580 research outputs found

    Exploring network structure and the role of key stakeholders to understand the obesity prevention system in an Australian metropolitan health service: Study protocol

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    Introduction: Little progress has been made to address the increasing obesity prevalence over the past few decades, and there is growing concern about the far-reaching consequences for health and well-being related to obesity on a global scale. Systems thinking is emerging as a suitable approach for obesity prevention, as it allows health researchers, practitioners and policy-makers to systematically synthesise existing data, expose gaps, inform priority setting and identify leverage points in the system. The aim of this study is to trial a systems thinking approach to better understand the local obesity prevention system, and identify gaps and viable opportunities for health promotion activities to strengthen obesity prevention efforts in an Australian metropolitan health service. Methods and analysis: A mixed methods design will be undertaken in a metropolitan health service area in Perth, Western Australia in 2019-2020. A systems inventory audit will be used to identify physical activity, nutrition and overweight/obesity prevention activities taking place in the study area. An organisational network survey will be administered, and a social network analysis undertaken to examine relationships between organisations in the network. The relationships and interactions will compare the level and type of interactions each organisation has within the network. Parameters including density, centrality and betweenness will be computed using UCINET and Netdraw. Ethics and dissemination: Ethics approval has been obtained from the Curtin University Human Research Ethics Committee (approval number HRE2017-0862). Results will be reviewed with members of the advisory group, submitted to relevant journals and presented at relevant conferences to health promotion practitioners and policy-makers. The area health service, as co-producers of the research, will use findings to inform policy and strategy across the study area

    Direct Observation by Scanning Tunneling Microscopy of the Two-Dimensional Lattice Structure of the S-Layer Sheath of the Archaeobacterium Methanospirillum hungatei GP1

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    Observation of the two-dimensional (2-D) 3 nm x 3 nm lattice structure of the S-layer sheath of the archaeobacterium Methanospirillum hungatei is reported for the first time by scanning tunneling microscopy. The samples consisted of sheath fragments deposited on a TaSe2 substrate and coated with a Pt/Ir film. In addition to confirming the 2-D structure, the images reveal some new information about the nano-scale details of the sheath structure. A lateral resolution of 1 nm was achieved, suggesting that the grain size of the Pt/Ir films was much less than for similar films deposited on a smooth metal surface

    Sorting Strategies for Long Yearling Cattle Grown in an Extensive Forage Utilization Beef Production System

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    One hundred sixty English-cross steers (244 kg, SD=23 kg) were used in each yr of a 2-yr study to determine effects of sorting on performance, carcass characteristics, variability, and profitability in a long yearling system utilizing ranch-source calves. Steers were back grounded during winter then grazed smooth brome-grass pastures followed by warm season native range prior to entering the feedlot in the fall. Steers were stratified by BW and allotted to 1 of 4 treatments: 1) 40 head sorted by pre-grazing BW where heavy steers entered the feedlot in July (PST), 2) 40 head sorted by BW entering the feedlot (FDL), 3) 60 head sorted by BW and fat thickness at the end of the feeding period (IND), and 4) 20 head that were not sorted (UNS). No differences were observed for performance during back-grounding or grazing phases (P \u3e 0.30). Cattle receiving PST sorting weighed less entering the feedlot and consumed less feed with less feedlot ADG compared to other treatments (P \u3c 0.05). No differences in feed efficiencies were detected (P = 0.84). Cattle receiving PST sorting had greater marbling scores (P \u3c 0.05) and less variation in BW upon feedlot entry which resulted in less variation in carcass weight compared with UNS (P \u3c 0.05). Cattle sorted by BW entering the feedlot tended (P = 0.08) to have less variation in carcass weight compared with UNS. There were no differences in carcass weight or profitability when calculated on either a live or value basis. No sorting strategy increased carcass weight, reduced discounts for overweight or corpulent carcasses, or improved profitability over UNS

    Sorting Strategies for Long Yearling Cattle Grown in an Extensive Forage Utilization Beef Production System

    Get PDF
    One hundred sixty English-cross steers (244 kg, SD=23 kg) were used in each yr of a 2-yr study to determine effects of sorting on performance, carcass characteristics, variability, and profitability in a long yearling system utilizing ranch-source calves. Steers were back grounded during winter then grazed smooth brome-grass pastures followed by warm season native range prior to entering the feedlot in the fall. Steers were stratified by BW and allotted to 1 of 4 treatments: 1) 40 head sorted by pre-grazing BW where heavy steers entered the feedlot in July (PST), 2) 40 head sorted by BW entering the feedlot (FDL), 3) 60 head sorted by BW and fat thickness at the end of the feeding period (IND), and 4) 20 head that were not sorted (UNS). No differences were observed for performance during back-grounding or grazing phases (P \u3e 0.30). Cattle receiving PST sorting weighed less entering the feedlot and consumed less feed with less feedlot ADG compared to other treatments (P \u3c 0.05). No differences in feed efficiencies were detected (P = 0.84). Cattle receiving PST sorting had greater marbling scores (P \u3c 0.05) and less variation in BW upon feedlot entry which resulted in less variation in carcass weight compared with UNS (P \u3c 0.05). Cattle sorted by BW entering the feedlot tended (P = 0.08) to have less variation in carcass weight compared with UNS. There were no differences in carcass weight or profitability when calculated on either a live or value basis. No sorting strategy increased carcass weight, reduced discounts for overweight or corpulent carcasses, or improved profitability over UNS

    The symmetric-Toeplitz linear system problem in parallel

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    [EN] Many algorithms exist that exploit the special structure of Toeplitz matrices for solving linear systems. Nevertheless, these algorithms are difficult to parallelize due to its lower computational cost and the great dependency of the operations involved that produces a great communication cost. The foundation of the parallel algorithm presented in this paper consists of transforming the Toeplitz matrix into a another structured matrix called Cauchy¿like. The particular properties of Cauchy¿like matrices are exploited in order to obtain two levels of parallelism that makes possible to highly reduce the execution time. The experimental results were obtained in a cluster of PC¿s.Supported by Spanish MCYT and FEDER under Grant TIC 2003-08238-C02-02Alonso-Jordá, P.; Vidal Maciá, AM. (2005). The symmetric-Toeplitz linear system problem in parallel. Computational Science -- ICCS 2005,Pt 1, Proceedings. 3514:220-228. https://doi.org/10.1007/11428831_28S2202283514Sweet, D.R.: The use of linear-time systolic algorithms for the solution of toeplitz problems. k Technical Report JCU-CS-91/1, Department of Computer Science, James Cook University, Tue, 23 April 1996 15, 17, 55 GMT (1991)Evans, D.J., Oka, G.: Parallel solution of symmetric positive definite Toeplitz systems. Parallel Algorithms and Applications 12, 297–303 (1998)Gohberg, I., Koltracht, I., Averbuch, A., Shoham, B.: Timing analysis of a parallel algorithm for Toeplitz matrices on a MIMD parallel machine. Parallel Computing 17, 563–577 (1991)Gallivan, K., Thirumalai, S., Dooren, P.V.: On solving block toeplitz systems using a block schur algorithm. In: Proceedings of the 23rd International Conference on Parallel Processing, Boca Raton, FL, USA, vol. 3, pp. 274–281. CRC Press, Boca Raton (1994)Thirumalai, S.: High performance algorithms to solve Toeplitz and block Toeplitz systems. Ph.d. th., Grad. College of the U. of Illinois at Urbana–Champaign (1996)Alonso, P., Badía, J.M., Vidal, A.M.: Parallel algorithms for the solution of toeplitz systems of linear equations. In: Wyrzykowski, R., Dongarra, J., Paprzycki, M., Waśniewski, J. (eds.) PPAM 2004. LNCS, vol. 3019, pp. 969–976. Springer, Heidelberg (2004)Anderson, E., et al.: LAPACK Users’ Guide. SIAM, Philadelphia (1995)Blackford, L., et al.: ScaLAPACK Users’ Guide. SIAM, Philadelphia (1997)Alonso, P., Badía, J.M., González, A., Vidal, A.M.: Parallel design of multichannel inverse filters for audio reproduction. In: Parallel and Distributed Computing and Systems, IASTED, Marina del Rey, CA, USA, vol. II, pp. 719–724 (2003)Loan, C.V.: Computational Frameworks for the Fast Fourier Transform. SIAM Press, Philadelphia (1992)Heinig, G.: Inversion of generalized Cauchy matrices and other classes of structured matrices. Linear Algebra and Signal Proc., IMA, Math. Appl. 69, 95–114 (1994)Gohberg, I., Kailath, T., Olshevsky, V.: Fast Gaussian elimination with partial pivoting for matrices with displacement structure. Mathematics of Computation 64, 1557–1576 (1995)Alonso, P., Vidal, A.M.: An efficient and stable parallel solution for symmetric toeplitz linear systems. TR DSIC-II/2005, DSIC–Univ. Polit. Valencia (2005)Kailath, T., Sayed, A.H.: Displacement structure: Theory and applications. SIAM Review 37, 297–386 (1995

    Impact potential of hypersaline brines released into the marine environment for CCS reservoir pressure management

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    The environmental impact potential arising from the possible disposal of hypersaline brines into the ocean as part of reservoir pressure management for Carbon Capture and Storage is assessed using sophisticated high-resolution hydrodynamic models for the first time, investigating several industry guided scenarios. Although the characteristics of some brines in their undiluted form would have a high environmental impact potential, we find that dispersion in a hydrodynamically active region like the North Sea acts to dilute disposed brine rapidly, even in a worst case approach, such that the potential impact footprint (area exposed to environmentally damaging salinity or temperature) is small, measured in 10’s of meters depending on the release scenario and site specific data such as the hypersaline water contaminants along with in-situ conditions such as currents and mixing. The method of brine disposal has a significant influence on dispersal, such that brines released nearer the sea surface disperse more rapidly, compared with release at the seabed. Hence consideration of brine release height is recommended to further limit impact potentia
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