6,287 research outputs found
Strategies for Parallel Markup
Cross-referenced parallel markup for mathematics allows the combination of
both presentation and content representations while associating the components
of each. Interesting applications are enabled by such an arrangement, such as
interaction with parts of the presentation to manipulate and querying the
corresponding content, and enhanced search indexing. Although the idea of such
markup is hardly new, effective techniques for creating and manipulating it are
more difficult than it appears. Since the structures and tokens in the two
formats often do not correspond one-to-one, decisions and heuristics must be
developed to determine in which way each component refers to and is referred to
by components of the other representation. Conversion between fine and coarse
grained parallel markup complicates ID assignments. In this paper, we will
describe the techniques developed for \LaTeXML, a \TeX/\LaTeX to XML converter,
to create cross-referenced parallel MathML. While we do not yet consider
\LaTeXML's content MathML to be useful, the current effort is a step towards
that continuing goal
Intramitochondrial sorting of the precursor to yeast cytochrome c oxidase subunit Va.
We have continued our studies on the import pathway of the precursor to yeast cytochrome c oxidase subunit Va (pVa), a mitochondrial inner membrane protein. Previous work on this precursor demonstrated that import of pVa is unusually efficient, and that inner membrane localization is directed by a membrane-spanning domain in the COOH-terminal third of the protein. Here we report the results of studies aimed at analyzing the intramitochondrial sorting of pVa, as well as the role played by ancillary factors in import and localization of the precursor. We found that pVa was efficiently imported and correctly sorted in mitochondria prepared from yeast strains defective in the function of either mitochondrial heat shock protein (hsp)60 or hsp70. Under identical conditions the import and sorting of another mitochondrial protein, the precursor to the beta subunit of the F1 ATPase, was completely defective. Consistent with previous results demonstrating that the subunit Va precursor is loosely folded, we found that pVa could be efficiently imported into mitochondria after translation in wheat germ extracts. This results suggests that normal levels of extramitochondrial hsp70 are also not required for import of the protein. The results of this study enhance our understanding of the mechanism by which pVa is routed to the mitochondrial inner membrane. They suggest that while the NH2 terminus of pVa is exposed to the matrix and processed by the matrix metalloprotease, the protein remains anchored to the inner membrane before being assembled into a functional holoenzyme complex
A Survey on Retrieval of Mathematical Knowledge
We present a short survey of the literature on indexing and retrieval of
mathematical knowledge, with pointers to 72 papers and tentative taxonomies of
both retrieval problems and recurring techniques.Comment: CICM 2015, 20 page
VMEXT: A Visualization Tool for Mathematical Expression Trees
Mathematical expressions can be represented as a tree consisting of terminal
symbols, such as identifiers or numbers (leaf nodes), and functions or
operators (non-leaf nodes). Expression trees are an important mechanism for
storing and processing mathematical expressions as well as the most frequently
used visualization of the structure of mathematical expressions. Typically,
researchers and practitioners manually visualize expression trees using
general-purpose tools. This approach is laborious, redundant, and error-prone.
Manual visualizations represent a user's notion of what the markup of an
expression should be, but not necessarily what the actual markup is. This paper
presents VMEXT - a free and open source tool to directly visualize expression
trees from parallel MathML. VMEXT simultaneously visualizes the presentation
elements and the semantic structure of mathematical expressions to enable users
to quickly spot deficiencies in the Content MathML markup that does not affect
the presentation of the expression. Identifying such discrepancies previously
required reading the verbose and complex MathML markup. VMEXT also allows one
to visualize similar and identical elements of two expressions. Visualizing
expression similarity can support support developers in designing retrieval
approaches and enable improved interaction concepts for users of mathematical
information retrieval systems. We demonstrate VMEXT's visualizations in two
web-based applications. The first application presents the visualizations
alone. The second application shows a possible integration of the
visualizations in systems for mathematical knowledge management and
mathematical information retrieval. The application converts LaTeX input to
parallel MathML, computes basic similarity measures for mathematical
expressions, and visualizes the results using VMEXT.Comment: 15 pages, 4 figures, Intelligent Computer Mathematics - 10th
International Conference CICM 2017, Edinburgh, UK, July 17-21, 2017,
Proceeding
Revealing the timing of ocean stratification using remotely sensed ocean fronts
Stratification is of critical importance to the circulation, mixing and productivity of the ocean, and is expected to be modified by climate change. Stratification is also understood to affect the surface aggregation of pelagic fish and hence the foraging behaviour and distribution of their predators such as seabirds and cetaceans. Hence it would be prudent to monitor the stratification of the global ocean, though this is currently only possible using in situ sampling, profiling buoys or underwater autonomous vehicles. Earth observation (EO) sensors cannot directly detect stratification, but can observe surface features related to the presence of stratification, for example shelf-sea fronts that separate tidally-mixed water from seasonally stratified water. This paper describes a novel algorithm that accumulates evidence for stratification from a sequence of oceanic front maps, and discusses preliminary results in comparison with in situ data and simulations from 3D hydrodynamic models. In certain regions, this method can reveal the timing of the seasonal onset and breakdown of stratification
The imprints of AGN feedback within a supermassive black hole's sphere of influence
We present a new 300 ks Chandra observation of M87 that limits pileup to only
a few per cent of photon events and maps the hot gas properties closer to the
nucleus than has previously been possible. Within the supermassive black hole's
gravitational sphere of influence, the hot gas is multiphase and spans
temperatures from 0.2 to 1 keV. The radiative cooling time of the lowest
temperature gas drops to only 0.1-0.5 Myr, which is comparable to its free fall
time. Whilst the temperature structure is remarkably symmetric about the
nucleus, the density gradient is steep in sectors to the N and S, with
, and significantly shallower along the jet axis
to the E, where . The density structure within
the Bondi radius is therefore consistent with steady inflows perpendicular to
the jet axis and an outflow directed E along the jet axis. By putting limits on
the radial flow speed, we rule out Bondi accretion on the scale resolved at the
Bondi radius. We show that deprojected spectra extracted within the Bondi
radius can be equivalently fit with only a single cooling flow model, where gas
cools from 1.5 keV down below 0.1 keV at a rate of 0.03 M/yr. For the
alternative multi-temperature spectral fits, the emission measures for each
temperature component are also consistent with a cooling flow model. The lowest
temperature and most rapidly cooling gas in M87 is therefore located at the
smallest radii at ~100 pc and may form a mini cooling flow. If this cooling gas
has some angular momentum, it will feed into the cold gas disk around the
nucleus, which has a radius of ~80 pc and therefore lies just inside the
observed transition in the hot gas structure
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Comparative environmental life cycle assessment of conventional energy storage system and innovative thermal energy storage system
© 2021 The Author(s). As policies have been implemented globally to limit the production of greenhouse gases (GHGs) and the effects of climate change, the generation of electricity by renewable technologies has started to increase. The development of sustainable energy storage solutions has also become more important. The continued use of conventional chemical batteries presents environmental issues such as heavy metal pollution and the use of unsustainable resources.
An environmental Life Cycle Assessment (LCA) has been conducted to analyse the environmental impact of an innovative Thermal Battery (TB) and was compared with the impact of a Lithium Iron Phosphate Battery (LIPB) using a “cradle-to-gate” approach to establish the system boundaries. The study used the findings from existing literature to determine the environmental impact of the LIPB. The life cycle inventory for the TB was constructed based on a model and available literature. In this regard, the two products were compared on 10 impact categories, and the results indicated that the TB performed better in 8 categories on average. The highest impact observed from the TB was in terrestrial ecotoxicity, where it emitted above 7000 times more than the LIPB, amounting to approximately 0.0153 after normalisation. The highest normalised environmental load in the study was indicated to be in the category of marine ecotoxicity by the LIPB at 0.27, which was significantly higher than any load for the TB. Overall, the results obtained are encouraging for the TB, but it is recommended that a field study is completed to verify the assumptions made in this paper and to achieve a better comparability with studies conducted similarly.Spirax Sarco Engineering PLC
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