460 research outputs found
Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores)
The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate-production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out in the southern Faial Channel to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth.
Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth.
Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (â631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found â inversely to bioerosion â on down-facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on down-facing substrates.
In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, â54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory
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Laser surface cleaning
Decontamination of contaminated metal and material recycle, two of 31 priority needs identified by the D&D focus group, are the most promising applications for laser ablation within the DOE complex. F2 Associates has developed a robotic laser ablation system that is capable of high contamination rates, waste volume reduction, surface pore cleaning, and real-time characterization of materials. It is being demonstrated that this system will be the most cost-effective technology for metal decontamination and material recycle
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Nonpetroleum mobility fuels and military-energy self-sufficiency
Nonpetroleum hydrocarbon fuels will likely serve as transition fuels for a few decades after petroleum sources become scarce. But nonpetroleum hydrocarbon fuels are ultimately either nonrenewable (e.g., coal and oil shale synfuels) or are inefficient to produce. Nuclear sources (supplemented by solar, geothermal, etc., as available) for electric power generation and hydrogen production provide a combination that can be used for military energy needs including mobility fuels, namely liquid hydrogen. This approach can give the military energy self-sufficiency for stationary needs as well as ground vehicles, ships, and aircraft. System integration concepts are discussed, and concepts for a methodology to evaluate source-to-use pathways for different classes of military bases are outlined
Sr/Ca ratios in cold-water corals - a âlow-resolutionâ temperature archive?
One of the basic data to understand global change and past global changes is the measurement and the reconstruction of temperature of marine water masses. E.g. seawater temperature controls the density of seawater and in combination with salinity is the major driving force for the oceans circulation system. Geochemical investigations on cold-water corals Lophelia pertusa and Desmophyllum cristagalli indicated the potential of these organisms as high-resolution archives of environmental parameters from intermediate and deeper water masses (Adkins and Boyle 1997). Some studies tried to use cold-water corals as a high-resolution archive of temperature and salinity (Smith et al. 2000, 2002; Blamart et al. 2005; Lutringer et al. 2005). However, the fractionation of stable isotopes (delta18O and delta13C) and element ratios (Sr/Ca, Mg/Ca, U/Ca) are strongly influenced by vital effects (Shirai et al. 2005; Cohen et al. 2006), and difficult to interpret. Nevertheless, ongoing studies indicate the potential of a predominant temperature dependent fractionation of distinct isotopes and elements (e.g. Li/Ca, Montagna et al. 2008; U/Ca, Mg/Ca, delta18O, LĂČpez Correa et al. 2008; delta88/86Sr, RĂŒggeberg et al. 2008).Within the frame of DFG-Project TRISTAN and PalĂ€o-TRISTAN (Du 129/37-2 and 37-3) we investigated live-collected specimens of cold-water coral L. pertusa from all along the European continental margin (Northern and mid Norwegian shelves, Skagerrak, Rockall and Porcupine Bank, Galicia Bank, Gulf of Cadiz, Mediterranean Sea). These coral samples grew in waters characterized by temperatures between 6°C and 14°C. Electron Microprobe investigations along the growth direction of individual coral polyps were applied to determine the relationship between the incorporation of distinct elements (Sr, Ca, Mg, S). Cohen et al. (2006) showed for L.pertusa from the Kosterfjord, Skagerrak, that ~25% of the coralâs Sr/Ca ratio is related to temperature, while 75% are influenced by the calcification rate of the organism. However, the Sr/Ca-temperature relation of our L. pertusa specimens suggest, that mean values are more reliable for temperature reconstruction along a larger temperature range than local high-resolution investigations. Additionally, our results plot on same line of Sr/Ca-temperature relationship like tropical corals indicating a similar behaviour of element incorporation during calcification
Face selective patches in marmoset frontal cortex
© 2020, The Author(s). In humans and macaque monkeys, socially relevant face processing is accomplished via a distributed functional network that includes specialized patches in frontal cortex. It is unclear whether a similar network exists in New World primates, who diverged ~35 million years from Old World primates. The common marmoset is a New World primate species ideally placed to address this question given their complex social repertoire. Here, we demonstrate the existence of a putative high-level face processing network in marmosets. Like Old World primates, marmosets show differential activation in anterior cingulate and lateral prefrontal cortices while they view socially relevant videos of marmoset faces. We corroborate the locations of these frontal regions by demonstrating functional and structural connectivity between these regions and temporal lobe face patches. Given the evolutionary separation between macaques and marmosets, our results suggest this frontal network specialized for social face processing predates the separation between Platyrrhini and Catarrhini
Antidiabetic Effects of Chamomile Flowers Extract in Obese Mice through Transcriptional Stimulation of Nutrient Sensors of the Peroxisome Proliferator-Activated Receptor (PPAR) Family
Given the significant increases in the incidence of metabolic diseases,
efficient strategies for preventing and treating of these common disorders are
urgently needed. This includes the development of phytopharmaceutical products
or functional foods to prevent or cure metabolic diseases. Plant extracts from
edible biomaterial provide a potential resource of structurally diverse
molecules that can synergistically interfere with complex disorders. In this
study we describe the safe application of ethanolic chamomile (Matricaria
recutita) flowers extract (CFE) for the treatment and prevention of type 2
diabetes and associated disorders. We show in vitro that this extract
activates in particular nuclear receptor peroxisome proliferator-activated
receptor gamma (PPARÎł) and its isotypes. In a cellular context, in human
primary adipocytes CFE administration (300 ”g/ml) led to specific expression
of target genes of PPARÎł, whereas in human hepatocytes CFE-induced we detected
expression changes of genes that were regulated by PPARα. In vivo treatment of
insulin-resistant high-fat diet (HFD)-fed C57BL/6 mice with CFE (200 mg/kg/d)
for 6 weeks considerably reduced insulin resistance, glucose intolerance,
plasma triacylglycerol, non-esterified fatty acids (NEFA) and LDL/VLDL
cholesterol. Co-feeding of lean C57BL/6 mice a HFD with 200 mg/kg/d CFE for 20
weeks showed effective prevention of fatty liver formation and hepatic
inflammation, indicating additionally hepatoprotective effects of the extract.
Moreover, CFE treatment did not reveal side effects, which have otherwise been
associated with strong synthetic PPAR-targeting molecules, such as weight
gain, liver disorders, hemodilution or bone cell turnover. Taken together,
modulation of PPARs and other factors by chamomile flowers extract has the
potential to prevent or treat type 2 diabetes and related disorders
Coldâwater coral assemblages on vertical walls from the Northeast Atlantic
Aim
In this study, we assess patterns of coldâwater coral assemblages observed on deepâsea vertical walls. Similar to their shallowâwater counterparts, vertical and overhanging walls in the deep sea can host highly diverse communities, but because of their geometry, these habitats are generally overlooked and remain poorly known. These vertical habitats are however of particular interest, because they can protect vulnerable coral ecosystems from trawling activities. As such, it is important to understand their ecology and assess their global importance.
Location
Vertical walls on complex geomorphic features, in particular walls of the Rockall Bank Slope Failure Escarpment, Whittard and Explorer Canyons, Northeast Atlantic.
Methods
Video analysis of remotely operated vehicle transects carried out at five sites is used to investigate differences in species composition and diversity across walls and to compare those to nearby coldâwater coral sites on flat terrain. A highâresolution photogrammetric reconstruction is further employed to examine whether wall complexity plays a role in promoting niche differentiation at very fine spatial scales.
Results
The investigated walls showed differences in species assemblage both across walls and in comparison to flat sites, with the fineâscale heterogeneity engendered by walls allowing niche differentiation between closely related taxa.
Main Conclusions
Vertical walls represent an important coldâwater coral habitat with differences in species composition across walls within a region, illustrating their role in driving diversity patterns. Based on publicly available bathymetric datasets and a catalogue of broadâscale terrain features, globally over 8,000 features are likely to have vertical walls and coldâwater corals, which highlight the need to consider deepâsea vertical habitats in current conservation efforts
Data compression for the First G-APD Cherenkov Telescope
The First Geiger-mode Avalanche photodiode (G-APD) Cherenkov Telescope (FACT)
has been operating on the Canary island of La Palma since October 2011.
Operations were automated so that the system can be operated remotely. Manual
interaction is required only when the observation schedule is modified due to
weather conditions or in case of unexpected events such as a mechanical
failure. Automatic operations enabled high data taking efficiency, which
resulted in up to two terabytes of FITS files being recorded nightly and
transferred from La Palma to the FACT archive at ISDC in Switzerland. Since
long term storage of hundreds of terabytes of observations data is costly, data
compression is mandatory. This paper discusses the design choices that were
made to increase the compression ratio and speed of writing of the data with
respect to existing compression algorithms.
Following a more detailed motivation, the FACT compression algorithm along
with the associated I/O layer is discussed. Eventually, the performances of the
algorithm is compared to other approaches.Comment: 17 pages, accepted to Astronomy and Computing special issue on
astronomical file format
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