123 research outputs found

    A Lagrangean Relaxation Approach for the Modular Hub Location Problem

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    Hub location problems deal with the location of hub facilities and the allocation of the demand nodes to hub facilities so as to effectively route the demand between origin–destination pairs. Transportation systems such as mail, freight, passenger and even telecommunication systems most often employ hub and spoke networks to provide a strong balance between high service quality and low costs resulting in an economically competitive operation. In this study the Modular Hub Location Problem (Multiple assignments without direct connections) (MHLP-MA) is introduced. A Lagrangean relaxation method is used to approximately solve large scale instances. It relaxes a set of complicating constraints to efficiently obtain lower and upper bounds on the optimal solution of the problem. Computational experiments are performed in order to evaluate the effectiveness and limitations of the proposed model and solution method

    Study on physio-chemical properties of plasma polymerization in C2H2/N2 plasma and their impact on COL X

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    Nitrogen-containing plasma polymerization is of considerable interest for tissue engineering due to their properties on cell adhesion and mesenchymal stem cells (MSCs) response. In this study, low-pressure RF plasma of acetylene and nitrogen was used to deposit nitrogen-containing plasma polymerized coatings on several substrates. Deposition kinetics and surface characteristics of coatings were investigated in terms of RF power and gas flow ratio. OES was used to monitor the plasma process and investigate the relation between the film structure and plasma species. Presence of several bonds and low concentration of amine functional groups were determined using FTIR and Colorimetric methods. Contact angle goniometry results indicated about 30% increase in surface hydrophilicity. Stability of coatings in air and two different liquid environments was examined by repeating surface free energy measurements. Deposited films exhibited acceptable stability during the storage duration. Surface roughness measured by AFM was found to decrease with growing concentration of nitrogen. The deposition rate increased with increasing RF power and decreased with growing concentration of nitrogen. Zeta potential measurements of coatings revealed the negative potential on the surface of the thin films. Temporary suppression of collagen X in the presence of plasma coatings was confirmed by RT-PCR results

    Traffic Flow Prediction Using MI Algorithm and Considering Noisy and Data Loss Conditions: An Application to Minnesota Traffic Flow Prediction

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    Traffic flow forecasting is useful for controlling traffic flow, traffic lights, and travel times. This study uses a multi-layer perceptron neural network and the mutual information (MI) technique to forecast traffic flow and compares the prediction results with conventional traffic flow forecasting methods. The MI method is used to calculate the interdependency of historical traffic data and future traffic flow. In numerical case studies, the proposed traffic flow forecasting method was tested against data loss, changes in weather conditions, traffic congestion, and accidents. The outcomes were highly acceptable for all cases and showed the robustness of the proposed flow forecasting method

    The Study of the Relationship between the Capital Structure and the Variables of the Value-based Performance Assessment

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    Decision-making about the capital structure meaning company's finance, like other managers' decisions has an impact on the company's value. Therefore, determining an optimal capital structure in order to select financial sources is of crucial importance. To do so, the managers must be aware of the effects of influential variables on the capital structure. In order to assess the performance of business, different criteria have been presented, among which are the relationships of the value-based performance assessment. The present study aims at showing the correlation between the capital structure and the variables of the value-based performance assessment. The study is among descriptive researches and its methodology is ex post facto method. Also the hypotheses of the research have been tested using Spss19. Based on results, there is a negative and meaningful relationship between the capital structure and the variables of value-based performance assessment including Economic Value-Added (EVA), Market Value-Added (MVA), Cash Value-Added (CVA) in 219 companies listed in Tehran Stock Exchange within a time period of 5 years from 2007 to 2011. Keywords: Capital Structure, Economic Value-Added (EVA), Market Value-Added (MVA), Cash Value-Added (CVA

    Hypertension after Bilateral Nephron Sparing Surgery for Bilateral Wilms

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    Background: Nephron sparing surgery (NSS) for unilateral Wilms tumor (WT) has been debated recently and is being used to preserve kidney tissue and function. However, NSS is feasible only for selected cases with higher local relapse rates. There is a significant reduction of nephrons with the development of renal hypertension and progressive renal failure. In this paper, we have analyzed outcomes after bilateral partial nephrectomy (PN) and unilateral partial plus contralateral total nephrectomy in our patients with bilateral WT.Methods: We have analyzed our four patients (8 kidneys) with bilateral WT and 8 unilateral complete resection. Kidney size was measured using volumetric analysis computed tomography scan imaging. The patients were matched with children who had undergone imaging of the abdomen for other malignancies.Results: Mean kidney volumes after unilateral partial plus total contralateral nephrectomy (60.9 cm3) were significantly greater than the reference kidneys. Total kidney volume was significantly larger after bilateral PN (98.1 cm3) versus unilateral partial plus total contralateral nephrectomy (60.9 cm3).Conclusions: Our findings suggest that patients with bilateral WT benefit from bilateral NSS. Hypertension is less common after bilateral PN. However, rates of local relapse or disease associated death are separately between the groups

    Prevalence of anti-HCV antibody and related risk factors among bleeding disorder patients in Yazd province of Iran

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    زمینه و هدف: مصرف جایگزین درمانی خون و فرآورده های خونی غربال نشده یا فاکتورهای انعقادی تغلیظ شده ویروس زدایی نشده در بیماران اختلال انعقادی خطر ابتلا به هپاتیت C را در آنها ایجاد می کند. مطالعه حاضر به منظور بررسی فراوانی آنتی بادی بر علیه ویروس هپاتیت C (anti-HCV Ab) و فاکتورهای خطر مربوطه در بیماران اختلال انعقادی استان یزد انجام شد. روش بررسی: در این مطالعه توصیفی-تحلیلی که به روش سرشماری در تابستان 1385 انجام شد، پس از جمع آوری اطلاعات پرسشنامه ای، از 77 بیمار نمونه خون گرفته شد. نمونه های پلاسما با کیت الیزا از نظر آنتی بادی بر علیه ویروس هپاتیت C و سپس نمونه های مثبت با روش تست RIBA (Recombinant Immonoblot Assay) تایید شدند. داده ها با استفاده از آزمون های آماری کای دو و آنالیز رگرسیون لجستیک مورد تجزیه و تحلیل قرار گرفتند. یافته ها: فراوانی آنتی بادی بر علیه ویروس هپاتیت ‍‍C معادل 4/49 (38 بیمار) بدست آمد. بین داشتن فرم شدید بیماری (از نظر نیاز به فرآورده های خونی) (01/0

    A Model for Supply Chain Performance of Electronics Industry in Malaysia

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    Abstract-During the last decades supply chain issues have attracted researchers and industrialists' attention especially in manufacturing-based industries. Enhancing supply chain performance can significantly affect firm's competitive position within competitive markets and provide the enterprise with competitive advantage over its rivals. Based on the existing literature in the context of supply chain, this study tries to present a model for supply chain performance. The conceptual model presented in this study consists of supply chain design, information sharing, flexibility, delivery and supply chain performance and the electronics industry in Malaysia is selected as the population of this study in order to test the model by using the data collected from the industry. The model is investigated through path analysis and then by using factor analysis, Friedman test and paired sign test the variables are identified and the priority of each variable is investigated. The model presented by this study can be employed as a platform by Malaysian electronics manufacturing companies in order to improve their supply chain performance and obtain competitive advantage within local and foreign markets

    Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

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    Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI

    Effect of Intermediate-Dose vs Standard-Dose Prophylactic Anticoagulation on Thrombotic Events, Extracorporeal Membrane Oxygenation Treatment, or Mortality among Patients with COVID-19 Admitted to the Intensive Care Unit: The INSPIRATION Randomized Clinical Trial

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    Importance: Thrombotic events are commonly reported in critically ill patients with COVID-19. Limited data exist to guide the intensity of antithrombotic prophylaxis. Objective: To evaluate the effects of intermediate-dose vs standard-dose prophylactic anticoagulation among patients with COVID-19 admitted to the intensive care unit (ICU). Design, Setting, and Participants: Multicenter randomized trial with a 2 � 2 factorial design performed in 10 academic centers in Iran comparing intermediate-dose vs standard-dose prophylactic anticoagulation (first hypothesis) and statin therapy vs matching placebo (second hypothesis; not reported in this article) among adult patients admitted to the ICU with COVID-19. Patients were recruited between July 29, 2020, and November 19, 2020. The final follow-up date for the 30-day primary outcome was December 19, 2020. Interventions: Intermediate-dose (enoxaparin, 1 mg/kg daily) (n = 276) vs standard prophylactic anticoagulation (enoxaparin, 40 mg daily) (n = 286), with modification according to body weight and creatinine clearance. The assigned treatments were planned to be continued until completion of 30-day follow-up. Main Outcomes and Measures: The primary efficacy outcome was a composite of venous or arterial thrombosis, treatment with extracorporeal membrane oxygenation, or mortality within 30 days, assessed in randomized patients who met the eligibility criteria and received at least 1 dose of the assigned treatment. Prespecified safety outcomes included major bleeding according to the Bleeding Academic Research Consortium (type 3 or 5 definition), powered for noninferiority (a noninferiority margin of 1.8 based on odds ratio), and severe thrombocytopenia (platelet count <20 �103/µL). All outcomes were blindly adjudicated. Results: Among 600 randomized patients, 562 (93.7) were included in the primary analysis (median interquartile range age, 62 50-71 years; 237 42.2% women). The primary efficacy outcome occurred in 126 patients (45.7%) in the intermediate-dose group and 126 patients (44.1%) in the standard-dose prophylaxis group (absolute risk difference, 1.5% 95% CI,-6.6% to 9.8%; odds ratio, 1.06 95% CI, 0.76-1.48; P =.70). Major bleeding occurred in 7 patients (2.5%) in the intermediate-dose group and 4 patients (1.4%) in the standard-dose prophylaxis group (risk difference, 1.1% 1-sided 97.5% CI,-� to 3.4%; odds ratio, 1.83 1-sided 97.5% CI, 0.00-5.93), not meeting the noninferiority criteria (P for noninferiority >.99). Severe thrombocytopenia occurred only in patients assigned to the intermediate-dose group (6 vs 0 patients; risk difference, 2.2% 95% CI, 0.4%-3.8%; P =.01). Conclusions and Relevance: Among patients admitted to the ICU with COVID-19, intermediate-dose prophylactic anticoagulation, compared with standard-dose prophylactic anticoagulation, did not result in a significant difference in the primary outcome of a composite of adjudicated venous or arterial thrombosis, treatment with extracorporeal membrane oxygenation, or mortality within 30 days. These results do not support the routine empirical use of intermediate-dose prophylactic anticoagulation in unselected patients admitted to the ICU with COVID-19. Trial Registration: ClinicalTrials.gov Identifier: NCT04486508. © 2021 American Medical Association. All rights reserved
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