783,995 research outputs found

    Determining Punching Shear Strength and Performance of Tubular Joints Models

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    This report presents the integrated progress of the study on the effect of types of tubular connections onto the punching shear capacity. In various cases, punching shear failure is the common steel jacket structure failure factor. This project studies the association of the connection types as the main parameter to the punching shears capacity of the joints. The scope of the project is extended to study the effects of brace-chord angles onto the joint performance and the economic perspective of joints fabrications, SACS modeling and simulations were implemented to obtain the parametric analysis of the joints behavior and the ultimate strength of the joints. Through this study, types of joints that are superior to punching shear stress have been identified. The study has also established the critical brace-chord angle regions and the relationship between the chord stresses and the punching shear strength. The economic benefits of joint optimization are explicated through the fabrication cost analysis. Further extensive study is recommended to indicate other parameters influencing the strength behavior of the joint models

    A multivariate methodology for modelling regional development in Croatia

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    This paper proposes a multivariate statistical approach based on covariance structure analysis for assessment of the regional development level with an application to development ranking of 545 Croatian municipalities. Municipality-level data ware collected on economic, structural, and demographic dimensions and preliminary factor and principal component analysis were computed to analyse empirical groupings of the variables. Next, confirmatory factor analytic models were estimated with the maximum likelihood technique and subsequently their implied structure was formally tested. Testing was extended to a joint model including all three dimensions (economic, structural and demographic) and their covariance structure was modelled with a recursive structural equation model. Finally, scores were estimated for latent variables thereby allowing (i) estimation of the latent development level of the territorial units, (ii) ranking of all units on an interval scale in respect to their latent development level, and (iii) selection of a given percentage of units for inclusion into special state-care subsidy programme

    Beyond BAO: improving cosmological constraints from BOSS with measurement of the void-galaxy cross-correlation

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    We present a measurement of the anisotropic void-galaxy cross-correlation function in the CMASS galaxy sample of the BOSS DR12 data release. We perform a joint fit to the data for redshift space distortions (RSD) due to galaxy peculiar velocities and anisotropies due to the Alcock-Paczynski (AP) effect, for the first time using a velocity field reconstruction technique to remove the complicating effects of RSD in the void centre positions themselves. Fits to the void-galaxy function give a 1% measurement of the AP parameter combination DA(z)H(z)/c=0.4367±0.0045D_A(z)H(z)/c = 0.4367\pm 0.0045 at redshift z=0.57z=0.57, where DAD_A is the angular diameter distance and HH the Hubble parameter, exceeding the precision obtainable from baryon acoustic oscillations (BAO) by a factor of ~3.5 and free of systematic errors. From voids alone we also obtain a 10% measure of the growth rate, fσ8(z=0.57)=0.501±0.051f\sigma_8(z=0.57)=0.501\pm0.051. The parameter degeneracies are orthogonal to those obtained from galaxy clustering. Combining void information with that from BAO and galaxy RSD in the same CMASS sample, we measure DA(0.57)/rs=9.383±0.077D_A(0.57)/r_s=9.383\pm 0.077 (at 0.8% precision), H(0.57)rs=(14.05±0.14)  103H(0.57)r_s=(14.05\pm 0.14)\;10^3 kms1^{-1}Mpc1^{-1} (1%) and fσ8=0.453±0.022f\sigma_8=0.453\pm0.022 (4.9%), consistent with cosmic microwave background (CMB) measurements from Planck. These represent a factor \sim2 improvement in precision over previous results through the inclusion of void information. Fitting a flat cosmological constant Λ\LambdaCDM model to these results in combination with Planck CMB data, we find up to an 11% reduction in uncertainties on H0H_0 and Ωm\Omega_m compared to use of the corresponding BOSS consensus values. Constraints on extended models with non-flat geometry and a dark energy of state that differs from w=1w=-1 show an even greater improvement.Comment: 22 pages, 15 figures. Accepted for publication in Phys.Rev.D. v2 corrects small error in likelihood analysis; minor changes to figures and text, cosmological results unchanged. Reconstruction and void-finding code available at https://github.com/seshnadathur/Revolver, likelihood analysis code available at https://github.com/seshnadathur/void-galaxy-cosmo-fitte

    Dynamic phosphorus and nitrogen yield response model for economic optimisation

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    This paper provides an approach for modelling joint impact of two main nutrients in crop production for situations where there are available separate datasets for nitrogen and phosphorus fertiliser field experiments. Developing yield response models for Finnish spring barley crops (Hordeum vulgare L.) for clay and coarse soils and applying the models for dynamic economic analysis demonstrate the modelling approach. Model selection is based on iterative elimination from a wide diversity of plausible model formulations. Nonlinear weighted least squares method was utilised in estimation of the yield response models and dynamic programming was utilised in economic analysis. Our results suggest that fertiliser recommendations can be insufficient if soil phosphorus dynamics are ignored. Further, the optimal fertilisation rates for nitrogen and phosphorus, as well as the economic alternative costs of agri-environmental programmes depend on the soil texture of production area. Therefore, the efficiency of such programmes could be improved by targeting different fertilisation limits for different soil textures. In addition, uncertainty analysis revealed that the parameter uncertainty had a greater effect on the model output than the structural uncertainty. Further, the interaction of nitrogen and phosphorus fertilisers appeared to be a factor of relatively minor importance. The modelling approach and the model structure can be extended to other geographical areas, given that adequate datasets are available.This paper provides an approach for modelling joint impact of two main nutrients in crop production for situations where there are available separate datasets for nitrogen and phosphorus fertiliser field experiments. Developing yield response models for Finnish spring barley crops (Hordeum vulgare L.) for clay and coarse soils and applying the models for dynamic economic analysis demonstrate the modelling approach. Model selection is based on iterative elimination from a wide diversity of plausible model formulations. Nonlinear weighted least squares method was utilised in estimation of the yield response models and dynamic programming was utilised in economic analysis. Our results suggest that fertiliser recommendations can be insufficient if soil phosphorus dynamics are ignored. Further, the optimal fertilisation rates for nitrogen and phosphorus, as well as the economic alternative costs of agri-environmental programmes depend on the soil texture of production area. Therefore, the efficiency of such programmes could be improved by targeting different fertilisation limits for different soil textures. In addition, uncertainty analysis revealed that the parameter uncertainty had a greater effect on the model output than the structural uncertainty. Further, the interaction of nitrogen and phosphorus fertilisers appeared to be a factor of relatively minor importance. The modelling approach and the model structure can be extended to other geographical areas, given that adequate datasets are available

    Diffusion on a lattice: transition rates, interactions and memory effects

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    We analyze diffusion of particles on a two dimensional square lattice. Each lattice site contains an arbitrary number of particles. Interactions affect particles only in the same site, and are macroscopically represented by the excess chemical potential. In a recent work, a general expression for transition rates between neighboring cells as functions of the excess chemical potential was derived. With transition rates, the mean field tracer diffusivity, DMFD^\text{MF}, is immediately obtained. The tracer diffusivity, D=DMFfD = D^\text{MF} f, contains the correlation factor ff, representing memory effects. An analysis of the joint probability of having given numbers of particles at different sites when a force is applied to a tagged particle allows an approximate expression for ff to be derived. The expression is applied to soft core interaction (different values for the maximum number of particles in a site are considered) and extended hard core

    Bayesian emulation for optimization in multi-step portfolio decisions

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    We discuss the Bayesian emulation approach to computational solution of multi-step portfolio studies in financial time series. "Bayesian emulation for decisions" involves mapping the technical structure of a decision analysis problem to that of Bayesian inference in a purely synthetic "emulating" statistical model. This provides access to standard posterior analytic, simulation and optimization methods that yield indirect solutions of the decision problem. We develop this in time series portfolio analysis using classes of economically and psychologically relevant multi-step ahead portfolio utility functions. Studies with multivariate currency, commodity and stock index time series illustrate the approach and show some of the practical utility and benefits of the Bayesian emulation methodology.Comment: 24 pages, 7 figures, 2 table

    Robots that can adapt like animals

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    As robots leave the controlled environments of factories to autonomously function in more complex, natural environments, they will have to respond to the inevitable fact that they will become damaged. However, while animals can quickly adapt to a wide variety of injuries, current robots cannot "think outside the box" to find a compensatory behavior when damaged: they are limited to their pre-specified self-sensing abilities, can diagnose only anticipated failure modes, and require a pre-programmed contingency plan for every type of potential damage, an impracticality for complex robots. Here we introduce an intelligent trial and error algorithm that allows robots to adapt to damage in less than two minutes, without requiring self-diagnosis or pre-specified contingency plans. Before deployment, a robot exploits a novel algorithm to create a detailed map of the space of high-performing behaviors: This map represents the robot's intuitions about what behaviors it can perform and their value. If the robot is damaged, it uses these intuitions to guide a trial-and-error learning algorithm that conducts intelligent experiments to rapidly discover a compensatory behavior that works in spite of the damage. Experiments reveal successful adaptations for a legged robot injured in five different ways, including damaged, broken, and missing legs, and for a robotic arm with joints broken in 14 different ways. This new technique will enable more robust, effective, autonomous robots, and suggests principles that animals may use to adapt to injury

    Combined Point of Care Tools Are Able to Improve Treatment Adherence and Health-Related Quality of Life in Patients with Severe Hemophilia: An Observational Prospective Study

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    Introduction: Ultrasound (US) assessment of joints is an evolving point of care tool for the detection of early joint arthropathy (Napolitano M, Kessler CM. Hemophilia A and B. Consultative Hemostasis and Thrombosis, Kitchens, 4th edition); population pharmacokinetic (pop-PK) studies are adopted as a useful instrument to set the prophylaxis regimen for patients with hemophilia, they may improve adherence (Nagao A.et al. Thromb Res. 2019 Jan; 173:79-84) and reduce the annual bleeding rate (ABR). Adherence to continuous intravenous administrations of factor VIII or Factor IX products is challenging, thus patients may experience breakthrough bleedings while on prophylaxis. Repeated US examinations of joint status have recently been advocated to attempt to remedy sub-optimal medication adherence (Di Minno A et al., Blood Rev. 2019 Jan;33:106-116). Aim of the current prospective analysis was to evaluate the impact of combined US assessment and pop-PK study on adherence to treatment and health related quality of life in patients with severe hemophilia A(HA) and B (HB) under regular prophylaxis. Material and methods: This prospective observational study was performed at a single tertiary center from January 2017 to June 2019. Research was conducted following the Helsinki Declaration. All patients included in the study provided a written informed consent for study participation. Patients with severe HA and HB routinely underwent, as part of regular 12-months follow-up visits, the following: US joints evaluation of elbows, knees and ankles using the HEAD-US protocol, treatment adherence evaluation by VERITAS-Pro questionnaire, health –related quality of life assessment by the standardized EQ-5D,EQ-VAS and pop-PK study (WAPPS-Hemo, McMaster University) as needed (i.e.in case of changes in life style, planned treatment switch); each patient visualised US and his estimated PK profile during medial encounters. Compliance to the prescribed treatment was also determined by analysis of patient diaries with infusion logs. Statistical analysis was performed using the SPSS software version 25.0 (SPSS Chicago, IL). Statistical tests were 2-sided, with a significance threshold of 0.05. Results: Twenty consecutive males with severe haemophilia were included in the current analysis, 13 with severe HA, 2 with HA with previous inhibitors and 5 HB, with a median age of 30 (range 14- 56) years and a median ABR of 5 (range:0-12). Nine patients were under primary prophylaxis, 8 under secondary prophylaxis and 3 under tertiary prophylaxis, they all self-infused at home. Four patients had one target joint and 3 patients had multiple target joints. For each enrolled subject, HEAD-US score, VERITAS-pro, EQ5D and EQ-VAS score were assessed at enrolment (T0) and at 12 (T12) and 24 (T24) months follow-up visits, respectively. Pop-PK was assessed in 11 patients: in 7 (5 HA,2 HB) it was assessed twice, before and after treatment switch to extended half-life (EHL) products, in 4 it was assessed once to modify prophylaxis treatment schedules for a more active life-style (N=2) or weight changes (N=2). Median ABR was 4 at T12 and 3.8 at T24. Reported breakthrough bleeds at T12 were 14, mainly trauma-related (N= 8) or affecting target joints (N=4), they were not reported at T24 in patients with PK-driven modified schedules (N=4) and in 4 patients under EHL treatments. Mean HEAD-US score at T0 resulted 8 (range:0-16), at T24 it was 6 (range:0-16). Mean Veritas-Pro score values were 42.7 at TO, 40.1 at T12 and 38.7 at T24. At T0, EQ-5D mean utility score was 0.82 (range: 0.68-1), at T24, the mean was 0.87 (range:0.72-1). In detail, at 24 months follow-up, there was a statistically significant (p<0.05) improvement in adherence to treatment with particular reference to the dimensions of communication and skipped doses. A tendency toward improved HEAD-US score, higher adherence and better quality of life scores, was observed in particular in patients switched to EHL products at T24, at a mean of 10 months after switching (range: 6-22 months). Conclusion: Several combined measures of haemophilia treatment monitoring, allowing visual assessment of joints status and PK profile estimates by patients have here shown to improve treatment adherence and quality of life in patients with HA and HB, this may be not only related to new available treatments but also to an increased awareness and education of patients

    Minor injuries as a risk factor for venous thrombosis

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    BACKGROUND: Injuries increase the risk of venous thrombosis. So far, most research has focused on major injuries that are accompanied by other risk factors for venous thrombosis, such as plaster casts and surgery. We studied the association of venous thrombosis with common minor injuries, such as minor sural muscle ruptures and ankle sprains.\ud \ud METHODS: We performed a large, population-based, case-control study (the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis [MEGA] study), including consecutive patients with a first deep venous thrombosis of the leg or pulmonary embolism and control subjects. Participants with malignant neoplasms, those who underwent surgery, and those who had a plaster cast or extended bed rest were excluded.\ud \ud RESULTS: Of 2471 patients, 289 (11.7%), and of 3534 controls, 154 (4.4%) had a minor injury in the 3 months preceding the venous thrombosis (patients) or completion of the questionnaire (controls). Venous thrombosis was associated with previous minor injury (odds ratio adjusted for sex and age, 3.1; 95% confidence interval, 2.5-3.8). The association was strongest for injuries that occurred in the 4 weeks before thrombosis and was not apparent before 10 weeks. Thrombosis was more strongly associated with minor injuries located in the leg (odds ratio adjusted for sex and age, 5.1; 95% confidence interval, 3.9-6.7), while those located in other body parts were not associated. A 50-fold increased risk was found in factor V Leiden carriers with a leg injury compared with noncarriers without injury (odds ratio, 49.7; 95% confidence interval, 6.8-362.7).\ud \ud CONCLUSIONS: Minor injuries in the leg are associated with greater risk of venous thrombosis. Because minor injuries are common, they could be major contributors to the occurrence of venous thrombosis\u
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