Search results for "Variation"
showing 10 items of 2124 documents
Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest
2012
Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …
Genetic and Epigenetic Factors of Takotsubo Syndrome: A Systematic Review
2021
Takotsubo syndrome (TTS), recognized as stress’s cardiomyopathy, or as left ventricular apical balloon syndrome in recent years, is a rare pathology, described for the first time by Japanese researchers in 1990. TTS is characterized by an interindividual heterogeneity in onset and progression, and by strong predominance in postmenopausal women. The clear causes of these TTS features are uncertain, given the limited understanding of this intriguing syndrome until now. However, the increasing frequency of TTS cases in recent years, and particularly correlated to the SARS-CoV-2 pandemic, leads us to the imperative necessity both of a complete knowledge of TTS pathophysiology for identifying bi…
Sharp capacity estimates for annuli in weighted R^n and in metric spaces
2017
We obtain estimates for the nonlinear variational capacity of annuli in weighted R^n and in metric spaces. We introduce four different (pointwise) exponent sets, show that they all play fundamental roles for capacity estimates, and also demonstrate that whether an end point of an exponent set is attained or not is important. As a consequence of our estimates we obtain, for instance, criteria for points to have zero (resp. positive) capacity. Our discussion holds in rather general metric spaces, including Carnot groups and many manifolds, but it is just as relevant on weighted R^n. Indeed, to illustrate the sharpness of our estimates, we give several examples of radially weighted R^n, which …
Minimality via second variation for microphase separation of diblock copolymer melts
2017
Abstract We consider a non-local isoperimetric problem arising as the sharp interface limit of the Ohta–Kawasaki free energy introduced to model microphase separation of diblock copolymers. We perform a second order variational analysis that allows us to provide a quantitative second order minimality condition. We show that critical configurations with positive second variation are indeed strict local minimizers of the problem. Moreover, we provide, via a suitable quantitative inequality of isoperimetric type, an estimate of the deviation from minimality for configurations close to the minimum in the L 1 {L^{1}} -topology.
Improved SiRNA Loading of Cationic Nanohydrogel Particles by Variation of Crosslinking Density
2019
Coarticulació i harmonia vocàlica en valencià septentrional
2011
L’harmonia vocàlica del valencià és un fenomen pel qual la vocal àtona final a s’assimila a les vocals mitjanes tòniques [ɛ] i [ɔ] precedents (cf. terra [ˈtɛrɛ], cosa [ˈkɔzɔ]). Una de les assumpcions de la bibliografia és que aquesta assimilació s’associa amb l’especial obertura de les vocals mitjanes obertes en valencià. En aquest treball estudiarem dos parlars pertanyents al valencià septentrional —el de Nules, que no presenta harmonia, i el de Borriana, que presenta harmonia únicament en la sèrie velar— per comprovar si, efectivament, l’harmonia implica una major obertura de la vocal [ɔ] en el parlar de Borriana. Amb aquest objectiu analitzarem i compararem els valors dels formants de le…
A new approach to register variation : the missing link
2006
El objetivo del presente artículo es dirigir la atención de los especialistas hacia la noción de registro lingüístico con el fin de promover nuevos métodos de analizar los registros actuales. A pesar de la falta de claridad en su definición y la frecuente confusión con otros tipos de variación lingüística, el movimiento a través de toda la gama de registros es uno de los instrumentos comunicativos más efectivos y de uso más frecuente que posee una lengua para adaptarse a los diversos entornos privados, sociales y profesionales. Sin embargo, este movimiento es uno de los mecanismos más difíciles de percibir, aprender y utilizar correctamente, sobre todo en el caso de hablantes extranjeros y …
Gradient flows in random walk spaces
2021
El món digital ha comportat l'aparició de molts tipus de dades, de mida i complexitat creixents. De fet, els dispositius moderns ens permeten obtenir fàcilment imatges de major resolució, així com recopilar dades sobre cerques a la xarxa, anàlisis sanitàries, xarxes socials, sistemes d'informació geogràfica, etc. En conseqüència, l'estudi i el tractament d'aquests grans conjunts de dades té un gran interès i valor. En aquest sentit, els grafs ponderats proporcionen un espai de treball natural i flexible on representar les dades. En aquest context, un vèrtex representa una dada concreta i a cada aresta se li assigna un pes segons alguna mesura de semblança adequadament triada entre els vèrte…
Global diversity in the TAS2R38 bitter taste receptor: revisiting a classic evolutionary PROPosal
2016
AbstractThe ability to taste phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) is a polymorphic trait mediated by the TAS2R38 bitter taste receptor gene. It has long been hypothesized that global genetic diversity at this locus evolved under pervasive pressures from balancing natural selection. However, recent high-resolution population genetic studies of TAS2Rs suggest that demographic events have played a critical role in the evolution of these genes. We here utilized the largest TAS2R38 database yet analyzed, consisting of 5,589 individuals from 105 populations, to examine natural selection, haplotype frequencies and linkage disequilibrium to estimate the effects of both selectio…
Is mental health literacy for depression associated with the intention toward preventive actions? A cross-sectional study among university students
2021
Objective Mental Health Literacy (MHL) might play an important role in preventing depression. This study assessed the MHL level for depression of university students and its association with intentions toward preventive actions against depression. Participants: University students (n = 315) were surveyed online. Methods: MHL level and group differences were analyzed using t-tests and one-way ANOVA. To investigate the relation between MHL and the intention for preventive actions against depression, correlation and regression analyses were performed. Results: The mean MHL level of the participants was reasonably high (42.65 of 75 points). MHL levels differed significantly between different gr…