222 research outputs found
Spatial and temporal robustness of Sr/CaâSST calibrations in Red Sea corals : evidence for influence of mean annual temperature on calibration slopes
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography and Paleoclimatology 33 (2018): 443-456, doi:10.1029/2017PA003276.Sr/Ca ratios recorded in the aragonite skeleton of massive coral colonies are commonly used to reconstruct seasonalâ to centennialâscale variability in sea surface temperature (SST). While the Sr/Ca paleothermometer is robust in individual colonies, Sr/CaâSST relationships between colonies vary, leading to questions regarding the utility of the proxy. We present biweeklyâresolution calibrations of Sr/Ca from five Porites spp. corals to satellite SST across 10° of latitude in the Red Sea to evaluate the Sr/Ca proxy across both spatial and temporal scales. SST is significantly correlated with coral Sr/Ca at each site, accounting for 69â84% of Sr/Ca variability (P âȘ 0.01). Intercolony variability in Sr/CaâSST sensitivities reveals a latitudinal trend, where calibration slopes become shallower with increasing mean annual temperature. Mean annual temperature is strongly correlated with the biweeklyâresolution calibration slopes across five Red Sea sites (r2 = 0.88, P = 0.05), while also correlating significantly to Sr/CaâSST slopes for 33 Porites corals from across the entire IndoâPacific region (r2 = 0.26, P < 0.01). Although interannual summer, winter, and mean annual calibrations for individual Red Sea colonies are inconsistently robust, combined multicoral calibrations are significant at summer (r2 = 0.53, P âȘ 0.01), winter (r2 = 0.62, P âȘ 0.01), and mean annual time scales (r2 = 0.79, P âȘ 0.01). Our multicoral, multisite study indicates that the Sr/Ca paleothermometer is accurate across both temporal and spatial scales in the Red Sea and also potentially explains for the first time variability in Sr/CaâSST calibration slopes across the IndoâPacific region. Our study provides strong evidence supporting the robustness of the coral Sr/Ca proxy for examining seasonal to multicentury variability in global climate phenomena.Singapore Ministry of Education;
National Research Foundation Singapore Grant Number: NRFFâ2012â03;
U.S. National Science Foundation Grant Number: OCEâ1031288;
King Abdullah University of Science and Technology Grant Numbers: USA 00002, KSA 0001
Metabarcoding analysis of gut microbiota of healthy individuals reveals impact of probiotic and maltodextrin consumption
In a previously published double-blind, placebo-controlled study, we showed that probiotics intake exerted a positive effect on sleep quality and a general improvement across time in different aspects of the profile of mood state, like sadness, anger, and fatigue in 33 healthy individuals. The present work investigates the impact of the probiotic product, constituted of Limosilactobacillus fermentum LF16, Lacticaseibacillus rhamnosus LR06, Lactiplantibacillus plantarum LP01 (all former members of Lactobacillus genus), and Bifidobacterium longum 04, on the gut microbiota composition of the same cohort through a metabarcoding analysis. Both the placebo and probiotic treatments had a significant impact on the microbiota composition. Statistical analysis showed that the microbiota of the individuals could be clustered into three groups, or bacteriotypes, at the baseline, and, inherently, bacterial compositions were linked to different responses to probiotic and placebo intakes. Interestingly, L. rhamnosus and L. fermentum were retrieved in the probiotic-treated cohort, while a bifidogenic effect of maltodextrin, used as placebo, was observed. The present study shed light on the importance of defining bacteriotypes to assess the impact of interventions on the gut microbiota and allowed to reveal microbial components which could be related to positive effects (i.e. sleep quality improvement) to be verified in further studies
Effects of the thermodynamic conditions on the acoustic signature of bubble nucleation in superheated liquids used in dark matter search experiments
[EN] In the framework of the search for dark matter in the form of WIMPs using superheated liquids, a study is conducted to establish a computational procedure aimed at determining how the thermodynamic conditions kept inside a particle detector affect the acoustic signal produced by bubble nucleation. It is found that the acoustic energy injected into the liquid by the growing vapour bubble increases as the liquid pressure is decreased and the superheat degree is increased, the former effect being crucial for the generation of a well-intelligible signal. A good agreement is met between the results of the present study and some experimental data available in the literature for the amplitude of the acoustic signal. Additionally, the higher loudness of the alpha-decay events compared with those arising from neutron-induced nuclear recoils is described in terms of multiple nucleations.The authors are grateful to Walter Fulgione for the valuable discussions and suggestions and for his help in reviewing the manuscript.Ardid RamĂrez, M.; Baschirotto, A.; Burgio, N.; Corcione, M.; Cretara, L.; De Matteis, L.; Felis-Enguix, I.... (2019). Effects of the thermodynamic conditions on the acoustic signature of bubble nucleation in superheated liquids used in dark matter search experiments. The European Physical Journal C. 79(11):1-9. https://doi.org/10.1140/epjc/s10052-019-7485-xS197911W.J. Bolte et al., Nucl. Instr. Meth. Phys. Res. A 577, 569â573 (2007)E. Behnke et al., Astropart. Phys. 90, 85â92 (2017)M. Felizardo et al., E3S Web Conf. 12, 03002 (2016)E. Behnke et al., Phys. Rev. D 88, 021101 (2013)C. Amole et al., Phys. Rev. Lett. 118, 251301 (2017)A. Antonicci et al., Eur. Phys. J. C 77, 752 (2017)D.A. Glaser, Phys. Rev. 87, 655 (1952)F. Seitz, Phys. Fluids 1, 2â13 (1958)E. Behnke et al., Phys. Rev. Lett. 106, 021303 (2011)D.A. Glaser, D.C. Rahm, Phys. Rev. 97, 474â479 (1955)Yu.N. Martynyuk, N.S. Smirnova, Sov. Phys. Acoust. 37, 376â378 (1991)F. Aubin et al., New J. Phys. 10, 103017 (2008)M. Felizardo et al., Nucl. Instr. Meth. Phys. Res. A 589, 72â84 (2008)P.K. Mondal, B.K. Chatterjee, Phys. Lett. A 375, 237â244 (2011)S. Archambault et al., New J. Phys. 13, 043006 (2011)C. Amole et al., Phys. Rev. Lett. 114, 231302 (2015)R. Sarkar et al., Phys. Lett. A 381, 2531â2537 (2017)I.A. Pless, R.J. Plano, Rev. Sci. Instr. 27, 935â937 (1956)D.V. Bugg, Progr. Nucl. Phys. 7, 2â52 (1959)A. Norman, P. Spiegler, Nucl. Sci. Eng. 16, 213â217 (1963)A.G. Tenner, Nucl. Instr. Meth. 22, 1â42 (1963)Ch. Peyrou, In Bubble and Spark Chambers (Academic Press, New York, 1967)C.R. Bell et al., Nucl. Sci. Eng. 53, 458â465 (1974)G. Bruno et al., Eur. Phys. J. C 79, 183 (2019)B.M. Dorofeev, V.I. Volkova, High Temp. 43, 620â627 (2005)L.D. Landau, E.M. Lifshitz, Fluid Mechanics. Course of Theoretical Physics, vol 6, 2nd edn. (Butterworth-Heinemann, Kidlington, Oxford, 1987)Y.Y. Sun, B.T. Chu, R.E. Apfel, J. Comp. Phys. 103, 126â140 (1992)M.S. Plesset, S.A. Zwick, J. Appl. Phys. 25, 493â500 (1954)L.E. Scriven, Chem. Eng. Sci. 10, 1â13 (1959)H.S. Lee, H. Merte, Int. J. Heat Mass Transf. 39, 2427â2447 (1996)A.J. Robinson, R.L. Judd, Int. J. Heat Mass Transf. 47, 5101â5113 (2004)F. dâErrico, Rad. Prot. Dos. 84, 55â62 (1999)B.B. Mikic, W.M. Rohsenow, P. Griffith, Int. J. Heat Mass Transf. 13, 657â666 (1970)P.J. Linstrom, W.G. Mallard (eds.) NIST Chemistry WebBook, NIST-SRD 69 (National Institute of Standards and Technology, Gaithersburg, MD). https://doi.org/10.18434/T4D303M. BarnabĂ©-Heider et al., Nucl. Instr. Meth. Phys. Res. A 555, 184â204 (2005)D.V. Jordan et al., Appl. Rad. Isot. 63, 645â653 (2005
Diploastrea heliopora Sr/Ca and ÎŽ18O records from northeast Luzon, Philippines : an assessment of interspecies coral proxy calibrations and climate controls of sea surface temperature and salinity
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography 32 (2017): 424â438, doi:10.1002/2017PA003098.The Indo-Pacific coral Diploastrea heliopora reveals regional multidecadal- to centennial- scale climate variability using coral carbonate ÎŽ18O (ÎŽ18Oc) as a combined proxy for sea surface temperature (SST) and sea surface salinity (SSS). However, to assess the coral's full potential in resolving climatic events, an independent SST proxy would be more advantageous. We examined both Sr/Ca and ÎŽ18O of Diploastrea against an adjacent Porites lobata core collected from northeast Luzon, Philippines. Winter Sr/Ca data from Diploastrea show a significant correlation to SST (r = â0.41, p < 0.05, (root-mean-square of the residual) RMSR = 0.81°C) and provide a proxy with similar sensitivity as Porites (r = â0.57, p < 0.05, RMSR = 0.62°C). An interspecies SST record is shown to be robust and used for a reconstruction of the Pacific Decadal Oscillation during boreal winter (r = â0.70, p = 0.02). While we were unable to generate a robust Diploastrea ÎŽ18O-SSS calibration at interannual timescale, the freshening trend toward the present, commonly observed in the region, is qualitatively captured in Diploastrea ÎŽ18O. Comparison with Porites ÎŽ18O and instrumental SSS records shows that the magnitude of freshening is consistent between coral species. Wet and dry season Porites ÎŽ18O provide support for the relative influence of El NiñoâSouthern Oscillation events and local precipitation to SSS variability at our site. The multiproxy, multispecies approach of this study further strengthens the evidence for Diploastrea as an alternate climate archive in the Indo-Pacific region and seals its potential in helping resolve less understood global-scale climate phenomena.National Research Foundation Singapore (NRF) Grant Number: NRF-RF2012-0
Saving our marine archives
A concerted effort has begun to gather and preserve archives of marine samples and descriptive data, giving scientists ready access to insights on ancient environments
Biodegradation of herbicide diuron by streptomycetes isolated from soil
The diuron degrading activity of 17 streptomycete strains, obtained from agricultural and non-agricultural soils, was determined in the laboratory. All strains were identified as Streptomyces sp. by phenotypic characteristics and PCR-based assays. The strains were cultivated in liquid medium with diuron (4mgL(-1)) at 25 degrees C for 15 days. Biodegradation activity was deter-mined by high-performance liquid chromatography. The results indicated that all strains were able to degrade diuron, but to different amounts. Twelve strains degraded the herbicide by up to 50% and four of them by up to 70%. Strain A7-9, belonging to S. albidoflavus cluster, was the most efficient organism in the degradation of diuron, achieving 95% degradation after five days of incubation and no herbicide remained after 10 days. Overall, the strains isolated from agricultural soils exhibited higher degradation percentages and rates than those isolated from non-agricultural soils. Given the high degradation activity observed here, the streptomycete strains show a good potential for bioremediation of soils contaminated with diuron. (c) 2006 Elsevier Ltd. All rights reserved.Castillo LĂłpez, MĂ.; Felis Reig, N.; AragĂłn Revuelta, P.; Cuesta Amat, G.; Sabater Marco, C. (2006). Biodegradation of herbicide diuron by streptomycetes isolated from soil. International Biodeterioration and Biodegradation. 58(3-4):196-202. doi:10.1016/j.ibiod.2006.06.020S196202583-
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Pacific Continental Shelf Environmental Assessment (PaCSEA): Seabirds and marine mammals off northern CA, OR, and WA
Interest has increased in developing renewable energy sources to reduce U. S. dependence on oil. Policy makers and resource managers now are considering power generation technologies proposed for development along the Continental Shelf of the U. S. Pacific coast beyond state waters. This region supports abundant populations of seabirds and marine mammals, but comprehensive, multi-seasonal aerial surveys were last conducted two decades ago. Marine spatial planning, including potential site selection for offshore energy development, requires the description and quantification of recent species-specific and community distribution patterns. To relate patterns of seabird abundance to physical and biological characteristics of ocean habitats, we conducted low-elevation aerial seabird surveys during January-February, June-July, and October 2011 & 2012 along parallel strip-transects spanning continental shelf and slope waters from Fort Bragg, CA to Grayâs Harbor, WA. Although effort focused on Federal Waters outside of the 3-nautical mile state boundary, surveys included inshore waters to allow comparisons both within and adjacent to potential renewable energy developments. In the past, environmental analyses of aerial seabird surveys have relied on satellite-derived products of ocean optical properties that are coarse in scale or temporally averaged to produce better spatial coverage. Therefore, in addition to aerial pyrometry to measure sea-surface temperature, we installed an on-board hyperspectral radiometer to collect remotely-sensed reflectance simultaneously with species observations. Herein, we discuss survey methods and describe inter-seasonal trends in abundance and distribution of marine birds and variability in the ocean environment, and introduce aerial hyperspectral radiometry as a potential tool for delineating fine-scale ocean habitat features (fronts and water masses) based on ocean color.KEYWORDS: Marine mammals, Receptors, Seabirds, Marine renewable energy, Wave energy, Wind energ
The Red Sea, Coastal Landscapes, and Hominin Dispersals
This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization
All-sky Search for High-Energy Neutrinos from Gravitational Wave Event GW170104 with the ANTARES Neutrino Telescope
Advanced LIGO detected a significant gravitational wave signal (GW170104)
originating from the coalescence of two black holes during the second
observation run on January 4, 2017. An all-sky high-energy
neutrino follow-up search has been made using data from the ANTARES neutrino
telescope, including both upgoing and downgoing events in two separate
analyses. No neutrino candidates were found within s around the GW
event time nor any time clustering of events over an extended time window of
months. The non-detection is used to constrain isotropic-equivalent
high-energy neutrino emission from GW170104 to less than
erg for a spectrum
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