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Identifying the Prognosis Factors in Death after Liver Transplantation via Adaptive LASSO in Iran
No full textDespite the widespread use of liver transplantation as a routine therapy in liver diseases, the effective factors on its outcomes are still controversial. This study attempted to identify the most effective factors on death after liver transplantation. For this purpose, modified least absolute shrinkage and selection operator (LASSO), called Adaptive LASSO, was utilized. One of the best advantages of this method is considering high number of factors. Therefore, in a historical cohort study from 2008 to 2013, the clinical findings of 680 patients undergoing liver transplant surgery were considered. Ridge and Adaptive LASSO regression methods were then implemented to identify the most effective factors on death. To compare the performance of these two models, receiver operating characteristic (ROC) curve was used. According to the results, 12 factors in Ridge regression and 9 ones in Adaptive LASSO regression were significant. The area under the ROC curve (AUC) of Adaptive LASSO was equal to 89% (95% CI: 86%-91%), which was significantly greater than Ridge regression (64%, 95% CI: 61%-68%) ( < 0.001). As a conclusion, the significant factors and the performance criteria revealed the superiority of Adaptive LASSO method as a penalized model versus traditional regression model in the present study
MODELLING HETEROGENEOUS TRAFFIC SYSTEMS: CONCEPTS AND METHODOLOGY
No full textAbstract Models in general, enable understanding of concepts and systems with ease. They are highly useful in design, prediction, and evaluation of alternatives quickly, economically, and harmlessly. Different types of models are developed such as, physical, symbolic and mental models, depending upon the nature of the system. Experiments with models often lead to generation of new hypothesis and formalization of knowledge about systems. Road traffic flow being stochastic, they are too complex to be represented by a reasonable mathematical model. Hence, simulation technique is often used to model road traffic phenomena. Computer simulation models can play an important role in the analysis and assessment of the traffic-flow characteristics under heterogeneous traffic conditions such as the ones prevailing on Indian roads. An appropriate simulation framework to model heterogeneous traffic flow has been proposed here after description on certain conceptual aspects of modelling. The proposed methodology, when applied to field conditions, was found to be valid
Instructions for the Preparation of Camera-Ready Manuscripts for Proceedings of International Congress on Laser Precision Microfabrication (LPM2004)
No full textABSTRACT The abstract should not exceed 200 words in length, and should be placed two lines below affiliations. These pages provide you with an example of the layout and style for 100 % reproduction, with which we require you to adopt during the preparation of your paper
Esterification of Waste Fatty Acid from Palm Oil Refining Process into Biodiesel by Heterogeneous Catalysis: Fuel Properties of B10, B20 Blends
No full textAbstract: This study presented the preparation of Biodiesel B100 from waste fatty acid by heterogeneous catalysis process and the evaluation of the properties of B10, B20 blends. Efficiency of esterification of waste fatty acid into B100 was 98.91% over 3 cycles. Biodiesel B100 was satisfactory according to ASTM D6751, the American biodiesel standard. These methyl esters can be used to substitute diesel. However, the methyl esters obtained from waste fatty acid had a low oxidative stability and high cloud point. Therefore, with a high percentage of biodiesel (10÷20%), it is necessary to add additives into the blends for changing these disadvantages in accordance with ASTM D 7467
Design of Pd-Based Bimetallic Catalysts for ORR: A DFT Calculation Study
No full textDeveloping Pd-lean catalysts for oxygen reduction reaction (ORR) is the key for large-scale application of proton exchange membrane fuel cells (PEMFCs). In the present paper, we have proposed a multiple-descriptor strategy for designing efficient and durable ORR Pd-based alloy catalysts. We demonstrated that an ideal Pd-based bimetallic alloy catalyst for ORR should possess simultaneously negative alloy formation energy, negative surface segregation energy of Pd, and a lower oxygen binding ability than pure Pt. By performing detailed DFT calculations on the thermodynamics, surface chemistry and electronic properties of Pd-M alloys, Pd-V, Pd-Fe, Pd-Zn, Pd-Nb, and Pd-Ta, are identified theoretically to have stable Pd segregated surface and improved ORR activity. Factors affecting these properties are analyzed. The alloy formation energy of Pd with transition metals M can be mainly determined by their electron interaction. This may be the origin of the negative alloy formation energy for Pd-M alloys. The surface segregation energy of Pd is primarily determined by the surface energy and the atomic radius of M. The metals M which have smaller atomic radius and higher surface energy would tend to favor the surface segregation of Pd in corresponding Pd-M alloys
A New Framework for Learning Approaches toward Social Evolution of Organizations
Get PDFAbstract This paper addresses a gap in the literature concerning suitability of organizational learning approaches in facing social responsibility challenges, and proposes a developed framework that could proactively bridge this gap. A new framework is designed in order to gain insight on the relationships between the typical organizational learning approaches-which have been discussed extensively so far in the literature-and the brandnew concept of civil learning come out of Corporate Social Responsibility (CSR) studies in very recent years. Comparative analysis is employed to identify well-adjusted organizational learning approaches toward social evolution of organizations. Indeed we are looking to propose a specific learning framework for the firms that are tackling with CSR issues. Hence, we qualitatively bridge between organizational learning models and social learning approaches in order to foster a more advanced framework which recommends the employment of specific learning methods and styles to deal with CSR challenges based on the features of the firm and its business contextual considerations. JEL Classification: M10, M1
Systematic Electrical Disconnection of Superior Vena Cava in Addition to Pulmonary Vein Ablation: Is It Worthwhile?
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