ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Cambridge University Press
  • Annual Reviews
  • 2020-2022  (4,319)
  • 2005-2009  (10,898)
  • 1990-1994  (17,774)
  • 1980-1984  (13,729)
Collection
Years
Year
  • 1
    Unknown
    Cambridge, U.K ; New York, N.Y : Cambridge University Press
    Keywords: Cellular telephone services industry ; Electronic books ; Mobile communication systems, Economic aspects ; Wireless communication systems, Economic aspects
    Pages: 1 v. (various pagings)
    ISBN: 0-511-11564-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Unknown
    Cambridge ; New York : Cambridge University Press
    Keywords: Shakespeare, William, Tragedies ; Electronic books ; Identity (Psychology) in literature ; Tragedy ; Violence in literature
    Pages: ix, 228 p.
    ISBN: 0-511-11352-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Unknown
    New York : Cambridge University Press
    Keywords: Capital market ; Electronic books ; Futures market ; Stock exchanges
    Pages: 1 v. (various pagings)
    ISBN: 0-511-11580-6
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Keywords: Developing countries, Economic policy. ; Federal government, Developing countries.
    Pages: xi, 276 p.
    ISBN: 0-511-11566-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Unknown
    Cambridge ; New York : Cambridge University Press
    Keywords: Dynamics. ; Kinematics.
    Pages: x, 374 p.
    Edition: 3rd ed
    ISBN: 0-511-11583-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Unknown
    Cambridge ; New York : Cambridge University Press
    Keywords: Shakespeare, William, Language ; Shakespeare, William, Romeo and Juliet ; Shakespeare, William, Stage history, 1950- ; Shakespeare, William, Stage history, England, London ; Electronic books ; English language, Pronunciation, Early modern, 1500-1700 ; Globe Theatre (London, England : 1996- )
    Pages: xviii, 188 p.
    ISBN: 0-511-11364-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Unknown
    Cambridge, U.K ; New York : Cambridge University Press
    Keywords: Electronic books ; Religion, Study and teaching (Higher) ; Theology, Study and teaching (Higher)
    Pages: xvii, 230 p.
    ISBN: 0-511-11355-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Unknown
    Cambridge [England] ; New York : Cambridge University Press
    Keywords: Engineering mathematics, Data processing. ; Numerical analysis, Data processing. ; MATLAB.
    Pages: viii, 426 p.
    ISBN: 0-511-12811-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Unknown
    New York : Cambridge University Press
    Keywords: Materials, Mechanical properties.
    Pages: xx, 425 p.
    ISBN: 0-511-11575-X
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Unknown
    Cambridge, UK ; New York : Cambridge University Press
    Keywords: Autonomy (Psychology) ; Electronic books ; Ethics, Modern
    Notes: Planning agency, autonomous agency / Michael E. Bratman -- Autonomy without free will / Bernard Berofsky -- Autonomy and the paradox of self-creation : infinite regresses, finite selves, and the limits of authenticity / Robert Noggle -- Agnostic autonomism revisited / Alfred R. Mele -- Feminist intuitions and the normative substance of autonomy / Paul Benson -- Autonomy and personal integration / Laura Waddell Ekstrom -- Responsibility, applied ethics, and complex autonomy theories / Nomy Arpaly -- Autonomy and free agency / Marina A.L. Oshana -- The relationship between autonomous and morally responsible agency / Michael McKenna -- Alternative possibilities, personal autonomy, and moral responsibility / Ishtiyaque Haji -- Freedom within reason / Susan Wolf -- Procedural autonomy and liberal legitimacy / John Christman -- The concept of autonomy in bioethics : an unwarranted fall from grace / Thomas May -- Who deserves autonomy, and whose autonomy deserves respect? / Tom L. Beauchamp -- Autonomy, diminished life, and the threshold for use / R.G. Frey
    Pages: ix, 350 p.
    ISBN: 0-511-08224-X
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Unknown
    Cambridge, UK ; New York : Cambridge University Press
    Keywords: Kant, Immanuel,, 1724-1804. ; Causation.
    Pages: xi, 451 p.
    ISBN: 0-511-08217-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Unknown
    Cambridge, UK ; New York : Cambridge University Press
    Keywords: Monte Carlo method. ; Statistical physics.
    Pages: xv, 432 p.
    Edition: 2nd ed
    ISBN: 0-511-13098-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Unknown
    Cambridge ; New York : Cambridge University Press
    Keywords: Equality. ; Minorities. ; Minorities, Civil rights. ; Multiculturalism. ; Social conflict. ; Social groups.
    Pages: xii, 390 p.
    ISBN: 0-511-08065-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Unknown
    Cambridge, UK ; New York : Cambridge University Press
    Keywords: Frege, Gottlob,, 1848-1925.
    Notes: Biography -- Function and argument -- Sense and reference -- Frege's Begriffsschrift theory of identity -- Concept and object -- Names and descriptions -- Existence -- Thought, truth value and assertion -- Indirect reference -- Through the quotation marks
    Pages: xix, 226 p.
    ISBN: 0-511-10977-6
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Unknown
    Cambridge : Cambridge University Press
    Keywords: Space time codes.
    Pages: 1 v. (various pagings)
    ISBN: 0-511-11562-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2020-08-24
    Description: The effect of freshwater sources on wintertime sea-ice CO2 processes was studied from the glacier front to the outer Tempelfjorden, Svalbard, in sea ice, glacier ice, brine and snow. March–April 2012 was mild, and the fjord was mainly covered with drift ice, in contrast to the observed thicker fast ice in the colder April 2013. This resulted in different physical and chemical properties of the sea ice and under-ice water. Data from stable oxygen isotopic ratios and salinity showed that the sea ice at the glacier front in April 2012 contained on average 54% of frozen-in glacial meltwater. This was five times higher than in April 2013, where the ice was frozen seawater. In April 2012, the largest excess of sea-ice total alkalinity (AT), carbonate ion ([CO32−]) and bicarbonate ion concentrations ([HCO3−]) relative to salinity was mainly related to dissolved dolomite and calcite incorporated during freezing of mineral-enriched glacial water. In April 2013, the excess of these variables was mainly due to ikaite dissolution as a result of sea-ice processes. Dolomite dissolution increased sea-ice AT twice as much as ikaite and calcite dissolution, implying different buffering capacity and potential for ocean CO2 uptake in a changing climate.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2020-09-24
    Description: Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  EPIC3Life in extreme environments - Insights in biological capability, Ecological Reviews, Cambridge, Cambridge University Press, 16 p., pp. 218-233, ISBN: 978-1-108-72420-3
    Publication Date: 2020-10-05
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  EPIC3Environmental Conservation, Cambridge University Press, pp. 1-6, ISSN: 0376-8929
    Publication Date: 2021-01-20
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  EPIC3Journal of Glaciology, Cambridge University Press, 67(261), pp. 84-90
    Publication Date: 2021-01-25
    Description: The validity of any glaciological paleo proxy used to interpret climate records is based on the level of understanding of their transfer from the atmosphere into the ice sheet and their recording in the snowpack. Large spatial noise in snow properties is observed, as the wind constantly redistributes the deposited snow at the surface routed by the local topography. To increase the signal-tonoise ratio and getting a representative estimate of snow properties with respect to the high spatial variability, a large number of snow profiles is needed. However, the classical way of obtaining profiles via snow-pits is time and energy-consuming, and thus unfavourable for large surface sampling programs. In response, we present a dual-tube technique to sample the upper metre of the snowpack at a variable depth resolution with high efficiency. The developed device is robust and avoids contact with the samples by exhibiting two tubes attached alongside each other in order to (1) contain the snow core sample and (2) to access the bottom of the sample, respectively. We demonstrate the performance of the technique through two case studies in East Antarctica where we analysed the variability of water isotopes at a 100 m and 5 km spatial scales.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  EPIC3Radiocarbon, Cambridge University Press, 62(4), pp. 865-871, ISSN: 0033-8222
    Publication Date: 2020-09-24
    Description: Beyond ~13.9 cal kBP, the IntCal20 radiocarbon (14C) calibration curve is based upon combining data across a range of different archives including corals and planktic foraminifera. In order to reliably incorporate such marine data into an atmospheric curve, we need to resolve these records into their constituent atmospheric signal and marine reservoir age. We present results of marine reservoir age simulations enabling this resolution, applying the LSG ocean general circulation model forced with various climatic background conditions and with atmospheric radiocarbon changes according to the Hulu Cave speleothem record. Simulating the spatiotemporal evolution of reservoir ages between 54,000 and 10,700 cal BP, we find reservoir ages between 500 and 1400 yr in the low- and mid-latitudes, but also more than 3000 yr in the polar seas. Our results are broadly in agreement with available marine radiocarbon reconstructions, with the caveat that continental margins, marginal seas, or tropical lagoons are not properly resolved in our coarse-resolution model.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2020-09-24
    Description: The concentration of radiocarbon (14C) differs between ocean and atmosphere. Radiocarbon determinations from samples which obtained their 14C in the marine environment therefore need a marine-specific calibration curve and cannot be calibrated directly against the atmospheric-based IntCal20 curve. This paper presents Marine20, an update to the internationally agreed marine radiocarbon age calibration curve that provides a non-polar global-average marine record of radiocarbon from 0–55 cal kBP and serves as a baseline for regional oceanic variation. Marine20 is intended for calibration of marine radiocarbon samples from non-polar regions; it is not suitable for calibration in polar regions where variability in sea ice extent, ocean upwelling and air-sea gas exchange may have caused larger changes to concentrations of marine radiocarbon. The Marine20 curve is based upon 500 simulations with an ocean/atmosphere/biosphere box-model of the global carbon cycle that has been forced by posterior realizations of our Northern Hemispheric atmospheric IntCal20 14C curve and reconstructed changes in CO2 obtained from ice core data. These forcings enable us to incorporate carbon cycle dynamics and temporal changes in the atmospheric 14C level. The box-model simulations of the global-average marine radiocarbon reservoir age are similar to those of a more complex three-dimensional ocean general circulation model. However, simplicity and speed of the box model allow us to use a Monte Carlo approach to rigorously propagate the uncertainty in both the historic concentration of atmospheric 14C and other key parameters of the carbon cycle through to our final Marine20 calibration curve. This robust propagation of uncertainty is fundamental to providing reliable precision for the radiocarbon age calibration of marine based samples. We make a first step towards deconvolving the contributions of different processes to the total uncertainty; discuss the main differences of Marine20 from the previous age calibration curve Marine13; and identify the limitations of our approach together with key areas for further work. The updated values for ΔR, the regional marine radiocarbon reservoir age corrections required to calibrate against Marine20, can be found at the data base http://calib.org/marine/.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  EPIC3Polar Record, Cambridge University Press, 57(e12), pp. 1-6, ISSN: 0032-2474
    Publication Date: 2021-04-15
    Description: The distribution, density and percentage contribution of pack ice seals during ship-board censuses in the marginal sea ice zone beyond the Lazarev Sea in spring 2019 are presented. Adult/juvenile crabeater seals (n = 19), leopard seals (n = 3) and Ross seals (n = 10) were sighted during 582.2 nm of censuses along the ship’s track line in the area bounded by 00°00’–22°E and 56°–60°S. Antarctic fur seals (n = 21) were only encountered on the outer fringes of the pack ice, and Weddell seals were absent due to their primary use of fast ice and inner pack ice habitats close to the coast. Crabeater seal sightings included juveniles (n = 2) and another four groups of 2–3 unclassified crabeater seals, singletons (n = 5), single mothers with pups (n = 3) and a family group (n = 1 triad). Only one leopard seal attended a pup, while no Ross seal pups were located. The survey was likely of insufficient effort, in both extent (north of 60°S) and duration (18 days), to locate seals in considerable numbers this early (late October/early November) in their austral spring breeding season.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2017-04-04
    Description: Twenty eruptive events from the Northeast Crater of Stromboli volcano recorded by a thermal monitoring camera in early 2004 were analysed in order to understand the eruptive dynamics. Selected eventswere chosen to be typical of explosions that characterize the steady activity of Stromboli in terms of jet height and duration. Most of the explosions consisted of clast-rich single bursts, originating from the same vent inside the Northeast Crater. Conspicuous ash emission was scarce. Eruptions were preceded by the flashing of a perturbation wave characterized by low temperatures and an average propagation velocity of about 35–100 m s−1. This perturbation was thought to be caused by the bursting of the gas slug at the bottom of the crater and is interpreted as an air wave. This was immediately followed by the expansion of a jet of ‘hot’ gas and particles, at a velocity of 35–75 m s−1. Ejecta coarser than 138 cm appeared ∼1.6–2 s after the onset of the explosion, moving at a variable velocity (30–60 m s−1). Eruptive events were either vertical or inclined 7–13◦ towards the NNW. This inclination is thought to be a consequence either of the morphology of the conduit, following modest rock falls that partially obstructed the uppermost part of the crater, or of the displacement of the internal conduit due to the explosive activity of the volcano. The instability of the summit area is a further possible cause of the deformation of the conduit.
    Description: This work was partially funded by the Istituto Nazionale di Geofisica e Vulcanologia and the Dipartimento della Protezione Civile, Italy, project INGVDPC V2
    Description: Published
    Description: 591–601
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 1.10. TTC - Telerilevamento
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: explosive dynamic ; thermal video monitoring ; volcano-tectonic structures ; volcano collapses ; Stromboli ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Publication Date: 2020-05-27
    Description: Volcanism and metamorphism are the principal geologic processes that drive carbon transfer from the interior of Earth to the surface reservoir.1–4 Input of carbon to the surface reservoir through volcanic degassing is balanced by removal through silicate weathering and the subduction of carbon-bearing marine deposits over million-year timescales. The magnitude of the volcanic carbon flux is thus of fundamental importance for stabilization of atmospheric CO2 and for long-term climate. It is likely that the “deep” carbon reservoir far exceeds the size of the surface reservoir in terms of mass;5,6 more than 99%of Earth’s carbon may reside in the core, mantle, and crust. The relatively high flux of volcanic carbon to the surface reservoir, combined with the reservoir’s small size, results in a short residence time for carbon in the ocean–atmosphere–biosphere system (~200 ka).7 The implication is that changes in the flux of volcanic carbon can affect the climate and ultimately the habitability of the planet on geologic timescales. In order to understand this delicate balance, we must first quantify the current volcanic flux of carbon to the atmosphere and understand the factors that control this flux.
    Description: Published
    Description: 188-236
    Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2000. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 403 (2000): 37-65, doi:10.1017/S0022112099006916.
    Description: The dynamics of expanding domes of isothermal lava are studied by treating the lava as a viscoplastic material with the Herschel–Bulkley constitutive law. Thin-layer theory is developed for radially symmetric extrusions onto horizontal plates. This provides an evolution equation for the thickness of the fluid that can be used to model expanding isothermal lava domes. Numerical and analytical solutions are derived that explore the effects of yield stress, shear thinning and basal sliding on the dome evolution. The results are briefly compared with an experimental study. It is found that it is difficult to unravel the combined effects of shear thinning and yield stress; this may prove important to studies that attempt to infer yield stress from morphology of flowing lava.
    Description: The financial support of an EPSRC Advanced Fellowship is gratefully acknowledged by R.V. C. N. J. B. was partially supported by the NSF Grant OCE-9616017 and an EPSRC Visiting Fellowship Grant GR/M50409.
    Keywords: Isothermal lava domes
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 1102860 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Parasitology 128 (2004): 577-584, doi:10.1017/S0031182004005025.
    Description: Human serum high-density lipoprotein (HDL) is necessary and sufficient for the short-term maintenance of Plasmodium falciparum in in vitro culture. However, at high concentrations it is toxic to the parasite. A heat-labile component is apparently responsible for the stage-specific toxicity to parasites within infected erythrocytes 12–42 h after invasion, i.e. during trophozoite maturation. The effects of HDL on parasite metabolism (as determined by nucleic acid synthesis) are evident at about 30 h after invasion. Parasites treated with HDL show gross abnormalities by light and electron microscopy.
    Description: Professor Hajduk was supported by NIH. Professor Day was supported by a Research Leave Fellowship from The Wellcome Trust. Dr Imrie and Ms Carter were supported by Programme Grant funding awarded to Professor Day from The Wellcome Trust. Dr Ferguson was supported by an equipment grant from The Wellcome Trust.
    Keywords: Plasmodium falciparum ; High density lipoprotein
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 179037 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Geological Magazine 141 (2004): 195-207, doi:10.1017/S001675680400891X.
    Description: Because magmatism associated with subduction is thought to be the principal source for continental crust generation, assessing the relative contribution of pre-existing (subducted and assimilated) continental material to arc magmatism in accreted arcs is important to understanding the origin of continental crust. We present a detailed Nd isotopic stratigraphy for volcanic and volcaniclastic formations from the South Mayo Trough, an accreted oceanic arc exposed in the western Irish Caledonides. These units span an arc–continent collision event, the Grampian (Taconic) Orogeny, in which an intra-oceanic island arc was accreted onto the passive continental margin of Laurentia starting at [similar] 475 Ma (Arenig). The stratigraphy corresponding to pre-, syn- and post-collisional volcanism reveals a progression of [varepsilon]Nd(t) from strongly positive values, consistent with melt derivation almost exclusively from oceanic mantle beneath the arc, to strongly negative values, indicating incorporation of continental material into the melt. Using [varepsilon]Nd(t) values of meta-sediments that represent the Laurentian passive margin and accretionary prism, we are able to quantify the relative proportions of continent-derived melt at various stages of arc formation and accretion. Mass balance calculations show that mantle-derived magmatism contributes substantially to melt production during all stages of arc–continent collision, never accounting for less than 21% of the total. This implies that a significant addition of new, rather than recycled, continental crust can accompany arc–continent collision and continental arc magmatism.
    Keywords: Grampian Orogeny ; Western Ireland ; Continental crust ; Nd isotopes ; Laurentia ; Iapetus Ocean
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 509750 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2007. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 574 (2007): 465-493, doi:10.1017/S0022112006004216.
    Description: Acoustic Doppler velocity profiler (ADVP) measurements of instantaneous three-dimensional velocity profiles over the entire turbulent boundary layer height, δ, of rough-bed open-channel flows at moderate Reynolds numbers show the presence of large scale coherent shear stress structures (called LC3S herein) in the zones of uniformly retarded streamwise momentum. LC3S events over streamwise distances of several boundary layer thicknesses dominate the mean shear dynamics. Polymodal histograms of short streamwise velocity samples confirm the subdivision of uniform streamwise momentum into three zones also observed by Adrian et al. (J. Fluid Mech., vol. 422, 2000, p. 1). The mean streamwise dimension of the zones varies between 1δ and 2.5δ. In the intermediate region (0.2〈z/δ〈0.75), the contribution of conditionally sampled u'w' events to the mean vertical turbulent kinetic energy (TKE) flux as a function of threshold level H is found to be generated by LC3S events above a critical threshold level Hmax for which the ascendant net momentum flux between LC3S of ejection and sweep types is maximal. The vertical profile of Hmax is nearly constant over the intermediate region, with a value of 5 independent of the flow conditions. Very good agreement is found for all flow conditions including the free-stream shear flows studied in Adrian et al. (2000). If normalized by the squared bed friction velocity, the ascendant net momentum flux containing 90% of the mean TKE flux is equal to 20% of the shear stress due to bed friction. In the intermediate region this value is nearly constant for all flow conditions investigated herein. It can be deduced that free-surface turbulence in open-channel flows originates from processes driven by LC3S, associated with the zonal organization of streamwise momentum. The good agreement with mean quadrant distribution results in the literature implies that LC3S identified in this study are common features in the outer region of shear flows.
    Description: The study was supported by the Swiss National Foundation for Scientific Research for the experimental part (grant 2100 050739) and the French National Center for Scientific Research (CNRS) for the data analysis and interpretation.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2005. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 540 (2005): 49-73, doi:10.1017/S002211200500577X.
    Description: Circulation driven by horizontal differential heating is studied, using a double-walled Plexiglas tank (20×15×2.5 cm3) filled with salt water. For instances of heating/cooling from above and below, results indicate that there is always quasi-equilibrium circulation. In contrast to most previous results from experimental/ numerical studies, circulation in our experiments appears in the form of a shallow cell adjacent to the boundary of thermal forcing. The non-dimensional stream-function maximum confirms the 1/5-power law of Rossby, Ψ ∼Ra1/5 L . Dissipation rate measured in the experiments appears to be consistent with theory. For cases of heating/cooling from a sloping bottom, circulation is similar to cases with a flat bottom; circulation is strong if heating is below cooling, but it is rather weak if heating is above cooling. Nevertheless, circulation in all cases is visible to the naked eye.
    Description: W. W. was supported by The National Natural Science Foundation of China through grant 40476010 and the Research Fund for the Doctoral Program of Higher Education through grant 20030423011. R. X. H. was supported by the National Science Foundation through grant OCE-0094807 and the National Aero- Space Administration through Contract 1229833 (NRA-00-OES-05) to the Woods Hole Oceanographic Institution.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    facet.materialart.
    Unknown
    Cambridge University Press
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2008. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 602 (2008): 241-266, doi:10.1017/S0022112008000827.
    Description: The stability of a hydraulically driven sill flow in a rotating channel with smoothly varying cross-section is considered. The smooth topography forces the thickness of the moving layer to vanish at its two edges. The basic flow is assumed to have zero potential vorticity, as is the case in elementary models of the hydraulic behaviour of deep ocean straits. Such flows are found to always satisfy Ripa's necessary condition for instability. Direct calculation of the linear growth rates and numerical simulation of finite-amplitude behaviour suggests that the flows are, in fact, always unstable. The growth rates and nonlinear evolution depend largely on the dimensionless channel curvature κ=2αg′/f2, where 2α is the dimensional curvature, g′ is the reduced gravity, and f is the Coriolis parameter. Very small positive (or negative) values of κ correspond to dynamically wide channels and are associated with strong instability and the breakup of the basic flow into a train of eddies. For moderate or large values of κ, the instability widens the flow and increases its potential vorticity but does not destroy its character as a coherent stream. Ripa's condition for stability suggests a theory for the final width and potential vorticity that works moderately well. The observed and predicted growth in these quantities are minimal for κ≥1, suggesting that the zero-potential-vorticity approximation holds when the channel is narrower than a Rossby radius based on the initial maximum depth. The instability results from a resonant interaction between two waves trapped on opposite edges of the stream. Interactions can occur between two Kelvin-like frontal waves, between two inertia–gravity waves, or between one wave of each type. The growing disturbance has zero energy and extracts zero energy from the mean. At the same time, there is an overall conversion of kinetic energy to potential energy for κ〉0, with the reverse occurring for κ〈0. When it acts on a hydraulically controlled basic state, the instability tends to eliminate the band of counterflow that is predicted by hydraulic theory and that confounds hydraulic-based estimates of volume fluxes in the field. Eddy generation downstream of the controlling sill occurs if the downstream value of κ is sufficiently small.
    Description: This work was supported by the National Science Foundation (Grant OCE- 0525729).
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Publication Date: 2022-05-25
    Description: Author Posting. © Annual Reviews, 2003. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Environment and Resources 28 (2003): 521-558, doi:10.1146/annurev.energy.28.011503.163443.
    Description: Agriculture and industrial development have led to inadvertent changes in the natural carbon cycle. As a consequence, concentrations of carbon dioxide and other greenhouse gases have increased in the atmosphere and may lead to changes in climate. The current challenge facing society is to develop options for future management of the carbon cycle. A variety of approaches has been suggested: direct reduction of emissions, deliberate manipulation of the natural carbon cycle to enhance sequestration, and capture and isolation of carbon from fossil fuel use. Policy development to date has laid out some of the general principles to which carbon management should adhere. These are summarized as: how much carbon is stored, by what means, and for how long. To successfully manage carbon for climate purposes requires increased understanding of carbon cycle dynamics and improvement in the scientific capabilities available for measurement as well as for policy needs. The specific needs for scientific information to underpin carbon cycle management decisions are not yet broadly known. A stronger dialogue between decision makers and scientists must be developed to foster improved application of scientific knowledge to decisions. This review focuses on the current knowledge of the carbon cycle, carbon measurement capabilities (with an emphasis on the continental scale) and the relevance of carbon cycle science to carbon sequestration goals.
    Description: The National Center for Atmospheric Research is supported by the National Science Foundation.
    Keywords: Carbon sequestration ; Measurement techniques ; Climate ; Kyoto protocol
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 406392 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 516 (2004): 83-113, doi:10.1017/S0022112004000473.
    Description: Oceanic observations indicate that abyssal mixing tends to be localized to regions of rough topography. How localized mixing interacts with the ambient fluid in a stratified, rotating system is an open question. To gain insight into this complicated process laboratory experiments are used to explore the interaction of mechanically induced boundary mixing and an interior body of linearly stratified rotating fluid. Turbulence is generated by a single vertically oscillating horizontal bar of finite horizontal extent, located at mid-depth along the tank wall. The turbulence forms a region of mixed fluid which quickly reaches a steady-state height and collapses into the interior. The mixed-layer thickness, $h_m\,{\sim}\,\gamma ({\omega}/{N})^{1/2}$, is spatially uniform and independent of the Coriolis frequency $f$. $N$ is the initial buoyancy frequency, $\omega$ is the bar oscillation frequency, and $\gamma\,{\approx}\,1$ cm is an empirical constant determined by the bar geometry. Surprisingly, the export of mixed fluid does not occur as a boundary current along the tank perimeter. Rather, mixed fluid intrudes directly into the interior as a radial front of uniform height, advancing with a speed comparable to a gravity current. The volume of mixed fluid grows linearly with time, $V\,{\propto}\,({N}/{f})^{3/2}h_m^3 \textit{ft}$, and is independent of the lateral extent of the mixing bar. Entrainment into the turbulent zone occurs principally through horizontal flows at the level of the mixing that appear to eliminate export by a geostrophic boundary flow. The circulation patterns suggest a model of unmixed fluid laterally entrained at velocity $u_e \,{\sim}\,Nh_m $ into the open sides of a turbulent zone with height $h_{m}$ and a length, perpendicular to the boundary, proportional to $L_f \,{\equiv}\,\gamma ({\omega}/{f})^{1/2}$. Here $L_{f}$ is an equilibrium length scale associated with rotational control of bar-generated turbulence. The model flux of exported mixed fluid $Q\,{\sim}\,h_m L_f u_e$ is constant and in agreement with the experiments.
    Description: This work was supported by the Ocean Ventures Fund, the Westcott Fund and the WHOI Academic Programs Office. Financial support was also provided by the National Science Foundation through grant OCE-9616949.
    Keywords: Abyssal mixing ; Stratified rotating system
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 519410 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 506 (2004): 217-244, doi:10.1017/S0022112004008572.
    Description: The effect of both vertical and horizontal components of the Earth's rotation on plumes during deep convection in the ocean is studied. In the laboratory, the misalignment, characterized by the angle $\alpha$, between the buoyancy force (‘effective’ free-fall acceleration ${\bm g}_e$) and the rotation axis ${\bm \Omega}$ is produced by using the centrifugal force: an experimental tank was placed at a large distance from the centre of the turntable. The mathematical analogy between the laboratory model and the oceanic environment is presented. For $\alpha\,{=}\,30^\circ$, a number of laboratory experiments spanning a wide range of the buoyancy flux parameter, and correspondingly Reynolds number, is used to illustrate the development of the convective plume from a point source in regimes ranging from weakly to highly turbulent. New features of the flow, as compared to $\alpha\,{=}\,0$, are documented and explained. The incoming heavier dyed fluid jet disintegrates into fast-sinking coherent blobs (in a low-Reynolds-number regime) or turbulent billows (in a high-Reynolds-number regime) and a more diffuse cloud of highly diluted dyed water. An analysis of the forces acting on an ellipsoid moving in a rotating fluid with the main balance including the buoyancy, Coriolis forces, and the hydrodynamic reaction due to generation of inertial waves correctly predicts the trajectory of a descending blob. It also explains the tendency of the plume to develop in the direction intermediate between ${\bm g}_e$ and ${\bm \Omega}$ and to shift ‘eastward’ (lagging the rotation of the centrifuge) if the plume is envisaged as an ensemble of blobs. The stretching of the highly diluted dyed water along the absolute vorticity tubes with simultaneous shearing by horizontal quasi-two-dimensional flow produces conspicuous tilted structures or tilted Taylor ‘ink walls’. The misalignment between ${\bm g}_e$ and ${\bm \Omega}$ enhances the turbulent mixing and development of tilted structures by breaking the symmetry and producing motions directed away from the rotation axis. We argue that the conditions at the sites of ocean deep convection are favourable for the development of tilted structures because of the smallness of the Rossby number and an extreme homogenization of the mixed layer. We hypothesize that the homogenized sublayers observed within actively convecting regions in the ocean may not be horizontal, but in fact analogous to the tilted ‘ink walls’ observed in the laboratory experiments and that they represent the internal structure of a plume on horizontal scales smaller than its depth.
    Description: This work was supported by a grant from The Andrew W. Mellon Foundation Endowed Fund for Innovative Research and by the National Science Foundation grant OCE-0116910.
    Keywords: Convective plumes
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 449374 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2000. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 404 (2000):117-149, doi:10.1017/S0022112099007065.
    Description: In order to gain insight into the hydraulics of rotating-channel flow, a set of initial-value problems analogous to Long's towing experiments is considered. Specifically, we calculate the adjustment caused by the introduction of a stationary obstacle into a steady, single-layer flow in a rotating channel of infinite length. Using the semigeostrophic approximation and the assumption of uniform potential vorticity, we predict the critical obstacle height above which upstream influence occurs. This height is a function of the initial Froude number, the ratio of the channel width to an appropriately defined Rossby radius of deformation, and a third parameter governing how the initial volume flux in sidewall boundary layers is partitioned. (In all cases, the latter is held to a fixed value specifying zero flow in the right-hand (facing downstream) boundary layer.) The temporal development of the flow according to the full, two-dimensional shallow water equations is calculated numerically, revealing numerous interesting features such as upstream-propagating shocks and separated rarefying intrusions, downstream hydraulic jumps in both depth and stream width, flow separation, and two types of recirculations. The semigeostrophic prediction of the critical obstacle height proves accurate for relatively narrow channels and moderately accurate for wide channels. Significantly, we find that contact with the left-hand wall (facing downstream) is crucial to most of the interesting and important features. For example, no instances are found of hydraulic control of flow that is separated from the left-hand wall at the sill, despite the fact that such states have been predicted by previous semigeostrophic theories. The calculations result in a series of regime diagrams that should be very helpful for investigators who wish to gain insight into rotating, hydraulically driven flow.
    Description: The authors have been supported by the National Science Foundation through Grants (OCE-9810599 for L.J.P. and K.R.H. and OCE-9711186 for EPC). L.J.P. also received support from the Office of Naval Research under Grant N00014-95-1-0456 and K.R.H. under grant N00014-93-1-0263.
    Keywords: Rotating-channel flow ; Hydraulically driven flow
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 3069192 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 514 (2004): 107-119, doi:10.1017/S0022112004000126.
    Description: While acoustic scatter from oceanic turbulence is sensitive to temperature–salinity covariations, there are unfortunately no published measurements of the turbulent temperature–salinity co-spectrum. Several models have been proposed for the form of the co-spectrum of two scalars in turbulence, but they all produce unsatisfactory results when applied to the turbulent scattering equations (either predicting negative scattering cross-sections in some regimes or predicting implausible levels of correlation between temperature and salinity at some scales). A new model is proposed and shown to give physically plausible scattering predictions in all density regimes. High-frequency acoustic data illustrate the importance of the co-spectrum for acoustic scattering, but were collected in a density regime where there is little difference between the co-spectrum models.
    Description: This work was supported by NSERC and by ONR under grant #N00014-93-1-0362.
    Keywords: Oceanic turbulence ; Co-spectrum ; Temperature–salinity covariations
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 474199 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2002. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 452 (2002): 97-121, doi:10.1017/S0022112001006668.
    Description: Buoyancy-driven surface currents were generated in the laboratory by releasing buoyant fluid from a source adjacent to a vertical boundary in a rotating container. Different bottom topographies that simulate both a continental slope and a continental ridge were introduced in the container. The topography modified the flow in comparison with the at bottom case where the current grew in width and depth until it became unstable once to non-axisymmetric disturbances. However, when topography was introduced a second instability of the buoyancy-driven current was observed. The most important parameter describing the flow is the ratio of continental shelf width W to the width L* of the current at the onset of the instability. The values of L* for the first instability, and L*[minus sign]W for the second instability were not influenced by the topography and were 2–6 times the Rossby radius. Thus, the parameter describing the flow can be expressed as the ratio of the width of the continental shelf to the Rossby radius. When this ratio is larger than 2–6 the second instability was observed on the current front. A continental ridge allowed the disturbance to grow to larger amplitude with formation of eddies and fronts, while a gentle continental slope reduced the growth rate and amplitude of the most unstable mode, when compared to the continental ridge topography. When present, eddies did not separate from the main current, and remained near the shelf break. On the other hand, for the largest values of the Rossby radius the first instability was suppressed and the flow was observed to remain stable. A small but significant variation was found in the wavelength of the first instability, which was smaller for a current over topography than over a flat bottom.
    Description: Partial support for C.C. was provided by a TMR fellowship, MAS3-CT96-5017.
    Keywords: Buoyancy-driven currents ; Bottom topography
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 750211 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    facet.materialart.
    Unknown
    Annual Reviews
    Publication Date: 2022-05-25
    Description: Author Posting. © Annual Reviews, 2006. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Fluid Mechanics 38 (2006): 395-425, doi:10.1146/annurev.fluid.38.050304.092129.
    Description: Over the past four decades, the combination of in situ and remote sensing observations has demonstrated that long nonlinear internal solitary-like waves are ubiquitous features of coastal oceans. The following provides an overview of the properties of steady internal solitary waves and the transient processes of wave generation and evolution, primarily from the point of view of weakly nonlinear theory, of which the Korteweg-de Vries equation is the most frequently used example. However, the oceanographically important processes of wave instability and breaking, generally inaccessible with these models, are also discussed. Furthermore, observations often show strongly nonlinear waves whose properties can only be explained with fully nonlinear models.
    Description: KRH acknowledges support from NSF and ONR and an Independent Study Award from the Woods Hole Oceanographic Institution. WKM acknowledges support from NSF and ONR, which has made his work in this area possible, in close collaboration with former graduate students at Scripps Institution of Oceanography and MIT.
    Keywords: Solitary waves ; Nonlinear waves ; Stratified flow ; Physical Oceanography
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 1034976 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    facet.materialart.
    Unknown
    Cambridge University Press
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2000. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published Journal of the Marine Biological Association of the UK 80 (2000): 827-834, doi:10.1017/S0025315400002800.
    Description: The shell and internal anatomy of the montacutid bivalve Mysella verrilli is described for the first time. The species is remarkable in that the oesophagus has developed into a suctorial proboscis. This has been accompanied by the loss of the palps. In addition the gonads have been extended from the dorsal part of the body to form two gill-like extensions to which the reduced inner demibranchs attach along the postero–ventral margin. Mysella verrilli broods its young in the mantle cavity to the late veliger stage before releasing them. It is believed that the species is probably a suctorial ectoparasite on a soft-bodied benthic invertebrate.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2022-05-25
    Description: Author Posting. © Microscopy Society of America, 2007. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Microscopy and Microanalysis 13 Suppl. 2 (2007): 10-11, doi:10.1017/S1431927607075186.
    Description: Differential interference contrast (DIC) microscopy is widely used to observe structure and motion in unstained, transparent living cells and isolated organelles, producing a monochromatic shadowcast image of optical phase gradient. Polarized light microscopy (Pol) reveals structural anisotropy due to form birefringence, intrinsic birefringence, stress birefringence, etc. DIC and Pol complement each other as, for example, in a live dividing cell, the DIC image will clearly show the chromosomes while the Pol image will depict the distribution of the birefringent microtubules in the spindle. Both methods, however, have the same shortcomings: they require the proper orientation of a specimen in relation to the optical system in order to achieve best results.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2008. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 604 (2008): 369-388, doi:10.1017/S0022112008001237.
    Description: We discuss laboratory experiments investigating mixing in a density-driven current flowing down a sloping bottom, in a rotating homogenous fluid. A systematic study spanning a wide range of Froude, 0.8 〈 Fr 〈 10, and Reynolds, 10 〈 Re 〈 1400, numbers was conducted by varying three parameters: the bottom slope; the flow rate; and the density of the dense fluid. Different flow regimes were observed, i.e. waves (non-breaking and breaking) and turbulent regimes, while changing the above parameters. Mixing in the density-driven current has been quantified within the observed regimes, and at different locations on the slope. The dependence of mixing on the relevant non-dimensional numbers, i.e. slope, Fr and Re, is discussed. The entrainment parameter, E, was found to be dependent not only on Fr, as assumed in previous studies, but also on Re. In particular, mixing increased with increasing Fr and Re. For low Fr and Re, the magnitude of the mixing was comparable to mixing in the ocean. For large Fr and Re, mixing was comparable to that observed in previous laboratory experiments that exhibited the classic turbulent entrainment behaviour.
    Description: Support was given by the National Science Foundation project number OCE-0350891.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2008. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 605 (2008): 281-291, doi:10.1017/S002211200800150X.
    Description: A condition is derived for the hydraulic criticality of a 2-layer flow with transverse variations in both layer velocities and thicknesses. The condition can be expressed in terms of a generalized composite Froude number. The derivation can be extended in order to obtain a critical condition for an N-layer system. The results apply to inviscid flows subject to the usual hydraulic approximation of gradual variations along the channel and is restricted to flows in which the velocity remains single-signed within any given layer. For an intermediate layer with a partial segment of sluggish flow, the long-wave dynamics of the overlying and underlying layers become decoupled.
    Description: The work described herein was supported by the Office of Naval Research (N00014- 07-1-0590) and the National Science Foundation (OCE-0525729).
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2008. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 616 (2008): 327-356, doi:10.1017/S0022112008003984.
    Description: A steady theory is presented for gravity currents propagating with constant speed into a stratified fluid with a general density profile. Solution curves for front speed versus height have an energy-conserving upper bound (the conjugate state) and a lower bound marked by the onset of upstream influence. The conjugate state is the largest-amplitude nonlinear internal wave supported by the ambient stratification, and in the limit of weak stratification approaches Benjamin's energy-conserving gravity current solution. When the front speed becomes critical with respect to linear long waves generated above the current, steady solutions cannot be calculated, implying upstream influence. For non-uniform stratification, the critical long-wave speed exceeds the ambient long-wave speed, and the critical-Froude-number condition appropriate for uniform stratification must be generalized. The theoretical results demonstrate a clear connection between internal waves and gravity currents. The steady theory is also compared with non-hydrostatic numerical solutions of the full lock release initial-value problem. Some solutions resemble classic gravity currents with no upstream disturbance, but others show long internal waves propagating ahead of the gravity current. Wave generation generally occurs when the stratification and current speed are such that the steady gravity current theory fails. Thus the steady theory is consistent with the occurrence of either wave-generating or steady gravity solutions to the dam-break problem. When the available potential energy of the dam is large enough, the numerical simulations approach the energy-conserving conjugate state. Existing laboratory experiments for intrusions and gravity currents produced by full-depth lock exchange flows over a range of stratification profiles show excellent agreement with the conjugate state solutions.
    Description: K. R. H. was supported by ONR grant N000140610798
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2002. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 468 (2002): 179-204, doi:10.1017/S0022112002001520.
    Description: A similarity solution to the long-wave shallow-water equations is obtained for a density current (reduced gravity = g[prime prime or minute], Coriolis parameter = f) propagating alongshore (y = 0). The potential vorticity q = f/H1 is uniform in [minus sign][infty infinity] 〈 x [less-than-or-eq, slant] xnose(t), 0 〈 y [less-than-or-eq, slant] L(x, t), and the nose of this advancing potential vorticity front displaces fluid of greater q = f/H0, which is located at L 〈 y 〈 [infty infinity]. If L0 = L([minus sign][infty infinity], t), the nose point with L(xnose(t), t) = 0 moves with velocity Unose = [surd radical]g[prime prime or minute]H0 [phi], where [phi] is a function of H1/H0, f2L20/g[prime prime or minute]H0. The assumptions made in the similarity theory are verified by an initial value solution of the complete reduced-gravity shallow-water equations. The latter also reveal the new effect of a Kelvin shock wave colliding with a potential vorticity front, as is confirmed by a laboratory experiment. Also confirmed is the expansion wave structure of the intrusion, but the observed values of Unose are only in qualitative agreement; the difference is attributed to the presence of small-scale (non-hydrostatic) turbulence in the laboratory experiment but not in the numerical solutions.
    Description: This work is funded by National Science Foundation grants OCE-9726584 & OCE-0092504 (M. E. S.) and OCE-9810599 (K. R. H.).
    Keywords: Potential vorticity front ; Frontal intrusion ; Kelvin wave
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 615286 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2003. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 481 (2003): 329-353, doi:10.1017/S0022112003004051.
    Description: In this article we investigate time-periodic shear flows in the context of the two-dimensional vorticity equation, which may be applied to describe certain large-scale atmospheric and oceanic flows. The linear stability analyses of both discrete and continuous profiles demonstrate that parametric instability can arise even in this simple model: the oscillations can stabilize (destabilize) an otherwise unstable (stable) shear flow, as in Mathieu's equation (Stoker 1950). Nonlinear simulations of the continuous oscillatory basic state support the predictions from linear theory and, in addition, illustrate the evolution of the instability process and thereby show the structure of the vortices that emerge. The discovery of parametric instability in this model suggests that this mechanism can occur in geophysical shear flows and provides an additional means through which turbulent mixing can be generated in large-scale flows.
    Description: F.P.’s and G.F.’s research was supported by grants from NSF, OPP- 9910052 and OCE-0137023. J.P.’s research is supported in part by a grant from NSF, OCE-9901654.
    Keywords: Time-periodic shear flows ; Parametric instability
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 349820 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2004. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 515 (2004): 415-443, doi:10.1017/S0022112004000576.
    Description: The investigation involves the hydraulic behaviour of a dense layer of fluid flowing over an obstacle and subject to entrainment of mass and momentum from a dynamically inactive (but possibly moving) overlying fluid. An approach based on the use of reduced gravity, shallow-water theory with a cross-interface entrainment velocity is compared with numerical simulations based on a model with continuously varying stratification and velocity. The locations of critical flow (hydraulic control) in the continuous model are estimated by observing the direction of propagation of small-amplitude long-wave disturbances introduced into the flow field. Although some of the trends predicted by the shallow-water model are observed in the continuous model, the agreement between the interface profiles and the position of critical flow is quantitatively poor. A reformulation of the equations governing the continuous flow suggests that the reduced gravity model systematically underestimates inertia and overestimates buoyancy. These differences are quantified by shape coefficients that measure the vertical non-uniformities of the density and horizontal velocity that arise, in part, by incomplete mixing of entrained mass and momentum over the lower-layer depth. Under conditions of self-similarity (as in Wood's similarity solution) the shape coefficients are constant and the formulation determines a new criterion for and location of critical flow. This location generally lies upstream of the critical section predicted by the reduced-gravity model. Self-similarity is not observed in the numerically generated flow, but the observed critical section continues to lie upstream of the location predicted by the reduced gravity model. The factors influencing this result are explored.
    Description: M. H. N. would like to thank the Danish Natural Science Research Council for financial support. L. P. and K. H. were supported by the Office of Naval Research under grant N00014-1-01-0167 and by the National Science Foundation under grant OCE-0132903.
    Keywords: Hydraulic behaviour ; Reduced gravity model
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 670627 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    facet.materialart.
    Unknown
    Cambridge University Press
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2001. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 437 (2001): 301-323, doi:10.1017/S0022112001004402.
    Description: Laboratory and numerical experiments are used to study flow of a uniform-density fluid on the [beta]-plane around a thin zonally elongated island (or ridge segment in the abyss). This orientation is chosen specifically to highlight the roles of the zonal boundary layer dynamics in controlling the circulation around the island. There are examples of deep ocean topography that fall into this category which make the work directly applicable to oceanic flows. Linear theory for the transport around the island and the flow structure is based on a modification of the Island Rule (Pedlosky et al. 1997; Pratt & Pedlosky 1999). The linear solution gives a north–south symmetric flow around the island with novel features, including stagnation points which divide the zonal boundary layers into eastward and westward flowing zones, and a western boundary layer of vanishing length, and zonal jets. Laboratory experiments agree with the linear theory for small degrees of nonlinearity, as measured by the ratio of the inertial to Munk boundary layer scales. With increasing nonlinearity the north–south symmetry is broken. The southern stagnation point (for anticyclonic forcing) moves to the eastern tip of the island. The flow rounding the eastern tip from the northern side of the island now separates from the island. Time-dependence emerges and recirculation cells develop on the northern side of the island. Mean transport around the island is relatively unaffected by nonlinearity and given to within 20% by the modified Island Rule. Numerical solutions of the shallow water equations are in close agreement with the laboratory results. The transition from zonal to meridional island orientation occurs for island inclinations from zonal greater than about 20°.
    Description: This work was supported by the National Science Foundation (Grant Number OCE96-16949).
    Keywords: Zonal boundary layer dynamics ; Island Rule
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 904450 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2022-05-25
    Description: First published online as a Review in Advance on October 24, 2005. (Some corrections may occur before final publication online and in print)
    Description: Author Posting. © Annual Reviews, 2005. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Physiology 68 (2006): 22.1-22.29, doi:10.1146/annurev.physiol.68.040104.105418.
    Description: Superfast muscles of vertebrates power sound production. The fastest, the swimbladder muscle of toadfish, generates mechanical power at frequencies in excess of 200 Hz. To operate at these frequencies, the speed of relaxation has had to increase approximately 50-fold. This increase is accomplished by modifications of three kinetic traits: (a) a fast calcium transient due to extremely high concentration of sarcoplasmic reticulum (SR)-Ca2+ pumps and parvalbumin, (b) fast off-rate of Ca2+ from troponin C due to an alteration in troponin, and (c) fast cross-bridge detachment rate constant (g, 50 times faster than that in rabbit fast-twitch muscle) due to an alteration in myosin. Although these three modifications permit swimbladder muscle to generate mechanical work at high frequencies (where locomotor muscles cannot), it comes with a cost: The high g causes a large reduction in attached force-generating cross-bridges, making the swimbladder incapable of powering low-frequency locomotory movements. Hence the locomotory and sound-producing muscles have mutually exclusive designs.
    Description: This work was made possible by support from NIH grants AR38404 and AR46125 as well as the University of Pennsylvania Research Foundation.
    Keywords: Parvalbumin ; Ca2+ release ; Ca2+ uptake ; Cross-bridges ; Adaptation ; Sound production ; Whitman Center
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 567086 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2006. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 564 (2006): 435-454, doi:10.1017/S0022112006001522.
    Description: Motivated by work on tilted convection (Sheremet, J. Fluid Mech., vol. 506, 2004, p. 217), a set of experiments is presented here using the same set-up of a tilted tank attached to a rotating centrifuge with a 2.5 m arm. Within the tank small, almost neutrally buoyant, spheres are released, and their trajectories are recorded. Thus the forces acting on a sphere can be analysed in the case of misalignment between the buoyancy force and the axis of rotation. The angles of descent characterizing the trajectory are compared with inviscid linear theory developed by Stewartson (Q. J. Math. Appl. Mech., vol. 6, 1953, p. 141), and the agreement is found to be good. The angles should be independent of the density anomaly of the spheres compared to their environment. Using the descent velocity from non-rotating experiments, the density of the spheres is estimated and used to determine the drag acting on them in the rotating experiments. It is found that the drag is up to 50% larger than expected from Stewartson's theory. The agreement is best, not for infinitesimal, but for small Rossby numbers. The results are consistent with observations recorded by Maxworthy (J. Fluid Mech., vol. 40, 1970, p. 453).
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Publication Date: 2022-05-25
    Description: Author Posting. © Cambridge University Press, 2007. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 593 (2007): 1-32, doi:10.1017/S0022112007008415.
    Description: Results are presented from an experimental study of shallow flow in a channel partially obstructed by an array of circular cylinders. The cylinder array is a model for emergent vegetation in an open channel, but also represents a simple sparse porous medium. A shear layer with regular vortex structures forms at the edge of the array, evolving downstream to an equilibrium width and vortex size. The vortices induce nearly periodic oscillations with a frequency that matches the most unstable linear mode for a parallel shear flow. The shear layer is asymmetric about the array interface and has a two-layer structure. An inner region of maximum shear near the interface contains a velocity inflection point and establishes the penetration of momentum into the array. An outer region, resembling a boundary layer, forms in the main channel, and establishes the scale of the vortices. The vortex structure, educed by conditional sampling, shows strong crossflows with sweeps from the main channel and ejections from the array, which create significant momentum and mass fluxes across the interface. The sweeps maintain the coherent structures by enhancing shear and energy production at the interface. A linear stability analysis is consistent with the experimental results and demonstrates that the instability is excited by the differential drag between the channel and the array.
    Description: This material is based upon work supported by the National Science Foundation under Grant 0125056.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Publication Date: 2021-01-27
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Reimer, P. J., Austin, W. E. N., Bard, E., Bayliss, A., Blackwell, P. G., Ramsey, C. B., Butzin, M., Cheng, H., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Hajdas, I., Heaton, T. J., Hogg, A. G., Hughen, K. A., Kromer, B., Manning, S. W., Muscheler, R., Palmer, J. G., Pearson, C., van der Plicht, J., Reimer, R. W., Richards, D. A., Scott, E. M., Southon, J. R., Turney, C. S. M., Wacker, L., Adolphi, F., Buentgen, U., Capano, M., Fahrni, S. M., Fogtmann-Schulz, A., Friedrich, R., Koehler, P., Kudsk, S., Miyake, F., Olsen, J., Reinig, F., Sakamoto, M., Sookdeo, A., & Talamo, S. The Intcal20 Northern Hemisphere radiocarbon age calibration curve (0-55 cal kBP). Radiocarbon, 62(4), (2020): 725-757, doi:10.1017/RDC.2020.41.
    Description: Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
    Description: We would like to thank the National Natural Science Foundation of China grants NSFC 41888101 and NSFC 41731174, the 111 program of China (D19002), U.S. NSF Grant 1702816, and the Malcolm H. Wiener Foundation for support for research that contributed to the IntCal20 curve. The work on the Swiss and German YD trees was funded by the German Science foundation and the Swiss National Foundation (grant number: 200021L_157187). The operation in Aix-en-Provence is funded by the EQUIPEX ASTER-CEREGE, the Collège de France and the ANR project CARBOTRYDH (to EB). The work on the correlation of tree ring 14C with ice core 10Be was partially supported by the Swedish Research Council and the Knut and Alice Wallenberg foundation. M. Butzin was supported by the German Federal Ministry of Education and Research (BMBF) as Research for Sustainable Development (FONA; http://www.fona.de) through the PalMod project (grant number: 01LP1505B). S. Talamo and M. Friedrich are funded by the European Research Council under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement No. 803147-RESOLUTION, awarded to ST). CA. Turney would like to acknowledge support of the Australian Research Council (FL100100195 and DP170104665). P. Reimer and W. Austin acknowledge the support of the UKRI Natural Environment Research Council (Grant NE/M004619/1). T.J. Heaton is supported by a Leverhulme Trust Fellowship RF-2019-140\9. Other datasets and the IntCal20 database were created without external support through internal funding by the respective laboratories. We also would like to thank various institutions that provided funding or facilities for meetings.
    Keywords: calibration curve ; radiocarbon ; IntCal20
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    facet.materialart.
    Unknown
    Cambridge University Press | New York
    In:  http://aquaticcommons.org/id/eprint/2263 | 403 | 2015-04-28 21:06:50 | 2263
    Publication Date: 2021-07-12
    Description: Executive Summary:Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from theburning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities.Warming over this century is projected to be considerably greater than over the last century. The global average temperature since 1900 has risen by about 1.5ºF. By 2100, it is projected to rise another 2 to 11.5ºF. The U.S.average temperature has risen by a comparable amount and is very likely to rise more than the global average over this century, with some variation from place to place. Several factors will determine future temperature increases. Increases at the lower end of this range are more likely if global heat-trapping gas emissions are cut substantially. If emissions continue to rise at or near current rates, temperature increases are more likely to be near the upper end of the range. Volcanic eruptions or other natural variations could temporarily counteract some of the human-induced warming, slowing the rise in global temperature, but these effects would only last a few years.Reducing emissions of carbon dioxide would lessen warming over this century and beyond. Sizable early cuts in emissions would significantly reduce the pace and the overall amount of climate change. Earlier cuts in emissions would have a greater effect in reducing climate change than comparable reductions made later. In addition, reducing emissions of some shorter-lived heat-trapping gases, such as methane, and some types of particles, such as soot, would begin to reduce warming within weeks to decades.Climate-related changes have already been observed globally and in the United States. These include increases in air and water temperatures, reduced frost days, increased frequency and intensity of heavy downpours, a rise in sea level, and reduced snow cover, glaciers, permafrost, and seaice. A longer ice-free period on lakes and rivers, lengthening of the growing season, and increased water vapor in the atmosphere have also been observed. Over the past 30 years, temperatures have risen faster in winter than in any other season, with average winter temperatures in the Midwest and northern Great Plains increasing more than 7ºF. Some of the changes have been faster thanprevious assessments had suggested.These climate-related changes are expected to continue while new ones develop. Likely future changes for the United States and surrounding coastal waters include more intense hurricanes with related increases in wind, rain, and storm surges (but not necessarily an increase in the number of these storms that make landfall), as well as drier conditions in the Southwest and Caribbean. Thesechanges will affect human health, water supply, agriculture, coastal areas, and many other aspectsof society and the natural environment.This report synthesizes information from a wide variety of scientific assessments (see page 7) and recently published research to summarize what is known about the observed and projected consequences of climate change on the United States. It combines analysis of impacts on various sectors such as energy, water, and transportation at the national level with an assessment of key impacts on specific regions of the United States. For example, sea-level rise will increase risks of erosion, storm surge damage, and flooding for coastal communities, especially in the Southeast and parts of Alaska. Reduced snowpack and earlier snow melt will alter the timing and amount of water supplies, posingsignificant challenges for water resource managementin the West. (PDF contains 196 pages)
    Keywords: Conservation ; Management ; Pollution ; Earth Sciences ; Environment ; Policies
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 192
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  EPIC3The Species–Area Relationship, The Species–Area Relationship, Cambridge University Press, pp. 438-456
    Publication Date: 2020-11-04
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2005. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 536 (2005): 253-283, doi:10.1017/S0022112005004544.
    Description: The generation of a gravity current by the release of a semi-infinite region of buoyant fluid of depth $H$ overlying a deeper, denser and quiescent lower layer in a rotating channel of width $w$ is considered. Previous studies have focused on the characteristics of the gravity current head region and produced relations for the gravity current speed $c_{b}$ and width $w_b$ as a functions of the local current depth along the wall $h_b$, reduced gravity $g^\prime$, and Coriolis frequency $f$. Here, the dam-break problem is solved analytically by the method of characteristics assuming reduced-gravity flow, uniform potential vorticity and a semigeostrophic balance. The solution makes use of a local gravity current speed relation $c_{b} \,{=}\, c_b(h_b,\ldots)$ and a continuity constraint at the head to close the problem. The initial value solution links the local gravity current properties to the initiating dam-break conditions. The flow downstream of the dam consists of a rarefaction joined to a uniform gravity current with width $w_b$ (${\le}\, w$) and depth on the right-hand wall of $h_b$, terminated at the head moving at speed $c_b$. The solution gives $h_b$, $c_b$, $w_b$ and the transport of the boundary current as functions of $w/L_R$, where $L_R \,{=}\, \sqrt{g^\prime H}/f$ is the deformation radius. The semigeostrophic solution compares favourably with numerical solutions of a single-layer shallow-water model that internally develops a leading bore. Existing laboratory experiments are re-analysed and some new experiments are undertaken. Comparisons are also made with a three-dimensional shallow-water model. These show that lateral boundary friction is the primary reason for differences between the experiments and the semigeostrophic theory. The wall no-slip condition is identified as the primary cause of the experimentally observed decrease in gravity current speed with time. A model for the viscous decay is developed and shown to agree with both experimental and numerical model data.
    Description: This work was supported by NSF Grants OCE-0095059 and OCE-0132903.
    Keywords: Gravity current ; Dam-break problem
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 952630 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2006. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 561 (2006):103–112, doi:10.1017/S0022112006000991
    Description: A self-consistent formalism to estimate baroclinic energy densities and fluxes resulting from the propagation of internal waves of arbitrary amplitude is derived using the concept of available potential energy. The method can be applied to numerical, laboratory or field data.
    Description: MBIWE98 was supported by the US Geological Survey and the Office of Naval Research. A.S. received support from the Office of Naval Research (N00014-05-1-0361), R.B. from the Walter A. and Hope Noyes Smith Chair on Coastal Oceanography and B.B. from the US Geological Survey.
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    facet.materialart.
    Unknown
    Cambridge University Press
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2003. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 490 (2003): 189-215, doi:10.1017/S0022112003005007.
    Description: The baroclinic instability of a zonal current on the beta-plane is studied in the context of the two-layer model when the shear of the basic current is a periodic function of time. The basic shear is contained in a zonal channel and is independent of the meridional direction. The instability properties are studied in the neighbourhood of the classical steady-shear threshold for marginal stability. It is shown that the linear problem shares common features with the behaviour of the well-known Mathieu equation. That is, the oscillatory nature of the shear tends to stabilize an otherwise unstable current while, on the contrary, the oscillation is able to destabilize a current whose time-averaged shear is stable. Indeed, this parametric instability can destabilize a flow that at every instant possesses a shear that is subcritical with respect to the standard stability threshold. This is a new source of growing disturbances. The nonlinear problem is studied in the same near neighbourhood of the marginal curve. When the time-averaged flow is unstable, the presence of the oscillation in the shear produces both periodic finite-amplitude motions and aperiodic behaviour. Generally speaking, the aperiodic behaviour appears when the amplitude of the oscillating shear exceeds a critical value depending on frequency and dissipation. When the time-averaged flow is stable, i.e. subcritical, finite-amplitude aperiodic motion occurs when the amplitude of the oscillating part of the shear is large enough to lift the flow into the unstable domain for at least part of the cycle of oscillation. A particularly interesting phenomenon occurs when the time-averaged flow is stable and the oscillating part is too small to ever render the flow unstable according to the standard criteria. Nevertheless, in this regime parametric instability occurs for ranges of frequency that expand as the amplitude of the oscillating shear increases. The amplitude of the resulting unstable wave is a function of frequency and the magnitude of the oscillating shear. For some ranges of shear amplitude and oscillation frequency there exist multiple solutions. It is suggested that the nature of the response of the finite-amplitude behaviour of the baroclinic waves in the presence of the oscillating mean flow may be indicative of the role of seasonal variability in shaping eddy activity in both the atmosphere and the ocean.
    Description: J.P.’s research is supported in part by a grant from NSF, OCE 9901654.
    Keywords: Baroclinic instability ; Baroclinic waves
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 393774 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2000. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Zygote 8 (2000): 15-24, doi:10.1017/S0967199400000782.
    Description: The physiology of the early embryo may be indicative of embryo vitality and therefore methods for non-invasively monitoring physiological parameters from embryos could improve preimplantation diagnoses. The self-referencing electrophysiological technique is capable of non-invasive measurement of the physiology of individual cells by monitoring the movement of ions and molecules between the cell and the surrounding media. Here we use this technique to monitor gradients of calcium, potassium, oxygen and hydrogen peroxide around individual mouse preimplantation embryos. The calcium-sensitive electrode in self-referencing mode identified a region of elevated calcium concentration ([similar]0.25 pmol) surrounding each embryo. The calcium gradient surrounding embryos was relatively steep, such that the region of elevated calcium extended into the medium only 4 [mu]m from the embryo. By contrast, using an oxygen-sensitive electrode an extensive gradient of reduced dissolved oxygen concentration was measured surrounding the embryo and extended tens of micrometres into the medium. A gradient of neither potassium nor hydrogen peroxide was observed around unperturbed embryos. We also demonstrate that monitoring the physiology of embryos using the self-referencing technique does not compromise their subsequent development. Blastocysts studied with the self-referencing technique implanted and developed to term at the same frequency as did unexamined, control embryos. Therefore, the self-referencing electrode provides a valuable non-invasive technique for studying the physiology and pathophysiology of individual embryos without hindering their subsequent development.
    Description: A portion of this work was funded by an NIH R21 #RR 12718–02 to D.L.K. and P.J.S.S., KO81099 to D.L.K. and NIH P41 RR01395 to P.J.S.S.
    Keywords: Calcium ; Embryo physiology ; Embryo transfer ; Oxygen ; Preimplantation diagnosis
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 357072 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    facet.materialart.
    Unknown
    Cambridge University Press
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2005. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 529 (2005): 71-95, doi:10.1017/S0022112005003393.
    Description: The role of mesoscale oceanic eddies in driving large-scale currents is studied in an eddy-resolving midlatitude double-gyre ocean model. The reference solution is decomposed into large-scale and eddy components in a way which is dynamically consistent with a non-eddy-resolving ocean model. That is, the non-eddy-resolving solution driven by this eddy-forcing history, calculated on the basis of this decomposition, correctly approximates the original flow. The main effect of the eddy forcing on the large-scale flow is to enhance the eastward-jet extension of the subtropical western boundary current. This is an anti-diffusive process, which cannot be represented in terms of turbulent diffusion. It is shown that the eddy-forcing history can be approximated as a space–time correlated, random-forcing process in such a way that the non-eddy-resolving solution correctly approximates the reference solution. Thus, the random-forcing model can potentially replace the diffusion model, which is commonly used to parameterize eddy effects on the large-scale currents. The eddy-forcing statistics are treated as spatially inhomogeneous but stationary, and the dynamical roles of space–time correlations and spatial inhomogeneities are systematically explored. The integral correlation time, oscillations of the space correlations, and inhomogeneity of the variance are found to be particularly important for the flow response.
    Description: Funding for this research was provided by NSF grants OCE 0091836 and OCE 03-44094, by the Royal Society Fellowship, and by WHOI grants 27100056 and 52990035.
    Keywords: Mesoscale oceanic eddies ; Large-scale currents ; Random-forcing model
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 2965982 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2002. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 464 (2002): 251-278, doi:10.1017/S0022112002008868.
    Description: The dynamics of buoyant gravity currents in a rotating reference frame is a classical problem relevant to geophysical applications such as river water entering the ocean. However, existing scaling theories are limited to currents propagating along a vertical wall, a situation almost never realized in the ocean. A scaling theory is proposed for the structure (width and depth), nose speed and flow field characteristics of buoyant gravity currents over a sloping bottom as functions of the gravity current transport Q, density anomaly g[prime prime or minute], Coriolis frequency f, and bottom slope [alpha]. The nose propagation speed is cp [similar] cw/ (1 + cw/c[alpha]) and the width of the buoyant gravity current is Wp [similar] cw/ f(1 + cw/c[alpha]), where cw = (2Qg[prime prime or minute] f)1/4 is the nose propagation speed in the vertical wall limit (steep bottom slope) and c[alpha] = [alpha]g/f is the nose propagation speed in the slope-controlled limit (small bottom slope). The key non-dimensional parameter is cw/c[alpha], which indicates whether the bottom slope is steep enough to be considered a vertical wall (cw/c[alpha] [rightward arrow] 0) or approaches the slope-controlled limit (cw/c[alpha] [rightward arrow] [infty infinity]). The scaling theory compares well against a new set of laboratory experiments which span steep to gentle bottom slopes (cw/c[alpha] = 0.11–13.1). Additionally, previous laboratory and numerical model results are reanalysed and shown to support the proposed scaling theory.
    Description: This research was supported by NSF grant OCE-0095059.
    Keywords: Buoyant gravity currents ; Scaling theory ; Sloping bottom
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 1059929 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2022-05-26
    Description: Author Posting. © Cambridge University Press, 2003. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of the Marine Biological Association of the UK 83 (2003): 1347-1350, doi:10.1017/S0025315403008798.
    Description: Trophic positions (TP) were estimated for the blue shark (Prionace glauca), shortfin mako (Isurus oxyrinchus), thresher shark (Alopias vulpinus), and basking shark (Cetorhinus maximus) using stable isotope ratios of carbon ([delta]13C) and nitrogen ([delta]15N). The basking shark had the lowest TP (3·1) and [delta]15N value (10·4‰), whereas the thresher shark had the highest values (4·5, 15·2‰). Mako sharks showed considerable variation in TP and isotopic values, possibly due to foraging from both inshore and offshore waters. Thresher sharks were significantly more enriched in [delta]15N than blue sharks and mako sharks, suggesting a different prey base. The [delta]13C values of thresher sharks and mako sharks varied significantly, but neither was significantly different from that of blue sharks. No statistical differences were found between our TP estimations and those derived from published stomach contents analyses, indicating that stable isotope data may be used to estimate the trophic status of sharks.
    Description: This work was supported by National Marine Fisheries Service Grant NA16MF1323 to M.E.L.
    Keywords: Prionace glauca ; Isurus oxyrinchus ; Alopias vulpinus ; Cetorhinus maximus ; Trophic positions
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 129456 bytes
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Biased embryos and evolution vol. 74, 1/2, pp. 209-211
    Publication Date: 2024-01-12
    Keywords: evolution ; natural selection ; variation ; developmental bias
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/review
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Cambridge, 342 pp., Cambridge University Press, vol. 13, no. XVI:, pp. 227-235, (ISBN 3-540-43528-X)
    Publication Date: 1983
    Keywords: Textbook of geophysics ; Seismology ; Seismics (controlled source seismology) ; Waves
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Cambridge, Cambridge University Press, vol. 271, no. ALEX(01)-FR-77-01, AFTAC Contract F08606-76-C-0025, pp. 329, (ISBN: 0-08-043649-8)
    Publication Date: 1992
    Keywords: FractureT ; Chaotic behaviour ; Handbook of geophysics ; Handbook of geology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Cambridge, UK, Cambridge University Press, vol. 10, no. 1, pp. 1-40, (ISBN 0-521-84678-1 (550 pp.))
    Publication Date: 2005
    Description: ... Overall, An Introduction to Programming with Mathematica is a useful and readable book that could serve as the text for a generic programming class, a supporting text for a class on programming for geoscientists, or an introduction for experienced geoscience programmers looking for an easily readable summary of Mathematica's programming language. Experienced Mathematica programmers may find it useful as a refresher. The book's principal drawbacks are the high price of Mathematica for those who do not already have the software (although a modestly priced student version is available) and, for geoscientists in particular, a lack of relevant example problems
    Keywords: Handbook of mathematics ; computer ; algebra ; software
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  A Continent Revealed - the European Geotraverse, Cambridge, Cambridge University Press, vol. 37, pp. 33-69, (ISBN 0080419208)
    Publication Date: 1992
    Keywords: Deep seismic sounding (espec. cont. crust) ; Review article ; Earth model, also for more shallow analyses ! ; European Geotraverse ; CRUST ; earth mantle ; Muller
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Boston, 227 pp., Cambridge University Press, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN 0-521-66023-8 hc (0-521-66953-7 pb))
    Publication Date: 1982
    Keywords: Textbook of geophysics ; Seismics (controlled source seismology)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Cambridge, Cambridge University Press, vol. 3, pp. 6322, (ISBN 0-521-79203-7)
    Publication Date: 1990
    Keywords: Textbook of physics ; Chaotic behaviour ; FractureT
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Cambridge, Cambridge University Press, vol. 34, no. 22, pp. 65-70, (ISBN 0-691-12183-4, 2005 (481 pp. + CD-ROM))
    Publication Date: 1993
    Keywords: Textbook of geophysics ; Textbook of geology ; Rock mechanics ; Physical properties of rocks ; Fracture
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Boston, 227 pp., Cambridge University Press, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN 0-521-66023-8 hc (0-521-66953-7 pb))
    Publication Date: 1983
    Keywords: Textbook of geophysics ; Seismics (controlled source seismology)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    facet.materialart.
    Unknown
    Cambridge University Press
    In:  Cambridge, Cambridge University Press, vol. 7, no. Publ. No. 12, pp. 127, (ISBN: 0521839270, 520 p.)
    Publication Date: 2005
    Description: Fundamentals of Structural Geology provides a new framework for the investigation of geological structures by integrating field mapping and mechanical analysis. Assuming a basic knowledge of physical geology, introductory calculus and physics, it emphasizes the observational data, modern mapping technology, principles of continuum mechanics, and the mathematical and computational skills, necessary to quantitatively map, describe, model, and explain deformation in Earth's lithosphere. By starting from the fundamental conservation laws of mass and momentum, the constitutive laws of material behavior, and the kinematic relationships for strain and rate of deformation, the authors demonstrate the relevance of solid and fluid mechanics to structural geology. This book offers a modern quantitative approach to structural geology for advanced students and researchers in structural geology and tectonics. It is supported by a website hosting images from the book, additional colour images, student exercises and MATLAB scripts. Solutions to the exercises are available to instructors
    Keywords: Structural geology ; Textbook of geology ; MATLAB ; scripts ; Tectonics ; Lithosphere
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2020-08-26
    Description: The paper describes the architecture for a data repository and distribution system to be used in the case of a SETI detection event. This system is conceptually modelled after the Deep Space Network, although the hardware and infrastructure involved are different and substantially less expensive to operate. The system is designed to accommodate a large number of users from a variety of fields who wish to contribute to the analysis and comprehension effort that would follow the detection of an information-bearing signal.
    Print ISSN: 1473-5504
    Electronic ISSN: 1475-3006
    Topics: Biology , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2020-08-26
    Description: Under the potential to reconstruct the past climatic and atmospheric conditions from a deep ice core in the coastal Antarctic site (Styx Glacier), an 8.84 m long firn core (73°50.975′ S, 163°41.640′ E; 1623 m a.s.l.) was initially studied to propose a reliable age scale for the local estimation of snow accumulation rate. The seasonal variations of δ18O, methanesulfonic acid (MSA) and non-sea-salt sulfate (nssSO42–) were used for the firn core dating and revealed 25 annual peaks (from 1990 to 2014) with volcanic sulfate signal. The observed declining trend in annual accumulation rate with a mean value of 146 ± 60 kg m–2 a–1 is likely to be linked to the changes of sea-ice extent in the Ross Sea region. Moreover, the temporal variation of the annual mean δ18O, an annual flux of MSA and nssSO42– also likely to be under the influence of ice-covered and open water area. This study suggests a potential to recover past changes in an oceanic environment and will be useful for the interpretation of the long ice core drilled at the same site.
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2020-01-01
    Description: The various crises that have emerged since 2000 are driven by an increasing maladaptation of our societies’ information processing capabilities to the dynamics in which our societies find themselves. These capabilities have been built up path dependently over centuries, and to understand them we need to look closely at their history. Changes in technology, demography and resource use and environmental change are all part of a co-evolution in which societies’ information processing capacities play a central role. The information and communications technology revolution has accelerated developments in all of these domains and has weakened some fundamental institutions. This paper discusses how these processes might affect the long-term future of our societies.
    Electronic ISSN: 2059-4798
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2020-08-27
    Description: Clouds play an important role in the Arctic surface radiative budget, impacting the seasonal evolution of Arctic sea-ice cover. We explore the large-scale impacts of springtime and early summer (March through July) cloud and radiative fluxes on sea ice by comparing these fluxes to seasonal ice volume losses over the central Arctic basin, calculated for available observational years 2004–2007 (ICESat) and 2011–2017 (CryoSat-2). We also supplement observation data with sea-ice volume computed from the Pan-Arctic Ice–Ocean Modeling and Assimilation System (PIOMAS) during summer months. We find that the volume of sea ice lost over the melt season is most closely related to observed downwelling longwave radiation in March and early summer (June and July) longwave cloud radiative forcing, which together explain a large fraction of interannual variability in seasonal sea-ice volume loss (R2 = 0.71, p = 0.007). We show that downwelling longwave fluxes likely impact the timing of melt onset near the sea-ice edge, and can limit the magnitude of ice thickening from March to April. Radiative fluxes in June and July are likely critical to seasonal volume loss because modeled data show the greatest ice volume reductions occur during these months.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Publication Date: 2020-08-27
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2020-08-28
    Print ISSN: 0376-8929
    Electronic ISSN: 1469-4387
    Topics: Biology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Publication Date: 2020-07-21
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2020-07-21
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2020-07-21
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2020-07-21
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2020-07-20
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Publication Date: 2020-08-28
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2020-07-02
    Description: We present a high-resolution spatial study of ocean surface carbon dioxide partial pressure (pCO2), temperature and salinity coupled with a seismic survey performed in subpolar waters with a variable presence of glaciers along the coastal margins of Admiralty Bay and the Bransfield Strait, northern Antarctic Peninsula, during the late spring season. Three zones were identified in this bay. The shallow and relatively fresh SHALLOW GLACIER THAW zone in the inner portion of the bay had high freshwater inputs from active glacial meltwater channels, representing higher pCO2 levels (median ~438 μatm) than the shallow and relatively salty SHALLOW zone without glaciers along the margins and dominated by macroalgae communities at the bottom, which showed relatively low pCO2 levels (median ~371 μatm). The deep and relatively salty CENTRE zone was highly influenced by seawater intrusions from the Bransfield Strait, representing intermediate pCO2 levels (median ~397 μatm). The net sea-air CO2 fluxes in late spring obtained from the high-resolution surface survey in Admiralty Bay indicate a condition of near neutral air-sea CO2 flux, with a median (25–75% interquartile range) value of -0.07 mmol m-2 day-1 (ranging from -12.21 to +4.33 mmol m-2 day-1), contrasting with the slight source to the atmosphere estimated from measurements only in the CENTRE zone. This finding suggests that temperature-sensitive metabolic and physical-chemical processes may cause significant variability in the ocean surface distribution of CO2 over short shoreline distances in the northern Antarctic Peninsula.
    Print ISSN: 0954-1020
    Electronic ISSN: 1365-2079
    Topics: Biology , Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Publication Date: 2020-04-01
    Description: The objective was to elucidate the effects of dietary supplementation with guanidinoacetic acid (GAA) on performance, egg quality and the liver antioxidant activity of laying hens. A total of 128, 72-week-old ISA Brown laying hens were randomly divided into four equal groups (32 birds), and each subgroup had eight replicates (four birds/cage). The control group (GAA0) fed the basal diet with no supplements, while the other experimental groups fed the basal diets supplemented with 0.5 (GAA1), 1.0 (GAA2) and 1.5 (GAA3) g of GAA/kg diet. The experiment lasted for 6 weeks. The addition of GAA at a rate of 1.5 g kg−1 significantly increased the hen-day egg production and egg mass as compared to the control group (P = 0.016 and 0.003, respectively). Although the egg weight was not affected (P = 0.521) by the dietary supplements, the shell ratio, shell thickness, yolk index and Haugh units increased linearly with the increase in the dietary supplements of the GAA (P = 0.036, 0.001, 0.012 and 0.004, respectively). The liver MDA levels decreased linearly with the increment in the dietary levels of the GAA (P = 0.012). Birds in the GAA2 and GAA3 showed a significantly higher liver nitric oxide level (52.50 and 54.21 mg/g, respectively) when compared with GAA0 and GAA1 groups (P = 0.029). Compared to the GAA0 group, all GAA-supplemented groups showed significantly higher liver ATP levels (P = 0.047). In conclusion, the dietary GA supplements at doses of 1.0 or 1.5 g kg−1 may improve the laying performance, antioxidant activity and the status of cellular energy metabolism in laying hens.
    Print ISSN: 0021-8596
    Electronic ISSN: 1469-5146
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Publication Date: 2020-01-01
    Description: Geological, geomorphological and soil maps provide important information on the substrate as well as on the past and present physical landscape. For the intensely studied Netherlands coastal plain and Rhine–Meuse delta, many such map datasets have been compiled over the last two centuries. These mapping materials comprise older and younger legacy datasets, often fragmented over regions. They have been compiled within various research traditions and by various parties, involving geologists, soil scientists, geomorphologists and landscape archaeologists. The maps and datasets summarise overwhelming amounts of underlying data accumulated over the last few centuries, and are therefore valuable for reconstructing past landscapes. Digital-infrastructure developments have enhanced possibilities for recombining existing and new data over the last few decades, e.g. through GIS solutions such as palaeogeographical base maps, from which multiple derived map products can be generated. Integration of thematic information from various source maps and underlying data is needed to use the accumulated data diversity to its full potential and to answer applied and fundamental scientific questions. Using diverse information to compile or update maps, however, requires awareness of legacy surveying strategies and the state of knowledge at the time the original data and maps were produced. This paper reviews the soil, geological and geomorphological mapping traditions. We evaluate their products, underlying data and the reasoning behind their compilation, focusing on their use in conventional and digital palaeogeographical mapping. This helps get the most out of large quantities of legacy and modern data, a major challenge for surface and substrate digital mapping in the big-data era.
    Print ISSN: 0016-7746
    Electronic ISSN: 1573-9708
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2020-07-16
    Description: Although luminescence sensitivity of quartz grains of desert sands has been used in discriminating provenance, it still remains unclear about its spatiotemporal variations and climatic implications. In this paper, the luminescence sensitivity of quartz grains from the northern margin of the Chinese Loess Plateau (CLP) was studied using single-aliquot optically stimulated luminescence (OSL) and “pseudo” single-grain OSL measurements. Our results indicate that the OSL sensitivities have lower values in sand/loess beds and higher values in paleosols. We suggest that the variations in OSL sensitivity of quartz grains with depth on the CLP are mainly influenced by the origin of the quartz grains as they are related to the loess-sized material production processes and the migration of desert regions. More quartz grains of glacial origin with lower luminescence sensitivity, together with the reduced durations of irradiation and exposure cycles induced by shorter transport distance due to desert expansion, account for the lower luminescence sensitivity of glacial periods. Moreover, both the mountain processes and the retreat–advance of deserts are ultimately related to climatic changes, therefore, the orbital scale variations of luminescence sensitivity are controlled by glacial–interglacial oscillations on the CLP.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2020-07-15
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2020-04-01
    Description: Organic carbon (C) plays an essential role in the denitrification process as it supplies energy for N2O, N2 and CO2 producing reactions. The objectives of this study were to: (i) rank the reactivity of different C compounds found in manures based on their availability for denitrification and (ii) explore C-quality in different C sources based on their capacity to promote denitrification. Evaluation of different C-sources in promoting denitrification was conducted based on the molar ratio of CO2 production to NO3− reduction after incubation. Results of the first experiment (a 12-day investigation) showed that glucose and glucosamine were highly reactive C compounds with all applied NO3− being exhausted by day 3, and glucosamine had significantly high amount of NH4+-N present at end of the experiment. The glucose and glucosamine treatments resulted in significantly greater cumulative CO2 production, compared to the other treatments. In the second experiment (a 9-day investigation), all NO3− had been depleted by day 6 and 9 from acetic acid and glucose, respectively, and the greatest cumulative CO2 production was from acetic acid. The CO2 appearance to NO3− molar ratios revealed that glucose and glucosamine were compounds with highly available C in the first experiment. In the second experiment, the pig slurry and acetic acid were found to be C-sources that promoted potential denitrification. The application of slurry to soil results in the promotion of denitrification and this depends on the availability of the C compounds it contains. Understanding the relationship between C availability and denitrification potential is useful for developing denitrification mitigation strategies for organic soil amendments.
    Print ISSN: 0021-8596
    Electronic ISSN: 1469-5146
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Publication Date: 2020-07-08
    Description: Two satellite datasets are used to characterize winter landfast first-year sea-ice (FYI), deformed FYI (DFYI) and multiyear sea-ice (MYI) roughness in the Canadian Arctic Archipelago (CAA): (1) optical Multi-angle Imaging SpectroRadiometer (MISR) and (2) synthetic aperture radar Sentinel-1. The Normalized Difference Angular Index (NDAI) roughness proxy derived from MISR, and backscatter from Sentinel-1 are intercompared. NDAI and backscatter are also compared to surface roughness derived from an airborne LiDAR track covering a subset of FYI and MYI (no DFYI). Overall, NDAI and backscatter are significantly positively correlated when all ice type samples are considered. When individual ice types are evaluated, NDAI and backscatter are only significantly correlated for DFYI. Both NDAI and backscatter are correlated with LiDAR-derived roughness (r = 0.71 and r = 0.74, respectively). The relationship between NDAI and roughness is greater for MYI than FYI, whereas for backscatter and ice roughness, the relationship is greater for FYI than MYI. Linear regression models are created for the estimation of FYI and MYI roughness from NDAI, and FYI roughness from backscatter. Results suggest that using a combination of Sentinel-1 backscatter for FYI and MISR NDAI for MYI may be optimal for mapping winter sea-ice roughness in the CAA.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Publication Date: 2020-07-08
    Description: Drumlins form at the ice/bed interface through subglacial processes that are not directly observable. The internal stratigraphy of drumlins provides insight into how they developed and associated subglacial processes, but traditional stratigraphic logging techniques are limited to natural exposures and excavations. Using ground-penetrating radar, we imaged the internal stratigraphy of seven drumlins from a recently exposed drumlin field in the forefield of Múlajökull, Iceland. Data were collected with 100 and 200 MHz antennas with maximum resolvable depths of 8 and 4 m, respectively. Longitudinal echograms contained coherent down-ice dipping reflectors over the lengths of the drumlins. Near the drumlin heads (i.e., stoss sides), down-glacier dipping beds lie at high angles to the surface, whereas on the lee sides, the down-glacier dipping beds lie at low angles, or conform, to drumlin surfaces. Transverse echograms exhibited unconformities along the flanks of drumlin heads and conformable bedding across the lee side widths of the drumlins. These observations were ground-truthed with stratigraphic logs from a subset of drumlins and good agreement was found. The stratigraphic patterns support previous conclusions that drumlins at Múlajökull formed on a deformable bed through both depositional and erosional processes which may alternate between its surge and quiescent phases.
    Print ISSN: 0022-1430
    Electronic ISSN: 1727-5652
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2020-07-08
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2020-07-08
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Publication Date: 2020-07-08
    Description: The Souter Head sub-volcanic complex (Aberdeenshire, Scotland) intruded the high-grade metamorphic core of the Grampian Orogen at 469.1 ± 0.6 Ma (uranium-238–lead-206 (238U–206Pb) zircon). It follows closely peak metamorphism and deformation in the Grampian Terrane and tightly constrains the end of the Grampian Event of the Caledonian Orogeny. Temporally coincident U–Pb and argon/argon (40Ar/39Ar) data show the complex cooled quickly with temperatures decreasing from ca.800 °C to less than 200 °C within 1 Ma. Younger rhenium–osmium (Re–Os) ages are due to post-emplacement alteration of molybdenite to powellite. The U–Pb and Ar/Ar data combined with existing geochronological data show that D2/D3 deformation, peak metamorphism (Barrovian and Buchan style) and basic magmatism in NE Scotland were synchronous at ca.470 Ma and are associated with rapid uplift (5–10 km Ma−1) of the orogen, which, by ca.469 Ma, had removed the cover to the metamorphic pile. Rapid uplift resulted in decompressional melting and the generation of mafic and felsic magmatism. Shallow slab break-off (50–100 km) is invoked to explain the synchroneity of these events. This interpretation implies that peak metamorphism and D2/D3 ductile deformation were associated with extension. Similarities in the nature and timing of orogenic events in Connemara, western Ireland, with NE Scotland suggest that shallow slab break-off occurred in both localities.
    Print ISSN: 1755-6910
    Electronic ISSN: 1755-6929
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2020-07-09
    Description: Ancient cities are excellent spatiotemporal indicators for the study of historical human activities and environmental change. The ancient city of Sanchahe is located at the southern margin of the Mu Us Desert, China. It is an ideal location for studying the complex relationships between historical desertification and human activities. Field observations of the ancient city walls, a well, and a spring, as well as 14C dating, grain size, spatial analysis of archaeological sites, and analyses of historical seismicity, indicated that neotectonics may have contributed to crustal uplift and accelerated fluvial incision of the Wuding River. This rapid incision caused a decline in groundwater levels, which is an important reason for the irreversible environmental degradation around Sanchahe city over the past 800 yr. This study provides new evidence for such environmental degradation and may contribute to a better understanding of historical desertification in the Mu Us Desert.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2020-07-08
    Description: We study climate change policies using the novel pattern scaling approach of regional transient climate response in order to develop a regional economy–climate model under conditions of deep uncertainty. We associate welfare weights with regions and analyze cooperative outcomes derived by the social planner's solution at the regional scale. Recent literature indicates that damages are larger in low latitude (warmer) areas and are projected to become relatively even larger in low latitude areas than at temperate latitudes. Under deep uncertainty, robust control policies are more conservative regarding emissions and, when regional distributional weights are introduced, carbon taxes are lower in the relatively poorer region. Mild concerns for robustness are welfare improving for the poor region, while strong concerns have welfare cost for all regions. We show that increasing regional temperatures will increase resources devoted to learning, in order to reduce deep uncertainty.
    Print ISSN: 1355-770X
    Electronic ISSN: 1469-4395
    Topics: Economics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2020-07-08
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2020-07-08
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Publication Date: 2020-07-09
    Description: A Fast Ice Prediction System (FIPS) was constructed and is the first regional land-fast sea-ice forecasting system for the Antarctic. FIPS had two components: (1) near-real-time information on the ice-covered area from MODIS and SAR imagery that revealed, tidal cracks, ridged and rafted ice regions; (2) a high-resolution 1-D thermodynamic snow and ice model (HIGHTSI) that was extended to perform a 2-D simulation on snow and ice evolution using atmospheric forcing from ECMWF: either using ERA-Interim reanalysis (in hindcast mode) or HERS operational 10-day predictions (in forecast mode). A hindcast experiment for the 2015 season was in good agreement with field observations, with a mean bias of 0.14 ± 0.07 m and a correlation coefficient of 0.98 for modeled ice thickness. The errors are largely caused by a cold bias in the atmospheric forcing. The thick snow cover during the 2015 season led to modeled formation of extensive snow ice and superimposed ice. The first FIPS operational service was performed during the 2017/18 season. The system predicted a realistic ice thickness and onset of snow surface melt as well as the area of internal ice melt. The model results on the snow and ice properties were considered by the captain of R/V Xuelong when optimizing a low-risk route for on-ice transportation through fast ice to the coastal Zhongshan Station.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2020-07-09
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Publication Date: 2020-07-08
    Description: The evolution of melt ponds on Arctic sea ice in summer is one of the main factors that affect sea-ice albedo and hence the polar climate system. Due to the different spectral properties of open water, melt pond and sea ice, the melt pond fraction (MPF) can be retrieved using a fully constrained least-squares algorithm, which shows a high accuracy with root mean square error ~0.06 based on the validation experiment using WorldView-2 image. In this study, the evolution of ponds on first-year and multiyear ice in the Canadian Arctic Archipelago was compared based on Sentinel-2 and Landsat 8 images. The relationships of pond coverage with air temperature and albedo were analysed. The results show that the pond coverage on first-year ice changed dramatically with seasonal maximum of 54%, whereas that on multiyear ice changed relatively flat with only 30% during the entire melting period. During the stage of pond formation, the ponds expanded rapidly when the temperature increased to over 0°C for three consecutive days. Sea-ice albedo shows a significantly negative correlation (R = −1) with the MPF in melt season and increases gradually with the refreezing of ponds and sea ice.
    Print ISSN: 0260-3055
    Electronic ISSN: 1727-5644
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...