An objective measure of hyperactivity aspects with compressed webcam video

Background: Objective measures of physical activity are currently not considered in clinical guidelines for the assessment of hyperactivity in the context of Attention-Deficit/Hyperactivity Disorder (ADHD) due to low and inconsistent associations between clinical ratings, missing age-related norm data and high technical requirements. Methods: This pilot study introduces a new objective measure for physical activity using compressed webcam video footage, which should be less affected by age-related variables. A pre-test established a preliminary standard procedure for testing a clinical sample of 39 children aged 6–16 years (21 with a clinical ADHD diagnosis, 18 without). Subjects were filmed for 6 min while solving a standardized cognitive performance task. Our webcam video-based video-activity score was compared with respect to two independent video-based movement ratings by students, ratings of Inattentiveness, Hyperactivity and Impulsivity by clinicians (DCL-ADHS) giving a clinical diagnosis of ADHD and parents (FBB-ADHD) and physical features (age, weight, height, BMI) using mean scores, correlations and multiple regression. Results: Our video-activity score showed a high agreement (r = 0.81) with video-based movement ratings, but also considerable associations with age-related physical attributes. After controlling for age-related confounders, the video-activity score showed not the expected association with clinicians’ or parents’ hyperactivity ratings. Conclusions: Our preliminary conclusion is that our video-activity score assesses physical activity but not specific information related to hyperactivity. The general problem of defining and assessing hyperactivity with objective criteria remains.<br

Biogeochemistry and geomicrobiology of cold-water coral carbonate mounds - lessons learned from IODP Expedition 307

Large mound structures associated with cold-water coral ecosystems commonly occur on the slopes of continental margins, for instance, west of Ireland in the Porcupine Seabight, the Gulf of Cadiz or the Straits of Florida. In the Porcupine Seabight over 1500 mounds of up to 5 km in diameter and 250 m height lie at water depths of 600 to 900 m. The cold-water coral reef ecosystems associated with these structures are considered to be “hotspots” of organic carbon mineralization and microbial systems. To establish a depositional and biogeochemical/diagenetic model for cold-water carbonate mounds, Challenger Mound and adjacent continental slope sites were drilled in May 2005 during IODP Expedition 307. One major objective was to test whether deep sub-surface hydrocarbon flow and enhanced microbial activity within the mound structure was important in producing and stabilizing these sedimentary structures.Drilling results showed that the Challenger mound succession (IODP Site U1317) is 130 to 150 meters thick, and mainly consists of floatstone and rudstone facies formed of fine sediments and cold-water branching corals. Pronounced recurring cycles on the scales of several meters are recognized in carbonate content (up to 70% carbonate) and color reflectance, and are probably associated with Pleistocene glacial-interglacial cycles. A role for methane seepage and subsequent anaerobic oxidation was discounted both as a hard-round substrate for mound initiation and as a principal source of carbonate within the mound succession. A broad sulfate-methane transition (approximately 50 m thick) within the Miocene sediments suggested that the zone of anaerobic oxidation of methane principally occurs below the moundbase. In the mound sediments, interstitial water profiles of sulfate, alkalinity, Mg, and Sr suggested a tight coupling between carbonate diagenesis and low rates of microbial sulfate reduction. Overall organic carbon mineralization within cold-water coral mound appeared to be dominated by low rates of iron- and sulfate-reduction that occur in discrete layers within the mound. This was consistent with distributions of total cell-counts, acetate turnover (Webster et al. 2009) and hydrogenase activity (Soffiento et al. 2009). However, biomarker lipid distributions suggested that the Miocene sediments underlying the mound, into which sulfate is diffusing, as well as the sediments from the non-cold water coral reference site (U1318) contain higher abundances of living microbes. The results obtained from Expedition 307 are consistent with a picture emerging from other biogeochemical studies of cold-water coral mound and reef sites. Unless impacted by some external forcing (e.g. fluid flow or erosion event), the microbial activity in the underlying cold-water coral mound sediments is largely decoupled from the highly diverse, active surface ecosystem

Biogeochemistry of Norwegian cold-water coral reef sediments

Cold-water coral ecosystems may constitute a geologically significant fraction (>1%) of global carbonate production (Lindberg and Mienert, 2005). Thriving cold-water coral reefs are also considered to be hot-spots of diversity and biomass production. Nevertheless, the impacts of these ecosystems on the adjacent sediment and associated geochemical processes including carbonate preservation are poorly understood.Here we present the first data quantifying the biogeochemical processes in modern (post-glacial) cold-water coral reef sediments. This work integrates organoclastic sulfate reduction rates, multi-element pore-water profiles and solid-phase analyses of gravity cores (8 sites at two reefs) retrieved during R/V Polarstern expedition ARKXXII/1a to the mid-Norwegian cold-water coral reefs in June 2007.The reef sediments are comprised of coral fragments embedded in loose silt or clay and biogenic debris (of 0,5 to 3,2 m thickness). The base of the coral-bearing reef sediments consists of highly compacted glacial clays. High carbonate contents (up to 75 %) and low organic carbon contents (~0,5 %) characterize the reef sediments. Porewater Ca2+, Mg2+ and Sr2+ profiles indicate that on-going carbonate precipitation dominates any carbonate dissolution. Overall microbial activity in these sediments is low; measured sulfate reduction rates are less than 1 nmol S cm-3 d-1. Pore-water analyses reveal elevated Fe2+ and Mn2+ concentrations suggesting that Fe and Mn reduction occurs. This may be the result of sulfide reacting with the available reactive iron pool to form Fe-sulfides indicated by the absence of sulfide in the pore water. Fe and Mn reduction may also be attributed to dissimilatory microbial metal reduction. Iron reduction linked to microbial sulfate reduction may enhance diagenetic carbonate precipitation and coral preservation in these sediments as suggested for the older coldwater coral mound systems drilled in IODP Expedition 307 (Ferdelman et al., 2006). Extremely low methane concentrations (<0,5 µM) were found at all depths and sites along the Norwegian margin. This argues against a linkage between coral reef distribution and the appearance of hydrocarbon seepage as formulated by Hovland et al. (1998)

Carbon mineralization and carbonate preservation in modern cold-water coral reef sediments on the Norwegian shelf

Cold-water coral ecosystems are considered hot-spots of biodiversity and biomass production and may be a regionally important contributor to carbonate production. The impact of these ecosystems on biogeochemical processes and carbonate preservation in associated sediments were studied at Røst Reef and Traenadjupet Reef, two modern (post-glacial) cold-water coral reefs on the Mid-Norwegian shelf. Sulfate and iron reduction as well as carbonate dissolution and precipitation were investigated by combining pore-water geochemical profiles, steady state modeling, as well as solid phase analyses and sulfate reduction rate measurements on gravity cores of up to 3.25 m length. Low extents of sulfate depletion and dissolved inorganic carbon (DIC) production, combined with sulfate reduction rates not exceeding 3 nmol S cm−3 d−1, suggested that overall anaerobic carbon mineralization in the sediments was low. These data showed that the coral fragment-bearing siliciclastic sediments were effectively decoupled from the productive pelagic ecosystem by the complex reef surface framework. Organic matter being mineralized by sulfate reduction was calculated to consist of 57% carbon bound in CH2O groups and 43% carbon in -CH2- groups. Methane concentrations were below 1 μM, and failed to support the hypothesis of a linkage between the distribution of cold-water coral reefs and the presence of hydrocarbon seepage. Reductive iron oxide dissolution linked to microbial sulfate reduction buffered the pore-water carbonate system and inhibited acid-driven coral skeleton dissolution. A large pool of reactive iron was available leading to the formation of iron sulfide minerals. Constant pore-water Ca2+, Mg2+ and Sr2+ concentrations in most cores and decreasing Ca2+ and Sr2+ concentrations with depth in core 23–18 GC indicated diagenetic carbonate precipitation. This was consistent with the excellent preservation of buried coral fragments

Gas emissions from five volcanoes in northern Chile, and implications for the volatiles budget of the Central Volcanic Zone

This study performed the first assessment of the volcanic gas output from the Central Volcanic Zone (CVZ) of northern Chile. We present the fluxes and compositions of volcanic gases (H2O, CO2, H2, HCl, HF, and HBr) from five of the most actively degassing volcanoes in this region—Láscar, Lastarria, Putana, Ollagüe, and San Pedro—obtained during field campaigns in 2012 and 2013. The inferred gas plume compositions for Láscar and Lastarria (CO2/Stot = 0.9–2.2; Stot/HCl = 1.4–3.4) are similar to those obtained in the Southern Volcanic Zone of Chile, suggesting uniform magmatic gas fingerprint throughout the Chilean arc. Combining these compositions with our own UV spectroscopy measurements of the SO2 output (summing to ~1800 t d−1 for the CVZ), we calculate a cumulative CO2 output of 1743–1988 t d−1 and a total volatiles output of >20,200 t d−1