977 research outputs found
Plants and sodium ions: keeping company with the enemy
Plants face a dilemma about sodium metabolism. Uptake of ubiquitous sodium ions is desirable as a way to build osmotic potential, absorb water and sustain turgor, but excess sodium ions may be toxic. Information from a number of plant species about the proteins involved in sodium-ion uptake helps to explain how plants manage to take in just the right amount
Quiz Games as a model for Information Hiding
We present a general computation model inspired in the notion of information
hiding in software engineering. This model has the form of a game which we call
quiz game. It allows in a uniform way to prove exponential lower bounds for
several complexity problems of elimination theory.Comment: 46 pages, to appear in Journal of Complexit
The Space Interferometry Mission Astrometric Grid Giant-Star Survey. I. Stellar Parameters and Radial Velocity Variability
We present results from a campaign of multiple epoch echelle spectroscopy of
relatively faint (V = 9.5-13.5 mag) red giants observed as potential
astrometric grid stars for the Space Interferometry Mission (SIM PlanetQuest).
Data are analyzed for 775 stars selected from the Grid Giant Star Survey
spanning a wide range of effective temperatures (Teff), gravities and
metallicities. The spectra are used to determine these stellar parameters and
to monitor radial velocity (RV) variability at the 100 m/s level. The degree of
RV variation measured for 489 stars observed two or more times is explored as a
function of the inferred stellar parameters. The percentage of radial velocity
unstable stars is found to be very high -- about 2/3 of our sample. It is found
that the fraction of RV-stable red giants (at the 100 m/s level) is higher
among stars with Teff \sim 4500 K, corresponding to the calibration-independent
range of infrared colors 0.59 < (J-K_s)_0 < 0.73. A higher percentage of
RV-stable stars is found if the additional constraints of surface gravity and
metallicity ranges 2.3< log g < 3.2 and -0.5 < [Fe/H] < -0.1, respectively, are
applied. Selection of stars based on only photometric values of effective
temperature (4300 K < Teff < 4700 K) is a simple and effective way to increase
the fraction of RV-stable stars. The optimal selection of RV-stable stars,
especially in the case when the Washington photometry is unavailable, can rely
effectively on 2MASS colors constraint 0.59 < (J-K_s)_0 < 0.73. These results
have important ramifications for the use of giant stars as astrometric
references for the SIM PlanetQuest.Comment: Astronomical Journal, in press, 22 pages, 11 Postscript figures, uses
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Predicting morbidity by local similarities in multi-scale patient trajectories
[EN] Patient Trajectories (PTs) are a method of representing the temporal evolution of patients. They can include information from different sources and be used in socio-medical or clinical domains. PTs have generally been used to generate and study the most common trajectories in, for instance, the development of a disease. On the other hand, healthcare predictive models generally rely on static snapshots of patient information. Only a few works about prediction in healthcare have been found that use PTs, and therefore benefit from their temporal dimension. All of them, however, have used PTs created from single-source information. Therefore, the use of longitudinal multi-scale data to build PTs and use them to obtain predictions about health conditions is yet to be explored. Our hypothesis is that local similarities on small chunks of PTs can identify similar patients concerning their future morbidities. The objectives of this work are (1) to develop a methodology to identify local similarities between PTs before the occurrence of morbidities to predict these on new query individuals; and (2) to validate this methodology on risk prediction of cardiovascular diseases (CVD) occurrence in patients with diabetes. We have proposed a novel formal definition of PTs based on sequences of longitudinal multi-scale data. Moreover, a dynamic programming methodology to identify local alignments on PTs for predicting future morbidities is proposed. Both the proposed methodology for PT definition and the alignment algorithm are generic to be applied on any clinical domain. We validated this solution for predicting CVD in patients with diabetes and we achieved a precision of 0.33, a recall of 0.72 and a specificity of 0.38. Therefore, the proposed solution in the diabetes use case can result of utmost utility to secondary screening.This work was supported by the CrowdHealth project (COLLECTIVE WISDOM DRIVING PUBLIC HEALTH POLICIES (727560)) and the MTS4up project (DPI2016-80054-R).Carrasco-Ribelles, LA.; Pardo-Más, JR.; Tortajada, S.; Sáez Silvestre, C.; Valdivieso, B.; Garcia-Gomez, JM. (2021). Predicting morbidity by local similarities in multi-scale patient trajectories. Journal of Biomedical Informatics. 120:1-9. https://doi.org/10.1016/j.jbi.2021.103837S1912
Development of Active Barrier Multilayer Films Based on Electrospun Antimicrobial Hot-Tack Food Waste Derived Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Cellulose Nanocrystal Interlayers
[EN] Active multilayer films based on polyhydroxyalkanoates (PHAs) with and without high barrier coatings of cellulose nanocrystals (CNCs) were herein successfully developed. To this end, an electrospun antimicrobial hot-tack layer made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) derived from cheese whey, a by-product from the dairy industry, was deposited on a previously manufactured blown film of commercial food contact PHA-based resin. A hybrid combination of oregano essential oil (OEO) and zinc oxide nanoparticles (ZnONPs) were incorporated during the electrospinning process into the PHBV nanofibers at 2.5 and 2.25 wt%, respectively, in order to provide antimicrobial properties. A barrier CNC coating was also applied by casting from an aqueous solution of nanocellulose at 2 wt% using a rod at 1m/min. The whole multilayer structure was thereafter assembled in a pilot roll-to-roll laminating system, where the blown PHA-based film was located as the outer layers while the electrospun antimicrobial hot-tack PHBV layer and the barrier CNC coating were placed as interlayers. The resultant multilayer films, having a final thickness in the 130-150 mu m range, were characterized to ascertain their potential in biodegradable food packaging. The multilayers showed contact transparency, interlayer adhesion, improved barrier to water and limonene vapors, and intermediate mechanical performance. Moreover, the films presented high antimicrobial and antioxidant activities in both open and closed systems for up to 15 days. Finally, the food safety of the multilayers was assessed by migration and cytotoxicity tests, demonstrating that the films are safe to use in both alcoholic and acid food simulants and they are also not cytotoxic for Caco-2 cells.The Spanish Ministry of Science and Innovation (MICI) through the RTI2018-097249-B-C21 program number and the EU H2020 YPACK (reference number 773872) projects funded this research.Figueroa-Lopez, KJ.; Torres-Giner, S.; Angulo, I.; Pardo-Figuerez, M.; Escuin, JM.; Bourbon, AI.; Cabedo, L.... (2020). Development of Active Barrier Multilayer Films Based on Electrospun Antimicrobial Hot-Tack Food Waste Derived Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Cellulose Nanocrystal Interlayers. Nanomaterials. 10(12):1-24. https://doi.org/10.3390/nano10122356S124101
PS/PMMA-CdSe/ZnS Quantum Dots Hybrid Nanofibers for VOCs Sensors
Hybrid nanofibers containing CdSe/ZnS quantum dots have been produced by electrospinning of hybrid latexes to characterize the electro‐optical behavior of this novel luminescent sensing material. The latexes are synthesized by seeded semi‐batch emulsion polymerization yielding cross‐linked core‐shell PS/QDs/PMMA particles with efficiently encapsulated quantum dots guaranteeing a good optical stability. Addition of polyvinyl alcohol (PVA) or polyethylene oxide (PEO) to the latexes is necessary to produce polymeric dispersions suitable for electrospinning manufacture of the nanometric fibers. The optimized polymeric dispersions are successfully electrospun obtaining fluorescent nanofibers in both cases. The hybrid nanofibers are sensitive to selected solvents (acetone, methanol and THF) and present positive response making them good candidates for the production of VOC sensors.Basque Government IT999-16 and ELKARTEK KK-2016/00030 and KK-2017/00089 and the Spanish Government (Ministerio de Economía y competitividad Project CTQ2014-59016-P and TEC2015-63838-C3-3-R. Alicia de San Luis acknowledges de Spanish Government for the scholarliship (FPI-MICINN 2012). The sGIKER UPV/EHU is also aknowledged for the elctron microscopy facilities of the Gipuzkoa unit
Molecular survey of CRL618
We present the complete data set, model and line identification of a survey
of the emission from the C-rich protoplanetary nebula CRL 618 performed with
the IRAM-30m telescope in the following frequency ranges: 80.25-115.75 GHz,
131.25-179.25 GHz, and 204.25-275.250 GHz. A selection of lines from different
species has been used in previous works to derive the structure of the source,
its physical conditions and the chemical abundances in the different gas
regions. In this work, we have used this information to run a global simulation
of the spectrum in order to check the consistency of the model and to ease the
task of line identification. The total number of lines that have a
correspondence in both data and model is ~3100, although quite often in this
object many lines blend into complex features so that the model, that takes
into account line blending, is a key tool at this stage of the analysis. Of all
the lines that we have been able to label, ~55% of them belong to the different
forms of HC3N, and ~18% to those of HC5N. The density of remaining unidentified
features above the 3sigma limit is only one per ~2.1 GHz (74 features), which
is unprecedented in the analysis of this type of large millimeter-wave line
surveys.Comment: Accepted in ApJ (November 2006). Figures bitmapped to lower
resolution. The complete set of tables and figures will be published only
electronically (ApJ online
Solución Semi-analítica 1D para Funciones Uniparamétricas de Realce.
El proceso de realce resulta crucial en el análisis de imágenes. En esta contribución estudiamos el comportamiento numérico de filtros de difusión uniparamétricos que automaticen el estudio de estas imágenes. Para ello se propone la técnica de los tres píxeles que da lugar a una solución semianalítica del proceso de difusión no lineal con una función de difusión uniparamétric
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