178 research outputs found
A corpus study of verbal multiword expressions in Brazilian Portuguese
Verbal multiword expressions (VMWEs) such as to make ends meet require special attention in NLP and linguistic research, and annotated corpora are valuable resources for studying them. Corpora annotated with VMWEs in several languages, including Brazilian Portuguese, were made freely available in the PARSEME shared task. The goal of this paper is to describe and analyze this corpus in terms of the characteristics of annotated VMWEs in Brazilian Portuguese. First, we summarize and exemplify the criteria used to annotate VMWEs. Then, we analyze their frequency, average length, discontinuities and variability. We further discuss challenging constructions and borderline cases. We believe that this analysis can improve the annotated corpus and its results can be used to develop systems for automatic VMWE identification
Causality detection and turbulence in fusion plasmas
This work explores the potential of an information-theoretical causality
detection method for unraveling the relation between fluctuating variables in
complex nonlinear systems. The method is tested on some simple though nonlinear
models, and guidelines for the choice of analysis parameters are established.
Then, measurements from magnetically confined fusion plasmas are analyzed. The
selected data bear relevance to the all-important spontaneous confinement
transitions often observed in fusion plasmas, fundamental for the design of an
economically attractive fusion reactor. It is shown how the present method is
capable of clarifying the interaction between fluctuating quantities such as
the turbulence amplitude, turbulent flux, and Zonal Flow amplitude, and
uncovers several interactions that were missed by traditional methods.Comment: 26 pages, 14 figure
The molecular basis, genetic control and pleiotropic effects of local gene co-expression.
Nearby genes are often expressed as a group. Yet, the prevalence, molecular mechanisms and genetic control of local gene co-expression are far from being understood. Here, by leveraging gene expression measurements across 49 human tissues and hundreds of individuals, we find that local gene co-expression occurs in 13% to 53% of genes per tissue. By integrating various molecular assays (e.g. ChIP-seq and Hi-C), we estimate the ability of several mechanisms, such as enhancer-gene interactions, in distinguishing gene pairs that are co-expressed from those that are not. Notably, we identify 32,636 expression quantitative trait loci (eQTLs) which associate with co-expressed gene pairs and often overlap enhancer regions. Due to affecting several genes, these eQTLs are more often associated with multiple human traits than other eQTLs. Our study paves the way to comprehend trait pleiotropy and functional interpretation of QTL and GWAS findings. All local gene co-expression identified here is available through a public database ( https://glcoex.unil.ch/ )
Validation of GBS plasma turbulence simulation of the TJ-K stellarator
We present a validation of a three-dimensional, two-fluid simulation of
plasma turbulence in the TJ-K stellarator, a low temperature plasma experiment
ideally suited for turbulence measurements. The simulation is carried out by
the GBS code, recently adapted to simulate 3D magnetic fields. The comparison
shows that GBS retrieves the main turbulence properties observed in the device,
namely the fact that transport is dominated by fluctuations with low poloidal
mode number. The poloidal dependence of the radial
turbulent flux is compared on a poloidal plane with elliptical flux surfaces,
where a very good agreement between experiment and simulation is observed, and
on another with triangular flux surfaces, which shows a poorer comparison. The
fluctuation levels in both cases are underestimated in the simulations. The
equilibrium density profile is well retrieved by the simulation, while the
electron temperature and the electrostatic potential profiles, which are very
sensitive to the strength and localization of the sources, do not agree well
with the experimental measurements
Observation of exponential spectra and Lorentzian pulses in the TJ-K stellarator
An experimental investigation of the low-frequency density fluctuations in the plasma edge region of the TJ-K stellarator [N. Krause et al., Rev. Sci. Inst. 73, 3474 (2002)] finds that the ensemble- averaged frequency spectra exhibit a near exponential frequency dependence whose origin can be traced to individual pulses having a Lorentzian temporal shape. Similar features have been previously observed [D. C. Pace et al., Phys. Plasmas 15, 122304 (2008)] in a linear magnetized device under conditions in which cross-field pressure gradients are present. The reported observation of such features within the turbulent environment of a toroidal confinement device provides support for the conjecture that the underlying processes are a general feature of pressure gradients. Also presented is the magnetic field strength dependence of the pulse widths and the waiting time distribution between pulses
Indicators of soil quality: a South-South development of a methdological guide for linking local and technical knowledge
The increasing attention paid to local soil knowledge results from a greater recognition that farmer knowledge can offer many insights into the sustainable management of tropical soils and that the integration of local and technical knowledge systems helps extension workers and scientists work more closely with farmers. A participatory approach and a methodological guide were developed to identify and classify local indicators of soil quality and relate them to technical soil parameters, and thus develop a common language between farmers, extension workers and scientists. This methodological guide was initially developed and used in Latin America and the Caribbean-LAC (Honduras, Nicaragua, Colombia, Peru, Venezuela, Dominican Republic), and was later improved during adaptation and use in eastern African (Uganda, Tanzania, Kenya, Ethiopia) through a South–South exchange of expertise and experiences. The aim of the methodological guide is to constitute an initial step in the empowerment of local communities to develop a local soil quality monitoring and decision-making system for better management of soil resources. This approach uses consensus building to develop practical solutions to soil management constraints identified, as well as to monitor the impact of management strategies implemented to address these constraints. The particular focus on local and technical indicators of agroecosystem change is useful for providing farmers with early warnings about unobservable changes in soil properties before they lead to more serious and visible forms of soil degradation. The methodological approach presented here constitutes one tool to incorporate local demands and perceptions of soil management constraints as an essential input to relevant research for development activities. The participatory process followed was effective in facilitating farmer consensus; for example, about which soil related constraints were most important and what potential soil management options could be used. Development of local capacities for consensus building constitute a critical step prior to collective action by farming communities resulting in the adoption of integrated soil fertility management strategies at the farm and landscape scale
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