190 research outputs found
Materials property prediction using symmetry-labeled graphs as atomic-position independent descriptors
Computational materials screening studies require fast calculation of the
properties of thousands of materials. The calculations are often performed with
Density Functional Theory (DFT), but the necessary computer time sets
limitations for the investigated material space. Therefore, the development of
machine learning models for prediction of DFT calculated properties are
currently of interest. A particular challenge for \emph{new} materials is that
the atomic positions are generally not known. We present a machine learning
model for the prediction of DFT-calculated formation energies based on Voronoi
quotient graphs and local symmetry classification without the need for detailed
information about atomic positions. The model is implemented as a message
passing neural network and tested on the Open Quantum Materials Database (OQMD)
and the Materials Project database. The test mean absolute error is 20 meV on
the OQMD database and 40 meV on Materials Project Database. The possibilities
for prediction in a realistic computational screening setting is investigated
on a dataset of 5976 ABSe selenides with very limited overlap with the OQMD
training set. Pretraining on OQMD and subsequent training on 100 selenides
result in a mean absolute error below 0.1 eV for the formation energy of the
selenides.Comment: 14 pages including references and 13 figure
Linear basal cell carcinoma of the lower eyelid: Reconstruction with a musculocutaneous transposition flap
Linear basal cell carcinoma (LBCC) is a rare
morphologic variant of basal cell carcinoma. It is
defined as a basal cell carcinoma that grows
following a linear pattern, with a longitudinal
diameter longer that its width. This entity was first
reported by Lewis in 1985,1 and since then
approximately 50 new cases have been described.
LBCC characteristically spreads following relaxed
skin tension lines, and the most frequent site is the
lower eyelid. Currently, some controversy exists
regarding the most appropriate surgical approach
and reconstructive technique for LBCC. For this
reason, we present 2 cases recently managed in
our center
Random-walk simulation of cell migration and proliferation
Cell migration and proliferation has been modelled in several works of the literature as a process similar to diffusion. However, diffusion models to simulate the proliferation and migration of cells tend to create a homogeneous distribution in the cell density, but this result is not real. Diffusion is not the mechanism of cell dispersal: cells disperse by crawling or proliferation, or are transported in a moving fluid. The use of stochastic models or other (cellular automata, models particles, etc...) can modify this limitation. Therefore, this paper presents a stochastic model (random-walk) to simulate the proliferation and migration of cells. Both processes are considered as completely stochastic as discrete. The model developed aims to predict the behavior of in vitro cell cultures performed with adult muscle satellite cells. Non homogeneous distribution of cells has been observed inside the culture well. Using previous stochastic model we have been able to predict the non homogeneous cell distribution and accurate quantitative results have been computed. In a future, the model will allow us to incorporate other aspects such as cell differentiation, incorporate several cell populations simultaneously, etc
Sierpi\'{n}ski curve Julia sets for quadratic rational maps
We investigate under which dynamical conditions the Julia set of a quadratic
rational map is a Sierpi\'{n}ski curveComment: 19 pages, 10 Figures, Substancial modification of previous version,
Accepted for publication in Ann. Acad. Sci. Fenn. Mat
Capture zones of the family of functions lambda z^m exp(z)
We consider the family of entire transcendental maps given by where m>=2. All functions have a
superattracting fixed point at z=0, and a critical point at z=-m. In the
dynamical plane we study the topology of the basin of attraction of z=0. In the
parameter plane we focus on the capture behaviour, i.e., \lambda values such
that the critical point belongs to the basin of attraction of z=0. In
particular, we find a capture zone for which this basin has a unique connected
component, whose boundary is then non-locally connected. However, there are
parameter values for which the boundary of the immediate basin of z=0 is a
quasicircle.Comment: 25 pages, 14 figures. Accepted for publication in the International
Journal of bifurcation and Chao
Workflow reuse in practice: a study of neuroimaging pipeline users
Workflow reuse is a major benefit of workflow systems and shared workflow repositories, but there are barely any studies that quantify the degree of reuse of workflows or the practical barriers that may stand in the way of successful reuse. In our own work, we hypothesize that defining workflow fragments improves reuse, since end-to-end workflows may be very specific and only partially reusable by others. This paper reports on a study of the current use of workflows and workflow fragments in labs that use the LONI Pipeline, a popular workflow system used mainly for neuroimaging research that enables users to define and reuse workflow fragments. We present an overview of the benefits of workflows and workflow fragments reported by users in informal discussions. We also report on a survey of researchers in a lab that has the LONI Pipeline installed, asking them about their experiences with reuse of workflow fragments and the actual benefits they perceive. This leads to quantifiable indicators of the reuse of workflows and workflow fragments in practice. Finally, we discuss barriers to further adoption of workflow fragments and workflow reuse that motivate further work
SensoGraph: Using proximity graphs for sensory analysis
Sensory evaluation of foods is as important as chemical, physical or microbiological examinations, being specially relevant in food industries. Classical methods can be long and costly, making them less suitable for certain industries like the wine industry. Some alternatives have arisen recently, including Napping®, where the tasters represent the sensory distances between products by positioning them on a tablecloth; the more similar they perceive the products, the closer they position them on the tablecloth. This method uses multiple factor analysis (MFA) to process the data collected. The present paper introduces the software SensoGraph, which makes use of proximity graphs to analyze those data. The application is described and experimental results are presented in order to compare the performances of SensoGraph and Napping®, using eight wines from the Toro region and two groups of twelve tasters with different expertise.Ministerio de Ciencia e InnovaciónEuropean Science FoundationJunta de Castilla y Leó
PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data
The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches
PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data
The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches
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