Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Provenance study of detrital garnets and rutiles from basaltic pyroclastic rocks of Southern Slovakia (Western Carpathians)

Detrital garnets and rutiles have been recovered from basaltic pyroclastic rocks in the northern part of the Pannonian Basin and characterized using electron probe microanalysis and imaging. All garnets are dominated by the almandine component, except for one sample dominated by spessartine. A total of three garnet groups have been distinguished according to the increased contents of grossular (Group I), pyrope (Group II) and spessartine components (Group III). Compositions of the group I and II garnets with fluctuating Ca- and relatively low Mg contents are consistent with low- to medium-grade metasediments and/or metabasites. Locally increased Mg contents could indicate higher P–T metamorphic overprint. The dominantly metamorphic origin of the Group I and II garnets (composed of >99 % of samples) is also corroborated by chlorite, tourmaline, staurolite, ilmenite and andalusite inclusions. Spessartine-rich garnets (Group III composed of <1 % of samples) could be genetically linked with granitoids. Detrital rutiles invariably plot within the field of metasediments metamorphosed under amphibolite-facies conditions. Possible proximal (subjacent basement sampled by ascending lava) or distal sources (catchment sediments from uplifted Central Carpathian basement) of heavy mineral assemblages are discussed

Doppler shifted Alpha transmitter signals in the conjugate hemisphere: DEMETER spacecraft observations and modeling

International audienceAlpha transmitters are three powerful ground based very low frequency (VLF) transmitters operating at mid-latitudes (geomagnetic latitudes between about 41 and 46 degrees). Their radiation pattern consists of three frequencies (11.9, 12.6, and 14.9 kHz). A signal of a given frequency is radiated for 0.4 s, followed by a 0.2 s pause, then another signal at different frequency is radiated. One radiation pattern cycle takes 3.6 s, being repeated all over again. This is particularly useful, as it allows us to i) analyze propagation of signals at three different frequencies coming from the same place under the same conditions, and ii) determine possible time delays between different frequencies and propagation paths. High resolution wave measurements performed by the low-altitude DEMETER satellite in the geomagnetically conjugate region reveal three simultaneously detected types of signal propagation. These can be readily distinguished from each other by their different Doppler shifts, latitudinal dependences, and dispersions. We use detailed observational analysis and raytracing calculations to explain how these are formed. Specifically, we show that these three signal types can be related to i) ducted propagation between the hemispheres, ii) unducted propagation of originally vertical waves, and iii) unducted propagation of spectrally broadened waves with initial wave normal angles close to the resonance cone

Doppler shifted Alpha transmitter signals in the conjugate hemisphere: DEMETER spacecraft observations and modeling

International audienceAlpha transmitters are three powerful ground based very low frequency (VLF) transmitters operating at mid-latitudes (geomagnetic latitudes between about 41 and 46 degrees). Their radiation pattern consists of three frequencies (11.9, 12.6, and 14.9 kHz). A signal of a given frequency is radiated for 0.4 s, followed by a 0.2 s pause, then another signal at different frequency is radiated. One radiation pattern cycle takes 3.6 s, being repeated all over again. This is particularly useful, as it allows us to i) analyze propagation of signals at three different frequencies coming from the same place under the same conditions, and ii) determine possible time delays between different frequencies and propagation paths. High resolution wave measurements performed by the low-altitude DEMETER satellite in the geomagnetically conjugate region reveal three simultaneously detected types of signal propagation. These can be readily distinguished from each other by their different Doppler shifts, latitudinal dependences, and dispersions. We use detailed observational analysis and raytracing calculations to explain how these are formed. Specifically, we show that these three signal types can be related to i) ducted propagation between the hemispheres, ii) unducted propagation of originally vertical waves, and iii) unducted propagation of spectrally broadened waves with initial wave normal angles close to the resonance cone

Evaluating the influence of lightning generated whistlers on the overall VLF wave intensity detected by a low-altitude spacecraft

International audienceThe influence of lightning generated whistlers on the overall very low frequency (VLF) wave intensity in the Earth's inner magnetosphere is still a subject of discussion. We combine lightning location data and VLF wave intensity measured by a low altitude spacecraft to identify frequency-location intervals where this influence is significant. The World Wide Lightning Location Network (WWLLN) provides a unique data set of times and locations of lightning strokes all around the world. When combined with the wave measurements performed by the DEMETER spacecraft (Sun-synchronous polar orbit, altitude of about 700 km), it allows us to calculate average/median power spectral densities of electric field fluctuations in the frequency range up to 20 kHz distinguished according to the lightning activity level. A comparison of the dependencies obtained for low and high lightning activity levels is then used to determine the influence of lightning generated whistlers. The obtained results are discussed in the frame of a possible relation to the plasmaspheric hiss generation

Evaluating the influence of lightning generated whistlers on the overall VLF wave intensity detected by a low-altitude spacecraft

International audienceThe influence of lightning generated whistlers on the overall very low frequency (VLF) wave intensity in the Earth's inner magnetosphere is still a subject of discussion. We combine lightning location data and VLF wave intensity measured by a low altitude spacecraft to identify frequency-location intervals where this influence is significant. The World Wide Lightning Location Network (WWLLN) provides a unique data set of times and locations of lightning strokes all around the world. When combined with the wave measurements performed by the DEMETER spacecraft (Sun-synchronous polar orbit, altitude of about 700 km), it allows us to calculate average/median power spectral densities of electric field fluctuations in the frequency range up to 20 kHz distinguished according to the lightning activity level. A comparison of the dependencies obtained for low and high lightning activity levels is then used to determine the influence of lightning generated whistlers. The obtained results are discussed in the frame of a possible relation to the plasmaspheric hiss generation

Metamorphic Conditions of Neotethyan Meliatic Accretionary Wedge Estimated by Thermodynamic Modelling and Geothermobarometry (Inner Western Carpathians)

Metamorphic evolution of an accretionary wedge can be constrained by a reconstructed P&ndash;T conditions of the oceanic and continental margin fragments. This paper deals with the metamorphic overprinting of the Inner Western Carpathians (IWC) Meliatic Triassic&ndash;Jurassic paleotectonic units after the closure of the Neotethyan Meliata Basin. Medium to high-pressure and lower temperature conditions were estimated by Perple_X pseudosection modelling, combined with garnet&ndash;phengite, calcite&ndash;dolomite and chlorite thermometers and chlorite&ndash;phengite and phengite barometers. The Late Jurassic subductional burial to a maximum 50 km depth was estimated from the B&ocirc;rka Unit continental margin fragments at 520 &deg;C and 1.55 GPa. This is compatible with the metamorphic peak garnet&ndash;glaucophane&ndash;phengite assemblage of blueschist facies in metabasites. The Jaklovce Unit oceanic fragments were subducted to maximum 35&ndash;40 km at 390&ndash;420 &deg;C and 1.1&ndash;1.3 GPa. Metabasalts and metadolerites contain winchite, riebeckite, actinolite, chlorite, albite, epidote and phengite. A glaucophane-bearing metabasalt recorded an intra-oceanic subduction in blueschist-facies conditions. Rare amphibolite-facies metabasalts of this unit indicate the base of an inferred oceanic crust sliver obducted onto the continental margin wedge. The Meliata Unit oceanic/continental margin flysch calciclastic and siliciclastic metasediments suggest the burial to approximately 15&ndash;20 km at 250&ndash;350 &deg;C and 0.4&ndash;0.6 GPa. This is indicated by a newly formed albite, K-feldspar, illite&ndash;phengite and chlorite associated with quartz and/or calcite and dolomite in these rocks. Magnesio-hastingsite to magnesio-hornblende bearing metagabbro with newly formed metamorphic magnesio-riebeckite and actinolite is an inferred detached Meliatic block tectonically emplaced in a Permian salinar m&eacute;lange in the Silica Nappe hanging wall. Reconstructed P&ndash;T paths indicate variable metamorphic conditions from the medium-pressure to high-pressure subduction of the B&ocirc;rka and Jaklovce units to the Meliata Unit shallow burial in an accretionary wedge during Late Jurassic to Early Cretaceous Meliaticum evolution. M&eacute;lange blocks of Meliaticum incorporate different juxtaposed Meliatic paleotectonic units exposed in nappe outliers overlying the IWC Gemeric and Veporic superunits