Response-Time Analysis for Non-Preemptive Global Scheduling with {FIFO} Spin Locks

Motivated by the lack of response-time analyses for non-preemptive global scheduling that consider shared resources, this paper provides such an analysis for global job-level fixed-priority (JLFP) scheduling policies and FIFO-ordered spin locks. The proposed analysis computes response-time bounds for a set of resource-sharing jobs subject to release jitter and execution-time uncertainties by implicitly exploring all possible execution scenarios using state-abstraction and state-pruning techniques. A large-scale empirical evaluation of the proposed analysis shows it to be substantially less pessimistic than simple execution-time inflation methods, thanks to the explicit modeling of contention for shared resources and scenario-aware blocking analysis

Willingness to undergo surgery again validated clinically important differences in health-related quality of life after total hip replacement or total knee replacement surgery

AbstractObjectivesTo determine clinically important differences (CIDs) in health-related quality of life (HRQoL) after total hip replacement (THR) or total knee replacement (TKR) surgery, using the Short Form 36 (SF-36).Study Design and SettingSF-36 scores were collected 2 weeks before and at 1.5–6 years after joint replacement in 586 THR and 400 TKR patients in a multicenter cohort study. We calculated distribution-based CIDs (0.8 standard deviations of the preoperative score) for each SF-36 subscale. Responders (patients with an improvement in HRQoL ≥ CID of a particular subscale) were compared with nonresponders using an external validation question: willingness to undergo surgery again.ResultsCIDs for THR/TKR were physical functioning (PF), 17.9/16.7; role-physical (RP), 31.1/33.4; bodily pain (BP), 16.8/16.2; general health, 15.5/15.7; vitality, 17.3/16.7; social functioning (SF), 22.0/19.9; role-emotional, 33.7/33.6; and mental health, 14.8/14.1. CIDs of PF, RP, BP, and SF were validated by the validation question.ConclusionValid and precise CIDs are estimated of PF, RP, BP, and SF, which are relevant in HRQoL subscales for THR and TKR patients. CIDs of all other subscales should be used cautiously

Hysteresis and re-entrant melting of a self-organized system of classical particles confined in a parabolic trap

A self-organized system composed of classical particles confined in a two-dimensional parabolic trap and interacting through a potential with a short-range attractive part and long-range repulsive part is studied as function of temperature. The influence of the competition between the short-range attractive part of the inter-particle potential and its long-range repulsive part on the melting temperature is studied. Different behaviors of the melting temperature are found depending on the screening length ($\kappa$) and the strength ($B$) of the attractive part of the inter-particle potential. A re-entrant behavior and a thermal induced phase transition is observed in a small region of ($\kappa,B$)-space. A structural hysteresis effect is observed as a function of temperature and physically understood as due to the presence of a potential barrier between different configurations of the system.Comment: 8 pages, 6 figure

All-polyethylene tibial components in TKA in rheumatoid arthritis: a 25-year follow-up study

PURPOSE: There is renewed interest in the all-polyethylene tibial component in total knee arthroplasty (TKA). Long-term results of this prosthesis in rheumatoid arthritis (RA) patients, however, are limited. Therefore, we studied 104 primary cemented all-polyethylene tibial TKA in 80 consecutive RA patients for up to 25 years to determine the long-term survival of all-polyethylene tibial components in patients suffering from end stage RA. METHODS: We estimated revision rates according the revision rate per 100 observed component years used in national joint registries. Kaplan-Meier was used to estimate survival curves. RESULTS: During the 25-year follow-up, three revisions for tibial component loosening were performed. The mean revision rate of all-polyethylene tibial components with revision for aseptic loosening as the endpoint was 0.09 per 100 observed component years. This corresponds to a revision rate of 0.9% after ten years and 2.25% after 25 years. Survivorship according to Kaplan-Meier was 100% at ten years and 87.5% at 25 years [95% confidence interval (CI) 64.6-100)]. CONCLUSION: This study shows good long-term results of all-polyethylene tibial TKA in patients with RA. RA patients with multiple-joint inflammation may be less physically active than osteoarthritis patients, resulting in a lower demand on the prosthesis, and these patients may, indeed, be good candidates for all-polyethylene tibial TKA. Our results suggest that all-polyethylene tibial TKA could be a successful and cost-saving treatment for end-stage knee arthritis in RA patients.Optimising joint reconstruction management in arthritis and bone tumour patient

Transition from single-file to two-dimensional diffusion of interacting particles in a quasi-one-dimensional channel

Diffusive properties of a monodisperse system of interacting particles confined to a \textit{quasi}-one-dimensional (Q1D) channel are studied using molecular dynamics (MD) simulations. We calculate numerically the mean-squared displacement (MSD) and investigate the influence of the width of the channel (or the strength of the confinement potential) on diffusion in finite-size channels of different shapes (i.e., straight and circular). The transition from single-file diffusion (SFD) to the two-dimensional diffusion regime is investigated. This transition (regarding the calculation of the scaling exponent ($\alpha$) of the MSD $$ $\propto t^{\alpha}$) as a function of the width of the channel, is shown to change depending on the channel's confinement profile. In particular the transition can be either smooth (i.e., for a parabolic confinement potential) or rather sharp/stepwise (i.e., for a hard-wall potential), as distinct from infinite channels where this transition is abrupt. This result can be explained by qualitatively different distributions of the particle density for the different confinement potentials.Comment: 13 pages, 11 figure

Beschermde gebieden Noordzee: noodzaak en mogelijkheden

This study on protected areas in the North Sea has been carried out for the Directorate of Nature, Environment and Fauna Management of the Ministry of Agriculture, Nature Management and Fisheries. It is part of a project (project number 22) of the Nature Policy Plan of this Ministry. The objective of the study, as defined by the Directorate of Nature, Environment and Fauna Management, is to review the necessity and feasibility of the designation of protected areas in the Dutch sector of the North Sea as a contribution to the conservation and, where possible, rehabilitation of a natural diversity of ecologically valuable areas with their specific communities and characteristic species. The objectives for the designation of marine protected areas are given in chapter 2 of the report: To preserve, rehabilitate and develop natural values in the Dutch sector of the North Sea by limiting the effects of those human activities that cause detectable changes in the North Sea ecosystem . To protect groups of animals which are an integral part of the natural values of the Dutch sector of the North Sea and whose existence or 'normal' functioning is currently threatened within this part of the North Sea. The study only addresses those human activities which can be controlled within the boundaries of the Dutch sector of the North Sea itself: fisheries, off-shore mining, sand and gravel extraction, military activities, shipping, pipelines and telecommunication cables. Pollution from land-based sources, atmospheric deposition, dumping and calamities have therefore not been considered in this report. Chapter 3 contains a description of the North Sea ecosystem (plankton, benthos, fish, seabirds and marine mammals). An effort was made to develop an ecological zoning for each of these groups of animals (see map on back cover). In many cases it has been possible to present relevant (a)biotic parameters. These parameters have played an important role in the final choice of protected areas. The distribution of plankton is to a large extent related to the position of water-bodies in the Dutch sector of the North Sea. The following areas can be identified: coastal water, southern North Sea, central North Sea and the Frisian Front area. The distribution of micro-, meio- and macrobenthos is largely determined by sediment types (sand, mud, gravel, stones). By and large, the following clusters can be identified with respect to infauna (macrobenthos living in the sediments) and epifauna (macrobenthos living on the seafloor): the Southern Bight including the coastal zone, Oystergrounds, Dogger Bank, the area north of the Dogger Bank, the Frisian Front area and the Klaverbank. The distribution of fish is not only determined by such factors as temperature, food, sediment type and water depth, but also by the presence of spawning and nursery areas and the location of migratory routes. With respect to seabirds, four different areas can be identified: the coastal zone, the Southern Bight, the Frisian Front area and the northern part of the Dutch sector of the North Sea. The distribution of seabirds is determined by such factors as the presence of breeding areas, migratory and wintering movements, feeding methods and availability of food. The distribution of marine mammals depends on the species. Porpoises are found both in the northern part of the Dutch sector of the North Sea and in the coastal zone north of the Frisian Islands. Dolphins are rarely seen in coastal waters. The effects of human activities in the Dutch sector of the North Sea are discussed in chapter 4 and can be summarized as follows. Fishery is a frequent large-scale activity which throughout the Dutch sector of the North Sea has resulted in considerable changes within the ecosystem. There is hardly any place where benthic communities can develop undisturbed. At least 10 benthic species have disappeared or their numbers have decreased substantially. The spawning stocks and stability of many fish stocks have decreased substantially as well. Some bird species, however, have increased in numbers. In addition, intensive fisheries have possibly contributed to the decline of sea mammal populations. Offshore mining can, as a result of discharges of cuttings contaminated with oil-based muds (OBM), result in long-term local effects on the benthic system. Effects of water-based muds (WBM) cannot be ruled out, but will be found in smaller areas over a shorter period of time than the effects of OBM. Effects of discharges of production water have not been observed but could occur locally with effects on plankton, fish and birds. It seems unlikely that acoustic disturbance by offshore mining (including seismic surveys) should affect sea mammals which are more that 100 m away from the installation producing the disturbance. Some disturbance may occur as a result of ship and helicopter movements associated with offshore mining. Sand and gravel extraction and the laying of pipelines and telecommunication cables will result in local effects on the benthic system. The destruction of shellfish beds in the coastal zone by sand or gravel extraction might have long-term effects on scoters. It is not possible to quantify the effects of substances introduced into the marine environment by shipping and military activities. Noise produced by such activities may affect communication between sea mammals and behaviour of seabirds. There may be a recovery of those populations which are affected by fisheries. discharges from mining installations, sand and gravel extraction and the laying of pipelines and telecommunication cables after termination of these activities in certain parts of the Dutch sector of the North Sea. This would contribute to the recovery and conservation of these populations in the North Sea in general (see chapter 5). In general, recovery of communities may take 1 to 20 years (benthos and fish), 5 to 50 years (for seabirds) and 20 to more then 50 years (for sea mammals). Recovery will be impossible if gravel extraction has resulted in the removal of the entire layer of gravel on the seafloor. Chapters 6 and 7 give the objectives and related criteria which are used for the designation and the selection of areas which qualify for a protected status. The first criterion addresses the extent to which specific activities have developed into a threat to the existence or normal functioning of groups of animals or species in the Dutch sector of the North Sea. Fishery activities result in large-scale effects on a large number of ecological groups (benthos, fish, seabirds, marine mammals) in the Dutch sector of the North Sea. Discharges of cuttings contaminated with OBM result in long-term local benthic effects. Other discharges by offshore mining installations and sand and gravel extraction have local but possibly large-scale effects on benthos in specific relatively small areas such as the Frisian Front area or the Klaverbank. The second criterion addresses the question whether a prohibition or restriction of certain human activities in specific areas would reduce the threat to those groups of animals or species which were identified through the application of the first criterion. Alternatives for prohibitive or restrictive measures are also discussed. The designation of protected areas where certain activities are prohibited or restricted has the potential to contribute to the conservation or recovery of threatened species. In a number of cases there is no alternative other than the designation of protected areas. This is true of the threat to the benthos and fish which is caused by fisheries activities in the (Dutch sector of the) North Sea, and, in specific relatively small areas, it is also true of the threat to benthos caused by discharges from offshore mining installations and by sand and gravel extraction. The third criterion is used for identifying the areas most suitable for a protected Status on the basis of the ecology of groups of animals or species which need protection. Ecological criteria such as diversity, representativeness. integrity and vulnerability have been used. The application of ecological criteria results in the general conclusion that, within the Dutch sector of the North Sea, the following types of areas qualify for a protected status: a sandy area, a muddy area, an area with frontal characteristics and a gravel area. A protected area should contain coastal waters and an adequate depth gradient. An unbroken area which contains areas of all types would be the most effective option for protection. For the protection of benthos species with a limited migration, areas of circa one hundred square kilometers each should be sufficient; for fish species with an extensive migration pattern it would be necessary to protect a large part of the whole North Sea. It is concluded that for the protection of those species which are most characteristic of the Dutch sector of the North Sea it is necessary to protect an area with a total surface of some 31 ICES blocks (each some 60 x 60 square kilometers). The fourth criterion addresses the question whether there are adequate legal instruments to ensure effective protection of the selected areas. On the basis of existing legal instruments it is, in principle, possible to protect these areas. However; there are certain problems associated with measures which are required with respect to fisheries, gravel extraction and offshore mining. On the basis of the above criteria it is concluded that two areas within the Dutch sector of the North Sea qualify for a protected status: 1. An area directly northwest of the Frisian Islands (see Figs A and B). In this unbroken area of some 10,000 square kilometers it will be possible to protect a combination of different types of benthic communities (coastal waters, sandy bottoms, the Frisian Front area, muddy areas and restricted areas with gravel and stones). The area will also have an adequate depth gradient. The proposed area contains important spawning and nursery areas for fish (including squid) and habitats of many (non-commercial) fish species. Seasonal migratory routes to and from the Wadden Sea are concentrated in this area. Relatively large numbers of porpoises as well as dolphins and seabirds occur in this area. Protection of this area also strengthens the functioning of the Wadden Sea as a nursery area and supports the recolonisation of benthos in the Wadden Sea after, for instance, severe winters. There are two alternative options for the exact location of the area to be protected. The first alternative (Fig. A) has been chosen especially with an emphasis on conservation and recovery of the diversity of communities in the Dutch sector of the North Sea. The second alternative (Fig. B) more closely relates to existing measures regarding fisheries. The proportion of muddy areas is very low in this alternative. An expansion of the proposed area in an easterly direction could be considered only if it connected the area with similar protected areas in the German sector of the North Sea. An expansion of the proposed area in a southerly direction would more closely relate to the ecological interests of the Wadden Sea. The following protective measures are proposed for this area: The area will be closed for all types of fisheries throughout the year; Discharges from offshore mining installations which contain oil will be prevented (OBM) or minimized (production water); Additional area-specific protective measures with respect to offshore mining, shipping, military activities, sand extraction, dumping and the laying of pipelines can be considered whenever the situation in this area calls for such measures. Such measures should also be considered for areas to be used as reference areas for scientific research; The application of policies resulting from the implementation of international conventions with respect to conservation (the EC Bird Directive, the Conventions of Bonn, Berne and Ramsar, the proposed EC Habitat Directive). 2. Klaverbank (see Figs A and B). The Klaverbank, the only gravel area of importance in the Dutch sector of the North Sea, has a still relatively undisturbed benthic fauna which is specific to this type of area. The Klaverbank (approximately 800 square kilometers) should be given a protected status under which gravel extraction is prohibited. and discharges from offshore mining installations which contain oil will be prevented (OBM) or minimized (production water). Fisheries too should be prohibited but the limited size of this area rules out effective implementation and enforcement of such a measure. It is therefore advisable to develop proposals in cooperation with the United Kingdom for the designation of a protected area in the UK sector of the North Sea which should contain a large gravel area and possibly also the Klaverbank. If a decision is taken to protect these areas, it will be necessary to develop a management plan. Chapter 8 gives a possible outline for such a management plan, including certain relevant issues. Firstly, it will be necessary to define objectives for these specific areas in addition to the objectives already defined for the designation of protected areas in general. Secondly, it will be necessary to attune measures for the management of these areas to the objectives of their protection. A management plan will also have to address the organizational structure required for effective management of these areas. Arrangements for adequate enforcement and effective control of measures taken are also necessary. Programmes for scientific research will have to be developed

Improved clinical investigation and evaluation of high-risk medical devices: the rationale and objectives of CORE-MD (Coordinating Research and Evidence for Medical Devices).

In the European Union (EU), the delivery of health services is a national responsibility but there are concerted actions between member states to protect public health. Approval of pharmaceutical products is the responsibility of the European Medicines Agency, while authorising the placing on the market of medical devices is decentralised to independent 'conformity assessment' organisations called notified bodies. The first legal basis for an EU system of evaluating medical devices and approving their market access was the Medical Device Directive, from the 1990s. Uncertainties about clinical evidence requirements, among other reasons, led to the EU Medical Device Regulation (2017/745) that has applied since May 2021. It provides general principles for clinical investigations but few methodological details - which challenges responsible authorities to set appropriate balances between regulation and innovation, pre- and post-market studies, and clinical trials and real-world evidence. Scientific experts should advise on methods and standards for assessing and approving new high-risk devices, and safety, efficacy, and transparency of evidence should be paramount. The European Commission recently awarded a Horizon 2020 grant to a consortium led by the European Society of Cardiology and the European Federation of National Associations of Orthopaedics and Traumatology, that will review methodologies of clinical investigations, advise on study designs, and develop recommendations for aggregating clinical data from registries and other real-world sources. The CORE-MD project (Coordinating Research and Evidence for Medical Devices) will run until March 2024. Here, we describe how it may contribute to the development of regulatory science in Europe. Cite this article: EFORT Open Rev 2021;6:839-849. DOI: 10.1302/2058-5241.6.210081

The Exeter femoral stem continues to migrate during its first decade after implantation: 10–12 years of follow-up with radiostereometric analysis (RSA)

Optimising joint reconstruction management in arthritis and bone tumour patient

Complications and outcome of cats with congenital extrahepatic portosystemic shunts treated with thin film: Thirty-four cases (2008-2017)

Background: Congenital extrahepatic portosystemic shunts (CEHPSS) are rare in cats. Outcome after attenuation of CEHPSS with thin film has been described in a small number of cases. Objectives: To describe the clinical presentation, postoperative complications, and outcome of cats treated with thin film to attenuate CEHPSS. Animals: Thirty‐four cats with CEHPSS were identified from the database of 3 institutions over 9 years. Methods: Retrospective study. Medical records were reviewed to identify cats with a diagnosis of a CEHPSS that underwent surgical attenuation. Congenital extrahepatic portosystemic shunts were suspected from clinical signs, clinicopathologic findings, and diagnostic imaging, and confirmed at exploratory laparotomy. Cats treated with thin film band attenuation were included. Postoperative complications and follow‐up were recorded. Results: Complications were recorded in 11 of 34 cats. Deaths related to CEHPSS occurred in 6 of 34; 4 cats did not survive to discharge. Persistent seizures were the cause of death in 4 cats. Seizures were recorded in 8 of 34 cats after surgery; all these cats received preoperative antiepileptic drugs. Serum bile acid concentrations normalized in 25 of 28 of the cats for which data was available. Three cats had persistently increased serum bile acid concentrations and underwent a second exploratory laparotomy. One had a patent shunt, the other 2 had multiple acquired portosystemic shunts. Median follow‐up was 8 months (0.5‐84 months). Conclusions and Clinical Importance: Congenital extrahepatic portosystemic shunts attenuation using thin film in cats carries a good short‐ and mid‐term prognosis if they survive the postoperative period. Seizures were the most common cause of death