Search results for "Abstraction"

Stereoselective Nucleophilic Addition Reactions of Reactive Pseudopeptides

1992

Ab initio study on the mechanism of the HCO+O2→HO2+CO reaction

2003

Abstract The gas-phase reaction HCO+O 2 →CO+HO 2 has been investigated by means of ab initio calculations. The mechanism can proceed through either a direct hydrogen abstraction or addition of O 2 to the formyl radical. The energy barriers calculated at the QCISD(T)/6-311G(2df,2p) level of theory upon QCISD/6-311G(d,p) optimized structures are, respectively, of 2.98 kcal mol −1 for the direct abstraction and of 2.26 kcal mol −1 for the addition. Thus, the results obtained show that there is not a dominant pathway in the HCO+O 2 reaction under atmospheric conditions of temperature and pressure.

Calculation of the rate constants for hydrogen abstraction reactions by Hydroperoxyl radical from Methanol, and the investigation of stability of CH3…

2020

Abstract Master equation (ME) with Lennard-Jones potential utilized to simulate the collision between CH3OH and HO2 radical in the presence of bath gas. The reaction mechanism explored through the lowest doublet potential energy surface at CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ level of theory that is barrierless and forms shallow energized intermediate at the entrance channel. The investigation of the fractional population showed that lifetime of CH3OH.HO2 intermediate (INT*) is fairly short due to its shallow depth, and at the low temperature, most reaction takes place by re-dissociation back to reactants and also when the pressure is high enough, the INT* is thermalized and comes into eq…

Reporting guidelines for health research: protocol for a cross-sectional analysis of the EQUATOR Network Library

2019

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Enseñanza de las ciencias : revista de investigación y experiencias didácticas

2021

La biodiversidad es un concepto complejo, convertido en un importante referente curricular. Esta investigación explora si un ejercicio avanzado de las competencias necesarias para hacer significativo el concepto de biodiversidad en diferentes contextos conlleva una mejora significativa de la calidad de los argumentos implicados en la toma de decisiones sobre conservación de la biodiversidad. Para ello se ha aplicado una metodología cualitativa al análisis de doce argumentos formulados por estudiantes de 1.º de Bachillerato, caracterizados por su elevada complejidad estructural, de los cuales se muestra uno a modo de ejemplo. Los resultados revelan que, a pesar del nivel de cohesión estructu…

Improving Usability of Location-Based Services with User-Centric Data Querying

2004

In this paper, we describe a computational model that produces a dataset which we consider to be an appropriate response for “give me a description of my neighborhood” type of queries in location-based services Our attempt is to reflect the abstraction ability of a specific user, and in this way to maximize the usability of the service under restrictions on data volume posed by technical, economical and cognitive factors of mobile environments We also present the results of instantiating the model for a simple LBS.

An Ambient Intelligence Architecture for Extracting Knowledge from Distributed Sensors

2009

Precisely monitoring the environmental conditions is an essential requirement for AmI projects, but the wealth of data generated by the sensing equipment may easily overwhelm the modules devoted to higher-level reasoning, clogging them with irrelevant details. The present work proposes a new approach to knowledge extraction from raw data that addresses this issue at different levels of abstraction. Wireless sensor networks are used as the pervasive sensory tool, and their computational capabilities are exploited to remotely perform preliminary data processing. A central intelligent unit subsequently extracts higher-level concepts represented in a geometrical space and carries on symbolic re…

A general theoretical framework for designing cognitive architectures: Hybrid and meta-level architectures for BICA

2012

In this paper, we will discuss hybrid architectures in which different processing modules coexist and cooperate in a principled way. A fundamental and essential role is played by modules performing meta-computation, i.e., computation about computation itself. Meta-level architectures, therefore, become an essential complement of hybrid architectures for biologically inspired cognitive architectures (BICA). Engineering and modeling BICAs is a hard task due to the lack of techniques for developing and implementing their features. We propose a new concept of intelligent agent as a useful abstraction for developing BICAs and having means for representing all the involved entities together with …

Knowledge Discovery and Digital Cartography for the ALS (Linguistic Atlas of Sicily) Project

2009

In this paper the latest developments of the ALS (Linguistic Atlas of Sicily) project are presented. The ALS project has the purpose to define methodologies and tools to allow researches in the socio-linguistic field. Different types of variables (both quantitative and qualitative) are involved. The whole framework is based on the definition of ontology-based applications for the creation, retrieval, manipulation and browsing of related data. To this aim, some mapping processes have been defined. The framework eventually shows the result in many ways including spatial maps. The on-going collaboration process is a perfect example a domain hybridizing process, enabling the training on-the-fie…

Verification of Symbolic Distributed Protocols for Networked Embedded Devices

2020

The availability of versatile and interconnected embedded devices makes it possible to build low-cost networks with a large number of nodes running even complex applications and protocols in a distributed manner. Common tools used for modeling and verification, such as simulators, present some limitations as application correctness is checked off-board and only focuses on source code. Execution in the real network is thus excluded from the early stages of design and verification. In this paper, a system for modeling and verification of symbolic distributed protocols running on embedded devices is introduced. The underlying methodology is rooted in a symbolic programming paradigm that makes …