Search results for "Light"
showing 10 items of 3575 documents
Combined dynamics of the 500–600 nm leaf absorption and chlorophyll fluorescence changes in vivo: Evidence for the multifunctional energy quenching r…
2021
Carotenoids (Cars) regulate the energy flow towards the reaction centres in a versatile way whereby the switch between energy harvesting and dissipation is strongly modulated by the operation of the xanthophyll cycles. However, the cascade of molecular mechanisms during the change from light harvesting to energy dissipation remains spectrally poorly understood. By characterizing the in vivo absorbance changes (Delta A) of leaves from four species in the 500-600 nm range through a Gaussian decomposition, while measuring passively simultaneous Chla fluorescence (F) changes, we present a direct observation of the quick antenna adjustments during a 3-min dark-to-high-light induction. Underlying…
Instrumentation for time-of-flight elastic recoil detection analysis
2016
Time-of-flight elastic recoil detection is an ion beam based method to analyze the elemental composition of thin film samples at different depths. In order to improve the mass resolution and to enable kinematic correction a position sensitive gas ionization chamber energy detector was constructed. This detector along with pre-existing timing detectors were connected to a modern fully digitizing data acquisition setup. This thesis describes the design of these instruments, including all aspects from the mechanical design of the gas ionization detector to the algorithm and software development of the digitizing acquisition setup. The performance of the system has been studied with measurements …
Asylum Migration, Borders, and Terrorism in a Structural Gravity Model
2021
This article has benefited from very helpful comments from two anonymous reviewers and the Academic Editor Inmaculada Martinez. The authors would like to acknowledge the financial support from Junta de Andalucia (SEJ 413), from Generalitat Valenciana (GV Prometeo 2018/102 and GV/2020/012), the Spanish Ministry of Science, Innovation and Universities (RTI2018-100899-B-I00, co-financed with FEDER), and the Kellogg Institute for International Studies (University of Notre Dame).
Is there light after depth? Distribution of periphyton chlorophyll and productivity in lake littoral zones
2014
Periphyton and phytoplankton contribute to the base of lake food webs, and both groups of microalgae are influenced by resources and physical forcing. Spatial variation in light availability interacts with the physical dynamics of the water column to create predictable depth gradients in resources and disturbance that may differentially affect periphyton vs phytoplankton. We characterized the depth distribution of chlorophyll and productivity of periphyton on sediments (epipelon) and phytoplankton in the euphotic zones of 13 oligomesotrophic lakes that span a large size gradient (0.017–32,600 km2 ). Epipelic chlorophyll usually increased with depth in the epilimnion. Light was the primary d…
GÉOCARREFOUR KEY WORDS Local level development planning, night-time, light pollution, branding, energy transition
2015
La pollution lumineuse est progressivement devenue un enjeu environnemental. Elle produit ainsi de nouveaux périmètres pour l’action publique, dans un contexte de transition énergétique incitant à modifier les pratiques d’éclairage public pour protéger la « nuit noire ». Pour les territoires de faible densité, cette vision renouvelée de la nuit constitue une « aubaine » en termes de développement territorial. Des processus différenciés de protection, de labellisation et de mise en tourisme des « ressources environnementales nocturnes » émergent, devenant ainsi un levier de la transition énergétique. For several decades, the negative impacts of artificial light on environmental mechanisms ha…
Un palimpsesto pedagógico. La educación de las mujeres en los Dísticos de Catón de León de Arroyal (1797)
2021
Este trabajo analiza el papel central que el género desempeñó en los imaginarios ilustrados y liberales y los modos en que éstos reinterpretaron el pasado, a partir de un estudio de caso: el de León Arroyal, liberal español, y su traducción (más bien, reescritura) de una obra pedagógica del humanista del siglo XVI Erasmo de Rotterdam. Revisar la propuesta de Arroyal para la formación de las mujeres en relación con el resto de su obra educativa y política, su experiencia vital, las tradiciones intelectuales de las que se nutre y otras propuestas contemporáneas españolas y europeas revela el peso del humanismo cristiano en su versión más restrictiva y severa, en contraste con un modelo de edu…
Calculate Pulse from Touch Error Free PPG Signal with 2ndOrder Butterworth Filter
2021
With the ongoing heart problems of the population worldwide, the medical requirements of the people are expected to increase. Electrocardiogram (ECG) is one of the proven to capture the heart response signal to assess the electrical and muscular functions of the heart. The ECG setup is expensive and needs proper training, and of course, it is not instant. For fast, accurate heart parameter monitoring, scientists pay attention to the photoplethysmogram signal (PPG), based on the light intensity of a particular wavelength. Android smartphone with a good quality camera has come to ordinary people's reach and has become one of the most necessary and rugged devices for today and future generatio…
Origin of the large spectral shift in electroluminescence in a blue light emitting cationic iridium(III) complex
2007
A new, but archetypal compound [ Ir( ppy- F-2) (2)Me(4)phen] PF6, where ppy- F2 is 2-(2',4'- fluorophenyl) pyridine and Me(4)phen is 3,4,7,8- tetramethyl- 1,10- phenanthroline, was synthesized and used to prepare a solid-state light-emitting electrochemical cell (LEEC). This complex emits blue light with a maximum at 476 nm when photoexcited in a thin film, with a photoluminescence quantum yield of 52%. It yields an efficient single-component solid-state electroluminescence device with a current efficiency reaching 5.5 cd A(-1) and a maximum power efficiency of 5.8 Lm Watt(-1). However, the electroluminescence spectrum is shifted with respect to the photoluminescence spectrum by 80 nm resul…
<title>Refractive properties of separate erythrocytes of Chernobyl clean-up workers at different pH</title>
2000
This study is focused on the modifications in erythrocytes of Chernobyl nuclear power plant accident clean-up workers as a late health effect of short-term impact of high level radioactive contamination. As a result, a new method based on erythrocyte (RBC) refractive index properties at different pH has been elaborated. According to the light dispersion theory for fluids refractive index is associated with molecules mass m. This feature is widely used for estimation of cell dry mass. But there is another refractive index dependency from molecules charge q regardless of its sing. This feature is not being used for cell quantitative and qualitative characterization. In this study, RBC were in…
Active photonic crystals based on surface acoustic waves
2003
An active photonic crystal (PC) based on the modulation of a one-dimensional cavity resonator by electrically-generated surface acoustic waves is described. The high nonthermal population of surface modes combined with the enhanced Brillouin scattering in the cavity increases the intensity of the scattered light to values comparable to the excitation intensity. This process is employed to switch and modulate light beams in PCs.