Eine empirische Untersuchung von Kosteneinflußfaktoren bei integrationsorientierten Reengineering-Projekten

Die Zusammenhänge zwischen Merkmalen eines Software-Altsystems und den daraus resultierenden Kosten für bestimmte Reengineering-Aktivitäten sind nahezu unerforscht. Der vorliegende Arbeitsbericht schildert die experimentelle Untersuchung von drei ausgewählten Einflußfaktoren bei einer für das integrationsorientierte Reengineering typischen Aufgabenstellung. Untersucht wurden die Wirkungen der Komplexität des Quelltexts, der Dokumentiertheit der Datenstrukturen sowie der Verfügbarkeit von Tages- bzw. Testdaten

Eine empirische Untersuchung von Kosteneinflußfaktoren bei integrationsorientierten Reengineering-Projekten

Die Zusammenhänge zwischen Merkmalen eines Software-Altsystems und den daraus resultierenden Kosten für bestimmte Reengineering-Aktivitäten sind nahezu unerforscht. Der vorliegende Arbeitsbericht schildert die experimentelle Untersuchung von drei ausgewählten Einflußfaktoren bei einer für das integrationsorientierte Reengineering typischen Aufgabenstellung. Untersucht wurden die Wirkungen der Komplexität des Quelltexts, der Dokumentiertheit der Datenstrukturen sowie der Verfügbarkeit von Tages- bzw. Testdaten

An overview on extremity dosimetry in medical applications

Some activities of EURADOS Working Group 9 (WG9) are presently funded by the European Commission (CONRAD project). The objective of WG9 is to promote and co-ordinate research activities for the assessment of occupational exposures to staff at workplaces in interventional radiology (IR) and nuclear medicine. For some of these applications, the skin of the fingers is the limiting organ for individual monitoring of external radiation. Therefore, sub-group 1 of WG9 deals with the use of extremity dosemeters in medical radiation fields. The wide variety of radiation field characteristics present in a medical environment together with the difficulties in measuring a local dose that is representative for the maximum skin dose, usually with one single detector, makes it difficult to perform accurate extremity dosimetry. Sub-group 1 worked out a thorough literature review on extremity dosimetry issues in diagnostic and therapeutic nuclear medicine and positron emission tomography, interventional radiology and interventional cardiology and brachytherapy. Some studies showed that the annual dose limits could be exceeded if the required protection measures are not taken, especially in nuclear medicine. The continuous progress in new applications and techniques requires an important effort in radiation protection and trainin

An overview of the use of extremity dosemeters in some European countries for medical applications

Some medical applications are associated with high doses to the extremities of the staff exposed to ionising radiation. At workplaces in nuclear medicine, interventional radiology, interventional cardiology and brachytherapy, extremities can be the limiting organs as far as regulatory dose limits for workers are concerned. However, although the need for routine extremity monitoring is clear for these applications, no data about the status of routine extremity monitoring reported by different countries was collected and analysed so far, at least at a European level. In this article, data collected from seven European countries are presented. They are compared with extremity doses extracted from dedicated studies published in the literature which were reviewed in a previous publication. The analysis shows that dedicated studies lead to extremity doses significantly higher than the reported doses, suggesting that either the most exposed workers are not monitored, or the dosemeters are not routinely worn or not worn at appropriate position

Philosophical Performances in Everyday Life Situations

The real world of everyday life with its unfailing routines, repetitions and manifold habits may be seen as a matrix for the immanent expressions of what could holistically be called ‘The Void’, ‘The Real’ or simply ‘The all-embracing presence of immanence’. Thus, everyday life situations may tell us more than we normally assume about ourselves and the chimerical vision of an existing subject within the process of self-expression. But how can we investigate such situations in an appropriate manner, so that they show us by themselves somehow pre-reflexive patterns they incorporate? There is no unique method of how to investigate such situations; however, there should be a methodological form of performative settings beyond the stage which I would like to discuss.Following some of the ideas of Julian Klein and Arno Böhler on the significance of our feelings and on the limits of conceptual thinking I propose a specific form of philosophical performances, which is based on a grounding of emotions within thinking and on postponed deliberations within networking groups of individuals who are sharing a similar background of specific experiences in a given population

Extremity ring dosimetry intercomparison in reference and workplace fields

An intercomparison of ring dosemeters has been organised with the aim of assessing the technical capabilities of available extremity dosemeters and focusing on their performance at clinical workplaces with potentially high extremity doses. Twenty-four services from 16 countries participated in the intercomparison. The dosemeters were exposed to reference photon (137Cs) and beta (147Pm, 85Kr and 90Sr/90Y) fields together with fields representing realistic exposure situations in interventional radiology (direct and scattered radiation) and nuclear medicine (99 mTc and 18F). It has been found that most dosemeters provided satisfactory measurements of Hp(0.07) for photon radiation, both in reference and realistic fields. However, only four dosemeters fulfilled the established requirements for all radiation qualities. The main difficulties were found for the measurement of low-energy beta radiation. Finally, the results also showed a general under-response of detectors to 18F, which was attributed to the difficulties of the dosimetric systems to measure the positron contribution to the dos

Extremity exposure in nuclear medicine: preliminary results of a European study

The Work Package 4 of the ORAMED project, a collaborative project (2008-11) supported by the European Commission within its seventh Framework Programme, is concerned with the optimisation of the extremity dosimetry of medical staff in nuclear medicine. To evaluate the extremity doses and dose distributions across the hands of medical staff working in nuclear medicine departments, an extensive measurement programme has been started in 32 nuclear medicine departments in Europe. This was done using a standard protocol recording all relevant information for radiation exposure, i.e. radiation protection devices and tools. This study shows the preliminary results obtained for this measurement campaign. For diagnostic purposes, the two most-used radionuclides were considered: 99mTc and 18F. For therapeutic treatments, Zevalin® and DOTATOC (both labelled with 90Y) were chosen. Large variations of doses were observed across the hands depending on different parameters. Furthermore, this study highlights the importance of the positioning of the extremity dosemeter for a correct estimate of the maximum skin dose

To interact or not to interact:The pros and cons of including interactions in linear regression models

Interaction effects are very common in the psychological literature. However, interaction effects are typically very small and often fail to replicate. In this study, we conducted a simulation comparing the generalizability and estimability of two linear regression models: one correctly specified to account for interaction effects and one misspecified including simple effects only. We manipulated noise levels, predictor variable correlations, and different sets of regression weights, resulting in 9216 different conditions. From each dataset, we drew 1000 samples of N = 25, 50, 100, 250, 500, and 1000, resulting in a total of 55,296,000 analyses for each model. Our results show that misspecification can drastically bias regression estimates, sometimes leading to zero or reversed simple effects. Furthermore, we found that when models are generalized to the entire population, the difference between the explained variance in the sample and in the population is often smaller for the misspecified model than for the correctly specified model. However, the comparison between models shows that the correctly specified model explains the data at the population level better overall. These results emphasize the importance of theory in modeling choices and show that it is important to provide a rationale for why interactions are included or excluded in an analysis

Prevalence of occult hepatitis B virus infection in chronic haemodialysis and kidney transplant patients

Okkulte Hepatitis B Infektionen (OBI) werden definiert als die Präsenz von Hepatitis B Virus (HBV) DNA im Serum und/ oder in Hepatozyten in HBsAg-negativen Patienten. Die Prävalenz und klinische Relevanz der OBI bei Hämodialyse Patienten und Nierentransplantierten sind bisher ungeklärt, deshalb wurden sie in dieser großen Querschnittsstudie untersucht. Da es Hinweise darauf gibt, dass HBV sich auch in ext- rahepatischen Zellen befindet, wurden zusätzlich periphere mononukleäre Blutzellen (PBMC) als Untersuchungsmaterial verwendet. Methodik: Bei 417 Hämodialyse Patienten, 417 Nierentransplantierten, 20 HBsAg-posi- tive nicht-Hämodialyse und nicht-Nierentransplantierte Patienten (positiv Kontrolle) und 40 HBsAg-negativ gesunde Freiwilligen (negativ Kontrolle) wurde Serum und PBMCs mittels Polymerase-Kettenreaktion (PCR) auf HBV DNA untersucht. Ergebnisse: Hämodialyse Patienten: 41/417 wurden aufgrund fehlender anti-HBc oder HBV DNA-Bestimmung aus der Studie ausgeschlossen. 2/376 Patienten waren HBsAg- positive. Die 374 HBsAg-negativen Patienten wurden negativ auf HBV-DNA im Serum und PBMCs getestet. Nierentransplantierte Patienten: 14/417 Patienten waren HBsAg- positiv. 1/417 HBsAg-negativ Patienten wurden positiv auf HBV DNA im Serum aber nicht in PBMCs getestet. Positiv Kontrollen: 6/20 Patienten befanden sich unter antivira- ler Therapie und es wurde keine HBV-DNA im Serum und PBMCs nachgewiesen. In 11/14 Patienten, die HBsAg-positiv waren, wurde HBV-DNA im Serum, und in 3/11 im Serum und PBMCs nachgewiesen. Negativ Kontrollen: Bei 6/40 konnte anti-HBc nicht bestimmt werden. Alle verbleibenden 34 Patienten waren anti-HBc-negativ und HBV- DNA-negativ im Serum und PBMCs. In der Langzeituntersuchung zeigte der einzige anti-HBc-negative Patient mit OBI einen Verlust von anti-HBs nach 5 Jahren Studien- aufnahme und eine HBV Reaktivierung mit HBsAg Re-Serokonversion. Schlussfolgerungen: Es wurde keine Prävalenz von OBI bei Hämodialyse Patienten und eine sehr niedrige Prävalenz von unter 1% bei Nierentransplantierten nachgewie- sen, so dass die Routine-Diagnostik und Screening von HBV-DNA mittels PCR in die- sem Patientenkollektiv und der ausgewählten Region nicht nötig ist. Bei Nierentrans- plantierten sollte jedoch ein Screening auf HBV DNA vor Transplantation erfolgen. Die Untersuchung von HBV-DNA in PBMCs scheint keinen Vorteil zu haben.Introduction: Occult hepatitis B virus infection (OBI) is defined as presence of hepatitis B virus (HBV)-DNA in serum and/or liver in HBsAg-negative patients. We investigated the prevalence of OBI in large chronic hemodialysis (CHD) and kidney transplant recipients (KTxR) cohorts, including determination of HBV-DNA in peripheral blood mononuclear cells (PBMCs). Methods: HBV-DNA was determined with the PCR in both serum and PBMCs in 417 CHD patients, 417 KTxR, 20 HBsAg-positive non-CHD non-KTx patients (positive controls) and 40 HBsAg-negative healthy subjects (negative controls). Results: CHD group: 41/417 were excluded because of missing results in anti-HBc or HBV DNA. 2/376 patients were HBsAg-positive. The 374 HBsAg-negative patients were tested negative for HBV-DNA in both serum and PBMCs. KTxR group: 14/417 patients were HBsAg-positive. 1/417 HBsAg-negative patients were tested positive for HBV DNA in serum but not in PBMCs. Positive controls: 6/20 patients were under antiviral therapy and had negative HBV-DNA in both serum and PBMCs. In 11/14 remaining patients, HBV-DNA was detected in serum, and in both serum and PBMCs in 3 patients. Negative controls: In 6/40 were missing results of anti-HBc, all remaining 34 patients were anti-HBc-negative and HBV-DNA-negative in both serum and PBMCs. In the long-term, the only case of anti-HBc-negative OBI lost anti-HBs five years after inclusion in the study and showed HBV reactivation with HBsAg re-seroconversion. Conclusions: We found nil prevalence of OBI in CHD patients and a very low prevalence (<1%) in KTx recipients suggesting that testing of HBV-DNA is not required for screening and diagnosis in these populations in our region. However, in KTxR, pretransplant screening with HBV DNA should be considered. Testing for HBV-DNA in PBMCs does not seem to be of additional value

Diagnosis and Management of Iliac Artery Endofibrosis: Results of a Delphi Consensus Study

Objective Iliac endofibrosis is a rare condition that may result in a reduction of blood flow to the lower extremity in young, otherwise healthy individuals. The data to inform everyday clinical management are weak and therefore a Delphi consensus methodology was used to explore areas of consensus and disagreement concerning the diagnosis and management of patients with suspected iliac endofibrosis. Methods A three-round Delphi questionnaire approach was used among vascular surgeons, sports physicians, sports scientists, radiologists, and clinical vascular scientists with experience of treating this condition to explore diagnosis and clinical management issues for patients with suspected iliac artery endofibrosis. Analysis is based on 18 responses to round 2 and 14 responses to round 3, with agreement reported when 70% of respondents were in agreement. Results Initially there was agreement on the typical symptoms at presentation and the need for an exercise test in the diagnosis. Round 3 clarified that duplex ultrasound was a useful tool in the diagnosis of endofibrosis. There was consensus on the most appropriate type of surgery (endarterectomy and vein patch) and that endovascular interventions were inadvisable. The final round helped to inform aspects of the natural history and post-operative surveillance. Progression of the disease was likely with continued exercise but cessation may prevent progression. Surveillance after surgery is generally recommended yearly with at least a clinical assessment. Conclusions There is broad agreement about the presenting symptoms and the investigations required to confirm (or exclude) the diagnosis of iliac endofibrosis. There was consensus on the surgical approach to repair. Disagreement existed about the specific diagnostic criteria that should be applied during non-invasive testing and about post-operative care and resumption of exercise