Bottlenecks to vibrational energy flow in OCS: Structures and mechanisms

Finding the causes for the nonstatistical vibrational energy relaxation in the planar carbonyl sulfide (OCS) molecule is a longstanding problem in chemical physics: Not only is the relaxation incomplete long past the predicted statistical relaxation time, but it also consists of a sequence of abrupt transitions between long-lived regions of localized energy modes. We report on the phase space bottlenecks responsible for this slow and uneven vibrational energy flow in this Hamiltonian system with three degrees of freedom. They belong to a particular class of two-dimensional invariant tori which are organized around elliptic periodic orbits. We relate the trapping and transition mechanisms with the linear stability of these structures.Comment: 13 pages, 13 figure

Gaussian excitations model for glass-former dynamics and thermodynamics

We describe a model for the thermodynamics and dynamics of glass-forming liquids in terms of excitations from an ideal glass state to a Gaussian manifold of configurationally excited states. The quantitative fit of this three parameter model to the experimental data on excess entropy and heat capacity shows that ``fragile'' behavior, indicated by a sharply rising excess heat capacity as the glass transition is approached from above, occurs in anticipation of a first-order transition -- usually hidden below the glass transition -- to a ``strong'' liquid state of low excess entropy. The dynamic model relates relaxation to a hierarchical sequence of excitation events each involving the probability of accumulating sufficient kinetic energy on a separate excitable unit. Super-Arrhenius behavior of the relaxation rates, and the known correlation of kinetic with thermodynamic fragility, both follow from the way the rugged landscape induces fluctuations in the partitioning of energy between vibrational and configurational manifolds. A relation is derived in which the configurational heat capacity, rather than the configurational entropy of the Adam Gibbs equation, controls the temperature dependence of the relaxation times, and this gives a comparable account of the experimental observations.Comment: 21 pp., 17 fig

Adaptive walks on time-dependent fitness landscapes

The idea of adaptive walks on fitness landscapes as a means of studying evolutionary processes on large time scales is extended to fitness landscapes that are slowly changing over time. The influence of ruggedness and of the amount of static fitness contributions are investigated for model landscapes derived from Kauffman's $NK$ landscapes. Depending on the amount of static fitness contributions in the landscape, the evolutionary dynamics can be divided into a percolating and a non-percolating phase. In the percolating phase, the walker performs a random walk over the regions of the landscape with high fitness.Comment: 7 pages, 6 eps-figures, RevTeX, submitted to Phys. Rev.

On Justification, Idealization, and Discursive Purchase

Conceptions of acceptability-based moral or political justification take it that authoritative acceptability, widely conceived, constitutes, or contributes to, validity, or justification. There is no agreement as to what bar for authoritativeness such justification may employ. The paper engages the issue in relation to (i) the level of idealization that a bar for authoritativeness, ψ, imparts to a standard of acceptability-based justification, S, and (ii) the degree of discursive purchase of the discursive standing that S accords to people when it builds ψ. I argue that (i) and (ii) are interdependent: high idealization values entail low discursive purchase, while high degrees of purchase require low idealization values. I then distinguish between alethic conceptions of justification that prioritize ends that commit to high idealization values, and recognitive conceptions that favor high discursive purchase. On this basis, I argue for a moderately recognitivist constraint on idealization. To render the recognitive discursive minimum available to relevant people at the site of justification, S should set ψ low enough so that it is a genuine option for actual people to reject relevant views in ways that S recognizes as authoritative. (The Appendix applies this to a Forst-type view of reciprocity of reasons to draw out some limitations of this view.) [Draft available from author on request.

Attosecond electron thermalization by laser-driven electron recollision in atoms

Nonsequential multiple ionization of atoms in intense laser fields is initiated by a recollision between an electron, freed by tunneling, and its parent ion. Following recollision, the initial electron shares its energy with several bound electrons. We use a classical model based on rapid electron thermalization to interpret recent experiments. For neon, good agreement with the available data is obtained with an upper bound of 460 attoseconds for the thermalization time.Comment: 5 pages revtex and 4 figures (eps files

Report from the CVOT Summit 2020: new cardiovascular and renal outcomes

The 6th Cardiovascular Outcome Trial (CVOT) Summit “Cardiovascular and Renal Outcomes 2020” was the first to be held virtually on October 29–30, 2020. As in previous years, this summit served as reference meeting for in-depth discussions on the topic of recently completed and presented major outcome trials. This year, focus was placed on the outcomes of VERTIS-CV, EMPEROR-Reduced, DAPA-CKD, and FIDELIO-DKD. Trial implications for diabetes management and the impact on new treatment algorithms were highlighted for diabetologists, cardiologists, endocrinologists, nephrologists, and general practitioners. Discussion evolved from major outcome trials using SGLT-2 inhibitors for treatment and prevention of heart failure and chronic kidney disease in people with and without diabetes, to additional therapy options for chronic kidney disease with a novel mineralocorticoid receptor antagonist. Furthermore, challenges in diabetes management like COVID-19 and obesity, as well as novel treatment strategies and guidelines, were discussed. The 7th Cardiovascular Outcome Trial Summit will be held virtually on November, 18–19, 2021 (http://www.cvot.org)

Accuracy and Longevity of an Implantable Continuous Glucose Sensor in the PRECISE Study: A 180-Day, Prospective, Multicenter, Pivotal Trial

It is known that continuous glucose monitoring (CGM) systems can lower mean glucose compared with episodic self-monitoring of blood glucose. Implantable CGM systems may provide additional benefits. We studied the Eversense (Senseonics Inc.) implantable CGM sensor in 71 participants aged 18 years and older with type 1 and type 2 diabetes in a 180-day multinational, multicenter pivotal trial. Participants used the CGM system at home and in the clinic. CGM accuracy was assessed during eight in-clinic visits with the mean absolute relative difference (MARD) for venous reference glucose values >4.2 mmol/L as the primary end point. Secondary end points included Clarke Error Grid Analysis and alarm performance. The primary safety outcome was device-related serious adverse events. This trial is registered with ClinicalTrials.gov, number NCT02154126. The MARD value against reference glucose values >4.2 mmol/L was 11.1% (95% CI 10.5, 11.7). Clarke Error Grid Analysis showed 99.2% of samples in the clinically acceptable error zones A and B. Eighty-one percent of hypoglycemic events were detected by the CGM system within 30 min. No device-related serious adverse events occurred during the study. Our results indicate the safety and accuracy of this new type of implantable CGM system and support it as an alternative for transcutaneous CG

A Bayesian Approach to the Evolution of Metabolic Networks on a Phylogeny

The availability of genomes of many closely related bacteria with diverse metabolic capabilities offers the possibility of tracing metabolic evolution on a phylogeny relating the genomes to understand the evolutionary processes and constraints that affect the evolution of metabolic networks. Using simple (independent loss/gain of reactions) or complex (incorporating dependencies among reactions) stochastic models of metabolic evolution, it is possible to study how metabolic networks evolve over time. Here, we describe a model that takes the reaction neighborhood into account when modeling metabolic evolution. The model also allows estimation of the strength of the neighborhood effect during the course of evolution. We present Gibbs samplers for sampling networks at the internal node of a phylogeny and for estimating the parameters of evolution over a phylogeny without exploring the whole search space by iteratively sampling from the conditional distributions of the internal networks and parameters. The samplers are used to estimate the parameters of evolution of metabolic networks of bacteria in the genus Pseudomonas and to infer the metabolic networks of the ancestral pseudomonads. The results suggest that pathway maps that are conserved across the Pseudomonas phylogeny have a stronger neighborhood structure than those which have a variable distribution of reactions across the phylogeny, and that some Pseudomonas lineages are going through genome reduction resulting in the loss of a number of reactions from their metabolic networks

Toleration, Reasonableness, and Power

This chapter explores Rainer Forst’s justification-centric view of nondomination toleration. This view places an idea of equal respect and a corresponding requirement of reciprocal and general justification at the core of non-domination toleration. After reconstructing this view, this chapter addresses two issues. First, even if this idea of equal respect requires the limits of non-domination toleration to be drawn in a manner that is equally justifiable to all affected people, equal justifiability should not be understood in terms of Forst’s requirement of reciprocal and general acceptability. Second, for the equal justifiability of relevant constraints to ensure non-domination outcomes, discursive equality must be understood in substantive, purchase-sensitive terms. This means that a justification-centric view of non-domination toleration stands or falls with the participation value of what it regards as the standards of justification. This places reasonably contested matters of value at the heart of such views

Star Architecture as Socio-Material Assemblage

Taking inspiration from new materialism and assemblage, the chapter deals with star architects and iconic buildings as socio-material network effects that do not pre-exist action, but are enacted in practice, in the materiality of design crafting and city building. Star architects are here conceptualized as part of broader assemblages of actors and practices ‘making star architecture’ a reality, and the buildings they design are considered not just as unique and iconic objects, but dis-articulated as complex crafts mobilizing skills, technologies, materials, and forms of knowledge not necessarily ascribable to architecture. Overcoming narrow criticism focusing on the symbolic order of icons as unique creations and alienated repetitions of capitalist development, the chapter’s main aim is to widen the scope of critique by bridging culture and economy, symbolism and practicality, making star architecture available to a broad, fragmented arena of (potential) critics, unevenly equipped with critical tools and differentiated experiences