5,596 research outputs found
Audit of surgical delay in relationship to outcome after proximal femoral fracture.
To ascertain the influence of surgical delay on outcome after proximal femoral fracture in elderly females, a cohort study of patients presenting in 1987 was compared to 1989/90. Organisational changes in the intervening period were introduced to reduce delay to surgical intervention. Two hundred and eighty females aged 65 years and over presenting from the local catchment area of an acute inner-city teaching hospital were enrolled in the study. Seventy-nine patients received surgery in 1987 and 186 in 1989/90. The one year mortality was 34% and 26% respectively. The proportion receiving surgery within 24 hours rose from 34% in 1987 to 57% in 1989/90. The relative hazard of the group receiving surgery on day 2 in comparison to day 1 was 1.7 (95% CI 1.0 to 2.9) when adjusted for co-variance of age and mental score. Medically fit elderly patients presenting with proximal femoral fracture have improved survival with early surgery within 24 hours of admission. Improvements in the organisation of hospital care will result in important benefits for the increasing number of elderly females presenting with proximal femoral fracture
Symbolic Algebra and Renormalization of Gauge Theories
Symbolic algebra relevant to the renormalization of gauge theories can be
efficiently performed by machine using modern packages. We devise a scheme for
representing and manipulating the objects involved in perturbative calculations
of gauge theories. This scheme is readily implemented using the general purpose
package, Mathematica. The techniques discussed are used to calculate
renormalization group functions for a non-abelian gauge theory with
massless fermions in a representation R, in the two-loop approximation, and to
simplify some expressions arising in electroweak calculations at the two loop
level.Comment: 16 pages, LaTex, 2 diagrams drawn with FEYNMAN, uses cite.sty Entire
manuscript available as a ps file at
http://www.physics.adelaide.edu.au/theory/home.html Also available via
anonymous ftp at ftp://adelphi.adelaide.edu.au/pub/theory/ADP-95-41.T193.ps
Accepted for publication in Computer Physics Communicatio
The global technical potential of bio-energy in 2050 considering sustainability constraints
Bio-energy, that is, energy produced from organic non-fossil material of biological origin, is promoted as a substitute for non-renewable (e.g., fossil) energy to reduce greenhouse gas (GHG) emissions and dependency on energy imports. At present, global bio-energy use amounts to approximately 50 EJ/yr, about 10% of humanity's primary energy supply. We here review recent literature on the amount of bio-energy that could be supplied globally in 2050, given current expectations on technology, food demand and environmental targets ('technical potential'). Recent studies span a large range of global bio-energy potentials from ≈30 to over 1000 EJ/yr. In our opinion, the high end of the range is implausible because of (1) overestimation of the area available for bio-energy crops due to insufficient consideration of constraints (e.g., area for food, feed or nature conservation) and (2) too high yield expectations resulting from extrapolation of plot-based studies to large, less productive areas. According to this review, the global technical primary bio-energy potential in 2050 is in the range of 160-270 EJ/yr if sustainability criteria are considered. The potential of bio-energy crops is at the lower end of previously published ranges, while residues from food production and forestry could provide significant amounts of energy based on an integrated optimization ('cascade utilization') of biomass flows. © 2010 Elsevier B.V
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