Improving Authenticated Dynamic Dictionaries, with Applications to Cryptocurrencies

We improve the design and implementation of two-party and three-party authenticated dynamic dictionaries and apply these dictionaries to cryptocurrency ledgers. A public ledger (blockchain) in a cryptocurrency needs to be easily verifiable. However, maintaining a data structure of all account balances, in order to verify whether a transaction is valid, can be quite burdensome: a verifier who does not have the large amount of RAM required for the data structure will perform slowly because of the need to continually access secondary storage. We demonstrate experimentally that authenticated dynamic dictionaries can considerably reduce verifier load. On the other hand, per-transaction proofs generated by authenticated dictionaries increase the size of the blockchain, which motivates us to find a solution with most compact proofs. Our improvements to the design of authenticated dictionaries reduce proof size and speed up verification by 1.4-2.5 times, making them better suited for the cryptocurrency application. We further show that proofs for multiple transactions in a single block can compressed together, reducing their total length by approximately an additional factor of 2. We simulate blockchain verification, and show that our verifier can be about 20 times faster than a disk-bound verifier under a realistic transaction load

Policies for biosimilar uptake in Europe : an overview

Background: Across European countries, differences exist in biosimilar policies, leading to variations in uptake of biosimilars and divergences in savings all over Europe. Objectives: The aim of this article is to provide an overview of different initiatives and policies that may influence the uptake of biosimilars in different European countries. Recommendations will be formulated on how to create sustainable uptake. Methods: An overview of policies on biosimilars was obtained via a questionnaire, supplemented with relevant articles. Topics were organized in five themes: availability, pricing, reimbursement, demand-side policies, and recommendations to enhance uptake. Results: In all countries studied, biological medicines are available. Restrictions are mainly dependent on local organization of the healthcare system. Countries are willing to include biosimilars for reimbursement, but for commercial reasons they are not always marketed. In two thirds of countries, originator and biosimilar products may be subjected to internal reference pricing systems. Few countries have implemented specific incentives targeting physicians. Several countries are implementing pharmacist substitution; however, the scope and rules governing such substitution tend to vary between these countries. Reported educational policies tend to target primarily physicians, whereas fewer initiatives were reported for patients. Recommendations as proposed by the different country experts ranged from the need for information and communication on biosimilars to competitive pricing, more support for switching and guidance on substitution. Conclusions: Most countries have put in place specific supply-side policies for promoting access to biosimilars. To supplement these measures, we propose that investments should be made to clearly communicate on biosimilars and educate stakeholders. Especially physicians need to be informed on the entry and use of biosimilars in order to create trust. When physicians are well-informed on the treatment options, further incentives should be offered to prescribe biosimilars. Gainsharing can be used as an incentive to prescribe, dispense or use biosimilars. This approach, in combination with binding quota, may support a sustainable biosimilar market

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom

The Implementation of Managed Entry Agreements in Central and Eastern Europe : Findings and Implications

Funding Information: In Bosnia and Herzegovina, both The Federation of Bosnia and Herzegovina and the Republic of Srpska, also have special funds and budgets in place for the financing of expensive medicines, which are innovative and under patent. Similar earmarked funds are available in Scotland (the New Medicines Fund funded by the Pharmaceutical Price Regulation Scheme [PPRS] rebates) [35] and England (the Cancer Drugs Fund) [36]. However, support for such earmarked funds is mixed. While they facilitate access, critics raised issues about fairness towards other disease areas and patient groups that are not eligible for special funding [3, 39]. Further, the views of a Patient and Clinician Engagement meeting in Scotland [37] and the end-of-life criteria in England [38] offer opportunities for special considerations affecting medicines for end-of-life and very rare conditions to be taken into account in the health technology assessment process. Funding Information: The authors would like to acknowledge Dr. Jan Jones from the Scottish Medicines Consortium, Scotland, for contributing to the discussion with information on Scotland, Drs. Lyudmila Bezmelnitsyna and Anastasia Isaeva for contributing to data collection in Russia and Dr. Kate?ina Podrazilov? from SZP ?R for providing information on the Czech Republic. Alessandra Ferrario was a Research Officer at the LSE Health at the time this research was conducted. She is now a postdoctoral Research Fellow at the Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, USA. Email: [email protected] No sources of funding were used for this study. The authors declare they have no conflicts of interest. However, Di?na Ar?ja, Maria Dimitrova, Jurij F?rst, Ieva Grei?i?t?-Kuprijanov, Iris Hoxha, Arianit Jakupi, Erki Laidm?e, Vanda Markovic-Pekovic, Dmitry Meshkov, Guenka Petrova, Maciej Pomorski and Patricia Vella Bonanno work directly for national health authorities or are advisers to them. Alessandra Ferrario, Tomasz Bochenek, Ileana Mardare, Dominik Tomek, Luka Voncina, Alan Haycox, Panos Kanavos,?Olga L?blov?, and Brian Godman are academics and independent researchers also working with national and regional health authorities and others to improve the quality and efficiency of prescribing, and Tarik Catic, D?vid Dank?,and Tanja Novakovic are involved with pharmaceutical, pharmacoeconomics and outcomes research groups in their countries. Olga L?blov? has also carried out remunerated consultancy activities for A&R Partners, Baxter AG and Instytut Arcana and Ileana Mardare has signed a consulting contract with Ewopharma A.G. Romania. The content of the paper and the conclusions are those of each author and may not necessarily reflect those of any organisation that employs them. Publisher Copyright: © 2017, The Author(s).Background: Managed entry agreements (MEAs) are a set of instruments to facilitate access to new medicines. This study surveyed the implementation of MEAs in Central and Eastern Europe (CEE) where limited comparative information is currently available. Method: We conducted a survey on the implementation of MEAs in CEE between January and March 2017. Results: Sixteen countries participated in this study. Across five countries with available data on the number of different MEA instruments implemented, the most common MEAs implemented were confidential discounts (n = 495, 73%), followed by paybacks (n = 92, 14%), price-volume agreements (n = 37, 5%), free doses (n = 25, 4%), bundle and other agreements (n = 19, 3%), and payment by result (n = 10, >1%). Across seven countries with data on MEAs by therapeutic group, the highest number of brand names associated with one or more MEA instruments belonged to the Anatomical Therapeutic Chemical (ATC)-L group, antineoplastic and immunomodulating agents (n = 201, 31%). The second most frequent therapeutic group for MEA implementation was ATC-A, alimentary tract and metabolism (n = 87, 13%), followed by medicines for neurological conditions (n = 83, 13%). Conclusions: Experience in implementing MEAs varied substantially across the region and there is considerable scope for greater transparency, sharing experiences and mutual learning. European citizens, authorities and industry should ask themselves whether, within publicly funded health systems, confidential discounts can still be tolerated, particularly when it is not clear which country and party they are really benefiting. Furthermore, if MEAs are to improve access, countries should establish clear objectives for their implementation and a monitoring framework to measure their performance, as well as the burden of implementation.publishersversionPeer reviewe

First searches for optical counterparts to gravitational-wave candidate events

During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

Barriers for Access to New Medicines: Searching for the Balance Between Rising Costs and Limited Budgets

Introduction: There is continued unmet medical need for new medicines across countries especially for cancer, immunological diseases and orphan diseases. However, there are growing challenges with funding new medicines at ever increasing prices along with funding increased medicine volumes with the growing prevalence of both infectious diseases and non-communicable diseases across countries. This has resulted in the development of new models to better manage the entry of new medicines, new financial models being postulated as well as strategies to improve prescribing efficiency. However, more needs to be done. Consequently, the primary aim of this paper is to consider potential ways to optimise the use of new medicines balancing rising costs with increasing budgetary pressures to stimulate debate especially from a payer perspective. Methods: A narrative review of pharmaceutical policies and implications, as well as possible developments, based on key publications and initiatives known to the co-authors principally from a health authority perspective. Results: A number of initiatives and approaches have been identified including new models to better manage the entry of new medicines based on three pillars (pre-, peri-, and post-launch activities). Within this, we see the growing role of horizon scanning activities starting up to 36 months before launch, managed entry agreements and post launch follow-up. It is also likely there will be greater scrutiny over the effectiveness and value of new cancer medicines given ever increasing prices. This could include establishing minimum effectiveness targets for premium pricing along with re-evaluating prices as more medicines for cancer lose their patent. There will also be a greater involvement of patients especially with orphan diseases. New initiatives could include a greater role of multicriteria decision analysis, as well as looking at the potential for de-linking research and development from commercial activities to enhance affordability. Conclusion: There are a number of ongoing activities across countries to try and fund new valued medicines whilst attaining or maintaining universal healthcare. Such activities will grow with increasing resource pressures and continued unmet need

Search for long-lived gravitational-wave transients coincident with long gamma-ray bursts

Long gamma-ray bursts (GRBs) have been linked to extreme core-collapse supernovae from massive stars. Gravitational waves (GW) offer a probe of the physics behind long GRBs. We investigate models of long-lived (~10–1000 s) GW emission associated with the accretion disk of a collapsed star or with its protoneutron star remnant. Using data from LIGO’s fifth science run, and GRB triggers from the Swift experiment, we perform a search for unmodeled long-lived GW transients. Finding no evidence of GW emission, we place 90% confidence-level upper limits on the GW fluence at Earth from long GRBs for three waveforms inspired by a model of GWs from accretion disk instabilities. These limits range from F<3:5 ergs cm⁻2 to F<1200 ergs cm⁻2, depending on the GRB and on the model, allowing us to probe optimistic scenarios of GW production out to distances as far as ≈ 33 Mpc. Advanced detectors are expected to achieve strain sensitivities 10× better than initial LIGO, potentially allowing us to probe the engines of the nearest long GRBs.J. Aasi ... D.J. Hosken ... W. Kim ... E.J. King ... J. Munch ... D. J. Ottaway ... P. J. Veitc

FIRST SEARCHES FOR OPTICAL COUNTERPARTS TO GRAVITATIONAL-WAVE CANDIDATE EVENTS

During the LIGO and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type

Searching for stochastic gravitational waves using data from the two colocated LIGO Hanford detectors

Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a colocated detector pair is more sensitive to a gravitational-wave background than a noncolocated detector pair. However, colocated detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of colocated detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO’s fifth science run. At low frequencies, 40–460 Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460–1000 Hz, these techniques are sufficient to set a 95% confidence level upper limit on the gravitational-wave energy density of Ω(f) < 7.7 × 10[superscript -4](f/900  Hz)[superscript 3], which improves on the previous upper limit by a factor of ~180. In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustDavid & Lucile Packard FoundationAlfred P. Sloan Foundatio