Model reduction method for a class of 2-D systems, A

Includes bibliographical references.A decomposition-aggregation scheme for reduction of dimensionality for a class of 2-D systems is introduced. This method, which is based upon the extension of the singular perturbation method in two dimensions, is used to decompose the original 2-D system into two reduced-order 2-D subsystems. These reduced order subsystems are shown to effectively capture the dynamical behavior of the original full-order system. Two numerical examples are provided that indicate the effectiveness of this method when used in image modeling applications.This work was supported in part by the Natural Sciences and Engineering Research Council of Canada, and by Fonds Pour la Formation de Chercheurs et L'aide la Recherche, Programme E'tablissment de Nouveaux Chercheurs

Reduced order strip Kalman filtering using singular perturbation method

Includes bibliographical references.Strip Kalman filtering for restoration of images degraded by linear shift invariant (LSI) blur and additive white Gaussian (WG) noise is considered. The image process is modeled by a 1-D vector autoregressive (AR) model in each strip. It is shown that the composite dynamic model that is obtained by combining the image model and the blur model takes the form of a singularly perturbed system owing to the strong-weak correlation effects within a window. The time scale property of the singularly perturbed system is then utilized to decompose the original system into reduced order subsystems which closely capture the behavior of the full order system. For these subsystems the relevant Kalman filtering equations are given which provide the suboptimal filtered estimates of the image and the one-step prediction estimates of the blur needed for the next stage. Simulation results are also provided

Examining clinical decision support integrity: is clinician self-reported data entry accurate?

The aim of this study was to assess the accuracy of clinician-entered data in imaging clinical decision support (CDS). We used CDS-guided CT angiography (CTA) for pulmonary embolus (PE) in the emergency department as a case example because it required clinician entry of d-dimer results which could be unambiguously compared with actual laboratory values. Of 1296 patients with CTA orders for suspected PE during 2011, 1175 (90.7%) had accurate d-dimer values entered. In 55 orders (4.2%), incorrectly entered data shielded clinicians from intrusive computer alerts, resulting in potential CTA overuse. Remaining data entry errors did not affect user workflow. We found no missed PEs in our cohort. The majority of data entered by clinicians into imaging CDS are accurate. A small proportion may be intentionally erroneous to avoid intrusive computer alerts. Quality improvement methods, including academic detailing and improved integration between electronic medical record and CDS to minimize redundant data entry, may be necessary to optimize adoption of evidence presented through CDS

Thermomechanical buckling analysis of the e&p-fgm beams integrated by nanocomposite supports immersed in a hygrothermal environment

Due to the widespread use of sandwich structures in many industries and the importance of understanding their mechanical behavior, this paper studies the thermomechanical buckling behavior of sandwich beams with a functionally graded material (FGM) middle layer and two composite external layers. Both composite skins are made of Poly(methyl methacrylate) (PMMA) reinforced by carbon-nano-tubes (CNTs). The properties of the FGM core are predicted through an exponential-law and power-law theory (E&P), whereas an Eshelby–Mori–Tanaka (EMT) formulation is applied to capture the mechanical properties of the external layers. Moreover, different high-order displacement fields are combined with a virtual displacement approach to derive the governing equations of the problem, here solved analytically based on a Navier-type approximation. A parametric study is performed to check for the impact of different core materials and CNT concentrations inside the PMMA on the overall response of beams resting on a Pasternak substrate and subjected to a hygrothermal loading. This means that the sensitivity analysis accounts for different displacement fields, hygrothermal environments, and FGM theories, as a novel aspect of the present work. Our results could be replicated in a computational sense, and could be useful for design purposes in aerospace industries to increase the tolerance of target productions, such as aircraft bodies

Effect of alendronate on post-traumatic osteoarthritis induced by anterior cruciate ligament rupture in mice.

IntroductionPrevious studies in animal models of osteoarthritis suggest that alendronate (ALN) has antiresorptive and chondroprotective effects, and can reduce osteophyte formation. However, these studies used non-physiologic injury methods, and did not investigate early time points during which bone is rapidly remodeled prior to cartilage degeneration. The current study utilized a non-invasive model of knee injury in mice to investigate the effect of ALN treatment on subchondral bone changes, articular cartilage degeneration, and osteophyte formation following injury.MethodsNon-invasive knee injury via tibial compression overload or sham injury was performed on a total of 90 mice. Mice were treated with twice weekly subcutaneous injections of low-dose ALN (40 μg/kg/dose), high-dose ALN (1,000 μg/kg/dose), or vehicle, starting immediately after injury until sacrifice at 7, 14 or 56 days. Trabecular bone of the femoral epiphysis, subchondral cortical bone, and osteophyte volume were quantified using micro-computed tomography (μCT). Whole-joint histology was performed at all time points to analyze articular cartilage and joint degeneration. Blood was collected at sacrifice, and serum was analyzed for biomarkers of bone formation and resorption.ResultsμCT analysis revealed significant loss of trabecular bone from the femoral epiphysis 7 and 14 days post-injury, which was effectively prevented by high-dose ALN treatment. High-dose ALN treatment was also able to reduce subchondral bone thickening 56 days post-injury, and was able to partially preserve articular cartilage 14 days post-injury. However, ALN treatment was not able to reduce osteophyte formation at 56 days post-injury, nor was it able to prevent articular cartilage and joint degeneration at this time point. Analysis of serum biomarkers revealed an increase in bone resorption at 7 and 14 days post-injury, with no change in bone formation at any time points.ConclusionsHigh-dose ALN treatment was able to prevent early trabecular bone loss and cartilage degeneration following non-invasive knee injury, but was not able to mitigate long-term joint degeneration. These data contribute to understanding the effect of bisphosphonates on the development of osteoarthritis, and may support the use of anti-resorptive drugs to prevent joint degeneration following injury, although further investigation is warranted

Assessing 2 D-dimer age-adjustment strategies to optimize computed tomographic use in ED evaluation of pulmonary embolism

STUDY OBJECTIVE: Validate the sensitivity and specificity of 2 age adjustment strategies for d-dimer values in identifying patients at risk for pulmonary embolism (PE) compared with traditional D-dimer cutoff value (500 ng/mL) to decrease inappropriate computed tomography pulmonary angiography (CTPA) use. METHODS: This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study included all adult emergency department patients evaluated for PE over a 32-month period (1/1/11-8/30/13). Only patients undergoing CTPA and D-dimer testing were included. We used a validated natural language processing algorithm to parse CTPA radiology reports and determine the presence of acute PE. Outcome measures were sensitivity and specificity of 2 age-adjusted D-dimer cutoffs compared with the traditional cutoff. We used chi2 tests with proportional analyses to assess differences in traditional and age-adjusted (agex10 ng/mL) D-dimer cutoffs, adjusting both by decade and by year. RESULTS: A total 3063 patients with suspected PE were evaluated by CTPA during the study period, and 1055 (34%) also received d-dimer testing. The specificity of age-adjusted D-dimer values was similar or higher for each age group studied compared with traditional cutoff, without significantly compromising sensitivity. Overall, had decade age-adjusted cutoffs been used, 37 CTPAs could have been avoided (19.6% of 189 patients aged \u3e60 years with Wells score50 years with Wells scor

Effect of plant cover on presence of Black Francolin (Francolinus francolinus) in Khouzestan Province, Southwestern Iran

Three of 6 subspecies of black francolins (Francolinus francolinus), are found throughout Iran. Habitat destruction and indiscriminate hunting as well as agricultural pesticides are among the most crucial factors threatening the populations of these birds in Khouzestan Province, southwestern Iran. Using plot sampling, this study aims to investigate different vegetative factors including plant species, percentage of species presence and dominant plant cover height on francolin presence. Sampling was carried out throughout 5 presence areas of black francolin and 2 areas lacking francolins (control areas). Results showed that frequency of Camels thorn (Alhagi cameloram), Cashew (Prosopis farcta) and African Salsola (Suaeda fruticosa) were higher in presence areas compared with other plant species. Using One Way ANOVA, it was determined that there was no significant difference between plant cover percent (P = 0.279) and dominant plant cover height (P = 0.316). However, difference of these two mentioned factors were significant in 4 seasons (P = 000 for cover height and P = 0.001 for cover percent). In fact, the highest black francolin presence was recorded at 15 – 67 and 4 – 48 for cover percent and cover height classes respectively

Quasi-3D Hyperbolic Shear Deformation Theory for the Free Vibration Study of Honeycomb Microplates with Graphene Nanoplatelets-Reinforced Epoxy Skins

A novel quasi-3D hyperbolic shear deformation theory (QHSDT) with five unknowns is here employed, together with the Hamilton's principle and the modified couple stress theory (MCST) to analyze the vibrational behavior of rectangular micro-scale sandwich plates resting on a visco-Pasternak foundation. The sandwich structure features a Nomex or Glass phenolic honeycomb core, and two composite face sheets reinforced with graphene nanoplatelets (GPLs). The effective properties of both face sheets are evaluated by means of the Halpin-Tsai and extended rule of mixture (ERM) micromechanical schemes. The governing equations of the problem are derived by applying the Hamilton's principle, whose solutions are determined theoretically according to a classical Navier-type procedure. A parametric study checks for the effect of different material properties, length-scale parameters, foundation parameters and geometrical properties of the honeycomb cells, and the reinforcing GPLs, on the vibration response of the layered structure, which can be of great interest for many modern engineering applications and their optimization design

Density and dry weight of pigweed by various weed control methods and various resources of nitrogen fertilizer in corn forage farm

This study evaluates effects of various weeds control methods and nitrogen fertilizer resources on density and dry weight of pigweed and the performance of corn forage as factorial in full random block design with 3 repetitions in research farm of Ferdowsi Mashhad University in 2014. The test treatments include weed control methods such as chemical control, compound (mechanical+ chemical) control, and no control and types of nitrogen fertilizer including (urea, sulfate ammonium, nitrate calcium, nitrate ammonium, and nonusing fertilizer). Density and dry weight of pigweed was measured four times in growing season to determine changes procedure. In the Corn primary stage, the performance of wet forage was also measured. The obtained results from test showed that forage performance at the end of growing season, and density and dry weight of pigweed after 60 days of planting were significantly influenced by control methods, type of nitrogen fertilizer, and interaction of control methods and type of nitrogen fertilizer. (P>0.01) the highest forage performance was obtained in compound control method and nitrate calcium fertilizer treatment with approximate weight of 12072kg/hec.In no control and studied fertilizers treatment in test, the pigweed density has stayed constant with soft descending slope 20 days after planting so on, and its weight increased until 60 days of planting and then decreased until the growing season.Keywords: Compound Control, Nitrogen Fertilizer Resource, Pigweed, Corn Forag

The use of decision support to measure documented adherence to a national imaging quality measure

RATIONALE AND OBJECTIVES: Present methods for measuring adherence to national imaging quality measures often require a resource-intensive chart review. Computerized decision support systems may allow for automated capture of these data. We sought to determine the feasibility of measuring adherence to a national quality measure (NQM) regarding computed tomography pulmonary angiograms (CTPAs) for pulmonary embolism using measure-targeted clinical decision support and whether the associated increased burden of data captured required by this system would affect the use and yield of CTs. MATERIALS AND METHODS: This institutional review board-approved prospective cohort study enrolled patients from September 1, 2009, through November 30, 2011, in the emergency department (ED) of a 776-bed quaternary-care adults-only academic medical center. Our intervention consisted of an NQM-targeted clinical decision support tool for CTPAs, which required mandatory input of the Wells criteria and serum D-dimer level. The primary outcome was the documented adherence to the quality measure prior and subsequent to the intervention, and the secondary outcomes were the use and yield of CTPAs. RESULTS: A total of 1209 patients with suspected PE (2.0% of 58,795 ED visits) were imaged by CTPA during the 12-month control period, and 1212 patients were imaged in the 12 months after the quarter during which the intervention was implemented (2.0% of 59,478 ED visits, P = .84). Documented baseline adherence to the NQM was 56.9% based on a structured review of the provider notes. After implementation, documented adherence increased to 75.6% (P \u3c .01). CTPA yield remained unchanged and was 10.4% during the control period and 10.1% after the intervention (P = .88). CONCLUSIONS: Implementation of a clinical decision support tool significantly improved documented adherence to an NQM, enabling automated measurement of provider adherence to evidence without the need for resource-intensive chart review. It did not adversely affect the use or yield of CTPAs