20,580 research outputs found
So Are We Keynesians or Not?
There is plenty of room for empirical debate with respect to the efficacy of fiscal policy in general, whether monetary policy is a better tool, or what constitutes spending that will make us more productive in the future.Martin Kennedy, Keynes, Keynesianism, ARRA, stimulus, fiscal policy, Tennessee
Bott periodicity for symmetric ground states of gapped free-fermion systems
Building on the symmetry classification of disordered fermions, we give a
proof of the proposal by Kitaev, and others, for a "Bott clock" topological
classification of free-fermion ground states of gapped systems with symmetries.
Our approach differs from previous ones in that (i) we work in the standard
framework of Hermitian quantum mechanics over the complex numbers, (ii) we
directly formulate a mathematical model for ground states rather than
spectrally flattened Hamiltonians, and (iii) we use homotopy-theoretic tools
rather than K-theory. Key to our proof is a natural transformation that squares
to the standard Bott map and relates the ground state of a d-dimensional system
in symmetry class s to the ground state of a (d+1)-dimensional system in
symmetry class s+1. This relation gives a new vantage point on topological
insulators and superconductors.Comment: 55 pages; one figure added; corrections in Section 8; proofs in
Section 6 expande
A New Approach to the Problem of Dynamical Quarks in Numerical Simulations of Lattice QCD
Lattice QCD with an even number of degenerate quark flavours is shown to be a
limit of a local bosonic field theory. The action of the bosonic theory is real
and bounded from below so that standard simulation algorithms can be expected
to apply. The feasibility of such calculations is discussed, but no practical
tests have yet been made.Comment: pages 0-15, ps-file 147KB, preprint DESY 93-14
Arkansas Cotton Variety Test 2013
The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant. These annual evaluations will then facilitate the inclusion of new, improved genetic material in Arkansas cotton production
A Biological Comparison of Two Sites: an Ecological Approach Using Community Ecology Metrics Based on Insect Faunal Composition
Two natural sites in the Portland urban area, River View Natural Area (RVNA) and Powers Marine Park (PMP), were sampled to assess their insect faunal composition with the intention of determining whether the areas are sufficiently similar ecologically that they could potentially be managed as a single unit. The two areas were compared using community ecology metrics based on their respective invertebrate fauna. The results suggested that RVNA and PMP had statistically different ecological communities. The Shannon Diversity Index for PMP was 0.303, and 0.819 for RVNA. The Horn Index of Community Overlap suggested a 93.46% overlap based on these data; however, a Hutcheson’s t-test for community ecology data suggested significant differences (P \u3c\u3c\u3c 0.0001) between PMP and RVNA’s insect faunal compositions
Recommended from our members
A Framework for the Systematic Evaluation of Malware Forensic Tools
Following a series of high profile miscarriages of justice linked to questionable expert evidence, the post of the Forensic Science Regulator was created in 2008 with a remit to improve the standard of practitioner competences and forensic procedures. It has since moved to incorporate a greater level of scientific practice in these areas, as used in the production of expert evidence submitted to the UK Criminal Justice System. Accreditation to their codes of practice and conduct will become mandatory for all forensic practitioners by October 2017. A variety of challenges with expert evidence are explored and linked to a lack of a scientific methodology underpinning the processes followed. In particular, the research focuses upon investigations where malicious software (‘malware’) has been identified.
A framework, called the ‘Malware Analysis Tool Evaluation Framework’ (MATEF), has been developed to address this lack of methodology to evaluate software tools used during investigations involving malware. A prototype implementation of the framework was used to evaluate two tools against a population of over 350,000 samples of malware. Analysis of the findings indicated that the choice of tool could impact on the number of artefacts observed in malware forensic investigations as well as identifying the optimal execution time for a given tool when observing malware artefacts.
Three different measures were used to evaluate the framework. The first of these evaluated the framework against the requirements and determined that these were largely met. Where the requirements were not met these are attributed to matters either outside scope or the fledgling nature of the research. Another measure used to evaluate the framework was to consider its performance in terms of speed and resource utilisation. This identified scope for improvement in terms of the time to complete a test and the need for more economical use of disk space. Finally, the framework provides a scientific means to evaluate malware analysis tools, hence addressing the Research Question subject to the level at which ground truth is established.
A number of contributions are produced as the output of this work. First there is confirmation for the case for a lack of trusted practice in the field of malware forensics. Second, the MATEF itself, as it facilitates the production of empirical evidence of a tool’s ability to detect malware artefacts. A third contribution is a set of requirements for establishing trusted practice in the use of malware artefact detection tools. Finally, empirical evidence that supports both the notion that the choice of tool can impact on the number of artefacts observed in malware forensic investigations as well as identifying the optimal execution time for a given tool when observing malware artefacts
Factors Affecting Adoption of Quality Assurance in Australian Redmeat Industries
Livestock Production/Industries,
- …