236 research outputs found

    Fractionation of nitrogen isotopes by animals: a further complication to the use of variations in the natural abundance of ¹⁵N for tracer studies

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    A study of the fractionation of nitrogen isotopes in the diet by cattle is described and the results discussed. Compared with the diet, urine had a lower ratio of ¹⁵N to ¹⁴N, but faeces, blood and milk all had a higher ratio. It is argued that the use of natural ¹⁵N as a tracer in grazed ecosystems is more complicated than was at first thought

    Denitrification by rhizobia: A possible factor contributing to nitrogen losses from soils

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    The intensive pastoral farming system on which New Zealand animal production is based is almost completely dependent upon the rhizobium-legurne symbiosis for the fixed nitrogen required for pasture production. The average annual fixation has been measured as 184 kg nitrogen/ha in developed lowland pastures Hoglund et cii., 1979 and about 13 kg nitrogen/ha in poorly developed bill country pastures (Grant and Lambert, 1979). From these figures it can be estimated that rhizobia in New Zealand pastures fix in excess of one million tonnes of nitrogen an nually. The current annual application of fertilizer nitrogen to pastures is about 12 500 tonnes (O'Connor, 1979)

    Simulation of the photodetachment spectrum of HHfO- using coupled-cluster calculations

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    The photodetachment spectrum of HHfO? was simulated using restricted-spin coupled-cluster single-double plus perturbative triple {RCCSD(T)} calculations performed on the ground electronic states of HHfO and HHfO?, employing basis sets of up to quintuple-zeta quality. The computed RCCSD(T) electron affinity of 1.67 ± 0.02 eV at the complete basis set limit, including Hf 5s25p6 core correlation and zero-point energy corrections, agrees well with the experimental value of 1.70 ± 0.05 eV from a recent photodetachment study [X. Li et al., J. Chem. Phys. 136, 154306 (2012)]. For the simulation, Franck-Condon factors were computed which included allowances for anharmonicity and Duschinsky rotation. Comparisons between simulated and experimental spectra confirm the assignments of the molecular carrier and electronic states involved but suggest that the experimental vibrational structure has suffered from poor signal-to-noise ratio. An alternative assignment of the vibrational structure to that suggested in the experimental work is presented

    Getting stuck or stepping back: effects of obstacles in the negotiation of creative solutions

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    "Difficult issues in negotiation act as interfering forces but their effects on negotiation processes and outcomes are unclear. Perhaps facing such obstacles leads individuals to take a step back, attend to the big picture and, therefore, to be able to craft creative, mutually beneficial solutions. Alternatively, facing obstacles may lead negotiators to focus narrowly on the obstacle issue, so that they no longer consider issues simultaneously, and forego the possibility to reach high quality, integrative agreements. Three experiments involving face-to-face negotiation support the “getting stuck” hypothesis, but only when negotiators are in a local processing mode and not when they are in a global processing mode. Implications for the art and science of negotiation, and for construal level theory, are discussed." [author's abstract

    Ab initio calculations on SF2 and its low-lying cationic states: Anharmonic Franck-Condon simulation of the uv photoelectron spectrum of SF2

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    Geometry optimization calculations were carried out on the X (1)A(1) state of SF2 and the X B-2(1), A (2)A(1), B B-2(2), C B-2(2), D (2)A(1), and E (2)A(2) states of SF2+ employing the restricted-spin coupled-cluster single-double plus perturbative triple excitation [RCCSD(T)] method and basis sets of up to the augmented correlation-consistent polarized quintuple-zeta [aug-cc-pV(5+d)Z] quality. Effects of core electron (S 2s(2)2p(6) and F 1s(2) electrons) correlation and basis set extension to the complete basis set limit on the computed minimum-energy geometries and relative electronic energies (adiabatic and vertical ionization energies) were investigated. RCCSD(T) potential energy functions (PEFs) were calculated for the X (1)A(1) state of SF2 and the low-lying states of SF2+ listed above employing the aug-cc-pV(5+d)Z and aug-cc-pV5Z basis sets for S and F, respectively. Anharmonic vibrational wave functions of these neutral and cationic states of SF2, and Franck-Condon (FC) factors of the lowest four one-electron allowed neutral photoionizations were computed employing the RCCSD(T) PEFs. Calculated FC factors with allowance for Duschinsky rotation and anharmonicity were used to simulate the first four photoelectron bands of SF2. The agreement between the simulated and observed first bands in the He I photoelectron spectrum reported by de Leeuw [Chem. Phys. 34, 287 (1978)] is excellent. Our calculations largely support assignments made by de Leeuw on the higher ionization energy bands of SF2

    Mejoramiento de los procesos en el quirófano mediante la aplicación de la metodología Lean de Toyota

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    ResumenEl sector de la atención en salud está necesitando un cambio fundamental a fin de mejorar significativamente los resultados y limitar al mismo tiempo los costos. Los métodos Lean desarrollados inicialmente en la industria manufacturera han demostrado mejorar realmente la calidad, la productividad y la seguridad, a la vez que permiten utilizar menos recursos en la gestión de la salud. Estas herramientas, prácticas gerenciales y filosofías se han adaptado con éxito en los servicios de cirugía del SC. Pueden transformar el sistema y la cultura mediante el compromiso del personal de asistencia para el desarrollo de un servicio que mejora continuamente y permite obtener mejores resultados clínicos duraderos.AbstractHealthcare is in need of fundamental change if we are going to make significant improvements in outcomes while limiting costs. Lean methods, initially developed in the manufacturing industry, have been shown to deliver real improvements in quality, productivity, and safety while using fewer resources in healthcare service settings. These tools, management practices and philosophies have been successfully adapted in operative services at SC. They can transform your system and culture through engagement of frontline staff into a continuously improving service with real and sustainable enhancements in clinical outcomes

    Development of a building sustainability assessment method (BSAM) for developing countries in sub-Saharan Africa

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    The consideration of the regional context in the development of green building rating systems is well established in the extant literature, and this informs the development of a sustainability assessment method for sub-Saharan Africa. Hence, a multi-expert consultation method was carried out in Nigeria which is the largest economy in the region. This was performed via a structured questionnaire survey and interview approaches to identify the key sustainability assessment criteria, assign score-weights to the various criteria, and establish the certification grading system of buildings. The developed Building Sustainability Assessment Method (BSAM) scheme and its weighted criteria were validated using two existing building case studies. The established BSAM scheme was compared to six widely used green building rating systems. The comparative analysis reveals that the score-weights and priorities of the BSAM scheme were remarkably different from the existing rating systems. The study findings also show the increasing focus on the indoor environmental quality and energy criteria by all the rating systems. The developed BSAM scheme, meanwhile, has adequately considered the three main pillars of sustainable development unlike the existing green rating tools. Hence, it is expected for the proposed BSAM scheme to promote greener buildings and enhance sustainable urban development in the region

    Barriers to the Integration of BIM and Sustainability Practices in Construction Projects: A Delphi Survey of International Experts

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    The built environment faces numerous challenges in its quest to be more productive and sustainable, and to the adoption of a smart and creative process of carrying out the various operations. This study aims to investigate the profound barriers faced by construction stakeholders in their attempts to integrate BIM and sustainability practices in the construction processes. A two-round Delphi survey formed the basis of aggregating consensus among the expert panel based on a set of 38 factors derived via content analysis of previous research studies. Descriptive and inferential tests were employed for data analysis, and the results validated using the interrater agreement analysis. The three key barriers by descending order of significance are industry's resistance to change from traditional working practices, an extended period of adapting to innovative technologies and the lack of understanding of the processes and workflows required for BIM and sustainability. Deductions were also made based on the comparative analysis of the expert groups. The findings will advance the implementation of BIM and sustainability practices in construction projects and enable project stakeholders to focus on addressing the critical challenges discussed in this study
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