124 research outputs found
Shape and energy consistent pseudopotentials for correlated electron systems
A method is developed for generating pseudopotentials for use in correlated-electron calculations. The paradigms of shape and energy consistency are combined and defined in terms of correlated-electron wave-functions. The resulting energy consistent correlated electron pseudopotentials (eCEPPs) are constructed for H, Li–F, Sc–Fe, and Cu. Their accuracy is quantified by comparing the relaxed molecular geometries and dissociation energies which they provide with all electron results, with all quantities evaluated using coupled cluster singles, doubles, and triples calculations. Errors inherent in the pseudopotentials are also compared with those arising from a number of approximations commonly used with pseudopotentials. The eCEPPs provide a significant improvement in optimised geometries and dissociation energies for small molecules, with errors for the latter being an order-of-magnitude smaller than for Hartree-Fock-based pseudopotentials available in the literature. Gaussian basis sets are optimised for use with these pseudopotentials.R.J.N. and J.R.T. acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC) of the U.K. (No. EP/J017639/1)
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Energetics of H clusters from density functional and coupled cluster theories
We use coupled-cluster quantum chemical methods to calculate the energetics of molecular clusters cut out of periodic molecular hydrogen structures that model observed phases of solid hydrogen. The hydrogen structures are obtained from Kohn-Sham density functional theory (DFT) calculations at pressures of 150, 250, and 350 GPa, which are within the pressure range in which phases II, III, and IV are found to be stable. The calculated deviations in the DFT energies from the coupled-cluster data are reported for different functionals, and optimized functionals are generated which provide reduced errors. We give recommendations for semilocal and hybrid density functionals that are expected to provide an accurate description of hydrogen at high pressures.The authors acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC) of the U.K. [EP/J017639/1]. Computational resources were provided by the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk)
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Preliminary site report for the 2005 ICDP-USGS deep corehole in the Chesapeake Bay impact crater
First report for the ICDP-USGS 1.7-km-deep corehole drilled into the central part of the Chesapeake Bay impact crater during 2005
Prospectus, May 7, 1981
SPEECH TEAM 11TH RANKED; National Forensics Top 20; C of C V-P, Neils predicts downtown area will change; Overcast and Snyder receive award; Co-Editors named for 1981-82; Barnes looks back on his Parkland experiences; Letters to the Editor: Student criticizes review; Classifieds; Our mistake! Stugo candidate got platform in on time; Convocations Wants You!!; Now is the time to get married; More letters to the Editor: New Stugo senator, Jackson appreciates support; Schumacher\u27s final notes...; Trail, Hillary win in close Stugo election last week; Trail expresses gratitude for the voters; Be kind to animals ; Japan King of bicycle road; Motocross bikes good for kids; Rogers, Gayle at Assembly Hall May 13.; Off Broadway: Dynamic, Aggressive; Gayle not living under Lorett\u27s shadow now!; Piloting not as easy as you may think!; Drug problem is going to get worse. ; Art Thesis Exhibit disappointing; Latin may be on its way back; Parkland secretaries enjoy the good life; Model Rockets popular; RWS\u27S help each other; PC offers one-day driving course; Ramblin\u27: Alender\u27s rambles are over; Rundgren just changing with the times; Do you want hard rock...?; Frazier, Turpin part of Senior May Fest; Here\u27s the 1981 Prospectus staff; CIRS has the info on day care; Did You Know That...Some Superstitions; \u27Recent rains still not enough\u27: Burwash; Barkstall appalled by Atlanta slayings: Urban League director says blacks are still discriminated against; Are we running out of natural resources?; Get out your horses for PC\u27s Horse Show; Parkland Happenings: Spring concerts feature Irving Berlin; Awards Banquet a success!; Winning Intellectual Freedom Essay; A child\u27s world is important throughout all stages; Dental classes named for \u2781-82; Final Examinations -- Spring, 1981; Cobras bow to Lake Land; Patrick to Tennessee; Softball team beats Danville; ...beat Lincoln Land three; Letter to the Sports Editor: Student upset; Walder wins final Fast Freddy; scoreboard; Baseballhttps://spark.parkland.edu/prospectus_1981/1017/thumbnail.jp
Extracorporeal Membrane Oxygenation for Acute Pediatric Respiratory Failure
This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.The use of extracorporeal membrane oxygenation (ECMO) to support children with acute respiratory failure has steadily increased over the past several decades, with major advancements having been made in the care of these children. There are, however, many controversies regarding indications for initiating ECMO in this setting and the appropriate management strategies thereafter. Broad indications for ECMO include hypoxia, hypercarbia, and severe air leak syndrome, with hypoxia being the most common. There are many disease-specific considerations when evaluating children for ECMO, but there are currently very few, if any, absolute contraindications. Venovenous rather than veno-arterial ECMO cannulation is the preferred configuration for ECMO support of acute respiratory failure due to its superior side-effect profile. The approach to lung management on ECMO is variable and should be individualized to the patient, with the main goal of reducing the risk of VILI. ECMO is a relatively rare intervention, and there are likely a minimum number of cases per year at a given center to maintain competency. Patients who have prolonged ECMO runs (i.e., greater than 21 days) are less likely to survive, though no absolute duration of ECMO that would mandate withdrawal of ECMO support can be currently recommended
A Social Identity Approach to Sport Psychology: Principles, Practice, and Prospects.
Drawing on social identity theory and self-categorization theory, we outline an approach to sport psychology that understands groups not simply as features of sporting contexts but rather as elements that can be, and often are, incorporated into a person's sense of self and, through this, become powerful determinants of their sport-related behavior. The underpinnings of this social identity approach are outlined, and four key lessons for sport that are indicative of the analytical and practical power of the approach are presented. These suggest that social identity is the basis for sports group (1) behavior, (2) formation and development, (3) support and stress appraisal, and (4) leadership. Building on recent developments within sport science, we outline an agenda for future research by identifying a range of topics to which the social identity approach could fruitfully contribute
Natural History of Tuberculosis: Duration and Fatality of Untreated Pulmonary Tuberculosis in HIV Negative Patients: A Systematic Review
Background The prognosis, specifically the case fatality and duration, of untreated tuberculosis is important as many patients are not correctly diagnosed and therefore receive inadequate or no treatment. Furthermore, duration and case fatality of tuberculosis are key parameters in interpreting epidemiological data. Methodology and Principal Findings To estimate the duration and case fatality of untreated pulmonary tuberculosis in HIV negative patients we reviewed studies from the pre-chemotherapy era. Untreated smear-positive tuberculosis among HIV negative individuals has a 10-year case fatality variously reported between 53% and 86%, with a weighted mean of 70%. Ten-year case fatality of culture-positive smear-negative tuberculosis was nowhere reported directly but can be indirectly estimated to be approximately 20%. The duration of tuberculosis from onset to cure or death is approximately 3 years and appears to be similar for smear-positive and smear-negative tuberculosis. Conclusions Current models of untreated tuberculosis that assume a total duration of 2 years until self-cure or death underestimate the duration of disease by about one year, but their case fatality estimates of 70% for smear-positive and 20% for culture-positive smear-negative tuberculosis appear to be satisfactory
GW190412: Observation of a Binary-Black-Hole Coalescence with Asymmetric Masses
We report the observation of gravitational waves from a binary-black-hole coalescence during the first two weeks of LIGO’s and Virgo’s third observing run. The signal was recorded on April 12, 2019 at 05∶30∶44 UTC with a network signal-to-noise ratio of 19. The binary is different from observations during the first two observing runs most notably due to its asymmetric masses: a ∼30 M_⊙ black hole merged with a ∼8 M_⊙ black hole companion. The more massive black hole rotated with a dimensionless spin magnitude between 0.22 and 0.60 (90% probability). Asymmetric systems are predicted to emit gravitational waves with stronger contributions from higher multipoles, and indeed we find strong evidence for gravitational radiation beyond the leading quadrupolar order in the observed signal. A suite of tests performed on GW190412 indicates consistency with Einstein’s general theory of relativity. While the mass ratio of this system differs from all previous detections, we show that it is consistent with the population model of stellar binary black holes inferred from the first two observing runs
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