An Extension of the Hammond Postulate. Structural Effects on the Classification of Chemical Reactions

2003 ◽  
Vol 107 (19) ◽  
pp. 3987-3994 ◽  
Author(s):  
Felipe A. Bulat ◽  
Alejandro Toro-Labbé
Author(s):  
Sanjay Ram ◽  
Somnath Pal

There are two approaches for classification of chemical reactions: Model-Driven and Data-Driven. In this paper, the authors develop an efficient algorithm based on a model-driven approach developed by Ugi and co-workers for classification of chemical reactions. The authors’ algorithm takes reaction matrix of a chemical reaction as input and generates its appropriate class as output. Reaction matrices being symmetric, matrix implementation of Ugi’s scheme using upper/lower tri-angular matrix is of O(n2) in terms of space complexity. Time complexity of similar matrix implementation is O(n4), both in worst case as well as in average case. The proposed algorithm uses two fixed size look-up tables in a novel way and requires constant space complexity. Time complexity both in worst and average cases of the algorithm is linear.


2020 ◽  
Author(s):  
Flavia Bruno

<p>I teach Natural Sciences in a Liceo Artistico, a type of secondary school in Italy. It is designed to give students the skills to progress to any university, but specifically devoted to art related topics.<br>During my career I have been following the national educational standard of the Ministero dell’Istruzione, dell’Università e della Ricerca of my Country.<br>During the years students are involved in meaningful hands-on activities   such as the study of the rocks in the country, preparation of easy chemical reactions and observations through a microscope of vegetal and animal organisms. These last ones are very interesting in a Liceo Artistico where many topics focus on the study of the morphology.<br>The theory confirms what the students learn during the practical activities, furthermore it is important to acquire a correct scientific terminology as well as to be able to express scientific issues.<br>I teach during the year the following main topics:<br>Science of Earth: the Solar System, the two motions of the Earth, structures of the Earth surface (rivers, lakes, glaciers, oceans and seas), the Earth’s Spheres, the movement of lithospheric plates.<br>Biology: the characteristics and functions of living organisms especially the cells and the biodiversity. The Evolution, Mendel’s genetic laws, organism-environment relationship in order to valorize and to maintain the biodiversity. Chemistry: state of matter, classification of matter, the Mendeleev’s Periodic Table, the main chemical reactions, atomics models, chemical bonds, chemical nomenclature.<br>The extra-curricular course proposal of my school (POFT-Piano dell’Offerta Formativa Triennale) includes my project whose title is “Science and creativity”. The achievement is to create a link between scientific subjects and the art ones in order to approach knowledge which appear distant but have really many points to share.<br>Every year some classrooms study different topics such as the Nanoparticles, Biomimetic and this year the Adaptations of the animals.<br>After a scientific conference, plastic models and graphic drawings will be realised by the students, who starting from the scientific reality, can express their creativity.<br>During the years I organize some educational visits for example to the Botanic Garden as well as to the countryside; in this way the students have opportunities to create an e-book with texts and photographs.<br>For instance two years ago my classroom created an e-book with botanical cards and the following year another one with the title “Rocce a Milano” where students took pictures and texts about this topic.<br>Many classrooms and teachers are involved in this project for example Plastic and Drawing teachers, as well as Multimedia teachers. I manage to gather the interested teachers and to realize the projects.<br>With our productions we participate in competitions and we are sometimes selected.</p>


1979 ◽  
Vol 34 (5-6) ◽  
pp. 319-329 ◽  
Author(s):  
Sabine Milz ◽  
Horst Rimpler

Abstract 12 species of the genus Verbena and one Citharexylum species have been examined for iridoids. Besides the known compounds verbenaline, hastatoside, griselinoside, lamiide, ipolamiide and brasoside, two new iridoids, pulchelloside I (1) [2] and pulchelloside II (2) [3] have been isolated from Verbena species. The structures and absolute configurations of pulchelloside I and II have been determined by spectroscopical methods and some chemical reactions. Citharexylum solanaceum has been shown to contain lamiide and durantoside I. The distribution of the iridoids is in excel­ lent agreement with the taxonomic treatment of the genus Verbena by Schauer. The taxonomic significance of our data and some data from the literature regarding the classification of the sub­ family Verbenoideae is discussed.


2008 ◽  
Vol 45 (7) ◽  
pp. 771-793 ◽  
Author(s):  
Marilyne Stains ◽  
Vicente Talanquer
Keyword(s):  

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