Search results for "Primary"
showing 10 items of 2384 documents
Two-dimensional Banach spaces with polynomial numerical index zero
2009
We study two-dimensional Banach spaces with polynomial numerical indices equal to zero.
Vertical versus horizontal Sobolev spaces
2020
Let $\alpha \geq 0$, $1 < p < \infty$, and let $\mathbb{H}^{n}$ be the Heisenberg group. Folland in 1975 showed that if $f \colon \mathbb{H}^{n} \to \mathbb{R}$ is a function in the horizontal Sobolev space $S^{p}_{2\alpha}(\mathbb{H}^{n})$, then $\varphi f$ belongs to the Euclidean Sobolev space $S^{p}_{\alpha}(\mathbb{R}^{2n + 1})$ for any test function $\varphi$. In short, $S^{p}_{2\alpha}(\mathbb{H}^{n}) \subset S^{p}_{\alpha,\mathrm{loc}}(\mathbb{R}^{2n + 1})$. We show that the localisation can be omitted if one only cares for Sobolev regularity in the vertical direction: the horizontal Sobolev space $S_{2\alpha}^{p}(\mathbb{H}^{n})$ is continuously contained in the vertical Sobolev sp…
Reactions in the presence of irradiated semiconductors: Are they simply photocatalytic?
2018
A generally accepted classification distinguishes semiconductor photocatalysis in type A and type B. The first class comprehends reactions where the primary redox products (radical anions and cations) further evolve giving rise to the final reduced and oxidized species. Type B reactions occur when the primary redox products undergo intermolecular bond formation to addition products. Recently, some photocatalytic reactions have been reported wherein the photocatalytically produced compounds are not the final products. In fact, they react in the solution bulk or catalytically on the surface of the semiconductor with other species thus producing the target compounds. These reactions, hereby re…
Assessment of the Potential Evapotranspiration MODIS Product Using Ground Measurements in the Pampas
2018
Evapotranspiration is the hydrological variable of greatest relevance in the Argentina Pampas Region (APR). The estimation of potential evapotranspiration (PET) in this area becomes essential since primary productivity is directly linked to water availability. In order to evaluate the MOD16_A2 product of evapotranspiration (ET), a comparison with in situ measurements was conducted. We used ET data provided by the Oficina de Riesgo Agropecuario, corresponding to 24 stations placed in the region covering all seasons for the years 2012 to 2014. Results show an overestimation of 86% and 52% in Autumn-Winter and Spring-Summer, respectively. Mean Absolut Error (MAE) range between ±0.9 and ±2.1 mm…
Beyond APAR and NPQ: Factors Coupling and Decoupling SIF and GPP Across Scales
2021
The connection between solar-induced fluorescence (SIF) and vegetation gross primary productivity is being widely investigated across spatial, temporal, and biological scales, including: a) studies at the leaf [1], [2], plant canopy [2]–[4] or satellite pixel scale [5], [6], b) temporally with studies spanning from diurnal [7] to seasonal scales [1], [3], [5], and b) biologically with studies covering various plant functional types (PFTs), e.g., crops [4], [7], deciduous [8] or evergreen forests [1], [3], in response to different sources of stress.
Three X-ray Flares Near Primary Eclipse of the RS CVn Binary XY UMa
2016
We report on an archival X-ray observation of the eclipsing RS CVn binary XY UMa ($\rm P_{orb}\approx$ 0.48d). In two $\emph{Chandra}$ ACIS observations spanning 200 ks and almost five orbital periods, three flares occurred. We find no evidence for eclipses in the X-ray flux. The flares took place around times of primary eclipse, with one flare occurring shortly ($<0.125\rm P_{orb}$) after a primary eclipse, and the other two happening shortly ($<0.05\rm P_{orb}$) before a primary eclipse. Two flares occurred within roughly one orbital period ($\Delta \phi\approx1.024\rm P_{orb}$) of each other. We analyze the light curve and spectra of the system, and investigate coronal length scales both…
Linking photosynthesis and sun-induced fluorescence at sub-daily to seasonal scales
2018
Abstract Due to its close link to the photosynthetic process, sun-induced chlorophyll fluorescence (F) opens new possibilities to study dynamics of photosynthetic light reactions and to quantify CO2 assimilation rates. Although recent studies show that F is linearly related to gross primary production (GPP) on coarse spatial and temporal scales, it is argued that this relationship may be mainly driven by seasonal changes in absorbed photochemical active radiation (APAR) and less by the plant light use efficiency (LUE). In this work a high-resolution spectrometer was used to continuously measure red and far-red fluorescence and different reflectance indices within a sugar beet field during t…
Remote sensing of solar-induced chlorophyll fluorescence (SIF) in vegetation: 50 years of progress
2019
Remote sensing of solar-induced chlorophyll fluorescence (SIF) is a rapidly advancing front in terrestrial vegetation science, with emerging capability in space-based methodologies and diverse application prospects. Although remote sensing of SIF – especially from space – is seen as a contemporary new specialty for terrestrial plants, it is founded upon a multi-decadal history of research, applications, and sensor developments in active and passive sensing of chlorophyll fluorescence. Current technical capabilities allow SIF to be measured across a range of biological, spatial, and temporal scales. As an optical signal, SIF may be assessed remotely using high-resolution spectral sensors in …
Social Representations of Flooding of Future Teachers of Primary Education (Social Sciences): A Geographical Approach in the Spanish Mediterranean Re…
2020
The risk of flooding is the main natural hazard that affects the European Mediterranean region. This hazard has worsened in recent decades due to the occupation of flood areas and the effects of climate change. Therefore, understanding and gaining a more in-depth knowledge of social representations of flooding is important. In addition, interest in this subject is accentuated in the case of future teachers. This is because it is mandatory to teach this subject in Primary Education (Grades 1&ndash
2016
Gianluca Tramontana was supported by the GEOCARBON EU FP7 project (GA 283080). Dario Papale, Martin Jung and Markus Reichstein acknowledge funding from the EU FP7 project GEOCARBON (grant agreement no. 283080) and the EU H2020 BACI project (grant agreement no. 640176). Gustau Camps-Valls wants to acknowledge the support by an ERC Consolidator Grant with grant agreement 647423 (SEDAL). Kazuhito Ichii was supported by Environment Research and Technology Development Funds (2-1401) from the Ministry of the Environment of Japan and the JAXA Global Change Observation Mission (GCOM) project (no. 115). Christopher R. Schwalm was supported by National Aeronautics and Space Administration (NASA) gran…