460 research outputs found
Structure of Higher Spin Gauge Interactions
In a previous paper, higher spin gauge field theory was formulated in an
abstract way, essentially only keeping enough machinery to discuss "gauge
invariance" of an "action". The approach could be thought of as providing an
interface (or syntax) towards an implementation (or semantics) yet to be
constructed. The structure then revealed turns out to be that of a strongly
homotopy Lie algebra.
In the present paper, the framework will be connected to more conventional
field theoretic concepts. The Fock complex vertex operator implementation of
the interactions in the BRST-BV formulation of the theory will be elaborated.
The relation between the vertex order expansion and homological perturbation
theory will be clarified. A formal non-obstruction argument is reviewed. The
syntactically derived sh-Lie algebra structure is semantically mapped to the
Fock complex implementation and it is shown that the recursive equations
governing the higher order vertices are reproduced.
Global symmetries and subsidiary conditions are discussed and as a result the
tracelessness constraints are discarded. Thus all equations needed to compute
the vertices to any order are collected. The framework is general enough to
encompass all possible interaction terms.
Finally, the abstract framework itself will be strengthened by showing that
it can be naturally phrased in terms of the theory of categories.Comment: A few changes and additions made in the Introduction. Three
references added. Typos corrected. Text agrees with published version in J.
Math. Phys. except for minor journal specific proof-reading changes. 61 page
A Corpus of Potentially Contradictory Research Claims from Cardiovascular Research Abstracts
Background: Research literature in biomedicine and related fields contains a huge number
of claims, such as the effectiveness of treatments. These claims are not always consistent and
may even contradict each other. Being able to identify contradictory claims is important for
those who rely on the biomedical literature. Automated methods to identify and resolve them
are required to cope with the amount of information available. However, research in this area
has been hampered by a lack of suitable resources. We describe a methodology to develop a
corpus which addresses this gap by providing examples of potentially contradictory claims and
demonstrate how it can be applied to identify these claims from Medline abstracts related to the
topic of cardiovascular disease.
Methods A set of systematic reviews concerned with four topics in cardiovascular disease were
identified from Medline and analysed to determine whether the abstracts they reviewed contained
contradictory research claims. For each review, annotators were asked to analyse these abstracts
to identify claims within them that answered the question addressed in the review. The annotators
were also asked to indicate how the claim related to that question and the type of the claim.
Results: A total of 259 abstracts associated with 24 systematic reviews were used to form
the corpus. Agreement between the annotators was high, suggesting that the information they
provided is reliable.
Conclusions: The paper describes a methodology for constructing a corpus containing contradictory
research claims from the biomedical literature. The corpus is made available to enable
further research into this area and support the development of automated approaches to contradiction
identification
Yield gains in extra-early maize cultivars of three breeding eras under multiple environments
Open Access JournalAvailability of extra-early maize cultivars has facilitated the expansion of maize production into savannas of West and Central Africa (WCA). Fifty-six extra-early maize cultivars of three breeding eras;1995 to 2000, 2001 to 2006, and 2007 to 2012 were evaluated for 2 yr under 24 multiple-stress and 28 non-stress environments in WCA. Objectives of the study were to determine genetic improvement in grain yield of cultivars developed during the breeding eras, and identify high-yielding and s multiple-stress and non-stress environments. Yield gains from era 1 to era 3 under multiple stresses was associated with increased days to anthesis, reduced stalk lodging, and improved husk cover. Cultivars 2004 TZEE-Y Pop STR C4, TZEE-W Pop STR QPM C0, and TZEE-W Pop STR BC2 C0 of era 2; and TZEE-W STR 107 BC1, TZEE-W Pop STR C5, and 2012 TZEE-Y DT STR C5 of era 3 were high-yielding and stable across multiple-stress environments while 98 Syn EE-W from era 1, FERKE TZEE-W STR, TZEE-W Pop STR C3, and TZEE-Y Pop STR QPM C0 from era 2, and TZEE-W Pop STR C5, 2009 TZEE-OR2 STR QPM, 2009 TZEE-W STR, TZEE-Y STR 106, and TZEE-W DT C0 STR C5 from era 3 were outstanding across non-stress environments and should be tested extensively and commercialized. Considerable improvement has been made in breeding for multiple-stress tolerant extra-early maize cultivars
Microscale distribution patterns of terrestrial bryophytes in a subalpine forest: the use of logistic regression as an interpretive tool
This study investigated microhabitat relationships of terrestrial bryophytes in a subalpine forest of coastal British Columbia. Substratum affinities were characterized for dominant bryophytes. Logistic regression analysis was used to gain insight into the ecological determinants of fine scale (0.1 m2) bryophyte distribution by examining the predictive relationship between bryophyte species occurrence and localized environmental conditions, as well as the coverage of other bryophytes. The predictive relationships were compared to evaluate the relative importance of environmental factors versus interspecific interactions in structuring bryophyte communities. The results indicate that bryophytes show unique responses in their relationships to environmental conditions and other bryophytes. Positive feedback appears to be an important process among terrestrial bryophytes in subalpine forests
Diversity and structure of Ephemeroptera, Plecoptera and Trichoptera (Insecta) assemblages from riffles in mountain streams of Central Brazil
Habitat partitioning, habits and convergence among coastal nektonic fish species from the São Sebastião Channel, southeastern Brazil
Composition and seasonal variation of the ichthyofauna from upper Rio Paraguaçu (Chapada Diamantina, Bahia, Brazil)
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