2,099 research outputs found

    Publicness, Privacy and Confidentiality in the Single-Serving Quantum Broadcast Channel

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    The 2-receiver broadcast channel is studied: a network with three parties where the transmitter and one of the receivers are the primarily involved parties and the other receiver considered as third party. The messages that are determined to be communicated are classified into public, private and confidential based on the information they convey. The public message contains information intended for both parties and is required to be decoded correctly by both of them, the private message is intended for the primary party only, however, there is no secrecy requirement imposed upon it meaning that it can possibly be exposed to the third party and finally the confidential message containing information intended exclusively for the primary party such that this information must be kept completely secret from the other receiver. A trade-off arises between the rates of the three messages, when one of the rates is high, the other rates may need to be reduced to guarantee the reliable transmission of all three messages. The encoder performs the necessary equivocation by virtue of dummy random numbers whose rate is assumed to be limited and should be considered in the trade-off as well. We study this trade-off in the one-shot regime of a quantum broadcast channel by providing achievability and (weak) converse regions. In the achievability, we prove and use a conditional version of the convex-split lemma as well as position-based decoding. By studying the asymptotic behaviour of our bounds, we will recover several well-known asymptotic results in the literature.Comment: 23 pages, 1 figure, journa

    The South African Medicines Control Council: Comparison of Its Registration Process With Australia, Canada, Singapore, and Switzerland

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    © 2019 Keyter, Salek, Banoo and Walker.Introduction: Comparisons between regulatory authorities of similar size and regulatory characteristics facilitate value-added benchmarking and provide insight into regulatory performance. Such comparisons highlight areas for improvement as authorities move toward achieving their regulatory goals and stakeholders’ demands. The aims of this study were to compare the registration process and the regulatory review model of the South African Medicines Control Council (MCC) to that of four other similar-sized regulatory authorities and to identify areas for improvement that may inform recommendations to the South African Health Products Regulatory Authority (SAHPRA) as it looks to re-engineer and enhance the registration process in South Africa. Methods: A questionnaire describing the organisational structure, the registration process, good review and decision-making practices of the MCC was completed by the author (AK) for the purpose of this study and validated by the Registrar of the MCC. Similar questionnaires were also completed and validated by Australia’s Therapeutic Goods Administration (TGA), Canada’s Health Canada, Singapore’s Health Science Authority (HSA) and Switzerland’s Swissmedic. Results: A comparison of the MCC regulatory process with the four comparative agencies indicated that they all have similar requirements and employ a full-review model although the timelines for the MCC were considerably longer. However, similar quality measures were implemented by all authorities as part of their good review practices (GRevP) including prioritising transparency, communication, continuous improvement initiatives and training. Conclusion: Comparisons made through this study provided insight into the areas of the MCC registration process that may be improved and have informed recommendations to SAHPRA including the implementation of facilitated regulatory pathways, definition of targets for key milestones in regulatory review and formal implementation and monitoring of GRevP. In order to build quality into the review process the application of a standardised template for the clinical assessment of medicines such as the Universal Methodology for Benefit-Risk Assessment (UMBRA) could be considered as well as enhancing transparency and communication through the application of an electronic management system and the development of publicly available summaries for the basis of approval.Peer reviewedFinal Published versio

    Quality assurance program for prototype stereotactic system developed for Neptun 10 PC linac

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    Background: A prototype stereotactic radiosurgery set was designed and constructed for a Neptun 10 PC linac that is currently being used at Imam Reza hospital in Mashhad. Materials and Methods: A complete qualit y assurance program was designed and performed for the constructed system including isocentric accuracy test, localization accuracy test, dose delivery accuracy test and leakage radiation test. Target simulator, control alignment device and plexiglass phantom which were parts of the developed hardware were used to fulfill quality assurance program. Results: The average isocentric shift resulted from the gantry rotation and couch turning were respectively obtained to be 1.4 and 2 mm. The average localization error in the three coordinates was found to be 2.2 mm. The total treatment uncertainty due to all of the probable errors in the system was equal to 4.32 mm. The dose delivery accuracy test was carried out, the result indicated a 3-7% difference between the given and measured dose. Conclusion: The quality assurance tests showed consistent performance of the constructed system within the accepted limits; however, some inconsistency might exist in certain cases. The safety of SRS method is increased when the overall uncertainty is minimized and the treatment of the lesions adjacent to critical organs is avoided

    Development of head docking device for linac-based radiosurgery with a Neptun 10 PC linac

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    Stereotactic radiosurgery is a method for focused irradiation of intracranial lesions. Linac-based radiosurgery is currently performed by two techniques: couch mounted and pedestal mounted. In the first technique a device is required to affix the patient's head to the couch and moreover to translate it accurately. Structure of such a device constructed by the authors plus acceptance test performed for evaluation is described in the article. A head docking device has been designed and constructed according to geometry of linac's couch and also desired functions. The device is completely made from aluminum and consists of four major components: attachment bar, lower structure with four movements, upper structure with two movements equipped with a lock, two handles and a mounting ring for stereotactic frame. Translating accuracy, mechanical stability and isocentric accuracy were assessed in the frame of acceptance test. Translating accuracy, mechanical stability and isocentric accuracy were found to be respectively: 1 mm, 1.64 mm and 3.2 mm with accuracy of 95%. According to AAPM report no.54, a head docking device should translate head with an accuracy of 1 mm; this recommendation has been met. Moreover, we have demonstrated that the isocentric accuracy and mechanical stability of the device are sufficient that the device can confidently be used in stereotactic treatment

    Independence versus Affiliation: What Determines Entry into Parliamentary Party Groups?

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    Political parties are often considered essential for structuring parliamentary decisionmaking in democracies. However, many MPs experience spells of being non-affiliated with any parliamentary party group (PPG), either because they were elected as independent candidates or left their PPGs earlier in the legislative term. Whether such non-affiliation periods end with an entry to a PPG, which PPG the legislator enters and how long they remain independent before the entry, as well as the reasons for these patterns, remains relatively unknown. This paper addresses these under-researched questions by examining PPG entry in three Central and Eastern European countries (Lithuania, Poland, and Romania) in the last two decades. We build and test an argument that electoral, office and policy concerns of both the MPs considering the entry and the potential receiving parties play an important role in driving entry. Our findings suggest that legislators’ electoral incentives as a key explanation for their PPG affiliation decisions

    Health Technology Assessment (HTA) Case Studies : Factors Influencing Divergent HTA Reimbursement Recommendations in Australia, Canada, England, and Scotland

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    This document is the accepted manuscript version of the following article: Nicola Allen, Stuart R. Walker, Lawrence Liberti, and Sam Salek, ‘Health Technology Assessment (HTA) Case Studies: Factors Influencing Divergent HTA Reimbursement Recommendations in Australia, Canada, England, and Scotland’, Vol. 20 (3): 320-328, 2017, is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. The final, definitive version is available online at doi:https://doi.org/10.1016/j.jval.2016.10.014.OBJECTIVES: To evaluate the national regulatory, health technology assessment (HTA), and reimbursement pathways for public health care in Australia, Canada, England, and Scotland, to compare initial Canadian national HTA recommendations with the initial decisions of the other HTA agencies, and to identify factors for differing national HTA recommendations between the four HTA agencies. METHODS: Information from the public domain was used to develop a regulatory process map for each jurisdiction and to compare the HTA agencies' reimbursement recommendations. Medicines that were reviewed by all four agencies and received a negative recommendation from only one agency were selected as case studies. RESULTS: All four countries have a national HTA agency. Their reimbursement recommendations are guided by both clinical efficacy and cost-effectiveness, and the necessity for patient input. Their activities, however, vary because of different mandates and their unique political, social, and population needs. All have an implicit or explicit quality-adjusted life-year threshold. The seven divergent case studies demonstrate examples in which new medicine-indication pairs have been rejected because of uncertainties surrounding a range of factors including cost-effectiveness, comparator choice, clinical benefit, safety, trial design, and submission timing. CONCLUSIONS: The four HTA agencies selected for inclusion in this study share common factors, including a focus on clinical efficacy and cost-effectiveness in their decision-making processes. The differences in recommendations could be considered to be due to an individual agency's approach to risk perception, and the comparator choice used in clinical and cost-effectiveness studies.Peer reviewedFinal Accepted Versio

    Understanding the Complexity of Party Instability in Parliaments

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    We propose a new typology of parliamentary party switches (switching events) that focuses on three dimensions: (1) the number of MPs and the degree of coordination, (2) the origin of switchers and (3) the destination of switchers – a parliamentary party group (PPG) or independent status. We further distinguish between switches with single and multiple destinations. Our approach sheds new light to party instability in various ways. We elucidate types of party instability to emphasize the complexity of party instability that have eluded the conceptual toolset available thus far. For example, “collective defection” (coordinated movement from one PPG to another), “collective exit” (MPs exiting their parliamentary group to become independent MPs) and “multi-PPG split” (coordinated moves from several PPGs to form a new PPG). Using preliminary data compiled for Instaparty (Party Instability in Parliaments) project from (mostly) Poland and Ireland, we find rich diversity in the forms of parliamentary party instability. While individual defections are much more common than group defections, they are clearly more dominant in Ireland than in Poland; furthermore, switches between PPGs (rather than between PPGs and independent status) have been more common in Poland. Our typology is illustrated by the analysis of the 8th Polish Sejm that provides examples of nearly all single-origin switching events and of most multiorigin ones. The new typology presents the first step of our inquiry into the patterns, causes and consequences of party switching in eight democracies (Estonia, Ireland, Italy, Lithuania, Norway, the Netherlands, Poland and Romania) from 1960s/1990s to early 2020s

    Does switching pay off? The impact of parliamentary party instability on individual electoral performance

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    Members of parliament who change their parliamentary party group (PPG) affiliation can be motivated by a variety of factors but the desire to improve their electoral prospects is often argued to be the among the most important. But does switching PPG affiliation improve or damage the electoral performance of those involved? We study the changes in electoral performance of Polish MPs involved in parliamentary party instability since the mid-1990s using an original dataset on all instances of switching compiled by the INSTAPARTY (Party Instability in Parliaments, https://instapartyproject.com) project. In addition to analyzing whether the MPs run for the parliament again in the following election, we zoom in on their electoral performance in terms of personal preference votes. We consider the electoral dividends of different types of switching and find that the effect of switching on personal electoral performance depends on the type of switching MPs were involved in
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