89 research outputs found

    ForestGEO Dead Wood Census Protocol

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    After stems die, the wood persists in the ecosystem, either as standing deadwood or woody debris on the ground. Deadwood plays an important role in forest ecosystems, providing significantly different substrate, nutrient source, and microclimate to seedlings as well as habitat to vertebrates and invertebrates. Measurements of dead material on the forest floor can be used to more completely estimate biomass, carbon pools, and carbon fluxes. These methods continue the philosophy of the ForestGEO demography data by tracking the status of individual woody stems after mortality and thereby extending observations to the entire period each woody stem exists in the forest

    Titanium dioxide nanoparticles enhance mortality of fish exposed to bacterial pathogens

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    Nano-TiO2 is immunotoxic to fish and reduces the bactericidal function of fish neutrophils. Here, fathead minnows (Pimephales promelas) were exposed to low and high environmentally relevant concentration of nano-TiO2 (2 ng g−1 and 10 μg g−1 body weight, respectively), and were challenged with common fish bacterial pathogens, Aeromonas hydrophila or Edwardsiella ictaluri. Pre-exposure to nano-TiO2 significantly increased fish mortality during bacterial challenge. Nano-TiO2 concentrated in the kidney and spleen. Phagocytosis assay demonstrated that nano-TiO2 has the ability to diminish neutrophil phagocytosis of A. hydrophila. Fish injected with TiO2 nanoparticles displayed significant histopathology when compared to control fish. The interplay between nanoparticle exposure, immune system, histopathology, and infectious disease pathogenesis in any animal model has not been described before. By modulating fish immune responses and interfering with resistance to bacterial pathogens, manufactured nano-TiO2 has the potential to affect fish survival in a disease outbreak

    The mysteries of mammatus clouds: Observations and formation mechanisms

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    Mammatus clouds are an intriguing enigma of atmospheric fluid dynamics and cloud physics. Most commonly observed on the underside of cumulonimbus anvils, mammatus also occur on the underside of cirrus, cirrocumulus, altocumulus, altostratus, and stratocumulus, as well as in contrails from jet aircraft and pyrocumulus ash clouds from volcanic eruptions. Despite their aesthetic appearance, mammatus have been the subject of few quantitative research studies. Observations of mammatus have been obtained largely through serendipitous opportunities with a single observing system (e.g., aircraft penetrations, visual observations, lidar, radar) or tangential observations from field programs with other objectives. Theories describing mammatus remain untested, as adequate measurements for validation do not exist because of the small distance scales and short time scales of mammatus. Modeling studies of mammatus are virtually nonexistent. As a result, relatively little is known about the environment, formation mechanisms, properties, microphysics, and dynamics of mammatus. This paper presents a review of mammatus clouds that addresses these mysteries. Previous observations of mammatus and proposed formation mechanisms are discussed. These hypothesized mechanisms are anvil subsidence, subcloud evaporation/sublimation, melting, hydrometeor fallout, cloud-base detrainment instability, radiative effects, gravity waves, Kelvin-Helmholtz instability, Rayleigh-Taylor instability, and Rayleigh-Bénard-like convection. Other issues addressed in this paper include whether mammatus are composed of ice or liquid water hydrometeors, why mammatus are smooth, what controls the temporal and spatial scales and organization of individual mammatus lobes, and what are the properties of volcanic ash clouds that produce mammatus? The similarities and differences between mammatus, virga, stalactites, and reticular clouds are also discussed. Finally, because much still remains to be learned, research opportunities are described for using mammatus as a window into the microphysical, turbulent, and dynamical processes occurring on the underside of clouds. © 2006 American Meteorological Society

    Temporada coreográfica primavera 1974

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    Programa de la Temporada coreogràfica de la primavera de 1974. El Ballet del Teatre Nacional de Belgrad era dirigit per M. Jovanovic, el director d'orquestra va ser D. Miladinovic i el pianista acompanyant fou M. Zamurovic. Van estrenar "Ana Karenina", amb música de R. Schredin, "Golem", amb música de F. Burt i "Bacchus et Arianne" amb música d'A. Roussel. D. Parlic va ser el coreògraf de totes elles. També es van representar "Simfonia en do" amb música de G. Bizet i coreografia de D. Parlic, "Danses Polovtsianes d'El príncep Ígor" amb música d'A. Borodin i coreografia de M. Fokine adaptada per Anica Prelie, i passos a dos de "Don Quixote" amb música de L. Minkus, "El llac dels cignes" i "El trencanous" amb música de P. I. TxaikovskiEl Ballet del Teatre de l'òpera alemanya del Rhin estava dirigit per E. Walter, que també n'era coreògraf. L'orquestra va ser dirigida per R. Schaub, R. Kubik i A. Quennet i els pianistes W. Riddlespurger i A. Roth-Schutzbach. Van estrenar una nova versió de "Romeo i Julieta" amb música de S. Prokofiev i coreografia d'E. Walter, "Apollon Musagette" amb música d'I. Stravinsky i coreografia de G. Balanchine, "La mort i la donzella" amb música de F. Schubert i coreografia d'E. Walter, i "Jeux", amb música de C. Debussy i coreografia d'E. Walter. També van dansar les reposicions de "Giselle" amb música d'Adolphe Adam amb coreografia de R. Mazalova i E. Walter, "El mandarí meravellós" amb música de Bela Bartók i coreografia d'E. Walter, i "Daphnis et Chloe" amb música de M. Ravel i coreografia d'E. Walte

    Carbon carrying capacity in primary forests shows potential for mitigation achieving the European Green Deal 2030 target

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    13 Pág.Carbon accounting in the land sector requires a reference level from which to calculate past losses of carbon and potential for gains using a stock-based target. Carbon carrying capacity represented by the carbon stock in primary forests is an ecologically-based reference level that allows estimation of the mitigation potential derived from protecting and restoring forests to increase their carbon stocks. Here we measured and collated tree inventory data at primary forest sites including from research studies, literature and forest inventories (7982 sites, 288,262 trees, 27 countries) across boreal, temperate, and subtropical Global Ecological Zones within Europe. We calculated total biomass carbon stock per hectare (above- and below-ground, dead biomass) and found it was 1.6 times larger on average than modelled global maps for primary forests and 2.3 times for all forests. Large trees (diameter greater than 60 cm) accounted for 50% of biomass and are important carbon reservoirs. Carbon stock foregone by harvesting of 12–52% demonstrated the mitigation potential. Estimated carbon gain by protecting, restoring and ongoing growth of existing forests equated to 309 megatons carbon dioxide equivalents per year, additional to, and higher than, the current forest sink, and comparable to the Green Deal 2030 target for carbon dioxide removals.We thank the many people involved with the collection and provision of the site data and recognise the significant resources, people and time required to collect this invaluable data. The research for the synthesis, analysis and writing (H.K., Z.K., S.H., B.M.) was supported by a grant from a charitable organisation which neither seeks nor permits publicity for its efforts. The funder had no involvement in the study design, results or publication of the paper. Site data from Spain was funded by the Spanish Ministry of Science, Innovation and Universities [AGL2016-76769-C2-2-R]. C.P.C. was supported by the Spanish Ministry of Science and Innovation [RYC2018-024939-I]. J.A.M.V. was supported by the Ramón Areces Foundation Grants for Postdoctoral Studies. Contribution of D.A., K.K. and P.S. as well as data collection and processing from Czech natural forests was supported by Czech Science Foundation, project no. 24-11119S. D.M.-B. was funded by projects AGL2015-73190-JIN, PID2019-110273RB-I00 and contract RYC-2017-23389 by the Spanish Ministry of Science and Innovation MCIN/AEI. V.B. and I.D. were supported by the FORCLIMIT project funded in the frame of the ERA-NET FACCE ERA-GAS and with national support from Romanian National Authority for Scientific Research and Innovation, CCCDI \u2013 UEFISCDI [grant number 82/2017]. FACCE ERA-GAS has received funding from the European Union\u2019s Horizon 2020 research and innovation programme [grant agreement 696356. T.Z. was funded by The WWF Bulgaria through the project IKEA \u2116 9E0710.05 and by The National Roadmap for Research Infrastructure (2020-2027), Ministry of Education and Science of Republic of Bulgaria, through agreements No DO1-405/18.12.2020 and DO1-163/28.07.2022 (LTER-BG). L.D. was funded by the project of the National Research, Development and Innovation Office NKFIH K 131837. T.N. received support from the Slovenian Research Agency (Project No. J4-1765). For additional assistance with site data, we thank Dr. Ra\u00FAl Sanchez-Salguero and Dr. Andrea Hevia for evaluating the age in the dendrochronological samples in Spain, and Nesibe K\u00F6se, Mehmet Do\u011Fan, Daniel Bishop, Marco Mina, Timothy Thrippleton, Neil Pederson, Guillermo Gea-Izquierdo and Macarena F\u00E9rriz for their help during fieldwork, and Cengiz Cihan and the Turkish General Directorate of Forestry (OGM) in Bor\u00E7ka (Artvin) for their assistance in the field in Turkey.Peer reviewe

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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