Institution
Romanian Academy
Archive•Bucharest, Romania•
About: Romanian Academy is a archive organization based out in Bucharest, Romania. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 3662 authors who have published 10491 publications receiving 146447 citations. The organization is also known as: Academia Română & Societatea Literară Română.
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TL;DR: Interestingly enough, membrane systems without changing (evolving) the used objects and with the communication based on rules of this type are computationally complete, and this result is achieved even for pairs of communicated objects.
Abstract: In the attempt to have a framework where the computation is done by communication only, we consider the biological phenomenon of trans-membrane transport of couples of chemicals (one say symport when two chemicals pass together through a membrane, in the same direction, and antiport when two chemicals pass simultaneously through a membrane, in opposite directions). Surprisingly enough, membrane systems without changing (evolving) the used objects and with the communication based on rules of this type are computationally complete, and this result is achieved even for pairs of communicated objects (as encountered in biology). Five membranes are used; the number of membranes is reduced to two if more than two chemicals may collaborate when passing through membranes.
348 citations
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01 Oct 2020TL;DR: In this paper, the authors discuss fundamental concepts of von Neumann algebras including bounded linear operators in Hilbert spaces, finite von NEFGs, linear forms on algebra of operators, geometry of projections and classification of von NEGA in an easy to understand manner.
Abstract: Written in lucid language, this valuable text discusses fundamental concepts of von Neumann algebras including bounded linear operators in Hilbert spaces, finite von Neumann algebras, linear forms on algebra of operators, geometry of projections and classification of von Neumann algebras in an easy to understand manner. The revised text covers new material including the first two examples of factors of type II^1, an example of factor of type III and theorems for von Neumann algebras with a cyclic and separating vector. Pedagogical features including solved problems and exercises are interspersed throughout the book.
346 citations
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TL;DR: It is concluded that using higher taxonomic units in soil food web analysis is problematic and in general not consistent with nature.
Abstract: The structure of the soil food web in two beech (Fagus sylvatica) forests, the Gottinger Wald and the Solling forest (Northern Germany), was investigated using variations in tissue 15N concentrations of animal species or taxa. The Gottinger Wald is located on a limestone plateau and characterized by mull humus with high macrofauna activity, particularly of Lumbricidae, Diplopoda and Isopoda. In contrast, the Solling forest is located on a sandstone mountain range and characterized by moder humus. The soil fauna of this forest is dominated by mesofauna, particularly by Collembola, Enchytraeidae and Oribatida. In June 1995 soil fauna was sampled using heat extraction. Three soil layers were analysed at each of the sites. 15N/14N ratios of bulk material increased strongly with soil depth in both forests. This also applied to the water-soluble fraction at the Gottinger Wald, but not at the Solling. Generally, the water-soluble fraction was more enriched in 15N than the bulk materials. For most animals studied 15N/14N ratios varied little with soil depth. In both forests soil animals could be classified either as saprophages, including microphytophages, or predators. On average, the δ15N of predatory taxa (Chilopoda, Araneida, Gamasina, Staphylinidae) exceeded that of saprophagous or microphytophagous taxa (Lumbricidae, Isopoda, Diplopoda, Collembola, Oribatida, Enchytraeidae) by 4.4 and 3.9‰ for the Gottinger Wald and the Solling, respectively. We assume that most of the saprophagous or microphytophagous taxa studied consist of primary and secondary decomposers and hypothesize that predators prey more on secondary than primary decomposers. Generally, average δ15N values differed little between saprophagous (Lumbricidae, Diplopoda, Isopoda) and microphytophagous taxa (Collembola, Oribatida). The variations in δ15N values of species within these taxa consistently exceeded the variation between them, indicating that the species of each of these taxa form a continuum from primary to secondary decomposers. Also, variations in δ15N values within predatory taxa in most cases exceeded that between taxa excluding top predators like Sorex. We conclude that using higher taxonomic units in soil food web analysis is problematic and in general not consistent with nature. Higher taxonomic units may only be useful for depicting very general trophic groupings such as predators or microbi-detritivores.
343 citations
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TL;DR: This study clearly demonstrates that oxidative stress damage occurs in patients with mild cognitive impairment and AD, and some enzymatic markers of oxidative stress are similar in MCI and AD patients, suggesting that oxidative damage could be one important aspect for the onset of AD.
328 citations
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TL;DR: This immortal human keratinocyte line HaCaT is frequently used as a paradigm for skin keratinocytes in vitro because of its highly preserved differentiation capacity and qualifies this cell line as an appropriate model for elucidation of the molecular mechanisms regulating Keratinocyte growth and differentiation and for use in pharmacotoxicology.
328 citations
Authors
Showing all 3740 results
Name | H-index | Papers | Citations |
---|---|---|---|
Cristina Popescu | 74 | 285 | 18434 |
Adrian Covic | 73 | 570 | 17379 |
Gheorghe Paun | 65 | 399 | 18513 |
Floriana Tuna | 60 | 271 | 11968 |
Arto Salomaa | 56 | 374 | 17706 |
Jan A. Bergstra | 55 | 616 | 13436 |
Alexandru T. Balaban | 53 | 605 | 14225 |
Cristian Sminchisescu | 53 | 173 | 12268 |
Maya Simionescu | 47 | 192 | 10608 |
Marius Andruh | 46 | 239 | 8431 |
Werner Scheid | 46 | 518 | 9186 |
Vicenţiu D. Rădulescu | 46 | 360 | 7771 |
Cornelia Vasile | 44 | 297 | 7108 |
Irinel Popescu | 44 | 401 | 8448 |
Mihail Barboiu | 44 | 239 | 5789 |