Search results for "Ocean"
showing 10 items of 2919 documents
La memòria oceànica del clima: El sistema circulatori d'un planeta viu
2013
A principis del segle XVI Leonardo da Vinci comparava els corrents oceànics amb el fl ux de sang d’un cos humà. Actualment disposem d’informació sufi cient per a explorar la idea que la Terra té un sistema circulatori responsable de capturar, transformar i distribuir l’energia solar. El paper dels oceans com a reguladors del clima és extraordinari, realment condicionen el present i el futur del planeta.
Technology-enhanced or Technology-exhausted Learning in Adult Migrant Literacy Education in Finland : Exploring Teachers’ Experiences and Views in Pr…
2023
This exploratory mixed data study investigated the role of technology in adult migrant language and late literacy education in Finland. In addition to an online pre-pandemic survey targeted at Finnish language and literacy teachers, four in-service teachers were interviewed during the COVID-19 pandemic in late 2020. With means of qualitative content analysis an account of teachers’ individual experiences and views of technology-equipped language and literacy learning was generated. Problematic issues were the use of devices for educational purposes, lacking user experience, inadequate provision of suitable devices, IT courses, and insufficient support for learners and teachers, causing ineq…
Measurement of nonlinear and chromatic dispersion parameters of optical fibers using modulation instability
2006
International audience; We present a simple method for the measurement of Kerr, second- and third-order dispersion coefficients in optical fibers using power and dispersion dependences of modulation instability near the zero-dispersion wavelength. We also complete the analysis by the accurate determination of the zero-dispersion wavelength of the fiber using the phase-matched four wave mixing process which occurs near this specific wavelength.
Signal processing in photonic crystals and nanostructures
2006
International audience; Optical devices employing photonic crystals and novel nanostructure materials may exhibit useful properties for applications to all-optical signal processing. In this work we analyze as a first example four-wave mixing of polarized beams in photonic crystal fibers. We show that by properly tuning the pump wavelength and the linear dispersion properties of the fiber one may obtain broadband parametric amplification and frequency conversion. Next we consider the in-line periodic amplification of short optical pulses by means of quantum-dot semiconductor optical amplifiers. We show by numerical simulations that pattern-free amplification of a 40 Gbit/s soliton signal at…
Natural Halogen Emissions to the Atmosphere: Sources, Flux, and Environmental Impact
2022
Understanding the atmospheric geochemical cycle of both natural and anthropogenic halogens is important because of the detrimental effect halogens have on the environment, notably on tropospheric and stratospheric ozone. Oceans are the primary natural source for atmospheric Cl, F, Br, and I, but anthropogenic emissions are still important, especially for Cl. While emissions of human-made halocarbons (e.g., chlorofluorocarbons or CFCs) are expected to continue to decrease allowing progressive stratospheric ozone recovery, volcanic activity (e.g., clusters of mid-scale explosive eruptions or large-scale explosive eruptions) might disturb this recovery over the next decades. This review provid…
A conceptual analysis of the oceanic feeling : with a special note on painterly aesthetics
2015
INFLUENZA DELLA DENSITÀ DI UN PRATO DI POSIDONIA OCEANICA SULLA RESISTENZA AL MOTO IN ACQUE BASSE
2008
L’impiego di modelli di circolazione per la gestione di acque costiere, quali lagune, paludi, ecc., richiede la valutazione degli effetti della vegetazione acquatica, i quali crescono al diminuire della profondità idrica. Una pianta tipica dei fondi sabbiosi sotto costa del Mar Mediterraneo è la Posidonia oceanica, la quale per le sue caratteristiche (ciuffi di foglie nastriformi molto flessibili e lunghe fino a 1,5 m) costituisce una particolare scabrezza, poiché al crescere della velocità della corrente le foglie si incurvano sempre più fino ad adagiarsi sul fondo. Nella presente memoria si rielaborano tutti insieme i dati sperimentali di due precedenti indagini degli scriventi, riguardan…
Surcotes, tempêtes et risque d’inondation le long du littoral belge : variabilité contemporaine et future (1950-2100)
2010
6 pages; International audience; A l’échelle quotidienne, la hauteur des surcotes à Ostende est quasi-linéairement corrélée à la pressionatmosphérique de surface (PSM) sur la Mer Baltique. Les plus fortes surcotes s’y produisent quand une dépression restestationnaire plusieurs jours sur la Scandinavie synchrone à un renforcement de l’anticyclone des Açores. Cette géographiebarométrique favorise la genèse des forts vents d’afflux de nord-ouest dans la partie sud de la Mer du Nord. Un modèle derégression linéaire permet de simuler de façon robuste la variabilité interannuelle des fortes surcotes à Ostende de 1950 à2000 avec (i) la PSM autour de la Mer Baltique et (ii) le gradient barométrique…
KOSMOS 2017 Peru Side Experiment: nutrients, phytoplankton abundances, enzyme rates, photophysiology
2022
This data was collected during an short-term incubation experiment in March 2017 that investigated the response of a surface plankton community to upwelling. This experiment was carried in the framework of the SFB754-funded KOSMOS mesocosm study that took place in La Punta, Callao, Peru between February-April 2017. A total of six different treatments were used to disentangle chemical and biological characteristics of deep water that influence surface plankton blooms: 2 different deep water sources with different nutrient concentrations; 3 treatments to distinguish the effects of inorganic nutrients, organic nutrients and deep water microbial populations. Measured variables include inorganic…
Biological and Proteomic Characterization of the Anti-Cancer Potency of Aqueous Extracts from Cell-Free Coelomic Fluid of Arbacia lixula Sea Urchin i…
2022
Echinoderms are an acknowledged source of bioactive compounds exerting various beneficial effects on human health. Here, we examined the potential in vitro anti-hepatocarcinoma effects of aqueous extracts of the cell-free coelomic fluid obtained from the sea urchin Arbacia lixula using the HepG2 cell line as a model system. This was accomplished by employing a combination of colorimetric, microscopic and flow cytometric assays to determine cell viability, cell cycle distribution, the possible onset of apoptosis, the accumulation rate of acidic vesicular organelles, mitochondrial polarization, cell redox state and cell locomotory ability. The obtained data show that exposed HepG2 cells under…