5,6-dihydroxyindole-2-carboxylic acid (DHICA): a First Principles Density-Functional Study

We report first principles density functional calculations for 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and several reduced forms. DHICA and 5,6-dihydroxyindole (DHI) are believed to be the basic building blocks of the eumelanins. Our results show that carboxylation has a significant effect on the physical properties of the molecules. In particular, the relative stabilities and the HOMO-LUMO gaps (calculated with the $\Delta$SCF method) of the various redox forms are strongly affected. We predict that, in contrast to DHI, the density of unpaired electrons, and hence the ESR signal, in DHICA is negligibly small.Comment: 5 pages, 2 figure

Electronic correlations in organometallic complexes

We investigate an effective model for organometallic complexes (with potential uses in optoelectronic devices) via both exact diagonalisation and the configuration interaction singles (CIS) approximation. This model captures a number of important features of organometallic complexes, notably the sensitivity of the radiative decay rate to small chemical changes. We find that for large parameter ranges the CIS approximation accurately reproduces the low energy excitations and hence the photophysical properties of the exact solution. This suggests that electronic correlations do \emph{not} play an important role in these complexes. This explains why time-dependent density functional theory works surprisingly well in these complexes.Comment: 11 pages, 6 figure

The case for prioritizing implementation strategy fidelity measurement: Benefits and challenges

Implementation strategies are systematic approaches to improve the uptake and sustainability of evidence-based interventions. They frequently focus on changing provider behavior through the provision of interventions such as training, coaching, and audit-and-feedback. Implementation strategies often impact intermediate behavioral outcomes like provider guideline adherence, in turn improving patient outcomes. Fidelity of implementation strategy delivery is defined as the extent to which an implementation strategy is carried out as it was designed. Implementation strategy fidelity measurement is under-developed and under-reported, with the quality of reporting decreasing over time. Benefits of fidelity measurement include the exploration of the extent to which observed effects are moderated by fidelity, and critical information about Type-III research errors, or the likelihood that null findings result from implementation strategy fidelity failure. Reviews of implementation strategy efficacy often report wide variation across studies, commonly calling for increased implementation strategy fidelity measurement to help explain variations. Despite the methodological benefits of rigorous fidelity measurement, implementation researchers face multi-level challenges and complexities. Challenges include the measurement of a complex variable, multiple data collection modalities with varying precision and costs, and the need for fidelity measurement to change in-step with adaptations. In this position paper, we weigh these costs and benefits and ultimately contend that implementation strategy fidelity measurement and reporting should be improved in trials of implementation strategies. We offer pragmatic solutions for researchers to make immediate improvements like the use of mixed methods or innovative data collection and analysis techniques, the inclusion of implementation strategy fidelity assessment in reporting guidelines, and the staged development of fidelity tools across the evolution of an implementation strategy. We also call for additional research into the barriers and facilitators of implementation strategy fidelity measurement to further clarify the best path forward

Spin Fluctuations and the Magnetic Phase Diagram of ZrZn2

The magnetic properties of the weak itinerant ferromagnet ZrZn_2 are analyzed using Landau theory based on a comparison of density functional calculations and experimental data as a function of field and pressure. We find that the magnetic properties are strongly affected by the nearby quantum critical point, even at zero pressure; LDA calculations neglecting quantum critical spin fluctuations overestimate the magnetization by a factor of approximately three. Using renormalized Landau theory, we extract pressure dependence of the fluctuation amplitude. It appears that a simple scaling based on the fluctuation-dissipation theorem provides a good description of this pressure dependence.Comment: 4 revtex page

Is there H2O stacking disordered ice I in the Solar System?

Water ice exists in large quantities across the Solar System, and it is involved in a wide range of atmospheric and geological processes. Here we focus on the question if stacking disordered ice I (ice Isd) is present in the Solar System. The conditions required to form ice Isd are described and we argue that previous descriptions of ‘cubic ice’ (ice Ic) in the literature may in fact have been concerned with ice Isd. In contrast to the stable hexagonal ice I (ice Ih) and ice Ic, ice Isd is a highly complex material that encompasses a wide range of possible stacking regimes and structures. The most fundamental quantity to describe a given ice Isd sample is its cubicity which reflects the fraction of cubic stacking. Following an introduction into the characterisation techniques used to identify and characterise ice Isd, we discuss the various environments in the Solar System where ice Isd may exist and the relevance its existence may have. This includes the atmospheres of the inner planets, various icy moons as well as comets and other icy objects in the far reaches of the Solar System. The details of the stacking disorder may contain information about the formation and thermal history of ice Isd samples. This offers the exciting prospect of using ice Isd as a marker material for atmospheric and geological processes. The crystallographic space group of ice Isd allows polar structures which could be an important factor for the accretion of ice particles in space. We conclude that ice Isd should exist at several locations in the Solar System and in potentially large quantities. The definitive identification of ice Isd in a natural environment is a next major milestone in our understanding of the importance of water ice across the Solar System

The impact of basic vs. enhanced Go NAPSACC on child care centers' healthy eating and physical activity practices: Protocol for a type 3 hybrid effectiveness-implementation cluster-randomized trial

Background: To prevent childhood obesity and promote healthy development, health authorities recommend that child care programs use the evidence-based practices that foster healthy eating and physical habits in children. Go NAPSACC is an intervention shown to improve use of these recommended practices, but it is known to encounter barriers that limit its impact and widespread use. Methods: This study will use a type 3 hybrid effectiveness-implementation cluster-randomized trial to compare effectiveness and implementation outcomes achieved from Go NAPSACC delivered with a basic or enhanced implementation approach. Participants will include approximately 25 coaches from Child Care Aware of Kentucky (serving four geographic regions), 97 child care centers with a director and teacher from each and two cross-sectional samples of 485 3-4-year-old children (one recruitment at baseline, another at follow-up). Coaches will be randomly assigned to deliver Go NAPSACC using either the basic or enhanced implementation approach. "Basic Go NAPSACC" represents the traditional way of delivering Go NAPSACC. "Enhanced Go NAPSACC" incorporates preparatory and support activities before and during their Go NAPSACC work, which are guided by the Quality Implementation Framework and the Consolidated Framework for Implementation Research. Data will be collected primarily at baseline and post-intervention, with select measures continuing through 6, 12, and 24 months post-intervention. Guided largely by RE-AIM, outcomes will assess change in centers' use of evidence-based nutrition and physical activity practices (primary, measured via observation); centers' adoption, implementation, and maintenance of the Go NAPSACC program (assessed via website use); center directors', teachers', and coaches' perceptions of contextual factors (assessed via self-report surveys); children's eating and physical activity behaviors at child care (measured via observation and accelerometers); and cost-effectiveness (assessed via logs and expense tracking). The hypotheses anticipate that "Enhanced Go NAPSACC" will have greater effects than "Basic Go NAPSACC." Discussion: This study incorporates many lessons gleaned from the growing implementation science field, but also offers opportunities to address the field's research priorities, including applying a systematic method to tailor implementation strategies, examining the processes and mechanisms through which implementation strategies produce their effects, and conducting an economic evaluation of implementation strategies. Trial Registration: ClinicalTrials.gov, NCT03938103, Registered April 8, 201

The Dependence of the Superconducting Transition Temperature of Organic Molecular Crystals on Intrinsically Non-Magnetic Disorder: a Signature of either Unconventional Superconductivity or Novel Local Magnetic Moment Formation

We give a theoretical analysis of published experimental studies of the effects of impurities and disorder on the superconducting transition temperature, T_c, of the organic molecular crystals kappa-ET_2X and beta-ET_2X (where ET is bis(ethylenedithio)tetrathiafulvalene and X is an anion eg I_3). The Abrikosov-Gorkov (AG) formula describes the suppression of T_c both by magnetic impurities in singlet superconductors, including s-wave superconductors and by non-magnetic impurities in a non-s-wave superconductor. We show that various sources of disorder lead to the suppression of T_c as described by the AG formula. This is confirmed by the excellent fit to the data, the fact that these materials are in the clean limit and the excellent agreement between the value of the interlayer hopping integral, t_perp, calculated from this fit and the value of t_perp found from angular-dependant magnetoresistance and quantum oscillation experiments. If the disorder is, as seems most likely, non-magnetic then the pairing state cannot be s-wave. We show that the cooling rate dependence of the magnetisation is inconsistent with paramagnetic impurities. Triplet pairing is ruled out by several experiments. If the disorder is non-magnetic then this implies that l>=2, in which case Occam's razor suggests that d-wave pairing is realised. Given the proximity of these materials to an antiferromagnetic Mott transition, it is possible that the disorder leads to the formation of local magnetic moments via some novel mechanism. Thus we conclude that either kappa-ET_2X and beta-ET_2X are d-wave superconductors or else they display a novel mechanism for the formation of localised moments. We suggest systematic experiments to differentiate between these scenarios.Comment: 18 pages, 5 figure

A Galaxy-scale Fountain of Cold Molecular Gas Pumped by a Black Hole

We present Atacama Large Millimeter/submillimeter Array and Multi-Unit Spectroscopic Explorer observations of the brightest cluster galaxy in Abell 2597, a nearby (z = 0.0821) cool core cluster of galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxy's core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning "fountain," wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scales

A reassessment of Kelmayisaurus petrolicus, a large theropod dinosaur from the Early Cretaceous of China

The Early Cretaceous fossil record of large−bodied theropods from Asia is poor, hindering comparison of Asian predatory dinosaur faunas with those from other continents. One of the few large Asian theropod specimens from this interval is a partial skull (maxilla and dentary) from the Lianmugin Formation (?Valanginian–Albian), the holotype of Kelmayisaurus petrolicus. Most authors have either considered this specimen as an indeterminate basal tetanuran or a nomen dubium. Weredescribe K. petrolicus and note that it possesses a single autapomorphy (a deep accessory groove on the lateral surface of the anterior dentary), as well as a unique combination of characters that differentiates it from other theropods, affirming its validity. A phylogenetic analysis recovers K. petrolicus as a basal carcharodontosaurid, which is supported by various features: very deep interdental plates (a carcharodontosaurid synapomorphy), fused interdental plates (present in carchardontosaurids and a limited number of other theropods), and the absence of diagnostic features of other clades of large−bodied theropods such as abelisaurids, megalosauroids, and coelurosaurs. As such, Kelmayisaurus is the second known carcharodontosaurid from Asia, and further evidence that this clade represented a global radiation of large−bodied predators during the Early–mid Cretaceous

Comparing a standard and tailored approach to scaling up an evidence-based intervention for antiretroviral therapy for people who inject drugs in Vietnam: Study protocol for a cluster randomized hybrid type III trial

Background: People who inject drugs (PWID) bear a disproportionate burden of HIV infection and experience poor outcomes. A randomized trial demonstrated the efficacy of an integrated System Navigation and Psychosocial Counseling (SNaP) intervention in improving HIV outcomes, including antiretroviral therapy (ART) and medications for opioid use disorder (MOUD) uptake, viral suppression, and mortality. There is limited evidence about how to effectively scale such intervention. This protocol presents a hybrid type III effectiveness-implementation trial comparing two approaches for scaling-up SNaP. We will evaluate the effectiveness of SNaP implementation approaches as well as cost and the characteristics of HIV testing sites achieving successful or unsuccessful implementation of SNaP in Vietnam. Methods: Design: In this cluster randomized controlled trial, two approaches to scaling-up SNaP for PWID in Vietnam will be compared. HIV testing sites (n = 42) were randomized 1:1 to the standard approach or the tailored approach. Intervention mapping was used to develop implementation strategies for both arms. The standard arm will receive a uniform package of these strategies, while implementation strategies for the tailored arm will be designed to address site-specific needs. Participants: HIV-positive PWID participants (n = 6200) will be recruited for medical record assessment at baseline; of those, 1500 will be enrolled for detailed assessments at baseline, 12, and 24 months. Site directors and staff at each of the 42 HIV testing sites will complete surveys at baseline, 12, and 24 months. Outcomes: Implementation outcomes (fidelity, penetration, acceptability) and effectiveness outcomes (ART, MOUD uptake, viral suppression) will be compared between the arms. To measure incremental costs, we will conduct an empirical costing study of each arm and the actual process of implementation from a societal perspective. Qualitative and quantitative site-level data will be used to explore key characteristics of HIV testing sites that successfully or unsuccessfully implement the intervention for each arm. Discussion: Scaling up evidence-based interventions poses substantial challenges. The proposed trial contributes to the field of implementation science by applying a systematic approach to designing and tailoring implementation strategies, conducting a rigorous comparison of two promising implementation approaches, and assessing their incremental costs. Our study will provide critical guidance to Ministries of Health worldwide regarding the most effective, cost-efficient approach to SNaP implementation. Trial registration: NCT03952520 on Clinialtrials.gov. Registered 16 May 2019