Massively Parallel Computational Chemistry with the Super Instruction Architecture and ACES4.

The task of developing high-performing parallel software must be made easier and more cost-effective in order to fully exploit existing and emerging large-scale computer systems for the advancement of science. The Super Instruction Architecture (SIA) is a parallel programming platform geared toward applications that need to manage large amounts of data stored in potentially sparse multidimensional arrays during calculations. The SIA platform was originally designed for the quantum chemistry software package ACESIII.

Initial blow fly (Diptera: Calliphoridae) colonization of cats (Felis catus) in Indiana.

Many disciplines are utilized within the field of veterinary forensic sciences, including forensic entomology. Understanding the initial colonization period by flies of forensic importance can contribute to estimating the minimum postmortem interval. There is limited data regarding the time of colonization of animals with fur, and the interpretation of this data is difficult due to the variation in animal models used.

Corrigendum: Evolution, ecology, and zoonotic transmission of betacoronaviruses: a review.

[This corrects the article DOI: 10.3389/fvets.2021.

A case of facultative ophthalmomyiasis externa due to Calliphoridae and review of the literature.

Purpose: To describe a case of bilateral facultative ophthalmomyiasis externa due to Calliphoridae in a 30-year-old male assault victim at a suburban hospital in New York and review the relevant literature.

Observations: An adult male was found to have maggot infestation of both eyes and severe secondary injury to the left cornea and ocular surface. He was treated with manual larvae removal, oral ivermectin, broad spectrum IV antibiotics, and topical antibiotics.

Corrigendum: Evolution, ecology, and zoonotic transmission of betacoronaviruses: A review.

[This corrects the article DOI: 10.3389/fvets.2021.

Review of the current and potential use of biological and molecular methods for the estimation of the postmortem interval in animals and humans.

We provide here an overview of the state of applied techniques in the estimation of the early period of the postmortem interval (PMI). The biological methods included consist of body cooling, CSF potassium, body cooling combined with CSF potassium, and tissue autolysis. For each method, we present its application in human and veterinary medicine and provide current methodology, strengths, and weaknesses, as well as target areas for improvement.

A theoretical investigation of the hydrolysis of uranium hexafluoride: the initiation mechanism and vibrational spectroscopy.

Depleted uranium hexafluoride (UF), a stockpiled byproduct of the nuclear fuel cycle, reacts readily with atmospheric humidity, but the mechanism is poorly understood. We compare several potential initiation steps at a consistent level of theory, generating underlying structures and vibrational modes using hybrid density functional theory (DFT) and computing relative energies of stationary points with double-hybrid (DH) DFT. A benchmark comparison is performed to assess the quality of DH-DFT data using reference energy differences obtained using a complete-basis-limit coupled-cluster (CC) composite method.

Evolution, Ecology, and Zoonotic Transmission of Betacoronaviruses: A Review.

Coronavirus infections have been a part of the animal kingdom for millennia. The difference emerging in the twenty-first century is that a greater number of novel coronaviruses are being discovered primarily due to more advanced technology and that a greater number can be transmitted to humans, either directly or an intermediate host. This has a range of effects from annual infections that are mild to full-blown pandemics.

Advanced concepts in electronic structure (ACES) software programs.

The advanced concepts in electronic structure (ACES) programs are products of the Bartlett research group at the University of Florida. They consist of ACES II, which is serial, and ACES III and Aces4, which are massively parallel. All three programs are publically available free of charge.

Predictive coupled-cluster isomer orderings for some SinCm (m, n ≤ 12) clusters: A pragmatic comparison between DFT and complete basis limit coupled-cluster benchmarks.

The accurate determination of the preferred Si12C12 isomer is important to guide experimental efforts directed towards synthesizing SiC nano-wires and related polymer structures which are anticipated to be highly efficient exciton materials for the opto-electronic devices. In order to definitively identify preferred isomeric structures for silicon carbon nano-clusters, highly accurate geometries, energies, and harmonic zero point energies have been computed using coupled-cluster theory with systematic extrapolation to the complete basis limit for set of silicon carbon clusters ranging in size from SiC3 to Si12C12. It is found that post-MBPT(2) correlation energy plays a significant role in obtaining converged relative isomer energies, suggesting that predictions using low rung density functional methods will not have adequate accuracy.

Approximating electronically excited states with equation-of-motion linear coupled-cluster theory.

A new perturbative approach to canonical equation-of-motion coupled-cluster theory is presented using coupled-cluster perturbation theory. A second-order Møller-Plesset partitioning of the Hamiltonian is used to obtain the well known equation-of-motion many-body perturbation theory equations and two new equation-of-motion methods based on the linear coupled-cluster doubles and linear coupled-cluster singles and doubles wavefunctions. These new methods are benchmarked against very accurate theoretical and experimental spectra from 25 small organic molecules.

Tuning ultracold chemical reactions via Rydberg-dressed interactions.

We show that ultracold chemical reactions with an activation barrier can be tuned using Rydberg-dressed interactions. Scattering in the ultracold regime is sensitive to long-range interactions, especially when weakly bound (or quasibound) states exist near the collision threshold. We investigate how, by Rydberg dressing a reactant, one enhances its polarizability and modifies the long-range van der Waals collision complex, which can alter chemical reaction rates by shifting the position of near-threshold bound states.

Correlation correction to configuration interaction singles from coupled cluster perturbation theory.

A new state specific correlation correction to configuration interaction singles (CIS) excitation energies is presented using coupled cluster perturbation theory (CCPT). General expressions for CIS-CCPT are derived and expanded explicitly to first-order in the wavefunction and second-order in the energy. By virtue of the nature of CCPT this method is a priori size extensive and incorporates infinite-order effects into the wavefunction.

At what chain length do unbranched alkanes prefer folded conformations?

Short unbranched alkanes are known to prefer linear conformations, whereas long unbranched alkanes are folded. It is not known with certainty at what chain length the linear conformation is no longer the global minimum. To clarify this point, we use ab initio and density functional methods to compute the relative energies of the linear and hairpin alkane conformers for increasing chain lengths.

Controllable binding of polar molecules and metastability of one-dimensional gases with attractive dipole forces.

We explore one-dimensional samples of ultracold polar molecules with attractive dipole-dipole interactions and show the existence of a repulsive barrier caused by a strong quadrupole interaction between molecules. This barrier can stabilize a gas of ultracold KRb molecules and even lead to long-range wells supporting bound states between the molecules. The properties of these wells can be controlled by external electric fields, allowing the formation of long polymerlike chains of KRb and studies of quantum phase transitions by varying the effective interaction between molecules.

Structure, energetics, and reactions of alkali tetramers.

Electronic structure calculations have been carried out for all possible alkali tetramers that can be formed from X(2) + X(2) → X(2)X(2), X(2) + Y(2) → X(2)Y(2), and XY + XY → X(2)Y(2) alkali dimer association reactions. Vibrationally stable rhombic (D(2h)) and planar (C(s)) structures are found for all possible tetramers formed from the alkali metals, Li to Cs. All tetramer formation reactions (from ground state singlet homonuclear or heteronuclear dimers) are found to be exothermic with binding energies ranging from 6282 cm(-1) for Li(2)Li(2) to 1985 cm(-1) for Cs(2)Cs(2).

Long-range interactions between like homonuclear alkali metal diatoms.

Long-range electrostatic and van der Waals coefficients up to terms of order R(-8) have been evaluated by the sum over states method using ab initio and time-dependent density functional theory. We employ several widely used density functionals and systematically investigate the convergence of the calculated results with basis set size. Static electric moments and polarizabilities up to octopole order are also calculated.

Long range intermolecular interactions between the alkali diatomics Na(2), K(2), and NaK.

Long range interactions between the ground state alkali diatomics Na(2)-Na(2), K(2)-K(2), Na(2)-K(2), and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies.

The door-to-balloon alliance for quality: who joins national collaborative efforts and why?

Background: The Door-to-Balloon (D2B) Alliance is a collaborative effort of more than 900 hospitals aimed at improving D2B times for ST-segment elevation myocardial infarction. Although such collaborative efforts are increasingly used to promote improvement, little is known about the types of health care organizations that enroll and their motivations to participate.

Methods: To examine the types of hospitals enrolled and reasons for enrollment, a cross-sectional study was conducted of 915 D2B Alliance hospitals and 654 hospitals that did not join the D2B Alliance.

Contemporary evidence: baseline data from the D2B Alliance.

Background: Less than half of U.S. hospitals meet guidelines for prompt treatment of ST-segment elevation myocardial infarction (STEMI).

A campaign to improve the timeliness of primary percutaneous coronary intervention: Door-to-Balloon: An Alliance for Quality.

Objectives: We sought to describe the rationale and methods for Door-to-Balloon (D2B): An Alliance for Quality, an international effort organized by the American College of Cardiology in partnership with the American Heart Association and 37 other organizations to rapidly translate research about how best to achieve outstanding D2B times for patients with ST-segment elevation myocardial infarction (STEMI) into practice.

Background: The D2B time, the time between hospital arrival and primary percutaneous coronary intervention for patients with STEMI, is strongly associated with the likelihood of survival, yet the majority of patients are not treated within the guideline-recommended time of View Article and Find Full Text PDF

Interdisciplinary workshop yields new entomological data for forensic sciences: Chrysomya rufifacies (Diptera: Calliphoridae) established in North Carolina.

ABSTRACT Workshops are used for educating law enforcement personnel on the application of entomological, anthropological, and botanical techniques to gather forensically important information from a body recovery site. From 8 to 11 June 2004, such a workshop was conducted in the metropolitan area of Charlotte, NC, by the American Academy of Applied Forensics at Central Piedmont Community College. For this workshop, three pig carcasses weighing individually between 40 and 60 kg were placed in the field 4 June, whereas three pigs similar in size were placed in the field 7 June.