Search results for " PUM"
showing 10 items of 412 documents
Effect of nanostructure layout on spin pumping phenomena in antiferromagnet/nonmagnetic metal/ferromagnet multilayered stacks
2017
In this work we focus on magnetic relaxation in Mn80Ir20(12 nm)/Cu(6 nm)/Py(dF) antiferromagnet/Cu/ferromagnet (AFM/Cu/FM) multilayers with different thickness of the ferromagnetic permalloy layer. An effective FM-AFM interaction mediated via the conduction electrons in the nonmagnetic Cu spacer – the spin-pumping effect – is detected as an increase in the linewidth of the ferromagnetic resonance (FMR) spectra and a shift of the resonant magnetic field. We further find experimentally that the spin-pumping-induced contribution to the linewidth is inversely proportional to the thickness of the Py layer. We show that this thickness dependence likely originates from the dissipative dynamics of …
Single crystal-like thin films of blue bronze
2021
Abstract Pulsed laser deposition technique was employed to grow thin films of K 0.3 M o O 3 on A l 2 O 3 (1-102) and S r T i O 3 (510) substrates. Structural and imaging characterization revealed good quality films with well oriented grains of few microns in length. Both non-selective (transport) and order-selective (femtosecond pump-probe spectroscopy) probes revealed charge density wave properties that are very close to those of the single crystals. The films exhibit metal-semiconductor phase transition in resistivity, pump-probe data show phase transition at the same temperature as the single crystal and the threshold for the photo-induced phase transition is approximately the same as in…
Enhancement of the Spin Pumping Effect by Magnon Confluence Process in YIG/Pt Bilayers
2019
The experimental investigation of the spin pumping process by dipolar‐exchange magnons parametrically excited in in‐plane magnetized yttrium iron garnet/platinum bilayers is presented. The electric voltage generated in the platinum layer via the inverse spin Hall effect (ISHE) results from contributions of two opposite spin currents formed by the longitudinal spin Seebeck effect and by the spin pumping from parametric magnons. In the field‐dependent measurements of the spin pumping‐induced component of the ISHE‐voltage, a clearly visible sharp peak is detected at high pumping powers. It is found that the peak position is determined by the process of confluence of two parametrically excited …
Shallow vent architecture during hybrid explosive-effusive activity at Cordón Caulle (Chile, 2011-12): Evidence from direct observations and pyroclas…
2013
International audience; In June 2011, an eruption of rhyolite magma began at the Puyehue-Cordón Caulle volcanic complex, southern Chile. By January 2012, explosive activity had declined from sustained pyroclastic (Plinian to sub-Plinian) fountaining to mixed gas and ash jetting punctuated by Vulcanian blasts. This explosive activity was accompanied by synchronous effusion of obsidian lava in a hybrid explosive-effusive eruption. Fortuitous climatic conditions permitted ground-based observation and video recording of transient vent dynamics as well as real-time collection of proximal juvenile ash as it sedimented from the active plume. The main eruptive vent complex and site of lava effusion…
Immunological detection of tonoplast polypeptides in the plasma membrane of pea cotyledons
1996
The tonoplast is usually characterized by the presence of two electrogenic proton pumps: a vacuolartype H+-ATPase and a pyrophosphatase, as well as a putative water-channel-forming protein (γ-TIP). Using a post-embedding immunogold labelling technique, we have detected the presence of these transport-protein complexes not only in the tonoplast, but also in the plasma membrane and trans Golgi elements of maturing pea (Pisum sativum L.) cotyledons. These ultrastructural observations are supported by Western blotting with highly purified plasma-membrane fractions. In contrast to the vacuolar-type H+-ATPase, whose activity was not measurable, considerable pyrophosphatase activity was detected i…
Factors controlling plankton community production, export flux, and particulate matter stoichiometry in the coastal upwelling system off Peru
2020
Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can modify surface production and related biogeochemical processes. Determining these factors is important because EBUS are considered hotspots of climate change, and reliable predictions of their future functioning requires understanding of the mechanisms driving the biogeochemical cycles therein. In this field experiment, we used in situ mesocosms as tools to improve our mechanistic understanding of processes controlling organ…
Different bacteria can enhance the micropropagation response of Cotoneaster lacteus (Rosaceae)
1998
C. MONIER, E. BOSSIS, C. CHABANET AND R. SAMSON. 1998. Cotoneaster species are widely used ornamental shrubs, and research is under way to select genotypes which are more resistant to fire blight by somaclonal variation. During the establishment of micropropagation, one genotype, Cotoneaster lacteus, showed the development of endogenous bacterial contaminants. Two strains were isolated from in vitro explants: Bacillus pumilus and Alcaligenes faecalis. These two strains, and some Pseudomonas fluorescens and Ps. putida, promoted in vitro multiplication and rooting of explants. In Pseudomonas strains, rooting enhancing capacity appeared to be related to indole-3-acetic acid (IAA) production, a…
Toward a better understanding of fish‐based contribution to ocean carbon flux
2021
Fishes are the dominant vertebrates in the ocean, yet we know little of their contribution to carbon export flux at regional to global scales. We synthesize the existing information on fish-based carbon flux in coastal and pelagic waters, identify gaps and challenges in measuring this flux and approaches to address them, and recommend research priorities. Based on our synthesis of passive (fecal pellet sinking) and active (migratory) flux of fishes, we estimated that fishes contribute an average (± standard deviation) of about 16.1% (± 13%) to total carbon flux out of the euphotic zone. Using the mean value of model-generated global carbon flux estimates, this equates to an annual flux of 1…
Characterization of a proton pump from Acer pseudoplatanus cell microsomes
1985
Abstract An Acer pseudoplatanus cell microsomal fraction was enriched in ATPase by sedimentation through a sucrose cushion and treatment with Triton X-100. This activity, which reached 0.9 μmol P i min −1 mg −1 protein, was specific for ATP, slightly stimulated by K + , inhibited by orthovanadate and diethylstilbestrol, insensitive to oligomycin and azide, and had a K m - value of 0.51 mM for MgATP. ATP-dependent proton translocation was demonstrated by the ΔpH probe acridine orange. This activity had a optimum at pH 6.5, was substrate specific for ATP, and was strongly dependent on K + . Preparations of plasma membrane ATPase from A. pseudoplatanus cell culture thus posses biochemical prop…
Social flexibility and social evolution in mammals: a case study of the African striped mouse (Rhabdomys pumilio)
2011
Environmental change poses challenges to many organisms. The resilience of a species to such change depends on its ability to respond adaptively. Social flexibility is such an adaptive response, whereby individuals of both sexes change their reproductive tactics facultatively in response to fluctuating environmental conditions, leading to changes in the social system. Social flexibility focuses on individual flexibility, and provides a unique opportunity to study both the ultimate and proximate causes of sociality by comparing between solitary and group-living individuals of the same population: why do animals form groups and how is group-living regulated by the environment and the neuro-en…