Results 71 to 80 of about 2,791,202 (312)

Relatively divisible and relatively flat objects in exact categories [PDF]

open access: yesarXiv, 2018
We introduce and study relatively divisible and relatively flat objects in exact categories in the sense of Quillen. For every relative cotorsion pair $(\mathcal{A},\mathcal{B})$ in an exact category $\mathcal{C}$, $\mathcal{A}$ coincides with the class of relatively flat objects of $\mathcal{C}$ for some relative projectively generated exact structure,
arxiv  

On morphisms of relative toposes [PDF]

open access: yesarXiv, 2023
We systematically investigate the functors between sites which induce morphisms of relative toposes. In particualar, we establish a relative version of Diaconescu's theorem, characterizing the relative geometric morphisms towards a relative sheaf topos in terms of a notion of flat (equivalently, filtered) functor relative to the base topos.
arxiv  

The carboxylate “gripper” of the substrate is critical for C‐4 stereo‐inversion by UDP‐glucuronic acid 4‐epimerase

open access: yesFEBS Letters, EarlyView.
UDP‐glucuronic acid 4‐epimerase (UGAepi) catalyzes NAD+‐dependent interconversion of UDP‐glucuronic acid (UDP‐GlcA) and UDP‐galacturonic acid (UDP‐GalA) via C4‐oxidation, 4‐keto‐intermediate rotation, and C4‐reduction. Here, Borg et al. examined the role of the substrate's carboxylate group in the enzymic mechanism by analyzing NADH‐dependent reduction
Annika J. E. Borg   +2 more
wiley   +1 more source

A combination theorem for relatively hyperbolic groups and finite relative height of splitting [PDF]

open access: yesarXiv, 2022
In this paper, we prove a combination theorem for a relatively acylindrical graph of relatively hyperbolic groups (Theorem 1.1). Here, we are extending the technique of [Tom21] and constructing Bowditch boundary of the fundamental group of graph of groups.
arxiv  

In vivo evidence for glycyl radical insertion into a catalytically inactive variant of pyruvate formate‐lyase

open access: yesFEBS Letters, EarlyView.
Dimeric pyruvate formate‐lyase cleaves pyruvate using a radical‐based mechanism. G734 serves as a radical storage location, and the radical is transferred to the catalytic C419 residue. Mutation of the C418‐C419 pair causes loss of enzyme activity, but does not impede radical introduction onto G734. Therefore, cis‐ but not trans‐radical transfer occurs
Michelle Kammel   +2 more
wiley   +1 more source

The Meaning of Rotation in the Special Theory of Relativity.

open access: yesProceedings of the National Academy of Sciences of the United States of America, 1922
The novelty of the special theory of relativity consists in its replacing the equations for translation given by the Newtonian theory by the Lorentz transformations.
Philip Franklin
semanticscholar   +1 more source

Shape Dynamics [PDF]

open access: yesarXiv, 2013
Barbour's formulation of Mach's principle requires a theory of gravity to implement local relativity of clocks, local relativity of rods and spatial covariance. It turns out that relativity of clocks and rods are mutually exclusive. General Relativity implements local relativity of clocks and spatial covariance, but not local relativity of rods.
arxiv  

Design, analysis and reformulation of a didactic sequence for teaching the special theory of relativity in high school

open access: yesRevista Brasileira de Ensino de Física
In this work, we design, implement and analyze a didactic sequence for the teaching of the basic topics of special relativity theory in high school. The sequence proposes a series of situations, specially designed to allow the emergence of the central ...
María Rita Otero   +2 more
doaj   +1 more source

Physical Justifications and Possible Astrophysical Manifestations of the Projective Theory of Relativity

open access: yesUniverse, 2019
The ‘projective theory of relativity’ is a theory developed historically by Oswald Veblen and Banesh Hoffmann, Jan Arnoldus Schouten and David van Dantzig.
Jacques L. Rubin
doaj   +1 more source

Evolutionary interplay between viruses and R‐loops

open access: yesFEBS Letters, EarlyView.
Viruses interact with specialized nucleic acid structures called R‐loops to influence host transcription, epigenetic states, latency, and immune evasion. This Perspective examines the roles of R‐loops in viral replication, integration, and silencing, and how viruses co‐opt or avoid these structures.
Zsolt Karányi   +4 more
wiley   +1 more source

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