4,795 research outputs found

    System for generating timing and control signals

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    A system capable of generating every possible data frame subperiod and delayed subperiod of a data frame of length of M clock pulse intervals (CPIs) comprised of parallel modulo-m sub i counters is presented. Each m sub i is a prime power divisor of M and a cascade of alpha sub i identical modulo-p sub i counters. The modulo-p sub i counters are feedback shift registers which cycle through p sub i distinct states. Every possible nontrivial data frame subperiod and delayed subperiod is derived and a specific CPI in the data frame is detected. The number of clock pulses required to bring every modulo-p sub i counter to a respective designated state or count is determined by the Chinese remainder theorem. This corresponds to the solution of simultaneous congruences over relatively prime moduli

    Inventory of Greenhouse-Gas Mitigation Measures. Examples from the IIASA Technology Data Base

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    The comparative assessment of different strategies for reducing energy-related emissions of greenhouse gases is a major research area within the Environmentally Compatible Energy Strategies (ECS) Project at IIASA. An integral part of this work is the development of a mitigation technology inventory that encompasses a data base called CO2DB. The data base covers the full range of mitigation measures spanning efficiency improvements, conservation, enhanced use of low-carbon fuels, carbon-free sources of energy and other options such as afforestation and enhancement of carbon sinks. The data base includes detailed descriptions of the technical, economic and environmental performance of technologies as well as data pertinent to their commercialization, introduction and diffusion. Additional information includes literature sources, description of salient assumptions and how assessments were made. The primary purpose for the development of the CO2DB is to facilitate the analysis of technological options for reducing the global emissions of greenhouse gases, and in particular for assessing their potentials and costs. This working paper gives a description of selected technologies from the CO2DB. It also describes some of the most important assumptions behind the technology assessments and gives relevant literature sources. The examples chosen cover the energy system from primary energy production and conversion to energy end-use that results in actual energy services. The paper concludes by giving an example of an energy chain, also called full fuel-cycle analysis, with the associated costs and emissions. This example illustrates possible uses of the CO2DB as a tool for the assessment of mitigation potentials and costs. The data base can facilitate the assessment of carbon dioxide reduction, removal and storage technologies by combining many interrelated technologies together into the energy systems, i.e. to analyze measures throughout the energy chain from primary energy extraction to measures to improve energy. This paper can be used as a technical guide to the technology inventory in conjunction with the manual for the CO2DB software support system (WP-91-31a)

    TGF-β1 as a prognostic factor in the process of early osteoarthrosis in the rabbit knee

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    AbstractObjective To assess changes in knee joint fluid concentrations of transforming growth factor-β1 (TGF-β1) and proteoglycan (PG) fragments during the early course of post-traumatic osteoarthrosis (OA) after meniscectomy in the rabbit knee, and to ascertain whether the concentrations of these substances shortly after operation could be used as prognostic markers for the OA process.Design In 15 rabbits with medial meniscectomy in one knee and a sham operation in the other knee, synovial lavage fluid samples were taken repeatedly, before operation, every third week post-operatively until 12 weeks, thereafter every sixth week, and at death. Five rabbits each were killed at 13, 25 and 40 weeks. Synovial lavage fluid samples from five non-operated rabbits served as controls. At death, two histological scores were formed that characterized the highest (MAX) and the overall (ALL) degree of OA changes in each joint.Results TGF-β1 and PG fragment concentrations in synovial lavage fluid correlated highly (R=0.81, P< 0.001). Both OA scores were higher in meniscectomized than controls (P< 0.05). The synovial lavage fluid concentration of TGF-β1 at 3 weeks, but no other time point, correlated to the histological scores (ALL, R=0.58; MAX, R=0.52;P< 0.001).Conclusion Higher concentrations of TGF-β1 in synovial lavage fluid early after surgery seemed indicative for the later development of more severe OA changes in contrast to lower concentrations. The association between TGF-β1 and the changes found later in the cartilage was underlined by the high correlations between this substance and PG fragment concentrations in synovial lavage fluid at all time points

    Managing at the Speed of Light: Improving Mission-Support Performance

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    The House and Senate Energy and Water Development Appropriations Subcommittees requested this study to help DOE's three major mission-support organizations improve their operations to better meet the current and future needs of the department. The passage of the Recovery Act only increased the importance of having DOE's mission-support offices working in the most effective, efficient, and timely manner as possible. While following rules and regulations is essential, the foremost task of the mission-support offices is to support the department's mission, i.e., the programs that DOE is implementing, whether in Washington D.C. or in the field. As a result, the Panel offered specific recommendations to strengthen the mission-focus and improve the management of each of the following support functions based on five "management mandates":- Strategic Vision- Leadership- Mission and Customer Service Orientation- Tactical Implementation- Agility/AdaptabilityKey FindingsThe Panel made several recommendations in each of the functional areas examined and some overarching recommendations for the corporate management of the mission-support offices that they believed would result in significant improvements to DOE's mission-support operations. The Panel believed that adopting these recommendations will not only make DOE a better functioning organization, but that most of them are essential if DOE is to put its very large allocation of Recovery Act funding to its intended uses as quickly as possible

    Simultaneous changes in bone mineral density and articular cartilage in a rabbit meniscectomy model of knee osteoarthrosis

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    AbstractObjective It was hypothesized that increased bone mineral density of the medial proximal tibia would precede or coincide with the development of more severe cartilage changes after meniscectomy.Methods In a rabbit knee model, mineral density of subchondral bone and changes of articular cartilage were monitored 13 to 40 weeks after medial meniscectomy or a sham operation.Results Both procedures resulted in a decrease of bone mineral density, especially of the medial proximal tibia, which persisted up to 40 weeks (P< 0.02–0.0007). Meniscectomy induced cartilage changes typical for osteoarthrosis (P< 0.009), which progressed over time on the posterior aspect of the medial tibial plateau (P< 0.009), which is physiologically covered by the meniscus, but the procedure also induced iatrogenic changes which were located mainly on the anterior aspect of the concerned compartment, and which did not progress or develop to osteoarthrosis.Conclusions The data suggest that the cartilage changes after meniscectomy in this animal model are caused by the surgical trauma, subsequent limb misuse, and altered load distribution, and initially associated by a decrease not an increase in bone mineral density of the proximal tibia. Moreover, the cartilage changes progressed without a simultaneous increase of the bone mineral density at corresponding sites

    Researching trust in the police and trust in justice: a UK perspective

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    This paper describes the immediate and more distant origins of a programme of comparative research that is examining cross-national variations in public trust in justice and in the police. The programme is built around a module of the fifth European Social Survey, and evolved from a study funded by the European Commission. The paper describes the conceptual framework within which we are operating – developed in large measure from theories of procedural justice. It reviews some of the methodological issues raised by the use of sample surveys to research issues of public trust in the police, public perceptions of institutional legitimacy and compliance with the law. Finally it gives a flavour of some of the early findings emerging from the programme

    Identifying a spatial scale for the analysis of residential burglary: An empirical framework based on point pattern analysis

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    A key issue in the spatial and temporal analysis of residential burglary is the choice of scale: spatial patterns might differ appreciably for different time periods and vary across geographic units of analysis. Based on point pattern analysis of burglary incidents in Columbus, Ohio during a 9-year period, this study develops an empirical framework to identify a useful spatial scale and its dependence on temporal aggregation. Our analysis reveals that residential burglary in Columbus clusters at a characteristic scale of 2.2 km. An ANOVA test shows no significant impact of temporal aggregation on spatial scale of clustering. This study demonstrates the value of point pattern analysis in identifying a scale for the analysis of crime patterns. Furthermore, the characteristic scale of clustering determined using our method has great potential applications: (1) it can reflect the spatial environment of criminogenic processes and thus be used to define the spatial boundary for place-based policing; (2) it can serve as a candidate for the bandwidth (search radius) for hot spot policing; (3) its independence of temporal aggregation implies that police officials need not be concerned about the shifting sizes of risk-areas depending on the time of the year

    Nonlinear elasticity of stiff biopolymers connected by flexible linkers

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    Networks of the biopolymer actin, cross-linked by the compliant protein filamin, form soft gels. They can, however, withstand large shear stresses due to their pronounced nonlinear elastic behavior. The nonlinear elasticity can be controlled by varying the number of cross-links per actin filament. We propose and test a model of rigid filaments decorated by multiple flexible linkers that is in quantitative agreement with experiment. This allows us to estimate loads on individual cross-links, which we find to be less than 10 pN. © 2009 The American Physical Society

    Long-Term Survival after Blood and Marrow Transplantation: Comparison with an Age- and Gender-Matched Normative Population

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    AbstractA plateau in long-term survival patterns of patients undergoing blood and marrow transplantation (BMT) from allogeneic donors is apparent, but whether their expected survival ever parallels that of the normative population is unclear. This study attempts to identify a cutoff time for classifying BMT patients as long-term survivors and compares their actual survival with the expected survival of an age- and gender-matched “normal” population. In this study, the records of 1386 patients who underwent allogeneic BMT at Princess Margaret Hospital between 1970 and 2002 were reviewed. Hazard rates (HRs), Kaplan-Meier survival estimates, and loess curves were used to propose a cutoff time classifying patients as long-term survivors. Factors predictive of overall survival and survival for long-term survivors were investigated. Actual survival for these patients was compared with the expected survival of the Canadian “normal” population. A cutoff time of 6 years post-BMT was proposed to define long-term survivors based on loess curves of hazard ratios and yearly survival statistics. The only statistically significant predictor of survival among long-term survivors was having a male donor (HR = 0.39; 95% confidence interval [CI] = 0.17–0.88). Although only 62% of patients survived the first year post-BMT, 98.5% of patients alive after 6 years survived at least another year. Almost 1/3 (31%) of the deaths in long-term survivors resulted from causes unrelated to transplantation or relapse. The observed number of deaths among BMT patients exceeded the expected number from the Canadian population; however, the difference in life expectancy decreased the longer that a patient survived. The 95% CIs for the observed/expected number of deaths cover 1, indicative of no difference, after the tenth year post-BMT. A cutoff of 6 years is proposed to define long-term survivorship after BMT. Life expectancy remained reduced compared with that of the “normal” population; however, this difference decreased the longer that a patient survived. Known risk factors of short-term survival disappeared, with only donor gender predictive of survival among long-term survivors
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