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  • 1
    Publikationsdatum: 2023-01-25
    Beschreibung: Large, rarely mobile boulders are observed globally in mountainous bedrock channels. Recent studies suggest that high concentrations of boulders could be associated with channel morphological adjustment. However, a process‐based understanding of large boulder effects on channel morphology is limited, and data are scarce and ambiguous. Here, we develop a theory of steady‐state channel width and slope as a function of boulder concentration. Our theory assumes that channel morphology adjusts to maintain two fundamental mass balances: (a) grade, in which the channel transports the same sediment flux downstream despite boulders acting as roughness elements and (b) bedrock erosion, by which the channel erodes at the background tectonic uplift rate. Model predictions are normalized by a reference, boulder‐free channel width and slope, accounting for variations due to sediment supply, discharge, and lithology. Models are tested against a new data set from the Liwu River, Taiwan, showing steepening and widening with increasing boulder concentration. Whereas one of the explored mechanisms successfully explains the observed steepening trend, none of the models accuratly account for the observed width variability. We propose that this contrast arises from different adjustment timescales: while sediment bed slope adjusts within a few floods, width adjustment takes a much longer time. Overall, we find that boulders represent a significant perturbation to fluvial landscapes. Channels tend to respond by forming a new morphology that differs from boulder‐free channels. The general approach presented here can be further expanded to explore the role of other hydrodynamic effects associated with large, rarely mobile boulders.
    Beschreibung: Plain Language Summary: Large boulders are a significant feature in mountainous landscapes. Recent studies suggested that boulders residing in rivers interfere with the flow and sediment transport, forcing their geometry, specifically width and slope, to change. Our ability to understand and predict such changes is challenged by scarce field data and a general lack of models capable of explaining the processes underlying channel geometry adjustment in the presence of boulders. Here, we develop a theory and several models for the variation of channel width and slope as with channel boulder coverage. Our theory builds on the assumption that the geometry of boulder‐bed channels evolves to a new configuration to maintain steadiness of erosion rate and sediment transport. Predictions from the various models are tested against data from the steep Liwu River in Taiwan. These data show that width and slope increase with more boulders. We find that channel slope increases to overcome the greater resistance to sediment transport due to the boulders. In contrast, the scattered nature of the width data and the overall models inability to explain width variability likely reflect a longer adjustment period for width than for slope. This study demonstrates the important role of boulders in shaping landscapes.
    Beschreibung: Key Points: We develop a theory for steady‐state reach‐scale channel morphology responding to large, rarely mobile boulders in bedrock rivers. Predictions of boulder‐bed channel width and slope are derived based on grade equilibrium and bedrock erosional balance. Theory is tested against new data from the Liwu River, Taiwan, showing steepening and widening with increasing boulder concentration.
    Beschreibung: Israel Science Foundation http://dx.doi.org/10.13039/501100003977
    Beschreibung: NSF‐BSF
    Beschreibung: https://zenodo.org/record/6371224#.YjdBkOpByUk
    Schlagwort(e): ddc:551.3 ; boulders ; slope ; width ; bedrock erosion ; sediment transport ; grade
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 1992-01-01
    Print ISSN: 0883-6353
    Digitale ISSN: 1520-6548
    Thema: Klassische Archäologie , Geologie und Paläontologie
    Publiziert von Wiley
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2014-07-01
    Print ISSN: 0031-0182
    Digitale ISSN: 1872-616X
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Elsevier
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    facet.materialart.
    Unbekannt
    CLACSO
    Publikationsdatum: 2024-03-29
    Beschreibung: Esta publicación reúne artículos que dan cuenta de los distintos procesos que han atravesado las prácticas feministas en los sindicatos argentinos en el contexto del auge del movimiento feminista. Se analiza cómo este movimiento ha atravesado la agenda de los sindicatos en sus múltiples dimensiones y los cambios que se han dado en los niveles de dirección; así como las experiencias laborales y sindicales cotidianas de las y los trabajadores en sus propios puestos de trabajo, allí donde el género se cruza directamente con la clase, la raza y el lugar de procedencia. Asimismo, se pueden reconocer en sus páginas experiencias de prácticas políticas que visibilizan y reconocen demandas feministas entre las trabajadoras, así como sus desafíos a futuro.
    Schlagwort(e): Feminist & Women's Studies ; Labor & Employment Relations ; thema EDItEUR::J Society and Social Sciences::JB Society and culture: general::JBS Social groups, communities and identities::JBSF Gender studies, gender groups::JBSF1 Gender studies: women and girls::JBSF11 Feminism and feminist theory ; thema EDItEUR::K Economics, Finance, Business and Management::KC Economics::KCF Labour / income economics
    Sprache: Spanisch
    Format: image/jpeg
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2022-05-27
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Fanelli, E., Bianchelli, S., Foglini, F., Canals, M., Castellan, G., Guell-Bujons, Q., Galil, B., Goren, M., Evans, J., Fabri, M.-C., Vaz, S., Ciuffardi, T., Schembri, P. J., Angeletti, L., Taviani, M., & Danovaro, R. Identifying priorities for the protection of deep Mediterranean Sea ecosystems through an integrated approach. Frontiers in Marine Science, 8, (2021): 698890, https://doi.org/10.3389/fmars.2021.698890.
    Beschreibung: Benthic habitats of the deep Mediterranean Sea and the biodiversity they host are increasingly jeopardized by increasing human pressures, both direct and indirect, which encompass fisheries, chemical and acoustic pollution, littering, oil and gas exploration and production and marine infrastructures (i.e., cable and pipeline laying), and bioprospecting. To this, is added the pervasive and growing effects of human-induced perturbations of the climate system. International frameworks provide foundations for the protection of deep-sea ecosystems, but the lack of standardized criteria for the identification of areas deserving protection, insufficient legislative instruments and poor implementation hinder an efficient set up in practical terms. Here, we discuss the international legal frameworks and management measures in relation to the status of habitats and key species in the deep Mediterranean Basin. By comparing the results of a multi-criteria decision analysis (MCDA) and of expert evaluation (EE), we identify priority deep-sea areas for conservation and select five criteria for the designation of future protected areas in the deep Mediterranean Sea. Our results indicate that areas (1) with high ecological relevance (e.g., hosting endemic and locally endangered species and rare habitats),(2) ensuring shelf-slope connectivity (e.g., submarine canyons), and (3) subject to current and foreseeable intense anthropogenic impacts, should be prioritized for conservation. The results presented here provide an ecosystem-based conservation strategy for designating priority areas for protection in the deep Mediterranean Sea.
    Beschreibung: This study was supported by the DG ENV project IDEM (Implementation of the MSFD to the Deep Mediterranean Sea; contract EU No. 11.0661/2017/750680/SUB/EN V.C2). MC and QG-B acknowledge support from Generalitat de Catalunya autonomous government through its funding scheme to excellence research groups (Grant 2017 SGR 315).
    Schlagwort(e): biodiversity hotspots ; deep-sea ecosystems ; multicriteria decision analysis ; expert evaluation ; marine protected areas ; Marine Strategy Framework Directive ; Mediterranean Sea ; protection guidelines
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2023-09-13
    Beschreibung: Satellite images show solid marine stratocumulus cloud decks (Sc) that break up over the remote oceans. The Sc breakup is initiated by precipitation and is accompanied by a strong reduction in the cloud radiative effect. Aerosol has been shown to delay the Sc breakup by postponing the onset of precipitation, however its climatic effect is uncertain. Here we introduce a new approach that allows us to re‐cast currently observed cloud cover and albedo to their counterfactual cleaner world, enabling the first estimate of the radiative effect due to delayed cloud breakup. Using simple radiative approximation, the radiative forcing with respect to pre‐industrial times due to delayed Sc breakup is −0.39 W m−2. The radiative effect changes nearly linearly with aerosol due to the droplet concentration control on the cloud cover, suggesting a potentially accelerated warming if the current trend of reduction in aerosol emissions continues.
    Beschreibung: Plain Language Summary: The response of cloud cover to aerosol is a climatologically important quantity that has been extremely difficult to estimate. The challenge is that one would need to estimate the fractional area that is currently overcast, but which would have been partly overcast in a cleaner atmosphere. Global climate models (GCMs) are one tool to address such a problem. They allow one to change aerosol levels and to evaluate the cloud response. However, representation of warm, low‐level cloud processes, and in particular aerosol‐cloud interactions in GCMs, is inadequate. Here we introduce an observational method that allows us to re‐cast the currently observed cloud cover and albedo of oceanic warm clouds to their counterfactual state in a cleaner world. We find a linear relationship between the cloud radiative effect and droplet concentration. If we continue to experience a decrease in aerosol emissions then we anticipate a reduction in the aerosol‐cloud radiative effect. The global annual radiative forcing associated with anthropogenic aerosol delaying closed cell breakup is found to be −0.39 W m−2.
    Beschreibung: Key Points: A simple model is presented to describe closed cell breakup by initiation of precipitation. The model demonstrates that the global annual radiative effect due to delayed closed cells breakup changes nearly linearly with emissions. The linearity emerges from the nearly linear relationship between cloud cover and albedo.
    Beschreibung: German Research Foundation
    Beschreibung: Department of Energy's Atmospheric System Research
    Beschreibung: Royal Society University Research Fellowship
    Beschreibung: https://ladsweb.modaps.eosdis.nasa.gov/archive/allData/61/MOD06_L2/
    Beschreibung: https://ceres-tool.larc.nasa.gov/ord-tool/jsp/SSF1degEd41Selection.jsp
    Beschreibung: https://doi.org/10.24381/cds.bd0915c6
    Beschreibung: https://doi.org/10.5281/zenodo.7072605
    Schlagwort(e): ddc:551.5 ; cloud radiative effect ; stratocumulus ; aerosol cloud interactions ; transitions ; closed cells ; open cells
    Sprache: Englisch
    Materialart: doc-type:article
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    facet.materialart.
    Unbekannt
    In:  Zoologische Mededelingen vol. 56 no. 11, pp. 139-142
    Publikationsdatum: 2024-01-12
    Beschreibung: A new goboid species, Quisquilius flavicaudatus, was found in the Red sea. D VI, I 8; A I 8; \xce\xa1 16-17; LL 23-25; TR 6-7; PreD 6; GR 3 + 1 + 10; V I 5 partly fused by a delicate membrane. The caudal peduncle and caudal fins are yellow. Red spots are found on the head and on the front of the body.\nThe new species is distinguished from the other Quisquilius species in the Western Indian Ocean and the Red Sea by having the lowest count of soft dorsal rays and scales in LL and PreD.
    Repository-Name: National Museum of Natural History, Netherlands
    Materialart: info:eu-repo/semantics/article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    In:  Zoologische Mededelingen vol. 55 no. 20, pp. 231-234
    Publikationsdatum: 2024-01-12
    Beschreibung: INTRODUCTION\nThe genus Fowleria Jordan & Evermann, 1903 is represented in the Red Sea by four species: F. aurita (Valenciennes, 1831) (the type species); F. variegata (Cuvier & Valenciennes, 1832); F. isostigma (Jordan & Seale, 1905) and F. marmorata (Alleyn & Mecleay, 1876). All of them are very similar to each other in their meristic counts and body proportions, but differ from each other in specific colour patterns.\nIn the course of research of animals living within branched corals in the Red Sea, a new species of Fowleria was found.\nThe new species, F. abocellata, was compared with the other congeneric species (Red Sea material) and found to have a unique colour pattern which enabled this species to be easily distinguished from all the rest. Until now this species was collected from the corals Acropora humilis Dana and Acropora scandens (Klunzinger) at a depth of 3-10 meters. Several specimens of the new species were kept for several months in aquaria with other small fishes and provided with flowerpots and two Acropora scandens corals. The cardinal fish remained constantly among the coral branches, coming out only during feeding times, when they broke out for a second or two towards the prey (Artemia salinae (Linnaeus) and very small fishes).\nAbbreviations used: HUJ = Fish collection of Hebrew University Jerusalem; TAU = Fish collection of Tel Aviv University; RMNH = Fish collection of the Rijksmuseum van Natuurlijke Historie, Leiden; SL = Standard length (in mm); TL = Total length (in mm).\n\nMATERIAL EXAMINED\nFowleria abocellata n. sp. \xe2\x80\x94 Holotype : TAU 7377, Elat (Gulf of Elat - Sinai penin-
    Repository-Name: National Museum of Natural History, Netherlands
    Materialart: info:eu-repo/semantics/article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2011-11-23
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2016-03-04
    Beschreibung: Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Standort Signatur Erwartet Verfügbarkeit
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