10,841 research outputs found
Vulnerability of the agricultural sector to climate change: The development of a pantropical Climate Risk Vulnerability Assessment to inform sub-national decision making
As climate change continues to exert increasing pressure upon the livelihoods and agricultural sector of many developing and developed nations, a need exists to understand and prioritise at the sub national scale which areas and communities are most vulnerable. The purpose of this study is to develop a robust, rigorous and replicable methodology that is flexible to data limitations and spatially prioritizes the vulnerability of agriculture and rural livelihoods to climate change. We have applied the methodology in Vietnam, Uganda and Nicaragua, three contrasting developing countries that are particularly threatened by climate change. We conceptualize vulnerability to climate change following the widely adopted combination of sensitivity, exposure and adaptive capacity. We used Ecocrop and Maxent ecological models under a high emission climate scenario to assess the sensitivity of the main food security and cash crops to climate change. Using a participatory approach, we identified exposure to natural hazards and the main indicators of adaptive capacity, which were modelled and analysed using geographic information systems. We finally combined the components of vulnerability using equal-weighting to produce a crop specific vulnerability index and a final accumulative score. We have mapped the hotspots of climate change vulnerability and identified the underlying driving indicators. For example, in Vietnam we found the Mekong delta to be one of the vulnerable regions due to a decline in the climatic suitability of rice and maize, combined with high exposure to flooding, sea level rise and drought. However, the region is marked by a relatively high adaptive capacity due to developed infrastructure and comparatively high levels of education. The approach and information derived from the study informs public climate change policies and actions, as vulnerability assessments are the bases of any National Adaptation Plans (NAP), National Determined Contributions (NDC) and for accessing climate finance
Cesaro mean distribution of group automata starting from measures with summable decay
Consider a finite Abelian group (G,+), with |G|=p^r, p a prime number, and F:
G^N -> G^N the cellular automaton given by {F(x)}_n= A x_n + B x_{n+1} for any
n in N, where A and B are integers relatively primes to p. We prove that if P
is a translation invariant probability measure on G^Z determining a chain with
complete connections and summable decay of correlations, then for any w=
(w_i:i<0) the Cesaro mean distribution of the time iterates of the automaton
with initial distribution P_w --the law P conditioned to w on the left of the
origin-- converges to the uniform product measure on G^N. The proof uses a
regeneration representation of P
The Cape rapidly oscillating Ap star survey
Bibliography: p. 321-330.This thesis describes a survey, the Cape Survey, which was started with the intention of discovering more roAp stars suitable for asteroseismological studies and also to identify the limits of the roAp phenomenon in temperature and luminosity. This is the most extensive survey of the roAp phenomenon to date. Prior to the start of the Cape Survey, only 14 roAp stars, discovered over a period of 12 years, were known. The Cape Survey has yielded another 10 new roAp stars in the past three years. The candidates for the Cape Survey were mostly drawn from the Ap SrCrEu stars in the Michigan Spectral Catalogue
Automatic Metro Map Layout Using Multicriteria Optimization
This paper describes an automatic mechanism for drawing metro maps. We apply multicriteria optimization to find effective placement of stations with a good line layout and to label the map unambiguously. A number of metrics are defined, which are used in a weighted sum to find a fitness value for a layout of the map. A hill climbing optimizer is used to reduce the fitness value, and find improved map layouts. To avoid local minima, we apply clustering techniques to the map the hill climber moves both stations and clusters when finding improved layouts. We show the method applied to a number of metro maps, and describe an empirical study that provides some quantitative evidence that automatically-drawn metro maps can help users to find routes more efficiently than either published maps or undistorted maps. Moreover, we found that, in these cases, study subjects indicate a preference for automatically-drawn maps over the alternatives
Microscopic Theory of Protein Folding Rates.II: Local Reaction Coordinates and Chain Dynamics
The motion involved in barrier crossing for protein folding are investigated
in terms of the chain dynamics of the polymer backbone, completing the
microscopic description of protein folding presented in the previous paper.
Local reaction coordinates are identified as collective growth modes of the
unstable fluctuations about the saddle-points in the free energy surface. The
description of the chain dynamics incorporates internal friction (independent
of the solvent viscosity) arising from the elementary isomerizations of the
backbone dihedral angles. We find that the folding rate depends linearly on the
solvent friction for high viscosity, but saturates at low viscosity because of
internal friction. For -repressor, the calculated folding rate
prefactor, along with the free energy barrier from the variational theory,
gives a folding rate that agrees well with the experimentally determined rate
under highly stabilizing conditions, but the theory predicts too large a
folding rate at the transition midpoint. This discrepancy obtained using a
fairly complete quantitative theory inspires a new set of questions about chain
dynamics, specifically detailed motions in individual contact formation.Comment: 18 pages, 8 figure
New Measurements with Stopped Particles at the LHC
Metastable particles are common in many models of new physics at the TeV
scale. If charged or colored, a reasonable fraction of all such particles
produced at the LHC will stop in the detectors and give observable out of time
decays. We demonstrate that significant information may be learned from such
decays about the properties (e.g. charge or spin) of this particle and of any
other particles to which it decays, for example a dark matter candidate. We
discuss strategies for measuring the type of decay (two- vs three-body), the
types of particles produced, and the angular distribution of the produced
particles using the LHC detectors. We demonstrate that with O(10-100) observed
decay events, not only can the properties of the new particles be measured but
indeed even the Lorentz structure of the decay operator can be distinguished in
the case of three-body decays. These measurements can not only reveal the
correct model of new physics at the TeV scale, but also give information on
physics giving rise to the decay at energy scales far above those the LHC can
probe directly.Comment: 31 pages, 6 figures. References added, updated to reflect recent
experimental results, version accepted for publication in Physical Review
Blood loss in primary total knee arthroplasty-body temperature is not a significant risk factor-a prospective, consecutive, observational cohort study
BACKGROUND: Hypothermia related to anaesthesia and operating theatre environment is associated with increased blood loss in a number of surgical disciplines, including total hip arthroplasty. The influence of patient temperature on blood loss in total knee arthroplasty (TKA) has not been previously studied. METHODS: We recorded patient axillary temperature in the peri-operative period, up to 24 h post-operatively, and analysed the effect on transfusion rate and blood loss from a consecutive cohort of 101 patients undergoing primary TKA. RESULTS: No relationship between peri-operative patient temperature and blood loss was found within the recorded patient temperature range of 34.7–37.8 °C. Multivariable analysis found increasing age, surgical technique, type of anaesthesia and the use of anti-platelet and anticoagulant medications as significant factors affecting blood loss following TKA. CONCLUSION: Patient temperature within a clinically observed range does not have a significant impact on blood loss in primary TKA patients. As long as patient temperature is maintained within a reasonable range during the intra-operative and post-operative periods, strategies other than rigid temperature control above 36.5 °C may be more effective in reducing blood loss following TKA
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A diagnosis of low-order dynamics in the atmosphere of Mars
Introduction: There is considerable evidence that shows that the Martian atmosphere behaves in a more regular fashion than its terrestrial counterpart [1, 2, 3, 4]. This evidence leads to the hypothesis of theMartian climate attractor being of a relatively low dimension, which, in turn, would imply the possibility of describing the state of the atmosphere by means of a relatively few degrees of freedom. We explore this hypothesis by assuming that the atmospheric total energy (TE), i.e. the sum of kinetic energy and total potential energy (gravitational potential energy plus internal energy), is confined in a few coherent structures which dynamically interact nonlinearly with each other
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