5,824 research outputs found
Linking Research and Policy: Assessing a Framework for Organic Agricultural Support in Ireland
This paper links social science research and agricultural policy through an analysis of support for organic agriculture and food. Globally, sales of organic food have experienced 20% annual increases for the past two decades, and represent the fastest growing segment of the grocery market. Although consumer interest has increased, farmers are not keeping up with demand. This is partly due to a lack of political support provided to farmers in their transition from conventional to organic production. Support policies vary by country and in some nations, such as the US, vary by state/province. There have been few attempts to document the types of support currently in place. This research draws on an existing Framework tool to investigate regionally specific and relevant policy support available to organic farmers in Ireland. This exploratory study develops a case study of Ireland within the framework of ten key categories of organic agricultural support: leadership, policy, research, technical support, financial support, marketing and promotion, education and information, consumer issues, inter-agency activities, and future developments. Data from the Irish Department of Agriculture, Fisheries and Food, the Irish Agriculture and Food Development Authority (Teagasc), and other governmental and semi-governmental agencies provide the basis for an assessment of support in each category. Assessments are based on the number of activities, availability of information to farmers, and attention from governmental personnel for each of the ten categories. This policy framework is a valuable tool for farmers, researchers, state agencies, and citizen groups seeking to document existing types of organic agricultural support and discover policy areas which deserve more attention
mSpace meets EPrints: a Case Study in Creating Dynamic Digital Collections
In this case study we look at issues involved in (a) generating dynamic digital libraries that are on a particular topic but span heterogeneous collections at distinct sites, (b) supplementing the artefacts in that collection with additional information available either from databases at the artefact's home or from the Web at large, and (c) providing an interaction paradigm that will support effective exploration of this new resource. We describe how we used two available frameworks, mSpace and EPrints to support this kind of collection building. The result of the study is a set of recommendations to improve the connectivity of remote resources both to one another and to related Web resources, and that will also reduce problems like co-referencing in order to enable the creation of new collections on demand
The complexity of approximating the matching polynomial in the complex plane
We study the problem of approximating the value of the matching polynomial on
graphs with edge parameter , where takes arbitrary values in
the complex plane.
When is a positive real, Jerrum and Sinclair showed that the problem
admits an FPRAS on general graphs. For general complex values of ,
Patel and Regts, building on methods developed by Barvinok, showed that the
problem admits an FPTAS on graphs of maximum degree as long as
is not a negative real number less than or equal to
. Our first main result completes the picture for the
approximability of the matching polynomial on bounded degree graphs. We show
that for all and all real less than ,
the problem of approximating the value of the matching polynomial on graphs of
maximum degree with edge parameter is #P-hard.
We then explore whether the maximum degree parameter can be replaced by the
connective constant. Sinclair et al. showed that for positive real it
is possible to approximate the value of the matching polynomial using a
correlation decay algorithm on graphs with bounded connective constant (and
potentially unbounded maximum degree). We first show that this result does not
extend in general in the complex plane; in particular, the problem is #P-hard
on graphs with bounded connective constant for a dense set of values
on the negative real axis. Nevertheless, we show that the result does extend
for any complex value that does not lie on the negative real axis. Our
analysis accounts for complex values of using geodesic distances in
the complex plane in the metric defined by an appropriate density function
Inapproximability of the independent set polynomial in the complex plane
We study the complexity of approximating the independent set polynomial
of a graph with maximum degree when the activity
is a complex number.
This problem is already well understood when is real using
connections to the -regular tree . The key concept in that case is
the "occupation ratio" of the tree . This ratio is the contribution to
from independent sets containing the root of the tree, divided
by itself. If is such that the occupation ratio
converges to a limit, as the height of grows, then there is an FPTAS for
approximating on a graph with maximum degree .
Otherwise, the approximation problem is NP-hard.
Unsurprisingly, the case where is complex is more challenging.
Peters and Regts identified the complex values of for which the
occupation ratio of the -regular tree converges. These values carve a
cardioid-shaped region in the complex plane. Motivated by the
picture in the real case, they asked whether marks the true
approximability threshold for general complex values .
Our main result shows that for every outside of ,
the problem of approximating on graphs with maximum degree
at most is indeed NP-hard. In fact, when is outside of
and is not a positive real number, we give the stronger result
that approximating is actually #P-hard. If is a
negative real number outside of , we show that it is #P-hard to
even decide whether , resolving in the affirmative a conjecture
of Harvey, Srivastava and Vondrak.
Our proof techniques are based around tools from complex analysis -
specifically the study of iterative multivariate rational maps
Constructing the Cool Wall: A Tool to Explore Teen Meanings of Cool
This paper describes the development and exploration of a tool designed to assist in investigating âcoolâ as it applies to the design of interactive products for teenagers. The method involved the derivation of theoretical understandings of cool from literature that resulted in identification of seven core categories for cool, which were mapped to a hierarchy. The hierarchy includes having of cool things, the doing of cool activities and the being of cool. This paper focuses on a tool, the Cool Wall, developed to explore one specific facet of the hierarchy; exploring shared understanding of having cool things. The paper describes the development and construction of the tool, using a heavily participatory approach, and the results and analysis of a study carried out over 2 days in a school in the UK. The results of the study both provide clear insights into cool things and enable a refined understanding of cool in this context. Two additional studies are then used to identify potential shortcomings in the Cool Wall methodology. In the first study participants were able to populate a paper cool wall with anything they chose, this revealed two potential new categories of images and that the current set of images covered the majority of key themes. In the second study teenagers interpretations of the meaning of the images included in the Cool Wall were explored, this showed that the majority of meanings were as expected and a small number of unexpected interpretations provided some valuable insights
TLA+ Proofs
TLA+ is a specification language based on standard set theory and temporal
logic that has constructs for hierarchical proofs. We describe how to write
TLA+ proofs and check them with TLAPS, the TLA+ Proof System. We use Peterson's
mutual exclusion algorithm as a simple example to describe the features of
TLAPS and show how it and the Toolbox (an IDE for TLA+) help users to manage
large, complex proofs.Comment: A shorter version of this article appeared in the proceedings of the
conference Formal Methods 2012 (FM 2012, Paris, France, Springer LNCS 7436,
pp. 147-154
An examination of the process of role change at end of life in a contemporary, regional Australian context
Daniel Lowrie examined the process of role change at end of life in contemporary Australia. He identified problems with role confusion and role relations mismatch, particularly during the protracted middle phase of dying. His findings highlight the need for better support for dying persons and their caregivers during this time
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