497 research outputs found
A bibliometric study of the research field of experimental philosophy of language
The past eighteen years witnessed the rapid development of experimental philosophy of language. Adopting a bibliometric approach, this study examines the research trends and status quo of this burgeoning field based on a corpus of 237 publications retrieved from PhilPapers. It is observed that experimental philosophy of language has undergone three stages, the initiation stage, the development stage, and the extension stage, across which there is a clear upward trend in the annual number of publications. Michael Devitt, Edouard Machery, John Turri, Nat Hansen, et al., are found to be the most productive philosophers, testifying their leading positions in this field. Journals, instead of books, are the major homes of works in this area. The analysis also yields a list of influential works, including the seminal work “Semantics, Cross-cultural Style” and other significant publications on the semantics of various types of expressions. Relatedly, the major research themes are found to include not only intuitions about the reference of proper names, but also a wide array of philosophically and linguistically interesting issues like the meaning of color adjectives, epistemic modals, and predicates of personal taste, the norms of assertions and the essence of lies, etc. These findings showcase that experimental philosophy of language has broadened the research territory and offered deep insights into central issues of philosophy of language that are beyond the reach of the conventional armchair methodology
Multilingual Text Detection with Nonlinear Neural Network
Multilingual text detection in natural scenes is still a challenging task in computer vision. In this paper, we apply an unsupervised learning algorithm to learn language-independent stroke feature and combine unsupervised stroke feature learning and automatically multilayer feature extraction to improve the representational power of text feature. We also develop a novel nonlinear network based on traditional Convolutional Neural Network that is able to detect multilingual text regions in the images. The proposed method is evaluated on standard benchmarks and multilingual dataset and demonstrates improvement over the previous work
Molecular Dynamics Simulation of Macromolecules Using Graphics Processing Unit
Molecular dynamics (MD) simulation is a powerful computational tool to study
the behavior of macromolecular systems. But many simulations of this field are
limited in spatial or temporal scale by the available computational resource.
In recent years, graphics processing unit (GPU) provides unprecedented
computational power for scientific applications. Many MD algorithms suit with
the multithread nature of GPU. In this paper, MD algorithms for macromolecular
systems that run entirely on GPU are presented. Compared to the MD simulation
with free software GROMACS on a single CPU core, our codes achieve about 10
times speed-up on a single GPU. For validation, we have performed MD
simulations of polymer crystallization on GPU, and the results observed
perfectly agree with computations on CPU. Therefore, our single GPU codes have
already provided an inexpensive alternative for macromolecular simulations on
traditional CPU clusters and they can also be used as a basis to develop
parallel GPU programs to further speedup the computations.Comment: 21 pages, 16 figure
Study of neurodegenerative diseases with novel MRI techniques
Neurodegenerative diseases are a heterogeneous group of disorders that are
characterized by the progressive degeneration of structure and function of the nervous
system. They include diseases such as Alzheimer’s disease (AD), multiple sclerosis
(MS) and others. The main aims of this thesis were to study functional and/or
structural brain changes in AD and MS using novel magnetic resonance imaging
(MRI) techniques.
The concentration of β-amyloid1-42 (Aβ42), total tau (T-tau) and tau phosphorylated at
position threonine 181 (P-tau181p) in cerebrospinal fluid (CSF) may reflect brain
pathophysiological processes in AD. We found a positive correlation between
functional connectivity within the default mode network (DMN) and the ratio of
Aβ42/P-tau181p in sporadic AD (Paper I). Furthermore, there were correlations
between AD CSF biomarkers and changes of gray matter volume, fractional
anisotropy (FA) and mean diffusivity (MD). The majority of brain regions with
statistically significant correlation with biomarkers of AD overlapped with the DMN
(Paper II). These findings implicate that the brain functional connectivity and
structure are affected by pathological changes at an early stage in AD. We also found
a significantly increased MD in pre-symptomatic mutation carriers (pre-MCs) of AD
compared with non-carriers (NCs), and increased MD associated with AD CSF
biomarkers (Paper III). Similar results were observed both in sporadic and familial
AD, which suggests that MD may reflect pathology of early stage AD. Although the
exact causes of these changes are difficult to identify, the increased MD may be
explained by myelin loss. In MS, myelin loss is one of the characteristic events of
the pathological process. By combining susceptibility-weighted MRI with analysis of
the !
∗ decay curves, we were able to characterize and quantify myelin loss (Paper
IV).
In conclusion, pathological changes in AD and MS could be detected by novel MRI
techniques. This suggests that these techniques may also be helpful in further
understanding pathology in other neurodegenerative diseases. As non-invasive tools,
these novel MRI techniques are possible to screen individuals susceptible to and/or
manifesting early neurodegeneration
Investigation of nonlinear flame response to dual-frequency disturbances
The two-way interaction between the unsteady flame heat release rate and
acoustic waves can lead to combustion instability within combustors. To
understand and quantify the flame response to oncoming acoustic waves, previous
studies have typically considered the flame dynamic response to pure tone
forcing and assumed a dynamically linear or weakly nonlinear response. In this
study, the introduction of excitation with two distinct frequencies denoted
and is considered, including the effect of excitation amplitude
in order to gain more insight into the nature of flame nonlinearities and these
associated with combustion instabilities. Corresponding results are obtained by
combining a low-order asymptotic analysis (up to third order in normalised
excitation amplitude) with numerical methods based on the model framework of
the -equation. The influence paths of the disturbance at on the flame
dynamic response at are studied in detail. Due to the flame propagating
forward normally to itself (named flame kinematic restoration), the
perturbation at acts together with that at to induce a
third-order nonlinear interaction in the flame kinematics, impressively
suppressing the spatial wrinkling of the flame at . Additionally,
introducing the perturbation at alters the effective flame displacement
speed, which is responsible for the calculation of the flame heat release rate
and further affects the global response at . Taking into account the
above two factors, the nonlinear response of the flame at is completely
quantified and the corresponding characteristics are clearly interpreted
jaw-1D: a gain-of-function mutation responsive to paramutation-like induction of epigenetic silencing
The Arabidopsis thaliana gain-of-function T-DNA insertion mutant jaw-1D produces miR319A, a microRNA that represses genes encoding CIN-like TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTORs (TCPs), a family of transcription factors that play key roles in leaf morphogenesis. In this study, we show that jaw-1D is responsive to paramutation-like epigenetic silencing. A genetic cross of jaw-1D with the polycomb gene mutant curly leaf-29 (clf-29) leads to attenuation of the jaw-1D mutant plant phenotype. This induced mutation, jaw-1D*, was associated with down-regulation of miR319A, was heritable independently from clf-29, and displayed paramutation-like non-Mendelian inheritance. Down-regulation of miR319A in jaw-1D* was linked to elevated levels of histone H3 lysine 9 dimethylation and DNA methylation at the CaMV35S enhancer located within the activation-tagging T-DNA of the jaw-1D locus. Examination of 21 independent T-DNA insertion mutant lines revealed that 11 could attenuate the jaw-1D mutant phenotype in a similar way to the paramutation induced by clf-29. These paramutagenic mutant lines shared the common feature that their T-DNA insertion was present as multi-copy tandem repeats and contained high levels of CG and CHG methylation. Our results provide important insights into paramutation-like epigenetic silencing, and caution against the use of jaw-1D in genetic interaction studies
A Novel System Anomaly Prediction System Based on Belief Markov Model and Ensemble Classification
Computer systems are becoming extremely complex, while system anomalies dramatically influence the availability and usability of systems. Online anomaly prediction is an important approach to manage imminent anomalies, and the high accuracy relies on precise system monitoring data. However, precise monitoring data is not easily achievable because of widespread noise. In this paper, we present a method which integrates an improved Evidential Markov model and ensemble classification to predict anomaly for systems with noise. Traditional Markov models use explicit state boundaries to build the Markov chain and then make prediction of different measurement metrics. A Problem arises when data comes with noise because even slight oscillation around the true value will lead to very different predictions. Evidential Markov chain method is able to deal with noisy data but is not suitable in complex data stream scenario. The Belief Markov chain that we propose has extended Evidential Markov chain and can cope with noisy data stream. This study further applies ensemble classification to identify system anomaly based on the predicted metrics. Extensive experiments on anomaly data collected from 66 metrics in PlanetLab have confirmed that our approach can achieve high prediction accuracy and time efficiency
Shading Reduced the Injury Caused by Winter Chill on Pitaya Plant
Pitaya (Hylocereus undatus Britton & Rose) is widely cultivated in subtropical and tropical regions. Pitaya is cold-sensitive; most cultivars are injured during chilling winter periods, especially in subtropical regions. In this study, the effects of shading on the cold tolerance in pitaya plant were investigated. Pitaya plants were grown under full sunlight (control) or a shading net with a light blocking rate of about 60%. Morphological and physiological performance of the overwintering pitaya plants were compared between the control and the shaded treatment. The results showed that shading treatment markedly reduced the chilling induced tissue necrosis. Contents of chlorophyll a, chlorophyll b, and total chlorophylls (chlorophyll a+b), the chlorophyll a/b ratio, Fm and Fv/Fm were all higher in shading treatment than those in the control. Meanwhile, proline content and ascorbic acid peroxidase (APX) activity in the shading treatment were significantly increased, while malondialdehyde (MDA), the superoxide anion (O2.-) and hydrogen peroxide (H2O2) levels were significantly decreased by shading treatment. The results indicated that damage caused by chilling stress on pitaya was, at least partially, light-dependent; and in practical production, shading treatment can be used to reduce chilling injury in pitaya
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