1,009 research outputs found
Chinese Discourse Annotation Reference Manual
This document provides extensive guidelines and examples for Rhetorical
Structure Theory (RST) annotation in Mandarin Chinese. The guideline is divided
into three sections. We first introduce preprocessing steps to prepare data for
RST annotation. Secondly, we discuss syntactic criteria to segment texts into
Elementary Discourse Units (EDUs). Lastly, we provide examples to define and
distinguish discourse relations in different genres. We hope that this
reference manual can facilitate RST annotations in Chinese and accelerate the
development of the RST framework across languages
What's Hard in English RST Parsing? Predictive Models for Error Analysis
Despite recent advances in Natural Language Processing (NLP), hierarchical
discourse parsing in the framework of Rhetorical Structure Theory remains
challenging, and our understanding of the reasons for this are as yet limited.
In this paper, we examine and model some of the factors associated with parsing
difficulties in previous work: the existence of implicit discourse relations,
challenges in identifying long-distance relations, out-of-vocabulary items, and
more. In order to assess the relative importance of these variables, we also
release two annotated English test-sets with explicit correct and distracting
discourse markers associated with gold standard RST relations. Our results show
that as in shallow discourse parsing, the explicit/implicit distinction plays a
role, but that long-distance dependencies are the main challenge, while lack of
lexical overlap is less of a problem, at least for in-domain parsing. Our final
model is able to predict where errors will occur with an accuracy of 76.3% for
the bottom-up parser and 76.6% for the top-down parser.Comment: SIGDIAL 2023 camera-ready; 12 page
Sun-to-Earth Characteristics of Two Coronal Mass Ejections Interacting near 1 AU: Formation of a Complex Ejecta and Generation of a Two-Step Geomagnetic Storm
On 2012 September 30 - October 1 the Earth underwent a two-step geomagnetic
storm. We examine the Sun-to-Earth characteristics of the coronal mass
ejections (CMEs) responsible for the geomagnetic storm with combined
heliospheric imaging and in situ observations. The first CME, which occurred on
2012 September 25, is a slow event and shows an acceleration followed by a
nearly invariant speed in the whole Sun-Earth space. The second event, launched
from the Sun on 2012 September 27, exhibits a quick acceleration, then a rapid
deceleration and finally a nearly constant speed, a typical Sun-to-Earth
propagation profile for fast CMEs \citep{liu13}. These two CMEs interacted near
1 AU as predicted by the heliospheric imaging observations and formed a complex
ejecta observed at Wind, with a shock inside that enhanced the pre-existing
southward magnetic field. Reconstruction of the complex ejecta with the in situ
data indicates an overall left-handed flux rope-like configuration, with an
embedded concave-outward shock front, a maximum magnetic field strength
deviating from the flux rope axis and convex-outward field lines ahead of the
shock. While the reconstruction results are consistent with the picture of
CME-CME interactions, a magnetic cloud-like structure without clear signs of
CME interactions \citep{lugaz14} is anticipated when the merging process is
finished.Comment: 15 pages, 5 figures. Accepted for publication in ApJ Letter
On Sun-to-Earth Propagation of Coronal Mass Ejections: 2. Slow Events and Comparison with Others
As a follow-up study on Sun-to-Earth propagation of fast coronal mass
ejections (CMEs), we examine the Sun-to-Earth characteristics of slow CMEs
combining heliospheric imaging and in situ observations. Three events of
particular interest, the 2010 June 16, 2011 March 25 and 2012 September 25
CMEs, are selected for this study. We compare slow CMEs with fast and
intermediate-speed events, and obtain key results complementing the attempt of
\citet{liu13} to create a general picture of CME Sun-to-Earth propagation: (1)
the Sun-to-Earth propagation of a typical slow CME can be approximately
described by two phases, a gradual acceleration out to about 20-30 solar radii,
followed by a nearly invariant speed around the average solar wind level, (2)
comparison between different types of CMEs indicates that faster CMEs tend to
accelerate and decelerate more rapidly and have shorter cessation distances for
the acceleration and deceleration, (3) both intermediate-speed and slow CMEs
would have a speed comparable to the average solar wind level before reaching 1
AU, (4) slow CMEs have a high potential to interact with other solar wind
structures in the Sun-Earth space due to their slow motion, providing critical
ingredients to enhance space weather, and (5) the slow CMEs studied here lack
strong magnetic fields at the Earth but tend to preserve a flux-rope structure
with axis generally perpendicular to the radial direction from the Sun. We also
suggest a "best" strategy for the application of a triangulation concept in
determining CME Sun-to-Earth kinematics, which helps to clarify confusions
about CME geometry assumptions in the triangulation and to improve CME analysis
and observations.Comment: 37 pages, 13 figures, accepted for publication in ApJ Supplemen
Quantitative and functional post-translational modification proteomics reveals that TREPH1 plays a role in plant thigmomorphogenesis
Plants can sense both intracellular and extracellular mechanical forces and
can respond through morphological changes. The signaling components responsible
for mechanotransduction of the touch response are largely unknown. Here, we
performed a high-throughput SILIA (stable isotope labeling in
Arabidopsis)-based quantitative phosphoproteomics analysis to profile changes
in protein phosphorylation resulting from 40 seconds of force stimulation in
Arabidopsis thaliana. Of the 24 touch-responsive phosphopeptides identified,
many were derived from kinases, phosphatases, cytoskeleton proteins, membrane
proteins and ion transporters. TOUCH-REGULATED PHOSPHOPROTEIN1 (TREPH1) and MAP
KINASE KINASE 2 (MKK2) and/or MKK1 became rapidly phosphorylated in
touch-stimulated plants. Both TREPH1 and MKK2 are required for touch-induced
delayed flowering, a major component of thigmomorphogenesis. The treph1-1 and
mkk2 mutants also exhibited defects in touch-inducible gene expression. A
non-phosphorylatable site-specific isoform of TREPH1 (S625A) failed to restore
touch-induced flowering delay of treph1-1, indicating the necessity of S625 for
TREPH1 function and providing evidence consistent with the possible functional
relevance of the touch-regulated TREPH1 phosphorylation. Bioinformatic analysis
and biochemical subcellular fractionation of TREPH1 protein indicate that it is
a soluble protein. Altogether, these findings identify new protein players in
Arabidopsis thigmomorphogenesis regulation, suggesting that protein
phosphorylation may play a critical role in plant force responses
PLASMA AND MAGNETIC FIELD CHARACTERISTICS OF SOLAR CORONAL MASS EJECTIONS IN RELATION TO GEOMAGNETIC STORM INTENSITY AND VARIABILITY
The largest geomagnetic storms of solar cycle 24 so far occurred on 2015 March 17 and June 22 with D[subscript st] minima of -223 and -195 nT, respectively. Both of the geomagnetic storms show a multi-step development. We examine the plasma and magnetic field characteristics of the driving coronal mass ejections (CMEs) in connection with the development of the geomagnetic storms. A particular effort is to reconstruct the in situ structure using a Grad–Shafranov technique and compare the reconstruction results with solar observations, which gives a larger spatial perspective of the source conditions than one-dimensional in situ measurements. Key results are obtained concerning how the plasma and magnetic field characteristics of CMEs control the geomagnetic storm intensity and variability: (1) a sheath-ejecta-ejecta mechanism and a sheath-sheath-ejecta scenario are proposed for the multi-step development of the 2015 March 17 and June 22 geomagnetic storms, respectively; (2) two contrasting cases of how the CME flux-rope characteristics generate intense geomagnetic storms are found, which indicates that a southward flux-rope orientation is not a necessity for a strong geomagnetic storm; and (3) the unexpected 2015 March 17 intense geomagnetic storm resulted from the interaction between two successive CMEs plus the compression by a high-speed stream from behind, which is essentially the "perfect storm" scenario proposed by Liu et al. (i.e., a combination of circumstances results in an event of unusual magnitude), so the "perfect storm" scenario may not be as rare as the phrase implies.China. Recruitment Program of Global ExpertsNational Natural Science Foundation (China) (Grant 41374173)State Key Laboratories of China (Specialized Research Fund
Keeping the rhythm:light/dark cycles during postharvest storage preserve the tissue integrity and nutritional content of leafy plants
Background: The modular body structure of plants enables detached plant organs, such as postharvest fruits and vegetables, to maintain active responsiveness to environmental stimuli, including daily cycles of light and darkness. Twenty-four hour light/darkness cycles entrain plant circadian clock rhythms, which provide advantage to plants. Here, we tested whether green leafy vegetables gain longevity advantage by being stored under light/dark cycles designed to maintain biological rhythms. Results: Light/dark cycles during postharvest storage improved several aspects of plant tissue performance comparable to that provided by refrigeration. Tissue integrity, green coloration, and chlorophyll content were generally enhanced by cycling of light and darkness compared to constant light or darkness during storage. In addition, the levels of the phytonutrient glucosinolates in kale and cabbage remained at higher levels over time when the leaf tissue was stored under light/dark cycles. Conclusions: Maintenance of the daily cycling of light and dark periods during postharvest storage may slow the decline of plant tissues, such as green leafy vegetables, improving not only appearance but also the health value of the crops through the maintenance of chlorophyll and phytochemical content after harvest
RhoGDIβ-induced hypertrophic growth in H9c2 cells is negatively regulated by ZAK
We found that overexpression of RhoGDIβ, a Rho GDP dissociation inhibitor, induced hypertrophic growth and suppressed cell cycle progression in a cultured cardiomyoblast cell line. Knockdown of RhoGDIβ expression by RNA interference blocked hypertrophic growth. We further demonstrated that RhoGDIβ physically interacts with ZAK and is phosphorylated by ZAK in vitro, and this phosphorylation negatively regulates RhoGDIβ functions. Moreover, the ZAK-RhoGDIβ interaction may maintain ZAK in an inactive hypophosphorylated form. These two proteins could negatively regulate one another such that ZAK suppresses RhoGDIβ functions through phosphorylation and RhoGDIβ counteracts the effects of ZAK by physical interaction. Knockdown of ZAK expression in ZAK- and RhoGDIβ-expressing cells by ZAK-specific RNA interference restored the full functions of RhoGDIβ
GENTLE: A Genre-Diverse Multilayer Challenge Set for English NLP and Linguistic Evaluation
We present GENTLE, a new mixed-genre English challenge corpus totaling 17K
tokens and consisting of 8 unusual text types for out-of domain evaluation:
dictionary entries, esports commentaries, legal documents, medical notes,
poetry, mathematical proofs, syllabuses, and threat letters. GENTLE is manually
annotated for a variety of popular NLP tasks, including syntactic dependency
parsing, entity recognition, coreference resolution, and discourse parsing. We
evaluate state-of-the-art NLP systems on GENTLE and find severe degradation for
at least some genres in their performance on all tasks, which indicates
GENTLE's utility as an evaluation dataset for NLP systems.Comment: Camera-ready for LAW-XVII collocated with ACL 202
ZAK negatively regulates RhoGDIβ-induced Rac1-mediated hypertrophic growth and cell migration
RhoGDIβ, a Rho GDP dissociation inhibitor, induced hypertrophic growth and cell migration in a cultured cardiomyoblast cell line, H9c2. We demonstrated that RhoGDIβ plays a previously undefined role in regulating Rac1 expression through transcription to induce hypertrophic growth and cell migration and that these functions are blocked by the expression of a dominant-negative form of Rac1. We also demonstrated that knockdown of RhoGDIβ expression by RNA interference blocked RhoGDIβ-induced Rac1 expression and cell migration. We demonstrated that the co-expression of ZAK and RhoGDIβ in cells resulted in an inhibition in the activity of ZAK to induce ANF expression. Knockdown of ZAK expression in ZAK-RhoGDIβ-expressing cells by ZAK-specific RNA interference restored the activities of RhoGDIβ
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