3,637 research outputs found
The Central Symbiosis of Molecular Biology: Molecules in Mutualism.
As illustrated by the mitochondrion and the eukaryotic cell, little in biology makes sense except in light of mutualism. Mutualisms are persistent, intimate, and reciprocal exchanges; an organism proficient in obtaining certain benefits confers those on a partner, which reciprocates by conferring different benefits. Mutualisms (i) increase fitness, (ii) inspire robustness, (iii) are resilient and resistant to change, (iv) sponsor co-evolution, (v) foster innovation, and (vi) involve partners that are distantly related with contrasting yet complementary proficiencies. Previous to this work, mutualisms were understood to operate on levels of cells, organisms, ecosystems, and even societies and economies. Here, the concepts of mutualism are extended to molecules and are seen to apply to the relationship between RNA and protein. Polynucleotide and polypeptide are Molecules in Mutualism. RNA synthesizes protein in the ribosome and protein synthesizes RNA in polymerases. RNA and protein are codependent, and trade proficiencies. Protein has proficiency in folding into complex three-dimensional states, contributing enzymes, fibers, adhesives, pumps, pores, switches, and receptors. RNA has proficiency in direct molecular recognition, achieved by complementary base pairing interactions, which allow it to maintain, record, and transduce information. The large phylogenetic distance that characterizes partnerships in organismal mutualism has close analogy with large distance in chemical space between RNA and protein. The RNA backbone is anionic and self-repulsive and cannot form hydrophobic structural cores. The protein backbone is neutral and cohesive and commonly forms hydrophobic cores. Molecules in Mutualism extends beyond RNA and protein. A cell is a consortium of molecules in which nucleic acids, proteins, polysaccharides, phospholipids, and other molecules form a mutualism consortium that drives metabolism and replication. Analogies are found in systems such as stromatolites, which are large consortia of symbiotic organisms. It seems reasonable to suggest that 'polymers in mutualism relationships' is a useful and predictive definition of life
Regression Filtration with Resetting to Provide Exponential Convergence of MRAC for Plants with Jump Change of Unknown Parameters
This paper proposes a new method to provide the exponential convergence of
both the parameter and tracking errors of the composite adaptive control system
without the requirement of the regressor persistent excitation (PE). Instead,
the composite adaptation law obtained in this paper requires the regressor to
be finitely exciting (FE) to guarantee the above-mentioned properties. Unlike
known solutions, not only does it relax the PE requirement, but also it
functions effectively under the condition of a jump change of the plant
uncertainty parameters. To derive such an adaptation law, an integral filter of
regressor with damping and resetting is proposed. It provides the required
properties of the control system, and its output signal is bounded even when
its input is subjected to noise and disturbances. A rigorous analytical proof
of all mentioned properties of the developed adaptation law is presented. Such
law is compared with the known composite ones relaxing the PE requirement. The
wing-rock problem is used for the modeling of the developed composite MRAC
system. The obtained results fully support the theoretical analysis and
demonstrate the advantages of the proposed method.Comment: 12 pages, 3 figure
Searching for Truth in Civil Process: The Netherlands and Russia
This article examines the search for truth by the civil law courts in The Netherlands and Russia, and elucidates three basic questions in that respect: 1) should civil law courts seek for truth in civil process; 2) how must this truth be perceived; and 3) how do courts seek for truth? The Dutch approach to these questions is basically that no justice can be done when there has not at least been undertaken a serious effort to find out the truth, while at the same time acknowledging that seeking for truth has less to do with the final result than with the attitude of the court in its quest for a just decision. In their search for truth – by establishing the correct facts – Dutch courts apply a balanced methodology. Russian civil courts take the position that, although are not required to, they think they should search for truth in the sense that it correctly reflects objective reality. It may well be that Russian civil procedure puts in theory a goal of finding objective truth but, while having no objective instrument for that, does so in the most subjective way possible. Dutch methodology may well be the one needed for the Russian courts.
Natural Language Processing with Small Feed-Forward Networks
We show that small and shallow feed-forward neural networks can achieve near
state-of-the-art results on a range of unstructured and structured language
processing tasks while being considerably cheaper in memory and computational
requirements than deep recurrent models. Motivated by resource-constrained
environments like mobile phones, we showcase simple techniques for obtaining
such small neural network models, and investigate different tradeoffs when
deciding how to allocate a small memory budget.Comment: EMNLP 2017 short pape
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