Osmotrophy of dissolved organic carbon by coccolithophores in darkness

• The evolutionary and ecological story of coccolithophores poses questions about their heterotrophy, surviving darkness after the end-Cretaceous asteroid impact as well as survival in the deep ocean twilight zone. Uptake of dissolved organic carbon might be an alternative nutritional strategy for supply of energy and carbon molecules. • Using long-term batch culture experiments, we examined coccolithophore growth and maintenance on organic compounds in darkness. Radiolabeled experiments were performed to study the uptake kinetics. Pulse-chase experiments were used to examine the uptake into unassimilated, exchangeable pools versus assimilated, non-exchangeable pools. • We found that coccolithophores were able to survive and maintain their metabolism for up to 30 days in darkness, accomplishing about one cell division. The concentration dependence for uptake was similar to the concentration dependence for growth in Cruciplacolithus neochelis, suggesting that it was taking up carbon compounds and immediately incorporating them into biomass. We recorded net incorporation of radioactivity into the particulate inorganic fraction. • We conclude that osmotrophy provides nutritional flexibility and supports long-term survival in light levels well below threshold for photosynthesis. The incorporation of dissolved organic matter into particulate inorganic carbon, raises fundamental questions about the role of the alkalinity pump and the alkalinity balance in the sea

Un support IDM pour l'architecture d'entreprise dans un contexte industriel : l'exemple du framework TEAP

National audienceL'application de l'Ingénierie Dirigée par les Modèles (IDM) est souvent réservée aux processus de génie logiciel (par exemple, spécification, génération de code, maintenance, rétro-ingénierie, évolution). Cependant, elle peut aussi être bénéfique pour des initiatives davantage orientées métier ou liées à la prise de décisions stratégiques, telles que l'Architecture d'Entreprise (AE). L'AE est le processus de traduction de la vision métier/stratégie d'une entreprise en un changement effectif, via la description de son état présent et futur (par exemple, concernant son système d'information). Même si différentes approches ont déjà proposé plusieurs sortes de méthodes et d'outillages pour l'AE dans une entreprise, il n'existe pas véritablement à l'heure actuelle de framework IDM intégré combinant fédération de données d'AE, adaptabilité du standard de représentation et support pour des points de vue multiples. Le présent article rapporte notre expérience en cours de construction du framework IDM TEAP (basé sur le standard TOGAF et l'outillage SmartEA) visant notamment à traiter ces trois défis dans un contexte industriel d'AE

Coccolithophore counts from polarized microscopy birefringence measurements of samples collected in the Northwest Atlantic during R/V Endeavor cruise EN616 in July 2018

Dataset: Coccolithophore birefringence from polarized microscopyThis dataset presents polarized microscopy-derived concentration data for coccolithophores and detached coccoliths in samples collected from stations in the Northwest Atlantic during R/V Endeavor cruise EN616 in July 2018. Counts are based on image analysis of dark-field, cross-polarized views of filtered particulate matter. These counts take advantage of the birefringence property of calcium carbonate (particulate inorganic carbon) that it rotates the plane of linearly polarized incident light by 90 degrees. Incident light directed upwards, towards the microscope slide, is polarized 90 degrees with a linear polarizer. Particles are viewed from above the slide, through a second, linear polarizer filter held between the microscope stage and the camera which only accepts light that is polarized orthogonal to the lower polarizer. Calcium carbonate particles in the beam appear as bright dots of light. Image analysis software then analyzes the pattern of birefringence and enumerates only those particles with size and shape of coccolithophores or detached coccoliths. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/887863NSF Division of Ocean Sciences (NSF OCE) OCE-163574

Hyperspectral optical absorption closure experiment in complex coastal waters

Accurate measurements of absorption data are required for the development and validation of inversion algorithms for upcoming hyperspectral ocean color imaging sensors, such as the NASA Phytoplankton, Aerosol, Cloud, and ocean Ecosystem mission. This study aims to provide uncertainty estimates associated with leading approaches to measure hyperspectral absorption coefficients in complex coastal waters. Absorption spectra were collected at 12 different stations, all located in the Indian River Lagoon, Florida, USA, between 09 January 2017 and 13 January 2017. Measurements included spectral absorption coefficients in the visible range (400–700 nm) associated with dissolved, a CDOM, total particulate, a p, and total nonwater, a nw, fractions, and were made both in situ and from discrete samples. Discrete sample approaches included dual-beam spectrophotometer, liquid waveguide capillary cell, point-source integrating cavity absorption meter (PSICAM) for dissolved matter absorption samples, and quantitative filter technique ICAM measurements and the dual-beam spectrophotometer with center-mounted integrating sphere filter pad technique, while the Turner Designs ICAM, and WET Labs AC-s, and AC-9 instruments were used to determine absorption coefficients in situ. The Gershun approach, determining absorption from measurement of the irradiance quartet with respect to depth was also assessed in situ. Measurement uncertainties and relative accuracies were quantified for each of these approaches. Results showed generally strong agreements between different discrete sample methods, with average percent absolute error %δ abs < 7% for a CDOM and < 9% for a p. In situ approaches showed higher variability and reduced accuracy. For a nw, %δ abs deviation relative to PSICAM data was on average 12% to 20%. Results help identify remaining technological gaps and need for improvements in the different absorption measurement approaches

Trans-cerebral HCO3- and PCO2 exchange during acute respiratory acidosis and exercise-induced metabolic acidosis in humans

This study investigated trans-cerebral internal jugular venous-arterial bicarbonate ([HCO(3)(−)]) and carbon dioxide tension (PCO(2)) exchange utilizing two separate interventions to induce acidosis: 1) acute respiratory acidosis via elevations in arterial PCO(2) (PaCO(2)) (n = 39); and 2) metabolic acidosis via incremental cycling exercise to exhaustion (n = 24). During respiratory acidosis, arterial [HCO(3)(−)] increased by 0.15 ± 0.05 mmol ⋅ l(−1) per mmHg elevation in PaCO(2) across a wide physiological range (35 to 60 mmHg PaCO(2); P < 0.001). The narrowing of the venous-arterial [HCO(3)(−)] and PCO(2) differences with respiratory acidosis were both related to the hypercapnia-induced elevations in cerebral blood flow (CBF) (both P < 0.001; subset n = 27); thus, trans-cerebral [HCO(3)(−)] exchange (CBF × venous-arterial [HCO(3)(−)] difference) was reduced indicating a shift from net release toward net uptake of [HCO(3)(−)] (P = 0.004). Arterial [HCO(3)(−)] was reduced by −0.48 ± 0.15 mmol ⋅ l(−1) per nmol ⋅ l(−1) increase in arterial [H(+)] with exercise-induced acidosis (P < 0.001). There was no relationship between the venous-arterial [HCO(3)(−)] difference and arterial [H(+)] with exercise-induced acidosis or CBF; therefore, trans-cerebral [HCO(3)(−)] exchange was unaltered throughout exercise when indexed against arterial [H(+)] or pH (P = 0.933 and P = 0.896, respectively). These results indicate that increases and decreases in systemic [HCO(3)(−)] – during acute respiratory/exercise-induced metabolic acidosis, respectively – differentially affect cerebrovascular acid-base balance (via trans-cerebral [HCO(3)(−)] exchange)

MDE Support for Enterprise Architecture in an Industrial Context: the TEAP Framework Experience

International audienceModel Driven Engineering (MDE) is often applied to support software engineering processes (i.e., from reverse to forward engineering, including maintenance and/or evolution tasks). However, as promoted by the Model Driven Organization (MDO) initiative, it can also be relevant in more business-oriented and strategic decision-making activities such as Enterprise Architecture (EA). EA is the process of translating business vision and strategy into effective change by better describing the enterprise's future state and thus enable its evolution. Even if several approaches have already proposed different kinds of support to deal with the company's EA, an integrated MDE framework combining EA data federation, EA standard adaptation and multiple viewpoint support is still missing. This paper reports on our ongoing experience of building the TEAP MDE framework (based on the TOGAF standard and SmartEA tooling) notably addressing these three challenges in an industrial EA context

Performance and design evaluation of the RAID-II storage server

RAID-II is a high-bandwidth, network-attached storage server designed and implemented at the University of California at Berkeley. In this paper, we measure the performance of RAID-II and evaluate various architectural decisions made during the design process. We first measure the end-to-end performance of the system to be approximately 20 MB/s for both disk array reads and writes. We then perform a bottleneck analysis by examining the performance of each individual subsystem and conclude that the disk subsystem limits performance. By adding a custom interconnect board with a high-speed memory and bus system and parity engine, we are able to achieve a performance speedup of 8 to 15 over a comparative system using only off-the-shelf hardware.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44815/1/10619_2005_Article_BF01266330.pd

Long-term effects of high intensity resistance and endurance exercise on plasma leptin and ghrelin in overweight individuals:the RESOLVE Study

International audienceThe objective of this study was to evaluate the effects of high-intensity resistance and endurance exercise on body composition and plasma leptin and ghrelin concentrations in overweight individuals. One hundred participants were randomly assigned to 3 exercise interventions: high-resistance–low-aerobic exercise (Re), low-resistance–high-aerobic exercise (rE), low-resistance–low-aerobic exercise (re). Interventions began with 3 weeks of residential supervision (phase 1) after which participants had to manage the physical activity programs individually (phase 2). Body composition and plasma variables were measured at baseline and after phase 1 as well as after 3, 6, and 12 months. Significant decreases in body weight and fat were observed after phase 1 (p < 0.001) and continued at a lower rate for up to 3 months and then remained stable for the rest of the protocol. Once a body weight plateau was reached, body fat loss after the Re and rE conditions exceeded the fat loss observed in the re condition by 1.5–2 kg (p < 0.05). Leptin was significantly decreased after day 21 and month 3 (p < 0.001) and remained stable for the rest of the study. Ghrelin was significantly increased after day 21 and month 3 (p < 0.001) and returned to a level comparable to baseline between month 6 and 12 when body weight and fat had reached a plateau. In conclusion, this study reinforces the idea that an increase in exercise intensity may accentuate body fat loss before the occurrence of a body weight plateau. Resistance to further fat loss was accompanied by a decrease in plasma leptin and an increase in plasma ghrelin

A global compilation of coccolithophore calcification rates

The biological production of calcium carbonate (CaCO3), a process termed calcification, is a key term in the marine carbon cycle. A major planktonic group responsible for such pelagic CaCO3 production (CP) is the coccolithophores, single-celled haptophytes that inhabit the euphotic zone of the ocean. Satellite-based estimates of areal CP are limited to surface waters and open-ocean areas, with current algorithms utilising the unique optical properties of the cosmopolitan bloom-forming species Emiliania huxleyi, whereas little understanding of deep-water ecology, optical properties or environmental responses by species other than E. huxleyi is currently available to parameterise algorithms or models. To aid future areal estimations and validate future modelling efforts we have constructed a database of 2765 CP measurements, the majority of which were measured using 12 to 24 h incorporation of radioactive carbon (14C) into acid-labile inorganic carbon (CaCO3). We present data collated from over 30 studies covering the period from 1991 to 2015, sampling the Atlantic, Pacific, Indian, Arctic and Southern oceans. Globally, CP in surface waters ( < 20 m) ranged from 0.01 to 8398 µmol C m−3 d−1 (with a geometric mean of 16.1 µmol C m−3 d−1). An integral value for the upper euphotic zone (herein surface to the depth of 1 % surface irradiance) ranged from  < 0.1 to 6 mmol C m−2 d−1 (geometric mean 1.19 mmol C m−2 d−1). The full database is available for download from PANGAEA at https://doi.org/10.1594/PANGAEA.888182