618 research outputs found
Impacts of CO2-taxes in an economy with niche markets and learning-by-doing.
[Dataset available: http://hdl.handle.net/10411/16384]
Converting Waste Toilet Paper into Electricity:A First-Stage Technoeconomic Feasibility Study
Exploring the causes of adverse events in hospitals and potential prevention strategies
Objectives
To examine the causes of adverse events
(AEs) and potential prevention strategies to minimise the
occurrence of AEs in hospitalised patients.
Methods
For the 744 AEs identified in the patient record
review study in 21 Dutch hospitals, trained reviewers
were asked to select all causal factors that contributed
to the AE. The results were analysed together with data
on preventability and consequences of AEs. In addition,
the reviewers selected one or more prevention strategies
for each preventable AE. The recommended prevention
strategies were analysed together with four general
causal categories: technical, human, organisational and
patient-related factors.
Results
Human causes were predominantly involved in
the causation of AEs (in 61% of the AEs), 61% of those
being preventable and 13% leading to permanent
disability. In 39% of the AEs, patient-related factors were
involved, in 14% organisational factors and in 4%
technical factors. Organisational causes contributed
relatively often to preventable AEs (93%) and AEs
resulting in permanent disability (20%). Recommended
strategies to prevent AEs were quality assurance/peer
review, evaluation of safety behaviour, training and
procedures. For the AEs with human and patient-related
causes, reviewers predominantly recommended quality
assurance/peer review. AEs caused by organisational
factors were considered preventable by improving
procedures.
Discussion
Healthcare interventions directed at human
causes are recommended because these play a large
role in AE causation. In addition, it seems worthwhile to
direct interventions on organisational causes because the
AEs they cause are nearly always believed to be
preventable. Organisational factors are thus relatively
easy to tackle. Future research designs should allow
researchers to interview healthcare providers that were
involved in the event, as an additional source of
information on contributing factors.
Comparing Galaxies and Lyman Alpha Absorbers at Low Redshift
A scenario is explored in which Lyman alpha absorbers at low redshift arise
from lines of sight through extended galaxy disks, including those of dwarf and
low surface brightness galaxies. A population of galaxies is simulated based
upon observed distributions of galaxy properties, and the gas disks are modeled
using pressure and gravity confinement. Some parameter values are ruled out by
comparing simulation results with the observed galaxy luminosity function, and
constraints may be made on the absorbing cross sections of galaxies. Simulation
results indicate that it is difficult to match absorbers with particular
galaxies observationally since absorption typically occurs at high impact
parameters (>200 kpc) from luminous galaxies. Low impact parameter absorption
is dominated by low luminosity dwarfs. A large fraction of absorption lines is
found to originate from low surface brightness galaxies, so that the absorbing
galaxy is likely to be misidentified. Low redshift Lyman alpha absorber counts
can easily be explained by moderately extended galaxy disks when low surface
brightness galaxies are included, and it is easily possible to find a scenario
which is consistent with observed the galaxy luminosity function, with low
redshift Lyman limit absorber counts, and with standard nucleosynthesis
predictions of the baryon density, Omega_Baryon.Comment: 17 pages, 8 figures, accepted to the Astrophysical Journa
The Tully-Fisher relation for low surface brightness galaxies - implications for galaxy evolution
We present the B band Tully-Fisher relation for Low Surface Brightness (LSB)
galaxies. These LSB galaxies follow the same Tully-Fisher relation as normal
spiral galaxies. This implies that the mass-to-light ratio (M/L) of LSB
galaxies is typically a factor of 2 larger than that of normal galaxies of the
same total luminosity and morphological type. Since the dynamical mass of a
galaxy is related to the rotation velocity and scale length via M \propto V^2
h, at fixed linewidth LSB galaxies must be twice as large as normal galaxies.
This is confirmed by examining the relation between scale length and linewidth
for LSB and normal galaxies. The universal nature of the Tully-Fisher relation
can be understood if LSB galaxies are galaxies with low mass surface density,
\sigma. The mass surface density apparently controls the luminosity evolution
of a galaxy such as to keep the product \sigma M/L constant.Comment: 9 pages, PostScript. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Energy Investments under Climate Policy: A Comparison of Global Models
The levels of investment needed to mobilize an energy system transformation and mitigate climate change are not known with certainty. This paper aims to inform the ongoing dialogue and in so doing to guide public policy and strategic corporate decision making. Within the framework of the LIMITS integrated assessment model comparison exercise, we analyze a multi-IAM ensemble of long-term energy and greenhouse gas emissions scenarios. Our study provides insight into several critical but uncertain areas related to the future investment environment, for example in terms of where capital expenditures may need to flow regionally, into which sectors they might be concentrated, and what policies could be helpful in spurring these financial resources. We find that stringent climate policies consistent with a 2 degrees C climate change target would require a considerable upscaling of investments into low-carbon energy and energy efficiency, reaching approximately 30-75 trillion) cumulative between 2010 and 2050, or about 30 trillion (0.8 trillion per year, beyond what investments might otherwise be in a reference scenario that assumes the continuation of present and planned emissions-reducing policies throughout the world. In other words, a substantial "clean-energy investment gap" of some 523 billion). Unless the gap is filled rather quickly, the 2 degrees C target could potentially become out of reach
Endogenous Technological Change in Climate Change Modeling
This article investigates the impact on optimal CO2 abatement and carbon tax levels of introducing endogenous technological change in a macroeconomic model of climate change. We analyze technological change as a function of cumulative capacity, as incorporated recently in energy-systems models. Our calculations confirm that including endogenous innovation implies earlier emission reduction to meet atmospheric carbon concentration constraints. However, the effect is stronger than suggested in the literature. Moreover, the development on non-fossil energy technologies constitutes the most important opportunity for emission reductions. Optimal carbon tax levels, reducing fossil energy use, are lower than usually advocated
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