A Numerical Approach to the Accurate Calculation of Atomic and Molecular Properties

An attempt is made to demonstrate that simple numerical methods can be used to advantage in the accurate calculation of atomic and molecular properties. In the early part of the thesis finite-difference techniques are employed in conjunction with conventional variational methods to calculate accurately the correlation energies of small atoms within a variety of perturbation schemes. Of particular interest is a thorough investigation of Hartree-Fock perturbation theory through third order for the Be isoeleotronic sequence Li- -- Ne6+ with about a 90% recovery of Ecorr. Numerical methods are also used to examine the efficacy of the single-centre approach to the calculation of the electronic structures of simple molecules in their ground and excited states, the high accuracy of the computational scheme employed allowing some insight into the frequently observed slow convergence of the one-centre method. The efficiency of numerical techniques in the determination of atomic and molecular properties is further shown by studies on the non-empirical evaluation of atomic polarisabilities (static and dynamic) and of interatomic dispersion forces. Notably a new method of computing Van der Waals coefficients of considerable elegance and economy is presented. In the final section of the work the numerical computational techniques developed in non-empirical calculations of pair correlation energies, polarisabilities, dispersion coefficients in small systems are applied to much larger atoms within a model potential framework. All of the above properties are determined for a wide variety of systems with however the alkali metals and their anions being the subject of the most comprehensive treatment

Developing numerical libraries in Java

The rapid and widespread adoption of Java has created a demand for reliable and reusable mathematical software components to support the growing number of compute-intensive applications now under development, particularly in science and engineering. In this paper we address practical issues of the Java language and environment which have an effect on numerical library design and development. Benchmarks which illustrate the current levels of performance of key numerical kernels on a variety of Java platforms are presented. Finally, a strategy for the development of a fundamental numerical toolkit for Java is proposed and its current status is described.Comment: 11 pages. Revised version of paper presented to the 1998 ACM Conference on Java for High Performance Network Computing. To appear in Concurrency: Practice and Experienc

Work and Family Variables as Related to Paternal Engagement, Responsibility, and Accessibility in Dual-Earner Couples with Young Children

Fathers and mothers (N = 75 dual-earner couples) of preschool-aged children completed questionnaires that examined work and family variables as related to paternal involvement in three areas: engagement (i.e., directly interacting with the child), responsibility (i.e., scheduling activities and being accountable for the child\u27s well-being), and accessibility (i.e., being available to the child but not in direct interaction). Fathers\u27 reports of responsibility and accessibility were significantly predicted by structural variables and beliefs; however, fathers\u27 reports of engagement were not predicted by work and family variables. Mothers\u27 reports of work and family variables did not predict their reports of father involvement. These findings suggest that for fathers of young children, parental involvement appears mainly self-determined

N fertilizer and harvest impacts on bioenergy crop contributions to SOC

Below ground root biomass is infrequently measured and simply represented in models that predict landscape level changes to soil carbon stocks and greenhouse gas balances. Yet, crop-specific responses to N fertilizer and harvest treatments are known to impact both plant allocation and tissue chemistry, potentially altering decomposition rates and the direction and magnitude of soil C stock changes and greenhouse gas fluxes. We examined switchgrass (Panicum virgatum L.) and corn (Zea mays L.,) yields, below ground root biomass, C, N and soil particulate organic matter-C (POM-C) in a 9-year rain fed study of N fertilizer rate (0, 60, 120 and 180 kg N ha-1) and harvest management near Mead, NE, USA. Switchgrass was harvested with one pass in either August or postfrost, and for no-till (NT) corn, either 50% or no stover was removed. Switchgrass had greater below ground root biomass C and N (6.39, 0.10 Mg ha-1) throughout the soil profile compared to NT-corn (1.30, 0.06 Mg ha-1) and a higher below ground root biomass C:N ratio, indicating greater recalcitrant below ground root biomass C input beneath switchgrass. There was little difference between the two crops in soil POM-C indicating substantially slower decomposition and incorporation into SOC under switchgrass, despite much greater root C. The highest N rate decreased POM-C under both NT-corn and switchgrass, indicating faster decomposition rates with added fertilizer. Residue removal reduced corn below ground root biomass C by 37% and N by 48% and subsequently reduced POM-C by 22% compared to no-residue removal. Developing productive bioenergy systems that also conserve the soil resource will require balancing fertilization that maximizes above ground productivity but potentially reduces SOC sequestration by reducing below ground root biomass and increasing root and soil C decomposition

N fertilizer and harvest impacts on bioenergy crop contributions to SOC

Below ground root biomass is infrequently measured and simply represented in models that predict landscape level changes to soil carbon stocks and greenhouse gas balances. Yet, crop-specific responses to N fertilizer and harvest treatments are known to impact both plant allocation and tissue chemistry, potentially altering decomposition rates and the direction and magnitude of soil C stock changes and greenhouse gas fluxes. We examined switchgrass (Panicum virgatum L.) and corn (Zea mays L.,) yields, below ground root biomass, C, N and soil particulate organic matter-C (POM-C) in a 9-year rain fed study of N fertilizer rate (0, 60, 120 and 180 kg N ha-1) and harvest management near Mead, NE, USA. Switchgrass was harvested with one pass in either August or postfrost, and for no-till (NT) corn, either 50% or no stover was removed. Switchgrass had greater below ground root biomass C and N (6.39, 0.10 Mg ha-1) throughout the soil profile compared to NT-corn (1.30, 0.06 Mg ha-1) and a higher below ground root biomass C:N ratio, indicating greater recalcitrant below ground root biomass C input beneath switchgrass. There was little difference between the two crops in soil POM-C indicating substantially slower decomposition and incorporation into SOC under switchgrass, despite much greater root C. The highest N rate decreased POM-C under both NT-corn and switchgrass, indicating faster decomposition rates with added fertilizer. Residue removal reduced corn below ground root biomass C by 37% and N by 48% and subsequently reduced POM-C by 22% compared to no-residue removal. Developing productive bioenergy systems that also conserve the soil resource will require balancing fertilization that maximizes above ground productivity but potentially reduces SOC sequestration by reducing below ground root biomass and increasing root and soil C decomposition

A comprehensive multidisciplinary care pathway for hip fractures better outcome than usual care?

Introduction: Hip fracture surgery is among the most performed surgical procedures in elderly patients. Mortality rates are high, however, and patients often fail to live independently following a hip fracture. To improve outcome, multidisciplinary care pathways have been initiated, but longer-term results are lacking. Aim of this study was to compare functional outcome and living situation six months after hip fracture treatment with and without a care pathway. Patients and methods: A multicentre prospective controlled trial was conducted with three hospitals: in one hospital patients were treated with a care pathway, in the other hospitals patients received usual care. All patients aged >= 60 years witha hipfracture were asked to participate. Besides basic characteristics, health-related quality of life (EQ-5D) and performance scores of activities of daily living (Katz Index and Lawton IADL) were assessed. Differences in scores were analysed using linear regression. Propensity score adjustment was used to correct for differences between the care pathway and the usual care group. Missing data were imputed. Results: No differences in rate of return to prefracture ADL level were found between patients in the care pathway group and the usual care group. The percentage of participants in the same situation as before the fracture was the same in both treatment groups (81%). There were no significant differences in quality of life, activities of daily living or mortality (15% vs 10%, p = 0.17), but hospital stay in the care pathway group was significantly shorter (median 7 vs 10 days). Discussion: Treatment of elderly patients with a hip fracture is commonly organised in care pathways. Although short-term advantages are reported, positive effects on longer-term functional results could not be proven in our study. This study confirmed a shorter hospital stay in the care pathway group, which potentially may lead to a reduction in costs. Conclusions: Functional outcome and living situation six months after a hip fracture is the same for patients treated with or without a care pathway. (C) 2021 The Author(s). Published by Elsevier Ltd

Diagnosing Autism Spectrum Disorder in community settings using the development and well-being assessment: validation in a UK population-based twin sample

Background: Increasing numbers of people are being referred for assessment for autism spectrum disorder (ASD). The NICE (UK) and the American Academy of Pediatrics recommend gathering a developmental history using a tool that operationalises ICD/DSM criteria. However the best-established diagnostic interview instruments are time-consuming, costly and rarely used outside national specialist centres. What is needed is a brief, cost-effective measure validated in community settings. We tested the Development and Well-Being Assessment (DAWBA) for diagnosing ASD in a sample of children/adolescents representative of those presenting in community mental health settings. Methods: A general population sample of twins (TEDS) was screened and 276 adolescents were selected as at low (CAST score<12; n=164) or high risk for ASD (CAST score≥15 and/or parent reported that ASD suspected/previously diagnosed; n=112). Parents completed the ASD module of the DAWBA interview by telephone or online. Families were visited at home: the ADI-R and ADOS were completed to allow a best-estimate diagnosis of ASD to be made. Results: DAWBA ASD symptom scores correlated highly with ADI-R algorithm scores (rho=.82, p<.001). Good sensitivity (0.88) and specificity (0.85) were achieved using DAWBA computerised algorithms. Clinician review of responses to DAWBA questions minimally changed sensitivity (0.86) and specificity (0.87). Positive (0.82-0.95) and negative (0.90) predictive values were high. Eighty-six percent of children were correctly classified. Performance was improved by using it in conjunction with the ADOS. Conclusions: The DAWBA is a brief structured interview that showed good sensitivity and specificity in this general population sample. It requires little training, is easy to administer (online or by interview), and diagnosis is aided by an algorithm. It holds promise as a tool for assisting with assessment in community settings and may help services implement the recommendations made by NICE and the American Academy of Pediatrics regarding diagnosis of young people on the autism spectru

Counting the Acid Sites in a Commercial ZSM-5 Zeolite Catalyst

This work was funded by Johnson Matthey plc. through the provision of industrial CASE studentships in partnership with the EPSRC (AZ (EP/N509176/1), APH (EP/P510506/1)). Experiments at the ISIS Neutron and Muon Source were made possible by beam time allocations from the Science and Technologies Facilities Council.45,46 Resources and support were provided by the UK Catalysis Hub via membership of the UK Catalysis Hub consortium and funded by EPSRC grants EP/R026815/1 and EP/R026939/1Peer reviewedPublisher PD

Twelve Years of Stover Removal Increases Soil Erosion Potential without Impacting Yield

Corn (Zea mays L.) stover (non-grain aboveground biomass) in the US Corn Belt is used increasingly for livestock grazing and co-feed and for cellulosic bioenergy production. Continuous stover removal, however, could alter long-term agricultural productivity by affecting soil organic C (SOC) and soil physical properties, indicators of soil fertility and erosion potential. In this study, we showed that 12 consecutive yr of 55% stover removal did not affect mean grain yields at any N fertilizer rate (4.5, 6.3, and 6.0 Mg ha−1 for 60, 120, and 180 kg N ha−1 yr−1, respectively) in a marginally productive, rainfed continuous corn system under no-till (NT). Although SOC increased in the top 30 cm of all soils since 1998 (0.54–0.79 Mg C ha−1 yr−1), stover removal tended to limit SOC gains compared with no removal. Near-surface soils (0–5-cm depth) were more sensitive to stover removal and showed a 41% decrease in particulate organic matter stocks, smaller mean weight diameter of dry soil aggregates, and lower abundance of water-stable soil aggregates compared with soils with no stover removal. Increasing N fertilizer rate mitigated losses in total water-stable aggregates in near-surface soils related to stover removal. Collectively, however, our results indicated soil structure losses in surface soils due to lower C inputs. Despite no effect on crop yields and overall SOC gains with time using NT management, annually removing stover for 12 yr resulted in a higher risk of wind and water erosion at this NT continuous corn site in the western Corn Belt