635 research outputs found
Simulation of river flow in the Thames over 120 years: evidence of change in rainfall-runoff response?
Study region: The Thames catchment in southern England, UK.
Study focus: Modelling with 124 years of rainfall, potential evaporation (PE), temperature and naturalised flow data. Daily rainfall-runoff flow simulation using current and three historic land cover scenarios to determine the stationarity of catchment response examined through three time-frames of analysis – annual, seasonal and flow extremes. The criterion of response stationarity is often assumed in climate change impact studies.
New hydrological insights: The generally close correspondence between observed and simulated flows using the same model parameter values for the whole period is indicative of the temporal stability of hydrological processes and catchment response, and the quality of the hydrometric data. Changes that have occurred are a decrease in flood peak response times, typically two to three days pre and post the early 1940s, from change in agricultural practices and channel conveyance, and an increase of about 15% in summer flow from increase in urban land cover between the first decade of the 20th and 21st centuries. The water balance was found to be sensitive to the PE data used, with care needed to avoid discontinuity between two parts of the data record using different methods for calculation. Long-term mean annual rainfall shows little change but contrasting patterns of variation in seasonal rainfall demonstrate a variable climate for which simulated flow is similar to observed flow
An investigation of the effect of transient climate change on snowmelt, flood frequency and timing in northern Britain
Climate change is almost certain to affect snow and ice processes. Even at lower latitudes, changes in snow cover at high altitudes can significantly affect catchment hydrology. This paper uses data from a transient Regional Climate Model projection (HadRM3Q0) for 1950-2099 (A1B emissions) to drive hydrological models for three nested catchments on the river Dee in north-east Scotland, to assess potential changes in flood frequency and timing using annual maxima and moving-window analyses. Some results are also shown for an upland catchment in northern England. Modelling is performed both with and without a snow module, to demonstrate the effects of snowfall/melt and how these change through time and vary between catchments. Modelled changes in flood magnitude and timing are non-linear, with most changes for daily mean flows not significant. For longer duration (30-day) flows with snow there are significant decreases in peak magnitude, particularly for the smaller higher altitude Dee catchments, with peaks occurring months earlier in future (changes without snow are generally not significant). There is a general convergence in results with and without snow later in the period, as snow processes become less important, but convergence occurs at different times for different catchments and occurs differently for daily and 30-day peak flows due to the differential effects of snow at different durations. This highlights the importance of including snow processes for such catchments, particularly for longer duration flows, but also highlights the complexity of interactions: Physical catchment properties, the balance between precipitation occurrence and temperature, and how this balance alters as the climate changes will each be critical in determining the impact on the magnitude and timing of peak flows, making it hard to generalise results
Regionalisation of climate impacts on flood flows to support the development of climate change guidance for Flood Management
Current Defra / Environment Agency guidance (FCDPAG3 supplementary note: http://www.defra.gov.uk/environ/fcd/pubs/pagn/climatechangeupdate.pdf) requires all flood management plans to allow for climate change by incorporating, within a sensitivity analysis, an increase in river flows of up 20% over the next 50 years, and beyond. This guidance is the same for all of England and Wales, making no allowance for regional variation in climate change or catchment type. This reflects the lack of scientific evidence to resolve the spatial distribution of potential impacts on flood flows with enough confidence to set such policy regionally. The 20% allowance was first raised in 1999 for MAFF and subsequently reviewed following the release of the UKCIP02 scenarios. Although the 20% figure is a memorable precautionary target, there is the risk that it leads to a significant under- or over-estimation of future flood risk in individual catchments.
Defra and the Environment Agency procured project FD2020 (Regionalisation of climate change impacts on flood flows) to provide a more rigorous science base for refreshing the FCDPAG3: supplementary note guidance. The FD2020 approach is exploring the relationships between catchment characteristics and climate change impacts on peak flows in a “scenario neutral” way. This is done by defining a regular set of changes in climate that encompass all the current knowledge from the new scenarios available from the IPCC Fourth Assessment Report. For each of the 155 catchments included in the research, this broad approach will provide multiple scenarios to produce a “vulnerability surface” for change in the metrics of peak flows (e.g. the 20-year flood flow). Some of the UKCP09 products have also been used to understand what these projections may mean for changes to peak flow. The catchment-based analysis will be used to generalise to other gauged sites across Britain, using relationships with catchment characteristics, providing the scientific evidence for the development of regional guidance on climate change allowances.
Specifically the project is:
Investigating the impact of climate change on peak river flows in over 150 catchments across Britain to assess the suitability of the FCDPAG3 20% climate change allowance.
Investigating catchment response to climate change to identify potential similarities such that the FCDPAG3 nationwide allowance could be regionalised.
Investigating the uncertainty in changes to future peak river flows from climate change.
Developing an approach that has longevity beyond the project timeframe and the lifetime of the latest generation of climate model results
Proteomic profiling of bovine M. longissimus lumborum from Crossbred Aberdeen Angus and Belgian Blue sired steers varying in genetic merit for carcass weight
Bovine skeletal muscle is a tissue
of significant value to the beef industry and global
economy. Proteomic analyses offer the opportunity to
detect molecular mechanisms regulating muscle growth
and intramuscular fat accumulation. The current study
aimed to investigate differences in protein abundance
in skeletal muscle tissue of cattle from two breeds of
contrasting maturity (early vs. late maturing), adiposity,
and muscle growth potential, namely, Belgian Blue
(BB) × Holstein Friesian and Aberdeen Angus (AA) ×
Holstein Friesian. Twenty AA (n = 10) and BB (n = 10)
sired steers, the progeny of sires of either high or low
genetic merit, expressed as expected progeny difference
for carcass weight (EPDcwt), and bred through
AI, were evaluated as 4 genetic groups, BB-High,
BB-Low, AA-High, and AA-Low (n = 5 per treatment).
Chemical composition analysis of M. longissimus
lumborum showed greater protein and moisture and
decreased lipid concentrations for BB-sired compared
with AA-sired steers. To investigate the effects
of both sire breed and EPDcwt on M. longissimus
lumborum, proteomic analysis was performed using
2-dimensional difference gel electrophoresis followed by mass spectrometry. Proteins were identified from
their peptide sequences, using the National Center for
Biotechnology Information (NCBI) and Swiss-prot
databases. Metabolic enzymes involved in glycolysis
(glycogen phosphorylase, phosphoglycerate mutase)
and the citric acid cycle (aconitase 2, oxoglutarate
dehydrogenase) were increased in AA- vs. BB-sired
steers. Expression of proteins involved in cell structure,
such as myosin light chain isoforms and troponins I
and T, were also altered due to sire breed. Furthermore,
heat shock protein β-1 and peroxiredoxin 6, involved
in cell defense, had increased abundance in muscle of
AA-sired relative to BB-sired steers. Protein abundance
of glucose-6-phosphate isomerase, enolase-3, and
pyruvate kinase was greater in AA-sired animals of
High compared with Low EPDcwt. Changes in the
expression of these proteins were supported by gene
expression analysis using quantitative real-time PCR.
This information will aid in our understanding of
genetic infl uences controlling muscle growth and fat
accumulation and could contribute to future breeding
programs to increase lean tissue gain of beef cattle
On Entangled Multi-particle Systems in Bohmian Theory
Arguments are presented to show that in the case of entangled systems there
are certain difficulties in implementing the usual Bohmian interpretation of
the wave function in a straightforward manner. Specific examples are given.Comment: 7 page
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Ten years of challenge : the impact of the external environment on charity fundraising and marketing 1989-1999
Change happens constantly, but sometimes several factors coincide, becoming a catalyst for major change. At the beginning of the 1990s there were indications that this was the case for fundraisers. This research begins by going behind the headlines to examine the external environment between 1989 and 1994 and its impact on voluntary fundraising. The research uses a qualitative approach and a grounded theory methodology to examine the changing environment as experienced by 30 heads of fundraising from charities of all sizes. Was the external environment making fundraising more difficult? If so, how were fundraisers responding, what strategies and structures were they adopting? Did it include marketing? From the research one expectation, that charities with large voluntary incomes would have replica fundraising departments, was found not to be the case. Further investigation showed that there was a life cycle for fundraising which was not necessarily in step with the charity as a whole. This discovery through the grounded theory approach led to the five-stages of fundraising, a framework for the development of charity fundraising. The framework identified a number of variables and criteria but also used organisation culture theory to contextualise fundraisers' comments. The framework helped to make sense of some charities' unexpected responses to the questions. Writing up was finished in 1999. A short longitudinal study was then added to compare the impact of the external environment in the second half of the 1990s with that of the first half. The longitudinal study also enabled further testing of the five stages theory to assess its ongoing validity and wider relevance to the sector. Therefore, this research comprises three elements: the original study, the five stages framework and the longitudinal study. It explores the full impact of external changes on fundraising and how fundraisers have responded through the decade
Learning to rank from medical imaging data
Medical images can be used to predict a clinical score coding for the
severity of a disease, a pain level or the complexity of a cognitive task. In
all these cases, the predicted variable has a natural order. While a standard
classifier discards this information, we would like to take it into account in
order to improve prediction performance. A standard linear regression does
model such information, however the linearity assumption is likely not be
satisfied when predicting from pixel intensities in an image. In this paper we
address these modeling challenges with a supervised learning procedure where
the model aims to order or rank images. We use a linear model for its
robustness in high dimension and its possible interpretation. We show on
simulations and two fMRI datasets that this approach is able to predict the
correct ordering on pairs of images, yielding higher prediction accuracy than
standard regression and multiclass classification techniques
El Acaparamiento de Tierras en América Latina y el Caribe Visto Desde una Perspectiva Internacional más Amplia
Introducción y mensajes claves
Este documento se basa en la investigación empírica que fue encomendada por la Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO) sobre las condiciones y tendencias del ―acaparamiento de tierras‖ en 17 países de América Latina y el Caribe (véase el Anexo para una lista completa de los estudios, así como el documento síntesis correspondiente; FAO, 2011). Los 17 estudios se concluyeron a mediados de 2011. El marco analítico común de los estudios es amplio, pero a la vez focalizado. Por un lado es amplio porque analiza los procesos generales de las tierras rurales y la concentración de capital en el contexto de la globalización neoliberal. Por el otro, es focalizado porque analiza el fenómeno del ―acaparamiento de tierras‖ basándose estrictamente en tres dimensiones específicas, a saber: i) el gran alcance de las adquisiciones de tierra a gran escala; ii) la participación de los gobiernos extranjeros en estos tratos sobre tierras; y iii) el impacto negativo de dichas inversiones recientes en tierras sobre la seguridad alimentaria del país receptor. Es en gran medida debido a este tipo de marco analítico que la mayoría de los estudios pudieron desentrañar y recopilar gran cantidad de material empírico relacionado con la dinámica de las tierras en la región; sin embargo, dado que el enfoque de su análisis y conclusiones se basó en la definición y la dimensión angostas del acaparamiento de tierras, la conclusión obtenida fue que el ―acaparamiento de tierras‖ se da únicamente en dos países de la región: Argentina y Brasil. ..
Acaparamiento de tierras y acumulación capitalista: aspectos clave en América Latina
__Abstract__
We introduce this special issue by explaining seven characteristics
of land grabbing in Latin America. These features are not unique
to the region. By highlighting them – arguing, for instance, that a
key aspect in Latin America is intra-regional land grabbing driven
by (trans)Latina companies – we hope to inspire new cross-regional
comparisons to understand the dynamics of “global” land grabbing.
Our focus on Latin America challenges some problematic generalisations
in the literature, for instance, that land grabs occur mainly
in fragile states. We interrogate the relationship between land grabbing
and the “foreignisation” narrative, and the need to revisit the
broader question of land concentration. Thus we build upon the literature
locating land grabs and the land question within the political
economy of global capitalism
Nutrient concentration relationships between the fourth petiole and upper-stem of potato plants
Successfully evaluating the nutritional status of a crop during growth
and development is dependent upon sampling an identifiable plant part.
Consistently sampling a petiole of the same maturity in potatoes (Solanum
tuberosum L.) is difficult. We evaluated the nutrient relationships between
the upper-stem and the fourth petiole from Russet Burbank plants in field
studies having N, P, K, Zn or Mn variables. The upper-stem was obtained by
excising the stem below the sixth leaf and removing all leaves and the terminal
meristem. Petole NO3-N, P, K, Zn and Mn concentrations were from
deficient to sufficient. The NO 3-N, P and K concentrations were similar in
the fourth petiole and upper-stem, while the Zn concentration was 40%
higher in the upper-stem. Calcium, Mg and Mn concentrations were lower
in the upper-stem than in the fourth petiole. Copper and S relationships
were not adequately defined. The fourth petiole's NO 3-N, P and K diagnostic
concentrations now used to monitor plant nutrient status can also be
used for upper-stem samples. Zinc diagnostic concentrations should be increased,
while Ca, Mg and Mn concentrations should be adjusted downward
in the upper-tem. Additional data are needed to refine the Ca and Mg
relationships, and to establish relationships for Cu, S and other essential
nutrients. A significant advantage of using the upper-stem is the elimination
of the petiole selection problem when sampling
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