scholarly journals To the Question of Local Extension of the Parallel Translations Group of Three-Dimensional Space

Author(s):  
В. А. Кыров

В современной геометрии актуальна задача расширения транзитивной группы Ли $G$, действующей в~многообразии $M$. Под расширением транзитивной группы Ли $G$ понимается группа Ли $G_1$, содержащая $G$ в виде подгруппы Ли и тоже транзитивная на $M$, причем ограничение этого транзитивного действия на $G$ дает исходное транзитивное действие группы Ли~$G$. В~частности, можно говорить о расширении группы параллельных переносов трехмерного пространства $R^3$. В данной работе ставится задача о нахождении всех локально дважды транзитивных расширений группы параллельных переносов трехмерного пространства. Эта задача сводится к вычислению алгебр Ли локально дважды транзитивных расширений группы параллельных переносов. Базисные операторы таких алгебр Ли находятся из решений особых систем трех дифференциальных уравнений. Доказано, что матрицы коэффициентов этих систем дифференциальных уравнений коммутируют между собой. Первая матрица приводится к жордановой форме, а остальные две матрицы упрощаются используя коммутативность и применяя допустимые преобразования. В результате имеем шесть типов алгебр Ли. Нахождению явных видов таких алгебр Ли и им соответствующих локальных групп Ли преобразований трехмерного пространства будет посвящена отдельная работа.

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.


2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>


Author(s):  
Raimo Hartmann ◽  
Hannah Jeckel ◽  
Eric Jelli ◽  
Praveen K. Singh ◽  
Sanika Vaidya ◽  
...  

AbstractBiofilms are microbial communities that represent a highly abundant form of microbial life on Earth. Inside biofilms, phenotypic and genotypic variations occur in three-dimensional space and time; microscopy and quantitative image analysis are therefore crucial for elucidating their functions. Here, we present BiofilmQ—a comprehensive image cytometry software tool for the automated and high-throughput quantification, analysis and visualization of numerous biofilm-internal and whole-biofilm properties in three-dimensional space and time.


i-com ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 67-85
Author(s):  
Matthias Weise ◽  
Raphael Zender ◽  
Ulrike Lucke

AbstractThe selection and manipulation of objects in Virtual Reality face application developers with a substantial challenge as they need to ensure a seamless interaction in three-dimensional space. Assessing the advantages and disadvantages of selection and manipulation techniques in specific scenarios and regarding usability and user experience is a mandatory task to find suitable forms of interaction. In this article, we take a look at the most common issues arising in the interaction with objects in VR. We present a taxonomy allowing the classification of techniques regarding multiple dimensions. The issues are then associated with these dimensions. Furthermore, we analyze the results of a study comparing multiple selection techniques and present a tool allowing developers of VR applications to search for appropriate selection and manipulation techniques and to get scenario dependent suggestions based on the data of the executed study.


2021 ◽  
Vol 1111 (1) ◽  
pp. 012034
Author(s):  
N A Maksimov ◽  
K Zhigalov ◽  
A V Gorban ◽  
I V Ignatev

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 20100-20116
Author(s):  
Xianjin Zhou ◽  
Fei Gao ◽  
Xi Fang ◽  
Zehong Lan

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