

  4. Die gebruik van parallelplaatreologie vir die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat

    Directory of Open Access Journals (Sweden)

    O. C. Vorster

    2005-09-01

    Full Text Available Die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat word bemoeilik deur die feit dat daar tans slegs twee metodes in gebruik is. In die eerste metode word die bepaling deur middel van oplossingsviskometrie gedoen, maar die toksisiteit van die oplosmiddel, asook die tydperk wat dit neem om die bepaling te doen, is ’n probleem. Die tweede metode word beperk deur die kompleksiteit en beskikbaarheid van die apparatuur in Suid-Afrika. In hierdie studie word ’n alternatiewe metode, gebaseer op parallelplaatreologie, voorgestel wat albei hierdie probleme oorkom en die resultate sodoende verkry, word vergelyk met dié wat met bestaande metodes verkry is.

  5. Die invloed van die neo-marxistiese kultuuranalise op die Wêreldraad van Kerke en die Gereformeerde Kerke van Nederland

    Directory of Open Access Journals (Sweden)

    J. M. Vorster

    1979-05-01

    Full Text Available Toe die studente dwarsoor die VSA en Europa in die laat sestigerjare ’n plotselinge en radikale verset openbaar het teen die bestaande orde, het hulle die deur geopen vir ’n nuwe mededinger om die hart van die Westerse kultuur. Dit is die nou reeds bekende neo-Marxisme. Sedertdien het hierdie jongeling sy voetspore op vele vlakke van die Westerse kultuur gelaat.

  6. die pers as bron oor die geskiedenis van die eerste vrydeidsoorlog

    African Journals Online (AJOL)

    dood agv wonde wat hy tydens die slag opgedoen het. Dit was vir die Britse volk onaanvaarbaar dat slegs twee Boere gedood is nadat daar tussen. 20 000 en 30 000 rondtes op die Boere afgevuur is. Die pers kon net nie die ware syfers publiseer nie, want dit sou na 'n onwaarheid Iyk. Het die. Britse volk egter die Boere ...

  7. die impak van metodologie op die verstaan van die nuwe testament

    African Journals Online (AJOL)

    voorbeeld eers een maal deur die bril van die vorm- en redaksiekritiek na die Evangelies gekyk het, dink jy vir altyd anders oor hulle tot- standkoming. Inderdaad, nuwe metodes lei tot nuwe perspektiewe! Dit is dan ook waar die fokus van hierdie artikel val: die impak van metodologie op die verstaan van die Nuwe ...

  8. Verskuiwing in die moraal?

    Directory of Open Access Journals (Sweden)

    S.P. van der Walt

    1974-03-01

    Full Text Available Modewoorde het ons deesdae oorgenoeg in die Christelike sedeleer en hulle kan nogal verwarring stig. U moet my vergun om met u te spreek oor een so ’n modewoord nl „verskuiwing’’ in die moraal. Dis nogal ’n mooi woord, wat so dikwels gebruik word op baie terreine en tog meer wil aandui as maar net ’n veranderde sienswyse, ’n wysiging in opvattinge of nuwe riglyne wat al gangbaar geword het in die praktyk. Die begrip wil eintlik die ewolusionêre gang beklemtoon, want dit is dan eintlik net die ou norme wat effens anders bekyk word of nie meer so nou geneem of dik onderstreep word nie. Die verskuiwing beteken dan dat alles nog dieselfde bly, net die posisie of plek het verander. Verskuiwing beteken tog plekverandering of plekwisseling en dan sekerlik nie in die sin dat die plekke ver uitmekaar lê nie. Verskuiwing beteken net maar vlak langs die vorige te staan kom. As dit dan ’n beter plek is, is dit ewolusie, ontwikkeling, verbetering.

  9. The relative efficacy of HDR and LDR interstitial brachytherapy in squamous cell carcinoma of vagina

    International Nuclear Information System (INIS)

    Demanes, D. J.; Hsu, I-C.; Lin, S.; Ewing, T.; Rodriguez, R.

    1996-01-01

    Introduction: Beginning in 1982 we performed low dose rate (LDR) interstitial template brachytherapy (ISTB) for carcinoma of the vagina. High dose rate (HDR) remote afterloading has been used exclusively since 1991. We compare the results LDR and HDR brachytherapy. Material and Methods: Between 1982 and 1994, 30 patients with primary squamous cell carcinoma of vagina received external beam radiotherapy (EBRT) and brachytherapy. The AJCC stage distribution was 3 stage I, 25 stage II, and 2 stage III. The average central pelvic EBRT dose was 35 Gy. Pelvic side wall EBRT doses ranged from 45 to 50.4 Gy. Nineteen patients had LDR treatment; 3 intracavitary brachytherapy (ICB) and 16 ISTB. Eleven patients had HDR treatment; 2 ICB and 9 ISB. The average dose delivered by LDR was 41.2 Gy usually in 2 fractions, and by HDR 32.5 Gy in 6 fractions of 500-550 cGy. Local failures were confirmed pathologically. The absolute survival (AS) and relapse-free survival (RFS) were calculated using Kaplan-Meier method and compared with logrank statistics. Results: The mean follow-up was 77 months for LDR and 23 months for HDR. Local and regional control was achieved in 90% (27/30) of the patients. Three year AS was 84% and RFS was 87%. There was no significant difference between LDR and HDR in AS, RFS or local-regional control, (log rank p=0.85, p=0.12 and p=0.35 respectively). The single HDR local failure presented in a patient with extensive stage II disease who declined ISTB. There were fewer complications following HDR. The 1 case of extensive vaginal necrosis and the 3 cases of rectovaginal fistula that required surgery occurred only with LDR brachytherapy. Discussion: Excellent local and regional control of carcinoma of the vagina can be achieved by administering limited doses of external radiation and brachytherapy. Interstitial template implants are the best means of encompassing paravaginal disease while sparing the adjacent uninvolved normal tissues from high doses of

  10. oor die inhoud en boodskap van die heidelbergse kategismus

    African Journals Online (AJOL)

    Smit. Oor die Inhoud en Boodskap van die Heidelbergse Kategismus. 52. Uiteraard sal dié tema saamhang met die bedoelinge agter die opstel van die Kategismus. Ook die vraag na moontlike bedoelinge of motiewe is egter 'n ingewikkelder vraag as wat miskien gedink mag word. Uiteraard was daar agter elke kategismus ...

  11. Thomas Erastus oor die struktuur van die gemeenskap'^

    African Journals Online (AJOL)

    óók aansprake en regte het, is die opvatting dat sowel die burgerlike gemeenskap as die kerk 'n perfecta societas sibi sufficiens is, nié werklik aanvaar nie. Die Middeleeuse gemeenskap was die corpus christianum,. 'n gemeenskap wat nie deur fisiese of politieke grense beperk was nie. Sy grense het gelê waar die grense ...

  12. die doel en wese van opvoedende onderwys en die implikasies

    African Journals Online (AJOL)

    Oaar moet onderskei word tussen die doelstellings van opvoedende onderwys en die einddoel wat bereik word deur die nastrewing van hierdie doelstellings. Gunter praat van die naderliggende doelstellings (1981, b1.105). \\/at die enddoel van opvoedende onderwys bet ref, gaan die meeste opvoedkundi ges akkoord dat ...

  13. Comparison of radiation shielding requirements for HDR brachytherapy using 169Yb and 192Ir sources

    International Nuclear Information System (INIS)

    Lymperopoulou, G.; Papagiannis, P.; Sakelliou, L.; Georgiou, E.; Hourdakis, C. J.; Baltas, D.

    2006-01-01

    169 Yb has received a renewed focus lately as an alternative to 192 Ir sources for high dose rate (HDR) brachytherapy. Following the results of a recent work by our group which proved 169 Yb to be a good candidate for HDR prostate brachytherapy, this work seeks to quantify the radiation shielding requirements for 169 Yb HDR brachytherapy applications in comparison to the corresponding requirements for the current 192 Ir HDR brachytherapy standard. Monte Carlo simulation (MC) is used to obtain 169 Yb and 192 Ir broad beam transmission data through lead and concrete. Results are fitted to an analytical equation which can be used to readily calculate the barrier thickness required to achieve a given dose rate reduction. Shielding requirements for a HDR brachytherapy treatment room facility are presented as a function of distance, occupancy, dose limit, and facility workload, using analytical calculations for both 169 Yb and 192 Ir HDR sources. The barrier thickness required for 169 Yb is lower than that for 192 Ir by a factor of 4-5 for lead and 1.5-2 for concrete. Regarding 169 Yb HDR brachytherapy applications, the lead shielding requirements do not exceed 15 mm, even in highly conservative case scenarios. This allows for the construction of a lead door in most cases, thus avoiding the construction of a space consuming, specially designed maze. The effects of source structure, attenuation by the patient, and scatter conditions within an actual treatment room on the above-noted findings are also discussed using corresponding MC simulation results

  14. Preliminary results of study comparing HDR with LDR brachytherapy for IIIb cervical cancer

    International Nuclear Information System (INIS)

    Trippe, N.; Pellizzon, A.C.A.; Novaes, P.; Salvajoli, J.V.; Fogaroli, R.; Maia, M.A.C.; Baraldi, H.; Ferrigno, R.

    1996-01-01

    Since 1992 we have been using a Micro-Selectron HDR device, working with Iridium 192 to treat the cervical cancer and some others pathologies. With a minimum follow up of 24 months, 59 patients with cervical cancer were randomizated for one of the following schedule of treatment: EBRT - 45Gy - fx 1,8Gy plus Brachytherapy 1-HDR - 36 (61%) - 4 weekly insertions of 6,0Gy at point A 2-LDR - 29 (39%) - two insertions fifteen days apart of 17,5Gy at point A EBRT was performed with a Linac 4MV, in box arrangement and parametrial complementation of dose with AP-PA fields. For Brachytherapy Fletcher Colpostats are used in association with intrauterine tamdens, in both arms. Brachyterapy starts in HDR group after ten days of the beginning of the treatment. The total time of treatment is shortened here in two weeks. LDR brachytherapy starts only after the end of EBRT. Results - local control was 61% in 12 months and 50% in 24 months for HDR group, versus 52,6% and 47,8% for LDR group. Local failures of 39% and 50% in 12 and 24 months for HDR and 47,8% and 52,8% for LDR groups respectively. Complications were restricted to rectites and cistites - 8,3% for HDR and 13% for LDR. Conclusions - HDR brachytherapy has an equivalent local control when compared to LDR, can treat a larger number of patients in a shorter period, has possibilities of dose optimizations and decrease the radiation exposure to the staff

  15. MR-based source localization for MR-guided HDR brachytherapy

    Science.gov (United States)

    Beld, E.; Moerland, M. A.; Zijlstra, F.; Viergever, M. A.; Lagendijk, J. J. W.; Seevinck, P. R.

    2018-04-01

    For the purpose of MR-guided high-dose-rate (HDR) brachytherapy, a method for real-time localization of an HDR brachytherapy source was developed, which requires high spatial and temporal resolutions. MR-based localization of an HDR source serves two main aims. First, it enables real-time treatment verification by determination of the HDR source positions during treatment. Second, when using a dummy source, MR-based source localization provides an automatic detection of the source dwell positions after catheter insertion, allowing elimination of the catheter reconstruction procedure. Localization of the HDR source was conducted by simulation of the MR artifacts, followed by a phase correlation localization algorithm applied to the MR images and the simulated images, to determine the position of the HDR source in the MR images. To increase the temporal resolution of the MR acquisition, the spatial resolution was decreased, and a subpixel localization operation was introduced. Furthermore, parallel imaging (sensitivity encoding) was applied to further decrease the MR scan time. The localization method was validated by a comparison with CT, and the accuracy and precision were investigated. The results demonstrated that the described method could be used to determine the HDR source position with a high accuracy (0.4–0.6 mm) and a high precision (⩽0.1 mm), at high temporal resolutions (0.15–1.2 s per slice). This would enable real-time treatment verification as well as an automatic detection of the source dwell positions.

  16. SU-F-BRA-04: Prostate HDR Brachytherapy with Multichannel Robotic System

    International Nuclear Information System (INIS)

    Joseph, F Maria; Podder, T; Yu, Y

    2015-01-01

    Purpose: High-dose-rate (HDR) brachytherapy is gradually becoming popular in treating patients with prostate cancers. However, placement of the HDR needles at desired locations into the patient is challenging. Application of robotic system may improve the accuracy of the clinical procedure. This experimental study is to evaluate the feasibility of using a multichannel robotic system for prostate HDR brachytherapy. Methods: In this experimental study, the robotic system employed was a 6-DOF Multichannel Image-guided Robotic Assistant for Brachytherapy (MIRAB), which was designed and fabricated for prostate seed implantation. The MIRAB has the provision of rotating 16 needles while inserting them. Ten prostate HDR brachytherapy needles were simultaneously inserted using MIRAB into a commercially available prostate phantom. After inserting the needles into the prostate phantom at desired locations, 2mm thick CT slices were obtained for dosimetric planning. HDR plan was generated using Oncetra planning system with a total prescription dose of 34Gy in 4 fractions. Plan quality was evaluated considering dose coverage to prostate and planning target volume (PTV), with 3mm margin around prostate, as well as the dose limit to the organs at risk (OARs) following the American Brachytherapy Society (ABS) guidelines. Results: From the CT scan, it is observed that the needles were inserted straight into the desired locations and they were adequately spaced and distributed for a clinically acceptable HDR plan. Coverage to PTV and prostate were about 91% (V100= 91%) and 96% (V100=96%), respectively. Dose to 1cc of urethra, rectum, and bladder were within the ABS specified limits. Conclusion: The MIRAB was able to insert multiple needles simultaneously into the prostate precisely. By controlling the MIRAB to insert all the ten utilized needles into the prostate phantom, we could achieve the robotic HDR brachytherapy successfully. Further study for assessing the system

  17. Die tug oor ampsdraers tydens die doleansie van 1886

    Directory of Open Access Journals (Sweden)

    J. Visser

    1986-06-01

    Full Text Available In art 29 van die Nederlandse Geloofsbelydenis word bely: “Die merktekens om die ware Kerk te ken is die volgende: As die Kerk die suiwere prediking van die evangelie uitoefen, as dit die suiwer bediening van die sakramente gebruik soos Christus dit ingestel het, as die kerklike tug gebruik word om die sondes te straf.” Dit spreek vanself dat wanneer ampsdraers, aan wie Christus sy kudde toevertrou het (Hand 20 : 28, met leer en /of lewenswandel in sonde volhard en nie daarin met tug gestuit word nie, word die ware kerk nie gebou nie maar afgebreek. 0ns sal later in hierdie artikel aantoon hoedanig die suiwer tug oor ampsdraers, veral leertug, tydens die Doleansie tot skade van die kerk van Christus agterweë gebly het.

  18. Requirements tests for QC of microSelectron-HDR

    International Nuclear Information System (INIS)

    Gesheva-Atanasova, N.; Gogova, A.; Peycheva, S.; Constantinov, B.; Ganchev, M.

    2000-01-01

    The Quality Control (QC) considers checks and measurements with the purpose of reconstruction, maintaining and increasing the quality of medical procedures and equipment. The QC tests for micro Selectron HDR afterloading machine with 192 Ir which allows more precise calculation and realisation of the tumour's dose have been created and introduced regularly in National Oncological Centre, Sofia. This paper has been cover the machine and software performance, source positioning, application equipment and radiation safety. A list of tests, their frequency, tolerance and action levels, as well as the tests' procedures have been worked out. The used methods are based on establishment of QC protocols. The documents have achieved for a certain period of time and they are available at any time. The experience shows drastically reduction of failures during medical treatment, ensuring the reliability of the used equipment and confidence that all the patients have treated adequate. Where some parameter is above the tolerance is it possible to do proper corrections measures immediately. This QA protocols give assurance that specific objectives being successfully met

  19. Die metafoor by Breyten Breytenbach

    African Journals Online (AJOL)

    Owner

    23 Jun 2009 ... metafories, of spesifiek verwysend, te werk gegaan is. Tyd sou mens die hoofmotief van die bundel noem, tyd en geheue wat verbygaan: 1 en 2; en die einde van die storie wat gekom het: “fluit-fluit my storie is uit”. (Die tema van verbygaan word weer opgeneem in 8 en 9: die stories wat nooit meer gehoor ...

  20. IRAN IN DIE INTERNASIONALE MAGSTRYD

    African Journals Online (AJOL)

    In die verband kan genoem word dat die Russe nog grotendeels gebruik maak van 'n metode waarvolgens water in die oliestratum gepomp word om 'n opwaartse druk van ru-olie te verseker; een nadeel hiervan is dat die water mettertyd deur die oliehoudende laag ontsnap en agv die drukverlies isvoortgesette ontginning.

  1. Die singulation method

    Science.gov (United States)

    Swiler, Thomas P.; Garcia, Ernest J.; Francis, Kathryn M.

    2013-06-11

    A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with an HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.

  2. Ontsporing van die regstaatsbegrip en sy konsekwensies vir die afrikanervolk

    Directory of Open Access Journals (Sweden)

    N. G.S. Van der Walt

    1966-03-01

    Full Text Available Die opvatting van die suiwere regstaat bring sy vraagstukke mee wanneer dit in verband gebring word met die leer van die soewereiniteit in eie kring. Laasgenoemde leer wortel in die geloof dat God die mens roep tot diens aan Hom, en dat die mens vry moet wees om ten opsigte van alle lewensaspekte God na die hoogste mate te kan dien. Hierdie verskeidenheid van aspekte is deur dr. A. Kuyper en sy volgelinge gesistemati- seer tot menslike verbande en lewenskringe, elk met ’n be- paalde sfeer waarin ander kringe nie mag inmeng nie. Elkeen is dan soewerein binne sy eie kring. Met verwysing na die staat is dan gespreek van die staatstaak as synde die hand- hawing van die reg, en omdat die staat in toenemende mate hom veral in die latere tyd ook besig gehou het met bedrywig- hede wat nouliks as van juridiese aard beskou kan word, is daar die onderskeid gemaak tussen die primêre en sekundêre taak van die staat. Die sistematiek van die wetsidee, deur prof. Dooyeweerd ontwikkel, waar die staat sy bestemmingsfunksie in die regsaspek vind, het vanselfsprekend geen plek vir so 'n dualistiese staatstaak nie, en die oplossing is deur sommige daarin gesoek om sulke staatsoptrede te vertolk as hebbende wel betrekking op die regsgemeenskap of die regsverkeer. Staatsondernemings soos paaie, spoorweë, spellingreëling, ens. word dan beskou as noodsaaklik vir die instandhouding van die regsgemeenskap en regsverkeer. Tereg wys A. M. Donner1 daarop dat so ’n vertolking eintlik neerkom op ’n oorspanning van die regsbegrip. Hy self sien dan die staatstaak in vrede- of orde-handhawing, wat in die eerste plaas wel regshandha- wing veronderstel. Onder orde word dan alles verstaan wat noodsaaklik is vir die gladde verkeer in die ontwikkelingsgang van die regsgemeenskap. Die wese van die staat het dan vol- gens hom te doen met reg, maar sy taak is meer as suiwere regshandhawing. Wat onrus verwek en die orde versteur, moet uit die openbare lewe verwyder word, en die

  3. Die sterwende kindjie

    Directory of Open Access Journals (Sweden)

    J.T. De Jongh van Arkel

    1983-09-01

    Full Text Available The thought of a child dying appears as an antithesis and thus the feelings evoked by the dying child are stronger than when older persons are dying. Around the child’s death bed there is no place for detached spectators and all become involved in caring for and supporting him. Caregivers also have a supporting responsibility towards the members of the child’s family.

  4. Analise van die Tswanaraaisel

    Directory of Open Access Journals (Sweden)

    S. A. Swanepoel

    1984-05-01

    Full Text Available ’n Strukturele, stilistiese en funksionele bcskrywing van die Twanaraaisel bring mee dat daar aan die volgende aspekte aandag gegee moet word: •\tWat is ’n raaisel en lioe word dit in Tswana genoem. •\tTot watter studiegebied en literere genre hoort die raaisel en watter subvorme kan vir Tswana onderskei word. •\tHoe sien die struktuur van Tswanaraaisels daar uit. •\tDeur wie, waar, wanneer en hoe word Tswanaraaisels voorgedra. •\tWatter stilistiese kenmcrke kan in Tswanaraaisels onderskei word. •\tWatter funksies vervul raaisels in ’n Tswanagcmeenskap.

  5. The Angry Dying Patient.

    Science.gov (United States)

    Houston, Robert E.

    1999-02-01

    Over 25 years ago, Kubler-Ross identified anger as a predictable part of the dying process. When the dying patient becomes angry in the clinical setting, all types of communication become strained. Physicians can help the angry dying patient through this difficult time by using 10 rules of engagement. When physicians engage and empathize with these patients, they improve the patient's response to pain and they reduce patient suffering. When physicians educate patients on their normal responses to dying and enlist them in the process of family reconciliation, they can impact the end-of-life experience in a positive way.

  6. LDR vs. HDR brachytherapy for localized prostate cancer: the view from radiobiological models.

    Science.gov (United States)

    King, Christopher R

    2002-01-01

    Permanent LDR brachytherapy and temporary HDR brachytherapy are competitive techniques for clinically localized prostate radiotherapy. Although a randomized trial will likely never be conducted comparing these two forms of brachytherapy, a comparative radiobiological modeling analysis proves useful in understanding some of their intrinsic differences, several of which could be exploited to improve outcomes. Radiobiological models based upon the linear quadratic equations are presented for fractionated external beam, fractionated (192)Ir HDR brachytherapy, and (125)I and (103)Pd LDR brachytherapy. These models incorporate the dose heterogeneities present in brachytherapy based upon patient-derived dose volume histograms (DVH) as well as tumor doubling times and repair kinetics. Radiobiological parameters are normalized to correspond to three accepted clinical risk factors based upon T-stage, PSA, and Gleason score to compare models with clinical series. Tumor control probabilities (TCP) for LDR and HDR brachytherapy (as monotherapy or combined with external beam) are compared with clinical bNED survival rates. Predictions are made for dose escalation with HDR brachytherapy regimens. Model predictions for dose escalation with external beam agree with clinical data and validate the models and their underlying assumptions. Both LDR and HDR brachytherapy achieve superior tumor control when compared with external beam at conventional doses (LDR brachytherapy as boost achieves superior tumor control than when used as monotherapy. Stage for stage, both LDR and current HDR regimens achieve similar tumor control rates, in agreement with current clinical data. HDR monotherapy with large-dose fraction sizes might achieve superior tumor control compared with LDR, especially if prostate cancer possesses a high sensitivity to dose fractionation (i.e., if the alpha/beta ratio is low). Radiobiological models support the current clinical evidence for equivalent outcomes in localized

  7. Die brein soos beskou deur die Grieke en Romeine

    Directory of Open Access Journals (Sweden)

    Francois P. Retief

    2015-02-01

    Full Text Available In Ou Egipte is mummifikasie met uitgebreide reseksie of uitsnyding van organe geassosieer, maar geen kennis is geneem van die morfologie van die brein nie. Griekse skrywers van die sesde en vyfde eeue v.C. het die brein aanvanklik gesien as die setel van intelligensie, die orgaan van sensoriese waarneming en gedeeltelik die oorsprong van sperma. Pneuma het ’n belangrike rol in breinfunksie gespeel. Hippokrates was die eerste om die brein te beskryf as ’n dubbele orgaan, wat met harsingvlies (meninges bedek, funksioneel van pneuma afhanklik en vertolker van begrip is. Tydgenote soos Plato, Aristoteles en Diokles het tot die beskrywing bygedra, maar laasgenoemde twee het beweer dat die hart die middelpunt van intelligensie is en nie die brein nie. Gedurende die laaste helfte van die vierde eeu v.C. is disseksie van die menslike liggaam tydelik aan die mediese skool van Alexandrië toegelaat en het dit tot merkwaardige vooruitgang in die begrip van die menslike anatomie en fisiologie gelei. Herofilus en Erasistratus het uitstekende beskrywings van die struktuur en funksie van die brein gegee wat eers in die tweede eeu n.C. deur Galenus geëwenaar is.

  8. DIE SUID-AFRIKAANSE JEUG IN VOORTREKKERTYDPERK

    African Journals Online (AJOL)

    dien. Die planke en velie moes keer dat die assegaaie die mense tref. Voor die geveg het die vrouens en groter dogters koeels gegiet. Tydens die geveg het die seuns gehelp skiet terwyl die vrouens en dogters die gewere vir die mans gelaai het. Van die dogters soos Nellie. Botha (11 jaar oud) en haar sussie Fya (15 jaar.

  9. Dose rate considerations in brachytherapy: biological equivalence of LDR and HDR

    International Nuclear Information System (INIS)

    Orton, C.G.

    1994-01-01

    The linear-quadratic model for cell survival and bioeffect doses is discussed and equations for low dose rate (LDR), high dose rate (HDR) and intermediate situations are presented. The model, when used to define LDR and single fractions of HDR, shows, that these correspond to irradiations lasting longer than about 14 hours or shorter than about 0.7 hours, respectively. It is shown that, for HDR to be as safe and effective as LDR, the dose-rate effect of LDR has to be replaced by the fractionation-effect of HDR. This is necessary in order to take advantage of the differential repair characteristics between late-reacting normal tissue and tumor cells at low doses and low dose rates. Using the linear-quadratic model to simulate repair mathematically, it is shown that the number of fractions required is highly dependent upon what parameters are assumed for normal tissues and tumor, as well as whether or not there is any physical advantage gained by conversion from LDR to HDR. (author). 20 refs., 7 figs

  10. Evaluation of a HDR image sensor with logarithmic response for mobile video-based applications

    Science.gov (United States)

    Tektonidis, Marco; Pietrzak, Mateusz; Monnin, David

    2017-10-01

    The performance of mobile video-based applications using conventional LDR (Low Dynamic Range) image sensors highly depends on the illumination conditions. As an alternative, HDR (High Dynamic Range) image sensors with logarithmic response are capable to acquire illumination-invariant HDR images in a single shot. We have implemented a complete image processing framework for a HDR sensor, including preprocessing methods (nonuniformity correction (NUC), cross-talk correction (CTC), and demosaicing) as well as tone mapping (TM). We have evaluated the HDR sensor for video-based applications w.r.t. the display of images and w.r.t. image analysis techniques. Regarding the display we have investigated the image intensity statistics over time, and regarding image analysis we assessed the number of feature correspondences between consecutive frames of temporal image sequences. For the evaluation we used HDR image data recorded from a vehicle on outdoor or combined outdoor/indoor itineraries, and we performed a comparison with corresponding conventional LDR image data.

  11. Highly efficient CRISPR/HDR-mediated knock-in for mouse embryonic stem cells and zygotes.

    Science.gov (United States)

    Wang, Bangmei; Li, Kunyu; Wang, Amy; Reiser, Michelle; Saunders, Thom; Lockey, Richard F; Wang, Jia-Wang

    2015-10-01

    The clustered regularly interspaced short palindromic repeat (CRISPR) gene editing technique, based on the non-homologous end-joining (NHEJ) repair pathway, has been used to generate gene knock-outs with variable sizes of small insertion/deletions with high efficiency. More precise genome editing, either the insertion or deletion of a desired fragment, can be done by combining the homology-directed-repair (HDR) pathway with CRISPR cleavage. However, HDR-mediated gene knock-in experiments are typically inefficient, and there have been no reports of successful gene knock-in with DNA fragments larger than 4 kb. Here, we describe the targeted insertion of large DNA fragments (7.4 and 5.8 kb) into the genomes of mouse embryonic stem (ES) cells and zygotes, respectively, using the CRISPR/HDR technique without NHEJ inhibitors. Our data show that CRISPR/HDR without NHEJ inhibitors can result in highly efficient gene knock-in, equivalent to CRISPR/HDR with NHEJ inhibitors. Although NHEJ is the dominant repair pathway associated with CRISPR-mediated double-strand breaks (DSBs), and biallelic gene knock-ins are common, NHEJ and biallelic gene knock-ins were not detected. Our results demonstrate that efficient targeted insertion of large DNA fragments without NHEJ inhibitors is possible, a result that should stimulate interest in understanding the mechanisms of high efficiency CRISPR targeting in general.

  12. A Survey on the Acceptance and the Use of HDR Photography Among Croatian Photographers

    Directory of Open Access Journals (Sweden)

    Maja Strgar Kurecic

    2013-04-01

    Full Text Available The emerging field of high dynamic range (HDR imaging is directly linked to diverse existing disciplines such as radiometry, photometry, colorimetry and colour appearance - each dealing with specific aspects of light and its perception by humans. Although the idea is not new, it has not been widely used until just a few years ago when digital cameras gained popularity and the computers processing power increased significantly. Now this photographic technique is widely spread and used, but even more often – misused. A research was conducted by means of a questionnaire in order to get some actual information about how Croatian photographers see the HDR photography and how they employ it. The results of the survey proved that indeed a great interest exists in the technique, but that many photographers are scared away from the HDR photography because of the misconception that the artificial look is an unavoidable side effect of the HDR processing. The fact is, however, that the final HDR image is a result of the tone mapping process and post-corrections and adjustments, entirely dependent on the photographer’s intent and vision, as well as his understanding of various adjustments available. The results of the questionnaire have also pointed out to other widely spread misconceptions which are discussed in this paper.

  13. Die uitbouing van die Bybelse kanon in antieke Judaïsme en die ...

    African Journals Online (AJOL)

    31 Jul 2015 ... die oer-Christelike boodskap tot by sy Ou Testamentiese wortels, die geskrifte van Israel wat cum grano salis die 'Bybel' van die oer-Christendom geword het en die blywende verwysingspunt van die Christelike boodskap is. Erkenning. Hierdie artikel is vertaal na Afrikaans deur Prof. Jan G. van der Watt.

  14. Die opleiding van bedryfsielkundiges aan die universiteit van Fort Hare

    Directory of Open Access Journals (Sweden)

    W. Botha

    1977-11-01

    Full Text Available Die Departement Bedryfsielkunde aan die Universiteit van Fort Hare is 'n relatiewe jong departement en het eers in 1965 tot stand gekom. Voor hierdie datum is Bedryfsielkunde as 'n kort kursus deur die departement van suiwer Sielkunde aangebied en een van die destydse dosente, Dr. W. Backer, het die inisiatief geneem om 'n selfstandige departement van Bedryfsielkunde in die Fakulteit van Ekonomiese Wetenskappe op die been te bring.

  15. Oor die Bybel in die Afrikaanse digkuns

    African Journals Online (AJOL)

    another. As a matter of fact, the development of Afri kaans, the instrument of the poet, has been significantly influenced the Afrikaans translation of the Bible. Belie ... ook gesê het: Saam met ons literatuur, so oud as hy is. Die eerste Afrikaanse digter by wie ons omvattende Bybelse invloed kry, is. Totius, een van ons vroegste ...

  16. Towards real-time 3D ultrasound planning and personalized 3D printing for breast HDR brachytherapy treatment

    International Nuclear Information System (INIS)

    Poulin, Eric; Gardi, Lori; Fenster, Aaron; Pouliot, Jean; Beaulieu, Luc

    2015-01-01

    Two different end-to-end procedures were tested for real-time planning in breast HDR brachytherapy treatment. Both methods are using a 3D ultrasound (3DUS) system and a freehand catheter optimization algorithm. They were found fast and efficient. We demonstrated a proof-of-concept approach for personalized real-time guidance and planning to breast HDR brachytherapy treatments

  17. calvyn oor die leiding van die heilige gees in die verklaring van die

    African Journals Online (AJOL)

    Mittel alters, bis er zur Ruhe kommt bei den kanonischen Schriften der. Urzeit der christlichen Ära (Barth ... (ego tamen dimoveri non possum ab amore compendii, CO 10, 403). Deur die boodskap van die .... Idem ergo spiritus qui per os prophetarum loquutus est, in corda nostra penetret necesse est, ut persuadeat fideliter ...

  18. KERKWEES IN DIE

    African Journals Online (AJOL)

    Acta Theologica is an accredited South. African journal publishing ... SciELO South Africa. REDAKSIE/ ... 'n persoon belydenis van geloof af wat instemming met die betrokke kerk se ...... Ek was na my ongeluk buite aksie en op Clarens. 'n Mede-lid ...... Die “formation of new confessions, change to current confessions, and.

  19. Dying with dignity

    OpenAIRE

    S P Kalantri

    2003-01-01

    The concept of dignity has beeen one of the ambiguous concepts in biomedical ethics. Thus the ambiguous nature of this concept has been extended to what it means to die with dignity. This research work is an investigation into the complexity in the understanding of "dying with dignity" in Applied Ethics.

  20. The day Madiba died

    African Journals Online (AJOL)

    8 Apr 2016 ... shibien en ma is nie happy nie. Susan Gaigher se allegoriese fanta- sie- oftewel wetenskapsfiksieverhale. “Martine se teepot” (46–55) en “Maslow”. (56–67) is verfrissend. Gaigher is een van die min skrywers in die bundel wat 'n kenmerkende en oorspronklike stem laat klink. 'n Mens sal 'n Gaigher-verhaal.

  1. Die entwicklung, die metamorphose, die entstehung: Die konzepte des organismus von Aristoteles bis Darwin

    Directory of Open Access Journals (Sweden)

    Kamerer Eva

    2009-01-01

    Full Text Available (nemački In diesem Aufsatz versuche ich, die Elemente verschiedener Konzepte des Organismus in der Philosophie und in der Wissenschaft zu analysieren. Die Deutungen des Organismus und der Einheit der Natur bei Aristoteles, Kant und Goethe werden als ein Beispiel der Bewegung von einem finalistischen zum antifinalistischen Bild der Natur verstanden.

  2. HDR imaging and color constancy: two sides of the same coin?

    Science.gov (United States)

    McCann, John J.

    2011-01-01

    At first, we think that High Dynamic Range (HDR) imaging is a technique for improved recordings of scene radiances. Many of us think that human color constancy is a variation of a camera's automatic white balance algorithm. However, on closer inspection, glare limits the range of light we can detect in cameras and on retinas. All scene regions below middle gray are influenced, more or less, by the glare from the bright scene segments. Instead of accurate radiance reproduction, HDR imaging works well because it preserves the details in the scene's spatial contrast. Similarly, on closer inspection, human color constancy depends on spatial comparisons that synthesize appearances from all the scene segments. Can spatial image processing play similar principle roles in both HDR imaging and color constancy?

  3. WE-G-BRC-02: Risk Assessment for HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Mayadev, J. [UC Davis Comprehensive Cancer Center (United States)

    2016-06-15

    Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, the medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic.

  4. Transillumination and HDR Imaging for Proximal Caries Detection.

    Science.gov (United States)

    Lederer, A; Kunzelmann, K H; Hickel, R; Litzenburger, F

    2018-02-01

    The purpose was to develop an in vitro model for the validation of near-infrared transillumination (NIRT) for proximal caries detection, to enhance NIRT with high-dynamic-range imaging (HDRI), and to compare both methods, using micro-computed tomography (µCT) as a reference standard. Both proximal surfaces of 53 healthy or decayed permanent human teeth were examined using the Diagnocam (DC) (KaVo) and NIRT with HDRI (NIRT-HDRI). NIRT was combined with HDRI to improve the diagnostic performance by reducing under- and overexposed image areas. For NIRT-HDRI, an exposure series was captured and merged into a single HDR image. A classification was applied according to lesion depth. All surfaces were assessed twice by 2 trained examiners, and additionally with µCT for validation. The Kappa statistic was used to calculate inter-rater reliability and agreement between DC and NIRT-HDRI. Inter-rater reliability (weighted Kappa, wκ) showed very good agreement for the DC (0.90) and NIRT-HDRI (0.96). The overall agreement (wκ) was almost perfect (0.85). In the individual categories (0 to 4), the agreement (simple Kappa) ranged from almost perfect (category 4) to moderate (1 and 2) to substantial (categories 0 and 3). Sensitivity and specificity of sound surfaces, enamel, and dentin caries ranged from 0.57 to 0.99 and were similar for both methods in the different categories. NIRT-HDRI had a higher sensitivity for sound surfaces and enamel caries, as well as a higher specificity for dentin caries. Regarding the obtained images, HDRI allowed for the detection of caries within a greater range of luminance levels, resulting in a more detailed visualization of structures without under- or overexposure. However, HDRI this did not improve the diagnostics significantly. Distinguishing between a processed demineralized enamel and dentin lesions appears to be a problem specific to NIRT and cannot be balanced using HDRI.

  5. Acceptance testing and commissioning of a new model HDR afterloader

    International Nuclear Information System (INIS)

    McDermott, Patrick N.; Somnay, Archana R.; Alecu, Rodica

    1996-01-01

    We have recently performed acceptance testing procedures and have commissioned a new model HDR afterloader, the Varian VariSource with ''Intelligent Drive.'' Our site was one of the first installations worldwide. It is our intent to describe our tests and the results of the tests particularly as they may differ from other afterloaders. The Ir-192 source is unique among afterloaders marketed in the US in that it is very slender (OD of source wire is 0.59 mm) and relatively long (two 0.5 cm sources for a total active length of 1.0 cm). A check of source homogeneity by autoradiograph as urged by the US Nuclear Regulatory Commission demonstrates no detectable source inhomogeneity. Reentrant well ionization chambers are calibrated in the US with a 3.5 mm long source at Accredited Dosimetry Calibration Laboratories. Therefore calibration needs to be considered with some care. Calibration of the first delivered source with a well ionization chamber indicated agreement with the manufacturer's stated activity to within 0.5%. Source positioning is checked with a device called a 'cam scale'. Tests have been carried out on this system and it has been found to accurately indicate source position to within ±0.5 mm. Timer accuracy has been found to be better than 0.1% for dwell times of several hundred seconds. The intelligent drive system and the small source diameter allow the source wire to negotiate paths with small radius of curvature. A series of tests have been made in which the source is forced to negotiate 'U' turns of decreasing radius of curvature. A 4.7 F, 100 cm long catheter was used for these tests and the 'U' turn was positioned at approximately 90 cm. Under these conditions, the VariSource was consistently able to traverse a 1.25 cm radius of curvature, which is better than the manufacturer's stated limit of 1.5 cm

  6. WE-G-BRC-02: Risk Assessment for HDR Brachytherapy

    International Nuclear Information System (INIS)

    Mayadev, J.

    2016-01-01

    Failure Mode and Effects Analysis (FMEA) originated as an industrial engineering technique used for risk management and safety improvement of complex processes. In the context of radiotherapy, the AAPM Task Group 100 advocates FMEA as the framework of choice for establishing clinical quality management protocols. However, there is concern that widespread adoption of FMEA in radiation oncology will be hampered by the perception that implementation of the tool will have a steep learning curve, be extremely time consuming and labor intensive, and require additional resources. To overcome these preconceptions and facilitate the introduction of the tool into clinical practice, the medical physics community must be educated in the use of this tool and the ease in which it can be implemented. Organizations with experience in FMEA should share their knowledge with others in order to increase the implementation, effectiveness and productivity of the tool. This session will include a brief, general introduction to FMEA followed by a focus on practical aspects of implementing FMEA for specific clinical procedures including HDR brachytherapy, physics plan review and radiosurgery. A description of common equipment and devices used in these procedures and how to characterize new devices for safe use in patient treatments will be presented. This will be followed by a discussion of how to customize FMEA techniques and templates to one’s own clinic. Finally, cases of common failure modes for specific procedures (described previously) will be shown and recommended intervention methodologies and outcomes reviewed. Learning Objectives: Understand the general concept of failure mode and effect analysis Learn how to characterize new equipment for safety Be able to identify potential failure modes for specific procedures and learn mitigation techniques Be able to customize FMEA examples and templates for use in any clinic

  7. Paradigmas en progressie in die teologie: *n Perspektief op die ...

    African Journals Online (AJOL)

    Die metodologie as besinningsterrein word egter al belangriker. Gedurende die tweede week van April 1988 het teoloë van dwarsoor Suid-. Afrika by die nuwe gebou van die Raad vir Geesteswetenskaplike Navorsing in. Pretoria byeen gekom vir 'n kongres van amper drie dae met die tema Paradigma.'> 476. ISSN 0259 ...

  8. die korrelasie tussen die gemiddelde daaglikse toename van ...

    African Journals Online (AJOL)

    'n Regressielyn is uit die gegewens bereken deur 'n beswaarde regressieanaliese en die 80 persent-voorspellings- bande is bepaal. Die punte wat ver buite die normale ver- spreidingsband geval hetkon almal met goeie rede as abnor- maal beskou word (sien tabel 1) en is nie ingesluit by die statistiese berekenings nie.

  9. amp' van die ouderling in die Nuwe Testament

    African Journals Online (AJOL)

    Jesus self het geen kerk gestig nie en daarom, veral omdat die Jesus-beweging inter mums ten opsigte van die Joodse godsdiens van sy tyd tot stand gekom het, het ...... Die klem val dus nie op die npoTCTT0fievo<; se rang of outoriteit nie, maar op sy pastorale funksie in die huishouding of huisgemeente (kyk Reicke.

  10. Quality assurance of HDR prostate plans: program implementation at a community hospital.

    Science.gov (United States)

    Rush, Jennifer B; Thomas, Michael D

    2005-01-01

    Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department's planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%.

  11. Quality assurance of HDR prostate plans: Program implementation at a community hospital

    International Nuclear Information System (INIS)

    Rush, Jennifer B.; Thomas, Michael D.

    2005-01-01

    Adenocarcinoma of the prostate is currently the most commonly diagnosed cancer in men in the United States, and the second leading cause of cancer mortality. The utilization of radiation therapy is regarded as the definitive local therapy of choice for intermediate- and high-risk disease, in which there is increased risk for extracapsular extension, seminal vesicle invasion, or regional node involvement. High-dose-rate (HDR) brachytherapy is a logical treatment modality to deliver the boost dose to an external beam radiation therapy (EBRT) treatment to increase local control rates. From a treatment perspective, the utilization of a complicated treatment delivery system, the compressed time frame in which the procedure is performed, and the small number of large dose fractions make the implementation of a comprehensive quality assurance (QA) program imperative. One aspect of this program is the QA of the HDR treatment plan. Review of regulatory and medical physics professional publications shows that substantial general guidance is available. We provide some insight to the implementation of an HDR prostate plan program at a community hospital. One aspect addressed is the utilization of the low-dose-rate (LDR) planning system and the use of existing ultrasound image sets to familiarize the radiation therapy team with respect to acceptable HDR implant geometries. Additionally, the use of the LDR treatment planning system provided a means to prospectively determine the relationship between the treated isodose volume and the product of activity and time for the department's planning protocol prior to the first HDR implant. For the first 12 HDR prostate implants, the root-mean-square (RMS) deviation was 3.05% between the predicted product of activity and time vs. the actual plan values. Retrospective re-evaluation of the actual implant data reduced the RMS deviation to 2.36%

  12. SU-D-19A-07: Dosimetric Comparison of HDR Plesiotherapy and Electron Beam Therapy for Superficial Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A; Jacob, D; Andreou, K; Raben, A; Chen, H; Koprowski, C; Mourtada, F [Christiana Care Hospital, Newark, DE (United States)

    2014-06-01

    Purpose: Large superficial (skin, soft tissue sarcoma) lesions located on curved areas are hard to treat with electrons. The Freiburg Flap (Nucletron, Netherlands) is a flexible mesh style surface which can be easily shaped to fit curved surfaces for reproducible HDR fraction delivery. To understand the fundamental dosimetric differences, a dosimetric comparison was made between HDR plesiotherapy (Freiburg applicator for lesions over 4cm) and external electron beam radiotherapy over cases with varying target curvature (both stylized and clinical cases). Methods: Four stylized cases with variable complexity were created using artificial DICOM axial CT slices and RT structures (a square and three curved structures on a 4.5cm radius cylinder). They were planned using Oncentra v4.3 and exported to Pinnacle v9.6 for electrons planning. The HDR source dwell positions were optimized for the best coverage of the targets using graphical optimization. Electron treatment plans were created in Pinnacle using the same CT and RT structures of three HDR cases with surface lesions previously treated with the Freiburg flap. The En face electron plans used 6-12 MeV electrons and 0.5–1 cm bolus was added to increase surface dose. The electron plans were prescribed to an isodose line to conform to the target. Results: For all lesions, the average target dose coverage was similar (D90ave of 100% for HDR vs 101% for electrons). For lesions with high curvature, the HDR coverage was better (D90 102% vs D90 97% for electron). For all cases, adjacent structures high dose region was lower for HDR than electrons (D1cc 100% for HDR vs D1cc 111% for electrons). Conclusion: HDR plesiotherapy offers excellent target conformity for superficial targets similar to electrons. However, for lesions with complex curved surfaces, HDR has the advantage to achieve better dose distributions using graphical optimization to spare adjacent normal tissue while maximizing target coverage.

  13. Time to PSA rise differentiates the PSA bounce after HDR and LDR brachytherapy of prostate cancer.

    Science.gov (United States)

    Burchardt, Wojciech; Skowronek, Janusz

    2018-02-01

    To investigate the differences in prostate-specific antigen (PSA) bounce (PB) after high-dose-rate (HDR-BT) or low-dose-rate (LDR-BT) brachytherapy alone in prostate cancer patients. Ninety-four patients with localized prostate cancer (T1-T2cN0), age ranged 50-81 years, were treated with brachytherapy alone between 2008 and 2010. Patients were diagnosed with adenocarcinoma, Gleason score ≤ 7. The LDR-BT total dose was 144-145 Gy, in HDR-BT - 3 fractions of 10.5 or 15 Gy. The initial PSA level (iPSA) was assessed before treatment, then PSA was rated every 3 months over the first 2 years, and every 6 months during the next 3 years. Median follow-up was 3.0 years. Mean iPSA was 7.8 ng/ml. In 58 cases, PSA decreased gradually without PB or biochemical failure (BF). In 24% of patients, PB was observed. In 23 cases (24%), PB was observed using 0.2 ng/ml definition; in 10 cases (11%), BF was diagnosed using nadir + 2 ng/ml definition. The HDR-BT and LDR-BT techniques were not associated with higher level of PB (26 vs. 22%, p = 0.497). Time to the first PSA rise finished with PB was significantly shorter after HDR-BT then after LDR-BT (median, 10.5 vs. 18.0 months) during follow-up. Predictors for PB were observed only after HDR-BT. Androgen deprivation therapy (ADT) and higher Gleason score decreased the risk of PB (HR = 0.11, p = 0.03; HR = 0.51, p = 0.01). The higher PSA nadir and longer time to PSA nadir increased the risk of PB (HR 3.46, p = 0.02; HR 1.04, p = 0.04). There was no predictors for PB after LDR-BT. HDR-BT and LDR-BT for low and intermediate risk prostate cancer had similar PB rate. The PB occurred earlier after HDR-BT than after LDR-BT. ADT and higher Gleason score decreased, and higher PSA nadir and longer time to PSA nadir increased the risk of PB after HDR-BT.

  14. A rectum shield for the circular applicator system of a selectron unit (HDR and LDR afterloading)

    International Nuclear Information System (INIS)

    Hetzel, H.; McCoy, M.; Kamleitner, H.; Frommhold, H.

    1987-01-01

    In order to decrease the morbidity rate after combined radiotherapy of the cervix carcinoma, a tungsten shield 3 and 5 mm thick for the rectum has been developed by the authors which is applied with the ring and pin applicator of the selectron unit (LDR and HDR afterloading). The isodose curves were measured in a plexiglas phantom, and the radiation dose at the reference points was determined by means of a ionization dosemeter. The phantom measurements were performed with the same arrangement of sources as applied in radiotherapy. The measurements showed a dose reduction at point Rmax of 33% (HDR) and 44% (LDR) with the tungsten shield 5 mm thick. (orig.) [de

  15. Die toekoms en ons roeping

    Directory of Open Access Journals (Sweden)

    S. du Toit

    1954-03-01

    Full Text Available Om te weet wat ons roeping in die toekoms sal wees, moet ons eers besef wat in ons eie tyd aan die gang is en langs watter lyne die dinge beweeg. Dit is ons plig om te let op die tekens van die tye in die lig van die profetiese Woord. En dan wil ons dadelik beklemtoon dat ons in Suid-Afrika nie in die waan moet lewe dat ons hier onbekommerd en onaangetas deur die wêreldgebeure ons roeping en bestemming kan uitwerk nie.

  16. Die Hervormde Teologiese Studies na vyftig jaar

    African Journals Online (AJOL)

    INLEIDEND. In die tweede helfte van die jaar 1943 het die Hervormde Teologiese Studies die eerste maal verskyn. Dit was die produk van lang besinning en beplanning. Die dryfkrag agter die totstandkoming was prof dr S P Engeibrecht, 'n man wie se idealisme en toewyding aan die kerk groot dinge vir die kerk en ook die ...

  17. Ten years experience in organ preservation using HDR brachytherapy boost for nodal negative, locally advanced prostate cancer

    International Nuclear Information System (INIS)

    Kovacs, G.; Wirth, B.; Bertermann, H.; Galalae, R.; Kohr, P.; Wilhelm, R.; Kimmig, B.

    1996-01-01

    Objectives: In 1986 Bertermann and Brix established the combined external beam (EBT) and HDR brachytherapy (BT) boost treatment for localized prostate cancer. The aim of this analysis is to judge the results of this method after 10 years experience. Material and methods: The treatment and follow-up data of 158 histologically proven, localized (N- by imaging) prostate cancer patients were analyzed. Tumor stages (using transrectal ultrasound/TRUS/) ranged from A2 (T1b) in two, to B (T2) in 105 and C (T3) in 51 cases. Tumor grading: 21 highly differentiated (G1), 79 moderately differentiated (G2) as well as 52 poorly differentiated (G3) and one undifferentiated (G4) tumor. Forty-four patients (pts) had previous surgery on the bladder neck. Forty-eight pts had transitory androgen deprivation or antiandrogen treatment prior to radiation, which lasted for a max. of 6 months and was finished before radiation. Initial PSA was known in 126 cases. In 13% values under 4 ng/ml (Hybritech), as well as 46% not above 20 ng/ml and 40 % above 20 ng/ml, respectively. Ultrasound guided conformal BT treatment planning was carried out. The 2x 15 Gy HDR-BT boost was integrated into the EBT schedule, the total dose was 50 Gy for subclinical disease and 70 Gy for the prostate in 6-7 weeks. Regular follow-up by clinical examination, TRUS + volumetry, PSA, bone scan and after 12 months biopsy. Median follow-up 55 months (6-144 months). Results: Eight of 158 pts died of prostate cancer, 15 of intercurrent disease. Clinical progression in 18 cases (12 systemic, 5 local, 1 both syst. + local). All cases of clinical progression with PSA elevation. All pts, whose PSA did not decrease under 1 ng/ml developed progression (p<0.001). Progression developed in 11% of the 107 organ-confined (T1-2 or A2-B) and 7 (14%) of the advanced tumors (T3 or C). The relation between tumor grading and total progression (clinical + PSA) was as follows: four out of 26 G1 tumors, 9 out of 79 G2 tumors and 21 of the 53

  18. Die owerheidsinmenging met betrekking tot kerklike tughandelinge.

    Directory of Open Access Journals (Sweden)

    L. Roeleveld

    1982-06-01

    Full Text Available Volgens art 29 NGB is die merktekens van die ware kerk die suiwere prediking van die Evangelie, die suiwere bediening van die Sakramente en die gebruik van die kerklike tug. Art. 32 NGB spreek uit dat die Kerkorde nie mag afwyk van wat Christus ingestel het nie. Menslike vindinge en wette om die gewetens te bind en te dwing, moet daarom verwerp word. Die ekskommunikasie of die ban moet toegepas word volgens die Woord van God.

  19. Pentateugtradisies in die boek Hosea

    African Journals Online (AJOL)

    om te bepaal of die verwysing na 'n gebeure te doen het met die verre verlede of met die .... Hosea 2:1-2 JHWH se trou aan sy beloftes. ... dat huile na Egipte sal terugkeer. Die presiese bedoeiing van die woorde 'huile sal terugkeer na Egipte' is omstre- de. Kommentatore soos Rudolph meen dat dit verstaan moet word as ...

  20. Die begrafnisdíens

    African Journals Online (AJOL)

    (De Vaux 1961:108). Was die begrafnis 'n familie of 'n kerklike aangeleentheid? Hierdie vraag word nie in die Bybel beantwoord nie. Abraham het sy vrou begrawe (Gen 23: 19-. 20). Isak en Ismael ..... ver gekom om die begrafnis 'n kerklike aangeleentheid te maak nie. Hierdie stap .... trou aan die sorg van God. * Die kerk ...

  1. Metodes in die Christelike etiek

    African Journals Online (AJOL)

    The basic question in Christian ethics is not primarily. 'What should I do?' The basic question is rather ' ... should therefore be accepted as being part of the method used in Christian ethics. 1. INLEIDEND ..... aan die kant van die onderdrukte' verkondig word, word die Christen opgeroep om horn te skaar aan die kant van die ...

  2. Management of a HDR brachytherapy system in the Hospital Juarez of Mexico; Gestion de un sistema de braquiterapia HDR een el Hospital Juarez de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Serrano F, A.G.; Ramirez R, G.; Gil G, R. [Hospital Juarez de Mexico, Av. l.P.N. 5160, Col. Magdalena de las Salinas, 07760 Mexico D.F. (Mexico); Azorin N, J. [UAM-I, 09340 Mexico D.F. (Mexico); Rivera M, T. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria del IPN, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico)

    2007-07-01

    Full text: In the Hospital Juarez of Mexico, it is carried out a project to implement a Brachytherapy system with high dose rate (HDR) through a Management quality program. In our work center this treatment modality in patients with cervicouterine cancer is used (CaCu), and constantly it is necessary to carry out improvements in the procedures, with the purpose of optimizing them and in consequence to complete the principles of the Radiological Protection, guaranteeing this way, an attention with the quality and safety, such that allow to diminish the risks to the patients and to assure that the received dose in critical organs it finds inside the permitted therapeutic limits, without commit the radiosensitive response of healthy organs. In this work an analysis of the implementation of this system is presented, detailing the procedures so much in the technological infrastructure like human and indicating the necessary technical and operative requirements to reach an adequate practice in HDR brachytherapy. (Author)

  3. Die teologiese skool in die P.U.K vir C.H.O.: met die betekenis van die teologiese skool vir die Christelike wetenskap

    Directory of Open Access Journals (Sweden)

    F. Postma

    1944-03-01

    Full Text Available Die Teologiese Skool van die Gereformeerde Kerk gedink op 29 November 1944 sy vyf-en-sewentigjarige bestaan.Die Raad en Senaat van die P.U.K. vir C.H.O. wil ook langs hierdie weg die Teologiese Skool van harte gelukwens en die versekering gee dat daar by die outoriteite van die P.U.K. ’n diepgevoelde dankbaarheid heers dat hierdie inrigting sovele jare deur onse God en Vader gedra en gespaar is.

  4. Die Frage nach Gerechtigkeit.

    Directory of Open Access Journals (Sweden)

    Martin Jäggle

    2014-07-01

    Full Text Available ENGLISH: In the first part six stages in the author’s path of life are described, which have influenced his engagement with justice. The second part gives an insight into his religious educational work, in which the issue of justice was especially significant on the example of ‘religion in the context of migration’ and of the ecumenic initiative ‘lebens.werte.schule’ (school worth living. The vision of the Kingdom of God and the necessity of participation become apparent. DEUTSCH: Im ersten Teil werden sechs Stationen am Lebensweg des Autors beschrieben, die seine Auseinandersetzung mit Gerechtigkeit geprägt haben. Der zweite Teil gibt Einblick in seine religionspädagogische Arbeit, in der die Frage nach Gerechtigkeit besonders bedeutsam war am Beispiel ‚Religion im Kontext Migration‘ und der ökumenischen Initiative ‚lebens.werte.schule‘. Die Vision vom Reich Gottes und die Notwendigkeit von Partizipation werden dabei deutlich.

  5. Die EG-Kabotageverordnung

    OpenAIRE

    Basedow, Jürgen

    1990-01-01

    Die EG-Kabotageverordnung : e. Schritt zur Verwirklichung d. Dienstleistungsfreiheit im Straßengüterverkehr / Jürgen Basedow ; Ansgar Held. - In: Europäische Zeitschrift für Wirtschaftsrecht. 1. 1990. S. 305-308

  6. Die Bibliothek des Bezirksmuseums Josefstadt

    Directory of Open Access Journals (Sweden)

    Maria Ettl

    2015-01-01

    Josefstadt in Wien werden die Herkunft der Bibliotheksbestände und die beengte Raumsituation beschrieben. Abschließend wird auf die Erfassung der Medien mittels der Bibliothekssoftware „Biblioweb“ eingegangen.

  7. Die verband tussen die sielkundige kontrak en organisasieverbondenheid

    Directory of Open Access Journals (Sweden)

    K. J. Stanz

    1999-06-01

    Full Text Available The relationship between the psychological contract and organisational commitment. The aim of this study is to design a measuring instrument with acceptable metric characteristics for the strength of the psychological contract within the South African context, and to determine empirically the relation between the strength of the psychological contract and organisational commitment. The Dhammanungune Model served as foundation for the design of the Strength of the Psychological Contract Questionnaire which consists of two scales namely, a needs expectation scale and a needs fulfilment expectation scale. The items of each scale have been formulated in the manner that ensures that the respondent reacts consecutively to two instructions namely, (a the level of the expectation and (b the importance of the expectation. This questionnaire was administered together with the Organisational Commitment Questionnaire to two population groups within the military environment. The Pearson Product Moment Correlation was calculated between the strength of the psychological contract and organisational commitment and the significance of the correlations was evaluated. Opsomming Die doel van die studie is om 'n meetinstrument met aanvaarbare metriese eienskappe vir die sterkte van die sielkundige kontrak vir Suid-Afrikaanse omstandighede te ontwerp en om empirics die verband tussen die sterkte van die sielkundige kontrak en organisasieverbondenheid te bepaal. Die sterkte van die sielkundige kontrak vraelys is op grond van die Dhammanungune-model ontwerp en het uit twee skale naamlik, die behoefteverwagting- en vervullingsverwagtingskale bestaan. Items vir eike skaal is sodanig geformuleer dat die respondent agteropeenvolgens op twee instruksies naamlik (a die vlak van die verwagting en (b die belangrikheid van die verwagting moet reageer. Die vraelys is saam met die organisasieverbondenheidsvraelys op twee populasies uit 'n militere omgewing toegepas. Die Pearson

  8. Emergency rescue in accidents with HDR afterloading units

    International Nuclear Information System (INIS)

    Kaulich, T.W.; Nuesslin, F.; Becker, G.; Lamprecht, U.; Bamberg, M.

    1999-01-01

    Problem: HDR brachyradiotherapy has minimized the exposure to radiation of the personnel working in this field. Nonetheless there are periodically reported troubles with afterloading units concerning the retraction of sources that require immediate action for the limitation of possible damage. Legal Principles according to the German Regulation Concerning Protection against Radiation (Strahlenschutzverordnung=StrlSchV): If in afterloading brachyradiotherapy the radiation source remains extended through malfunction we deal with an emergency according to the StrlSchV. The rescue personnel should be chosen in accordance with Paragraph 50 StrlSchV. Organization of the Rescue of the Patient: The quickest possible rescue of a patient in an emergency demands an unequivocal definition of responsibilities. Our recommendations in this instance: The physicist is responsible for the organization of the emergency rescue. The radiation oncologist in charge informs himself about the necessary emergency measures before starting the treatment and carries out the emergency rescue. If the physicist diagnoses a failure in the retraction of the source he tries to remove the failure. If he doesn't succeed in retracting the source the radiation oncologist carries out the rescue of the patient. The organizational structure of the clinic allowing, the emergency physician should invariably be the physician who placed the applicator. In the emergency rescue the radiation oncologist should be protected by a lead barrier and use manipulators. Dose Assessment in Personnel and Patient: The radiation exposure of the rescue personnel is calculated from the photon-equivalence dose H x with the help of the dose-rate constant of 192 Ir. According to the same procedure there can be evaluated the local radiation exposure of the patient concerned. Conclusions: Generally speaking, all considerations regarding the topic of emergency rescue should always start out from a worst-case scenario. Of all the

  9. Die postpolitische Stadt

    Directory of Open Access Journals (Sweden)

    Erik Swyngedouw

    2013-12-01

    Full Text Available Die Polis ist tot, es lebe die kreative Stadt! Während die Stadt, zumindest in Teilen des städtischen Raums, blüht und gedeiht, scheint die Polis im idealisierten griechischen Sinn dem Untergang geweiht; in diesem Verständnis ist sie der Ort der öffentlichen politischen Auseinandersetzung und demokratischen Unterhandlung und somit eine Stätte (oft radikaler Abweichung und Unstimmigkeit, an der die politische Subjektivierung buchstäblich ihren Platz hat. Diese Figur einer entpolitisierten (oder postpolitischen und postdemokratischen Stadt im Spätkapitalismus bildet das Leitmotiv des vorliegenden Beitrags. Ich lehne mich dabei an Jacques Rancière, Slavoj Žižek, Chantal Mouffe, Mustafa Dikeç, Alain Badiou und andere Kritiker jenes zynischen Radikalismus an, der dafür gesorgt hat, dass eine kritische Theorie und eine radikale politische Praxis ohnmächtig und unfruchtbar vor jenen entpolitisierenden Gesten stehen, die in der polizeilichen Ordnung des zeitgenössischen neoliberalen Spätkapitalismus als Stadtentwicklungspolitik [urban policy] und städtische Politik [urban politics] gelten. Ziel meiner Intervention ist es, das Politische wieder in den Mittelpunkt der zeitgenössischen Debatten über das Urbane zu stellen. [...

  10. Determinación de la distribución de dosis en tratamientos de cáncer de mama con fuentes de 192 Ir HDR / Determination of doses distributions on breast cancer treatments with 192 Ir HDR sources

    OpenAIRE

    Beltrán Gómez, Cristian Camilo

    2010-01-01

    La Braquiterapia de alta tasa de dosis HDR es una moderna técnica de tratamiento que ha venido teniendo un rápido crecimiento en su uso clínico, reemplazando a la braquiterapia de baja tasa de dosis LDR. La braquiterapia HDR se caracteriza por utilizar fuentes radiactivas con tasas de dosis mayores a 12 Gy/h, por tanto con propósitos de protección radiológica debe ser realizada con equipos de carga remota, es común en los tratamientos de braquiterapia HDR depositar altas dosis por fracción, c...

  11. Presumed atypical HDR syndrome associated with Band Keratopathy and pigmentary retinopathy.

    Science.gov (United States)

    Kim, Cinoo; Cheong, Hae Il; Kim, Jeong Hun; Yu, Young Suk; Kwon, Ji Won

    2011-01-01

    This report describes presumed atypical hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome associated with unexpected ocular findings. The patient had exotropia, bilateral band keratopathy, and pigmentary retinopathy, including attenuated retinal vessels and atrophy of the retinal pigment epithelium. Even though the calcific plaques were successfully removed, visual acuity in both eyes gradually decreased and electroretinography was extinguished. Copyright 2009, SLACK Incorporated.

  12. A gEUD-based inverse planning technique for HDR prostate brachytherapy: Feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Giantsoudi, D. [Department of Radiological Sciences, University of Texas Health Sciences Center, San Antonio, Texas 78229 (United States); Department of Radiation Oncology, Francis H. Burr Proton Therapy Center, Boston, Massachusetts 02114 (United States); Baltas, D. [Department of Medical Physics and Engineering, Strahlenklinik, Klinikum Offenbach GmbH, 63069 Offenbach (Germany); Nuclear and Particle Physics Section, Physics Department, University of Athens, 15701 Athens (Greece); Karabis, A. [Pi-Medical Ltd., Athens 10676 (Greece); Mavroidis, P. [Department of Radiological Sciences, University of Texas Health Sciences Center, San Antonio, Texas 78299 and Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, 17176 (Sweden); Zamboglou, N.; Tselis, N. [Strahlenklinik, Klinikum Offenbach GmbH, 63069 Offenbach (Germany); Shi, C. [St. Vincent' s Medical Center, 2800 Main Street, Bridgeport, Connecticut 06606 (United States); Papanikolaou, N. [Department of Radiological Sciences, University of Texas Health Sciences Center, San Antonio, Texas 78299 (United States)

    2013-04-15

    Purpose: The purpose of this work was to study the feasibility of a new inverse planning technique based on the generalized equivalent uniform dose for image-guided high dose rate (HDR) prostate cancer brachytherapy in comparison to conventional dose-volume based optimization. Methods: The quality of 12 clinical HDR brachytherapy implants for prostate utilizing HIPO (Hybrid Inverse Planning Optimization) is compared with alternative plans, which were produced through inverse planning using the generalized equivalent uniform dose (gEUD). All the common dose-volume indices for the prostate and the organs at risk were considered together with radiobiological measures. The clinical effectiveness of the different dose distributions was investigated by comparing dose volume histogram and gEUD evaluators. Results: Our results demonstrate the feasibility of gEUD-based inverse planning in HDR brachytherapy implants for prostate. A statistically significant decrease in D{sub 10} or/and final gEUD values for the organs at risk (urethra, bladder, and rectum) was found while improving dose homogeneity or dose conformity of the target volume. Conclusions: Following the promising results of gEUD-based optimization in intensity modulated radiation therapy treatment optimization, as reported in the literature, the implementation of a similar model in HDR brachytherapy treatment plan optimization is suggested by this study. The potential of improved sparing of organs at risk was shown for various gEUD-based optimization parameter protocols, which indicates the ability of this method to adapt to the user's preferences.

  13. Determination of the dose of traffic in HDR brachytherapy with ALANINE/R PE technique

    International Nuclear Information System (INIS)

    Guzman Calcina, C. S.; Chen, F.; Almeida, A. de; Baffa, O.

    2001-01-01

    It determines, experimentally, the dose of traffic in brachytherapy for High Dose Rate (HDR), using for the first-time the Electronic Paramagnetic Resonance (EPR) technique with alanine detectors. The value obtained is the published next to obtained using lithium fluoride thermoluminescent dosimeters [es

  14. Prediction of HDR quality by combining perceptually transformed display measurements with machine learning

    Science.gov (United States)

    Choudhury, Anustup; Farrell, Suzanne; Atkins, Robin; Daly, Scott

    2017-09-01

    We present an approach to predict overall HDR display quality as a function of key HDR display parameters. We first performed subjective experiments on a high quality HDR display that explored five key HDR display parameters: maximum luminance, minimum luminance, color gamut, bit-depth and local contrast. Subjects rated overall quality for different combinations of these display parameters. We explored two models | a physical model solely based on physically measured display characteristics and a perceptual model that transforms physical parameters using human vision system models. For the perceptual model, we use a family of metrics based on a recently published color volume model (ICT-CP), which consists of the PQ luminance non-linearity (ST2084) and LMS-based opponent color, as well as an estimate of the display point spread function. To predict overall visual quality, we apply linear regression and machine learning techniques such as Multilayer Perceptron, RBF and SVM networks. We use RMSE and Pearson/Spearman correlation coefficients to quantify performance. We found that the perceptual model is better at predicting subjective quality than the physical model and that SVM is better at prediction than linear regression. The significance and contribution of each display parameter was investigated. In addition, we found that combined parameters such as contrast do not improve prediction. Traditional perceptual models were also evaluated and we found that models based on the PQ non-linearity performed better.

  15. Comparing subjective and objective quality assessment of HDR images compressed with JPEG-XT

    DEFF Research Database (Denmark)

    Mantel, Claire; Ferchiu, Stefan Catalin; Forchhammer, Søren

    2014-01-01

    In this paper a subjective test in which participants evaluate the quality of JPEG-XT compressed HDR images is presented. Results show that for the selected test images and display, the subjective quality reached its saturation point starting around 3bpp. Objective evaluations are obtained...

  16. Quality assurance of HDR 192Ir sources using a Fricke dosimeter.

    Science.gov (United States)

    Austerlitz, C; Mota, H; Almeida, C E; Allison, R; Sibata, C

    2007-04-01

    A prototype of a Fricke dosimetry system consisting of a 15 x 15 x 15 cm3 water phantom made of Plexiglas and a 11.3-ml Pyrex balloon fitted with a 0.2 cm thick Pyrex sleeve in its center was created to assess source strength and treatment planning algorithms for use in high dose rate (HDR) 192Ir afterloading units. In routine operation, the radioactive source is positioned at the end of a sleeve, which coincides with the center of the spherical balloon that is filled with Fricke solution, so that the solution is nearly isotropically irradiated. The Fricke system was calibrated in terms of source strength against a reference well-type ionization chamber, and in terms of radial dose by means of an existing algorithm from the HDR's treatment planning system. Because the system is based on the Fricke dosimeter itself, for a given type and model of 192Ir source, the system needs initial calibration but no recalibration. The results from measurements made over a 10 month period, including source decay and source substitutions, have shown the feasibility of using such a system for quality control (QC) of HDR afterloading equipment, including both the source activity and treatment planning parameters. The benefit of a large scale production and the use of this device for clinical HDR QC audits via mail are also discussed.

  17. Photometric and Colorimeric Comparison of HDR and Spctrally Resolved Rendering Images

    DEFF Research Database (Denmark)

    Amdemeskel, Mekbib Wubishet; Soreze, Thierry Silvio Claude; Thorseth, Anders

    2017-01-01

    In this paper, we will demonstrate a comparison between measured colorimetric images, and simulated images from a physics based rendering engine. The colorimetric images are high dynamic range (HDR) and taken with a luminance and colour camera mounted on a goniometer. For the comparison, we have ...

  18. Quality control and performance evaluation of microselectron HDR machine over 30 months

    International Nuclear Information System (INIS)

    Balasubramanian, N.; Annex, E.H.; Sunderam, N.; Patel, N.P.; Kaushal, V.

    2008-01-01

    To assess the performance evaluation of Microselectron HDR machine the standard quality control and quality assurance checks were carried out after each loading of new 192 Ir brachytherapy source In the machine. Total 9 loadings were done over a period of 30 months

  19. Implementation of the technique of partial irradiation accelerated the breast with high doses (HDR) brachytherapy

    International Nuclear Information System (INIS)

    Molina Lopez, M. Y.; Pardo Perez, E.; Castro Novais, J.; Martinez Ortega, J.; Ruiz Maqueda, S.; Cerro Penalver, E. del

    2013-01-01

    The objective of this work is presents procedure carried out in our Centre for the implementation of the accelerated partial breast irradiation (APBI, accelerated partial-breast irradiation) with high-rate brachytherapy (HDR), using plastic tubes as applicators. Carried out measures, the evaluation of the dosimetric parameters analyzing and presenting the results. (Author)

  20. HDR brachytherapy in carcinoma of cervix: initial experience at AWARE hospitals

    International Nuclear Information System (INIS)

    Rajendran, M.; Reddy, K.D.; Reddy, R.M.; Reddy, J.M.; Reddy, B.V.N.; Kiran Kumar; Gopi, S.; Dharaniraj; Janardhanan

    2002-01-01

    High dose rate (HDR) brachytherapy is well established in the management of gynaecological malignancies. A report on the initial results of one and half year experience with a consistent dose/fractionation schedule and procedure of planning with delivery of treatment schedule is presented

  1. Mixed integer programming improves comprehensibility and plan quality in inverse optimization of prostate HDR Brachytherapy

    NARCIS (Netherlands)

    Gorissen, B.L.; den Hertog, D.; Hoffmann, A.L.

    2013-01-01

    Current inverse treatment planning methods that optimize both catheter positions and dwell times in prostate HDR brachytherapy use surrogate linear or quadratic objective functions that have no direct interpretation in terms of dose-volume histogram (DVH) criteria, do not result in an optimum or

  2. Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus

    Directory of Open Access Journals (Sweden)

    M. M. Nel

    1990-07-01

    Full Text Available Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus word beskryf. ’n Dun bindweefselkapsel omring die lewer. Die hepatosietrangskikking vertoon as lobules, met die koorde van hepatosiete wat vanaf ’n sentrale vene uitradieer en met mekaar anastomaseer. Indiwiduele lewerlohules vertoon nie duidelike grense nie, maar enkele duidelike triades word wel in die lewer van O. mossambicus aangetref. Die hepatosiete bevat ’n enkele ronde kern met ’n duidelike nukleolus en die growwe endoplasmiese retikula kom in twee of meer rye om die kerne en teen die selgrense van die hepatosiete voor. Die ander sitoplasmiese organelle kom verspreid in die hepatosietsitoplasma voor. Die eksokriene pankreasselle is om die portale venes gesetel. Die kerne van hierdie selle is rond en is hasaal in die kubies- tot silindervormige selle gelee. ’n Goedontwikkelde growwe endoplasmiese retikulum — vesikulêr, tubulêr en sirkulêr in vorm — en sektretoriese granules wat apikaal in die sel gelee is, kom voor.

  3. Die teologiese arbeid van Antonius HJ Gunneweg

    African Journals Online (AJOL)

    En dis 'n klein treetjie van klagte na aanklag en na protes teen die gode, die heersers wat die mens vernietig deur hom oor sy ware lewe te bedrieg. Die ideologie eis dan ook dienooreenkomstig die bevryding en emansipasie van die mens van die gode en van God (1983: 118—119). Volgens die Jahwis is dit die slang wat, ...

  4. Braquiterapia endoluminal HDR no tratamento de tumores primários ou recidivas na árvore traqueobrônquica

    Directory of Open Access Journals (Sweden)

    Maria Fortunato

    2009-03-01

    bronchial recurrence, four patients have died, one after massive haemoptysis and three due to disease progression.Discussion and conclusions: Patients undergoing brachytherapy for symptomatic primary tumours or endobronchial recurrence show good tolerance, important symptom relief and improved quality of life. Despite the small size of our sample, it is clear that EBT with HDR plays an important role in the palliative/curative treatment of these patients.Rev Port Pneumol 2009; XV (2: 151-164 Palavras-chave: Braquiterapia de alta taxa de dose, carcinoma do pulmão, obstrução da árvore traqueobrônquica, Key-words: High dose brachytherapy, lung cancer, tracheobronchial obstruction

  5. Die benutting van vraelyste met die oog op meer effektiewe ...

    African Journals Online (AJOL)

    UPuser

    effektiewe stresbeheer as een van die temas te hanteer. Op grond van die navorsing deur onder andere Lawson (1985) en Taylor (1999) sou ek graag die proses van differensiasie2 ook by genoemde lys voeg as tema vir bespreking tydens huweliksvoorbereiding. 2 Differensiasie kan beskryf word as die losmaakproses ...

  6. die aard van wetgewende diskresies by die suid-afrikaanse ...

    African Journals Online (AJOL)

    Administrator

    In enige moderne demokrasie is daar een of ander vorm van skeiding van magte tussen die wetgewende, uitvoerende en regsprekende gesag. Hierdie skeiding van magte, die sogenaamde trias politica, kan sover teruggevoer word as 1215, met die ondertekening van die Magna Carta deur Koning John van Engeland.

  7. die doeltreffendheid van die afrikaanse woordelys en spelreels

    African Journals Online (AJOL)

    sluiting by die reel vir die verdubbeling van medeklinkers na 'n kort, be- klemtoonde klinker, woorde soos ballet, ballon, terras, terrein, dissipel en dissipline slegs met een konsonant na die eerste vokaal gespel moes word, omdat daardie voorafgaande vokaal onbeklemtoon is. Ook hierdie uit- sondering op die reel word ...

  8. Die aanspraak op Goddelike steun in 'n konfliksituasie volgens die ...

    African Journals Online (AJOL)

    laws, and ethical or political principles. A synchronic investigation of relevant Old ... die toneel gebring met die vraag: 'aan wie se kant is God' (vgl bv The road to. Damascus 1979:6)? Volgens .... betrekking tot die Ou Testament: Hoe moet ons vasstel wie se kant God nou regtig kies, of wie veg aan die kant van God en wie ...

  9. Needle displacement during HDR brachytherapy in the treatment of prostate cancer

    International Nuclear Information System (INIS)

    Damore, Steven J.; Syed, A.M. Nisar; Puthawala, Ajmel A.; Sharma, Anil

    2000-01-01

    Purpose: We used clinical patient data to examine implant displacement between high dose rate (HDR) brachytherapy fractions for prostate cancer to determine its impact on treatment delivery. Materials and Methods: We analyzed the verification films taken prior to each fraction for 96 consecutive patients treated with HDR brachytherapy boosts as part of their radiation therapy for definitive treatment of organ-confined prostate cancer at our institution. Patients were treated with 18-24 Gy in 4 fractions of HDR delivered in 40 hours followed by 36-39.6 Gy external beam radiation to the prostate. We determined the mean and maximum displacement distances of marker seeds placed in the prostate and of the implanted needles between HDR fractions. Results: Mean and maximum displacement distances between fractions were documented up to 7.6 mm and 28.5 mm, respectively, for the implant needles and 3.6 mm and 11.4 mm, respectively, for the gold marker seeds. All displacement of implant needles occurred in the caudal direction. At least 1 cm caudal displacement of needles occurred prior to 15.5% all fractions. Manual adjustment of needles was required prior to 15% of fractions, and adjustment of the CLP only was required in 24%. Most of the displacement for both the marker seeds and needles occurred between the first and second fractions. Conclusions: There is significant caudal displacement of interstitial implant needles between HDR fractions in our prostate cancer patients. Obtaining verification films and making adjustments in the treatment volume prior to each fraction is necessary to avoid significant inaccuracies in treatment delivery

  10. SU-E-T-574: Fessiblity of Using the Calypso System for HDR Interstitial Catheter Reconstruction

    International Nuclear Information System (INIS)

    Li, J S; Ma, C

    2014-01-01

    Purpose: It is always a challenge to reconstruct the interstitial catheter for high dose rate (HDR) brachytherapy on patient CT or MR images. This work aims to investigate the feasibility of using the Calypso system (Varian Medical, CA) for HDR catheter reconstruction utilizing its accuracy on tracking the electromagnetic transponder location. Methods: Experiment was done with a phantom that has a HDR interstitial catheter embedded inside. CT scan with a slice thickness of 1.25 mm was taken for this phantom with two Calypso beacon transponders in the catheter. The two transponders were connected with a wire. The Calypso system was used to record the beacon transponders’ location in real time when they were gently pulled out with the wire. The initial locations of the beacon transponders were used for registration with the CT image and the detected transponder locations were used for the catheter path reconstruction. The reconstructed catheter path was validated on the CT image. Results: The HDR interstitial catheter was successfully reconstructed based on the transponders’ coordinates recorded by the Calypso system in real time when the transponders were pulled in the catheter. After registration with the CT image, the shape and location of the reconstructed catheter are evaluated against the CT image and the result shows an accuracy of 2 mm anywhere in the Calypso detectable region which is within a 10 cm X 10 cm X 10 cm cubic box for the current system. Conclusion: It is feasible to use the Calypso system for HDR interstitial catheter reconstruction. The obstacle for its clinical usage is the size of the beacon transponder whose diameter is bigger than most of the interstitial catheters used in clinic. Developing smaller transponders and supporting software and hardware for this application is necessary before it can be adopted for clinical use

  11. Effectiveness of two different HDR brachytherapy regimens with the same BED value in cervical cancer

    Directory of Open Access Journals (Sweden)

    Rajesh Vashistha

    2010-07-01

    Full Text Available Purpose: To analyze the effectiveness of biologically effective dose (BED in two different regimens of HDR brachytherapy keeping the same total BED to point A and to compare the relationship of overall treatment time in terms of local control and bladder and rectal complications.Material and methods: The study included two groups comprising a total of 90 cervical cancer patients who underwent external beam radiotherapy (EBRT followed by HDR intracavitary brachytherapy (ICBT. EBRT treatment was delivered by a Co-60 teletherapy unit to a prescribed dose of 45 Gy with 1.8 Gy per fraction in 25 fractions over a period of five weeks. Parallel opposed anterior–posterior (AP/PA fields with no central shielding were used, followed by the HDR ICBT dose, to point A, of either two fractions of 9.5 Gy with a gap of 10 days, or three fractions of 7.5 Gy with a gap of 7 days between the fractions. Gemcitabine (dose of 150 mg/m2 was given weekly to all the patients as a radiosensitizer. The calculate BED3 to point A was almost the same in both groups to keep the same late complication rates. The doses, and BED10 and BED3, were calculated at different bladder and rectal point as well as at the lymphatictrapezoid points. During and after treatment patients were evaluated for local control and complications for 24 months.Results and Conclusions: Doses and BEDs at different bladder, rectal and lymphatic trapezoid points, local control, and complications in both HDR ICBT groups did not have statistically significant differences (p > 0.05. Both HDR ICBT schedules are well tolerable and equally effective.

  12. Perioperative high dose rate (HDR brachytherapy in unresectable locally advanced pancreatic tumors

    Directory of Open Access Journals (Sweden)

    Brygida Białas

    2011-07-01

    Full Text Available Purpose: The aim of the study was to present an original technique of catheter implantation for perioperative HDR-Ir192 brachytherapy in patients after palliative operations of unresectable locally advanced pancreatic tumors and to estimate the influence of perioperative HDR-Ir192 brachytherapy on pain relief in terminal pancreatic cancer patients. Material and methods: Eight patients with pancreatic tumors located in the head of pancreas underwent palliative operations with the use of HDR-Ir192 brachytherapy. All patients qualified for surgery reported pain of high intensity and had received narcotic painkillers prior to operation. During the last phase of the surgery, the Nucletron® catheters were implanted in patients to prepare them for later perioperative brachytherapy. Since the 6th day after surgery HDR brachytherapy was performed. Before each brachytherapy fraction the location of implants were checked using fluoroscopy. A fractional dose was 5 Gy and a total dose was 20 Gy in the area of radiation. A comparative study of two groups of patients (with and without brachytherapy with stage III pancreatic cancer according to the TNM scale was taken in consideration. Results and Conclusions: The authors claim that the modification of catheter implantation using specially designed cannula, facilitates the process of inserting the catheter into the tumor, shortens the time needed for the procedure, and reduces the risk of complications. Mean survival time was 5.7 months. In the group of performed brachytherapy, the mean survival time was 6.7 months, while in the group of no brachytherapy performed – 4.4 months. In the group of brachytherapy, only one patient increased the dose of painkillers in the last month of his life. Remaining patients took constant doses of medicines. Perioperative HDR-Ir192 brachytherapy could be considered as a practical application of adjuvant therapy for pain relief in patients with an advanced pancreatic cancer.

  13. Die huwelik as identiteitsmerker in die Ou Testament

    African Journals Online (AJOL)

    p1243322

    Gen 2:18). Uit die woorde van Genesis 2:24 dat man en vrou een sal wees, lei die derde formulier af dat dit “getuig dat die huwelik 'n allesinsluitende gemeenskap is ..... die formule gebruik word: “Hier volg die vertelling oor X se nageslag.” (Gen ..... verwys daarna as “intertwining the principal value concepts of tradition”.

  14. Narratiwiteit en die Ou Testament

    African Journals Online (AJOL)

    INLEIDING. Die literêre benadering tot die Ou-Testamentiese narratiewe word algemeen as 'n alternatiewe paradigma in die Bybelwetenskappe aanvaar. Oor die filosofiese uit- gangspunte wat hierdie nuwe paradigma ten grondslag lê, bestaan daar egter nog weinig eenstemmigheid. Heelwat probleme van filosofiese en ...

  15. Eksistensialisme in die Franse letterkunde

    Directory of Open Access Journals (Sweden)

    A. A. Teurlinckx

    1966-03-01

    Full Text Available Nooit sou die Franse jeug — en die van Europa en verder — in dié mate deur die eksistensialisme be'invloed gewees het nie, indien hierdie filosofie in wysgerige traktate sou begrawe gelê het. Die eksistensialiste het die koning van die filosofiese verhaal, Voltaire, met sukses op sy Candide- en Zadig-pad gevolg en hulle teorieë in letterkundige werke, ver- hale, romans en ook toneelstukke kwytgeraak, wat baie gelees is en waaruit ook ander literatore kragte en inspirasie geput het. Omrede daarvan is daar inderdaad baie eksistensialisme in die Franse letterkunde, maar ’n eintlike eksistensialistiese letterkunde was daar nie, en ’n Eksistensialistiese Letterkun­ dige skool het nooit bestaan nie. Ook sit hierdie eksistensialiste nie langs dieselfde vuur nie. Die Christelike eksistensialis Gabriel Marcel het op 21 April van hierdie jaar uitgevaar teen die „Sartriane” na aanleiding van die opvoering van Les Paravents, Die W indskerms van Jean Genêt in ’n Paryse staatsondersteunde teater. „Mens mag seker wees”, skryf Marcel in Les Nouvelles Littéraires, „dat die hele sartriaanse parogie sal skreeu: groot meesterwerk”. Voortgaande op sy distansiëring kan die literêre eksistensialiste in drie groepe ingedeel word: 1. Die Sartriane; 2. Die Christelike Eksistensialiste; 3. Die Onafhanklikes.

  16. Surface dose characterisation of the Varian Ir-192 HDR conical surface applicator set with a vertically orientated source

    Energy Technology Data Exchange (ETDEWEB)

    Buchauer, Konrad; Henke, Guido; Schiefer, Hans; Plasswilm, Ludwig [Kantonsspital St. Gallen, Department of Radiation Oncology, St. Gallen (Switzerland)

    2014-12-15

    etabliertes Mittel um mit Ir-192 HDR-Brachytherapie nichtmelanomatoese Hautkrebserkrankungen mit hohen Tumorkontrollraten zu behandeln. In dieser Arbeit wird eine hochaufloesende Analyse der Oberflaechendosis eines Varian-Varisource-GammaMed+ IX-Afterloader-Konus-Applikatorsatzes des vertikalen Typs dargestellt. Analyse der Oberflaechendosisverteilung des Applikatorsatzes im Hinblick auf Unregelmaessigkeiten, die fuer aehnliche Applikatoren bereits berichtet wurden. Weiterhin wird untersucht, ob Applikatoren des vertikalen Typs zusaetzliche Verfahren als Ergaenzung der aktuell vorgeschlagenen Methoden zur Verifikation des Dosisoutputs von konischen Oberflaechenapplikatoren benoetigen. Die Verifikation der absoluten Dosis wird nach Herstellerangaben durchgefuehrt. Die Dosisverteilung an der Oberflaeche wird zusaetzlich mit Gafchromic-EBT3-Filmdosimetrie bestimmt. Der Begriff ''therapeutische Dosis'' ist in dieser Arbeit mit 85 % der verschriebenen Dosis definiert. Zehn ausgewertete Applikatoren zeigen Unterdosierungen in der Applikatormitte, mit einer mittlere Groesse von 2,0 mm x 3,6 mm (± 0,6 mm), dosimetrisch deutlich unter 85 % der verschriebenen Dosis. Die Unterdosierung liegt 2,2 mm (1,4-2,7 mm) seitlich der Zentralachse und verursacht eine generelle Asymmetrie in der Dosisverteilung. Ein Schiefstand von 8 (± 1 ) wurde fuer die verwendete Quelle bestimmt. Eine um mehr als 15 % reduzierte Dosis in der Applikatormitte wurde bei Oberflaechenapplikatoren bislang nicht berichtet. Quellenschiefstand wurde als Parameter identifiziert, der die Handhabung dieser Oberflaechenapplikatoren und moeglicherweise den Therapieerfolg beeinflussen kann. Das beschriebene kleinraeumige Dosisartefakt kann systematischen Einfluss auf kammerbasierte Dosisverifikationsverfahren haben. Wir empfehlen daher bei der Applikatorkommissionierung eine zusaetzliche Absicherung mit Filmdosimetrie. (orig.)

  17. Assisted Dying in Canada.

    Science.gov (United States)

    Schuklenk, Udo

    This paper makes an affirmative ethical case in favour of the decriminalization of assisted dying in Canada. It then proceeds to defending the affirmative case against various slippery-slope arguments that are typically deployed by opponents of assisted dying. Finally, a recent case of questionable professional conduct by anti-euthanasia campaigners cum academics is flagged as a warning to all of us not to permit the quality of the professional debate to deteriorate unacceptably, despite the personal emotional investments involved on all sides of the debate.

  18. Die afrikaner en sy pers*

    Directory of Open Access Journals (Sweden)

    G. D. Scholtz

    1963-03-01

    Full Text Available Die versoek w at van u inrigting tot my gekom het om buitengewone professor in die Persw etenskap te word, was vir my deels vererend, m aar deels het dit my in 'n moeilike posisie gestel. Dit was vir my vererend, om dat dit gekom het van 'n universiteit m et wie se Christelik- Nasionale koers ek my ten voile kan vereenselwig. Dit was dan ook vir my vererend, om dat ek daardeur in staat gestel kan w ord om die volk w aartoe ek behoort, op 'n vir my nuwe terrein te dien. As sodanig is dit vir my im m ers m oontlik om ook ’n beskeie bydrae te lewer tot die geestelike vorm ing van die jeug van ons volk. Dit het my m oeilik geval om, w aar ek reeds die m iddeljarige leeftyd bereik het, nou vir die eerste maal as dosent op te tree, aangesien ek daarvan in die verlede nie die m inste kennis en ervaring opgedoen het nie. As joernalis rig ek my im m ers tot die breë publiek deur middel van die pen. As dosent m oet ek my deur middel van die mond tot die studente rig. Dit lê voor die hand dat die eise w at so aan my gestel word, totaal anders is as dié waar- aan ek oor 'n tydperk van m eer as 'n kw arteeu as joer­ nalis gewoond geraak het.

  19. Die vestiging van die Kerk in Natal, die Vrystaat en Transvaal na ...

    African Journals Online (AJOL)

    as eerste predikant van die Voortrekkers laat orden en bevestig. Daama het verskeie kerksake van tyd tot tyd aandag geniet. Met betrekking tot die bevestiging van huwelike stel Retief 'n meer ordelike reëling daar, naamlik dat die gebooie van voomemende egpa- re van nou af drie maal in die kerk afgekondig moes wrord ...

  20. Dosimetry experience of 192IR sources used In HDR brachytherapy for cervical cancer

    International Nuclear Information System (INIS)

    Daci, Lulzime; Myrku, Rodina Cela

    2013-01-01

    Purpose/Objective: The 192IR Sources are the most commonly used in radiotherapy treatments HDR worldwide. According to international recommendations on quality assurance in HDR brachytherapy, an acceptance test based on the determination of the source strength of any new source shall be carried out before first application to verify the manufacturer’s calibration data. The present paper gives the experimental determination of the source strength for our brachytherapy sources used until now in brachytherapy treatments. Materials/Methods: At Mother Teresa University Hospital we have a cost-effective gynecological brachytherapy unit from Eckert & Ziegler BEBIG named GyneSource® that is a five channel HDR after loader equipped with an 192IR source. The software used is HDR plus™ 2.5 that delivers an optimized treatment plan and makes the process especially fast and we use intracavitary BEBIG applicators. From April 2009 up to December 2012, we have imported nine HDR 192IR Sources. The exchange of the source and acceptance test is done by the physicist of the clinic once the source is imported. The measurements are done with a Well-type ionization chamber HDR1000 Plus and the electrometer used is MAX4000. Only seven sources are compared as we miss the dosimetry data of the first source, and the forth source was not measured and not used because the machine was not working in that time. Results/Conclusions: Eight sources were accepted for clinically use as the measurement were within the tolerance. The source number four with e deviation of -1.92% has been double checked compared with a free in-air measurement with farmer type chamber that gave a deviation to source certificate of 4% that is still inside the tolerance to accept a source for clinical use. The deviations of measured Air Kerma rate to the value of the sources certificates of all our used 192IR sources are less than 2%, which are within the tolerance. The checked value of updated source strength in

  1. Die skool en die onderwyser as faktore in die geestesgesondheid van die kind*

    Directory of Open Access Journals (Sweden)

    B. C. Schutte

    1961-03-01

    Full Text Available Ons hou geestesgesondheidsweke, stig beroepsentrums, samel geld in om mense wat geestelik siek is te genees, klae oor die tekort aan psigiaters, kliniese sielkundiges, bedryfsielkundiges, voorligters, skoolpsigoloë,ens. ’n Karige kwarteeu gelede het ons aan al hierdie dinge slegs akademiese aandag gewy. In hierdie kursus wordverskeie tipes kinders bespreek en geleer hoe om hulle probleme te benader.

  2. When Somebody Dies

    Science.gov (United States)

    ... bottle became useless. The container is gone, but what's inside — the water — remains. The part of a person that's left after the body dies is often called the "soul" or "spirit." Some people believe the soul is the part ...

  3. Die Kunst des Scheiterns

    DEFF Research Database (Denmark)

    Juul, Jesper

    2014-01-01

    Menschen haben von Kindesbeinen an das Verlangen, Erfolge zu erzielen und Kompetenz zu erreichen. Computerspieler entscheiden sich jedoch fortlaufend für eine Aktivität, die oft und wiederholt zum Verlieren führen muss und ein taubes Gefühl der Unfähigkeit erzeugt. Im Kino, im Theatersaal und bei...

  4. The Oryza sativa Regulator HDR1 Associates with the Kinase OsK4 to Control Photoperiodic Flowering.

    Directory of Open Access Journals (Sweden)

    Xuehui Sun

    2016-03-01

    Full Text Available Rice is a facultative short-day plant (SDP, and the regulatory pathways for flowering time are conserved, but functionally modified, in Arabidopsis and rice. Heading date 1 (Hd1, an ortholog of Arabidopsis CONSTANS (CO, is a key regulator that suppresses flowering under long-day conditions (LDs, but promotes flowering under short-day conditions (SDs by influencing the expression of the florigen gene Heading date 3a (Hd3a. Another key regulator, Early heading date 1 (Ehd1, is an evolutionarily unique gene with no orthologs in Arabidopsis, which acts as a flowering activator under both SD and LD by promoting the rice florigen genes Hd3a and RICE FLOWERING LOCUST 1 (RFT1. Here, we report the isolation and characterization of the flowering regulator Heading Date Repressor1 (HDR1 in rice. The hdr1 mutant exhibits an early flowering phenotype under natural LD in a paddy field in Beijing, China (39°54'N, 116°23'E, as well as under LD but not SD in a growth chamber, indicating that HDR1 may functionally regulate flowering time via the photoperiod-dependent pathway. HDR1 encodes a nuclear protein that is most active in leaves and floral organs and exhibits a typical diurnal expression pattern. We determined that HDR1 is a novel suppressor of flowering that upregulates Hd1 and downregulates Ehd1, leading to the downregulation of Hd3a and RFT1 under LDs. We have further identified an HDR1-interacting kinase, OsK4, another suppressor of rice flowering under LDs. OsK4 acts similarly to HDR1, suppressing flowering by upregulating Hd1 and downregulating Ehd1 under LDs, and OsK4 can phosphorylate HD1 with HDR1 presents. These results collectively reveal the transcriptional regulators of Hd1 for the day-length-dependent control of flowering time in rice.

  5. A segmentation and point-matching enhanced efficient deformable image registration method for dose accumulation between HDR CT images

    International Nuclear Information System (INIS)

    Zhen, Xin; Chen, Haibin; Zhou, Linghong; Yan, Hao; Jiang, Steve; Jia, Xun; Gu, Xuejun; Mell, Loren K; Yashar, Catheryn M; Cervino, Laura

    2015-01-01

    Deformable image registration (DIR) of fractional high-dose-rate (HDR) CT images is challenging due to the presence of applicators in the brachytherapy image. Point-to-point correspondence fails because of the undesired deformation vector fields (DVF) propagated from the applicator region (AR) to the surrounding tissues, which can potentially introduce significant DIR errors in dose mapping. This paper proposes a novel segmentation and point-matching enhanced efficient DIR (named SPEED) scheme to facilitate dose accumulation among HDR treatment fractions. In SPEED, a semi-automatic seed point generation approach is developed to obtain the incremented fore/background point sets to feed the random walks algorithm, which is used to segment and remove the AR, leaving empty AR cavities in the HDR CT images. A feature-based ‘thin-plate-spline robust point matching’ algorithm is then employed for AR cavity surface points matching. With the resulting mapping, a DVF defining on each voxel is estimated by B-spline approximation, which serves as the initial DVF for the subsequent Demons-based DIR between the AR-free HDR CT images. The calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative analysis and visual inspection of the DIR results indicate that SPEED can suppress the impact of applicator on DIR, and accurately register HDR CT images as well as deform and add interfractional HDR doses. (paper)

  6. A segmentation and point-matching enhanced efficient deformable image registration method for dose accumulation between HDR CT images

    Science.gov (United States)

    Zhen, Xin; Chen, Haibin; Yan, Hao; Zhou, Linghong; Mell, Loren K.; Yashar, Catheryn M.; Jiang, Steve; Jia, Xun; Gu, Xuejun; Cervino, Laura

    2015-04-01

    Deformable image registration (DIR) of fractional high-dose-rate (HDR) CT images is challenging due to the presence of applicators in the brachytherapy image. Point-to-point correspondence fails because of the undesired deformation vector fields (DVF) propagated from the applicator region (AR) to the surrounding tissues, which can potentially introduce significant DIR errors in dose mapping. This paper proposes a novel segmentation and point-matching enhanced efficient DIR (named SPEED) scheme to facilitate dose accumulation among HDR treatment fractions. In SPEED, a semi-automatic seed point generation approach is developed to obtain the incremented fore/background point sets to feed the random walks algorithm, which is used to segment and remove the AR, leaving empty AR cavities in the HDR CT images. A feature-based ‘thin-plate-spline robust point matching’ algorithm is then employed for AR cavity surface points matching. With the resulting mapping, a DVF defining on each voxel is estimated by B-spline approximation, which serves as the initial DVF for the subsequent Demons-based DIR between the AR-free HDR CT images. The calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative analysis and visual inspection of the DIR results indicate that SPEED can suppress the impact of applicator on DIR, and accurately register HDR CT images as well as deform and add interfractional HDR doses.

  7. Evaluation of the Kerma at the entrance of the labyrin thin in facilities with Co-60 HDR brachytherapy

    International Nuclear Information System (INIS)

    Pujades, M. C.; Granero, D.; Ballester, F.; Perez-Calatayud, J.; Vijande, J.

    2013-01-01

    The purpose of this study is to evaluate the kerma's collision at the entrance of the labyrinth adapting the methodology of the NCRP-151 to a bunker of brachytherapy with Co-60, similar to the one carried out in a previous work with HDR Ir-192. To validate the result is simulated using techniques Monte Carlo (MC) two typical designs of HDR with Co-60 bunker. (Author)

  8. Modelle in die onderrig van fisika

    Directory of Open Access Journals (Sweden)

    J. J. A. Smit

    1998-07-01

    Full Text Available Die rol van modelle in die onderrig van fisika is sedert die vroeë tagtigerjare erken. In die onderrig word die absent op die kwantitaiewe aspekte van die vak geplaas, terwyl die kwatitatiewe aspekte min aandag kry.

  9. DIE SAGD - SY ONTSTAAN EN ONTWIKKELING

    African Journals Online (AJOL)

    31 Okt 1977 ... stelling van 'n higiene afdeling het in 'n belang- rike behoefte voorsien. Die pligte van die SAGO het dus op hierdie stadium die ondersoek van soldate, die sanita- sie van kampe, die verpleging van pasiente in militere hospitale en die opleiding van lede be- hels. 'n Hoogtepunt was die opening van die.

  10. Dimensional control of die castings

    Science.gov (United States)

    Karve, Aniruddha Ajit

    The demand for net shape die castings, which require little or no machining, is steadily increasing. Stringent customer requirements are forcing die casters to deliver high quality castings in increasingly short lead times. Dimensional conformance to customer specifications is an inherent part of die casting quality. The dimensional attributes of a die casting are essentially dependent upon many factors--the quality of the die and the degree of control over the process variables being the two major sources of dimensional error in die castings. This study focused on investigating the nature and the causes of dimensional error in die castings. The two major components of dimensional error i.e., dimensional variability and die allowance were studied. The major effort of this study was to qualitatively and quantitatively study the effects of casting geometry and process variables on die casting dimensional variability and die allowance. This was accomplished by detailed dimensional data collection at production die casting sites. Robust feature characterization schemes were developed to describe complex casting geometry in quantitative terms. Empirical modeling was utilized to quantify the effects of the casting variables on dimensional variability and die allowance for die casting features. A number of casting geometry and process variables were found to affect dimensional variability in die castings. The dimensional variability was evaluated by comparisons with current published dimensional tolerance standards. The casting geometry was found to play a significant role in influencing the die allowance of the features measured. The predictive models developed for dimensional variability and die allowance were evaluated to test their effectiveness. Finally, the relative impact of all the components of dimensional error in die castings was put into perspective, and general guidelines for effective dimensional control in the die casting plant were laid out. The results of

  11. Die transvaalse ontwerp-ordonnansie oor die onderwys

    Directory of Open Access Journals (Sweden)

    J. C. Coetzee

    1952-03-01

    Full Text Available In ’n Buitengewone Provinsiale Koerant van die Provinsie Transvaal is onder datum 25 Junie 1952 gepubliseer ’n „Ontwerp-Ordonnansie tot samevatting en wysiging van die Wette betreffende die Sentrale Beheer van die Onderwys, die Plaaslike Beheer van Skole, Godsdiensonderrig in Openbare Skole, Taal en die Onderwys, Onderwyspersoneel, Verpligte Onderwys, Toelating van Leerlinge tot Skole, Klasse of Inrigtings, Openbare Onderwys, Private Skole, Onderwys vir Kleurlinge en Asiate en Onderwys vir Naturelle, en om vir sake in verband daarmee voorsiening te maak” .

  12. DIE HEDENDAAGSE SIENING VAN DIE NORMERING VAN DUITS ...

    African Journals Online (AJOL)

    v a k t a a l k w a l i £ i k a s i e s ) neem d i e I n s t i t u t t a l l e take waar ter u i t b r e i d i n g van kennis van die Duitse taal in die buiteland. Sedert 1964 publiseer die. Institut die tydskrif Deutsch als Fremdsprache met die bylae Sprachpraxis, asook 'n handboek met die titel Deutsch - eln Lehrbuch Eur Auslander (Duits.

  13. Navigating "Assisted Dying".

    Science.gov (United States)

    Schipper, Harvey

    2016-02-01

    Carter is a bellwether decision, an adjudication on a narrow point of law whose implications are vast across society, and whose impact may not be realized for years. Coupled with Quebec's Act Respecting End-of-life Care it has sharply changed the legal landscape with respect to actively ending a person's life. "Medically assisted dying" will be permitted under circumstances, and through processes, which have yet to be operationally defined. This decision carries with it moral assumptions, which mean that it will be difficult to reach a unifying consensus. For some, the decision and Act reflect a modern acknowledgement of individual autonomy. For others, allowing such acts is morally unspeakable. Having opened the Pandora's Box, the question becomes one of navigating a tolerable societal path. I believe it is possible to achieve a workable solution based on the core principle that "medically assisted dying" should be a very rarely employed last option, subject to transparent ongoing review, specifically as to why it was deemed necessary. My analysis is based on 1. The societal conditions in which have fostered demand for "assisted dying", 2. Actions in other jurisdictions, 3. Carter and Quebec Bill 52, 4. Political considerations, 5. Current medical practice. Leading to a series of recommendations regarding. 1. Legislation and regulation, 2. The role of professional regulatory agencies, 3. Medical professions education and practice, 4. Public education, 5. Health care delivery and palliative care. Given the burden of public opinion, and the legal steps already taken, a process for assisted-dying is required. However, those legal and regulatory steps should only be considered a necessary and defensive first step in a two stage process. The larger goal, the second step, is to drive the improvement of care, and thus minimize assisted-dying.

  14. Management of a HDR brachytherapy system in the Hospital Juarez of Mexico

    International Nuclear Information System (INIS)

    Serrano F, A.G.; Ramirez R, G.; Gil G, R.; Azorin N, J.; Rivera M, T.

    2007-01-01

    Full text: In the Hospital Juarez of Mexico, it is carried out a project to implement a Brachytherapy system with high dose rate (HDR) through a Management quality program. In our work center this treatment modality in patients with cervicouterine cancer is used (CaCu), and constantly it is necessary to carry out improvements in the procedures, with the purpose of optimizing them and in consequence to complete the principles of the Radiological Protection, guaranteeing this way, an attention with the quality and safety, such that allow to diminish the risks to the patients and to assure that the received dose in critical organs it finds inside the permitted therapeutic limits, without commit the radiosensitive response of healthy organs. In this work an analysis of the implementation of this system is presented, detailing the procedures so much in the technological infrastructure like human and indicating the necessary technical and operative requirements to reach an adequate practice in HDR brachytherapy. (Author)

  15. Essential results of analyses accompanying the leak rate experiments E22 at HDR

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1994-01-01

    Under the E22 test group of phase III of the HDR safety programme, experiments were performed on the crack opening and leak rate behaviour of pipe components of smaller nominal bores. The experiments were complemented by computations, in particular verifications, to qualify the computation models as one of the main aims of the HDR safety programme. Most of the analyses to determine crack openings were performed by means of the finite-element method, including elastic-plastic materials behaviour and, complementarily, assessing engineering methods. The leak rate was calculated by means of separate 2-phase computation models. Altogether, it may be concluded from the structural and fracture mechanical experiments with pipes, elbows and branch pieces, that crack openings and incipient cracks at loading with internal pressure or bending moment can be described with good accuracy by means of the finite-element programme ADINA and the developed FE-models. (orig.) [de

  16. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    International Nuclear Information System (INIS)

    Reyes-Rivera, E.; Sosa, M.; Reyes, U.; Jesús Bernal-Alvarado, José de; Córdova, T.; Gil-Villegas, A.; Monzón, E.

    2014-01-01

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy

  17. HDR Pathological Image Enhancement Based on Improved Bias Field Correction and Guided Image Filter

    Directory of Open Access Journals (Sweden)

    Qingjiao Sun

    2016-01-01

    Full Text Available Pathological image enhancement is a significant topic in the field of pathological image processing. This paper proposes a high dynamic range (HDR pathological image enhancement method based on improved bias field correction and guided image filter (GIF. Firstly, a preprocessing including stain normalization and wavelet denoising is performed for Haematoxylin and Eosin (H and E stained pathological image. Then, an improved bias field correction model is developed to enhance the influence of light for high-frequency part in image and correct the intensity inhomogeneity and detail discontinuity of image. Next, HDR pathological image is generated based on least square method using low dynamic range (LDR image, H and E channel images. Finally, the fine enhanced image is acquired after the detail enhancement process. Experiments with 140 pathological images demonstrate the performance advantages of our proposed method as compared with related work.

  18. Dosimetric study of surface applicators of HDR brachytherapy GammaMed Plus equipment

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Rivera, E., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Sosa, M., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Reyes, U., E-mail: eric-1985@fisica.ugto.mx, E-mail: modesto@fisica.ugto.mx, E-mail: uvaldoreyes@fisica.ugto.mx; Jesús Bernal-Alvarado, José de, E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Córdova, T., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx; Gil-Villegas, A., E-mail: bernal@fisica.ugto.mx, E-mail: theo@fisica.ugto.mx, E-mail: gil@fisica.ugto.mx [División de Ciencias e Ingenierías, Universidad de Guanajuato, 37150 León, Gto. (Mexico); Monzón, E., E-mail: emonzon@imss.gob.mx [Unidad de Alta Especialidad No.1, Instituto Mexicano del Seguro Social, Léon, Gto. (Mexico)

    2014-11-07

    The cone type surface applicators used in HDR brachytherapy for treatment of small skin lesions are an alternative to be used with both electron beams and orthovoltage X-ray equipment. For a good treatment planning is necessary to know the dose distribution of these applicators, which can be obtained by experimental measurement and Monte Carlo simulation as well. In this study the dose distribution of surface applicators of 3 and 3.5 cm diameter, respectively of HDR brachytherapy GammaMed Plus equipment has been estimated using the Monte Carlo method, MCNP code. The applicators simulated were placed on the surface of a water phantom of 20 × 20 × 20 cm and the dose was calculated at depths from 0 to 3 cm with increments of 0.25 mm. The dose profiles obtained at depth show the expected gradients for surface therapy.

  19. Die historiese betroubaarheid van die aartsvadervertellinge. 'n Beknopte bespreking van die huidige debat na aanleiding van die jongste publikasie

    Directory of Open Access Journals (Sweden)

    W. Vosloo

    1982-08-01

    Full Text Available Die afgelope twintig jaar was daar �n toenemende belangstelling in die aartsvadervertellinge in Genesis. Benewens die talle tydskrifartikels het skrywers soos die volgende ook boeke oor die onderwerp die lig laat sien: A. Parrot (1962, W. M. Clark (1964, R. Kilian (1966, R. E. Clements (1967, N. Lohfink (1967, H. Weidemann (1968, R. Martin-Achard (1969, T. L. Thompson (1974, J. van Seters (1975, J. P. Fokkelman (1975, C. Westermann (1976, R. Rendtorff (1977, J. Bright (1977, W. McKane (1979 en A. R. Millard en D. J. Wiseman (1980.

  20. 'n Kwalitatiewe ondersoek na die invloed van aspekte van die ...

    African Journals Online (AJOL)

    S Blignaut

    ISSN 0378-5254 Journal of Family Ecology and Consumer Sciences, Vol 26: No1, 1998. 15 ...... van byvoorbeeld die televisie en gedrukte media 'n invloed op die .... fashion promotion and advertising. New York. ... Consumer behaviour to-.

  1. Use of CT or MR dosimetry in high dose rate (HDR) brachytherapy for prostate cancer

    International Nuclear Information System (INIS)

    Liu, C.; Das, R.; See, A.; Duchesne, G.M.; Van Dyk, S.; Tai, K.H.

    2003-01-01

    Brachytherapy (BT) has, in recent years, become a well-utilised treatment option for prostate cancer. Tumour control probability relies on accurate dosimetry, which in turn relies on the accurate definition of the prostate gland. In external beam radiotherapy and BT, MRI has been shown to be a superior imaging modality when delineating the prostate gland especially at the apex. To date, data on MRI planning in prostate BT has focussed mainly on permanent interstitial implants. No data currently exists comparing MRI vs CT planning in HDR BT and its subsequent impact on prostate dosimetry. To determine the effects of MRI vs CT in HDR BT with respect to prostatic volumes and normal tissue doses, with the evaluations made using dose-volume histograms (DVH). Dosimetry parameters derived using CT and MRI (T2 weighted) scans of 11 patients who had received TRUS guided implants for HDR BT, were compared using the PlatoTM computer planning system. Treatment plans were generated on volumes marked by the same radiation oncologist for each patient. Comparison was made of the treatment plans (dosimetry) between: 1. CT generated plans; 2. CT generated plans assessed using MRI marked volumes and 3. MRI generated plans. We confirm the previously reported results that CT scans can overestimate prostatic volumes compared with MRI. Variations were noted in CT and MRI based plans that may allow improved sparing of the rectum and urethra when using MRI planning. The main disadvantages of using MRI scans are access to facilities as well as identifying a dummy source to adequately define the tips of our catheters. It is feasible to utilise MRI scans for HDR BT planning. The clearer definition of anatomical structures has added advantages when contouring the prostate

  2. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices

    International Nuclear Information System (INIS)

    Siauw, Timmy; Cunha, Adam; Atamtuerk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2011-01-01

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria. Methods: The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Results: Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) Core TM 2 Duo CPU 1.67 GHz processor with 3 Gib RAM. Conclusions: IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.

  3. 3-D conformal HDR brachytherapy as monotherapy for localized prostate cancer. A pilot study

    International Nuclear Information System (INIS)

    Martin, T.; Baltas, D.; Kurek, R.; Roeddiger, S.; Kontova, M.; Anagnostopoulos, G.; Skazikis, G.; Zamboglou, N.; Dannenberg, T.; Buhleier, T.; Tunn, U.

    2004-01-01

    Purpose: pilot study to evaluate feasibility, acute toxicity and conformal quality of three-dimensional (3-D) conformal high-dose-rate (HDR) brachytherapy as monotherapy for localized prostate cancer using intraoperative real-time planning. Patients and methods: between 05/2002 and 05/2003, 52 patients with prostate cancer, prostate-specific antigen (PSA) ≤ 10 ng/ml, Gleason score ≤ 7 and clinical stage ≤ T2a were treated. Median PSA was 6.4 ng/ml and median Gleason score 5. 24/52 patients had stage T1c and 28/52 stage T2a. For transrectal ultrasound-(TRUS-)guided transperineal implantation of flexible plastic needles into the prostate, the real-time HDR planning system SWIFT trademark was used. After implantation, CT-based 3-D postplanning was performed. All patients received one implant for four fractions of HDR brachytherapy in 48 h using a reference dose (D ref ) of 9.5 Gy to a total dose of 38.0 Gy. Dose-volume histograms (DVHs) were analyzed to evaluate the conformal quality of each implant using D 90 , D 10 urethra, and D 10 rectum. Acute toxicity was evaluated using the CTC (common toxicity criteria) scales. Results: median D 90 was 106% of D ref (range: 93-115%), median D 10 urethra 159% of D ref (range: 127-192%), and median D 10 rectum 55% of D ref (range: 35-68%). Median follow-up is currently 8 months. In 2/52 patients acute grade 3 genitourinary toxicity was observed. No gastrointestinal toxicity > grade 1 occurred. Conclusion: 3-D conformal HDR brachytherapy as monotherapy using intraoperative real-time planning is a feasible and highly conformal treatment for localized prostate cancer associated with minimal acute toxicity. Longer follow-up is needed to evaluate late toxicity and biochemical control. (orig.)

  4. Is there any place for LDR brachytherapy for head and neck carcinomas in HDR era?

    OpenAIRE

    Fijuth, Jacek

    2009-01-01

    In Poland, the classical LDR brachytherapy for head and neck carcinomas with Ir-192 wires or hairpins has completely disappeared some time ago after 30 years of successful clinical use. Can this technique be fully and safely replaced by HDR or PDR application? This option seems attractive because of new possibilities of 3D reconstruction and computer real-time treatment planning and optimization. However, in my opinion, long time is needed to get a clinical and scientific experience that has ...

  5. SU-E-J-270: Study of PET Response to HDR Brachytherapy of Rectal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, R; Le, Y; Armour, E; Efron, J; Azad, N; Wahl, R; Gearhart, S; Herman, J [Johns Hopkins University, Baltimore, MD (United States)

    2014-06-01

    Purpose: Dose-response studies in radiation therapy are typically using single response values for tumors across ensembles of tumors. Using the high dose rate (HDR) treatment plan dose grid and pre- and post-therapy FDG-PET images, we look for correlations between voxelized dose and FDG uptake response in individual tumors. Methods: Fifteen patients were treated for localized rectal cancer using 192Ir HDR brachytherapy in conjunction with surgery. FDG-PET images were acquired before HDR therapy and 6–8 weeks after treatment (prior to surgery). Treatment planning was done on a commercial workstation and the dose grid was calculated. The two PETs and the treatment dose grid were registered to each other using non-rigid registration. The difference in PET SUV values before and after HDR was plotted versus absorbed radiation dose for each voxel. The voxels were then separated into bins for every 400 cGy of absorbed dose and the bin average values plotted similarly. Results: Individual voxel doses did not correlate with PET response; however, when group into tumor subregions corresponding to dose bins, eighty percent of the patients showed a significant positive correlation (R2 > 0) between PET uptake difference in the targeted region and the absorbed dose. Conclusion: By considering larger ensembles of voxels, such as organ average absorbed dose or the dose bins considered here, valuable information may be obtained. The dose-response correlations as measured by FDG-PET difference potentially underlines the importance of FDG-PET as a measure of response, as well as the value of voxelized information.

  6. Modeling the Mechanical Performance of Die Casting Dies

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller

    2004-02-27

    The following report covers work performed at Ohio State on modeling the mechanical performance of dies. The focus of the project was development and particularly verification of finite element techniques used to model and predict displacements and stresses in die casting dies. The work entails a major case study performed with and industrial partner on a production die and laboratory experiments performed at Ohio State.

  7. N HERSIENING VAN DIE AFRIKAANSE VERTALING VAN DIE ...

    African Journals Online (AJOL)

    Test

    vergewe. Dit sou in orde gewees het as daar gestaan het, ReMomë- j^onta^is hepta?ds. wat die grieks is vir sewentig maal sewe. Die uitdrukking. heMom&ontabis heptd sien hoogswaarskynlik op Gen. 4 : 24 (LXX) waar. Lameg meedeel dat hy sewe-en-sewentig-maal gewreek sal word. Daar sit die Afr. Vert, die uitdrukking ...

  8. Film Presentation: Die Urknallmaschine

    CERN Multimedia

    Carolyn Lee

    2010-01-01

    Die Urknallmaschine, an Austrian film by Gerd Baldauf, narrated by Norbert Frischauf (Alpha Österreich - ORF, 2009).  In CERN’s gigantic complex particles are accelerated to almost the speed of light, brought to collision and made to divide into even smaller particles. Public opinion of CERN’s research is also divided. Sceptics fear that black holes may be created. Might the goal to study the origin of the world lead to its destruction? The Austrian researcher Norbert Frischauf worked at CERN for many years. With his guidance it is possible to explore the world’s largest research centre, get a glimpse of the fascinating work the scientists do there and take a crash course in particle physics. Die Urknallmaschine will be presented on Friday, 25 June from 13:00 to 14:00 in the Main Auditorium. Language: German

  9. Dying for security

    Directory of Open Access Journals (Sweden)

    Buchan, Bruce

    2011-01-01

    Full Text Available If political statements and media coverage are any guide, it seems Australians today are dying for security. At no other moment in our history has the spectre of war and terrorism so haunted popular, political and scholarly perceptions of Australia’s colonial past and of its geopolitical future. And yet, debates over colonial war or genocide and contemporary terrorism have been conducted in more or less complete isolation. In this article I argue that our contemporary obsession with ‘security’ is premised on the perennial threat of ‘insecurity’. This is the problem of in/security, and it has played a central role in the development of Western political thought. More importantly, its formulation in Western political thought provided a powerful justification for the violence of the early decades of Australia’s colonisation during which Indigenous Australians could also be said to have been dying for security.

  10. Dying for Security

    Directory of Open Access Journals (Sweden)

    Bruce Buchan

    2011-03-01

    Full Text Available If political statements and media coverage are any guide, it seems Australians today are dying for security. At no other moment in our history has the spectre of war and terrorism so haunted popular, political and scholarly perceptions of Australia’s colonial past and of its geopolitical future. And yet, debates over colonial war or genocide and contemporary terrorism have been conducted in more or less complete isolation. In this article I argue that our contemporary obsession with ‘security’ is premised on the perennial threat of ‘insecurity’. This is the problem of in/security, and it has played a central role in the development of Western political thought. More importantly, its formulation in Western political thought provided a powerful justification for the violence of the early decades of Australia’s colonisation during which Indigenous Australians could also be said to have been dying for security.

  11. N HERSIENING VAN DIE AFRIKAANSE VERTALING VAN DIE ...

    African Journals Online (AJOL)

    Test

    aangetoon het, 'n huis in Kapernaum gehad en hierdie geskiedenis speel in Kapernaum of daar digby af. Jesus en sy dissipele het namelik, volgens 6:35 geland by Gennesaret, net suid van Kapernaum Die gevolgtrekking word ondersteun deur Joh. 6:17 waarvolgens die dissi pele na die spysiging op Kapernaum gevaar ...

  12. 'n Verkenning van die soorte vennootskappe in die Amerikaanse reg ...

    African Journals Online (AJOL)

    In die Amerikaanse literatuur word talle verwysings gevind na die vennootskap in mynbou ("mining partnership"), familievennootskap ("family partnership", vennootskap in vaste eiendom ("partnership in real estate") en vennootskap vir boerdery ("farming partnership"). Hierdie onderskeiding is primer gebaseer op die tipe ...

  13. Geslagsverskille in die ouditiewe ontlokte potensiaal van die brein

    Directory of Open Access Journals (Sweden)

    Anita D Stuart

    2006-10-01

    Full Text Available Gender differences in the auditory evoked potential of the brain. Based on literature indications of an association between temperament characteristics and the evoked potential of the brain, and indications of gender differences in certain temperament traits, the purpose of this study was to ascertain whether evoked responses also differentiated between the genders. A sample of 81 male and 210 female students was randomly selected. Two auditory evoked potential procedures were applied. The results indicated statistically significant differences in evoked potential responses between the genders. The results are interpreted against the background of sensory and neurological sources of the evoked potential responses and linked to the neurophysiological foundations of temperament. Opsomming: Gegrond op aanduidings in die literatuur van ’n assosiasie tussen temperamentskenmerke en die ontlokte potensiaal van die brein, sowel as aanduidings van geslagsverskille in sekere temperamentstrekke, was die doel van die huidige studie om te bepaal of ontloktepotensiaal-response ook tussen die geslagte onderskei. ’n Steekproef van 81 manlike en 210 vroulike studente is ewekansig geselekteer. Twee ouditiewe ontloktepotensiaal- prosedures is toegepas. Die resultate het op statisties beduidende verskille tussen die geslagte gedui. Die bevindinge word teen die agtergrond van die sensoriese en neurologiese oorsprong van ontloktepotensiaal–response geïnterpreteer en verbind aan die neurofisiologiese verankering van temperament.

  14. Die 'postmoderne' stempel in die Nuwe-Testamentiese hermeneutiek

    African Journals Online (AJOL)

    georiënteerde teorie en kritiek wat volgens Moore opbou tot 'n herhaling binne. Bybelnavorsing. Dit het reeds by Immanuel Kant begin. Sedert Kant is dit proble- maties cm die objek van kennis te beskou as iets wat kennis objektief in sigself bevat. Objektiwisme is prys gegee. Dialektiek het in die plek daarvan gekom. Die.

  15. duele verse sowel as die somtotaal die leser

    African Journals Online (AJOL)

    27 Jan 2006 ... selfs 'n landkaart afgedruk) terwyl dit ter- selfdertyd ver bo die lokale uitstyg. Die digter is sterk bewus van sy omgewing, geskiedenis en tradisies, maar veral van die algemene menslike kondisie wat binne hierdie referensiekader vergestalt word. Hy gebruik 'n bekende historiese slagveld as bundeltitel (en ...

  16. Die Leben Einsteins eine Reise durch die Geschichte der Physik

    CERN Document Server

    Fiami

    2005-01-01

    Jeder kennt die Namen Einstein, Newton oder Galilei. aber was weiss man über sie? Hier ein Porträt Einsteins anhand von sechs Meilensteinen aus der Geschichte der Physik. Einstein tritt auf als Protagonist in verschiedenen Epochen und bei verschiedenen Entdeckungen, die die Welt verändert haben.

  17. DIE KONINGSBEDE AS ELEMENT IN DIE KRONINGSRITUEEL. By ...

    African Journals Online (AJOL)

    Test

    Die offerfees te Gibeon was 'n plegtigheid, waaraan geheel Israel deelgeneem het. Die duisend. "brandoffers" wat sowel Kon. as Kron. vermeld, sal wel opgevat moet word as „brandoffers en dankoffers", sodat daar vir die aanwesiges. *n groot feesmaaltyd aangerig is, vgl. I Kon. 3:15. n Sodanige maal- tyd verbind vors en ...

  18. Ruimtelike beplanning: die rol van die stads - en streeksbeplanner ...

    African Journals Online (AJOL)

    Ruimtelike beplanning: die rol van die stads - en streeksbeplanner in die saw. R Erasmus. Abstract. Since 1978 regional and town planners are employed in the SADF on a permanent basis as well as in the capacity of national service men. These men are all academically qualified and as such satisfy a need that developed ...

  19. n opinie oor die behaviouristiese siening versus die fenomenologie ...

    African Journals Online (AJOL)

    verband die eksperimente van Pavlov, Thorndike,. Skinner, Tolmann en Hull.) Fenomenologie. Die fenomenologie is 'n essensie-openbarende denkrigting. Dit impliseer'n denkende soektog na dit wat 'n besondere verskynsel of werklikheid maak juis dit wat dit is en nie iets anders nie. In die fenomenologiese antropologie ...

  20. Application of the Monte Carlo integration method in calculations of dose distributions in HDR-Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Baltas, D; Geramani, K N; Ioannidis, G T; Kolotas, C; Zamboglou, N [Strahlenklinik, Stadtische Kliniken Offenbach, Offenbach (Germany); Giannouli, S [Department of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece)

    1999-12-31

    Source anisotropy is a very important factor in brachytherapy quality assurance of high dose rate HDR Ir 192 afterloading stepping sources. If anisotropy is not taken into account then doses received by a brachytherapy patient in certain directions can be in error by a clinically significant amount. Experimental measurements of anisotropy are very labour intensive. We have shown that within acceptable limits of accuracy, Monte Carlo integration (MCI) of a modified Sievert integral (3D generalisation) can provide the necessary data within a much shorter time scale than can experiments. Hence MCI can be used for routine quality assurance schedules whenever a new design of HDR or PDR Ir 192 is used for brachytherapy afterloading. Our MCI calculation results are comparable with published experimental data and Monte Carlo simulation data for microSelectron and VariSource Ir 192 sources. We have shown not only that MCI offers advantages over alternative numerical integration methods, but also that treating filtration coefficients as radial distance-dependent functions improves Sievert integral accuracy at low energies. This paper also provides anisotropy data for three new Ir 192 sources, one for microSelectron-HDR and two for the microSelectron-PDR, for which data currently is not available. The information we have obtained in this study can be incorporated into clinical practice.

  1. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  2. The Ansel Adams zone system: HDR capture and range compression by chemical processing

    Science.gov (United States)

    McCann, John J.

    2010-02-01

    We tend to think of digital imaging and the tools of PhotoshopTM as a new phenomenon in imaging. We are also familiar with multiple-exposure HDR techniques intended to capture a wider range of scene information, than conventional film photography. We know about tone-scale adjustments to make better pictures. We tend to think of everyday, consumer, silver-halide photography as a fixed window of scene capture with a limited, standard range of response. This description of photography is certainly true, between 1950 and 2000, for instant films and negatives processed at the drugstore. These systems had fixed dynamic range and fixed tone-scale response to light. All pixels in the film have the same response to light, so the same light exposure from different pixels was rendered as the same film density. Ansel Adams, along with Fred Archer, formulated the Zone System, staring in 1940. It was earlier than the trillions of consumer photos in the second half of the 20th century, yet it was much more sophisticated than today's digital techniques. This talk will describe the chemical mechanisms of the zone system in the parlance of digital image processing. It will describe the Zone System's chemical techniques for image synthesis. It also discusses dodging and burning techniques to fit the HDR scene into the LDR print. Although current HDR imaging shares some of the Zone System's achievements, it usually does not achieve all of them.

  3. Vibrational experiments at the HDR [Heissdampfreaktor]: SHAG results and planning for SHAM

    International Nuclear Information System (INIS)

    Kot, C.A.; Malcher, L.; Steinhilber, H.

    1987-01-01

    As part of the second phase of vibrational/earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, high-level shaker tests (SHAG) were performed during June and July 1986 using a coast-down shaker capable of generating 1000 tons of force. The purpose of these experiments was to investigate full-scale structural response, soil/structure interaction, and piping and equipment response under strong excitation conditions. While global safety considerations imposed load limitations, the HDR soil/structure system was nevertheless tested to incipient failure. The performance of pipe support systems in as many as seven different multiple support pipe hanger configurations, ranging from flexible to stiff systems, was evaluated in the tests. Data obtained in the tests are used to validate analysis methods. The vibrational/earthquake investigations at the HDR are continuing with the SHAM experiments, planned for the spring of 1988. In these experiments the VKL piping loop will be subjected to direct multiple-point excitation at extremely high levels. The objective is to investigate different pipe support configurations at extreme loading, to establish seismic margins for piping, and to investigate possible failure/plastification modes in an in situ piping system

  4. Interactive multiobjective optimization for anatomy-based three-dimensional HDR brachytherapy

    Science.gov (United States)

    Ruotsalainen, Henri; Miettinen, Kaisa; Palmgren, Jan-Erik; Lahtinen, Tapani

    2010-08-01

    In this paper, we present an anatomy-based three-dimensional dose optimization approach for HDR brachytherapy using interactive multiobjective optimization (IMOO). In brachytherapy, the goals are to irradiate a tumor without causing damage to healthy tissue. These goals are often conflicting, i.e. when one target is optimized the other will suffer, and the solution is a compromise between them. IMOO is capable of handling multiple and strongly conflicting objectives in a convenient way. With the IMOO approach, a treatment planner's knowledge is used to direct the optimization process. Thus, the weaknesses of widely used optimization techniques (e.g. defining weights, computational burden and trial-and-error planning) can be avoided, planning times can be shortened and the number of solutions to be calculated is small. Further, plan quality can be improved by finding advantageous trade-offs between the solutions. In addition, our approach offers an easy way to navigate among the obtained Pareto optimal solutions (i.e. different treatment plans). When considering a simulation model of clinical 3D HDR brachytherapy, the number of variables is significantly smaller compared to IMRT, for example. Thus, when solving the model, the CPU time is relatively short. This makes it possible to exploit IMOO to solve a 3D HDR brachytherapy optimization problem. To demonstrate the advantages of IMOO, two clinical examples of optimizing a gynecologic cervix cancer treatment plan are presented.

  5. Interactive multiobjective optimization for anatomy-based three-dimensional HDR brachytherapy

    International Nuclear Information System (INIS)

    Ruotsalainen, Henri; Miettinen, Kaisa; Palmgren, Jan-Erik; Lahtinen, Tapani

    2010-01-01

    In this paper, we present an anatomy-based three-dimensional dose optimization approach for HDR brachytherapy using interactive multiobjective optimization (IMOO). In brachytherapy, the goals are to irradiate a tumor without causing damage to healthy tissue. These goals are often conflicting, i.e. when one target is optimized the other will suffer, and the solution is a compromise between them. IMOO is capable of handling multiple and strongly conflicting objectives in a convenient way. With the IMOO approach, a treatment planner's knowledge is used to direct the optimization process. Thus, the weaknesses of widely used optimization techniques (e.g. defining weights, computational burden and trial-and-error planning) can be avoided, planning times can be shortened and the number of solutions to be calculated is small. Further, plan quality can be improved by finding advantageous trade-offs between the solutions. In addition, our approach offers an easy way to navigate among the obtained Pareto optimal solutions (i.e. different treatment plans). When considering a simulation model of clinical 3D HDR brachytherapy, the number of variables is significantly smaller compared to IMRT, for example. Thus, when solving the model, the CPU time is relatively short. This makes it possible to exploit IMOO to solve a 3D HDR brachytherapy optimization problem. To demonstrate the advantages of IMOO, two clinical examples of optimizing a gynecologic cervix cancer treatment plan are presented.

  6. Clinical implementation of a new HDR brachytherapy device for partial breast irradiation

    International Nuclear Information System (INIS)

    Scanderbeg, Daniel J.; Yashar, Catheryn; Rice, Roger; Pawlicki, Todd

    2009-01-01

    Purpose: To present the clinical implementation of a new HDR device for partial breast irradiation, the Strut-Adjusted Volume Implant (SAVI), at the University of California, San Diego. Methods and materials: The SAVI device has multiple peripheral struts that can be differentially loaded with the HDR source. Planning criteria used for evaluation of the treatment plans included the following dose volume histogram (DVH) criteria: V90 >90%, V150 <50 cc and V200 <20 cc. Results: SAVI has been used on 20 patients to date at UC San Diego. In each case, the dose was modulated according to patient-specific anatomy to cover the tumor bed, while sparing normal tissues. The dosimetric data show that we can achieve greater than 90% coverage with respect to V90 (median of 95.3%) and also keep a low V150 and V200 dose at 24.5 and 11.2 cc, respectively. Complete treatment can be done within a 30-min time slot, which includes implant verification, setup, and irradiation time as well as wound dressing. Conclusion: SAVI has been implemented at UC San Diego for accelerated partial breast irradiation with excellent tumor bed conformance and minimal normal tissue exposure. Patient positioning is the key to identifying any inter-fraction device motion. Device asymmetry or tissue conformance has been shown to resolve itself 24 h after the device implantation. The device can be implemented into an existing HDR program with minimal effort

  7. Near constant-time optimal piecewise LDR to HDR inverse tone mapping

    Science.gov (United States)

    Chen, Qian; Su, Guan-Ming; Yin, Peng

    2015-02-01

    In a backward compatible HDR image/video compression, it is a general approach to reconstruct HDR from compressed LDR as a prediction to original HDR, which is referred to as inverse tone mapping. Experimental results show that 2- piecewise 2nd order polynomial has the best mapping accuracy than 1 piece high order or 2-piecewise linear, but it is also the most time-consuming method because to find the optimal pivot point to split LDR range to 2 pieces requires exhaustive search. In this paper, we propose a fast algorithm that completes optimal 2-piecewise 2nd order polynomial inverse tone mapping in near constant time without quality degradation. We observe that in least square solution, each entry in the intermediate matrix can be written as the sum of some basic terms, which can be pre-calculated into look-up tables. Since solving the matrix becomes looking up values in tables, computation time barely differs regardless of the number of points searched. Hence, we can carry out the most thorough pivot point search to find the optimal pivot that minimizes MSE in near constant time. Experiment shows that our proposed method achieves the same PSNR performance while saving 60 times computation time compared to the traditional exhaustive search in 2-piecewise 2nd order polynomial inverse tone mapping with continuous constraint.

  8. NOTE: Monte Carlo evaluation of kerma in an HDR brachytherapy bunker

    Science.gov (United States)

    Pérez-Calatayud, J.; Granero, D.; Ballester, F.; Casal, E.; Crispin, V.; Puchades, V.; León, A.; Verdú, G.

    2004-12-01

    In recent years, the use of high dose rate (HDR) after-loader machines has greatly increased due to the shift from traditional Cs-137/Ir-192 low dose rate (LDR) to HDR brachytherapy. The method used to calculate the required concrete and, where appropriate, lead shielding in the door is based on analytical methods provided by documents published by the ICRP, the IAEA and the NCRP. The purpose of this study is to perform a more realistic kerma evaluation at the entrance maze door of an HDR bunker using the Monte Carlo code GEANT4. The Monte Carlo results were validated experimentally. The spectrum at the maze entrance door, obtained with Monte Carlo, has an average energy of about 110 keV, maintaining a similar value along the length of the maze. The comparison of results from the aforementioned values with the Monte Carlo ones shows that results obtained using the albedo coefficient from the ICRP document more closely match those given by the Monte Carlo method, although the maximum value given by MC calculations is 30% greater.

  9. Characterization of HDR Ir-192 source for 3D planning system

    International Nuclear Information System (INIS)

    Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D.; Rubo, Rodrigo; Ferreira, Louise A.

    2011-01-01

    Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

  10. Comparative Analysis between LDR and HDR Images for Automatic Fruit Recognition and Counting

    Directory of Open Access Journals (Sweden)

    Tatiana M. Pinho

    2017-01-01

    Full Text Available Precision agriculture is gaining an increasing interest in the current farming paradigm. This new production concept relies on the use of information technology (IT to provide a control and supervising structure that can lead to better management policies. In this framework, imaging techniques that provide visual information over the farming area play an important role in production status monitoring. As such, accurate representation of the gathered production images is a major concern, especially if those images are used in detection and classification tasks. Real scenes, observed in natural environment, present high dynamic ranges that cannot be represented by the common LDR (Low Dynamic Range devices. However, this issue can be handled by High Dynamic Range (HDR images since they have the ability to store luminance information similarly to the human visual system. In order to prove their advantage in image processing, a comparative analysis between LDR and HDR images, for fruits detection and counting, was carried out. The obtained results show that the use of HDR images improves the detection performance to more than 30% when compared to LDR.

  11. Characterization of HDR Ir-192 source for 3D planning system

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D., E-mail: gabriel.fonseca@usp.b, E-mail: hyoriyaz@ipen.b, E-mail: ptsiquei@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rubo, Rodrigo [Universidade de Sao Paulo (HC/FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia; Minamisawa, Renato A., E-mail: renato.minamisawa@psi.c [Paul Scherrer Institut (PSI), Villigen (Switzerland); Ferreira, Louise A. [Universidade Estadual de Maringa (UEM), PR (Brazil). Fac. de Medicina

    2011-07-01

    Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

  12. The effect of split pixel HDR image sensor technology on MTF measurements

    Science.gov (United States)

    Deegan, Brian M.

    2014-03-01

    Split-pixel HDR sensor technology is particularly advantageous in automotive applications, because the images are captured simultaneously rather than sequentially, thereby reducing motion blur. However, split pixel technology introduces artifacts in MTF measurement. To achieve a HDR image, raw images are captured from both large and small sub-pixels, and combined to make the HDR output. In some cases, a large sub-pixel is used for long exposure captures, and a small sub-pixel for short exposures, to extend the dynamic range. The relative size of the photosensitive area of the pixel (fill factor) plays a very significant role in the output MTF measurement. Given an identical scene, the MTF will be significantly different, depending on whether you use the large or small sub-pixels i.e. a smaller fill factor (e.g. in the short exposure sub-pixel) will result in higher MTF scores, but significantly greater aliasing. Simulations of split-pixel sensors revealed that, when raw images from both sub-pixels are combined, there is a significant difference in rising edge (i.e. black-to-white transition) and falling edge (white-to-black) reproduction. Experimental results showed a difference of ~50% in measured MTF50 between the falling and rising edges of a slanted edge test chart.

  13. Independent verification of the delivered dose in High-Dose Rate (HDR) brachytherapy

    International Nuclear Information System (INIS)

    Portillo, P.; Feld, D.; Kessler, J.

    2009-01-01

    An important aspect of a Quality Assurance program in Clinical Dosimetry is an independent verification of the dosimetric calculation done by the Treatment Planning System for each radiation treatment. The present paper is aimed at creating a spreadsheet for the verification of the dose recorded at a point of an implant with radioactive sources and HDR in gynecological injuries. An 192 Ir source automatic differed loading equipment, GammaMedplus model, Varian Medical System with HDR installed at the Angel H. Roffo Oncology Institute has been used. The planning system implemented for getting the dose distribution is the BraquiVision. The sources coordinates as well as those of the calculation point (Rectum) are entered into the Excel-devised verification program by assuming the existence of a point source in each one of the applicators' positions. Such calculation point has been selected as the rectum is an organ at risk, therefore determining the treatment planning. The dose verification is performed at points standing at a sources distance having at least twice the active length of such sources, so they may be regarded as point sources. Most of the sources used in HDR brachytherapy with 192 Ir have a 5 mm active length for all equipment brands. Consequently, the dose verification distance must be at least of 10 mm. (author)

  14. An experimental MOSFET approach to characterize (192)Ir HDR source anisotropy.

    Science.gov (United States)

    Toye, W C; Das, K R; Todd, S P; Kenny, M B; Franich, R D; Johnston, P N

    2007-09-07

    The dose anisotropy around a (192)Ir HDR source in a water phantom has been measured using MOSFETs as relative dosimeters. In addition, modeling using the EGSnrc code has been performed to provide a complete dose distribution consistent with the MOSFET measurements. Doses around the Nucletron 'classic' (192)Ir HDR source were measured for a range of radial distances from 5 to 30 mm within a 40 x 30 x 30 cm(3) water phantom, using a TN-RD-50 MOSFET dosimetry system with an active area of 0.2 mm by 0.2 mm. For each successive measurement a linear stepper capable of movement in intervals of 0.0125 mm re-positioned the MOSFET at the required radial distance, while a rotational stepper enabled angular displacement of the source at intervals of 0.9 degrees . The source-dosimeter arrangement within the water phantom was modeled using the standardized cylindrical geometry of the DOSRZnrc user code. In general, the measured relative anisotropy at each radial distance from 5 mm to 30 mm is in good agreement with the EGSnrc simulations, benchmark Monte Carlo simulation and TLD measurements where they exist. The experimental approach employing a MOSFET detection system of small size, high spatial resolution and fast read out capability allowed a practical approach to the determination of dose anisotropy around a HDR source.

  15. Impact of using linear optimization models in dose planning for HDR brachytherapy

    International Nuclear Information System (INIS)

    Holm, Aasa; Larsson, Torbjoern; Carlsson Tedgren, Aasa

    2012-01-01

    Purpose: Dose plans generated with optimization models hitherto used in high-dose-rate (HDR) brachytherapy have shown a tendency to yield longer dwell times than manually optimized plans. Concern has been raised for the corresponding undesired hot spots, and various methods to mitigate these have been developed. The hypotheses upon this work is based are (a) that one cause for the long dwell times is the use of objective functions comprising simple linear penalties and (b) that alternative penalties, as these are piecewise linear, would lead to reduced length of individual dwell times. Methods: The characteristics of the linear penalties and the piecewise linear penalties are analyzed mathematically. Experimental comparisons between the two types of penalties are carried out retrospectively for a set of prostate cancer patients. Results: When the two types of penalties are compared, significant changes can be seen in the dwell times, while most dose-volume parameters do not differ significantly. On average, total dwell times were reduced by 4.2%, with a reduction of maximum dwell times by 25%, when the alternative penalties were used. Conclusions: The use of linear penalties in optimization models for HDR brachytherapy is one cause for the undesired long dwell times that arise in mathematically optimized plans. By introducing alternative penalties, a significant reduction in dwell times can be achieved for HDR brachytherapy dose plans. Although various measures for mitigating the long dwell times are already available, the observation that linear penalties contribute to their appearance is of fundamental interest.

  16. Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy

    Science.gov (United States)

    Yang, Xiaofeng; Rossi, Peter; Ogunleye, Tomi; Marcus, David M.; Jani, Ashesh B.; Mao, Hui; Curran, Walter J.; Liu, Tian

    2014-01-01

    Purpose: The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approach that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. Methods: The authors’ approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 1–3 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUS–CT image fusion. After TRUS–CT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. Results: For the phantom study, the target registration error (TRE) of gold-markers was 0.41 ± 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 ± 0.26 mm; the prostate volume difference between the authors’ approach and the MRI-based volume was 7.28% ± 0

  17. Prostate CT segmentation method based on nonrigid registration in ultrasound-guided CT-based HDR prostate brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaofeng, E-mail: xyang43@emory.edu; Rossi, Peter; Ogunleye, Tomi; Marcus, David M.; Jani, Ashesh B.; Curran, Walter J.; Liu, Tian [Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322 (United States); Mao, Hui [Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia 30322 (United States)

    2014-11-01

    Purpose: The technological advances in real-time ultrasound image guidance for high-dose-rate (HDR) prostate brachytherapy have placed this treatment modality at the forefront of innovation in cancer radiotherapy. Prostate HDR treatment often involves placing the HDR catheters (needles) into the prostate gland under the transrectal ultrasound (TRUS) guidance, then generating a radiation treatment plan based on CT prostate images, and subsequently delivering high dose of radiation through these catheters. The main challenge for this HDR procedure is to accurately segment the prostate volume in the CT images for the radiation treatment planning. In this study, the authors propose a novel approach that integrates the prostate volume from 3D TRUS images into the treatment planning CT images to provide an accurate prostate delineation for prostate HDR treatment. Methods: The authors’ approach requires acquisition of 3D TRUS prostate images in the operating room right after the HDR catheters are inserted, which takes 1–3 min. These TRUS images are used to create prostate contours. The HDR catheters are reconstructed from the intraoperative TRUS and postoperative CT images, and subsequently used as landmarks for the TRUS–CT image fusion. After TRUS–CT fusion, the TRUS-based prostate volume is deformed to the CT images for treatment planning. This method was first validated with a prostate-phantom study. In addition, a pilot study of ten patients undergoing HDR prostate brachytherapy was conducted to test its clinical feasibility. The accuracy of their approach was assessed through the locations of three implanted fiducial (gold) markers, as well as T2-weighted MR prostate images of patients. Results: For the phantom study, the target registration error (TRE) of gold-markers was 0.41 ± 0.11 mm. For the ten patients, the TRE of gold markers was 1.18 ± 0.26 mm; the prostate volume difference between the authors’ approach and the MRI-based volume was 7.28% ± 0

  18. Genitourinary Toxicity After High-Dose-Rate (HDR) Brachytherapy Combined With Hypofractionated External Beam Radiotherapy for Localized Prostate Cancer: An Analysis to Determine the Correlation Between Dose-Volume Histogram Parameters in HDR Brachytherapy and Severity of Toxicity

    International Nuclear Information System (INIS)

    Ishiyama, Hiromichi; Kitano, Masashi; Satoh, Takefumi; Kotani, Shouko; Uemae, Mineko; Matsumoto, Kazumasa; Okusa, Hiroshi; Tabata, Ken-ichi; Baba, Shiro; Hayakawa, Kazushige

    2009-01-01

    Purpose: To evaluate the severity of genitourinary (GU) toxicity in high-dose-rate (HDR) brachytherapy combined with hypofractionated external beam radiotherapy (EBRT) for prostate cancer and to explore factors that might affect the severity of GU toxicity. Methods and Materials: A total of 100 Japanese men with prostate cancer underwent 192 Ir HDR brachytherapy combined with hypofractionated EBRT. Mean (SD) dose to 90% of the planning target volume was 6.3 (0.7) Gy per fraction of HDR. After 5 fractions of HDR treatment, EBRT with 10 fractions of 3 Gy was administrated. The urethral volume receiving 1-15 Gy per fraction in HDR brachytherapy (V1-V15) and the dose to at least 5-100% of urethral volume in HDR brachytherapy (D5-D100) were compared between patients with Grade 3 toxicity and those with Grade 0-2 toxicity. Prostate volume, patient age, and International Prostate Symptom Score were also compared between the two groups. Results: Of the 100 patients, 6 displayed Grade 3 acute GU toxicity, and 12 displayed Grade 3 late GU toxicity. Regarding acute GU toxicity, values of V1, V2, V3, and V4 were significantly higher in patients with Grade 3 toxicity than in those with Grade 0-2 toxicity. Regarding late GU toxicity, values of D70, D80, V12, and V13 were significantly higher in patients with Grade 3 toxicity than in those with Grade 0-2 toxicity. Conclusions: The severity of GU toxicity in HDR brachytherapy combined with hypofractionated EBRT for prostate cancer was relatively high. The volume of prostatic urethra was associated with grade of acute GU toxicity, and urethral dose was associated with grade of late GU toxicity.

  19. Die Vier Typen von Projektmanagern

    DEFF Research Database (Denmark)

    Lund Pedersen, Carsten; Ritter, Thomas

    2018-01-01

    Bevor Sie einem Mitarbeiter die Leitung eines Projekts anvertrauen, sollten Sie sich über dessen Managementstil klar werden. Passt dieser nicht zur Art des Vorhabens, wird er scheitern. So treffen Sie die richtige Wahl....

  20. Die historiese Jesus as wondenverker

    African Journals Online (AJOL)

    Biblical Association, te wete 'The social sciences and second Testament exegesis'. John Pilch is die leier van die Society of Biblical Literature se 'Social sciences and ..... Hollenbach, P 1982. ... Stauffer, E 1982. Jesus ... London: Collins.

  1. Precision die design by the die expansion method

    CERN Document Server

    Ibhadode, A O Akii

    2009-01-01

    This book presents a new method for the design of the precision dies used in cold-forging, extrusion and drawing processes. The method is based upon die expansion, and attempts to provide a clear-cut theoretical basis for the selection of critical die dimensions for this group of precision dies when the tolerance on product diameter (or thickness) is specified. It also presents a procedure for selecting the minimum-production-cost die from among a set of design alternatives. The mathematical content of the book is relatively simple and will present no difficulty to those who have taken basic c

  2. Die Dokter-Pasient Rolverwantskap

    African Journals Online (AJOL)

    17 Aug 1974 ... en as sodanig 'n ral sped in die persoon se siektegedrag en uiteindelike patroon van hulpsoeke. SIEKEROL EN SOSIALISERING IN DIE. PASIENTROL ..... more cumulative, resulting in a more gradual social and professional maturation.' Vit die voorafgaande word dit duidelik dat Dewy se pragmatiese ...

  3. prosesseringsmetodes op die voedingswaarde van

    African Journals Online (AJOL)

    gebring is, kon geen betekenisvolle verskille tussen die drie monsters gevind word nie. Volgens Opstvedt (1976) kan ME waardes ook dien as 'n kriteria van proteien- kwaliteit, hoofsaaklik a.g.v. die verhoogde stikstofuit- skeiding in die urine wat sal plaasvind a.g.v. beskadiging van aminosure. De Groote (1968) het gevind ...

  4. SU-F-T-55: Reproducibility of Interstitial HDR Brachytherapy Plans

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Ellis, R; Traughber, B; Podder, T [University Hospitals Case Medical Center, Cleveland, OH (United States)

    2016-06-15

    Purpose: Treating gynecological cancers with interstitial high-dose-rate (HDR) brachytherapy requires precise reconstruction of catheter positions to obtain accurate dosimetric plans. In this study, we investigated the degree of reproducibility of dosimetric plans for Syed HDR brachytherapy. Methods: We randomly selected five patients having cervix-vaginal cancer who were recently treated in our clinic with interstitial HDR brachytherapy with a prescription dose of 25–30 Gy in five fractions. Interstitial needles/catheters were placed under fluoroscopic guidance and intra-operative 3T MRI scan was performed to confirm the desired catheter placement for adequate target volume coverage. A CT scan was performed and fused with the MRI for delineating high-risk CTV (HR-CTV), intermediate-risk CTV (IR-CTV) and OARs. HDR treatment plans were generated using Oncentra planning software. A single plan was used for all five fractions of treatment for each patient. For this study, we took the original clinical plan and removed all the reconstructed catheters from the plan keeping the original contours unchanged. Then, we manually reconstructed all the catheters and entered the same dwell time from the first original clinical plan. The dosimetric parameters studied were: D90 for HR-CTV and IR-CV, and D2cc for bladder, rectum, sigmoid and bowel. Results: The mean of absolute differences in dosimetric coverage (D90) were (range): 1.3% (1.0–2.0%) and 2.0% (0.9–3.6%) for HR-CTV and IR-CTV, respectively. In case of OARs, the mean of absolute variations in D2cc were (range): 4.7% (0.7–8.9%) for bladder, 1.60% (0.3–3.2%) for rectum, 1.6% (0–3.9%) for sigmoid, and 1.8% (0–5.1%) for bowel. Conclusion: Overall, the reproducibility of interstitial HDR plans was within clinically acceptable limit. Observed maximum variation in D2cc for bladder. If number of catchers and dwell points were relatively low or any one catheter was heavily loaded, then reproducibility of the plan

  5. Anatomy-based inverse planning dose optimization in HDR prostate implant: A toxicity study

    International Nuclear Information System (INIS)

    Mahmoudieh, Alireza; Tremblay, Christine; Beaulieu, Luc; Lachance, Bernard; Harel, Francois; Lessard, Etienne; Pouliot, Jean; Vigneault, Eric

    2005-01-01

    Background and purpose: The aim of this study is to evaluate the acute and late complications in patients who have received HDR implant boost using inverse planning, and to determine dose volume correlations. Patients and methods: Between September 1999 and October 2002, 44 patients with locally advanced prostate cancer (PSA ≥10 ng/ml, and/or Gleason score ≥7, and/or Stage T2c or higher) were treated with 40-45 Gy external pelvic field followed by 2-3 fraction of inverse-planned HDR implant boost (6-9.5 Gy /fraction). Median follow-up time was 1.7 years with 81.8% of patients who had at least 12 months of follow up (range 8.6-42.5. Acute and late morbidity data were collected and graded according to RTOG criteria. Questionnaires were used to collect prostate related measures of quality of life, and international prostate symptom score (IPSS) before and after treatment. Dose-volume histograms for prostate, urethra, bladder, penis bulb and rectum were analyzed. Results: The median patient age was 64 years. Of these, 32% were in the high risk group, and 61% in the intermediate risk group. 3 patients (7%) had no adverse prognostic factors. A single grade 3 GU acute toxicity was reported but no grade 3-4 acute GI toxicity. No grade 3-4 late GU or GI toxicity was reported. Acute (late) grade 2 urinary and rectal symptoms were reported in 31.8 (11.4%) and 4.6% (4.6%) of patients, respectively. A trend for predicting acute GU toxicity is seen for total HDR dose of more than 18 Gy (OR=3.6, 95%CI=[0.96-13.5], P=0.058). The evolution of toxicity is presented for acute and late GU/GI toxicity. Erectile dysfunction occurs in approximately 27% of patients who were not on hormonal deprivation, but may be taking sildenafil. The IPSS peaked on averaged 6 weeks post-implant and returned to the baseline at a median of 6 months. Conclusions: Inverse-planned HDR brachytherapy is a viable option to deliver higher dose to the prostate as a boost without increasing GU or rectal

  6. Developing A Directional High-Dose Rate (d-HDR) Brachytherapy Source

    Science.gov (United States)

    Heredia, Athena Yvonne

    Conventional sources used in brachytherapy provide nearly isotropic or radially symmetric dose distributions. Optimizations of dose distributions have been limited to varied dwell times at specified locations within a given treatment volume, or manipulations in source position for seed implantation techniques. In years past, intensity modulated brachytherapy (IMBT) has been used to reduce the amount of radiation to surrounding sensitive structures in select intracavitary cases by adding space or partial shields. Previous work done by Lin et al., at the University of Wisconsin-Madison, has shown potential improvements in conformality for brachytherapy treatments using a directionally shielded low dose rate (LDR) source for treatments in breast and prostate. Directional brachytherapy sources irradiate approximately half of the radial angles around the source, and adequately shield a quarter of the radial angles on the opposite side, with sharp gradient zones between the treated half and shielded quarter. With internally shielded sources, the radiation can be preferentially emitted in such a way as to reduce toxicities in surrounding critical organs. The objective of this work is to present findings obtained in the development of a new directional high dose rate (d-HDR) source. To this goal, 103Pd (Z = 46) is reintroduced as a potential radionuclide for use in HDR brachytherapy. 103Pd has a low average photon energy (21 keV) and relatively short half -life (17 days), which is why it has historically been used in low dose rate applications and implantation techniques. Pd-103 has a carrier-free specific activity of 75000 Ci/g. Using cyclotron produced 103Pd, near carrier-free specific activities can be achieved, providing suitability for high dose rate applications. The evolution of the d-HDR source using Monte Carlo simulations is presented, along with dosimetric parameters used to fully characterize the source. In addition, a discussion on how to obtain elemental

  7. Evaluation of water-mimicking solid phantom materials for use in HDR and LDR brachytherapy dosimetry

    Science.gov (United States)

    Schoenfeld, Andreas A.; Thieben, Maike; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2017-12-01

    In modern HDR or LDR brachytherapy with photon emitters, fast checks of the dose profiles generated in water or a water-equivalent phantom have to be available in the interest of patient safety. However, the commercially available brachytherapy photon sources cover a wide range of photon emission spectra, and the range of the in-phantom photon spectrum is further widened by Compton scattering, so that the achievement of water-mimicking properties of such phantoms involves high requirements on their atomic composition. In order to classify the degree of water equivalence of the numerous commercially available solid water-mimicking phantom materials and the energy ranges of their applicability, the radial profiles of the absorbed dose to water, D w, have been calculated using Monte Carlo simulations in these materials and in water phantoms of the same dimensions. This study includes the HDR therapy sources Nucletron Flexisource Co-60 HDR (60Co), Eckert und Ziegler BEBIG GmbH CSM-11 (137Cs), Implant Sciences Corporation HDR Yb-169 Source 4140 (169Yb) as well as the LDR therapy sources IsoRay Inc. Proxcelan CS-1 (131Cs), IsoAid Advantage I-125 IAI-125A (125I), and IsoAid Advantage Pd-103 IAPd-103A (103Pd). Thereby our previous comparison between phantom materials and water surrounding a Varian GammaMed Plus HDR therapy 192Ir source (Schoenfeld et al 2015) has been complemented. Simulations were performed in cylindrical phantoms consisting of either water or the materials RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, Plastic Water LR, Original Plastic Water (2015), Plastic Water (1995), Blue Water, polyethylene, polystyrene and PMMA. While for 192Ir, 137Cs and 60Co most phantom materials can be regarded as water equivalent, for 169Yb the materials Plastic Water LR, Plastic Water DT and RW1 appear as water equivalent. For the low-energy sources 106Pd, 131Cs and 125I, only Plastic Water LR can be classified as water equivalent.

  8. DIE SAW SE ROL IN SWA

    African Journals Online (AJOL)

    wei die verdediging van die landsgrense teen 'n vyand wat die orde, gesag, vrede, stabiliteit en welvaart in Suidwes-Afrika en die Republiek van. Suid-Afrika wil vernietig. Hierdie oorlog moet nie ge'lsoleerd gesien word nie, maar in perspektief geplaas word teen die agtergrond van 'n nag groter konflik, naamlik die van die ...

  9. Die Subjektiewe en Objektiewe doelwitte van Arbeid

    Directory of Open Access Journals (Sweden)

    T. H. Veldsman

    1982-11-01

    Die artikel gee aandag aan die subjektiewe en objektiewe doelwitte van arbeid. Hul plek en funksie binne 'n voorgestelde geïntegreerde motiveringsmodel word eerstens aangedui. Vervolgens word die verwantskap tussen die twee doelwitte uitgelig, gevolg deur 'n bespreking van die aard van die objektiewe doel. Laastens word die invloed van moderne arbeid op hierdie doelwitte uitgestippel.

  10. DIE EKSISTENSIEFILOSOFIE VAN KARL JASPERS. ENKELE ...

    African Journals Online (AJOL)

    Test

    Kierkegaard en Nietzsche, Max Weber en Dilthey, om maar enkeles te noem, en 5.) Jaspers se persoonlike beskouing oor die roe ping en die taak van die Filosofie, sy aanvoeling van die filosofiese problematiek en sy grondhouding teenoor die eksistensiële verbonden- hede. Die woord van Fichte, naamlik dat die Filosofie ...

  11. High dynamic range adaptive real-time smart camera: an overview of the HDR-ARTiST project

    Science.gov (United States)

    Lapray, Pierre-Jean; Heyrman, Barthélémy; Ginhac, Dominique

    2015-04-01

    Standard cameras capture only a fraction of the information that is visible to the human visual system. This is specifically true for natural scenes including areas of low and high illumination due to transitions between sunlit and shaded areas. When capturing such a scene, many cameras are unable to store the full Dynamic Range (DR) resulting in low quality video where details are concealed in shadows or washed out by sunlight. The imaging technique that can overcome this problem is called HDR (High Dynamic Range) imaging. This paper describes a complete smart camera built around a standard off-the-shelf LDR (Low Dynamic Range) sensor and a Virtex-6 FPGA board. This smart camera called HDR-ARtiSt (High Dynamic Range Adaptive Real-time Smart camera) is able to produce a real-time HDR live video color stream by recording and combining multiple acquisitions of the same scene while varying the exposure time. This technique appears as one of the most appropriate and cheapest solution to enhance the dynamic range of real-life environments. HDR-ARtiSt embeds real-time multiple captures, HDR processing, data display and transfer of a HDR color video for a full sensor resolution (1280 1024 pixels) at 60 frames per second. The main contributions of this work are: (1) Multiple Exposure Control (MEC) dedicated to the smart image capture with alternating three exposure times that are dynamically evaluated from frame to frame, (2) Multi-streaming Memory Management Unit (MMMU) dedicated to the memory read/write operations of the three parallel video streams, corresponding to the different exposure times, (3) HRD creating by combining the video streams using a specific hardware version of the Devebecs technique, and (4) Global Tone Mapping (GTM) of the HDR scene for display on a standard LCD monitor.

  12. Dying with dignity.

    Science.gov (United States)

    Madan, T N

    1992-08-01

    Death is a theme of central importance in all cultures, but the manner in which it is interpreted varies from society to society. Even so, traditional cultures, including Christian, Hindu and Jain religious traditions, exhibited a positive attitude to death and did not look upon it in a dualistic framework of good vs bad, or desirable vs undesirable. Nor was pessimism the dominant mood in their thinking about death itself. A fundamental paradigm shift occurred in the West in the eighteenth century when death was desacralized and transformed into a secular event amenable to human manipulation. From those early beginnings, dying and death have been thoroughly medicalized and brought under the purview of high technology in the twentieth century. Once death is seen as a problem for professional management, the hospital displaces the home, and specialists with different kinds and degrees of expertise take over from the family. Everyday speech and the religious idiom yield place to medical jargon. The subject (an ageing, sick or dying person) becomes the object of this make-believe yet real world. As the object of others' professional control, he or she loses the freedom of self-assessment, expression and choice. Or, he or she may be expected to choose when no longer able to do so. Thus, not only freedom but dignity also is lost, and lawyers join doctors in crisis manipulation and perpetuation. Although the modern medical culture has originated in the West, it has gradually spread to all parts of the world, subjugating other kinds of medical knowledge and other attitudes to dying and death.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Sal die ‘ewolusie’ vanaf biologie na lewenswetenskappe ‘uitsterwing’ van die vakgebied voorkom?

    Directory of Open Access Journals (Sweden)

    Johanna G. Ferreira

    2012-03-01

    Full Text Available In hierdie artikel word die wysiging van die skoolvak van ‘biologie’ na ‘lewenswetenskappe’ bespreek, asook die gepaardgaande en verwagte implikasies van die verandering. Die vraag word gestel of die beoogde wysiging wel noemenswaardig is en of dit enigsins ‘n verskil aan die dalende belangstelling in die lewenswetenskappe op tersiêre vlak sal maak. Die wysigings in die nuwe kurrikula verhoog die relevansie van die vakinhoud vir leerders en vir die gemeenskap, maar sekere kwessies kry nie aandag nie. Voorstelle word gemaak om die kurrikulum te wysig en onderrigmetodes aan te pas om die nodige vaardighede by leerders te vestig.

  14. enkele fasette van die problematiek van die akademikus by die skryf

    African Journals Online (AJOL)

    Om verskeie redes het dit van die allergrootste belong geword dot 'n his- tories korrekte, wetenskaplike weerga- we van bogenoemde gebeure opge- teken moet word. Die sluier, in sommige gevalle am logiese redes toegepas, moes eenvoudig gelig word am gebeure wat die gewone man op stroot in Suid-Afrika dikwels ...

  15. Die Defects and Die Corrections in Metal Extrusion

    Directory of Open Access Journals (Sweden)

    Sayyad Zahid Qamar

    2018-05-01

    Full Text Available Extrusion is a very popular and multi-faceted manufacturing process. A large number of products for the automotive, aerospace, and construction sectors are produced through aluminum extrusion. Many defects in the extruded products occur because of the conditions of the dies and tooling. The problems in dies can be due to material issues, design and manufacturing, or severe usage. They can be avoided by maintaining the billet quality, by controlling the extrusion process parameters, and through routine maintenance. Die problems that occur on a day-to-day basis are mostly repairable and are rectified through various types of die correction operations. These defects and repair operations have not been reported in detail in the published literature. The current paper presents an in-depth description of repairable die defects and related die correction operations in metal extrusion. All major die defects are defined and classified, and their causes, preventive measures, and die correction operations are described. A brief frequency-based statistical study of die defects is also carried out to identify the most frequent die corrections. This work can be of direct benefit to plant engineers and operators and to researchers and academics in the field of metal extrusion.

  16. Die hermeneutiek van gereformeerde kerkreg

    Directory of Open Access Journals (Sweden)

    Andries le Roux du Plooy

    2012-10-01

    Full Text Available Die artikel het op die belangrikheid en noodsaaklikheid van ‘n hermeneutiek vir die gereformeerde kerkreg gefokus. Die kerkregtelike dokument wat besonderlik ter sake was, is die kerkorde van die Gereformeerde kerke in Suid-Afrika, met sy besondere band met die Dordtse kerkorde van 1618 en 1619. Agtereenvolgens is aandag gegee aan die volgende aspekte soos (1 die eiesoortige aard van ‘n kerkorde as ‘n teologiese dokument en teks, in onderskeiding van regsdokumente; (2 die aard van die hermeneutiek van kerkreg; (3 enkele teorieë oor die interpretasie of uitleg van tekste, veral regstekste en (4 normatiewe vooronderstellings en reëls vir die interpretasie en verstaan van die teks en artikels van die kerkorde asook besluite van kerklike vergaderinge. Die gevolgtrekking was dat weinig indringende navorsing gedoen is oor die saak van hermeneutiek vir kerkreg, hoewel dit noodsaaklik is. Duidelike hermeneutiese reëls is gesuggereer en verduidelik, wat sou kon meehelp dat kerke en kerklike vergaderinge die artikels van die kerkorde asook besluite en reglemente wat daarop berus het, kan interpreteer en toepas. The hermeneutics of reformed church polity. The article focused on the importance and urgency of a design for reformed hermeneutics on church polity. The Church Order referred to in the article is the Church Order of the Reformed Churches in South Africa, which are closely related to the Church Order of Dordt of 1618 and 1619. The following aspects received attention namely (1  the unique character of a Church Order, in comparison to and distinguished from legal documents and statutes; (2 the character and nature of hermeneutics of church polity; (3 theories of interpretation in the common law tradition and their relevance to church polity and (4 normative presuppositions and marks for the interpretation and understanding of the text and articles of the Church Order, as well as the resolutions of church assemblies. It was found that

  17. A comparison of HDR brachytherapy and IMRT techniques for dose escalation in prostate cancer: A radiobiological modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Fatyga, M.; Williamson, J. F.; Dogan, N.; Todor, D.; Siebers, J. V.; George, R.; Barani, I.; Hagan, M. [Department of Radiation Oncology, Virginia Commonwealth University Medical Center, 401 College Street, Richmond, Virginia 23298 (United States)

    2009-09-15

    A course of one to three large fractions of high dose rate (HDR) interstitial brachytherapy is an attractive alternative to intensity modulated radiation therapy (IMRT) for delivering boost doses to the prostate in combination with additional external beam irradiation for intermediate risk disease. The purpose of this work is to quantitatively compare single-fraction HDR boosts to biologically equivalent fractionated IMRT boosts, assuming idealized image guided delivery (igIMRT) and conventional delivery (cIMRT). For nine prostate patients, both seven-field IMRT and HDR boosts were planned. The linear-quadratic model was used to compute biologically equivalent dose prescriptions. The cIMRT plan was evaluated as a static plan and with simulated random and setup errors. The authors conclude that HDR delivery produces a therapeutic ratio which is significantly better than the conventional IMRT and comparable to or better than the igIMRT delivery. For the HDR, the rectal gBEUD analysis is strongly influenced by high dose DVH tails. A saturation BED, beyond which no further injury can occur, must be assumed. Modeling of organ motion uncertainties yields mean outcomes similar to static plan outcomes.

  18. A novel GATA3 nonsense mutation in a newly diagnosed adult patient of hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome.

    Science.gov (United States)

    Nanba, Kazutaka; Usui, Takeshi; Nakamura, Michikazu; Toyota, Yuko; Hirota, Keisho; Tamanaha, Tamiko; Kawashima, Sachiko-Tsukamoto; Nakao, Kanako; Yuno, Akiko; Tagami, Tetsuya; Naruse, Mitsuhide; Shimatsu, Akira

    2013-01-01

    Hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder caused by a GATA3 gene mutation. Here we report a novel mutation of GATA3 in a patient diagnosed with HDR syndrome at the age of 58 with extensive intracranial calcification. A 58-year-old Japanese man showed severe hypocalcemia and marked calcification in the basal ganglia, cerebellum, deep white matter, and gray-white junction on computed tomography (CT). The serum intact parathyroid hormone level was relatively low against low serum calcium concentration. The patient had been diagnosed with bilateral sensorineural deafness in childhood and had a family history of hearing disorders. Imaging studies revealed no renal anomalies. The patient was diagnosed with HDR syndrome, and genetic testing was performed. Genetic analysis of GATA3 showed a novel nonsense mutation at codon 198 (S198X) in exon 3. The S198X mutation leads to a loss of two zinc finger deoxyribonucleic acid (DNA) binding domains and is considered to be responsible for HDR syndrome. We identified a novel nonsense mutation of GATA3 in an adult patient with HDR syndrome who showed extensive intracranial calcification.

  19. Die verband tussen lokus van beheer en die werks prestasie van swart bemarkers in die lewensversekeringsbedryf

    Directory of Open Access Journals (Sweden)

    E. L. Coetzer

    1997-06-01

    Full Text Available The relationship between locus of control and the work performance of black marketers in the life assurance industry. The aim of the study was to establish the relationship between locus of control and the work performance of black marketers in the life assurance industry. These constructs were selected by virtue of the lack of empirical research regarding the assumed relationship between them. The Locus of Control Scale of Schepers (1995 was used for measuring locus of control. Work performance was measured by the commission earned per month by the marketer, the number of policies generated by the marketer, as well as the percentage of lapsed policies. The relevant measurements were obtained in respect of a sample of 149 black marketing personnel. The results indicated a modest but statistically significant relationship between external locus of control and the work performance of black marketers. Opsomming Die doel van die studie was om die verband tussen lokus van beheer en die werksprestasie van swart bemarkers in die lewensversekeringsbedryf te bepaal. Hierdie konstrukte is gekies op grond van die gebrek aan empiriese navorsing rakende die veronderstelde verband tussen genoemde konstrukte. Die Lokus van Beheer-vraelys van Schepers (1995 is in die meting van lokus van beheer gebruik. Werksprestasie is aan die hand van kommissie per maand verdien, aantal polisse gegenereer deur 'n bemarker en die persentasie vervalde polisse, gemeet. Die tersaaklike metinge is verkry ten opsigte van 'n steekproef van 149 swart bemarkers. Die resultate toon 'n klein, dog statisties beduidende verband tussen eksterne lokus van beheer en die werksprestasie van swart bemarkers in die lewensversekeringsbedryf.

  20. Is die ortodoksie se verstaan van die sondeval belemmerend vir die gesprek tussen teologie en natuurwetenskap?

    Directory of Open Access Journals (Sweden)

    Johan Buitendag

    2012-11-01

    Full Text Available In hierdie artikel is betoog dat die Gereformeerde Ortodoksie se begrip van die sondeval ’n  belemmering  was  vir  die  gesprek  tussen  teologie  en  natuurwetenskap.  Die  rede hiervoor was dat dit ten eerste ’n bepaalde verstaan van liniêre tyd nahou en ten tweede dat dit ’n bonatuurlike ingryp veronderstel het. Albei hierdie aspekte het die debat onnodig problematiseer. Die argument is ontwikkel deur eerstens die probleem te definieer, gevolg deur ’n uiteensetting van die standpunte van Augustinus en Calvyn onderskeidelik oor die sondeval. As ’n heuristiese sleutel is die konsepte van infralapsarisme en supralapsarisme aangewend om die tema te ontleed. Die artikel is afgesluit met die oortuiging dat die imago Dei ’n beliggaamde menslike persoon is wat biologies in die geskiedenis in terme van selfbewussyn en morele verantwoordelikheid ontluik het. Is the Orthodoxy’s notion of the Fall inhibitory for the dialogue between theology and science? In this article it was argued that the Reformed Orthodoxy’s interpretation of the Fall had become an impediment in the dialogue between theology and science. The reason was that it assumed firstly a specific understanding of linear time and secondly a metaphysical intervention. Both events were unnecessarily problematising the debate. The argument was deployed by stating the problem, followed by an exposition of the views of Augustine and Calvin on the Fall. As a heuristic key, the concepts of infralapsarism and supralapsarism were applied respectively to analyse the topic. The article concluded with the conviction that the imago Dei is an embodied human person that had biologically emerged in history as a center of self-awareness, and moral responsibility.

  1. Sedimentêre omgewings van die Inhaca-eilandstelsel met spesiale verwysing na die petrografiese en geochemiese eienskappe van die sedimente spesiale verwysing na die petrografiese en geochemiese eienskappe van die sedimente

    Directory of Open Access Journals (Sweden)

    Marieke Peché

    2011-09-01

    Full Text Available Die Inhaca-eilandstelsel is geleë langs die suidooskus van Mosambiek. Die oostekant van die stelsel grens aan die Indiese Oseaan en die westekant aan die Baai van Maputo. Hierdie eilandstelsel bestaan uit Inhaca- en Portugese eiland, asook ’n groep sandbanke wat van die noordlike punt van Inhaca na Portugese eiland strek. Die doel van hierdie studie is om die verskillende moderne en oer-sedimentêre omgewings op die eilandstelsel te identifiseer en te beskryf, die invloed van getye en golfaksie op die moderne sedimentêre omgewing vas te stel en die geochemiese en petrografiese samestelling van die geologiese eenhede te bepaal.

  2. Die vangnet van die woord: forensies-linguistiese getuienis in 'n ...

    African Journals Online (AJOL)

    Een van die redes daarvoor is waarskynlik die gepaardgaande sleurwerk verbonde aan die verwerking van die betrokke taaldata — iets wat egter deur die onlangse meteoriese vooruitgang in tegnologiese tegnieke op die agtergrond geskuif is en nuwe moontlikhede na vore laat kom het. In die lig van die kompleksiteit van ...

  3. het om die Woord van God aan die gemeente te bedien. A. D. P ont ...

    African Journals Online (AJOL)

    Test

    Sizoo vertel met die vlotheid van die ervare skrywer en die ver antwoordelikheid van die wetenskaplike ... Maar in stiptelike trou aan die feitelikheid, verlaat die skrywer hom uitsluitlik op die outentieke bronne om ... de leser; in sy rykdom van gegewens en wetenskaplike betroubaarheid kan dit met vrug gelees word deur die ...

  4. Die invloed van herbivorie en vuur op die oorlewing van sekere meerjarige kruide langs die Sabierivier, Kruger Nasionale Park

    Directory of Open Access Journals (Sweden)

    H. Myburgh

    2012-03-01

    Full Text Available Die groot vloede wat in die jaar 2000 in die Kruger Nasionale Park plaasgevind het, het dierivieroewerplantegroei versteur. Dit het die geleentheid gebied om heinings op te rig langsdie Sabierivier om herbivore uit sekere gebiede uit te sluit en sodoende die herstel van die rivieroewerekosisteme te monitor.

  5. Die heelal en sy onstaan (II

    Directory of Open Access Journals (Sweden)

    D. J. Van Rooy

    1952-03-01

    Full Text Available Ons kennis en wetenskap van die hemelliggame word volkome bepaal deur die lig wat ons van hulle ontvang, d.w.s. as ons die feite wat die Bybel daaromtrent meedeel, buite rekening laat.

  6. Versoening tussen leerders: Is parallelmediumskole die antwoord op die rassismeprobleem?

    OpenAIRE

    Du Plessis, Elize; Marais, Petro

    2017-01-01

    Die Suid-Afrikaanse Grondwet stel dit duidelik dat enige vorm van diskriminasie nie toegelaat mag word nie. In ons skole beteken dit dat elke leerder ʼn reg het op goeie opvoeding en ʼn veilige skoolomgewing. Die fokus van hierdie navorsing is gerig op bestaande parallelmediumskole. Die uiteindelike vraagstuk is dus hoe multikulturele onderwys bevorder word en hoe rassisme aangespreek kan word? As teoretiese raamwerk is Kohlsberg se kognitiewe ontwikkelingsbenadering en Whitehouse se univerele ...

  7. Die ontmaskering van die bose: Eksegetiese perspektiewe op ...

    African Journals Online (AJOL)

    p1243322

    2 Yarbro Collins (1983) bied tans nog die beste agtergrond vir 'n besinning oor geweld in ..... John's grammatical howlers are intentionally designed to alert listerners ..... 26 In die Nuwe Testament word Paul se snydende opmerking teenoor die Korintiërs as ..... rnt g0r`m nh8 ldfhrs`}m du sg}u fg}u + n2sh d/m sg>}} e`ql`jdh.

  8. Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

    Science.gov (United States)

    Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

    2015-10-01

    Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

  9. Die pastorale sielkundige as diakonale pastor

    Directory of Open Access Journals (Sweden)

    A. J. Smuts

    1985-08-01

    Full Text Available In die bedieningspatroon van die Ned. Geref. Kerk het die pastorale sielkundige die afgelope aantal jare steeds meer op die voorgrond begin tree. Hy is egter 'n problematiese figuur, wie se identiteit van meer as een kant onder bespreking is. In ander lande, selfs in die VSA waar die kerk veel gebruik maak van die sielkunde, is dit moeilik om 'n presiese parallel vir hom te vind. Sowel binne as buite die kerk word hy deur sommige bevraagteken. Daarom is dit noodsaaklik om vanuit die teologie te kyk na die werk wat hy doen.

  10. On-line conformal HDR dose escalation trial in prostate cancer

    International Nuclear Information System (INIS)

    Martinez, Alvaro; Stromberg, Jannifer; Edmundson, Gregory; Gustafson, Gary; Vicini, Frank; Brabbins, Donald

    1996-01-01

    Purpose: To improve treatment results on prostatic adenocarcinoma, we began the first prospective Phase I/II dose-escalating clinical trial of conformal brachytherapy (CB) and concurrent external beam irradiation. Methods and Materials: Fifty-four patients with T2b-T3c prostatic adenocarcinoma received 172 transperineal conformal high-dose rate (HDR) boost implants. All patients received concomitant external beam pelvic irradiation. Dose escalation of the three HDR fractions were: 5.5 Gy (18 patients), 6 Gy (15 patients), and 6.5 Gy (21 patients). The urethra, anterior rectal wall, and prostate boundaries were identified individually and outlined at 5 mm intervals from the base to the apex of the gland. The CB using real-time ultrasound guidance with interactive online isodose distributions was performed on an outpatient basis. As needles were placed into the prostate, corrections for prostate displacement were recorded and the isodose distributions were recalculated to represent the new relationship between the needles, prostate, and normal structures. Results: Craniocaudal motion of the gland ranged from 0.5-2.0 cm (mean=1.0 cm), whereas lateral displacement was 0.1-0.4 cm. With the interactive online planning system, organ motion was immediately detected, accounted for, and corrected prior to each HDR treatment. The rectal dose has ranged from 45 to 87%, and the urethral dose from 97 to 112% of the prostate dose. Negative prostatic biopsies at 18 months were seen in (30(32)) patients. Biochemical (PSA <1.5 ng/ml) control at 36 months is is 89%. It is significant that operator dependence has been completely removed because the interactive online planning system uniformly guides the physicians. Conclusions: With ultrasound guidance and the interactive online dosimetry system, organ motion is insignificant because it can be corrected during the procedure. Common pitfalls of brachytherapy, including operator dependence and difficulty with reproducibility, have been

  11. SU-E-T-149: Brachytherapy Patient Specific Quality Assurance for a HDR Vaginal Cylinder Case

    Energy Technology Data Exchange (ETDEWEB)

    Barbiere, J; Napoli, J; Ndlovu, A [Hackensack Univ Medical Center, Hackensack, NJ (United States)

    2015-06-15

    Purpose: Commonly Ir-192 HDR treatment planning system commissioning is only based on a single absolute measurement of source activity supplemented by tabulated parameters for multiple factors without independent verification that the planned distribution corresponds to the actual delivered dose. The purpose on this work is to present a methodology using Gafchromic film with a statistically valid calibration curve that can be used to validate clinical HDR vaginal cylinder cases by comparing the calculated plan dose distribution in a plane with the corresponding measured planar dose. Methods: A vaginal cylinder plan was created with Oncentra treatment planning system. The 3D dose matrix was exported to a Varian Eclipse work station for convenient extraction of a 2D coronal dose plane corresponding to the film position. The plan was delivered with a sheet of Gafchromic EBT3 film positioned 1mm from the catheter using an Ir-192 Nucletron HDR source. The film was then digitized with an Epson 10000 XL color scanner. Film analysis is performed with MatLab imaging toolbox. A density to dose calibration curve was created using TG43 formalism for a single dwell position exposure at over 100 points for statistical accuracy. The plan and measured film dose planes were registered using a known dwell position relative to four film marks. The plan delivered 500 cGy to points 2 cm from the sources. Results: The distance to agreement of the 500 cGy isodose between the plan and film measurement laterally was 0.5 mm but can be as much as 1.5 mm superior and inferior. The difference between the computed plan dose and film measurement was calculated per pixel. The greatest errors up to 50 cGy are near the apex. Conclusion: The methodology presented will be useful to implement more comprehensive quality assurance to verify patient-specific dose distributions.

  12. SU-E-T-169: Characterization of Pacemaker/ICD Dose in SAVI HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kalavagunta, C; Lasio, G; Yi, B; Zhou, J; Lin, M [Univ. of Maryland School Of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose: It is important to estimate dose to pacemaker (PM)/Implantable Cardioverter Defibrillator (ICD) before undertaking Accelerated Partial Breast Treatment using High Dose Rate (HDR) brachytherapy. Kim et al. have reported HDR PM/ICD dose using a single-source balloon applicator. To the authors knowledge, there have so far not been any published PM/ICD dosimetry literature for the Strut Adjusted Volume Implant (SAVI, Cianna Medical, Aliso Viejo, CA). This study aims to fill this gap by generating a dose look up table (LUT) to predict maximum dose to the PM/ICD in SAVI HDR brachytherapy. Methods: CT scans for 3D dosimetric planning were acquired for four SAVI applicators (6−1-mini, 6−1, 8−1 and 10−1) expanded to their maximum diameter in air. The CT datasets were imported into the Elekta Oncentra TPS for planning and each applicator was digitized in a multiplanar reconstruction window. A dose of 340 cGy was prescribed to the surface of a 1 cm expansion of the SAVI applicator cavity. Cartesian coordinates of the digitized applicator were determined in the treatment leading to the generation of a dose distribution and corresponding distance-dose prediction look up table (LUT) for distances from 2 to 15 cm (6-mini) and 2 to 20 cm (10–1).The deviation between the LUT doses and the dose to the cardiac device in a clinical case was evaluated. Results: Distance-dose look up table were compared to clinical SAVI plan and the discrepancy between the max dose predicted by the LUT and the clinical plan was found to be in the range (−0.44%, 0.74%) of the prescription dose. Conclusion: The distance-dose look up tables for SAVI applicators can be used to estimate the maximum dose to the ICD/PM, with a potential usefulness for quick assessment of dose to the cardiac device prior to applicator placement.

  13. Palliative interstitial HDR brachytherapy for recurrent rectal cancer. Implantation techniques and results

    International Nuclear Information System (INIS)

    Kolotas, C.; Roeddiger, S.; Martin, T.; Tselis, N.; Baltas, D.; Zamboglou, N.; Strassmann, G.; Aebersold, D.M.

    2003-01-01

    Purpose: To report the methods and clinical results of CT-based interstitial high-dose-rate (HDR) brachytherapy procedures for the palliative treatment of recurrent rectal cancer. Patients and Methods: A total of 44 brachytherapy implants were performed in 38 patients. CT-guided catheter implants were performed in 34 patients under local anesthesia and sedation, and four patients were implanted intraoperatively. Of 40 CT-guided implants, 20 were done using metallic needles introduced via the sacrum and 20 were transperineal implants of plastic tubes in the presacral region. Postimplant CT scans were used for three-dimensional (3-D) conformal brachytherapy planning. Patients implanted with metallic needles were given a single fraction of 10-15 Gy using HDR 192 Ir, and those who received transperineal implants of plastic catheters were given fractionated brachytherapy, 5 Gy twice daily to a total dose of 30-40 Gy. The median tumor volume was 225 cm 3 with a range of 41-2,103 cm 3 . Results: After a median follow-up of 23.4 months, a total of 13/38 patients were alive. The median postbrachytherapy survival was 15 months with 18 of the 25 deaths due to distant metastases. Tumor response was as follows: 6/38 partial remission, 28/38 stable disease, and 4/38 local progression. A planning target volume (PTV) coverage > 85% was achieved in 42/44 implants. The treatment was well tolerated, and no acute complications were observed. One patient developed a fistula after 8 months. Pain relief was recorded in 34 patients (89.5%), and the median duration of this palliative effect was 5 months with a range of 1-13 months. Conclusions: Interstitial HDR brachytherapy is a valuable tool for the delivery of high doses and achieves effective palliation in recurrent rectal carcinoma. (orig.)

  14. Palliative interstitial HDR brachytherapy for recurrent rectal cancer. Implantation techniques and results

    Energy Technology Data Exchange (ETDEWEB)

    Kolotas, C. [Dept. of Radiation Oncology, Offenbach Hospital, Offenbach (Germany); Dept. of Radio-Oncology, Univ. of Bern, Inselspital, Bern (Switzerland); Roeddiger, S.; Martin, T.; Tselis, N.; Baltas, D.; Zamboglou, N. [Dept. of Radiation Oncology, Offenbach Hospital, Offenbach (Germany); Strassmann, G. [Dept. of Radiotherapy, Univ. Hospital, Philipps Univ., Marburg (Germany); Aebersold, D.M. [Dept. of Radio-Oncology, Univ. of Bern, Inselspital, Bern (Switzerland)

    2003-07-01

    Purpose: To report the methods and clinical results of CT-based interstitial high-dose-rate (HDR) brachytherapy procedures for the palliative treatment of recurrent rectal cancer. Patients and Methods: A total of 44 brachytherapy implants were performed in 38 patients. CT-guided catheter implants were performed in 34 patients under local anesthesia and sedation, and four patients were implanted intraoperatively. Of 40 CT-guided implants, 20 were done using metallic needles introduced via the sacrum and 20 were transperineal implants of plastic tubes in the presacral region. Postimplant CT scans were used for three-dimensional (3-D) conformal brachytherapy planning. Patients implanted with metallic needles were given a single fraction of 10-15 Gy using HDR {sup 192}Ir, and those who received transperineal implants of plastic catheters were given fractionated brachytherapy, 5 Gy twice daily to a total dose of 30-40 Gy. The median tumor volume was 225 cm{sup 3} with a range of 41-2,103 cm{sup 3}. Results: After a median follow-up of 23.4 months, a total of 13/38 patients were alive. The median postbrachytherapy survival was 15 months with 18 of the 25 deaths due to distant metastases. Tumor response was as follows: 6/38 partial remission, 28/38 stable disease, and 4/38 local progression. A planning target volume (PTV) coverage > 85% was achieved in 42/44 implants. The treatment was well tolerated, and no acute complications were observed. One patient developed a fistula after 8 months. Pain relief was recorded in 34 patients (89.5%), and the median duration of this palliative effect was 5 months with a range of 1-13 months. Conclusions: Interstitial HDR brachytherapy is a valuable tool for the delivery of high doses and achieves effective palliation in recurrent rectal carcinoma. (orig.)

  15. Implementation of microsource high dose rate (mHDR) brachytherapy in developing countries

    International Nuclear Information System (INIS)

    2001-11-01

    Brachytherapy using remote afterloading of a single high dose rate 192 Ir microsource was developed in the 1970s. After its introduction to clinics, this system has spread rapidly among developed Member States and has become a highly desirable modality in cancer treatment. This technique is now gradually being introduced to the developing Member States. The 192 Ir sources are produced with a high specific activity. This results in a high dose rate (HDR) to the tumour and shorter treatment times. The high specific activity simultaneously results in a much smaller source (so-called micro source, around I mm in diameter) which may be easily inserted into tissue through a thin delivery tube, the so-called interstitial treatment, as well as easily inserted into body cavities, the so-called intracavitary or endoluminal treatment. Another advantage is the ability to change dwell time (the time a source remains in one position) of the stepping source which allows dose distribution to match the target volume more closely. The purpose of this TECDOC is to advise radiation oncologists, medical physicists and hospital administrators in hospitals which are planning to introduce 192 Ir microsource HDR (mHDR) remote afterloading systems. The document supplements IAEA-TECDOC-1040, Design and Implementation of a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects, and will facilitate implementation of this new brachytherapy technology, especially in developing countries. The operation of the system, 'how to use the system', is not within the scope of this document. This TECDOC is based on the recommendations of an Advisory Group meeting held in Vienna in April 1999

  16. Westinghouse-GOTHIC distributed parameter modelling for HDR test E11.2

    International Nuclear Information System (INIS)

    Narula, J.S.; Woodcock, J.

    1994-01-01

    The Westinghouse-GOTHIC (WGOTHIC) code is a sophisticated mathematical computer code designed specifically for the thermal hydraulic analysis of nuclear power plant containment and auxiliary buildings. The code is capable of sophisticated flow analysis via the solution of mass, momentum, and energy conservation equations. Westinghouse has investigated the use of subdivided noding to model the flow patterns of hydrogen following its release into a containment atmosphere. For the investigation, several simple models were constructed to represent a scale similar to the German HDR containment. The calculational models were simplified to test the basic capability of the plume modeling methods to predict stratification while minimizing the number of parameters. A large empty volume was modeled, with the same volume and height as HDR. A scenario was selected that would be expected to stably stratify, and the effects of noding on the prediction of stratification was studied. A single phase hot gas was injected into the volume at a height similar to that of HDR test E11.2, and there were no heat sinks modeled. Helium was released into the calculational models, and the resulting flow patterns were judged relative to the expected results. For each model, only the number of subdivisions within the containment volume was varied. The results of the investigation of noding schemes has provided evidence of the capability of subdivided (distributed parameter) noding. The results also showed that highly inaccurate flow patterns could be obtained by using an insufficient number of subdivided nodes. This presents a significant challenge to the containment analyst, who must weigh the benefits of increased noding with the penalties the noding may incur on computational efficiency. Clearly, however, an incorrect noding choice may yield erroneous results even if great care has been taken in modeling accurately all other characteristics of containments. (author). 9 refs., 9 figs

  17. SU-F-T-63: Dosimetric Relevance of the Valencia and Leipzig HDR Applicators Plastic Cap

    Energy Technology Data Exchange (ETDEWEB)

    Granero, D [ERESA-Hospital General Universitario, Valencia (Spain); Candela-Juan, C [National Dosimetry Centre (CND), Valencia (Spain); Vijande, J; Ballester, F [University of Valencia, Burjassot (Spain); Perez-Calatayud, J [Hospital La Fe, Valencia (Spain); Jacob, D; Mourtada, F [Helen F. Graham Cancer Center, Christiana Care Health System, Newark, DE (United States)

    2016-06-15

    Purpose: Utilization of HDR brachytherapy treatment of skin lesions using collimated applicators, such as the Valencia or Leipzig is increasing. These applicators are made of cup-shaped tungsten material in order to focalize the radiation into the lesion and to protect nearby tissues. These applicators have an attachable plastic cap that removes secondary electrons generated in the applicator and flattens the treatment surface. The purpose of this study is to examine the dosimetric impact of this cap, and the effect if the cap is not placed during the HDR fraction delivery. Methods: Monte Carlo simulations have been done using the code Geant4 for the Valencia and Leipzig applicators. Dose rate distributions have been obtained for the applicators with and without the plastic cap. An experimental study using EBT3 radiochromic film has been realized in order to verify the Monte Carlo results. Results: The Monte Carlo simulations show that absorbed dose in the first millimeter of skin can increase up to 180% for the Valencia applicator if the plastic cap is absent and up to 1500% for the Leipzig applicators. At deeper distances the increase of dose is smaller being about 10–15%. Conclusion: Important differences have been found if the plastic cap of the applicators is absent in the treatment producing an overdosage in the skin. The user should have a checklist to remind him check always before HDR fraction delivery to insure the plastic cap is placed on the applicator. This work was supported in part by Generalitat Valenciana under Project PROMETEOII/2013/010, by the Spanish Government under Project No. FIS2013-42156, and by a research agreement with Elekta Brachytherapy, Veenendaal, The Netherlands.

  18. Digilanid C by die behandeling van hartlyers

    NARCIS (Netherlands)

    Snyman, Hendrik Willem

    1942-01-01

    In die voorafgaande word 'n literatuur studie oor die ontwikkeling en huidige stand van die chemie en farmakologie van die Digitalis purpurea en Digitalis lanata gegee, waarin spesiaal gelet word op die chemiese samestelling en farmakologiese aktiwiteit van die Digitalis lanata glikoside. Daarna

  19. HISTORIESE OORSIG VAN DIE ONTSTAAN EN ONTWIKKELING ...

    African Journals Online (AJOL)

    In 1933 belas Rykskanselier. Hitler vir. Goering, Minister van Lugvaart, in die geheim met die skepping van die Luftwaffe. Die basis in Rusland is gesluit en toekomstige vlieeniers is nou in die geheim na Italie waar hulle elke aspek van moderne oorlog- voering oefen en die Blitzkrieg-gedagte, deur op ondersteuning van 'n.

  20. EUNUG IN DIE ANTIEKE NABYE OOSTE

    African Journals Online (AJOL)

    rang. In Assiries beteken die woord “hoof-eunug”. Soos reeds vermeld (by 2), vorm die eunug 'n belangrike deel van die Assiriese burokrasie. Dokumente dui aan ... rang in die Babiloniese weermag, en so 'n amptenaar het saam met die rabsag ..... baie laat, in die inter-testamentêre periode, gebruik is vir 'n gekastreerde.

  1. Salvage prostate HDR brachytherapy combined with interstitial hyperthermia for local recurrence after radiation therapy failure

    Energy Technology Data Exchange (ETDEWEB)

    Kukielka, A.M.; Hetnal, M.; Dabrowski, T.; Walasek, T.; Brandys, P.; Reinfuss, M. [Centre of Oncology, M. Sklodowska - Curie Institute, Krakow Branch, Department of Radiotherapy, Krakow (Poland); Nahajowski, D.; Kudzia, R.; Dybek, D. [Centre of Oncology, M. Sklodowska - Curie Institute, Krakow Branch, Department of Medical Physics, Department of Radiotherapy, Krakow (Poland)

    2014-02-15

    The aim of the present retrospective study is to evaluate toxicity and early clinical outcomes of interstitial hyperthermia (IHT) combined with high-dose rate (HDR) brachytherapy as a salvage treatment in patients with biopsy-confirmed local recurrence of prostate cancer after previous external beam radiotherapy. Between September 2008 and March 2013, 25 patients with local recurrence of previously irradiated prostate cancer were treated. The main eligibility criteria for salvage prostate HDR brachytherapy combined with interstitial hyperthermia were biopsy confirmed local recurrence and absence of nodal and distant metastases. All patients were treated with a dose of 30 Gy in 3 fractions at 21-day intervals. We performed 62 hyperthermia procedures out of 75 planned (83 %). The aim of the hyperthermia treatment was to heat the prostate to 41-43 C for 60 min. Toxicity for the organs of the genitourinary system and rectum was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE, v. 4.03). Determination of subsequent biochemical failure was based on the Phoenix definition (nadir + 2 ng/ml). The median age was 71 years (range 62-83 years), the median initial PSA level was 16.3 ng/ml (range 6.37-64 ng/ml), and the median salvage PSA level was 2.8 ng/ml (1.044-25.346 ng/ml). The median follow-up was 13 months (range 4-48 months). The combination of HDR brachytherapy and IHT was well tolerated. The most frequent complications were nocturia, weak urine stream, urinary frequency, hematuria, and urgency. Grade 2 rectal hemorrhage was observed in 1 patient. No grade 3 or higher complications were observed. The 2-year Kaplan-Meier estimate of biochemical control after salvage treatment was 74 %. The PSA in 20 patients decreased below the presalvage level, while 11 patients achieved a PSA nadir < 0.5 ng/ml. All patients are still alive. Of the 7 patients who experienced biochemical failure, bone metastases were found in 2 patients. IHT in combination

  2. Is there any place for LDR brachytherapy for head and neck carcinomas in HDR era?

    Science.gov (United States)

    Fijuth, Jacek

    2009-03-01

    In Poland, the classical LDR brachytherapy for head and neck carcinomas with Ir-192 wires or hairpins has completely disappeared some time ago after 30 years of successful clinical use. Can this technique be fully and safely replaced by HDR or PDR application? This option seems attractive because of new possibilities of 3D reconstruction and computer real-time treatment planning and optimization. However, in my opinion, long time is needed to get a clinical and scientific experience that has been accumulated for decades with the use of LDR technique.

  3. Speedup of optimization-based approach to local backlight dimming of HDR displays

    DEFF Research Database (Denmark)

    Burini, Nino; Nadernejad, Ehsan; Korhonen, Jari

    2012-01-01

    Local backlight dimming in Liquid Crystal Displays (LCD) is a technique for reducing power consumption and simultaneously increasing contrast ratio to provide a High Dynamic Range (HDR) image reproduction. Several backlight dimming algorithms exist with focus on reducing power consumption, while...... other algorithms aim at enhancing contrast, with power savings as a side effect. In our earlier work, we have modeled backlight dimming as a linear programming problem, where the target is to minimize the cost function measuring the distance between ideal and actual output. In this paper, we propose...

  4. Die Transition zur pflegenden Tochter

    Directory of Open Access Journals (Sweden)

    Dagmar Dräger

    2004-11-01

    Full Text Available Das Buch aus der Reihe „Studien zur Gesundheits- und Pflegewissenschaft“ beschreibt den theoretischen Hintergrund, das methodische Vorgehen und die Ergebnisse einer biografischen Untersuchung, die sich dem Übergang von der Tochter zur pflegenden Tochter widmete. Grundlage der Publikation ist die Dissertation (2002 der Autorin. Mit der Berücksichtigung biographischer und familiärer Hintergründe wird eine neue Perspektive in der Forschung zu pflegenden Angehörigen eingenommen.

  5. Maintaining Low Voiding Solder Die Attach for Power Die While Minimizing Die Tilt

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Randy; Peterson, Kenneth A.

    2015-10-01

    This paper addresses work to minimize voiding and die tilt in solder attachment of a large power die, measuring 9.0 mm X 6.5 mm X 0.1 mm (0.354” x 0.256” x 0.004”), to a heat spreader. As demands for larger high power die continue, minimizing voiding and die tilt is of interest for improved die functionality, yield, manufacturability, and reliability. High-power die generate considerable heat, which is important to dissipate effectively through control of voiding under high thermal load areas of the die while maintaining a consistent bondline (minimizing die tilt). Voiding was measured using acoustic imaging and die tilt was measured using two different optical measurement systems. 80Au-20Sn solder reflow was achieved using a batch vacuum solder system with optimized fixturing. Minimizing die tilt proved to be the more difficult of the two product requirements to meet. Process development variables included tooling, weight and solder preform thickness.

  6. Neurokognitiewe integrasie en die leerproses

    Directory of Open Access Journals (Sweden)

    Du Preez, Johan J.

    1991-12-01

    Full Text Available The purpose of this article, "Neuro-cognitive integration and the learning process'; is to find principles and strategies for the development of brain potential and the optimal integration of subject matter. Eight neuro-cognitive systems are identified and their importance to the integration of subject matter is emphasized. These systems are cortical energy, coding, planning and controlling, as well as the verbal sequential, non-verbal holistic, physical-motor, social effective and the subconscious. The relevant principles and strategies can serve as basis for mainstream and special education, guidance as well as psychotherapy. Die doe! met hierdie artikel is om beginsels en strategiee te vind om breinpotensiaal te ontsluit en leerstof optimaal te integreer. Aan die hand van 'n neurokognitiewe model word 'n aantal beginsels en strategiee bespreek en die verband met die leerproses word aangetoon. Agt neurokognitiewe sisteme is gei'dentifiseer en die belangrike rot wat dit speel ten opsigte van die integrasie van leerstof word beklemtoon. Genoemde sisteme sluit die volgende in: kortikale energie, kodering, beplanning en kontrolering, asook die verbaal-sekwensiele, nieverbaal-holistiese, fisiek-motoriese, sosio-affektiewe en die subbewuste. Genoemde beginsels en strategiee kan oak dien as grondslag vir hoofstroomonderwys, spesialiseringsonderwys, voorligting sowel as psigoterapie.

  7. MO-C-17A-11: A Segmentation and Point Matching Enhanced Deformable Image Registration Method for Dose Accumulation Between HDR CT Images

    International Nuclear Information System (INIS)

    Zhen, X; Chen, H; Zhou, L; Yan, H; Jiang, S; Jia, X; Gu, X; Mell, L; Yashar, C; Cervino, L

    2014-01-01

    Purpose: To propose and validate a novel and accurate deformable image registration (DIR) scheme to facilitate dose accumulation among treatment fractions of high-dose-rate (HDR) gynecological brachytherapy. Method: We have developed a method to adapt DIR algorithms to gynecologic anatomies with HDR applicators by incorporating a segmentation step and a point-matching step into an existing DIR framework. In the segmentation step, random walks algorithm is used to accurately segment and remove the applicator region (AR) in the HDR CT image. A semi-automatic seed point generation approach is developed to obtain the incremented foreground and background point sets to feed the random walks algorithm. In the subsequent point-matching step, a feature-based thin-plate spline-robust point matching (TPS-RPM) algorithm is employed for AR surface point matching. With the resulting mapping, a DVF characteristic of the deformation between the two AR surfaces is generated by B-spline approximation, which serves as the initial DVF for the following Demons DIR between the two AR-free HDR CT images. Finally, the calculated DVF via Demons combined with the initial one serve as the final DVF to map doses between HDR fractions. Results: The segmentation and registration accuracy are quantitatively assessed by nine clinical HDR cases from three gynecological cancer patients. The quantitative results as well as the visual inspection of the DIR indicate that our proposed method can suppress the interference of the applicator with the DIR algorithm, and accurately register HDR CT images as well as deform and add interfractional HDR doses. Conclusions: We have developed a novel and robust DIR scheme that can perform registration between HDR gynecological CT images and yield accurate registration results. This new DIR scheme has potential for accurate interfractional HDR dose accumulation. This work is supported in part by the National Natural ScienceFoundation of China (no 30970866 and no

  8. Experimental work and know-how transfer in the framework of the individual project 'Earthquake investigations on the HDR reactor'

    International Nuclear Information System (INIS)

    Corvin, P.; Metz, K.

    1976-03-01

    In the framework of investigations to determine the earthquake resistance of nuclear power plant, carried out by the Applied Nucleonics Company on the HDR reactor in Grosswelzheim/Main, theoretical fundamentals and experimental test procedures in the sense of know-how transfer were elaborated. This enables the corresponding German institutions to carry out similar investigations on their own. In addition ANC carried out safety control measures during the investigations in order to prevent structural damage to the HDR reactor and neighbouring buildings. (orig.) 891 HP [de

  9. Evaluation of radiation doses on critical organs in the treatment of cancer of the cervix using HDR-brachytherapy

    International Nuclear Information System (INIS)

    Soares, Taciana; Jansem, Teresa

    2000-01-01

    High dose-rate (HDR) brachytherapy is one type of treatment of the cervix carcinoma. During the planning for this therapy, especial attention is given to proximal normal organs such as bladder and rectum. In fact, due to their radiosensibility and localization, bladder and rectum are considered as critical organs. In this work we have studied the influence of the positioning of patient legs in the dose delivered to these critical organs in the treatment of cancer of the cervix using HDR-brachytherapy. (author)

  10. Numerical optimization of die geometry in open die forging

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

    2013-01-01

    This paper deals with numerical optimization of open die forging of large metallic ingots made by casting implying risk of defects, e.g. central pores. Different material hardening properties and die geometries are combined in order to investigate, which geometry gives rise to maximum closure...

  11. die geskiedenis van die saw gedenkteken te fort klapperkop militere ...

    African Journals Online (AJOL)

    As gevolg van enige optrede, op enige plek, te enige tyd, deur enige vyand van die RSA of deur enige terroris(te), insurgent(e) of ander persoon of persone wat die RSA en sy volkere kwaadgesind is. h. Binne twee jaar (vyfhondred-en-dertig dae) nadat hy/sy met 'n ongeskiktheids- pensioen uit diens getree het agv siekte,.

  12. Die adversatiewe stelsel van bewyslewering en die beste belang ...

    African Journals Online (AJOL)

    MJM Venter

    weeg. Hierdie vraag word teen die agtergrond daarvan beoordeel dat veral dispute ..... restructuring family into the highly polarized positions of court-based dispute resolution.16. Talle alternatiewe om tekortkominge in die adversatiewe proses te ..... De Jong M "Mediation and Other Appropriate Forms of Alternative Dispute.

  13. Die teologiese debat: Die waarde of betekenis daarvan

    African Journals Online (AJOL)

    Ego vero hoc libro non contuli sed asservi et assero, ac penes nullum vo- lo esse iudicium, sed omnibus suadeo, ut praestent obsequium. (M Luther, De servo arbitrio, 1525). 1. INLEIDING. In ons dae is dit hoe mode om oor alles debat te voer. Een van die towerwoorde van ons tyd, veral op die politiek-staatkundige terrein, ...

  14. Die konteks vir die keuse van geriefsvoedsel van bepaalde ...

    African Journals Online (AJOL)

    Seugnet

    70. Die konteks vir die keuse van geriefsvoedsel van bepaalde beroepsvroue *. Martha Kok en Priscilla Botha. ABSTRACT. The purpose of this research is to understand and describe the context in which career women choose, purchase and use convenience food (CF). A person is rarely isolated from or unaffected by.

  15. Die vlugtige taal van vergeet: Die metafoor by Breyten Breytenbach ...

    African Journals Online (AJOL)

    From his first book of poetry, die ysterkoei moet sweet (“the iron cow must sweat”, 1964), till his most recent one, die windvanger (“the windcatcher”, 2007), metaphor has been a central means towards the creation of meaning for Breytenbach. This article will investigate the use of metaphor particularly in this recent book.

  16. Pylstertmotte (Lepidoptera: Sphingidae van die Nasionale Krugerwildtuin

    Directory of Open Access Journals (Sweden)

    M. A. van den Berg

    1975-07-01

    Full Text Available 'n Totaal van 42 spesies van pylstertmotte is in die Nasionale Krugerwildtuin versamel. Die bekendste hiervan is die patatrusper (Herse convolvuli (L en die dood-skedelmot (Acherontia atropos (L. Die volgende spesies wat versamel is, se voorkoms is nog nie voorheen vir die Republiek van Suid-Afrika aangemeld nie nl. Pemba flavillacea (Walk., Praedora plagiata (R. &J., Leptoclanis basalis (Walk., Polyptychus calcareus (R. &J., Polyptychus compar (R. &J., Nephele aequivalens (Walk., Nephele peneus (Cram., Hippotion roseipennis (Butler en Xenosphingia jansei (Jord.. Die verspreiding van Oligographa juniperi (Bsd. wat langs die kusgebiede van Natal en die Oos-Kaap aangetrefword, is op verskeie plekke in die Krugerwildtuin versamel.

  17. Statues Also Die

    Directory of Open Access Journals (Sweden)

    Pierre-Philippe Fraiture

    2016-10-01

    Full Text Available “African thinking,” “African thought,” and “African philosophy.” These phrases are often used indiscriminately to refer to intellectual activities in and/or about Africa. This large field, which sits at the crossroads between analytic philosophy, continental thought, political philosophy and even linguistics is apparently limitless in its ability to submit the object “Africa” to a multiplicity of disciplinary approaches. This absence of limits has far-reaching historical origins. Indeed it needs to be understood as a legacy of the period leading to African independence and to the context in which African philosophy emerged not so much as a discipline as a point of departure to think colonial strictures and the constraints of colonial modes of thinking. That the first (self-appointed exponents of African philosophy were Westerners speaks volumes. Placide Tempels but also some of his predecessors such as Paul Radin (Primitive Man as Philosopher, 1927 and Vernon Brelsford (Primitive Philosophy, 1935 were the first scholars to envisage this extension of philosophy into the realm of the African “primitive.” The material explored in this article – Statues Also Die (Marker, Resnais, and Cloquet, Bantu Philosophy (Tempels, The Cultural Unity of Negro Africa (Cheikh Anta Diop, and It For Others (Duncan Campbell - resonates with this initial gesture but also with the ambition on part of African philosophers such as VY Mudimbe to challenge the limits of a discipline shaped by late colonialism and then subsequently recaptured by ethnophilosophers. Statues Also Die is thus used here as a text to appraise the limitations of African philosophy at an early stage.  The term “stage,” however, is purely arbitrary and the work of African philosophers has since the 1950s often been absorbed by an effort to retrieve African philosophizing practices before, or away from, the colonial matrix. This activity has gained momentum and has been

  18. Die faktore gemeenskaplik aan die selfondersoekvraelys van Holland en die nuwe Suid-Afrikaanse beroepsbelangstellingsvraelys

    Directory of Open Access Journals (Sweden)

    C. Swanevelder

    1992-06-01

    Full Text Available The factors common to the Self Directed Search of Holland (SDS and the new South African Vocational Interest Inventory (SAVII. The new South African Vocational Interest Inventory was locally developed with the purpose to create a single vocational interest inventory for all population groups in the RSA. In this study the common factors underlying the SDS and the SAVII were determined with the aid of interbattery factor analysis. The results indicate that there are six common factors underlying the two instruments for both the standard nine boys and girls, and that these factors agree with the six factors built into the SDS by Holland. Opsomming Die nuwe Suid-Afrikaanse Beroepsbelangstellingsvraelys (SABBV is plaaslik ontwikkel met die doel om 'n enkele beroepsbelangstellingsvraelys vir alle bevolkingsgroepe binne die RSA, daar te stel. In hierdie studie is daar ondersoek ingestel na die gemeenskaplike faktore onderliggend aan die SABBV en die Selfondersoekvraelys (SOV van Holland met behulp van 'n interbatteryfaktorontleding. Daar is bevind dat daar ses gemeenskaplike faktore onderliggend aan die twee instrumente is vir sowel standerd nege seuns as dogters, en dat hierdie faktore ooreenstem met die ses faktore wat deur Holland in die SOV ingebou is.

  19. Awareness of Dying Preface

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2015-12-01

    Full Text Available Recently The New York Times reported: “VERY ILL CHILDREN TOLD OF DISEASE; Leukemia Patients at N.I.H. Not Shielded From Truth. . . . A child should always be told the truth, even when he has an incurable disease such as leukemia, according to two researchers who interviewed 51 children hospitalized at the National Cancer Institute, Bethesda, Maryland, for treat¬ment of leukemia.” This kind of news item reflects the growing concern among researchers and public about matters which touch on morality as much as on the technical aspects of medi¬cine. The rapidly increasing proportion of elderly people in the American population presents a range of personal and social questions; not the least is how they view their newly won longevity (often including anticipated years of chronic disease as well as their attitudes toward death. In consequence, many geriatric specialists are beginning to study American attitudes toward death, while others, spurred on by what seems a sense-less prolonging of life within hospital walls by medical tech¬nology run wild, are raising questions about death and dying in American life.

  20. A multicentre ‘end to end’ dosimetry audit for cervix HDR brachytherapy treatment

    International Nuclear Information System (INIS)

    Palmer, Antony L.; Diez, Patricia; Gandon, Laura; Wynn-Jones, Andrea; Bownes, Peter; Lee, Chris; Aird, Edwin; Bidmead, Margaret; Lowe, Gerry; Bradley, David; Nisbet, Andrew

    2015-01-01

    Purpose: To undertake the first multicentre fully ‘end to end’ dosimetry audit for HDR cervix brachytherapy, comparing planned and delivered dose distributions around clinical treatment applicators, with review of local procedures. Materials and methods: A film-dosimetry audit was performed at 46 centres, including imaging, applicator reconstruction, treatment planning and delivery. Film dose maps were calculated using triple-channel dosimetry and compared to RTDose data from treatment planning systems. Deviations between plan and measurement were quantified at prescription Point A and using gamma analysis. Local procedures were also discussed. Results: The mean difference between planned and measured dose at Point A was −0.6% for plastic applicators and −3.0% for metal applicators, at standard uncertainty 3.0% (k = 1). Isodose distributions agreed within 1 mm over a dose range 2–16 Gy. Mean gamma passing rates exceeded 97% for plastic and metal applicators at 3% (local) 2 mm criteria. Two errors were found: one dose normalisation error and one applicator library misaligned with the imaged applicator. Suggestions for quality improvement were also made. Conclusions: The concept of ‘end to end’ dosimetry audit for HDR brachytherapy has been successfully implemented in a multicentre environment, providing evidence that a high level of accuracy in brachytherapy dosimetry can be achieved

  1. Verification of experimental modal modeling using HDR (Heissdampfreaktor) dynamic test data

    International Nuclear Information System (INIS)

    Srinivasan, M.G.; Kot, C.A.; Hsieh, B.J.

    1983-01-01

    Experimental modal modeling involves the determination of the modal parameters of the model of a structure from recorded input-output data from dynamic tests. Though commercial modal analysis algorithms are being widely used in many industries their ability to identify a set of reliable modal parameters of an as-built nuclear power plant structure has not been systematically verified. This paper describes the effort to verify MODAL-PLUS, a widely used modal analysis code, using recorded data from the dynamic tests performed on the reactor building of the Heissdampfreaktor, situated near Frankfurt, Federal Republic of Germany. In the series of dynamic tests on HDR in 1979, the reactor building was subjected to forced vibrations from different types and levels of dynamic excitations. Two sets of HDR containment building input-output data were chosen for MODAL-PLUS analyses. To reduce the influence of nonlinear behavior on the results, these sets were chosen so that the levels of excitation are relatively low and about the same in the two sets. The attempted verification was only partially successful in that only one modal model, with a limited range of validity, could be synthesized and in that the goodness of fit could be verified only in this limited range

  2. Quality control of the breast cancer treatments on Hdr brachytherapy with TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Torres H, F. [Universidad de Cordoba, Materials and Applied Physics Group, 230002 Monteria, Cordoba (Colombia); De la Espriella V, N. [Universidad de Cordoba, Grupo Avanzado de Materiales y Sistemas Complejos, 230002 Monteria, Cordoba (Colombia); Sanchez C, A., E-mail: franciscotorreshoyos@yahoo.com [Universidad de Cordoba, Departamento de Enfermeria, 230002 Monteria, Cordoba (Colombia)

    2014-07-01

    An anthropomorphic Phantom, a female trunk, was built with a natural bone structure and experimental material coated, glycerin and water-based material called JJT to build soft tissue equivalent to the muscle of human tissue, and a polymer (styrofoam) to build the lung as critical organ to simulate the treatment of breast cancer, with high dose rate brachytherapy (Hdr) and sources of Ir-192. The treatments were planned and calculated for the critical organ: Lung, and injury of 2 cm in diameter in breast with Micro Selectron Hdr system and the software Plato Brachytherapy V 14.1 of the Nucletron (Netherlands) which uses the standard protocol of radiotherapy for brachytherapy treatments. The dose experimentally measured with dosimeters TLD-100 LiF: Mg; Ti, which were previously calibrated, were placed in the same positions and bodies mentioned above, with less than 5% uncertainty. The reading dosimeters was carried out in a Harshaw TLD 4500. The results obtained for calculated treatments, using the standard simulator, and the experimental with TLD-100, show a high concordance, as they are on average a ± 1.1% making process becomes in a quality control of this type of treatments. (Author)

  3. Essential results of analyses accompanying the leak rate experiments E22 at HDR

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1997-01-01

    During phase III of the HDR Safety Programme (HDR: decommissioned overheated steam reactor in Karlstein, Germany), experiments were performed in test group E22 on small-bore austenitic straight piping and on pipe elbows and branches containing through-wall cracks. The main aim was the determination of crack opening and leak rate behaviour for the cracked components under almost operational pressure and temperature loading conditions, especially including transient bending moments. In addition to machined slits, naturally grown fatigue cracks were also considered to cover the leakage behaviour. The experiments were accompanied by calculations, mainly performed by GRS. The paper describes the most important aspects and the essential results of the calculations and analysis. The main outcome was that the crack opening and initiation of crack growth can be described with the finite element techniques applied with sufficient accuracy. However, the qualification of the leak rate models could not be completed successfully, and therefore more sophisticated experiments of this kind are needed. (orig.)

  4. Seismic tests at the HDR facility using explosives and solid propellant rockets

    International Nuclear Information System (INIS)

    Corvin, P.; Steinhilber, H.

    1981-01-01

    In blast tests the HDR reactor building and its mechanical equipment were subjected to earthquake-type excitations through the soil and the foundation. A series of six tests was carried out, two tests being made with HDR facility under operating conditions (BWR conditions, 285 0 C, 70 bar). The charges were placed in boreholes at a depth of 4 to 10 m and a distance of 16 to 25 m from the reactor building. The tests with solid propellant rockets were made in order to try a new excitation technique. The rockets used in these tests were of compact design and had a short combustion period (500 ms) at high constant thrust (100 kN per combustion chamber). These rockets were fixed to the concrete dome of the building in such a way that the thrust generated during the combustion of the propellant resulted in an impulsive load acting on the building. This type of excitation was selected with a view to investigating the global effects of the load case 'aircraft impact' on the building and the mechanical equipment. In the four tests made so far, up to four rockets were ignited simultaneously, so that the maximum impulse was 2 x 10 5 Ns. The excitation level can be markedly increased by adding further rockets. This excitation technique was characterised by excellent reproducibility of the load parameters. (orig./HP)

  5. Variability of Marker-Based Rectal Dose Evaluation in HDR Cervical Brachytherapy

    International Nuclear Information System (INIS)

    Wang Zhou; Jaggernauth, Wainwright; Malhotra, Harish K.; Podgorsak, Matthew B.

    2010-01-01

    In film-based intracavitary brachytherapy for cervical cancer, position of the rectal markers may not accurately represent the anterior rectal wall. This study was aimed at analyzing the variability of rectal dose estimation as a result of interfractional variation of marker placement. A cohort of five patients treated with multiple-fraction tandem and ovoid high-dose-rate (HDR) brachytherapy was studied. The cervical os point and the orientation of the applicators were matched among all fractional plans for each patient. Rectal points obtained from all fractions were then input into each clinical treated plan. New fractional rectal doses were obtained and a new cumulative rectal dose for each patient was calculated. The maximum interfractional variation of distances between rectal dose points and the closest source positions was 1.1 cm. The corresponding maximum variability of fractional rectal dose was 65.5%. The percentage difference in cumulative rectal dose estimation for each patient was 5.4%, 19.6%, 34.6%, 23.4%, and 13.9%, respectively. In conclusion, care should be taken when using rectal markers as reference points for estimating rectal dose in HDR cervical brachytherapy. The best estimate of true rectal dose for each fraction should be determined by the most anterior point among all fractions.

  6. Interactive, multi-modality image registrations for combined MRI/MRSI-planned HDR prostate brachytherapy

    Directory of Open Access Journals (Sweden)

    Galen Reed

    2011-03-01

    Full Text Available Purpose: This study presents the steps and criteria involved in the series of image registrations used clinically during the planning and dose delivery of focal high dose-rate (HDR brachytherapy of the prostate. Material and methods: Three imaging modalities – Magnetic Resonance Imaging (MRI, Magnetic Resonance Spectroscopic Imaging (MRSI, and Computed Tomography (CT – were used at different steps during the process. MRSI is used for identification of dominant intraprosatic lesions (DIL. A series of rigid and nonrigid transformations were applied to the data to correct for endorectal-coil-induced deformations and for alignment with the planning CT. Mutual information was calculated as a morphing metric. An inverse planning optimization algorithm was applied to boost dose to the DIL while providing protection to the urethra, penile bulb, rectum, and bladder. Six prostate cancer patients were treated using this protocol. Results: The morphing algorithm successfully modeled the probe-induced prostatic distortion. Mutual information calculated between the morphed images and images acquired without the endorectal probe showed a significant (p = 0.0071 increase to that calculated between the unmorphed images and images acquired without the endorectal probe. Both mutual information and visual inspection serve as effective diagnostics of image morphing. The entire procedure adds less than thirty minutes to the treatment planning. Conclusion: This work demonstrates the utility of image transformations and registrations to HDR brachytherapy of prostate cancer.

  7. Die Parlamentswahlen 2008 in Malaysia

    DEFF Research Database (Denmark)

    Reher, Stefanie; Knirsch, Thomas

    2008-01-01

    aus diversen Parteien bestehende Oppositionsbündnis erfuhr überraschend eine klare Stärkung. Während die aus der UMNO und 13 weiteren Koalitionären bestehende BN unter dem Motto „Sicherheit, Frieden, Wohlstand” für Premier Badawi warb, führten die Oppositionsparteien DAP, PAS und PRK – letztere unter...

  8. In diens van die Kompanjie

    African Journals Online (AJOL)

    was ook siektes WQl Jit onvoldoende of ondoel- treffende voeding, eentonige kos en ontoerei- kende geneesmiddels voortgespruit het, terwyl behoorlike versorging dikwels ontbreek he!. Doodsoorsake tydens die seereis het voartge- vloei uit ongelukke aan boord, beperkte ruimte vir die bemanning en geringe vars lug, ...

  9. Die Mythen von der Globalisierung

    DEFF Research Database (Denmark)

    Nell, Phillip; Schmitt, Jan; Decreton, Benoit

    2017-01-01

    Der Wissensstand über den Grad und die Art der Globalisierung ist viel niedriger als angenommen. Daraus entstehen Fehleinschätzungen.......Der Wissensstand über den Grad und die Art der Globalisierung ist viel niedriger als angenommen. Daraus entstehen Fehleinschätzungen....

  10. n hoofstuk in die (outo)biografie van die predikant (pastor?) 1 ...

    African Journals Online (AJOL)

    biografie van die dominee (pastor?), spreek om verskeie redes boekdele. Die gebruik van die onbepaalde lidwoord is eerstens 'n bevestiging dat die artikel slegs 'n verdere bydrae (hoofstuk) tot die bestaande en steeds voortgaande gesprek (boek) oor die biografie van die dominee is (Heitink 2001). Tweedens plaas ek ...

  11. die krag van simbole en rites in die liturgie 1. probleemstelling

    African Journals Online (AJOL)

    uitroepe vervang met die drie keer Kyrie eleison, die drie maal Christe eleison en die drie keer Kyrie eleison-uitroepe (Albrecht 1989:43). Op die lang duur het die uitroep dus heeltemal losgeraak van die gebede en het dit 'n selfstandige liturgiese element geword (Van Rongen. 1990:35). Die Reformasie met sy nadruk op ...

  12. Vanaf die Fermat-punte na die De Villiers-punte van ’n driehoek

    Directory of Open Access Journals (Sweden)

    Michael de Villiers

    2010-01-01

    Full Text Available Hierdie artikel beskryf die ontdekking van die sogenaamde De Villiers-punte van ’n driehoek die bewyse wat betrokke is, en trek die historiese oorsprong terug na die Fermat-punte van ’n driehoek, die swaartepunt van ’n driehoek, en ’n nuttige veralgemening van die Fermat-punte van ’n driehoek.

  13. Implementation of the technique of partial irradiation accelerated the breast with high doses (HDR) brachytherapy; Puesta en marcha de la tecnica de irradiacion parcial acelerada de la mama con braquterapia de alta tasa de dosis (HDR)

    Energy Technology Data Exchange (ETDEWEB)

    Molina Lopez, M. Y.; Pardo Perez, E.; Castro Novais, J.; Martinez Ortega, J.; Ruiz Maqueda, S.; Cerro Penalver, E. del

    2013-07-01

    The objective of this work is presents procedure carried out in our Centre for the implementation of the accelerated partial breast irradiation (APBI, accelerated partial-breast irradiation) with high-rate brachytherapy (HDR), using plastic tubes as applicators. Carried out measures, the evaluation of the dosimetric parameters analyzing and presenting the results. (Author)

  14. Montessori-skole: die ander kant

    Directory of Open Access Journals (Sweden)

    Monica Viljoen

    1995-03-01

    Full Text Available Na aanleiding van die artikel “Die invloed van die New Age-beweging op die onderwysagenda van die toekoms” deur Lien van Niekerk en Corinne Meier van die Departement Historiese Opvoedkunde van Unisa (vgl. Koers, 59 (1 1994:69-84 wil ek graag ’n ander sy van Montessori-skole onder die aandag van Koers lesers bring.

  15. Mediamonitering in die bestuur van korporatiewe beeld

    OpenAIRE

    2012-01-01

    M.Comm. Die waarde van hierdie ondersoek hou verband met die bemarking van 'n onderneming en die handhawing van 'n mededingende voordeel deur die projektering van 'n positiewe beeld (Anon., 1995a:92; Bateman & Zeithaml, 1993:75; Caminiti, 1992:50; Kotler & Armstrong, 1991:240). Hierdie aspek neem toe in belangrikheid soos wat die besigheidsmilieu in Suid-Afrika verander, veral wat betref die toetrede van buitelandse maatskappye tot die Suid-Afrikaanse mark.

  16. A study of optimization techniques in HDR brachytherapy for the prostate

    Science.gov (United States)

    Pokharel, Ghana Shyam

    Several studies carried out thus far are in favor of dose escalation to the prostate gland to have better local control of the disease. But optimal way of delivery of higher doses of radiation therapy to the prostate without hurting neighboring critical structures is still debatable. In this study, we proposed that real time high dose rate (HDR) brachytherapy with highly efficient and effective optimization could be an alternative means of precise delivery of such higher doses. This approach of delivery eliminates the critical issues such as treatment setup uncertainties and target localization as in external beam radiation therapy. Likewise, dosimetry in HDR brachytherapy is not influenced by organ edema and potential source migration as in permanent interstitial implants. Moreover, the recent report of radiobiological parameters further strengthen the argument of using hypofractionated HDR brachytherapy for the management of prostate cancer. Firstly, we studied the essential features and requirements of real time HDR brachytherapy treatment planning system. Automating catheter reconstruction with fast editing tools, fast yet accurate dose engine, robust and fast optimization and evaluation engine are some of the essential requirements for such procedures. Moreover, in most of the cases we performed, treatment plan optimization took significant amount of time of overall procedure. So, making treatment plan optimization automatic or semi-automatic with sufficient speed and accuracy was the goal of the remaining part of the project. Secondly, we studied the role of optimization function and constraints in overall quality of optimized plan. We have studied the gradient based deterministic algorithm with dose volume histogram (DVH) and more conventional variance based objective functions for optimization. In this optimization strategy, the relative weight of particular objective in aggregate objective function signifies its importance with respect to other objectives

  17. Filosofiese tendense in die wordinggeskiedenis van ons verstaan van die fisiese natuur

    Directory of Open Access Journals (Sweden)

    D. F. M. Strauss

    2006-09-01

    Full Text Available Die ontstaan van ’n lang tradisie van natuurwetenskaplike denke is in antieke Griekeland te vind – die bakermat van die Westerse beskawing en die bron van geartikuleerde rasionele besinning. Die vroegste fases van die Griekse kultuur het reeds geboorte geskenk aan ’n teoretiese nadenke oor die heelal. Die Pythagoreërs is veral bekend vir hul klem op die verklaringskrag van getalsverhoudinge. In hul tese dat “alles getal is” het hulle egter slegs rasionale getalle (breuke erken en gevolglik uiteindelik vasgeloop in die ontdekking van irrasionale getalle wat tot die geometrisering van die Griekse wiskunde gelei het en tegelyk die bedding gevorm het van waaruit ’n magtige tradisie van ruimte-metafisika gegroei het wat die hele middeleeuse tydperk omspan het. Die vermeende statiese syn is in die mees ekstreme geval – die skool van Parmenides en die argumente van Zeno teen veelheid en beweging – tot in die uiteindelike antinomiese konsekwensies daarvan deurdink. Dit was egter eers die vroeg-moderne tyd – die voorgangers en nakomelinge van Galilei – wat naas getal en ruimte ’n waardering ontwikkel het vir die verklaringskrag van beweging (vergelyk die klassieke meganistiese wêreldbeeld van die heelal as ’n meganisme van stofdeeltjies in beweging. Maar ook hierdie meganistiese reduksie (waardeur alle fisiese verskynsels herlei is tot die beweging van al of niegelade massapunte sou uiteindelik misluk omdat dit nie van die onomkeerbaarheid van fisiese prosesse rekenskap kon gee nie. Gevolglik beliggaam eers die fisika van die 20ste eeu ’n erkenning van die deurslaggewend-stempelende rol van energie-werking (dus van die fisiese aspek in die aard van stoflike dinge en prosesse. Die artikel word afgesluit met ’n vlugtige verduideliking van die implikasies van die voorafgaande argumentasie vir ’n benadering van die misterie van die bestaan van materie.

  18. Die identifisering van maatstawwe vir die navorsingsprestasie van akademici

    Directory of Open Access Journals (Sweden)

    H. A. Labuschagne

    1990-06-01

    Full Text Available Identification of criteria for academic research performance. At South African universities, the achievement of objectives is usually measured in terms of so-called "process criteria" (e.g. pass rates, instead of performance criteria which reflect the quality of academic personnel. Stimulated by the need to identify valid indices of research performance, as a component of academic performance, this study investigated the dimensionality of several criteria, identified from empirical and literature studies. It was found that various valid criteria could be represented by six constructs, viz.: the stature of the researcher as scientist; scientific contributions; enhancement of own profession; community development; participation in research projects; and giving advice to persons or institutions outside the university. Opsomming By Suid-Afrikaanse universiteite word doelwitbereiking gewoonlik aan die hand van sogenaamde "prosesmaat-stawwe" (bv. slaagsyfers in plaas van prestasiemaatstawwe wat die gehalte van akademiese personeel weerspieel, gemeet. Na aanleiding van 'n behoefte aan die identifisering van geldige rigtingwysers vir navorsingsprestasie as 'n komponent van akademiese prestasie, is daar ondersoek ingestel na die dimensionaliteit van verskillende maatstawwe wat vooraf deur middel van empiriese- en literatuurstudies geidentifiseer is. Daar is gevind dat verskeie geldige maatstawwe deur ses konstrukte verteenwoordig word, te wete: die statuur van die navorser as wetenskaplike, wetenskaplike bydraes, uitbouing van eie professie, gemeenskapsontwikkeling, deelname aan navorsingsprojekte en advieslewering aan persone of instellings buite die Universiteit.

  19. Die toepassing van die K3-model op die televisieteks Colour TV

    African Journals Online (AJOL)

    “OIL's approach to investigating the coloured market took place in the form of ethnographic research which ... communication strategies” (Botha 2010: 14). ... Op grond van die waarnemings, onderhoude en vraelyste het OIL tot die volgende ..... hold onto your nearest and dearest because this is going to be a kwaai mix bag.

  20. Pre- and post-calculations for crack opening and leak rate experiments on piping components within the HDR-program

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1991-01-01

    In this paper calculations to experiments on leak opening and leak rates of piping components are presented. The experiments are performed at the HDR-facility at Karlstein/Germany and up to now straight pipes and pipe branches were considered. Numerical and experimental results are compared. (author)

  1. Die kliniese kindersielkundige as diagnostikus1

    Directory of Open Access Journals (Sweden)

    D. J. W. Strümpfer

    1961-03-01

    Full Text Available Die benaming „Kliniese Kindersielkunde” is nog onbekend en gevolglik betreklik onbemind. Dit is in 1951 die eerste keer gebruik. Die werk van die Kliniese Kindersielkunde is egter so oud as die werk van die algemene Kliniese Sielkunde, waarvan die geskiedenis gewoonlik teruggevoer word tot die begin van sielkundige toetsing vroeg in die tagtigerjare. Tot ’n aansienlike mate is hierdie vroeë werk op kinders uitgevoer, bv. dié van Galton en later die van Binet en Simon. Witmer het in 1896 die eerste sielkundige kliniek geopen en het ook die term „Kliniese Sielkunde” ingevoer; die meerderheid van sy pasiënte was egter ook kinders. Tot voor die Tweede Wêreldoorlog was klinies-sielkundige werk hoofsaaklik op kinders toegespits. Sedertdien het die kliniese sielkundige tot ’n belangrike mate toegetree tot die gebied van die diagnose en terapie van psigiese afwykings by volwassenes, tot so ’n mate dat in die gedagtes en geskrifte van baie werkers die terrein van die Kliniese Sielkunde byna tot werk met volwassenes beperk word.

  2. James Henry Greathead en die Londense Moltrein

    Directory of Open Access Journals (Sweden)

    Laurence Wright

    2017-07-01

    Full Text Available Die artikel ondersoek die oorsprong en vroeë geskiedenis van die toestel genaamd die ‘Greathead Skild’, ‘n belangrike nuwigheid in Viktoriaanse ingenieurwetenskap, wat van deurslaggewende belang was in die konstruksie van die Londense Moltrein. Die doel is om die basis te ontleed waarop, baie jare later, ‘n Suid-Afrikaanse ingenieur wye openbare erkenning in die vorm van ‘n standbeeld vir die ‘ontwerp’ van die Skild geniet het. Uit die perspektief van kulturele studies beskou, hoe moet ons uitvinding verstaan, gegewe dat ander briljante ingenieurs ook betrokke was? Hierdie vraag word ontleed met die gebruik van die konsep ‘extelligence’ (Stewart and Cohen 1997, in samehang met ander kontemporêre en geskiedkundige weergawes, insluitend Greathead se eie rekord van sy prestasies in die verrigtinge van die Instituut van Siviele Ingenieurs en voorgelê in The City and South London Railway (1896, onder redaksie van James Forrest. Hierdie artikel is die eerste keer as referaat aangebied by die konferensie oor ‘Nuuthede en Innovasie in die Negentiende Eeu’ aan die Noordwes-Universiteit, Mei 2016.

  3. DIE NAAM “NEDERDUITSE GEREFORMEERDE KERK”

    African Journals Online (AJOL)

    P.J. Strauss. DIE NAAM “NEDERDUITSE. GEREFORMEERDE KERK”. ABSTRACT. An investigation into the name of the Dutch Reformed Church (DRC) reveals that it is a reformed church in the ... P.J. Strauss, Fakulteit Teologie, Universiteit van die Vrystaat, Suid‑Afrika. ..... Dit is so omdat die staat en sy howe die reg in die ...

  4. Abstraksie en veralgemening in die Wiskunde

    Directory of Open Access Journals (Sweden)

    B.C. Strydom

    1967-03-01

    Full Text Available Wanneer ek tot u spreek oor abstraksie en veralgemening in die Wiskunde, wil ek u aandag vestig op die belangrikheid daarvaan vir die Wiskunde, maar u terselfdertyd daarop wys dat die wiskundige hom nie langs hierdie weg heeltemal van die werklikheid kan losmaak nie.

  5. Die Dankesrede bei der Preisverleihung

    Directory of Open Access Journals (Sweden)

    Elenmari Pletikos Olof

    2012-12-01

    Full Text Available Festliche Preisverleihungen sind Gelegenheiten, bei denen von den Preisträgerneine kurze Rede erwartet wird. Obwohl die Dankesrede eine kleinere Randgattung innerhalb des epideiktischen Genres ist, steht sie im Mittelpunkt des Ereignisses. Rhetorikhandbücher geben zahlreiche Ratschläge, wie eine gute Festrede vorbereitet werden soll, um zu unterhalten, zu bewegen und zu belehren. Ziel dieser Untersuchung ist es festzustellen, welche Eigenschaften der Dankesrede die Zuhörer als erwünscht oder unerwünscht wahrnehmen und welche Charakteristika am meisten zur Qualität festlicher Dankesreden beitragen. Das Korpus der gesprochenen Texte bilden 30 Dankesreden anlässlich kroatischer Preisverleihungen in den Bereichen Schauspiel, Sport, Musik, Fernsehen, Literatur und Wirtschaft. Die Audio-Aufnahmen der Dankesreden wurden einer Gruppe von Hörern zur Bewertung in folgenden Kategorien vorgelegt: interessant, geistreich, hoher Sprachstil, feierlich, emotiv, persönlich, originell, bescheiden, vorbereitet und spontan. Zusätzlich wurde zu jeder Rede die offene Frage gestellt, was dem Zuhörer an der Rede gefallen oder nicht gefallen habe. Die Resultate der Perzeptionsanalye lassen erkennen, dass die Interessantheit einer Rede mit der Eigenschaft des Geistreichen, des Originellen, des Emotionalen und des Persönlichen in Verbindung gebracht wird und die Eigenschaft des Festlichen im Wesentlichen nur mit dem hohen Sprachstil und der Vorbereitetheit des Textes korreliert. Einige Eigenschaften können sowohl erwünscht als auch unerwünscht sein, z. B. Dialekt, Persönliches und Kürze. Die besten Dankesreden haben Eigenschaften, die im Grunde schwer miteinander zu verbinden sind: Einerseits soll der Text vorbereitet sein (hoher Stil, Wortwahl, Figuren, Originalität der Geschichte, Humor, andererseits wird bei der Ausführung Spontaneität (Aufrichtigkeit, Emotionalität, Persönlichkeit erwartet.

  6. Author: T Bekker DIE MOONTLIKE REGSHERVORMING VAN DIE ...

    African Journals Online (AJOL)

    RV

    So ver terug as die vroeë twintigste eeu het die Appèlhof in Cassiem v Standard. Bank of SA Ltd,1 .... 838; Capital Building Society v De Jager 1963 3 SA 381 (T); Smit v Walles 1985 2 SA 189 (T). 196-198. 18 ...... moeilik kon regverdig.97. Ons howe het tot op hede gehuiwer om 'n algemene plig van goeie trou ten aansien.

  7. Braquiterapia endoluminal HDR no tratamento de tumores primários ou recidivas na árvore traqueobrônquica Endoluminal high dose rate brachytherapy in the treatment of primary and recurrent bronchogenic tree malignancies

    Directory of Open Access Journals (Sweden)

    Maria Fortunato

    2009-03-01

    primários sintomáticos apresentam uma boa tolerância e um alívio sintomático associado a uma boa qualidade de vida. Apesar da reduzida amostra, os resultados demonstram as eventuais vantagens da BTE de HDR no tratamento paliativo/ curativo destes doentesIntroduction: Locally advanced tumours as the initial form of presentation of tumours in the bronchial tree are not a rare event. Bronchogenic recurrence is frequent in the natural history of some tumours. The choice of therapeutic options from the raft available depends on such variables as initial therapy, place of recurrence, symptoms and patient’s physical status. Aim: To demonstrate the advantages of endoluminal brachytherapy (EBT with high dose rate (HDR in primary and recurrent tumour of the bronchial tree. Material and methods: A retrospective study of seven patients (pts with primary tumours of the colon, trachea and lung. Tracheobronchial recurrence (trachea, two pts, bronchus, five pts occurred between March 2003 and September 2004. Patients under-went EBT with HDR for primary or recurrent therapy in association with external radiotherapy, laser therapy and chemotherapy with palliative or curative intention. EBT with HDR doses of 5 to 7 Gy in 2 to 4 fractions at 1 cm from the source axis were given. Treatment included endoluminal application of Ir192 with a French 6 catheter. Results: There was symptomatic relief related to reduction of tumour in six of the seven patients treated. In one of the six patients studied, there was progression of the local disease between the second and third fractions of the treatment (obstruction of the trachea. In a mean follow up of 17 (2-40 months between EBT and this study, three patients are alive, one has no evidence of disease while two have had bronchial recurrence, four patients have died, one after massive haemoptysis and three due to disease progression. Discussion and conclusions: Patients undergoing brachytherapy for symptomatic primary tumours or

  8. Balloon-based adjuvant radiotherapy in breast cancer: comparison between {sup 99m}Tc and HDR {sup 192}Ir

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Tarcisio Passos Ribeiro de; Lima, Carla Flavia de; Cuperschmid, Ethel Mizrahy, E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2016-03-15

    Objective: To perform a comparative dosimetric analysis, based on computer simulations, of temporary balloon implants with {sup 99m}Tc and balloon brachytherapy with high-dose-rate (HDR) {sup 192}Ir, as boosts to radiotherapy. We hypothesized that the two techniques would produce equivalent doses under pre-established conditions of activity and exposure time. Materials and methods: simulations of implants with {sup 99m}Tc-filled and HDR {sup 192}Ir-filled balloons were performed with the Siscodes/MCNP5, modeling in voxels a magnetic resonance imaging set related to a young female. Spatial dose rate distributions were determined. In the dosimetric analysis of the protocols, the exposure time and the level of activity required were specified. Results: the {sup 99m}Tc balloon presented a weighted dose rate in the tumor bed of 0.428 cGy.h{sup -1}.mCi{sup -1} and 0.190 cGyh{sup -1} at the balloon surface and at 8-10 mm from the surface, respectively, compared with 0.499 and 0.150 cGyh{sup -1}.mCi{sup -1}, respectively, for the HDR {sup 192}Ir balloon. An exposure time of 24 hours was required for the {sup 99m}Tc balloon to produce a boost of 10.14 Gy with 1.0 Ci, whereas only 24 minutes with 10.0 Ci segments were required for the HDR {sup 192}Ir balloon to produce a boost of 5.14 Gy at the same reference point, or 10.28 Gy in two 24-minutes fractions. Conclusion: temporary {sup 99m}Tc balloon implantation is an attractive option for adjuvant radiotherapy in breast cancer, because of its availability, economic viability, and similar dosimetry in comparison with the use of HDR {sup 192}Ir balloon implantation, which is the current standard in clinical practice. (author)

  9. Effect and toxicity of endoluminal high-dose-rate (HDR) brachytherapy in centrally located tumors of the upper respiratory tract

    International Nuclear Information System (INIS)

    Harms, W.; Wannenmacher, M.; Becker, H.; Herth, F.; Fritz, P.

    2000-01-01

    Aim: To assess effect an toxicity of high-dose-rate afterloading (HDR) alone or in combination with external beam radiotherapy (EBRT) in centrally located tumors of the upper respiratory tract. Patients and Methods: From 1987 to 1996, 55 patients were treated. Twenty-one patients (group A1: 17 non-small-cell lung cancer [NSCLC], A2: 4 metastases from other malignancies) were treated using HDR alone due to a relapse after external beam irradiation. In 34 previously untreated and inoperable patients (group B1: 27 NSCLC, B2: 7 metastases from other malignancies) HDR was given as a boost after EBRT (30 to 60 Gy, median 50). HDR was carried out with a 192 Ir source (370 GBq). The brachytherapy dose (group A: 5 to 27 Gy, median 20; B: 10 to 20 Gy, median 15) was prescribed to 1 cm distance from the source axis. A distanciable applicator was used in 39/55 patients. Results: In group A1, a response rate (CR, PR) of 53% (group B1: 77%) was reached. The median survival (Kaplan-Meier) was 5 months in group A1 (B1: 20 months). The 1-, 3- and 5-year local progression free survival rates (Kaplan-Meier) were 66% (15%), 52% (0%), and 37% (0%) in group B1 (group A1). Prognostic favorable factors in group B1 were a tumor diameter 70. Grade-1 or 2 toxicity (RTOG/EORTC) occurred in 0% in group A and in 6% in group B. We observed no Grad-3 or 4 toxicity. Complications caused by persistent or progressive local disease occurred in 3 patients in goup A (fatal hemorrhage, tracheomediastinal fistula, hemoptysis) and in 2 patients in group B (fatal hemorrhage, hemoptysis). Conclusions: HDR brachytherapy is an effective treatment with moderate side effects. In combination with external beam irradiation long-term remissions can be reached in one third of the patients. (orig.) [de

  10. Balloon-based adjuvant radiotherapy in breast cancer: comparison between 99mTc and HDR 192Ir

    Directory of Open Access Journals (Sweden)

    Tarcísio Passos Ribeiro de Campos

    2016-04-01

    Full Text Available Abstract Objective: To perform a comparative dosimetric analysis, based on computer simulations, of temporary balloon implants with 99mTc and balloon brachytherapy with high-dose-rate (HDR 192Ir, as boosts to radiotherapy. We hypothesized that the two techniques would produce equivalent doses under pre-established conditions of activity and exposure time. Materials and Methods: Simulations of implants with 99mTc-filled and HDR 192Ir-filled balloons were performed with the Siscodes/MCNP5, modeling in voxels a magnetic resonance imaging set related to a young female. Spatial dose rate distributions were determined. In the dosimetric analysis of the protocols, the exposure time and the level of activity required were specified. Results: The 99mTc balloon presented a weighted dose rate in the tumor bed of 0.428 cGy.h-1.mCi-1 and 0.190 cGyh-1.mCi-1 at the balloon surface and at 8-10 mm from the surface, respectively, compared with 0.499 and 0.150 cGyh-1.mCi-1, respectively, for the HDR 192Ir balloon. An exposure time of 24 hours was required for the 99mTc balloon to produce a boost of 10.14 Gy with 1.0 Ci, whereas only 24 minutes with 10.0 Ci segments were required for the HDR 192Ir balloon to produce a boost of 5.14 Gy at the same reference point, or 10.28 Gy in two 24-minutes fractions. Conclusion: Temporary 99mTc balloon implantation is an attractive option for adjuvant radiotherapy in breast cancer, because of its availability, economic viability, and similar dosimetry in comparison with the use of HDR 192Ir balloon implantation, which is the current standard in clinical practice.

  11. Quantenfische die Stringtheorie und die Suche nach Weltformel

    CERN Document Server

    Lüst, Dieter

    2011-01-01

    Lässt sich das Verhalten aller Dinge, von den kleinsten Teilchen bis zum Universum, einheitlich beschreiben? Der heißeste Kandidat für die Entwicklung einer Weltformel, die alle physikalischen Phänomene erklären kann, ist die Stringtheorie. Sollte sie sich als richtig erweisen, so würde das unser Verständnis über den Ursprung der Naturgesetze dramatisch verändern. Denn das von uns beobachtete Universum wäre dann vermutlich eine winzige Blase in einem viel größeren Gebilde, dem Multiversum. Um die Stringtheorie und die Idee des Multiversums plausibel zu machen, greift der international bekannte theoretische Physiker Dieter Lüst auf ein Modell zurück: das Leben von Fischen in einem Teich. Eines Tages gelingt es den Fischen, die kleinsten Teilchen zu identifizieren, aus denen alles im Fischteich besteht - eingeschlossen sie selbst. Sie nennen diese Urbausteine Quantenfische, da ihr Verhalten nahelegt, dass sie auch eine Art von Lebewesen sind. Doch der ersten folgt eine weitere Entdeckung der Fisch...

  12. Die rol van persoonlikheidstrekke in die weerstand teen stres

    Directory of Open Access Journals (Sweden)

    Sonja V. R. van Oudtshoorn

    1988-05-01

    Full Text Available The role of personality characteristics in resistance to stress: A study was conducted to establish whether certain personality characteristics contribute to resistance to stress. Rescue brigadesmen, performing dangerous rescue operations in the goldmining industry, served as basis for the study. The sample consisted of 63 current, 56 ex- and 50 non-brigadesmen. Results indicate that brigadesmen, on the basis of their personality structure, are better equipped to cope with stress. Scores on the 16PF show that they have a lower level of interpersonal anxiety (Factor Q4 and that they are more practical (Factor I, emotionally stable (Factor C, and conscientious (Factor G. These findings support existing knowledge of the 16PF. Opsomming Ten einde vas te stel ofdaar sekere persoonlikheidstrekke bestaan wat bydra tot weerstand teen stres, is 'n studie uitgevoer met reddingspanlede, wat lewensgevaarlike reddingsdiens in die goudmynbedryf verrig, as ondersoekgroep. Die streekproefhet uit 63 huidige, 56 oud-reddingspanlede en 50 amptenare, wat nog nooit aan die span behoort het nie, bestaan. Dit blyk dat reddingspanlede, op grond van hulle persoonlikheidstruktuur, beter toegerus is om stres te hanteer. Tellings op die 16PF toon dat hulle oor 'n laervlakvan interpersoonlike angs beskik, (Faktor Q4, dat hulle meer prakties (Faktor I, emosioneel stabiel (Faktor C en konsensieus is (Faktor G. Hierdie bevindinge sluit aan by die reeds bestaande kennis oor die 16PF.

  13. Dosimetric intercomparison of permanent Ho-166 seed's implants and HDR Ir-192 brachytherapy in breast cancer.

    Science.gov (United States)

    de Campos, Tarcisio Passos Ribeiro; Nogueira, Luciana Batista; Trindade, Bruno; Cuperschmid, Ethel Mizrahy

    2016-01-01

    To provide a comparative dosimetric analysis of permanent implants of Ho(166)-seeds and temporary HDR Ir(192)-brachytherapy through computational simulation. Brachytherapy with Ir(192)-HDR or LDR based on temporary wires or permanent radioactive seed implants can be used as dose reinforcement for breast radiation therapy. Permanent breast implants have not been a practical clinical routine; although, I(125) and Pd(103)-seeds have already been reported. Biodegradable Ho(166)-ceramic-seeds have been addressed recently. Simulations of implants of nine Ho(166)-seeds and equivalent with HDR Ir(192)-brachytherapy were elaborated in MCNP5, shaped in a computational multivoxel simulator which reproduced a female thorax phantom. Spatial dose rate distributions and dose-volume histograms were generated. Protocol's analysis involving exposure time, seed's activities and dose were performed. Permanent Ho(166)-seed implants presented a maximum dose rate per unit of contained activity (MDR) of 1.1601 μGy h(-1) Bq(-1); and, a normalized MDR in standard points (8 mm, equidistant to 03-seeds - SP1, 10 mm - SP2) of 1.0% (SP1) and 0.5% (SP2), respectively. Ir(192)-brachytherapy presented MDR of 4.3945 × 10(-3) μGy h(-1) Bq(-1); and, 30% (SP1), and 20% (SP2). Therefore, seed's implant activities of 333 MBq (Ho(166)) and 259 GBq (Ir(192)) produced prescribed doses of 58 Gy (SP1; 5d) and 56 Gy (SP1, 5 fractions, 6 min), respectively. Breast Ho(166)-implants of 37-111 MBq are attractive due to the high dose rate near 6-10 mm from seeds, equivalent to Ir(192)-brachytherapy of 259 GBq (3 fractions, 6 min) providing similar dose in standard points at a week; however, with spatial dose distribution better confined. The seed positioning can be adjusted for controlling the breast tumor, in stages I and II, in flat and deep tumors, without any breast volumetric limitation.

  14. Source position verification and dosimetry in HDR brachytherapy using an EPID

    International Nuclear Information System (INIS)

    Smith, R. L.; Taylor, M. L.; McDermott, L. N.; Franich, R. D.; Haworth, A.; Millar, J. L.

    2013-01-01

    Purpose: Accurate treatment delivery in high dose rate (HDR) brachytherapy requires correct source dwell positions and dwell times to be administered relative to each other and to the surrounding anatomy. Treatment delivery inaccuracies predominantly occur for two reasons: (i) anatomical movement or (ii) as a result of human errors that are usually related to incorrect implementation of the planned treatment. Electronic portal imaging devices (EPIDs) were originally developed for patient position verification in external beam radiotherapy and their application has been extended to provide dosimetric information. The authors have characterized the response of an EPID for use with an 192 Ir brachytherapy source to demonstrate its use as a verification device, providing both source position and dosimetric information.Methods: Characterization of the EPID response using an 192 Ir brachytherapy source included investigations of reproducibility, linearity with dose rate, photon energy dependence, and charge build-up effects associated with exposure time and image acquisition time. Source position resolution in three dimensions was determined. To illustrate treatment verification, a simple treatment plan was delivered to a phantom and the measured EPID dose distribution compared with the planned dose.Results: The mean absolute source position error in the plane parallel to the EPID, for dwells measured at 50, 100, and 150 mm source to detector distances (SDD), was determined to be 0.26 mm. The resolution of the z coordinate (perpendicular distance from detector plane) is SDD dependent with 95% confidence intervals of ±0.1, ±0.5, and ±2.0 mm at SDDs of 50, 100, and 150 mm, respectively. The response of the EPID is highly linear to dose rate. The EPID exhibits an over-response to low energy incident photons and this nonlinearity is incorporated into the dose calibration procedure. A distance (spectral) dependent dose rate calibration procedure has been developed. The

  15. Comparison of air-kerma strength determinations for HDR {sup 192}Ir sources

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Brian E.; Davis, Stephen D.; Schmidt, Cal R.; Micka, John A.; DeWerd, Larry A. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2011-12-15

    Purpose: To perform a comparison of the interim air-kerma strength standard for high dose rate (HDR) {sup 192}Ir brachytherapy sources maintained by University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) with measurements of the various source models using modified techniques from the literature. The current interim standard was established by Goetsch et al. in 1991 and has remained unchanged to date. Methods: The improved, laser-aligned seven-distance apparatus of University of Wisconsin Medical Radiation Research Center (UWMRRC) was used to perform air-kerma strength measurements of five different HDR {sup 192}Ir source models. The results of these measurements were compared with those from well chambers traceable to the original standard. Alternative methodologies for interpolating the {sup 192}Ir air-kerma calibration coefficient from the NIST air-kerma standards at {sup 137}Cs and 250 kVp x rays (M250) were investigated and intercompared. As part of the interpolation method comparison, the Monte Carlo code EGSnrc was used to calculate updated values of A{sub wall} for the Exradin A3 chamber used for air-kerma strength measurements. The effects of air attenuation and scatter, room scatter, as well as the solution method were investigated in detail. Results: The average measurements when using the inverse N{sub K} interpolation method for the Classic Nucletron, Nucletron microSelectron, VariSource VS2000, GammaMed Plus, and Flexisource were found to be 0.47%, -0.10%, -1.13%, -0.20%, and 0.89% different than the existing standard, respectively. A further investigation of the differences observed between the sources was performed using MCNP5 Monte Carlo simulations of each source model inside a full model of an HDR 1000 Plus well chamber. Conclusions: Although the differences between the source models were found to be statistically significant, the equally weighted average difference between the seven-distance measurements and the well

  16. Comparison of air-kerma strength determinations for HDR 192Ir sources

    International Nuclear Information System (INIS)

    Rasmussen, Brian E.; Davis, Stephen D.; Schmidt, Cal R.; Micka, John A.; DeWerd, Larry A.

    2011-01-01

    Purpose: To perform a comparison of the interim air-kerma strength standard for high dose rate (HDR) 192 Ir brachytherapy sources maintained by University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) with measurements of the various source models using modified techniques from the literature. The current interim standard was established by Goetsch et al. in 1991 and has remained unchanged to date. Methods: The improved, laser-aligned seven-distance apparatus of University of Wisconsin Medical Radiation Research Center (UWMRRC) was used to perform air-kerma strength measurements of five different HDR 192 Ir source models. The results of these measurements were compared with those from well chambers traceable to the original standard. Alternative methodologies for interpolating the 192 Ir air-kerma calibration coefficient from the NIST air-kerma standards at 137 Cs and 250 kVp x rays (M250) were investigated and intercompared. As part of the interpolation method comparison, the Monte Carlo code EGSnrc was used to calculate updated values of A wall for the Exradin A3 chamber used for air-kerma strength measurements. The effects of air attenuation and scatter, room scatter, as well as the solution method were investigated in detail. Results: The average measurements when using the inverse N K interpolation method for the Classic Nucletron, Nucletron microSelectron, VariSource VS2000, GammaMed Plus, and Flexisource were found to be 0.47%, -0.10%, -1.13%, -0.20%, and 0.89% different than the existing standard, respectively. A further investigation of the differences observed between the sources was performed using MCNP5 Monte Carlo simulations of each source model inside a full model of an HDR 1000 Plus well chamber. Conclusions: Although the differences between the source models were found to be statistically significant, the equally weighted average difference between the seven-distance measurements and the well chambers was 0.01%, confirming that

  17. Comparison of air-kerma strength determinations for HDR (192)Ir sources.

    Science.gov (United States)

    Rasmussen, Brian E; Davis, Stephen D; Schmidt, Cal R; Micka, John A; Dewerd, Larry A

    2011-12-01

    To perform a comparison of the interim air-kerma strength standard for high dose rate (HDR) (192)Ir brachytherapy sources maintained by the University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) with measurements of the various source models using modified techniques from the literature. The current interim standard was established by Goetsch et al. in 1991 and has remained unchanged to date. The improved, laser-aligned seven-distance apparatus of the University of Wisconsin Medical Radiation Research Center (UWMRRC) was used to perform air-kerma strength measurements of five different HDR (192)Ir source models. The results of these measurements were compared with those from well chambers traceable to the original standard. Alternative methodologies for interpolating the (192)Ir air-kerma calibration coefficient from the NIST air-kerma standards at (137)Cs and 250 kVp x rays (M250) were investigated and intercompared. As part of the interpolation method comparison, the Monte Carlo code EGSnrc was used to calculate updated values of A(wall) for the Exradin A3 chamber used for air-kerma strength measurements. The effects of air attenuation and scatter, room scatter, as well as the solution method were investigated in detail. The average measurements when using the inverse N(K) interpolation method for the Classic Nucletron, Nucletron microSelectron, VariSource VS2000, GammaMed Plus, and Flexisource were found to be 0.47%, -0.10%, -1.13%, -0.20%, and 0.89% different than the existing standard, respectively. A further investigation of the differences observed between the sources was performed using MCNP5 Monte Carlo simulations of each source model inside a full model of an HDR 1000 Plus well chamber. Although the differences between the source models were found to be statistically significant, the equally weighted average difference between the seven-distance measurements and the well chambers was 0.01%, confirming that it is not necessary to

  18. Nuwe patogene in die voedselbedryf

    Directory of Open Access Journals (Sweden)

    M. M. Ehlers

    1996-07-01

    Full Text Available ’n “Nuwe generasie” voedselpatogene het die afgelope jare hul verskyning gemaak en kan 'n ernstige gevaar vir die voedselbedryf inhou. Hierdie organismes is uiters aanpasbaar en bestaande voedselprosesseringstegnieke, veral die verkoeling van voedsel, is nie altyd volkome effektief om hul groei te voorkom nie. Clostridium botulinum tipe E, enterotoksigeniese Eschsrichia coli. Listeria monocytogenes en Aeromonas hydrophila is in staat om in voedsel by 5 °C te groei. Campylobacter jejuni en Brucella kan weer by 5 °C oorleef en 'n derde groep organismes, naamlik Salmonella, Staphylococcus aureus, Vibrio parahaemolyticus en Vibrio vulnificus kan by temperature tussen 5 °C en 12 °C groei en hul teenwoordigheid is ’n aanduiding dat die koueketting verbreek is.

  19. Die Last mit der Lust

    Directory of Open Access Journals (Sweden)

    Lutz Sauerteig

    2004-03-01

    Full Text Available Robert Jütte legt mit Lust ohne Last eine umfassende, allgemeinverständliche und spannend zu lesende Geschichte der Empfängnisverhütung von der Antike bis in die unmittelbare Gegenwart vor.

  20. pastorale begeleiding aan die persoon met dissosiatiewe ...

    African Journals Online (AJOL)

    psychological or pastoral by nature. Effective assistance to the person ... INLEIDING. Volgens die kriteria in die DSM-IV2 (Diagnostic and statistical manual of mental disorders, 4th edition) van die APA (American Psychiatric. Association 1995) ...

  1. The efficient ones; Die Leistungsfaehigen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2000-06-01

    The increase of output of a solar system where vacuum tube collectors replace flatbed collectors is difficult to calculate exactly. The formula for the calculation of efficiency is the basis of such calculations. Due to evacuation and better insulation the heat loss of vacuum tube collectors is smaller than that of flatbed collectors. This is also evident in the fact that the efficiency curve decreases less steeply as the temperature difference increases. Efficiency remains relatively high. Up to now vacuum tube collectors have been a niche product but more and more companies now sell these efficient collectors.(orig.). [German] Wie stark sich die Leistung der Solaranlage verbessert, wenn man Vakuumroehrenkollektoren (VRK) statt Flachkollektoren einsetzt, laesst sich nur schwer berechnen. Grundlage ist stets die Wirkungsgradformel. Aufgrund der Evakuierung und dadurch besseren Isolierung weisen die VRK deutlich geringere Waermeverluste auf als Flachkollektoren. Dies drueckt sich auch dadurch aus, dass die Wirkungsgradkurve mit wachsender Temperaturdifferenz {delta}{theta} deutlich flacher abfaellt. Der Wirkungsgrad bleibt relativ hoch. Als Hightech-Produkt hatte der Vakuumroehrenkollektor bisher eine typische Marktnische besetzt. Doch immer mehr Anbieter entscheiden sich fuer die Vermarktung dieser leistungsfaehigen Kollektoren. (orig.)

  2. Reparation of damaged forging dies

    Directory of Open Access Journals (Sweden)

    Vukić Lazić

    2015-03-01

    Full Text Available The forging dies are in exploitation exposed to elevated temperatures and variable impact loads, both compressive and shear. Steels for manufacturing of these tools must endure those loads while maintaining mechanical properties and being resistant to wear and thermal fatigue. For those reasons, the alloyed steels are used for making the forging dies, though they have less weldability, because alloying increases proneness to hardening. Any reparatory hard facing (HF of the damaged dies would require the specially adjusted technology to the particular piece. In this paper reparatory hard facing of dies used for forging pieces in the automobile industry is considered. Prior to reparatory hard facing of the real tools, numerous experimental hard facings on models were performed. All the model hard facings were done on the same steels which were used for production of the real forging dies. To define the optimal hard facing technology one needs to derive the optimal combination of the adequate heat treatment(s, to select the proper filler metals and the welding procedure. The established optimal HF technology was applied to real forging dies whose service life was further monitored in conditions of exploitation

  3. Uitdagings in die onderrig van evolusie in die lewenswetenskappeklaskamer

    Directory of Open Access Journals (Sweden)

    Josef J. de Beer

    2013-02-01

    Full Text Available In hierdie artikel skryf die outeurs oor navorsing wat hulle gedoen het oor onderwysers se siening van die onderrig van evolusie, wat in 2008 as ’n tema in lewenswetenskappe in Suid-Afrikaanse skole ingesluit is. Hierdie vernuwing in die kurrikulum is met gemengde reaksies begroet. Terwyl sommige onderwysers dit met entoesiasme onderrig, is baie gekant teen die onderrig van evolusie. Die artikel is gebaseer op ’n navorsingsprojek waarby 255 onderwysers betrek is. Vraelyste is gebruik om kwalitatiewe data, wat vir diskoers ontleed is, in te samel. Die diskoers van die onderwysers het getoon dat ’n groot getal van hulle nie hul onderrigopdrag kan versoen met hul geloof nie en konsepte oor evolusie as ‘feite’ verduidelik, maar seker maak dat evolusie as ’n teorie gediskrediteer word. Dit het verreikende implikasies vir sowel onderwyseropleiding as kurrikulumontwikkeling. Konseptuele veranderingsteorie word as ’n lens gebruik om na hierdie problematiek te kyk. Challenges in the teaching of evolution in the life sciences classroom. In this article the authors report on research that was conducted about teachers’ views on evolution, which was introduced as a theme in the school life sciences curriculum in 2008. This innovation in the curriculum has been met with mixed reactions. Whereas some teachers embrace this new theme, many teachers are opposed to the teaching of evolution. The article reports on an inquiry that was conducted amongst 255 teachers and in which survey questionnaires were used to collect qualitative data, which was analysed for its discourse. The discourse of the teachers shows that many of them cannot reconcile their religious faith with their teaching and that they may teach the ‘facts’ of evolution, but make sure that they discredit evolution as a theory. This raises serious concerns about teacher education and curriculum development. The authors examine these issues through the lens of conceptual change

  4. Experimental and theoretical investigations of soil-structure interaction effect at HDR-reactor-building

    International Nuclear Information System (INIS)

    Wassermann, K.

    1983-01-01

    Full-scale dynamic testing on intermediate and high levels was performed at the Heissdampfreaktor (HDR) in 1979. Various types of dynamic forces were applied and response of the reactor containment structure and internal components was measured. Precalculations of dynamic behaviour and response of the structure were made through different mathematical models for the structure and the underlying soil. Soil-Structure Interaction effects are investigated and different theoretical models are compared with experimental results. In each model, the soil is represented by springs attached to the structural model. Stiffnesses of springs are calculated by different finite-element idealizations and half-space approximations. Eigenfrequencies and damping values related to interaction effects (translation, rocking, torsion) are identified from test results. The comparisons of dynamic characteristic of the soil-structure system between precalculations and test results show good agreement in general. (orig.)

  5. SW England seismic monitoring for the HDR geothermal programme in Cornwall 1989 to September 1991

    International Nuclear Information System (INIS)

    Walker, A.B.

    1992-01-01

    The potential for earthquakes to be triggered by fluid injected into boreholes has been recognised for 25 years and natural earthquakes in Cornwall have been reported for over 250 years. As a result, the Geothermal Steering Committee advising the Hot Dry Rock project recommended that background seismic monitoring be undertaken around the HDR experimental site at Rosemanowes. A network of seismographs was established for this purpose by the British Geological Survey (BGS) in late 1980 and has been operated continuously through September 1991. The primary aim of the network has been to provide an independent, continuous assessment of all vibrational transients in order to discriminate between those caused by the Hot Dry Rock experiments and those of natural origin or from other man-made sources. In this respect, the work provides an insurance against claims that extraneous seismic activity is related to those experiments. (author)

  6. Structural safety of HDR reactor building during large scale vibration tests

    International Nuclear Information System (INIS)

    Stangenberg, F.; Zinn, R.

    1985-01-01

    In the second phase of the HDR investigations, a high shaker excitation of the building is planned using a large shaker which will be located on the operating floor and will be brought up to speed in a balanced condition and then unbalanced and decoupled from the drive system. With decreasing speed the shaker comes in resonance with the building frequencies and its energy is transferred to the building. In this paper the structural safety of the reactor building during the projected shaker tests is analysed. Dynamic response calculations with coupling between building and shaker by simultaneously integrating the equilibrium equations of both building and shaker are presented. The resulting building stresses, soil pressures etc. are compared with allowable values. (orig.)

  7. Comparison of leak opening and leak rate calculations to HDR experimental results

    International Nuclear Information System (INIS)

    Grebner, H.; Hoefler, A.; Hunger, H.

    1993-01-01

    During the last years a number of calculations of leak opening and leak rate for through cracks in piping components have been performed. Analyses are pre- or mostly post-calculations to experiments performed at the HDR facility under PWR operating conditions. Piping components under consideration were small diameter straight pipes with circumferential cracks, pipe bends with longitudinal or circumferential cracks and pipe branches with weldment cracks. The components were loaded by internal pressure and opening as well as closing bending moment. The finite element method and two-phase flow leak rate programs were used for the calculations. Results of the analyses are presented as J-integral values, crack opening displacements and areas and leak rates as well as comparisons to the experimental results

  8. Accurate assessment of the distortions produced by the transit dose in HDR brachytherapy

    International Nuclear Information System (INIS)

    Nani, E.K.; Kyere, A.W.K.; Tetteh, K.

    2001-01-01

    Current polynomial methods used in the modelling of the dose distributions in HDR brachytherapy have been reformulated to improve accuracy. An example is provided to show the effects of the transit dose on the output. The transit dose, which is neglected by current computer software for calculating doses, can result in significant dosimetric errors. These additional unrecognised doses imply over-dosing and distortions in the dose distributions within the irradiated volume. Assessment of dose to critical and radiosensitive organs is therefore inaccurate. These could increase late tissue complications as predicted by the Linear Quadratic Model. Our model works very well for straight catheters and is highly recommended for the evaluation of the transit dose around such catheters. (author)

  9. Heissdampfreaktor (HDR) steel-containment-vessel and floodwater-storage-tank structural-dynamics tests

    International Nuclear Information System (INIS)

    Arendts, J.G.

    1982-01-01

    Inertance (vibration) testing of two significant vessels at the Heissdampfreaktor (HDR) facility, located near Kahl, West Germany, was recently completed. Transfer functions were obtained for determination of the modal properties (frequencies, mode shapes and damping) of the vessels using two different test methods for comparative purposes. One of the vessels tested was the steel containment vessel (SCV). The SCV is approximately 180 feet high and 65 feet in diameter with a 1.2-inch wall thickness. The other vessel, called the floodwater storage tank (FWST), is a vertically standing vessel approximately 40 feet high and 10 feet in diameter with a 1/2-inch wall thickness. The FWST support skirt is square (in plan views) with its corners intersecting the ellipsoidal bottom head near the knuckle region

  10. Video Enhancement and Dynamic Range Control of HDR Sequences for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Giovanni Ramponi

    2007-01-01

    Full Text Available CMOS video cameras with high dynamic range (HDR output are particularly suitable for driving assistance applications, where lighting conditions can strongly vary, going from direct sunlight to dark areas in tunnels. However, common visualization devices can only handle a low dynamic range, and thus a dynamic range reduction is needed. Many algorithms have been proposed in the literature to reduce the dynamic range of still pictures. Anyway, extending the available methods to video is not straightforward, due to the peculiar nature of video data. We propose an algorithm for both reducing the dynamic range of video sequences and enhancing its appearance, thus improving visual quality and reducing temporal artifacts. We also provide an optimized version of our algorithm for a viable hardware implementation on an FPGA. The feasibility of this implementation is demonstrated by means of a case study.

  11. Computed versus measured response of HDR reactor building in large scale shaking tests

    International Nuclear Information System (INIS)

    Werkle, H.; Waas, G.

    1987-01-01

    The earthquake resistant design of NPP structures and their installations is commonly based on linear analysis methods. Nonlinear effects, which may occur during strong earthquakes, are approximately accounted for in the analysis by adjusting the structural damping values. Experimental investigations of nonlinear effects were performed with an extremely heavy shaker at the decommissioned HDR reactor building in West Germany. The tests were directed by KfK (Nuclear Research Center Karlsruhe, West Germany) and supported by several companies and institutes from West Germany, Switzerland and the USA. The objective was the dynamic repsonse behaviour of the structure, piping and components to strong earthquake-like shaking including nonlinear effects. This paper presents some results of safety analyses and measurements, which were performed prior and during the test series. It was intended to shake the building up to a level where only a marginal safety against global structural failure was left

  12. HDR Brachytherapy in the Management of High-Risk Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Susan Masson

    2012-01-01

    Full Text Available High-dose-rate (HDR brachytherapy is used with increasing frequency for the treatment of prostate cancer. It is a technique which allows delivery of large individual fractions to the prostate without exposing adjacent normal tissues to unacceptable toxicity. This approach is particularly favourable in prostate cancer where tumours are highly sensitive to dose escalation and to increases in radiotherapy fraction size, due to the unique radiobiological behaviour of prostate cancers in contrast with other malignancies. In this paper we discuss the rationale and the increasing body of clinical evidence for the use of this technique in patients with high-risk prostate cancer, where it is combined with external beam radiotherapy. We highlight practical aspects of delivering treatment and discuss toxicity and limitations, with particular reference to current practice in the United Kingdom.

  13. die kasteel••de goede hoop" (1921.1923): die verhaal van in ...

    African Journals Online (AJOL)

    3. TWEE. KOMITEE-VERGADERINGS. BESLUITE a. Doel en samestelling van die komitee. Op 12 Desember 1921 stuur die Sekretans yap Verdediging uitnodigings aan sekere amptelike instansies en ander behingstd1endes waarin hy die redes vir die wenslikheid van 'n komitee en die werksaamhede uitecnsit en die ge-.

  14. Chrístologie: Die historiese Jesus en die kerugmatiese Christus by ...

    African Journals Online (AJOL)

    dige Here van sy kerk. Die Christelike teologie en die kerk het dus nie 'n ander oprsprong as wat die Christologiese belydenis van die oer-Christendom het nie, naamlik die paasgebeure. Schmithals (1972b:77) wil kerk en teologie aanmoedig om hierdie oorsprong in gedagte te hou en om goed te besef dat die Christus-.

  15. PROF DR FELIX V. lATEGAN: Die Boer se Roer. Die Groot ...

    African Journals Online (AJOL)

    PROF DR FELIX V. lATEGAN: Die Boer se. Roer. Die Groot Geweerboek van Suid-. Afrika. Tafelberg. Uitgewers. Kaapstad, pp. 209, bibliografie, register. Sonder die Boer en sy roer is die geskiede:lis van ons land feitlik ondenkbc:wr en dit is clan ook vo/kome juis gesien dat die skrywer van hierdie baanbrekerswerk die ...

  16. Die Energiesicherheit Europas in Bezug auf Erdgas und die Auswirkungen einer Kartellbildung im Gassektor

    OpenAIRE

    Krämer, Luis-Martín

    2011-01-01

    Die Dissertation untersucht die aktuelle Sicherheit der europaeischen Erdgasversorgung. Sie beruecksichtigt zudem die moeglichen Auswirkungen einer Kartellbildung auf die europaeische Gasversorgungssicherheit. Die Arbeit besteht aus einer detaillierten empirischen Studie und darauf aufbauender Szenarioanalyse. Hierzu wird auf den Interdependenzansatz von Robert O. Keohane und Joseph Nye zurueckgegriffen. Zur Darstellung des komplexen Themenbereichs wird auf die Darstellungspraxis der Dichten ...

  17. Paulus as vredemaker. Oor die resepsie van die Brief aan Filemon ...

    African Journals Online (AJOL)

    7 Jul 2015 ... Inleiding. Die woord 'vrede' kom net een maal in die Filemonbrief voor, en wel in die aanhef van die brief. Kommentatore merk egter gereeld op dat 'n mens nie daaruit moet aflei dat dié begrip onbelangrik vir die verstaan van die brief is nie. Om een voorbeeld te noem: Barth en Blanke. (2002) skryf as volg:.

  18. Die berekening van vloeiing in ’n roterende annulus deur die metode van kunsmatige saamdrukbaarheid

    Directory of Open Access Journals (Sweden)

    H. Grobler

    1987-03-01

    Full Text Available Die vloeiing van ’n onsaamdrukbare, viskeuse vloeier word ondersoek aan die hand van die numeriese oplossing van die gediskretiseerde Navier-Stokes- en kontinuiteitsbeheervergelykings. In die besonder word vloeiing in ’n annulus bestaande uit twee koaksiale silinders wat elk ten opsigte van die ander kan roteer, en met ’n voorgeskrewe drukval oor die lengte van die silinder, beskou. Die oplossings word bereken deur die toepassing van Chorin se metode van kunsmatige saamdrukbaarheid, waarin die tydonafhanklike beheervergelykings getransformeer word na tydafhanklike hulpvergelykings deur die invoering van ’n kunsmatige toestandsvergelyking. Die oplossing van die hulpvergelykings konvergeer na ’n stasionêre oplossing, wat ooreenstem met die oplossing van die oorspronklike tydonafhanklike beheervergelykings. Die gedrag van die vloeier, wanneer ten voile ontwikkelde laminêre vloeiing bereik word, is met sukses bereken. ’n Eenvoudige model vir die bepaling van ontwikkeling van vloeiing langs die annulus vir enige gegewe invloeisnelheidsprofiel word voorgestel. Die berekende resultate stem ooreen met die resultate wat uit die fisika van die probleem verwag word.

  19. Dosimetric comparison between the microSelectron HDR 192Ir v2 source and the BEBIG 60Co source for HDR brachytherapy using the EGSnrc Monte Carlo transport code

    International Nuclear Information System (INIS)

    Anwarul Islam, M.; Akramuzzaman, M.M.; Zakaria, G.A.

    2012-01-01

    Manufacturing of miniaturized high activity 192 Ir sources have been made a market preference in modern brachytherapy. The smaller dimensions of the sources are flexible for smaller diameter of the applicators and it is also suitable for interstitial implants. Presently, miniaturized 60 Co HDR sources have been made available with identical dimensions to those of 192 Ir sources. 60 Co sources have an advantage of longer half life while comparing with 192 Ir source. High dose rate brachytherapy sources with longer half life are logically pragmatic solution for developing country in economic point of view. This study is aimed to compare the TG-43U1 dosimetric parameters for new BEBIG 60 Co HDR and new microSelectron 192 Ir HDR sources. Dosimetric parameters are calculated using EGSnrc-based Monte Carlo simulation code accordance with the AAPM TG-43 formalism for microSelectron HDR 192 Ir v2 and new BEBIG 60 Co HDR sources. Air-kerma strength per unit source activity, calculated in dry air are 9.698x10 -8 ± 0.55% U Bq -1 and 3.039x10 -7 ± 0.41% U Bq -1 for the above mentioned two sources, respectively. The calculated dose rate constants per unit air-kerma strength in water medium are 1.116±0.12% cGy h -1 U -1 and 1.097±0.12% cGy h -1 U -1 , respectively, for the two sources. The values of radial dose function for distances up to 1 cm and more than 22 cm for BEBIG 60 Co HDR source are higher than that of other source. The anisotropic values are sharply increased to the longitudinal sides of the BEBIG 60 Co source and the rise is comparatively sharper than that of the other source. Tissue dependence of the absorbed dose has been investigated with vacuum phantom for breast, compact bone, blood, lung, thyroid, soft tissue, testis, and muscle. No significant variation is noted at 5 cm of radial distance in this regard while comparing the two sources except for lung tissues. The true dose rates are calculated with considering photon as well as electron transport using

  20. Die kritiek van tradisie en die tradisie van kritiek in die Geesteswetenskappe. 'n Rekonstruksie van die debat tussen Habermas en Gadamer

    OpenAIRE

    Duvenage, Pieter

    2013-01-01

    In hierdie bydrae word die bekende debat (1967-1971) tussen Jürgen Habermas en Hans-Georg Gadamer gerekonstrueer. Die debat word hier in noue samehang met die kwessie van die geesteswetenskappe gelees. Die bydrae val in vier dele uiteen. In die eerste afdeling word Habermas se opening tot die debat in vyf onderafdelings uiteengesit. Dit gaan hier oor Gadamer se verdediging van tradisie en Habermas se kritiek op die begrip (1.1). In antwoord op Gadamer se begrip van tradisie ontwerp Habermas s...

  1. Enkele opmerkings oor die intrinsieke waarde van die Latynse teks van Kodeks Bezae as herstelbron vir die Griekse teks van die Nuwe Testament

    Directory of Open Access Journals (Sweden)

    G. J.C. Jordaan

    1985-05-01

    Full Text Available Een van die belangrikste oud-Latynse vertalings word gevind in Kodeks Bezae, ’n vyfde-eeuse manuskrip van die vier Evangelies. Kodeks Bezae bevat ’n Griekse teks (D en ’n Latynse teks (d van die Evangelies langs mekaar, die Latynse teks in ’n lettertipe wat baie aan die Griekse majuskelskrif herinner. Wat hierdie dokument so merkwaardig maak, is die feit dat dit die enigste manuskrip is wat ’n Griekse Evangelie-teks uit die Westerse teksfamilie bevat.

  2. Preliminary results of intersticial HDR brachytherapy in association with conservative surgery for soft tissue sarcomas

    International Nuclear Information System (INIS)

    Pellizzon, A.C.A; Ferrigno, R.; Trippe, N.; Novaes, P.; Salvajoli, J.V.; Fogareli, R.; Maja, M.A.C.; Baraldi, H.

    1996-01-01

    From january 1994 to january 1995 seven patients were treated with conservative surgery in association to postoperative HDR brachytherapy through Micro-Selectron HDR. Four patients were male and three female, the ages ranged from 20 to 60 years old and the main site of the tumor were at the extremities and just one had a perineal lesion. The follow up ranged from 4 to 24 months. Most of the implants were done through single plane technic. Definition of the treatment volume was based on CT scans and metallic clips inserted during the surgery. The prescribed dose was at 10mm from the implant plane. The patient with perineal lesion had a volumetric implant and the dose prescription was based on Paris System, in which the total volume of the tumor bed must be included in a 85% isodose curve. The number of catheters used ranged from 6 to 14 and the active length from 20 to 150mm, placed intraoperatively. The volumetric implant was performed through perineal template to guide the needles in number of nine and an active length of 60mm. The prescribed dose ranged from 20 to 25Gy when associated with EBRT and 30 to 35Gy when brachytherapy alone was used. Results: All patients had local control. Acute complications were observed only in the skin, limited to mild erytema and dry descanation. Conclusions: Although the number of the patients is small, this procedure has been shown to be effective in local control when associated to conservative surgery, can be easily and safely done and gives the possibilities of dose optimization

  3. SU-F-T-11: Scintillator Based Quality Assurance Device for HDR Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jozsef, G [New York University Medical Center, New York, NY (United States)

    2016-06-15

    Purpose: To build a test device for HDR afterloaders capable of checking source positions, times at positions and estimate the activity of the source. Methods: A catheter is taped on a plastic scintillation sheet. When a source travels through the catheter, the scintillator sheet lights up around the source. The sheet is monitored with a video camera, and records the movement of the light spot. The center of the spot on each image on the video provides the source location, and the time stamps of the images can provide the dwell time the source spend in each location. Finally, the brightness of the light spot is related to the activity of the source. A code was developed for noise removal, calibrate the scale of the image to centimeters, eliminate the distortion caused by the oblique view angle, identifying the boundaries of the light spot, transforming the image into binary and detect and calculate the source motion, positions and times. The images are much less noisy if the camera is shielded. That requires that the light spot is monitored in a mirror, rather than directly. The whole assembly is covered from external light and has a size of approximately 17×35×25cm (H×L×W) Results: A cheap camera in BW mode proved to be sufficient with a plastic scintillator sheet. The best images were resulted by a 3mm thick sheet with ZnS:Ag surface coating. The shielding of the camera decreased the noise, but could not eliminate it. A test run even in noisy condition resulted in approximately 1 mm and 1 sec difference from the planned positions and dwell times. Activity tests are in progress. Conclusion: The proposed method is feasible. It might simplify the monthly QA process of HDR Brachytherapy units.

  4. Dosimetric analysis at ICRU reference points in HDR-brachytherapy of cervical carcinoma.

    Science.gov (United States)

    Eich, H T; Haverkamp, U; Micke, O; Prott, F J; Müller, R P

    2000-01-01

    In vivo dosimetry in bladder and rectum as well as determining doses on suggested reference points following the ICRU report 38 contribute to quality assurance in HDR-brachytherapy of cervical carcinoma, especially to minimize side effects. In order to gain information regarding the radiation exposure at ICRU reference points in rectum, bladder, ureter and regional lymph nodes those were calculated (digitalisation) by means of orthogonal radiographs of 11 applications in patients with cervical carcinoma, who received primary radiotherapy. In addition, the doses at the ICRU rectum reference point was compared to the results of in vivo measurements in the rectum. The in vivo measurements were by factor 1.5 below the doses determined for the ICRU rectum reference point (4.05 +/- 0.68 Gy versus 6.11 +/- 1.63 Gy). Reasons for this were: calibration errors, non-orthogonal radiographs, movement of applicator and probe in the time span between X-ray and application, missing connection of probe and anterior rectal wall. The standard deviation of calculations at ICRU reference points was on average +/- 30%. Possible reasons for the relatively large standard deviation were difficulties in defining the points, identifying them on radiographs and the different locations of the applicators. Although 3 D CT, US or MR based treatment planning using dose volume histogram analysis is more and more established, this simple procedure of marking and digitising the ICRU reference points lengthened treatment planning only by 5 to 10 minutes. The advantages of in vivo dosimetry are easy practicability and the possibility to determine rectum doses during radiation. The advantages of computer-aided planning at ICRU reference points are that calculations are available before radiation and that they can still be taken into account for treatment planning. Both methods should be applied in HDR-brachytherapy of cervical carcinoma.

  5. Exclusive radiation therapy of endometrial carcinoma using HDR Co-60 and Cf-252 sources

    International Nuclear Information System (INIS)

    Inciura, A.; Janulionis, E.; Atkocius, V.

    2000-01-01

    Although the main treatment of endometrial cancer is surgery, the gross spread of carcinoma in pelvis, elderly age of the patients and serious therapeutical diseases do not allow to operate 20% of the patients. For these patients only radical treatment decision is the combined radiation therapy. However, using various modalities of combined radiotherapy, the treatment results are not satisfying: only 52% of patients survive 5 years. There was implemented a new method of combined radiotherapy, using a three-channel applicator with two-positional locating of HDR Co-60 radioactive sources (group I). A new method of brachytherapy for endometrial carcinoma using a HDR Cf 252 sources (group II) was implemented too. For group I the medium total dose of the point A was 77.6 Gy, point I - 69.6 Gy. point 2 - 84.2 Gy, point B - 52.6 Gy, For group II the medium total dose the points A, 3 and 4 was 50 iGy. For group I 1 year overaII survival rate was 85%, 3 year - 73%. The 3 year survival rate for stage I was 79%, for stage II - 89%, for stage III - 33%. 3 year survival for highly virulent tumours - 56% and for low virulent (adenocarcinoma) - 82% was statistically different. The loss of tumour differentiation correlated with the worse prognosis: 3 year survival for G1 and G2 tumours was 92%, for G3 - 45%. Low hemoglobin level was also associated with low survival rate: 2 year survival for Hb≥120g/l was 85% and Hb<120g/l - 23%. 1 year survival rate was 87%, 3 year - 66%, 5 year - 58% for group II, treated with Cf-252. Radiation complications occurred for 13.8% of the patients for group I and 6.2% for group II. Good survival rates and a small number of complications sufficiently proofed treatment method. (author)

  6. Ir-192 HDR transit dose and radial dose function determination using alanine/EPR dosimetry

    International Nuclear Information System (INIS)

    Calcina, Carmen S Guzman; Almeida, Adelaide de; Rocha, Jose R Oliveira; Abrego, Felipe Chen; Baffa, Oswaldo

    2005-01-01

    Source positioning close to the tumour in high dose rate (HDR) brachytherapy is not instantaneous. An increment of dose will be delivered during the movement of the source in the trajectory to its static position. This increment is the transit dose, often not taken into account in brachytherapeutic treatment planning. The transit dose depends on the prescribed dose, number of treatment fractions, velocity and activity of the source. Combining all these factors, the transit dose can be 5% higher than the prescribed absorbed dose value (Sang-Hyun and Muller-Runkel, 1994 Phys. Med. Biol. 39 1181-8, Nath et al 1995 Med. Phys. 22 209-34). However, it cannot exceed this percentage (Nath et al 1995). In this work, we use the alanine-EPR (electron paramagnetic resonance) dosimetric system using analysis of the first derivative of the signal. The transit dose was evaluated for an HDR system and is consistent with that already presented for TLD dosimeters (Bastin et al 1993 Int. J. Radiat. Oncol. Biol. Phys. 26 695-702). Also using the same dosimetric system, the radial dose function, used to evaluate the geometric dose degradation around the source, was determined and its behaviour agrees better with those obtained by Monte Carlo simulations (Nath et al 1995, Williamson and Nath 1991 Med. Phys. 18 434-48, Ballester et al 1997 Med. Phys. 24 1221-8, Ballester et al 2001 Phys. Med. Biol. 46 N79-90) than with TLD measurements (Nath et al 1990 Med. Phys. 17 1032-40)

  7. Poster - Thur Eve - 03: LDR to HDR: RADPOS applications in brachytherapy.

    Science.gov (United States)

    Cherpak, A J; Cygler, J E; Kertzscher, G; E, C; Perry, G

    2012-07-01

    The RADPOS in vivo dosimetry system combines an electromagnetic positioning sensor and either one or five MOSFET dosimeters. The feasibility of using the system for quality control has been explored for a range of radiotherapy treatment techniques including most recently transperineal interstitial permanent prostate brachytherapy and high dose rate (HDR) treatments. Dose and position information was collected by a RADPOS array detector inside a Foley catheter within patients' urethra during permanent seed implantation. Ten patients were studied, and average displacement during implantation was Δr = (1.4-5.1) mm, with movements up to 9.7 mm due to the removal of the transrectal ultrasound probe. Maximum integral dose in the prostatic urethra ranged from 110-195 Gy, and it was found that the dose can change up to 63 cGy (62.0%) depending on whether the rectal probe is in place. For HDR, a RADPOS detector was first calibrated with an Ir-192 source. A treatment was then simulated using a total of 50 dwell positions in 5 catheters in an acrylic phantom. Dwell positions ranged from 1 to 10 cm away from the RADPOS detector and dose was measured for each source position. An average calibration coefficient of 0.74±0.11 cGy/mV was calculated for the detector and the average absolute difference between measured values and expected dose was 0.7±5.4 cGy (5±20%). The demonstrated accuracy of RADPOS dose measurements along with its ability to simultaneously measure displacement makes it a powerful tool for brachytherapy treatments, where high dose gradients can present unique in vivo dosimetry challenges. © 2012 American Association of Physicists in Medicine.

  8. Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy

    International Nuclear Information System (INIS)

    Balvert, Marleen; Gorissen, Bram L; Den Hertog, Dick; Hoffmann, Aswin L

    2015-01-01

    Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell time modulation restriction (DTMR) that limits dwell time differences between neighboring dwell positions has been suggested to eliminate this problem. DTMRs may additionally reduce the sensitivity for uncertainties in dwell positions that inevitably result from catheter reconstruction errors and afterloader source positioning inaccuracies. This study quantifies the reduction of high-dose subvolumes and the robustness against these uncertainties by applying a DTMR to template-based prostate HDR brachytherapy implants. Three different DTMRs were consecutively applied to a linear dose-based penalty model (LD) and a dose-volume based model (LDV), both obtained from literature. The models were solved with DTMR levels ranging from no restriction to uniform dwell times within catheters in discrete steps. Uncertainties were simulated on clinical cases using in-house developed software, and dose-volume metrics were calculated in each simulation. For the assessment of high-dose subvolumes, the dose homogeneity index (DHI) and the contiguous dose volume histogram were analysed. Robustness was measured by the improvement of the lowest D 90% of the planning target volume (PTV) observed in the simulations. For (LD), a DTMR yields an increase in DHI of approximately 30% and reduces the size of the largest high-dose volume by 2–5 cc. However, this comes at a cost of a reduction in D 90% of the PTV of 10%, which often implies that it drops below the desired minimum of 100%. For (LDV), none of the DTMRs were able to improve high-dose volume measures. DTMRs were not capable of improving robustness of PTV D 90% against uncertainty in dwell positions for both models. (paper)

  9. An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

    Science.gov (United States)

    Borot de Battisti, M.; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

    2015-10-01

    Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance. However, MR-guided needle placement is currently not possible due to space restrictions in the closed MR bore. To overcome this problem, a MR-compatible, single-divergent needle-implant robotic device is under development at the University Medical Centre, Utrecht: placed between the legs of the patient inside the MR bore, this robot will tap the needle in a divergent pattern from a single rotation point into the tissue. This rotation point is just beneath the perineal skin to have access to the focal prostate tumor lesion. Currently, there is no treatment planning system commercially available which allows optimization of the dose distribution with such needle arrangement. The aim of this work is to develop an automatic inverse dose planning optimization tool for focal HDR prostate brachytherapy with needle insertions in a divergent configuration. A complete optimizer workflow is proposed which includes the determination of (1) the position of the center of rotation, (2) the needle angulations and (3) the dwell times. Unlike most currently used optimizers, no prior selection or adjustment of input parameters such as minimum or maximum dose or weight coefficients for treatment region and organs at risk is required. To test this optimizer, a planning study was performed on ten patients (treatment volumes ranged from 8.5 cm3to 23.3 cm3) by using 2-14 needle insertions. The total computation time of the optimizer workflow was below 20 min and a clinically acceptable plan was reached on average using only four needle insertions.

  10. TU-D-201-06: HDR Plan Prechecks Using Eclipse Scripting API

    Energy Technology Data Exchange (ETDEWEB)

    Palaniswaamy, G; Morrow, A; Kim, S; Rangaraj, D [Baylor Scott & White Health, Temple, TX (United States)

    2016-06-15

    Purpose: Automate brachytherapy treatment plan quality check using Eclipse v13.6 scripting API based on pre-configured rules to minimize human error and maximize efficiency. Methods: The HDR Precheck system is developed based on a rules-driven approach using Eclipse scripting API. This system checks for critical plan parameters like channel length, first source position, source step size and channel mapping. The planned treatment time is verified independently based on analytical methods. For interstitial or SAVI APBI treatment plans, a Patterson-Parker system calculation is performed to verify the planned treatment time. For endobronchial treatments, an analytical formula from TG-59 is used. Acceptable tolerances were defined based on clinical experiences in our department. The system was designed to show PASS/FAIL status levels. Additional information, if necessary, is indicated appropriately in a separate comments field in the user interface. Results: The HDR Precheck system has been developed and tested to verify the treatment plan parameters that are routinely checked by the clinical physicist. The report also serves as a reminder or checklist for the planner to perform any additional critical checks such as applicator digitization or scenarios where the channel mapping was intentionally changed. It is expected to reduce the current manual plan check time from 15 minutes to <1 minute. Conclusion: Automating brachytherapy plan prechecks significantly reduces treatment plan precheck time and reduces human errors. When fully developed, this system will be able to perform TG-43 based second check of the treatment planning system’s dose calculation using random points in the target and critical structures. A histogram will be generated along with tabulated mean and standard deviation values for each structure. A knowledge database will also be developed for Brachyvision plans which will then be used for knowledge-based plan quality checks to further reduce

  11. Die gebruik van die mite in Die werfbobbejaan van Alexander Strachan

    Directory of Open Access Journals (Sweden)

    E. M.M. Klopper

    1996-05-01

    Full Text Available The use of myths in Die werfbobbejaan by Alexander Strachan This article focuses on the rote of Zulu myths in Alexander Strachan’s novel Die werfbobbejaan. It lakes as point of departure sources on mythology like Cuddon (1991, Baldick (1990, Grimal (1969, Levi-Strauss (1979 and Jung (1969. Die werfbobbejaan essentially recounts the story of a man (the adventurer, the academic, the writer, the hunter who also is the central character in Strachan's two preceding novels. Die werfbobbejaan focuses on the completion of an individuation process in the life of the central character, a process already begun in the preceding two novels and which in this novel finally culminates in the confrontation between hunter and baboon. The completion of this process is facilitated by the African milieu of Zululand where people give meaning to their existence by means of myths, and where no distinction is made between the mythic and rational modes of experiencing reality.

  12. Die rol van die onderwys in die handhawing en uitbouing van ons volkskultuur

    Directory of Open Access Journals (Sweden)

    G.J. Jordaan

    1970-03-01

    Full Text Available Op die oog af lyk dit ’n baie maklike onderwerp, maar hoe meer 'n mens daaroor nadink hoe ingewikkelder en omvangryker word die implikasies wat verband hou. Dit is veral so omdat dit hier voor alles gaan om eerste fundamentele uitgangspunte, dit wil sê, om lewens- en wêreldbeskouing. Dit geld van albei komponente — van onderwys sowel as van kultuur.

  13. Die vraag na ’n nuwe belydenisskrif

    Directory of Open Access Journals (Sweden)

    J. H. van Wyk

    1974-05-01

    Full Text Available Die mees bekende reformatoriese belydenisskrifte dateer uit die sestiende en sewentiende eeue (E 16—17 en is dus almal 300 tot 400 jaar oud: Die Galliese Konfessie 1559, die Nederlandse Geloofsbelydenis 1561, die Heidelbergse Kategismus 1563, die 39 Articles 1563, die Tweede Helvietiese Konfessie 1566, die Dordtse Leerreëls 1619, die Westminsterse Konfessie 1646.

  14. as by die huisbesoek. HP WOLMARANS. PROF. DR. SP ...

    African Journals Online (AJOL)

    Test

    van 'n evangeüedienaar wat alles fei! gehad het vir die werk en werk kring waartoe God hom geroep het. Hy is dan ook werklik die eerste grondlegger van die gemeente in Zoutpansberg en die man wat dit opgewerk het. Die geskiedenis van Hofmeyer is die geskiedenis van die kerk- vereniging en die redes waarom die ...

  15. Die krisis van ongeloof in Numeri 13-14

    African Journals Online (AJOL)

    Die ver- haal gebruik die aanloklikheid van die land as 'n submotief om 'n groter drama uit te beeld: die konflik tussen Israel en sy God. ISSN 0259 9422 ... In aansluiting by Eksodus 34 laat die liefde en trou van die Here aan Horn die ...... langs die weg van die tema van veertig jaar dat 'de hoofdstukken 13-14 een sleutel-.

  16. Virtual HDR CyberKnife SBRT for Localized Prostatic Carcinoma: 5-year Disease-free Survival and Toxicity Observations

    Directory of Open Access Journals (Sweden)

    Donald Blake Fuller

    2014-11-01

    Full Text Available PURPOSEProstate stereotactic body radiotherapy (SBRT may substantially recapitulate the dose distribution of high-dose-rate (HDR brachytherapy, representing an externally delivered Virtual HDR treatment method. Herein we present 5-year outcomes from a cohort of consecutively treated Virtual HDR SBRT prostate cancer patients.METHODSSeventy-nine patients were treated from 2006 - 2009, 40 low-risk and 39 intermediate-risk, under IRB-approved clinical trial, to 38 Gy in 4 fractions. The planning target volume (PTV included prostate plus a 2-mm volume expansion in all directions, with selective use of a 5-mm prostate-to-PTV expansion and proximal seminal vesicle coverage in intermediate-risk patients, to better cover potential extraprostatic disease; rectal PTV margin reduced to zero in all cases. The prescription dose covered > 95% of the PTV (V100 >= 95%, with a minimum 150% PTV dose escalation to create HDR-like PTV dose distribution.RESULTSMedian pre-SBRT PSA level of 5.6 ng/mL decreased to 0.05 ng/mL 5 years out and 0.02 ng/mL 6 years out. At least one PSA bounce was seen in 55 patients (70% but only 3 of them subsequently relapsed, Biochemical-relapse-free survival was 100% and 92% for low-risk and intermediate-risk patients, respectively, by ASTRO definition (98% and 92% by Phoenix definition. Local relapse did not occur, distant metastasis-free survival was 100% and 95% by risk-group, and disease-specific survival was 100%. Acute and late grade 2 GU toxicity incidence was 10% and 9%, respectively; with 6% late grade 3 GU toxicity. Acute urinary retention did not occur. Acute and late grade 2 GI toxicity was 0% and 1%, respectively, with no grade 3 or higher toxicity. Of patients potent pre-SBRT, 65% remained so at 5 years.CONCLUSIONSVirtual HDR prostate SBRT creates a very low PSA nadir, a high rate of 5-year disease-free survival and an acceptable toxicity incidence, with results closely resembling those reported post-HDR brachytherapy.

  17. Additional androgen deprivation makes the difference. Biochemical recurrence-free survival in prostate cancer patients after HDR brachytherapy and external beam radiotherapy

    International Nuclear Information System (INIS)

    Schiffmann, Jonas; Tennstedt, Pierre; Beyer, Burkhard; Boehm, Katharina; Tilki, Derya; Salomon, Georg; Graefen, Markus; Lesmana, Hans; Platz, Volker; Petersen, Cordula; Kruell, Andreas; Schwarz, Rudolf

    2015-01-01

    The role of additional androgen deprivation therapy (ADT) in prostate cancer (PCa) patients treated with combined HDR brachytherapy (HDR-BT) and external beam radiotherapy (EBRT) is still unknown. Consecutive PCa patients classified as D'Amico intermediate and high-risk who underwent HDR-BT and EBRT treatment ± ADT at our institution between January 1999 and February 2009 were assessed. Multivariable Cox regression models predicting biochemical recurrence (BCR) were performed. BCR-free survival was assessed with Kaplan-Meier analyses. Overall, 392 patients were assessable. Of these, 221 (56.4 %) underwent trimodality (HDR-BT and EBRT and ADT) and 171 (43.6 %) bimodality (HDR-BT and EBRT) treatment. Additional ADT administration reduced the risk of BCR (HR: 0.4, 95 % CI: 0.3-0.7, p < 0.001). D'Amico high-risk patients had superior BCR-free survival when additional ADT was administered (log-rank p < 0.001). No significant difference for BCR-free survival was recorded when additional ADT was administered to D'Amico intermediate-risk patients (log-rank p = 0.2). Additional ADT administration improves biochemical control in D'Amico high-risk patients when HDR-BT and EBRT are combined. Physicians should consider the oncological benefit of ADT administration for these patients during the decision-making process. (orig.) [de

  18. Der Nahostkonflikt und die Medien

    Directory of Open Access Journals (Sweden)

    Carola Richter

    2014-06-01

    Full Text Available Diese Einführung in eine Themenausgabe zu den vielfältigen Rollen der Medien im Nahostkonflikt skizziert die Probleme, die sich für Medien und Journalisten als Akteure im Konflikt, Adressaten der Konfliktparteien und Anlass für Konflikt durch ihre Berichterstattung ergeben. Das Konfliktgebiet Israel und Palästina ist sowohl für Forschung über Auslandsbericht-erstattung, über transnationale Agenda Building- und Public Diplomacy-Prozesse als auch über mediensystemische Entwicklungen in Besatzer- und Besatzungsgebieten interessant. Der Artikel gibt einen Überblick über das Feld und führt dabei in die in der Themenausgabe präsentierten empirischen Studien zum Nahostkonflikt und den Medien ein.

  19. DIE VRYWILLIGERSMAGTE VAN GRIEKWALAND-WES

    African Journals Online (AJOL)

    teen gekant was, is dit op 15 Oktober 1880 by die Kaapkolonie ingelyf.9. Gedurende sy kortstondige bestaan van minder as 'n dekade lank het die kroonkolonie Griekwa- land-Wes met talle finansiele, ekonomiese, so- siale en ander probleme te doen gehad. Een van die ernstige probleme was die bedreiging wat.

  20. Die Gereformeerde Ekumeniese Sinode en Sending 1984

    African Journals Online (AJOL)

    opvatting. Indien 'n mens al die kerke wat aan die Gereformeerde. Ekumeniese Sinode (GES) behoort een vir een sendingmatig sal be- studeer, sal daar waarskynlik 'n sterk differensiasie tussen sommige kerke aan die lig kom. Die GES kan dus nie verantwoordelik gehou word vir individuele kerke se sendingopvatting nie.

  1. voorgeskiedenis tot die stigting van 'n unieverdedigingsmag

    African Journals Online (AJOL)

    gesien nie en toe die wetsontwerp op 23 Februa- rie 1912 deur Smuts in sy hoedanigheid as Mi- nister van Verdediging ingedien is, het Beyers heelwat kritiek daarop gehad. Beyers het be- weer dat dit op vergaderings geblyk het dat die volk wou he Engeland moet steeds die verdedi- ging waarneem aangesien die Unie ...

  2. Moderne diskoerse in die teologie vandag

    Directory of Open Access Journals (Sweden)

    J.H. van Wyk

    2013-05-01

    Full Text Available In hierdie artikel word aandag gevra vir enkele moderne diskoerse in die teologie vandag. Volgens die outeur staan die vrae oor God, Jesus, die mens en die aarde in die sentrum van belangstelling en oorheers dit in ’n groot mate die teologiese debat. Die opkoms van die moderne aggressiewe ateïsme, die wetenskaplike navorsing oor die historiese Jesus, die groeiende vrae oor die mens en die menslike samelewing, asook die dreigende ekologiese krisis op aarde, sorg vir nuwe debatte van ongekende omvang. Die outeur bespreek hierdie debatte oorsigtelik, met kritiek waar nodig, en sluit af met enkele rigtingwysers van wat hy as ‘goeie teologie’ verstaan. In this article attention is paid to some modern discourses in theology today. According to the author the questions about God, Jesus, man and the earth are in the centre of interest and to a large extent dominate the theological debate. The rise of modern aggressive atheism, the scientific research on the historic Jesus, the growing questions about man and human society as well as the threatening ecological crisis on earth, provide new discourses of unparalleled magnitude. The author provides a broad summary of these discourses, with criticism where necessary, and concludes with some indicators of his view what can be called ‘good theology’.

  3. DIE BEPERKING VAN MULTIOVULASIES IN KARAKOELOOIE NA ...

    African Journals Online (AJOL)

    Die geboorte van meer as 2 lammers per ooi is egter ongewens in die Karakoelbedryf aangesien dit aanleiding gee tot kleiner pelse veral wanneer voedingstoestande nie opti- maal is nie. In stoetteling is selfs tweelinge nie gewens nie, aangesien die ware fenotipiese waarde van die lammers nie in tweelinge te voorskyn ...

  4. Calvyn en die kerklike orde: Enkele opmerkings

    African Journals Online (AJOL)

    Om dié saak verder te belig word ook van die latere uitsprake van Calvyn in hierdie verband in berekening gebring. Met hierdie beperkte studie word dus in die eerste plek die feit in herinnering geroep dat dit vanjaar 450 jaar gelede is dat Calvyn se. Institusie die eerste maal in Basel verskyn het. Terselfdertyd word hier-.

  5. Leerteoretiese basis van die andragogie

    Directory of Open Access Journals (Sweden)

    C. J. A. Simpson

    1991-06-01

    Full Text Available Learning theory basis of andragogy. A cursory glance at andragogy creates the impression that humanistic learning theory plays an all encompassing role in the learner centered approach andragogy espouses. A closer look, however, reveals that Knowles (1973, after having made an intensive study of learning theory, created an extensive framework within which human resource development can take place. The fact that Knowles attracted critique from different areas, led to a need to ascertain the role different learning theories, if any, played in the emergence of andragogy. Having looked at the assumptions displayed by the andragogical approach, as well as a comparison of different learning theories and their connection with andragogy, it became clear that andragogy contains elements of various learning theories in an adapted way. These adaptations resulted in an approach to adult education in which learners are given the opportunity to be part of the learning process in such a way that they themselves contribute to the development which takes place. Opsomming Met 'n eerste oogopslag wil dit voorkom asof humanistiese leerteorie 'n oorheersende rol in die leerdergesentreerde benadering van andragogie speel. By nadere ondersoek blyk dit egter dat Knowles (1973, na 'n deeglike studie van verskillende leerteoretiese beginsels, 'n omvangryke raamwerk geskep het waarbinne, aan die hand van verskeie aangepaste leerteoretiese beginsels, menslike hulpbronontwikkeling kan plaasvind. As gevolg van die feit dat Knowles vanuit verskillende oorde kritiek op die lyf geloop het, is besluit om die rol wat verskillende leerteorieë in andragogie speel, te bestudeer. Dit blyk dat andragogie nie net elemente van verskillende leerteorieë bevat nie, maar dat toepaslike aspekte van die teoriee wat ondersoek is, benut en aangepas is om 'n geintegreerde benadering te bewerkstellig waarin veral volwassene-leerders by leergeleenthede en hulle selfontwikkeling betrek word.

  6. Method of treating tool steel die materials

    International Nuclear Information System (INIS)

    Cook, C.S.; Damon, S.

    1981-01-01

    In a method of hardening pilger dies to provide a hard case containing residual compressive stresses and tough body, the tool steel die is heated to the austenitizing temperature range, followed by selectively removing heat from the die at a predetermined faster rate in the direction of the desired case than the rate of heat removal from the balance of the die, and thereafter tempering the die. The invention provides a fully hardened and tempered case on the working surface of the die and a tough body in the balance of the die, usually of lower hardness. (author)

  7. Die «ASEAN-Wirtschaftsgemeinschaft»

    DEFF Research Database (Denmark)

    Juego, Bonn

    2014-01-01

    Seit dem Ende der 1990er-Jahre verfolgt die ASEAN die Vision einer politischen, wirtschaftlichen und sozialen Gemeinschaft. Doch wie realistisch ist die Umsetzung eines solch ambitionierten Vorhabens vor dem Hintergrund der enormen Heterogenität der Region? ASEAN vereint Staaten auf...... Entwicklungsstufen, wie sie unterschiedlicher kaum sein können. Der Autor, Bonn Juego, nimmt die ASEAN Vision 2020 sowie die Debatten, die diesbezüglich in den einzelnen Ländern geführt werden, unter die Lupe. Er geht dem Potenzial des ASEANAnsatzes zu sozialer Teilhabe und wirtschaftlicher Verteilungsgerechtigkeit...

  8. Die pastorale begeleiding van predikante van die Nederduitse ...

    African Journals Online (AJOL)

    21 Jan 2013 ... Stone, M.F., 1999, Coaching, counselling & mentoring: How to choose & use the right technique to boost employee performance, AMACOM, New York. Strydom, W.A., 2011, 'Pastoraat aan getraumatiseerde kinders in die intensiewesorgeenheid: 'n Gestalt benadering', DD tesis, Universiteit van Suid-. Afrika ...

  9. 'n Begronde bedieningsmodel vir die diakonia van die gemeente

    African Journals Online (AJOL)

    15 Feb 2012 ... At first, various angles of approach to the research on ministry in ... Lingenfelter 2005; Armour & Browning 2000) en daarmee saam die ...... Grobler, A.B. & Van der Walt, A.L., 2008, 'An assessment of the management skills.

  10. Die ontwikkeling van menslike potensiaal in die Republiek van Suid ...

    African Journals Online (AJOL)

    Erna Kinsey

    Dit het dus ook te doen met lewenstandaard, aangesien lewenstandaard `n bepalende faktor is met betrekking tot die optimale ontwikkeling van menslike potensiaal. Ander minder materiële aspekte van menslike potensiaal het te doen met menslike vryheid, waaronder vryheid van spraak, beweging en keuse ter sake is.

  11. UIT DIE VOORGESKIEDENIS VAN DIE SUID-AFRIKAANSE VLOOT ...

    African Journals Online (AJOL)

    20 van 1898 van die Kaapkolonie, getiteld The Navy Contribution. Act, i898 is a.m. ... as a contribution towards the annual expenditure by the ...... The above are inclusive of all allowances for lodging and provisions. Petty Officer Ins ...... that system we can retain full constitutional control not only in theory but also complete ...

  12. Die Korallenfauna des Perm von Timor und die permische Vereisung

    NARCIS (Netherlands)

    Gerth, H.

    1926-01-01

    Bei den zahlreichen Rekonstruktionen der klimatologischen Verhältnisse, die man für das Ende des Palaeozoikums gemacht hat, ist man fast immer von der Kohlenbildung, der Florenverbreitung und den Vereisungserscheinungen ausgegangen. Der marinen Tierwelt hat man bei der Behandlung dieser Fragen meist

  13. [Dying with cancer: Hollywood lessons].

    Science.gov (United States)

    Niemeyer, Fernanda; Kruse, Maria Henriqueta Luce

    2013-12-01

    The study attempts to understand how dying from cancer is portrayed by five movies produced in Hollywood between 1993 and 2006. Based on the cultural studies and their post-structuralism version and supported by the notions of discourse and subjectivity, as proposed by philosopher Michel Foucault, we suggest one of the possible readings of the movie picture corpus. We assess how the movie picture discourse acts as a cultural pedagogy that produces ways of seeing dying with cancer: immortalizing the healthy body image, silencing death, taking care of the dead body and, finally, accepting death. Our proposal is intended to stimulate reflections that may contribute to care and education in nursing.

  14. Existential Needs among the Dying

    DEFF Research Database (Denmark)

    Moestrup, Lene

    meaning making. Methods: The key research question is: 1. What kind of existential needs are central to dying cancer patients and their relatives during the terminal phase in Danish hospices? Exploring this highly sensitive and complex research area entails substantial ethical responsibility during data...... based and practice relevant knowledge about the complexity of existential considerations and needs among dying cancer patients and their relatives in a secularized society as Denmark. Existential needs are seen as a multidimensional concept that encompasses religious, spiritual and secular existential...

  15. ’n Etiek van liefde: Die etiese perspektiewe van die Heidelbergse Kategismus

    Directory of Open Access Journals (Sweden)

    Koos Vorster

    2013-06-01

    Full Text Available Hierdie artikel behandel die etiese perspektiewe van die Heidelbergse Kategismus – een van die prominente belydenisskrifte in die gereformeerde tradisie. Die etiese relevansie is ingebed in die konfessie se verklaring van die tien gebooie. Die artikel verduidelik dat die etiek van die Heidelbergse Kategismus ten diepste ’n karakteretiek is en dat dit gelowiges oproep tot ’n etiek van liefde. Hierdie liefde sluit in liefde vir die verbondsgemeenskap, die bediening van die Woord, die heiligheid van God en die waardigheid van mense, die gemeenskap van die gelowiges, gesag, die lewe, die huwelik, privaatbesit en arbeid asook waarheid en geregtigheid. As gevolg van die sinekdogeekarakter van die wet is hierdie etiek van liefde vandag baie relevant. This article deals with the ethical relevance of one of the prominent confessions in the reformed tradition, namely the Heidelberg Cathechism. The ethical relevance lies in the confession’s elucidation of the ten commandments and its application to moral conduct. The article explains that the ethics of the Heidelberg Catechism is essentially a virtue ethics calling for an ethics of love. This love should include love for the covenantal communion, ministry of the Word, the holiness of God and the dignity of people, the communion of the saints, authority, life, marriage, private property and labour, and truth and justice. Due to the synecdochical character of the ten commandments this ethics of love is highy relevant in the present times.

  16. HDR and LDR Brachytherapy in the Treatment of Lip Cancer: the Experience of the Catalan Institute of Oncology.

    Science.gov (United States)

    Ayerra, Arrate Querejeta; Mena, Estefanía Palacios; Fabregas, Joan Pera; Miguelez, Cristina Gutiérrez; Guedea, Ferran

    2010-03-01

    Lip cancer can be treated by surgery, external radiotherapy, and/or brachytherapy (BT). In recent years, BT has become increasingly favored for this type of cancer. The aim of the present study was to analyze local control and survival of patients treated at our institution between July 1989 and June 2008. We performed a retrospective study of 121 patients (109 males and 12 females) who underwent lip cancer brachytherapy from July 1989 to June 2008. Median age was 67 years and median follow-up was 31.8 months (range 20-188 months). Out of 121 patients, 100 (82.6%) were treated with low dose rate (LDR) BT while the remaining 21 patients (17.4%) received high dose rate (HDR) BT. The most common cell type was squamous cell carcinoma (115 cases; 95%) and most tumors were located on the lower lip (107 patients; 88.4%). Most cases were either stage T1 (62 patients; 51.2%), or T2 (44 cases; 36.4%). After 15 years of follow-up, overall survival was 89.5%, cause-specific survival 97.8%, and disease-free survival 86.6%. Local, regional, and distant control at 15 years were 90%, 92%, and 98.8%, respectively. Grade 3 mucosal toxicity was observed in 23% of patients treated with LDR compared to 33% of HDR patients, and grade 4 mucosal toxicity in 9% versus 0% in the HDR group. Our findings confirm that brachytherapy is an effective treatment for lip cancer. The results from our series are in line with those published elsewhere. Based on our limited data, HDR appears to be equally as good as LDR, although this needs to be confirmed by further studies.

  17. 13. status report of the project HDR safety program of Kernforschungszentrum Karlsruhe. Working report 05.46/89

    International Nuclear Information System (INIS)

    Katzenmeier, G.

    1989-01-01

    The programme phase III, which extends to the end of 1991, is divided into the part projects containment behaviour in extreme accidents, long-term damage and monitoring the components in operation, behaviour of damaged components in dynamic accidents and large fires of actual materials. The main aims, state of the HDR safety programme, main points of the programme for 1990 and 8 technical reports on phase II and III are documented. There is a survey of costs. (DG) [de

  18. Die Freunde im und die Freude am Fernsehen

    Directory of Open Access Journals (Sweden)

    Amina Ovcina Cajacob

    2012-09-01

    Full Text Available Das Ziel der vorliegenden Arbeit besteht darin, die Wirkungen von Popstars und Popbands auf Jugendliche (13- bis 17-Jährige zu erforschen. Im Mittelpunkt der Interessen steht die Frage, welche Wirkungen aus der Rezeption von Musiksendungen (bzw. Videoclips von Musiksendern entstehen und welche Charakteristika innerhalb der aufgebauten Beziehungen zu den Stars bemerkbar sind. Andererseits wurden die Unterschiede und Parallelen zwischen parasozialen Beziehungen zu den Stars und orthosozialen Beziehungen aufgezeigt. Im Zusammenhang mit der empirischen Untersuchung bezieht sich die Autorin auf den Uses-and-Gratifications-Approach, wobei die bedürfnissbefriedigenden Wirkungen von Musikkanälen und den dazu gehörigen Popstars im Mittelpunkt stehen. Mit Hilfe des Uses-and-Gratifications-Approach wird angenommen, dass das Konsumieren der Musiksendungen und der Musikstars von den Jugendlichen gezielt zur Befriedigung bestimmter Bedürfnisse eingesetzt wird.The objective of this study is to explore the effects of pop stars on adolescents (aged between 13 and 17. The focus of interest is the question what effect music channels (i.e. video clips from music channels produce and what characteristics are noticeable from the formed relationship between adolescents and pop stars. On the other side, parallels and differences have been drawn between the para-social relationships to pop stars and ortho-social relationships. In connection with empirical study, the author also refers to Uses-and Gratification-Approach where the need satisfying effects of music channels and pop stars are in focus. With the help of Uses-and Gratification-Approach it will be assumed, that aim of watching music channels and therefore pop stars will be pointed toward the gratification of specific needs.

  19. Die WTO in Hongkong: Zwischenergebnisse einer "Entwicklungsrunde"

    OpenAIRE

    Küblböck, Karin; Six, Clemens

    2006-01-01

    Die sechste Ministerkonferenz der Welthandelsorganisation (WTO), die von 13. bis 18. Dezember 2005 in Hongkong stattfand, war mit dem Anspruch angetreten, die Agenda der Doha-Entwicklungsrunde, also die B erücksichtigung der Interessen und ökonomischen Bedürfnisse der Entwicklungsländer und insbesondere der am wenigsten entwickelten Staaten, um wesentliche Schritte im Hinblick auf einen erfolgreichen Abschluss voranzubringen. Die Ergebnisse sind vor dem Hintergrund des Anspruches dieser Verha...

  20. Chirurgie in die Grieks-Romeinse era

    Directory of Open Access Journals (Sweden)

    François P. Retief

    2006-09-01

    Full Text Available In die Grieks-Romeinse era het mediese behandeling kenmerkend uit drie elemente bestaan, naamlik regimen (dieet en gesonde leefwyse, geneesmiddels en chirurgie – laasgenoemde alleen toegepas indien regimen en geneesmiddels onsuksesvol was. Bewyse van primitiewe chirurgie dateer terug na die Bronstydperk, en in Homerus se eposse is heelwat vermelding van die chirurgiese hantering van oorlogswonde, met tussenkoms van die gode. Met die koms van empiriese geneeskunde in die 5de eeu v.C. het chirurgie in die Hippokratiese Corpus prominent gefigureer met beduidende bydraes in veral die ortopediese veld en hoofbeserings. Uitbouing van anatomiese en fisiologiese kennis, gebaseer op disseksie van menslike kadawers in Alexandrië vanaf die laat 4de eeu v.C., het chirurgie ’n hupstoot gegee. Teen die Romeinse era vanaf die 2de eeu v.C. het snykundetegnieke (en -instrumente beduidend verbeter, maar is steeds oorwegend deur Griekse geneeshere beoefen. Van geneeshere is steeds verwag om al drie bovermelde terapeutiese modaliteite te bemeester, maar chirurgie het meer aansien verwerf en daar is al meer in onderafdelings van chirurgie soos oogheelkunde, vrouesiektes en verloskunde, blaaskwale en mond- en keelsnykunde gespesialiseer. Militêre geneeskunde was in die Romeinse Ryk ’n belangrike aktiwiteit, en het veral traumachirurgie uitgebou. Betreding van die buik- en toraksholtes was nie meer noodwendig fataal nie, en veeartsenykunde het tot stand gekom. Die eerste beduidende chirurgiehandboek ná die Hippokratiese Corpus is in die 1ste eeu n.C. deur Celsus opgestel. Vanaf die 3de eeu het die chirurgieberoep min vordering gemaak, die beroepstaal het mettertyd van Grieks na Latyn verander en kundigheid is later veral deur Islam-geneeshere na die Middeleeue en later oorgedra.

  1. Bevordering van transformerende leer: Die skryf van ’n reflektiewe joernaal in die Natuurwetenskappe

    Directory of Open Access Journals (Sweden)

    Erna R. du Toit

    2012-03-01

    Full Text Available Die doel van die artikel is om aan te toon hoe die skryf van ’n reflektiewe joernaal in die Natuurwetenskappe die perspektiewe en denke van onderwysstudente kan transformeer en/of leer kan bevorder. Die studie maak voorspraak vir die gebruik van ’n reflektiewe joernaal as ’n instrument vir studente om betekenis te gee aan die leeromgewing vanuit verskillende perspektiewe deur te leer in praktyk. ’n Kwalitatiewe navorsingsmetode is gevolg om die inskrywings in ’n joernaal te analiseer aan die hand van bepaalde indikatore. Die bevindinge toon dat die meeste studente na die praktykervaring positief was en sommiges het tot ander perspektiewe vanweë hul ervaring gekom.

  2. Die invloed van drie kruisbestuiwers op die saadinhoud van Minneola tangelo (Citrus parodist x C reticulata

    Directory of Open Access Journals (Sweden)

    H. J. Esterhuizen

    1991-07-01

    Full Text Available Die invloed van verskillende kruisbestuiwers (Clementine, Empress en Valencia op die gemiddelde saadinhoud van Minneo­la tangelo is ondersoek. Clementine en Empress as kruisbestuiwers het die grootste invloed op die gemiddelde saadinhoud van die vrugte gehad, terwyl dié van Valencia nie noemenswaardig was nie. Die gemiddelde saadinhoud van die vrugte het afgeneem met toename in afstand vanaf die kruisbestuiwer. Indien ’n beperking op die afstand tussen kultivar en kruisbestuiwer geplaas word, sal ’n groter persentasie vrugte aan uitvoerstandaarde ten opsigte van saadinhoud voldoen.

  3. DIE ROL VAN DIE SUID-AFRIKAANSE WEERMAG IN NATUUR- EN ...

    African Journals Online (AJOL)

    sedert die vroeg 1900's deur die Weermag be- heer. In 1967 was dit die eerste militere terrein wat tot privaatnatuurreservaat verklaar is. Vhembe bestaan uit 4 hoofplantgemeenskappe nl. rivieraewerbos, vloedvlaktes, ranteveld en die sandveldplato. Wildsoorte op die terrein sl!Jit rooibokke, bosbokke, waterbokke, koedoes,.

  4. Die era van Suid-Afrika se militere hoogbloei met die ...

    African Journals Online (AJOL)

    4 Jun 1976 ... Die Toyota 1200 bakkie is geadverteer met die woorde 'Hier kom die pantserbakkie', teen die agtergrond van 'n olifant tenk.32. Daar is ook 'n betrekking deur Thorold en van Wyk geadverteer waar militere opleiding 'n voorvereiste was.33. Daar was ook films wat weermag en polisie gebasseer is wat in die ...

  5. Riglyne vir ‘n omvattende verrykingsprogram vir die bevordering van die geestesgesondheid

    Directory of Open Access Journals (Sweden)

    Antoinette Gmeiner

    1997-12-01

    Full Text Available In Suid-Afrika, met die snelle veranderinge in die politiek, ekonomie, lewenstyl en tegnologiese vooruitgang, gepaard met die geweld tans in die land, is die lewenskwaliteit van mense so bemvloed dat produktiwiteit en gedrag benadeel is. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.

  6. Etíese perspektiewe vir die bantering van konflik in die mediese ...

    African Journals Online (AJOL)

    mits versagtende omstandighede nie aangevoer kan word nie. Die howe oefen dan ook alleen sy regterlike funksie uit oor 'n konkrete geskil wat van daadwerklike belang vir die werklike partye is (Strauss 1982:14). Die hof laat hom lei deur die maatstaf van goeie sedes, die boni mores. Regter Mostert se verduideliking in ...

  7. ontwikkeling van die gemenereg in die lig van artikels 39(2)

    African Journals Online (AJOL)

    Administrator

    'n Mens kan met reg vra of die ius connubiorum van Brouwer en die Law of. Husband and Wife van ... AD 560 (Geheime Raad) 563. 5 Sien vir besonderhede Hahlo en Kahn SA Legal System and its Background 304. ..... Die Franse chemikus, Antoine Lavoisier, is in 1794 tydens die Franse revolusie tereggestel. Terwyl die ...

  8. Die wonders in Johannes 6 verklaar aan die hand van 'n ...

    African Journals Online (AJOL)

    Maar die Evangelie van Johannes gee self 'n aanduiding van wat die intensie van die geskrif is, te wete Johannes 20: 30-31: Jesus het nog baie ander wondertekens, wat nie in hierdie boek beskrywe is nie, voor sy dissipels gedoen. Maar hierdie wonder tekens is beskrywe sodat julle kan glo dat Jesus die Christus is, die.

  9. How Tycho Brahe really died

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland; Petersen, Lars

    2001-01-01

    In 2001 we commemorate the 4th centenary of the death of Tycho Brahe, perhaps the first great scientists in a modern sense.This famous Danish astronomer died in Prague on the 24th of October 1601, eleven days after he had attended a banquet at the Bohemian count of Rosenberg. Tycho was too courte...

  10. Die Suche nach den Gottesteilchen

    CERN Multimedia

    2007-01-01

    2008 wird der größte jemals gebaute Teilchenbeschleuniger in Betrieb genommen Anlässlich des Mathematik-Jahres 2008 hat der Experimentalphysiker der Universität Hamburg und der designierte Generaldirektor des europäischen Zentrums für Teilchenphysik CERN in Genf, Rolf-Dieter Heuer, die Bedeutung des Dialogs zwischen Naturwissenschaftlern und Philosophen hervorgehoben.

  11. When a major star dies

    International Nuclear Information System (INIS)

    Joubert, G.

    1988-01-01

    Astrologers are slowly learning what happens when a star dies. On the night of 23-24 February 1987, the light of an exploding star - a supernova with the name SN 1987A - reached the earth. In this article this astrological event of the century are discussed, and its importance for astrologers

  12. polisemie in die woordeboek - 'n

    African Journals Online (AJOL)

    mous items, the problem of monosemic prototype categories vs. polysemous prototype categories, ...... bv. te make met kulturele norme vir die drink van warm vloeistowwe. ..... (en nie bv. teen ander soorte water of ander soorte chemiese middele nie) gede- ...... INLIGTING VERSKAF TE WORD (EN VERW AG DIT AS SODA-.

  13. Die verhouding tussen kerk en staat: Enkele modelle met verwysing ...

    African Journals Online (AJOL)

    ook ingaan op die vraag na die reg tot opstand teen die gesag van die staat soos dit in hierdie modelle beantwoord word. Ons wil eindig by die vraag na 'n teologiese model wat geskik is vir ons dag. 1. DIE TEOLOGIESE MODEL VAN DIE ROOMS-KATOLIEKE. KERK. Die Rooms-Katolieke Kerk se opvatting word bepaal ...

  14. die rol van kleurlinge in suid afrika se militere verlede

    African Journals Online (AJOL)

    die geval, want hierdie volks- groep het 'n lang en kleurryke historiese verbin- tenis met die miltere verlede van Suid-Afrika. Die feit dat die Kleurlinge nou op die drumpel staan van 'n nuwe tydvak in die staatkundige ontwikke- ling van die Republiek van Suid-Afrika, beteken ook nie dat hulle vir die eerste maal ten nouste.

  15. Acute genitourinary toxicity after high-dose-rate (HDR) brachytherapy combined with hypofractionated external-beam radiation therapy for localized prostate cancer: Correlation between the urethral dose in HDR brachytherapy and the severity of acute genitourinary toxicity

    International Nuclear Information System (INIS)

    Akimoto, Tetsuo; Ito, Kazuto; Saitoh, Jun-ichi; Noda, Shin-ei; Harashima, Koichi; Sakurai, Hideyuki; Nakayama, Yuko; Yamamoto, Takumi; Suzuki, Kazuhiro; Nakano, Takashi; Niibe, Hideo

    2005-01-01

    Purpose: Several investigations have revealed that the α/β ratio for prostate cancer is atypically low, and that hypofractionation or high-dose-rate (HDR) brachytherapy regimens using appropriate radiation doses may be expected to yield tumor control and late sequelae rates that are better or at least as favorable as those achieved with conventional radiation therapy. In this setting, we attempted treating localized prostate cancer patients with HDR brachytherapy combined with hypofractionated external beam radiation therapy (EBRT). The purpose of this study was to evaluate the feasibility of using this approach, with special emphasis on the relationship between the severity of acute genitourinary (GU) toxicity and the urethral dose calculated from the dose-volume histogram (DVH) of HDR brachytherapy. Methods and Materials: Between September 2000 and December 2003, 70 patients with localized prostate cancer were treated by iridium-192 HDR brachytherapy combined with hypofractionated EBRT at the Gunma University Hospital. Hypofractionated EBRT was administered in fraction doses of 3 Gy, three times per week; a total dose of 51 Gy was delivered to the prostate gland and the seminal vesicles using the four-field technique. No elective pelvic irradiation was performed. After the completion of EBRT, all the patients additionally received transrectal ultrasonography (TRUS)-guided HDR brachytherapy. The fraction size and the number of fractions in HDR brachytherapy were prospectively changed, whereas the total radiation dose for EBRT was fixed at 51 Gy. The fractionation in HDR brachytherapy was as follows: 5 Gy x 5, 7 Gy x 3, 9 Gy x 2, administered twice per day, although the biologic effective dose (BED) for HDR brachytherapy combined with EBRT, assuming that the α/β ratio is 3, was almost equal to 138 in each fractionation group. The planning target volume was defined as the prostate gland with 5-mm margin all around, and the planning was conducted based on

  16. Dosimetric measurements of an 192Ir HDR source with a diamond detector

    International Nuclear Information System (INIS)

    Rustgi, Surendra N.

    1996-01-01

    Purpose: To study the feasibility of using a diamond detector for the dosimetry of a high dose rate (HDR) 192 Ir source and to compare the measurement results with published data and calculations from a commercial treatment planning system. Materials and methods: The sensitive volume of the diamond detector consists of a disk of 0.26 mm thickness and 3 mm diameter. The detector was applied an external bias of +100 V and was preirradiated to a dose of 500 cGy to stabilize its response. The 192 Ir source from the Nucletron microSelectron unit has an active diameter of 0.6 mm and a length of 3.5 mm. Photon fluence anisotropy factors in air were measured at distances of 5 and 10 cm from two sources and compared with TLD measurements. Dose profiles and isodose distributions were measured at several distances from the source and compared with calculations from a Nucletron treatment planning system. These dose calculations in water use a point source approximation with the anisotropy factors independent of the radial distance from the source. Results: The photon fluence around the 192 Ir HDR source, measured with a diamond detector at distances of 5 and 10 cm from the source, is very anisotropic. Compared to the source transverse direction, the photon fluence intensity along the source axis reduces to approximately 60%. Measurements performed on two sources indicate that the photon anisotropy does not change with distance in air. Within experimental uncertainty, similar results were obtained with TLD rods and are in excellent agreement with published anisotropy factors 1 . Dose profiles, measured with the diamond detector in a water phantom, at distances of 1,2,3 and 5 cm from the source, are found to be in excellent agreement with the Nucletron planning system calculations. Similar excellent agreement is observed between the measured and calculated isodose curves in planes parallel to the source plane. Conclusion: The diamond detector has been demonstrated to be suitable

  17. NPIP: A skew line needle configuration optimization system for HDR brachytherapy

    International Nuclear Information System (INIS)

    Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtürk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean

    2012-01-01

    Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the final needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, δ. The candidate needle set consisted of 5000 needles, and a range of δ values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of δ values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many or fewer

  18. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc, E-mail: Luc.Beaulieu@phy.ulaval.ca [Département de physique, de génie physique et d’optique et Centre de recherche sur le cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Binnekamp, Dirk [Integrated Clinical Solutions and Marketing, Philips Healthcare, Veenpluis 4-6, Best 5680 DA (Netherlands)

    2015-03-15

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

  19. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    International Nuclear Information System (INIS)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk

    2015-01-01

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora ® Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators

  20. Die stand van wiskundeonderwys in Afrikaanse skole

    Directory of Open Access Journals (Sweden)

    Gerrit Stols

    2012-03-01

    Full Text Available Hoërordedenkvaardighede is noodsaaklike basiese vaardighede vir die een-en-twintigste eeu aangesien rekenaars berekeninge en algoritmes baie vinniger en akkurater kan doen as mense. Dit beteken dat skole leerders moet toerus om logies te dink, patrone te ontdek, bewyse te lewer, asook om nieroetineprobleme op te los. Hierdie fasette wat as hoërordedenke geklassifiseer word, is die kern van wiskundige denke en ontwikkeling. Suid-Afrika neem aan verskeie internasionaal vergelykende studies deel. Met behulp van hierdie vergelykende studies kan bepaal word hoe die Afrikaanse wiskundeleerders in Suid-Afrika se prestasie met dié van leerders in ander lande vergelyk en ook wat die tekortkominge in die wiskundeonderwys is. Volgens die 2003-TIMSS-uitslae is die probleem in Afrikaanse skole juis dié vrae wat hoërordedenke vereis. Dit beteken dat die Afrikaanse skole ’n doelbewuste poging sal moet aanwend om hoërordedenke te ontwikkel. Die 1999-TIMSS-videostudie toon dat die lande wat die beste presteer, soos Japan, tydens onderrig meer tyd wy aan die ontwikkeling van begripsvorming en aan die oplos van moeiliker probleme. Die fokus in die presterende lande is op die ontwikkeling van hoërordedenke deur probleemoplossing. Daar word dus minder tyd afgestaan aan herhaling van roetine- of soortgelyke oefeninge wat ’n rekenaar ook kan doen. Die omgekeerde hiervan is ’n tipiese verskynsel in Afrikaanse skole, waar ’n onderwyser byvoorbeeld een of meer voorbeelde op die bord doen waarna die leerders ’n hele aantal soortgelyke roetine-oefeninge doen.

  1. A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh

    Directory of Open Access Journals (Sweden)

    Naheed Rukhsana

    2011-07-01

    Full Text Available Purpose: The report presents an extraordinary synthesis of customer acceptance procedures (CAP, quality assurance tests (QA in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit® in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1 the deviation between specified and measured source strength: ± 3%; 2 the positional accuracy and uniformity: ± 1 mm; 3 the temporal accuracy (i.e. timer error and linearity and end error: ± 1% or 30 sec.; 4 treatment planning system (digitizer and localization software: ± 3% or 1 mm; 5 the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm. Material and methods: Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2% and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy to a point P, at a distance of “r” in centimeters from a source of the Reference Air Kerma Rate (RAKR has been utilized for the QA of the source, where source strength measurement was accomplished. Results: All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in

  2. A multicentre audit of HDR/PDR brachytherapy absolute dosimetry in association with the INTERLACE trial (NCT015662405)

    Science.gov (United States)

    Díez, P.; Aird, E. G. A.; Sander, T.; Gouldstone, C. A.; Sharpe, P. H. G.; Lee, C. D.; Lowe, G.; Thomas, R. A. S.; Simnor, T.; Bownes, P.; Bidmead, M.; Gandon, L.; Eaton, D.; Palmer, A. L.

    2017-12-01

    A UK multicentre audit to evaluate HDR and PDR brachytherapy has been performed using alanine absolute dosimetry. This is the first national UK audit performing an absolute dose measurement at a clinically relevant distance (20 mm) from the source. It was performed in both INTERLACE (a phase III multicentre trial in cervical cancer) and non-INTERLACE brachytherapy centres treating gynaecological tumours. Forty-seven UK centres (including the National Physical Laboratory) were visited. A simulated line source was generated within each centre’s treatment planning system and dwell times calculated to deliver 10 Gy at 20 mm from the midpoint of the central dwell (representative of Point A of the Manchester system). The line source was delivered in a water-equivalent plastic phantom (Barts Solid Water) encased in blocks of PMMA (polymethyl methacrylate) and charge measured with an ion chamber at 3 positions (120° apart, 20 mm from the source). Absorbed dose was then measured with alanine at the same positions and averaged to reduce source positional uncertainties. Charge was also measured at 50 mm from the source (representative of Point B of the Manchester system). Source types included 46 HDR and PDR 192Ir sources, (7 Flexisource, 24 mHDR-v2, 12 GammaMed HDR Plus, 2 GammaMed PDR Plus, 1 VS2000) and 1 HDR 60Co source, (Co0.A86). Alanine measurements when compared to the centres’ calculated dose showed a mean difference (±SD) of  +1.1% (±1.4%) at 20 mm. Differences were also observed between source types and dose calculation algorithm. Ion chamber measurements demonstrated significant discrepancies between the three holes mainly due to positional variation of the source within the catheter (0.4%-4.9% maximum difference between two holes). This comprehensive audit of absolute dose to water from a simulated line source showed all centres could deliver the prescribed dose to within 5% maximum difference between measurement and calculation.

  3. A comprehensive study on HDR brachytherapy treatments of cervical cancers: using the first Co-60 BEBIG Multisource Unit in Bangladesh.

    Science.gov (United States)

    Malik, Sadiq R; Banu, Parvin A; Rukhsana, Naheed

    2011-06-01

    The report presents an extraordinary synthesis of customer acceptance procedures (CAP), quality assurance tests (QA) in the treatment of cervical cancer patients, using the first Co-60 Multisource Unit ® in Bangladesh. The QA and commissioning required measurements and emergency tests verifying the functional limits of parameters acceptable for the new HDR afterloader. Acceptable limits were: 1) the deviation between specified and measured source strength: ± 3%; 2) the positional accuracy and uniformity: ± 1 mm; 3) the temporal accuracy (i.e. timer error and linearity and end error): ± 1% or 30 sec.; 4) treatment planning system (digitizer and localization software): ± 3% or 1 mm; 5) the distance from line to first dwell position and all the others: 5 mm and 10 mm (± 1 mm). Till February 2011, 47 patients were treated with HDR with more than 140 insertions applied. Amongst them, 12 patients were in stage IIB and IIIB, 22 were postoperative (IA and IB) while the remaining 13 patients were with unknown stage. All the cases with stage IIB and IIIB received concurrent chemo-radiation and brachytherapy. Postoperative patients received EBRT (50 Gy and HDR) according to the institutional protocol. CT scans were completed before HDR-plus planning with a good reproducibility (± 2%) and were documented in repeating the plan for the same set up of a patient. Absorbed dose (Gy) to a point P, at a distance of "r" in centimeters from a source of the Reference Air Kerma Rate (RAKR) has been utilized for the QA of the source, where source strength measurement was accomplished. All methods and analysis applicable to the QA and commissioning of Co-60 have been investigated and systematically analyzed, measured and documented before the treatment of a patient. Studies and safety requirements of this HDR remote afterloader were carried out. Acceptance and the QA were imperative to justify functionality and dependability in delivering the treatment. Implications of these studies

  4. Die naslaanpotensiaal van lemmakandidate vir ʼn ...

    African Journals Online (AJOL)

    Kate H

    Afrikaans-woordeboek in die gedrukte medium plaas welbekende tradisionele beperkinge op die leksikograaf, waarvan die vernaamste dié op ruimte is. Gegee die konteks, teikengebruiker, gebruikersituasie en funksie van die woordeboek moet ...

  5. a studyof faecal of faecal coliform die coliform die coliform die-off

    African Journals Online (AJOL)

    eobe

    COLIFORM DIE-OFF IN SEWAGE SLUDGE DRYING BED. OFF IN SEWAGE SLUDGE ..... This method was used to measure evaporation from the bed because of .... thermometer with external sensor probe, model No. ST-9283A/B/C and a ...

  6. Die spel van assosiasies in en om 'Die verlossing van die beeld' van Breyten Breytenbach

    Directory of Open Access Journals (Sweden)

    P.A. du Toit

    2005-07-01

    Full Text Available The play of association in and around 'The liberation of the image' by Breyten Breytenbach This analysis focuses on the conjunction of memory and imagination, which is an important impulse in, and key to, Breytenbach’s work. The play with language and with associations, the foregrounding, in the short story, “Die verlossing van die beeld” (Breytenbach, 1983 with its metafictional title and apparently divergent motifs (rain/water, watch, onion, the death and burial of a grandfather acts, as it were, as an invitation to the reader to become a co-player. The reader ventures on a search for traces, intertextual links within the Breytenbach oeuvre and for already acknowledged influences such as Surrealism (which in turn casts some light on the strange title of the story and the Eastern philosophies such as Zen and the even older Taoism. The analysis also takes into account the context in which “Mouroir” was written, namely Breytenbach’s term in prison (1975-1982. Seeing that the writer had to hand in his manuscripts to the jail authorities regularly, he might have decided, consciously or by intuition, to hide some thoughts and feelings behind a screen or a mask, in, for example in “Die verlossing van die beeld”, a lighter tone and irony.

  7. Die Romeinse nastrewing van onsterflikheid deur middel van memoria

    Directory of Open Access Journals (Sweden)

    D. R. Fouché

    1985-05-01

    Full Text Available Benewens die omvangryke en nasionale manifestasies van die oorspronklike onsterflikheidsgedagte in die Romeinse gemeenskap, vind ons by die Romein op kleiner skaal in groepe of indiwidueel ’n strewe na onsterflikheid langs die weg van memoria. Soos aangetoon sal word, verskil die pogings van die verskillende groepe radikaal van mekaar, hoewel die strewe en einddoel dieselfde bly, naamlik om deur die daarstelling van memoria op die gebied van woord of daad onsterflikheid te bekom.

  8. HDR-investigations of check valve closure and resultant water hammer effects

    International Nuclear Information System (INIS)

    Scholl, K.D.

    1983-01-01

    The presented investigations are based on the Loss of Coolant Accident (LOCA). They concentrate on the first blowdown phase after pipe break of a feedwater line. The effect of such a break is moderated by quick closing check valves, by which the loss of coolant water is reduced and optimal post accident conditions are obtained. Unfortunately the closure of the valve can cause high pressure peaks (water hammer effects) in the feedwater system which potentially could produce safety relevant secondary damage. The system loading by these effects has been analysed. The HDR-Investigation-results led to an improvement of the feedwater system safety by verifying damping measures of quick closing check valves. Pressure peaks obtained with undamped valves in the range of 300 bars, are reduced to zero or a few bars above the normal operation pressure in feedwater systems. For the analytical simulation of valve closure the following dominant acting forces are identified: the blowdown flow resistance of the valve cone and the damping pistong force. The analytical description and quantification of the forces depends on blowdown flow and valve friction parameters. These have been evaluated and are presented for practical use. (orig.)

  9. A summary of the Fire Testing Program at the German HDR Test Facility

    International Nuclear Information System (INIS)

    Nowlen, S.P.

    1995-11-01

    This report provides an overview of the fire safety experiments performed under the sponsorship of the German government in the containment building of the decommissioned pilot nuclear power plant known as HDR. This structure is a highly complex, multi-compartment, multi-level building which has been used as the test bed for a wide range of nuclear power plant operation safety experiments. These experiments have included numerous fire tests. Test fire fuel sources have included gas burners, wood cribs, oil pools, nozzle release oil fires, and cable in cable trays. A wide range of ventilation conditions including full natural ventilation, full forced ventilation, and combined natural and forced ventilation have been evaluated. During most of the tests, the fire products mixed freely with the full containment volume. Macro-scale building circulation patterns which were very sensitive to such factors as ventilation configuration were observed and characterized. Testing also included the evaluation of selective area pressurization schemes as a means of smoke control for emergency access and evacuation stairwells

  10. Commissioning and quality assurance procedures for the HDR Valencia skin applicators

    Directory of Open Access Journals (Sweden)

    Domingo Granero

    2016-11-01

    Full Text Available The Valencia applicators (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden are cup-shaped tungsten applicators with a flattening filter used to collimate the radiation produced by a high-dose-rate (HDR 192 Ir source, and provide a homogeneous absorbed dose at a given depth. This beam quality provides a good option for the treatment of skin lesions at shallow depth (3-4 mm. The user must perform commissioning and periodic testing of these applicators to guarantee the proper and safe delivery of the intended absorbed dose, as recommended in the standards in radiation oncology. In this study, based on AAPM and GEC-ESTRO guidelines for brachytherapy units and our experience, a set of tests for the commissioning and periodic testing of the Valencia applicators is proposed. These include general considerations, verification of the manufacturer documentation and physical integrity, evaluation of the source-to-indexer distance and reproducibility, setting the library plan in the treatment planning system, evaluation of flatness and symmetry, absolute output and percentage depth dose verification, independent calculation of the treatment time, and visual inspection of the applicator before each treatment. For each test, the proposed methodology, equipment, frequency, expected results, and tolerance levels (when applicable are provided.

  11. Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, E.; Sosa, M. A.; Gil V, A. [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Av. Insurgentes 2354, 37150 Leon, Guanajuato (Mexico); Monzon, E., E-mail: eric_1985@fisica.ugto.mx [IMSS, Unidad Medica de Alta Especialidad No. 1, Av. Adolfo Lopez Mateos 1813, 37340 Leon, Guanajuato (Mexico)

    2015-10-15

    Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

  12. Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

    International Nuclear Information System (INIS)

    Reyes, E.; Sosa, M. A.; Gil V, A.; Monzon, E.

    2015-10-01

    Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

  13. An in vivo investigative protocol for HDR prostate brachytherapy using urethral and rectal thermoluminescence dosimetry

    International Nuclear Information System (INIS)

    Toye, Warren; Das, Ram; Kron, Tomas; Franich, Rick; Johnston, Peter; Duchesne, Gillian

    2009-01-01

    Purpose: To develop an in vivo dosimetry based investigative action level relevant for a corrective protocol for HDR brachytherapy boost treatment. Methods and materials: The dose delivered to points within the urethra and rectum was measured using TLD in vivo dosimetry in 56 patients. Comparisons between the urethral and rectal measurements and TPS calculations showed differences, which are related to the relative position of the implant and TLD trains, and allowed shifts of implant position relative to the prostate to be estimated. Results and conclusions: Analysis of rectal dose measurements is consistent with implant movement, which was previously only identified with the urethral data. Shift corrected doses were compared with results from the TPS. Comparison of peak doses to the urethra and rectum has been assessed against the proposed corrective protocol to limit overdosing these critical structures. An initial investigative level of 20% difference between measured and TPS peak dose was established, which corresponds to 1/3 of patients which was practical for the caseload. These patients were assessed resulting in corrective action being applied for one patient. Multiple triggering for selective investigative action is outlined. The use of a single in vivo measurement in the first fraction optimizes patient benefit at acceptable cost.

  14. Intraoperative HDR brachytherapy for rectal cancer using a flexible intraoperative template: standard plans versus individual planning

    International Nuclear Information System (INIS)

    Kolkman-Deurloo, Inger-Karine K.; Nuyttens, Joost J.; Hanssens, Patrick E.J.; Levendag, Peter C.

    2004-01-01

    HDR intraoperative brachytherapy (IOBT) is applied to locally advanced rectal tumors using a 5 mm thick flexible intraoperative template (FIT). To reduce the procedure time, treatment planning is performed using standard plans that neglect the curvature of the FIT. We have calculated the individual treatment plan, based on the real geometry of the FIT, and the dose at clips placed during surgery. A mean treatment dose of 9.55±0.21 Gy was found for the individual plan, compared to the prescribed 10 Gy (P<0.0001). The mean central dose was 10.03±0.10 Gy in the standard plan and 9.20±0.32 Gy in the individual plan (P<0.0001). The mean dose at the corners of the FIT was 10.3 Gy in the standard plan and ranged between 10.3 and 10.5 Gy in the individual plan. In 63% of the clips, the dose was larger than 15.0 Gy, which is equivalent to a gap between the FIT and the target smaller than 5 mm. In 18% of the clips, the dose was smaller than 13.0 Gy indicating that locally the gap was larger than 5 mm. Clinical practice will have to prove if these small dose deviations influence the clinical outcome

  15. SHAM: High-level seismic tests of piping at the HDR

    International Nuclear Information System (INIS)

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J.; Malcher, L.; Schrammel, D.; Steinhilber, H.; Costello, J.F.

    1988-01-01

    As part of the second phase of vibrational/earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, high-level simulated seismic tests (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) in-plant piping system with two servohydraulic actuators, each capable of generating 40 tons of force. The purpose of these experiments was to study the behavior of piping subjected to seismic excitation levels that exceed design levels manifold and may result in failure/plastification of pipe supports and pipe elements, and to establish seismic margins for piping and pipe supports. The performance of six different dynamic pipe support systems was compared in these tests and the response, operability, and fragility of dynamic supports and of a typical US gate valve were investigated. Data obtained in the tests are used to validate analysis methods. Very preliminary evaluations lead to the observation that, in general, failures of dynamic supports (in particular snubbers) occur only at load levels that substantially exceed the design capacity. Pipe strains at load levels exceeding the design level threefold are quite small, and even when exceeding the design level eightfold are quite tolerable. Hence, under seismic loading, even at extreme levels and in spite of multiple support failures, pipe failure is unlikely. 5 refs., 16 figs

  16. Multiobjective anatomy-based dose optimization for HDR-brachytherapy with constraint free deterministic algorithms

    International Nuclear Information System (INIS)

    Milickovic, N.; Lahanas, M.; Papagiannopoulou, M.; Zamboglou, N.; Baltas, D.

    2002-01-01

    In high dose rate (HDR) brachytherapy, conventional dose optimization algorithms consider multiple objectives in the form of an aggregate function that transforms the multiobjective problem into a single-objective problem. As a result, there is a loss of information on the available alternative possible solutions. This method assumes that the treatment planner exactly understands the correlation between competing objectives and knows the physical constraints. This knowledge is provided by the Pareto trade-off set obtained by single-objective optimization algorithms with a repeated optimization with different importance vectors. A mapping technique avoids non-feasible solutions with negative dwell weights and allows the use of constraint free gradient-based deterministic algorithms. We compare various such algorithms and methods which could improve their performance. This finally allows us to generate a large number of solutions in a few minutes. We use objectives expressed in terms of dose variances obtained from a few hundred sampling points in the planning target volume (PTV) and in organs at risk (OAR). We compare two- to four-dimensional Pareto fronts obtained with the deterministic algorithms and with a fast-simulated annealing algorithm. For PTV-based objectives, due to the convex objective functions, the obtained solutions are global optimal. If OARs are included, then the solutions found are also global optimal, although local minima may be present as suggested. (author)

  17. Observing and characterizing avalanche activity in the Khumbu Himal, Nepal, using Pleiades and airborne HDR imagery

    Science.gov (United States)

    Thompson, Sarah; Nicholson, Lindsey; Klug, Christoph; Rieg, Lorenzo; Sailer, Rudolf; Bucher, Tilman; Brauchle, Jörg

    2017-04-01

    In the high, steep terrain of the Khumbu Himal, Nepal, snow avalanches play an important role in glacier mass balance, and rockfall supplies much of the rock material that forms the extensive debris covers on glaciers in the region. Information on the frequency and size of gravitational mass movements is helpful for understanding current and future glacier behaviour but currently lacking. In this study we use a combination of high resolution Pleiades optical satellite imagery in conjunction with airborne HDR imagery of slopes in deep shadow or overexposed snow slopes, provided by the German Aerospace Center (DLR) MACS system (see Brauchle et al., MM3.2/GI2.12/GMPV6.4/HS11.13/NH8.9/SSS12.24), to undertake a qualitative observational study of the gravitational processes evident in these sets of imagery. We classify the features found and discuss their likely frequency in the context of previously published research findings. Terrain analysis based upon digital terrain models derived from the same Pleiades imagery is used to investigate the slope angle, degree of confinement, curvature and aspect of observed avalanche and rock fall tracks. This work presents a first overview of the types of gravitational slides affecting glaciers of the Khumbu Himal. Subsequent research efforts will focus on attempting to quantify volumes of mass movement using repeat satellite imagery.

  18. Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities

    International Nuclear Information System (INIS)

    Pujades, M C; Granero, D; Vijande, J; Ballester, F; Perez-Calatayud, J; Papagiannis, P; Siebert, F A

    2014-01-01

    In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for 192 Ir and 60 Co HDR applications to account for several different bunker layouts. For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by 192 Ir and 60 Co will reduce the lead thickness by a factor of five for 192 Ir and ten for 60 Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers. The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness. (paper)

  19. Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities.

    Science.gov (United States)

    Pujades, M C; Granero, D; Vijande, J; Ballester, F; Perez-Calatayud, J; Papagiannis, P; Siebert, F A

    2014-12-01

    In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for (192)Ir and (60)Co HDR applications to account for several different bunker layouts.For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by (192)Ir and (60)Co will reduce the lead thickness by a factor of five for (192)Ir and ten for (60)Co. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers.The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.

  20. Characterization of commercial MOSFET detectors and their feasibility for in-vivo HDR brachytherapy.

    Science.gov (United States)

    Phurailatpam, Reena; Upreti, Rituraj; Nojin Paul, Siji; Jamema, Swamidas V; Deshpande, Deepak D

    2016-01-01

    The present study was to investigate the use of MOSFET as an vivo dosimeter for the application of Ir-192 HDR brachytherapy treatments. MOSFET was characterized for dose linearity in the range of 50-1000 cGy, depth dose dependence from 2 to 7 cm, angular dependence. Signal fading was checked for two weeks. Dose linearity was found to be within 2% in the dose range (50-1000 cGy). The response varied within 8.07% for detector-source distance of 2-7 cm. The response of MOSFET with the epoxy side facing the source (0 degree) is the highest and the lowest response was observed at 90 and 270 degrees. Signal was stable during the study period. The detector showed high dose linearity and insignificant fading. But due to angular and depth dependence, care should be taken and corrections must be applied for clinical dosimetry. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  1. Clinical implementation of a quality assurance program in HDR brachytherapy by in vivo dosimetry with diodes

    International Nuclear Information System (INIS)

    Alecu, R.; Feldmeier, J.J.; Court, W.S.; Alecu, M.; Orton, C.G.

    1996-01-01

    Despite the possibilities of in vivo dosimetry with diodes (e.g. control of dose to organs at risk, recorded confirmational measurements of the dose actually delivered, check of the whole treatment chain, avoidance of misadministrations, etc.) and the fact that it has proven to be very useful as part of a departmental QA program in external beam therapy, few attempts to implement it for HDR brachytherapy procedures have been reported. The reason for this is probably that there are significant technical challenges that must be met prior to its clinical use. The purpose of this study is to investigate the practicability and usefulness of dose measurements for brachytherapy patients in daily clinical practice. In our clinic a high precision patient dosimetry method has been developed, based on the use of silicon diodes. First, calibration factors have been determined under 'reference' irradiation conditions. Secondly, correction factors have been evaluated for situations deviating from the reference conditions, i.e. for different distances from the implanted sources, tissue heterogeneities, presence of different type of applicators, etc. For certain intracavitary, interstitial and surface mold applications this procedure has proven to be sufficiently accurate to allow dose determinations with diodes to be in good agreement with the expected values, i.e. calculated by the treatment planning system (VariSource unit) and checked by ion chamber measurements. The results of in vivo measurements are discussed along with the possibilities and limitations of the employed techniques

  2. High-level seismic tests of piping at the HDR [Heissdampfreaktor

    International Nuclear Information System (INIS)

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J.; Costello, J.F.

    1989-01-01

    As part of the second-phase testing at the Heissdampfreaktor (HDR) Test Facility in Kahl/Main, Federal Republic of Germany (FRG), high-level seismic experiments, designated SHAM, were performed on an in-plant piping system during the period of 19 April to 27 May 1988. The objectives of the SHAM experiments were to (1) study the response of piping subjected to seismic excitation levels that exceed design levels manifold and which may result in failure/plastification of pipe supports and pipe elements; (2) provide data for the validation of linear and nonlinear pipe response analyses; (3) compare and evaluate, under identical loading conditions, the performance of various dynamic support system, ranging from very flexible to very stiff support configurations; (4) establish seismic margins for piping, dynamic pipe supports, and pipe anchorages; and (5) investigate the response, operability, and fragility of dynamic supports and of a typical US gate valve under extreme levels of seismic excitation. A brief description of the SHAM tests is provided, followed by highlights of the test results that are given primarily in the form of maximum response values. Also presented are very limited comparisons of experimental data and pretest analytical predictions. 6 refs., 8 figs

  3. Full-scale HDR blowdown experiments as a tool for investigating dynamic fluid-structural coupling

    International Nuclear Information System (INIS)

    Krieg, R.; Schlechtendahl, E.G.; Scholl, K.-H.; Schumann, U.

    1977-01-01

    As an answer to rigorous safety requirements in reactor technology an experimental-theoretical program has been established to investigate safety-relevant mechanical aspects of LWR-blowdown accidents. Part of the program are several full-scale blowdown experiments which will be performed in the former HDR-reactor. As the conceptional study confirms, the primary goal is to find out, how big the safety margins of present LWR's in the case of a blowdown actually are, rather than simply to show that essential parts of the reactor will withstand such an accident. However, to determine the safety margins, the physical phenomena involved in the blowdown process must be understood and appropriate wave of description must be found. Therefore the experimental program is accompanied by the development of theoretical models and computer codes. A survey is given over existing methods for coupled fluid structural dynamics. The following approaches are used: - Specific finite difference-code for integrated treatment of both fluid and structure in 3D-geometry using the fast cyclic reduction scheme for solving Poisson's equation. - Modification of mass and stiffness matrices of FEM-models for shell dynamics by reducing the 3D incompressible fluid problem to 2D with the boundary integral equation method. This presently developed method has the capacity to deal with general problems in fluid-structural coupling. (Auth.)

  4. Large scale fire experiments in the HDR containment as a basis for fire code development

    International Nuclear Information System (INIS)

    Hosser, D.; Dobbernack, R.

    1993-01-01

    Between 1984 and 1991 7 different series of large scale fire experiments and related numerical and theoretical investigations have been performed in the containment of a high pressure reactor in Germany (known as HDR plant). The experimental part included: gas burner tests for checking the containment behaviour; naturally ventilated fires with wood cribs; naturally and forced ventilated oil pool fires; naturally and forced ventilated cable fires. Many results of the oil pool and cable fires can directly be applied to predict the impact of real fires at different locations in a containment on mechanical or structural components as well as on plant personnel. But the main advantage of the measurements and observations was to serve as a basis for fire code development and validation. Different types of fire codes have been used to predict in advance or evaluate afterwards the test results: zone models for single room and multiple room configurations; system codes for multiple room configurations; field models for complex single room configurations. Finally, there exist codes of varying degree of specialization which have proven their power and sufficient exactness to predict fire effects as a basis for optimum fire protection design. (author)

  5. Professionalisme met verwysing na die posisie van bedryfsielkunde en die bedryfsielkundige in Suid-Afrika

    Directory of Open Access Journals (Sweden)

    A. van der Merwe

    1981-11-01

    Bedryfsielkunde, as relatief jong maar snelgroeiende wetenskap, word aan die hand van ses kriteria vir 'n professie evalueer. Resultate in hierdie verband dui in die algemeen daarop dat die vakgebied alreeds vir 'n aantal jare in 'n oorgangsfase tot ‘n volwaardige professie is en dat daar in hierdie proses reeds ver op die professionele kontinuum gevorder is. Verdere onder-soeke ten opsigte van professionele opleiding, die statutêre organisering van Bedryfsielkunde asook 'n professionele kode en vereniging vir die Bedryfsielkunde word bepleit ten einde die professionele posisie van die vakgebied volledig te konsolideer.

  6. Killing, letting die and euthanasia.

    Science.gov (United States)

    Husak, D N

    1979-12-01

    Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible.

  7. Killing, letting die and euthanasia.

    Science.gov (United States)

    Husak, D N

    1979-01-01

    Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible. PMID:541821

  8. Die ausbildung von wertbedeutungen im schuljugendalter*

    Directory of Open Access Journals (Sweden)

    Siegfried Heusinger

    1978-12-01

    Full Text Available Die folgenden Darlegungen stützen sich auf Untersuchungsergebnisse des Verlassers zur Sprachentwicklung in der Ontogenese. Angeregt wurde die UnterSuchung durch die besonders in den letzten Jahren in mehreren Ländern verstärkt erhobenen Forderungen, nicht nur die Sprache des Klein­ kindes, sondern vornehmlich den Entwicklungsstand der Schülersprache auf den einzelnen Klassenstufen zu erforschen und den Prozeß der Sprachentwicklung des Schülers genauer zu bestimmen. Die Forderungen sind (so z. B. in der DDR durch das Bestreben motiviert, weitere wissenschaftliche Voraussetzungen für die Verbesserung der muttersprachlichen Bildung und Erzliehung zu schaffen. Es geht also vor allem um Bedürfnisse des Muttersprachunterrichts, die aus der gesellschaftlichen Bedeutung der Sprache überhaupt und den steigenden Anforderungen an die gesellschaftliche Kommunikation insbesondere erwachsen.

  9. NORMERING IN DIE AFRIKAANSE RADIO- EN TELEVISIEDIENS ...

    African Journals Online (AJOL)

    soortnaam plus soortnaam" kan albei komponente in Engels. 'n hoofletter kry, in Afrikaans slegs die eerste lid. Vergelyk Cash. Sale,. Kontantultverkoping. Uit 'n reklame-oogpunt Is die Engelse model bulgsamer, funksioneler en doelmatiger as ...

  10. [Die Gründung...] / Anders Henriksson

    Index Scriptorium Estoniae

    Henriksson, Anders

    2004-01-01

    Rets.: Karsten Brüggemann. Die Gründung der Republik Estland und das Ende des "Einen und unteilbaren Russland" : die Petrograder Front des Russischen Bürgerkrieges, 1918-1920. Wiesbaden : Harrassowitz, 2002

  11. Die uitbeelding van die vrou in Huisgenoot (1963 en 2013: ’n Multimodale diskoersanalise

    Directory of Open Access Journals (Sweden)

    Susann H. Marais

    2017-05-01

    Full Text Available Die standpunt dat die mens en die media in ’n verhouding van wedersydse beïnvloeding staan, sowel as die studie wat die kulturele konseptualisering van vroulikheid in twee Huisgenoot-uitgawes (1953 en 2003 ondersoek, geld as uitgangspunt vir dié studie. Hierdie studie het ten doel om te bepaal of daar ’n verskil is in die uitbeelding van die vrou in die Huisgenoot uitgawes van onderskeidelik 1963 en 2013. Volgens navorsing werk die visuele beeld en geskrewe teks saam om ’n boodskap oor te dra. Multimodale diskoersanalise (MDA word juis gebruik om beide visuele beeld en geskrewe teks te bestudeer. Sodoende word die metode van intersemiotiese komplementariteit binne MDA in hierdie studie gebruik. Die studie kom tot die gevolgtrekking dat die uitbeelding van die ideale vrou se verantwoordelikhede uitgebrei is, maar dat die vrou se rol tóg tot sekere ruimtes beperk word, soos die sigbaarheid van die moeder-stereotipe weerspieël.

  12. Die waarde van voorafopleiding deur die ouer vir pedo-oudiometrie by drie- en vierjarige kleuters

    Directory of Open Access Journals (Sweden)

    Merisa Lodewyckx

    1981-11-01

    Full Text Available Die verkryging van akkurate, betroubare inligting aangaande die gehoorvermoë van jong kinders is van besondere belang vir die oudioloog, maar word dikwels bemoeilik aangesien die kleuter nie goeie samewerking bied in die vreemde pedo-oudiometriese situasie nie. Die oplossing hiervoor is grootliks geleë in die opleiding van die kind voor formele  gehoortoetsing en meer spesifiek  opleiding tuis deur die ouer. Die doel van hierdie studie was om 'n voorbereidende program op te stel wat die ouer tuis met die kind kan uitvoer, voordat formele  toetsing plaasvind. Die waarde en effek van hierdie program in die pedo-oudiometriese situasie is geevalueer by 'n groep drie- en vierjarige kleuters. Resultate dui daarop dat laer en meer akkurate drempels, 'n korter toetstydperk, verminderde angs en beter samewerking verkry is by die kleuters wat vooraf  opleiding ontvang het. Die opleidingsprogram kan dus in die kliniese praktyk benut word as voorafopleiding  vir pedo-oudiometrie.

  13. Die woordeboek vir meganiese ingenieurs: Vorderingsverslag

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1990-07-01

    Full Text Available Die komitee van die Nasionale Vakterminologiediens (NVD wat ’n woordeboek vir meganiese ingenieurswese saamstel en in Januarie 1986 met sy werksaamhede begin het, maak goeie vordering. Die dag-tot-dag-werk word deur 'n redaksiekomitee behartig wat twee keer maandeliks vergader en uit verteenwoordigers van universiteite, SAVD, YSKOR, SABS en ander instansies bestaan.

  14. Die Reformdiskussion in der senegalesischen Sprachplanungs- politik

    African Journals Online (AJOL)

    Die Reformdiskussion in der senegalesischen Sprachplanungspolitik 13 hatten afrikanische Bildungspolitiker und Kulturtheoretiker (Senghor, Nkrumah, Kenyatta, etc.) sehr früh die Rolle der Sprache und Bildung in einem zukünftigen souveränen afrikanischen Staat anerkannt. Die damals geführten staatsrechtlichen ...

  15. Taalgesindhede en die onderrig van Afrikaans

    Directory of Open Access Journals (Sweden)

    Barbara Bosch

    2013-02-01

    Full Text Available In die onderrig aan en aanleer van Afrikaans deur nie-moedertaalsprekers behoort daar in 'n multi-kulturele omgewing met taalgesindhede rekening gehou te word: die taalaanleerder se gesindheid teenoor en stereotipiese sienswyses van die sprekers van die teikentaal en die teikentaal self beinvloed die sukses van die verskil/ende stadia van die aanleerproses. Hierdie beinvloeding vind plaas omdat gesindhede motivering beinvloed en as sosio-affektiewe filter in die taalaanleerproses kan optree. Die implikasies van heersende gesindhede teenoor Afrikaans vir die onderrig en aanleer van die taal in 'n multitalige situasie word indringend bespreek. In the teaching of Afrikaans to and the acquisition of the language by non-mother tongue speakers in a multi-lingual environment, cognizance should be taken of prevailing attitudes: the attitudes of the learner towards the target language and his/her stereotypical perceptions of the target language and its speakers which influence the success of the language learning process in various stages. This influence takes place because attitudes affect motivation and can also act as a socio-ajjective filter in the language acquisition process. The implications of existing attitudes towards Afrikaans for the teaching and acquisition of the language in a multi-lingual situation are discussed in depth.

  16. Die ontwerp van ʼn Afrikaanse taakgebaseerde rekenaaronderrig ...

    African Journals Online (AJOL)

    Kate H

    gelewer word, is om die moontlike ontwerp van ʼn taakgebaseerde rekenaarprogram vir die kursus. Beginner Afrikaans Vlak 1 te ... to transfer the required amount of credits back to their home universities. The Language Centre ..... 3.1.1 Die tweeledige kanaal-aanname (“dual channel assumption”). Hierdie aanname ...

  17. Leibniz und die Psychophysik des Gehirns

    NARCIS (Netherlands)

    S. Tuinen (Sjoerd)

    2011-01-01

    textabstract1. Das Gehirn als Medium allen Denkens Die Probleme der Philosophie sind laut Deleuze niemals von sich aus philosophisch. Bereits eine Antwort auf die Frage Was ist Philosophie? setzt ein nicht-philosophisches 'Bild des Denkens' voraus, eine Art absoluten Hintergrund, in den die

  18. uniform van die staatspresidentswag - herkoms en tradisie

    African Journals Online (AJOL)

    A blue uniform was inter alia proposed in 1980 but finally rejected by the Prime Minister in 1984. Instructions were issued to put forth new ideas. All the arguments in ..... In 1896 Is die rang van kommandant van die Staatsartlllerie verhoog tot die van lultenant-kolonel. Henning Pretorlus, father and first commandant of the.

  19. Straatsburg en artikel 2 van die dordtse kerkorde

    Directory of Open Access Journals (Sweden)

    L. F. Schulze

    1966-03-01

    Full Text Available In art. 2 K.O. word daar vier soorte kerklike dienste on dcrskei, nl. „dié van die bedienaars van die Woord, dié van die professore aan die teologiese skool, die van die ouderlinge, en dié van die diakens”.

  20. Die skrywer. Esta Steyn. Kaapstad: Tafelberg, 2012. 214 pp. ISBN ...

    African Journals Online (AJOL)

    ningsromans in Duits, is die Christelike ele- mente en die humor. Die straatslim Anabella wat twee plaaswerkers aansê om nie die Here se naam te misbruik nie, toon kenmerke van die heldin in 'n Afrikaanse liefdesverhaal. Hierdie roman sal byval vind by lesers wat. Esta Steyn se vorige romans geniet het. Die humor in die ...